Note: Descriptions are shown in the official language in which they were submitted.
CA 02488327 2004-11-23
[0001) This application claims the benefit of the Korean Patent Application
No. 10-
2003-0083688, filed on November 24, 2003, which is hereby incorporated by
reference.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present invention relates to an enhanced 8-VSB reception system and
E8-VSB data demultiplexing method, by which a plurality of enhanced data,
which are
encoded at different code rates and are multiplexed with MPEG data encoded by
the
previous ATSC 8VSB system to be transmitted, can be received.
Discussion of the Related Art
[0003] Generally, the United States of America (U.S.A.) has adopted the ATSC
(advanced television systems committee) 8VSB (vestigial sideband) transmission
system as
standards for terrestrial digital broadcasting in 1995 and has started the
broadcasting since
1998. The Republic of Korea has adopted the standards of the ATSC 8VSB
transmission
system and has started its experimental broadcasting on May, 1995. The
experimental
broadcasting was switched to test broadcasting systems on August 31, 2000, and
the regular
broadcasting has been broadcasted by major broadcasting stations since
October, 2001.
[0004] FIG. I is a block diagram of an ATSC 8VSB transmission system according
to a related art.
[0005] Referring to FIG. 1, an ATSC data randomizer 101 randomizes inputted
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MPEG video/voice data to output to a Reed-Solomon coder 102. The Reed-Solomon
coder
102 performs Reed-Solomon coding on the randomized data, adds 20-byte parity
code to
the coded data, and then outputs the corresponding data to a data interleaver
103. The data
interleaver 103 performs interleaving on the data outputted from the Reed-
Solomon coder
102 to change a sequence of the data and then outputs the interleaved data to
a trellis coder
104. The trellis coder 104 converts the interleaved data to symbols from bytes
and then
performs trellis coding on the converted data to output to a multiplexer 105.
The
multiplexer 105 multiplexes a trellis-coded symbol column with sync signals to
output to a
pilot inserter 106. The pilot inserter 106 adds a pilot signal to the
multiplexed symbol
column to output to a VSB modulator 107. The VSB modulator 107 modulates the
symbol
column outputted from the pilot inserter 106 into an 8VSB signal of an
intermediate
frequency band to output to an RF converter 108. And, the RF converter 108
converts the
received 8VSB signal of the intermediate frequency band to an RF band signal
to transmit
via antenna.
[0006] The ATSC 8VSB transmission system developed for the HD (high
definition) broadcast transmits MPEG-2 digital video and Dolby digital sound.
Recently, as
the Internet globally prevails in use, the demand for interactive broadcast is
rising, and
various supplementary services are requested. In order to meet such demands,
many efforts
are made to develop the system enabling to provide separate supplementary
services as well
as the MPEG-2 digital video and Dolby digital sound on the same channel.
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[0007] In this case, unlike the normal video/sound data, the supplementary
data
such as a program execution file, stock information, and the like should be
transmitted with
a lower error rate. In case of the video/sound data, errors failing to be
perceptible to human
eyes and ears are no big deal. Yet, in case of the supplementary data, one bit
error
occurrence may raise a serious problem.
[0008] Hence, in a new E8-VSB transmission system compatible with the previous
ATSC 8VS system, supplementary data are coded by '/2 and '/~ code rates,
respectively, the
supplementary data are multiplexed by 164-byte packet unit according to a
previously
determined multiplexing format, the multiplexed data are further pre-processed
to output as
an MPEG transport packet format, the pre-processed enhanced data are
multiplexed by 188-
byte packet unit according to the previously determined multiplexing format,
and the
multiplexed data by 188-byte packet unit are then transmitted. Such technology
has been
filed by the present applicant (Korean Patent Application No. 10-2003-0017834,
filed on
March 21, 2003).
[0009] In the applicant's previous patent application, data are divided into
main
data and enhanced data. The main data mean the foregoing-explained previous
MPEG-2
video and Dolby digital sound data. And, the enhanced data mean'/ enhanced
data coded
at '/Z code rate and '/4 enhanced data coded at '/, code rate. In the
applicant's previous patent
application, the '/z enhanced data and the '/4 enhanced data are called '/2
supplementary data
and '/4 supplementary data, respectively. Yet, their meanings are identical to
each other.
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[0010] For convenience of explanation in the following description, as
explained in
applicant's previous patent application, a transmitted signal resulting from
multiplexing
enhanced data and main data (or normal data) is called an enhanced 8-VSB
(hereinafter
abbreviated E8-VSB) signal. Besides, the enhanced data and the main data can
be used as
the enhanced data and the main data, respectively.
[0011] FIG. 2 is a block diagram of a general ATSC 8VSB receiver.
[0012] Referring to FIG. 2, once a VSB-modulated RF signal is received via
antenna, an RF tuner 201 selects an RF signal of a specific channel only by
tuning and then
converts it to an IF signal to output to an IF mixer 202. The IF mixer 202
down-coverts the
IF signal outputted from the tuner 201 to a near baseband (BB) signal to
output to a
demodulator 203. The demodulator 203 performs VSB demodulation on the near BB
signal
to output to an equalizer 204.
[0013] The equalizer 204 compensates channel distortion included in the VSB-
demodulated signal to output to an 8VSB channel decoder 205. The 8VSB channel
decoder
205 converts the channel distortion compensated signal to an MPEG transport
(TP) type
signal to output.
[0014] However, in the general ATSC 8VSB receiver shown in FIG. 2, in case
that
the E8-VSB signal corresponding to the multiplexed signal of the enhanced data
and the
main data is transmitted, the enhanced data packets will be recognized as null
packets via
PID (Packet Identification) of MPEG transport header and gracefully discarded.
Therefore
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the legacy ATSC 8-VSB receiver will receive the main data and discard the
enhanced data
as null packets.
SUMMARY OF THE INVENTION
[0015] Accordingly, the present invention is directed to an enhanced 8-VSB
reception system and E8-VSB data demultiplexing method that substantially
obviate one or
more problems due to limitations and disadvantages of the related art.
[0016] An object of the present invention is to provide an enhanced 8-VSB
reception system and E8-VSB data demultiplexing method, by which an enhanced
VSB
signal can be stably received as well as a previous ATSC 8VSB signal.
[0017] Additional advantages, objects, and features 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 may be
learned from
practice of the invention. The objectives and other advantages 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.
[0018) To achieve these objects and other advantages and in accordance with
the
purpose of the invention, as embodied and broadly described herein, an E8-VSB
reception
system according to the present invention, which receives an E8-VSB signal
transmitted
from an E8-VSB transmission system which multiplexes a first enhanced data
coded at '/Z
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code rate and a second enhanced data coded at '/4 code rate by 164-byte packet
unit
according to a multiplexing format of E8-VSB map information inserted in a
reserved area
of a field sync signal and further pre-processes the multiplexed enhanced data
packets to
output as 188-byte transport packet and multiplexes the pre-processed enhanced
data and a
normal data by 188-byte transport packet unit according to the multiplexing
format of the
E8-VSB map information inserted in the reserved area of the field sync signal,
includes a
tuner receiving an E8-VSB modulated 1ZF signal via antenna, the tuner
selecting an 1RF
signal of a specific channel by tuning, the tuner converting the selected RF
signal to an IF
signal to output, a demodulator converting the IF signal outputted from the
tuner to a
baseband signal to output, an E8-VSB map recovery detecting the field sync
signal and a
field identifying signal within a frame from an output of the demodulator by
performing
frame sync recovery, the E8-VSB map recovery extracting to decode the E8-VSB
map
information inserted in the reserved area of the field sync signal using the
detected field
sync and identifying signals, the E8-VSB map recovery generating various kinds
of E8-
VSB data attribute, a channel equalizer compensating channel distortion
included in the
VSB-modulated signal by receiving the data modulator output and the E8-VSB
data
attribute of the E8-VSB map recovery, and an E8-VSB channel
decoder/demultiplexer
decoding a normal data, a first enhanced data, and a second enhanced data from
a signal
equalized in the channel equalizer using the E8-VSB map information of the E8-
VSB map
recovery, the E8-VSB data attributes, and the field sync signal.
