Abstract: In an 802.11az wireless system, a first station device transmits an NDP PPDU data unit in accordance with a range measurement packet exchange by constructing the NDP PPDU data unit to include an uplink (UL) length field element or a legacy signal length (LLEN) field element derived from a specified number of symbols (NHE-LTF) and number of repetitions (NLTF-REP) for the NDP PPDU data unit, and then sending the NDP PPDU data unit to a second STA device, where the values of the UL-length and LLEN field elements are computed as UL-Length=LLEN=10+y+6*?i=1NUM_USERS((NLTF-REP(i)+1)*NHE-LTF(i)), where y=0 for NTB I2R/R2I NDP and TB R2I NDP PPDUs, and where y=3 for TB-I2R NDP PPDUs.

Abstract: A first communication device prompts a plurality of second communication devices to transmit, during a contiguous time period reserved for a range measurement exchange, respective first null data packets (NDPs) at respective times. The first communication device receives first NDPs from at least some of the second communication devices during the contiguous time period, and transmits one or more second NDPs to the plurality of second communication devices. The first communication device uses reception of the first NDPs and transmission of the one or more second NDPs to determine respective ranges between the first communication device and respective second communication devices.

Abstract: A first client station receives from an access point an indication of whether angular information is to be included in feedback information in a range measurement session. The first client station transmits a null data packet (NDP) as part of an uplink multi-user (MU) PHY transmission that also includes simultaneous transmissions by one or more second client stations of one or more other respective NDPs to the access point as part of the range measurement session. The first client station receives a downlink physical layer (PHY) data unit from the access point that includes respective downlink feedback frames for the first client station and the one or more second client stations. When angular information is to be included in the feedback, a downlink feedback frame for the first client station includes angular information.

Abstract: A first communication device determines which one or more types of feedback information, from among a plurality of types of feedback information associated with a range measurement exchange session, a second communication device is to provide to the first communication device in a feedback packet transmitted as part of the range measurement exchange session. The first communication device transmits to the second communication device one or more indications of the determined one or more types of feedback information that the second communication device is to provide to the first communication device in the feedback packet. The first communication device performs the range measurement exchange, including receiving the feedback packet from the second communication device, wherein the feedback packet includes the determined one or more types of feedback information.

Abstract: An interrogation device, for locating a wireless device, includes a receiver and digital processing circuitry. The receiver includes one or more receiver stages having adjustable gains, and is configured to receive from the wireless device a signal that carries a packet including a direction-finding field, wherein, during reception of the direction-finding field, multiple different temporal sections of the received signal traverse different wireless channels due to switching among different antennas in the interrogation device or in the wireless device and thus have multiple different received-signal levels. The digital processing circuitry is configured, based on the multiple received temporal sections of the signal during reception of the direction-finding field, to (i) adapt the adjustable gains of the receiver stages and (ii) estimate a position of the wireless device.

Abstract: The present disclosure describes methods and apparatuses for secure fine timing measurement (FTM) with encoded long training fields (LTFs). In some aspects, a device transmits an announcement frame for an FTM exchange that includes an indication of encoding. Based on the indication of encoding, an LTF of a first null data packet (NDP) of the FTM exchange is encoded. The device transmits the first NDP having the encoded LTF to another device, and receives, from the other device, a second NDP having an encoded LTF. A round-trip time for the first and second NDPs with encoded LTFs is determined. Based on this round-trip time, a distance between the device and the other device can be determined. By encoding the LTFs of the NDPs of the FTM exchange, third parties can be prevented from spoofing an FTM frame to compromise the FTM exchange and related proximity-based security.

Abstract: A first communication device generates a frame that includes an indication of a transmit power corresponding to one or more null data packets (NDPs) separate from the frame to permit a second communication device to determine a pathloss between the first communication device and the second communication device based on a received power of the one or more NDPs at the second communication device. The first communication device transmits the frame as part of a ranging measurement exchange. As part of one or more ranging measurement exchanges, the first communication device transmits the one or more NDPs in accordance with the transmit power indicated in the frame.

