Access point (ap), station (sta) and method of multi-user (mu) location measurment

A non-transitory computer-readable storage medium that stores instructions for execution by one or more processors to perform operations for communication by an access point (AP), the operations to configure the one or more processors to:

• contend for a transmission opportunity (TXOP) to obtain access to a channel;
• encode, for transmission, a trigger frame (TF) to initiate a multi-user (MU) location measurement during the TXOP;
• decode service requests for the MU location measurement from a plurality of stations (STAs), the service requests multiplexed in a first orthogonal frequency division multiple access (OFDMA) signal;
• encode, for transmission, an MU acknowledgement (ACK) frame that indicates reception of the service requests;
• decode, from the STAs, uplink sounding frames that include per-STA timing information for the service requests and the MU ACK frame, the uplink sounding frames multiplexed in a second OFDMA signal;
• and
• determine location measurements for the STAs based at least partly on the per-STA timing information included in the uplink sounding frames.

A method of sounding at a station (STA), the method comprising:

• decoding a trigger frame (TF) that indicates that a plurality of stations (STAs) are to transmit uplink sounding frames during a transmission opportunity (TXOP) obtained by an access point (AP);
• encoding, for transmission during the TXOP, an uplink sounding frame multiplexed in a first orthogonal frequency division multiple access (OFDMA) signal, the uplink sounding frame comprising training symbols for uplink channel state information (CSI) estimation;
• decoding a downlink sounding frame comprising training symbols for downlink CSI estimation, the downlink sounding frame multiplexed in a second OFDMA signal received during the TXOP;
• encoding, for transmission during the TXOP, an uplink location measurement report (LMR) that includes timing information for the transmission of the uplink sounding frame and the downlink sounding frames;
• and
• decoding a downlink LMR received during the TXOP, wherein the downlink LMR includes a location measurement for the STA based at least partly on the timing information included in the uplink LMR.

An apparatus of a station (STA), the apparatus comprising:

• memory;
• and processing circuitry, configured to:
• decode a trigger frame (TF) received during a transmission opportunity (TXOP) obtained by an access point (AP);
• encode, for transmission and in response to the TF, a service request for a location measurement of the STA as part of a multi-user (MU) location measurement by the AP, wherein the service request is multiplexed in a first orthogonal frequency division multiple access (OFDMA) signal;
• decode an MU acknowledgement (ACK) frame that indicates reception of the service request;
• encode, for transmission, an uplink sounding frame that includes timing information based at least partly on a transmission time of the service request and a reception time of the MU ACK frame, wherein the uplink sounding frame is multiplexed in a second OFDMA signal;
• and
• decode a downlink sounding frame that includes the location measurement for the STA, the location measurement based on the timing information.

An apparatus of an access point (AP), the apparatus comprising:

• memory;
• and processing circuitry, configured to:
• contend for a transmission opportunity (TXOP) to obtain access to a channel;
• encode, for transmission during the TXOP, a trigger frame (TF) to indicate that a plurality of stations (STAs) are to transmit uplink sounding frames;
• decode the uplink sounding frames multiplexed in a first orthogonal frequency division multiple access (OFDMA) signal received during the TXOP;
• and
• encode, for transmission during the TXOP, downlink sounding frames multiplexed in a second OFDMA signal.