Note: Descriptions are shown in the official language in which they were submitted.
CA 02565736 2007-04-24
7 9 63 6-5
Description
DIGITAL BROADCASTING TRANSMISSION AND/OR
RECEPTION SYSTEM TO IMPROVE RECEIVING
PERFORMANCE AND SIGNAL PROCESSING METHOD
THEREOF
Technical Field
[1] The present general inventive concept relates to a digital broadcasting
transmission
and/or reception system and a signal processing method thereof, and more
particularly,
to a digital broadcasting transmission and/or reception system and a signal
processing
method thereof capable of improving reception performance of a reception
system by
inserting and transmitting a known sequence into a VSB (Vestigial Side Bands)
data
stream.
Background Art
[2] Generally, an ATSC (Advanced Television Systems Committee) VSB mode,
which is the U.S. terrestrial digital broadcasting system, is a single carrier
method, and
a field sync is used in a unit of 312 segments.
[3] FIG. 1 is a block diagram for displaying a transceiver including a
digital
broadcasting transmitter and a digital broadcasting receiver according to an
ATSC
DTV standard as a general U.S. terrestrial digital broadcasting system.
[4] Referring to FIG. 1, the digital broadcasting transmitter has a
randomizer 110 for
randomizing an MPEG-2 transport stream (TS), a Reed-Solomon (hereafter
referred to
as 'RS') encoder 120 for adding Reed-Solomon parity bytes into the MPEG-2
transport
stream to correct a bit error caused by a channel characteristic in a
transporting
process, an interleaver 130 for interleaving the RS encoded data according to
a certain
pattern, and a Trellis encoder for performing trellis encoding by a 2/3-rate
to the in-
terleaved data and 8-level symbol mapping to perform error correcting coding
for the
MPEG-2 transport stream.
[5] The digital broadcasting transmitter also includes a MUX 150 for
inserting a
segment sync and a field sync to the error correction coded data, and a
Modulator/RF
up-converter 160 for inserting a pilot tone after adding a certain DC value in
a data
symbol that the segment sync and the field sync are inserted, and for
performing VSB
modulation and up-converting to and transmitting an RF channel band signal.
[6] Therefore, the digital broadcasting transmitter randomizes the MPEG-2
transport
stream, outer-codes the randomized data through the RS encoder 120 which is an
outer
coder, and distributes the coded data through the interleaver 130. Also, the
digital
broadcasting transmitter inner-codes the interleaved data through Trellis
encoder 140
2
WO 2005/109877 PCT/KR2005/001313
by a 12 symbol rate, maps the inner coded data by an 8 symbol rate, and then
inserts
the field sync, the segment sync, and the pilot tone for VSB modulation, and
converts
to and transmits the RF signal.
171 Meanwhile, the digital broadcasting receiver includes a tuner/IF 210
for converting
a received RF signal to a baseband signal, and a demodulator 220 for
synchronizing
and demodulating the converted baseband signal, an equalizer 230 for
compensating
the demodulated signal for channel distortion caused by a multipath, a Trellis
decoder
240 for applying error correction and decoding with respect to the equalized
signal, a
deinterleaver 250 for rearranging the dispersed data by the interleaver 130 of
the
digital broadcasting transmitter, an RS decoder 260 for correcting errors, a
de-
randomizer 270 for outputting the MPEG-2 transmission stream by derandomizing
the
corrected data through RS decoder 260.
[81 Hence, an operation sequence of the digital broadcasting receiver of
FIG. 1 is a
reverse order of the digital broadcasting transmitter, that is, down-
converting the RF
signal to the baseband signal, demodulating and equalizing the down-converted
signal,
performing channel decoding, and restoring the original signal.
191 FIG. 2 shows a VSB data frame interleaved with a segment sync signal
and a field
sync signal for the U.S. digital broadcasting (8-VSB) system. Each data frame
consists
of two data fields, and each field contains a 1 field sync segment and a 312
data
segment. In the VSB data frame, the segment is equivalent to one MPEG-2
packet, and
can have a 4-symbol segment sync and 828 data symbols.
