Incremental redundancy with space-time codes

• US 20040057530A1
• Filed: 09/20/2002
• Published: 03/25/2004
• Est. Priority Date: 09/20/2002
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Tong, Wen, Ma, Jianglei, Tarokh, Vahid, Zhu, Peiying, Jia, Ming
• Granted Patent: US 7,397,864 B2
• Time in Patent Office: Days
• US Class Current: 375/267
• CPC Class Codes: H04L 1/0625 Transmitter arrangements
• CPC Class Codes: H04L 1/1816 with retransmission of the same, encoded, message
• CPC Class Codes: H04L 1/1819 with retransmission of additional or different redundancy
• CPC Class Codes: H04L 1/1841 Resequencing
• CPC Class Codes: H04L 1/1845 Combining techniques, e.g. code combining
• CPC Class Codes: H04L 1/1893 Physical mapping arrangements physical resource mapping in general H04L5/00

Abstract

The present invention relates to space-time coding techniques capable of providing incremental redundancy in wireless communication environments incorporating spatial and temporal diversity. In general, a transmitter sends packets, via blocks of symbols, to a receiver with high bandwidth efficiency and only in the event that the receiver does not correctly receive a data packet does the transmitter send additional symbols to assist with the decoding of the incorrectly received packet. A hybrid ARQ feedback mechanism is used such that the receiver can inform the transmitter whether the packets were correctly or incorrectly received. From the feedback, the transmitter can determine whether to send new symbols or initiate incremental redundancy. By combining the received words corresponding to the redundant symbols and those of the original packet transmission, additional diversity, coding gain, signal energy, or a combination thereof are provided to the receiver and are used to correctly decode the transmitted data.

Claims

1. A wireless communication device comprising:

a) transmission circuitry adapted to transmit symbols to a remote device via a plurality of antennas to provide spatial diversity;

b) a space-time encoder associated with the transmission circuitry and adapted to facilitate space-time coding to provide original symbols for transmission and space-time coded retransmission symbols in response to a request from the remote device, the retransmission symbols corresponding to select ones of the original symbols requiring retransmission to the remote device.

2. The wireless communication device of claim 1 wherein the space-time encoder is further adapted to transmit a first set of original symbols during a first transmission period via the plurality of antennas and transmit a first set of retransmission symbols during a second transmission period, the retransmission symbols being the first set of original symbols reordered for transmission from different ones of the plurality of antennas than the first set of original symbols.

3. The wireless communication device of claim 1 wherein the space-time encoder is further adapted to transmit a first set of original symbols during a first transmission period via the plurality of antennas and transmit a first set of retransmission symbols during a second transmission period, the retransmission symbols being the first set of original symbols encoded and reordered for transmission from different ones of the plurality of antennas than the first set of original symbols.

4. The wireless communication device of claim 3 wherein the first set of retransmission symbols is encoded using space-time block codes.

5. The wireless communication device of claim 3 wherein the first set of retransmission symbols is encoded using space-time transmit diversity.

6. The wireless communication device of claim 3 wherein the space-time encoder is further adapted to transmit a second set of original symbols during a third transmission period via the plurality of antennas in response to a second request from the remote device.

7. The wireless communication device of claim 6 wherein the space-time encoder is further adapted to transmit a second set of retransmission symbols during a forth transmission period via the plurality of antennas in response to a third request from the remote device.

8. The wireless communication device of claim 6 wherein the first and second sets of original symbols correspond to one group of symbols.

9. The wireless communication device of claim 6 wherein the first and second sets of original symbols correspond to different groups of symbols.

10. The wireless communication device of claim 1 wherein the original symbols comprise subsets of symbols transmitted at consecutive times during a first transmission period and the retransmission symbols comprise subsets of retransmitted symbols transmitted at consecutive times during a second transmission period such that blocks of symbols are transmitted over the consecutive times during the first transmission period and blocks of retransmission symbols are transmitted over the consecutive times during the second transmission period.

11. The wireless communication device of claim 1 wherein the space-time encoder is further adapted to transmit a first set of original symbols during a first transmission period via the plurality of antennas and transmit a first set of retransmission symbols during a second transmission period, the retransmission symbols being the first set of original symbols encoded using Trellis encoding for transmission from the plurality of antennas.

12. The wireless communication device of claim 1 wherein the request from the remote device is provided according to an automatic retransmission request (ARQ) type protocol.

