BEAMFORMING METHOD USING MULTIPLE ANTENNAS

• US 20100265853A1
• Filed: 07/16/2008
• Published: 10/21/2010
• Est. Priority Date: 12/18/2007
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute, Samsung Electronics Co. Ltd.
• Original Assignee: Electronics and Telecommunications Research Institute, Samsung Electronics Co. Ltd.
• Inventors: Song, Young Seog, Kwon, Dong Seung
• Granted Patent: US 8,774,086 B2
• Time in Patent Office: Days
• US Class Current: 370/280
• CPC Class Codes: H01Q 3/2647 Retrodirective arrays
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A mobile station includes a plurality of mobile station antennas that receive at least one independent training signal from a plurality of base station antennas, and estimates a downlink channel formed by each of a plurality of base station antennas and each of the mobile station antennas by using the at least one independent training signal. The mobile station generates a beam vector by using the downlink channel, and forms transmission beams in the plurality of mobile station antennas for transmitting a signal to an uplink.

Claims

1. A beamforming method comprising:

receiving at least one training signal from a plurality of base station antennas by using a plurality of mobile station antennas;

estimating downlink channels formed by the plurality of base station antennas and the plurality of mobile station antennas by using the at least one training signal;

generating a beam vector by using the downlink channels formed by the respective base station antennas and the respective mobile station antennas; and

beamforming by applying the beam vector to the plurality of mobile stations.

2. The beamforming method of claim 1, wherein the generating of the beam vector comprises:

selecting one base station antenna that forms a downlink channel with the maximum gain from among the plurality of base station antennas; and

generating the beam vectors by using a plurality of phases that respectively correspond to downlink channels formed by the one base station and the plurality of mobile station antennas.

3. The beamforming method of claim 2, wherein the beam vector has a plurality of beam coefficients that respectively correspond to the plurality of mobile stations, and each of the plurality of beam coefficients has the same gain.

4. The beamforming method of claim 3, wherein each phase of the plurality of beam coefficients corresponds to an inverse number of each of the plurality of phases.

5. The beamforming method of claim 4, wherein the beamforming comprises:

generating a plurality of beam signals by respectively applying the plurality of beam coefficients to a baseband signal;

generating a plurality of beam signals in a wireless band by frequency-converting the plurality of beam signals into wireless band signals; and

beamforming by respectively applying the beam signals in the wireless band to the plurality of mobile stations.

6. The beamforming method of claim 3, wherein the phases of the plurality of beam coefficients respectively correspond to a difference between the phase of a downlink channel formed by one of the plurality of mobile station antennas and the one base station antenna and each of the plurality of phases.

7. The beamforming method of claim 6, wherein the beamforming comprises:

generating a plurality of beam signals by respectively applying the plurality of beam coefficients to the wireless band signals; and

beamforming by respectively applying the plurality of beam signals to the respective mobile station antennas.

8. The beamforming method of claim 1, wherein the generating of the beam vector comprises:

generating a plurality of candidate beam vectors that respectively include a plurality of beam coefficients that respectively correspond to the plurality of mobile station antennas;

calculating a plurality of gains that respectively correspond to the plurality of candidate beam vectors by using the plurality of candidate beam vectors and downlink channels formed by the respective base station antennas and the respective mobile station antennas;

detecting a gain having the maximum gain from among the plurality of gains; and

generating the beam vector by selecting one beam vector that corresponds to the maximum gain from among the plurality of candidate beam vectors,

wherein the number of the plurality of candidate beam vectors corresponds to the number of the plurality of mobile station antennas.

9. The beamforming method of claim 8, wherein the phase of each of the plurality of beam coefficients is proportional to an index of each candidate beam vector and an index of a mobile station that corresponds to the beam coefficient, and

a gain of each of the plurality of beam coefficients corresponds to an inverse number of a square root of the number of the plurality of mobile station antennas.

10. The beamforming method of claim 1, wherein the generating of the beam vector comprises generating the beam vector with a random-generated beam vector or a beam vector that has been applied to the plurality of mobile station antennas for previous beamforming when moving speed of the mobile station is greater than a reference speed.

11. A beamforming method comprising:

receiving a training signal from one base station by using a plurality of mobile station antennas;

estimating downlink channels formed by the one base station antenna and the plurality of mobile station antennas by using the training signal;

generating a beam vector by using the downlink channel; and

beamforming by applying the beam vector to the plurality of mobile station antennas.

12. The beamforming method of claim 11, wherein the generating of the beam vector comprises

generating the beam vector by using a plurality of phases that respectively correspond to the downlink channels,

wherein the beam vector includes a plurality of beam coefficients that respectively correspond to the respective mobile station antennas, and

the plurality of beam coefficients respectively have the same gain.

13. The beamforming method of claim 12, wherein the phase of each of the plurality of beam coefficients corresponds to an inverse number of each of the plurality of phases.

14. The beamforming method of claim 13, wherein the beamforming comprises:

generating a plurality of beam signals by respectively applying the plurality of beam coefficients to a baseband signal;

generating a plurality of beam signals in a wireless band by frequency-converting the plurality of beam signals to wireless band signals; and

beamforming by respectively applying the plurality of beam signals in the wireless band to the plurality of mobile station antennas.

15. The beamforming method of claim 12, wherein each phase of the plurality of beam coefficients corresponds to a difference between the phase of a downlink channel formed by one of the plurality of mobile station antennas and the one base station antenna and each of the plurality of phases.

16. The beamforming method of claim 15, wherein the beamforming comprises:

generating a plurality of beam signals by respectively applying the plurality of beam coefficients to a wireless band signal; and

beamforming by respectively applying the plurality of beam signals to the respective mobile station antennas.

17. The beamforming method of claim 11, wherein the generating of the beam vector comprises generating the beam vector with a random-generated beam vector or a beam vector that has been applied to the plurality of mobile station antennas for previous beamforming when moving speed of the mobile station is greater than a reference speed.

18. A mobile station comprising:

a plurality of antennas configured to receive a training signal from a base station;

a downlink channel estimator configured to estimate downlink channels formed by the base station and the plurality of antennas using the training signal;

a beam vector generator configured to generate a beam vector by using the downlink channel; and

an uplink beamforming unit configured to beamform by applying the beam vector to the plurality of mobile station antennas.

19. The mobile station of claim 18, wherein the beam vector generator generates of the beam vector by using a plurality of phases that respectively correspond to the downlink channels;

wherein the beam vector includes a plurality of beam coefficients that respectively correspond to the respective mobile station antennas, and the plurality of beam coefficients respectively have the same gain.

20. The mobile station of claim 18, wherein the uplink beamforming unit is configured to:

generate a plurality of beam signals by respectively applying the plurality of beam coefficients to a baseband signal;

generate a plurality of beam signals in a wireless band by frequency-converting the plurality of beam signals to wireless band signals; and

beamform by respectively applying the plurality of beam signals in the wireless band to the plurality of mobile station antennas.