System and Method for Adapting Codebooks

• US 20110243207A1
• Filed: 01/21/2011
• Published: 10/06/2011
• Est. Priority Date: 04/05/2010
• Status: Abandoned Application

• Current Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Inventors: Xia, Pengfei, Tang, Yang
• Application Number:
  US13/011,679
• Publication Number:
  US 20110243207A1
• Time in Patent Office: Days
• US Class Current: 375/224
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04L 2025/03808 Transmission of equaliser coefficients
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end

Abstract

A system and method for adapting codebooks are provided. A method for communications device operations includes receiving a pilot signal, computing a channel estimate for a channel between a controller and a communications device, the computing being based on the pilot signal, adapting a codebook based on the channel estimate and positions of codewords in the codebook, computing a representation of the channel using the adapted codebook, transmitting the representation of the channel as feedback information, and receiving a transmission beamformed based on the feedback information.

Claims

1. A method for communications device operations, the method comprising:

receiving a pilot signal;

computing a channel estimate for a channel between a controller and a communications device, the computing being based on the pilot signal;

adapting a codebook based on the channel estimate and positions of codewords in the codebook;

computing a representation of the channel using the adapted codebook;

transmitting the representation of the channel as feedback information; and

receiving a transmission beamformed based on the feedback information.

2. The method of claim 1, wherein adapting a codebook comprises applying a transform to a subset of codewords in the codebook.

3. The method of claim 2, wherein applying a transform to a subset of codewords comprises:

applying a desired transform to codewords in the subset of codewords; and

applying an identity transform to remaining codewords in the codebook.

4. The method of claim 3, wherein the identity transform comprises channel information raised to a zero power.

5. The method of claim 2, wherein the transform is based on long term channel statistics.

6. The method of claim 5, wherein the long term channel statistics are based on the channel estimate, information provided by the controller, or a combination thereof.

7. The method of claim 1, wherein adapting a codebook comprises extending the codebook to a new codebook, wherein the new codebook is larger than the codebook.

8. The method of claim 7, wherein the codebook has N1 codewords and the new codebook has P*N1 codewords, where N1 and P are integer values, and wherein extending the codebook comprises:

transforming the codebook with P transforms; and

forming the new codebook with results of each of the P transformations.

9. The method of claim 8, wherein P transforms comprise unitary matrices, diagonal matrices, permutations of diagonal matrices, unitary matrices, or combinations thereof.

10. The method of claim 7, wherein the codebook has N1 codewords and the new codebook has K codewords, where K is not a multiple of N1, K>

P*N1 but K<

(P+1)*N1, where K, N1, and P are integer values, and wherein extending the codebook comprises;

transforming the codebook with P transforms;

transforming a subset of the codebook with a transform; and

forming the new codebook with results of each of the P transformations and the transformation.

11. The method of claim 10, wherein P transforms and the transform comprise unitary matrices, diagonal matrices, permutations of diagonal matrices, unitary matrices, or combinations thereof.

12. The method of claim 10, wherein the subset of the codebook comprises selected columns of the codebook.

13. The method of claim 7, wherein the codebook is partitioned into M parts, where M is an integer value, and wherein extending the codebook comprises:

transforming each of the M parts of the codebook with a transform; and

forming the new codebook with results of the transformation of each of the M parts.

14. The method of claim 7, wherein the codebook is partitioned into M parts, where M is an integer value, and wherein extending the codebook comprises:

applying at least one transform to codewords in at least one part of the codebook; and

applying a zero transform to remaining parts of the codebook.

15. The method of claim 14, wherein the zero transform comprises a zero matrix.

16. A method for controller operations, the method comprising:

receiving feedback information from a communications device, wherein the feedback information comprises quantized channel information;

adapting a codebook based on the feedback information and positions of codewords in the codebook;

reconstructing channel information using the feedback information and the adapted codebook;

adjusting a transmitter based on the reconstructed channel information; and

transmitting information to the communications device using the adjusted transmitter.

17. The method of claim 16, wherein adapting a codebook comprises applying a transform to a subset of codewords in the codebook.

18. The method of claim 17, wherein applying a transform to a subset of codewords comprises:

applying a desired transform to codewords in the subset of codewords; and

applying an identity transform to remaining codewords in the codebook.

19. The method of claim 16, wherein adapting a codebook comprises extending the codebook to a new codebook, wherein the new codebook is larger than the codebook.

20. The method of claim 19, wherein the codebook has N1 codewords and the new codebook has P*N1 codewords, where N1 and P are integer values, and wherein extending the codebook comprises:

transforming the codebook with P transforms; and

forming the new codebook with results of each of the P transformations.

21. The method of claim 19, wherein the codebook has N1 codewords and the new codebook has K codewords, where K is not a multiple of N1, K>

P*N1 but K<

(P+1)*N1, where K, N1, and P are integer values, and wherein extending the codebook comprises;

transforming the codebook with P transforms;

transforming a subset of the codebook with a transform; and

forming the new codebook with results of each of the P transformations and the transformation.