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[0019] The E8-VSB map information is Kerdock-coded to be inserted in the
reserved area of the field sync signal and includes information of each packet
number of the
first and second enhanced data transmitted on one field, the multiplexing
format of the first
and second enhanced data, and the multiplexing format of the enhanced data and
the main
data.
[0020] The E8-VSB map recovery includes a frame sync recovery detecting the
field sync signal and the field identifying signal indicating an even or odd
field by
performing frame synchronization from data symbols outputted from the
demodulator, a
map information extractor extracting the E8-VSB map information inserted in
the field sync
signal from the data symbols outputted from the demodulator using the field
sync signal, a
Kerdock decoder decoding the extracted map information by Kerdock decoding
algorithm,
a current map decider deciding the E8-VSB map information of a current field
from the
Kerdock-decoded E8-VSB map information by the field sync signal and the field
identifying signal, and an E8-VSB data attribute generator generating the E8-
VSB data
attributes indicating attributes of a symbol or a byte unit of the E8-VSB data
by the E8-VSB
map information of the current field and the field sync signal.
[0021] The E8-VSB data attribute generator includes a main and enhanced mux
packet processor generating to output a 188-byte attribute packet including
attribute
information of an E8-VSB data of byte unit by receiving the E8-VSB map
information of
the current field outputted from the current map decider and the field sync
signal outputted
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from the frame sync recovery, an ATSC RS codes outputting a 207-byte attribute
packet by
discarding the first byte of an input packet corresponding to 0x47 MPEG sync
byte and
adding 20 bytes having an attribute of a normal data to the 188-byte attribute
packet, an
ATSC data interleaves performing ATSC data byte interleaving on the 207-byte
attribute
packet to output by byte unit, and a byte-symbol converter converting the
interleaved data
of the byte unit to a symbol unit to output as the E8-VSB symbol attribute.
[0022] 'The main and enhanced mux packet processor includes an enhanced packet
generator generating an attribute packet of 164-byte unit having the attribute
information
only indicating the first or second enhanced data according to distribution
formations and
rates of first and second enhanced data packets of the current field within
the E8-VSB map
information of the current field, a null enhanced RS codes expanding 20 bytes
by copying
the attribute of each of the packets to an enhanced data attribute packet
having the attribute
information of the enhanced data outputted from the enhanced packet generator,
an
enhanced data interleaves performing enhanced data interleaving on data
outputted from the
null enhanced RS codes, a null-bit expander inserting a null bit in an
interleaved byte
outputted from the enhanced data interleaves to fit the first and second
enhanced data to
expand, a null MPEG header inserter inserting a byte of a normal data
attribute
corresponding to an MPEG header of 4 bytes in front of each 184 bytes
outputted from the
null bit expander, and a main and enhanced packet multiplexes multiplexing to
output a
normal data packet and an enhanced data packet outputted from the null MPEG
header
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inserter by 188-byte packet unit using the map information of the current
field and the field
sync signal.
[0023] The main and enhanced packet generator seeks a number (I-17 of first
enhanced data of 164-byte packet unit and a number (Q) of second enhanced data
of 164-
byte packet unit from E8-VSB map information based on the field sync signal
outputted
from E8-VSB map recovery to find a number (2P) of packets of 188-byte unit
allocated to
enhanced data in one VSB field (2P=2H-+-4Q), and the mmain and enhanced packet
multiplexer distributes to multiplex normal data packets and enhanced data
packets by a
distribution method selection included in the E8-VSB map information.
[0024] The E8-VSB channel decoder/demultiplexer includes a main data decoder
performing Viterbi decoding, 12-way deinterleaving, ATSC data byte
deinterleaving, ATSC
RS decoding, and ATSC data derandomizing on the equalized data output
according to the
E8-VSB data attribute, and an enhanced data decoder decoding to separate the
first and
second enhanced data by sequentially performing ATSC parity removal, ATSC data
derandomizing, null bit removal, enhanced data deinterleaving, enhanced RS
decoding, and
enhanced packet demultiplexing on the ATSC data deinterleaved E8-VSB data
outputted
from the main data decoder by packet unit.
[0025] And, the enhanced data decoder includes an ATSC parity remover removing
an ATSC RS parity portion from the ATSC byte deinterleaved packet data
outputted from
the main data decoder, an ATSC data derandomizer performing the ATSC data
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derandomizing on the ATSC RS parity portion removed data, a main and enhanced
mux
packet processor generating to output an attribute packet including attribute
information of
an E8-VSB data of byte unit by receiving the E8-VSB map information of a
current field
and the field sync signal, a null bit remover removing entire bits of the
normal data byte and
insignificant bits of the first and second enhanced data bytes to reconfigure
the data of the
byte unit into a first significant enhanced byte and a second significant
enhanced byte by
using E8-VSB byte attribute outputted from the main and enhanced mux packet
processor,
an enhanced data deinterleaver performing the enhanced data deinterleaving on
enhanced
data of the byte unit configured with significant bits outputted from the null
bit remover, an
enhanced RS decoder performing the enhanced RS decoding on the enhanced
deinterleaved
data, and an enhanced packet demultiplexer separating the enhanced RS decoded
data into a
first enhanced data packet and a second enhanced data packet to output using
the E8-VSB
map information and the field sync signal outputted from the E8-VSB map
recovery.
[0026] In another aspect of the present invention, an E8-VSB data
demultiplexing
method of an E8-VSB reception system which receives an E8-VSB signal
transmitted from
an E8-VSB transmission system, the E8-VSB transmission system which
multiplexes a first
enhanced data coded at '/2 code rate and a second enhanced data coded at '/4
code rate by
164-byte packet unit according to a multiplexing format of E8-VSB map
information
inserted in a reserved area of a field sync signal and further pre-processes
the multiplexed
enhanced data packets to output as 188-byte transport packet and multiplexes
the pre-
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processed enhanced data and a normal data by 188-byte transport packet unit
according to
the multiplexing format of the E8-VSB map information inserted in the reserved
area of the
field sync signal. The E8-VSB data demultiplexing method of the E8-VSB
reception
system includes a step (a) of detecting the field sync signal and a field
identifying signal
indicating an even or odd field within a frame from received and demodulated
E8-VSB data
by performing frame sync recovery, a step (b) of extracting to decode the E8-
VSB map
information inserted in the reserved area of the field sync signal using the
detected field
sync and identifying signals detected in the step (a) and generating various
kinds of E8-VSB
data attributes, a step (c) of compensating channel distortion included in the
VSB-
modulated signal by receiving the various kinds of the E8-VSB data attributes,
and a step
(d) of receiving the E8-VSB data attributes synchronized with an E8-VSB symbol
equalized
data in the step (c) and decoding a normal data, a first enhanced data, and a
second
enhanced data from the equalized signal using the E8-VSB map information of
the E8-VSB
map recovery, the E8-VSB data attributes, and the field sync signal.
[0027] The step (b) includes a step (b-1) of extracting the E8-VSB map
information
inserted in the field sync signal from the data symbols outputted from the
demodulator
using the field sync signal, a step (b-2) of decoding the extracted map
information by
Kerdock decoding algorithm, a step (b-3) of deciding the E8-VSB map
information of a
current field from the Kerdock-decoded E8-VSB map information by the field
sync signal
and the field identifying signal, and a step (b-4) of generating the E8-VSB
data attributes by
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the E8-VSB map information of the current field and the field sync signal.
[0028] The step (b-4) includes the steps of generating to output a 188-byte
attribute
packet including attribute information of an E8-VSB data by receiving the E8-
VSB map
information of the current field outputted from the current map decider and
the field sync
signal outputted from the (b-3) step, outputting a 207-byte attribute packet
by discarding the
first byte of an input packet corresponding to 0x47 MPEG sync byte and adding
20 bytes
having an attribute of a normal data to the I 88-byte attribute packet,
performing ATSC data
byte interleaving on the 207-byte attribute packet to output by byte unit, and
converting the
interleaved data of the byte unit to a symbol unit to output as the E8-VSB
data symbol
attribute.
