Note: Descriptions are shown in the official language in which they were submitted.
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TRANSMITTING / RECEIVING SYSTEMS AND BROADCASTING SIGNAL
PROCESSING METHOD
This is a divisional of Canadian National Phase Patent
Application No. 2,751,711 filed on March 15, 2010.
BACKGROUND OF THE INVENTION
1. The field
[0001] The present invention relates to a digital
broadcasting system for transmitting and receiving digital
broadcast signal, and more particularly, to a transmitting
system for processing and transmitting digital broadcast
signal, and a receiving system for receiving and processing
digital broadcast signal and, a method of processing digital
broadcast signal in the transmitting system and the receiving
system.
Discussion of the Related Art
[0002] The Vestigial Sideband (VSB) transmission mode,
which is adopted as the standard for digital broadcasting in
North America and the Republic of Korea, is a system using a
single carrier method. Therefore, the receiving performance of
the digital broadcast receiving system may be deteriorated in a
poor channel environment. Particularly, since resistance to
changes in channels and noise is more highly required when
using portable and/or mobile broadcast receivers, the receiving
performance may be even more deteriorated when transmitting
mobile service data by the VSB transmission mode.
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SUMMARY OF THE INVENTION
[0002a] According to an aspect of the present disclosure,
there is provided a receiving system comprising: a receiving
unit for receiving broadcast service data for a service and
signaling information for signaling the service; a first
deinterleaver for convolutional de-interleaving the received
broadcast service data and signaling information; a second
deinterleaver for block de-interleaving the convolutional de-
interleaved broadcast service data and signaling information;
and a decoder for decoding the: block de-interleaved broadcast
service data and signaling information, wherein the service
includes at least one component delivered in a transport
session, wherein the signaling information includes service
identification information for identifying the service and
session identification information for identifying the
=
transport session.
[0002b] According to another aspect of the present.
disclosure, there is provided a method of processing data in a
receiving system, the method comprising: receiving broadcast
service data for a service and signaling information for
signaling the service; convolutional de-interleaving the
received broadcast service data and signaling information;
block de-interleaving the convolutional de-interleaved
broadcast service data and signaling information; and decoding
the block de-interleaved broadcast service data and signaling
information, wherein the service includes at least one
component delivered in a transport session, wherein the
signaling information includes service identification
information for identifying the service and session
identification information for identifying the transport
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session.
[0002c] According to another. aspect, there is provided a
transmitting system comprising: an encoder for encoding
broadcast service data for a service and signaling information
for signaling the service; a first interleaver for block
interleaving the encoded broadcast service data and signaling
information; a second interleaver for convolutional
interleaving the block-interleaved broadcast service data and
signaling information; and a transmitting unit for transmitting
a broadcast signal including the convolutional interleaved
broadcast service data and signaling information, wherein the
service includes at least one component that is delivered in a
transport session, wherein the signaling information includes
service identification information for identifying the service
and session identification information for identifying the
transport session.
[0002d] According to another aspect, there is provided a
method of processing data in a transmitting system, the method
comprising: encoding broadcast service data for a service and
signaling information for signaling the service; block
interleaving the encoded broadcast service data and signaling
information; convolutional interleaving the block-interleaved
broadcast service data and signaling information; and
transmitting a broadcast signal including the convolutional
interleaved broadcast service data and signaling information,
wherein the service includes at least one component that is
delivered in a transport session, wherein the signaling
information includes service identification information for
identifying the service and session identification information
for identifying the transport session.
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[0003] Some embodiments may provide a transmitting system
and a receiving system and a method of processing broadcast
signal that are highly resistant to channel changes and noise.
[0004] Some embodiments may provide a transmitting system
and a receiving system and a method of processing broadcast
signal that can enhance the receiving performance of the
receiving system by performing additional encoding on mobile
service data and by transmitting the processed data to the
receiving system.
[0005] Some embodiments may provide a transmitting system
and a receiving system and a method of processing broadcast
signal that can also enhance the receiving performance of the
receiving system by inserting known data already known in
accordance with a pre-agreement between the receiving system
and the transmitting system in a predetermined region within a
data region.
[0006] Some embodiments may provide a transmitting system, a
receiving system, and a method for processing broadcast signals
that can enhance the receiving performance by signaling
information that can identify a source of a component
configuring a mobile service.
[0007] Some embodiments may provide a transmitting system, a
receiving system, and a method- for processing broadcast signals
that can enhance the receiving performance by performing error
detection once again on a error-correction decoded RS frame and
by signaling the error-detected result.
[0008] In another aspect, a receiving system includes a
tuner, a demodulator, a block decoder, an RS frame decoder, and
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a service manager. The tuner receives a broadcast signal,
wherein the broadcast signal includes mobile service data, a
service map table signaling access information of the mobile
service data, and a plurality of known data sequences, and
wherein the mobile service data and the service map table are
packetized to an RS frame. The demodulator demodulates the
received broadcast signal. The block decoder turbo-decodes the
mobile service data and the service map table included in the
demodulated broadcast signal in block units. The RS frame
decoder forms an RS frame including the turbo-decoded mobile
service data and service map table, performs primary first
cyclic redundancy check (CRC)-decoding and RS-decoding, and
performs secondary CRC-decoding on the primarily CRC-decoded
and RS-decoded RS frame. The service manager acquires source
IP address information of IP datagrams of the RS frame-decoded
mobile service data from the service map
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table. The handler uses the source IP address information so
as to decode the IP datagrams of the mobile service data.
[0009] A payload of the primarily CRC-decoded and RS-
decoded RS frame may include 187 M/H service data packets.
Herein, each M/H service data packet may include a 2-byte M/H
header, k number of stuffing bytes (wherein lc-0), and a (N-
2-k)-byte M/H payload, and the M/H header may include an
error indicator (error indicator) field marking whether or
not an error exists in the corresponding M/H service data
packet.
[0010] The RS frame decoder may mark and output the
presence of an error in an error_indicator field of the M/H
service data packet corresponding to the row verified to have
a CRC error existing therein, after performing secondary CRC-
decoding.
[0011] The RS frame decoder may perform derandomizing on
the payload of the secondarily CRC-decoded RS frame, after
performing the secondary CRC-decoding.
[0012] The M/H header may further include a stuffing
indicator (stuffing_indicator) field indicating whether or
not a stuffing byte has been inserted, and, when the
stuffing indicator field indicates that a stuffing byte has
been inserted, the value of k may be greater than '0'.
[0013] The service map table may include a mobile service
loop providing access information of a mobile service level
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and a component loop providing access information of a
component level.
[0014] The source IP address information of an IP datagram
of the mobile service data may be signaled to the component
loop.
[0015] When the component being signaled to the component
loop is a FLUTE component, the service manager may acquire a
transport session identifier (TSI) of the FLUTE component
from a component descriptor included in the component loop.
[0016] The RS frame may be divided into multiple portions,
wherein each portion is mapped to a respective data group so
as to be received. Herein, the data group may include data
of a respective portion, a plurality of known data sequences,
and a transmission parameter, and the transmission parameter
may include fast information channel (FTC) data including
cross-layer information for acquiring a mobile service and
transmission parameter channel (TPC) data including FTC
version information that can identify an update of the FTC.
Herein, the transmission parameter may be positioned between
a first known data sequence and a second known data sequence
among the plurality of known data sequences.
[0017] The receiving system may further include a known
sequence detector detecting a plurality of known data
sequences from the data group, and an equalizer channel-
equalizing the demodulated broadcast signal using at least
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one known data sequence among the plurality of detected known
data sequences.
[0018] In another aspect, a method of processing a broadcast
signal in a receiving system includes receiving a broadcast
signal, wherein the broadcast signal includes mobile service
data, a service map table signaling access information of the
mobile service data, and multiple known data sequences, and
wherein the mobile service data and the service map table are
packetized to an RS frame, demodulating the received broadcast
signal, turbo-decoding the mobile service data and the service
map table included in the demodulated broadcast signal in block
units, configuring an RS frame including the turbo-decoded
mobile service data and service map table, performing primary
first cyclic redundancy check (CRC)-decoding and RS-decoding,
and performing secondary CRC-decoding on the primarily CRC-
decoded and RS-decoded RS frame, acquiring source IP address
information of IP datagrams of the RS frame-decoded mobile
service data from the service map table, and using the source
IP address information so as to decode the IP datagrams of the
mobile service data.
[0019] It is to be understood that both the foregoing
general description and the following detailed description of
some embodiments of the present invention are exemplary and
explanatory and are intended to provide further explanation of
the embodiments as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 illustrates a structure of a M/H frame for
transmitting and receiving mobile service data according to an
embodiment of the present invention;
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[0021] FIG. 2 illustrates an exemplary structure of a
VSB frame;
[0022] FIG. 3 illustrates a mapping example of the positions
to which the first 4 slots of a sub-frame are assigned with
respect to a VSB frame in a space region;
[0023] FIG. 4 illustrates a mapping example of the positions
to which the first 4 slots of a sub-frame are assigned with
respect to a VSB frame in a time region;
[0024] FIG. 5 illustrates an alignment of data after being
data interleaved and identified;
[0025] FIG. 6 illustrates an enlarged portion of the data
group shown in FIG. 5 for a better understanding of the present
invention;
[0026] FIG. 7 illustrates an alignment of data before being
data interleaved and identified;
[0027] FIG. 8 illustrates an enlarged portion of the data
group shown in FIG. 7 for a better understanding of the present
invention;
[0028] FIG. 9 illustrates an exemplary assignment order of
data groups being assigned to one of 5 sub-frames according to
an embodiment of the present invention;
[0029] FIG. 10 illustrates an example of assigning a single
parade to an M/H frame according to an embodiment of the
present invention;
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[0030] FIG. 11 illustrates an example of assigning 3 parades
to an M/H frame according to an embodiment of the present
invention;
[0031] FIG. 12 illustrates an example of expanding the
assignment process of 3 parades to 5 sub-frames within an M/H
frame;
[0032] FIG. 13 illustrates a data transmission structure
according to an embodiment of the present invention, wherein
signaling data are included in a data group so as to be
transmitted;
[0033] FIG. 14 illustrates a block diagram showing a general
structure of a transmitting system according to an embodiment
of the present invention;
[0034] FIG. 15 is a diagram illustrating an example of RS
frame payload according to an embodiment of the present
invention;
[0035] FIG. 16 is a diagram illustrating a structure of an
M/H header within an M/H service data packet according to an
embodiment of the present invention;
[0036] FIG. 17(a) and FIG. 17(b) are diagrams illustrating
another example of RS frame payload according to an embodiment
of the present invention; and
[0037] FIG. 18 illustrates a block diagram showing an
example of a service multiplexer of FIG. 14;
[0038] FIG. 19 illustrates a block diagram showing an
embodiment of a transmitter of FIG. 14;
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[0039] FIG. 20 illustrates a block diagram showing an
example of a pre-processor of FIG. 19;
[0040] FIG. 21 illustrates a conceptual block diagram of the
M/H frame encoder of FIG. 20;
[0041] FIG. 22 illustrates a detailed block diagram of an RS
frame encoder of FIG. 21;
[0042] FIG. 23(a) and FIG. 23(b) illustrate a process of one
or two RS frame being divided into several portions, based upon
an RS frame mode value, and a process of each portion being
assigned to a corresponding region within the respective data
group;
[0043] FIG. 24(a) to FIG. 24(c) illustrate error correction
encoding and error detection encoding processes according to an
embodiment of the present invention;
[0044] FIG. 25(a) to FIG. 25(d) illustrate an example of
performing a row permutation (or interleaving) process in super
frame units according to an embodiment of the present
invention;
[0045] FIG. 26(a) and FIG. 26(b) illustrate an example which
a parade configures of two RS frames;
[0046] FIG. 27(a) and FIG. 27(b) illustrate an exemplary
process of dividing an RS frame for configuring a data group
according to an embodiment of the present invention;
[0047] FIG. 28 illustrates a block diagram of a block
processor according to an embodiment of the present invention;
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[0048] FIG. 29 illustrates a detailed block diagram of a
convolution encoder of the block processor;
[0049] FIG. 30 illustrates a symbol interleaver of the block
processor;
[0050] FIG. 31 illustrates a block diagram of a group
formatter according to an embodiment of the present invention;
[0051] FIG. 32 illustrates a block diagram of a trellis
encoder according to an embodiment of the present invention;
[0052] FIG. 33 illustrates an example of assigning signaling
information area according to an embodiment of the present
invention;
[0053] FIG. 34 illustrates a detailed block diagram of a
signaling encoder according to an embodiment of the present
invention;
[0054] FIG. 35 illustrates an example of a syntax structure
of TPC data according to an embodiment of the present
invention;
[0055] FIG. 36 illustrates an example of a transmission
scenario of the TPC data and the FIC data level according to an
embodiment of the present invention;
[0056] FIG. 37 illustrates a syntax structure of an FIC
chunk according to an embodiment of the present invention;
[0057] FIG. 38 illustrates a syntax structure of an FIC
chunk header according to an embodiment of the present
invention;
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[0058] FIG. 39 illustrates a syntax structure of an FIC
chunk payload according to an embodiment of the present
invention;
[0059] FIG. 40 illustrates a syntax structure of an FIC
segment header according to an embodiment of the present
invention;
[0060] FIG. 41 illustrates a syntax structure of a service
map table (SMT) according to an embodiment of the present
invention;
[0061] FIG. 42 illustrates a bitstream syntax structure of
component descriptor() according to an embodiment of the
present invention;
[0062] FIG. 43 illustrates a bitstream syntax structure of
component data() providing data for FLUTE file delivery
according to an embodiment of the present invention;
[0063] FIG. 44 illustrates an example of power saving of in
a receiver when transmitting 3 parades to an M/H frame level
according to an embodiment of the present invention;
[0064] FIG. 45 illustrates an example of a training sequence
at the byte level according to an embodiment of the present
invention;
[0065] FIG. 46 illustrates an example of a training sequence
at the symbol according to an embodiment of the present
invention;
[0066] FIG. 47 illustrates a block diagram of a receiving
system according to an embodiment of the present invention;
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[0067] FIG. 48 is a block diagram showing an example of a
baseband operation controller of FIG. 47;
[0068] FIG. 49 illustrates an example of linear
interpolation according to an embodiment of the present
invention;
[0069] FIG. 50 illustrates an example of linear
extrapolation according to an embodiment of the present
invention;
[0070] FIG. 51 illustrates a block diagram of a channel
equalizer according to an embodiment of the present invention;
[0071] FIG. 52 illustrates a block diagram of a block
decoder according to an embodiment of the present invention;
[0072] FIG. 53(a) and FIG. 53(b) illustrate an exemplary
process of configuring one or two RS frame by collecting a
plurality of portions according to an embodiment of the present
invention;
[0073] FIG. 54 and FIG. 55 illustrate process steps of error
correction decoding according to an embodiment of the present
invention; and
[0074] FIG. 56 illustrates process steps of error correction
decoding according to another embodiment of the present
invention.
DETAILED DESCRIPTION OF EMBODIMENTS
[0075] Reference will now be made in detail to the preferred
embodiments of the present invention, examples of which are
illustrated in the accompanying drawings. Wherever possible,
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the same reference numbers will be used throughout the drawings
to refer to the same or like parts.
[0076] In addition, although the terms used in the present
invention are selected from generally known and used terms,
some of the terms mentioned in the description of the present
invention have been selected by the applicant at his or her
discretion, the detailed meanings of which are described in
relevant parts of the description herein. Furthermore, it is
required that the present invention is understood, not simply
by the actual terms used but by the meaning of each term lying
within.
[0077] Among the terms used in the description of the
present invention, main service data correspond to data that
can be received by a fixed receiving system and may include
audio/video (A/V) data. More specifically, the main service
data may include A/V data of high definition (HD) or standard
definition (SD) levels and may also include diverse data types
required for data broadcasting. Also, the known data
correspond to data pre-known in accordance with a pre-arranged
agreement between the receiving system and the transmitting
system.
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[0078]
Additionally, among the terms used in the present
invention, "M/H (or NH)" corresponds to the initials of
"mobile" and "handheld" and represents the opposite concept
of a fixed-type system.
Furthermore, the M/H service data
may include at least one of mobile service data and handheld
service data, and will also be referred to as "mobile service
data" for simplicity.
Herein, the mobile service data not
only correspond to M/H service data but may also include any
type of service data with mobile or portable characteristics.
Therefore, the mobile service data according to the present
invention are not limited only to the M/H service data.
[0079]
The above-described mobile service data may
correspond to data having information, such as program
execution files, stock information, and so on, and may also
correspond to A/V data.
Most particularly, the mobile
service data may correspond to A/V data having lower
resolution and lower data rate as compared to the main
service data. For example, if an A/V codec that is used for
a conventional main service corresponds to a MPEG-2 codec, a
MPEG-4 advanced video coding (AVC) or scalable video coding
(SVC) having better image compression efficiency may be used
as the A/V codec for the mobile service.
Furthermore, any
type of data may be transmitted as the mobile service data.
For example, transport protocol expert group (TPEG) data for
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broadcasting real-time transportation information may be
transmitted as the main service data.
[0080] Also, a data service using the mobile service data
may include weather forecast services, traffic information
services, stock information services, viewer participation
quiz programs, real-time polls and surveys, interactive
education broadcast programs, gaming services, services
providing information on synopsis, character, background
music, and filming sites of soap operas or series, services
providing information on past match scores and player
profiles and achievements, and services providing information
on product information and programs classified by service,
medium, time, and theme enabling purchase orders to be
processed. Herein, the present invention is not limited only
to the services mentioned above.
[0081] In the present invention, the transmitting system
provides backward compatibility in the main service data so
as to be received by the conventional receiving system.
Herein, the main service data and the mobile service data are
multiplexed to the same physical channel and then transmitted.
[0082] Furthermore, the transmitting system according to
the present invention performs additional encoding on the
mobile service data and inserts the data already known by the
receiving system and transmitting system (e.g., known data),
thereby transmitting the processed data.
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[0083]
Therefore, when using the transmitting system
according to the present invention, the receiving system may
receive the mobile service data during a mobile state and may
also receive the mobile service data with stability despite
various distortion and noise occurring within the channel.
M/H Frame Structure
[0084] In
the embodiment of the present invention, the
mobile service data are first multiplexed with main service
data in M/H frame units and, then, modulated in a VSB mode
and transmitted to the receiving system.
[0085] At
this point, one M/H frame configures of K1
number of sub-frames, wherein one sub-frame includes K2
number of slots.
Also, each slot may be configured of K3
number of data packets. In
the embodiment of the present
invention, K1 will be set to 5, K2 will be set to 16, and K3
will be set to 156 (i.e., K1=5, K2=16, and K3=156).
The
values for Kl, K2, and K3 presented in this embodiment either
correspond to values according to a preferred embodiment or
are merely exemplary. Therefore, the above-mentioned values
will not limit the scope of the present invention.
[0086]
FIG. 1 illustrates a structure of an M/H frame for
transmitting and receiving mobile service data according to
the present invention. In
the example shown in FIG. 1, one
M/H frame consists of 5 sub-frames, wherein each sub-frame
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. .
includes 16 slots. In this case, the M/H frame according to
the present invention includes 5 sub-frames and 80 slots.
[0087]
Also, in a packet level, one slot is configured of
156 data packets (i.e., transport stream packets), and in a
symbol level, one slot is configured of 156 data segments.
Herein, the size of one slot corresponds to one half (1/2) of
a VSB field.
More specifically, since one 207-byte data
packet has the same amount of data as a data segment, a data
packet prior to being interleaved may also be used as a data
segment.
[0088]
At this point, two VSB fields are grouped to form a
VSB frame.
[0089]
FIG. 2 illustrates an exemplary structure of a VSB
frame, wherein one VSB frame consists of 2 VSB fields (i.e.,
an odd field and an even field).
Herein, each VSB field
includes a field synchronization segment and 312 data
segments.
[0090]
The slot corresponds to a basic time period for
multiplexing the mobile service data and the main service
data. Herein, one slot may either include the mobile service
data or be configured only of the main service data.
[0091] If one M/H frame is transmitted during one slot,
the first 118 data packets within the slot correspond to a
data group.
And, the remaining 38 data packets become the
main service data packets. In another example, when no data
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group exists in a slot, the corresponding slot is configured
of 156 main service data packets.
[0092]
Meanwhile, when the slots are assigned to a VSB
frame, an offset exists for each assigned position.
[0093]
FIG. 3 illustrates a mapping example of the
positions to which the first 4 slots of a sub-frame are
assigned with respect to a VSB frame in a space region. And,
FIG. 4 illustrates a mapping example of the positions to
which the first 4 slots of a sub-frame are assigned with
respect to a VSB frame in a time region.
[0094]
Referring to FIG. 3 and FIG. 4, a 38th data packet
(TS packet #37) of a 1st slot (Slot #0) is mapped to the 1st
data packet of an odd VSB field. A
38th data packet (TS
packet #37) of a 2nd slot (Slot #1) is mapped to the 157th data
packet of an odd VSB field.
Also, a 38th data packet (TS
packet #37) of a 3"d slot (Slot #2) is mapped to the 1st data
packet of an even VSB field.
And, a 38th data packet (TS
packet #37) of a 4th slot (Slot #3) is mapped to the 157th data
packet of an even VSB field.
Similarly, the remaining 12
slots within the corresponding sub-frame are mapped in the
subsequent VSB frames using the same method.
[0095]
Meanwhile, one data group may be divided into at
least one or more hierarchical regions. And, depending upon
the characteristics of each hierarchical region, the type of
mobile service data being inserted in each region may vary.
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For example, the data group within each region may be divided
(or categorized) based upon the receiving performance.
[0096] In
an example given in the present invention, a
data group is divided into regions A, B, C, and D in a data
configuration after data interleaving.
[0097]
FIG. 5 illustrates an alignment of data after being
data interleaved and identified.
FIG. 6 illustrates an
enlarged portion of the data group shown in FIG. 5 for a
better understanding of the present invention.
FIG. 7
illustrates an alignment of data before being data
interleaved and identified.
And, FIG. 8 illustrates an
enlarged portion of the data group shown in FIG. 7 for a
better understanding of the present invention. More
specifically, a data structure identical to that shown in FIG.
is transmitted to a receiving system. In other words, one
data packet is data-interleaved so as to be scattered to a
plurality of data segments, thereby being transmitted to the
receiving system. FIG. 5 illustrates an example of one data
group being scattered to 170 data segments. At this point,
since one 207-byte packet has the same amount of data as one
data segment, the packet that is not yet processed with data-
interleaving may be used as the data segment.
[0098]
FIG. 5 shows an example of dividing a data group
prior to being data-interleaved into 10 M/H blocks (i.e., M/H
block 1 (B1) to M/H block 10 (B10)). In
this example, each
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,
M/H block has the length of 16 segments. Referring to FIG. 5,
only the RS parity data are allocated to a portion of 5
segments before the M/H block 1 (B1) and 5 segments behind
the M/H block 10 (B10). The RS parity data are excluded in
regions A to D of the data group.
[0099] More
specifically, when it is assumed that one data
group is divided into regions A, B, C, and D, each M/H block
may be included in any one of region A to region D depending
upon the characteristic of each M/H block within the data
group.
At this point, according to an embodiment of the
present invention, each M/H block may be included in any one
of region A to region D based upon an interference level of
main service data.
[00100] Herein,
the data group is divided into a plurality
of regions to be used for different purposes.
More
specifically, a region of the main service data having no
interference or a very low interference level may be
considered to have a more resistant (or stronger) receiving
performance as compared to regions having higher interference
levels.
Additionally, when using a system inserting and
transmitting known data in the data group, wherein the known
data are known based upon an agreement between the
transmitting system and the receiving system, and when
consecutively long known data are to be periodically inserted
in the mobile service data, the known data having a
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predetermined length may be periodically inserted in the
region having no interference from the main service data
(i.e., a region wherein the main service data are not mixed).
However, due to interference from the main service data, it
is difficult to periodically insert known data and also to
insert consecutively long known data to a region having
interference from the main service data.
[00101]
Referring to FIG. 5, M/H block 4 (B4) to M/H block
7 (B7) correspond to regions without interference of the main
service data.
M/H block 4 (B4) to M/H block 7 (B7) within
the data group shown in FIG. 5 correspond to a region where
no interference from the main service data occurs.
In this
example, a long known data sequence is inserted at both the
beginning and end of each M/H block.
In the description of
the present invention, the region including M/H block 4 (B4)
to M/H block 7 (B7) will be referred to as "region A
(=B4+B5+B6+B7)".
As described above, when the data group
includes region A having a long known data sequence inserted
at both the beginning and end of each M/H block, the
receiving system is capable of performing equalization by
using the channel information that can be obtained from the
known data. Therefore, the strongest equalizing performance
may be yielded (or obtained) from one of region A to region D.
[00102] In the example of the data group shown in FIG. 5,
M/H block 3 (B3) and M/H block 8 (B8) correspond to a region
21
CA 02888511 2015-04-20
having little interference from the main service data.
Herein, a long known data sequence is inserted in only one
side of each M/H block B3 and B8. More specifically, due to
the interference from the main service data, a long known
data sequence is inserted at the end of M/H block 3 (B3), and
another long known data sequence is inserted at the beginning
of M/H block 8 (B8).
In the present invention, the region
including M/H block 3 (B3) and M/H block 8 (B8) will be
referred to as "region B(=B3+88)". As described above, when
the data group includes region B having a long known data
sequence inserted at only one side (beginning or end) of each
M/H block, the receiving system is capable of performing
equalization by using the channel information that can be
obtained from the known data.
Therefore, a stronger
equalizing performance as compared to region C/D may be
yielded (or obtained).
[00103]
Referring to FIG. 5, M/H block 2 (B2) and M/H block
9 (B9) correspond to a region having more interference from
the main service data as compared to region B. A long known
data sequence cannot be inserted in any side of M/H block 2
(B2) and M/H block 9 (B9). Herein, the region including M/H
block 2 (B2) and M/H block 9 (B9) will be referred to as
"region C(=B2+B9)". Finally, in the example shown in FIG. 5,
M/H block 1 (B1) and M/H block 10 (B10) correspond to a
region having more interference from the main service data as
22
CA 02888511 2015-04-20
. .
compared to region C. Similarly, a long known data sequence
cannot be inserted in any side of M/H block 1 (B1) and M/H
block 10 (B10).
[00104]
Herein, the region including M/H block 1 (B1) and
M/H block 10 (B10) will be referred to as "region D
(=B1+B10)".
Since region C/D is spaced further apart from
the known data sequence, when the channel environment
undergoes frequent and abrupt changes, the receiving
performance of region C/D may be deteriorated.
[00105]
FIG. 7 illustrates a data structure prior to data
interleaving. More specifically, FIG. 7 illustrates an
example of 118 data packets being allocated to a data group.
FIG. 7 shows an example of a data group consisting of 118
data packets, wherein, based upon a reference packet (e.g., a
1st packet (or data segment) or 157th packet (or data segment)
after a field synchronization signal), when allocating data
packets to a VSB frame, 37 packets are included before the
reference packet and 81 packets (including the reference
packet) are included afterwards.
[00106] In
other words, with reference to FIG. 5, a field
synchronization signal is placed (or assigned) between M/H
block 2 (B2) and M/H block 3 (B3).
Accordingly, this
indicates that the slot has an off-set of 37 data packets
with respect to the corresponding VSB field.
23
CA 02888511 2015-04-20
[00107]
The size of the data groups, number of hierarchical
regions within the data group, the size of each region, the
number of M/H blocks included in each region, the size of
each M/H block, and so on described above are merely
exemplary.
Therefore, the present invention will not be
limited to the examples described above.
[00108]
FIG. 9 illustrates an exemplary assignment order of
data groups being assigned to one of 5 sub-frames, wherein
the 5 sub-frames configure an M/H frame.
For example, the
method of assigning data groups may be identically applied to
all M/H frames or differently applied to each M/H frame.
Furthermore, the method of assigning data groups may be
identically applied to all sub-frames or differently applied
to each sub-frame.
At this point, when it is assumed that
the data groups are assigned using the same method in all
sub-frames of the corresponding M/H frame, the total number
of data groups being assigned to an M/H frame is equal to a
multiple of '5'.
[00109]
According to the embodiment of the present
invention, a plurality of consecutive data groups is assigned
to be spaced as far apart from one another as possible within
the M/H frame. Thus, the system can be capable of responding
promptly and effectively to any burst error that may occur
within a sub-frame.
24
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[00110]
For example, when it is assumed that 3 data groups
are assigned to a sub-frame, the data groups are assigned to
a 1st slot (Slot #0), a 5th slot (Slot #4), and a 9th slot
(Slot #8) in the sub-frame, respectively. FIG. 9 illustrates
an example of assigning 16 data groups in one sub-frame using
the above-described pattern (or rule).
In other words, each
data group is serially assigned to 16 slots corresponding to
the following numbers: 0, 8, 4, 12, 1, 9, 5, 13, 2, 10, 6, 14,
3, 11, 7, and 15.
[00111]
Equation 1 below shows the above-described rule (or
pattern) for assigning data groups in a sub-frame.
Equation 1
j=(4i+0) mod 16
0=0 if 1<4,
0=2 else if 1<8,
Herein,
0=1 else if 1<12,
0=3 else.
[00112]
Herein, j indicates the slot number within a sub-
frame. The value of j may range from 0 to 15 (i.e., 0_15) .
Also, value of i indicates the data group number. The value
of i may range from 0 to 15 (i.e., 0_15).
[00113]
In the present invention, a collection of data
groups included in an M/H frame will be referred to as a
"parade". Based upon the RS frame mode, the parade transmits
data of at least one specific RS frame.
CA 02888511 2015-04-20
*
[00114]
The mobile service data within one RS frame may be
assigned either to all of regions A/B/C/D within the
corresponding data group, or to at least one of regions
A/B/C/D.
In the embodiment of the present invention, the
mobile service data within one RS frame may be assigned
either to all of regions A/B/C/D, or to at least one of
regions A/B and regions C/D. If the mobile service data are
assigned to the latter case (i.e., one of regions A/B and
regions C/D), the RS frame being assigned to regions A/B and
the RS frame being assigned to regions C/D within the
corresponding data group are different from one another. In
the description of the present invention, the RS frame being
assigned to regions A/B within the corresponding data group
will be referred to as a "primary RS frame", and the RS frame
being assigned to regions C/D within the corresponding data
group will be referred to as a "secondary RS frame", for
simplicity. Also, the primary RS frame and the secondary RS
frame form (or configure) one parade.
More specifically,
when the mobile service data within one RS frame are assigned
either to all of regions A/B/C/D within the corresponding
data group, one parade transmits one RS frame. In this case,
also the RS frame will be referred to as a "primary RS frame".
Conversely, when the mobile service data within one RS frame
are assigned either to at least one of regions A/B and
regions C/D, one parade may transmit up to 2 RS frames.
26
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[00115]
More specifically, the RS frame mode indicates
whether a parade transmits one RS frame, or whether the
parade transmits two RS frames.
[00116] Table 1 below shows an example of the RS frame mode.
Table 1
RS frame
Description
mode (2 bits)
00 There is only one primary RS frame for
all group regions
There are two separate RS frames.
- Primary RS frame for group regions A
01 and B
- Secondary RS frame for group regions
C and D
Reserved
11 Reserved
[00117]
Table 1 illustrates an example of allocating 2 bits
in order to indicate the RS frame mode.
For example,
referring to Table 1, when the RS frame mode value is equal
to '00', this indicates that one parade transmits one RS
frame. And, when the RS frame mode value is equal to '01',
this indicates that one parade transmits two RS frames, i.e.,
the primary RS frame and the secondary RS frame.
More
specifically, when the RS frame mode value is equal to '01',
data of the primary RS frame for regions A/B are assigned and
transmitted to regions A/B of the corresponding data group.
27
CA 02888511 2015-04-20
Similarly, data of the secondary RS frame for regions C/D are
assigned and transmitted to regions C/D of the corresponding
data group.
[00118]
As described in the assignment of data groups, the
parades are also assigned to be spaced as far apart from one
another as possible within the sub-frame.
Thus, the system
can be capable of responding promptly and effectively to any
burst error that may occur within a sub-frame.
[00119]
Furthermore, the method of assigning parades may be
identically applied to all sub-frames or differently applied
to each sub-frame.
According to the embodiment of the
present invention, the parades may be assigned differently
for each M/H frame and identically for all sub-frames within
an M/H frame. More specifically, the M/H frame structure may
vary by M/H frame units.
Thus, an ensemble rate may be
adjusted on a more frequent and flexible basis.
[00120]
FIG. 10 illustrates an example of multiple data
groups of a single parade being assigned (or allocated) to an
M/H frame.
[00121]
More specifically, FIG. 10 illustrates an example
of a plurality of data groups included in a single parade,
wherein the number of data groups included in a sub-frame is
equal to '3', being allocated to an M/H frame. Referring to
FIG. 10, 3 data groups are sequentially assigned to a sub-
frame at a cycle period of 4 slots. Accordingly, when this
28
CA 02888511 2015-04-20
process is equally performed in the 5 sub-frames included in
the corresponding M/H frame, 15 data groups are assigned to a
single M/H frame.
Herein, the 15 data groups correspond to
data groups included in a parade. Therefore, since one sub-
frame is configured of 4 VSB frame, and since 3 data groups
are included in a sub-frame, the data group of the
corresponding parade is not assigned to one of the 4 VSB
frames within a sub-frame.
[00122]
For example, when it is assumed that one parade
transmits one RS frame, and that a RS frame encoder located
in a later block performs RS-encoding on a payload of the
corresponding RS frame, thereby adding 24 bytes of parity
data to the corresponding RS frame payload and transmitting
the processed RS frame, the parity data occupy approximately
11.37% (=24/(187+24)x100) of the total code word length.
Meanwhile, when one sub-frame includes 3 data groups, and
when the data groups included in the parade are assigned, as
shown in FIG. 10, a total of 15 data groups form an RS frame.
Accordingly, even when an error occurs in an entire data
group due to a burst noise within a channel, the percentile
is merely 6.67% (=1/15x100). Therefore, the receiving system
may correct all errors by performing an erasure RS decoding
process. More specifically, when the erasure RS decoding is
performed, a number of channel errors corresponding to the
number of RS parity bytes may be corrected. By doing so, the
29
CA 02888511 2015-04-20
receiving system may correct the error of at least one data
group within one parade.
Thus, the minimum burst noise
length correctable by a RS frame is over 1 VSB frame.
[00123]
Meanwhile, when data groups of a parade are
assigned as described above, either main service data may be
assigned between each data group, or data groups
corresponding to different parades may be assigned between
each data group.
More specifically, data groups
corresponding to multiple parades may be assigned to one M/H
frame.
[00124]
Basically, the method of assigning data groups
corresponding to multiple parades is very similar to the
method of assigning data groups corresponding to a single
parade.
In other words, data groups included in other
parades that are to be assigned to an M/H frame are also
respectively assigned according to a cycle period of 4 slots.
[00125]
At this point, data groups of a different parade
may be sequentially assigned to the respective slots in a
circular method.
Herein, the data groups are assigned to
slots starting from the ones to which data groups of the
previous parade have not yet been assigned.
[00126]
For example, when it is assumed that data groups
corresponding to a parade are assigned as shown in FIG. 10,
data groups corresponding to the next parade may be assigned
to a sub-frame starting either from the 12th slot of a sub-
CA 02888511 2015-04-20
frame. However, this is merely exemplary.
In another
example, the data groups of the next parade may also be
sequentially assigned to a different slot within a sub-frame
at a cycle period of 4 slots starting from the 3rd Slot.
[00127]
FIG. 11 illustrates an example of transmitting 3
parades (Parade #0, Parade #1, and Parade #2) to an M/H frame.
More specifically, FIG. 11 illustrates an example of
transmitting parades included in one of 5 sub-frames, wherein
the 5 sub-frames configure one M/H frame.
[00128]
When the 1st parade (Parade #0) includes 3 data
groups for each sub-frame, the positions of each data groups
within the sub-frames may be obtained by substituting values
'0' to '2' for i in Equation 1. More specifically, the data
groups of the 1st parade (Parade #0) are sequentially assigned
to the 1st, 5th, and 9th Slots (Slot #0, Slot #4, and Slot #8)
within the sub-frame.
Also, when the 2nd parade includes 2
data groups for each sub-frame, the positions of each data
groups within the sub-frames may be obtained by substituting
values '3' and '4' for i in Equation 1.