13. The wireless communication device of claim 12 wherein the request from the remote device is provided according to a hybrid ARQ (HARQ) type protocol.

14. A wireless communication device comprising:

a) receive circuitry adapted to recover original symbols and retransmission symbols from a remote device via a plurality of antennas to provide spatial diversity and send a request to the remote device to transmit the retransmission symbols; and

b) a space-time decoder associated with the receive circuitry and adapted to facilitate space-time decoding to recover the original symbols based on the original symbols and the retransmission symbols, the retransmission symbols corresponding to select ones of the original symbols requiring retransmission from the remote device.

15. The wireless communication device of claim 14 further comprising de-mapping logic adapted to determine soft bit decisions associated with the original and retransmitted symbols and a combiner adapted to process the soft bit decisions to provide hard bit decisions, and wherein:

c) the space-time decoder is further adapted to recover a first set of original symbols during a first transmission period via the plurality of antennas and recover a first set of retransmission symbols during a second transmission period; and

d) the combiner is further adapted to combine the soft bit decisions associated with the first set of original symbols with the soft bit decisions for the first set of retransmitted symbols to provide hard bit decisions for the first set of original symbols; and

e) wherein the first set of retransmission symbols are the first set of original symbols reordered for transmission from different ones of the plurality of antennas of the remote device than the first set of original symbols.

16. The wireless communication device of claim 14 wherein the space-time decoder is further adapted to:

c) recover a first set of original symbols during a first transmission period via the plurality of antennas;

d) decode the first set of original symbols using a first decoding technique to determine the original symbols, the first set of original symbols being improperly decoded;

e) recover a first set of retransmission symbols during a second transmission period; and

f) decode the first set of original symbols with the first set of retransmission symbols using a second decoding technique to determine the original symbols.

17. The wireless communication device of claim 16 wherein the first set of retransmission symbols are the first set of original symbols reordered for transmission from different ones of the plurality of antennas than the first set of original symbols.

18. The wireless communication device of claim 14 wherein the space-time decoder is further adapted to:

c) recover a first set of original symbols during a first transmission period via the plurality of antennas;

d) decode the first set of original symbols using a first decoding technique to determine the original symbols, the first set of original symbols being improperly decoded;

e) recover a first set of retransmission symbols during a second transmission period; and

f) decode the first set of original symbols with the first set of retransmission symbols using space-time block decoding to determine the original symbols.

19. The wireless communication device of claim 18 wherein the first decoding technique is BLAST.

20. The wireless communication device of claim 18 wherein the first set of original symbols and the first set of retransmission symbols are decoded using a generalized decoding technique even during varying channel conditions.

21. The wireless communication device of claim 14 wherein the space-time decoder is further adapted to:

c) recover a first set of original symbols during a first transmission period via the plurality of antennas;

d) decode the first set of original symbols using a first decoding technique to determine the original symbols, the first set of original symbols being improperly decoded;

e) recover a first set of retransmission symbols during a second transmission period;

f) decode the first set of original symbols with the first set of retransmission symbols using space-time block decoding to determine a first estimate for the original symbols, the first estimate for the original symbols being improperly decoded;

g) recover a second set of original symbols transmitted during a third transmission period; and

h) decode the second set of original symbols with the first set of retransmission symbols using space-time block decoding to determine a second estimate for the original symbols.

22. The wireless communication device of claim 21 further comprising de-mapping logic adapted to determine soft bit decisions associated with the original and retransmitted symbols and a combiner adapted to process the soft bit decisions to provide hard bit decisions, and wherein the soft bit decisions associated with the first and second estimates for the original symbols are combined by the combiner to provide hard bit estimates for the original symbols.

23. The wireless communication device of claim 14 wherein the space-time decoder is further adapted to:

c) recover a first set of original symbols during a first transmission period via the plurality of antennas;

d) recover a first set of retransmission symbols during a second transmission period,

e) decode the first set of original symbols with the first set of retransmission symbols using space-time block decoding to determine a first estimate for the original symbols, the first estimate for the original symbols being improperly decoded;

f) recover a second set of original symbols during a third transmission period;

g) recover a second set of retransmission symbols during a fourth transmission period; and

h) decode the second set of original symbols with the second set of retransmission symbols using space-time block decoding to determine a second estimate for the original symbols.

