Note: Descriptions are shown in the official language in which they were submitted.
CA 02709121 2010-06-11
WO 2009/078638 PCT/KR2008/007406
Description
TRANSMITTING SYSTEM AND RECEIVING SYSTEM FOR
PROCESSING STREAM, AND STREAM PROCESSING
METHODS THEREOF
Technical Field
[1] The present invention relates generally to a transmitting system and a
receiving
system for transmitting, receiving and processing a stream, and processing
methods
thereof. More particularly, the present invention relates to a transmitting
system and a
receiving system for transmitting, receiving and processing a robust stream to
listen to
the stream even in a mobile environment, and processing methods of the
systems.
Background Art
[2] Based on advances of digital technologies, existing analog broadcasting
systems are
digitized by degrees. Naturally, countries are suggesting various digital
broadcasting
standards.
[3] Of the various digital broadcasting standards, Advanced Television System
Committee (ATSC) standard and Digital Video Broadcasting-Terrestrial (DVB-T)
standard are attracting much attention.
[4] The ATSC standard adopts 8-Vestigial Side Band (VSB) modulation, whereas
the
DVB-T standard adopts Coded Orthogonal Frequency Division Multiplex (COFDM)
scheme. Since the DVB-T standard is robust to a multi-path channel,
particularly, to
channel interference, it facilitates the implementation of Single Frequency
Network
(SFN).
[5] While the DVB-T standard has a difficulty in implementing High Definition
(HD)
broadcasting because of a low data rate, the ATSC standard is suitable for the
HD
broadcasting.
[6] As such, the respective standards have advantages and disadvantages. The
countries
are attempting to suggest an optimized standard by addressing the shortcomings
of the
standards.
[7] Meanwhile, in accordance with wide use of portable devices, the digital
broadcasting
can be viewed through the portable devices. Because of high mobility of the
portable
devices, a stream to be viewed at the portable device requires robust
processing,
compared to a normal stream.
[8] To separately constitute and transmit the robust stream, separate digital
broadcasting
and relay equipment are required mostly. What is needed is a method for
efficiently
transmitting the robust stream using the existing digital facilities.
Brief Description of the Drawings
2
WO 2009/078638 PCT/KR2008/007406
[9] These and/or other aspects and advantages of the invention will become
apparent and
more readily appreciated from the following description of the embodiments,
taken in
conjunction with the accompanying drawings of which:
[10] FIG. 1 is a block diagram of a transmitting system according to an
exemplary em-
bodiment of the present invention;
[11] FIG. 2 is a detailed block diagram of the transmitting system according
to an
exemplary embodiment of the present invention;
[12] FIGS. 3 through 8 are diagrams of various streams output from an adaptor
of the
transmitting system of FIG. 1 or FIG. 2;
[13] FIG. 9 is a block diagram of a transmitting system according to another
exemplary
embodiment of the present invention;
[14] FIG. 10 is a block diagram of an exciter in a transmitting system
according to yet
another exemplary embodiment of the present invention;
[15] FIG. 11 is a block diagram of a receiving system according to an
exemplary em-
bodiment of the present invention;
[16] FIG. 12 is a detailed block diagram of the receiving system according to
an
exemplary embodiment of the present invention;
[17] FIG. 13 is a flowchart outlining a stream processing method of the
transmitting
system according to an exemplary embodiment of the present invention;
[18] FIG. 14 is a flowchart outlining a stream processing method of the
transmitting
system according to another exemplary embodiment of the present invention; and
[19] FIG. 15 is a flowchart outlining a stream processing method of the
receiving system
according to an exemplary embodiment of the present invention.
Best Mode for Carrying Out the Invention
[20] An aspect of the present invention has been provided to solve the above-
mentioned
and/or other problems and disadvantages and an aspect of the present invention
provides a transmitting system and a receiving system for efficiently
inserting a robust
stream into a transport stream in various patterns, transmitting, receiving,
and
processing the stream, and stream processing methods thereof.
[21] Additional aspects and/or advantages of the invention will be set forth
in part in the
description which follows and, in part, will be obvious from the description,
or may be
learned by practice of the invention.
