Systems for reducing adverse effects of deep fades in DTV signals designed for mobile reception

• US 20130002962A1
• Filed: 09/10/2012
• Published: 01/03/2013
• Est. Priority Date: 07/11/2007
• Status: Active Grant

• Current Assignee: Broadqast Solutions, LLC (Brian Yates)
• Original Assignee: Allen Leroy Limberg
• Inventors: Limberg, Allen LeRoy
• Granted Patent: US 8,649,429 B2
• Time in Patent Office: Days
• US Class Current: 348/724
• CPC Class Codes: H03M 13/2957 Turbo codes and decoding
• CPC Class Codes: H04L 65/611 for multicast or broadcast systems for broadcast or conference H04L12/18; arrangements for broadcast or distribution combined with broadcast H04H20/00; arrangements for broadcast applications with a direct linkage to broadcast information or to broadcast space-time H04H60/00; selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS], H04W4/06
• CPC Class Codes: H04L 65/70 Media network packetisation
• CPC Class Codes: H04N 21/2383 Channel coding or modulation of digital bit-stream, e.g. QPSK modulation arrangements for detecting or preventing errors in the information received by adapting the channel coding H04L1/0009; analogue front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002

Abstract

Digital television broadcasting signals employ parallel concatenated convolutional coding, commonly called “turbo coding”, to improve reception by receivers in motor vehicles. Turbo coded Reed-Solomon codewords are transversally disposed in the payload fields of encapsulating MPEG-2-compliant packets to improve the capability of the Reed-Solomon coding to overcome deep fades. Turbo codewords are transmitted more than once in so-called “staggercasting”. Reception of DTV signals is improved by combining soft decisions concerning repeated transmissions of turbo codewords before turbo decoding. Only the data components of turbo codewords are transmitted twice in “punctured” staggercasting of turbo codewords, with parity components being transmitted only once, so code rate is reduced by a smaller factor than two.

Claims

1. In transmitter apparatus for a digital television broadcast signal manifested as an electromagnetic wave subjected to vestigial sideband amplitude modulation in accordance with an eight-level modulating signal, said eight-level modulating signal formed by two-thirds trellis coding of convolutionally byte-interleaved 207-byte Reed-Solomon codewords generated from 187-byte packets beginning with respective 3-byte headers and concluding with respective 184-byte contents, the improvement wherein:

the contents of selected ones of said 187-byte packets encapsulate data bits of parallel concatenated convolutional coding of ancillary digital data, said data bits of said parallel concatenated convolutional coding being temporally interleaved with first and second sets of parity bits of said parallel concatenated convolutional coding that are also encapsulated in said selected ones of said 187-byte packets.

2. The improvement set forth in claim 1, wherein said parallel concatenated convolutional coding is interleaved before encapsulation within said selected ones of said 187-byte packets.

3. The improvement set forth in claim 1, wherein there is block interleaving of said parallel concatenated convolutional coding that is encapsulated within said selected ones of said 187-byte packets.

4. The improvement set forth in claim 1, wherein said ancillary digital data are initially Reed-Solomon coded prior to said parallel concatenated convolutional coding thereof.

5. The improvement set forth in claim 1, wherein said ancillary digital data are initially Reed-Solomon coded prior to said parallel concatenated convolutional coding and said block interleaving thereof.

6. Transmitter apparatus for transmitting a digital television broadcast signal manifested as an electromagnetic wave subjected to vestigial sideband amplitude modulation in accordance with an eight-level modulating signal, said eight-level modulating signal formed by two-thirds trellis coding of convolutionally byte-interleaved 207-byte Reed-Solomon codewords generated from 187-byte packets beginning with respective 3-byte headers and concluding with respective 184-byte contents, selected ones of said 187-byte packets encapsulating segments of parallel concatenated convolutional coding, said transmitter apparatus comprising:

a first Reed-Solomon encoder connected for coding ancillary digital data to generate successive bytes of Reed-Solomon-coded ancillary digital data;

a block interleaver connected for generating a block interleaver response to said successive bytes of Reed-Solomon-coded ancillary digital data;

apparatus for generating said parallel concatenated convolutional coding responsive to said block interleaver response;

a second Reed-Solomon encoder connected for coding said 187-byte packets beginning with respective 3-byte headers and concluding with respective 184-byte contents, including said selected ones of said 187-byte packets encapsulating said segments of said parallel concatenated convolutional coding, to generate (207,

