Beamforming smoothing and indication

1. An apparatus of a station comprising: a memory; and processing circuitry couple to the memory, wherein the processing circuitry is configured to:

decode a null data packet (NDP), the NDP being received on a channel from an access point;

determine channel matrix estimates across tones of the channel based on the NDP;

determine beamforming vectors or matrixes from the channel matrix estimate;

smooth the beamforming vectors or matrixes to generate smooth beamforming vectors or matrixes;

configure the station to transmit feedback in response to the NDP, the feedback comprising the smooth beamforming vectors or matrixes;

decode a downlink (DL) physical layer convergence procedure (PLCP) protocol data unit (PPDU)(DL PPDU) from the access point;

if the DL PPDU is beamformed based on the smooth beamforming vectors or matrixes, use a first channel smoothing method to smooth tones of the DL PPDU; and

if the DL PPDU is not beamformed based on the smooth beamforming vectors or matrixes, use a second channel smoothing method to smooth tones of the DL PPDU.

2. The apparatus of claim 1 , wherein the first channel smoothing method is linear minimum mean square error (LMMSE).

3. The apparatus of claim 1 , wherein the processing circuitry is further configured to:

determine whether the DL is smoothed based on a probabilistic determination.

4. The apparatus of claim 1 , wherein the processing circuitry is further configured to:

quantize the smooth beamforming vectors or matrixes to generate quantized beamforming vectors or matrixes; and

configure the station to transmit feedback in response to the NDP, the feedback comprising the quantized smooth beamforming vectors or matrixes.

5. The apparatus of claim 4 , wherein the processing circuitry is further configured to:

smooth the beamforming vectors or matrixes to generate smooth beamforming vectors or matrixes using one of the methods of the following group: global phase correction, interpolation, moving average, rotation within beamforming subspace, and feedback with global phase.

6. The apparatus of claim 5 , wherein the processing circuitry is further configured to:

determine the DL PPDU is beamformed based on the quantized smooth beamforming vectors or matrixes, if the station transmitted feedback to the access point comprising the quantized smooth beamforming vectors or matrixes.

7. The apparatus of claim 6 , wherein the processing circuitry is further configured to:

determine the DL PPDU is beamformed based on the quantized smooth beamforming vectors or matrixes, if the station transmitted feedback to the access point comprising the quantized smooth beamforming vectors or matrixes and the DL PPDU includes a field that indicates the DL PPDU is beamformed.

8. The apparatus of claim 4 , wherein the feedback further comprises a phase angle of each beamforming vector of the quantized smooth beamforming vectors or matrixes.

9. The apparatus of claim 4 , wherein the processing circuitry is further configured to:

determine the DL PPDU is beamformed based on the quantized smooth beamforming vectors or matrixes, if a field of the DL PPDU indicates that smooth beamforming vectors or matrixes were used to beamform the DL PPDU.

10. The apparatus of claim 1 , wherein the processing circuitry is further configured to:

smooth the beamforming vectors or matrixes to generate smooth beamforming vectors or matrixes using one of the methods of the following group: global phase correction, interpolation, moving average, rotation within beamforming subspace, and feedback with global phase.

11. The apparatus of claim 1 , wherein the processing circuitry is further configured to:

determine the DL PPDU is not beamformed based on the smooth beamforming vectors or matrixes, if the DL PPDU comprises a field that indicates that the DL PPDU is not beamformed or the DL comprises a field that indicates the smooth beamforming vectors or matrixes were not used to beamform the DL PPDU.

12. The apparatus of claim 1 , wherein the processing circuitry is further configured to:

determine the DL PPDU is beamformed based on the smooth beamforming vectors or matrixes, if one or more fields of the DL PPDU indicate that smooth beamforming vectors or matrixes were used to beamform the DL PPDU.

13. The apparatus of claim 1 , wherein the processing circuitry is further configured to:

smooth the channel matrix estimates across tones to generate smoothed channel matrix estimates across tones; and

determine beamforming vectors or matrixes from the smoothed channel matrix estimates.

14. The apparatus of claim 1 , wherein the station and the access point are each one or more from the following group:

an Institute of Electrical and Electronic Engineers (IEEE) 802.1 lax access point, an IEEE 802.11 station, an IEEE access point, a station acting as a group owner (GO), and an IEEE 802.11ax station.

15. The apparatus of claim 1 , further comprising transceiver circuitry coupled to the memory; and, one or more antennas coupled to the transceiver circuitry.

16. A non-transitory computer-readable storage medium that stores instructions for execution by one or more processors, the instructions to configure the one or more processors to cause an apparatus of a station to:

decode a null data packet (NDP), the NDP being received on a channel from an access point;

obtain channel matrix estimates across tones of the channel;

determine beamforming vectors or matrixes from the channel matrix estimate; and

smooth the beamforming vectors or matrixes to generate smooth beamforming vectors or matrixes;

configure the station to transmit feedback in response to the NDP, the feedback comprising the smooth beamforming vectors or matrixes;

decode a downlink (DL) physical layer convergence procedure (PLCP) protocol data unit (PPDU)(DL PPDU) from the access point;

if the DL PPDU is beamformed based on the smooth beamforming vectors or matrixes, use a first channel smoothing method to smooth tones of the DL PPDU; and

if the DL PPDU is not beamformed based on the smooth beamforming vectors or matrixes, use a second channel smoothing method to smooth tones of the DL PPDU.

17. The non-transitory computer-readable storage medium of claim 16 , wherein the instructions to further configure the one or more processors to cause the apparatus of the station to:

quantize the smooth beamforming vectors or matrixes to generate quantized beamforming vectors or matrixes; and

configure the station to transmit feedback in response to the NDP, the feedback comprising the quantized smooth beamforming vectors or matrixes.

18. A method performed by an apparatus of a station, the method comprising:

decoding a null data packet (NDP), the NDP being received on a channel from an access point;

obtaining channel matrix estimates across tones of the channel;

determining beamforming vectors or matrixes from the channel matrix estimate; and

smoothing the beamforming vectors or matrixes to generate smooth beamforming vectors or matrixes;

configuring the station to transmit feedback in response to the NDP, the feedback comprising the smooth beamforming vectors or matrixes;

decode a downlink (DL) physical layer convergence procedure (PLCP) protocol data unit (PPDU)(DL PPDU) from the access point;

if the DL PPDU is beamformed based on the smooth beamforming vectors or matrixes, use a first channel smoothing method to smooth tones of the DL PPDU; and

if the DL PPDU is not beamformed based on the smooth beamforming vectors or matrixes, use a second channel smoothing method to smooth tones of the DL PPDU.