[22] According to an aspect of the present invention, a transmitting system
includes an
adaptor for, when receiving a first stream, making a space in the first stream
to insert a
second stream; a Reed-Solomon (RS) encoder for RS-encoding the input second
stream; a Cyclic Redundancy Check (CRC) processor for converting the RS-
encoded
second stream to a stream comprising an added CRC bit sequence; and a stuffer
for
CA 02709121 2010-06-11
3
WO 2009/078638 PCT/KR2008/007406
inserting the stream to the space in the first stream and outputting a
transport stream.
[23] The transmitting system may further include a randomizer for randomizing
the input
second stream and providing the randomized second stream to the RS encoder; a
byte
interleaver for interleaving the second stream RS-encoded at the RS encoder
byte by
byte and providing the interleaved stream to the CRC processor; an outer
encoder for
encoding the stream converted at the CRC processor; an outer interleaver for
in-
terleaving the outer-encoded stream; and a packet formatter for formatting the
in-
terleaved stream and providing the formatted stream to the stuffer.
[24] The transmitting system may further include a sequence processor for
outputting a
sequence known to a receiving system; and a packet formatter for formatting
the
stream and the sequence respectively and providing the stream and the sequence
to the
stuffer.
[25] The packet formatter may format the stream in one of a first format
comprising a
sync signal, a packet IDentifier (ID), and second stream data, a second format
comprising a packet ID and second stream data, and a third format comprising
only
second stream data. The packet ID may be a null value or a new ID
unrecognizable by
a normal decoder of the receiving system.
[26] The transmitting system may further include an exciter for processing the
transport
stream output from the stuffer and transmitting the transport stream over a
radio
channel.
[27] The exciter may include a sequence processor for inserting a sequence
known to a
receiving system in the transport stream.
[28] The exciter may further include an Advanced Television System Committee
(ATSC)
randomizer for randomizing the transport stream; an ATSC RS encoder for RS-
encoding the randomized transport stream and providing the RS-encoded stream
to the
sequence processor; an ATSC CV interleaver for convolutionally interleaving
the
transport stream output from the sequence processor; a trellis encoder for
trellis-
encoding the convolutionally interleaved transport stream, resetting memories
at a
preset time, and correcting a parity of the transport stream in accordance
with the
memory reset; and a multiplexer (MUX) for inserting a sync signal to the
transport
stream output from the trellis encoder.
[29] The adaptor may make the space in one of a first pattern which makes the
space for
one packet per four packets, a second pattern which makes the spaces for two
packets
per four packets, a third pattern which makes the spaces for three packets per
four
packets, a fourth pattern which makes the space for one packet per two
packets, and a
fifth pattern which makes the spaces for a plurality of successive packets.
[30] According to the aspect of the present invention, a receiving system
includes a robust
stream processor for, upon receiving a transport stream, detecting a robust
stream from
CA 02709121 2010-06-11
4
WO 2009/078638 PCT/KR2008/007406
the transport stream and trellis-decoding the robust stream; a Cyclic
Redundancy
Check (CRC) detector for checking for error based on CRC bits of the stream
output
from the robust stream processor; a Reed-Solomon (RS) decoder for RS-decoding
the
stream using the error check result of the CRC detector; and a derandomizer
for deran-
domizing the RS-decoded stream.
[31] The receiving system may further include a synchronizer for synchronizing
the
received transport stream; an equalizer for equalizing the synchronized
transport
stream using a known sequence in the received transport stream and providing
the
equalized stream to the robust stream processor; and a byte deinterleaver for
dein-
terleaving the stream output from the CRC detector byte by byte and providing
the
deinterleaved stream to the RS decoder.
[32] The transport stream may be constituted in one of a first pattern which
makes the
space for one packet per four packets, a second pattern which makes the spaces
for two
packets per four packets, a third pattern which makes the spaces for three
packets per
four packets, a fourth pattern which makes the space for one packet per two
packets,
and a fifth pattern which makes the spaces for a plurality of successive
packets to
insert the robust stream.