24. The wireless communication device of claim 23 further comprising de-mapping logic adapted to determine soft bit decisions associated with the original and retransmitted symbols and a combiner adapted to process the soft bit decisions to provide hard bit decisions, and wherein the soft bit decisions associated with the first and second estimates for the original symbols are combined by the combiner to provide hard bit estimates for the original symbols.

25. The wireless communication device of claim 14 wherein the space time decoder is further adapted to:

c) recover a first set of original symbols during a first transmission period via the plurality of antennas;

d) recover a first set of retransmission symbols during a second transmission period;

e) recover a second set of original symbols during the first transmission period;

f) recover a second set of retransmission symbols during the second transmission period;

g) decode the first and second sets of original symbols with the first and second sets of retransmission symbols using space-time block decoding to determine the original symbols.

26. The wireless communication device of claim 25 wherein the first and second sets of original symbols correspond to one group of symbols.

27. The wireless communication device of claim 25 wherein the first and second sets of original symbols correspond to different groups of symbols.

28. The wireless communication device of claim 14 wherein the original symbols comprise subsets of symbols transmitted at consecutive times during a first transmission period and the retransmission symbols comprise subsets of retransmitted symbols transmitted at consecutive times during a second transmission period such that blocks of symbols are transmitted over the consecutive times during the first transmission period and blocks of retransmission symbols are transmitted of the consecutive times during the second transmission period.

29. A method for facilitating wireless communications comprising:

a) transmitting original symbols to a remote device via a plurality of antennas to provide spatial diversity;

b) space-time encoding and transmitting retransmission symbols in response to a request from the remote device, the retransmission symbols corresponding to select ones of the original symbols requiring retransmission to the remote device.

30. The method of claim 29 further comprising transmitting a first set of original symbols during a first transmission period via the plurality of antennas and transmitting a first set of retransmission symbols during a second transmission period, the retransmission symbols being the first set of original symbols reordered for transmission from different ones of the plurality of antennas than the first set of original symbols.

31. The method of claim 29 further comprising transmitting a first set of original symbols during a first transmission period via the plurality of antennas and transmitting a first set of retransmission symbols during a second transmission period, the retransmission symbols being the first set of original symbols encoded and reordered for transmission from different ones of the plurality of antennas than the first set of original symbols.

32. The method of claim 31 wherein the first set of retransmission symbols is encoded using space-time block codes.

33. The method of claim 31 further comprising transmitting a second set of original symbols during a third transmission period via the plurality of antennas in response to a second request from the remote device.

34. The method of claim 33 further comprising transmitting a second set of retransmission symbols during a fourth transmission period via the plurality of antennas in response to a third request from the remote device.

35. The method of claim 34 wherein the first and second sets of original symbols correspond to one group of symbols.

36. The method of claim 34 wherein the first and second sets of original symbols correspond to different groups of symbols.

37. The method of claim 29 wherein the original symbols comprise subsets of symbols transmitted at consecutive times during a first transmission period and the retransmission symbols comprise subsets of retransmitted symbols transmitted at consecutive times during a second transmission period such that blocks of symbols are transmitted over the consecutive times during the first transmission period and blocks of retransmission symbols are transmitted over the consecutive times during the second transmission period.

38. The method of claim 29 further comprising transmitting a first set of original symbols during a first transmission period via the plurality of antennas and transmitting a first set of retransmission symbols during a second transmission period, the retransmission symbols being the first set of original symbols encoded using Trellis encoding for transmission from the plurality of antennas.

39. The method of claim 29 wherein the request from the remote device is provided according to an automatic retransmission request (ARQ) type protocol.

40. The method of claim 39 wherein the request from the remote device is provided according to a hybrid ARQ (HARQ) type protocol.

41. A method comprising:

a) recovering original symbols and retransmission symbols from a remote device via a plurality of antennas to provide spatial diversity;

b) sending a request to the remote device to transmit the retransmission symbols; and

c) space-time decoding to recover the original symbols based on the original symbols and the retransmission symbols, the retransmission symbols corresponding to select ones of the original symbols requiring retransmission from the remote device.