[10] In FIG. 2, the segment sync signal and field sync signal for sync
signals are used
for synchronization and equalization at the digital broadcasting receiver.
That is, the
field sync signal and segment sync signal are data between the digital
broadcasting
transmitter and receiver to be used as reference signals in equalization by
the receiver.
[11] The VSB mode of the U.S. terrestrial digital broadcasting system
depicted in FIG.
1 adopts a single carrier method, which has a weakness in multipath fading
channel en-
vironments with Doppler. Therefore, performance of the digital broadcasting
receiver
depends on a capacity of the equalizer for eliminating such multipath.
[12] However, the existing transmitting frame of FIG. 2 has a weakness in
degerading
an equalization performance due to a low frequency in appearance, since the
field
sync, that is a reference signal of an equalizer, appears once every 313
segments.
[13] That is, it is difficult to estimate channels and to equalize the
received signal by
eliminating the multipath using an existing equalizer and such small data
described
above. Due to this, the conventional digital broadcasting receiver has a
problem of
reception performance deterioration in poor channel environment, particularly
in
Doppler fading channel environment.
CA 02565736 2006-11-03
CD, 02565736 2009-12-21
79636-5
3
Disclosure of Invention
Technical Problem
[14] The present general inventive concept provides a
digital broadcasting transmission and/or reception system
and a signal-processing method thereof capable of generating
and transmitting a transmission signal to which known data
is added at a digital broadcasting transmitter and of
detecting the transmission signal at a digital broadcasting
receiver, so as to improve the reception capacity of the
digital broadcasting receiver.
[15] Additional aspects and advantages of the present
general inventive concept will be set forth in part in the
description which follows and, in part, will be obvious from
the description, or may be learned by practice of the
general inventive concept.
Technical Solution
[16] The foregoing and/or other aspects and advantages
of the present inventive concept may be achieved by
providing a digital broadcasting transmitter comprising a
randomizer to input and randomize data streams including one
or more segments with at least one segment having one or
more null packets, a null packet exchanger to create known
data having a predetermined pattern and to replace the null
packets at positions of the one or more segments having the
null packets of the randomized data streams to insert the
known data, an encoder to encode the data streams to which
the known data is inserted, and a modulation/RF unit to
modulate, RF-convert, and transmit the encoded data streams.
[17] The data streams may include information about the
position at which the known data is inserted.
CA 02565736 2009-12-21
79636-5
4
[18] The encoder may include a first RS (Reed Solomon)
encoder to add a parity of predetermined bytes to the data
streams in which the known data is inserted in order to
correct errors occurring by channels, an interleaver to
apply data interleaving in a predetermined pattern with
respect to the data streams to which the parity is added,
and a Trellis encoder to perform a Trellis encoding of the
interleaved data stream.
[19] The Trellis encoder may comprise a memory element
for the Trellis-encoding operation, initializes the memory
element at the position where the known data is inserted,
and applies the Trellis encoding to the known data.
[20] The digital broadcasting transmitter may further
comprise a packet buffer to input and temporarily store the
data streams corresponding to the position where the memory
element of the Trellis-encoder is initialized from the first
RS encoder.
[21] The packet buffer may receive from the Trellis
encoder the data streams changed according to the
initialization of the memory element and may update the
stored data streams.
[22] The digital broadcasting transmitter may further
comprise a second RS encoder to apply the RS encoding to the
encoded known data input from the packet buffer to create
and output a changed parity to the Trellis encoder, to
replace the parity added by the first RS encoder, and to
apply the Trellis encoding to the replaced parity.
[23] The modulation/RF unit modulates the encoded data
in a Vestigial Side Bands (VSB) modulation method.
CD, 02565736 2009-12-21
79636-5
[24] The foregoing and/or other aspects and advantages
of the present general inventive concept may also be
achieved by providing a signal-processing method of a
digital broadcasting transmission system, the method
5 comprising inputting and randomizing data streams including
one or more segments having at least one segment having one
or more null packets, creating known data having a
predetermined pattern and replacing the null packets at
positions of the segments having the null packets of the
randomized data streams to insert the known data, encoding
the data streams to which the known data is inserted, and
modulating, RF-converting, and transmitting the encoded data
streams.