[33] According to the aspect of the present invention, a stream processing
method of a
transmitting system includes when receiving a first stream, making a space in
the first
stream to insert a second stream; when receiving the second stream, Reed-
Solomon
(RS)-encoding the second stream; Cyclic Redundancy Check (CRC) processing to
convert the RS-encoded second stream to a stream comprising an added CRC bit
sequence; and constituting a transport stream by inserting the stream to the
space in the
first stream.
[34] The stream processing method may further include formatting a sequence
known to a
receiving system and inserting the known sequence in the space of the first
stream.
[35] The stream processing method may further include before RS encoding,
randomizing
the input second stream; before CRC processing, interleaving the RS-encoded
second
stream byte by byte; encoding the stream converted in the CRC processing; in-
terleaving the encoded stream; and formatting the interleaved stream to insert
the
formatted stream into the space of the first stream.
[36] The formatting of the interleaved stream may format the stream in one of
a first
format comprising a sync signal, a packet IDentifier (ID), and second stream
data, a
second format comprising a packet ID and second stream data, and a third
format
comprising only second stream data.
[37] The packet ID may be a null value or a new ID unrecognizable by a normal
decoder
of a receiving system.
[38] The stream processing method may further include randomizing the
constituted
CA 02709121 2010-06-11
5
WO 2009/078638 PCT/KR2008/007406
transport stream; RS-encoding the randomized transport stream; inserting a
sequence
known between a receiving system into the RS-encoded transport stream; convolu-
tionally interleaving the transport stream comprising the known sequence;
trellis-
encoding the convolutionally interleaved transport stream, resetting memories
at a
preset time, and correcting a parity of the transport stream in accordance
with the
memory reset; and inserting a sync signal to the trellis-encoded transport
stream and
transmitting the stream over a radio channel.
[391 The making of the space to inserting the second stream in the first
stream may make
the space in one of a first pattern which makes the space for one packet per
four
packets, a second pattern which makes the spaces for two packets per four
packets, a
third pattern which makes the spaces for three packets per four packets, a
fourth
pattern which makes the space for one packet per two packets, and a fifth
pattern
which makes the spaces for a plurality of successive packets.
[401 According to the aspect of the present invention, a stream processing
method of a
receiving system includes when receiving a transport stream, robustly
processing the
stream by detecting a robust stream from the transport stream and trellis-
decoding the
robust stream; Cyclic Redundancy Check (CRC)-detecting by checking for error
based
on CRC bits of the robust stream; Reed-Solomon (RS)-decoding the stream using
the
error check result; and derandomizing the RS-decoded stream.
[411 The stream processing method may further include synchronizing the
received
transport stream; before the robustly processing the stream, equalizing the
syn-
chronized transport stream using a known sequence in the received transport
stream;
and before RS-decoding, deinterleaving the stream processed in the CRC
detecting
byte by byte.
[421 The transport stream may be constituted in one of a first pattern which
makes the
space for one packet per four packets, a second pattern which makes the spaces
for two
packets per four packets, a third pattern which makes the spaces for three
packets per
four packets, a fourth pattern which makes the space for one packet per two
packets,
and a fifth pattern which makes the spaces for a plurality of successive
packets to
insert the robust stream.
[431 In various embodiments of the present invention, the stream can be
processed more
robustly and transceived. The robust stream can be efficiently inserted to the
transport
stream in diverse patterns. Therefore, the general digital broadcasting
receiver can
receive and process the normal stream, and the portable device can receive and
process
the robust stream at the same time. In addition, the equalization performance
can be
enhanced by means of the known sequence.
[441 Additional and/or other aspects and advantages of the invention will be
set forth in
part in the description which follows and, in part, will be obvious from the
description,
CA 02709121 2010-06-11
6
WO 2009/078638 PCT/KR2008/007406
or may be learned by practice of the invention.
Mode for the Invention
[45] Reference will now be made in detail to the embodiment of the present
general
inventive concept, examples of which are illustrated in the accompanying
drawings,
wherein like reference numerals refer to the like elements throughout. The
embodiment
is described below in order to explain the present general inventive concept
by
referring to the drawings.
