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

• US 8,422,606 B2
• Filed: 12/15/2011
• Issued: 04/16/2013
• Est. Priority Date: 10/06/2004
• Status: Expired due to Fees

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Kent, Mark, Erceg, Vinko, Landau, Uri M, van Rooyen, Pieter, Roux, Pieter
• Primary Examiner(s): Payne, David C.
• Assistant Examiner(s): Perez, James M
• Application Number:
  US13/327,011
• Publication Number:
  US 20120087434A1
• Time in Patent Office: 488 Days
• Field of Search: 375/130, 375/140, 375/141, 375146-147, 375229-232, 375259-260, 375/267, 375/295, 375/296, 375/316, 375/346, 375/347, 375/354, 375/358
• US Class Current: 375/346
• 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, comprising:

generating a plurality of vectors of baseband combined channel estimates based on phase rotation of a received plurality of spatially multiplexed communication signals, said phase rotation being determined based on orthogonalization of channels associated with 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; and

feeding back a portion of said generated plurality of pre-equalization weights to a base station for modifying subsequently transmitted spatially multiplexed communication signals,

wherein at least one step of said method is performed by at least one hardware device.

2. The method according to claim 1, further comprising:

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

3. The method according to claim 2, further comprising:

modifying subsequently received spatially multiplexed communication signals based on a generated plurality of weights.

4. The method according to claim 2, further comprising:

spatially demultiplexing said received plurality of spatially multiplexed communication signals.

5. The method according to claim 1, further comprising:

generating said plurality of pre-equalization weights based on one or more of;

a least mean squares (LMS) algorithm, a recursive least squares (RLS) algorithm, a direct matrix inversion, and a second order statistical technique.

6. The method according to claim 1, wherein the step of generating a plurality of pre-equalization weights comprises:

generating said plurality of pre-equalization weights based on a cost function.

7. The method according to claim 6, further comprising:

modifying at least one of a plurality of parameters in said cost function.

8. The method according to claim 1, wherein the step of generating a plurality of pre-equalization weights comprises:

generating said plurality of pre-equalization weights periodically or continuously.

9. The method according to claim 1, wherein the step of feeding back comprises:

feeding back said portion via an uplink channel.

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

generating a plurality of vectors of baseband combined channel estimates based on phase rotation of a received plurality of spatially multiplexed communication signals, said phase rotation being determined based on orthogonalization of channels associated with said received plurality of spatially multiplexed communication signals;

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

feeding back a portion of said generated plurality of pre-equalization weights to a base station for modifying subsequently transmitted spatially multiplexed communication signals; and

modifying a phase or an amplitude of subsequently received spatially multiplexed communication signals based on said generated plurality of phase and amplitude values,

wherein at least one step of said method is performed by at least one hardware device.

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

one or more circuits for use in a receiver, said one or more circuits being configured to;

generate a plurality of vectors of baseband combined channel estimates based on phase rotation of a received plurality of spatially multiplexed communication signals, said phase rotation being determined based on orthogonalization of channels associated with said received plurality of spatially multiplexed communication signals;

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

feed back a portion of said generated plurality of pre-equalization weights to a base station for modifying subsequently transmitted spatially multiplexed communication signals.

12. The system according to claim 11, wherein said one or more circuits are further configured to receive said plurality of spatially multiplexed communication signals from a plurality of transmit antennas at said base station.

13. The system according to claim 12, wherein said one or more circuits are further configured to modify subsequently received spatially multiplexed communication signals based on a generated plurality of weights.

14. The system according to claim 12, wherein said one or more circuits are further configured to spatially demultiplex said received plurality of spatially multiplexed communication signals.

15. The system according to claim 11, wherein said one or more circuits are further configured to generate said plurality of pre equalization weights based on one or more of:

a least mean squares (LMS) algorithm, a recursive least squares (RLS) algorithm, a direct matrix inversion, and a second order statistical technique.

16. The system according to claim 11, wherein said one or more circuits are further configured to generate said plurality of pre-equalization weights based on a cost function.

17. The system according to claim 16, wherein said one or more circuits are further configured to modify at least one of a plurality of parameters in said cost function.

18. The system according to claim 11, wherein said one or more circuits are further configured to generate said plurality of pre-equalization weights periodically or continuously.

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

20. The system according to claim 11, wherein said one or more circuits are further configured to modify a phase or an amplitude of subsequently received spatially multiplexed communication signals based on a generated plurality of phase and amplitude values, wherein said generated plurality of phase and amplitude values are generated based on said generated plurality of vectors of baseband combined channel estimates.