[25] The encoding operation may include adding a parity
of predetermined bytes to the data streams in which the
known data is inserted in order to correct errors occurring
by channels, applying data interleaving in a predetermined
pattern to the data streams to which the parity is added,
and performing a Trellis encoding of the interleaved data
stream.
[26] The Trellis encoding operation may comprise
initializing a memory element and performing the Trellis-
encoding operation at the position at which the known data
is inserted.
[27] The signal-processing method may further comprise
inputting and temporarily storing the data streams
corresponding to the position where the memory element for
the Trellis-encoding operation is initialized from the first
RS encoding operation, and inputting and updating the stored
data streams as the data streams changed according to the
initialization of the memory element in the Trellis encoding
operation.
CD, 02565736 2009-12-21
79636-5
5a
[28] The signal-processing method may further comprise
a second RS encoding operation of applying the RS encoding
to the known data encoded according to the initialization of
the memory element and creating a changed parity, wherein
the Trellis-encoding operation is repeated to replace the
parity added in the first RS encoding operation with the
changed parity, add and apply the Trellis encoding to the
changed parity.
[29] The modulation/RF operation may comprise
modulating the encoded data in a Vestigial Side Bands (VSB)
method.
[30] The foregoing and/or other aspects and advantages
of the present general inventive concept may also be
achieved by providing a digital broadcasting receiver
comprising a tuner to receive a signal from a digital
broadcast transmitter and to convert the received signal to
a baseband signal, the signal that is encoded by inserting
known data with respect to a data stream to which null
packets are inserted at a specified position at intervals, a
demodulator to demodulate the baseband signal, a known data
detector to detect the known data from the demodulated
signal, and an equalizer to equalize the signal demodulated
using the detected known data.
[31] The known data may have a predetermined pattern.
[32] The known data detector may detect and output to
the equalizer the known data using information of the
positions at which the known data included in the received
signal is inserted.
[33] The known data detector may comprise outputting
the detected known data to the demodulator, and the
demodulator may perform demodulating using the known data.
CA 02565736 2009-12-21
79636-5
5b
[34] In the meantime, the foregoing and/or other
aspects and advantages of the present general inventive
concept may also be achieved by providing a signal-
processing method of a digital broadcasting reception
system, the signal-processing method comprising receiving a
signal from a digital broadcast transmitter and converting
the received signal to a baseband signal, the signal that is
encoded by inserting known data with respect to a data
stream to which null packets are inserted at a specified
position at intervals, demodulating the baseband signal,
detecting the known data from the demodulated signal, and
equalizing the signal demodulated using the detected known
data.
[35] The known data may have a predetermined pattern.
[36] The known data-detecting operation may comprise
detecting the known data using information of the positions
at which the known data included in the received signal is
inserted.
[37] The known data-detecting operation may further
comprise outputting the detected known data to the
demodulation operation, and the demodulation operation
comprises performing demodulation using the known data.
[37a] According to one broad aspect of the invention a
digital broadcast receiver configured to receive a signal
from a digital transmitter, wherein the digital transmitter
comprises a known data exchanger inserting known data at a
certain position in data, an interleaver interleaving the
data including the known data, a trellis encoder trellis
encoding the interleaved data to an 8-level symbol at a rate
of 2/3, and initializing a memory of the trellis encoder to
a predetermined value in a predetermined position of the
interleaved known data, and a modulator performing a VSB
CA 02565736 2009-12-21
79636-5
5c
modulation of the trellis encoded data, the digital
broadcast receiver comprising: a demodulator performing a
VSB demodulation of the received, modulated signal, the
signal having the trellis encoded symbol corresponding to
the known data, the known data being processed by the
initialized trellis encoder of the transmitter; and an
equalizer removing an interference of the demodulated signal
according to the trellis encoded symbol corresponding to the
known data, wherein the known data is a predefined sequence
known between the digital transmitter and the digital ,
broadcast receiver.