[46] FIG. 1 is a block diagram of a transmitting system according to an
exemplary em-
bodiment of the present invention. The transmitting system of FIG. 1 includes
an
adaptor 110, a stuffer 120, a Reed-Solomon (RS) encoder 130, and a Cyclic Re-
dundancy Check (CRC) processor 140.
[47] The adaptor 110 receives a first stream and generates a space for
inserting a second
stream in the first stream. To make the space, the adaptor 110 may generate an
adaptation field in each packet of the first stream or use a payload of the
packet as the
space. Herein, the first stream can be a general broadcasting signal
transceived and
processed at the existing broadcasting system; that is, a normal stream. The
adaptor
110 makes the space in the first stream with a preset pattern, which will be
further
explained in reference to FIGS. 3 through 8.
[48] The RS encoder 130 receives and RS-encodes the second stream. Herein, the
second
stream indicates a stream processed differently from the first stream. In more
detail, the
second stream can be a robust stream (or turbo stream or Advanced Vestigial
Side
Band (AVSB) stream) robustly processed to be received at a portable device.
The
second stream can be input from a source different from the first stream as
the robust
stream, or received from the same source as the same stream and robustly
processed at
the RS encoder 130 and the CRC processor 140.
[49] The CRC processor 140 converts the RS-encoded second stream to a stream
including a CRC bit sequence. The CRC processor 140 shifts data of the second
stream
by the number of Frame Check Sequence (FCS) bits, divides the data by a
predefined
generator polynomial, and acquires the remainder. The CRC processor 140 adds
the
acquired remainder; that is, the CRC bit sequence (or the FCS) to the second
stream,
and provides the stream to the stuffer 120.
[50] The stuffer 120 inserts the stream output from the CRC processor 140 into
the first
stream output from the adaptor 110. That is, the second stream including the
CRC bit
sequence is inserted in the space of the first stream. Thus, a transport
stream including
both the first stream and the second stream is generated.
[51] As both of the RS encoder 130 and the CRC processor 140 lie in the second
stream
processing path in FIG. 1, the second stream is processed more robustly and
then
CA 02709121 2010-06-11
7
WO 2009/078638 PCT/KR2008/007406
transmitted. Thus, various wireless mobile devices can effectively receive and
process
the stream.
[52] FIG. 2 is a detailed block diagram of the transmitting system according
to an
exemplary embodiment of the present invention. In addition to the adaptor 110,
the
stuffer 120, the RS encoder 130, and the CRC processor 140, the transmitting
system
of FIG. 2 can further include a randomizer 150, a byte interleaver 160, an
outer
encoder 170, an outer interleaver 180, a packet formatter 190, and an exciter
200. Note
that the arrangement order of the components can vary, some of the components
can be
omitted, and components not illustrated in FIG. 2 can be further provided in
various
embodiments.
[53] As in FIG. 1, the adaptor 110 makes the space in the first stream. The
stuffer 120
constitutes the transport stream by inserting the second stream; that is, the
robust
stream in the space of the first stream. The robust stream can be processed
through the
randomizer 150, the RS encoder 130, the byte interleaver 160, the CRC
processor 140,
the outer encoder 170, the outer interleaver 180, and the packet formatter
190, and then
provided to the stuffer 120.
[54] The randomizer 150 randomizes the second stream fed from an external
source. The
RS encoder 130 RS-encodes the randomized second stream. In the RS encoding,
various coding rates can be applied.
[55] The byte interleaver 160 interleaves the RS-encoded second stream byte by
byte. The
CRC processor 140 calculates and adds the CRC bit sequence to the bytewise in-
terleaved second stream.
[56] The outer encoder 170 and the outer interleaver 180 outer-encodes and
outer-
interleaves the stream output from the CRC processor 140.
[57] The packet formatter 190 converts a packet format so that the outer-
interleaved
stream can be easily inserted to the first stream. The packet generally
includes a sync, a
packet IDentifier (ID), and a payload.
