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

• US 7,428,269 B2
• Filed: 05/31/2006
• Issued: 09/23/2008
• Est. Priority Date: 06/01/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Sampath, Hemanth, Kadous, Tamer
• Primary Examiner(s): Ghayour; Mohammad
• Assistant Examiner(s): Vlahos; Sophia
• Application Number:
  US11/445,098
• Publication Number:
  US 20060276212A1
• Time in Patent Office: 846 Days
• Field of Search: 370/329, 370/338, 370/341, 370/334, 375/267, 375/295, 375/299, 455/513
• US Class Current: 375/267
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0434 using multiple eigenmodes
• 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: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0028 Formatting
• 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
• CPC Class Codes: H04L 27/2626 Arrangements specific to the transmitter only
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals

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 likelihood (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 transceiver in a wireless communication transceiver, comprising:

receiving a transmission signal at a non-linear receiver;

generating submatrices from a transmission channel over which the transmission signal is received;

performing a Q-R decomposition on the submatrices and deriving respective upper triangle matrices;

determining an effective SNR for one or more possible transmission ranks;

determining a channel capacity metric for all possible ranks of the transmission signal; and

selecting a rank that maximizes channel capacity 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 identifying a rank with a highest average capacity.

4. The method of claim 3, further comprising calculating a channel quality indicator (CQI) and feeding back the CQI and rank information using a reverse link control channel.

5. The method of claim 1, wherein the non-linear receiver is a maximum likelihood based non-linear receiver.

6. The method of claim 1, wherein the wireless communication transceiver is a multiple input-multiple output (MIMO) single code word (SCW) wireless transceiver.

7. 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 generating submatrices from a transmission channel over which the transmission signal is received;

means for performing a Q-R decomposition on the submatrices and deriving respective upper triangle matrices;

means for determining an effective SNR for one or more possible transmission ranks;

means for determining a channel capacity metric for each possible rank of the received signal; and

means for transmitting information related to an optimal rank with channel quality indicator (CQI) information over a reverse link control channel.

8. The apparatus of claim 7, further comprising means for performing a list-sphere decoding protocol to decode the received signal.

9. The apparatus of claim 8, further comprising means for generating channel quality indicator (CQI) information related to the received signal based at least in part on the effective SNR of a layer having the optimal rank.

10. The apparatus of claim 7, the means for transmitting transmits a channel quality indicator (CQI) and rank information over the reverse link control channel approximately every 5 ms.

11. 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;

generating submatrices from a transmission channel over which the transmission signal is received;

performing a Q-R decomposition on the submatrices and deriving respective upper triangle matrices;

determining an effective SNR for one or more possible transmission ranks;

determining a channel capacity metric for all possible ranks of the transmission signal; and

selecting a rank that maximizes channel capacity for transmissions.

12. The computer-readable medium of claim 11, further comprising instructions for employing a list-sphere decoding algorithm to decode the received signal transmission.

13. The computer-readable medium of claim 12, further comprising instructions for determining a transmission capacity for each of the submatrices and averaging capacities for each rank.

14. The computer-readable medium of claim 13, further comprising instructions for identifying a rank with a highest average capacity.

15. The computer-readable medium of claim 14, further comprising instructions for calculating a channel quality indicator (CQI) and feeding back the CQI and rank information using a reverse link control channel.

16. A method of calculating rank in a non-linear transceiver in a wireless communication transceiver, comprising:

receiving a transmission signal at a non-linear receiver including a plurality of antennas;

generating submatrices from a transmission channel over which the transmission signal is received;

performing a Q-R decomposition on the submatrices and deriving respective upper triangle matrices;

determining an effective SNR for one or more possible transmission ranks, each of said ranks corresponding to a corresponding number of spatial streams mapped to said plurality of antennas;

determining a channel capacity metric for all possible ranks of the transmission signal; and

selecting a rank that maximizes channel capacity for transmissions.