Note: Descriptions are shown in the official language in which they were submitted.
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Description
DIGITAL BROADCASTING RECEIVER AND METHOD FOR
CONTROLLING THE SAME
Technical Field
[1] The present invention relates to a digital broadcasting system, and
more particularly, to a digital broadcast receiving system and a method for
controlling the same.
Background Art
[2] A digital broadcasting system is configured of a digital broadcast
transmitting system (or transmitter) and a digital broadcast receiving system
(or
receiver). Also, the digital broadcast transmitting system digitally processes
data,
such as broadcast programs, and transmits the processed data to the digital
broadcast receiving system. Due to its various advantages, such as efficient
data
transmission, the.digital broadcasting system is gradually replacing the
conventional analog broadcasting systems.
[3] However, 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.
[4] Moreover, in a conventional mobile digital broadcasting environment,
it is the current reality that there is no concrete technology for setting or
releasing
a conditional access to a specific service.
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Disclosure of Invention
[5] Accordingly, embodiments of the present invention are directed
to a
digital broadcast receiver and a control method thereof that substantially
obviates
one or more problems due to limitations and disadvantages of the related art.
[6] An object of some embodiments of the present invention is to
provide a digital broadcast receiver which is robust against a channel
variation
and noise, and a control method thereof.
[7] Another object of some embodiments of the present invention is to
provide a data pr6cessing method which is capable of setting or releasing a
conditional access to a specific service in a mobile digital broadcasting
environment.
[8] Additional advantages, objects, and features of embodiments of the
invention will be set forth in part in the description which follows and in
part will
become apparent to those having ordinary skill in the art upon examination of
the
following or maybe learned from practice of the invention. The objectives and
other advantages of embodiments of the invention may be realized and attained
by the structure particularly pointed out in the written description and
claims hereof
as well as the appended drawings.
According to an aspect of the present invention, there is provided a
method of processing data for a receiver, the method comprising: receiving, by
a
receiving unit, a broadcast signal comprising fast information channel (FIC)
data
including cross layer information for mobile service acquisition, transmission
parameter channel (TPC) data including FIC version information for identifying
an
update of the FIC data, and mobile service data, wherein the mobile service
data
are packaged into a Reed-Solomon (RS) frame which belongs to an ensemble;
demodulating, by a demodulator, the broadcast signal; forming, by a processor,
the ensemble from the demodulated broadcast signal and acquiring a service map
table (SMT) from the ensemble, the SMT including IP access information and
encryption information of the mobile service data; and decrypting, by the
processor, the mobile service data included in the ensemble in accordance with
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the IP access information and the encryption information of the mobile service
data, wherein
the SMT further includes IP access information for accessing to IP datagram of
key
information for decryption of the mobile service data.
[8b] According to another aspect of the present invention, there is
provided a receiver
comprising: a receiving unit for receiving a broadcast signal comprising fast
information channel
(FIC) data including cross layer information for mobile service acquisition,
transmission
parameter channel (TPC) data including FIC version information for identifying
an update of the
FIC data, and mobile service data, wherein the mobile service data are
packaged into a Reed-
Solomon (RS) frame which belongs to an ensemble; a demodulator for
demodulating the
broadcast signal; a processor for forming the ensemble from the demodulated
broadcast signal and
acquiring a service map table (SMT) from the ensemble, the SMT including IP
access information
and encryption information of the mobile service data and decrypting the
mobile service data
included in the ensemble in accordance with the IP access information and the
encryption
information of the mobile service data, wherein the SMT further includes IP
access information
for accessing to IP datagram of key information for decryption of the mobile
service data.
[8c] According to another aspect of the present invention, there is
provided a method for
processing a digital broadcast signal, the method comprising: encoding
signaling data
including transmission parameter channel data and fast information channel
data; performing
a FEC (Forward Error Correction) coding on broadcast service data; generating
a data unit
including the FEC encoded broadcast service data, wherein the transmission
parameter
channel data contains a transmission parameter for signaling the digital
broadcast signal, and
wherein the fast information channel data contains information for rapid
broadcast service
scan and acquisition; and transmitting the digital broadcast signal including
the data unit and
the signaling data, wherein the digital broadcast signal further includes a
service map
information containing attributes for a broadcast service, wherein the service
map information
includes service identification information identifying the broadcast service.
[9] According to another aspect, a control method of a digital
broadcast receiver
includes the steps of receiving a broadcast signal into which mobile service
data and main service
data are multiplexed, extracting transmission parameter channel (TPC)
signaling information and
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receives a broadcast signal into which mobile service data and main service
data
are multiplexed. The extractor extracts transmission parameter channel
signaling
information and fast information channel signaling information from a data
group in
the received mobile service data. The acquirer acquires a program table
describing virtual channel information and a service of an ensemble by using
the
extracted fast information channel signaling information, the ensemble being a
virtual channel group of the received mobile service data. The detector
detects a
conditional access descriptor indicating whether the mobile service data was
encrypted by using the acquired program table. And the controller controls
such
that the encrypted mobile service data is decrypted by using information of
the
detected conditional access descriptor.
[11] In a further aspect, a control method of a digital broadcast
transmitter includes the steps of generating a broadcast signal including a
conditional access descriptor indicating whether mobile service data was
encrypted, and transmitting the generated broadcast signal including the
conditional access descriptor to a digital broadcast receiver side, wherein
the
conditional access descriptor includes information identifying respective
levels at
which the mobile-service data was encrypted, and information about control
data
which is used for decryption of the encrypted mobile service data.
[12] It is to be understood that both the foregoing general description and
the following detailed description of the present invention are exemplary and
explanatory and are intended to provide further explanation of the invention
as
claimed. =
[13] According to one embodiment of the present invention, it is possible
to provide a digital broadcast receiver which is robust against a channel
variation
and noise, and a control method thereof.
[14] Further, according to another embodiment of the present invention, it
is possible to readily implement a function of setting or releasing a
conditional
access to a specific service in a mobile digital broadcasting environment.
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[15] Moreover, according to a further embodiment of the present
invention, it is possible to control about transmission of a service with an
illegal
copy prevention function to an external interface in a mobile digital
broadcasting
environment.
Brief Description of the Drawings
[16] FIG. 1 illustrates a block diagram showing a structure of a digital
broadcasting receiving system according to an embodiment of the present
invention.
[17] FIG. 2 illustrates an exemplary structure of a data group according to
an embodiment of the present invention.
[18] FIG. 3 illustrates an RS frame according to an embodiment of the
present invention.
[19] FIG. 4 illustrates an example of an MH frame structure for
transmitting and receiving mobile service data according to an embodiment of
the
present invention.
[20] FIG. 5 illustrates an example of a general VSB frame structure.
[21] FIG. 6 illustrates an example of mapping positions of the first 4
slots
of a sub-frame in a spatial area with respect to a VSB frame.
[22] FIG. 7 illustrates an example of mapping positions of the first 4
slots
of a sub-frame in a chronological (or time) area with respect to a VSB frame.
[23] FIG. 8 illustrates an exemplary order of data groups being assigned
to one of 5 sub-frames configuring an MH frame according to an embodiment of
the present invention.
[24] FIG. 9 illustrates an example of a single parade being assigned to an
MH frame according to an embodiment of the present invention.
[25] FIG. 10 illustrates an example of 3 parades being assigned to an MH
frame according to an embodiment of the present invention.
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[26] FIG. 11 illustrates an example of the process of assigning 3 parades
shown in FIG. 10 being expanded to 5 sub-frames within an MH frame.
[27] FIG. 12 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.
[28] FIG. 13 illustrates a hierarchical signaling structure according to an
embodiment of the present invention.
[29] FIG. 14 illustrates an exemplary FIC body format according to an
embodiment of the present invention.
[30] FIG. 15 illustrates an exemplary bit stream syntax structure with
respect to an FIC segment according to an embodiment of the present invention.
[31] FIG. 16 illustrates an exemplary bit stream syntax structure
with
respect to a payload of an FIC segment according to an embodiment of the
present invention, when an FIC type field value is equal to '0'.
[32] FIG. 17 illustrates an exemplary bit stream syntax structure of a
service map table according to an embodiment of the present invention.
[33] FIG. 18 illustrates an exemplary bit stream syntax structure of an MH
audio descriptor according to an embodiment of the present invention.
[34] FIG. 19 illustrates an exemplary bit stream syntax structure of an MH
RTP payload type descriptor according to an embodiment of the present
invention.
[35] FIG. 20 illustrates an exemplary bit stream syntax structure of an MH
current event descriptor according to an embodiment of the present invention.
[36] FIG. 21 illustrates an exemplary bit stream syntax structure of an MH
next event descriptor according to an embodiment of the present invention.
[37] FIG. 22 illustrates an exemplary bit stream syntax structure of an MH
system time descriptor according to an embodiment of the present invention.
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[38] FIG. 23 illustrates segmentation and encapsulation processes of a
service map table according to an embodiment of the present invention.
[39] FIG. 24 illustrates a flow chart for accessing a virtual channel using
FIC and SMT according to an embodiment of the present invention.
[40] FIG. 25 is a view showing a protocol stack of an MH system
according to one embodiment of the present invention.
[41] FIG. 26 is a block diagram showing the configuration of a digital
broadcast receiver according to one embodiment of the present invention.
[42] FIG. 27 is a view showing another embodiment of a bit stream
syntax of a service map table according to one embodiment of the present
invention.
[43] FIG. 28 is a view showing the syntax of a conditional access
descriptor according to one embodiment of the present invention.
[44] FIG. 29 is a view showing the structure of an RS frame according to
one embodiment of the present invention.
[45] FIG. 30 is a view showing an MH TP format according to one
embodiment of the present invention.
[46] FIG. 31 is a view showing the structure of data encrypted at an IP
level, according to
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one embodiment of the present invention.
[47] FIG. 32 is a view showing the structure of data encrypted at an RTP
level, according
to one embodiment of the present invention.
[48] FIG. 33 is a view showing the structure of data encrypted at a raw
level, according to
one embodiment of the present invention.
[49] FIG. 34 is a view illustrating an AES-CTR mode encryption process
which is
applicable to one embodiment of the present invention.
[50] FIG. 35 is a view illustrating an AES-CTR mode decryption process
which is
applicable to one embodiment of the present invention.
[51] FIG. 36 is a table defining an AES-CTR mode counter value which is
applicable to
one embodiment of the present invention.
[52] FIG. 37 is a view illustrating a process of processing a residue block
in an AES-CTR
mode encryption/decryption process which is applicable to one embodiment of
the
present invention.
[53] FIG. 38 is a detailed view of an SMT including a conditional access
descriptor
according to one embodiment of the present invention.
[54] FIG. 39 is a view showing the structure of an RS frame including an MH
service to
which a conditional access is applied, according to one embodiment of the
present
invention.
[55] FIG. 40 is a flowchart illustrating a control method of a digital
broadcast receiver
according to one embodiment of the present invention.
[56] FIG. 41 is a table defining copy control information (CCI) according
to one
embodiment of the present invention.
[57] FIG. 42 is a view illustrating an encryption mode indicator (EMI)
shown in FIG. 41.
[58] FIG. 43 is a view illustrating an analog protection system (APS) shown
in FIG. 41.
[59] FIG. 44 is a view illustrating a constrained image trigger (CIT) shown
in FIG. 41.
[60] And, FIG. 45 is a flowchart illustrating a control method of a digital
broadcast
receiver and digital broadcast transmitter according to one embodiment of the
present
invention.
Best Mode for Carrying Out the Invention
[61] 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, the same reference numbers will be used throughout the drawings to
refer to
the same or like parts. 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 de-
scription 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 de-
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scription 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.
[62] 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 corresponds to
data
pre-known in accordance with a pre-arranged agreement between the receiving
system
and the transmitting system. Additionally, among the terms used in the present
invention, "MH" corresponds to the initials of "mobile" and "handheld" and
represents
the opposite concept of a fixed-type system. Furthermore, the MH service data
may
include at least one of mobile service data and handheld service data, and
canalso be
referred to as "mobile service data" for simplicity. Herein, the mobile
service data not
only correspond to MH 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 MH service data.
[63] 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. 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
broadcasting real-time transportation information may be transmitted as the mo-
bileservice data.
[64] 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
in-
formation 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. 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
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the mobile service data are multiplexed to the same physical channel and then
transmitted.
[65] Furthermore, the digital broadcast 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. 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.
[66] FIG. 1 illustrates a block diagram showing a structure of a digital
broadcasting
receiving system according to an embodiment of the present invention. The
digital
broadcast receiving system according to the present invention includes a
baseband
processor 100, a management processor 200, and a presentation processor 300.
The
baseband processor 100 includes an operation controller 110, a tuner 120, a de-
modulator 130, an equalizer 140, a known sequence detector (or known data
detector)
150, a block decoder (or mobile handheld block decoder) 160, a primary Reed-
Solomon (RS) frame decoder 170, a secondary RS frame decoder 180, and a
signaling
decoder 190. The operation controller 110 controls the operation of each block
included in the baseband processor 100.
[67] By tuning the receiving system to a specific physical channel
frequency, the tuner
120 enables the receiving system to receive main service data, which
correspond to
broadcast signals for fixed-type broadcast receiving systems, and mobile
service data,
which correspond to broadcast signals for mobile broadcast receiving systems.
At this
point, the tuned frequency of the specific physical channel is down-converted
to an in-
termediate frequency (IF) signal, thereby being outputted to the demodulator
130 and
the known sequence detector 140. The passband digital IF signal being
outputted from
the tuner 120 may only include main service data, or only include mobile
service data,
or include both main service data and mobile service data.
[68] The demodulator 130 performs self-gain control, carrier wave recovery,
and timing
recovery processes on the passband digital IF signal inputted from the tuner
120,
thereby modifying the IF signal to a baseband signal. Then, the demodulator
130
outputs the baseband signal to the equalizer 140 and the known sequence
detector 150.
