Performance based rank prediction for MIMO design

• US 9,148,256 B2
• Filed: 12/22/2004
• Issued: 09/29/2015
• Est. Priority Date: 07/21/2004
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Sampath, Hemanth, Kadous, Tamer
• Primary Examiner(s): TSE, YOUNG TOI
• Application Number:
  US11/021,791
• Publication Number:
  US 20060133521A1
• Time in Patent Office: 3,933 Days
• Field of Search: 375/221, 375/260, 375/265, 375/267, 375/299, 370/208, 370/210, 455/24, 455/500, 455/69, 455/101
• US Class Current: 1/1
• CPC Class Codes: H04B 7/0486 taking channel rank into account
• CPC Class Codes: H04L 1/0618 Space-time coding
• CPC Class Codes: H04L 5/0044 allocation of payload

Abstract

The performance of a Single Code Word (SCW) design with low complexity MMSE receiver & rank prediction is similar to the Multiple Code Word (MCW) design with successive interference cancellation (SIC). A method of rank prediction comprises calculating MIMO channel matrices corresponding to layer transmissions for each tone, calculating signal-to-noise ratios (SNRs) for each tone based on the MIMO channel matrices, mapping the SNR for each tone to generate effective SNRs for each layer transmission, selecting a highest packet format (PF) with an SNR threshold less than the effective SNR for each layer transmission, maximizing an over-all spectral efficiency based on the selected highest packet formats for each layer transmission, and selecting a rank based on maximizing an over-all spectral efficiency.

Claims

1. A method of rank prediction, comprising:

calculating MIMO channel matrices corresponding to layer transmissions for each tone;

calculating signal-to-noise ratios (SNRs) for each tone based on the MIMO channel matrices;

mapping the SNRs for each tone to generate effective SNRs for each layer transmission;

selecting a highest packet format (PF) with an SNR threshold less than the effective SNRs for each layer transmission;

selecting an absolute highest PF of the selected highest PF for each layer transmission;

selecting a rank based on the selected absolute highest PF; and

transmitting a ranking to a transmitting side which indicates the layer transmissions to select for transmission so as to maximize spectral efficiency.

2. The method of claim 1, further, comprising sending a quality indicator based on the selected rank.

3. The method of claim 2, wherein the quality indicator is Carrier-Quality-to-Interference (CQI).

4. The method of claim 3, wherein the quality indicator CQI is calculated as CQI({circumflex over (M)})=Quant [EffSNR_{{circumflex over (M)}}], where EffSNR is the effective SNRs of the selected rank.

5. The method of claim 1, wherein the number of the layer transmissions is four.

6. The method of claim 1, wherein the SNR for each tone is calculated as

7. The method of claim 1, wherein the mapping is unconstrained with respect to capacity.

8. The method of claim 1, wherein the selected rank {circumflex over (M)} is calculated as

9. A wireless communications device, comprising:

means for calculating MIMO channel matrices corresponding to layer transmissions for each tone;

means for calculating signal-to-noise ratios (SNRs) for each tone based on the MIMO channel matrices;

means for mapping the SNRs for each tone to generate effective SNRs for each layer transmission;

means for selecting a highest packet format (PF) with an SNR threshold less than the effective SNRs for each layer transmission;

means for selecting an absolute highest PF of the selected highest PF for each layer transmission;

means for selecting a rank based on the selected absolute highest PF; and

means for transmitting a ranking to a transmitting side which indicates the layer transmissions to select for transmission so as to maximize spectral efficiency.

10. The wireless communications device of claim 9, further comprising means for sending a quality indicator based on the selected rank.

11. The wireless communications device of claim 10, wherein the quality indicator is Carrier-Quality-to-Interference.

12. The wireless communications device of claim 9, wherein the number of the layer transmissions is at least two.

13. A processor programmed to execute a non-transitory computer-readable medium of a method of rank prediction to maximize spectral efficiency in a MIMO wireless communication system, the method comprising:

calculating MIMO channel matrices corresponding to layer transmissions for each tone;

calculating signal-to-noise ratios (SNRs) for each tone based on the MIMO channel matrices;

mapping the SNRs for each tone to generate effective SNRs for each layer transmission;

selecting a highest packet format (PF) with an SNRs threshold less than the effective SNRs for each layer transmission;

selecting an absolute highest PF of the selected highest PF for each layer transmission;

selecting a rank based on the selected absolute highest PF; and

transmitting a ranking to a transmitting side which indicates the layer transmissions to select for transmission so as to maximize spectral efficiency.

14. The processor of claim 13, wherein the method further comprises sending a quality indicator based on the selected rank.

15. The processor of claim 14, wherein the quality indicator is Carrier-Quality-to-Interference.

16. The processor of claim 13, wherein the number of the layer transmissions is at least two.

17. A non-transitory computer-readable medium embodying instructions executable by a processor for providing a method of rank prediction to maximize spectral efficiency in a MIMO wireless communication system, the method comprising:

calculating MINO channel matrices corresponding to layer transmissions for each tone;

calculating signal-to-noise ratios (SNRs) for each tone based on the MIMO channel matrices;

mapping the SNRs for each tone to generate effective SNRs for each layer transmission;

selecting a highest packet format (PF) with an SNR threshold less than the effective SNRs for each layer transmission;

selecting an absolute highest PF of the selected highest PF for each layer transmission;

selecting a rank based on the selected absolute highest PF; and

transmitting a ranking to a transmitting side which indicates the layer transmissions to select for transmission so as to maximize spectral efficiency.

18. The computer-readable medium of claim 17, wherein the method further comprises sending a quality indicator based on the selected rank.

19. The computer readable of claim 18, wherein the quality indicator is Carrier-Quality-to-Interference.

20. The computer readable of claim 17, wherein the number of the layer transmissions is at least two.

21. An apparatus for performing rank prediction, comprising:

a plurality of receiving circuits for receiving calculated MIMO channel matrices corresponding to layer transmissions for each tone and calculating signal-to-noise ratios (SNRs) for each tone based on the MIMO channel matrices;

a plurality of capacity mappers, coupled to the plurality of receivers, for mapping the SNRs for each tone to generate effective SNRs for each layer transmission;

at least one packet format (PF) selector, coupled to the plurality of capacity mappers, for selecting a highest PF with an SNR threshold less than the effective SNRs for each layer transmission; and

a decision unit, coupled to the at least one PF selector, for selecting an absolute highest PF of the selected highest PF for each layer transmission, selecting a rank based on the selected absolute highest PF, and outputting the rank for forwarding to a transmitting side which indicates the layer transmissions to select for transmission so as to maximize spectral efficiency.

22. The apparatus of claim 21, further comprising a select-and-quantize unit, coupled to the plurality of capacity mappers, for generating and sending a quality indicator based on the selected rank.

23. The apparatus of claim 22, wherein the quality indicator is Carrier-Quality-to-Interference (CQI).

24. The apparatus of claim 23, wherein the CQI is calculated as CQI({circumflex over (M)})=Quant[EffSNR_{{circumflex over (M)}}], where EffSNR is the effective SNRs of the selected rank.

25. The apparatus of claim 21, wherein the number of the layer transmissions is four.

26. The apparatus of claim 21, wherein the SNR for each tone is calculated as

27. The apparatus of claim 21, wherein the mapping is unconstrained with respect to capacity.

28. The apparatus of claim 21, wherein the selected rank {circumflex over (M)} is calculated as