[00129]
More specifically, the data groups of the 2'd
parade (Parade #1) are sequentially assigned to the 2'd and
12th Slots (Slot #3 and Slot #11) within the sub-frame.
[00130]
Finally, when the 3rd parade includes 2 data groups
for each sub-frame, the positions of each data groups within
the sub-frames may be obtained by substituting values '5' and
31
CA 02888511 2015-04-20
'6' for i in Equation 1. More specifically, the data groups
of the 3rd parade (Parade #2) are sequentially assigned to the
7th and 11th slots (Slot #6 and Slot #10) within the sub-frame.
[00131]
As described above, data groups of multiple parades
may be assigned to a single M/H frame, and, in each sub-frame,
the data groups are serially allocated to a group space
having 4 slots from left to right.
[00132]
Therefore, a number of groups of one parade per
sub-frame (NOG) may correspond to any one integer from '1' to
'8'. Herein, since one M/H frame includes 5 sub-frames, the
total number of data groups within a parade that can be
allocated to an M/H frame may correspond to any one multiple
of '5' ranging from '5' to '40'.
[00133]
FIG. 12 illustrates an example of expanding the
assignment process of 3 parades, shown in FIG. 11, to 5 sub-
frames within an M/H frame.
[00134]
FIG. 13 illustrates a data transmission structure
according to an embodiment of the present invention, wherein
signaling data are included in a data group so as to be
transmitted.
[00135]
As described above, an M/H frame is divided into 5
sub-frames.
Data groups corresponding to a plurality of
parades co-exist in each sub-frame. Herein, the data groups
corresponding to each parade are grouped by M/H frame units,
thereby configuring a single parade.
32
CA 02888511 2015-04-20
[00136] The data structure shown in FIG. 13 includes 3
parades(parade #0, parade #1, parade #2). Also, a
predetermined portion of each data group (i.e., 37 bytes/data
group) is used for delivering (or sending) FIC information
associated with mobile service data, wherein the FIC
information is separately encoded from the RS-encoding
process. The FIC region assigned to each data group consists
of one FIC segments.
[00137] Meanwhile, the concept of an M/H ensemble is applied in
the embodiment of the present invention, thereby defining a
collection (or group) of services. Each M/H ensemble carries
the same QoS and is coded with the same FEC code. Also, each
ensemble has a unique identifier (i.e., ensemble ID) and
corresponds to consecutive RS frames.
[00138] As shown in FIG. 13, the FIC segment corresponding to
each data group described service information of an M/H
ensemble to which the corresponding data group belongs.
[00139]
In other words, the transmitting/receiving system
according to one embodiment of the present invention manages
two data channels.
One data channel is an RS frame data
channel for contents transmission, and the other data channel
is a fast information channel (FIC) for service acquisition.
The present invention is intended that mapping information
between ensemble and mobile service is signaled using FIC
chunk, which is split in a FIC segment unit and then
33
CA 02888511 2015-04-20
transmitted through the FIG, whereby the receiving system can
perform fast service acquisition.
General Description of the Transmitting System
[00140]
FIG. 14 illustrates a block diagram showing a
general structure of a digital broadcast transmitting system
according to an embodiment of the present invention.
[00141]
Herein, the digital broadcast transmitting includes
a service multiplexer 100 and a transmitter 200. Herein, the
service multiplexer 100 is located in the studio of each
broadcast station, and the transmitter 200 is located in a
site placed at a predetermined distance from the studio. The
transmitter 200 may be located in a plurality of different
locations. Also, for example, the plurality of transmitters
may share the same frequency. And, in this case, the
plurality of transmitters receives the same signal.
This
corresponds to data transmission using Single Frequency
Network (SFN). Accordingly, in the receiving system, a
channel equalizer may compensate signal distortion, which is
caused by a reflected wave, so as to recover the original
signal.
In another example, the plurality of transmitters
may have different frequencies with respect to the same
channel. This corresponds to data transmission using Multi
Frequency Network (MFN).
34
CA 02888511 2015-04-20
[00142] A
variety of methods may be used for data
communication each of the transmitters, which are located in
remote positions, and the service multiplexer.
For example,
an interface standard such as a synchronous serial interface
for transport of MPEG-2 data (SMPTE-310M). In the SMPTE-310M
interface standard, a constant data rate is decided as an
output data rate of the service multiplexer. For example, in
case of the 8VSB mode, the output data rate is 19.39 Mbps,
and, in case of the 16VSB mode, the output data rate is 38.78
Mbps. Furthermore, in the conventional 8VSB mode transmitting
system, a transport stream (TS) packet having a data rate of
approximately 19.39 Mbps may be transmitted through a single
physical channel. Also, in the transmitting system according
to the present invention provided with backward compatibility
with the conventional transmitting system, additional
encoding is performed on the mobile service data. Thereafter,
the additionally encoded mobile service data are multiplexed
with the main service data to a TS packet form, which is then
transmitted. At this point, the data rate of the multiplexed
IS packet is approximately 19.39 Mbps.
[00143]
At this point, the service multiplexer 100 receives
at least one type of main service data and table information
(e.g., PSI/PSIP table data) for each main service and
encapsulates the received data into a transport stream (TS)
packet.
CA 02888511 2015-04-20
. ,
[00144] Also, according to an embodiment of the present
invention, the service multiplexer 100 receives at least one
type of mobile service data and table information (e.g.,
PSI/PSIP table data) for each mobile service and encapsulates
the received data and table information into mobile service
data packets of a transport stream (TS) packet type.
[00145] According to another embodiment of the present
invention, the service multiplexer 100 receives a RS frame
(or RS frame payload), which is configured of at least one
type of mobile service data and table information for each
mobile service, and encapsulates the received RS frame data
into mobile service data packets of a transport stream (TS)
packet format.
[00146] And, the service multiplexer 100 multiplexes the
encapsulated TS packets for main service and the encapsulated
TS packets for mobile service based upon a predetermined
multiplexing rule, thereby outputting the multiplexed TS
packets to the transmitter 200.
[00147] At this point, the RS frame payload (or RS frame)
has the size of N (row) x 187 (column), as shown in FIG. 15.
Herein, N represents the length of a row (i.e., number of
columns), and 187 corresponds to the length of a column (i.e.,
number of rows.
[00148] In the present invention, for convenience of
description, each row of the N bytes will be referred to as
36
CA 02888511 2015-04-20
M/H service data packet (or M/H TP packet). The M/H service
data packet includes M/H header of 2 bytes, a stuffing region
of k bytes, and M/H payload of N-2-k bytes. At this time, k
has a value of 0 or a value greater than 0. In this case, the
M/H header of 2 bytes is only one example, and corresponding
bytes can be varied depending on a designer. Accordingly, the
present invention will not be limited to such example.
[00149] At this time, as the M/H service data packet
includes M/H header, the M/H header may not reach N bytes.
[00150] In this case, stuffing bytes can be assigned to the
remaining payload part of the corresponding M/H service data
packet. For example, after program table information is
assigned to one M/H service data packet, if the length of the
M/H service data packet is N-20 bytes including the M/H
header, the stuffing bytes can be assigned to the remaining
20 bytes. In this case, the value k becomes 20, and the M/H
payload region within the corresponding M/H service data
packet includes N-2-20 bytes.
[00151] The RS frame payload is generated by collecting
signaling table information corresponding to one or more
mobile services and/or IP datagram of the mobile service data.
For example, signaling table information for two kinds of
mobile services called news (for example, IP datagram for
mobile service 1) and the stocks (for example, IP datagram
37
CA 02888511 2015-04-20
, .
,
for mobile service 2) and IP datagram of mobile service data
can be included in one RS frame payload.
[00152] More specifically, in the transmitting system (e.g.,
mobile broadcast station), the mobile service data (e.g., A/V
steaming) are packetized based upon a real time protocol
(RTP) method.
The RTP packet is then packetized once again
based upon a user datagram protocol (UDP) method. Thereafter,
the RTP/UDP packet is in turn packetized based upon an IP
method, thereby being packetized into RTP/UDP/IP packet data.
In the description of the present invention, the packetized
RTP/UDP/IP packet data will be referred to as an IP datagram
for simplicity.
[00153]
Furthermore, service information for receiving
mobile services may be provided in the form of a signaling
table. And, a service signaling channel transmitting such
signaling table is packetized based upon a UDP method. And,
the packetized UDP data are then packetized based upon an IP
method, thereby being packetized into UDP/IP data.
In the
description of the present invention, the packetized UDP/IP
packet data will also be referred to as an IP datagram for
simplicity.
According to an embodiment of the present
invention, the service signaling channel is encapsulated into
an IP datagram having a well-known destination IP address and
a well-known destination UDP port number.
38
CA 02888511 2015-04-20
[00154]
More specifically, one RS frame payload includes an
IP datagram of mobile service data for at least one or more
mobile services and an IP datagram of a service signaling
channel for receiving the mobile service data.
[00155]
According to the embodiment of the present
invention, among a service map table (SMT), a guide access
table (GAT), a cell information table (CIT), a service
labeling table (SLT), and a rating region table (RRT), the
present invention transmits at least one signaling table
through the service signaling channel. Herein, the signaling
tables presented in the embodiment of the present invention
are merely examples for facilitating the understanding of the
present invention.
Therefore, the present invention is not
limited only to the exemplary signaling tables that can be
transmitted through the service signaling channel.
[00156]
The SMT provides signaling information on ensemble
levels. Also, each SMT provides IP access information for
each mobile service belonging to the corresponding ensemble
including each SMT. Furthermore, the SMT provides IP stream
component level information required for the corresponding
mobile service.
[00157]
The RRT transmits information on region and
consultation organs for program ratings. More specifically,
the RRT provides content advisory rating information.
39
CA 02888511 2015-04-20
,
[00158]
The GAT provides information on SG providers, which
transmit the service guides. Also, the GAT provides service
guide bootstrapping information required for accessing the SG.
The CIT provides channel information of each cell, which
corresponds to the frequency domain of a broadcast signal.
Herein, a cell refers to a scope affected (or influenced) by
a transmitter based upon a physical frequency in a multi-
frequency network (MFN) environment (or condition).
More
specifically, the CIT provides information on a carrier wave
frequency of an adjacent cell in the current transmitter (or
transmitting system).
Therefore, based upon the CIT
information, a receiver (or receiving system) can travel from
one transmitter's (or exciter's) coverage area to another.
[00159]
The SLT provides minimum required information for
an exclusive usage of a channel scan process.
More
specifically, according to the embodiment of the present
invention, other than the SMT, by using the SLT for the
exclusive usage of the channel scan process, so as to
configure a set of minimum information for the channel scan
process, the channel scanning speed may be increased.
[00160]
According to an embodiment of the present invention,
each signaling table is divided into at least one section.
Then, each section is encapsulated to a UDP/IP header,
thereby being transmitted through the service signaling
channel.
In this case, the number of UDP/IP packets being
CA 02888511 2015-04-20
. .
transmitted through the service signaling channel may vary
based upon the number of signaling tables being transmitted
through the service signaling channel and the number of
sections in each signaling table.
[00161] At this point, all UDP/IP packets transmitted
through the service signaling channel have the same number of
well-known target IP addresses and well-known target UDP port
numbers. For example, when it is assumed that the SMT, RRT,
and GAT are transmitted through the service signaling channel,
the target IP address and target UDP port number of all
UDP/IP packets transmitting the SMT, RRT, and GAT are
identical to one another. Furthermore, the target IP address
and the target UDP port number respectively correspond to
well-known values, i.e., values pre-known by the receiving
system based upon an agreement between the receiving system
and the transmitting system.
[00162] Therefore, the identification of each signaling
table included in the service signaling data is performed by
a table identifier. The table identifier may correspond to a
table id field existing in the corresponding signaling table
or in the header of the corresponding signaling table section.
And, when required, identification may be performed by
further referring to a table _ id _extension field.
[00163] FIG. 16 is a diagram illustrating examples of
fields allocated to the M/H header region within the M/H
41
CA 02888511 2015-04-20
service data packet according to the present invention.
Examples of the fields include type_indicator field,
error indicator field, stuff indicator field, and pointer
field.
[00164] The type_indicator field can allocate 3 bits, for
example, and represents a type of data allocated to payload
within the corresponding M/H service data packet. In other
words, the type_indicator field indicates whether data of the
payload is IP datagram or program table information. At this
time, each data type constitutes one logical channel. In the
logical channel which transmits the IP datagram, several
mobile services are multiplexed and then transmitted. Each
mobile service undergoes demultiplexing in the IP layer.
[00165] The error indicator field can allocate 1 bit, for
example, and represents whether the corresponding M/H service
data packet has an error. For example, if the error_indicator
field has a value of 0, it means that there is no error in
the corresponding M/H service data packet. If the
error indicator field has a value of 1, it means that there
may be an error in the corresponding M/H service data packet.
According to an embodiment of the present invention, a value
of zero are indicated and transmitted on all error indicator
fields within the RS frame.
[00166] The stuff indicator field can allocate 1 bit, for
example, and represents whether stuffing byte exists in
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CA 02888511 2015-04-20
payload of the corresponding M/H service data packet. For
example, if the stuff indicator field has a value of 0, it
means that there is no stuffing byte in the corresponding M/H
service data packet. If the stuff_indicator field has a value
of 1, it means that stuffing byte exists in the corresponding
M/H service data packet.
[00167] The pointer field can allocate 11 bits, for example,
and represents position information where new data (i.e., new
signaling information or new IP datagram) starts in the
corresponding M/H service data packet.
[00168] For example, if IP datagram for mobile service 1
and IP datagram for mobile service 2 are allocated to the
first M/H service data packet within the RS frame payload as
illustrated in FIG. 15, the pointer field value represents
the start position of the IP datagram for mobile service 2
within the M/H service data packet.
[00169] Also, if there is no new data in the corresponding
M/H service data packet, the corresponding field value is
expressed as a maximum value exemplarily. According to the
embodiment of the present invention, since 11 bits are
allocated to the pointer field, if 2047 is expressed as the
pointer field value, it means that there is no new data in
the packet. The point where the pointer field value is 0 can
be varied depending on the type_indicator field value and the
stuff indicator field value.
43
CA 02888511 2015-04-20
. .
[00170] It is to be understood that the order, the position,
and the meaning of the fields allocated to the header within
the M/H service data packet illustrated in FIG. 16 are
exemplarily illustrated for understanding of the present
invention. Since the order, the position and the meaning of
the fields allocated to the header within the M/H service
data packet and the number of additionally allocated fields
can easily be modified by those skilled in the art, the
present invention will not be limited to the above example.
[00171] FIG. 17(a) and FIG. 17(b) illustrate another
examples of RS frame payload according to the present
invention. FIG. 17(a) illustrates an example of primary RS
frame payload to be allocated to regions A/B within the data
group, and FIG. 17(b) illustrates an example of secondary RS
frame payload to be allocated to regions C/D within the data
group.
[00172] In FIG. 17(a) and FIG. 17(b), a column length (i.e.,
the number of rows) of the RS frame payload to be allocated
to the regions A/B and a column length (i.e., the number of
rows) of the RS frame payload to be allocated to the regions
C/D are 187 equally. However, row lengths (i.e, the number of
columns) may be different from each other.
[00173] According to the embodiment of the present
invention, when the row length of the primary RS frame
payload to be allocated to the regions A/B within the data
44
CA 02888511 2015-04-20
group is Ni bytes and the row length of the secondary RS
frame payload to be allocated to the regions C/D within the
data group is N2 bytes, a condition of N1>N2 is satisfied. In
this case, Ni and N2 can be varied depending on the
transmission parameter or a region of the data group, to
which the corresponding RS frame payload will be transmitted.
[00174] For convenience of the description, each row of the
Ni and N2 bytes will be referred to as the M/H service data
packet. The M/H service data packet within the RS frame
payload to be allocated to the regions A/B within the data
group can be comprised of M/H header of 2 bytes, a stuffing
region of k bytes, and M/H payload of N1-2-k bytes. At this
time, k has a value of 0 or a value greater than 0. Also, the
M/H service data packet within the RS frame payload to be
allocated to the regions C/D within the data group can be
comprised of M/H header of 2 bytes, a stuffing region of k
bytes, and M/H payload of N2-2-k bytes. At this time, k has a
value of 0 or a value greater than 0.
[00175] In the present invention, the primary RS frame
payload for the regions A/B within the data group and the
secondary RS frame payload for the regions C/D within the
data group can include at least one of IP datagrams of
signaling table information and mobile service data. Also,
one RS frame payload can include IP datagram corresponding to
one or more mobile services.
CA 02888511 2015-04-20
[00176]
Corresponding parts of FIG. 15 can be applied to
the other parts, which are not described in FIG. 17(a) and
FIG. 17(b).
[00177]
Meanwhile, the value of N, which corresponds to the
number of columns within an RS frame payload, can be decided
according to Equation 2.
Equation 2
N =[5 x NoG x PL
2
187 + P
[00178]
Herein, NoG indicates the number of data groups
assigned to a sub-frame.
PL represents the number of SCCC
payload data bytes assigned to a data group.
And, P
signifies the number of RS parity data bytes added to each
column of the RS frame payload. Finally,
is the greatest
integer that is equal to or smaller than X.
[00179]
More specifically, in Equation 2, PL corresponds to
the length of an RS frame portion.
The value of PL is
equivalent to the number of SCCC payload data bytes that are
assigned to the corresponding data group. Herein, the value
of PL may vary depending upon the RS frame mode, SCCC block
mode, and SCCC outer code mode.
Table 2 to Table 5 below
respectively show examples of PL values, which vary in
accordance with the RS frame mode, SCCC.block mode, and SCCC
46
CA 02888511 2015-04-20
, .
outer code mode. The SCCC block mode and the SCCC outer code
mode will be described in detail in a later process.
Table 2
SCCC outer code mode PL
for for for for
Region A Region B Region C Region D
00 00 00 00 9624
00 00 00 01 9372
00 00 01 00 8886
00 00 01 01 8634
00 01 00 00 8403
00 01 00 01 8151
00 01 01 00 7665
00 01 01 01 7413
01 00 00 00 7023
01 00 00 01 6771
01 00 01 00 6285
01 00 01 01 6033
'
01 01 00 00 5802
01 01 00 01 5550
01 01 01 I 00 5064
I
01 01 01 1 01 4812
I
,
Reserv
Others ed
[00180] Table 2 shows an example of the PL values for each
data group within an RS frame, wherein each PL value varies
depending upon the SCCC outer code mode, when the RS frame
47
CA 02888511 2015-04-20
mode value is equal to '00', and when the SCCC block mode
value is equal to '00'. For example, when it is assumed that
each SCCC outer code mode value of regions A/B/C/D within the
data group is equal to '00' (i.e., the block processor 302 of
a later block performs encoding at a coding rate of 1/2), the
PL value within each data group of the corresponding RS frame
may be equal to 9624 bytes. More specifically, 9624 bytes of
mobile service data within one RS frame may be assigned to
regions A/B/C/D of the corresponding data group.
Table 3
SCCC outer code mode PL
00 9624
01 4812
Reserv
Others
ed
[00181] Table 3 shows an example of the PL values for each
data group within an RS frame, wherein each PL value varies
depending upon the SCCC outer code mode, when the RS frame
mode value is equal to '00', and when the SCCC block mode
value is equal to '01'.
Table 4
SCCC outer code mode PL
For Region A for Region B
48
CA 02888511 2015-04-20
00 00 7644
00 01 6423
01 00 5043
01 01 3822
Reserv
Others
ed
[00182]
Table 4 shows an example of the PL values for each
data group within a primary RS frame, wherein each PL value
varies depending upon the SCCC outer code mode, when the RS
frame mode value is equal to '01', and when the SCCC block
mode value is equal to '00'.
For example, when each SCCC
outer code mode value of regions A/B is equal to '00', 7644
bytes of mobile service data within a primary RS frame may be
assigned to regions A/B of the corresponding data group.
Table 5
SCCC outer code mode PL
For Region C for Region D
00 00 1980
00 01 1728
01 00 1242
01 01 990
Reserv
Others
ed
[00183]
Table 5 shows an example of the PL values for each
data group within a secondary RS frame, wherein each PL value
49
CA 02888511 2015-04-20
varies depending upon the SCCC outer code mode, when the RS
frame mode value is equal to '01', and when the SCCC block
mode value is equal to '00'.
For example, when each SCCC
outer code mode value of regions C/D is equal to '00', 1980
bytes of mobile service data within a secondary RS frame may
be assigned to regions C/D of the corresponding data group.
Service Multiplexer
[00184]
FIG. 18 illustrates a block diagram showing an
example of the service multiplexer. The service multiplexer
includes a controller 110 for controlling the overall
operations of the service multiplexer, a table information
generator 120 for the main service, a null packet generator
130, an ON packet encapsulator 140, a mobile service
multiplexer 150, and a transport multiplexer 160.
[00185]
The transport multiplexer 160 may include a main
service multiplexer 161 and a transport stream (TS) packet
multiplexer 162.
[00186]
Referring to FIG. 18, at least one type of
compression-encoded main service data and table data
generated from the table information generator 120 for the
main services are inputted to the main service multiplexer
161 of the transport multiplexer 160. According to the
embodiment of the present invention, the table information
CA 02888511 2015-04-20
generator 120 generates PSI/PSIP table data, which is
configured in the form of an MPEG-2 private section.
[00187]
The main service multiplexer 161 respectively
encapsulates each of the main service data and the PSI/PSIP
table data, which are being inputted, to MPEG-2 TS packet
formats, thereby multiplexing the encapsulated TS packets and
outputting the multiplexed packets to the TS packet
multiplexer 162.
Herein, the data packet being outputted
from the main service multiplexer 161 will hereinafter be
referred to as a main service data packet for simplicity.
[00188]
The mobile service multiplexer 150 receives and
respectively encapsulates at least one type of compression-
encoded mobile service data and the table information (e.g.,
PSI/PSIP table data) for mobile services to MPEG-2 TS packet
formats.
Then, the mobile service multiplexer 150
multiplexes the encapsulated TS packets, thereby outputting
the multiplexed packets to the TS packet multiplexer 162.
Hereinafter, the data packet being outputted from the mobile
service multiplexer 150 will be referred to as a mobile
service data packet for simplicity.
[00189]
Alternatively, the mobile service multiplexer 150
receives and encapsulates an RS frame payload, which is
generated by using at least one type of compression-encoded
mobile service data and the signaling table information for
mobile services, to MPEG-2 TS packet formats.
Then, the
51
CA 02888511 2015-04-20
. .
mobile service multiplexer 150 multiplexes the encapsulated
TS packets, thereby outputting the multiplexed packets to the
TS packet multiplexer 162.
Hereinafter, the data packet
being outputted from the mobile service multiplexer 150 will
be referred to as a mobile service data packet for simplicity.
[00190] According to an embodiment of the present invention,
the mobile service multiplexer 150 encapsulates an RS frame
payload, which is inputted in any one of the formats shown in
FIG. 15, FIG. 17(a), or FIG. 17(b), to a TS packet format.
[00191]
At this point, the transmitter 200 requires
identification information in order to identify and process
the main service data packet and the mobile service data
packet.
Herein, the identification information may use
values pre-decided in accordance with an agreement between
the transmitting system and the receiving system, or may be
configured of a separate set of data, or may modify
predetermined location value with in the corresponding data
packet.
[00192]
As an example of the present invention, a different
packet identifier (PIG) may be assigned to identify each of
the main service data packet and the mobile service data
packet. More specifically, by assigning a PIG, which does not
use for the main service data packet, to the mobile service
data packet, the transmitter 200 refers to a PIG of data
52
CA 02888511 2015-04-20
=
packet inputted, thereby can identify each of the main
service data packet and the mobile service data packet.
[00193]
In another example, by modifying a synchronization
data byte within a header of the mobile service data, the
service data packet may be identified by using the
synchronization data byte value of the corresponding service
data packet.
For example, the synchronization byte of the
main service data packet directly outputs the value decided
by the ISO/IEC 13818-1 standard (i.e., 0x47) without any
modification. The synchronization byte of the mobile service
data packet modifies and outputs the value, thereby
identifying the main service data packet and the mobile
service data packet. Conversely, the synchronization byte of
the main service data packet is modified and outputted,
whereas the synchronization byte of the mobile service data
packet is directly outputted without being modified, thereby
enabling the main service data packet and the mobile service
data packet to be identified.
[00194] A
plurality of methods may be applied in the method
of modifying the synchronization byte. For example, each bit
of the synchronization byte may be inversed, or only a
portion of the synchronization byte may be inversed.
[00195]
As described above, any type of identification
information may be used to identify the main service data
packet and the mobile service data packet.
Therefore, the
53
CA 02888511 2015-04-20
scope of the present invention is not limited only to the
example set forth in the description of the present invention.
[00196]
Meanwhile, a transport multiplexer used in the
conventional digital broadcasting system may be used as the
transport multiplexer 160 according to the present invention.
More specifically, in order to multiplex the mobile service
data and the main service data and to transmit the
multiplexed data, the data rate of the main service is
limited to a data rate of (19.39-K) Mbps.
Then, K Mbps,
which corresponds to the remaining data rate, is assigned as
the data rate of the mobile service.
Thus, the transport
multiplexer which is already being used may be used as it is
without any modification.
[00197]
Herein, the transport multiplexer 160 multiplexes
the main service data packet being outputted from the main
service multiplexer 161 and the mobile service data packet
being outputted from the mobile service multiplexer 150.
Thereafter, the transport multiplexer 160 transmits the
multiplexed data packets to the transmitter 200.
[00198]
However, in some cases, the output data rate of the
mobile service multiplexer 150 may not be equal to K Mbps.
For example, when the service multiplexer 100 assigns K Mbps
of the 19.39 Mbps to the mobile service data, and when the
remaining (19.39-K) Mbps is, therefore, assigned to the main
service data, the data rate of the mobile service data that
54
CA 02888511 2015-04-20
=
are multiplexed by the service multiplexer 100 actually
becomes lower than K Mbps. This is because, in case of the
mobile service data, the pre-processor of the transmitting
system performs additional encoding, thereby increasing the
amount of data.
Eventually, the data rate of the mobile
service data, which may be transmitted from the service
multiplexer 100, becomes smaller than K Mbps.
[00199]
For example, since the pre-processor of the
transmitter performs an encoding process on the mobile
service data at a coding rate of at least 1/2, the amount of
the data outputted from the pre-processor is increased to
more than twice the amount of the data initially inputted to
the pre-processor.
Therefore, the sum of the data rate of
the main service data and the data rate of the mobile service
data, both being multiplexed by the service multiplexer 100,
becomes either equal to or smaller than 19.39 Mbps.
[00200]
In order to set the final output data rate of the
mobile service multiplexer 150 to K Mbps, the service
multiplexer 100 of the present invention may perform various
exemplary operations.
[00201] According to an embodiment of the present invention,
the null packet generator 130 may generate a null data packet,
which is then outputted to the mobile service multiplexer 150.
Thereafter, the mobile service multiplexer 150 may multiplex
CA 02888511 2015-04-20
the null data packet and the mobile service data packets, so
as to set the output data rate to K Mbps.
[00202]
At this point, the null data packet is transmitted
to the transmitter 200, thereby being discarded.
More
specifically, the null data packet is not transmitted to the
receiving system.
In order to do so, identification
information for identifying the null data is also required.
Herein, the identification information for identifying the
null data may also use a value pre-decided based upon an
agreement between the transmitting system and the receiving
system and may also be configured of a separate set of data.
And, the identification information for identifying the null
data may also change a predetermined position value within
the null data packet and use the changed value. For example,
the null packet generator 130 may modify (or change) a
synchronization byte value within the header of the null data
packet, thereby using the changed value as the identification
information.
Alternatively, the transport error indicator
flag may be set to '1', thereby being used as the
identification information. According to the embodiment of
the present invention, the transport_error_indicator flag
within the header of the null data packet is used as the
identification information for identifying the null data
packet.
In this case, the transport error indicator flag of
the null data packet is set to '1', and the
56
CA 02888511 2015-04-20
transport_error indicator flag for each of the other
remaining data packets is reset to '0', so that the null data
packet can be identified (or distinguished).
[00203]
More specifically, when the null packet generator
130 generated a null data packet, and if, among the fields
included in the header of the null data packet, the
transport error indicator flag is set to '1' and then
transmitted, the transmitter 200 may identify and discard the
null data packet corresponding to
the
transport_error indicator flag.
[00204]
Herein, any value that can identify the null data
packet may be used as the identification information for
identifying the null data packet.
Therefore, the present
invention will not be limited only to the example proposed in
the description of the present invention.
[00205]
As another example of setting (or matching) the
final output data rate of the mobile service multiplexer 150
to K Mbps, an operations and maintenance (OM) packet (also
referred to as OMP) may be used.
In this case, the mobile
service multiplexer 150 may multiplex the mobile service data
packet, the null data packet, and the OM packet, so as to set
the output data rate to K Mbps.
[00206]
Meanwhile, signaling data, such as transmission
parameters, are required for enabling the transmitter 200 to
process the mobile service data.
57
CA 02888511 2015-04-20
[00207] According to an embodiment of the present invention,
the transmission parameter is inserted in the payload region
of the ON packet, thereby being transmitted to the
transmitter.
[00208]
At this point, in order to enable the transmitter
200 to identify the insertion of the transmission parameter
in the ON packet, identification information that can
identify the insertion of the transmission parameter in the
type field of the corresponding ON packet (i.e., OM_type
field).
[00209]
More specifically, an operations and maintenance
packet (OMP) is defined for the purpose of operating and
managing the transmitting system.
For example, the OMP is
configured in an MPEG-2 TS packet format, and the value of
its respective PID is equal to '0x1FFA'. The OMP consists of
a 4-byte header and a 184-byte payload. Among the 184 bytes,
the first byte corresponds to the OM type field indicating
the type of the corresponding ON packet (OMP).
And, the
remaining 183 bytes correspond to an OM_payload field,
wherein actual data are inserted.
[00210]
According to the present invention, among the
reserved field values of the OM_type field, a pre-arranged
value is used, thereby being capable of indicating that a
transmission parameter has been inserted in the corresponding
ON packet.
Thereafter, the transmitter 200 may locate (or
58
CA 02888511 2015-04-20
identify) the corresponding OMP by referring to the
respective PID.
Subsequently, by parsing the ON type field
within the OMP, the transmitter 200 may be able to know (or
recognize) whether or not a transmission parameter has been
inserted in the corresponding ON packet.
[00211]
The transmission parameters that can be transmitted
to the ON packet include M/H frame information (e.g., M/H
frame index), FIC information (e.g., next FIC version number),
parade information (e.g., number _ of _parades,
parade id,
parade_repetition cycle, and ensemble id), group information
(e.g., number _ of _group and start
group number), SCCC
information (e.g., SCCC block mode and SCCC outer code mode),
RS frame information (e.g., RS Frame
mode and
RS frame continuity counter), RS encoding information (e.g.,
RS code mode), and so on.
[00212]
At this point, the ON packet in which the
transmission parameter is inserted may be periodically
generated by a constant cycle, so as to be multiplexed with
the mobile service data packet.
[00213]
The multiplexing rules and the generation of null
data packets of the mobile service multiplexer 150, the main
service multiplexer 161, and the TS packet multiplexer 160
are controlled by the controller 110.
[00214]
The TS packet multiplexer 162 multiplexes a data
packet being outputted from the main service multiplexer 161
59
CA 02888511 2015-04-20
at (19.39-K) Mbps with a data packet being outputted from the
mobile service multiplexer 150 at K Mbps. Thereafter, the TS
packet multiplexer 162 transmits the multiplexed data packet
to the transmitter 200 at a data rate of 19.39 Mbps.
Transmitter
[00215]
FIG. 19 illustrates a block diagram showing an
example of the transmitter 200 according to an embodiment of
the present invention. Herein, the transmitter 200 includes
a controller 201, a demultiplexer 210, a packet jitter
mitigator 220, a pre-processor 230, a packet multiplexer 240,
a post-processor 250, a synchronization (sync) multiplexer
260, and a transmission unit 270.
[00216]
Herein, when a data packet is received from the
service multiplexer 100, the demultiplexer 210 should
identify whether the received data packet corresponds to a
main service data packet, a mobile service data packet, a
null data packet, or an OM packet.
[00217]
For example, the demultiplexer 210 uses the PID
within the received data packet so as to identify the main
service data packet, the mobile service data packet, and the
null data packet.
Then, the demultiplexer 210 uses a
transport error_indicator field to identify the null data
packet.
[00218]
If an ON packet is included in the received data
CA 02888511 2015-04-20
packet, the ON packet may identify using the PID within the
received data packet. And by using the ON type field included
in the identified ON packet, the demultiplexer 210 may be
able to know whether or not a transmission parameter is
included in the payload region of the corresponding ON packet
and, then, received.
[00219]
The main service data packet identified by the
demultiplexer 210 is outputted to the packet jitter mitigator
220, the mobile service data packet is outputted to the pre-
processor 230, and the null data packet is discarded. If the
transmission parameter is included in the ON packet, the
corresponding transmission parameter is extracted, so as to
be outputted to the corresponding blocks. Thereafter, the ON
packet is discarded. According to an embodiment of the
present invention, the transmission parameter extracted from
the ON packet is outputted to the corresponding blocks
through the controller 201.
[00220]
The pre-processor 230 performs an additional
encoding process of the mobile service data included in the
service data packet, which is demultiplexed and outputted
from the demultiplexer 210.
The pre-processor 230 also
performs a process of configuring a data group so that the
data group may be positioned at a specific place in
accordance with the purpose of the data, which are to be
transmitted on a transmission frame. This is to enable the
61
CA 02888511 2015-04-20
mobile service data to respond swiftly and strongly against
noise and channel changes.
[00221]
According to one embodiment of the present
invention, RS frame payload of FIG. 15 (or (a) and (b) of FIG.
17) is encapsulated into TS packet by the service multiplexer
100 and transmitted to the transmitter. In this case, mobile
service data within the mobile service data packet become a
part of data of the RS frame payload. In the present
invention, for convenience of description, M/H header data of
2 bytes of each M/H service data packet, stuffing data of k
bytes, and M/H payload data of N-2-k bytes will be referred
to as mobile service data. According to one embodiment of the
present invention, the M/H payload data are signaling table
and/or IP datagram of mobile service data.
[00222]
The pre-processor 230 may also refer to the
transmission parameter extracted in the ON packet when
performing the additional encoding process. Also, the pre-
processor 230 groups a plurality of mobile service data
packets to configure a data group.
Thereafter, known data,
mobile service data, RS parity data, and MPEG header are
allocated to pre-determined regions within the data group.
Pre-processor within Transmitter
[00223]
FIG. 20 illustrates a block diagram showing the
structure of a pre-processor 230 according to the present
62
CA 02888511 2015-04-20
invention.
Herein, the pre-processor 230 includes an M/H
frame encoder 301, a block processor 302, a group formatter
303, a signaling encoder 304, and a packet formatter 305.
[00224]
The M/H frame encoder 301, which is included in the
pre-processor 230 having the above-described structure, data-
randomizes the mobile service data that are inputted to the
demultiplexer 210, thereby forming at least one RS frame
belonging to an ensemble.
[00225]
The M/H frame encoder 301 may include at least one
RS frame encoder. More specifically, RS frame encoders may
be provided in parallel, wherein the number of RS frame
encoders is equal to the number of parades within the M/H
frame.
As described above, the M/H frame is a basic time
cycle period for transmitting at least one parade.
Also,
each parade consists of one or two RS frames.
[00226]
FIG. 21 illustrates a conceptual block diagram of
the M/H frame encoder 301 according to an embodiment of the
present invention.
The M/H frame encoder 301 includes an
input demultiplexer (DEMUX) 309, M number of RS frame
encoders 310 to 31M-1, and an output multiplexer (MUX) 320.
Herein, M represent the number of parades included in one M/H
frame.
[00227]
The demultiplexer 309 output the inputted mobile
service data packet to a corresponding RS frame encoder among
M number of RS frame encoders in ensemble units.
63
' CA 02888511 2015-04-20
. .
[00228] According to an embodiment of the present invention,
each RS frame encoder forms an RS frame payload using mobile
service data inputted and performs an error correction
encoding process in RS frame payload units, thereby forming
an RS frame. Also, each RS frame encoder divides the error-
correction-encoded RS frame into a plurality of portions, in
order to assign the error-correction-encoded RS frame data to
a plurality of data groups. Based upon the RS frame mode of
Table 1, data within one RS frame may be assigned either to
all of regions A/B/C/D within multiple data groups, or to at
least one of regions A/B and regions C/D within multiple data
groups.