[0029] The attribute packet generating step includes the steps of generating
an
enhanced data attribute packet of 164-byte unit having the attribute
information only
indicating the first or second enhanced data according to distribution
formations and rates of
first and second enhanced data packets of the current field within the E8-VSB
map
information of the current field, expanding 20 byte by copying the attribute
of each of the
packets to the enhanced data attribute packet having the attribute information
of the
enhanced data only, performing enhanced data interleaving on parity-expanded
data
outputted from the expanding step, expanding an interleaved byte outputted
from the
enhanced data interleaving step by inserting a null bit in the interleaved
byte to fit the first
and second enhanced data, inserting a 4-byte MPEG header value indicating a
normal data
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byte in each 184 bytes outputted from the null bit expanding step, and
multiplexing to
output a normal data packet and an enhanced data packet having the null MPEG
header
inserted by 188-byte packet unit using the map information of the current
field and the field
sync signal.
[0030] And, the step (d) includes a step (d-1 ) of main data decoding by
sequentially
performing Viterbi decoding, 12-way deinterleaving, ATSC data byte
deinterleaving, ATSC
RS decoding, and ATSC data derandomizing on the equalized E8-VSB symbol
according to
the E8-VSB data attributes, and a step (d-2) of decoding to separate the first
and second
enhanced data by sequentially performing ATSC parity removal, ATSC data
derandomizing,
null bit removal, enhanced data interleaving, enhanced RS decoding, and
enhanced packet
demultiplexing on the ATSC data deinterleaved E8-VSB data outputted by packet
unit in
the step (d-1).
[0031] In the enhanced packet demultiplexer, a number (H) of first enhanced
data
packets of 164-byte unit and a number (Q) of second enhanced data packets of
164-byte
unit are sought from the E8-VSB map outputted from the E8-VSB map recovery
block.
[0032] In the null bit remover of the enhanced data decoder, the normal data
packets, the MPEG headers added to the enhanced data packets and the null bits
inserted for
byte expansion at the transmitter are removed using the E8-VSB map, the E8-VSB
data
attributes and field sync signal outputted from the E8-VSB map recovery.
[0033] It is to be understood that both the foregoing general description and
the
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following detailed description of the present invention are exemplary and
explanatory and
are intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] The accompanying drawings, which are included to provide a further
understanding of the invention and are incorporated in and constitute a part
of this
application, illustrate embodiments of the invention and together with the
description serve
to explain the principle of the invention. In the drawings:
[0035] FIG. I is a block diagram of an ATSC 8VSB transmission system according
to a related art;
[0036] FIG. 2 is a block diagram of a general ATSC 8VSB receiver;
[0037] FIG. 3 is a block diagram of an E8-VSB transmission system according to
the present invention;
[0038] FIG. 4 is a detailed block diagram of a main and enhanced mux packet
processor of the system in FIG. 3;
[0039] FIG. SA is a structural diagram of a data frame of ATSC 8VSB
transmission
system;
[0040] FIG. SB is a structural diagram of a field sync signal in FIG. SA;
[0041] FIG. 6 is a detailed block diagram of an E8-VSB pre-processor in FIG.
4;
[0042] FIG. 7A is a diagram of multiplexing '/z enhanced data packets and '/4
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enhanced data packets by a uniform distribution;
[0043] FIG. 7B is a diagram of multiplexing '/z enhanced data packets and '/4
enhanced data packets by a grouping distribution;
[0044] FIG. 7C is a diagram of multiplexing '/x enhanced data packets and '/a
enhanced data packets by an alternative distribution;
[0045] FIG. 8 is a block diagram of an E8-VSB reception system according to
the
present invention;
[0046] FIG. 9 is a detailed block diagram of an E8-VSB map recovery unit in
FIG.
8;
[0047) FIG. 10 is a detailed block diagram of an E8-VSB data attribute
generator in
FIG. 9;
[0048) FIG. 11 is a detailed block diagram of an E8-VSB channel
decoder/demultiplexer in FIG. 8;
[0049] FIG. 12 is a detailed block diagram of a main and enhanced mux packet
processor in FIG. 10 and FIG. 11;
[0050) FIG. 13 is a diagram of byte expansion and removal of %Z enhanced data;
[0051] FIG. 14 is a diagram of byte expansion and removal of'/a enhanced data;
[0052] FIG. 15A is a diagram of a group distribution in multiplexing '/2
enhanced
data packets and '/4 enhanced data packets;
[0053] FIG. 15B is a diagram of an alternative distribution in multiplexing
'/Z
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enhanced data packets and '/4 enhanced data packets;
[0054] FIG. 16A is a diagram of a multiplexing format of normal data packets
and
enhanced data packets, in which an exemplary distribution having a pattern
according to
conditions is shown; and
[0055] FIG. 16B is a diagram of a multiplexing format of normal data packets
and
enhanced data packets, in which an exemplary uniform distribution is shown.
DETAILED DESCRIPTION OF THE INVENTION
[0056] 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.
[0057] For the understanding of an E8-VSB reception system of the present
invention, the E8-VSB transmission system and multiplexing process disclosed
in the
Korean Patent Application No. 10-2003-0017834 is explained with reference to
the attached
drawings as follows.
[0058] First of all, in the Korean Patent Application No. 10-2003-0017834, the
recent MPEG-4 video or various supplementary data (e.g., program execution
file, stock
information, etc.) can be transferred via enhanced data as well as the
previous MPEG-2
video and Dolby sound data. In doing so, error correction encoding is
additionally
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performed on the enhanced data except main data. And, '/z enhanced data and
'/< enhanced
data mean data on which encoding is additionally performed at '/2 and '/4 code
rates,
respectively, unlike the main data. Hence, the enhanced data is provided with
reception
performance superior to that of the main data in noise generated from channel
and
interference due to mufti-path. Specifically, the'/4 enhanced data coded at'/4
code rate has
performance more excellent than that of the % enhanced data coded at %Z code
rate.
[0059] Referring to FIG. 3, a main and enhanced mux packet processor 301
multiplexes '/2 enhanced data and '/4 enhanced data by 164-byte packet unit
and further pre-
processes the multiplexed enhanced data to output as a 188-byte transport
packet format and
multiplexes the pre-processed enhanced data and main data by 188-byte packet
unit again,
and then outputs the data to a first encoding unit 302. The first encoding
unit 302 includes a
randomizer 302-1, Reed-Solomon codes 302-2, and byte interleaves 302-3
sequentially
connected to an output end of the main and enhanced mux packet processor 301.
The first
encoding unit 302 sequentially performs data randomization, Reed-Solomon
coding, and
data interleaving on a data packet outputted from the main and enhanced mux
packet
processor 301 to output to an E8-VSB convolutional codes 303. The E8-VSB
convolutional
codes 303 converts the interleaved data of byte unit outputted from the first
encoding unit
302 to symbols, performs convolutional coding on an enhanced data symbol only,
converts
the symbol to data of byte unit, and then outputs the converted data to a
first decoding unit
304.
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[0060] The first decoding unit 304 includes a byte deinterleaver 304-1, Reed-
Solomon parity remover 304-2, and derandomizer 304-3 sequentially connected to
an
output end of the E8-VSB convolutional coder 303. The first decoding unit 304
sequentially performs data deinterleaving, Reed-Solomon parity removal, and
derandomization on the data of byte unit outputted from the E8-VSB
convolutional coder
303 to output to an 8VSB transmission unit 100.