The demodulator 130 uses the known data symbol sequence inputted from the
known
sequence detector 150 during the timing and/or carrier wave recovery, thereby
enhancing the demodulating performance. The equalizer 140 compensates channel-
associated distortion included in the signal demodulated by the demodulator
130.
Then, the equalizer 140 outputs the distortion-compensated signal to the blcok
decoder
160. By using a known data symbol sequence inputted from the lnown sequence
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detector 150, the equalizer 140 may enhance the equalizing performance.
Furthermore,
the equalizer 140 may receive feed-back on the decoding result from the block
decoder
160, thereby enhancing the equalizing performance.
[69] The known sequence detector 150 detects known data place (or position)
inserted by
the transmitting system from the input/output data (i.e., data prior to being
de-
modulated or data being processed with partial demodulation). Then, the known
sequence detector 150 outputs the detected known data position information and
known data sequence generated from the detected position information to the de-
modulator 130 and the equalizer 140. Additionally, in order to allow the block
decoder
160 to identify the mobile service data that have been processed with
additional
encoding by the transmitting system and the main service data that have not
been
processed with any additional encoding, the known sequence detector 150
outputs such
corresponding information to the block decoder 160.
[70] If the data channel-equalized by the equalizer 140 and inputted to the
block decoder
160 correspond to data processed with both block-encoding and trellis-encoding
by the
transmitting system (i.e., data within the RS frame, signaling data), the
block decoder
160 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
140 and inputted to the block decoder 160 correspond to data processed only
with
trellis-encoding and not block-encoding by the transmitting system (i.e., main
service
data), the block decoder 160 may perform only trellis-decoding.
[71] The signaling decoder 190 decodes signaling data that have been
channel-equalized
and inputted from the equalizer 140. It is assumed that the signaling data
inputted to
the signaling decoder 190 correspond to data processed with both block-
encoding and
trellis-encoding by the transmitting system. Examples of such signaling data
may
include transmission parameter channel (TPC) data and fast information channel
(FIC)
data. Each type of data will be described in more detail in a later process.
The FIC data
decoded by the signaling decoder 190 are outputted to the FIC handler 215.
And, the
TPC data decoded by the signlaing decoder 190 are outputted to the TPC handler
214.
[72] 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 secodnary RS frame will be
divided
based upon the level of importance of the corresponding data. The primary RS
frame
decoder 170 receives the data outputted from the block decoder 160. At this
point,
according to the embodiment of the present invention, the primary RS frame
decoder
170 receives only the mobile service data that have been Reed-Solomon (RS)-
encoded
and/or cyclic reduncancy check (CRC)-encoded from the block decoder 160.
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[73] Herein, the primary RS frame decoder 170 receives only the mobile
service data and
not the main service data. The primary RS frame decoder 170 performs inverse
processes of an RS frame encoder (not shown) included in the digital broadcast
transmitting system, thereby correcting errors existing within the primary RS
frame.
More specifically, the primary RS frame decoder 170 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 170 decodes primary RS frames,
which
are being transmitted for actual broadcast services.
[74] Additionally, the secondary RS frame decoder 180 receives the data
outputted from
the block decoder 160. At this point, according to the embodiment of the
present
invention, the secondary RS frame decoder 180 receives only the mobile service
data
that have been RS-encoded and/or CRC-encoded from the block decoder 160.
Herein,
the secondary RS frame decoder 180 receives only the mobile service data and
not the
main service data. The secondary RS frame decoder 180 performs inverse
processes of
an RS frame encoder (not shown) included in the digital broadcast transmitting
system,
thereby correcting errors existing within the secondary RS frame. More
specifically,
the secondary RS frame decoder 180 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 180 decodes secondary RS frames, which
are
being transmitted for mobile audio service data, mobile video service data,
guide data,
and so on.
[75] Meanwhile, the management processor 200 according to an embodiment of
the
present invention includes an MH physical adaptation processor 210, an IP
network
stack 220, a streaming handler 230, a system information (SI) handler 240, a
file
handler 250, a multi-purpose internet main extensions (MIME) type handler 260,
and
an electronic service guide (ESG) handler 270, and an ESG decoder 280, and a
storage
unit 290. The MH physical adaptation processor 210 includes a primary RS frame
handler 211, a secondary RS frame handler 212, an MH transport packet (TP)
handler
213, a TPC handler 214, an FIC handler 215, and a physical adpatation control
signal
handler 216. The TPC handler 214 receives and processes baseband information
required by modules corresponding to the MH physical adaptation processor 210.
The
baseband information is inputted in the form of TPC data. Herein, the TPC
handler 214
uses this information to process the FIC data, which have been sent from the
baseband
processor 100.
[76] The TPC data istransmitted from the transmitting system to the
receiving system via
a predetermined region of a data group. The TPC data may include at least one
of an
MH ensemble ID, an MH sub-frame number, a total number of MH groups (TNoG), an
RS frame continuity counter, a column size of RS frame (N), and an FIC version
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number. Herein, the MH ensemble ID indicates an identification number of each
MH
ensemble carried in the corresponding physical channel. The MH sub-frame
number
signifies a number identifying the MH sub-frame number in oneMH frame, wherein
each MH group associated with the corresponding MH ensemble is transmitted.
The
TNoG represents the total number of MH groups including all of the MH groups
belonging to all MH parades included in oneMH sub-frame. The RS frame
continuity
counter indicates a number that serves as a continuity indicatorof the RS
frames
carrying the corresponding MH ensemble. Herein, the value of the RS frame
continuity
counter shall be incremented by 1 modulo 16 for each successive RS frame. N
represents the column size of an RS frame belonging to the corresponding MH
ensemble. Herein, the value of N determines the size of each MH TP. Finally,
the FIC
version number signifies the version number of an FIC body carried on the cor-
responding physical channel.
[77] As described above, diverse TPC data are inputted to the TPC handler
214 via the
signaling decoedr 190 shown in FIG. 1. Then, the received TPC data are
processed by
the TPC handler 214. The received TPC data may also be used by the FIC handler
215
in order to process the FIC data. The FIC handler 215 processes the FIC data
by as-
sociating the FIC data received from the baseband processor 100 with the TPC
data.
The physical adaptation control signal handler 216 collects FIC data received
through
the FIC handler 215 and SI data received through RS frames. Then, the physical
adaptation control signal handler 216 uses the collected FIC data and SI data
to
configure and process IP datagrams and access information of mobile broadcast
services. Thereafter, the physical adaptation control signal handler 216
stores the
processed IP datagrams and access information to the storage unit 290.
[78] The primary RS frame handler 211 identifies primary RS frames received
from the
primary RS frame decoder 170 of the baseband processor 100 for each row unit,
so as
to configure an MH TP. Thereafter, the primary RS frame handler 211 outputs
the
configured MH TP to the MH TP handler 213. The secondary RS frame handler 212
identifies secondary RS frames received from the secondary RS frame decoder
180 of
the baseband processor 100 for each row unit, so as to configure an MH TP.
Thereafter, the secondary RS frame handler 212 outputs the configured MH TP to
the
MH TP handler 213. The MH transport packet (TP) handler 213 extracts a header
from
each MH TP received from the primary RS frame handler 211 and the secondary RS
frame handler 212, thereby determining the data included in the corresponding
MH TP.
Then, when the determined data correspond to SI data (i.e., SI data that are
not en-
capsulated to IP datagrams), the corresponding data are outputted to the
physical
adaptation control signal handler 216. Alterantively, when the determined data
correspond to an IP datagram, the corresponding data are outputted to the IP
network
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stack 220.
[79] The IP network stack 220 processes broadcast data that are being
transmitted in the
form of IP datagrams. More specifically, the IP network stack 220 processes
data that
are inputted via user datagram protocol (UDP), real-time transport protocol
(RTP),
real-time transport control protocol (RTCP), asynchronous layered
coding/layered
coding transport (ALC/LCT), file delivery over unidirectional transport
(FLUTE), and
so on. Herein, when the processed data correspond to streaming data, the cor-
responding data are outputted to the streaming handler 230. And, when the
processed
data correspond to data in a file format, the corresponding data are outputted
to the file
handler 250. Finally, when the processed data correspond to SI-associated
data, the
corresponding data are outputted to the SI handler 240.
[80] The SI handler 240 receives and processes SI data having the form of
IP datagrams,
which are inputted to the IP network stack 220. When the inputted data
associated with
SI correspond to MIME-type data, the inputted data are outputted to the MIME-
type
handler 260. The MIME-type handler 260 receives the MIME-type SI data
outputted
from the SI handler 240 and processes the received MIME-type SI data. The file
handler 250 receives data from the IP network stack 220 in an object format in
accordance with the ALC/LCT and FLUTE structures. The file handler 250 groups
the
received data to create a file format. Herein, when the corresponding file
includes
ESG(Electronic Service Guide), the file is outputted to the ESG handler 270.
On the
other hand, when the corresponding file includes data for other file-based
services, the
file is outputted to the presentation controller 330 of the presentation
processor 300.
[81] The ESG handler 270 processes the ESG data received from the file
handler 250 and
stores the processed ESG data to the storage unit 290. Alternatively, the ESG
handler
270 may output the processed ESG data to the ESG decoder 280, thereby allowing
the
ESG data to be used by the ESG decoder 280. The storage unit 290 stores the
system
information (SI) received from the physical adaptation control signal handler
210 and
the ESG handler 270 therein. Thereafter, the storage unit 290 transmits the
stored SI
data to each block.
[82] The ESG decoder 280 either recovers the ESG data and SI data stored in
the storage
unit 290 or recovers the ESG data transmitted from the ESG handler 270. Then,
the
ESG decoder 280 outputs the recovered data to the presentation controller 330
in a
format that can be outputted to the user. The streaming handler 230 receives
data from
the IP network stack 220, wherein the format of the received data are in
accordance
with RTP and/or RTCP structures. The streaming handler 230 extracts
audio/video
streams from the received data, which are then outputted to the audio/video
(AN)
decoder 310 of the presentation processor 300. The audio/video decoder 310
then
decodes each of the audio stream and video stream received from the streaming
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handler 230.
[83] The display module 320 of the presentation processor 300 receives
audio and video
signals respectively decoded by the A/V decoder 310. Then, the display module
320
provides the received audio and video signals to the user through a speaker
and/or a
screen. The presentation controller 330 corresponds to a controller managing
modules
that output data received by the receiving system to the user. The channel
service
manager 340 manages an interface with the user, which enables the user to use
channel-based broadcast services, such as channel map management, channel
service
connection, and so on. The application manager 350 manages an interface with a
user
using ESG display or other application services that do not correspond to
channel-
based services.
[84] Meanwhile, the data structure used in the mobile broadcasting
technology according
to the embodiment of the present invention may include a data group structure
and an
RS frame structure, which will now be described in detail. FIG. 2 illustrates
an
exemplary structure of a data group according to the present invention. FIG. 2
shows
an example of dividing a data group according to the data structure of the
present
invention into 10 MH blocks (i.e., MH block 1 (B1) to MH block 10 (B10)). In
this
example, each MH block has the length of 16 segments. Referring to FIG. 2,
only the
RS parity data are allocated to portions of the first 5 segments of the MH
block 1 (B1)
and the last 5 segments of the MH block 10 (B10). The RS parity data are
excluded in
regions A to D of the data group. More specifically, when it is assumed that
one data
group is divided into regions A, B, C, and D, each MH block may be included in
any
one of region A to region D depending upon the characteristic of each MH block
within the data group(For example, the characteristic of each MH block can be
an in-
terference level of main service data).
[85] 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. Ad-
ditionally, 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
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.
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[86] Referring to FIG. 2, MH block 4 (B4) to MH block 7 (B7) correspond to
regions
without interference of the main service data. MH block 4 (B4) to MH block 7
(B7)
within the data group shown in FIG. 2 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 MH block. In the description of
the
present invention, the region including MH block 4 (B4) to MH 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 MH block, the receiving system is capable of performing
equalization
by using the channel information that can be obtained from the known data.
Therefore,
region A may have the strongest equalizing performance among region A, B, C
and D..
[87] In the example of the data group shown in FIG. 2, MH block 3 (B3) and
MH block 8
(B8) correspond to a region having little interference from the main service
data.
Herein, a long known data sequence is inserted in only one side of each MH
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 MH block 3 (B3), and another
long
known data sequence is inserted at the beginning of MH block 8 (B8). In the
present
invention, the region including MH block 3 (B3) and MH block 8 (B8) will be
referred
to as "region B (=B3+B8)". 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 MH 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) in region B.
[88] Referring to FIG. 2, MH block 2 (B2) and MH 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 MH block 2 (B2) and MH
block
9 (B9). Herein, the region including MH block 2 (B2) and MH block 9 (B9) will
be
referred to as "region C (=B2+B9)". Finally, in the example shown in FIG. 2,
MH
block 1 (B1) and MH block 10 (B10) correspond to a region having more
interference
from the main service data as compared to region C. Similarly, a long known
data
sequence cannot be inserted in any side of MH block 1 (B1) and MH block 10
(B10).
Herein, the region including MH block 1 (B1) and MH 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.
[89] Additionally, the data group includes a signaling information area
wherein signaling
information is assigned (or allocated). In the present invention, the
signaling in-
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formation area may start from the 1st segment of the 4th MH block (B4) to a
portion of
the 2nd segment. According to an embodiment of the present invention, the
signaling
information area for inserting signaling information may start from the 1st
segment of
the 4th MH block (B4) to a portion of the 2nd segment. More specifically,
276(=207+69) bytes of the 4th MH 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 MH
block (B4). The 1st segment of the 4th MH block (B4) corresponds to the 17th
or
173rd segment of a VSB field.
[90] 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). Herein, the TPC data may include at least one of an MH ensemble
ID,
an MH sub-frame number, a total number of MH groups (TNoG), an RS frame
continuity counter, a column size of RS frame (N), and an FIC version number.