     187) Reed Solomon codewords responsive to respective ones of said 187-byte packets;

a convolutional byte-interleaver connected for generating a convolutionally interleaved response to successive bytes of successive said (207,

     187) Reed Solomon codewords generated by said second Reed-Solomon encoder;

a 12-phase trellis code encoder connected for generating two-thirds-rate trellis coding in response to said convolutionally interleaved response from said convolutional byte-interleaver; and

an 8-level symbol mapper connected for generating said eight-level modulating signal responsive to said two-thirds-rate trellis coding from said 12-phase trellis code encoder.

7. Receiver apparatus for receiving a digital television broadcast signal manifested as an electromagnetic wave subjected to vestigial sideband amplitude modulation in accordance with an eight-level modulating signal, said eight-level modulating signal formed at least in part by 12-phase two-thirds trellis coding of convolutionally byte-interleaved 207-byte Reed-Solomon codewords generated from 187-byte packets beginning with respective 3-byte headers and concluding with respective 184-byte contents, wherein the contents of selected ones of said 187-byte packets encapsulate data bits of parallel concatenated convolutional coding of ancillary digital data, said data bits of said parallel concatenated convolutional coding being temporally interleaved with first and second sets of parity bits of said parallel concatenated convolutional coding that are also encapsulated in said selected ones of said 187-byte packets, said receiver comprising:

apparatus for converting the received improved digital television broadcast signal to a digitized baseband signal;

a 12-phase trellis code decoder connected for reproducing said convolutionally byte-interleaved 207-byte Reed-Solomon codewords responsive to said digitized baseband signal;

memory operable for de-interleaving said convolutionally byte-interleaved 207-byte Reed-Solomon codewords reproduced by said 12-phase trellis code decoder, thus to supply de-interleaved 207-byte Reed-Solomon codewords;

a decoder for decoding said de-interleaved 207-byte Reed-Solomon codewords to recover 187-byte packets; and

apparatus for decoding the contents of said selected ones of said 187-byte packets that encapsulate data bits of said parallel concatenated convolutional coding of ancillary digital data temporally interleaved with first and second sets of parity bits of said parallel concatenated convolutional coding, thus to recover said ancillary digital data.

8. Receiver apparatus as set forth in claim 7, wherein said ancillary digital data encapsulated within said selected ones of said 187-byte packets have been Reed-Solomon coded previously to said parallel concatenated convolutional coding of said ancillary digital data, and wherein said apparatus for decoding the contents of said selected ones of said 187-byte packets that encapsulate data bits of said parallel concatenated convolutional coding of ancillary digital data temporally interleaved with first and second sets of parity bits of said parallel concatenated convolutional coding comprises:

a decoder of said parallel concatenated convolutional coding connected for recovering previously Reed-Solomon coded ancillary digital data; and

a decoder for decoding said previously Reed-Solomon coded ancillary digital data to recover said ancillary digital data.

9. Receiver apparatus as set forth in claim 7, wherein said ancillary digital data encapsulated within said selected ones of said 187-byte packets have been Reed-Solomon coded previously to said parallel concatenated convolutional coding of said ancillary digital data and block interleaved, and wherein said apparatus for decoding the contents of said selected ones of said 187-byte packets that encapsulate data bits of said parallel concatenated convolutional coding of ancillary digital data temporally interleaved with first and second sets of parity bits of said parallel concatenated convolutional coding comprises

a decoder of said parallel concatenated convolutional coding connected for recovering block-interleaved bytes of said previously Reed-Solomon coded ancillary digital data;

a block de-interleaver for de-interleaving said block-interleaved bytes of said previously Reed-Solomon coded ancillary data, to generate Reed-Solomon-coded ancillary digital data; and

a decoder for decoding said Reed-Solomon coded ancillary digital data to recover said ancillary digital data.