Tailored error protection

• US 5,463,641 A
• Filed: 07/16/1993
• Issued: 10/31/1995
• Est. Priority Date: 07/16/1993
• Status: Expired due to Term

• Current Assignee: AT&T IPM Corp. (AT&T, Inc.)
• Original Assignee: AT&T IPM Corp. (AT&T, Inc.)
• Inventors: Quackenbush, Schuyler R., Seshadri, Nambirajan, Johnston, James D., Sundberg, Carl-Erik W., Dorward, Sean M., Jayant, Nuggehally S.
• Primary Examiner(s): Baker, Stephen M.
• Application Number:
  US08/092,623
• Time in Patent Office: 837 Days
• Field of Search: 371/30, 371/37.1, 371/37.4, 371/37.5, 371/41, 371/43
• US Class Current: 714/755
• CPC Class Codes: H03M 13/1515 Reed-Solomon codes
• CPC Class Codes: H03M 13/27 using interleaving techniques
• CPC Class Codes: H03M 13/29 combining two or more codes or code structures, e.g. product codes, generalised product codes, concatenated codes, inner and outer codes
• CPC Class Codes: H03M 13/2903 Methods and arrangements specifically for encoding, e.g. parallel encoding of a plurality of constituent codes
• CPC Class Codes: H03M 13/35 Unequal or adaptive error protection, e.g. by providing a different level of protection according to significance of source information or by adapting the coding according to the change of transmission channel characteristics
• CPC Class Codes: H03M 13/6513 Support of multiple code types, e.g. unified decoder for LDPC and turbo codes
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 1/0065 Serial concatenated codes
• CPC Class Codes: H04L 1/007 Unequal error protection for format H04L1/0078; for codes per se H03M13/35
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27

Abstract

A method of tailored error protection coding is disclosed. An illustrative coding method according to the present invention concerns encoding a first signal and a second signal to provide error protection for the signals, wherein the first signal requires greater error protection than the second signal. According to the method, the first signal is encoded with a first error protection code. The encoded first signal is then combined with the second signal. The combination of the encoded first signal and the second signal is further encoded with a second error protection code to generate a combined error protected signal, wherein the first signal is coded with both the first and second error protection codes. A second embodiment concerns the use of separate coders which apply different error protection codes to two signals. The two encoded signals are then combined into a single signal.

Claims

1. A method for encoding a first signal and a second signal to provide error protection for the signals, the first signal requiring greater error protection than the second signal, the first and second signals for use in communication with a receiver, the receiver for producing decoded first and second signals corresponding to the first and second signals, respectively, the method comprising the steps of:

a. encoding the first signal with a first error protection code;

b. combining the encoded first signal with the second signal; and

c. encoding a combination of the encoded first signal and the second signal with a second error protection code to generate a combined error protected signal for use in transmission to the receiver, wherein the first signal is coded with both the first and second error protection codes;

wherein said first signal is such that the decoded first signal, when irreparably corrupted due to transmission of said combined error protected signal, will not affect correct processing of the decoded second signal by the receiver.

2. The method of claim 1 where said first signal comprises alphanumeric data.

3. The method of claim 1 wherein the step of encoding the first signal comprises applying a Reed-Solomon error correction code to the first signal.

4. The method of claim 1 wherein the step of encoding the first signal comprises applying a binary block code to the first signal.

5. The method of claim 1 further comprising the step of interleaving the encoded first signal.

6. The method of claim 1 wherein the step of encoding the combination comprises applying a Reed-Solomon error correction code.

7. The method of claim 1 further comprising the steps of:

compressing said audio signal in accordance with a model of human audio perception;

applying an interleaver process to the encoded first signal;

applying an interleaver process to the combined error protected signal; and

transmitting a signal representing the combined error protected signal.

8. The method of claim 1 further comprising the step of applying an interleaver process to the combined error protected signal.

9. The method of claim 8 further comprising the step of transmitting a signal representing the combined error protected signal.

10. The method of claim 1 wherein said second signal comprises an audio signal.

11. The method of claim 10 further comprising the step of compressing said audio signal.

12. The method of claim 11 wherein the step of compressing is performed in accordance with a model of human audio perception.

13. A method for decoding a signal received by a receiver, the signal received representing a coded first signal and a coded second signal, wherein the coded first signal is based on a first signal coded with use of a first and a second error protection code and wherein the coded second signal is based on a second signal coded with use of the second error protection code, the first signal requiring greater error protection than the second signal, the method comprising the steps of:

a. decoding the received signal with a first error protection decoder which corresponds to the first error protection code to generate a signal comprising a decoded second signal and a partially decoded first signal;

b. separating the partially decoded first signal from the decoded second signal; and

c. decoding the partially decoded first signal with a second error protection decoder which corresponds to the second error protection code to generate a decoded first signal, wherein the coded first signal is decoded with both the first and second error protection decoders;

wherein said first signal is such that the decoded first signal, when irreparably corrupted due to transmission, will not affect correct processing of the decoded second signal by the receiver.

14. The method of claim 13 further comprising the step of applying a deinterleaver process to the received signal.

15. The method of claim 13 further comprising the step of applying a deinterleaver process to the partially decoded first signal.

16. The method of claim 13 further comprising the step of applying an audio decompression system to the decoded second signal to generate a decompressed audio signal.

17. The method of claim 13 wherein the decoded first signal represents alphanumeric data.

18. The method of claim 13 further comprising the steps of:

applying a deinterleaver process to the received signal;

applying a deinterleaver process to the partially decoded first signal; and

applying an audio decompression system to the decoded second signal to generate a decompressed audio signal.