[58] When the adaptor 110 ensures one entire packet, the packet formatter 190
formats the
stream in a format including all of the sync, the packet ID, and the second
stream data
(hereafter, referred to as a first format). When the adaptor 110 empties only
the packet
ID and the payload, the packet formatter 190 formats the stream in a format
including
the packet ID and the second stream data (hereafter, referred to as a second
format).
When the adaptor 110 empties only the payload, the packet formatter 190
formats the
stream in a format including only the second stream data (hereafter, referred
to as a
third format).
[59] The second stream does not target the conventional digital receive
stream. To avoid
data cross, it is preferable that the packet formatter 190 should assign a
null value for
the packet ID of the second data stream, or use a new ID unrecognizable by a
normal
CA 02709121 2010-06-11
8
WO 2009/078638 PCT/KR2008/007406
decoder (not shown) of the receiving system.
[60] The stream converted in the proper format is inserted to the first stream
at the stuffer
120, to thus generate the transport stream.
[61] The exciter 200 properly processes the transport stream output from the
stuffer 120
and transmits the transport stream over a radio channel. The exciter 200 can
include an
Advanced Television System Committee (ATSC) randomizer 210, an ATSC RS
encoder 220, an ATSC CV interleaver 230, a trellis encoder 240, and a
multiplexer
(MUX) 250 as shown in FIG. 2.
[62] The ATSC randomizer 210 randomizes the transport stream. The ATSC RS
encoder
220 RS-encodes the randomized transport stream.
[63] The ATSC CV interleaver 230 convolutionally interleaves the RS-encoded
transport
stream. In further detail, the ATSC CV interleaver 230 interleaves the bits of
the
transport stream by storing the transport stream to a plurality of memory
elements
having different lengths in sequence and sequentially outputting the transport
stream.
[64] The trellis encoder 240 trellis-encodes the convolutionally interleaved
transport
stream. When a known sequence is inserted to and transmitted together with the
first
stream, the sequence is highly likely to be changed by initial values pre-
stored to
memories of the trellis encoder 240. To avoid this, the trellis encoder 240
resets the
memories at a preset time point. Since a parity bit is already added to the
transport
stream through the RS encoding at the ATSC RS encoder 220, it is preferable
that the
trellis encoder 240 should correct the parity according to the changed values
in the
memory resetting.
[65] The MUX 250 inserts a sync signal to the transport stream output from the
trellis
encoder 240. The sync signal can employ a field sync signal, a segment sync
signal,
and so forth.
[66] The transport stream including the sync signal is channel-modulated at a
modulator
(not shown), up-converted to a Radio Frequency (RF) signal, and then
transmitted via
an antenna over the radio channel.
[67] FIGS. 3 through 8 depict various transport streams according to various
em-
bodiments of the present invention.
[68] The adaptor 110 of the transmitting system makes a space for the second
stream per
four packets as shown in FIG. 3. In FIGS. 3 through 8, the first stream is the
normal
stream and the second stream is Mobile/Handheld (M/H) data provided to an M/H
device by way of example.
[69] The adaptor 110 may empty one entire packet, or other packet regions
excluding
SYNC or PID, for the second stream. The PID of the packet with the M/H data
inserted
uses PID(1) which is distinguished from the PID of the packet including the
normal
stream. The PID(1) indicates a packet ID unrecognizable by the normal stream.
The
CA 02709121 2010-06-11
9
WO 2009/078638 PCT/KR2008/007406
PID(1) and the format of the M/H data can be constituted by the packet
formatter 190.
[70] The adaptor 110 may make two spaces for the second stream per four
packets as
shown in FIGS. 4 and 5. As one can see in FIGS. 4 and 5, the packet order can
vary.
[71] The adaptor 110 may make three spaces for the second stream per four
streams as
shown in FIG. 6, or make a space for the second stream per two streams; that
is, make
the spaces for inserting the first and second streams in alternation as shown
in FIG. 7.
