Method and system for analog beamforming in wireless communication systems

• US 20090058724A1
• Filed: 09/05/2007
• Published: 03/05/2009
• Est. Priority Date: 09/05/2007
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Xia, Pengfei, Niu, Huaning, Ngo, Chiu
• Granted Patent: US 7,714,781 B2
• Time in Patent Office: Days
• US Class Current: 342/368
• CPC Class Codes: H01Q 3/2605 Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays

Abstract

A method and system for analog beamforming in wireless communication system, is provided. Analog beamforming coefficients are constructed by performing an iterative beam acquisition process based on beam search training, and determining optimized beamforming weighting coefficients based on the iterative beam acquisition process.

Claims

1. A method of analog beamforming in a wireless communication system, comprising the steps of:

constructing analog beamforming coefficients by;

performing an iterative beam acquisition process based on beam search training; and

determining optimized beamforming weighting coefficients based on the iterative beam acquisition process, wherein each iteration includes estimating analog beamforming coefficients until the beamforming coefficients converge.

2. The method of claim 1 wherein determining optimized beamforming weighting coefficients includes determining optimized beamforming phase weighting coefficients based on the iterative beam acquisition process, wherein each iteration includes estimating receive and transmit analog beamforming coefficients alternatively, until the receive and transmit beamforming coefficients converge.

3. The method of claim 2 wherein the step of constructing the analog beamforming coefficients further includes performing an iterative process that essentially optimizes the analog transmit beamforming coefficients from initial values by finding interim receive beamforming coefficients, finding interim transmit beamforming coefficients, wherein at a terminating iteration, optimized transmit and receive beamforming coefficients are obtained.

4. The method of claim 2 wherein performing beam search training further includes:

determining an estimate of an equivalent channel based on a preamble training sequence.

5. The method of claim 4 wherein determining optimized beamforming weighting coefficients further comprises:

selecting initial receive beamforming coefficient values; and

performing an iterative process that essentially optimizes the analog receive beamforming coefficients from initial values, as a function of the estimated channel.

6. The method of claim 5 wherein the iterative process further includes iteratively optimizing the analog receive beamforming coefficients from initial values, as a function of the estimated channel and analog transmit beamforming coefficients.

7. The method of claim 4 wherein determining optimized beamforming weighting coefficients further comprises:

selecting initial transmit beamforming coefficient values; and

performing an iterative process that essentially optimizes the analog transmit beamforming coefficients from initial values, as a function of the estimated channel.

8. The method of claim 7 wherein the iterative process further includes iteratively optimizing the analog receive beamforming coefficients from initial values, as a function of the estimated channel and analog receive beamforming coefficients.

9. The method of claim 4 wherein determining the beamforming coefficients further includes determining the analog transmit beamforming coefficients and the analog receive beamforming coefficients by performing an iterative process that essentially optimizes the analog transmit beamforming coefficients and the analog receive beamforming coefficients, from initial values, as a function of the estimated channel.

10. The method of claim 9, wherein the iterative process further comprises the steps of:

(a) selecting an initial estimate of the analog transmit beamforming coefficients;

(b) estimating an equivalent channel B based on the estimated channel and the estimated analog transmit beamforming coefficients;

(c) estimating analog receive beamforming coefficients from the estimated equivalent channel B;

(d) estimating an equivalent channel A based on the estimated channel and the estimated analog receive beamforming coefficients;

(e) estimating analog transmit beamforming coefficients from the estimated equivalent channel A; and

(f) repeating the steps (b) through (e) until the analog transmit beamforming coefficients and the analog receive beamforming coefficients converge.

11. The method of claim 10, wherein the iterative process further comprises the steps of:

(a) selecting an initial estimate of the analog receive beamforming coefficients;

(b) estimating an equivalent channel A based on the estimated channel and the estimated analog receive beamforming coefficients;

(c) estimating analog transmit beamforming coefficients from the estimated equivalent channel A;

(d) estimating an equivalent channel B based on the estimated channel and the estimated analog transmit beamforming coefficients;

(e) estimating analog receive beamforming coefficients from the estimated equivalent channel B; and

(f) repeating the steps (b) through (e) until the analog transmit beamforming coefficients and the analog receive beamforming coefficients converge.

12. The method of claim 2 wherein determining beamforming coefficients further includes determining analog beamforming coefficients for MIMO OFDM communication.

13. The method of claim 2 further including communicating information over a channel by analog beamforming using the analog transmit beamforming coefficients and the analog receive beamforming coefficients.

14. The method of claim 13 wherein the step of communicating the information over the channel comprises the steps of:

applying the analog transmit beamforming coefficients to analog information representing data symbols, to obtain weighted information;

transmit-beamforming the weighted information over multiple paths in a wireless channel;

receiving the information signals;

applying the analog receive beamforming coefficients to the received information signals to obtain weighted information signals; and

recovering received data symbols from the weighted information signals.