[37b]
According to another broad aspect of the invention
a digital broadcast receiver configured to receive a signal
from a digital transmitter, wherein the digital transmitter
comprises a known data exchanger inserting known data at a
certain position in data, the known data being a predefined
sequence known between the digital transmitter and the
digital broadcast receiver, an interleaver interleaving the
data including the known data, a trellis encoder trellis
encoding the interleaved data to an 8-level symbol at a rate
of 2/3, and initializing a memory of the trellis encoder to
a predetermined value in a predetermined position of the
interleaved known data, and a modulator performing a VSB
modulation of the trellis encoded data, the digital
broadcast receiver comprising: a tuner configured to receive
the signal transmitted by the digital transmitter, the =
signal having the trellis encoded symbol corresponding to
the known data, the known data being processed by the
initialized trellis encoder of the transmitter; a
demodulator performing a VSB demodulation of the received
signal, which was modulated by the modulator of the
transmitter; and an equalizer removing an interference of
the demodulated signal according to the trellis encoded
CD, 02565736 2009-12-21
79636-5
5d
symbol corresponding to the known data by compensating for a
channel distortion of the demodulated signal due to a multi-
path of a channel.
[37c] According to still another broad aspect of the
invention a signal processing method for a digital broadcast
receiver receiving a signal from a digital transmitter that
inserts known data at a certain position in data, the known
data being a predefined sequence known between the digital
transmitter and the digital broadcast receiver, interleaves
the data including the known data, and initializes a memory
of a trellis encoder to a predetermined value in a
predetermined position of the interleaved known data to
trellis encode the interleaved data to an 8-level symbol at
a rate of 2/3, the signal processing method comprising:
receiving the signal transmitted by the digital transmitter,
the signal having the trellis encoded symbol corresponding
to the known data, the known data being processed by the
initialized trellis encoder of the transmitter; performing a
VSB demodulation of the received signal, which was modulated
by the modulator of the transmitter; and removing an
interference of the demodulated signal according to the
trellis encoded symbol corresponding to the known data by
compensating for a channel distortion of the demodulated
signal due to a multi-path of a channel.
Advantageous Effects
[38] According to the embodiment of the present general
inventive concept, the digital broadcasting transmitter
creates and inserts the null packets into an MPEG-2
transmission stream packet, replaces the inserted null
packets with the known data and sends the known data, and
the digital broadcasting receiver detects the known data
from a received signal from the digital broadcasting
CA 02565736 2009-12-21
79636-5
5e
transmitter and uses the known data for the synchronization
and equalization so that its digital broadcasting reception
performance can be improved on poor multipath channel.
[39]
Further, the present general inventive concept can
improve an operational performance of an equalizer and
improve digital broadcasting reception performance
6
WO 2005/109877 PCT/KR2005/001313
by properly controlling the frequency and quantity of the known data for sync
and
equalization of a receiver.
Description of Drawings
[40] These and/or other aspects and advantages of the present general
inventive concept
will become apparent and more readily appreciated from the following
description of
the embodiments, taken in conjunction with the accompanying drawings of which:
[41] FIG. 1 is a block diagram showing a transmission/reception system for
a general
US digital broadcasting system;
[42] FIG. 2 is a view showing an ATSC VSB data frame structure;
[43] FIG. 3 is a block diagram showing a digital broadcasting transmission
and/or
reception system according to an embodiment of the present general inventive
concept;
[44] FIG. 4 is a view showing a format of MPEG-2 packet data according to
an
embodiment of the present general inventive concept;
[45] FIG. 5 is a view showing a format of data to which data interleaving
is applied;
[46] FIG. 6 is a view showing a format of data to which Trellis encoding is
applied;
[47] FIG. 7 is a flowchart showing operations of a digital broadcasting
transmitter
according to an embodiment of the present general inventive concept; and
[48] FIG. 8 is a flowchart showing operations of a digital broadcasting
receiver
according to an embodiment of the present general inventive concept.
Best Mode
[49] Reference will now be made in detail to the embodiments of the present
general
inventive concept, examples of which are illustrated in the accompanying
drawings,
wherein like reference numerals refer to the like elements throughout. The em-
bodiments are described below in order to explain the present general
inventive
concept while referring to the figures.