[72] The adaptor 110 may entirely empty n-ary packet regions and use them as
the space
for the second stream as shown in FIG. 8. For example, when the normal streams
are
not input for a certain time duration or when there is no need to output the
streams in
succession, the adaptor 110 can arrange the space to insert the M/H data into
the
successive packets as shown in FIG. 8.
[73] As such, the transport stream can be constituted in various patterns in
the
transmitting system.
[74] FIG. 9 is a block diagram of a transmitting system according to another
exemplary
embodiment of the present invention. The transmitting system of FIG. 9 can
include an
adaptor 110, a stuffer 120, an RS encoder 130, a CRC processor 140, a packet
formatter 190, a sequence processor 195, and an exciter 200.
[75] The components, excluding the sequence processor 195, are substantially
the same as
in FIGS. 1 and 2 and shall not be explained here.
[76] The sequence processor 195 provides the sequence known between the
receiving
system to the packet formatter 190. Herein, the known sequence can be a
reference
signal used for channel synchronization or equalization at the receiving
system. More
specifically, the known sequence can be a Supplementary Reference Signal
(SRS).
[77] The packet formatter 190 formats the sequence fed from the sequence
processor 195
and provides the formatted sequence to the stuffer 120.
[78] In the end, the stuffer 120 inserts the second stream robustly processed
through the
RF encoder 130 and the CRC processor 140 and the sequence processed through
the
sequence processor 195 into the first stream, thereby configuring a transport
stream.
[79] The sequence processor 195 may be located at a front end of the stuffer
120 as shown
in FIG. 9, or may be located in the exciter 200.
[80] FIG. 10 is a block diagram of an exciter including a sequence processor.
Referring to
FIG. 10, the exciter 200 can include an ATSC randomizer 210, an ATSC RS
encoder
220, a sequence processor 260, an ATSC CV interleaver 230, a trellis encoder
240, and
a multiplexer (MUX).
[81] The ATSC randomizer 210 randomizes the transport stream configured by the
stuffer
120, and the ATSC RS encoder 220 encodes the randomized transport stream.
[82] The sequence processor 260 inserts the above-described sequence into a
space
provided in the encoded transport stream. The ATSC CV interleaver 230
interleaves
CA 02709121 2010-06-11
10
WO 2009/078638 PCT/KR2008/007406
the transport stream into which the sequence is inserted and provides the
interleaved
transport stream to the trellis encoder 240.
[83] The trellis encoder 240 includes a parity substituter 241, a trellis
encoder 242, and an
RS re-encoder 243.
[84] The trellis encoder 242 trellis-encodes the transport stream. The trellis
encoder 242
may consist of 12 trellis encoding modules. Accordingly, the trellis encoding
modules
are selected from 1st to 12th in sequence and continuously according to
received
packets, and output respective trellis encoding values.
[85] Each of the trellis encoding modules may include a plurality of
multiplexers
(MUXs), a plurality of memories, and a plurality of adders. The memories are
co-
operated in a shift manner.
[86] The trellis encoder 242 initializes memories of each of the trellis
encoding modules
before a known sequence part of the interleaved transport stream is input.
Since the
trellis encoder 242 includes a plurality of memories, a current input value is
affected
by a previous input value. Accordingly, there is a possibility that the known
sequence
value changes, and, in order to prevent the change in the sequence, the
memories are
initialized before the sequence is input.
[87] More specifically, before a sequence interval is input, the trellis
encoder 242 sub-
stitutes an input value of about 2 bit interval (hereinafter, referred to as a
2bit input
interval) for the same value as a value pre-stored in each memory of each
trellis
encoding module, and performs a OR operation so that each memory can be re-set
for
the 2 bit input interval.
[88] The trellis encoder 242 provides the values pre-stored in the memories to
the RS re-
encoder 243 to correct parity.
[89] The RS re-encoder 243 generates a parity bit for the provided values and
provides the
parity bit to the parity substituter 241.
[90] The parity substituter 241 substitutes the parity bit corresponding to
the 2bit input
interval with the parity bit provided by the RS re-encoder 243 to correct the
parity.
That is, since the input value of a 2 bit input interval changes by the
trellis encoder 242
after having been already encoded by the ATSC RS encoder 220, the parity
should be
corrected according to the changed value.