[0061] The 8VSB transmission unit 100 having the same configuration shown in
FIG. 1 sequentially performs data randomization, Reed-Solomon coding, data
interleaving,
trellis coding, and the like again on the data of which Reed-Solomon parity
was removed by
the first decoding unit 304. In the FIG. 3, ATSC derandomizer 304-3 of the
first decoding
unit 304 and ATSC randomizer 101 of the 8VSB transmission unit 100 can be
skipped
together.
[0062] FIG. 4 is a detailed block diagram of the main and enhanced mux packet
processor 301. After'/Z enhanced data and'/4 enhanced data have been
multiplexed by 164-
byte packet unit and further pre-processed by the E8-VSB pre-processor, main
data is
multiplexed with the pre-processed enhanced data by 188-byte packet unit. In
doing so, a
frame configuring one picture in the VSB transmission system includes two data
fields.
Each of the data fields includes one field sync segment and 312 data segments.
And, one
data segment includes a data segment sync signal of 4-symbols and data of 828-
symbols.
[0063] Referring to FIG. 4, a main data buffer 401 temporarily stores main
data
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inputted as a packet of 188-byte unit and then outputs the main data to a main
and enhanced
packet multiplexer 405. A '/Z enhanced data buffer 402 temporarily stores '/2
enhanced data
inputted as a packet of 188-byte unit. A '/4 enhanced data buffer 403
temporarily stores '/<
enhanced data inputted as a packet of 188-byte unit and then outputs the data
to an E8-VSB
pre-processor 404.
[0064] The E8-VSB pre-processor 404 multiplexes the '/z enhanced data
outputted
from the '/Z enhanced data buffer 402 and the '/4 enhanced data outputted from
the '/4
enhanced data buffer 403 with each other by 164-byte packet unit according to
a previously
determined format, further pre-processes to the same structure of an IvIPEG
transport packet
of the main data, and then outputs the converted data to the main and enhanced
packet
multiplexer 405.
[0065] The main and enhanced packet multiplexer 405 multiplexes the main data
packet outputted from the main data buffer 401 and the enhanced data packet
outputted
from the E8-VSB pre-processor 404 into 188-byte packet units according to
main/enhanced
data multiplexing information inserted in the field sync signal.
[0066] In doing so, once the number of packets of the enhanced data to be
transmitted on one VSB data field is determined, the E8-VSB transmission
system inserts
main/enhanced data multiplexing map information (hereinafter referred to as E8-
VSB map
information) associated with the multiplexing format and the transport packet
number of the
enhanced data in an unused area within the field sync segment and then
transmits the
CA 02488327 2004-11-23
corresponding signal. Hence, the E8-VSB reception system enables to perform
accurate
demultiplexing to correspond to the field sync.
[0067] FIG. 5A is a structural diagram of a data frame of an ATSC 8VSB
transmission system.
[0068] Referring to FIG. 5, one frame is divided into an odd field and an even
field.
Each of the fields is divided into three hundred thirteen segments. The 313
segments
include one field sync segment containing a training sequence signal and three
hundred
twelve data segments.
[0069] And, one segment includes 832-symbols. In this case, first 4-symbols in
one
segment construct a sync part and a first segment in each field becomes a
field sync part.
[0070] The field sync segment format is shown in FIG. 5B. A segment sync
pattern
exists in first 4-symbols, pseudo random sequences PN 511, PN 63, PN 63, and
PN 63
follow the segment sync pattern, and VSB mode associated information exists in
the next
24-symbols, in turn. In this case, a polarity of the second PN 63 among the
three PN 63
sections is alternately changed. Namely, 'I' is changed into '0' or '0' is
changed into '1'.
Hence, one frame can be divided into even and odd fields according to the
polarity of the
second PN 63.
[0071] Meanwhile, the rest 104-symbols following the 24-symbols where the VSB
mode associated information exists are reserved. And, the last 12-symbols data
of the
previous segment are copied to last 12-symbols of the reserved area.
21
CA 02488327 2004-11-23
[0072) In the present invention, E8-VSB map information including the
multiplexing format and the main/enhanced data multiplexing information
associated with
the transport packet number of the enhanced data is inserted in the first 64-
symbols of the
reserved area within the field sync segment in FIG. SB to be transmitted.
[0073] Namely, 64 two-level symbols of the reserved area within the field sync
segment are used for transmitting E8-VSB map information. The E8-VSB map
information
is inserted by being coded as Kerdock(64,12). A polarity of the Kerdock code
word
becomes reversed in an even (negative PN 63) data field. The Kerdock coding
algorithm is
known to public, of which detailed explanation will be skipped in the
following.
[0074] FIG. 6 is a detailed block diagram of the E8-VSB pre-processor 404.
[0075] Referring to FIG. 6, a '/z MPEG packet converter 501 segments %z
enhanced
data inputted as packets of 188-byte unit into 164-byte units without data
alteration to
output to an enhanced packet multiplexes 503. And, a '/o MPEG packet converter
502
segments '/4 enhanced data inputted as packets of 188-byte unit into 164-byte
units without
data alteration to output to the enhanced packet multiplexes 503.
[0076] The enhanced packet multiplexes 503 multiplexes the '/z and '/4
enhanced
data outputted from the %i and '/4 MPEG packet converters 501 and 502 by 164-
byte packet
unit according to E8-VSB map information within a field sync segment to output
to an
enhanced Reed-Solomon codes 504. The enhanced Reed-Solomon codes 504 performs
Red-Solomon coding on the enhanced data multiplexed in the enhanced packet
multiplexes
22
CA 02488327 2004-11-23
503 and then adds a parity code of 20 bytes thereto, thereby converting the
enhanced data of
164-byte unit to a packet of 184-byte unit to output to an enhanced data
interleaver 505. In
order to enhance performance against burst noise, the enhanced data
interleaver 505
changes a sequence of the data outputted from the enhanced Reed-Solomon coder
504 and
then outputs the sequence-changed data to a null-bit inserter 506.
Subsequently, the null-bit
inserter 506 inserts a null-bit corresponding to the'/z or'/4 enhanced data
outputted from the
enhanced data interleaver 505 to expand a packet and then outputs the expanded
packet to
an MPEG header inserter 507. The MPEG header inserter 507 inserts an MPEG
header of 4
bytes in a front portion of each 184 bytes of the enhanced data having the
null-bit inserted
by the null-bit inserter 506 to make a format identical to that of the MPEG
transport packet
of the main data and then outputs the corresponding data to the main and
enhanced packet
multiplexer 405. This is to discard the packet by checking PID in case that
the previous
VSB receiver receives the enhanced data packet
[0077] When the '/Z enhanced data of 1 byte is inputted, the null-bit inserter
506
inserts a null-bit between the respective bits to expand to 2 bytes. When the
'/e enhanced
data of 1 byte is inputted, the null-bit inserter 506 repeats each bit twice
and inserts null-bits
between the respective bits to expand to 4 bytes. Such a null-bit will be
replaced by a parity
bit by an E8-VSB convolutional coder 303.
[0078] Moreover, the multiplexing information for multiplexing the '/2 and '/4
enhanced data in the enhanced packet multiplexer 503 of the E8-VSB pre-
processor 404
23
CA 02488327 2004-11-23
and the multiplexing information for multiplexing the main data and the
enhanced data in
the main and enhanced packet multiplexer 405 of the main and enhanced mux
packet
processor 301 is called the E8-VSB map information in the present invention.
As
mentioned in the foregoing description, the E8-VSB map information is Kerdock-
coded and
then inserted in the reserved are (bit) within the field sync segment to be
transmitted.
[0079] Meanwhile, a method of multiplexing the '/2 and '/4 enhanced data in
the
enhanced packet multiplexer 503 of the E8-VSB pre-processor 404 is explained
in detail as
follows.
[0080] First of all, the numbers of'/z and'/4 enhanced data packets of 164-
byte unit
multiplexed in the enhanced packet multiplexer 503 within one VSB data field
will be
defined as H and Q, respectively.
