Method and apparatus for adaptive control of forward error correction codes

• US 6,477,669 B1
• Filed: 01/18/2000
• Issued: 11/05/2002
• Est. Priority Date: 07/15/1997
• Status: Expired due to Term

• Current Assignee: ViaSat Incorporated
• Original Assignee: COMSAT Corporation (Reorganized ISA SA)
• Inventors: Agarwal, Anil K., Chitre, Dattakumar M.
• Primary Examiner(s): Baker, Stephen M.
• Application Number:
  US09/462,893
• Time in Patent Office: 1,022 Days
• Field of Search: 714/708, 714/774
• US Class Current: 714/708
• CPC Class Codes: H03M 13/6312 Error control coding in combination with data compression
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system
• CPC Class Codes: H04B 7/18543 for adaptation of transmission parameters, e.g. power control for detecting or preventing errors in the information received H04L1/00
• CPC Class Codes: H04J 3/0608 Detectors therefor, e.g. correlators, state machines
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/0083 Formatting with frames or packets; Protocol or part of protocol for error control
• CPC Class Codes: H04L 12/5601 Transfer mode dependent, e.g. ATM
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/2491 Mapping quality of service [QoS] requirements between different networks
• CPC Class Codes: H04L 47/43 Assembling or disassembling of packets, e.g. segmentation and reassembly [SAR]
• CPC Class Codes: H04L 5/023 Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601
• CPC Class Codes: H04L 5/06 the signals being represented by different frequencies combined with time-division multiplexing H04L5/26

Abstract

A method for adaptive control of a forward error correction code for transmission between a terrestrial cell/packet switch at a first terminal and a satellite/wireless network connecting to a second terminal, including the steps of: calculating a byte error rate associated with communication signals received by the first terminal, determining a forward error correction code length based on the byte error rate, and transmitting the forward error correction code length to the second terminal.

Claims

1. In an interconnect apparatus disposed between a terrestrial cell and/or packet switch at a first terminal and one or both of a satellite and wireless network connecting to a second terminal, a method for the adaptive control of a forward error correction code for transmission over a communication channel which connects said first terminal to said second terminal, said method comprising the steps of:

calculating a byte error rate associated with communication signals received by said first terminal via said communication channel from said second terminal;

determining a forward error correction code length of said forward error correction code based on said byte error rate, said forward error correction code length being varied in accordance with said byte error rate;

transmitting said forward error correction code length to said second terminal over said communication channel; and

changing the forward error correction code at said first and second terminals in a synchronized manner without data loss.

2. The method of claim 1, wherein said step of calculating said byte error rate is performed at a predetermined interval based on said byte error rate.

3. The method of claim 2, wherein said byte error rate is calculated according to one of a plurality of formulas based on a prior byte error rate.

4. The method according to claim 1, wherein said steps of calculating and determining are performed only if said first terminal and said second terminal are synchronized.

5. The method according to claim 4, wherein if said first terminal and said second terminal are unsynchronized, said forward error correction code length transmitted to said remote interface will correspond to a predetermined maximum value thereof.

6. The method according to claim 1, wherein said forward error correction code is at least one of a Viterbi Code and a Reed-Solomon Code.

7. The method according to claim 1, wherein said forward error correction code length is transmitted in a predetermined communication signal over said communication channel.

8. The method according to claim 7, wherein said forward error correction code length is transmitted in a frame relay-based frame included in said predetermined communication signal.

9. The method according to claim 7, wherein said forward error correction code length is transmitted in an ISDN-based frame included in said predetermined communication signal.

10. The method according to claim 7, wherein said forward error correction code length is transmitted in an Internet-based frame included in said predetermined communication signal.

11. The method according to claim 7, wherein said forward error correction code length is transmitted in an ATM-based frame included in said predetermined communication signal.

12. The method according to claim 7, wherein said forward error correction code is a Reed-Solomon Code.

13. The method according to claim 7, wherein said forward error correction code is a Viterbi Code.

14. In an interconnection apparatus at a first terminal disposed between a cell and/or packet switch and one or both of a satellite and wireless communication network, an apparatus for the adaptive control of a forward error correction code for transmission over a communication channel which connects said first terminal to a second terminal, said apparatus comprising:

means for calculating a byte error rate associated with communication signals received by the first terminal via said communication channel from said second terminal;

means for determining a forward error correction code length of said forward error correction code based on said byte error rate, said forward error correction code length being varied in accordance with said byte error rate; and

means for transmitting said forward error correction code length to the second terminal over said communication channel;

whereby

the forward error correction code at said first and second terminals may be changed in a synchronized manner without loss of data.

15. The apparatus according to claim 14, wherein said forward error correction code is at least one of a Viterbi Code and a Reed-Solomon Code.

16. The apparatus according to claim 14, wherein said forward error correction code length is transmitted in a predetermined communication signal over said communication channel, said predetermined communication signal being recognized by said first terminal and said second terminal.

17. The apparatus according to claim 16, wherein said forward error correction code length is transmitted in an ATM-based frame included in said predetermined communication signal.

18. The apparatus according to claim 16, wherein said forward error correction code length is transmitted in a frame relay-based frame included in said predetermined communication signal.

19. The apparatus according to claim 16, wherein said forward error correction code length is transmitted in an ISDN-based frame included in said predetermined communication signal.

20. The apparatus according to claim 16, wherein said forward error correction code length is transmitted in an Internet-based frame included in said predetermined communication signal.