Feedback scheme for MU-MIMO

• US 8,547,955 B2
• Filed: 07/28/2010
• Issued: 10/01/2013
• Est. Priority Date: 07/28/2010
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Niu, Huaning, Li, Qinghua, Li, Honggang
• Primary Examiner(s): MARCELO, MELVIN C
• Application Number:
  US12/845,515
• Publication Number:
  US 20120026991A1
• Time in Patent Office: 1,161 Days
• Field of Search: 370/252, 370/345, 370/346
• US Class Current: 370/345
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/0643 Feedback on request
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0027 Scheduling of signalling, e.g. occurrence thereof
• CPC Class Codes: H04L 1/0029 Reduction of the amount of signalling, e.g. retention of useful signalling or differential signalling power control H04W52/04
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 5/0073 Allocation arrangements that take into account other cell interferences for intercell interference mitigation or co-ordination in orthogonal multiplex systems H04J11/005

Abstract

Embodiments of a system and method for managing feedback in a MU-MIMO system. An access point can announce one or more of mobile stations that are to receive downlink information in a first frame. The access point can also send a sounding package to the one or more mobile stations and receive feedback from the one or more mobile stations according to the feedback schedule. The feedback may be based on the reception of the sounding package.

Claims

1. A method to manage feedback in a multiple user multiple input multiple output (MU-MIMO) system, the method comprising:

sending a sounding package to one or more mobile stations including announcing one or more mobile stations, wherein sending the sounding package further comprises assigning a feedback schedule for the one or more mobile stations, said assigning a feedback schedule comprising determining a length of a feedback for a mobile station of the one or more mobile stations, the length of the feedback being determined based on a dimension of a feedback matrix received from the mobile station, and a number of downlink streams allocated to the mobile station;

receiving feedback from the one or more mobile stations based on the sounding package;

receiving modulation and coding scheme information from a mobile station of the one or more mobile stations; and

sending to the mobile station a downlink frame having a modulation and coding scheme based on the modulation and coding scheme information.

2. The method of claim 1, wherein said sending a sounding package further comprises assigning a feedback type for a mobile station of the one or more mobile stations, or assigning a dimension of a feedback matrix for the mobile station.

3. The method of claim 2, wherein the feedback type includes uncompressed channel state information feedback, un-compressed precoding matrix feedback, or compressed precoding matrix feedback.

4. The method of claim 3, wherein the feedback type is based on information from the mobile station regarding which of the uncompressed channel state information feedback, un-compressed precoding matrix feedback, or compressed precoding matrix feedback the mobile station supports.

5. The method of claim 1, wherein the modulation and coding scheme information is based on a reception quality of the downlink frame.

6. The method of claim 2, further comprising:

receiving a feedback matrix from a mobile station of the one or more mobile stations, the feedback matrix being determined based on a number of streams for the one or more mobile stations; and

sending a downlink frame to the mobile station using precoding adjustments based on the feedback matrix.

7. A method to generate feedback by a mobile station of one or more mobile stations in a MU-MIMO system, the method comprising:

receiving a sounding package from an access point including an announcement of one or more mobile stations;

sending feedback to the access point based on the sounding package;

sending modulation and coding scheme information to the access point;

sending a feedback matrix to the access point comprising summing a number of streams to be transmitted in a downlink frame by the access point and allocated to other mobile stations of the one or more mobile stations, and determining a feedback matrix for streams intended for the mobile station based on the number of streams and a reception quality of the sounding package from the access point; and

receiving a downlink frame from the access point having a modulation and coding scheme based on the modulation and coding scheme information.

8. The method of claim 7, wherein the sounding package further includes a feedback type or a dimension of a feedback matrix.

9. The method of claim 8, wherein said sending a feedback matrix to the access point is based on the feedback type and/or the dimension of the feedback matrix specified in the sounding package.

10. The method of claim 7, further comprising receiving an indication of the number of streams in the sounding package.

11. The method of claim 7, wherein the sounding package includes a feedback schedule for the one or more mobile stations of the MU-MIMO system.

12. The method of claim 7, further comprising calculating the modulation and coding scheme based on random and uniform interference from streams allocated to the other mobile stations of the one or more mobile stations, wherein the steams are transmitted with substantially equal power.

13. The method of claim 7, wherein the modulation and coding scheme information is piggybacked with an ACK/NACK.

14. The method of claim 7,

wherein the downlink frame from the access point is based on precoding adjustments based on the feedback matrix for the downlink frame.