15. The method of claim 1 wherein performing beam search training further includes:

transmitting a training sequence over a wireless channel;

receiving the training sequence; and

estimating beamforming coefficients based on the received training sequence.

16. A wireless receiver, comprising:

an estimation module configured for beam search training; and

an analog beamforming module configured for beamforming estimation based on receiver side antenna diversity and the beam search training, wherein beamforming estimation includes iterative beam acquisition process for finding optimized beamforming vectors comprising phase weighting coefficients, each iteration including estimating receive beamforming, wherein at a terminating iteration optimized receive beamforming coefficients are obtained.

17. The wireless receiver of claim 16 wherein the estimation module is configured for:

receiving a training sequence over a wireless; and

estimating receive beamforming coefficients based on the received training sequence.

18. The wireless receiver of claim 16 wherein the analog beamforming module is further configured for performing an iterative process that essentially optimizes the analog receive beamforming coefficients from initial values by finding interim receive beamforming coefficients, until the receive beamforming coefficients converge with transmit beamforming coefficients at a terminating iteration.

19. The wireless receiver of claim 18 wherein the estimation module is configured for determining an estimate of an equivalent channel based on a preamble training sequence.

20. The wireless receiver of claim 19 wherein the beamforming module is further configured for selecting initial receive beamforming coefficient values, and performing an iterative process that essentially optimizes the analog receive beamforming coefficients from initial values, as a function of the estimated channel.

21. The wireless receiver of claim 20 wherein the beamforming module is further configured for iteratively optimizing the analog receive beamforming coefficients from initial values, as a function of the estimated channel and analog transmit beamforming coefficients.

22. The wireless receiver of claim 21 wherein the beamforming module is further configured for performing said iterative process by:

(a) selecting an initial estimate of the analog receive beamforming coefficients;

(b) estimating an equivalent channel A based on the estimated channel and the estimated analog receive beamforming coefficients;

(c) estimating an equivalent channel B based on the estimated channel and estimated analog transmit beamforming coefficients;

(d) estimating analog receive beamforming coefficients from the estimated equivalent channel B; and

(e) repeating the steps (b) through (d) until the analog transmit beamforming coefficients and the analog receive beamforming coefficients converge.

23. The wireless receiver of claim 16 wherein the beamforming module determines analog beamforming coefficients for MIMO OFDM communication.

24. A wireless transmitter, comprising:

an estimation module configured for beam search training; and

an analog beamforming module configured for beamforming estimation based on transmitter side antenna diversity and the beam search training, wherein beamforming estimation includes iterative beam acquisition process for finding optimized beamforming vectors comprising phase weighting coefficients, each iteration including estimating transmit beamforming coefficients, wherein at a terminating iteration optimized transmit beamforming coefficients are obtained.

25. The wireless transmitter of claim 24 wherein the estimation module is configured for:

receiving a training sequence over a wireless; and

estimating transmit beamforming coefficients based on the received training sequence.

26. The wireless transmitter of claim 24 wherein the analog beamforming module is further configured for performing an iterative process that essentially optimizes the analog transmit beamforming coefficients from initial values by finding interim transmit beamforming coefficients, until the transmit beamforming coefficients converge with receive beamforming coefficients at a terminating iteration.

27. The wireless transmitter of claim 25 wherein the estimation module is configured for determining an estimate of an equivalent channel based on a preamble training sequence.

28. The wireless transmitter of claim 26 wherein the beamforming module is further configured for selecting initial transmit beamforming coefficient values, and performing an iterative process that essentially optimizes the analog transmit beamforming coefficients from initial values, as a function of the estimated channel.

29. The wireless transmitter of claim 27 wherein the beamforming module is further configured for iteratively optimizing the analog transmit beamforming coefficients from initial values, as a function of the estimated channel and analog receive beamforming coefficients.

30. The wireless transmitter of claim 28 wherein the beamforming module is further configured for performing said iterative process by:

(a) selecting an initial estimate of the analog transmit beamforming coefficients;

(b) estimating an equivalent channel B based on the estimated channel and the estimated analog transmit beamforming coefficients;

(c) estimating an equivalent channel A based on the estimated channel and estimated analog receive beamforming coefficients;

(d) estimating analog transmit beamforming coefficients from the estimated equivalent channel A; and

(e) repeating the steps (b) through (d) until the analog transmit beamforming coefficients and the analog receive beamforming coefficients converge.

31. The wireless transmitter of claim 24 wherein the beamforming module determines analog beamforming coefficients for MIMO OFDM communication.