[91] As described, the trellis encoder 240 is operated in a general mode to
trellis-encode
packets of an incoming transport stream and in a parity correction mode to
correct
parity subsequent to the initialization.
[92] The MUX 250 is provided with the transport stream trellis encoded with
parity being
corrected, and multiplexes field sync and segment sync. A modulator or a power
amplifier may be provided on a rear end of the MUX 250, but their detailed
description
will be omitted since they are well known to the related art.
CA 02709121 2010-06-11
11
WO 2009/078638 PCT/KR2008/007406
[93] FIG. 11 is a block diagram of a receiving system according to an
exemplary em-
bodiment of the present invention. The receiving system of FIG. 11 includes a
robust
stream processor 310, a CRC detector 320, an RS decoder 330, and a
derandomizer
340.
[94] The robust stream processor 310 detects the robust stream; that is, the
second stream
from the transport stream received over the antenna and trellis-decodes the
detected
stream.
[95] The CRC detector 320 checks for error based on the CRC bits of the stream
output
from the robust stream processor 310.
[96] The RS decoder 330 RS-decodes the stream using the check result of the
CRC
detector 320. Since the CRC detector 320 locates the error using the CRC bit
sequence,
the decoding efficiency of the RS decoder 330 can be enhanced.
[97] The derandomizer 340 restores the second stream by derandomizing the RS-
decoded
stream.
[98] The receiving system may further include separate components for
processing the
normal stream. In this case, the receiving system can receive one transport
stream and
recover the normal stream and the M/H stream all together by processing the
transport
stream in two paths.
[99] FIG. 12 is a detailed block diagram of the receiving system of FIG. 11.
The receiving
system of FIG. 12 can further include a synchronizer 350 and an equalizer 360
in front
of the robust stream processor 310, and a byte deinterleaver 370 in between
the CRC
detector 320 and the RS decoder 330. Although it is not depicted in the
drawing, the
receiving system may further include a demodulator.
[100] The synchronizer 350 detects and acquires synchronization from the
received
transport stream, and provides the transport stream to the equalizer 360.
[101] The equalizer 360 cancels interference between the received symbols by
equalizing
the input transport stream and compensating for a channel distortion caused by
the
channel multipath. For the equalization, the equalizer 360 can detect and use
the
known sequence inserted in the transport stream.
[102] The robust stream processor 310 includes a TCM decoder 311, a CV
deinterleaver
312, an outer deinterleaver 313, an outer decoder 314, an outer interleaver
315, and a
CV interleaver 316.
[103] The TCM decoder 311 detects the second stream from the equalized
transport stream
and trellis-decodes the second stream.
[104] The CV deinterleaver 312 convolutionally deinterleaves the trellis-
decoded second
stream. The outer deinterleaver 313 outer-deinterleaves the second stream. The
outer
decoder 314 removes the parity bit from the second stream by decoding the
second
stream.
CA 02709121 2010-06-11
12
WO 2009/078638 PCT/KR2008/007406
[105] The outer decoder 314 can output a soft decision value or a hard
decision value
according to the decoding result. Upon the hard decision, the second stream is
output
to the CRC detector 320. Upon the soft decision, the outer interleaver 315
interleaves
the second stream and provides the interleaved second stream to the CV
interleaver
316.
[106] The CV interleaver 316 convolutionally interleaves the second stream and
outputs
the interleaved second stream to the TCM decoder 311. As such, the trellis
decoding is
repeated until the hard decision is produced, to thus attain the reliable
decoding value.
[107] Alternatively, without using the hard decision value and the soft
decision value, the
trellis decoding may be set to repeat for a preset number of times.
[108] The trellis-decoded second stream is fed to the CRC detector 320.
[109] The CRC detector 320 locates error by detecting the CRC bit sequence.
[110] The byte deinterleaver 370 deinterleaves the output of the CRC detector
320 byte by
byte.
[111] The RS decoder 330 RS-decodes the stream output from the byte
deinterleaver 370.