[50] FIG. 3 is a block diagram showing a digital broadcasting transmission
and/or
reception system according to an embodiment of the present general inventive
concept.
The digital broadcasting transmission and/or reception system may have a
digital
broadcasting transmitter and a digital broadcasting receiver.
[51] Referring to FIG. 3, the digital broadcasting transmitter includes a
randomizer 310,
a null packet exchanger 315, a first RS encoder 320, a packet buffer 325, an
interleaver
330, a second RS encoder 335, a Trellis encoder 340, a multiplexer 350, and a
modulation and RF unit 360.
[52] The randomizer 310 randomizes inputted MPEG-2 transmission stream data
in
order to improve the usage of an allocated channel space.
[53] The stream data input to the randomizer 310 has a null packet of a
segment unit
that does not include ordinary data within a segment in a predetermined
interval, which
CA 02565736 2006-11-03
7
WO 2005/109877 PCT/KR2005/001313
will be described in detail later.
[54] The null packet exchanger 315 creates a specific sequence
(hereinafter, referred to
as 'known data') having a predetermined pattern defined beforehand between a
transmitter and a receiver, so that the null packet is replaced with the known
data in the
segment corresponding to the null packet among randomized data streams.
[55] The known data is used for synchronization and equalization at the
receiver since
its pattern is distinguished from general transmission and reception payloads
so that the
known data can be easily detected from payload data.
[56] The first RS encoder 320 replaces the null packet with the known data
by the null
packet exchanger 315 in order to correct errors caused by channels, and
applies the RS
encoding to an outputted data stream, and adds a parity of predetermined
bytes.
[57] The interleaver 330 performs data interleaving in a prescribed pattern
with respect
to the parity-added packet output from the first RS encoder 320.
[58] The Trellis encoder 340 converts to a symbol the data outputted from
Interleaver
330, and performs 8-level symbol mapping through the Trellis encoding of a 2/3
ratio.
The Trellis encoder 340 initializes a value temporarily stored in its memory
device in a
beginning point of the known data, to a specific value, and performs the
Trellis
encoding to the known data. For example, the value stored in the memory device
is
initialized to a '00' state.
[59] The packet buffer 325 inputs and temporarily stores the known data
from data
stream outputted in the first RS encoder 320, inputs the known data changed
according
to initialization if the known data is changed according to the initialization
of the
memory device of the Trellis encoder 340, and temporarily stores the changed
known
data replacing the temporarily stored known data before the change, and inputs
the
changed known data to the second RS encoder 335 for parity re-creation.
[60] The second RS encoder 335 receives the known data changed according to
the ini-
tialization, and re-creates and inputs the parity according to the changed
known data
into the Trellis encoder 340 so as to replace the original parity with a newly
created
parity, and applies the Trellis encoding to the changed (recreated or input)
parity.
[61] Therefore, the packet data output from the Trellis encoder 340 to the
MUX 350 has
the known data changed according to the initialization of the memory device of
the
Trellis encoder 340 and the parity-added data format according to the
initialization and
the RS encoding.
[62] The MUX 350 inserts a segment sync signal by a segment unit, as shown
in the
data format of FIG. 2, to data converted to a symbol by the Trellis encoder
340, inserts
a field sync signal by a field unit, and inserts a pilot signal on an edge
part of a low
frequency band on a frequency spectrum by adding a predetermined DC value to a
data
signal of a predetermined level.
CA 02565736 2006-11-03
8
WO 2005/109877 PCT/KR2005/001313
[63] The modulation/RF unit 360 pulse-shapes and performs VSB modulation
with
respect to the data signal into which the pilot signal is inserted, wherein
the VSB
modulation amplitude-converts the data signal by putting the signal on an
intermediate
frequency (IF) carrier and the like, and RF-converts, amplifies, and sends the
modulated signal in a predetermined band through an allocated channel.
[64] In the meantime, the digital broadcasting receiver of FIG. 3 includes
a tuner 410,
demodulator 420, equalizer 430, a Trellis decoder 440, a de-interleaver 450,
an RS
decoder (460), a derandomizer 470 and a known data detector 480, and decodes a
received signal by performing reverse operations of the digital broadcasting
transmitter
of FIG. 3.