[00229] When the RS frame mode value is equal to '01', i.e.,
when the data of the primary RS frame are assigned to regions
A/B of the corresponding data group and data of the secondary
RS frame are assigned to regions C/D of the corresponding
data group, each RS frame encoder creates a primary RS frame
and a secondary RS frame for each parade. Conversely, when
the RS frame mode value is equal to '00', when the data of
the primary RS frame are assigned to all of regions A/B/C/D,
each RS frame encoder creates a RS frame (i.e., a primary RS
frame) for each parade.
[00230] Also, each RS frame encoder divides each RS frame
into several portions. Each portion of the RS frame is
equivalent to a data amount that can be transmitted by a data
64
CA 02888511 2015-04-20
group. The output multiplexer (MUX) 320 multiplexes portions
within M number of RS frame encoders 310 to 310M-1 are
multiplexed and then outputted to the block processor 302.
[00231]
For example, if one parade transmits two RS frames,
portions of primary RS frames within M number of RS frame
encoders 310 to 310M-1 are multiplexed and outputted.
Thereafter, portions of secondary RS frames within M number
of RS frame encoders 310 to 310M-1 are multiplexed and
transmitted.
[00232]
The input demultiplexer (DEMUX) 309 and the output
multiplexer (MUX) 320 operate based upon the control of the
controller 201. The controller 201 may provide necessary (or
required) FEC modes to each RS frame encoder. The FEC mode
includes the RS code mode, which will be described in detail
in a later process.
[00233]
FIG. 22 illustrates a detailed block diagram of an
RS frame encoder among a plurality of RS frame encoders
within an M/H frame encoder.
[00234]
One RS frame encoder may include a primary encoder
410 and a secondary encoder 420.
Herein, the secondary
encoder 420 may or may not operate based upon the RS frame
mode. For example, when the RS frame mode value is equal to
'00', as shown in Table 1, the secondary encoder 420 does not
operate.
CA 02888511 2015-04-20
[00235]
The primary encoder 410 may include a data
randomizer 411, a Reed-Solomon-cyclic redundancy check (RS-
CRC) encoder (412), and a RS frame divider 413.
And, the
secondary encoder 420 may also include a data randomizer 421,
a RS-CRC encoder (422), and a RS frame divider 423.
[00236]
More specifically, the data randomizer 411 of the
primary encoder 410 receives mobile service data of a primary
RS frame payload belonging to a primary ensemble outputted
from the output demultiplexer (DEMUX) 309.
Then, after
randomizing the received mobile service data, the data
randomizer 411 outputs the randomized data to the RS-CRC
encoder 412.
[00237]
The RS-CRC encoder 412 forms an RS frame payload
belonging to the randomized primary ensemble, and performs
forward error collection (FEC)-encoding in the RS frame
payload unit using at least one of a Reed-Solomon (RS) code
and a cyclic redundancy check (CRC) code. The RS-CRC encoder
412 outputs the FEC-encoded RS frame to the RS frame divider
413.
[00238]
The RS-CRC encoder 412 groups a plurality of mobile
service data that is randomized and inputted, so as to form a
RS frame payload. Then, the RS-CRC encoder 412 performs at
least one of an error correction encoding process and an
error detection encoding process in RS frame payload units,
thereby forming an RS frame. Accordingly, robustness may be
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CA 02888511 2015-04-20
provided to the mobile service data, thereby scattering group
error that may occur during changes in a frequency
environment, thereby enabling the mobile service data to
respond to the frequency environment, which is extremely
vulnerable and liable to frequent changes. Also, the RS-CRC
encoder 412 groups a plurality of RS frame so as to create a
super frame, thereby performing a row permutation process in
super frame units. The row permutation process may also be
referred to as a "row interleaving process".
Hereinafter,
the process will be referred to as "row permutation" for
simplicity. In the present invention, the row permutation
process is optional.
[00239]
More specifically, when the RS-CRC encoder 412
performs the process of permuting each row of the super frame
in accordance with a pre-determined rule, the position of the
rows within the super frame before and after the row
permutation process is changed. If
the row permutation
process is performed by super frame units, and even though
the section having a plurality of errors occurring therein
becomes very long, and even though the number of errors
included in the RS frame, which is to be decoded, exceeds the
extent of being able to be corrected, the errors become
dispersed within the entire super frame. Thus, the decoding
ability is even more enhanced as compared to a single RS
frame.
67
CA 02888511 2015-04-20
[00240]
At this point, as an example of the present
invention, RS-encoding is applied for the error correction
encoding process, and a cyclic redundancy check (CRC)
encoding is applied for the error detection process in the
RS-CRC encoder 412. When performing the RS-encoding, parity
data that are used for the error correction are generated.
And, when performing the CRC encoding, CRC data that are used
for the error detection are generated.
The CRC data
generated by CRC encoding may be used for indicating whether
or not the mobile service data have been damaged by the
errors while being transmitted through the channel.
In the
present invention, a variety of error detection coding
methods other than the CRC encoding method may be used, or
the error correction coding method may be used to enhance the
overall error correction ability of the receiving system.
[00241]
Herein, the RS-CRC encoder 412 refers to a pre-
determined transmission parameter provided by the controller
201 so as to perform operations including RS frame
configuration, RS encoding, CRC encoding, super frame
configuration, and row permutation in super frame units.
[00242]
FIG. 23(a) and FIG. 23(b) illustrate a process of
one or two RS frame being divided into several portions,
based upon an RS frame mode value, and a process of each
portion being assigned to a corresponding region within the
respective data group. According to an embodiment of the
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CA 02888511 2015-04-20
present invention, the data assignment within the data group
is performed by the group formatter 303.
[00243]
More specifically, FIG. 23(a) shows an example of
the RS frame mode value being equal to '00'.
Herein, only
the primary encoder 410 of FIG. 22 operates, thereby forming
one RS frame for one parade. Then, the RS frame is divided
into several portions, and the data of each portion are
assigned to regions A/B/C/D within the respective data group.
FIG. 23(b) shows an example of the RS frame mode value being
equal to '01'. Herein, both the primary encoder 410 and the
secondary encoder 420 of FIG. 22 operate, thereby forming two
RS frames for one parade, i.e., one primary RS frame and one
secondary RS frame.
Then, the primary RS frame is divided
into several portions, and the secondary RS frame is divided
into several portions. At this point, the data of each
portion of the primary RS frame are assigned to regions A/B
within the respective data group. And, the data of each
portion of the secondary RS frame are assigned to regions C/D
within the respective data group.
Detailed Description of the RS Frame
[00244]
FIG. 24(a) illustrates an example of an RS frame
being generated from the RS-CRC encoder 412 according to the
present invention.
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CA 02888511 2015-04-20
[00245]
When the RS frame payload is formed, as shown in
FIG. 24(a), the RS-CRC encoder 412 performs a (Nc,Kc)-RS
encoding process on each column, so as to generate Nc-Kc(=P)
number of parity bytes.
Then, the RS-CRC encoder 412 adds
the newly generated P number of parity bytes after the very
last byte of the corresponding column, thereby creating a
column of (187+P) bytes.
Herein, as shown in FIG. 24(a), Kc
is equal to 187 (i.e., Kc=187), and Nc is equal to 187+P
(i.e., Nc=187+P).
Herein, the value of P may vary depending
upon the RS code mode. Table 6 below shows an example of an
RS code mode, as one of the RS encoding information.
Table 6
RS code Number of Parity Bytes
RS code
mode (P)
00 (211,187) 24
01 (223,187) 36
(235,187) 48
11 Reserved Reserved
[00246]
Table 6 shows an example of 2 bits being assigned
in order to indicate the RS code mode.
The RS code mode
represents the number of parity bytes corresponding to the RS
frame payload.
[00247]
For example, when the RS code mode value is equal
to '10', (235,187)-RS-encoding is performed on the RS frame
CA 02888511 2015-04-20
payload of FIG. 24(a), so as to generate 48 parity data bytes.
Thereafter, the 48 parity bytes are added after the last data
byte of the corresponding column, thereby creating a column
of 235 data bytes.
[00248]
When the RS frame mode value is equal to '00' in
Table 1 (i.e., when the RS frame mode indicates a single RS
frame), only the RS code mode of the corresponding RS frame
is indicated. However, when the RS frame mode value is equal
to '01' in Table 1 (i.e., when the RS frame mode indicates
multiple RS frames), the RS code mode corresponding to a
primary RS frame and a secondary RS frame. More specifically,
it is preferable that the RS code mode is independently
applied to the primary RS frame and the secondary RS frame.
[00249]
When such RS encoding process is performed on all N
number of columns, a size of N(row)x(187+P)(column) bytes may
be generated, as shown in FIG. 24(b).
[00250]
Each row of the RS frame payload is configured of N
bytes.
However, depending upon channel conditions between
the transmitting system and the receiving system, error may
be included in the RS frame payload.
When errors occur as
described above, CRC data (or CRC code or CRC checksum) may
be used on each row unit in order to verify whether error
exists in each row unit.
[00251]
The RS-CRC encoder 412 may perform CRC encoding on
the mobile service data being RS encoded so as to create (or
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CA 02888511 2015-04-20
generate) the CRC data. The CRC data being generated by CRC
encoding may be used to indicate whether the mobile service
data have been damaged while being transmitted through the
channel.
[00252]
The present invention may also use different error
detection encoding methods other than the CRC encoding method.
Alternatively, the present invention may use the error
correction encoding method to enhance the overall error
correction ability of the receiving system.
[00253]
FIG. 24(c) illustrates an example of using a 2-byte
(i.e., 16-bit) CRC checksum as the CRC data.
Herein, a 2-
byte CRC checksum is generated for N number of bytes of each
row, thereby adding the 2-byte CRC checksum at the end of the
N number of bytes. Thus, each row is expanded to (N+2)
number of bytes.
Equation 3 below corresponds to an
exemplary equation for generating a 2-byte CRC checksum for
each row being configured of N number of bytes.
Equation 3
g(x) = xI6 + x12 + x5 +1
[00254]
The process of adding a 2-byte checksum in each row
is only exemplary.
Therefore, the present invention is not
limited only to the example proposed in the description set
forth herein.
72
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[00255]
As described above, when the process of RS encoding
and CRC encoding are completed, the (Nx187)-byte RS frame
payload is converted into a (N+2)x(187+P)-byte RS frame.
[00256]
Based upon an error correction scenario of a RS
frame formed as described above, the data bytes within the RS
frame are transmitted through a channel in a row direction.
At this point, when a large number of errors occur during a
limited period of transmission time, errors also occur in a
row direction within the RS frame being processed with a
decoding process in the receiving system.
However, in the
perspective of RS encoding performed in a column direction,
the errors are shown as being scattered.
Therefore, error
correction may be performed more effectively. At this point,
a method of increasing the number of parity data bytes (P)
may be used in order to perform a more intense error
correction process. However, using this method may lead to a
decrease in transmission efficiency.
Therefore, a mutually
advantageous method is required.
Furthermore, when
performing the decoding process, an erasure decoding process
may be used to enhance the error correction performance.
[00257]
Additionally, the RS-CRC encoder 412 according to
the present invention also performs a row permutation (or
interleaving) process in super frame units in order to
further enhance the error correction performance when error
correction the RS frame.
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CA 02888511 2015-04-20
[00258]
FIG. 25(a) to FIG. 25(d) illustrates an example of
performing a row permutation process in super frame units
according to the present invention.
More specifically, G
number of RS frames RS-CRC-encoded is grouped to form a super
frame, as shown in FIG. 25(a). At this point, since each RS
frame is formed of (N+2)x(187+P) number of bytes, one super
frame is configured to have the size of (N+2)x(187+P)xG bytes.
[00259]
When a row permutation process permuting each row
of the super frame configured as described above is performed
based upon a pre-determined permutation rule, the positions
of the rows prior to and after being permuted (or
interleaved) within the super frame may be altered.
More
specifically, the ith row of the super frame prior to the
interleaving process, as shown in FIG. 25(b), is positioned
in the ith row of the same super frame after the row
permutation process, as shown in FIG. 25(c).
The above-
described relation between i and j can be easily understood
with reference to a permutation rule as shown in Equation 4
below.
Equation 4
j= G(mod(187 + P))+ Li /(187 + P)]
i = (187+ P)Omod 0+1_j I Gj
where 0 j (187 + P)G ¨1; or
where 0 j < (187 + P)G
74
CA 02888511 2015-04-20
[00260]
Herein, each row of the super frame is configured
of (N+2) number of data bytes even after being row-permuted
in super frame units.
[00261]
When all row permutation processes in super frame
units are completed, the super frame is once again divided
into G number of row-permuted RS frames, as shown in FIG.
25(d), and then provided to the RS frame divider 413. Herein,
the number of RS parity bytes and the number of columns
should be equally provided in each of the RS frames, which
configure a super frame. As described in the error
correction scenario of a RS frame, in case of the super frame,
a section having a large number of error occurring therein is
so long that, even when one RS frame that is to be decoded
includes an excessive number of errors (i.e., to an extent
that the errors cannot be corrected), such errors are
scattered throughout the entire super frame.
Therefore, in
comparison with a single RS frame, the decoding performance
of the super frame is more enhanced.
[00262]
The above description of the present invention
corresponds to the processes of forming (or creating) and
encoding an RS frame, when a data group is divided into
regions A/B/C/D, and when data of an RS frame are assigned to
all of regions A/B/C/D within the corresponding data group.
More specifically, the above description corresponds to an
embodiment of the present invention, wherein one RS frame is
CA 02888511 2015-04-20
transmitted using one parade.
In this embodiment, the
secondary encoder 420 does not operate (or is not active).
[00263]
Meanwhile, 2 RS frames are transmitting using one
parade, the data of the primary RS frame may be assigned to
regions A/B within the data group and be transmitted, and the
data of the secondary RS frame may be assigned to regions C/D
within the data group and be transmitted. At this point, the
primary encoder 410 receives the mobile service data that are
to be assigned to regions A/B within the data group, forms
the primary RS frame payload, and then performs RS-encoding
and CRC-encoding on the primary RS frame payload, thereby
forming the primary RS frame.
Similarly, the secondary
encoder 420 receives the mobile service data that are to be
assigned to regions C/D within the data group, forms the
secondary RS frame payload, and then performs RS-encoding and
CRC-encoding on the secondary RS frame payload thereby
forming the secondary RS frame.
More specifically, the
primary RS frame and the secondary RS frame are generated
independently.
[00264]
FIG. 26 illustrates examples of receiving the
mobile service data that are to be assigned to regions A/B
within the data group, so as to form the primary RS frame
payload, and receives the mobile service data that are to be
assigned to regions C/D within the data group, so as to form
the secondary RS frame payload, thereby performing error
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CA 02888511 2015-04-20
correction encoding and error detection encoding on each of
the first and secondary RS frame payloads.
[00265]
More specifically, FIG. 26(a) illustrates an
example of the RS-CRC encoder 412 of the primary encoder 410
receiving mobile service data of the primary ensemble that
are to be assigned to regions A/B within the corresponding
data group, so as to create an RS frame payload having the
size of N1(row)x187(column).
Then, in this example, the
primary encoder 410 performs RS-encoding on each column of
the RS frame payload created as described above, thereby
adding P1 number of parity data bytes in each column.
Finally, the primary encoder 410 performs CRC-encoding on
each row, thereby adding a 2-byte checksum in each row,
thereby forming an primary RS frame.
[00266]
FIG. 26(b) illustrates an example of the RS-CRC
encoder 422 of the secondary encoder 420 receiving mobile
service data of the secondary ensemble that are to be
assigned to regions C/D within the corresponding data group,
so as to create an RS frame payload having the size of
N2(row)x187(column). Then, in this example, the secondary
encoder 420 performs RS-encoding on each column of the RS
frame payload created as described above, thereby adding P2
number of parity data bytes in each column.
Finally, the
secondary encoder 420 performs CRC-encoding on each row,
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CA 02888511 2015-04-20
thereby adding a 2-byte checksum in each row, thereby forming
an secondary RS frame.
[00267]
At this point, each of the RS-CRC encoders 412 and
422 may refer to a pre-determined transmission parameter
provided by the controller 201, the RS-CRC encoders 412 and
422 may be informed of M/H frame information, FIC information,
RS frame information (including RS frame mode information),
RS encoding information (including RS code mode), SCCC
information (including SCCC block mode information and SCCC
outer code mode information), data group information, and
region information within a data group. The RS-CRC encoders
412 and 422 may refer to the transmission parameters for the
purpose of RS frame configuration, error correction encoding,
error detection encoding.
Furthermore, the transmission
parameters should also be transmitted to the receiving system
so that the receiving system can perform a normal decoding
process. At this point, as an example of the present
invention, the transmission parameter is transmitted through
transmission parameter channel (TPC) to a receiving system.
The TPC will be described in detail in a later.
[00268]
The data of the primary RS frame, which is encoded
by RS frame units and row-permuted by super frame units from
the RS-CRC encoder 412 of the primary encoder 410, are
outputted to the RS frame divider 413.
If the secondary
encoder 420 also operates in the embodiment of the present
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CA 02888511 2015-04-20
invention, the data of the secondary RS frame, which is
encoded by RS frame units and row-permuted by super frame
units from the RS-CRC encoder 422 of the secondary encoder
420, are outputted to the RS frame divider 423. The RS frame
divider 413 of the primary encoder 410 divides the primary RS
frame into several portions, which are then outputted to the
output multiplexer (MUX) 320. Each portion of the primary RS
frame is equivalent to a data amount that can be transmitted
by one data group.
Similarly, the RS frame divider 423 of
the secondary encoder 420 divides the secondary RS frame into
several portions, which are then outputted to the output
multiplexer (MUX) 320.
[00269]
Hereinafter, the RS frame divider 413 of the
primary RS encoder 410 will now be described in detail. Also,
in order to simplify the description of the present invention,
it is assumed that an RS frame payload having the size of
N(row)x187(column), as shown in FIG. 24(a) to FIG. 24(c),
that P number of parity data bytes are added to each column
by RS-encoding the RS frame payload, and that a 2-byte
checksum is added to each row by CRC-encoding the RS frame
payload. As a result, an RS frame having the size of (N+2)
(row) x 187+P (column) is formed. Accordingly, the RS frame
divider 413 divides (or partitions) the RS frame having the
size of (N+2) (row) x 187+P (column) into several portions,
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CA 02888511 2015-04-20
each having the size of PL (wherein PL corresponds to the
length of the RS frame portion).
[00270]
At this point, as shown in Table 2 to Table 5, the
value of PL may vary depending upon the RS frame mode, SCCC
block mode, and SCCC outer coder mode.
Also, the total
number of data bytes of the RS-encoded and CRC-encoded RS
frame is equal to or smaller than 5xNoGxPL. In this case,
the RS frame is divided (or partitioned) into OxAroG)-0
number of portions each having the size of PL and one portion
having a size equal to smaller than PL.
More specifically,
with the exception of the last portion of the RS frame, each
of the remaining portions of the RS frame has an equal size
of PL. If the size of the last portion is smaller than PL, a
stuffing byte (or dummy byte) may be inserted in order to
fill (or replace) the lacking number of data bytes, thereby
enabling the last portion of the RS frame to also be equal to
PL. Each portion of an RS frame corresponds to the amount of
data that are to be SCCC-encoded and mapped into a single
data group of a parade.
[00271]
FIG. 27(a) and FIG. 27(b) respectively illustrate
examples of adding S number of stuffing bytes, when an RS
frame having the size of (N+2)(row)x(187+P)(column) is
divided into 5xAroG number of portions, each having the size
of PL. More specifically, the RS-encoded and CRC-encoded RS
frame, shown in FIG. 27(a), is divided into several portions,
CA 02888511 2015-04-20
=
as shown in FIG. 27(b).
The number of divided portions at
the RS frame is equal to (5xAT.9() .
Particularly, the first
((5xNoG)-1) number of portions each has the size of PL, and
the last portion of the RS frame may be equal to or smaller
than PL. If the size of the last portion is smaller than PL,
a stuffing byte (or dummy byte) may be inserted in order to
fill (or replace) the lacking number of data bytes, as shown
in Equation 5 below, thereby enabling the last portion of the
RS frame to also be equal to PL.
Equation 5
S=(5xNoGxPL)-0+2)487+P))
[00272]
Herein, each portion including data having the size
of PL passes through the output multiplexer 320 of the M/H
frame encoder 301, which is then outputted to the block
processor 302.
[00273]
At this point, the mapping order of the RS frame
portions to a parade of data groups in not identical with the
group assignment order defined in Equation 1. When given the
group positions of a parade in an M/H frame, the SCCC-encoded
RS frame portions will be mapped in a time order (i.e., in a
left-to-right direction).
[00274]
For example, as shown in FIG. 11, data groups of
the 2nd parade (Parade #1) are first assigned (or allocated)
81
]
CA 02888511 2015-04-20
. .
,
to the 13th Slot (Slot #12) and then assigned to the 3rd Slot
(Slot #2). However, when the data are actually placed in the
assigned slots, the data are placed in a time sequence (or
time order, i.e., in a left-to-right direction).
More
specifically, the 1st data group of Parade #1 is placed in
Slot #2, and the 2nd data group of Parade #1 is placed in Slot
#12.
Block Processor
[00275]
Meanwhile, the block processor 302 performs an SCCC
outer encoding process on the output of the M/H frame encoder
301. More specifically, the block processor 302 receives the
data of each error correction encoded portion.
Then, the
block processor 302 encodes the data once again at a coding
rate of 1/H (wherein H is an integer equal to or greater than
2 (i.e., Lr?_2)), thereby outputting the 1/H-rate encoded data
to the group formatter 303. According to the embodiment of
the present invention, the input data are encoded either at a
coding rate of 1/2 (also referred to as "1/2-rate encoding")
or at a coding rate of 1/4 (also referred to as "1/4-rate
encoding"). The data of each portion outputted from the M/H
frame encoder 301 may include at least one of mobile service
data, RS parity data, CRC data, and stuffing data. However,
in a broader meaning, the data included in each portion may
correspond to data for mobile services. Therefore, the data
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CA 02888511 2015-04-20
included in each portion will all be considered as mobile
service data and described accordingly.
[00276]
The group formatter 303 inserts the mobile service
data SCCC-outer-encoded and outputted from the block
processor 302 in the corresponding region within the data
group, which is formed in accordance with a pre-defined rule.
Also, in association with the data deinterleaving process,
the group formatter 303 inserts various place holders (or
known data place holders) in the corresponding region within
the data group.
Thereafter, the group formatter 303
deinterleaves the data within the data group and the place
holders.
[00277]
According to the present invention, with reference
to data after being data-interleaved, as shown in FIG. 5, a
data groups is configured of 10 M/H blocks (Bl to B10) and
divided into 4 regions (A, B, C, and D).
Also, as shown in
FIG. 5, when it is assumed that the data group is divided
into a plurality of hierarchical regions, as described above,
the block processor 302 may encode the mobile service data,
which are to be inserted to each region based upon the
characteristic of each hierarchical region, at different
coding rates.
For example, the block processor 302 may
encode the mobile service data, which are to be inserted in
region A/B within the corresponding data group, at a coding
rate of 1/2.
Then, the group formatter 303 may insert the
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CA 02888511 2015-04-20
1/2-rate encoded mobile service data to region A/B.
Also,
the block processor 302 may encode the mobile service data,
which are to be inserted in region C/D within the
corresponding data group, at a coding rate of 1/4 having
higher (or stronger) error correction ability than the 1/2-
coding rate. Thereafter, the group formatter 303 may insert
the 1/2-rate encoded mobile service data to region C/D.
In
another example, the block processor 302 may encode the
mobile service data, which are to be inserted in region C/D,
at a coding rate having higher error correction ability than
the 1/4-coding rate.
Then, the group formatter 303 may
either insert the encoded mobile service data to region C/D,
as described above, or leave the data in a reserved region
for future usage.
[00278]
According to another embodiment of the present
invention, the block processor 302 may perform a 1/H-rate
encoding process in SCCC block units. Herein, the SCCC block
includes at least one M/H block.
At this point, when 1/H-
rate encoding is performed in M/H block units, the M/H blocks
(B1 to B10) and the SCCC block (SCB1 to SCB10) become
identical to one another (i.e., SCB1=B1, SCB2=B2, SCB3=B3,
SCB4=B4, SCB5=B5, SCB6=B6, SCB7=B7, SCB8=B8, SCB9=B9, and
SCB10=B10). For example, the M/H block 1 (B1) may be encoded
at the coding rate of 1/2, the M/H block 2 (B2) may be
encoded at the coding rate of 1/4, and the M/H block 3 (B3)
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CA 02888511 2015-04-20
may be encoded at the coding rate of 1/2. The coding rates
are applied respectively to the remaining M/H blocks.
[00279]
Alternatively, a plurality of M/H blocks within
regions A, B, C, and D may be grouped into one SCCC block,
thereby being encoded at a coding rate of 1/H in SCCC block
units. Accordingly, the receiving performance of region C/D
may be enhanced. For example, M/H block 1 (B1) to M/H block
(B5) may be grouped into one SCCC block and then encoded at
a coding rate of 1/2.
Thereafter, the group formatter 303
may insert the 1/2-rate encoded mobile service data to a
section starting from M/H block 1 (B1) to M/H block 5 (B5).
Furthermore, M/H block 6 (B6) to M/H block 10 (B10) may be
grouped into one SCCC block and then encoded at a coding rate
of 1/4.
Thereafter, the group formatter 303 may insert the
1/4-rate encoded mobile service data to another section
starting from M/H block 6 (B6) to M/H block 10 (B10).
In
this case, one data group may consist of two SCCC blocks.
[00280]
According to another embodiment of the present
invention, one SCCC block may be formed by grouping two M/H
blocks.
For example, M/H block 1 (B1) and M/H block 6 (B6)
may be grouped into one SCCC block (SCB1).
Similarly, M/H
block 2 (B2) and M/H block 7 (B7) may be grouped into another
SCCC block (SCB2).
Also, M/H block 3 (B3) and M/H block 8
(B8) may be grouped into another SCCC block (SCB3). And, M/H
block 4 (B4) and M/H block 9 (B9) may be grouped into another
CA 02888511 2015-04-20
SCCC block (SCB4).
Furthermore, M/H block 5 (B5) and M/H
block 10 (B10) may be grouped into another SCCC block (SCB5).
In the above-described example, the data group may consist of
M/H blocks and 5 SCCC blocks. Accordingly, in a data (or
signal) receiving environment undergoing frequent and severe
channel changes, the receiving performance of regions C and D,
which is relatively more deteriorated than the receiving
performance of region A, may be reinforced.
Furthermore,
since the number of mobile service data symbols increases
more and more from region A to region D, the error correction
encoding performance becomes more and more deteriorated.
Therefore, when grouping a plurality of M/H block to form one
SCCC block, such deterioration in the error correction
encoding performance may be reduced.
[00281]
As described-above, when the block processor 302
performs encoding at a 1/H-coding rate, information
associated with SCCC should be transmitted to the receiving
system in order to accurately recover the mobile service data.
Table 7 below shows an example of a SCCC block mode, which
indicating the relation between an M/H block and an SCCC
block, among diverse SCCC block information.
Table 7
SCCC
Block 00 01 10 11
Mode
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CA 02888511 2015-04-20
One M/H Two M/H
Re
Descrip Block Blocks Re
tion per SCCC per SCCC served serve
Block Block
SCB SCB input, SCB input,
M/H Block M/H Blocks
SCB1 Dl Bl + B6
SCB2 B2 B2 + B7
SCB3 B3 B3 + B8
SCB4 B4 B4 + B9
SCB5 B5 B5 + B10
SCB6 56
SCB7 B7
SCB8 58
SCB9 B9
SCB10 B10
[00282]
More specifically, Table 4 shows an example of 2
bits being allocated in order to indicate the SCCC block mode.
For example, when the SCCC block mode value is equal to '00',
this indicates that the SCCC block and the M/H block are
identical to one another.
Also, when the SCCC block mode
value is equal to '01', this indicates that each SCCC block
is configured of 2 M/H blocks.
[00283]
As described above, if one data group is configured
of 2 SCCC blocks, although it is not indicated in Table 7,
this information may also be indicated as the SCCC block mode.
For example, when the SCCC block mode value is equal to '10',
this indicates that each SCCC block is configured of 5 M/H
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CA 02888511 2015-04-20
. .
blocks and that one data group is configured of 2 SCCC blocks.
Herein, the number of M/H blocks included in an SCCC block
and the position of each M/H block may vary depending upon
the settings made by the system designer.
Therefore, the
present invention will not be limited to the examples given
herein.
Accordingly, the SCCC mode information may also be
expanded.
[00284]
An example of a coding rate information of the SCCC
block, i.e., SCCC outer code mode, is shown in Table 8 below.
Table 8
SCCC outer
Description
code mode (2 bits)
00 Outer code rate of SCCC block
is 1/2 rate
01 Outer code rate of SCCC block
is 1/4 rate
Reserved
11 Reserved
[00285]
More specifically, Table 8 shows an example of 2
bits being allocated in order to indicate the coding rate
information of the SCCC block.
For example, when the SCCC
outer code mode value is equal to '00', this indicates that
the coding rate of the corresponding SCCC block is 1/2. And,
when the SCCC outer code mode value is equal to '01', this
indicates that the coding rate of the corresponding SCCC
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= =
block is 1/4.
[00286]
If the SCCC block mode value of Table 7 indicates
'00', the SCCC outer code mode may indicate the coding rate
of each M/H block with respect to each M/H block.
In this
case, since it is assumed that one data group includes 10 M/H
blocks and that 2 bits are allocated for each SCCC block mode,
a total of 20 bits are required for indicating the SCCC block
modes of the 10 M/H modes. In another example, when the SCCC
block mode value of Table 7 indicates '00', the SCCC outer
code mode may indicate the coding rate of each region with
respect to each region within the data group. In this case,
since it is assumed that one data group includes 4 regions
(i.e., regions A, B, C, and D) and that 2 bits are allocated
for each SCCC block mode, a total of 8 bits are required for
indicating the SCCC block modes of the 4 regions. In another
example, when the SCCC block mode value of Table 7 is equal
to '01', each of the regions A, B, C, and D within the data
group has the same SCCC outer code mode.
[00287]
Meanwhile, an example of an SCCC output block
length (SOBL) for each SCCC block, when the SCCC block mode
value is equal to '00', is shown in Table 9 below.
Table 9
SIBL
SCCC Block SOBL 1/2 1/4
rate rate
89
CA 02888511 2015-04-20
SCB1 (B1) 528 264 132
SCB2 (B2) 1536 768 384
SCB3 (B3) 2376 1188 594
SCB4 (B4) 2388 1194 597
SCB5 (B5) 2772 1386 693
SCB6 (B6) 2472 1236 618
SCB7 (B7) 2772 1386 693
SCB8 (B8) 2508 1254 627
SCB9 (B9) 1416 708 354
SCB10 (B10) 480 240 120
[00288]
More specifically, when given the SCCC output block
length (SOBL) for each SCCC block, an SCCC input block length
(SIBL) for each corresponding SCCC block may be decided based
upon the outer coding rate of each SCCC block. The SOBL is
equivalent to the number of SCCC output (or outer-encoded)
bytes for each SCCC block.
And, the SIBL is equivalent to
the number of SCCC input (or payload) bytes for each SCCC
block. Table 10 below shows an example of the SOBL and SIBL
for each SCCC block, when the SCCC block Mode value is equal
to '01'.
Table 10
SIBL
SCCC Block SOBL 1/2 1/4
rate rate
SCB1 (B1+B6) 528 264 132
SCB2 (B2+B7) 1536 768 384
CA 02888511 2015-04-20
SCB3 (B3+B8) 2376 1188 594
SCB4 (B4+B9) 2388 1194 597
SCB5 (B5+B10) 2772 1386 693
[00289]
In order to do so, as shown in FIG. 28, the block
processor 302 includes a RS frame portion-SCCC block
converter 511, a byte-bit converter 512, a convolution
encoder 513, a symbol interleaver 514, a symbol-byte
converter 515, and an SCCC block-M/H block converter 516.
The convolutional encoder 513 and the symbol interleaver 514
are virtually concatenated with the trellis encoding module
in the post-processor in order to configure an SCCC block.
More specifically, the RS frame portion-SCCC block converter
511 divides the RS frame portions, which are being inputted,
into multiple SCCC blocks using the SIBL of Table 9 and Table
based upon the RS code mode, SCCC block mode, and SCCC
outer code mode.
Herein, the M/H frame encoder 301 may
output only primary RS frame portions or both primary RS
frame portions and secondary RS frame portions in accordance
with the RS frame mode.
[00290]
When the RS Frame mode is set to '00', a portion of
the primary RS Frame equal to the amount of data, which are
to be SCCC outer encoded and mapped to 10 M/H blocks (Bl to
B10) of a data group, will be provided to the block processor
302. When the SCCC block mode value is equal to '00', then
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the primary RS frame portion will he split into 10 SCCC
Blocks according to Table 9. Alternatively, when the SCCC
block mode value is equal to '01', then the primary RS frame
will be split into 5 SCCC blocks according to Table 10.
[00291]
When the RS frame mode value is equal to '01',
then the block processor 302 may receive two RS frame
portions. The RS frame mode value of '01' will not be used
with the SCCC block mode value of '01'.
The first portion
from the primary RS frame will be SCCC-outer-encoded as SCCC
Blocks SCB3, SCB4, SCB5, SCB6, SCB7, and SCB8 by the block
processor 302. The SCCC Blocks SCB3 and SCB8 will be mapped
to region B and the SCCC blocks SCB4, SCB5, SCB6, and SCB7
shall be mapped to region A by the group formatter 303. The
second portion from the secondary RS frame will also be SCCC-
outer-encoded, as SCB1, SCB2, SCB9, and SCB10, by the block
processor 302.
The group formatter 303 will map the SCCC
blocks SCB1 and SCB10 to region D as the M/H blocks Bl and
B10, respectively. Similarly, the SCCC blocks SCB2 and SCB9
will be mapped to region C as the M/H blocks B2 and B9.
[00292]
The byte-bit converter 512 identifies the mobile
service data bytes of each SCCC block outputted from the RS
frame portion-SCCC block converter 511 as data bits, which
are then outputted to the convolution encoder 513.
The
convolution encoder 513 performs one of 1/2-rate encoding and
1/4-rate encoding on the inputted mobile service data bits.
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[00293]
FIG. 29 illustrates a detailed block diagram of the
convolution encoder 513.
The convolution encoder 513
includes two delay units 521 and 523 and three adders 522,
524, and 525. Herein, the convolution encoder 513 encodes an
input data bit U and outputs the coded bit U to 5 bits (u0 to
u4).
At this point, the input data bit U is directly
outputted as uppermost bit u0 and simultaneously encoded as
lower bit ulu2u3u4 and then outputted.
More specifically,
the input data bit U is directly outputted as the uppermost
bit u0 and simultaneously outputted to the first and third
adders 522 and 525.
[00294]
The first adder 522 adds the input data bit U and
the output bit of the first delay unit 521 and, then, outputs
the added bit to the second delay unit 523. Then, the data
bit delayed by a pre-determined time (e.g., by 1 clock) in
the second delay unit 523 is outputted as a lower bit ul and
simultaneously fed-back to the first delay unit 521.
The
first delay unit 521 delays the data bit fed-back from the
second delay unit 523 by a pre-determined time (e.g., by 1
clock).
Then, the first delay unit 521 outputs the delayed
data bit as a lower bit u2 and, at the same time, outputs the
fed-back data to the first adder 522 and the second adder 524.
The second adder 524 adds the data bits outputted from the
first and second delay units 521 and 523 and outputs the
added data bits as a lower bit u3. The third adder 525 adds
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CA 02888511 2015-04-20
the input data bit U and the output of the second delay unit
523 and outputs the added data bit as a lower bit u4.
[00295]
At this point, the first and second delay units 521
and 523 are reset to '0', at the starting point of each SCCC
block. The convolution encoder 513 of FIG. 29 may be used as
a 1/2-rate encoder or a 1/4-rate encoder. More specifically,
when a portion of the output bit of the convolution encoder
513, shown in FIG. 29, is selected and outputted, the
convolution encoder 513 may be used as one of a 1/2-rate
encoder and a 1/4-rate encoder.
Table 11 below shown an
example of output symbols of the convolution encoder 513.
