Channel equalizer and method of processing broadcast signal in DTV receiving system

• US 8,204,137 B2
• Filed: 09/22/2011
• Issued: 06/19/2012
• Est. Priority Date: 02/10/2006
• Status: Expired due to Fees

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Kim, Byoung Gill, Choi, In Hwan, Kang, Kyung Won, Kwak, Kook Yeon, Kim, Woo Chan
• Primary Examiner(s): Puente, Eva
• Assistant Examiner(s): HUGHES, EBONI N
• Application Number:
  US13/241,181
• Publication Number:
  US 20120069913A1
• Time in Patent Office: 271 Days
• Field of Search: 375/229, 375/231, 375/232, 375/240.01, 375/240.18, 37524025-24027, 348607-614, 348/723
• US Class Current: 375/240.27
• CPC Class Codes: H03M 13/2792 Interleaver wherein interleaving is performed jointly with another technique such as puncturing, multiplexing or routing
• CPC Class Codes: H03M 13/2906 using block codes H03M13/2957 takes precedence
• CPC Class Codes: H03M 13/2936 comprising an outer Reed-Solomon code and an inner convolutional code
• CPC Class Codes: H03M 13/6538 ATSC VBS systems
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 12/189 in combination with wireless systems selective distribution or broadcast in wireless communication networks H04W4/06
• CPC Class Codes: H04L 25/0212 of impulse response
• CPC Class Codes: H04L 25/0232 by interpolation between sounding signals
• CPC Class Codes: H04L 25/03159 operating in the frequency domain H04L25/03165, H04L25/03178 take precedence
• CPC Class Codes: H04N 19/89 involving methods or arrangements for detection of transmission errors at the decoder
• CPC Class Codes: H04N 19/895 in combination with error concealment
• CPC Class Codes: H04N 21/236 Assembling of a multiplex stream, e.g. transport stream, by combining a video stream with other content or additional data, e.g. inserting a URL [Uniform Resource Locator] into a video stream, multiplexing software data into a video stream; Remultiplexing of multiplex streams; Insertion of stuffing bits into the multiplex stream, e.g. to obtain a constant bit-rate; Assembling of a packetised elementary stream multiplexing of data packets for data networks, e.g. RTP/UDP H04L65/00
• CPC Class Codes: H04N 21/23614 Multiplexing of additional data and video streams arrangements for simultaneous broadcast of plural pieces of information H04H20/28
• CPC Class Codes: H04N 21/631 Multimode Transmission, e.g. transmitting basic layers and enhancement layers of the content over different transmission paths or transmitting with different error corrections, different keys or with different transmission protocols
• CPC Class Codes: H04N 5/21 Circuitry for suppressing or minimising disturbance, e.g. moiré or halo
• CPC Class Codes: H04N 5/38 Transmitter circuitry for the transmission of television signals according to analogue transmission standards H04N5/14 takes precedence
• CPC Class Codes: H04N 5/40 Modulation circuits
• CPC Class Codes: H04N 5/455 Demodulation-circuits
• CPC Class Codes: H04N 7/12 Systems in which the television signal is transmitted via one channel or a plurality of parallel channels, the bandwidth of each channel being less than the bandwidth of the television signal H04N7/24 takes precedence

Abstract

A channel equalizer includes a first transformer, an estimator, an average calculator, a second transformer, a coefficient calculator, a compensator, and a third transformer. The first transformer converts normal data into frequency domain data, where a known data sequence is periodically repeated in the normal data. The estimator estimates channel impulse responses (CIR) during known data intervals adjacent to each normal data block. The average calculator calculates an average value of the CIRs. The second transformer converts the average value into frequency domain data. The coefficient calculator calculates equalization coefficients using the average value, and the compensator compensates channel distortion of each normal data block using the coefficients. The third transformer converts the compensated data block into time domain data.

Claims

1. A method of processing a digital broadcast signal for transmitting the digital broadcast signal, the method comprising:

first randomizing enhanced service data;

Reed-Solomon (RS) encoding the first randomized enhanced service data for each column of at least one RS frame payload and adding Cyclic Redundancy Check (CRC) checksum byte at right end of each row of the at least one RS frame payload to build at least one RS frame;

forming data groups including the enhanced service data in the built at least one RS frame and a plurality of known data sequences;

formatting enhanced service data packets including the enhanced service data and the plurality of known data sequences in the data groups;

multiplexing the enhanced service data packets with main service data packets including main service data;

performing second randomizing for the main service data in the multiplexed enhanced and main service data packets; and

trellis-encoding the enhanced service data and randomized main service data at a trellis encoder,

wherein a data group having the trellis-encoded enhanced service data and main service data includes first segments, second segments and third segments, the second segments being positioned between the first and third segments, the first segments having enhanced service data and main service data, the second segments having enhanced service data and the plurality of known data sequences and the third segments having enhanced service data and main service data, wherein the enhanced service data in the first, second and third segments are encoded by non-systematic RS encoding, the main service data in the first and third segments are encoded by systematic RS encoding and at least two of the plurality of known data sequences have different patterns.

2. The method of claim 1, wherein the trellis encoder is initialized at a start of each known data sequence.

3. The method of claim 2, wherein the data group further includes initialization byte which is located as preceding each known data sequence and when the initialization byte is inputted to the trellis encoder, the trellis encoder is initialized.

4. The method of claim 1, wherein the second randomizing is not performed for the enhanced service data in the multiplexed enhanced and main service data packets.

5. An apparatus for transmitting a digital broadcast signal, the apparatus comprising:

a first randomizer configured to first randomize enhanced service data;

a Reed-Solomon (RS) encoder configured to RS encode the first randomized enhanced service data for each column of at least one RS frame payload and adding Cyclic Redundancy Check (CRC) checksum byte at right end of each row of the at least one RS frame payload to build at least one RS frame;

a group formatter configured to form data groups including the enhanced service data in the built RS frame and a plurality of known data sequences;

a packet formatter configured to format enhanced service data packets including the enhanced service data and the plurality of known data sequences in the data groups;

a multiplexer configured to multiplex the enhanced service data packets with main service data packets including main service data;

a second randomizer configured to perform second randomizing for the main service data in the multiplexed enhanced and main service data packets; and

a trellis encoder configured to trellis-encode the enhanced service data and randomized main service data,

wherein a data group having the trellis-encoded enhanced service data and main service data includes first segments, second segments and third segments, the second segments being positioned between the first and third segments, the first segments having enhanced service data and main service data, the second segments having enhanced service data and the plurality of known data sequences and the third segments having enhanced service data and main service data, wherein the enhanced service data in the first, second and third segments are encoded by non-systematic RS encoding, the main service data in the first and third segments are encoded by systematic RS encoding and at least two of the plurality of known data sequences have different patterns.

6. The apparatus of claim 5, wherein the trellis encoder is initialized at a start of each known data sequence.

7. The apparatus of claim 6, wherein the data group further includes initialization byte which is located as preceding each known data sequence and when the initialization byte is inputted to the trellis encoder, the trellis encoder is initialized.

8. The apparatus of claim 5, wherein the second randomizing is not performed for the enhanced service data in the multiplexed enhanced and main service data packets.