However, the TPC data (or information) presented herein are merely exemplary.
And,
since the adding or deleting of signaling information included in the TPC data
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. Furthermore, the
FIC is
provided to enable a fast service acquisition of data receivers, and the FIC
includes
cross layer information between the physical layer and the upper layer(s).
[91] For example, when the data group includes 6 known data sequences, as
shown in
FIG. 2, the signaling information area is located between the first known data
sequence
and the second known data sequence. More specifically, the first known data
sequence
is inserted in the last 2 segments of the 3rd MH block (B3), and the second
known data
sequence isinserted in the 2nd and 3rd segments of the 4th MH 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 MH blocks (B4, B5, B6, and B7).
The 1st
and 3rd to 6th known data sequences are spaced apart by 16 segments.
[92] FIG. 3 illustrates an RS frame according to an embodiment of the
present invention.
The RS frame shown in FIG. 3 corresponds to a collection of one or more data
groups.
The RS frame is received for each MH frame in a condition where the receiving
system receives the FIC and processes the received FIC and where the receiving
system is switched to a time-slicing mode so that the receiving system can
receive MH
ensembles including ESG entry points. Each RS frame includes each service or
IP
streams of ESG, and SMT section data may exist in all RS frames. The RS frame
according to the embodiment of the present invention consists of at least one
MH
transport packet (TP). Herein, the MH TP includes an MH header and an MH
payload.
[93] The MH payload may include mobile service data as wekk as signaling
data. More
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specifically, an MH payload may include only mobile service data, or may
include
only signaling data, or may include both mobile service data and signaling
data.
According to the embodiment of the present invention, the MH header may
identify (or
distinguish) the data types included in the MH payload. More specifically,
when the
MH TP includes a first MH header, this indicates that the MH payload includes
only
the signaling data. Also, when the MH TP includes a second MH header, this
indicates
that the MH payload includes both the signaling data and the mobile service
data.
Finally, when MH TP includes a third MH header, this indicates that the MH
payload
includes only the mobile service data. In the example shown in FIG. 3, the RS
frame is
assigned with IP datagrams (for example, IP datagram 1 and IP datagram 2) for
two
service types.
[94] FIG. 4 illustrates a structure of a MH frame for transmitting and
receiving mobile
service data according to the present invention. In the example shown in FIG.
4, one
MH frame consists of 5 sub-frames, wherein each sub-frame includes 16 slots.
In this
case, the MH frame according to the present invention includes 5 sub-frames
and 80
slots. 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
onedata
segment, a data packet prior to being interleaved may also be used as a data
segment.
At this point, two VSB fields are grouped to form a VSB frame.
[95] FIG. 5 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. The slot
corresponds
to a basic time unit 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. If the first 118 data packets within the slot correspond to
a data
group, the remaining 38 data packets become the main service data packets. In
another
example, when no data group exists in a slot, the corresponding slot is
configured of
156 main service data packets. Meanwhile, when the slots are assigned to a VSB
frame, an off-set exists for each assigned position.
[96] FIG. 6 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 spatial area. And,
FIG. 7 il-
lustrates 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 chronological (or time) area.
Referring
to FIG. 6 and FIG. 7, 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
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38th data packet (TS packet #37) of a 3rd 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.
[97] FIG. 8 illustrates an exemplary assignement order of data groups being
assigned to
one of 5 sub-frames, wherein the 5 sub-frames configure an MH frame. For
example,
the method of assigning data groups may be identically applied to all MH
frames or
differently applied to each MH frame. Furthermore, the method of assinging
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 MH frame, the total number
of
data groups being assigned to an MH frame is equal to a multiple of '5'.
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 sub-
frame.
Thus, the system can be capable of responding promptly and effectively to any
burst
error that may occur within a sub-frame.
[98] 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. 8 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. Equation 1
below shows
the above-described rule (or pattern) for assigning data groups in a sub-
frame.
[99]
[100] Equation 1
[101]
[102] j = (4i + 0) mod 16
[103]
[104] Herein, O= 0 if i < 4,
[105] 0 = 2 else if i < 8,
[106] 0 = 1 else if i < 12,
[107] 0 = 3 else.
[108]
[109] Herein, j indicates the slot number within a sub-frame. The value of
j may range from
0 to 15. Also, variable i indicates the data group number. The value of i may
range
from 0 to 15.
[110] In the present invneiton, a collection of data groups included in a
MH frame will be
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referred to as a "parade". Based upon the RS frame mode, the parade transmits
data of
at least one specific RS frame. 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.
[111] According to the embodiment 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. 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. More specifically, the RS frame mode indicates whether a parade
transmits
one RS frame, or whether the parade transmits two RS frames. Such RS frame
mode is
transmitted as the above-described TPC data. Table 1 below shows an example of
the
RS frame mode.
[112]
[113] Table 1
[Table 1]
[Table 1
RS frame mode Description
00 There is only a primary RS frame for all Group
Regions
01 There are two separate RS frames- Primary RS frame
for
Group Region A and B- Secondary RS frame for Group
Region C and D
Reserved
11 Reserved
[114]
[115] 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
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'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.
Similarly,
data of the secondary RS frame for regions C/D are assigned and transmitted to
regions
C/D of the corresponding data group.
[116] 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. Furthermore, the method of assigning parades may be
identically applied to all MH frames or differently applied to each MH frame.
According to the embodiment of the present invention, the parades may be
assigned
differently for each sub-frame and identically for all sub-frames within an MH
frame.
However, according to the embodiment of the present invention, the parades may
be
assigned differently for each MH frame and identically for all sub-frames
within an
MH frame. More specifically, the MH frame structure may vary by MH frame
units.
Thus, an ensemble rate may be adjusted on a more frequent and flexible basis.
[117] FIG. 9 illustrates an example of multiple data groups of a single
parade being
assigned (or allocated) to an MH frame. More specifically, FIG. 9 illustrates
an
example of a single parade, wherein the number of data groups included in a
sub-frame
is equal to '3', being allocated to an MH frame. Referring to FIG. 9, 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
MH frame, 15 data groups are assigned to a single MH 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.
[118] For example, when it is assumed that one parade transmits one RS
frame, and that a
RS frame encoder (not shown) included in the transmitting system performs RS-
encoding on the corresponding RS frame, thereby adding 24 bytes of parity data
to the
corresponding RS frame and transmitting the processed RS frame, the parity
data
occupy approximately 11.37% (=24/(187+24)x100) of the total RS 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. 9, 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
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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 and
bytes error
among one RS code word that is less than the number of RS parity bytes may be
corrected. By doing so, the 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.
[119] Meanwhile, when data groups of a parade are assigned as shown in FIG.
9, either
main service data may be assigned between each data group, or data groups cor-
responding to different parades may be assigned between each data group. More
specifically, data groups corresponding to multiple parades may be assigned to
one
MH frame. Basically, the method of assigning data groups corresponding to
multiple
parades is 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 MH frame are also respectively assigned 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. 9, data groups corresponding to the next parade
may be
assigned to a sub-frame starting either from the 12th slot of a sub-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.
[120] FIG. 10 illustrates an example of transmitting 3 parades (Parade #0,
Parade #1, and
Parade #2) viaan MH frame. More specifically, FIG. 10 illustrates an example
of
transmitting parades included in one of 5 sub-frames, wherein the 5 sub-frames
configure one MH frame. 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. More specifically, the data groups of the 2nd parade (Parade #1)
are se-
quentially assigned to the 2nd and 12th slots (Slot #1 and Slot #11) within
the sub-
frame. 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
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values '5' and '6' for i in Equation 1. More specifically, the data groups of
the 3rd
parade (Parade #2) are sequentially assigned to the 7th and 1 lth slots (Slot
#6 and Slot
#10) within the sub-frame.
[121] As described above, data groups of multiple parades may be assigned
to a single MH
frame, and, in each sub-frame, the data groups are serially allocated to a
group space
having 4 slots from left to right. 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 MH
frame includes 5 sub-frames, the total number of data groups within a parade
that can
be allocated to an MH frame may correspond to any one multiple of '5' ranging
from
'5' to '40'.
[122] FIG. 11 illustrates an example of expanding the assignment process of
3 parades,
shown in FIG. 10, to 5 sub-frames within an MH frame. FIG. 12 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. As
described above,
an MH 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 MH fram units, thereby configuring a single parade.
[123] The data structure shown in FIG. 12 includes 3 parades, one ESG
dedicated channel
(EDC) parade (i.e., parade with NoG=1), and 2 service parades (i.e., parade
with
NoG=4 and parade with NoG=3). 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. Herein, each FIC segment is interleaved by MH sub-frame
units,
thereby configuring an FIC body, which corresponds to a completed FIC
transmission
structure. However, whenever required, each FIC segment may be interleaved by
MH
frame units and not by MH sub-frame units, thereby being completed in MH frame
units.
[124] Meanwhile, the concept of an MH ensemble is applied in the embodiment
of the
present invention, thereby defining a collection (or group) of services. Each
MH
ensemble carries the same QoS and is coded with the same FEC code. Also, each
MH
ensemble has the same unique identifier (i.e., ensemble ID) and corresponds to
consecutive RS frames. As shown in FIG. 12, the FIC segment corresponding to
each
data group may describe service information of an MH ensemble to which the cor-
responding data group belongs. When FIC segments within a sub-frame are
grouped
and deinterleved, all service information of a physical channel through which
the cor-
responding FICs are transmitted may be obtained. Therefore, the receiving
system may
be able to acquire the channel information of the corresponding physical
channel, after
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being processed with physical channel tuning, during a sub-frame period.
Furthermore,
FIG. 12 illustrates a structure further including a separate EDC parade apart
from the
service parade and wherein electronic service guide (ESG) data are transmitted
in the
1st slot of each sub-frame.
[1251 FIG. 13 illustrates a hierarchical signaling structure according to
an embodiment of
the present invention. As shown in FIG. 13, the mobile broadcasting
techonology
according to the embodiment of the present invention adopts a signaling method
using
FIC and SMT. In the description of the present invention, the signaling
structure will
be referred to as a hierarchical signaling structure. Hereinafter, a detailed
description
on how the receiving system accesses a virtual channel via FIC and SMT will
now be
given with reference to FIG. 13. The FIC body defined in an MH transport (M1)
identifies the physical location of each the data stream for each virtual
channel and
provides very high level descriptions of each virtual channel. Being MH
ensemble
level signaling information, the service map table (SMT) provides MH ensemble
level
signaling information. The SMT provides the IP access information of each
virtual
channel belonging to the respective MH ensemble within which the SMT is
carried.
The SMT also provides all IP stream component level information required for
the
virtual channel service acquisition.
[1261 Referring to FIG. 13, each MH ensemble (i.e., Ensemble 0, Ensemble 1,
...,
Ensemble K) includes a stream information on each associated (or
corresponding)
virtual channel (e.g., virtual channel 0 IP stream, virtual channel 1 IP
stream, and
virtual channel 2 IP stream). For example, Ensemble 0 includes virtual channel
0 IP
stream and virtual channel 1 IP stream. And, each MH ensemble includes diverse
in-
formation on the associated virtual channel (i.e., Virtual Channel 0 Table
Entry,
Virtual Channel 0 Access Info, Virtual Channel 1 Table Entry, Virtual Channel
1
Access Info, Virtual Channel 2 Table Entry, Virtual Channel 2 Access Info,
Virtual
Channel N Table Entry, Virtual Channel N Access Info, and so on). The FIC body
payload includes information on MH ensembles (e.g., ensemble id field, and
referred
to as "ensemble location" in FIG. 13) and information on a virtual channel
associated
with the corresponding MH ensemble (e.g., major channel num field and
minor channel num field, and referred to as "Virtual Channel 0", "Virtual
Channel 1",
..., "Virtual Channel N" in FIG. 13).
[1271 The application of the signaling structure in the receiving system
will now be
described in detail. When a user selects a channel he or she wishes to view
(hereinafter, the user-selected channel will be referred to as "channel 0" for
simplicity), the receiving system first parses the received FIC. Then, the
receiving
system acquires information on an MH ensemble (i.e., ensemble location), which
is
associated with the virtual channel corresponding to channel 0 (hereinafter,
the cor-
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responding MH ensemble will be referred to as "MH ensemble 0" for simplicity).
By
acquiring slots only corresponding to the MH ensemble 0 using the time-slicing
method, the receiving system configures ensemble 0. The ensemble 0 configured
as
described above, includes an SMT on the associated virtual channels (including
channel 0) and IP streams on the corresponding virtual channels. Therefore,
the
receiving system uses the SMT included in the MH ensemble 0 in order to
acquire
various information on channel 0 (e.g., Virtual Channel 0 Table Entry) and
stream
access information on channel 0 (e.g., Virtual Channel 0 Access Info). The
receiving
system uses the stream access information on channel 0 to receive only the
associated
IP streams, thereby providing channel 0 services to the user.
[128] The digital broadcast receiving system according to the present
invention adopts the
fast information channel (FIC) for a faster access to a service that is
currently being
broadcasted. More specifically, the FIC handler 215 of FIG. 1 parses the FIC
body,
which corresponds to an FIC transmission structure, and outputs the parsed
result to
the physical adaptation control signal handler 216. FIG. 14 illustrates an
exemplary
FIC body format according to an embodiment of the present invention. According
to
the embodiment of the present invention, the FIC format consists of an FIC
body
header and an FIC body payload.
[129] Meanwhile, according to the embodiment of the present invention, data
are
transmitted through the FIC body header and the FIC body payload in FIC
segment
units. Each FIC segment has the size of 37 bytes, and each FIC segment
consists of a
2-byte FIC segment header and a 35-byte FIC segment payload. More
specifically, an
FIC body configured of an FIC body header and an FIC body payload, is
segmented in
units of 35 bytes, which are then carried in FIC segment payload within at
least one of
FIC segment, so as to be transmitted. In the description of the present
invention, an
example of inserting one FIC segment in one data group, which is then
transmitted,
will be given. In this case, the receiving system receives a slot
corresponding to each
data group by using a time-slicing method.
