Distributed iterative decoding for co-operative diversity

• US 20080298474A1
• Filed: 05/30/2008
• Published: 12/04/2008
• Est. Priority Date: 05/31/2007
• Status: Active Grant

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Nokia Corporation
• Inventors: Charbit, Gilles, Cavallaro, Joseph R., Karkooti, Marjan, Lilleberg, Jorma O.
• Granted Patent: US 8,139,512 B2
• Time in Patent Office: Days
• US Class Current: 375/241
• CPC Class Codes: H04B 7/15592 Adapting at the relay station communication parameters for supporting cooperative relaying, i.e. transmission of the same data via direct - and relayed path cooperative diversity H04B7/024
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels
• CPC Class Codes: H04L 1/0045 Arrangements at the receiver end
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 2001/0097 Relays

Abstract

A source sends an encoded data block during a first time interval to a destination and to a relay. The source sends additional parity bits for the encoded data block during a second time interval. The relay partially decodes that encoded data block to a process-defined end point (typically only a partial decoding), such as a fixed number of decoding iterations. After partial decoding the relay forms a modified data block having corrected information bits and the parity bits of the block it received, and sends the modified data block to the destination, during the second time interval. The destination decodes to a results-defined end point the modified data block it received from the relay using the additional parity bits it received from the source. If that end-point cannot be reached, the destination may begin anew decoding the original encoded data block it received from the source.

Claims

1. A method comprising:

receiving from a source during a first time interval an encoded data block;

decoding the received encoded data block to a process-defined end point and from the decoding forming a modified version of the encoded data block; and

transmitting to a destination during a second time interval subsequent to the first time interval the modified version of the encoded data block.

2. The method of claim 1, wherein forming the modified version of the encoded data block comprises correcting information bits of the received encoded data block and re-using parity bits of the received encoded data block, without re-encoding prior to the transmitting.

3. The method of claim 1, wherein the process-defined end point comprises a fixed number of decoding iterations.

4. The method of claim 1 executed by a relay station, and wherein the first and second time intervals are consecutive.

5. The method of claim 1, wherein forming the modified version of the encoded data block comprises re-encoding with a code that is either a same code used to decode the received encoded data block or a new code selected for conditions of a channel over which the transmitting occurs.

6. A device comprising:

a receiver configured to receive from a source during a first time interval an encoded data block;

a decoder configured to decode the received encoded data block to a process-defined end point;

a processor configured to form from the decoded received encoded data block a modified version of the encoded data block; and

a transmitter configured to transmit to a destination during a second time interval subsequent to the first time interval the modified version of the encoded data block.

7. The device of claim 6, wherein the processor is configured to form the modified version of the encoded data block by correcting information bits of the received encoded data block and re-using parity bits of the received encoded data block, without re-encoding prior to the modified version of the encoded data block being transmitted by the transmitter.

8. The device of claim 6, wherein the process-defined end point comprises a fixed number of decoding iterations.

9. The device of claim 6, wherein the device comprises a relay station and wherein the first and second time intervals are consecutive.

10. The device of claim 6, further comprising an encoder that is configured, with the processor, to form the modified version of the encoded data block by re-encoding the data block decoded by the decoder with a code that is either a same code used by the decoder to decode the received encoded data block or a new code that is selected by the processor for conditions of a channel over which the transmitter transmits the modified version of the encoded data block.

11. A computer readable memory embodying a computer program that is executable by a processor to perform actions directed to distributed decoding, the actions comprising:

decoding to a process-defined end point an encoded data block that is received from a source during a first time interval;

from the decoding, forming a modified version of the encoded data block; and

transmitting to a destination during a second time interval subsequent to the first time interval the modified version of the encoded data block.

12. The computer readable memory of claim 11, wherein forming the modified version of the encoded data block comprises correcting information bits of the received encoded data block and re-using parity bits of the received encoded data block, without re-encoding prior to the transmitting.

13. The computer readable memory of claim 11, wherein the process-defined end point comprises a fixed number of decoding iterations.

