Access point (AP), station (STA) and methods to negotiate fine timing measurement (FTM) parameters

1. An apparatus of an access point (AP), the apparatus comprising: memory; and processing circuitry, configured to:

encode, for transmission, a trigger frame (TF) that indicates resource units (RUs) that are available for contention based access by stations (STAs) for a fine timing measurement (FTM) protocol;

attempt to decode one or more initial fine timing measurement request (iFTMR) frames received in the indicated RUs;

encode, for transmission, a broadcast acknowledgement (ACK) frame that indicates whether at least one iFTMR frame was decoded;

for a decoded iFTMR frame:

allocate the RU corresponding to the decoded iFTMR frame to a corresponding STA for the FTM protocol; and

encode, for transmission in the corresponding RU, an initial fine timing measurement (iFTM) frame that includes an identifier of the corresponding STA.

2. The apparatus according to claim 1 , the processing circuitry further configured to:

encode, for transmission in the corresponding RU as part of the FTM protocol, a downlink null data packet (NDP) to enable a downlink timing measurement at the corresponding STA;

decode an uplink NDP received from the corresponding STA in the corresponding RU as part of the FTM protocol; and

determine an FTM for the corresponding STA based at least partly on an arrival time of the downlink NDP at the corresponding STA or an arrival time of the uplink NDP at the AP.

3. The apparatus according to claim 1 , wherein the identifier of the corresponding STA is a medium access control (MAC) address of the corresponding STA.

4. The apparatus according to claim 1 , wherein the broadcast ACK frame excludes identifiers of STAs from which decoded iFTMRs are received.

5. The apparatus according to claim 4 , the processing circuitry further configured to refrain from transmission of multi-user block ACK (M-BA) frames that include the identifiers of the STAs that transmitted the decoded iFTMRs.

6. The apparatus according to claim 1 , wherein:

the decoded iFTMR includes a first high efficiency wireless (HEWz) parameters element that includes one or more proposed FTM parameters,

the iFTM frame includes a second HEWz parameters element that indicates whether the AP accepts the proposed FTM parameters.

7. The apparatus according to claim 6 , the processing circuitry further configured to, if the corresponding STA is unassociated with the AP and if the AP accepts the proposed FTM parameters:

generate a pre-association identifier (pre-AID) for the corresponding STA; and

encode the iFTM to include the pre-AID in the second HEWz parameters element.

8. The apparatus according to claim 7 , the processing circuitry further configured to, if the corresponding STA is unassociated with the AP and if the AP rejects the proposed FTM parameters:

encode the iFTM to indicate a failure code in a status field of the second HEWz parameters element, wherein the failure code indicates that the AP rejects the proposed FTM parameters.

9. The apparatus according to claim 6 , wherein the proposed FTM parameters include an FTM response parameter that indicates one of:

immediate response, wherein FTM results are to be transmitted by the AP in a current availability window (AW) or in a next AW, and

delayed response, wherein FTM results are to be transmitted by the AP in another AW after the next AW.

10. The apparatus according to claim 1 , the processing circuitry further configured to attempt to decode the iFTMR frames in accordance with an orthogonal frequency division multiple access (OFDMA) technique or a multi-user (MU) technique.

11. The apparatus according to claim 1 , wherein the TF is a TF for Service Request (TSR).

12. The apparatus according to claim 1 , the processing circuitry further configured to store the decoded iFTMR from the corresponding STA in the memory.

13. The apparatus according to claim 1 , wherein the apparatus further includes a transceiver to:

transmit the TF and the broadcast ACK frame; and

receive the iFTMR frames.

14. The apparatus according to claim 1 , wherein the processing circuitry includes a baseband processor to:

encode the TF and the broadcast ACK frame; and

attempt to decode the iFTMR frames.

15. A non-transitory computer-readable storage medium that stores instructions for execution by one or more processors to perform operations for communication by a station (STA), the operations to configure the one or more processors to:

decode a trigger frame (TF) that indicates resource units (RUs) that are available for contention based access by STAs for a fine timing measurement (FTM) protocol with an access point (AP);

select one of the RUs;

encode, for transmission in the selected RU, an initial fine timing measurement request (iFTMR) frame;

decode a broadcast acknowledgement (ACK) frame that indicates whether at least one iFTMR frame was decoded by the AP;

if the broadcast ACK frame indicates that at least one iFTMR frame was decoded by the AP:

decode an initial fine timing measurement (iFTM) frame in the selected RU; and

determine, based on a comparison between a medium access control (MAC) address of the STA and a MAC address included in the iFTM frame, whether the selected RU is allocated to the STA for the FTM protocol.

16. The non-transitory computer-readable storage medium according to claim 15 , the operations to further configure the one or more processors to:

if it is determined that the selected RU is allocated to the STA for the FTM protocol:

encode, for transmission in the selected RU as part of the FTM protocol, an uplink null data packet (NDP) to enable an uplink timing measurement at the AP;

decode a downlink NDP received from the AP in the selected RU as part of the FTM protocol; and

determine an FTM based at least partly on an arrival time of the downlink NDP at the STA or an arrival time of the uplink NDP at the AP.

17. The non-transitory computer-readable storage medium according to claim 15 , the operations to further configure the one or more processors to:

encode the iFTMR frame for transmission in accordance with an orthogonal frequency division multiple access (OFDMA) technique or a multi-user (MU) technique.

18. A method of communication at an access point (AP), the method comprising:

encoding, for transmission, a trigger frame (TF) that indicates resource units (RUs) that are available for contention based access by stations (STAs) for a fine timing measurement (FTM) protocol;

attempting to decode one or more initial fine timing measurement request (iFTMR) frames received in the indicated RUs;

encoding, for transmission, a broadcast acknowledgement (ACK) frame that indicates whether at least one iFTMR frame was decoded;

for a decoded iFTMR frame:

allocating the RU corresponding to the decoded iFTMR frame to a corresponding STA for the FTM protocol; and

encoding, for transmission in the corresponding RU, an initial fine timing measurement (iFTM) frame that includes an identifier of the corresponding STA.

19. The method according to claim 18 , further comprising:

encoding, for transmission in the corresponding RU as part of the FTM protocol, a downlink null data packet (NDP) to enable a downlink timing measurement at the corresponding STA;

decoding an uplink NDP received from the corresponding STA in the corresponding RU as part of the FTM protocol; and

determining an FTM for the corresponding STA based at least partly on an arrival time of the downlink NDP at the corresponding STA or an arrival time of the uplink NDP at the AP.