[130] The signaling decoder 190 included in the receiving system shown in
FIG. 1 collects
each FIC segment inserted in each data group. Then, the signaling decoder 190
uses
the collected FIC segments to created a single FIC body. Thereafter, the
signaling
decoder 190 performs a decoding process on the FIC body payload of the created
FIC
body, so that the decoded FIC body payload corresponds to an encoded result of
a
signaling encoder (not shown) included in the transmitting system.
Subsequently, the
decoded FIC body payload is outputted to the FIC handler 215. The FIC handler
215
parses the FIC data included in the FIC body payload, and then outputs the
parsed FIC
data to the physical adaptation control signal handler 216. The physical
adaptation
control signal handler 216 uses the inputted FIC data to perform processes
associated
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with MH ensembles, virtual channels, SMTs, and so on.
[131] According to an embodiment of the present invention, when an FIC body
is
segmented, and when the size of the last segmented portion is smaller than 35
data
bytes, it is assumed that the lacking number of data bytes in the FIC segment
payload
is completed with by adding the same number of stuffing bytes therein, so that
the size
of the last FIC segment can be equal to 35 data bytes. However, it is apparent
that the
above-described data byte values (i.e., 37 bytes for the FIC segment, 2 bytes
for the
FIC segment header, and 35 bytes for the FIC segment payload) are merely
exemplary,
and will, therefore, not limit the scope of the present invention.
[132] FIG. 15 illustrates an exemplary bit stream syntax structure with
respect to an FIC
segment according to an embodiment of the present invention. Herein, the FIC
segment signifies a unit used for transmitting the FIC data. The FIC segment
consists
of an FIC segment header and an FIC segment payload. Referring to FIG. 15, the
FIC
segment payload corresponds to the portion starting from the 'for' loop
statement.
Meanwhile, the FIC segment header may include a FIC type field, an error
indicator
field, an FIC seg number field, and an FIC last seg number field. A detailed
de-
scription of each field will now be given.
[133] The FIC type field is a 2-bit field indicating the type of the
corresponding FIC. The
error indicator field is a 1-bit field, which indicates whether or not an
error has
occurred within the FIC segment during data transmission. If an error has
occurred, the
value of the error indicator field is set to '1'. More specifically, when an
error that has
failed to be recovered still remains during the configuration process of the
FIC
segment, the error indicator field value is set to '1'. The error indicator
field enables
the receiving system to recognize the presence of an error within the FIC
data. The
FIC seg number field is a 4-bit field. Herein, when a single FIC body is
divided into a
plurality of FIC segments and transmitted, the FIC seg number field indicates
the
number of the corresponding FIC segment. Finally, the FIC last seg number
field is
also a 4-bit field. The FIC last seg number field indicates the number of the
last FIC
segment within the corresponding FIC body.
[134] FIG. 16 illustrates an exemplary bit stream syntax structure with
respect to a payload
of an FIC segment according to the present invention, when an FIC type field
value is
equal to '0'. According to the embodiment of the present invention, the
payload of the
FIC segment is divided into 3 different regions. A first region of the FIC
segment
payload exists only when the FIC seg number field value is equal to '0'.
Herein, the
first region may include a current next indicator field, an ESG version field,
and a
transport stream id field. However, depending upon the embodiment of the
present
invention, it may be assumed that each of the 3 fields exists regardless of
the
FIC seg number field.
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[1351 The current next indicator field is a 1-bit field. The current next
indicator field acts
as an indicator identifying whether the corresponding FIC data carry MH
ensemble
configuration information of an MH frame including the current FIC segment, or
whether the corresponding FIC data carry MH ensemble configuration information
of a
next MH frame. The ESG version field is a 5-bit field indicating ESG version
in-
formation. Herein, by providing version information on the service guide
providing
channel of the corresponding ESG, the ESG version field enables the receiving
system
to notify whether or not the corresponding ESG has been updated. Finally, the
transport stream id field is a 16-bit field acting as a unique identifier of a
broadcast
stream through which the corresponding FIC segment is being transmitted.
[1361 A second region of the FIC segment payload corresponds to an ensemble
loop
region, which includes an ensemble id field, an SI version field, and a num
channel
field. More specifically, the ensemble id field is an 8-bit field indicating
identifiers of
an MH ensemble through which MH services are transmitted. Herein, the ensemble
id
field binds the MH services and the MH ensemble. The SI version field is a 4-
bit field
indicating version information of SI data included in the corresponding
ensemble,
which is being transmitted within the RS frame. Finally, the num channel field
is an
8-bit field indicating the number of virtual channel being transmitted via the
cor-
responding ensemble.
[1371 A third region of the FIC segment payload a channel loop region,
which includes a
channel type field, a channel activity field, a CA indicator field, a
stand alone service indicator field, a major channel num field, and a
minor channel num field. The channel type field is a 5-bit field indicating a
service
type of the corresponding virtual channel. For example, the channel type field
may
indicates an audio/video channel, an audio/video and data channel, an audio-
only
channel, a data-only channel, a file download channel, an ESG delivery
channel, a no-
tification channel, and so on. The channel activity field is a 2-bit field
indicating
activity information of the corresponding virtual channel. More specifically,
the
channel activity field may indicate whether the current virtual channel is
providing the
current service.
[1381 The CA indicator field is a 1-bit field indicating whether or not a
conditional access
(CA) is applied to the current virtual channel. The stand alone service
indicator field
is also a 1-bit field, which indicates whether the service of the
corresponding virtual
channel corresponds to a stand alone service. The major channel num field is
an 8-bit
field indicating a major channel number of the corresponding virtual channel.
Finally,
the minor channel num field is also an 8-bit field indicating a minor channel
number
of the corresponding virtual channel.
[1391 FIG. 17 illustrates an exemplary bit stream syntax structure of a
service map table
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= 74420-439
25==
(hereinafter referred to as "SMT") according to the present invention.
According to a non-
limiting embodiment of the present invention, the SMT is configured in an MPEG-
2 private
section format. The SMT according to the embodiment of the present invention
includes
description information for each virtual channel within a single MH ensemble.
And,
additional information may further be included in each descriptor area.
Herein, the
SMT according to the embodiment of the present invention includes at least one
field
= and is transmitted from the transmitting system to the receiving system.
[140] As described in FIG. 3, the SMT section may be transmitted
by being included in the
= MH TP within the RS frame. In this case, each of the RS frame decoders
170 and 180,
=
shown in FIG. 1, decodes the inputted RS frame, respectively. Then, each of
the
= decoded RS frames is outputted to the respective RS frame handler 211 and
212.
Thereafter, each RS frame handler 211 and 212 identifies the inputted RS frame
by
row units, so as to create an MH TP, thereby outputting the created MH TP to
the MH
TP handler 213. When it is determined that the corresponding MH TP includeS an
SMT section based upon the header in each of the inputted MH TP, the MH TP
handler 213 parses the corresponding SMT section, so as to output the SI data
within
the parsed SMT section to the physical adaptation control signal handler 216.
However, this is limited to when the SMT is not encapsulated to IP datagrams.
= [141] . Meanwhile, when the SMT is encapsulated to IP datagram, and when
it is = =
determined that the corresponding MH TP includes an SMT section based upon the
= header in each of the inputted MH TP, the MH TP handler 213 outputs the
SMT
section to the IP network stack 220. Accordingly, the IP network stack 220
performs IP
= and UDP processes on the inputted SMT section and, then, outputs the
processed SMT
section to the SI handler 240. The SI handler 240 parses the inputted SMT
section =and
= ==controls the system so that the parsed SI data can be stroed in the
storage unit 290. The
following corresponds to example of the fields that may be transmitted through
the
SMT. =
[142] = The table_id field corresponds to an 8-bit unsigned integer
number, which indicates
the type of table section ,being defined in the service map table(SMT). The =
ensemble_id field is an 8-bit unsigned integer field, which corresponds to an
ID value
associated to the corresponding MH ensemble. Herein, the ensemble_id field may
be =
= assigned with a value ranging from range '0x00' to '0x3F'. It is
preferable that the
= value of the ensemble_id field is derived from the parade_id of the TPC
data, which is
carried from the baseband processor of MH physical layer subsystem. When the
cor-
=
responding MH ensemble is transmitted through (or carried over) the primary RS
= frame, a value of '0' may be used for the most significant bit (MSB), and
the
remaining 7 bits are used as the parade_id value of the associated MH parade
(i.e., for =
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WO 2009/038437 PCT/KR2008/005634
the least significant 7 bits). Alternatively, when the corresponding MH
ensemble is
transmitted through (or carried over) the secondary RS frame, a value of '1'
may be
used for the most significant bit (MSB).
[143] The num channels field is an 8-bit field, which specifies the number
of virtual
channels in the corresponding SMT section. Meanwhile, the SMT according to the
em-
bodimentof the present invention provides information on a plurality of
virtual
channels using the 'for' loop statement. The major channel num field
corresponds to
an 8-bit field, which represents the major channel number associated with the
cor-
responding virtual channel. Herein, the major channel num field may be
assigned
with a value ranging from '0x00' to 'OxFF'. The minor channel num field
corresponds to an 8-bit field, which represents the minor channel number
associated
with the corresponding virtual channel. Herein, the minor channel num field
may be
assigned with a value ranging from '0x00' to 'OxFF'.
[144] The short channel name field indicates the short name of the virtual
channel. The
service id field is a 16-bit unsigned integer number (or value), which
identifies the
virtual channel service. The service type field is a 6-bit enumerated type
field, which
identifiesthe type of service carried in the corresponding virtual channel as
defined in
Table 2 below.
[145]
[146] Table 2
[Table 2]
[Table 1
Ox00 [Reserved]
Ox01 MH digital television - The virtual channel carries television
programming
(audio, video and optional associated data) conforming to ATSC standards.
0x02 MH audio - The virtual channel carries audio programming (audio service
and optional associated data) conforming to ATSC standards.
0x03 MH data only service - The virtual channel carries a data service
conforming to ATSC standards, but no video or audio component.
0x04- [Reserved for future ATSC use]
OxFF
[147]
[148] The virtual channel activity field is a 2-bit enumerated field
identifying the activity
status of the corresponding virtual channel. When the most significant bit
(MSB) of the
virtual channel activity field is '1', the virtual channel is active, and when
the most
significant bit (MSB) of the virtual channel activity field is '0', the
virtual channel is
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inactive. Also, when the least significant bit (LSB) of the virtual channel
activity field
is '1', the virtual channel is hidden (when set to 1), and when the least
significant bit
(LSB) of the virtual channel activity field is '0', the virtual channel is not
hidden. The
num components field is a 5-bit field, which specifies the number of IP stream
components in the corresponding virtual channel. The IP version flag field
corresponds to a 1-bit indicator. More specifically, when the value of the
IP version flag field is set to '1', this indicates that a source IP address
field, a
virtual channel target IP address field, and a component target IP address
field are
IPv6 addresses. Alternatively, when the value of the IP version flag field is
set to '0',
this indicates that the source IP address field, the virtual channel target IP
address
field, and the component target IP address field are IPv4 addresses.
[1491 The source IP address flag field is a 1-bit Boolean flag, which
indicates, when set,
that a source IP address of the corresponding virtual channel exist for a
specific
multicast source. The virtual channel target IP address flag field is a 1-bit
Boolean
flag, which indicates, when set, that the corresponding IP stream component is
delivered through IP datagrams with target IP addresses different from the
virtual channel target IP address. Therefore, when the flag is set, the
receiving
system (or receiver) uses the component target IP address as the target IP
address in
order to access the corresponding IP stream component. Accordingly, the
receiving
system (or receiver) may ignore the virtual channel target IP address field
included
in the num channels loop.
[150] The source IP address field corresponds to a 32-bit or 128-bit field.
Herein, the
source IP address field will be significant (or present), when the value of
the
source IP address flag field is set to '1'. However, when the value of the
source IP address flag field is set to '0', the source IP address field will
become in-
significant (or absent). More specifically, when the source IP address flag
field value
is set to '1', and when the IP version flag field value is set to '0', the
source IP address field indicates a 32-bit IPv4 address, which shows the
source of the
corresponding virtual channel. Alternatively, when the IP version flag field
value is
set to '1', the source IP address field indicates a 128-bit IPv6 address,
which shows
the source of the corresponding virtual channel.
[1511 The virtual channel target IP address field also corresponds to a 32-
bit or 128-bit
field. Herein, the virtual channel target IP address field will be significant
(or
present), when the value of the virtual channel target IP address flag field
is set to
'1'. However, when the value of the virtual channel target IP address flag
field is set
to '0', the virtual channel target IP address field will become insignificant
(or
absent). More specifically, when the virtual channel target IP address flag
field
value is set to '1', and when the IP version flag field value is set to '0',
the
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virtual channel target IP address field indicates a 32-bit target IPv4 address
associated to the corresponding virtual channel. Alternatively, when the
virtual channel target IP address flag field value is set to '1', and when the
IP version flag field value is set to '1', the virtual channel target IP
address field
indicates a 64-bit target IPv6 address associated to the corresponding virtual
channel.
If the virtual channel target IP address field is insignificant (or absent),
the
component target IP address field within the num channels loop should become
significant (or present). And, in order to enable the receiving system to
access the IP
stream component, the component target IP address field should be used.
[152] Meanwhile, the SMT according to the embodiment of the present
invention uses a
'for' loop statement in order to provide information on a plurality of
components.
Herein, the RTP payload type field, which is assigned with 7 bits, identifies
the
encoding format of the component based upon Table 3 shown below. When the IP
stream component is not encapsulated to RTP, the RTP payload type field shall
be
ignored (or deprecated). Table 3 below shows an example of an RTP payload
type.