Table 11
Reg 1/2 1/4 rate
ion rate
SCCC block mode SCCC
block
= '00' mode
= '01'
A, (u0, (u0, u2), (ul, (u0, u2),
ul) u3) (ul, u4)
C, (u0, ul), (u3,
ID u4)
[00296]
For example, at the 1/2-coding rate, 1 output
symbol (i.e., u0 and ul bits) may be selected and outputted.
And, at the 1/4-coding rate, depending upon the SCCC block
mode, 2 output symbols (i.e., 4 bits) may be selected and
outputted.
For example, when the SCCC block mode value is
equal to '01', and when an output symbol configured of u0 and
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CA 02888511 2015-04-20
u2 and another output symbol configured of ul and u4 are
selected and outputted, a 1/4-rate coding result may be
obtained.
[00297]
The mobile service data encoded at the coding rate
of 1/2 or 1/4 by the convolution encoder 513 are outputted to
the symbol interleaver 514. The symbol interleaver 514
performs block interleaving, in symbol units, on the output
data symbol of the convolution encoder 513.
More
specifically, the symbol interleaver 514 is a type of block
interleaver.
Any interleaver performing structural
rearrangement (or realignment) may be applied as the symbol
interleaver 514 of the block processor.
However, in the
present invention, a variable length symbol interleaver that
can be applied even when a plurality of lengths is provided
for the symbol, so that its order may be rearranged, may also
be used.
[00298]
FIG. 30 illustrates a symbol interleaver according
to an embodiment of the present invention. Particularly, FIG.
30 illustrates an example of the symbol interleaver when
B=2112 and L=4096.
Herein, B indicates a block length in
symbols that are outputted for symbol interleaving from the
convolution encoder 513. And, L represents a block length in
symbols that are actually interleaved by the symbol
interleaver 514. At this point, the block length in symbols
B inputted to the symbol interleaver 514 is equivalent to
CA 02888511 2015-04-20
=
4xSOBL .
More specifically, since one symbol is configured
of 2 bits, the value of B may be set to be equal to 4xSOBL.
[00299]
In the present invention, when performing the
symbol-intereleaving process, the conditions of L=2'
(wherein m is an integer) and of
should be satisfied.
If there is a difference in value between B and L, (L-B)
number of null (or dummy) symbols is added, thereby creating
an interleaving pattern, as shown in P'(i) of FIG. 30.
Therefore, B becomes a block size of the actual symbols that
are inputted to the symbol interleaver 514 in order to be
interleaved. L
becomes an interleaving unit when the
interleaving process is performed by an interleaving pattern
created from the symbol interleaver 514.
[00300]
Equation 6 shown below describes the process of
sequentially receiving B number of symbols, the order of
which is to be rearranged, and obtaining an L value
satisfying the conditions of L=2' (wherein m is an integer)
and of ,
thereby creating the interleaving so as to
realign (or rearrange) the symbol order.
Equation 6
In relation to all places, wherein OB-1,
MO= {89x1x(i+1)/2}modL
Herein, L?_B, L=2", wherein m is an integer.
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CA 02888511 2015-04-20
=
[00301]
As shown in P'(i) of FIG. 30, the order of B number
of input symbols and (L-B) number of null symbols is
rearranged by using the above-mentioned Equation 6. Then, as
shown in P(i) of FIG. 30, the null byte places are removed,
so as to rearrange the order. Starting with the lowest value
of i, the P(i) are shifted to the left in order to fill the
empty entry locations.
Thereafter, the symbols of the
aligned interleaving pattern P(i) are outputted to the
symbol-byte converter 515 in order. Herein, the symbol-byte
converter 515 converts to bytes the mobile service data
symbols, having the rearranging of the symbol order completed
and then outputted in accordance with the rearranged order,
and thereafter outputs the converted bytes to the SCCC block-
M/H block converter 516. The SCCC block-M/H block converter
516 converts the symbol-interleaved SCCC blocks to M/H blocks,
which are then outputted to the group formatter 303.
[00302]
If the SCCC block mode value is equal to '00', the
SCCC block is mapped at a one-to-one (1:1) correspondence
with each M/H block within the data group.
In another
example, if the SCCC block mode value is equal to '01', each
SCCC block is mapped with two M/H blocks within the data
group. For example, the SCCC block SCB1 is mapped with (B1,
B6), the SCCC block SCB2 is mapped with (B2, B7), the SCCC
block SCB3 is mapped with (B3, B8), the SCCC block SCB4 is
mapped with (B4, B9), and the SCCC block SCB5 is mapped with
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CA 02888511 2015-04-20
(B5, B10).
The M/H block that is outputted from the SCCC
block-M/H block converter 516 is configured of mobile service
data and FEC redundancy.
In the present invention, the
mobile service data as well as the FEC redundancy of the M/H
block will be collectively considered as mobile service data.
Group Formatter
[00303]
The group formatter 303 inserts data of M/H blocks
outputted from the block processor 302 to the corresponding
M/H blocks within the data group, which is formed in
accordance with a pre-defined rule.
Also, in association
with the data-deinterleaving process, the group formatter 303
inserts various place holders (or known data place holders)
in the corresponding region within the data group.
More
specifically, apart from the encoded mobile service data
outputted from the block processor 302, the group formatter
303 also inserts MPEG header place holders, non-systematic RS
parity place holders, main service data place holders, which
are associated with the data deinterleaving in a later
process, as shown in FIG. 5.
[00304]
Herein, the main service data place holders are
inserted because the mobile service data bytes and the main
service data bytes are alternately mixed with one another in
regions B to D based upon the input of the data deinterleaver,
as shown in FIG. 5.
For example, based upon the data
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CA 02888511 2015-04-20
outputted after data deinterleaving, the place holder for the
MPEG header may be allocated at the very beginning of each
packet. Also, in order to configure an intended group format,
dummy bytes may also be inserted.
Furthermore, the group
formatter 303 inserts initialization data (i.e., trellis
initialization byte) of the trellis encoding module 256 in
the corresponding regions.
For example, the initialization
data may be inserted in the beginning of the known data
sequence.
The initialization data is used for initializing
memories within the trellis encoding module 256, and is not
transmitted to the receiving system.
[00305]
Additionally, the group formatter 303 may also
insert signaling information, which are encoded and outputted
from the signaling encoder 304, in corresponding regions
within the data group. At this point, reference may be made
to the signaling information when the group formatter 303
inserts each data type and respective place holders in the
data group.
The process of encoding the signaling
information and inserting the encoded signaling information
to the data group will be described in detail in a later
process.
[00306]
After inserting each data type and respective place
holders in the data group, the group formatter 303 may
deinterleave the data and respective place holders, which
have been inserted in the data group, as an inverse process
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CA 02888511 2015-04-20
of the data interleaver, thereby outputting the deinterleaved
data and respective place holders to the packet formatter 305.
The group formatter 303 may include a group format organizer
527, and a data deinterleaver 529, as shown in FIG. 31. The
group format organizer 527 inserts data and respective place
holders in the corresponding regions within the data group,
as described above.
And, the data deinterleaver 529
deinterleaves the inserted data and respective place holders
as an inverse process of the data interleaver.
[00307]
The packet formatter 305 removes the main service
data place holders and the RS parity place holders that were
allocated for the deinterleaving process from the
deinterleaved data being inputted.
Then, the packet
formatter 305 groups the remaining portion and inserts the 3-
byte MPEG header place holder in an MPEG header having a null
packet PID (or an unused PID from the main service data
packet).
Furthermore, the packet formatter 305 adds a
synchronization data byte at the beginning of each 187-byte
data packet.
Also, when the group formatter 303 inserts
known data place holders, the packet formatter 303 may insert
actual known data in the known data place holders, or may
directly output the known data place holders without any
modification in order to make replacement insertion in a
later process.
Thereafter, the packet formatter 305
identifies the data within the packet-formatted data group,
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CA 02888511 2015-04-20
as described above, as a 188-byte unit mobile service data
packet (i.e., MPEG TS packet), which is then provided to the
packet multiplexer 240.
[00308]
Based upon the control of the controller 201, the
packet multiplexer 240 multiplexes the data group packet-
formatted and outputted from the packet formatter 306 and the
main service data packet outputted from the packet jitter
mitigator 220. Then, the packet multiplexer 240 outputs the
multiplexed data packets to the data randomizer 251 of the
post-processor 250. More specifically, the controller 201
controls the time-multiplexing of the packet multiplexer 240.
If the packet multiplexer 240 receives 118 mobile service
data packets from the packet formatter 305, 37 mobile service
data packets are placed before a place for inserting VSB
field synchronization. Then, the remaining 81 mobile service
data packets are placed after the place for inserting VSB
field synchronization.
The multiplexing method may be
adjusted by diverse variables of the system design.
The
multiplexing method and multiplexing rule of the packet
multiplexer 240 will be described in more detail in a later
process.
[00309]
Also, since a data group including mobile service
data in-between the data bytes of the main service data is
multiplexed (or allocated) during the packet multiplexing
process, the shifting of the chronological position (or
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CA 02888511 2015-04-20
place) of the main service data packet becomes relative.
Also, a system object decoder (i.e., MPEG decoder) for
processing the main service data of the receiving system,
receives and decodes only the main service data and
recognizes the mobile service data packet as a null data
packet.
[00310]
Therefore, when the system object decoder of the
receiving system receives a main service data packet that is
multiplexed with the data group, a packet jitter occurs.
[00311]
At this point, since a multiple-level buffer for
the video data exists in the system object decoder and the
size of the buffer is relatively large, the packet jitter
generated from the packet multiplexer 240 does not cause any
serious problem in case of the video data.
However, since
the size of the buffer for the audio data in the object
decoder is relatively small, the packet jitter may cause
considerable problem.
More specifically, due to the packet
jitter, an overflow or underflow may occur in the buffer for
the main service data of the receiving system (e.g., the
buffer for the audio data).
Therefore, the packet jitter
mitigator 220 re-adjusts the relative position of the main
service data packet so that the overflow or underflow does
not occur in the system object decoder.
[00312]
In the present invention, examples of repositioning
places for the audio data packets wLthin the main service
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CA 02888511 2015-04-20
data in order to minimize the influence on the operations of
the audio buffer will be described in detail.
The packet
jitter mitigator 220 repositions the audio data packets in
the main service data section so that the audio data packets
of the main service data can be as equally and uniformly
aligned and positioned as possible.
Additionally, when the
positions of the main service data packets are relatively re-
adjusted, associated program clock reference (PCR) values may
also be modified accordingly. The PCR value corresponds to a
time reference value for synchronizing the time of the MPEG
decoder.
Herein, the PCR value is inserted in a specific
region of a TS packet and then transmitted.
[00313]
In the example of the present invention, the packet
jitter mitigator 220 also performs the operation of modifying
the PCR value. The output of the padket jitter mitigator 220
is inputted to the packet multiplexer 240.
As described
above, the packet multiplexer 240 multiplexes the main
service data packet outputted from the packet jitter
mitigator 220 with the mobile service data packet outputted
from the pre-processor 230 into a burst structure in
accordance with a pre-determined multiplexing rule.
Then,
the packet multiplexer 240 outputs the multiplexed data
packets to the data randomizer 251 of the post-processor 250.
[00314]
If the inputted data correspond to the main service
data packet, the data randomizer 251 performs the same
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CA 02888511 2015-04-20
randomizing process as that of the conventional randomizer.
More specifically, the synchronization byte within the main
service data packet is deleted. Then, the remaining 187 data
bytes are randomized by using a pseudo random byte generated
from the data randomizer 251.
Thereafter, the randomized
data are outputted to the RS encoder/non-systematic RS
encoder 252.
On the other hand, if the inputted data
correspond to the mobile service data packet, the data
randomizer 251 may not perform a randomizing process on the
mobile service data packet.
[00315]
The RS encoder/non-systematic RS encoder 252
performs an RS encoding process on the data being randomized
by the data randomizer 251 or on the data bypassing the data
randomizer 251, so as to add 20 bytes of RS parity data.
Thereafter, the processed data are outputted to the data
interleaver 253. Herein, if the inputted data correspond to
the main service data packet, the RS encoder/non-systematic
RS encoder 252 performs the same systematic RS encoding
process as that of the conventional broadcasting system,
thereby adding the 20-byte RS parity data at the end of the
187-byte data.
Alternatively, if the inputted data
correspond to the mobile service data packet, the RS
encoder/non-systematic RS encoder 252 performs a non-
systematic RS encoding process.
At this point, the 20-byte
RS parity data obtained from the non-systematic RS encoding
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CA 02888511 2015-04-20
=
process are inserted in a pre-decided parity byte place
within the mobile service data packet.
[00316]
The data interleaver 253 corresponds to a byte unit
convolutional interleaver.
The output of the data
interleaver 253 is inputted to the parity replacer 254 and to
the non-systematic RS encoder 255.
[00317]
Meanwhile, a process of initializing a memory
within the trellis encoding module 256 is primarily required
in order to decide the output data of the trellis encoding
module 256, which is located after the parity replacer 254,
as the known data pre-defined according to an agreement
between the receiving system and the transmitting system.
More specifically, the memory of the trellis encoding module
256 should first be initialized before the received known
data sequence is trellis-encoded.
[00318]
At this point, the beginning portion of the known
data sequence that is received corresponds to the
initialization data and not to the actual known data. Herein,
the initialization data has been included in the data by the
group formatter within the pre-processor 230 in an earlier
process.
Therefore, the process of replacing the
initialization data with memory values within the trellis
encoding module 256 are required to be performed immediately
before the inputted known data sequence is trellis-encoded.
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CA 02888511 2015-04-20
[00319]
More specifically, the initialization data are
replaced with the memory value within the trellis encoding
module 256, thereby being inputted to the trellis encoding
module 256.
At this point, the memory value replacing the
initialization data are process with (or calculated by) an
exclusive OR (XOR) operation with the respective memory value
within the trellis encoding module 256, so as to be inputted
to the corresponding memory.
Therefore, the corresponding
memory is initialized to '0'.
Additionally, a process of
using the memory value replacing the initialization data to
re-calculate the RS parity, so that the re-calculated RS
parity value can replace the RS parity being outputted from
the data interleaver 253, is also required.
[00320]
Therefore, the non-systematic RS encoder 255
receives the mobile service data packet including the
initialization data from the data interleaver 253 and also
receives the memory value from the trellis encoding module
256.
[00321]
Among the inputted mobile service data packet, the
initialization data are replaced with the memory value, and
the RS parity data that are added to the mobile service data
packet are removed and processed with non-systematic RS
encoding.
Thereafter, the new RS parity obtained by
performing the non-systematic RS encoding process is
outputted to the parity replacer 255.
Accordingly, the
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CA 02888511 2015-04-20
parity replacer 255 selects the output of the data
interleaver 253 as the data within the mobile service data
packet, and the parity replacer 255 selects the output of the
non-systematic RS encoder 255 as the RS parity. The selected
data are then outputted to the trellis encoding module 256.
[00322]
Meanwhile, if the main service data packet is
inputted or if the mobile service data packet, which does not
include any initialization data that are to be replaced, is
inputted, the parity replacer 254 selects the data and RS
parity that are outputted from the data interleaver 253.
Then, the parity replacer 254 directly outputs the selected
data to the trellis encoding module 256 without any
modification.
The trellis encoding module 256 converts the
byte-unit data to symbol units and performs a 12-way
interleaving process so as to trellis-encode the received
data.
Thereafter, the processed data are outputted to the
synchronization multiplexer 260.
[00323]
FIG. 32 illustrates a detailed diagram of one of 12
trellis encoders included in the trellis encoding module 256.
Herein, the trellis encoder includes first and second
multiplexers 531 and 541, first and second exclusive OR (XOR)
gates 532 and 542, and first to third memories 533, 542, and
544.
[00324]
More specifically, the first to third memories 533,
542, and 544 are initialized by the memory value instead of
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CA 02888511 2015-04-20
=
the initialization data from the parity replacer 254.
More
specifically, when the first symbol (i.e., two bits), which
are converted from initialization data (i.e., each trellis
initialization data byte), are inputted, the input bits of
the trellis encoder will be replaced by the memory values of
the trellis encoder, as shown in FIG. 32.
[00325]
Since 2 symbols (i.e., 4 bits) are required for
trellis initialization, the last 2 symbols (i.e., 4 bits)
from the trellis initialization bytes are not used for
trellis initialization and are considered as a symbol from a
known data byte and processed accordingly.
[00326]
When the trellis encoder is in the initialization
mode, the input comes from an internal trellis status (or
state) and not from the parity replacer 254.
When the
trellis encoder is in the normal mode, the input symbol
(X2X1) provided from the parity replacer 254 will be
processed.
The trellis encoder provides the converted (or
modified) input data for trellis initialization to the non-
systematic RS encoder 255.
[00327]
More specifically, when a selection signal
designates a normal mode, the first multiplexer 531 selects
an upper bit X2 of the input symbol. And, when a selection
signal designates an initialization mode, the first
multiplexer 531 selects the output of the first memory 533
and outputs the selected output data to the first XOR gate
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532.
The first XOR gate 532 performs XOR operation on the
output of the first multiplexer 531 and the output of the
first memory 533, thereby outputting the added result to the
first memory 533 and, at the same time, as a most significant
(or uppermost) bit Z2.
The first memory 533 delays the
output data of the first XOR gate 532 by 1 clock, thereby
outputting the delayed data to the first multiplexer 531 and
the first XOR gate 532.
[00328]
Meanwhile, when a selection signal designates a
normal mode, the second multiplexer 541 selects a lower bit
X1 of the input symbol. And, when a selection signal
designates an initialization mode, the second multiplexer 541
selects the output of the second memory 542, thereby
outputting the selected result to the second XOR gate 543 and,
at the same time, as a lower bit Zl. The second XOR gate 543
performs XOR operation on the output of the second
multiplexer 541 and the output of the second memory 542,
thereby outputting the added result to the third memory 544.
The third memory 544 delays the output data of the second XOR
gate 543 by 1 clock, thereby outputting the delayed data to
the second memory 542 and, at the same time, as a least
significant (or lowermost) bit ZO.
The second memory 542
delays the output data of the third memory 544 by 1 clock,
thereby outputting the delayed data to the second XOR gate
543 and the second multiplexer 541.
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[00329]
The select signal designates an initialization mode
during the first two symbols that are converted from the
initialization data.
[00330]
For example, when the select signal designates an
initialization mode, the first XOR gate 532 performs an XOR
operation on the value of the first memory 533, which is
provided through the first multiplexer 531, and on a memory
value that is directly provided from the first memory 533.
That is, the first XOR gate 532 performs an XOR operation on
2 bits having the same value. Generally, when only one of the
two bits belonging to the operand is '1', the result of the
XOR gate is equal to '1'.
Otherwise, the result of the XOR
gate becomes equal to '0'. Therefore, when the value of the
first memory 533 is processed with an XOR operation, the
result is always equal to '0'. Furthermore, since the output
of the first XOR gate 532, i.e., '0', is inputted to the
first memory 533, the first memory 533 is initialized to '0'.
[00331]
Similarly, when the select signal designates an
initialization mode, the second XOR gate 543 performs an XOR
operation on the value of the second memory 542, which is
provided through the second multiplexer 541, and on a memory
value that is directly provided from the second memory 542.
Therefore, the output of the second XOR gate 543 is also
always equal to '0'. Since the output of the second XOR gate
543, i.e., '0', is inputted to the third memory 544, the
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. .
third memory 544 is also initialized to '0'.
The output of
the third memory 544 is inputted to the second memory 542 in
the next clock, thereby initializing the second memory 542 to
'0'.
In this case also, the select signal designates the
initialization mode.
[00332]
More specifically, when the first symbol being
converted from the initialization data byte replaces the
values of the first memory 533 and the second memory 542,
thereby being inputted to the trellis encoder, each of the
first and third memories 533 and 544 within the trellis
encoder is initialized to '00'. Following the process, when
the second symbol being converted from the initialization
data byte replaces the values of the first memory 533 and the
second memory 542, thereby being inputted to the trellis
encoder, each of the first, second, and third memories 533,
542, and 544 within the trellis encoder is initialized to
'000'.
[00333]
As described above, 2 symbols are required to
initialize the memory of the trellis encoder. At this point,
while the select signal designates an initialization mode,
the output bits (X2'X1') of the first and second memories 533
and 542 are inputted to the non-systematic RS encoder 255, so
as to perform a new RS parity calculation process.
[00334]
The synchronization multiplexer 260 inserts a field
synchronization signal and a segment synchronization signal
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, .
to the data outputted from the trellis encoding module 256
and, then, outputs the processed data to the pilot inserter
271 of the transmission unit 270. Herein, the data having a
pilot inserted therein by the pilot inserter 271 are
modulated by the modulator 272 in accordance with a pre-
determined modulating method (e.g., a VSB method).
Thereafter, the modulated data are transmitted to each
receiving system though the radio frequency (RF) up-converter
273.
Multiplexing Method of Packet Multiplexer
[00335]
Data of the error correction encoded and 1/H-rate
encoded primary RS frame (i.e., when the RS frame mode value
is equal to '00') or primary/secondary RS frame (i.e., when
the RS frame mode value is equal to '01'), are divided into a
plurality of data groups by the group formatter 303.
Then,
the divided data portions are assigned to at least one of
regions A to D of each data group or to an M/H block among
the M/H blocks B1 to B10, thereby being deinterleaved. Then,
the deinterleaved data group passes through the packet
formatter 305, thereby being multiplexed with the main
service data by the packet multiplexer 240 based upon a de-
decided multiplexing rule.
The packet multiplexer 240
multiplexes a plurality of consecutive data groups, so that
the data groups are assigned to be spaced as far apart from
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one another as possible within the sub-frame.
For example,
when it is assumed that 3 data groups are assigned to a sub-
frame, the data groups are assigned to a 1st slot (Slot #0), a
5th slot (Slot #4), and a 9th slot (Slot #8) in the sub-frame,
respectively.
[00336]
As described-above, in the assignment of the
plurality of consecutive data groups, a plurality of parades
are multiplexed and outputted so as to be spaced as far apart
from one another as possible within a sub-frame. For example,
the method of assigning data groups and the method of
assigning parades may be identically applied to all sub-
frames for each M/H frame or differently applied to each M/H
frame.
[00337]
FIG. 10 illustrates an example of a plurality of
data groups included in a single parade, wherein the number
of data groups included in a sub-frame is equal to '3', and
wherein the data groups are assigned to an M/H frame by the
packet multiplexer 240. Referring to FIG. 10, 3 data groups
are sequentially assigned to a sub-frame at a cycle period of
4 slots. Accordingly, when this process is equally performed
in the 5 sub-frames included in the corresponding M/H frame,
15 data groups are assigned to a single M/H frame.
Herein,
the 15 data groups correspond to data groups included in a
parade.
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[00338]
When data groups of a parade are assigned as shown
in FIG. 10, the packet multiplexer 240 may either assign main
service data to each data group, or assign data groups
corresponding to different parades between each data group.
More specifically, the packet multiplexer 240 may assign data
groups corresponding to multiple parades to one M/H frame.
Basically, the method of assigning data groups corresponding
to multiple parades is very similar to the method of
assigning data groups corresponding to a single parade.
In
other words, the packet multiplexer 240 may assign data
groups included in other parades to an M/H frame according to
a cycle period of 4 slots. At this point, data groups of a
different parade may be sequentially assigned to the
respective slots in a circular method.
Herein, the data
groups are assigned to slots starting from the ones to which
data groups of the previous parade have not yet been assigned.
For example, when it is assumed that data groups
corresponding to a parade are assigned as shown in FIG. 10,
data groups corresponding to the next parade may be assigned
to a sub-frame starting either from the 12th slot of a sub-
frame.
[00339]
FIG. 11 illustrates an example of assigning and
transmitting 3 parades (Parade #0, Parade #1, and Parade #2)
to an M/H frame. For example, when the 1st parade (Parade #0)
includes 3 data groups for each sub-frame, the packet
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multiplexer 240 may obtain the positions of each data groups
within the sub-frames by substituting values '0' to '2' for i
in Equation 1. More specifically, the data groups of the 1st
parade (Parade #0) are sequentially assigned to the 1st, 5th,
and 9th slots (Slot #0, Slot #4, and Slot #8) within the sub-
frame. Also, when the 2nd parade includes 2 data groups for
each sub-frame, the packet multiplexer 240 may obtain the
positions of each data groups within the sub-frames by
substituting values '3' and '4' for i in Equation 1.
More
specifically, the data groups of the 2nd parade (Parade #1)
are sequentially assigned to the 2nd and 12th slots (Slot #3
and Slot #11) within the sub-frame.
Finally, when the 3th
parade includes 2 data groups for each sub-frame, the packet
multiplexer 240 may obtain the positions of each data groups
within the sub-frames by substituting values '5' and '6' for
I in Equation 1. More specifically, the data groups of the
3rd parade (Parade #2) are sequentially assigned and outputted
to the 7th and 11th slots (Slot #6 and Slot #10) within the
sub-frame.
[00340]
As described above, the packet multiplexer 240 may
multiplex and output data groups of multiple parades to a
single M/H frame, and, in each sub-frame, the multiplexing
process of the data groups may be performed serially with a
group space of 4 slots from left to right.
Therefore, a
number of groups of one parade per sub-frame (NOG) may
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=
correspond to any one integer from '1' to '8'. Herein, since
one M/H frame includes 5 sub-frames, the total number of data
groups within a parade that can be allocated to an M/H frame
may correspond to any one multiple of '5' ranging from '5' to
'40'.
Processing Signaling Information
[00341]
The present invention assigns signaling information
areas for inserting signaling information to some areas
within each data group.
[00342]
FIG. 33 illustrates an example of assigning
signaling information areas for inserting signaling
information starting from the 1st segment of the 4th M/H block
(B4) to a portion of the 2nd segment.
More specifically,
276(=207+69) bytes of the 4th M/H block (B4) in each data
group are assigned as the signaling information area.
In
other words, the signaling information area consists of 207
bytes of the 1st segment and the first 69 bytes of the 2nd
segment of the 4th M/H block (B4).
For example, the 1st
segment of the 4th M/H block (B4) corresponds to the 17th or
173rd segment of a VSB field.
[00343]
For example, when the data group includes 6 known
data sequences, as shown in FIG. 38 and FIG. 39, the
signaling information area is located between the first known
data sequence and the second known data sequence.
More
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specifically, the first known data sequence is inserted in
the last 2 segments of the 3rd M/H block (B3), and the second
known data sequence in inserted in the 2nd and 3rd segments of
the 4th M/H block (B4). Furthermore, the 3rd to 6th known data
sequences are respectively inserted in the last 2 segments of
each of the 4th, 5th, 6th, and 7th M/H blocks (B4, B5, B6, and
B7).
The 1st and 3rd to 6th known data sequences are spaced
apart by 16 segments.
[00344]
The signaling information that is to be inserted in
the signaling information area is FEC-encoded by the
signaling encoder 304, thereby inputted to the group
formatter 303. The signaling information may include a
transmission parameter which is included in the payload
region of an OM packet, and then received to the
demultiplexer 210.
[00345]
The group formatter 303 inserts the signaling
information, which is FEC-encoded and outputted by the
signaling encoder 304, in the signaling information area
within the data group. Herein, the signaling information may
be identified by two different types of signaling channels: a
transmission parameter channel (TPC) and a fast information
channel (FIC).
[00346]
Herein, the TPC data is transmitted through the TPC
and corresponds to signaling information including
transmission parameters, such as RS frame information, RS
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encoding information, FIC information, data group information,
SCCC information, and M/H frame information and so on.
However, the TPC data presented herein is merely exemplary.
And, since the adding or deleting of signaling information
included in the TPC may be easily adjusted and modified by
one skilled in the art, the present invention will, therefore,
not be limited to the examples set forth herein. Also, the
TPC data includes parameters that are mostly used in a
physical layer module. And, since the TPC data are
transmitted without being interleaved, the TPC data may be
accessed by slot unit in the receiving system.
[00347] Furthermore, the FIC data is transmitted through
the FIC and is provided to enable a fast service acquisition
of data receivers, and the FIC data includes cross layer
information between the physical layer and the upper layer(s).
[00348] FIG. 34 illustrates a detailed block diagram of the
signaling encoder 304 according to the present invention.
Referring to FIG. 34, the signaling encoder 304 includes a
TPC encoder 561, an FIC encoder 562, a block interleaver 563,
a multiplexer 564, a signaling randomizer 565, and an
iterative turbo encoder 566.
[00349] The TPC encoder 561 receives 10-bytes of TPC data
and performs (18,10)-RS encoding on the 10-bytes of TPC data,
thereby adding 8 bytes of RS parity data to the 10 bytes of
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TPC data. The 18 bytes of RS-encoded TPC data are outputted
to the multiplexer 564.
[00350]
The FIC encoder 562 receives 37-bytes of FIC data
and performs (51,37)-RS encoding on the 37-bytes of FIC data,
thereby adding 14 bytes of RS parity data to the 37 bytes of
FIC data.
Thereafter, the 51 bytes of RS-encoded FIC data
are inputted to the block interleaver 563, thereby being
interleaved in predetermined block units. Herein, the block
interleaver 563 corresponds to a variable length block
interleaver.
The block interleaver 563 interleaves the FIC
data within each sub-frame in TNoG(column)x51(row) block
units and then outputs the interleaved data to the
multiplexer 564.
Herein, the TNoG corresponds to the total
number of data groups being assigned to a sub-frame.
The
block interleaver 563 is synchronized with the first set of
FIC data in each sub-frame.
[00351]
The block interleaver 563 writes 51 bytes of
incoming (or inputted) RS codewords in a row direction (i.e.,
row-by-row) and left-to-right and up-to-down directions and
reads 51 bytes of RS codewords in a column direction (i.e.,
column-by-column) and left-to-right and up-to-down directions,
thereby outputting the RS codewords.
[00352]
The multiplexer 564 multiplexes the RS-encoded TPC
data from the TPC encoder 561 and the block-interleaved FIC
data from the block interleaver 563 along a time axis. Then,
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=
the multiplexer 564 outputs 69 bytes of the multiplexed data
to the signaling randomizer 565.
[00353]
The signaling randomizer 565 randomizes the
multiplexed data and outputs the randomized data to the
iterative turbo encoder 566.
The signaling randomizer 565
may use the same generator polynomial of the randomizer used
for mobile service data. Also, initialization occurs in each
data group.
[00354]
The iterative turbo encoder 566 corresponds to an
inner encoder performing iterative turbo encoding in a PCCC
method on the randomized data (i.e., signaling information
data).
The iterative turbo encoder 566 may include 6 even
component encoders and 6 odd component encoders.
[00355]
FIG. 35 illustrates an example of a syntax
structure of TPC data being inputted to the TPC encoder 561.
[00356]
The TPC data are inserted in the signaling
information area of each data group and then transmitted.
The TPC data may include a sub-frame_number field, a
slot number field, a parade id field, a starting group number
(SGN) field, a number _ of _groups
(NoG) field, a
parade_repetition cycle (PRO) field, an RS_frame mode field,
an RS code mode primary field, an RS code mode secondary
field, an SCCC block mode field, an SCCC outer code mode A
field, an SCCC outer code mode B field,
an
SCCC outer code mode C field, an SCCC outer code mode D field,
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an FIC version field, a parade continuity counter field, and
a TNoG field.
[00357]
The Sub-Frame number field corresponds to the
current Sub-Frame number within the M/H frame, which is
transmitted for M/H frame synchronization. The value of the
Sub-Frame number field may range from 0 to 4.
The
Slot number field indicates the current slot number within
the sub-frame, which is transmitted for M/H frame
synchronization.
Also, the value of the Sub-Frame_number
field may range from 0 to 15. The Parade_id field identifies
the parade to which this group belongs. The value of this
field may be any 7-bit value. Each parade in a M/H
transmission shall have a unique Parade_id field.
[00358]
Communication of the Parade_id between the physical
layer and the management layer may be performed by means of
an Ensemble id field formed by adding one bit to the left of
the Parade_id field.
If the Ensemble id field is used for
the primary Ensemble delivered through this parade, the added
MSB shall be equal to '0'.
Otherwise, if the Ensemble id
field is used for the secondary ensemble, the added MSB shall
be equal to '1'.
Assignment of the Parade_id field values
may occur at a convenient level of the system, usually in the
management layer.
The starting group number (SGN) field
shall be the first Slot number for a parade to which this
group belongs, as determined by Equation 1 (i.e., after the
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Slot numbers for all preceding parades have been
calculated). The SGN and NoG shall be used according to
Equation 1 to obtain the slot numbers to be allocated to a
parade within the sub-frame.
[00359]
The number _ of _Groups (NoG) field shall be the
number of groups in a sub-frame assigned to the parade to
which this group belongs, minus 1, e.g., NoG = 0 implies that
one group is allocated (or assigned) to this parade in a sub-
frame. The value of NoG may range from 0 to 7. This limits
the amount of data that a parade may take from the main
(legacy) service data, and consequently the maximum data that
can be carried by one parade. The slot numbers assigned to
the corresponding Parade can be calculated from SGN and NoG,
using Equation 1.
By taking each parade in sequence, the
specific slots for each parade will be determined, and
consequently the SGN for each succeeding parade. For example,
if for a specific parade SGN = 3 and NoG = 3 (010b for 3-bit
field of NoG), substituting i = 3, 4, and 5 in Equation 1
provides slot numbers 12, 2, and 6.
[00360]
The Parade repetition cycle (PRC) field corresponds
to the cycle time over which the parade is transmitted, minus
1, specified in units of M/H frames, as described in Table 12.
Table 12
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PR
Description
00 This parade shall be transmitted once every M/H
0 frame.
00 This parade shall be transmitted once every 2 M/H
1 frames.
011 This parade shall be transmitted once every 3 M/H
0 frames.
01 This parade shall be transmitted once every 4 M/H
1 frames.
This parade shall be.transmitted once every 5 M/H
0 frames.
10 This parade shall be transmitted once every 6 M/H
1 frames.
11 This parade shall be transmitted once every 7 M/H
0 frames. 1
11
1 Reserved
[00361] For example, if PRC field value is equal to '001',
this indicates that the parade shall be transmitted once
every 2 M/H frame.
[00362] The RS Frame mode field shall be as defined in
Table 1. The RS Frame mode field represents that one parade
transmits one RS frame or two RS frames.
[00363] The RS code mode primary field shall be the RS code
mode for the primary RS frame.
Herein, the
RS code mode primary field is defined in Table 6.
[00364] The RS code mode secondary field shall be the RS
code mode for the secondary RS frame.
Herein, the
RS code mode secondary field is defined in Table 6.
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[00365]
The SCCC Block mode field represents how M/H blocks
within a data group are assigned to SCCC block. The
SCCC Block mode field shall be as defined in Table 7.
[00366]
The SCCC outer code mode A field corresponds to the
SCCC outer code mode for Region A within a data group. The
SCCC outer code mode is defined in Table 8.
[00367]
The SCCC outer code mode B field corresponds to the
SCCC outer code mode for Region B within the data group. The
SCCC outer code mode C field corresponds be the SCCC outer
code mode for Region C within the data group.
And, the
SCCC outer code mode D field corresponds to the SCCC outer
code mode for Region D within the data group.
[00368]
The FTC version field represents a version of FTC
data.
[00369]
The Parade continuity counter field counter may
increase from 0 to 15 and then repeat its cycle.
This
counter shall increment by 1 every (PRC+1) M/H frames.
For
example, as shown in Table 12, PRC = 011 (decimal 3) implies
that Parade continuity counter increases every fourth M/H
frame.
[00370]
The TNoG field may be identical for all sub-frames
in an M/H Frame.
[00371]
However, the information included in the TPC data
presented herein is merely exemplary. And, since the adding
or deleting of information included in the TPC may be easily
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. .
adjusted and modified by one skilled in the art, the present
invention will, therefore, not be limited to the examples set
forth herein.
[00372]
Since the TPC data (excluding the Sub-Frame_number
field and the Slot _number field) for each parade do not
change their values during an M/H frame, the same information
is repeatedly transmitted through all M/H groups belonging to
the corresponding parade during an M/H frame. This allows
very robust and reliable reception of the TPC data. Because
the Sub-Frame number and the Slot number are increasing
counter values, they also are robust due to the transmission
of regularly expected values.
[00373]
Furthermore, the FIC data is provided to enable a
fast service acquisition of data receivers, and the FIC
information includes cross layer information between the
physical layer and the upper layer(s).
[00374]
FIG. 36 illustrates an example of a transmission
scenario of the TPC data and the FIC data. The values of the
Sub-Frame number field, Slot number field, Parade id field,
_ _ Parade_
id
repetition cycle field, and Parade_continuity counter
field may corresponds to the current M/H frame throughout the
sub-frames within a specific M/H frame.