[65] The tuner 410 tunes the received signal and converts the tuned signal
of a tuned
band to a baseband signal.
[66] The demodulator 420 detects a sync signal according to the pilot
signal and the
sync signal inserted in a signal of the baseband signal and performs
demodulation.
[67] Further, the equalizer 430 removes interference between received
symbols by com-
pensating for channel distortion caused by a multipath of channels from a
decoded
signal. That is, the signal of the baseband signal may be at least one of
signals
transmitted to the digital broadcasting receiver from the digital broadcasting
transmitter through at least one of a plurality of paths, and the multipath of
the
channels may comprise a first channel and a second channel corresponding to
the
plurality of paths. The respective symbols of the signals are different from
each other
due to the different paths or channels through which the signals are
transmitted.
Therefore, the equalizer 430 can remove the interference occurring between the
received symbols of the first and second channels or the plurality of paths,
according to
the detected known data.
[68] The Trellis decoder 440 performs error correction, decodes the error-
corrected
symbols, and outputs symbol data.
[69] The decoded data re-sorts distributed data by the Interleaver 330 of
the digital
broadcasting transmitter through the deinterleaver 450.
[70] The RS decoder 460 corrects errors of the deinterleaved data, and the
data
corrected through the RS decoder 460 is derandomized through the derandomizer
470
so that the data of MPEG-2 transmission stream is restored.
[71] In the meantime, the known data detector 480 detects the known data
from the
decoded data, and provides the known data for sync detection of the
demodulator 420
and channel distortion compensation of the equalizer 430.
[72] FIG. 4 is a view showing an MPEG-2 packet data format according to an
embodiment of the present general inventive concept.
[73] Referring to FIG. 4, a data frame of a general MPEG-2 data stream has
a plurality
CA 02565736 2006-11-03
9
WO 2005/109877 PCT/KR2005/001313
of segments each having a head part, such as a 3-byte header having a first
byte as a
sync signal and a PID (Packet Identity), and general payload data A intended
to be
transmitted. The general payload data of the segment may include a video
signal and
an audio signal.
[74] According to the embodiment of the present general inventive concept,
at least one
of the plurality of segments has a null packet, which does not include the
general
payload data, in a predetermined interval except for the header part. The null
packet is
disposed between a first number of segments and a second number of segments,
and
the first number may be the same as the second number. In this case, the null
packet is
periodically formed in the data stream.
[75] That is, the segment having the null packet does not include separate
information
intended to be transmitted except for the header part including information
about a null
packet position.
[76] On the other hand, the embodiment of the present general inventive
concept inserts
one null packet segment in every predetermined interval for the convenience of
ex-
planation, but the frequency and number of null packet segments can be
adjusted
according to a data transmission rate, channel environment, and so on.
[77] FIG. 5 is a view showing a data format of a data frame to which data
interleaving is
applied.
[78] Referring to FIGS. 3 through 5, the interleaver 330 disturbs the order
of the data
stream to distribute data in a time axis so that a transmission signal becomes
strong in
interference.
[79] Such a data distribution method of the interleaver 330 shows that the
null data
contained in the same segment regularly and in order appears once every 52
bytes in a
width that is equal crosswise to appear sequentially and regularly once every
52 byte.
[80] FIG. 6 is a view showing a format of data to which the Trellis
encoding is applied.
[81] Referring to FIGS. 3-6, the Trellis encoder 340 encodes one byte of
data outputted
from the interleaver 330 into four 8-level symbols.
[82] Each known data byte appearing every 52 bytes is encoded to 4 symbols.
[83] Hereinafter, a symbol created from the Trellis encoding with respect
to the known
data byte is referred to as a known symbol.
[84] Therefore, 4 known symbols appears every 208 symbols if the Trellis
encoding is
performed
[85] That is, the known symbol is regularly inserted in a general data
stream in a pre-
determined interval, so that the known symbol can be easily detected from the
general
data stream.