[153]
[154] Table 3
[Table 3]
[Table 1
RTP payload type Meaning
35 AVC video
36 MH audio
37 -72 [Reserved for future ATSC use]
[155]
[156] The component target IP address flag field is a 1-bit Boolean flag,
which indicates,
when set, that the corresponding IP stream component is delivered through IP
datagrams with target IP addresses different from the
virtual channel target IP address. Furthermore, when the
component target IP address flag is set, the receiving system (or receiver)
uses the
component target IP address field as the target IP address to access the
corresponding
IP stream component. Accordingly, the receiving system (or receiver) will
ignore the
virtual channel target IP address field included in the num channels loop. The
component target IP address field corresponds to a 32-bit or 128-bit field.
Herein,
when the value of the IP version flag field is set to '0', the
component target IP address field indicates a 32-bit target IPv4 address
associated to
the corresponding IP stream component. And, when the value of the IP version
flag
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field is set to '1', the component target IP address field indicates a 128-bit
target
IPv6 address associated to the corresponding IP stream component.
[157] The port num count field is a 6-bit field, which indicates the number
of UDP ports
associated with the corresponding IP stream component. A target UDP port
number
value starts from the target UDP port num field value and increases (or is in-
cremented) by 1. For the RTP stream, the target UDP port number should start
from
the target UDP port num field value and shall increase (or be incremented) by
2. This
is to incorporate RTCP streams associated with the RTP streams.
[158] The target UDP port num field is a 16-bit unsigned integer field,
which represents
the target UDP port number for the corresponding IP stream component. When
used
for RTP streams, the value of the target UDP port num field shall correspond
to an
even number. And, the next higher value shall represent the target UDP port
number of
the associated RTCP stream. The component level descriptor() represents zero
or
more descriptors providing additional information on the corresponding IP
stream
component. The virtual channel level descriptor() represents zero or more
descriptors
providing additional information for the corresponding virtual channel. The
ensemble level descriptor() represents zero or more descriptors providing
additional
information for the MH ensemble, which is described by the corresponding SMT.
[159] FIG. 18 illustrates an exemplary bit stream syntax structure of an MH
audio
descriptor according to the present invention. When at least one audio service
is prese
nt as a component of the current event, the MH audio descriptor() shall be
used as a
component level descriptor of the SMT. The MH audio descriptor() may be
capable
of informing the system of the audio language type and stereo mode status. If
there is
no audio service associated with the current event, then it is preferable that
the
MH audio descriptor() is considered to be insignificant (or absent) for the
current
event. Each field shown in the bit stream syntax of FIG. 18 will now be
described in
detail.
[160] The descriptor tag field is an 8-bit unsigned integer having a TBD
value, which
indicates that the corresponding descriptor is the MH audio descriptor(). The
descriptor length field is also an 8-bit unsigned integer, which indicates the
length (in
bytes) of the portion immediately following the descriptor length field up to
the end of
the MH audio descriptor(). The channel configuration field corresponds to an 8-
bit
field indicating the number and configuration of audio channels. The values
ranging
from '1' to '6' respectively indicate the the number and configuration of
audio
channels as given for "Default bit stream index number" in Table 42 of ISO/IEC
13818-7:2006. All other values indicate that the number and configuration of
audio
channels are undefined.
[161] The sample rate code field is a 3-bit field, which indicates the
sample rate of the
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encoded audio data. Herein, the indication may correspond to one specific
sample rate,
or may correspond to a set of values that include the sample rate of the
encoded audio
data as defined in Table A3.3 of ATSC A/52B. The bit rate code field
corresponds to
a 6-bit field. Herein, among the 6 bits, the lower 5 bits indicate a nominal
bit rate.
More specifically, when the most significant bit (MSB) is '0', the
corresponding bit
rate is exact. On the other hand, when the most significant bit (MSB) is '1',
the bit rate
corresponds to an upper limit as defined in Table A3.4 of ATSC A/53B. The
ISO 639 language code field is a 24-bit (i.e., 3-byte) field indicating the
language
used for the audio stream component, in conformance with ISO 639.2/B [x]. When
a
specific language is not present in the corresponding audio stream component,
the
value of each byte will be set to '0x00'.
[162] FIG. 19 illustrates an exemplary bit stream syntax structure of an MH
RTP payload
type descriptor according to the present invention. The
MH RTP payload type descriptor() specifies the RTP payload type. Yet, the
MH RTP payload type descriptor() exists only when the dynamic value of the
RTP payload type field within the num components loop of the SMT is in the
range
of '96' to '127'. The MH RTP payload type descriptor() is used as a
component level descriptor of the SMT. The MH RTP payload type descriptor
translates (or matches) a dynamic RTP payload type field value into (or with)
a
MIME type. Accordingly, the receiving system (or receiver) may collect (or
gather) the
encoding format of the IP stream component, which is encapsulated in RTP. The
fields
included in the MH RTP payload type descriptor() will now be described in
detail.
[163] The descriptor tag field corresponds to an 8-bit unsigned integer
having the value
TBD, which identifies the current descriptor as the MH RTP payload type
descriptor(). The descriptor length field also corresponds to an 8-bit
unsigned integer,
which indicates the length (in bytes) of the portion immediately following the
descriptor length field up to the end of the MH RTP payload type descriptor().
The
RTP payload type field corresponds to a 7-bit field, which identifies the
encoding
format of the IP stream component. Herein, the dynamic value of the
RTP payload type field is in the range of '96' to '127'. The MIME type length
field
specifies the length (in bytes) of the MIME type field. The MIME type field
indicates
the MIME type corresponding to the encoding format of the IP stream component,
which is described by the MH RTP payload type descriptor().
[164] FIG. 20 illustrates an exemplary bit stream syntax structure of an MH
current event
descriptor according to the present invention. The MH current event
descriptor()
shall be used as the virtual channel level descriptor() within the SMT.
Herein, the
MH current event descriptor() provides basic information on the current event
(e.g.,
the start time, duration, and title of the current event, etc.), which is
transmitted via the
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respective virtual channel. The fields included in the MH current event
descriptor()
will now be described in detail.
[165] The descriptor tag field corresponds to an 8-bit unsigned integer
having the value
TBD, which identifies the current descriptor as the MH current event
descriptor().
The descriptor length field also corresponds to an 8-bit unsigned integer,
which
indicates the length (in bytes) of the portion immediately following the
descriptor length field up to the end of the MH current event descriptor().
The
current event start time field corresponds to a 32-bit unsigned integer
quantity. The
current event start time field represents the start time of the current event
and, more
specifically, as the number of GPS seconds since 00:00:00 UTC, January 6,
1980. The
current event duration field corresponds to a 24-bit field. Herein, the
current event duration field indicates the duration of the current event in
hours,
minutes, and seconds (for example, wherein the format is in 6 digits, 4-bit
BCD = 24
bits). The title length field specifies the length (in bytes) of the title
text field. Herein,
the value '0' indicates that there are no titles existing for the
corresponding event. The
title text field indicates the title of the corresponding event in event title
in the format
of a multiple string structure as defined in ATSC A/65C [x].
[166] FIG. 21 illustrates an exemplary bit stream syntax structure of an MH
next event
descriptor according to the present invention. The optional
MH next event descriptor() shall be used as the virtual channel level
descriptor()
within the SMT. Herein, the MH next event descriptor() provides basic
information
on the next event (e.g., the start time, duration, and title of the next
event, etc.), which
is transmitted via the respective virtual channel. The fields included in the
MH next event descriptor() will now be described in detail.
[167] The descriptor tag field corresponds to an 8-bit unsigned integer
having the value
TBD, which identifies the current descriptor as the MH next event
descriptor(). The
descriptor length field also corresponds to an 8-bit unsigned integer, which
indicates
the length (in bytes) of the portion immediately following the descriptor
length field
up to the end of the MH next event descriptor(). The next event start time
field
corresponds to a 32-bit unsigned integer quantity. The next event start time
field
represents the start time of the next event and, more specifically, as the
number of GPS
seconds since 00:00:00 UTC, January 6, 1980. The next event duration field
corresponds to a 24-bit field. Herein, the next event duration field indicates
the
duration of the next event in hours, minutes, and seconds (for example,
wherein the
format is in 6 digits, 4-bit BCD = 24 bits). The title length field specifies
the length (in
bytes) of the title text field. Herein, the value '0' indicates that there are
no titles
existing for the corresponding event. The title text field indicates the title
of the cor-
responding event in event title in the format of a multiple string structure
as defined in
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ATSC A/65C [x].
[168] FIG. 22 illustrates an exemplary bit stream syntax structure of an MH
system time
descriptor according to the present invention. The MH system time descriptor()
shall
be used as the ensemble level descriptor() within the SMT. Herein, the
MH system time descriptor() provides information on current time and date. The
MH system time descriptor() also provides information on the time zone in
which the
transmitting system (or transmitter) transmitting the corresponding broadcast
stream is
located, while taking into consideration the mobile/portable characterstics of
the MH
service data. The fields included in the MH system time descriptor() will now
be
described in detail.
[169] The descriptor tag field corresponds to an 8-bit unsigned integer
having the value
TBD, which identifies the current descriptor as the MH system time
descriptor(). The
descriptor length field also corresponds to an 8-bit unsigned integer, which
indicates
the length (in bytes) of the portion immediately following the descriptor
length field
up to the end of the MH system time descriptor(). The system time field
corresponds
to a 32-bit unsigned integer quantity. The system time field represents the
current
system time and, more specifically, as the number of GPS seconds since
00:00:00
UTC, January 6, 1980. The GPS UTC offset field corresponds to an 8-bit
unsigned
integer, which defines the current offset in whole seconds between GPS and UTC
time
standards. In order to convert GPS time to UTC time, the GPS UTC offset is
subtracted from GPS time. Whenever the International Bureau of Weights and
Measures decides that the current offset is too far in error, an additional
leap second
may be added (or subtracted). Accordingly, the GPS UTC offset field value will
reflect the change.
[170] The time zone offset polarity field is a 1-bit field, which indicates
whether the time
of the time zone, in which the broadcast station is located, exceeds (or leads
or is
faster) or falls behind (or lags or is slower) than the UTC time. When the
value of the
time zone offset polarity field is equal to '0', this indicates that the time
on the
current time zone exceeds the UTC time. Therefore, the time zone offset
polarity
field value is added to the UTC time value. Conversely, when the value of the
time zone offset polarity field is equal to '1', this indicates that the time
on the
current time zone falls behind the UTC time. Therefore, the time zone offset
polarity
field value is subtracted from the UTC time value.
[171] The time zone offset field is a 31-bit unsigned integer quantity.
More specifically,
the time zone offset field represents, in GPS seconds, the time offset of the
time zone
in which the broadcast station is located, when compared to the UTC time. The
daylight savings field corresponds to a 16-bit field providing information on
the
Summer Time (i.e., the Daylight Savings Time). The time zone field corresponds
to a
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(5x8)-bit field indicating the time zone, in which the transmitting system (or
transmitter) transmitting the corresponding broadcast stream is located.
[172] FIG. 23 illustrates segmentation and encapsulation processes of a
service map table
(SMT) according to the present invention. According to the present invention,
the SMT
is encapsulated to UDP, while including a target IP address and a target UDP
port
number within the IP datagram. More specifically, the SMT is first segmented
into a
predetermined number of sections, then encapsulated to a UDP header, and
finally en-
capsulated to an IP header. In addition, the SMT section provides signaling in-
formation on all virtual channel included in the MH ensemble including the cor-
responding SMT section. At least one SMT section describing the MH ensemble is
included in each RS frame included in the corresponding MH ensemble. Finally,
each
SMT section is identified by an ensemble id included in each section.
According to the
embodiment of the present invention, by informing the receiving system of the
target
IP address and target UDP port number, the corresponding data (i.e., target IP
address
and target UDP port number) may be parsed without having the receiving system
to
request for other additional information.
[173] FIG. 24 illustrates a flow chart for accessing a virtual channel
using FIC and SMT
according to the present invention. More specifically, a physical channel is
tuned
(S501). And, when it is determined that an MH signal exists in the tuned
physical
channel (S502), the corresponding MH signal is demodulated (S503).
Additionally,
FIC segments are grouped from the demodulated MH signal in sub-frame units
(S504
and S505). According to the embodiment of the present invention, an FIC
segment is
inserted in a data group, so as to be transmitted. More specifically, the FIC
segment
corresponding to each data group described service information on the MH
ensemble
to which the corresponding data group belongs.
[174] When the FIC segments are grouped in sub-frame units and, then,
deinterleaved, all
service information on the physical channel through which the corresponding
FIC
segment is transmitted may be acquired. Therefore, after the tuning process,
the
receiving system may acquire channel information on the corresponding physical
channel during a sub-frame period. Once the FIC segments are grouped, in S504
and
S505, a broadcast stream through which the corresponding FIC segment is being
transmitted is identified (S506). For example, the broadcast stream may be
identified
by parsing the transport stream id field of the FIC body, which is configured
by
grouping the FIC segments. Furthermore, an ensemble identifier, a major
channel
number, a minor channel number, channel type information, and so on, are
extracted
from the FIC body (5507). And, by using the extracted ensemble information,
only the
slots corresponding to the designated ensemble are acquired by using the time-
slicing
method, so as to configure an ensemble (5508).
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[1751 Subsequently, the RS frame corresponding to the designated ensemble
is decoded
(S509), and an IP socket is opened for SMT reception (S510). According to the
example given in the embodiment of the present invention, the SMT is
encapsulated to
UDP, while including a target IP address and a target UDP port number within
the IP
datagram. More specifically, the SMT is first segmented into a predetermined
number
of sections, then encapsulated to a UDP header, and finally encapsulated to an
IP
header. According to the embodiment of the present invention, by informing the
receiving system of the target IP address and target UDP port number, the
receiving
system parses the SMT sections and the descriptors of each SMT section without
requesting for other additional information (S511).