The derandomizer 340 recovers the data of the second stream by derandomizing
the
second stream.
[112] FIG. 13 is a flowchart outlining a stream processing method of the
transmitting
system according to an exemplary embodiment of the present invention. The
transmitting system individually receives the first stream and the second
stream, makes
the space in the first stream to insert the second stream (S 1310), and RS-
encodes the
second stream (S1320).
[113] Herein, the space can be the adaptation field in the first stream, or
the entire packet
payload.
[114] Next, the transmitting system CRC-processes the RS-encoded second stream
(S 1330). That is, the CRC bit sequence for the second stream is calculated
and
appended.
[115] Separately, the known sequence can be processed. The transmitting system
receives
and formats the sequence commonly known between the receiving system (S 1340).
[116] The transmitting system constitutes the transport stream by inserting
the second
stream including the CRC bit sequence into the first stream and the formatted
sequence
(S 1350).
[117] As stated above, the system for transmitting the first stream processed
in the typical
manner; that is, the normal stream can send the second stream robustly
processed; that
is, the robust stream together with the known sequence.
[118] In various implementations of the present invention, the stream
processing method of
FIG. 13 can further include a randomizing step, a byte interleaving step, an
outer
encoding step, and a packet formatting step. The temporal order of some steps
may be
CA 02709121 2010-06-11
13
WO 2009/078638 PCT/KR2008/007406
changed.
[119] FIG. 14 is a flowchart outlining a stream processing method of the
transmitting
system according to another exemplary embodiment of the present invention. The
transmitting system makes the space in the first stream (S 1410), separately
receives the
second stream (S 1415), and performs the randomizing (S 1415), the RS-encoding
(S 1420), the bytewise interleaving (S 1425), the CRC processing (S 1430), the
encoding
(S 1435), the interleaving (S 1440), and the packet formatting (51445) on the
second
stream in that order. The respective steps have been illustrated in FIG. 2 and
shall not
be further described. Although the making of the space in the first stream (S
1410)
precedes the other steps, the step S 1410 is separately conducted and
accordingly the
order of the steps can be altered.
[120] Next, the transmitting system stuffs the space of the first stream with
the formatted
second stream (S1450).
[121] Hence, when the transport stream is constituted, the transmitting system
randomizes
(S 1455) the transport stream and RS-encodes the transport stream (S 1460).
[122] Next, the transmitting system inserts the sequence to the RS-encoded
transport
stream (S1465). The inserted sequence is commonly known to the receiving
system
and can be the SRS.
[123] Upon completing the sequence insertion, the transmitting system
convolutionally in-
terleaves the transport stream (51470) and trellis-encodes the interleaved
transport
stream (S1475).
[124] The transmitting system multiplexes the transport stream with the sync
signals
(S 1480) and transmits the stream after the modulation and the amplification.
[125] FIG. 15 is a flowchart outlining a stream processing method of the
receiving system
according to an exemplary embodiment of the present invention.
[126] Upon receiving the transport stream (S1510), the receiving system
synchronizes the
received transport stream (S 1520) and equalizes the synchronized transport
stream
(S 1530).
[127] The receiving system detects the robust stream; that is, the second
stream from the
equalized transport stream and conducts the robust stream processing on the
second
stream (S1540). The robust stream processing has been described in detail in
FIG. 12
and shall not be further explained.
[128] After the robust stream processing, the receiving system detects the CRC
bit
sequence from the processed stream (S 1550) and deinterleaves the stream byte
by byte
(S 1560).
[129] The receiving system recovers the robust stream by RS-decoding (51570)
and deran-
domizing (S1580).
[130] Thus, even a wireless device frequently moving around can receive the
robust
CA 02709121 2010-06-11
14
WO 2009/078638 PCT/KR2008/007406
stream.
[1311 Although a few embodiments of the present general inventive concept have
been
shown and described, it will be appreciated by those skilled in the art that
changes may
be made in these embodiments without departing from the principles and spirit
of the
general inventive concept, the scope of which is defined in the appended
claims and
their equivalents.
CA 02709121 2010-06-11