[86] FIG. 7 is a flowchart showing operations of a digital broadcasting
transmitter
according to an embodiment of the present general inventive concept.
CA 02565736 2006-11-03
CA 02565736 2007-04-24
7 9 63 6 ¨ 5
[87] Referring to FIGS. 3-7, the randomizer 310 receives and randomizes the
MPEG-2
transmission stream including the plurality of segments including the at least
one
segment having a null packet that does not include ordinary data (S510).
[88] The data inputted to the randomizer 310 has the data format as shown
in FIG. 4.
[89] In FIG. 4, of the MPEG-2 packets according to the present invention,
the at least
one segment having the null packet includes the header part having a first
byte as the
sync signal and a 3-byte PID (Packet Identity), and does not include the
general
payload data.
[90] Further, the null packet exchanger 315 creates a packet having the
known data, and
inserts the packet having the known data at the position of the null packet
included in
the data randomized in the randomizer 310 (S520).
[91] The known data has a predetermined pattern as the data known between a
transmitter and a receiver so that the known data can be distinguished from
the general
data and easily detected.
[92] Further, the error correction encoding is applied to a transmission
stream into
which the known data output from the null packet exchanger 315 is inserted, so
that the
errors occurring by a channel are corrected (S530).
[93] For the error correction encoding, the first RS encoder 320 adds a
parity of pre-
determined bytes by performing the RS encoding, and interleaver 330 performs
the
data interleaving in a predetermined pattern, the Trellis encoder 340 converts
the in-
terleaved data to a symbol and performs a 8-level symbol mapping through the
Trellis
encoding of a 2/3 ratio.
[94] In the meantime, the packet buffer 325 inputs and temporarily stores
data output
from the first RS encoder 320, and, if the known data is trellis-encoded in
the Trellis
encoder 340 according to initialization, the packet butter 325 inputs from the
Trellis
encoder 340 the known data changed as initialized, updates the known data
temporarily stored before change, and temporarily stores the changed known
data.
[95] The changed known data input to the packet buffer 325 is input to the
second RS
encoder 335 for parity recreation
[96] The second RS encoder 335 applies the RS encoding to the changed known
data.to
create a changed parity, and sends the created parity to the Trellis encoder
340.
[97] Accordingly, the Trellis encoder 340 replaces a previous parity with
the changed
parity input from the second RS encoder 335, applies the Trellis encoding to
the
changed parity, and outputs the Trellis-encoded parity according to the output
symbol
data already Trellis-encoded.
[98] Therefore, the packet data outputted to the MUX 350 in the Trellis
encoder 340 is
the data Trellis-encoded to the 8-level symbol with respect to the known data
changed
according to the initialization of the memory device of the Trellis encoder
340 and the
11
WO 2005/109877 PCT/KR2005/001313
packet data parity-added by the RS encoding.
[99] Further, a segment sync signal is inserted to each segment of the
symbol data, a
field sync signal is inserted to each field, and a pilot signal is inserted on
a frequency
spectrum (S540).
[100] Further, the modulation/RF unit 360 performs the VSB modulation such
as the
pulse shaping of a signal into which a pilot signal is inserted, the amplitude
modulation
of an Intermediate Frequency carrier, and so on, RF-converts and amplifies the
modulated signal, and transmits the amplified signal through an allocated
channel
(S550).
[101] As stated above, the digital broadcasting transmitter creates and
inserts null packets
into the MPEG-2 transmission stream, replaces the inserted null packets with
the
known data, and sends the known data, and the digital broadcasting receiver
detects a
nd uses the known data so as to improve its reception performance such as the
sync ac-
quisition and equalization performance.
Mode for Invention
[102]
Industrial Applicability
[103] The present general inventive concept relates to a digital
broadcasting transmission
and/or reception system and a signal processing method thereof, and more
particularly,
to a digital broadcasting transmission and/or reception system and a signal
processing
method thereof capable of improving reception performance of a reception
system by
inserting and transmitting a known sequence into a VSB (Vestigial Side Bands)
data
strea.
Sequence List Text
[104]
CA 02565736 2006-11-03