Some of TPC
parameters and FIC data are signaled in advance.
[00375]
The SGN, NoG and all FEC modes may have values
corresponding to the current M/H frame in the first two sub-
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frames.
The SGN, NoG and all FEC modes may have values
corresponding to the frame in which the parade next appears
throughout the 3rd, 4th and 5th sub-frames of the current M/H
frame.
This enables the M/H receivers to receive (or
acquire) the transmission parameters in advance very reliably.
[00376]
For example, when Parade_repetition_cycle = '000',
the values of the 3rd, 4th, and 5th sub-frames of the current
M/H frame correspond to the next M/H frame.
Also, when
Parade repetition cycle = '011', the values of the 3rd, 4th,
and 5th sub-frames of the current M/H frame correspond to the
4th M/H frame and beyond.
[00377]
The FTC _version field and the FIC data field may
have values that apply to the current M/H Frame during the 1st
sub-frame and the 2nd sub-frame, and they shall have values
corresponding to the M/H frame immediately following the
current M/H frame during the 3rd, 4th, and 5th sub-frames of the
current M/H frame.
[00378]
Meanwhile, FTC data being transmitted through the
FTC, i.e., an FTC chunk uses its fast characteristic so as to
deliver mapping information between a mobile service and an
ensemble to the receiving system. At this point, the FTC
chunk is divided into FTC chunk segment units and transmitted
through the FTC. More specifically, the FTC chunk
corresponds to signaling data used for enabling the receiving
system to swiftly find an ensemble that delivers a wanted (or
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CA 02888511 2015-04-20
desired) mobile service and to swiftly receive RS frames of
the corresponding ensemble.
[00379]
FIG. 37 illustrates a syntax structure of an FIC
chunk that maps the relation between a mobile service and an
ensemble through the FIC.
[00380]
Herein, the FIC chunk consists of a 5-byte FIC
chunk header and an FTC chunk payload having variable-length.
[00381]
FIG. 38 illustrates a syntax structure of an FTC
chunk header according to an embodiment of the present
invention.
[00382]
Herein, the FTC chunk header signals a non-backward
compatible major protocol version change in a corresponding
FTC chunk and also signals a backward compatible minor
protocol version change.
Furthermore, the FTC chunk header
also signals the length for an extension of an FIC chunk
header, the length for an extension of an ensemble loop
header, and the length for an extension of a mobile service
loop that can be generated by a minor protocol version change.
[00383]
According to an embodiment of the present invention,
a receiver (or receiving system) that can adopt the
corresponding minor protocol version change may process the
corresponding extension field, whereas a legacy (or
conventional) receiver that cannot adopt the corresponding
minor protocol version change may skip the corresponding
extension field by using each of the corresponding length
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CA 02888511 2015-04-20
. .
information. For example, in case of a receiving system that
can accept the corresponding minor protocol version change,
the directions given in the corresponding extension field may
be known.
Furthermore, the receiving system may perform
operations in accordance with the directions given in the
corresponding extension field.
[00384]
According to an embodiment of the present invention,
a minor protocol version change in the FTC chunk is performed
by inserting additional fields at the respective end portion
of the FIC chunk header, the ensemble loop header, and the
mobile service loop included in the previous minor protocol
version FTC chunk. According to an embodiment of the present
invention, in any other case, or when the length of the
additional fields cannot be expressed (or indicated) by each
extension length within the FTC chunk header, or when a
specific field within the FTC chunk payload is missing (or
cannot be found), or when the number of bits being assigned
to the corresponding field or the definition of the
corresponding field is changed (or altered), the major
protocol version of the corresponding FTC chunk is updated.
[00385]
Also, the FTC chunk header signals whether the data
of a corresponding FTC chink payload carry mapping
information between an ensemble and a mobile service within
the current M/H frame, or whether the data of a corresponding
FTC chink payload carry mapping information between an
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=
ensemble and a mobile service within the next M/H frame.
Furthermore, the FTC chunk header also signals the number of
transport stream IDs of a mobile service through which the
current FTC chunk is being transmitted and the number of
ensembles being transmitted through the corresponding mobile
service.
[00386]
Accordingly, for this, the FTC chunk header may
include an FIC major protocol version field,
an
FIC minor protocol version field,
an
FIC chunk header extension length field,
an
ensemble loop header extension length field,
an
M/H service loop extension length field, a
current next indicator field, a transport stream id field,
and a num ensembles field.
[00387]
The FIC major protocol version field corresponds to
a 2-bit unsigned integer field that represents the major
version level of an FTC chunk syntax. A change in the major
version level shall indicate a change in a non-backward-
compatible level. When the FIC major_protocol_version field
is updated, legacy (or conventional) receivers, which can
process the prior major protocol version of an FIC chunk
protocol, shall avoid processing the FTC chunk.
[00388]
The FIC minor protocol version field corresponds to
a 3-bit unsigned integer field that represents the minor
version level of an FTC chunk syntax. When it is assumed
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that the major version level remains the same, a change in
the minor version level shall indicate a change in a
backward-compatible level. More specifically, when the
FIC minor protocol version field is updated, legacy (or
conventional) receivers, which can process the same major
version of the FIC chunk protocol, may process a portion of
the FIC chunk.
[00389] The FIC Chunk header extension length
field
corresponds to a 3-bit unsigned integer field identifying the
length of FIC chunk header extension bytes, which are
generated by the minor protocol version update of the
corresponding FIC chunk.
Herein, the extension bytes are
appended (or added) at the end of the corresponding FIC chunk
header.
[00390] The ensemble header extension length
field
corresponds to a 3-bit unsigned integer field identifying the
length of the ensemble header extension bytes, which are
generated by the minor protocol version update of the
corresponding FIC chunk.
Herein, the extension bytes are
appended (or added) at the end of the corresponding ensemble
loop header.
[00391]
Also, the M/H service loop extension length field
corresponds to a 4-bit unsigned integer field identifying the
length of the ensemble header extension bytes, which are
generated by the minor protocol version update of the M/H
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,
service loop.
Herein, the extension bytes are appended (or
added) at the end of the corresponding M/H service loop.
[00392]
For example, it is assumed that the FIC chunk
includes 2 ensembles (i.e., ensemble 0 and ensemble 1). More
specifically, it is assumed that two mobile services are
transmitted through ensemble 0, and one mobile service is
transmitted through ensemble 1.
At this point, when the
minor protocol version of the FIC chunk is changed, and the
FIC chunk header is expanded by 1 byte, the
FIC chunk header extension length field is marked as '001'.
_ _
In this case, a 1-byte expansion field
(i.e.,
FIC Chunk header extension bytes field) is added at the end
_
of the FIC chunk header. Also, the legacy receiver skips the
1-byte expansion field, which is added at the end of the FIC
chunk header, without processing the corresponding expansion
field.
[00393]
Additionally, when the ensemble loop header within
the FIC chunk is expanded by 2 bytes, the
ensemble loop _ header _ extension _length field is marked as
'010'. In this case, a 2-byte expansion field (i.e.,
Ensemble loop header extension bytes field) is respectively
_ _ _
added at the end of the ensemble 0 loop header and at the end
of the ensemble 1 loop header. Also, the legacy receiver
skips the 2-byte expansion fields, which are respectively
added at the end of the ensemble 0 loop header and at the end
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of the ensemble 1 loop header, without processing the
corresponding 2-byte expansion fields.
[00394]
Furthermore, when the mobile service loop of the
FIC chunk is expanded by 1 byte,
the
M/H service loop extension length field is marked as '001'.
In this case, a 1-byte expansion
field (i.e.,
M/H service loop extension bytes field) is respectively added
at the end of 2 mobile service loops being transmitted
through ensemble 0 loop and at the end of 1 mobile service
loop being transmitted through the ensemble 1 loop. And, the
legacy receiver skips the 1-byte expansion fields, which are
respectively added at the end of 2 mobile service loops being
transmitted through ensemble 0 loop and at the end of 1
mobile service loop being transmitted through the ensemble 1
loop, without processing the corresponding 1-byte expansion
fields.
[00395]
As described above, when the FIC_minor protocol
version field is changed, a legacy (or conventional) receiver
(i.e., a receiver that cannot adopt the minor protocol
version change in the corresponding FIC chunk) processes the
fields apart from the extension field.
Thereafter, the
legacy receiver uses the FIC_chunk_header_extension_length
field, the ensemble loop header extension length field, and
the M/H service loop extension length field, so as to skip
the corresponding expansion fields without processing the
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corresponding fields. When using a receiving system that can
adopt the corresponding minor protocol version change of the
FTC chunk, each length field is used to process even the
corresponding expansion field.
[00396]
The current next indicator field corresponds to a
1-bit indicator, which, when set to '1', indicates that the
corresponding FTC chunk is currently
applicable.
Alternatively, when the current next indicator field is set
to '0', the current next indicator field indicates that the
corresponding FTC chunk will be applicable for the next M/H
frame. Herein, when the current next_indicator field is set
to '0', the most recent version of the FTC chunk being
transmitted with the current next indicator field set to '1'
shall be currently applicable.
More specifically, when the
current next indicator field value is set to '1', this
indicates that the corresponding FTC chunk transmits the
signaling data of the current M/H frame.
Further, when the
= current next indicator field value is set to '0', this
indicates that the corresponding FTC chunk transmits the
signaling data of the next M/H frame. When reconfiguration
occurs, wherein the mapping information between the ensemble
within the current M/H frame and the mobile service differs
from the ensemble within the next M/H frame and the mobile
service, the M/H frame prior to reconfiguration is referred
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to as the current M/H frame, and the M/H frame following
reconfiguration is referred to as the next M/H frame.
[00397]
The transport_stream_id field corresponds to a 16-
bit unsigned integer number field, which serves as a label
for identifying the corresponding M/H broadcast.
The value
of the corresponding transport stream_id field shall be equal
to the value of the transport stream_id field included in the
program association table (PAT) within the MPEG-2 transport
stream of a main ATSC broadcast.
[00398]
The num ensembles field corresponds to an 8-bit
unsigned integer field, which indicates the number of M/H
ensembles carried through the corresponding physical
transmission channel.
[00399]
FIG. 39 illustrates an exemplary syntax structure
of an FIC chunk payload according to an embodiment of the
present invention.
For each ensemble corresponding to the
num ensembles field value within the FIC chunk header of FIG.
38, the FIC chunk payload includes configuration information
of each ensemble and information on mobile services being
transmitted through each ensemble.
[00400]
The FIC chunk payload consists of an ensemble loop
and a mobile service loop below the ensemble loop. The FIC
chunk payload enables the receiver to determine through which
ensemble a requested (or desired) mobile service is being
transmitted.
(This process is performed via mapping between
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. ,
,
,
the ensemble_id field and the M/H service id field.)
Thus,
_ _
the receiver may receive RS frames belonging to the
corresponding ensemble.
[00401]
In order to do so, the ensemble loop of the FIC
chunk payload may include an ensemble_id field, an
ensemble protocol version field, an SLT ensemble indicator
_ _ _
field, a GAT ensemble indicator field,
an
_
NH service signaling channel version field, and
a
_ _
num_ M/H _services field, which are collectively repeated as
many times as the num_ensembles field value.
The mobile
service loop may include an MH service _id field,
a
multi ensemble service field, an NH service status field, and
_ _ _ _
an SP indicator field, which are collectively repeated as
_
many times as the num M/H_services field.
[00402]
The ensemble_id field corresponds to an 8-bit
unsigned integer field, which indicates a unique identifier
of the corresponding ensemble. For example, the ensemble_id
field may be assigned with values within the range '0x00' to
'0x7F'.
The ensemble_id field group (or associate) the
mobile services with the respective ensemble. Herein, it is
preferable that the value of the ensemble_id field is derived
from the parade_id field carried (or transmitted) through the
TPC data.
If the corresponding ensemble is transmitted
through a primary RS frame, the most significant bit is set
to '0', and the remaining least significant bits are used as
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the parade_id field value of the corresponding parade.
Meanwhile, if the corresponding ensemble is transmitted
through a secondary RS frame, the most significant bit is set
to '0', and the remaining least significant bits are used as
the parade id field value of the corresponding parade.
[00403]
The ensemble protocol version field corresponds to
a 5-bit field, which specifies a version of the corresponding
ensemble structure.
[00404]
The SLT ensemble indicator field is a 1-bit field,
which indicates whether or not the SLT is being transmitted
to the service signaling channel of the corresponding
ensemble. For example, when the SLT ensemble indicator field
value is equal to '1', this may indicate that the SLT is
being transmitted to the service signaling channel.
On the
other hand, when the SLT ensemble indicator field value is
equal to '0', this may indicate that the SLT is not being
transmitted.
[00405]
The GAT ensemble indicator field is also a 1-bit
field, which indicates whether or not the GAT is being
transmitted to the service signaling channel of the
corresponding ensemble. For example, when
the
GAT ensemble indicator field value is equal to '1', this may
indicate that the GAT is being transmitted to the service
signaling channel.
On the other hand, when the
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GAT ensemble indicator field value is equal to '0', this may
indicate that the GAT is not being transmitted.
[00406] The NH service
signaling channel version field
corresponds to a 5-bit field, which indicates a version
number of the service signaling channel of the corresponding
ensemble.
[00407]
The num M/H services field corresponds to an 8-bit
_ _
unsigned integer field, which represents the number of mobile
(i.e., M/H) services carried through the corresponding M/H
ensemble.
[00408]
For example, when the minor protocol version within
the FTC chunk header is changed, and when an extension field
is added to the ensemble loop header, the corresponding
extension field is added immediately after the
num M/H services field.
According to anther embodiment of
_ _
the present invention, if the num_M/H_services field is
included in the mobile service loop, the corresponding
extension field that is to be added in the ensemble loop
header is added immediately after
the
M/H service configuration version field.
[00409]
The M/H service id field of the mobile service loop
corresponds to a 16-bit unsigned integer number, which
identifies the corresponding M/H service. The value (or
number) of the M/H service id field shall be unique within
the mobile (M/H) broadcast.
When an M/H service has
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components in multiple M/H ensembles, the set of IP streams
corresponding to the service in each ensemble shall be
treated as a separate service for signaling purposes, with
the exception that the entries for the corresponding services
in the FIC shall all have the same M/H service id field value.
Thus, the same M/H service id field value may appear in more,
than one num ensembles loop. And, accordingly,
the
M/H service id field shall represent the overall combined
service, thereby maintaining the uniqueness of the
M/H service id field value.
[00410]
The multi ensemble service field is a 2-bit
enumerated field, which indicates whether the corresponding
mobile (M/H) service is transmitted through (or over) one
ensemble, or whether the corresponding mobile (M/H) service
is transmitted through (or over) multiple ensembles. Also,
the value of the multi ensemble service field indicates
whether or not the mobile service is valid (or rendered
meaningfully) only for the mobile service portion being
transmitted through (or over) the corresponding ensemble.
[00411]
The M/H service status field corresponds to a 2-bit
enumerated field, which identifies the status of the
corresponding M/H service. For example, the most significant
bit of the M/H service status field indicates whether the
corresponding M/H service is active (when set to '1') or
inactive (when set to '0').
Furthermore, the least
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significant bit indicates whether the corresponding M/H
service is hidden (when set to '1') or not (when set to '0').
[00412]
The SP indicator field corresponds to a 1-bit field,
which, when set to '1', indicates whether or not service
protection is applied to at least one of the components
required for providing a significant presentation of the
corresponding M/H service.
[00413]
For example, when the minor protocol version of the
FIC chunk is change, and if an expansion field is added to
the mobile service loop, the expansion field is added after
the SP indicator field.
[00414]
Also, the FTC chunk payload may include an
FIC chunk stuffing() field. Stuffing of
the
FTC chunk stuffing() field may exist in an FTC-Chunk, to keep
the boundary of the FTC-Chunk to be aligned with the boundary
of the last FTC-Segment among FTC segments belonging to the
FTC chunk. The length of the stuffing is determined by how
much space is left after parsing through the entire FTC-Chunk
payload preceding the stuffing.
[00415]
At this point, the transmitting system (not shown)
according to the present invention divides the FTC chunk into
multiple FTC segments, thereby outputting the divided FTC
segments to the receiving system in FTC segment units.
The
size of each FTC segment unit is 37 bytes, and each FTC
segment consists of a 2-byte FTC segment header and a 35-byte
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FIC segment payload. More specifically, an FIC chunk, which
is configured of an FIC chunk header and an FIC chunk payload,
is segmented by units of 35 bytes. Also, an FIC segment is
configured by adding a 2-byte FIC segment header in front of
each segmented 35-byte unit.
[00416] According to an embodiment of the present invention,
the length of the FIC chunk payload is variable. Herein, the
length of the FIC chunk varies depending upon the number of
ensembles being transmitted through the corresponding
physical transmission channel and the number of mobile
services included in each ensemble.
[00417]
Also, the FIC chunk payload may include stuffing
data.
In this case, the stuffing data are used for the
boundary alignment of the FIC chunk and the last FIC-Segment,
among FIC segments belonging to the FIC chunk, according to
the embodiment of the present invention.
Accordingly, by
minimizing the length of the stuffing data, unnecessary
wasting of FIC segments can be reduced.
[00418]
At this point, the number of stuffing data bytes
being inserted in the FIC chunk can be calculated by using
Equation 7 below.
Equation 7
The number of stuffing data bytes = 35 - j
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j = (5 + the number of signaling data bytes being inserted
in the FIC chunk payload) mod 35
[00419]
For example, when the added total length of the 5-
byte header within the FIC chunk and signaling data, which is
to be inserted in the payload within the FIC chunk, is equal
to 205 bytes, the payload of the FIC chunk may include 5
bytes of stuffing data because j is equal to 30 in Equation 7.
Also, the length of the FIC chunk payload including the
stuffing data is equal to 210 bytes.
Thereafter, the FIC
chunk is divided into 6 FIC segments, which are then
transmitted. At this point, a segment number is sequentially
assigned to each of the 6 FIC segments divided from the FIC
chunk.
[00420]
Furthermore, the present invention may transmit the
FIC segments divided from a single FIC chunk to a single sub-
frame, or may transmit the divided FIC segments to multiple
sub-frames. If the FIC chunk is divided and transmitted to
multiple sub-frames, signaling data, which are required even
when the amount of data that are to be transmitted through
the FIC chunk is larger than the amount of FIC segments being
transmitted through a single sub-frame (this case corresponds
to when multiple services having very low bit rates are being
executed), may all be transmitted through the FIC chunk.
[00421]
Herein, the FIC segment numbers represent FIC
segment numbers within each FIC chunk, and not the FIC
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segment number within each sub-frame. Thus, the subordinate
relation between the FIC chunk and the sub-frame can be
eliminated, thereby reducing excessive waste of FIC segments.
[00422]
Furthermore, the present invention may add a null
FIC segment.
Despite the repeated transmission of the FIC
chunk, and when stuffing is required in the corresponding M/H
frame, the null FIC segment is used for the purpose of
processing the remaining FIC segments.
For example, it is
assumed that TNoG is equal to '3' and that the FIC chunk is
divided into 2 FIC segments. Herein, when the FIC chunk is
repeatedly transmitted through 5 sub-frames within a single
M/H frame, only 2 FIC segments are transmitted through one of
the 5 sub-frames (e.g., the sub-frame chronologically placed
in the last order).
In this case, one null FIC segment is
assigned to the corresponding sub-frame, thereby being
transmitted. More specifically, the null FIC segment is used
for aligning the boundary of the FIC chunk and the boundary
of the M/H frame. At this point, since the null FIC segment
is not an FIC segment divided from the FIC chunk, an FIC
segment number is not assigned to the null FIC segment.
[00423]
In the present invention, when a single FIC chunk
is divided into a plurality of FIC segments, and when the
divided FIC segments are included in each data group of at
least one sub-frame within the M/H frame, so as to be
transmitted, the corresponding FIC segments are allocated in
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a reversed order starting from the last sub-frame within the
corresponding M/H frame. According to an embodiment of the
present invention, in case a null FIC segment exists, the
null FIC segment is positioned in the sub-frame within the
M/H frame, so that the corresponding null FIC segment can be
transmitted as the last (or final) segment.
[00424] At this point, in order to enable the receiving
system to discard the null FIC segment without having to
process the corresponding null FIC segment, identification
information that can identify (or distinguish) the null FIC
segment is required.
[00425] According to an embodiment of the present invention,
the present invention uses the FIC segment type field within
the header of the null FIC segment as the identification
information for identifying the null FIC segment.
In this
embodiment, the value of the FIC _segment type field within
the null FIC segment header is set to '11', so as to identify
the corresponding null FIC segment. More specifically, when
the FIC segment type field value within the null FIC segment
header is set to '11' and transmitted to the receiving system,
the receiving system may discard the payload of the FIC
segment having the FIC segment type field value set to '11'
without having to process the corresponding FIC segment
payload. Herein, the value '11' is merely an exemplary value
given to facilitate and simplify the understanding of the
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present invention. As long as a pre-arrangement between the
receiving system and the transmitting system is established,
any value that can identify the null FIC segment may be given
to the FIC segment type field.
Therefore, the present
invention will not be limited only to the example set
presented herein.
Furthermore, the identification
information that can identify the null FIC segment may also
be indicated by using another field within the FIC segment
header.
[00426]
FIG. 40 illustrates an exemplary syntax structure
of an FIC segment header according to an embodiment of the
present invention.
[00427]
Herein, the FIC segment header may include an
FIC segment type field, an FIC chunk major protocol version
field, a current next indicator field, an error indicator
field, an FIC segment num field, and an FIC last segment num
field. Each field will now be described as follows.
[00428]
The FIC segment type field corresponds to a 2-bit
field, which, when set to '00' indicates that the
corresponding FIC segment is carrying a portion of an FIC
chunk. Alternatively, when the FIC_segment_type field is set
to '11', the FIC segment type field indicates that the
corresponding FIC segment is a null FIC segment, which
transmits stuffing data. Herein, the remaining values are
reserved for future use.
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[00429] The FIC Chunk major protocol version
field
corresponds to a 2-bit field, which indicates a major
protocol version of the corresponding FIC chunk.
At this
point, the value of the FIC_Chunk_major_protocol_version
field should be the same as the value of the
FIC major protocol version field within the corresponding FIC
chunk header. Since reference may be made to the description
of the FIC chunk header shown in FIG. 38, a detailed
description of the major protocol version of the FIC chunk
syntax will be omitted for simplicity.
[00430]
The current next indicator field corresponds to a
1-bit indicator, which, when set to '1', shall indicate that
the corresponding FIC segment is carrying a portion of the
FIC chunk, which is applicable to the current M/H
frame. Alternatively, when the value of
the
current next indicator field is set to '0',
the
current next indicator field shall indicate
that the
corresponding FIC segment is carrying a portion of the FIC
chunk, which will be applicable for the next M/H frame.
[00431]
The error indicator field corresponds to a 1-bit
field, which indicates whether or not an error has occurred
in the corresponding FIC segment during transmission. Herein,
the error indicator field is set to '1', when an error has
occurred. And, the error indicator field is set to '0', when
an error does not exist (or has not occurred).
More
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specifically, during the process of configuring the FIC
segment, when a non-recovered error exists, the
error indicator field is set to '1'. More specifically, the
error indicator field enables the receiving system to
recognize the existence (or presence) of an error within the
corresponding FIC segment.
[00432]
The FTC segment num field corresponds to a 4-bit
unsigned integer number field, which indicates a number of
the corresponding FTC segment.
For example, if the
corresponding FTC segment is the first FTC segment of the FTC
chunk, the value of the FTC segment num field shall be set to
'0x0'. Also, if the corresponding FTC segment is the second
FTC segment of the FTC chunk, the value of the
FTC segment num field shall be set to '0x1'.
More
specifically, the FTC segment num field shall be incremented
by one with each additional FIC segment in the FTC chunk.
Herein, if the FTC chunk is divided into 4 FTC segments, the
FTC segment num field value of the last FTC segment within
the FTC chunk will be indicated as '0x3'.
[00433]
The FTC last segment num field corresponds to a 4-
bit unsigned integer number field, which indicates the number
of the last FTC segment (i.e., the FTC segment having the
highest FTC segment num field value) within a complete FTC
chunk.
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CA 02888511 2015-04-20
[00434]
In the conventional method, FIC segment numbers are
sequentially assigned (or allocated) for each FIC segment
within one sub-frame. Therefore, in this case, the last PIC
segment number always matches with the TNoG (i.e., the last
FIC segment number is always equal to the TNoG).
However,
when using the FIC number assignment method according to the
present invention, the last FIC segment number may not always
match with the TNoG. More specifically, the last FIC segment
number may match with the TNoG, or the last FIC segment
number may not match with the TNoG.
The TNoG represents a
total number of data groups that are allocated (or assigned)
to a single sub-frame.
For example, when the TNoG is equal
to '6', and when the FIC chunk is divided into 8 FIC segments,
the TNoG is equal to '6', and the last FIC segment number is
'8'.
[00435]
According to another embodiment of the present
invention, the null FIC segment may be identified by using
the value of the FIC segment num field within the FIC segment
header. More specifically, since an FIC segment number is
not assigned to the null FIC segment, the transmitting system
allocates null data to the FIC segment num field value of the
null FIC segment, and the receiving system may allow the FIC
segment having null data assigned to the FIC segment num
field value to be recognized as the null FIC segment. Herein,
instead of the null data, data pre-arranged by the receiving
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system and the transmitting system may be assigned to the
FTC segment num field value, instead of the null data.
[00436]
As described above, the FIC chunk is divided into a
plurality of FTC segments, thereby being transmitted through
a single sub-frame or being transmitted through multiple sub-
frames. Also, FTC segments divided from a single FTC chunk
may be transmitted through a single sub-frame, or FTC
segments divided from multiple single FTC chunks may be
transmitted through a single sub-frame. At this point, the
number assigned to each FTC segment corresponds to a number
within the corresponding FTC chunk (i.e., the FIC_seg_number
value), and not the number within the corresponding sub-frame.
Also, the null FTC segment may be transmitted for aligning
the boundary of the M/H frame and the boundary of the FTC
chunk. At this point, an FTC segment number is not assigned
to the null FTC segment.
[00437]
As described above, one FTC chunk may be
transmitted through multiple sub-frames, or multiple FTC
chunks may be transmitted through a single sub-frame.
However, according to the embodiment of the present invention,
the FTC segments are interleaved and transmitted in sub-frame
units.
[00438]
Meanwhile, FIG. 41 illustrates an exemplary
structure of a bit stream syntax of an SMT section which is
included in the RS frame and then transmitted.
Herein, the
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CA 02888511 2015-04-20
SMT section is configured in an MPEG-2 private section format
for simplicity.
However, the SMT section data may be
configured in any possible format.
[00439]
The SMT may provide access information of mobile
services within an ensemble including the SMT. Also, the SMT
may provide information required for the rendering of mobile
services.
Furthermore, the SMT may include at least one or
more descriptors. Herein, other additional
(or
supplementary) information may be described by the
descriptor.
[00440]
At this point, the service signaling channel that
transmits the SMT may further include another signaling table
(e.g., GAT) in addition to the SMT.
[00441]
Herein, according to the embodiment of the present
invention, IP datagrams of the service signaling channel have
the same well-known destination IP address and the same well-
known destination UDP port number.
Therefore, the SMT
included in the service signaling data is distinguished (or
identified) by a table identifier.
More specifically, the
table identifier may correspond to a table id existing in the
corresponding table or in a header of the corresponding table
section.
And, when required, the table identifier may
further refer to a table _ id _extension field, so as to perform
the identification process.
Exemplary fields that can be
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CA 02888511 2015-04-20
transmitted through the SMT section will now be described in
detail.
[00442] A
table id field is an 8-bit table identifier,
which may be set up as an identifier for identifying the SMT.
[00443] A
section_syntax_indicator field corresponds to an
indicator defining the section format of the SMT.
For
example, the section syntax_indicator field shall be set to
'0' to always indicate that this table is derived from the
"short" form of the MPEG-2 private section table format may
correspond to MPEG long-form syntax.
[00444] A
private indicator field is a 1-bit field, which
indicates whether or not the SMT follows (or is in accordance
with) a private section.
[00445] A
section length field is a 12-bit field, which
specifies the section length of the remaining SMT data bytes
immediately following the section length field.
[00446] A
table id extension field corresponds to a table-
_ table_
extension
16-bit field. Herein, the table_id_extension field
corresponds to a logical portion of the table_id field
providing the scope for the remaining fields.
The
table _ id _extension field includes a SMT protocol version
field and an ensemble id field.
[00447]
The SMT protocol version field corresponds to an 8-
but unsigned integer field. Herein,
the
SMT protocol version field indicates a protocol version for
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allowing the corresponding SMT to carry, in a future process,
parameters that may be structure differently from those
defined in the current protocol. Presently, the value of the
SMT protocol version field shall be equal to zero(0) .
Non-
zero values of the SMT protocol version field may be used by
a future version of this standard to indicate structurally
different tables.
[00448] The ensemble id field corresponds to an 8-bit field.
Herein, the ID values associated with the corresponding
ensemble that can be assigned to the ensemble_id field may
range from '0x00' and '0x3F'.
It is preferable that the
value of the ensemble id field is derived from the TPC data
of the parade_id field. When the corresponding ensemble is
transmitted through a primary RS frame, the most significant
bit (MSB) is set to '0', and the remaining 7 bits are used as
the parade_id field value of the corresponding parade.
Meanwhile, when the corresponding ensemble is transmitted
through a primary RS frame, the most significant bit (MSB) is
set to '1', and the remaining 7 bits are used as the
parade_id field value of the corresponding parade.
[00449] A version number field corresponds to a 5-bit field,
which specifies the version number of the SMT.
[00450] A current next indicator field corresponds to a 1-
_
bit field indicating whether or not the SMT section is
currently applicable.
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= -
[00451]
A section number field is an 8-bit field specifying
the number of the current SMT section.
[00452]
A last section number field corresponds to an 8-bit
field that specifies the number of the last section
configuring the corresponding SMT.
[00453]
And, a num MH services field corresponds to an 8-
_ _
bit field, which specifies the number of mobile services in
the corresponding SMT section.
[00454]
Hereinafter, a number of 'for' loop (also referred
to as mobile (M/H) service loop) statements equivalent to the
number of mobile services corresponding to the
num MH services field is performed so as to provide signaling
_ _
information on multiple mobile services. More specifically,
signaling information of the corresponding mobile service is
indicated for each mobile service that is included in the SMT
section.
Herein, the following field information
corresponding to each mobile service may be provided as
described below.
[00455]
An NH service id field corresponds to a 16-bit
unsigned integer number, which can uniquely identify the
corresponding mobile service within the scope of the
corresponding SMT section.
[00456]
A multi ensemble service field corresponds to a 2-
_
bit field, which indicates whether the corresponding mobile
service is transmitted through one or more ensembles. Since
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the multi ensemble service field has the same meaning as the
multi ensemble service field included in the FTC chunk,
detailed description of the same will be omitted for
simplicity.
[00457]
An NH service status field corresponds to a 2-bit
field, which can identify the status of the corresponding
mobile service.
Herein, the MSB indicates whether the
corresponding mobile service is active ('1') or whether the
corresponding mobile service is inactive ('0').
Also, the
LSB indicates whether the corresponding mobile service is
hidden ('1') or not hidden ('0').
[00458]
An SP indicator field corresponds to a 1-bit field,
which specifies service protection status of the
corresponding mobile service.
If the SP indicator field is
set to '1', then service protection is applied to at least
one of the components needed to provide a meaningful
presentation of the corresponding service.
[00459] A
short NH service name length field corresponds to
_ _
a 3-bit field, which indicates the length of a short service
name described in a short service name field in byte-length
units.
[00460]
The short NH service name field indicates the short
_ _
name of the corresponding mobile service.
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. .
[00461]
An MH service category field is a 6-bit field,
which identifies the type category of the corresponding
mobile service.
[00462] A num components field corresponds to a 5-bit field,
which specifies the number of IP stream components in the
corresponding mobile service.
[00463]
An IP version flag field corresponds to a 1-bit
_ _
indicator, which when set to '0' indicates that a
source IP address field, an MH service destination IP address
_ _ _ _ P_
address
and a component destination IP address
field
correspond to IPv4 addresses.
The value of '1' for the
IP version flag field is reserved for any possible future
_
indication that the source IP address field,
the
NH service destination IP address field, and
the
_ _ _
component destination IP address field correspond to IPv6
addresses.
However, the usage of IPv6 addressing is
currently undefined.
[00464]
A source IP address flag corresponds to a 1-bit
Boolean flag, which indicates, when set, that a source IP
address value for the corresponding service exists (or is
present) so as to indicate a source specific multicast.
[00465] An MH service destination IP address flag
_ _ _ _
corresponds to a 1-bit, which indicates, when set, that the
corresponding IP stream component is transmitted through an
IP datagram having a destination IP address different from
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that of the NH service destination IP address
field.
_ _
Therefore, when the NH service destination IP address flag is
_ _
set, the receiving system may use
the
component_destination_IP_address as
the
destination IP address in order to access the corresponding
IP stream component.
Furthermore, the receiving system
ignores (or disregards) the NH service destination IP address
field within the mobile service loop.
[00466]
The source IP address field corresponds to a 32-bit
_ _
field or a 128-bit field. When the source IP address flag is
_ _
set to '1', the source IP address field is required to be
interpreted (or analyzed). However, when
the
source IP address flag is set to '0', the source IP address
_ _
field is not required to be interpreted (or analyzed). When
the source IP address flagis set to '1', and when the
_ _
IP version flag field is set to '0', the corresponding field
indicates that the source IP address field indicates a 32-bit
_ _
IPv4 address specifying the corresponding mobile service
source.
Alternatively, if the IP version flag field is set
to '1', the source IP address field indicates a 32-bit IPv6
address specifying the corresponding mobile service source.
[00467] The NH service destination IP address
field
_ _
corresponds to a 32-bit field or a 128-bit field. When the
NH service destination IP address flag field is set to '1',
_ _
the NH service destination IP address flag is required to be
_ _
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. .
interpreted (or analyzed). However, when the
NH service destination IP address flag is set to '0', the
_ _ _
NH service destination IP address flag is not required to be
_ _ _ _
interpreted (or analyzed). Herein, if
the
NH service destination IP address flag is set to '1', and if
_ _ _ _
the IP version flag field is set to '0',
the
_ _
NH service destination IP address field indicates a 32-bit
_ _
destination IPv4 address for the corresponding mobile service.
[00468] Alternatively, if the
NH service destination IP address flag is set to '1', and if
_ _ _ _
the IP version flag field is set to '1',
the
_ _
NH service destination IP address field indicates a 64-bit
_ _ _ _
destination IPv6 address for the corresponding mobile service.
In case the corresponding MH_service_destination_IP address
field cannot be interpreted,
the
component_destination_IP_address field within a component
loop shall be interpreted. And, in this case, the receiving
system shall use the component_destination_IP_address in
order to access the IP stream component.
[00469]
Meanwhile, the SMT according to the embodiment of
the present invention provides information on multiple
components using the 'for' loop statement.
Hereinafter, a
number of 'for' loop (also referred to as component loop)
statements equivalent to the number of components
corresponding to the num_component field value is performed
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. .
so as to provide access information on multiple components.
More specifically, access information of each component
included in the corresponding mobile service is provided. In
this case, the following field information on each component
may be provided as described below.
[00470]
A component_source_IP address_flag field is a 1-bit
field (or a 1-boit Boolean flag), which indicates, when set
to '1', that the component_source_IP_address field is present
for this component.
[00471]
More specifically, a mobile service may include
diverse types of components, for example, a mobile service
may include an audio component, or a mobile service may
include a video component, or a mobile service may include a
FLUTE component.
[00472] At this point, when
the
component source IP_address_flag field is set to '1', this
signifies that the component source IP address field exists,
and this field indicates a source IP address of an IP
datagram carrying the corresponding component.
[00473] For example, when
the
component source_IP_address_flag field of the FLUTE component
is set to 'I', the component_source IP_address
field
indicates the source IP address of the IP datagram carrying
the FLUTE component.
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[00474] According to an embodiment of the present invention,
in case a service source IP address field within a mobile
_ _
service loop and a component_source_IP_address within a
component loop both exist, yet if the field values are
different from one another, the source IP address of the IP
datagram of the corresponding component is acquired from the
component source_IP_address field.
More specifically, the
service source IP address field within the mobile service
_ _
loop is disregarded.