[1761 The SMT section provides signaling information on all virtual channel
included in
the MH ensemble including the corresponding SMT section. At least one SMT
section
describing the MH ensemble is included in each RS frame included in the cor-
responding MH ensemble. Also, each SMT section is identified by an ensemble id
included in each section. Furthermore each SMT provides IP access information
on
each virtual channel subordinate to the corresponding MH ensemble including
each
SMT. Finally, the SMT provides IP stream component level information required
for
the servicing of the corresponding virtual channel. Therefore, by using the
information
parsed from the SMT, the IP stream component belonging to the virtual channel
requested for reception may be accessed (S513). Accordingly, the service
associated
with the corresponding virtual channel is provided to the user (S514).
[1771 Hereinafter, a digital broadcast receiving system according to an
embodiment of the
present invention will be described in detail, based upon the description of
the present
invention with reference to FIG. 1 to FIG. 24. Therefore, the description of
FIG. 1 to
FIG. 24 may be partially or entirely applied to the digital broadcast
receiving system
according to the embodiment of the present invention. Evidently, the scope of
the appe
nded claims and their equivalents will not depart from the description of the
present
invention.
[1781 FIG. 25 shows a protocol stack of an MH system according to one
embodiment of
the present invention. Hereinafter, with reference to FIG. 25, a brief
description will be
given of the protocol stack of the MH system according to one embodiment of
the
present invention.
[1791 According to one embodiment of the present invention, a definition is
given of a
technology relating to encryption or decryption of data requiring a
conditional access
before data of an IP level, RTP level and raw level are transmitted through an
MH
transport layer and physical layer. Also, a definition is given of a signaling
method for
implementation of the above technology (for example, a protocol established
between
an MH encryption/decryption layer and an MH signaling layer, or the like).
Further, a
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definition is given of a method of controlling a conditional access-applied
service
when being outputted to an external interface.
[180] The term "conditional access" is used throughout this specification.
The "conditional
access" corresponds to a state in which mobile service data was encrypted (for
example, scrambled) so that it can be used by only a specific user or specific
digital
broadcast receiver. For example, the "conditional access" may correspond to a
case
where a conditional access function was set by a conditional access system
(CAS) or a
control access system (CAS).
[181] Also, the term "control data" is used throughout this specification.
The "control data"
corresponds to data required to remove the conditional access function of data
to which
the conditional access is applied. The "control data" may be named a "key
value" and
may be composed of, for example, an entitlement management message (EMM), en-
titlement control message (ECM), or the like. Further, the ECM may include a
control
word (CW).
[182] FIG. 26 is a block diagram showing the configuration of a digital
broadcast receiver
according to one embodiment of the present invention. Hereinafter, a function
of the
digital broadcast receiver according to one embodiment of the present
invention
processing conditional access-applied mobile service data will be described
with
reference to FIG. 26. For reference, the digital broadcast receivers of FIGs.
1 and 26
are similar in that they process a mobile digital broadcast, but the digital
broadcast
receiver of FIG. 26 is particularly characterized by that it can also process
conditional
access-applied mobile service data. Also, those skilled in the art will
readily appreciate
the operation of the digital broadcast receiver of FIG. 26 by referring to the
entire de-
scription of this specification. Further, the scope of the present invention
is not limited
to contents described in the drawings and should be in principle interpreted
based on
contents described in the appended claims.
[183] As shown in FIG. 26, the digital broadcast receiver according to one
embodiment of
the present invention, denoted by reference numeral 2600, includes a receiving
module
2610, MH signaling DB 2620, user interface/controller 2630, MH TP/IP-based
signaling decoder 2640, transport handler 2650, secure handler 2660,
application
decoder 2670, post processor/output module 2680, and so forth. For reference,
in FIG.
26, a dotted line indicates the flow of data controlling each module, and a
solid line
indicates the flow of actual data being transmitted.
[184] The receiving module 2610 includes a tuner 2611, operation controller
2612, VSB
demodulator 2613, equalizer 2614, MH block decoder 2615, RS frame decoder
2616,
known sequence detector 2617, and signaling decoder 2618.
[185] The user interface/controller 2630 includes an application manager
2631 and a user
interface 2632. The MH TP/IP-based signaling decoder 2640 includes an MH
transport
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signaling decoder 2641 and an IP-based signaling decoder 2642.
[186] The transport handler 2650 includes an MH TP demux 2651, IP data
handler 2652,
UDP data handler 2653, file delivery handler 2654, stream delivery handler
2655, and
MH encrypt/decrypt handler 2656.
[187] The secure handler 2660 includes a smart card interface 2661, secure
signaling DB
2662, copy protection handler 2663, and MH encrypt/decrypt handler 2656. For
reference, an embedded secure processor may be used instead of the smart card
interface 2661.
[188] The application decoder 2670 includes an application handler 2671,
audio decoder
2672, video decoder 2673, and data decoder 2674.
[189] The tuner 2611 of the digital broadcast receiver 2600 according to
one embodiment
of the present invention receives a broadcast signal into which mobile service
data and
main service data are multiplexed. Of course, a module taking charge of this
function
may be named a reception unit.
[190] The RS frame decoder 2616 extracts transmission parameter channel
(TPC) signaling
information and fast information channel (FIC) signaling information from a
data
group in the received mobile service data. Of course, a module taking charge
of this
function may be named an extractor. Also, a separate FIC decoder may be
additionally
provided to extract the FIC signaling information.
[191] The MH transport signaling decoder 2641 acquires a program table
describing virtual
channel information and a service of an ensemble, which is a virtual channel
group of
the received mobile service data, using the extracted fast information channel
signaling
information. Of course, a module taking charge of this function may be named
an
acquirer.
[192] On the other hand, the program table may correspond to a service map
table (SMT)
that is a table about configuration information of the mobile service data,
and this SMT
may be configured, for example, as in FIG. 17 or FIG. 27.
[193] The transport handler 2650 and/or secure handler 2660 detects a
conditional access
descriptor distinctively defining respective levels at which the mobile
service data was
encrypted, using the acquired program table. Of course, a module taking charge
of this
function may be named a detector. The conditional access descriptor will be
described
later in detail with reference to FIG. 28.
[194] Also, the transport handler 2650 and/or secure handler 2660 controls
such that the
encrypted mobile service data is decrypted correspondingly to an encrypted
level
thereof, using information of the detected conditional access (CA) descriptor.
Of
course, a module taking charge of this function may be named a controller.
[195] Therefore, according to one embodiment of the present invention, in
an MH digital
broadcasting environment, only a broadcast receiver authorized to use a
conditional
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access-applied service (for example, an encrypted service, scrambled service,
or the
like) can use that service. Also, according to one embodiment of the present
invention,
a definite signaling method for implementation of such a technology is
defined.
[196] On the other hand, the above-stated data group may include, for
example, a plurality
of known data sequences, and the transmission parameter channel signaling in-
formation and the fast information channel signaling information may be
designed to
be placed, for example, between a first known data sequence and a second known
data
sequence, among the known data sequences.
[197] Therefore, a known data detector of the digital broadcast receiver
according to one
embodiment of the present invention may detect known data in the received
broadcast
signal, and an equalizer of the digital broadcast receiver according to this
embodiment
may channel-equalize mobile service data corresponding to the detected known
data
using the detected known data. For reference, the functions of the known data
detector
and equalizer were adequately described in the description of FIG. 1.
[198] Moreover, according to this embodiment, the equalizer can improve
equalization
performance by using a known data symbol sequence inputted from the known data
detector.
[199] Hereinafter, the operation of the broadcast receiver capable of
processing the
conditional access-applied service will be described in more detail with
reference to
FIG. 26.
[200] The MH signaling DB 2620 is a database that stores MH signaling data
received in
non-IP or IP form and provides the stored data as needed.
[201] The MH transport signaling decoder 2641 processes non-IP MH signaling
in-
formation among MH signaling information, and the IP-based signaling decoder
2642
processes IP-based MH signaling information among the MH signaling
information.
[202] The MH TP demux 2651 processes an MH transport packet (TP) extracted
from an
RS frame, which is an output of the RS frame decoder 2616, and the IP data
handler
2652 processes an IP datagram to be delivered to an IP layer, in the MH TP.
The UDP
data handler 2653 processes a UDP datagram to be delivered to a UDP layer, in
the IP
datagram.
[203] The file delivery handler 2654 processes a file to be delivered to a
file transfer
protocol layer, in the UDP datagram. The stream delivery handler 2655
processes data
to be delivered to an RTP layer (for example, a stream layer for real-time
services), in
the UDP datagram.
[204] The application manager 2631 manages display of a service guide, and
user input
signals related to channel setup, etc. through the service guide. The
application decoder
2670 manages middle ware and decoders for output of services in an MH
broadcasting
system. The post processor/output module 2680 is an interface that post-
processes
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decoded services and outputs various data to an external device.
[205] In particular, modules taking charge of main functions in connection
with the present
invention may be the MH encrypt/decrypt handler 2656, smart card interface
2661,
secure signaling DB 2662, copy protection handler 2663, etc., the functions of
which
will hereinafter be described in more detail.
[206] The MH encrypt/decrypt handler 2656 controls such that services to
which a
conditional access is applied, among MH services, are encrypted and decrypted
corre-
spondingly to the levels of respective layers.
[207] The secure signaling DB 2662 is a database that stores data required
to encrypt or
decrypt the conditional access-applied services, or high value services, among
the MH
services, and data required to securely process the corresponding services,
and
provides the stored data as needed.
[208] The smart card interface 2661 signifies a processor for processing
data needed to be
securely processed, and may be replaced by an embedded secure processor.
[209] The copy protection handler 2663 functions to, for transmission of
the high value
services to an external interface, encrypt the high value services and process
control
data required for the encryption.
[210] On the other hand, in order to implement a conditional access
function, there is a
need for various additional information such as information related to device
and user
authentication, information about a reception authority level of the user, and
a control
word (may be referred to as, for example, a "key") which is used for
encryption and
decryption.
[211] In other words, the control data is composed of an entitlement
management message
(EMM), entitlement control message (ECM), or the like, and the ECM includes a
control word. This control data may be transmitted in an electronic service
guide
(ESG) or may be transmitted in other ways.
[212] The digital broadcast receiver 2600 receiving the control data stores
the control data
in the MH signaling DB 2620 or the secure signaling DB 2662, which is a
separate
secure storage space. In some cases, the digital broadcast receiver 2600 may
receive
and use the control data in real time.
[213] Accordingly, in the case where an authorized digital broadcast
receiver intends to use
a conditional access-applied service, it may extract control data
corresponding to the
service from the MH signaling DB 2620 or secure signaling DB 2662 or may
extract
the control data corresponding to the service in real time.
[214] Also, the extracted control data is delivered to the MH
encrypt/decrypt handler 2656,
which then removes the conditional access function of the corresponding
service using
the delivered control data.
[215] On the other hand, a packet level structure of an MH encrypted
physical layer will
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hereinafter be described briefly with reference to FIG. 2.
[216] In the case where the conditional access is applied, an encrypted MH
service, a
control word required to decrypt the encrypted MH service, and other control
data
required for the conditional access are transmitted to a digital broadcast
receiver side
through an MH payload area shown in FIG. 2. That is, the conditional access-
applied
MH service is transmitted through the MH payload area after being encrypted,
and the
control data for setting and release of the conditional access function is
also
transmitted through the MH payload area.
[217] Hereinafter, a detailed description will be given of concrete data or
signaling method
required to process a conditional access-applied service in an MH digital
broadcasting
environment.
[218] FIG. 27 shows another embodiment of a bit stream syntax of a service
map table
(referred to hereinafter as an "SMT") according to one embodiment of the
present
invention, and FIG. 28 shows the syntax of a conditional access descriptor
according to
one embodiment of the present invention. Hereinafter, with reference to FIGs.
27 and
28 (and FIG. 17 as a subsidiary), an illustrative description will be given of
a table and
descriptor required to implement the conditional access function.
[219] According to one embodiment of the present invention, an SMT (for
example, shown
in FIG. 17 or 27) indicative of the structures of MH services is transmitted.
The SMT
defines various information required in a process of processing MH services
carried
through an RS frame. For example, the MH transport signaling decoder 2641 in
FIG.
26 may process the SMT. This SMT is designable to notify information about
conditional access-applied services, among MH services carried through the cor-
responding RS frame. In particular, the SMT delivers control data required for
processing of the conditional access function to a digital broadcast receiver
side
through the conditional access descriptor illustrated in FIG. 28. Of course,
the control
data may be transmitted to the digital broadcast receiver side through an ESG.
[220] The SMT of FIG. 27 can be understood with reference to the SMT of
FIG. 17, and a
supplementary description will hereinafter be given centering around some
other
fields.
[221] In FIG. 27, a "service provider id" field indicates information
identifying a service
provider, a "number of ensemble" field indicates the number of ensembles
carried
through this table, a "physical freq idx" field indicates the index of a
physical frequen
cy at which a specific ensemble is transmitted, an "ensemble id" field
indicates in-
formation identifying at least one ensemble, a "number of service" field
indicates the
number of services belonging to a specific ensemble, and a
"number of target IP address" field indicates the number of target IP
addresses
belonging to a specific service. The remaining fields shown in FIG. 27 will be
readily
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understood through the field description of FIG. 17.
[222] Also, information required to access a conditional access-applied
service can be par-
ticularly included in the descriptor of FIG. 28, which may be named a
conditional
access descriptor for convenience. It should be noted here that this name is
nothing but
one example. Also, for the convenience of description, the term "MH CA
descriptor"
may replace the conditional access descriptor.
