MIMO Transmission with Rank Adaptation for Multi-Gigabit 60 GHz Wireless

• US 20110222616A1
• Filed: 03/11/2011
• Published: 09/15/2011
• Est. Priority Date: 03/11/2010
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Laboratories America Inc (NEC Corporation)
• Inventors: Jiang, Meilong, Yue, Guosen
• Granted Patent: US 8,571,127 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0486 taking channel rank into account
• CPC Class Codes: H04B 7/0617 for beam forming
• 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 7/0639 Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection
• CPC Class Codes: H04B 7/0689 using different transmission schemes, at least one of them being a diversity transmission scheme
• CPC Class Codes: H04L 2025/03426 transmission using multiple-input and multiple-output channels
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0242 using matrix methods
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end

Abstract

A wireless system includes a transmitter with a baseband processor responsive to groups of transmitter antenna arrays for communicating over directional beams; and a receiver with a baseband processor responsive to groups of receiver antenna rays for communicating with the transmitter over the directional beams, the receiver including both a rank adaptation providing a transmit mode feedback to the transmitter and a blind beamforming providing a transmit beamformer index feedback to the transmitter and receiver groups of antenna arrays.

Claims

1. A wireless system comprising:

a transmitter with a baseband processor responsive to groups of transmitter antenna arrays for communicating over directional beams; and

a receiver with a baseband processor responsive to groups of receiver antenna arrays for communicating with said transmitter over said directional beams, said receiver including both a rank adaptation providing a transmit mode feedback to said transmitter and a blind beamforming providing a transmit beamformer index feedback to said transmitter and receiver groups of antenna arrays.

2. The system of claim 1, wherein said blind beamforming comprises a stochastic gradient algorithm based blind beam forming.

3. The system of claim 1, wherein said blind beamforming comprises generating enhanced perturbation vectors.

4. The system of claim 3, wherein said blind beamforming comprises iteration to generate new beamformers responsive to said perturbation vectors and a current beam beamformer.

5. The system of claim 4, wherein said blind beamforming comprises determining a received power for all combination of transmitter and receiver antenna beamformers responsive to said new beamformers.

6. The system of claim 5, wherein said blind beamforming comprises determining optimal transmit and receive beamformers for updating said current beamformer.

7. The system of claim 1, wherein said rank adaptation is responsive to a composite channel estimation with reduced complexity and higher accuracy from improved signal-to-noise-ratio contributed by joint effect of transmitter-receiver beamforming.

8. The system of claim 1, wherein said rank adaptation comprises a capacity evaluation responsive to at least one of composite channel gain and capacity prediction obtained at said receiver, said transmission being adaptively chosen from one of a high rank spatial multiplexing and a rank−

1 beamforming whichever gives higher throughput.

9. The system of claim 8, where said capacity for said high rank spatial multiplexing and said rank1 beamforming is respectively given by

10. The system of claim 9, wherein said optimal transmission follows from the relationship C_OPT=max(C_rankM,C_rank1).

13. The method of claim 1, wherein said blind beamforming comprises generating enhanced perturbation vectors.

14. The method of claim 13, wherein said blind beamforming comprises iteration to generate new beamformers responsive to said perturbation vectors and a current beam beamformer.

15. The method of claim 14, wherein said blind beamforming comprises determining a received power for all combination of transmitter and receiver antenna beamformers responsive to said new beamformers.

16. The method of claim 15, wherein said blind beamforming comprises determining optimal transmit and receive beamformers for updating said current beamformer.

21. The system of claim 9, wherein said optimal capacity for said high rank spatial multiplexing comprises a spectral efficiency evaluation based on a practical receiver filtering responsive to a composite channel gain obtained at said receiver, said transmission being chosen from one of a high rank spatial multiplexing and a rank−

1 beamforming whichever gives a higher throughput.

22. The system of claim 21, where said practical receiver filtering comprises one of a minimum mean square error (MMSE) receiver, a zero-forcing receiver, or any other practical receivers.

11. A method for wireless communication comprising the steps of:

communicating over directional beams by a transmitter with a baseband processor responsive to groups of transmitter antenna arrays for; and

communicating with said transmitter over said directional beams by a receiver with a baseband processor responsive to groups of receiver antenna arrays, said receiver including both a rank adaptation providing a transmit mode feedback to said transmitter and a blind beamforming providing a transmit beamformer index feedback to said transmitter and receiver groups of antenna arrays.

12. The method of claim 11, wherein said blind beamforming comprises a stochastic gradient algorithm based blind beam forming.

17. The method of claim 11, wherein said rank adaptation is responsive to a composite channel estimation with reduced complexity and higher accuracy from improved signal-to-noise-ratio contributed by joint effect of transmitter-receiver beamforming.

18. The method of claim 11, wherein said rank adaptation comprises a capacity evaluation responsive to a composite channel gain obtained at said receiver, said transmission being adaptively chosen from one of a high rank spatial multiplexing and a rank−

1 beamforming whichever gives higher throughput.

19. The method of claim 18, where said capacity for said high rank spatial multiplexing and said rank1 beamforming is respectively given by

20. The method of claim 19, wherein said optimal transmission follows from the relationship C_OPT=max(C_rankM,C_rank1).

23. The method of claim 19, wherein said optimal capacity for said high rank spatial multiplexing comprises a spectral efficiency evaluation based on a practical receiver filtering responsive to a composite channel gain obtained at said receiver, said transmission being chosen from one of a high rank spatial multiplexing and a rank−

1 beamforming whichever gives a higher throughput.

24. The method of claim 23, where said practical receiver filtering comprises one of a minimum mean square error (MMSE) receiver, a zero-forcing receiver, or any other practical receivers.