Method for Selecting Antennas and Beams in MIMO Wireless LANs

• US 20090086690A1
• Filed: 11/21/2005
• Published: 04/02/2009
• Est. Priority Date: 09/30/2005
• Status: Active Grant

• Current Assignee: Freedom Patents LLC
• Original Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Inventors: Zhang, Jinyun, Molisch, Andreas F., Zhang, Hongyuan, Gu, Daqing
• Granted Patent: US 8,374,096 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0691 using subgroups of transmit antennas
• CPC Class Codes: H04B 7/0874 using subgroups of receive antennas
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 5/0023 Time-frequency-space

Abstract

A computer implemented method selects antennas in a multiple-input, multiple-output wireless local area network that includes multiple stations, and each station includes a set of antennas. Multiple consecutively transmitted sounding packets are received in a station. Each sounding packet corresponds to a different subset of the set of antennas. A channel matrix is estimated from the multiple consecutively transmitted sounding packets. A frame including a high throughput (HT) control field is sent to initiate a selecting of antennas, and a subset of antennas is selected according to the channel matrix.

Claims

1. A computer implemented method for selecting antennas in a multiple-input, multiple-output wireless local area network including a plurality of stations, each station includes a set of antennas, comprising the steps of:

receiving multiple transmitted sounding packets in a station, each sounding packet corresponding to a different subset of the set of antennas;

estimating a channel matrix for each subset of antennas;

sending a frame including a high throughput (HT) control field to initiate a selecting of antennas after estimating the channel matrix for each subset of antennas; and

selecting a subset of antennas according to the channel matrics.

2. The method of claim 1, in which the high throughput control field includes a link adaptation control (LAC) field, and the LAC field includes either an antenna/beam selection indicator (ASI) field.

3. The method of claim 1, in which the high throughput control field includes a MCS selection feedback (FB) field, and if an ASI field is set to 1 or if an MRS field is set to “

111”

, then the MFB field is used for antenna/beam selection/transmitter beam forming control (ASBFC).

4. The method of claim 3, in which ASBFC field includes a command subfield and a data subfield.

5. The method of claim 4, in which the data subfield indicates a number of the multiple sounding packets.

6. The method of claim 4, in which the data subfield indicates a number of remaining sounding packets to be received.

7. The method of claim 4, in which the data subfield indicates a first of the multiple sounding packets.

8. The method of claim 4, in which the data subfield indicates a last of the multiple sounding packets.

9. The method of claim 1, in which the selected antennas are receive antennas.

10. The method of claim 1, in which the selected antennas are transmit antennas.

11. The method of claim 1, in which all steps operate at a media access control layer of the network.

12. The method of claim 1, in which the multiple sounding packets include data.

13. The method of claim 1, in which a size of a particular sounding packets is minimized by excluding data.

14. The method of claim 1, for further comprising:

selecting beams according to the channel matrix.

15. The method of claim 1, for further comprising:

indicating the selected subset of antennas by an index.

16. The method of claim 1, in which the station is a receive station.

17. The method of claim 1, in which the station is a transmit station.

18. The method of claim 1, where the sounding packets are transmitted using each subset of antennas of a transmit station.

19. The method of claim 1, in which each frame is replied after receiving each corresponding sounding packet.

20. The method of claim 1, in which each frame is replied after receiving all sounding packets.

21. The method of claim 3, in which the ASBFC field specifies a manner in which the subset of antennas is to be selected.

22. The method of claim 21, in which the selection is according to the channel matrix.

23. The method of claim 21, in which the selection is according to antenna indices.