[0081] In this case, the null-bit inserter 506 of FIG. 6 inserts a null-bit to
output 2
bytes in case of receiving the'/Z enhanced data of 1 byte or inserts null-bits
to output 4 bytes
in case of receiving the '/4 enhanced data of 1 byte. Since one VSB data field
consists of
three hundred twelve data segments, a maximum value of 'H' becomes 156
(=312/2) if the
'/Z enhanced data is multiplexed only to be transmitted. By the same rule, a
maximum value
of 'Q' becomes 78 (=312/4) in case of transmitting the '/4 enhanced data only.
Namely, if
the '/z enhanced data is transmitted only, it is able to transmit maximum 156-
packets (1-
packet = 164 bytes). And, if the '/4 enhanced data is transmitted only, it is
able to transmit
maximum 78-packets (1-packet = 164 bytes).
24
CA 02488327 2004-11-23
[0082] This can be generalized by the following equation.
[0083] N + 2H + 4Q = 312
[0084] In this case, the number of data segments within one VSB field is 312
resulting from adding the normal data packet number (N), the packet number (H)
of a first
enhanced data, and the packet number (Q) of a second enhanced data to each
other
according to the above expression.
[0085] The Korean Patent Application No. 10-2003-0017834 has proposed methods
of multiplexing '/z and '/4 enhanced data packets in the enhanced packet
multiplexes 503 if
the values of 'H' and 'Q' are determined.
[0086] The first method of uniform multiplexing, as shown in FIG. 7A, is to
multiplex the '/2 and '/4 enhanced data packets with equal interval.
[0087] The second method of grouping multiplexing, as shown in FIG. 7B, is to
multiplex the '/2 and '/4 enhanced data packets by grouping the '/2 enhanced
data packets and
the '/4 enhanced data packets separately. The '/2 enhanced data packets, as
shown in FIG. 7B,
are grouped for one data field to be outputted and the '/4 enhanced data
packets are then
grouped for one data field to be outputted.
[0088] And, the third method of alternate multiplexing, as shown in FIG. 7C,
is to
multiplex the %Z and '/< enhanced data packets alternately. F first of all,
the %z and '/4
enhanced data packets, as shown in FIG. 7C, are alternately multiplexed. Once
either the'/Z
or '/4 enhanced data packets are completely multiplexed, the rest data packets
are
CA 02488327 2004-11-23
multiplexed.
[0089] Namely, FIGs. 7A to 7C show the methods of multiplexing the '/Z and '/4
enhanced data packets that will be transmitted on one VSB data field in case
of H=8 and
Q=2.
[0090] If the numbers H and Q of the '/Z and '/4 enhanced data packets
transmitted
on one VSB data field are determined, the '/2 enhanced data packet number, '/4
enhanced
data packet number, and E8-VSB map information associated with the format used
for the
multiplexing among the above-explained multiplexing methods are inserted in
the reserved
area within the field sync segment to transmit to the E8-VSB reception system
and
outputted to the enhanced packet multiplexes 503 and the main and enhanced
packet
multiplexes 405. The enhanced packet multiplexes 503 then multiplexes the '/2
and '/4
enhanced data packets by the multiplexing format according to the enhanced
data
multiplexing information. In doing so, the format used for the multiplexing
may be fixed to
one of the multiplexing methods (formats) or can be adaptively decided
according to the
numbers of the'/2 and'/4 enhanced data packets multiplexed on one VSB data
field.
[0091] In case that the E8-VSB transmission system according to the present
invention adopts to use one of the three methods only, the values of 'H' and
'Q' need to
exist in the E8-VSB map information within the field sync signal only. Yet, in
case that all
of the three methods are optionally used or in case that two of the three
methods are
optionally used, the information indicating which method is used for the
corresponding
26
CA 02488327 2004-11-23
multiplexing should be added to the E8-VSB map information within the field
sync signal.
[0092] Namely, the information for the transport packet numbers of the '/2 and
'/4
enhanced data within one data field, the information indicating which format
is adopted to
multiplex the '/2 and '/4 enhanced data, and the information indicating which
format is used
for multiplexing the enhanced data and the main data should be contained in
the E8-VSB
map information inserted in the reserved area within the field sync segment.
[0093] FIG. 8 is a block diagram of an E8-VSB reception system according to
the
present invention for receiving an E8-VSB signal transmitted from the E8-VSB
transmission system in FIGS. 3 to 7.
[0094] Referring to FIG. 8, an E8-VSB reception system according to the
present
invention includes a tuner 601, an IF mixer 602, a demodulator 603, an
equalizer 604, an
E8-VSB map recovery 605, and an E8-VSB channel decoder/demultiplexer 606.
Configurations and operations of the tuner 601, IF mixer 602, and demodulator
603 are
equivalent to those in FIG. 2.
[0095] Namely, once an E8-VSB-modulated RF signal is received via antenna, the
tuner 601 selects an RF signal of a specific channel only by tuning and then
converts it to an
IF signal to output to the IF mixer 602. The IF mixer 602 down-coverts the IF
signal
outputted from the tuner 60I to a near baseband (BB) signal to output to the
demodulator
603. The demodulator 603 performs VSB demodulation on the near BB signal to
output to
the equalizer 604 and the E8-VSB map recovery 605. The E8-VSB map recovery 605
27
CA 02488327 2004-11-23
detects E8-VSB map information inserted in a reserved area of a field sync
segment to
output to the equalizer 604 and the E8-VSB channel decoder/demultiplexer 606.
The
equalizer 604 receives the decision feedback from the E8-VSB channel
decoder/demultiplexer 606 at its end and the output of the E8-VSB map recovery
605 and
then compensates channel distortion included in the VSB-demodulated signal to
output to
the E8-VSB channel decoder/demultiplxer 606. Namely, the equalizer 604
performs
enhanced equalization using the output of the E8-VSB map recovery 605 and more
reliable
symbol decisions from the E8-VSB channel decoder/demultiplexer 606.
[0096] FIG. 9 is a detailed block diagram of the E8-VSB map recovery 605.
[0097] Referring to FIG. 9, the E8-VSB map recovery 605 includes an E8-VSB
map extractor 701 extracting E8-VSB map information from data symbols
outputted from
the demodulator 603 or data symbols outputted from the enhanced equalizer 604,
a Kerdock
decoder 702 decoding the extracted E8-VSB map information by Kerdock decoding
algorithm, a frame sync recovery 704 performing frame synchronization from the
data
symbols outputted from the demodulator 603 or the data symbols outputted from
the
enhanced equalizer 604 to output a field sync signal and a field identifying
signal indicating
an even or odd field, a current map deciding unit 703 deciding a current map
by receiving
the E8-VSB map information decoded in the Kerdock decoder 702, the field sync
signal,
and the field identifying signal, and an E8-VSB data attribute generator 705
generating
attribute information of a current E8-VSB data according to the current map
information
28
CA 02488327 2004-11-23
and the field sync signal.
[0098] The E8-VSB map recovery 605 performs an operation of extracting the E8-
VSB map information inserted in a field sync section by the E8-VSB
transmission system.
The E8-VSB data attribute generator 705 of the E8-VSB map recovery 605
generates
information indicating attributes of the respective E8-VSB data to provide to
the equalizer
604 and the E8-VSB channel decoder/demultiplexer 606, thereby intending to
enhance
performance of both of the equalizer 604 and the E8-VSB channel
decoder/demultiplexer
606.
[0099] In order to receive the E8-VSB signal, the E8-VSB map recovery 605 is
essential to the above-configured present invention. For reliable detection of
the E8-VSB
map, E8-VSB map recovery 605 selectively receives its input data between the
input of the
equalizer 604 and the output signal of the equalizer 604.
[00100] Meanwhile, explained in the following is an example that the E8-VSB
map
recovery 605 utilizes the input/output signal of the equalizer.
