Training Signals for Selecting Antennas and Beams in Mimo Wireless Lans

• US 20080247370A1
• Filed: 09/30/2005
• Published: 10/09/2008
• 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 8,514,815 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
• CPC Class Codes: H04B 7/0691 using subgroups of transmit antennas
• CPC Class Codes: H04B 7/0695 using beam selection
• CPC Class Codes: H04B 7/0851 using training sequences or error signal minimizing error signal H04B7/0854
• CPC Class Codes: H04B 7/0874 using subgroups of receive antennas
• CPC Class Codes: H04B 7/088 using beam selection

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, 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 consecutively transmitted sounding packets in a station, each sounding packet corresponding to a different subset of the set of antennas, and where the number of consecutive packets is predetermined;

estimating a channel matrix from the multiple consecutively transmitted sounding packets; and

selecting a subset of antennas according to the channel matrix.

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

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

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

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

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

selecting beams according to the channel matrix.

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

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

9. The method of claim 1, where the sounding packets are transmitted with a relatively short delay.

10. The method of claim 9, further comprising:

sending a link adaptation control frame (LAC) frame to initiate the antennas selection.

11. The method of claim 10, in which the LAC frame includes a LAC mask field, and the LAC mask field includes an antenna/beam selection indicator (ASI) field.

12. The method of claim 10, in which the LAC frame includes a modulation coding scheme (MCS) field, and if the ASI field is set to 1, then the MCS field is used for antenna/beam selection/transmitter beam forming control (ASBFC).

13. The method of claim 12 in which the ASBFC field includes a command selected from a group consisting of TX Antenna/Beam Selection Initiation (TXASI), TX Antenna/Beam Selection Initiation by RX (TXASI_RX), Antenna/Beam Selection Feedback (ASFB), RX Antenna/Beam Selection Initiation (RXASI), and TX Beam forming Initiation by RX

(TXBFI_RX).

14. The method of claim 1, further comprising:

sending a number of sounding packets that are to be sent to a station transmitting the sounding packets.

15. The method of claim 12, in which the station communicates the selected subset of antennas and the MCS that is to be used for further communication.

16. The method of claim 1, in which the station communicates to a station transmitting the sounding packets the channel matrix indicating complete channel state information.

17. The method of claim 16, in which the channel state information is used for performing transmit beam forming

18. The method of claim 1, in which the sounding packets are used with a transmit/receive calibration to select the subset of antennas.

19. The method of claim 1, in which the antenna selection is initiated by a receive station.

20. The method of claim 1, in which beam selection is used instead of antenna selection

21. The method of claim 1, in which joint RF-baseband processing is used instead of antenna selection.

22. The method of claim 1, in which the network is frequency-selective.

23. The methods of claim 1, in which the subset of antennas are selected alternately by a transmit station and a receive station.

24. A system 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:

a transmit station configured to transmit multiple consecutively transmitted sounding packets, each sounding packet corresponding to a different subset of the set of antennas, and where the number of consecutive packets is predetermined; and

a receive station configured to estimate a channel matrix from the multiple consecutively transmitted sounding packets, and to select a subset of antennas according to the channel matrix.

25. A system 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:

a receive station configured to transmit multiple consecutively transmitted sounding packets, each sounding packet corresponding to a different subset of the set of antennas, and where the number of consecutive packets is predetermined; and

a transmit station configured to estimate a channel matrix from the multiple consecutively transmitted sounding packets, and to select a subset of antennas according to the channel matrix.

26. A computer program product storing a computer program which when executed by a processor in a multiple-input, multiple-output wireless local area network including a plurality of stations, each station includes a set of antennas, causes the processor to perform steps of:

receiving multiple consecutively transmitted sounding packets in a station, each sounding packet corresponding to a different subset of the set of antennas, and where the number of consecutive packets is predetermined;

estimating a channel matrix from the multiple consecutively transmitted sounding packets; and

selecting a subset of antennas according to the channel matrix.

27. 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:

estimating a channel matrix from multiple consecutively transmitted sounding packets, each sounding packet corresponding to a different subset of the set of antennas; and

selecting a subset of antennas according to the channel matrix.