Systems and methods for determining a channel variation metric

1. A method for determining a channel variation metric by an electronic device, comprising:

receiving a first packet;

receiving a second packet;

determining a channel variation metric that approximates a mean square error value based on a first channel estimate corresponding to a first packet and a second channel estimate corresponding to a second packet; and

performing an operation based on the channel variation metric, the operation comprising switching between a single-user multiple input and multiple output (SU-MIMO) mode and a multi-user multiple input and multiple output (MU-MIMO) mode.

2. The method of claim 1 , wherein the channel variation metric is insensitive to gain variation and phase variation.

3. The method of claim 1 , wherein performing an operation further comprises switching to an open loop mode.

4. The method of claim 1 , wherein performing an operation comprises requesting feedback.

5. The method of claim 4 , wherein requesting feedback occurs when the channel variation metric is less than a threshold.

6. The method of claim 1 , wherein performing an operation comprises sending a multi-user multiple input and multiple output (MU-MIMO) packet without requesting feedback.

7. The method of claim 1 , wherein performing an operation comprises determining a maximum time between feedback requests for at least one of the multi-user multiple input and multiple output (MU-MIMO) mode and the single-user multiple input and multiple output (SU-MIMO) mode.

8. The method of claim 1 , wherein determining the channel variation metric comprises:

determining absolute values of channel measurements corresponding to the first packet and to the second packet;

determining a mean amplitude per antenna;

determining normalized values based on the mean amplitude per antenna; and

subtracting the normalized values.

9. The method of claim 1 , wherein determining the channel variation metric is based on a subset of tones.

10. A communication device for determining a channel variation metric, comprising:

receiver circuitry that receives a first packet and receives a second packet;

channel variation metric computation circuitry coupled to the receiver circuitry, wherein the channel variation metric computation circuitry determines a channel variation metric that approximates a mean square error value based on a first channel estimate corresponding to a first packet and a second channel estimate corresponding to a second packet; and

operations circuitry coupled to the channel variation metric computation circuitry, wherein the operations circuitry performs an operation based on the channel variation metric, the operation comprising switching between a single-user multiple input and multiple output (SU-MIMO) mode and a multi-user multiple input and multiple output (MU-MIMO) mode.

11. The communication device of claim 10 , wherein the channel variation metric is insensitive to gain variation and phase variation.

12. The communication device of claim 10 , wherein performing an operation further comprises switching to an open loop mode.

13. The communication device of claim 10 , wherein performing an operation comprises requesting feedback.

14. The communication device of claim 13 , wherein requesting feedback occurs when the channel variation metric is less than a threshold.

15. The communication device of claim 10 , wherein performing an operation comprises sending a multi-user multiple input and multiple output (MU-MIMO) packet without requesting feedback.

16. The communication device of claim 10 , wherein performing an operation comprises determining a maximum time between feedback requests for at least one of the multi-user multiple input and multiple output (MU-MIMO) mode and the single-user multiple input and multiple output (SU-MIMO) mode.

17. The communication device of claim 10 , wherein determining the channel variation metric comprises:

determining absolute values of channel measurements corresponding to the first packet and to the second packet;

determining a mean amplitude per antenna;

determining normalized values based on the mean amplitude per antenna; and

subtracting the normalized values.

18. The communication device of claim 10 , wherein determining the channel variation metric is based on a subset of tones.

19. A computer-program product for determining a channel variation metric, comprising a non-transitory tangible computer-readable medium having instructions thereon, the instructions comprising:

code for causing a communication device to receive a first packet;

code for causing the communication device to receive a second packet;

code for causing the communication device to determine a channel variation metric that approximates a mean square error value based on a first channel estimate corresponding to a first packet and a second channel estimate corresponding to a second packet; and

code for causing the communication device to perform an operation based on the channel variation metric, the operation comprising switching between a single-user multiple input and multiple output (SU-MIMO) mode and a multi-user multiple input and multiple output (MU-MIMO) mode.

20. The computer-program product of claim 19 , wherein the channel variation metric is insensitive to gain variation and phase variation.

21. The computer-program product of claim 19 , wherein code for causing the communication device to perform an operation further comprises code for causing the communication device to switch to an open loop mode.

22. The computer-program product of claim 19 , wherein code for causing the communication device to perform an operation comprises code for causing the communication device to request feedback.

23. The computer-program product of claim 22 , wherein requesting feedback occurs when the channel variation metric is less than a threshold.

24. The computer-program product of claim 19 , wherein performing an operation comprises sending a multi-user multiple input and multiple output (MU-MIMO) packet without requesting feedback.

25. The computer-program product of claim 19 , wherein code for causing the communication device to perform comprises code for causing the communication device to determine a maximum time between feedback requests for at least one of the multi-user multiple input and multiple output (MU-MIMO) mode and the single-user multiple input and multiple output (SU-MIMO) mode.

26. The computer-program product of claim 19 , wherein code for causing the communication device to determine the channel variation metric comprises:

code for causing the communication device to determine absolute values of channel measurements corresponding to the first packet and to the second packet;

code for causing the communication device to determine a mean amplitude per antenna;

code for causing the communication device to determine normalized values based on the mean amplitude per antenna; and

code for causing the communication device to subtract the normalized values.

27. The computer-program product of claim 19 , wherein code for causing the communication device to determine the channel variation metric is based on a subset of tones.

28. An apparatus for determining a channel variation metric, comprising:

means for receiving a first packet;

means for receiving a second packet;

means for determining a channel variation metric that approximates a mean square error value based on a first channel estimate corresponding to a first packet and a second channel estimate corresponding to a second packet; and

means for performing an operation based on the channel variation metric, the operation comprising switching between a single-user multiple input and multiple output (SU-MIMO) mode and a multi-user multiple input and multiple output (MU-MIMO) mode.

29. The apparatus of claim 28 , wherein the channel variation metric is insensitive to gain variation and phase variation.

30. The apparatus of claim 28 , wherein the means for performing an operation further comprises means for switching to an open loop mode.

31. The apparatus of claim 28 , wherein means for performing an operation comprises means for requesting feedback.

32. The apparatus of claim 31 , wherein requesting feedback occurs when the channel variation metric is less than a threshold.

33. The apparatus of claim 28 , wherein means for performing an operation comprises means for sending a multi-user multiple input and multiple output (MU-MIMO) packet without requesting feedback.

34. The apparatus of claim 28 , wherein the means for performing an operation comprises means for determining a maximum time between feedback requests for at least one of the multi-user multiple input and multiple output (MU-MIMO) mode and the single-user multiple input and multiple output (SU-MIMO) mode.

35. The apparatus of claim 28 , wherein means for determining the channel variation metric comprises:

means for determining absolute values of channel measurements corresponding to the first packet and to the second packet;

means for determining a mean amplitude per antenna;

means for determining normalized values based on the mean amplitude per antenna; and

means for subtracting the normalized values.

36. The apparatus of claim 28 , wherein means for determining the channel variation metric is based on a subset of tones.