Multi-phase wireless sounding

1. An apparatus of an access point for multi-phase wireless sounding, the apparatus comprising:

a discriminator to:

select a first set of stations (STAs) from a plurality of STAs known to the AP; and

select a second set of STAs from the plurality of STAs based on a sounding report, the second set of STAs being smaller than the first set of STAs; and

a transmission controller to:

transmit a first sounding request to members of the first set of stations, the first sounding request including an indication of a report type, the report type being indicated is a partial report that instructs receiving STAs to report on less than all available sounding element measurements;

receive the sounding report in response to the first sounding request from a one or more of the first set of STAs; and

transmit a second sounding request to the second set of STAs, the second sounding request including a feedback type that instructs the receiving STAs to report compressed measurements, the compressed measurements being at least one of an average signal-to-noise ratio (SNR) or a delta SNR, each computed by combining a current measurement with a last measurement made to create the sounding report.

2. The apparatus of claim 1 , wherein to select the first set of STAs includes the discriminator to:

classify the plurality of STAs by at least one of STA capability, previously measured communication characteristic, expected allocation of sounding elements, expected transmit power metric, or expected beamforming format within a group of STAs; and

select STAs from the plurality of STAs that meet classification criteria for a current sounding.

3. The apparatus of claim 1 , wherein to select the second set of STAs based on the sounding report includes the discriminator to:

classify STAs represented in the sounding report with key performance indices, the key performance indices including AP quality of service, STA operation mode, STA long term link level, or STA-AP mutual interference level; and

select classified STAs when one or more key performance indices fail below respective thresholds.

4. The apparatus of claim 1 , wherein the first sounding request or the second sounding request is transmitted in a high efficiency (HE) null data packet (NDP) frame.

5. At least one non-transitory machine readable medium including instructions for multi-phase wireless sounding, the instructions, when executed by an access point (AP), cause the AP to:

select a first set of stations (STAs) from a plurality of STAs known to the AP;

transmit a first sounding request to members of the first set of stations, the first sounding request including an indication of a report type, the report type being indicated is a partial report that instructs receiving STAs to report on less than all available sounding element measurements;

receive a sounding report in response to the first sounding request from one or more of the first set of STAs;

select a second set of STAs from the plurality of STAs based on the sounding report, the second set of STAs being smaller than the first set of STAs; and

transmit a second sounding request to the second set of STA, the second sounding request including a feedback type that instructs the receiving STAs to report compressed measurements, the compressed measurements being at least one of an average signal-to-noise ratio (SNR) or a delta SNR, each computed by combining a current measurement with a last measurement made to create the sounding report.

6. The at least one machine readable medium of claim 5 , the report type indicates sounding element measurements.

7. The at least one machine readable medium of claim 6 , wherein the report type is an orthogonal frequency-division multiple access (OFDMA) report, and wherein the sounding element measurements are of sub-channel resource units.

8. The at least one machine readable medium of claim 5 , wherein to select the first set of STAs includes the AP to:

classify the plurality of STAs by at least one of STA capability, previously measured communication characteristic, expected allocation of sounding elements, expected transmit power metric, or expected beamforming format within a group of STAs; and

select STAs from the plurality of STAs that meet classification criteria for a current sounding.

9. The at least one machine readable medium of claim 5 , wherein to select the second set of STAs based on the sounding report includes the AP to:

classify STAs represented in the sounding report with key performance indices, the key performance indices including AP quality of service, STA operation mode, STA long term link level, or STA-AP mutual interference level; and

select classified STAs when one or more key performance indices fall below respective thresholds.

10. The at least one machine readable medium of claim 5 , wherein the first sounding request or the second sounding request is transmitted in a null data packet announcement (NDP-A) frame.

11. The at least one machine readable medium of claim 5 , wherein the first sounding request or the second sounding request is transmitted in a trigger frame for sounding (TFS).

12. The at least one machine readable medium of claim 5 , wherein the first sounding request or the second sounding request is transmitted in a high efficiency (HE) null data packet (NDP) frame.

13. A method for multi-phase wireless sounding, the method comprising:

selecting, by an access point (AP), a first set of stations (STAs) from a plurality of STAs known to the AP;

transmitting a first sounding request to members of the first set of stations, the first sounding request including an indication of a report type, the report type being indicated is a partial report that instructs receiving STAs to report on less than all available sounding element measurements;

receiving a sounding report in response to the first sounding request from one or more of the first set of STAs;

selecting a second set of STAs from the plurality of STAs based on the sounding report, the second set of STAs being smaller than the first set of STAs; and

transmitting a second sounding request to the second set of STAs, the second sounding request including a feedback type that instructs the receiving STAs to report compressed measurements, the compressed measurements being at least one of an average signal-to-noise ratio (SNR) or a delta SNR, each computed by combining a current measurement with a last measurement made to create the sounding report.

14. The method of claim 13 , wherein the report type indicates sounding element measurements.

15. The method of claim 14 , wherein the report type is a beamforming report requesting measurements on a set of spatial streams, and wherein the sounding element measurements are of spatial streams.

16. The method of claim 13 , wherein selecting the first set of STAs includes:

classifying the plurality of STAs by at least one of STA capability, previously measured communication characteristic, expected allocation of sounding elements, expected transmit power metric, or expected beamforming format within a group of STAs; and

selecting STAs from the plurality of STAs that meet classification criteria for a current sounding.

17. The method of claim 13 , wherein selecting the second set of STAs based on the sounding report includes:

classifying STAs represented in the sounding report with key performance indices, the key performance indices including AP quality of service, STA operation mode, STA long term link level, or STA-AP mutual interference level; and

selecting classified STAs when one or more key performance indices fall below respective thresholds.

18. The method of claim 13 , wherein the first sounding request or the second sounding request is transmitted in a trigger frame for sounding (TFS).

19. At least one non-transitory machine readable medium including instructions for multi-phase wireless sounding, the instructions, when executed by a station (STA), cause the STA to:

receive an initial request for an initial sounding report on sounding elements measurable at the STA, the initial request including an indication of a report type for the initial sounding report, the report type being indicated is a sparse report that instructs the STA to report on less than all available sounding element measurements;

receive a subsequent request for a subsequent sounding report, the subsequent request including a feedback type that instructs the STA to report compressed measurements, the compressed measurements being at least one of an average signal-to-noise ratio (SNR) or a delta SNR, each computed by combining a current measurement with a last measurement made to create the initial sounding report;

perform measurements in accordance to the subsequent sounding request; and

transmit a report of the sounding measurements in response to the subsequent request.

20. The at least one machine readable medium of claim 19 , wherein the STA is to receive a multi-user block acknowledgment (M-BA) in response to sending the subsequent sounding report.

21. The at least one machine readable medium of claim 20 , wherein the STA is to enter a low-power state in the STA following receipt of the M-BA.

22. The at least one machine readable medium of claim 19 , wherein the report type is a beamforming report requesting measurements on a set of spatial streams, and wherein the sounding element measurements are of spatial streams.

23. The at least one machine readable medium of claim 19 , wherein the report type is an orthogonal frequency-division multiple access (OFDMA) report, and wherein the sounding element measurements are of sub-channel resource units.