[00475]
According to another embodiment of the present
invention, in case the service source IP address field exists
and the component source IP address field does not exist, the
source IP address of the IP datagram of the corresponding
component is acquired from the service source_IP_address
field. And, in the opposite case, i.e., in case the
service source IP address field does not exists and the
_ _
component source IP address field exists, the source IP
address of the IP datagram of the corresponding component is
acquired from the component source IP_address field.
[00476]
As described above, in the present invention, the
component source IP address field exists when
the
component source IP address flag field value is equal to '1'.
And, according to an embodiment of the present invention,
when the component source IP address field exists, the source
IP address of the IP datagram of the corresponding component
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is identical to the component source_IP_address field value.
And, according to another embodiment of the present invention,
in case the component_source_IP_address field does not exist,
the source IP address of the IP datagram of the corresponding
component is identical to the service source IP address field
value.
[00477]
And, according to another embodiment of the present
invention, in case the service source IP address field and
the component source IP address field do not exist, the
source IP address is not used when acquiring the IP datagram
of the corresponding component.
[00478]
If it is assumed that the corresponding component
is a FLUTE component, in order to acquire an IP datagram of
the FLUTE component, transport session identifier (TSI)
information of a FLUTE session transmitting the FLUTE
component is further required. According to an embodiment of
the present invention, the TSI is acquired from a
component_data() having the component_type field value of 38
within the component descriptor().
More specifically, FIG.
43 shows an example of a bitstream syntax structure of a
component data() having the component type field value of 38
within the component descriptor().
[00479]
An essential component indicator field is a 1-bit
field, which indicates that the corresponding component is an
essential component for the mobile service, when the
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essential component indicator field value is set to '1'.
Otherwise, the essential component indicator field indicates
that the corresponding component is an optional component.
For example, in case of a basic layer audio stream and video
stream, the essential component indicator field value is set
to '1'. And, in case of the enhanced layer video stream, the
essential component indicator field value is set to '0'.
[00480] A component
destination_IP_address_flag field
corresponds to a 1-bit Boolean flag.
When the
component_destination_IP address flag field is set to '1',
this indicates that a component destination IP address exists
_ _
for the corresponding component.
[00481] A
port num count field corresponds to a 6-bit field,
which indicates a UDP port number associated with the
corresponding UDP/IP stream component.
Herein, the
destination UDP Port number value is increased by 1 starting
from a destination UDP port num field value.
The
_ _
destination UDP port num field corresponds to a 16-bit field,
_ _
which indicates a destination UDP port number for the
corresponding IP stream component.
[00482] A
component source_IP_address field corresponds to
a 32-bit or 128-bit field, which exists when the value of the
component source_IP_address_flag field is equal to '1'.
At
this point, in case the IP_version flag field is set to '0',
the component_source_IP_address field indicates a 32-bit
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source IPv4 address for the corresponding IP stream component.
Also, in case the IP version flag field is set to '1', the
component source_IP_address field indicates a 128-bit source
IPv6 address for the corresponding IP stream component.
[00483]
According to an embodiment of the present invention,
in case the component source_IP_address field exists, the
source IP address of an IP datagram of the corresponding
component is acquired from the component source IP address
field.
[00484] A component_destination_IP_address
field
corresponds to a 32-bit field or a 128-bit field.
When the
IP version flag field is set to '0',
the
component destination IP address field indicates a 32-bit
destination IPv4 address for the corresponding IP stream
component.
Furthermore, when the IP version flag field is
set to '1',
the component destination IP_address field
indicates a 128-bit destination IPv6 address for the
corresponding IP stream component.
When this field is
present, the destination address of the IP datagrams carrying
the corresponding component of the M/H service shall match
the address in the component_destination_IP address field.
Alternatively, when this field is not present, the
destination address of the IP datagrams carrying the
corresponding component shall match the address in the
M/H service destination IP address field.
The conditional
_ _
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use of the 128 bit-long address version of this field is to
facilitate possible future usage of the IPv6, although the
usage of the IPv6 is currently undefined.
[00485] A
num component level descriptors field corresponds
to a 4-bit field, indicating a number of descriptors
providing additional information on the component level.
[00486] A number of
component level descriptor()
corresponding to the value of
the
num component level descriptors field is included in the
component loop, so as to provide additional (or supplemental)
information on the corresponding component.
[00487] A num NH service
level descriptors field
_ _
corresponds to a 4-bit field indicating a number of
descriptors providing additional information of the
corresponding mobile service level.
[00488] A number of
service level descriptor()
corresponding to the value of
the
num NH service level descriptors field is included in the
_ _
mobile service loop, so as to provide additional (or
supplemental) information on the mobile service.
[00489] A
num ensemble level descriptors field corresponds
to a 4-bit field, which indicates a number of descriptors
providing additional information on ensemble levels.
[00490] Furthermore, a number
of
ensemble level descriptor() corresponding to the value of the
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num ensemble level descriptors field is included in the
ensemble loop, so as to provide additional (or supplemental)
information on the ensemble.
[00491]
FIG. 42 illustrates an embodiment of a bit stream
syntax structure of a component_level descriptors(). The
component descriptor() is used as one of the component level
descriptor component level_descriptors()
of the NST and
describes additional signaling information of
the
corresponding component.
[00492]
The following is a description of each field of the
component_descriptor().
[00493]
In FIG. 42, a descriptor tag field (8-bit) is a
descriptor identifier and it can be set as an identifier that
identifies the component descriptor().
[00494]
A descriptor length field (8-bit) describes the
remaining length of the descriptor starting after the
descriptor_length field and to the end of this descriptor, in
bytes.
[00495]
A component_type field (7-bit) shall identify the
encoding format of the component. The value may be any of the
values assigned by IANA for the payload type of an RTP/AVP
stream, or it may be any of the values assigned by ATSC, or it
may be a "dynamic value" in the range 96-127. For components
consisting of media carried via RTP, the value of this field
shall match the value in the payload type field in the RTP
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header of the IP stream carrying this component. Note that
additional values of the component_type field in the range of
43-71 can be defined in future versions of this standard.
[00496]
A component_encryption_flag (1-bit) informs whether
the corresponding component is encrypted or not.
[00497] A Num STKM streams field (8-bit)
indicates the
number STKM streams if component encryption flag has been
encrypted. (The num_STKM_streams field (8-bit) is an8-bit
unsigned integer field that shall identify the number of STKM
streams associated with this component.
[00498]
A STKIM stream id field (8-bit) is repeated as much
as the field value of Num STKM streams and indicates a value
that identifies a SKTM stream that can acquire a key required
for decryption.
[00499] An NRT component data (component_type)
element
provides the encoding parameters and/or other parameters
necessary for rendering this component. The structure of the
component data is determined by the value of component_type
field.
[00500]
For example, if the component_type field value is 35
then NRT component data (component_type)
field provides
component data for H.264/AVC video stream.
[00501]
In another example, if the component_type field
value is 38 then NRT component data (component_type) field
provides data for FLUTE file delivery as shown in FIG. 43.
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. ,
[00502] One NRT service can be included in multiple FLUTE
sessions. Thus, one NRT service may be configured with
plurality of FLUTE sessions. Each FLUTE session may be
signaled using NRT component data() as shown in FIG. 43.
[00503] FIG. 43 illustrates an example of the bit stream
syntax structure of NRT_component_data() that provides data
for FLUTE file delivery according to the present invention.
The following explains each field in the NRT_component_data().
[00504] A TSI field (16-bit unsigned integer) shall be the
Transport Session Identifier (TSI) of FLUTE session.
[00505] A session start time field (16-bit) indicates the
_ _
start time of the FLUTE session. If the field values are all
'0', then it can be interpreted that the FLUTE session has
already begun.
[00506] A session end time field (16-bit) indicates the end
_ _
time of the FLUTE session. If the field values are all '0,'
then it can be interpreted that the FLUTE session continues
for unlimited amount of time.
[00507] A tias bandwidth _indicator field (1-bit) flags the
inclusion of TIAS bandwidth information. This bit shall be set
to '1' to indicate the TIAS bandwidth field is present, and it
shall be set to '0' to indicate the TIAS bandwidth field is
absent.
[00508] An as _ bandwidth _indicator field (1-bit) flags the
inclusion of AS bandwidth information. This bit shall be set
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,
to '1' to indicate the AS bandwidth field is present, and it
shall be set to '0' to indicate the AS bandwidth field is
absent.
[00509] A FEC OTI indicator field (1-bit) indicates whether
_ _
FEC Object Transmission Information is provided.
[00510] A tias bandwidth field (16-bit) exists when the
_
as bandwidth indicator field value is set to '1' and it
indicates the maximum bandwidth. Also, it shall be one one-
thousandth of the Transport Independent Application Specific
maximum bandwidth as defined in RFC 3890, rounded up to the
next highest integer if necessary. This gives the TIAS
bandwidth in kilobits per second.
[00511] An as _bandwidth field (16-bit) exists when the
as bandwidth indicator field value is set to '1' and it
indicates the maximum AS bandwidth. Also, this value shall be
the Application Specific maximum bandwidth as defined in RFC
4566. This gives the AS bandwidth in kilobits per second.
[00512] A FEC encoding id field exits when
the
_
FEC OTI indicator field value is set to '1' and indicates FEC
_ _
ID used in corresponding FLUTE session. (FEC encoding ID used
in this FLUTE session, as defined in RFC 3926).
[00513] A FEC _instance id field exists when
the
FEC _ OTI _indicator field value is set to '1' and indicates FEC
instance ID used in the corresponding FLUTE session. (FEC
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instance ID used in this FLUTE session, as defined in RFC
3926).
[00514] The information necessary to receive FLUTE session
is provided by signaling the parameters through the
NRT component data() of the component descriptor() within the
component loop.
[00515] In other words, according to the time information
set by the session start time field and the session_end time
field, the corresponding FLUTE session is opened and files
configuring mobile service (or service guide information) and
an FDT (File Description Table) that describes the signaling
information of the files.
[00516] Meanwhile, the receiving system may turn the power on
only during a slot to which the data group of the designated
(or desired) parade is assigned, and the receiving system may
turn the power off during the remaining slots, thereby
reducing power consumption of the receiving system.
Such
characteristic is particularly useful in portable or mobile
receivers, which require low power consumption. For example,
it is assumed that data groups of a 1st parade with NOG-3, a
2nd parade with NOG=2, and a 3rd parade with NOG=3 are assigned
to one M/H frame, as shown in FIG. 44.
It is also assumed
that the user has selected a mobile service included in the
1st parade using the keypad provided on the remote controller
or terminal.
In this case, the receiving system turns the
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power on only during a slot that data groups of the lst parade
is assigned, as shown in FIG. 44, and turns the power off
during the remaining slots, thereby reducing power
consumption, as described above. At this point, the power is
required to be turned on briefly earlier than the slot to
which the actual designated data group is assigned (or
allocated).
This is to enable the tuner or demodulator to
converge in advance.
Assignment of Known Data (or Training Signal)
[00517] In addition to the payload data, the M/H transmission
system inserts long and regularly spaced training sequences
into each group. The regularity is an especially useful
feature since it provides the greatest possible benefit for a
given number of training symbols in high-Doppler rate
conditions. The length of the training sequences is also
chosen to allow fast acquisition of the channel during
bursted power-saving operation of the demodulator.
Each
group contains 6 training sequences. The training sequences
are specified before trellis-encoding.
The training
sequences are then trellis-encoded and these trellis-encoded
sequences also are known sequences.
This is because the
trellis encoder memories are initialized to pre-determined
values at the beginning of each sequence. The form of the 6
training sequences at the byte level (before trellis-
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encoding) is shown in FIG. 45.
This is the arrangement of
the training sequence at the group formatter 303.
[00518] The 1st training sequence is located at the last 2
segments of the 3rd
M/H block (B3). The 2nd training sequence
may be inserted at the 2 'land 3rd segments of the 4th M/H block
(B4). The 2nd training sequence is next to the signaling area,
as shown in FIG. 5.
Then, the 3rd training sequence, the 4th
training sequence, the 5th training sequence, and the 6th
training sequence may be placed at the last 2 segments of the
4th, 5th, 6th, and 7th M/H blocks (B4, B5, B6, and B7),
respectively. As shown in FIG. 45, the l't training sequence,
the 3rd training sequence, the 4th training sequence, the 5th
training sequence, and the 6th training sequence are spaced 16
segments apart from one another.
Referring to FIG. 45, the
dotted area indicates trellis initialization data bytes, the
lined area indicates training data bytes, and the white area
includes other bytes such as the FEC-coded M/H service data
bytes, FEC-coded signaling data, main service data bytes, RS
parity data bytes (for backwards compatibility with legacy
ATSC receivers) and/or dummy data bytes.
[00519] FIG. 46 illustrates the training sequences (at the
symbol level) after trellis-encoding by the trellis encoder.
Referring to FIG. 46, the dotted area indicates data segment
sync symbols, the lined area indicates training data symbols,
and the white area includes other symbols, such as FEC-coded
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mobile service data symbols, FEC-coded signaling data, main
service data symbols, RS parity data symbols (for backwards
compatibility with legacy ATSC receivers), dummy data symbols,
trellis initialization data symbols, and/or the first part of
the training sequence data symbols. Due to the intra-segment
interleaving of the trellis encoder, various types of data
symbols will be mixed in the white area.
[00520] After the trellis-encoding process, the last 1416
(=588+828) symbols of the 1st training sequence, the 3rd
training sequence, the 4th training sequence, the 5th training
sequence, and the 6th training sequence commonly share the
same data pattern.
Including the data segment
synchronization symbols in the middle of and after each
sequence, the total length of each common training pattern is
1424 symbols.
The 2nd training sequence has a first 528-
symbol sequence and a second 528-symbol sequence that have
the same data pattern.
More specifically, the 528-symbol
sequence is repeated after the 4-symbol data segment
synchronization signal. At the end of each training sequence,
the memory contents of the twelve modified trellis encoders
shall be set to zero(0).
Receiving System
[00521]
FIG. 47 illustrates a block diagram showing a
general structure of a receiving system according to an
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embodiment of the present invention.
Referring to FIG. 47,
the arrow shown in dotted line indicates a data path, and the
arrow shown in slid line indicates a control signal path.
[00522]
The receiving system according to the present
invention may include a controller 1100, a tuner 1111, a
demodulator 1112, an equalizer 1113, a known sequence
detector (or known data detector) 1114, a block decoder 1115,
a primary Reed-Solomon (RS) frame decoder 1116, a secondary
RS frame decoder 1117, a signaling decoder 1118, and a
baseband operation controller 1119. The receiving system
according to the present invention may further include an FIC
handler 1121, a service manager 1122, a service signaling
handler 1123, and a first storage unit 1124. The receiving
system according to the present invention may further include
a primary RS frame buffer 1131, a secondary RS frame buffer
1132, and a transport packet (TS) handler 1133. The receiving
system according to the present invention may further include
an Internet Protocol (IP) datagram handler 1141, a
descrambler 1142, an User Datagram Protocol (UDP) datagram
handler 1143, a Real-time Transport Protocol/Real-time
Transport Control Protocol (RTP/RTCP) datagram handler 1144,
a Network Time Protocol (NTP) datagram handler 1145, a
service protection stream handler 1146, a second storage unit
1147, an Asynchronous Layered Coding/Layered Coding Transport
(ALC/LCT) stream handler 1148, an Extensible Mark-up Language
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(XML) parser 1150, and a Field Device Tool (FDT) handler 1151.
The receiving system according to the present invention may
further include an Audio/Video (A/V) decoder 1161, a file
decoder 1162, a third storage unit 1163, a middle ware (M/W)
engine 1164, and a Service Guide (SG) handler 1165. The
receiving system according to the present invention may
further include an Electronic Program Guide (EPG) manager
1171, an application manager 1172, and an User Interface (UI)
manager 1173.
[00523]
Herein, for simplicity of the description of the
present invention, the tuner 1111, the demodulator 1112, the
equalizer 1113, the known sequence detector (or known data
detector) 1114, the block decoder 1115, the primary RS frame
decoder 1116, the secondary RS frame decoder 1117, the
signaling decoder 1118, and the baseband operation controller
1119 will be collectively referred to as a baseband processor
1110. The FIC handler 1121, the service manager 1122, the
service signaling handler 1123, and the first storage unit
1124 will be collectively referred to as a service
multiplexer 1120. The primary RS frame buffer 1131, the
secondary RS frame buffer 1132, and the TS handler 1133 will
be collectively referred to as an IP adaptation module 1130.
The IP datagram handler 1141, the descrambler 1142, the UDP
datagram handler 1143, the RTP/RTCP datagram handler 1144,
the NTP datagram handler 1145, the service protection stream
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handler 1146, the second storage unit 1147, the ALC/LCT
stream handler 1148, the XML parser 1150, and the FDT handler
1151 will be collectively referred to as a common IP module
1140. The A/V decoder 1161, the file decoder 1162, the third
storage unit 1163, the M/W engine 1164, and the SG handler
1165 will be collectively referred to as an application
module 1160.
[00524]
The baseband processor 1110 according to the
present invention may further include a main service data
processing unit (not shown) for main service data. Also, the
receiving system may further include a power controller (not
shown) controlling the power supply of the baseband processor
1110.
By performing carrier wave synchronization recovery,
frame synchronization recovery, and channel equalization
using known data transmitted from the transmitting system,
the baseband processor 1110 may enhance the receiving
performance.
Also, by having the baseband processor 1110
turn on the power only in the slot(s) where a data group of a
parade including the requested mobile service is assigned,
the power consumption rate of the receiving system may be
reduced.
[00525]
Meanwhile, in the transmitting system, the
transmitting may insert signaling information (or TPC
information) including a transmission parameter in at least
one of a signaling information region, a field
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synchronization region, a known data region, and a mobile
service data region, and may transmit the processed data.
Accordingly, the baseband processor 1110 may extract the
transmission parameter from at least one of the signaling
information region, the field synchronization region, the
known data region, and the mobile service data region.
[00526]
The transmission parameter may include M/H frame
information, sub frame information, slot information, parade-
related information (e.g., parade ID, parade repetition cycle
period, etc.), data group information within the subframe, RS
frame mode information, RS code mode information, SCCC block
information, SCCC outer code mode information, FIC version
information, and so on.
[00527]
The baseband processor 1110 uses the extracted
transmission parameter to perform block decoding, RS frame
decoding, and so on.
For example, the baseband processor
1110 refers to the SCCC-related information (e.g., SCCC block
information, SCCC outer code mode) within the transmission
parameter, so as to perform block decoding of each region
within the data group, and also refers to RS-relation
information (e.g., RS code mode), so as to perform RS frame
decoding of each region within the data group.
[00528]
The terms used in FIG. 47 are general terms that
are currently being broadly used. However, according to the
advent of new technology, terms deemed to be most appropriate
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by the applicant are also arbitrarily used in the present
invention.
The definition of such terms will be described
clearly and in detail during the description of the
corresponding portion of the present invention.
Therefore,
the terms used in the present invention should be understood
by the significance lying within the terms and not merely by
the term itself.
[00529]
The baseband operation controller 1119 configured
as shown in FIG. 47 controls the operation of each block
included in the baseband processor 1110.
[00530]
By tuning the receiving system to the frequency of
a specific physical channel (or physical transmission channel
(PTC)), the tuner 1111 performs a role enabling the receiving
system to receive main service data, which correspond to
broadcast signals for fixed broadcast receiving systems, and
mobile service data, which correspond to broadcast signals
for mobile broadcast receiving systems. At this point, the
frequency of the tuned specific channel is down-converted to
an intermediate frequency (IF), thereby being outputted to
the demodulator 1112 and the known sequence detector 1114.
The passband digital IF signal being outputted from the tuner
1111 may only include only the main service data or only the
mobile service data or both the main service data and the
mobile service data.
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[00531]
The demodulator 1112 performs self-gain control,
carrier wave recovery, and timing recovery on the passband
digital IF signal being inputted from the tuner 1111, so as
to create a baseband signal.
Then, the dmodulator 1112
outputs the read baseband signal to the equalizer 1113 and
the know sequence detector 1114.
When performing carrier
wave recovery and timing recovery, the demodulator 1112 may
use the known data symbol sequence received from the known
sequence detector 1114), so as to enhance the demodulating
performance.
[00532]
The equalizer 1113 compensates the channel
distortion included in the demodulated signal, thereby
outputting the processed signal to the block decoder 1115.
The equalizer 1113 may enhance the equalizing performance by
using the known data symbol sequence received from the known
sequence detector 1114. Also, the equalizer 1113 may receive
feedback on the decoding result of the block decoder 1113,
thereby enhancing the equalizing performance.
[00533]
The known sequence detector 1114 detects the
position of the known data being inputted by the transmitting
system from the input/output data of the demodulator 1112,
i.e., data prior to being processed with the demodulation
process or data being partially processed with the
demodulation process. Then, along with the detected position
information, the known sequence detector 1114 outputs the
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. .
known data sequence generated from the detected position to
the demodulator 1112, the equalizer 1113, the signaling
decoder 1118, and the baseband operation controller 1119.
Additionally, the known sequence detector 1114 provides the
block decoder 1115 with information enabling the block
decoder 1115 to differentiate mobile service data processed
with additional encoding by the transmitting system from main
service data that are not processed with any additional
encoding.
[00534] If the data channel-equalized by the equalizer 1113
and inputted to the block decoder 1115 correspond to data
processed with both block-encoding of serial concatenated
convolution code (SCCC) method and trellis-encoding by the
transmitting system (i.e., data within the RS frame,
signaling data), the block decoder 1115 may perform trellis-
decoding and block-decoding as inverse processes of the
transmitting system. On the other hand, if the data channel-
equalized by the equalizer 1113 and inputted to the block
decoder 1115 correspond to data processed only with trellis-
encoding and not block-encoding by the transmitting system
(i.e., main service data), the block decoder 1115 may perform
only trellis-decoding.
[00535] The data demodulated by the demodulator 1112 or the
data channel-equalized by the equalizer 1113 are inputted to
the signaling decoder 1118. Also, the known data (or
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sequence) position information detected by the known sequence
detector 1114 is also inputted to the signaling decoder 1118.
[00536]
The signaling decoder 1118 extracts the signaling
information (e.g., TPC data, FIC data) inserted and
transmitted by the transmitting system from the inputted data
and decodes the extracted signaling information. Thereafter,
the signaling decoder 1118 provides the decoded signaling
information to a block requiring such information.
[00537]
More specifically, the signaling decoder 1118
extracts the signaling information (e.g., TPC data and FIC
data) inserted and transmitted by the transmitting system
from the equalized data and decodes the extracted signaling
information, thereby providing the decoded signaling
information to the baseband operation controller 1119, the
known sequence detector 1114, and the power controller.
It
is assumed that the TPC data and FIC data decoded by the
signaling decoder 1118 correspond to data processed with both
block-encoding and trellis-encoding by the transmitting
system.
[00538]
According to an embodiment of the present invention,
the signaling decoder 1118 performs signaling decoding as an
inverse process of the signaling encoder of FIG. 34, so as to
extract the TPC data and FIC data.
For example, the
signaling decoder 1118 performs regressive turbo decoding
using a parallel concatenated convolution code (PCCC) method
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on the data of the signaling information region among the
inputted data.
Then, the signaling decoder 1118 performs
derandomizing on the turbo-decoded signaling data, thereby
separating the FIC data and TPC data from the derandomized
signaling data. Also, the signaling decoder 1118 performs
RS-decoding on the separated TPC data as an inverse process
of the transmitting system, thereby outputting the RS-decoded
TPC data to the baseband operation controller 1119, the known
sequence detector 1114, and the power controller.
[00539]
The TPC data may include a transmission parameter,
which is inserted in the payload region of an ON packet by
the service multiplexer 100 and transmitted to the
transmitter 200.
[00540]
Herein, as shown in FIG. 35, the TPC data may
include RS frame information, SCCC information, M/H frame
information, and so on. The RS frame information may include
RS frame mode information and RS code mode information. The
SCCC information may include SCCC block mode information and
SCCC outer code mode information. The M/H frame information
may include M/H frame index information. Also, the TPC data
may include subframe count information, slot count
information, parade_id information, SGN information, NOG
information, and so on.
[00541]
Furthermore, the signaling decoder 1118 performs
deinterleaving on the separated FIC data in subframe units
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and then performs RS-decoding on the deinterleaved FIC data
as an inverse process of the transmitting system, thereby
outputting the RS-decoded data to the FIC handler 1121. The
transmission unit of the FIC data being deinterleaved and RS-
decoded by the signaling decoder 1118 and being outputted to
the FIC handler 1121 corresponds to FIC segments.
[00542]
At this point, the signaling information region
within the data group may be known by using known data (or
sequence) information outputted from the known sequence
detector 1114.
More specifically, a first known data
sequence (or training sequence) is inserted in the last 2
segments of M/H block B3 within the data group.
And, a
second known data sequence is inserted between the second and
third segments of M/H block B4.
At this point, since the
second known data sequence is inserted after the signaling
information region and received, the signaling decoder 1118
extracts signaling information of the signaling information
region from the data being outputted from the demodulator
1112 or the channel equalizer 1113, thereby decoding the
extracted signaling information.
[00543]
The power controller receives M/H frame-associated
information from the signaling decoder 1118 so as to control
the power of the baseband processor 1110.
The power
controller receives power control information from the
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. .
baseband operation controller 1119, thereby being capable of
controlling the power of the tuner and the demodulator.
[00544] According to an embodiment of the present invention,
the power controller turns on the power of a slot having the
data group of a parade including the mobile service wanted by
the user assigned thereto, so as to receive data, and the
power controller turns power off all of the other slots.
[00545]
For example, it is assumed that data groups of a
first parade having an NOG equal to 3, a second parade having
an NOG equal to 2, and a third parade having an NOG equal to
2 are assigned to a single M/H frame, as shown in FIG. 33.
It is also assumed that the user uses a remote controller or
a keypad provided in a mobile equipment (or user terminal or
equipment) so as to select a mobile service included in the
first parade.
In this case, the power controller turns the
power on in a slot having a data group of the first parade
assigned thereto, as shown in FIG. 44, and the power
controller turns the power off in the remaining sections,
thereby being capable of reducing power consumption. At this
point, the power is required to be turned on slightly earlier
than the slot having a requested actual data group assigned
thereto.
This is to enable the tuner or demodulator to
converge in advance.
Demodulator and Known sequence detector
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[00546] At this point, the transmitting system may receive a
data frame (or VSB frame) including a data group which known
data sequence (or training sequence) is periodically inserted
therein, as shown in FIG. 5. Herein, the data group is
divided into regions A to D, as shown in FIG. 5.
More
specifically, in the example of the present invention, each
region A, B, C, and D are further divided into M/H blocks B4
to B7, M/H blocks B3 and B8, M/H blocks B2 and B9, M/H
blocks Si and B10, respectively.
[00547] Referring to FIG. 45 and FIG. 46, known data sequence
having the same pattern are included in each known data
section that is being periodically inserted.
Herein, the
length of the known data sequence having identical data
patterns may be either equal to or different from the length
of the entire (or total) known data sequence of the
corresponding known data section (or block).
If the two
lengths are different from one another, the length of the
entire known data sequence should be longer than the length
of the known data sequence having identical data patterns.
In this case, the same known data sequences are included in
the entire known data sequence.
[00548] As described above, when the known data are periodically
inserted in-between the mobile service data, the channel
equalizer of the receiving system may use the known data as
training sequences, which may be used as accurate
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discriminant values. According to another embodiment of the
present invention, the channel equalizer estimates a channel
impulse response. Herein, the known data may be used in the
process. According to yet another embodiment of the present
invention, the channel equalizer may use the known data for
updating filter coefficients (i.e.,
equalization
coefficients).
[00549] Meanwhile, when known data sequence having the same
pattern is periodically inserted, each known data sequence
may be used as a guard interval in a channel equalizer
according to the present invention. Herein, the guard
interval prevents interference that occurs between blocks due
to a multiple path channel. This is because the known data
sequence located behind a mobile service data section (i.e.,
data block) may be considered as being copied in front of the
mobile service data section.
[00550] The above-described structure is referred to as a cyclic
prefix.
This structure provides circular convolution in a
time domain between a data block transmitted from the
transmitting system and a channel impulse response.
Accordingly, this facilitates the channel equalizer of the
receiving system to perform channel equalization in a
frequency domain by using a fast fourier transform (FFT) and
an inverse fast fourier transform (IFFT).
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[00551] More specifically, when viewed in the frequency domain,
the data block received by the receiving system is expressed
as a multiplication of the data block and the channel impulse
response.
Therefore, when performing the channel
equalization, by multiplying the inverse of the channel in
the frequency domain, the channel equalization may be
performed more easily.
[00552] The known sequence detector 1114 detects the position of
the known data being periodically inserted and transmitted as
described above.
At the same time, the known sequence
detector 1114 may also estimate initial frequency offset
during the process of detecting known data.
In this case,
the demodulator 1112 may estimate with more accuracy carrier
frequency offset from the information on the known data
position information and initial frequency offset estimation
value, thereby compensating the estimated carrier frequency
offset.
[00553] Meanwhile, when known data is transmitted, as shown in
FIG. 5, the known sequence detector 1114 detects a position
of second known data region by using known data of the second
known data region that the same pattern is repeated twice.
[00554] At this point, since the known sequence detector 1114 is
well-informed of the data group structure, when the position
of the second known data region is detected, the known
sequence detector 1114 can estimate positions of the first,
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third, fourth, fifth, and sixth known data regions of a
corresponding data group by counting symbols or segments
based upon the second known data region position.
If the
corresponding data group is a data group including field
synchronization segment, the known sequence detector 1114 can
estimate the position of the field synchronization segment of
the corresponding data group, which is positioned
chronologically before the second known data region, by
counting symbols or segments based upon the second known data
region position.
[00555] Also, the known sequence detector 1114 may estimate the
known data position information and the field synchronization
position information from the parade including mobile service
selected by a user based on the M/H frame-associated
information outputted from the signaling decoder 1118. At
least one of the estimated known data poison information and
field synchronization information is provided to the
demodulator 1112, the channel equalizer 1113, the signaling
decoder 1118, and the baseband operation controller 1119.
[00556] Also, the known sequence detector 1114 may estimate
initial frequency offset by using known data inserted in the
second known data region (i.e., ACQ known data region). In
this case, the demodulator 1112 may estimate with more
accuracy carrier frequency offset from the information on the
known data position information and initial frequency offset
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estimation value, thereby compensating the estimated carrier
frequency offset.
[00557]
The FIC handler 1121 receives FIC data from the
signaling decoder 1118, so as to extract signaling
information for service acquisition (i.e., mapping
information between an ensemble and a mobile service).
In
order to do so, the FIC handler 1121 may include an FIC
segment buffer, an FIC segment parser, and an FIC chunk
parser.
[00558]
The FIC segment buffer buffers FIC segment groups
being inputted in M/H frame units from the signaling decoder
1118, thereby outputting the buffered FIC segment groups to
the FIC segment parser.
Thereafter, the FIC segment parser
extracts the header of each FIC segment stored in the FIC
segment buffer so as to analyze the extracted headers. Then,
based upon the analyzed result, the FIC segment parser
outputs the payload of the respective FIC segments to the FIC
chunk parser. The FIC chunk parser uses the analyzed result
outputted from the FIC segment parser so as to recover the
FIC chunk data structure from the FIC segment payloads,
thereby analyzing the received FIC chunk data structure.
Subsequently, the FIC chunk parser extracts the signaling
information for service acquisition.
The signaling
information acquired from the FIC chunk parser is outputted
to the service manager 1122.
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[00559]
Meanwhile, the service signaling handler 1123 is
configured of a service signaling buffer and a service
signaling parser, and the service signaling handler 1123
buffers table sections of a service signaling channel being
transmitted from the UDP datagram handler 1143, thereby
analyzing and processing the buffered table sections.
The
signaling information processed by the service signaling
handler 1123 is also outputted to the service manager 1122.
[00560]
More specifically, the service signaling channel
transmits at least one of an SMT, a GAT, an RRT, a CIT, and
an SLT.
At this point, according to an embodiment of the
present invention, access information of the IP datagram
transmitting the service signaling channel corresponds to a
well-known destination IP address and a well-known
destination UDP port number.
Accordingly, each of the IP
datagram handler 1141 and the UDP datagram handler 1143 is
respectively given a well-known destination IP address and a
well-known destination UDP port number, so as to extract an
IP stream transmitting the service signaling channel, i.e.,
the service signaling data, thereby outputting the extracted
data to the service signaling handler 1123.
The service
signaling handler 1123 recovers the SMT of FIG. 41 from the
service signaling data and outputs the recovered SMT to the
service manager 1122.
Furthermore, the service signaling
handler 1123 may further recover at least one of the GAT, the
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RRT, the CIT, and the SLT from the service signaling data and
may output the further recovered table to the service manager
1122.
[00561]
The service manager 1122 uses the signaling
information collected (or gathered) from the FIC handler 1121
and the service signaling handler 1123 so as to configure a
service map, and the service manager 1122 uses the service
guide (SG) collected from the service guide (SG) handler 1165
so as to configure a program guide.
Then, the service
manager 1122 refers to the configured service map and program
guide to control the baseband operation controller 1119 so
that the user can receive the mobile service he (or she)
wishes.
Also, depending upon the user's input, the service
manager 1122 may perform controlling operations enabling the
program guide to be displayed on at least one portion of the
display screen.
[00562]
For example, the service manager 1122 acquires
access information of a mobile service and access information
of a component configuring the mobile service from the SMT.
At this point, when the value of a
component source IP address_flag field included in a
component loop statement of the SMT is set to '1', a source
IP address of an IP datagram delivering the corresponding
component is acquired from the component source IP address
field.
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[00563]
In case a service source IP address field within a
_ _
mobile service loop of the SMT and a
component source IP address field within a component loop of
the SMT both exist, yet in case the value of each field is
different from one another, the present invention acquires
the source IP address of the IP datagram of the corresponding
component from the component source IP address field.
In
other words, the service source IP address field within the
mobile service loop is disregarded. Alternatively, in case
the service source IP address field exists and
the
component_source_IP address field does not exist, the source
IP address of the IP datagram of the corresponding component
is acquired from the service source IP address field.
And,
in the opposite case, i.e., in case
the
component source_IP_address field exists and
the
service source _ IP _address field does not exist, the source IP
address of the IP datagram of the corresponding component is
acquired from the component_source_IP address field.
[00564]
The acquired source IP address of the IP datagram
of the corresponding component may be used when decoding the
IP datagram of the corresponding component.
For example,
according to an embodiment of the present invention, when
decoding the IP datagram of the FLUTE component, the source
IP address acquired from the component source IP address
field is used.
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s,
[00565]
As described above, in the present invention, the
component_source_IP_address field exists when
the
component source IP address flag field value is equal to '1'.
And, according to an embodiment of the present invention,
when the component source_IP_address field exists, the source
IP address of the IP datagram of the corresponding component
is identical to (or matches) the component source IP address
_ _
field value.
According to the embodiment of the present
invention, if the component source IP address field does not
exist, the source IP address of the IP datagram of the
corresponding component is identical to (or matches) the
service source IP address field value.
[00566]
According to yet another embodiment of the present
invention, in case neither of the service source IP address
field and the component_source_IP_address field exists, the
source IP address of the IP datagram of the corresponding
component is not used.
[00567]
When it is assumed that the corresponding component
is a FLUTE component, in order to acquire (or decode) the IP
datagram of the FLUTE component, transport session identifier
(TSI) information of a FLUTE session transmitting the FLUTE
component is further required. According to an embodiment of
the present invention, the TSI is acquired from a
component data() having a component_type field value of '38'
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of the component descriptor component descriptor() within the
component loop of the SMT.
[00568]
The first storage unit 1124 stores the service map
and service guide drawn up by the service manager 1122. Also,
based upon the requests from the service manager 1122 and the
EPG manager 1171, the first storage unit 1124 extracts the
required data, which are then transferred to the service
manager 1122 and/or the EPG manager 1171.
[00569]
The baseband operation controller 1119 receives the
known data place information and TPC data, thereby
transferring M/H frame time information, information
indicating whether or not a data group exists in a selected
parade, place information of known data within a
corresponding data group, power control information, and so
on to each block within the baseband processor 1110.
[00570]
Meanwhile, according to the present invention, the
transmitting system uses RS frames by encoding units. Herein,
the RS frame may be divided into a primary RS frame and a
secondary RS frame. However, according to the embodiment of
the present invention, the primary RS frame and the secondary
RS frame will be divided based upon the level of importance
of the corresponding data.
