Method and system for pre-equalization in a single weight spatial multiplexing MIMO system

• US 20060072683A1
• Filed: 06/30/2005
• Published: 04/06/2006
• Est. Priority Date: 10/06/2004
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Kent, Mark, Roux, Pieter, Landau, Uri M., Erceg, Vinko, Rooyen, Pieter Van
• Granted Patent: US 8,098,776 B2
• Time in Patent Office: Days
• US Class Current: 375/267
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0697 using spatial multiplexing
• CPC Class Codes: H04L 1/0656 Cyclotomic systems, e.g. Bell Labs Layered Space-Time [BLAST]
• CPC Class Codes: H04L 2025/03426 transmission using multiple-input and multiple-output channels
• CPC Class Codes: H04L 2025/03726 Switching between algorithms
• CPC Class Codes: H04L 2025/03808 Transmission of equaliser coefficients
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0214 of a single coefficient
• CPC Class Codes: H04L 25/0244 with inversion
• CPC Class Codes: H04L 25/025 using least-mean-square [LMS] method
• CPC Class Codes: H04L 25/03019 adaptive, i.e. capable of adjustment during data reception
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end

Abstract

Certain aspects of the method may comprise receiving a plurality of spatially multiplexed communication signals from a plurality of transmit antennas at a base station. A plurality of vectors of baseband combined channel estimates may be generated based on phase rotation of the received plurality of spatially multiplexed communication signals. A plurality of pre-equalization weights may be generated based on the generated plurality of vectors of baseband combined channel estimates. The received plurality of spatially multiplexed communication signals may be modified based on the generated plurality of pre-equalization weights. At least a portion of the generated plurality of pre-equalization weights may be fed back to the base station for modifying subsequently transmitted spatially multiplexed communication signals which are transmitted from at least a portion of the plurality of transmit antennas at the base station.

Claims

1. A method for processing signals in a communication system, the method comprising:

receiving a plurality of spatially multiplexed communication signals from a plurality of transmit antennas at a base station;

generating a plurality of vectors of baseband combined channel estimates based on phase rotation of said received plurality of spatially multiplexed communication signals;

generating a plurality of pre-equalization weights based on said generated plurality of vectors of baseband combined channel estimates;

modifying said received plurality of spatially multiplexed communication signals based on said generated plurality of pre-equalization weights; and

feeding back at least a portion of said generated plurality of pre-equalization weights to said base station for modifying subsequently transmitted spatially multiplexed communication signals which are transmitted from at least a portion of said plurality of transmit antennas at said base station.

2. The method according to claim 1, further comprising generating said plurality of pre-equalization weights based on least mean squares (LMS) algorithm.

3. The method according to claim 1, further comprising generating said plurality of pre-equalization weights based on recursive least squares (RLS) algorithm.

4. The method according to claim 1, further comprising generating said plurality of pre-equalization weights based on direct matrix inversion.

5. The method according to claim 1, further comprising generating said plurality of pre-equalization weights based on a cost function.

6. The method according to claim 5, further comprising modifying at least one of a plurality of parameters in said cost function.

7. The method according to claim 1, further comprising generating said plurality of pre-equalization weights periodically.

8. The method according to claim 1, further comprising generating said plurality of pre-equalization weights continuously.

9. The method according to claim 1, wherein said feedback occurs via an uplink channel.

10. The method according to claim 1, further comprising spatially demultiplexing said received plurality of spatially multiplexed communication signals.

11. A system for processing signals in a communication system, the system comprising:

a plurality of receive antennas that receive a plurality of spatially multiplexed communication signals from a plurality of transmit antennas;

a channel estimator that generates a plurality of vectors of baseband combined channel estimates based on phase rotation of said received plurality of spatially multiplexed communication signals;

at least one processor that generates a plurality of pre-equalization weights based on said generated plurality of vectors of baseband combined channel estimates;

said at least one processor modifies said received plurality of spatially multiplexed communication signals based on said generated plurality of pre-equalization weights; and

said at least one processor feeds back at least a portion of said generated plurality of pre-equalization weights to said base station for modifying subsequently transmitted spatially multiplexed communication signals which are transmitted from at least a portion of said plurality of transmit antennas at said base station.

12. The system according to claim 11, wherein said at least one processor generates said plurality of pre-equalization weights based on least mean squares (LMS) algorithm.

13. The system according to claim 11, wherein said at least one processor generates said plurality of pre-equalization weights based on recursive least squares (RLS) algorithm.

14. The system according to claim 11, wherein said at least one processor generates said plurality of pre-equalization weights based on direct matrix inversion.

15. The system according to claim 11, wherein said at least one processor generates said plurality of pre-equalization weights based on a cost function.

16. The system according to claim 15, wherein said at least one processor modifies at least one of a plurality of parameters in said cost function.

17. The system according to claim 11, wherein said at least one processor generates said plurality of pre-equalization weights periodically.

18. The system according to claim 11, wherein said at least one processor generates said plurality of pre-equalization weights continuously.

19. The system according to claim 11, wherein said feedback occurs via an uplink channel.

20. The system according to claim 11, wherein said at least one processor spatially demultiplexes said received plurality of spatially multiplexed communication signals.