14. The computer readable memory of claim 11, wherein forming the modified version of the encoded data block comprises re-encoding with a code that is either a same code used to decode the received encoded data block or a new code selected for conditions of a channel over which the transmitting occurs.

15. A method comprising:

receiving from a source during a first time interval an encoded data block;

receiving from the source during a second time interval additional error correction data;

receiving from a relay a modified version of the encoded data block; and

decoding the modified version of the encoded data block received from the relay using the additional error correction data received from the source.

16. The method of claim 15, wherein the modified version of the encoded data block comprises the encoded data block that is partially decoded to a process-defined end point, and wherein decoding the modified version of the encoded data block using the additional error correction data comprises decoding towards a results-defined end point.

17. The method of claim 16, wherein for the case where decoding the modified version of the encoded data block using the additional error correction data fails to reach the results-defined end point, the method further comprising decoding the encoded data block received from the source to the results-defined end point.

18. The method of claim 15, executed by one of a base station and an access node, and wherein the modified version of the encoded data block is received in the second time interval.

19. The method of claim 15, wherein the additional error correction data comprises parity bits for the encoded data block received from the source.

20. The method of claim 15, wherein decoding the modified version of the encoded data block is with a code that differs from another code with which the encoded data block received from the source is encoded.

21. A device comprising:

at least one receiver configured to receive from a source during a first time interval an encoded data block, and to receive from the source during a second time interval additional error correction data, and to receive from a relay a modified version of the encoded data block; and

a decoder configured to decode the modified version of the encoded data block received from the relay using the additional error correction data received from the source.

22. The device of claim 21, further comprising a processor configured to impose on the decoder a results-defined end point,

wherein the modified version of the encoded data block comprises the encoded data block that is partially decoded to a process-defined end point,

and wherein the decoder is configured to decode the modified version of the encoded data block using the additional error correction data towards the results-defined end point.

23. The device of claim 22, wherein for the case where the decoder fails to reach the results-defined end point when decoding the modified version of the encoded data block using the additional error correction data, the processor is further configured to cause the decoder to decode to the results-defined end point the encoded data block received from the source.

24. The device of claim 21, wherein the device comprises one of a base station and an access node, and wherein receiver is configured to receive the modified version of the encoded data block in the second time interval.

25. The device of claim 21, wherein the additional error correction data comprises parity bits for the encoded data block received from the source.

26. The device of claim 21, wherein the decoder is configured to decode the modified version of the encoded data block using a code that differs from another code with which is encoded the encoded data block that the receiver received from the source.

27. A computer readable memory embodying a computer program that is executable by a processor to perform actions directed to distributed decoding, the actions comprising:

responsive to receiving from a source during a first time interval an encoded data block, and receiving from the source during a second time interval additional error correction data, and receiving from a relay a modified version of the encoded data block;

decoding the modified version of the encoded data block received from the relay using the additional error correction data received from the source.

28. The computer readable memory of claim 27, wherein the modified version of the encoded data block comprises the encoded data block that is partially decoded to a process-defined end point,

and wherein decoding the modified version of the encoded data block using the additional error correction data comprises decoding towards a results-defined end point,

and wherein the additional error correction data comprises parity bits for the encoded data block received from the source

29. The computer readable memory of claim 27, wherein for the case where decoding the modified version of the encoded data block using the additional error correction data fails to reach the results-defined end point, the actions further comprise decoding the encoded data block received from the source to the results-defined end point.

30. The computer readable memory of claim 27, wherein decoding the modified version of the encoded data block is with a code that differs from another code with which the encoded data block received from the source is encoded.

31. A device comprising:

a processor configured to encode information bits into an encoded block of data that comprises the information bits and a first set of parity bits for the information bits, and further configured to compute a second set of parity bits for the information bits; and

a transmitter configured to transmit the encoded block of data to a destination and to a relay, and further configured to transmit the second set of parity bits, without the information bits, at least to the destination.