[00571]
The primary RS frame decoder 1116 receives the data
outputted from the block decoder 1115.
At this point,
according to the embodiment of the present invention, the
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primary RS frame decoder 1116 receives only the mobile
service data that have been Reed-Solomon (RS)-encoded and/or
cyclic redundancy check (CRC)-encoded from the block decoder
1115.
[00572]
Herein, the primary RS frame decoder 1116 receives
only the mobile service data and not the main service data.
The primary RS frame decoder 1116 performs inverse processes
of the primary encoder (410) included in the digital
broadcast transmitting system, thereby correcting errors
existing within the primary RS frame. More specifically, the
primary RS frame decoder 1116 forms a primary RS frame by
grouping a plurality of data groups and, then, correct errors
in primary RS frame units.
In other words, the primary RS
frame decoder 1116 decodes primary RS frames, which are being
transmitted for actual broadcast services.
[00573] A
payload of the primary RS frame decoded by the
primary RS frame decoder 1116 is derandomized and then is
output to the primary RS frame buffer 1131. The primary RS
frame buffer 1131 buffers the primary RS frame payload, and
then configures an M/H TP in each row unit. The M/H TPs of
the primary RS frame outputs to the TP handler 1133.
[00574]
Additionally, the secondary RS frame decoder 1117
receives the data outputted from the block decoder 1115. At
this point, according to the embodiment of the present
invention, the secondary RS frame decoder 1117 receives only
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the mobile service data that have been RS-encoded and/or CRC-
encoded from the block decoder 1115.
Herein, the secondary
RS frame decoder 1117 receives only the mobile service data
and not the main service data. The secondary RS frame decoder
1117 performs inverse processes of the secondary encoder
(420) included in the digital broadcast transmitting system,
thereby correcting errors existing within the secondary RS
frame.
More specifically, the secondary RS frame decoder
1117 forms a secondary RS frame by grouping a plurality of
data groups and, then, correct errors in secondary RS frame
units.
In other words, the secondary RS frame decoder 1117
decodes secondary RS frames, which are being transmitted for
mobile audio service data, mobile video service data, guide
data, and so on. A payload of the secondary RS frame decoded
by the secondary RS frame decoder 1117 is derandomized and
then is output to the secondary RS frame buffer 1132. The
secondary RS frame buffer 1132 buffers the secondary RS frame
payload, and then configures an M/H TP in each row unit. The
M/H TPs of the secondary RS frame outputs to the TP handler
1133.
[00575]
The TP handler 1133 consists of a TP buffer and a
TP parser. The TP handler 1133 buffers the M/H TPs inputted
from the primary RS frame buffer 1131 and the secondary RS
frame buffer 1132, and then extracts and analyzes each header
of the buffered M/H TPs, thereby recovering IP datagram from
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each payload of the corresponding M/H TPs. The recovered IP
datagram is outputted to the IP datagram handler 1141.
[00576] The IP datagram handler 1141 consists of an IP
datagram buffer and an IP datagram parser. The IP datagram
handler 1141 buffers the IP datagram delivered from the TP
handler 1133, and then extracts and analyzes a header of the
buffered IP datagram, thereby recovering UDP datagram from a
payload of the corresponding IP datagram. The recovered UDP
datagram is outputted to the UDP datagram handler 1143.
[00577] If the UDP datagram is scrambled, the scrambled UDP
datagram is descrambled by the descrambler 1142, and the
descrambled UDP datagram is outputted to the UDP datagram
handler 1143. For example, when the UDP datagram among the
received IP datagram is scrambled, the descrambler 1142
descrambles the UDP datagram by inputting an encryption key
and so on from the service protection stream handler 1146,
and outputs the descrambled UDP datagram to the UDP datagram
handler 1143.
[00578] The UDP datagram handler 1143 consists of an UDP
datagram buffer and an UDP datagram parser. The UDP datagram
handler 1143 buffers the UDP datagram delivered from the IP
datagram handler 1141 or the descrambler 1142, and then
extracts and analyzes a header of the buffered UDP datagram,
thereby recovering data transmitted through a payload of the
corresponding UDP datagram. If the recovered data is an
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RTP/RTCP datagram, the recovered data is outputted to the
RTP/RTCP datagram handler 1144. If the recovered data is also
an NTP datagram, the recovered data is outputted to the NTP
datagram handler 1145. Furthermore, if the recovered data is
a service protection stream, the recovered data is outputted
to the service protection stream handler 1146. And, if the
recovered data is an ALC/LCT stream, the recovered data is
outputted to the ALC/LCT steam handler 1148.
[00579] The RTP/RTCP datagram handler 1144 consists of an
RTP/RTCP datagram buffer and an RTP/RTCP datagram parser. The
RTP/RTCP datagram handler 1144 buffers the data of RTP/RTCP
structure outputted from the UDP datagram handler 1143, and
then extracts A/V stream from the buffered data, thereby
outputting the extracted A/V stream to the A/V decoder 1161.
[00580] The A/V decoder 1161 decodes the audio and video
streams outputted from the RTP/RTCP datagram handler 1144
using audio and video decoding algorithms, respectively. The
decoded audio and video data is outputted to the presentation
manager 1170. Herein, at least one of an AC-3 decoding
algorithm, an MPEG 2 audio decoding algorithm, an MPEG 4
audio decoding algorithm, an AAC decoding algorithm, an AAC+
decoding algorithm, an HE AAC decoding algorithm, an AAC SBR
decoding algorithm, an MPEG surround decoding algorithm, and
a BSAC decoding algorithm can be used as the audio decoding
algorithm and at least one of an MPEG 2 video decoding
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=
algorithm, an MPEG 4 video decoding algorithm, an H.264
decoding algorithm, an SVC decoding algorithm, and a VC-1
decoding algorithm can be used as the audio decoding
algorithm.
[00581]
The NTP datagram handler 1145 consists of an NTP
datagram buffer and an NTP datagram parser. The NTP datagram
handler 1145 buffers data having an NTP structure, the data
being outputted from the UDP datagram handler 1143.
Then,
the NTP datagram handler 1145 extracts an NTP stream from the
buffered data.
Thereafter, the extracted NTP stream is
outputted to the A/V decoder 1161 so as to be decoded.
[00582]
The service protection stream handler 1146 may
further include a service protection stream buffer. Herein,
the service protection stream handler 1146 buffers data
designated (or required) for service protection, the data
being outputted from the UDP datagram handler 1143.
Subsequently, the service protection stream handler 1146
extracts information required for descrambling from the
extracted data.
The information required for descrambling
includes a key value, such as SKTM and LKTM. The information
for descrambling is stored in the second storage unit 1147,
and, when required, the information for descrambling is
outputted to the descrambler 1142.
[00583]
The ALC/LCT stream handler 1148 consists of an
ALC/LCT stream buffer and an ALC/LCT stream parser. And, the
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ALC/LCT stream handler 1148 buffers data having an ALC/LCT
structure, the data being outputted from the UDP datagram
handler 1143. Then, the ALC/LCT stream handler 1148 analyzes
a header and a header expansion of an ALC/LCT session from
the buffered data.
Based upon the analysis result of the
header and header expansion of the ALC/LCT session, when the
data being transmitted to the ALC/LCT session correspond to
an XML structure, the corresponding data are outputted to an
XML parser 1150.
Alternatively, when the data being
transmitted to the ALC/LCT session correspond to a file
structure, the corresponding data are outputted to a file
decoder 1162.
At this point, when the data that are being
transmitted to the ALC/LCT session are compressed, the
compressed data are decompressed by a decompressor 1149,
thereby being outputted to the XML parser 1150 or the file
decoder 1162.
[00584]
The XML parser 1150 analyses the XML data being
transmitted through the ALC/LCT session.
Then, when the
analyzed data correspond to data designated to a file-based
service, the XML parser 1150 outputs the corresponding data
to the EDT handler 1151. On the other hand, if the analyzed
data correspond to data designated to a service guide, the
XML parser 1150 outputs the corresponding data to the SG
handler 1165. The EDT handler 1151 analyzes and processes a
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file description table of a FLUTE protocol, which is
transmitted in an XML structure through the ALC/LCT session.
[00585]
The SG handler 1165 collects and analyzes the data
designated for a service guide, the data being transmitted in
an XML structure, thereby outputting the analyzed data to the
service manager 1122.
[00586]
The file decoder 1162 decodes the data having a
file structure and being transmitted through the ALC/LCT
session, thereby outputting the decoded data to the
middleware engine 1164 or storing the decoded data in a third
storage unit 1163.
Herein, the middleware engine 1164
translates the file structure data (i.e., the application)
and executes the translated application.
Thereafter, the
application may be outputted to an output device, such as a
display screen or speakers, through the application
presentation manager 1170. According to an embodiment of the
present invention, the middleware engine 1164 corresponds to
a JAVA-based middleware engine.
[00587]
Based upon a user-input, the EPG manager 1171
receives EPG data either through the service manager 1122 or
through the SG handler 1165, so as to convert the received
EPG data to a display format, thereby outputting the
converted data to the presentation manager 1170.
[00588]
The application manager 1172 performs overall
management associated with the processing of application data,
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which are being transmitted in object formats, file formats,
and so on.
Furthermore, based upon a user-command inputted
through the UI manager 1173, the controller 1100 controls at
least one of the service manager 1122, the EPG manager 1171,
the application manager 1172, and the presentation manager
1170, so as to enable the user-requested function to be
executed.
The UI manager 1173 transfers the user-input to
the controller 1100 through the UI.
[00589]
Finally, the presentation manager 1170 provides at
least one of the audio and video data being outputted from
the A/V decoder 1161 and the EPG data being outputted from
the EPG manager 1171 to the user through the speaker and/or
display screen.
Basebnad Operation Controller
[00590]
The baseband operation controller 1119 receives the
known data position information and the transmission
parameter information and then forwards M/H frame time
information, a presence or non-presence of a data group of a
selected parade, position information of known data within
the data group, power control information and the like to
each block of the demodulating unit. The baseband operation
controller 1119, as shown in FIG. 47, controls operations of
the demodulator 1112, the channel equalizer 1113, the block
decoder 1115 and the RS frame decoder 1116. And, the baseband
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operation controller 1119 is able to overall operations of
the baseband processor 1110. Moreover, the baseband operation
controller 1119 can be implemented with the separate block or
can be included within a prescribed one of the blocks of the
demodulating unit shown in FIG. 47.
[00591] FIG. 48 is an overall block diagram of the baseband
operation controller 1119.
[00592] Referring to FIG. 48, the baseband operation
controller 1119 can include a parade ID checker 3101, a frame
synchronizer 3102, a parade mapper 3103, a group controller
3104 and a known sequence indication controller 3105.
[00593] The baseband operation controller 1119 receives
known data position information from the known sequence
detector 1114 and receives transmission parameter information
from the signaling decoder 1118. The baseband operation
controller 1119 then generates a control signal necessary for
a baseband processor 1110 of a receiving system. For instance,
the known data position information detected by the known
sequence detector 1114 is inputted to the known sequence
indication controller 3105. And, the transmission parameter
information (i.e., TPC data) decoded by the signaling decoder
1118 is inputted to the parade ID checker 3101.
[00594] The parade ID checker 3101 compares a parade ID
(parade ID selected by a user) contained in the user control
signal to a parade ID inputted from the signaling decoder
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1118. If the two parade IDs are not identical to each other,
the parade ID checker stands by until a next transmission
parameter is inputted from the signaling decoder 1118.
[00595] If
the two parade IDs are identical to each other,
the parade ID checker 3101 outputs the transmission parameter
information to the blocks within the baseband operation
controller 1119 and the overall system.
[00596] If
it is checked that the parade ID in the
transmission parameter information inputted to the parade ID
checker 3101 is identical to the parade ID selected by a user,
the parade ID checker 3101 outputs starting_group_number
(SGN) and number _ of _groups (NOG) to the parade mapper 3103,
outputs sub frame number, slot number
and
parade_repetition cycle PRO) to the frame synchronizer 3102,
outputs SCCC block mode, SCCC out
code mode A,
SCCC outer code mode B, SCCC outer code mode C
and
SCCC outer code mode D to the block decoder 1115, and outputs
RS frame mode, RS code mode
primary and
Rs code mode secondary to the RS frame decoders 1116 and 1117,
respectively.
[00597]
The parade mapper 3103 receives the SGN and the NOG
from the parade ID checker as inputs, decides a data group is
carried by which one of sixteen slots within a Sub-frame, and
then outputs the corresponding information. Data group number
transmitted every sub-frame is set to an integer consecutive
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=
between SGN and (SGN+NOG-1). For instance, if SGN = 3 and NOG
= 4, four groups, of which group numbers are 3, 4, 5 and 6,
are transmitted for the corresponding sub-frames,
respectively. The parade mapper finds a slot number j for
transmitting a data group according to Equation 1 with a
group number i obtained from SGN and NOG.
[00598] In the above example, in case of SGN = 3 and NOG =
4, if they are inserted in Equation 1, slot numbers of groups
transmitted according to the above formula sequentially
become 12, 2, 6 and 10.
[00599] The parade mapper 3103 then outputs the found slot
number information. The slot number information may be
outputted to the signaling decoder 1118. In this case, the
signaling decoder 1118 may identify a start of a subframe or
a end of the subframe by using the slot number information.
[00600] For example of outputting slot numbers, a method of
using a bit vector having 16 bits is available.
[00601] A bit vector SNi (i = 0-15) can be set to 1 if
there exists a group transmitted for an ith slot. A bit vector
SNi (i = 0-15) can be set to 0 if a group transmitted for an
ith slot does not exist. And, this bit vector can be outputted
as slot number information.
[00602] The frame synchronizer 3102 receives the
sub frame number, slot-number and PRC from the parade ID
checker and then sends slot counter and frame mask signals as
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outputs. The slot counter is the signal indicating a
slot _number at a current timing point at which a receiver is
operating. And, the frame mask is the signal indicating
whether a corresponding parade is transmitted for a current
frame. The frame synchronizer 3102 performs a process for
initializing slot counter, sub frame number and frame counter
_ _ frame_
counter
receiving signaling information initially. A counter value
of a current timing point is generated from adding a delayed
slot number L according to a time taken to decode signaling
from demodulation together with the signaling information
inputted in this process. After completion of the
initialization process, slot counter is updated every single
slot period, updates sub_frame counter every period of the
slot counter value, and updates frame _counter every period of
the sub
frame _counter. By referring to the frame counter
information and the PRC information, a frame mask signal is
generated. For example, if a corresponding parade is being
transmitted for a current frame, '1' is outputted as the
frame mask. Otherwise, it is able to output '0'.
[00603] The
group controller 3104 receives the slot number
information from the parade mapper 3103. The group controller
3104 receives the slot counter and frame mask information
from the frame synchronizer 3102. The group controller 3104
then outputs group_presence_indicator indicating whether an
M/H group is being transmitted. For instance, if the slot
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number information inputted from the parade mapper 3103
corresponds to 12, 2, 6 and 10, when the frame mask
information inputted from the frame synchronizer 3102 is 1
and the slot counter inputted from the frame synchronizer
3102 includes 2, 6, 10 and 12, '1' is outputted as the
group presence indicator. Otherwise, it is able to output 0.
[00604]
The group_presence_indicator may be outputted to
the signaling decoder 1118. In this case, the signaling
decoder 1118 may use the group presence indicator to identify
whether a data group exits.
[00605]
The known sequence indication controller 3105
outputs position information of another known data, group
start position information and the like with position
information of specific inputted known data. In this case,
since the known data are present at a previously appointed
position within the data group, if position data of one of a
plurality of known data sequences, it is able to know data
position information of another known sequence, data group
start position information and the like. The known sequence
indication controller 3105 can output known data and data
group position information necessary for the demodulating
unit of the receiving system using
the
group presence_indicator information only if the data group
is transmitted. Alternatively, the known sequence detector
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1114 can perform operations of the known sequence indication
controller 3105.
Channel equalizer
[00606]
The data demodulated by the demodulator 1112 by
using the known data are inputted to the equalizer 1113.
Additionally, the demodulated data may also be inputted to
the known sequence detector 1114. At this point, a data
group that is inputted for the equalization process may be
divided into region A to region D, as shown in FIG. 5. More
specifically, according to the embodiment of the present
invention, region A includes M/H block B4 to M/H block B7,
region B includes M/H block B3 and M/H block B8, region C
includes M/H block B2 and M/H block B9, and region D includes
M/H block Bl and M/H block B10.
In other words, one data
group is divided into M/H blocks from Bl to B10, each M/H
block having the length of 16 segments.
Also, a long
training sequence (i.e., known data sequence) is inserted at
the starting portion of the M/H blocks B4 to B8. Furthermore,
two data groups may be allocated (or assigned) to one VSB
field.
In this case, field synchronization data are
positioned in the 37th segment of one of the two data groups.
[00607]
The present invention may use known data, which
have position and content information based upon an agreement
between the transmitting system and the receiving system,
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and/or field synchronization data for the channel
equalization process.
[00608] The channel equalizer 1113 may perform channel
equalization using a plurality of methods. According to the
present invention, the channel equalizer 1113 uses known data
and/or field synchronization data, so as to estimate a
channel impulse response (CIR), thereby performing channel
equalization.
[00609] Most particularly, an example of estimating the CIR
in accordance with each region within the data group, which
is hierarchically divided and transmitted from the
transmitting system, and applying each CIR differently will
also be described herein.
[00610] At this point, a data group can be assigned and
transmitted a maximum the number of 4 in a VSB frame in the
transmitting system. In this case, all data group do not
include field synchronization data. In the present invention,
the data group including the field synchronization data
performs channel-equalization using the field synchronization
data and known data. And the data group not including the
field synchronization data performs channel-equalization
using the known data.
[00611] For example, the data of the M/H block B3 including
the field synchronization data performs channel-equalization
using the CIR calculated from the field synchronization data
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area and the CIR calculated from the first known data area.
Also, the data of the M/H blocks Bl and 52 performs channel-
equalization using the CIR calculated from the field
synchronization data area and the CIR calculated from the
first known data area. Meanwhile, the data of the M/H blocks
Bl to B3 not including the field synchronization data
performs channel-equalization using CIRS calculated from the
first known data area and the third known data area.
[00612] As described above, the present invention uses the
CIR estimated from the known data region in order to perform
channel equalization on data within the data group. At this
point, each of the estimated CIRs may be directly used in
accordance with the characteristics of each region within the
data group. Alternatively, a plurality of the estimated CIRs
may also be either interpolated or extrapolated so as to
create a new CIR, which is then used for the channel
equalization process.
[00613] Herein, when a value F(Q) of a function F(x) at a
particular point Q and a value F(S) of the function F(x) at
another particular point S are known, interpolation refers to
estimating a function value of a point within the section
between points Q and S. Linear interpolation corresponds to
the simplest form among a wide range of interpolation
operations.
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[00614]
FIG. 49 illustrates an example of linear
interpolation. More specifically, in a random function F(x),
when given the values F(Q) and F(S) each from points x=Q and
x=S, respectively, the approximate value P(P) of the F(x)
function at point x=P may be estimated by using Equation 7
below.
In other words, since the values of F(Q) and F(S)
respective to each point x=Q and x=S are known (or given), a
straight line passing through the two points may be
calculated so as to obtain the approximate value P(P) of the
corresponding function value at point P. At this point, the
straight line passing through points (Q,F(Q)) and (S,F(S))
may be obtained by using Equation 8 below.
Equation 8
P(x) F(S)-F(Q)(x Q)+F(Q)
=
S-Q
[00615]
Accordingly, Equation 9 below shows the process of
substituting p for x in Equation 8, so as to calculate the
approximate value F(P) of the function value at point P.
Equation 9
F(P) = F(S)- F(Q) (P Q)+ F(Q)
S - Q
S
F(P)=- P F(Q)+P-Q F(S)
S -
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CA 02888511 2015-04-20
[00616]
The linear interpolation method of Equation 9 is
merely the simplest example of many other linear
interpolation methods.
Therefore, since any other linear
interpolation method may be used, the present invention will
not be limited only to the examples given herein.
[00617]
Alternatively, when a value F(Q) of a function F(x)
at a particular point Q and a value F(S) of the function F(x)
at another particular point S are known (or given),
extrapolation refers to estimating a function value of a
point outside of the section between points Q and S. Herein,
the simplest form of extrapolation corresponds to linear
extrapolation.
[00618]
FIG. 50 illustrates an example of linear
extrapolation. As described above, for linear extrapolation
as well as linear interpolation, in a random function F(x),
when given the values F(Q) and F(S) each from points x=Q and
x=S, respectively, the approximate value P(P) of the
corresponding function value at point P may be obtained by
calculating a straight line passing through the two points.
Herein, linear extrapolation is the simplest form among a
wide range of extrapolation operations.
Similarly, the
linear extrapolation described herein is merely exemplary
among a wide range of possible extrapolation methods. And,
therefore, the present invention is not limited only to the
examples set forth herein.
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[00619] FIG. 51 illustrates a block diagram of a channel
equalizer according to an embodiment of the present invention.
Referring to FIG. 51, the channel equalizer includes a first
frequency domain converter 4100, a channel estimator 4110, a
second frequency domain converter 4121, a coefficient
calculator 4122, a distortion compensator 4130, and a time
domain converter 4140. Herein, the channel equalizer may
further include a remaining carrier phase error remover, a
noise canceller (NC), and a decision unit.
[00620] The first frequency domain converter 4100 includes
an overlap unit 4101 overlapping inputted data, and a fast
fourier transform (FFT) unit 4102 converting the data
outputted from the overlap unit 4101 to frequency domain data.
[00621] The channel estimator 4110 includes a CIR estimator
4111, a first cleaner 4113, a CIR calculator 4114, a second
cleaner, and a zero-padding unit. herein, the channel
estimator 4110 may further include a phase compensator
compensating a phase of the CIR which estimated in the CIR
estimator 4111.
[00622] The second frequency domain converter 4121 includes
a fast fourier transform (FFT) unit converting the CIR being
outputted from the channel estimator 4110 to frequency domain
CIR.
[00623] The time domain converter 4140 includes an IFFT
unit 4141 converting the data having the distortion
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compensated by the distortion compensator 4130 to time domain
data, and a save unit 4142 extracting only valid data from
the data outputted from the IFFT unit 4141. The output data
from the save unit 4142 corresponds to the channel-equalized
data.
[00624]
If the remaining carrier phase error remover is
connected to an output terminal of the time domain converter
4140, the remaining carrier phase error remover estimates the
remaining carrier phase error included in the channel-
equalized data, thereby removing the estimated error. If the
noise remover is connected to an output terminal of the time
domain converter 4140, the noise remover estimates noise
included in the channel-equalized data, thereby removing the
estimated noise.
[00625]
More specifically, the receiving data demodulated
in FIG. 51 are overlapped by the overlap unit 4101 of the
first frequency domain converter 4100 at a pre-determined
overlapping ratio, which are then outputted to the FFT unit
4102. The FFT unit 4102 converts the overlapped time domain
data to overlapped frequency domain data through by
processing the data with FFT.
Then, the converted data are
outputted to the distortion compensator 4130.
[00626]
The distortion compensator 4130 performs a complex
number multiplication on the overlapped frequency domain data
outputted from the FFT unit 4102 included in the first
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. =
,
frequency domain converter 4100 and the equalization
coefficient calculated from the coefficient calculator 4122,
thereby compensating the channel distortion of the overlapped
data outputted from the FFT unit 4102.
Thereafter, the
compensated data are outputted to the IFFT unit 4141 of the
time domain converter 4140. The IFFT unit 4141 performs IFFT
on the overlapped data having the channel distortion
compensated, thereby converting the overlapped data to time
domain data, which are then outputted to the save unit 4142.
The save unit 4142 extracts valid data from the data of the
channel-equalized and overlapped in the time domain, and
outputs the extracted valid data.
[00627]
Meanwhile, the received data are inputted to the
overlap unit 4101 of the first frequency domain converter
4100 included in the channel equalizer and, at the same time,
inputted to the CIR estimator 4111 of the channel estimator
4110.
[00628]
The CIR estimator 4111 uses a training sequence,
for example, data being inputted during the known data
section and the known data in order to estimate the CIR. If
the data to be channel-equalizing is the data within the data
group including field synchronization data, the training
sequence using in the CIR estimator 4111 may become the field
synchronization data and known data. Meanwhile, if the data
to be channel-equalizing is the data within the data group
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not including field synchronization data, the training
sequence using in the CIR estimator 4111 may become only the
known data.
[00629]
For example, the CIR estimator 4111 estimates CIR
using the known data correspond to reference known data
generated during the known data section by the receiving
system in accordance with an agreement between the receiving
system and the transmitting system.
For this, the CIR
estimator 4111 is provided known data position information
from the known sequence detector 1114. Also the CIR estimator
4111 may be provided field synchronization position
information from the known sequence detector 1114.
[00630]
The estimated CIR passes through the first cleaner
(or pre-CIR cleaner) 4113 or bypasses the first cleaner 4113,
thereby being inputted to the CIR calculator (or CIR
interpolator-extrapolator) 4114.
The CIR calculator 4114
either interpolates or extrapolates an estimated CIR, which
is then outputted to the second cleaner (or post-CIR cleaner)
4115.
[00631]
The first cleaner 4113 may or may not operate
depending upon whether the CIR calculator 4114 interpolates
or extrapolates the estimated CIR.
For example, if the CIR
calculator 4114 interpolates the estimated CIR, the first
cleaner 4113 does not operate.
Conversely, if the CIR
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CA 02888511 2015-04-20
calculator 4114 extrapolates the estimated CIR, the first
cleaner 4113 operates.
[00632]
More specifically, the CIR estimated from the known
data includes a channel element that is to be obtained as
well as a jitter element caused by noise. Since such jitter
element deteriorates the performance of the equalizer, it
preferable that a coefficient calculator 4122 removes the
jitter element before using the estimated CIR.
Therefore,
according to the embodiment of the present invention, each of
the first and second cleaners 4113 and 4115 removes a portion
of the estimated CIR having a power level lower than the
predetermined threshold value (i.e., so that the estimated
CIR becomes equal to '0'). Herein, this removal process will
be referred to as a "CIR cleaning" process.
[00633]
The CIR calculator 4114 performs CIR interpolation
by multiplying CIRs estimated from the CIR estimator 4111 by
each of coefficients, thereby adding the multiplied values.
At this point, some of the noise elements of the CIR may be
added to one another, thereby being cancelled.
Therefore,
when the CIR calculator 4114 performs CIR interpolation, the
original (or initial) CIR having noise elements remaining
therein.
In other words, when the CIR calculator 4114
performs CIR interpolation, the estimated CIR bypasses the
first cleaner 4113 and is inputted to the CIR calculator 4114.
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Subsequently, the second cleaner 4115 cleans the CIR
interpolated by the CIR interpolator-extrapolator 4114.
[00634]
Conversely, the CIR calculator 4114 performs CIR
extrapolation by using a difference value between two CIRs,
so as to estimate a CIR positioned outside of the two CIRs.
Therefore, in this case, the noise element is rather
amplified.
Accordingly, when the CIR calculator 4114
performs CIR extrapolation, the CIR cleaned by the first
cleaner 4113 is used.
More specifically, when the CIR
calculator 4114 performs CIR extrapolation, the extrapolated
CIR passes through the second cleaner 4115, thereby being
inputted to the zero-padding unit 4116.
[00635]
Meanwhile, when a second frequency domain converter
(or fast fourier transform (FFT2)) 4121 converts the CIR,
which has been cleaned and outputted from the second cleaner
4115, to a frequency domain, the length and of the inputted
CIR and the SET size may not match (or be identical to one
another). In other words, the CIR length may be smaller than
the SET size.
In this case, the zero-padding unit 4116 adds
a number of zeros 'O's corresponding to the difference
between the PET size and the CIR length to the inputted CIR,
thereby outputting the processed CIR to the second frequency
domain converter (FFT2) 4121.
Herein, the zero-padded CIR
may correspond to one of the interpolated CIR, extrapolated
CIR, and the CIR estimated in the known data section.
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CA 02888511 2015-04-20
[00636]
The second frequency domain converter 4121 performs
FFT on the CIR being outputted from the zero padding unit
4116, thereby converting the CIR to a frequency domain CIR.
Then, the second frequency domain converter 4121 outputs the
converted CIR to the coefficient calculator 4122.
[00637]
The coefficient calculator 4122 uses the frequency
domain CIR being outputted from the second frequency domain
converter 4121 to calculate the equalization coefficient.
Then, the coefficient calculator 4122 outputs the calculated
coefficient to the distortion compensator 4130.
Herein, for
example, the coefficient calculator 4122 calculates a channel
equalization coefficient of the frequency domain that can
provide minimum mean square error (MMSE) from the CIR of the
frequency domain, which is outputted to the distortion
compensator 4130.
[00638]
The distortion compensator 4130 performs a complex
number multiplication on the overlapped data of the frequency
domain being outputted from the FFT unit 4102 of the first
frequency domain converter 4100 and the equalization
coefficient calculated by the coefficient calculator 4122,
thereby compensating the channel distortion of the overlapped
data being outputted from the FFT unit 4102.
Block decoder
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CA 02888511 2015-04-20
[00639] Meanwhile, if the data being inputted to the block
decoder 1115, after being channel-equalized by the equalizer
1113, correspond to the data having both block encoding and
trellis encoding performed thereon (i.e., the data within the
RS frame, the signaling information data, etc.) by the
transmitting system, trellis decoding and block decoding
processes are performed on the inputted data as inverse
processes of the transmitting system. Alternatively, if the
data being inputted to the block decoder 1115 correspond to
the data having only trellis encoding performed thereon (i.e.,
the main service data), and not the block encoding, only the
trellis decoding process is performed on the inputted data as
the inverse process of the transmitting system.
[00640] The trellis decoded and block decoded data by the
block decoder 1115 are then outputted to the RS frame decoder
1116. More specifically, the block decoder 1115 removes the
known data, data used for trellis initialization, and
signaling information data, MPEG header, which have been
inserted in the data group, and the RS parity data, which
have been added by the RS encoder/non-systematic RS encoder
or non-systematic RS encoder of the transmitting system.
Then, the block decoder 1115 outputs the processed data to
the RS frame decoder 1116. Herein, the removal of the data
may be performed before the block decoding process, or may be
performed during or after the block decoding process.
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[00641]
Meanwhile, the data trellis-decoded by the block
decoder 1115 are outputted to the data deinterleaver of the
main service data processor (not shown). At this point, the
data being trellis-decoded by the block decoder 1115 and
outputted to the data deinterleaver may not only include the
main service data but may also include the data within the RS
frame and the signaling information.
Furthermore, the RS
parity data that are added by the transmitting system after
the pre-processor 230 may also be included in the data being
outputted to the data deinterleaver.
[00642]
According to another embodiment of the present
invention, data that are not processed with block decoding
and only processed with trellis encoding by the transmitting
system may directly bypass the block decoder 1115 so as to be
outputted to the data deinterleaver. In this case, a trellis
decoder should be provided before the data deinterleaver.
More specifically, if the inputted data correspond to the
data having only trellis encoding performed thereon and not
block encoding, the block decoder 1115 performs Viterbi (or
trellis) decoding on the inputted data so as to output a hard
decision value or to perform a hard-decision on a soft
decision value, thereby outputting the result.
[00643]
Meanwhile, if the inputted data correspond to the
data having both block encoding process and trellis encoding
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process performed thereon, the block decoder 1115 outputs a
soft decision value with respect to the inputted data.
[00644]
In other words, if the inputted data correspond to
data being processed with block encoding by the block
processor 302 and being processed with trellis encoding by
the trellis encoding module 256, in the transmitting system,
the block decoder 1115 performs a decoding process and a
trellis decoding process on the inputted data as inverse
processes of the transmitting system. At this point, the RS
frame encoder of the pre-processor included in the
transmitting system may be viewed as an outer (or external)
encoder. And, the trellis encoder may be viewed as an inner
(or internal) encoder. When decoding such concatenated codes,
in order to allow the block decoder 1115 to maximize its
performance of decoding externally encoded data, the decoder
of the internal code should output a soft decision value.
[00645]
FIG. 52 illustrates a detailed block diagram of the
block decoder 1115 according to an embodiment of the present
invention.
Referring to FIG. 52, the block decoder 1115
includes a feedback controller 5010, an input buffer 5011, a
trellis decoding unit (or 12-way trellis coded modulation
(TCM) decoder or inner decoder) 5012, a symbol-byte converter
5013, an outer block extractor 5014, a feedback deformatter
5015, a symbol deinterleaver 5016, an outer symbol mapper
5017, a symbol decoder 5018, an inner symbol mapper 5019, a
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symbol interleaver 5020, a feedback formatter 5021, and an
output buffer 5022.
Herein, just as in the transmitting
system, the trellis decoding unit 5012 may be viewed as an
inner (or internal) decoder. And, the symbol decoder 5018
may be viewed as an outer (or external) decoder.
[00646]
The input buffer 5011 temporarily stores the mobile
service data symbols being channel-equalized and outputted
from the equalizer 1113. (Herein, the mobile service data
symbols may include symbols corresponding to the signaling
information, RS parity data symbols and CRC data symbols
added during the encoding process of the RS frame.)
Thereafter, the input buffer 5011 repeatedly outputs the
stored symbols for M number of times to the trellis decoding
unit 5012 in a turbo block (TDL) size required for the turbo
decoding process.
[00647]
The turbo decoding length (TDL) may also be
referred to as a turbo block.
Herein, a TDL should include
at least one SCCC block size. Therefore, as defined in FIG.
5, when it is assumed that one M/H block is a 16-segment unit,
and that a combination of 10 M/H blocks form one SCCC block,
a TDL should be equal to or larger than the maximum possible
combination size. For example, when it is assumed that 2 M/H
blocks form one SCCC block, the TDL may be equal to or larger
than 32 segments (i.e., 828x32=26496 symbols).
Herein, M
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indicates a number of repetitions for turbo-decoding pre-
decided by the feed-back controller 5010.
[00648]
Also, M represents a number of repetitions of the
turbo decoding process, the number being predetermined by the
feedback controller 5010.
[00649]
Additionally, among the values of symbols being
channel-equalized and outputted from the equalizer 1113, the
input symbol values corresponding to a section having no
mobile service data symbols (including RS parity data symbols
during RS frame encoding and CRC data symbols) included
therein, bypass the input buffer 5011 without being stored.
More specifically, since trellis-encoding is performed on
input symbol values of a section wherein SCCC block-encoding
has not been performed, the input buffer 5011 inputs the
inputted symbol values of the corresponding section directly
to the trellis encoding module 5012 without performing any
storage, repetition, and output processes.
The storage,
repetition, and output processes of the input buffer 5011 are
controlled by the feedback controller 5010.
Herein, the
feedback controller 5010 refers to SCCC-associated
information (e.g., SCCC block mode and SCCC outer code mode),
which are outputted from the signaling decoder 1118 or the
baseband operation controller 1119, in order to control the
storage and output processes of the input buffer 5011.
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[00650]
The trellis decoding unit 5012 includes a 12-way
TCM decoder. Herein, the trellis decoding unit 5012 performs
12-way trellis decoding as inverse processes of the 12-way
trellis encoder.
[00651]
More specifically, the trellis decoding unit 5012
receives a number of output symbols of the input buffer 5011
and soft-decision values of the feedback formatter 5021
equivalent to each TDL, so as to perform the TCM decoding
process.
[00652]
At this point, based upon the control of the
feedback controller 5010, the soft-decision values outputted
from the feedback formatter 5021 are matched with a number of
mobile service data symbol places so as to be in a one-to-one
(1:1) correspondence.
Herein, the number of mobile service
data symbol places is equivalent to the TDL being outputted
from the input buffer 5011.
[00653]
More specifically, the mobile service data being
outputted from the input buffer 5011 are matched with the
turbo decoded data being inputted, so that each respective
data place can correspond with one another. Thereafter, the
matched data are outputted to the trellis decoding unit 5012.
For example, if the turbo decoded data correspond to the
third symbol within the turbo block, the corresponding symbol
(or data) is matched with the third symbol included in the
turbo block, which is outputted from the input buffer 5011.
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Subsequently, the matched symbol (or data) is outputted to
the trellis decoding unit 5012.
[00654]
In order to do so, while the regressive turbo
decoding is in process, the feedback controller 5010 controls
the input buffer 5011 so that the input buffer 5011 stores
the corresponding turbo block data. Also, by delaying data
(or symbols), the soft decision value (e.g., LLR) of the
symbol outputted from the symbol interleaver 5020 and the
symbol of the input buffer 5011 corresponding to the same
place (or position) within the block of the output symbol are
matched with one another to be in a one-to-one correspondence.