42. The method of claim 41 further comprising:

d) determining soft bit decisions associated with the original and retransmitted symbols;

e) processing the soft bit decisions;

f) recovering a first set of original symbols during a first transmission period via the plurality of antennas;

g) recovering a first set of retransmission symbols during a second transmission period, and

h) combining soft bit decisions associated with the first set of original symbols with soft bit decisions for the second set of retransmitted symbols to provide hard bit decisions for the first set of original symbols,

wherein the first set of retransmission symbols is the first set of original symbols reordered for transmission from different ones of the plurality of antennas of the remote device than the first set of original symbols.

43. The method of claim 41 further comprising:

d) recovering a first set of original symbols during a first transmission period via the plurality of antennas;

e) decoding the first set of original symbols using a first decoding technique to determine the original symbols, the first set of original symbols being improperly decoded;

f) recovering a first set of retransmission symbols during a second transmission period; and

g) decoding the first set of original symbols with the first set of retransmission symbols using a second decoding technique to determine the original symbols.

44. The method of claims 43 wherein the first set of retransmission symbols is the first set of original symbols reordered for transmission from different ones of the plurality of antennas than the first set of original symbols.

45. The method of claim 41 further comprising:

d) recovering a first set of original symbols during a first transmission period via the plurality of antennas;

e) decoding the first set of original symbols using a first decoding technique to determine the original symbols, the first set of original symbols being improperly decoded;

f) recovering a first set of retransmission symbols during a second transmission period; and

g) decoding the first set of original symbols with the first set of retransmission symbols using space-time block decoding to determine the original symbols.

46. The method of claim 45 wherein the first decoding technique is BLAST.

47. The method of claim 45 wherein the first set of original symbols and the first set of retransmission symbols are decoded using a generalized decoding technique even during varying channel conditions.

48. The method of claim 41 further comprising:

d) recovering a first set of original symbols during a first transmission period via the plurality of antennas;

e) decoding the first set of original symbols using a first decoding technique to determine the original symbols, the first set of original symbols being improperly decoded;

f) recovering a first set of retransmission symbols during a second transmission period,

g) decoding the first set of original symbols with the first set of retransmission symbols using space-time block decoding to determine a first estimate for the original symbols, the first estimate for the original symbols being improperly decoded;

h) recovering a second set of original symbols during a third transmission period; and

i) decoding the second set of original symbols with the first set of retransmission symbols using space-time block decoding to determine a second estimate for the original symbols.

49. The method of claim 48 further comprising determining soft bit decisions associated with the original and retransmitted symbols and combing soft bit decisions to provide hard bit decisions, and wherein soft bit decisions associated with the first and second estimates for the original symbols are combined by a combiner to provide hard bit estimates for the original symbols.

50. The method of claim 41 further comprising:

d) recovering a first set of original symbols during a first transmission period via the plurality of antennas;

e) recovering a first set of retransmission symbols during a second transmission period;

f) decoding the first set of original symbols with the first set of retransmission symbols using space-time block decoding to determine a first estimate for the original symbols, the first estimate for the original symbols being improperly decoded;

g) recovering a second set of original symbols during a third transmission period;

h) recovering a second set of retransmission symbols during a fourth transmission period; and

i) decoding the second set of original symbols with the second set of retransmission symbols using space-time block decoding to determine a second estimate for the original symbols.

51. The method of claim 50 further comprising determining soft bit decisions associated with the original and retransmitted symbols and combining the soft bit decisions to provide hard bit decisions, and wherein soft bit decisions associated with the first and second estimates for the original symbols are combined by the combiner to provide hard bit estimates for the original symbols.

52. The method of claim 41 further comprising:

d) recovering a first set of original symbols during a first transmission period via the plurality of antennas;

e) recovering a first set of retransmission symbols during a second transmission period;

f) recovering a second set of original symbols during the first transmission period;

g) recovering a second set of retransmission symbols during the second transmission period; and

h) decoding the first and second sets of original symbols with the first and second sets of retransmission symbols using space-time block decoding to determine the original symbols.

53. The method of claim 52 wherein the first and second sets of original symbols correspond to one group of symbols.

54. The method of claim 52 wherein the first and second sets of original symbols correspond to different groups of symbols.

55. The method of claim 41 wherein the original symbols comprise subsets of symbols transmitted at consecutive times during a first transmission period and the retransmission symbols comprise subsets of retransmitted symbols transmitted at consecutive times during a second transmission period such that blocks of symbols are transmitted over the consecutive times during the first transmission period and blocks of retransmission symbols are transmitted over the consecutive times during the second transmission period.