CQI and rank prediction for list sphere decoding and ML MIMO receivers

• US 20070010957A1
• Filed: 05/25/2006
• Published: 01/11/2007
• Est. Priority Date: 06/01/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Sampath, Hemanth, Kadous, Tamer
• Granted Patent: US 8,971,461 B2
• Time in Patent Office: Days
• US Class Current: 702/57
• CPC Class Codes: H04B 1/1027 assessing signal quality or detecting noise/interference for the received signal
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/063 Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection
• CPC Class Codes: H04B 7/0632 Channel quality parameters, e.g. channel quality indicator [CQI]
• CPC Class Codes: H04B 7/12 Frequency diversity
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0656 Cyclotomic systems, e.g. Bell Labs Layered Space-Time [BLAST]
• CPC Class Codes: H04L 1/0675 characterised by the signaling
• CPC Class Codes: H04L 2025/03426 transmission using multiple-input and multiple-output channels
• CPC Class Codes: H04L 25/03242 Methods involving sphere decoding

Abstract

Systems and methodologies are described that facilitate integrating a list-sphere decoding design in a multiple input-multiple output (MIMO wireless communication environment. According to various aspects, optimal rank selection and CQI computation for an optimal rank can be performed in conjunction with a non-linear receiver, such as a maximum life (ML) MMSE receiver, a non-linear receiver with a list-sphere decoder, and the like. Optimal rank selection can be performed using a maximum rank selection protocol, a channel capacity-based protocol, or any other suitable protocol that facilitates rank selection, and CQI information can be generated based in part on effective SNRs determined with regard to a selected optimal rank.

Claims

1. A method of calculating rank in a non-linear receiver in a user device in a wireless communication environment, comprising:

receiving a transmission signal at a non-linear receiver;

determining a rank for one or more layers of the transmission signal; and

selecting a layer with an optimum rank that maximizes channel efficiency for transmissions.

2. The method of claim 1, further comprising employing a list-sphere decoding algorithm to decode the received signal transmission.

3. The method of claim 2, further comprising employing a QR-decomposition-based rank selection protocol to determine rank.

4. The method of claim 3, further com pnsing generating at least one subm atrix for each of the one or more layers.

5. The method of claim 4, further comprising determining a transmission capacity for each of the at least one submatrices and averaging capacities for each layer.

6. The method of claim 5, further comprising identifying a rank for a layer with a highest average capacity.

7. The method of claim 6, further comprising calculating a CQI and feeding back the CQI and rank information using a reverse link control channel.

8. The method of claim 2, further comprising performing a maximum rank selection protocol to determine rank.

9. The method of claim 8, further comprising calculating a spectral efficiency each of the one or more layers and averaging the spectral efficiency over a plurality of received tones.

10. The method of claim 9, further comprising identifying a rank for a layer with a highest average spectral efficiency.

11. The method of claim 10, further comprising calculating a CQI and feeding back the CQI and rank information over a reverse link control channel.

12. The method of claim 1, wherein the non-linear receiver is a maximum life (ML) minimum mean-squared error (MMSE) non-linear receiver.

13. The method of claim 1, wherein the wireless communication environment is a multiple input-multiple output (MIMO) single code word (SWC) wireless communication environment.

14. An apparatus that facilitates calculating rank in a non-linear receiver in a user device in a wireless communication environment, comprising:

a non-linear receiver that receives a signal with multiple layers;

a memory that stores information related to rank calculation algorithms; and

a processor coupled to the memory that employs a rank calculation algorithm to determine an optimum rank for at least one transmission layer in the received signal.

15. The apparatus of claim 14, the non-linear receiver employs a list-sphere decoding protocol to decode the received signal.

16. The apparatus of claim 15, further comprising a capacity mapping component that evaluates transmission capacity for at least one submatrix of at least one received layer.

17. The apparatus of claim 16, further comprising a rank evaluation component that identifies an optimal rank associated with a received layer having a highest average transmission capacity.

18. The apparatus of claim 15, wherein the processor generates a CQI report for transmission over a reverse link control channel and appends a 2-bit optimal rank identifier thereto.

19. The apparatus of claim 15, wherein the processor evaluates spectral efficiency for at least one layer of the received signal and averages the spectral efficiency over a plurality of tones associated with the received signal.

20. The apparatus of claim 19, wherein the processor generates a CQI report based at least in part on the average spectral efficiency.

21. The apparatus of claim 20, wherein the processor appends rank information comprising the highest rank of associated with received layers to the CQI report for transmission over a reverse link control channel.

22. A wireless communication apparatus, comprising:

means for performing a non-linear decoding protocol on a received multiple-layer signal in a user device;

means for determining an optimal rank associated with at least one of the layers of the received signal; and

means for transmitting information related to the optimal rank with CQI information over a reverse link control channel.

23. The apparatus of claim 22, further comprising means for performing a list-sphere decoding protocol to decode the received signal.

24. The apparatus of claim 22, further comprising means for generating a plurality of submatrices for each layer of the received signal and capacity mapping the submatrices.

25. The apparatus of claim 24, further comprising means for determining an effective signal-to-noise ratio (SNR) for each submatrix.

26. The apparatus of claim 25, further comprising means for generating CQI information related to the received signal based at least in part on the effective SNR of a layer having the optimal rank.

27. The apparatus of claim 22, the means for transmitting transmits a CQI and rank information over the reverse link control channel approximately every 5 ms.

28. A computer-readable medium having stored thereon computer-executable instructions for:

employing a non-linear decoding protocol to decode a received multiple-layer signal in a user device;

identifying an optimal rank associated with at least one of the layers of the received signal;

generating CQI information for the received signal based at least in part on the identified rank; and

transmitting CQI and rank information over a reverse link control channel.

29. The computer-readable medium of claim 28, further comprising instructions for performing a list-sphere decoding protocol to decode the received signal.

30. The computer-readable medium of claim 28, further comprising instructions for generating a plurality of submatrices for each layer of the received signal and capacity mapping the submatrices.

31. The computer-readable medium of claim 30, further comprising instructions for determining an effective signal-to-noise ratio (SNR) for each submatrix.

32. The computer-readable medium of claim 31, further comprising instructions for generating the CQI information based at least in part on the effective SNR of a layer having the optimal rank.

33. The computer-readable medium of claim 28, further comprising instructions for transmitting CQI and rank information over the reverse link control channel approximately every 5 ms.

34. A processor that executes instructions for increasing throughput in a wireless communication environment, the instructions comprising:

employing a non-linear decoding protocol to decode a received multiple-layer signal in a user device;

identifying an optimal rank associated with at least one of the layers of the received signal;

generating CQI information for the received signal based at least in part on the identified rank; and

transmitting CQI and rank information over a reverse link control channel.

35. The processor of claim 34, the instructions further comprising performing a list-sphere decoding protocol to decode the received signal.

36. The processor of claim 34, the instructions further comprising generating a plurality of submatrices for each layer of the received signal and capacity mapping the submatrices.

37. The processor of claim 36, the instructions further comprising determining an effective signal-to-noise ratio (SNR) for each submatrix.

38. The processor of claim 37, the instructions further comprising generating the CQI information based at least in part on the effective SNR of a layer having the optimal rank.

39. The processor of claim 34, the instructions further comprising transmitting CQI and rank information over the reverse link control channel approximately every 5 ms.