[223] The conditional access descriptor shown in FIG. 28 includes
information identifying
each level at which mobile service data was encrypted, and information about
control
data which is used for decryption of the encrypted mobile service data.
[224] In more detail, as shown in FIG. 28, a "descriptor tag" field
indicates that this
descriptor is an MH CA descriptor, a "descriptor length" field indicates a
length
(expressed by, for example, bytes) from this field to a last field of this
descriptor, a
"CA System ID" field indicates the type of a CA system associated with an ECM
or
EMM, an "ECM EMM flag" field indicates whether the current MH CA Descriptor
is a descriptor of the ECM or a descriptor of the EMM. For example, the
"ECM EMM flag" field signifies that the MH CA Descriptor is the descriptor of
the
ECM when the value thereof is '0', and that the MH CA Descriptor is the
descriptor
of the EMM when the value thereof is '1'. Of course, these numerical values
are
nothing but examples.
[225] An "encrypt level flag" field corresponds to information identifying
each level at
which mobile service data was encrypted or the conditional access was applied.
For
example, this field indicates "No Encryption" when it has a value '000', "IP
Level
Encryption" when '001', "RTP(Stream) Level Encryption" when '010', "Raw Level
Encryption" when '011', and "reserved" when 'others'.
[226] An "IP flag" field indicates whether information of a "destination IP
address" field
is present in the current MH CA Descriptor. For example, when the "IP flag"
field
has a value '0', it indicates that information of an "IP version flag" field
and the in-
formation of the "destination IP address" field are not present. In this case,
the ECM
or EMM is transmitted to a digital broadcast receiver side using the same IP
address as
"destination IP address" of the corresponding service and a port number
different
from "destination port number" of the corresponding service.
[227] In contrast, when the "IP flag" field has a value '1', it indicates
that the information
of the "IP version flag" field and the information of the "destination IP
address"
field are present.
[228] The "IP version flag" field indicates the version of the "destination
IP address".
For example, the "IP version flag" field indicates that an IPv4 address has
been used
when the value thereof is '0', and that an IPv6 address has been used when the
value
thereof is '1'.
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[229] The "destination IP address" field indicates a destination IP address
of an IP
datagram in which the ECM or EMM is carried. A "destination port number" field
indicates a destination port number of a UDP datagram in which the ECM or EMM
is
carried, and a "private data byte" field indicates data individually defined
by a
conditional access system (CAS).
[230] The conditional access descriptor MH CA Descriptor defined in this
manner may
correspond to a descriptor in the SMT shown in FIG. 17 or 27. For detailed
example,
the conditional access descriptor may be defined as any one of a component
level
descriptor, virtual channel level descriptor or ensemble level descriptor of
the SMT
shown in FIG. 17 or as any one of a service provider descriptor, ensemble
descriptor,
service descriptor or target IP address descriptor of the SMT shown in FIG.
27.
[231] In the case where the conditional access descriptor is defined as the
service provider
descriptor of the SMT, the conditional access function operates with respect
to all data
corresponding to a specific service provider. On the other hand, in the case
where the
conditional access descriptor is defined as the ensemble descriptor of the
SMT, the
conditional access function operates with respect to all data corresponding to
a specific
ensemble.
[232] Also, in the case where the conditional access descriptor is defined
as the service
descriptor of the SMT, the conditional access function operates with respect
to all data
corresponding to a specific service. Of course, this service may correspond to
a virtual
channel. Also, in the case where the conditional access descriptor is defined
as the
target IP address descriptor of the SMT, the conditional access function
operates with
respect to all data corresponding to a specific target IP address.
[233] FIG. 29 shows the structure of an RS frame according to one
embodiment of the
present invention, and FIG. 30 shows an MH TP format according to one
embodiment
of the present invention. Hereinafter, with reference to FIGs. 29 and 30, a
description
will be given of a packet level structure of an MH encrypted transport layer
according
to one embodiment of the present invention.
[234] For reference, FIGs. 3 and 29 show RS frame structures, in which FIG.
3 shows an
example of the structure of an RS frame including no conditional access-
applied data
and FIG. 29 shows an example of the structure of an RS frame including
conditional
access-applied data.
[235] FIG. 29 shows the format of an RS frame that carries data
corresponding to an MH
ensemble corresponding to each MH frame, which may be an output of an MH
physical layer subsystem. As shown in FIG. 29, one RS frame can carry a
plurality of
MH services, each of which includes a plurality of IP datagrams. Also, the RS
frame is
composed of a two dimensional byte array of 187*N bytes, and each row of the
RS
frame constitutes an MH transport packet in view of an MH transport layer.
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[236] On the other hand, one MH TP has a format including an MH TP header
of 2 bytes
and an MH TP payload of (N-2) bytes, which is illustrated in FIG. 30. When
stuffing
bytes are k bytes long, the MH TP header may be (N-2-k) bytes long.
[237] In FIG. 30, a "type indicator" field indicates the data type of
payload data. The "type
indicator" field signifies that the MH TP carries signaling data when the
value thereof
is '000', and that the MH TP carries an IP datagram when the value thereof is
'001'.
[238] An "error indicator" field indicates whether there is an error
detected in this MH TP,
a "stuff indicator" field indicates whether there are stuffing bytes included
in this MH
TP, a "pointer field" field indicates a start point of a new packet in the
payload of this
MH TP, and a "stuffing bytes" field may become the start of the payload as
needed
(when there is stuffing of k bytes in the MH TP).
[239] FIG. 31 shows the structure of data encrypted at an IP level,
according to one
embodiment of the present invention, FIG. 32 shows the structure of data
encrypted at
an RTP level, according to one embodiment of the present invention, and FIG.
33
shows the structure of data encrypted at a raw level, according to one
embodiment of
the present invention. Hereinafter, with reference to FIGs. 31 to 33, a
description will
be given of processes of performing encryption and decryption at the
respective levels.
[240] Data in an IP datagram, such as video, audio, timed text, etc., is
transmitted through a
layer for a real-time application, such as Real-time Transport Protocol (RTP).
For
example, the video, audio and timed text data are delivered to an MH TP layer
through
the stream delivery handler 2655, UDP data handler 2653 and IP data handler
2652
shown in FIG. 26.
[241] FIG. 31 illustrates a method of packetizing real-time application
data into an MH TP
after applying a conditional access to the data (for example, encrypting the
data) at the
IP level.
[242] First, with reference to FIG. 31, etc., a description will given of a
process of
encrypting mobile service data at the IP level by a digital broadcast
transmitter or the
like.
[243] Real-time application data of an MH service delivered through an RTP
layer is
packetized into an MH TP via a UDP layer and IP layer. At this time, in the
case where
the conditional access is applied to the MH service at the IP level, an IP
datagram,
which is an output of the IP layer, is first encrypted at an MH
encrypt/decrypt layer
before being packetized into an MH TP. The IP datagram encrypted in this
manner is
packetized into an MH TP at the MH TP layer and then transmitted to a physical
layer.
[244] Next, with reference to FIG. 31, etc., a description will given of a
process of
decrypting mobile service data encrypted at the IP level by a digital
broadcast receiver
or the like.
[245] The digital broadcast receiver determines whether the conditional
access was applied
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to a given MH service, using the conditional access descriptor (see FIG. 28)
included
in the SMT (see FIG. 17 or 27). In particular, in the case where the
"encrypt level flag" value is '001', the digital broadcast receiver performs
decryption
at the IP level. For the decryption at the IP level by the digital broadcast
receiver, the
MH TP demux 2651 extracts the given MH service and control data (for example,
an
ECM, EMM, or the like) from an RS frame, and the MH encrypt/decrypt handler
2656
decrypts the encrypted MH service using the control data processed by the
secure
handler 2660. Then, the IP data handler 2652 receives the decrypted MH
service, and
the other modules of the digital broadcast receiver control such that the MH
service is
normally outputted. Of course, the encryption process may be performed in the
reverse
order of the above-stated decryption process.
[246] FIG. 32 illustrates a method of packetizing real-time application
data into an MH TP
after applying a conditional access to the data (for example, encrypting the
data) at the
RTP (stream) level.
[247] First, with reference to FIG. 32, etc., a description will given of a
process of
encrypting mobile service data at the RTP level by a digital broadcast
transmitter or the
like.
[248] In the case where the conditional access is applied to real-time
application data of an
MH service at the RTP (stream) level, RTP (stream) data, which is an output of
the
RTP layer, is encrypted at the MH encrypt/decrypt layer. The encrypted data is
packetized into an MH TP at the MH TP layer via the UDP layer and IP layer and
then
transmitted to the physical layer.
[249] Of course, in the case where the conditional access is not applied,
the RTP (stream)
data, which is the output of the RTP layer, bypasses the MH encrypt/decrypt
layer. The
RTP data, not encrypted, is packetized into an MH TP at the MH TP layer via
the UDP
layer and IP layer and then transmitted to the physical layer.
[250] Next, with reference to FIG. 32, etc., a description will given of a
process of
decrypting mobile service data encrypted at the RTP level by a digital
broadcast
receiver or the like.
[251] The digital broadcast receiver determines whether the conditional
access was applied
to a given MH service, using the conditional access descriptor (see FIG. 28)
included
in the SMT (see FIG. 17 or 27). In particular, in the case where the
"encrypt level flag" value is '010', the digital broadcast receiver performs
decryption
at the RTP level. For the decryption at the RTP level by the digital broadcast
receiver,
the MH TP demux 2651 extracts the given MH service and control data (for
example,
an ECM, EMM, or the like) from an RS frame, and the encrypted MH service is
delivered to the MH encrypt/decrypt handler 2656 through the IP data handler
2652
and UDP data handler 2653. The MH encrypt/decrypt handler 2656 decrypts the
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encrypted MH service using the control data processed by the secure handler
2660.
Then, the stream delivery handler 2655 receives the decrypted MH service, and
the
other modules of the digital broadcast receiver control such that the MH
service is
normally outputted. Of course, the encryption process may be performed in the
reverse
order of the above-stated decryption process.
[252] FIG. 33 illustrates a method of packetizing real-time application
data into an MH TP
after applying a conditional access to the data (for example, encrypting the
data) at the
raw level.
[253] First, with reference to FIG. 33, etc., a description will given of a
process of
encrypting mobile service data at the raw level by a digital broadcast
transmitter or the
like.
[254] In the case where the conditional access is applied at the raw level,
raw data of a real-
time application of an MH service is encrypted at the MH encrypt/decrypt layer
before
being encapsulated at the RTP layer. The encrypted data is packetized into an
MH TP
at the MH TP layer via the RTP layer, UDP layer and IP layer and then
transmitted to
the physical layer.
[255] Of course, in the case where the conditional access is not applied,
the raw data,
which is an output of an application layer, bypasses the MH encrypt/decrypt
layer, and
is packetized into an MH TP at the MH TP layer via the RTP layer, UDP layer
and IP
layer and then transmitted to the physical layer.
[256] Next, with reference to FIG. 33, etc., a description will given of a
process of
decrypting mobile service data encrypted at the raw level by a digital
broadcast
receiver or the like.
[257] The digital broadcast receiver determines whether the conditional
access was applied
to a given MH service, using the conditional access descriptor (see FIG. 28)
included
in the SMT (see FIG. 17 or 27). In particular, in the case where the
"encrypt level flag" value is '011', the digital broadcast receiver performs
decryption
at the raw level. For the decryption at the raw level by the digital broadcast
receiver,
the MH TP demux 2651 extracts the given MH service and control data (for
example,
an ECM, EMM, or the like) from an RS frame, and the encrypted MH service is
delivered to the MH encrypt/decrypt handler 2656 through the IP data handler
2652,
UDP data handler 2653 and stream delivery handler 2655. The MH encrypt/decrypt
handler 2656 decrypts the encrypted MH service using the control data
processed by
the secure handler 2660. Then, the application decoder 2670 receives the
decrypted
MH service, and the other modules of the digital broadcast receiver control
such that
the MH service is normally outputted. Of course, the encryption process may be
performed in the reverse order of the above-stated decryption process.
[258] FIG. 34 illustrates an AES-CTR mode encryption process which is
applicable to one
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embodiment of the present invention, FIG. 35 illustrates an AES-CTR mode
decryption process which is applicable to one embodiment of the present
invention,
FIG. 36 is a table defining an AES-CTR mode counter value which is applicable
to one
embodiment of the present invention, and FIG. 37 illustrates a process of
processing a
residue block in an AES-CTR mode encryption/decryption process which is
applicable
to one embodiment of the present invention. Hereinafter, with reference to
FIGs. 34 to
37, a description will be given of a concrete encryption/decryption method for
imple-
mentation of a conditional access function according to one embodiment of the
present
invention.
[259] For example, Advanced Encryption Standard (AES)-CounTeR (CTR)-128 may
be
used as an encryption/decryption algorithm which is applied to an MH service
for the
conditional access thereof. In this case, encryption may be performed at the
IP level,
RTP level and raw level, as shown in FIG. 34, and decryption may be reversely
performed at the IP level, RTP level and raw level, as shown in FIG. 35.
[260] Notably, in the case of using the AES-CTR-128 algorithm shown as in
FIGs. 34 and
35, an initial counter value is required, and the present invention newly
defines the
counter value as in FIG. 36.
[261] In FIG. 36, a "type indicator" field indicates the type of an
encrypted stream, a
"system time" field indicates a system time of a superframe, and a
"destination port
number" field indicates a destination port number of an encrypted stream. The
use of
the counter value defined in this manner makes it possible to uniquely define
a counter
value of each data block composed of 16 bytes. It is also possible to increase
efficiency.
[262] Also, the "type indicator" field shown in FIG. 36 may be designed to
correspond to
the "type indicator" field of the MH TP shown in FIG. 30. In the case of being
designed like this, the "type indicator" field in FIG. 36 signifies that an MH
TP of an
encrypted stream carries signaling data when the value thereof is '000', and
that an
MH TP of an encrypted stream carries an IP datagram when the value thereof is
'001'.