[00101] The first method enables to selectively use the input or output signal
of the
equalizer 604 as the input data of the E8-VSB map recovery 605 with reference
to a
presence or non-presence of operation of the equalizer 604 and an output SNR
at the rear
end of the equalizer. The second method enables to elicit the E8-VSB map
information of a
currently received signal by providing a pair of E8-VSB map recovery units to
utilize
reliability of outputs from a pair of the E8-VSB map recovery units. And, the
third method
29
CA 02488327 2004-11-23
synchronizes signals of the input and output sides of the equalizer 604 to use
as the input
data of the E8-VSB map recovery 605.
[00102] In doing so, a frame of the VSB signal should be synchronized so that
the
E8-VSB map recovery 605 can recognize the presence of the enhanced mode from
the
received signal. Hence, the frame sync recovery 704 detects the field sync
signal and the
field identifying signal indicating whether the current field is the even or
odd field by
performing frame synchronization from the inputted data symbols and then
outputs them to
the E8-VSB map extractor 701, the current map deciding unit 703, and the E8-
VSB data
attribute generator 705. Namely, it is able to detect whether the current
field is the even or
odd field using the polarity of the second PN 63 in the training signal of the
field sync
signal section.
[00103] The E8-VSB map extractor 701 receives the field sync signal from the
frame
sync recovery 704. If the inputted data symbol indicates the field sync
signal, the E8-VSB
map extractor 701 extracts the E8-VSB map information included in the field
sync signal
section and then outputs the extracted information to the Kerdock decoder 702.
[00104] In doing so, since the extracted E8-VSB map information was
transmitted
from the E8-VSB transmission system by being coded according to the Kerdock
coding
algorithm clearly stated in the E8-VSB specification, the Kerdock decoder 702
decodes the
extracted E8-VSB map information according to the Kerdock decoding algorithm
to output
to the current map deciding unit 703. The current map deciding unit 703
divides the
CA 02488327 2004-11-23
Kerdock-decoded E8-VSB map information into the even field E8-VSB map
information
and the odd field E8-VSB map information by the field sync signal and field
identifying
signal outputted from the frame sync recovery 704 and then decides the E8-VSB
map
information of the current field again. Hence, the decided E8-VSB map
information of the
current field is simultaneously outputted to the E8-VSB channel
decoder/demultiplexer 606
and the E8-VSB data attribute generator 705.
[00105) The E8-VSB data attribute generator 705 generates signals indicating
an
attribute of E8-VSB data at the symbol, byte and packet level based on the E8-
VSB map
information of the current field. Namely, the E8-VSB data attribute generator
705
generates signals indicating whether the symbol, byte or packet is a normal
data (or main
data) or an enhanced data. In case of the enhanced data, the E8-VSB data
attribute
generator 705 generates attribute information of the enhanced data for
indicating whether
the enhanced data is '/~ enhanced data or '/4 enhanced data and then output
the generated
information to the equalizer 604 and the E8-VSB channel decoder/demultiplexer
606.
[00106] FIG. 10 is a detailed block diagram of the E8-VSB data attribute
generator
705.
[00107] Referring to FIG. 10, the E8-VSB data attribute generator 705 includes
a
main and enhanced mux packet processor 801 receiving the E8-VSB map
information of
the current field and the field sync signal to output a 188-byte attribute
packet containing
the attribute information identifiying the normal data, the '/~-rate enhanced
data or the '/4-
31
CA 02488327 2004-11-23
rate enhanced data, a null ATSC RS coder 802 outputting a 207-byte attribute
packet by
discarding the first byte of an input packet corresponding to 0x47 MPEG sync
byte and
adding a parity amount of the ATSC RS coder, i.e., 20 bytes having the
attribute of the
normal data, to the 188-byte attribute packet, an ATSC data interleaver 803
interleaving the
207-byte attribute packet, and a byte-symbol converter 804 converting the
interleaved data
of byte unit to data of symbol unit to output as an attribute of E8-VSB data
symbol. The
E8-VSB symbol attribute is provided to the enhanced equalizer 604 and the
Viterbi decoder
901 ofthe E8-VSB channel decoder/demultiplexer 606.
[00108] The above-configured E8-VSB data attribute generator 705, as shown in
FIG. 10, generates the attribute information of each symbol in a manner of
using the field
sync signal and the E8-VSB map information of the current field.
[00109] Namely, the main and enhanced mux packet processor 801 receives the
field
sync signal and the E8-VSB map information of the current field to output the
attribute
packet constructed with 188 bytes to the null ATSC RS coder 802. The attribute
packet
contains no data information but the attribute information per byte. And, the
attribute also
enables to identify whether each byte is the byte of the normal data, the '/2
enhanced data
coded at '/2 code rate, or the '/4 enhanced data coded at '/< code rate. FIG.
12 is a detailed
block diagram of the main and enhanced mux packet processor 801, which will be
explained in detail later.
[00110] The null ATSC RS coder 802 outputs the 207-byte attribute packet to
the
32
CA 02488327 2004-11-23
ATSC data interleaver 803 by discarding the first byte of an input packet
corresponding to
0x47 MPEG sync byte and adding the parity amount of the ATSC RC coder, i.e.,
20 bytes
having the attribute of the normal data, to the 188-byte attribute packet. The
ATSC data
interleaver 803 performs ATSC data interleaving on the 207-byte attribute
packet to output
to the byte-symbol converter 804. The byte-symbol converter 804 converts the
interleaved
data of byte unit to the data of symbol unit to output as an attribute of the
E8-VSB data
symbol. And, the E8-VSB data symbol amibute is provided to the enhanced
equalizer 604
and the Viterbi decoder 901 of the E8-VSB channel decoder/demultiplexer 606.
[00111] The equalizer 604 receives each attribute of the currently inputted
VSB
symbol from the E8-VSB map recovery 605, thereby enabling to exert
equalization
capability more enhanced than that of the conventional equalizer. Moreover, by
feeding
back a symbol decision of the Viterbi decoder 901 of the E8-VSB channel
decoder/demultiplexer 606 to the equalizer 604, it is able to enhance
equalization
performance. Namely, since the reliability of the enhanced symbols) is higher
than that of
the normal data symbol, the equalizer 604 enables to improve its equalization
performance
using the two kinds of information (i.e., E8-VSB data symbol attribute and
symbol decision
feedback from the Viterbi decoder 901).
[00112] Meanwhile, the E8-VSB channel decoder/demultiplexer 606, as shown in
FIG. 11, has a separate data path to receive an enhanced data as well as a
normal data.
Namely, by decoding or separating a reception signal in a corresponding mode
using the
33
CA 02488327 2004-11-23
E8-VSB map information and E8-VSB data attributes indicating the multiplexing
information of the currently received E8-VSB signal, the E8-VSB reception
system enables
to receive a normal data MPEG TPS # 1, '/2 enhanced data MPEG TPS #2, and '/4
enhanced
data MPEG TPS #3. In this case, the mode indicates one of normal data, the '/Z
enhanced
data, and the '/4 enhanced data.
[00113] FIG. 11 is a detailed block diagram of the E8-VSB channel
decoder/demultiplexer 606.
[00114] Referring to FIG. 11, the E8-VSB channel decoder/demultiplexer 606
includes a main data decoding unit 900 separating to decode the normal data
MPEG TPS #1
from an equalized signal and an enhanced data decoding unit 950 separating to
decode the
enhanced data and separating the decoded data into the '/Z enhanced data MPEG
TPS #2 and
the '/4 enhanced data MPEG TPS #3. The main data decoding unit 900 is the same
as a
channel decoder of the legacy ATSC receiver, but the difference is that the
Viterbi decoder
901 of the main decoding unit 900 decodes both normal data and enhanced data
using E8-
VSB data attributes of symbol unit from E8-VSB data attribute generator 705.
The
enhanced data decoding unit 950 is a data path of decoding the '/Z and '/4
enhanced data.
[00115] The main data decoding unit 900 includes a Viterbi decoder/12-way data
interleaver 901, an ATSC byte deinterleaver 902, an ATSC RS decoder 903, and
an ATSC
data derandomizer 904.