22. The method of claim 19, wherein the codebook is partitioned into M parts, where M is an integer value, and wherein extending the codebook comprises:

transforming each of the M parts of the codebook with a transform; and

forming the new codebook with results of the transformation of each of the M parts.

23. The method of claim 19, wherein the codebook is partitioned into M parts, where M is an integer value, and wherein extending the codebook comprises:

applying a transform to codewords in at least one part of the codebook; and

applying a zero transform to remaining parts of the codebook.

24. A communications device comprising:

a receiver configured to receive a pilot signal;

a channel estimate unit coupled to the receiver, the channel estimate unit configured to compute a channel estimate based on the pilot signal for a channel between a controller and the communications device;

an adaptation unit coupled to the channel estimate unit, the adaptation unit configured to adapt a codebook based on the channel estimate and positions of codewords in the codebook;

a channel representation unit coupled to the adaptation unit, the channel representation unit configured to compute a representation of the channel; and

a transmitter coupled to the channel estimate unit and to the channel representation unit, the transmitter configured to transmit the representation of the channel.

25. The communications device of claim 24, wherein the adaptation unit is configured to adapt the codebook by applying a transform to a subset of codewords in the codebook.

26. The communications device of claim 25, wherein the adaptation adapts the codebook by applying a desired transform to codewords in the subset of codewords and applying an identity transform to remaining codewords in the codebook.

27. The communications device of claim 24, wherein the adaptation unit is configured to adapt the codebook by extending the codebook to a new codebook, wherein the new codebook is larger than the codebook.

28. The communications device of claim 27, wherein the codebook has N1 codewords and the new codebook has P*N1 codewords, where N1 and P are integer values, and wherein the adaptation unit extends the codebook by transforming the codebook with P transforms, and forming the new codebook with results of each of the P transformations.

29. The communications device of claim 27, wherein the codebook has N1 codewords and the new codebook has K codewords, where K is not a multiple of N1, K>

P*N1 but K<

(P+1)*N1, where K, N1, and P are integer values, and wherein the adaptation unit extends the codebook by transforming the codebook with P transforms, transforming a subset of the codebook with a transform, and forming the new codebook with results of each of the P transformations and the transformation.

30. The communications device of claim 27, wherein the codebook is partitioned into M parts, where M is an integer value, and wherein the adaptation unit extends the codebook by transforming each of the M parts of the codebook with a transform, and forming the new codebook with results of the transformation of each of the M parts.

31. The communications device of claim 27, wherein the codebook is partitioned into M parts, where M is an integer value, and wherein the adaptation unit extends the codebook by applying at least one transform to codewords in at least one part of the codebook, and applying a zero transform to remaining parts of the codebook.

32. A controller comprising:

a receiver configured to receive feedback information;

an adaptation unit coupled to the receiver, the adaptation unit configured to adapt a codebook based on the feedback information and positions of codewords in the codebook;

a reconstruction unit coupled to the receiver and to the adaptation unit, the reconstruction unit configured to reconstruct channel information using the feedback information and the adapted codebook;

an adjusting unit coupled to the reconstruction unit, the adjusting unit configured to adjust a transmitter based on the reconstructed channel information; and

a transmitter coupled to the adjusting unit, the transmitter configured to transmit information to a communications device.

33. The controller of claim 32, wherein the adaptation unit is configured to adapt the codebook by applying a transform to a subset of codewords in the codebook.

34. The controller of claim 33, wherein the adaptation adapts the codebook by applying a desired transform to codewords in the subset of codewords and applying an identity transform to remaining codewords in the codebook.

35. The controller of claim 32, wherein the adaptation unit is configured to adapt the codebook by extending the codebook to a new codebook, wherein the new codebook is larger than the codebook.

36. The controller of claim 35, wherein the codebook has N1 codewords and the new codebook has P*N1 codewords, where N1 and P are integer values, and wherein the adaptation unit extends the codebook by transforming the codebook with P transforms, and forming the new codebook with results of each of the P transformations.

37. The controller of claim 35, wherein the codebook has N1 codewords and the new codebook has K codewords, where K is not a multiple of N1, K>

P*N1 but K<

(P+1)*N1, where K, N1, and P are integer values, and wherein the adaptation unit extends the codebook by transforming the codebook with P transforms, transforming a subset of the codebook with a transform, and forming the new codebook with results of each of the P transformations and the transformation.

38. The controller of claim 35, wherein the codebook is partitioned into M parts, where M is an integer value, and wherein the adaptation unit extends the codebook by transforming each of the M parts of the codebook with a transform, and forming the new codebook with results of the transformation of each of the M parts.

39. The controller of claim 35, wherein the codebook is partitioned into M parts, where M is an integer value, and wherein the adaptation unit extends the codebook by applying at least one transform to codewords in at least one part of the codebook, and applying a zero transform to remaining parts of the codebook.