[263] Therefore, according to one embodiment of the present invention, as a
counter value
to be used in an encryption/decryption algorithm (for example, the AES-CTR-128
algorithm or the like), different counter values can be set according to an MH
TP
carrying signaling data and an MH TP carrying an IP datagram, particularly by
using
the type indicator of each MH TP. Further, there is an advantage that the
encryption/
decryption algorithm is designable to operate depending on MH TPs having such
different counter values.
[264] On the other hand, data to be encrypted and decrypted according to
one embodiment
of the present invention is partitioned into 128-bit blocks and then encrypted
and
decrypted. As a result, the last data block may not be up to 128 bits. For
preparation for
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this case, a design may be made to XOR an output value from an AES encryption
block and the value of a residue data block beginning with most significant
bits, as
shown in FIG. 37.
[265] FIG. 38 is a detailed view of an SMT including a conditional access
descriptor
according to one embodiment of the present invention, and FIG. 39 shows the
structure
of an RS frame including an MH service to which a conditional access is
applied,
according to one embodiment of the present invention. Hereinafter, in
conjunction with
FIGs. 38 and 39, an illustrative description will be given of a process of
processing a
conditional access-applied service in a mobile digital broadcasting
environment.
[266] Each MH CA Descriptor shown in FIG. 38 indicates a level at which the
conditional access is applied, control data required in a decryption process,
and so
forth. The MH CA Descriptor 1 provides information about a conditional access-
applied ECM with respect to only a service whose target IP address is
200.200.200.5,
among services whose ensemble ID is 1 and major channel number and minor
channel
number are 30-5.
[267] The MH CA Descriptor 2 provides information about a conditional
access-applied
ECM with respect to all services whose ensemble ID is 1 and major channel
number
and minor channel number are 30-6. That is, the MH CA Descriptor 2 provides
the
information about the conditional access-applied ECM with respect to services
whose
target IP addresses are 200.200.200.6 and 200.200.200.7.
[268] On the other hand, as stated previously, a digital broadcast receiver
according to one
embodiment of the present invention can determine whether the conditional
access-
applied service was encrypted at which one of the raw level, RTP level and IP
level, by
using "encrypt level flag" of the MH CA Descriptor. At this time, the digital
broadcast receiver needs control data for authorization of access to
conditional access-
applied services, and so forth. That is, the digital broadcast receiver can
acquire EMM
information for authorization of reception of all services whose ensemble ID
is '1',
using the fact that the value of ECM EMM flag of the MH CA Descriptor 3 is
'1'.
[269] FIG. 39 shows the structure of an RS frame including services in
which the ensemble
ID is '1' and the conditional access is applied, in the SMT shown in FIG. 38.
[270] In the case where a service 2 is selected in the RS frame structure
of FIG. 39, a
digital broadcast receiver according to one embodiment of the present
invention can
confirm that MH CA Descriptor associated with the service 2 is present in the
SMT
of FIG. 38. That is, the digital broadcast receiver can confirm that the
conditional
access was applied to the service 2.
[271] At this time, the digital broadcast receiver can confirm from the
MH CA Descriptor 2 associated with the service 2 that an ECM (including a
control
word, etc.) required for removal of the conditional access function of the
service 2 is
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transmitted through a destination IP address '200.200.200.9' and a destination
port
number '1000'. Also, the digital broadcast receiver can confirm that an EMM,
among
control data required for authorization of access to the encrypted service 2,
is
transmitted through a destination IP address '200.200.200.10' and a
destination port
number '1000'. Therefore, using the confirmed ECM, EMM, etc., the digital
broadcast
receiver can remove the conditional access function of the encrypted service
2.
[272] FIG. 40 is a flowchart illustrating a control method of a digital
broadcast receiver
according to one embodiment of the present invention. With reference to FIG.
40, a
brief description will hereinafter be given of the control method of the
digital broadcast
receiver according to one embodiment of the present invention. For reference,
FIGs. 40
and 45 relate to a method invention, which can be interpreted with the
description of
the above-stated object invention supplementarily applied thereto.
[273] The digital broadcast receiver according to one embodiment of the
present invention
decodes an RS frame (S4000). The digital broadcast receiver extracts an SMT as
a
result of the decoding (S4001) and parses the extracted SMT to check
information
required for removal of a conditional access function (S4002).
[274] The digital broadcast receiver extracts MH TPs according to the SMT
to extract
control data, etc. (S4003). The digital broadcast receiver parses an MH TP
header
(S4004) to determine the value of a "Type Indicator" field (S4005). When it is
determined at step S4005 that the field value is '000', the digital broadcast
receiver
processes signaling data (S4017). When it is determined at step S4005 that the
field
value is '001', the digital broadcast receiver determines the value of an
'encrypt level flag' field of a conditional access descriptor (corresponding
to
MH CA Descriptor shown in FIG. 28) of the SMT (S4006).
[275] When it is determined at step S4006 that the value of the 'encrypt
level flag' field is
'001', the digital broadcast receiver decrypts encrypted mobile service data
at an IP
level (S4007). That is, the digital broadcast receiver decrypts an IP
datagram.
[276] In the case where it is determined at step S4006 that the value of
the
'encrypt level flag' field is not '001', the digital broadcast receiver
processes an IP
datagram (S4008) and processes a UDP datagram (S4009). Also, the digital
broadcast
receiver determines whether data transmitted from a digital broadcast
transmitter or the
like is a file or stream (S4010). When it is determined at step 4010 that the
transmitted
data is the stream, the digital broadcast receiver determines the value of the
'encrypt level flag' field (S4012). In contrast, when it is determined at step
4010 that
the transmitted data is the file, the digital broadcast receiver processes the
file (S4011).
[277] In the case where it is determined at step S4012 that the value of
the
'encrypt level flag' field is '010', the digital broadcast receiver decrypts
encrypted
mobile service data at an RTP level (S4013). That is, the digital broadcast
receiver
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decrypts stream data.
[278] In the case where it is determined at step S4012 that the value of
the
'encrypt level flag' field is not '010', the digital broadcast receiver
processes the
stream (S4014) and determines the value of the 'encrypt level flag' field
(S4016).
When it is determined at step S4016 that the value of the 'encrypt level flag'
field is
'011', the digital broadcast receiver decrypts encrypted mobile service data
at a raw
level (S4015). That is, the digital broadcast receiver decrypts raw data.
[279] In contrast, when it is determined at step S4016 that the value of
the
'encrypt level flag' field is not '011', the digital broadcast receiver
controls such that
an application is processed suitably to a corresponding format (S4018). This
format
may be, for example, a file, stream, signaling data, or the like.
[280] The present method may be designed such that the step S4010 of
determining
whether the transmitted data is the file or stream or the step S4011 is
deleted and the
step S4012 is performed immediately subsequently to the step S4009.
[281] FIG. 41 is a table defining copy control information (CCI) according
to one
embodiment of the present invention, FIG. 42 illustrates an encryption mode
indicator
(EMI) shown in FIG. 41, FIG. 43 illustrates an analog protection system (APS)
shown
in FIG. 41, and FIG. 44 illustrates a constrained image trigger (CIT) shown in
FIG. 41.
Hereinafter, with reference to FIGs. 41 to 44, a description will be given of
a method
capable of securely setting copy protection when a conditional access-applied
MH
service is transmitted to an external interface, according to one embodiment
of the
present invention.
[282] As stated previously, a conditional access-applied MH service is
transmitted to
digital broadcast receivers, and only an authorized user or digital broadcast
receiver
can use the MH service. Notably, in order to prevent an illegal copy from
occurring
when the MH service is transmitted through an external interface, one
embodiment of
the present invention defines new signaling data.
[283] The signaling data for the illegal copy prevention may be illustrated
as in FIG. 41.
For example, this signaling data may be copy control information (CCI)
composed of 8
bits.
[284] On the other hand, an encryption mode indicator (EMI), among CCI
fields shown in
FIG. 41, may be configured as in FIG. 42. This EMI is information for copy
control of
digital data, which is used to control a copy authority of a digital data
output.
[285] Also, an analog protection system (APS), among the CCI fields shown
in FIG. 41,
may be configured as in FIG. 43. This APS is used to control a copy authority
of an
analog data output.
[286] Also, a constrained image trigger (CIT), among the CCI fields shown
in FIG. 41,
may be configured as in FIG. 44. This CIT is used to control a copy authority
of an
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image of a high definition analog component output.
[287] The CCI may be transmitted under the condition of being not
encrypted, but a digital
broadcast receiver has to confirm whether the transmitted CCI is legal data
transmitted
from a service provider. Therefore, according to one embodiment of the present
invention, the CCI may be transmitted in an ECM or a descriptor of an SMT or
using a
secure scheme such as public key infrastructure (PKI).
[288] For example, according to one embodiment of the present invention, an
EMI defining
a copy authority of a digital data output, an APS defining a copy authority of
an analog
data output, and a CIT defining a copy authority of a high definition analog
component
data output may be additionally defined in the conditional access descriptor
shown in
FIG. 28.
[289] In this case, when a service with CCI is outputted to a variety of
external interfaces
such as IEEE-1394, USB, DVI, HDMI and component (RGB, YPbPr), the copy
protection handler 2663 can output a stream or service with a copy authority
set therein
to the external interfaces according to the type of data using the CCI (for
example,
defined as a conditional access descriptor). For reference, the copy
protection handler
2663 may be named a transmission unit.
[290] Also, the CCI may be stored in the secure signaling DB 2662 or other
storages, and a
digital broadcast receiver according to one embodiment of the present
invention may
use the stored CCI to output a service to an external interface.
[291] FIG. 45 is a flowchart illustrating a control method of a digital
broadcast receiver and
digital broadcast transmitter according to one embodiment of the present
invention.
With reference to FIG. 45, a detailed description will hereinafter be given of
the
control method of the digital broadcast receiver and digital broadcast
transmitter
according to one embodiment of the present invention.
[292] The digital broadcast transmitter according to one embodiment of the
present
invention generates a broadcast signal including a conditional access
descriptor
indicating whether mobile service data was encrypted (S4501) and transmits the
generated broadcast signal including the conditional access descriptor to a
digital
broadcast receiver (S4502).
[293] Here, the conditional access descriptor includes information
identifying each level at
which the mobile service data was encrypted, and information about control
data
which is used for decryption of the encrypted mobile service data. Also, the
conditional access descriptor may be configured as in FIG. 28, and may be
referred to
as MH CA Descriptor.
[294] The digital broadcast receiver according to one embodiment of the
present invention
receives a broadcast signal into which mobile service data and main service
data are
multiplexed (S4503) and extracts TPC/FIC signaling information from a data
group in
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the received mobile service data (S4504).
[295] Also, the digital broadcast receiver acquires a program table
describing virtual
channel information and a service of an ensemble, which is a virtual channel
group of
the received mobile service data, using the extracted FIC signaling
information
(S4505). Then, the digital broadcast receiver detects a conditional access
descriptor
indicating whether the mobile service data was encrypted, using the acquired
program
table (S4506). For detailed example, the conditional access descriptor may be
a
descriptor distinctively defining respective levels at which the mobile
service data was
encrypted.
[296] Then, the digital broadcast receiver controls such that the encrypted
mobile service
data is decrypted, using information of the detected conditional access
descriptor
(S4507). For detailed example, at step S4507, the digital broadcast receiver
may
control such that the encrypted mobile service data is decrypted
correspondingly to an
encrypted level thereof.
[297] For reference, the program table may correspond to the SMT shown in
FIG. 17 or 27,
and the conditional access descriptor may correspond to the MH CA Descriptor
shown in FIG. 28.
[298] In this regard, the step 54507 may further include determining a
level at which the
mobile service data was encrypted, using, for example, the MH CA Descriptor of
the
SMT, and decrypting the encrypted mobile service data at a level corresponding
to the
determination result using the information about the control data.
[299] As described above, according to one embodiment of the present
invention, it is
possible to readily decrypt mobile service data encrypted, for example, at a
raw level,
RTP level and IP level irrespective of the positions of the levels in a mobile
digital
broadcasting environment.
[300] Further, according to one embodiment of the present invention, mobile
service data
requiring no conditional access is designed to bypass an MH encrypt/decrypt
layer,
thereby enabling compatibility with existing systems.
[301] In addition, according to one embodiment of the present invention, an
illegal copy
can be prevented even when mobile service data is outputted to an external
interface.
[302] The present method invention can be implemented in the form of
program commands
executable by a variety of computer means, and recorded on a computer-readable
recording medium. The computer-readable recording medium can include program
commands, data files, data structures, etc. individually or in combination.
The program
commands recorded on the medium may be ones specially designed and configured
for
the present invention or ones known and available to those skilled in computer
software. Examples of the computer-readable recording medium include magnetic
media such as a hard disk, a floppy disk and a magnetic tape, optical media
such as a
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compact disc read only memory (CD-ROM) and a digital versatile disc (DVD),
magneto-optical media such as a floptical disk, and hardware devices specially
configured to store and execute program commands, such as a ROM, a random
access
memory (RAM) and a flash memory. Examples of the program commands include
high-level language codes that can be executed by a computer using an
interpreter, etc.,
as well as machine language codes such as those produced by a compiler. The
above-
stated hardware devices can be configured to operate as one or more software
modules
to perform the operation of the present invention, and vice versa.
[303] Although the present invention has been described in conjunction with
the limited
embodiments and drawings, the present invention is not limited thereto. Those
skilled
in the art will appreciate that various modifications, additions and
substitutions are
possible from this description.
[304] Therefore, the scope of the present invention should not be limited
to the description
of the exemplary embodiments and should be determined by the appended claims
and
their equivalents.
Mode for the Invention
[305] A mode for invention is descripbed in above "Best Mode".
Industrial Applicability
[306] As described above, the present invention can be applied to a digital
broadcasting
system.
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