[00116] Namely, as is the same case of the conventional 8VSB channel decoder,
the
34
CA 02488327 2004-11-23
normal data symbol equalized in the equalizer 604 is decoded into the normal
data stream
MPEG TPS #1 via the Viterbi decoder/12-way deinterleaver 901, ATSC data byte
deinterleaver 902, ATSC RS decoder 903, and ATSC data derandomizer 904 of the
main
data decoding unit 900. The transmitted signal from the legacy ATSC 8VSB
transmitter is
decided as the signal having normal data only by the E8-VSB map recovery and
can be
received via the path of the main data decoding unit 900.
[00117] Yet, since the 8VSB signal and the enhanced VSB signal are multiplexed
in
case of the E8-VSB signal, there are two differences in the E8-VSB channel
decoder/demultiplexer 606 compared to the conventional ATSC 8VSB channel
decoder.
One is that decoding appropriate for each E8-VSB symbol should be performed in
the
Viterbi decoder based on the attribute of E8-VSB symbol, and the other is that
a separate
data path for the enhanced data should exist.
[00118] The enhanced data decoding unit 950, which is the data path for
decoding
the enhanced data, includes an ATSC RS parity removing unit 951, an ATSC data
derandomizer 952, a null-bit removing unit 953, an enhanced data deinterleaver
954, an
enhanced RS decoder 955, an enhanced packet demultiplexer 956, and a main and
enhanced
mux packet processor 957.
[00119] Considering the E8-VSB channel decoder/demultiplexer 606 in FIG. 11,
the
E8-VSB symbol equalized in the equalizer 604 and the E8-VSB data symbol
attribute
generated from the E8-VSB map recovery 605 are synchronized to be inputted to
the
CA 02488327 2004-11-23
Viterbi decoder/12-way deinterleaver 901.
[00120] In doing so, since the normal symbol and the enhanced symbol are mixed
in
the equalized symbol inputted to the Viterbi decoder/12-way deinterleaver 901,
the Viterbi
decoder/12-way deinterleaver 901 identifies the normal symbol and the enhanced
symbol
from each other based on the E8-VSB data symbol attribute and then performs
Viterbi
decoding correspondingly. And, the Viterbi decoder/12-way deinterleaver 901
performs
deinterleaving to output a result of byte unit to the ATSC data byte
deinterleaver 902. And,
8-level decision value from the Viterbi decoder during decoding is fed back to
the equalizer
604. The ATSC data byte deinterleaver 902 deinterleaves the data of byte unit
outputted
from the Viterbi decoder/12-way deinterleaver 901.
[00121] Namely, the ATSC data byte deinterleaver 902 outputs the data of byte
unit
in a manner of performing deinterleaving on the output of the Viterbi
decoder/12-way
deinterleaver 901 according to a process reverse to that of the ATSC byte
interleaver in FIG.
3. The deinterleaved data can be divided into 188-byte packet units and can be
separated
into a normal data packet and an enhanced data packet. The data outputted from
the ATSC
data byte deinterleaver 902 is identically inputted to the ATSC RS decoder 903
and the
ATSC RS parity removing unit 951 of the enhanced data decoding unit 950.
[00122] The ATSC RS decoder 903 performs RS decoding on the data packet, which
is the output of the ATSC data byte deinterleaver 902, according to a process
reverse to that
of the ATSC RS coder in FIG. 3, and then outputs the result to the ATSC data
derandomizer
36
CA 02488327 2004-11-23
904.
[00123] The output of the ATSC data derandomizer 904 is finally outputted as
an
MPEG TPS #I. Since the enhanced data packets are encapsulated with null PID,
the
enhanced packets multiplexed in the output of the data derandomizer 904 can be
discarded,
and so there is no problem in receiving normal packets in the conventional AV
(audio/video) decoder.
[00124] The ATSC RS parity removing unit 95I of the enhanced data decoding
unit
950 removes an ATSC RS party portion from the output of the ATSC data byte
deinterleaver 902 and then outputs the result to the ATSC data derandomizer
952. Namely,
since the ATSC parity portion is not used in the enhanced data decoding, it
can be removed.
[00125] The ATSC data derandomizer 952 derandomizes the data of which ATSC
RS parity portion was removed in a process reverse to that of the ATSC
randomizer 302-1
in FIG. 3 and then outputs the result to the null-bit removing unit 953.
[00126] The E8-VSB data attribute generator 705 identifies whether the output
from
the ATSC data derandomizer 952 is a normal data byte or en enhanced data byte.
If it is the
byte for enhanced data, the E8-VSB data attribute generator 705 further
identifies whether
the enhanced data byte is a byte for the '/2 enhanced data or a byte for the
'/4 enhanced data.
The null-bit removing unit 953 removes the entire normal data bytes (including
MPEG
header bytes added to an enhanced data packet) and the null bits inserted to
the enhanced
data byte to reconfigure meaningful bytes and then outputs the reconfigured
bytes to the
37
CA 02488327 2004-11-23
enhanced data deinterleaver 954. In doing so, the VSB byte attribute
information outputted
from the main and enhanced mux packet processor 957 enables to identify
whether each
byte is for the normal data stream, the '/Z enhanced data byte, or the '/a
enhanced data byte.
[00127] First of all, in case of the normal data byte, the respective bits are
completely removed. In doing so, having the attribute of normal data, the MPEG
header
inserted in the '/z or '/4 enhanced data packet is removed as well. Meanwhile,
in case of the
enhanced data byte, reconfigurations are performed as shown in FIG. 13 and
FIG. 14.
Hence, the null-bit removing unit 953 ignores the normal data and outputs the
null-bit
removed'/2 and'/e enhanced data only.
[00128] Namely, in case of the '/z enhanced data, since one byte, as shown in
(b) of
FIG. 13, is expanded to 2 bytes by inserting the null bits in the E8-VSB
transmission system,
the insignificant bits (i.e., null bits) are removed in (b) of FIG. 13 to
reconfigure one
significant byte in (a) of FIG. 13. In case of the '/4 enhanced data, each
bit, as shown in (b)
of FIG. 14, is repeated and null-bits are inserted for a 4-byte expansion.
Hence, the
insignificant bits (i.e., repeated bits and null bits) are removed from (b) of
FIG. 14 to
reconfigure the four consecutive '/4 enhanced data bytes into one significant
byte shown in
(a) of FIG. 14.
[00129] The enhanced data deinterleaver 954 performs deinterleaving on
enhanced
data byte consisting of significant bits outputted from the null-bit removing
unit 953 in a
manner reverse to that of the enhanced data interleaver 505 in FIG. 6 and then
outputs the
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CA 02488327 2004-11-23
deinterleaved data to the enhanced RS decoder 955. The enhanced RS decoder 955
performs decoding on the deinterleaved data in a manner reverse to that of the
enhanced RS
coder 504 in FIG. 6 and then outputs the decoded data to the enhanced packet
demultiplexer
956.
[00130] The enhanced packet demultiplexer 956 separates the enhanced RS
decoded
data into a '/2 enhanced data packet of 164-byte unit and a '/4 enhanced data
packet of 164-
byte unit using the E8-VSB map information and field sync signal outputted
from the E8-
VSB map recovery 605 and then outputs them as MPEG TPS #2 and MPEG TPS #3,
respectively. The separation scheme is explained with reference to FIG. 15 and
a method of
generating the enhanced packet having the enhanced data attribute information
is explained
with reference to the enhanced packet generator in FIG. 12. Thus, by receiving
the E8-VSB
signal, it is able to receive the normal data MPEG TPS #1, the'/2 enhanced
data MPEG TPS
#2, and the '/4 enhanced data MPEG TPS #3.
[00131] Namely, the main and enhanced mux packet processor 801 in FIG. 10
performs the same operation of the main and enhanced mux packet processor 957
in FIG.
11. The corresponding detailed diagram of the main and enhanced mux packet
processor is
shown in FIG. 12.