Thereafter, the matched symbols are controlled so that they
can be inputted to the TCM decoder through the respective
path. This process is repeated for a predetermined number of
turbo decoding cycle periods.
Then, the data of the next
turbo block are outputted from the input buffer 5011, thereby
repeating the turbo decoding process.
[00655]
The output of the trellis decoding unit 5012
signifies a degree of reliability of the transmission bits
configuring each symbol.
For example, in the transmitting
system, since the input data of the trellis encoding module
correspond to two bits as one symbol, a log likelihood ratio
(LLR) between the likelihood of a bit having the value of '1'
and the likelihood of the bit having the value of '0' may be
respectively outputted (in bit units) to the upper bit and
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.*
the lower bit. Herein, the log likelihood ratio corresponds
to a log value for the ratio between the likelihood of a bit
having the value of '1' and the likelihood of the bit having
the value of '0'. Alternatively, a LLR for the likelihood of
2 bits (i.e., one symbol) being equal to "00", "01", "10",
and "11" may be respectively outputted (in symbol units) to
all 4 combinations of bits (i.e., 00, 01, 10, 11).
Consequently, this becomes the soft decision value that
indicates the degree of reliability of the transmission bits
configuring each symbol. A maximum a posteriori probability
(MAP) or a soft-out Viterbi algorithm (SOVA) may be used as a
decoding algorithm of each TCM decoder within the trellis
decoding unit 5012.
[00656]
The output of the trellis decoding unit 5012 is
inputted to the symbol-byte converter 5013 and the outer
block extractor 5014.
[00657]
The symbol-byte converter 5013 performs a hard-
decision process of the soft decision value that is trellis
decoded and outputted from the trellis decoding unit 5012.
Thereafter, the symbol-byte converter 5013 groups 4 symbols
into byte units, which are then outputted to the data
deinterleaver of the main service data processor.
More
specifically, the symbol-byte converter 5013 performs hard-
decision in bit units on the soft decision value of the
symbol outputted from the trellis decoding unit 5012.
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Therefore, the data processed with hard-decision and
outputted in bit units from the symbol-byte converter 5013
not only include main service data, but may also include
mobile service data, known data, RS parity data, and MPEG
headers.
[00658]
Among the soft decision values of TDL size of the
trellis decoding unit 5012, the outer block extractor 5014
identifies the soft decision values of B size of
corresponding to the mobile service data symbols (wherein
symbols corresponding to signaling information, RS parity
data symbols that are added during the encoding of the RS
frame, and CRC data symbols are included) and outputs the
identified soft decision values to the feedback deformatter
5015.
[00659]
The feedback deformatter 5015 changes the
processing order of the soft decision values corresponding to
the mobile service data symbols. This is an inverse process
of an initial change in the processing order of the mobile
service data symbols, which are generated during an
intermediate step, wherein the output symbols outputted from
the block processor 302 of the transmitting system are being
inputted to the trellis encoding module 256 (e.g., when the
symbols pass through the group formatter, the data
deinterleaver, the packet formatter, and the data
interleaver).
Thereafter, the feedback deformatter 5015
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. .
performs reordering of the process order of soft decision
values corresponding to the mobile service data symbols and,
then, outputs the processed mobile service data symbols to
the symbol deinterleaver 5016.
[00660]
This is because a plurality of blocks exist between
the block processor 302 and the trellis encoding module 256,
and because, due to these blocks, the order of the mobile
service data symbols being outputted from the block processor
302 and the order of the mobile service data symbols being
inputted to the trellis encoding module 256 are not identical
to one another.
Therefore, the feedback deformatter 5015
reorders (or rearranges) the order of the mobile service data
symbols being outputted from the outer block extractor 5014,
so that the order of the mobile service data symbols being
inputted to the symbol deinterleaver 5016 matches the order
of the mobile service data symbols outputted from the block
processor 302 of the transmitting system.
The reordering
process may be embodied as one of software, middleware, and
hardware.
[00661] The symbol deinterleaver 5016
performs
deinterleaving on the mobile service data symbols having
their processing orders changed and outputted from the
feedback deformatter 5015, as an inverse process of the
symbol interleaving process of the symbol interleaver 514
included in the transmitting system.
The size of the block
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=
used by the symbol deinterleaver 5016 during the
deinterleaving process is identical to interleaving size of
an actual symbol (i.e., B) of the symbol interleaver 514,
which is included in the transmitting system.
This is
because the turbo decoding process is performed between the
trellis decoding unit 5012 and the symbol decoder 5018. Both
the input and output of the symbol deinterleaver 5016
correspond to soft decision values, and the deinterleaved
soft decision values are outputted to the outer symbol mapper
5017.
[00662]
The operations of the outer symbol mapper 5017 may
vary depending upon the structure and coding rate of the
convolution encoder 513 included in the transmitting system.
For example, when data are 1/2-rate encoded by the
convolution encoder 513 and then transmitted, the outer
symbol mapper 5017 directly outputs the input data without
modification.
In another example, when data are 1/4-rate
encoded by the convolution encoder 513 and then transmitted,
the outer symbol mapper 5017 converts the input data so that
it can match the input data format of the symbol decoder 5018.
For this, the outer symbol mapper 5017 may be inputted SCCC-
associated information (i.e., SCCC block mode and SCCC outer
code mode) from the signaling decoder 1118. Then, the outer
symbol mapper 5017 outputs the converted data to the symbol
decoder 5018.
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. .
[00663]
The symbol decoder 5018 (i.e., the outer decoder)
receives the data outputted from the outer symbol mapper 5017
and performs symbol decoding as an inverse process of the
convolution encoder 513 included in the transmitting system.
At this point, two different soft decision values are
outputted from the symbol decoder 5018. One of the outputted
soft decision values corresponds to a soft decision value
matching the output symbol of the convolution encoder 513
(hereinafter referred to as a "first decision value").
The
other one of the outputted soft decision values corresponds
to a soft decision value matching the input bit of the
convolution encoder 513 (hereinafter referred to as a "second
decision value").
[00664]
More specifically, the first decision value
represents a degree of reliability the output symbol (i.e., 2
bits) of the convolution encoder 513. Herein, the first soft
decision value may output (in bit units) a LLR between the
likelihood of 1 bit being equal to '1' and the likelihood of
1 bit being equal to '0' with respect to each of the upper
bit and lower bit, which configures a symbol. Alternatively,
the first soft decision value may also output (in symbol
units) a LLR for the likelihood of 2 bits being equal to "00",
"01", "10", and "11" with respect to all possible
combinations.
The first soft decision value is fed-back to
the trellis decoding unit 5012 through the inner symbol
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mapper 5019, the symbol interleaver 5020, and the feedback
formatter 5021. On the other hand, the second soft decision
value indicates a degree of reliability the input bit of the
convolution encoder 513 included in the transmitting system.
Herein, the second soft decision value is represented as the
LLR between the likelihood of 1 bit being equal to '1' and
the likelihood of 1 bit being equal to '0'. Thereafter, the
second soft decision value is outputted to the outer buffer
5022. In this case, a maximum a posteriori probability (MAP)
or a soft-out Viterbi algorithm (SOVA) may be used as the
decoding algorithm of the symbol decoder 5018.
[00665]
The first soft decision value that is outputted
from the symbol decoder 5018 is inputted to the inner symbol
mapper 5019. The inner symbol mapper 5019 converts the first
soft decision value to a data format corresponding the input
data of the trellis decoding unit 5012.
Thereafter, the
inner symbol mapper 5019 outputs the converted soft decision
value to the symbol interleaver 5020. The operations of the
inner symbol mapper 5019 may also vary depending upon the
structure and coding rate of the convolution encoder 513
included in the transmitting system.
[00666]
The symbol interleaver 5020 performs symbol
interleaving, as shown in FIG. 30, on the first soft decision
value that is outputted from the inner symbol mapper 5019.
Then, the symbol interleaver 5020 outputs the symbol-
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interleaved first soft decision value to the feedback
formatter 5021. Herein, the output of the symbol interleaver
5020 also corresponds to a soft decision value.
[00667]
With respect to the changed processing order of the
soft decision values corresponding to the symbols that are
generated during an intermediate step, wherein the output
symbols outputted from the block processor 302 of the
transmitting system are being inputted to the trellis
encoding module (e.g., when the symbols pass through the
group formatter, the data deinterleaver, the packet formatter,
the RS encoder, and the data interleaver), the feedback
formatter 5021 alters (or changes) the order of the output
values outputted from the symbol interleaver 5020.
Subsequently, the feedback formatter 5020 outputs values to
the trellis decoding unit 5012 in the changed order. The
reordering process of the feedback formatter 5021 may
configure at least one of software, hardware, and middleware.
[00668]
The soft decision values outputted from the symbol
interleaver 5020 are matched with the positions of mobile
service data symbols each having the size of TDL, which are
outputted from the input buffer 5011, so as to be in a one-
to-one correspondence. Thereafter, the soft decision values
matched with the respective symbol position are inputted to
the trellis decoding unit 5012.
At this point, since the
main service data symbols or the RS parity data symbols and
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known data symbols of the main service data do not correspond
to the mobile service data symbols, the feedback formatter
5021 inserts null data in the corresponding positions,
thereby outputting the processed data to the trellis decoding
unit 5012.
Additionally, each time the symbols having the
size of TDL are turbo decoded, no value is fed-back by the
symbol interleaver 5020 starting from the beginning of the
first decoding process.
Therefore, the feedback formatter
5021 is controlled by the feedback controller 5010, thereby
inserting null data into all symbol positions including a
mobile service data symbol.
Then, the processed data are
outputted to the trellis decoding unit 5012.
[00669]
The output buffer 5022 receives the second soft
decision value from the symbol decoder 5018 based upon the
control of the feedback controller 5010.
Then, the output
buffer 5022 temporarily stores the received second soft
decision value.
Thereafter, the output buffer 5022 outputs
the second soft decision value to the RS frame decoders 1116
and 1117. For example, the output buffer 5022 overwrites the
second soft decision value of the symbol decoder 5018 until
the turbo decoding process is performed for M number of times.
Then, once all M number of turbo decoding processes is
performed for a single TDL, the corresponding second soft
decision value is outputted to the RS frame decoders 1116 and
1117.
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[00670]
The feedback controller 5010 controls the number of
turbo decoding and turbo decoding repetition processes of the
overall block decoder, shown in FIG. 52. More specifically,
once the turbo decoding process has been repeated for a
predetermined number of times, the second soft decision value
of the symbol decoder 5018 is outputted to the RS frame
decoders 1116 and 1117 through the output buffer 5022. Thus,
the block decoding process of a turbo block is completed. In
the description of the present invention, this process is
referred to as a regressive turbo decoding process for
simplicity.
[00671]
At this point, the number of regressive turbo
decoding rounds between the trellis decoding unit 5012 and
the symbol decoder 5018 may be defined while taking into
account hardware complexity and error correction performance.
Accordingly, if the number of rounds increases, the error
correction performance may be enhanced.
However, this may
lead to a disadvantageous of the hardware becoming more
complicated (or complex).
[00672]
Meanwhile, the main service data processor
corresponds to block required for receiving the main service
data.
Therefore, the above-mentioned blocks may not be
necessary (or required) in the structure of a digital
broadcast receiving system for receiving mobile service data
only.
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. .
[00673]
The data deinterleaver of the main service data
processor performs an inverse process of the data interleaver
included in the transmitting system.
In other words, the
data deinterleaver deinterleaves the main service data
outputted from the block decoder 1115 and outputs the
deinterleaved main service data to the RS decoder. The data
being inputted to the data deinterleaver include main service
data, as well as mobile service data, known data, RS parity
data, and an MPEG header. At this point, among the inputted
data, only the main service data and the RS parity data added
to the main service data packet may be outputted to the RS
decoder.
Also, all data outputted after the data
derandomizer may all be removed with the exception for the
main service data.
In the embodiment of the present
invention, only the main service data and the RS parity data
added to the main service data packet are inputted to the RS
decoder.
[00674]
The RS decoder performs a systematic RS decoding
process on the deinterleaved data and outputs the processed
data to the data derandomizer.
[00675]
The data derandomizer receives the output of the RS
decoder and generates a pseudo random data byte identical to
that of the randomizer included in the digital broadcast
transmitting system.
Thereafter, the data derandomizer
performs a bitwise exclusive OR (XOR) operation on the
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. .
generated pseudo random data byte, thereby inserting the MPEG
synchronization bytes to the beginning of each packet so as
to output the data in 188-byte main service data packet units.
RS Frame Decoder
[00676]
The data outputted from the block decoder 1115 are
in portion units.
More specifically, in the transmitting
system, the RS frame is divided into several portions, and
the mobile service data of each portion are assigned either
to regions A/B/C/D within the data group or to any one of
regions A/B and regions C/D , thereby being transmitted to
the receiving system. Therefore, the primary RS frame decoder
1116 gathers (or collects or groups) a plurality of portions
within a single parade so as to configure a single RS frame
(i.e., a primary RS frame), or the primary RS frame decoder
1116 and the secondary RS frame decoder 1117 gather (or
collect or group) a plurality of portions within a single
parade so as to respectively configure a primary RS frame and
a secondary RS frame, thereby performing error correction
decoding in RS frame units.
[00677]
For example, when the RS frame mode value is equal
to '00', then one parade transmits one RS frame.
At this
point, one RS frame is divided into several portions, and the
mobile service data of each portion are assigned to regions
A/B/C/D of the corresponding data group, thereby being
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transmitted. In this case, the primary RS frame decoder 1116
extracts mobile service data from regions A/B/C/D of the
corresponding data group, as shown in FIG. 53(a).
Subsequently, the primary RS frame decoder 1116 may perform
the process of forming (or creating) a portion on a plurality
of data group within a parade, thereby forming several
portions. Then, the several portions of mobile service data
may be grouped to form an RS frame (i.e., primary RS frame).
Herein, if stuffing bytes are added to the last portion, the
RS frame may be formed after removing the stuffing byte.
[00678]
In another example, when the RS frame mode value is
equal to '01', then one parade transmits two RS frames (i.e.,
a primary RS frame and a secondary RS frame). At this point,
a primary RS frame is divided into several primary portions,
and the mobile service data of each primary portion are
assigned to regions A/B of the corresponding data group,
thereby being transmitted.
Also, a secondary RS frame is
divided into several secondary portions, and the mobile
service data of each secondary portion are assigned to
regions C/D of the corresponding data group, thereby being
transmitted.
[00679]
In this case, the primary RS frame decoder 1116
extracts mobile service data from regions A/B of the
corresponding data group, as shown in FIG. 53(b).
Subsequently, the RS frame decoder 1116 may perform the
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=
process of forming (or creating) a primary portion on a
plurality of data group within a parade, thereby forming
several primary portions. Then, the several primary portions
of mobile service data may be grouped to form a primary RS
frame.
Herein, if stuffing bytes are added to the last
primary portion, the primary RS frame may be formed after
removing the stuffing byte.
Also, the secondary RS frame
decoder 1117 extracts mobile service data from regions C/D of
the corresponding data group. Subsequently, the secondary RS
frame decoder 1117 may perform the process of forming (or
creating) a secondary portion on a plurality of data group
within a parade, thereby forming several secondary portions.
Then, the several secondary portions of mobile service data
may be grouped to form a secondary RS frame.
Herein, if
stuffing bytes are added to the last secondary portion, the
secondary RS frame may be formed after removing the stuffing
byte.
[00680]
More specifically, the primary RS frame decoder
1116 and the secondary RS frame decoder 1117 receive the RS-
encoded and/or CRC-encoded mobile service data of each
portion from the block decoder 1115.
Then, the RS frame
decoder 1116 groups several portions, which are inputted
based upon RS frame-associated information outputted from the
signaling decoder 1118 or the baseband operation controller
1119, thereby performing error correction.
By referring to
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the RS frame mode value included in the RS frame-associated
information, the RS frame decoder 1116 may form an RS frame
and may also be informed of the number of RS code parity data
bytes and the code size.
[00681]
The primary RS frame decoder 1116 refers to the
information associated with the RS frame so as to perform an
inverse process of the primary encoder 410 included in the
transmitting system, thereby correcting the errors within the
RS frame.
Subsequently, the primary RS frame decoder 1116
performs derandomizing on the payload of the error-corrected
primary RS frame.
[00682]
The secondary RS frame decoder 1117 refers to the
information associated with the RS frame so as to perform an
inverse process of the secondary encoder 420 included in the
transmitting system, thereby correcting the errors within the
RS frame. Subsequently, the secondary RS frame decoder 1117
performs derandomizing on the payload of the error-corrected
secondary RS frame.
[00683]
FIG. 54 illustrates a process of creating an RS
frame and an RS frame reliability map by grouping (or
collecting) a plurality of portions being transmitted to a
single payload, when the RS frame mode value is equal to '00'.
In this case, only the primary RS frame decoder 1116 is
operated. Therefore, the operations of the primary RS frame
decoder 1116 will be described in detail in a later process.
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If the RS frame mode value is equal to '01', then both the
primary RS frame decoder 1116 and the secondary RS frame
decoder 1117 are operated. And, in this case, the operations
of the primary RS frame decoder 1116 may be directly applied
to the operations of the secondary RS frame decoder 1117.
[00684]
More specifically, the primary RS frame decoder
1116 receives and groups a plurality of mobile service data
bytes, so as to form an RS frame. According to the present
invention, in transmitting system, the mobile service data
correspond to data RS-encoded in RS frame units.
At this
point, the mobile service data may already be error
correction encoded (e.g., CRC-encoded). Alternatively, the
error correction encoding process may be omitted.
[00685]
It is assumed that, in the transmitting system, an
RS frame having the size of (N+2)x(187+P) bytes is divided
into M number of portions, and that the M number of mobile
service data portions are assigned and transmitted to regions
A/B/C/D in M number of data groups, respectively.
In this
case, in the receiving system, each mobile service data
portion is grouped, as shown in FIG. 54(a), thereby forming
an RS frame having the size of (N+2)x(187+P) bytes. At this
point, when stuffing bytes (S) are added to at least one
portion included in the corresponding RS frame and then
transmitted, the stuffing bytes are removed, thereby
configuring an RS frame and an RS frame reliability map. For
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=
example, as shown in FIG. 27, when S number of stuffing bytes
are added to the corresponding portion, the S number of
stuffing bytes are removed, thereby configuring the RS frame
and the RS frame reliability map.
[00686]
Herein, when it is assumed that the block decoder
1115 outputs a soft decision value for the decoding result,
the RS frame decoder 1116 may decide the '0' and '1' of the
corresponding bit by using the codes of the soft decision
value. 8
bits that are each decided as described above are
grouped to create 1 data byte.
If the above-described
process is performed on all soft decision values of several
portions (or data groups) included in a parade, the RS frame
having the size of (N+2)x(187+P) bytes may be configured.
[00687]
Additionally, the present invention uses the soft
decision value not only to configure the RS frame but also to
configure a reliability map.
[00688]
Herein, the reliability map indicates the
reliability of the corresponding data byte, which is
configured by grouping 8 bits, the 8 bits being decided by
the codes of the soft decision value.
[00689]
For example, when the absolute value of the soft
decision value exceeds a pre-determined threshold value, the
value of the corresponding bit, which is decided by the code
of the corresponding soft decision value, is determined to be
reliable.
Conversely, when the absolute value of the soft
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decision value does not exceed the pre-determined threshold
value, the value of the corresponding bit is determined to be
unreliable. Thereafter, if even a single bit among the 8 bits,
which are decided by the codes of the soft decision value and
group to configure one data byte, is determined to be
unreliable, the corresponding data byte is marked on the
reliability map as an unreliable data byte.
[00690]
Herein, determining the reliability of one data byte
is only exemplary. More specifically, when a plurality of data
bytes (e.g., at least 4 data bytes) are determined to be
unreliable, the corresponding data bytes may also be marked as
unreliable data bytes within the reliability map. Conversely,
when all of the data bits within the one data byte are
determined to be reliable (i.e., when the absolute value of the
soft decision values of all 8 bits included in the one data
byte exceed the predetermined threshold value), the
corresponding data byte is marked to be a reliable data byte on
the reliability map. Similarly, when a plurality of data bytes
(e.g., at least 4 data bytes) are determined to be reliable,
the corresponding data bytes may also be marked as reliable
data bytes within the reliability map. The numbers proposed in
the above-described example are merely exemplary and,
therefore, do not limit the scope of the present invention.
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[00691]
The process of configuring the RS frame and the
process of configuring the reliability map both using the
soft decision value may be performed at the same time.
Herein, the reliability information within the reliability
map is in a one-to-one correspondence with each byte within
the RS frame.
For example, if a RS frame has the size of
(N+2)x(187+P) bytes, the reliability map is also configured
to have the size of (N+2)x(187+P) bytes. FIG. 54(a') and FIG.
54(b') respectively illustrate the process steps of
configuring the reliability map according to the present
invention.
[00692]
Subsequently, the RS frame reliability map is used
on the RS frames so as to perform error correction.
[00693]
FIG. 55 illustrates example of the error correction
processed according to embodiments of the present invention.
FIG. 55 illustrates an example of performing an error
correction process when the transmitting system has performed
both RS encoding and CRC encoding processes on the RS frame.
[00694]
As shown in FIG. 55(a) and FIG. 55(a'), when the RS
frame having the size of (N+2)x(187+P) bytes and the RS frame
reliability map having the size of (N+2)x(187+P) bytes are
created, a CRC syndrome checking process is performed on the
created RS frame, thereby verifying whether any error has
occurred in each row. Subsequently, whether or not an error
exists, is indicated (or marked) on a CRC error flag
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corresponding to each row, as shown in (b) of FIG. 55.
At
this point, in the reliability map, since the portion
corresponding to the CRC checksum has no applicability, the
corresponding portion is removed (or deleted), so that only
Nx(187+P) number of reliability information can remain, as
shown in (b') of FIG. 55.
[00695]
After performing the CRC syndrome check, as
described above, (187+P, 187)-RS decoding is performed on N
number of columns. At this point, among the total N+2 number
of columns, with the exception of the last 2 columns, RS-
decoding is performed only on the N number of columns because
each of the last 2 columns is configured only of CRC checksum,
and also because the transmitting end (or transmitting
system) did not perform RS-encoding on the corresponding
columns.
[00696]
Herein, a RS erasure correction process may be
performed in accordance with the number of CRC error flags.
More specifically, as shown in FIG. 55(c), the CRC error flag
corresponding to each row within the RS frame is verified.
Thereafter, the RS frame decoder 1116 determines whether the
number of rows having a CRC error occurring therein is equal
to or smaller than the maximum number of errors on which the
RS erasure correction may be performed, when performing the
RS decoding process in a column direction.
The maximum
number of errors corresponds to P number of parity bytes
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. .
inserted when performing the RS encoding process.
In the
embodiment of the present invention, it is assumed that 48
parity bytes have been added to each column (i.e., P=48).
[00697]
If the number of rows having the CRC errors
occurring therein is smaller than or equal to the maximum
number of errors (i.e., 48 errors according to this
embodiment) that can be corrected by the RS erasure decoding
process, a (235,187)-RS erasure decoding process is performed
in a column direction on the RS frame having (187+P) number
of N-byte rows (i.e., 235 N-byte rows), as shown in FIG.
55(d).
Thereafter, as shown in FIG. 55(e), the 48-byte
parity data that have been added at the end of each column
are removed.
Conversely, however, if the number of rows
having the CRC errors occurring therein is greater than the
maximum number of errors (i.e., 48 errors) that can be
corrected by the RS erasure decoding process, the RS erasure
decoding process cannot be performed.
In this case, the
error may be corrected by performing a general RS decoding
process.
In addition, the reliability map, which has been
created based upon the soft decision value along with the RS
frame, may be used to further enhance the error correction
ability (or performance) of the present invention.
[00698]
More specifically, the RS frame decoder 1116
compares the absolute value of the soft decision value of the
block decoder 1115 with the pre-determined threshold value,
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so as to determine the reliability of the bit value decided
by the code of the corresponding soft decision value. Also,
8 bits, each being determined by the code of the soft
decision value, are grouped to form one data byte.
Accordingly, the reliability information on this one data
byte is indicated on the reliability map.
Therefore, as
shown in FIG. 55(c), even though a particular row is
determined to have an error occurring therein based upon a
CRC syndrome checking process on the particular row, the
present invention does not assume that all bytes included in
the row have errors occurring therein. The present invention
refers to the reliability information of the reliability map
and sets only the bytes that have been determined to be
unreliable as erroneous bytes.
In other words, with
disregard to whether or not a CRC error exists within the
corresponding row, only the bytes that are determined to be
unreliable based upon the reliability map are set as erasure
points.
[00699]
According to another method, when it is determined
that CRC errors are included in the corresponding row, based
upon the result of the CRC syndrome checking result, only the
bytes that are determined by the reliability map to be
unreliable are set as errors.
More specifically, only the
bytes corresponding to the row that is determined to have
errors included therein and being determined to be unreliable
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based upon the reliability information, are set as the
erasure points.
Thereafter, if the number of error points
for each column is smaller than or equal to the maximum
number of errors (i.e., 48 errors) that can be corrected by
the RS erasure decoding process, an RS erasure decoding
process is performed on the corresponding column. Conversely,
if the number of error points for each column is greater than
the maximum number of errors (i.e., 48 errors) that can be
corrected by the RS erasure decoding process, a general
decoding process is performed on the corresponding column.
[00700]
More specifically, if the number of rows having CRC
errors included therein is greater than the maximum number of
errors (i.e., 48 errors) that can be corrected by the RS
erasure decoding process, either an RS erasure decoding
process or a general RS decoding process is performed on a
column that is decided based upon the reliability information
of the reliability map, in accordance with the number of
erasure points within the corresponding column. For example,
it is assumed that the number of rows having CRC errors
included therein within the RS frame is greater than 48. And,
it is also assumed that the number of erasure points decided
based upon the reliability information of the reliability map
is indicated as 40 erasure points in the first column and as
50 erasure points in the second column.
In this case, a
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(235,187)-RS erasure decoding process is performed on the
first column.
[00701]
Alternatively, a (235,187)-RS decoding process is
performed on the second column.
When error correction
decoding is performed on all column directions within the RS
frame by using the above-described process, the 48-byte
parity data which were added at the end of each column are
removed, as shown in FIG. 55(e).
[00702]
As described above, even though the total number of
CRC errors corresponding to each row within the RS frame is
greater than the maximum number of errors that can be
corrected by the RS erasure decoding process, when the number
of bytes determined to have a low reliability level, based
upon the reliability information on the reliability map
within a particular column, while performing error correction
decoding on the particular column.
Herein, the difference
between the general RS decoding process and the RS erasure
decoding process is the number of errors that can be
corrected.
[00703]
More specifically, when performing the general RS
decoding process, the number of errors corresponding to half
of the number of parity bytes (i.e., (number of parity
bytes)/2) that are inserted during the RS encoding process
may be error corrected (e.g., 24 errors may be corrected).
Alternatively, when performing the RS erasure decoding
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process, the number of errors corresponding to the number of
parity bytes that are inserted during the RS encoding process
may be error corrected (e.g., 48 errors may be corrected).
[00704]
After performing the error correction decoding
process, as described above, a RS frame payload configured of
187 N-byte rows (or packet) may be obtained as shown in FIG.
55(e).
Also, derandomizing is performed on a (N+187)-byte
payload of the RS frame as an inverse process of the
transmitting system. Each M/H service data packet (i.e., M/H
TP packet) of the derandomized RS frame payload is outputted
to the TP handler 1133. As described above, each of the M/H
service data packets may consist of a 2-byte M/H header, a k-
byte stuffing region, and a (N-2-k)-byte M/H payload.
At
this point, the value of k may be equal to or greater than
'0'. And, the M/H header includes a type_indicator field, an
error indicator field, a stuff indicator field, and a pointer
field.
[00705]
The present invention may be provided with a number
of RS frame decoders corresponding to a number(=M) of parades
within a single M/H frame. Herein, the M number of RS frame
decoders is provided in parallel.
Each of the M number of
RS frame decoders may be configured by equipping the RS frame
decoder with a multiplexer multiplexing a plurality of
portion at the inputting end, and by equipping the RS frame
decoder with a demultiplexer at the outputting end.
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,
[00706]
FIG. 56 illustrates an error correction decoding
process according to another embodiment of the present
invention.
Herein, FIG. 56 also illustrates an error
correction process according to the other embodiment of the
present invention, when the transmitting system has performed
both RS-encoding and CRC-encoding on the RS frame.
[00707]
According to this embodiment of the present
invention, in case of FIG. 56, a CRC syndrome check is
performed once again on the RS frame already processed with
CRC-RS decoding.
Then, the CRC syndrome check result is
marked on an error_indicator field within each M/H service
data packet configuring a payload of the RS frame, so as to
be outputted for A/V decoding.
For example, the
error_indicator field of the M/H service data packet having
an error existing therein is marked as '1', and the
error_indicator field of the M/H service data packet having
no error existing therein is marked as '0'. According to the
embodiment of the present invention, if the error_indicator
field value of all M/H service data packets within the RS
frame payload is set to '0' and transmitted by the
transmitting system, then based upon the CRC syndrome check
result, only the error_indicator fields of the M/H service
data packet rows are marked as '1'.
[00708]
Thus, the probability of malfunctioning in blocks
receiving and processing M/H service data packets (e.g., TP
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handler 1133) in later processes may be reduced. For example,
the TP handler 1133 may discard any M/H service data packet
having the error indicator field marked as '1' without using
the corresponding M/H service data packet.
Accordingly,
since the probability of malfunctioning in the TP handler
1133 can be reduced, the overall performance of the receiving
system may be enhanced.
[00709]
Hereinafter, the error correction process shown in
FIG. 56 will now be described in detail.
[00710]
More specifically, when a (N+2)x(187+P)-byte size
RS frame and a (N+2)x(187+P)-bit size RE frame reliability
map are configured, as shown in (a) and (a') of FIG. 56, a
CRC syndrome check is performed on the RS frame, so as to
check whether or not an error has occurred in each row.
Subsequently, the presence or absence of an error is marked
on a CRC error flag corresponding to each row, as shown in
(b) of FIG. 56.
At this point, since the portion of the
reliability map corresponding to the CRC checksum as no
applicability, the corresponding portion is removed (or
deleted or discarded), so that only Nx(187+P) number of
reliability information remains, as shown in (b') of FIG. 56.
[00711]
As described above, after performing the CRC
syndrome check, (187+P, 187)-RS decoding is performed on N
number of columns. At this point, RS-decoding is performed
on only N number of columns excluding the last 2 columns from
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the overall (N+2) number of columns because the last 2
columns are configured only of CRC checksum and also because
the transmitting system did not perform RS-encoding on the
last 2 columns.
[00712]
At this point, depending upon the number of errors
marked on the CRC error flag, either an erasure decoding
process is performed or a general RS-decoding process is
performed.
[00713]
For example, when the number of rows including CRC
error is less than or equal to a maximum number of errors
correctable by RS erasure decoding (according to the
embodiment of the present invention, the maximum number is
'48'), (235,187)-RS erasure decoding is performed on the RS
frame having (18+P) number of N-byte rows, i.e., the RS frame
having 235 N-byte rows in a column direction, as shown in (d)
of FIG. 56.
However, when the number of rows including CRC
error is greater than the maximum number of errors (i.e., 48
errors) correctable by RS erasure decoding, RS erasure
decoding cannot be performed. In this case, error correction
may be performed through a general RS-decoding process.
Herein, the present invention may further enhance the error
correcting ability by using the reliability map, which was
generated when configuring the RS frame, from a soft decision
value.
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[00714] The detailed description on the operations of (c),
(d), and (d') of FIG. 55 may be directly applied to the
operations of (c), (d), and (d') of FIG. 56 without any
modification. Therefore, herein, the detailed description of
(c), (d), and (d') of FIG. 56 may be omitted for simplicity.
[00715] More specifically, the present invention may apply
the process (d) of FIG. 56 or the process (d') of FIG. 56, so
as to perform error correction decoding on N number of
columns excluding the last 2 columns within the RS frame.
[00716] After performing error correction decoding on the N
number of columns, the number of RS errors is counted as
shown in (e) of FIG. 56.
[00717] At this point, if an error did not occur in any of
the columns, or if all errors have been corrected in process
(d) of FIG. 56 or process (d') of FIG. 56, i.e., if the
number of RS errors is equal to '0', this indicates that
there is no error in the (N+187)-byte RS frame payload
configuring the M/H service data packet within the
corresponding RS frame. Herein, as shown in (f) of FIG. 56,
derandomizing is performed on the (N+187)-byte RS frame
payload as an inverse process of the transmitting system.
Thereafter, when outputting each M/H service data packet
(i.e., M/H TP packet) of the derandomized RS frame payload to
the TP handler 1133, the output is performed by setting the
value of the error indicator field within the M/H service
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data packet to '0' (i.e., indicating that there is no error),
as shown in (g) of FIG. 56. More specifically, the value of
the error indicator field within each of the M/H service data
packets configuring the RS frame payload is equally set to
'0'.
[00718] Meanwhile, even though RS-decoding is performed,
errors in N number of columns may all remain without being
corrected. In this case, the number of RS errors is not
equal to '0'.
[00719] In this case, as shown in (h) of FIG. 56, a CRC
syndrome check is performed once again on the RS-decoded RS
frame, thereby checking once again whether or not an error
exists in 187 rows.
[00720] The CRC syndrome check is repeated in (h) of FIG.
56 because, although RS-decoding has not been performed on
the last 2 columns (i.e., CRC checksum data) of the RS frame,
RS-decoding has been performed on the N number of columns
including M/H service data packet. Accordingly, the effects
(or influence) of the error corrected by RS-decoding may be
verified and reflected (or applied).
[00721] More specifically, after performing CRC-RS decoding,
when the present invention repeats the CRC syndrome check
process once again on each row, as shown in (h) of FIG. 56,
and derandomizes the RS frame payload processed with CRC
syndrome checking, as shown in (i) of FIG. 56, and when the
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present invention outputs the derandomized RS frame payload,
the present invention marks the CRC syndrome check result in
the error indicator field of the M/H service data packet
configuring the corresponding row, as shown in (j) of FIG. 56.
[00722] For example, when performing the CRC syndrome check
once again, if it is determined that there is not CRC error
in the RS frame, the value of the error_indicator field
within each M/H service data packet of the derandomized RS
frame payload is equally set to '0'.
[00723] When performing the CRC syndrome check once again,
if it is determined that a CRC error exists in a specific row
of the RS frame, for example, the second and third rows of
the RS frame, the values of the error indicator field within
the second and third M/H service data packets of the
derandomized RS frame payload are marked to be equal to '1',
and the value of the error indicator field within the
remaining M/H service data packets is equally marked to be
equal to '0'.
[00724] As described above, the transmitting system and the
receiving system and the broadcast signal processing method
of the same according to the present invention have the
following advantages. When transmitting mobile service data
through a channel, the present invention may be robust
against errors and backward compatible with the conventional
digital broadcast receiving system.
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[00725]
Moreover, the present invention may also receive
the mobile service data without any error even in channels
having severe ghost effect and noise.
[00726]
Furthermore, by inserting known data in a
particular position (or place) within a data region and
transmitting the processed data, the receiving performance of
the receiving system may be enhanced even in a channel
environment that is liable to frequent changes.
[00727]
By signaling the source IP address information of
the IP datagram varying the corresponding component in a
component loop of a service map table (SMT), the present
invention may be capable of acquiring the IP datagram of the
component with more accuracy.
[00728]
After performing CRC-RS decoding on the RS frame,
the CRC syndrome check is performed once again on the RS
frame, and the corresponding result is indicated in the
error indicator field of the M/H service data packets
configuring the payload of the RS frame, thereby being
outputted.
Thus, the possibility of malfunction of a block
receiving and processing the M/H service data packet may be
reduced, thereby enhancing the overall performance of the
receiving system.
[00729]
Finally, the present invention is even more
effective when applied to mobile and portable receivers,
which are also liable to a frequent change in channel and
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74420-522Dl
which require protection (or resistance) against intense noise.
[00730]
It will be apparent to those skilled in the art that
various modifications and variations can be made in the present
invention without departing from the scope of the inventions.
Thus, it is intended that the present invention covers the
modifications and variations of this invention provided they
come within the scope of the appended claims and their
equivalents.
255