15. An access point in a multiple user multiple input multiple output (MU-MIMO) system including one or more mobile stations, the access point comprising processing circuitry adapted to:

send a sounding package to one or more mobile stations including announcing one or more mobile stations, wherein to send the sounding package, the processing circuitry is further adapted to assign a feedback schedule for the one or more mobile stations, wherein the feedback schedule is based a determination of a length of a feedback for a mobile station of the one or more mobile stations, the length of the feedback being determined based on a dimension of a feedback matrix received from the mobile station, and a number of downlink streams allocated to the mobile station;

receive feedback from the one or more mobile stations based on the sounding package;

receive modulation and coding scheme information from a mobile station of the one or more mobile stations; and

send to the mobile station a downlink frame having a modulation and coding scheme based on the modulation and coding scheme information.

16. The access point of claim 15, wherein the sounding package further includes a feedback type for a mobile station of the one or more mobile stations and/or a dimension of a feedback matrix for the mobile station.

17. The access point of claim 16, wherein:

the feedback type includes uncompressed channel state information feedback, un-compressed precoding matrix feedback, or compressed precoding matrix feedback; and

the feedback type is based on information from the mobile station regarding which of the uncompressed channel state information feedback, un-compressed precoding matrix feedback, or compressed precoding matrix feedback the mobile station supports.

18. The access point of claim 15, wherein the modulation and coding scheme information sent by the mobile station is based on a reception quality of the downlink frame.

19. The access point of claim 15, wherein the processing circuitry is further adapted to:

receive a feedback matrix from a mobile station of the one or more mobile stations, the feedback matrix being determined based on a number of streams for the one or more mobile stations; and

send a downlink frame to the mobile station using precoding adjustments based on the feedback matrix.

20. A mobile station in a MU-MIMO system, the mobile station comprising processing circuitry adapted to:

receive a sounding package from an access point including an announcement of one or more mobile stations;

send feedback to the access point based on the sounding package;

send modulation and coding scheme information to the access point;

send a feedback matrix to the access point comprising summing a number of streams to be transmitted in a downlink frame by the access point and allocated to other mobile stations of the one or more mobile stations, and determine a feedback matrix for streams intended for the mobile station based on the number of streams and a reception quality of the sounding package from the access point; and

receive a downlink frame from the access point having a modulation and coding scheme based on the modulation and coding scheme information.

21. The mobile station of claim 20, wherein the sounding package further includes a feedback type and/or a dimension of a feedback matrix and a modulation and coding scheme for the mobile station.

22. The mobile station of claim 21, the mobile station further being adapted to send the feedback matrix to the access point based on the feedback type and/or the dimension of the feedback matrix specified in the sounding package.

23. The mobile station of claim 20, the mobile station further being adapted to receive an indication of the number of streams in the sounding package.

24. The mobile station of claim 20, the mobile station further being adapted to calculate the modulation and coding scheme based on random and uniform interference from streams allocated to the other mobile stations of the one or more mobile stations, wherein the steams are transmitted with substantially equal power.

25. The mobile station of claim 20, the mobile station further being adapted to piggyback the modulation and coding scheme information with an ACK/NACK.

26. The mobile station of claim 20,

wherein the downlink frame is based on precoding adjustments based on the feedback matrix for the downlink frame.

27. A computer-readable storage medium containing instructions that, if executed, enable an access point to manage feedback in a multiple user multiple input multiple output (MU-MIMO) system by:

sending a sounding package to one or more mobile stations including announcing one or more mobile stations, wherein sending the sounding package comprises assigning a feedback schedule for the one or more mobile stations, said assigning a feedback schedule comprising determining a length of a feedback for a mobile station of the one or more mobile stations, the length of the feedback being determined based on a dimension of a feedback matrix received from the mobile station, and a number of downlink streams allocated to the mobile station;

receiving feedback from the one or more mobile stations based on the sounding package;

receiving modulation and coding scheme information from a mobile station of the one or more mobile stations; and

sending to the mobile station a downlink frame having a modulation and coding scheme based on the modulation and coding scheme information.

28. The computer-readable storage medium of claim 27, wherein said sending a sounding package further comprises assigning a feedback type for a mobile station of the one or more mobile station, or assigning a dimension of a feedback matrix for the mobile station.

29. The computer-readable storage medium of claim 28, wherein:

the feedback type includes uncompressed channel state information feedback, un-compressed precoding matrix feedback, or compressed precoding matrix feedback; and

the feedback type is based on information from the mobile station regarding which of the uncompressed channel state information feedback, un-compressed precoding matrix feedback, or compressed precoding matrix feedback the mobile station supports.

30. The computer-readable storage medium of claim 27, wherein the modulation and coding scheme information is based on a reception quality of the downlink frame.

31. The computer-readable storage medium of claim 27, wherein the instructions further enable the access point to manage feedback in a MU-MIMO system by:

receiving a feedback matrix from a mobile station of the one or more mobile stations, the feedback matrix being determined based on a number of streams for the one or more mobile stations; and

sending a downlink frame to the mobile station using precoding adjustments based on the feedback matrix.