[00132] In the present invention, the main and enhanced mux packet processors
are
provided to the E8-VSB data attribute generator 705 and the E8-VSB channel
decoder/demultiplexer 606, respectively. Alternatively, one main and enhanced
mux packet
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CA 02488327 2004-11-23
processor is provided to the present invention so that an output of the main
and enhanced
mux packet processor can be used in both the E8-VSB data attribute generator
705 and the
E8-VSB channel decoder/demultiplexer 606.
[00133] FIG. 12 is a detailed block diagram of the main and enhanced mux
packet
processor 801 or 957.
[00134] The main and enhanced mux packet processor generates attribute
information of E8-VSB data of byte unit using the E8-VSB map information of
the current
field decided by the current map deciding unit 703 of the E8-VSB map recovery
605 and
the field sync signal recovered by the frame sync recovery 704. The attribute
information
of E8-VSB data of byte unit provides information of whether the current byte
is the normal
data byte or the enhanced data byte. If the current byte is the enhanced VSB
byte, the
attribute information also provides information of whether the enhanced data
byte is the '/2
enhanced data byte coded at '/2 code rate or the '/4 enhanced data byte coded
at '/4 code rate.
[00135] For this, the main and enhanced mux packet processor includes an
enhanced
packet generator 101 l, a null enhanced RS codes 1012, an enhanced data
interleaves 1013, a
null-bit expander 1014, a null MPEG header inserter 1015, and a main and
enhanced packet
multiplexes 1016.
[00136] Namely, the enhanced packet generator 1011 generates an attribute
packet
having the attribute information of whether the enhanced data is the '/2
enhanced data or the
'/4 enhanced data. By the E8-VSB map information of the current field, the
distributions
CA 02488327 2004-11-23
and rates of the '/2 and '/4 enhanced data packets of the current field are
determined. In
accordance with the two distribution types, FIG. 15A and FIG. I SB show a case
that the
number of packets of the %2 enhanced data is eight and the number of packets
of the '/4
enhanced data is two. Namely, FIG. 15A shows an example that the '/z enhanced
data
packets and the '/4 enhanced data packets are separately grouped to be
multiplexed
(grouping multiplexing) and FIG. 15B shows an example that the '/z enhanced
data packets
and the '/4 enhanced data packets are alternately multiplexed one by one
(alternate
multiplexing).
[00137] In doing so, the enhanced packet generator 1011 generates an attribute
signal for whether each enhanced packet has the attribute of '/z or '/4 rather
than a signal
including significant data. The attribute signal enables to output an
attribute of E8-VSB
data byte via the null enhanced RS codes 1012, enhanced data interleaves 1013,
null bit
expander 1014, null MPEG header inserter 1015, and main and enhanced packet
multiplexes 1016.
[00138] Namely, an attribute packet of 164 bytes having the attribute
information of
the enhanced data outputted from the enhanced packet generator 1011 is
inputted to the null
enhanced RS codes 1012. The null enhanced RS codes 1012 adds a parity of 20
bytes to the
received attribute packet of 164 bytes to output an attribute packet of 184
bytes. In doing so,
the parity added to the parity area is for justification. Hence, the attribute
of each packet is
copied as many as a parity amount for expansion. Namely, although the parity
generated
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CA 02488327 2004-11-23
from performing substantial enhanced RS coding is added in a normal data path,
the
expansion is performed by the null enhanced RS codes 1012 in a manner of
copying the
attribute of each packet to the parity area as many as the parity amount.
[00139] An output of the null enhanced RS codes 1012 is inputted to the
enhanced
data interleaves 1013 for interleaving and the interleaved output is outputted
to the null bit
expander 1014. The interleaving is achieved in the same manner of the enhanced
data
interleaves 505.
[00140] The null bit expander 1014, as shown in FIG. 13 or FIG. 14, expands
the
interleaved byte outputted from the enhanced data interleaves 1013 to fit the
'/2 or '/4
enhanced data. Namely, if the byte from the enhanced data interleaves 1013 is
the byte
having the '/Z attribute information and has the configuration shown in (a) of
FIG. 13, the
null bit expander 1014, as shown in (b) of FIG. 13, inserts null bits in the
byte to expand to
two bytes. If the byte from the enhanced data interleaves 1013 is the byte
having the '/4
attribute information and has the configuration shown in (a) of FIG. 14, the
null bit
expander 1014 performs bit repetition and null bit insertion to expand the
byte to 4 bytes.
The null bit expander 1014 then outputs the expanded bytes to the null MPEG
header
inserter 1015. In doing so, since the expanded byte means the attribute of the
enhanced data,
values of b7 to b0 are identical to each other unlike the null bit expander of
the transmitter.
[00141] The null MPEG header inserter 1015 adds a value, which indicates the
normal data byte corresponding to an MPEG header, in front of each 184 bytes
outputted
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CA 02488327 2004-11-23
from the null bit expander 1014 and then outputs the corresponding result to
the main and
enhanced packet multiplexes 1016. The main and enhanced packet multiplexes
1016, which
outputs packets by 188-byte packet unit, multiplexes the normal data packets
and the
enhanced data packets to output. In doing so, the main and enhanced packet
multiplexes
1016 seeks the number H of the %2 enhanced data packets of 188-byte unit and
the number
Q of the'/4 enhanced data packets of 188-byte unit from the E8-VSB map
information based
on the field sync signal outputted from the E8-VSB map recovery 605 and then
finds the
number 2P of packets of 188-byte unit allocated to the enhanced data per one
VSB field
(2P=2H+4P).
[00142] The main and enhanced packet multiplexes 1016 multiplexes the normal
data packets and the enhanced data packets using a multiplexing rule based on
the
distribution method selected in the E8-VSB map information. For example, if a
pattern
distribution method is selected, the multiplexing rule shown in FIG. 16A may
be used. In
this rule, positions of the enhanced data packet in a data field are assigned
to every fourth
segment starting from at least one predetermined start position (segment
position 0, 2, 1,
and/or 3) within the data field.
[00143] On the other hand, if an even (uniform) distribution method is
selected, the
multiplexing rule shown in FIG. 16B may be used. "s" shown in both rules
denotes a
packet (or segment before ATSC byte interleaving) position for an enhanced
data packet
with respect to a field synchronizing signal within the data field. By
outputting a signal
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CA 02488327 2004-11-23
indicating the normal data byte in case of a normal data packet or outputting
a signal from
the null MPEG header inserter 1015 in case of an enhanced data packet, the
final E8-VSB
data byte attribute is outputted.
[00144] As mentioned in the foregoing description of the digital E8-VSB
reception
system and E8-VSB data demultiplexing method according to the present
invention, the
enhanced data are coded at '/2 code rate and '/4 code rate in the new E8-VSB
transmission
system compatible with the conventional ATSC 8VSB system, respectively. The
'/2 and '/4
enhanced data are multiplexed by 164-byte packet unit according to the
previously
determined multiplexing format and further pre-processed to output as the
format of the
MPEG transport packet. And, the pre-processed enhanced data and the main data
are
multiplexed again by 188-byte packet unit according to the previously
determined
multiplexing format. In such a case, the E8-VSB reception system according to
the present
invention enables to completely receive both of the ATSC 8VSB signal and the
E8-VSB
signal.
[00145] Moreover, the E8-VSB map information, which was inserted in the field
sync section in the E8-VSB transmission system to be transmitted, is extracted
to generate
the information indicating the attributes of the respective E8-VSB data. The
normal data, '/z
enhanced data, and '/4 enhanced data are separated from each other to be
decoded in the
channel decoder. And, the E8-VSB data symbol attribute is used in channel
equalization.
Therefore, the present invention improves the performance of the equalizer,
thereby
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CA 02488327 2004-11-23
enabling to enhance the performance of the E8-VSB reception system.
[00146] It will be apparent to those skilled in the art that various
modifications and
variations can be made in the present invention. Thus, it is intended that the
present
invention covers the modifications and variations of this invention provided
they come
within the scope of the appended claims and their equivalents.
