Methods and systems for full duplex communications

1. A method comprising:

transmitting, by an access point (AP) having full duplex (FD) capabilities, a trigger frame to cause at least a first station (STA) that is an intended recipient of the trigger frame to initiate an uplink (UL) transmission including a UL reference frame to the AP immediately after a short interframe space (SIFS) from an end of the trigger frame, the trigger frame further causing at least one second STA that overhears the UL transmission established between the AP and at least the first STA to obtain a signal strength measurement during the UL transmission of the UL reference frame transmitted from at least the first STA and intended to be received by the AP; and

receiving, by the AP from the at least one second STA, a reporting frame containing information about the signal strength measurement.

2. The method of claim 1 , further comprising:

based on the information contained in the reporting frame, selecting a UL transmitting STA for a FD UL transmission during a DL transmission.

3. The method of claim 2 , further comprising:

storing, at the AP, potential interference information determined from the information contained in the reporting frame, the potential interference information indicating: for a given DL receiving STA, any acceptable UL transmitting STA for a FD UL transmission during a DL transmission to the given DL receiving STA;

wherein selecting the UL transmitting STA is performed using the stored potential interference information.

4. The method of claim 1 , further comprising:

based on the information contained in the reporting frame, selecting a DL receiving STA for a FD DL transmission during a UL transmission.

5. The method of claim 4 , further comprising:

storing, at the AP, potential interference information determined from the information contained in the reporting frame, the potential interference information indicating:

for a given UL transmitting STA, any acceptable DL receiving STA for a simultaneous FD DL transmission during a UL transmission by the given UL transmitting STA; and

wherein selecting the DL receiving STA is performed using the stored potential interference information.

6. The method of claim 1 , wherein the trigger frame causes a plurality of STAs to initiate transmission of respective UL reference frames to the AP, the respective UL reference frames being transmitted in sequence.

7. The method of claim 1 , wherein the trigger frame indicates at least one of: an identifier of at least the first STA, a transmission parameter for transmitting the UL response transmission, or a reporting parameter for the reporting frame.

8. The method of claim 7 , wherein the transmission parameter includes at least one of:

an indicator of a transmission power;

an indicator of a time-frequency pattern of reference symbols;

an indicator of a precoding to be used;

an indicator of a transmission duration; or

an indicator of a transmission resource to be used.

9. The method of claim 7 , wherein the reporting parameter includes at least one of:

an indicator of a tolerable interference threshold;

an indicator of a maximum number of tolerable interferers; or

an indicator of a time for transmitting the reporting frame.

10. The method of claim 1 , wherein the AP has capabilities for asynchronous FD communications.

11. The method of claim 1 , wherein the AP has capabilities for synchronous FD communications.

12. The method of claim 1 , further comprising:

when a UL reference frame from the first STA is not received, retransmitting, by the AP, the trigger frame to the first STA.

13. The method of claim 12 , further comprising:

when a UL reference frame from the first STA is not received after a preset time period or after a preset number of retransmissions, excluding the first STA from FD transmissions for at least a defined time period.

14. A method comprising:

in response to receipt of a trigger frame from an access point (AP), obtaining, by a second station (STA), a signal strength measurement during UL transmission of a first uplink (UL) reference frame transmitted from a first STA and intended to be received by the AP immediately after a short interframe space (SIFS) from an end of the trigger frame, wherein the first STA is an intended recipient of the trigger frame, and the second STA overhears the UL transmission established between the AP and the first STA; and

transmitting, to the AP, a reporting frame containing information about the signal strength measurement.

15. The method of claim 14 , wherein the information contained in the reporting frame includes at least one of:

a measured signal power; or

an identifier of a source of measured signal strength.

16. The method of claim 15 , wherein the information contained in the reporting frame includes only the measured signal power or the identifier for any signal strength measurements within a defined tolerable interference threshold.

17. The method of claim 14 , further comprising:

in response to receipt of the trigger frame from the AP, transmitting, by the second STA, a second UL reference frame to the AP.

18. The method of claim 17 , wherein the second UL reference frame is transmitted by the second STA in sequence with the first UL reference frame by the first STA.

19. An access point (AP) having full duplex (FD) capabilities, the AP comprising:

a communications interface for wireless communications with at least a first and a second station (STA); and

a processor configured to execute instructions to cause the AP to:

transmit a trigger frame, the trigger frame causing at least the first STA that is an intended recipient of the trigger frame to initiate transmission of an uplink (UL) reference frame to the AP immediately after a short interframe space (SIFS) from an end of the trigger frame, the trigger frame further causing at least the second STA that overhears the UL transmission established between the AP and at least the first STA to obtain a signal strength measurement during the UL transmission of the UL reference frame transmitted from at least the first STA and intended to be received by the AP; and

receive, from at least the second STA, a reporting frame containing information about the signal strength measurement.

20. The AP of claim 19 , wherein the processor is further configured to execute instructions to cause the AP to:

based on the information contained in the reporting frame, select a UL transmitting STA for a FD UL transmission during DL transmission.

21. The AP of claim 19 , wherein the processor is further configured to execute instructions to cause the AP to:

based on the information contained in the reporting frame, select a DL receiving STA for a FD DL transmission during a UL transmission.

22. The AP of claim 19 , wherein the trigger frame indicates at least one of: an identifier of at least the first STA, a transmission parameter for transmitting the UL reference frame, or a reporting parameter for the reporting frame.

23. A first station (STA) comprising:

a communications interface for wireless communications with an access point (AP); and

a processor configured to execute instructions to cause the first STA to:

in response to receipt of a trigger frame from the AP, obtain a signal strength measurement during transmission of a first uplink (UL) reference frame transmitted from a second STA and intended to be received by the AP immediately after a short interframe space (SIFS) from an end of the trigger frame, wherein the first STA overhears the transmission established between the AP and the first STA, and the second STA is an intended recipient of the trigger frame; and

transmit, to the AP, a reporting frame containing information about the signal strength measurement.

24. The first STA of claim 23 , wherein the processor is further configured to execute instructions to cause the first STA to:

in response to receipt of the trigger frame from the AP, transmit a second UL reference frame to the AP.