Abstract: A communication device determines an identifier of a wireless network with which the communication device is not associated. While the communication device is not associated with the wireless network, the communication device participates in a ranging procedure with an access point (AP) of the wireless network. The ranging procedure is for estimating a distance between the communication device and the AP based on measuring times of flight of transmissions between the communication device and the AP. Participating in the ranging procedure includes: the communication device transmitting a packet to the AP as part of the ranging procedure. The packet includes a PHY preamble, and the PHY preamble includes a signal field. The signal field includes a wireless network identifier subfield set to the identifier of the wireless network.

Abstract: A first communication device generates a first ranging frame for transmission to a set of second communication devices, and transmitting the first ranging frame during an multi-user (MU) ranging measurement procedure for estimating respective distances between respective second communication devices, among the set of second communication devices, and the first communication device based on measuring times of flight of transmissions between the first communication device and the respective second communication devices. The first communication device then generates a second ranging frame to include timing information corresponding to transmission of the first ranging frame, the timing information indicative of a time of transmission of the first ranging frame by the first communication device.

Abstract: A first communication device determines which one or more types of feedback information, from among a plurality of types of feedback information associated with a range measurement exchange session, a second communication device is to provide to the first communication device in a feedback packet transmitted as part of the range measurement exchange session. The first communication device transmits to the second communication device one or more indications of the determined one or more types of feedback information that the second communication device is to provide to the first communication device in the feedback packet. The first communication device performs the range measurement exchange, including receiving the feedback packet from the second communication device, wherein the feedback packet includes the determined one or more types of feedback information.

Abstract: A first communication device generates and transmits a first trigger frame. One or more trigger type information fields of the first trigger frame are set to a first one or more respective values that indicates the first trigger frame is for: i) a multi-user (MU) ranging measurement procedure, and ii) causing multiple second communication devices to simultaneously transmit first null data packets (NDPs) as part of a first MU transmission associated with the MU ranging measurement procedure. The first communication device generates and transmits a second trigger frame. One or more trigger type information fields of the second trigger frame are set to a second one or more respective values that indicates the second trigger frame is for i) an MU ranging measurement procedure, and ii) causing the multiple second communication devices to simultaneously transmit feedback packets to the first communication device as part of a second MU transmission associated with the MU ranging measurement procedure.

Abstract: A first communication device prompts a plurality of second communication devices to transmit, during a contiguous time period reserved for a range measurement exchange, respective first null data packets (NDPs) at respective times. The first communication device receives first NDPs from at least some of the second communication devices during the contiguous time period, and transmits one or more second NDPs to the plurality of second communication devices. The first communication device uses reception of the first NDPs and transmission of the one or more second NDPs to determine respective ranges between the first communication device and respective second communication devices.

Abstract: At a receiver in a short-range wireless system having a plurality of channels and a plurality of receiving antennas, an angle-of-arrival of a signal is determined by receiving, at at least two antennas, the signal on one of the channels, determining a phase difference between the signal as received at those antennas, removing a local oscillator phase from the phase difference to provide an adjusted phase difference, and determining, from the adjusted phase difference, the angle-of-arrival. Removing the local oscillator phase includes estimating a local oscillator phase for each channel to be used for all antennas, or determining an angle using multi-channel combining, and for each channel, using that angle to determine a channel local oscillator phase, or, for a given channel, identifying, as the local oscillator phase, a phase that minimizes the sum, over all antennas, of squares of phase differences between the given channel and a neighboring channel.

Abstract: A first communication device determines which one or more types of feedback information, from among a plurality of types of feedback information associated with a range measurement exchange session, a second communication device is to provide to the first communication device in a feedback packet transmitted as part of the range measurement exchange session. The first communication device transmits to the second communication device one or more indications of the determined one or more types of feedback information that the second communication device is to provide to the first communication device in the feedback packet. The first communication device performs the range measurement exchange, including receiving the feedback packet from the second communication device, wherein the feedback packet includes the determined one or more types of feedback information.

Abstract: A first communication device prompts a plurality of second communication devices to transmit, during a contiguous time period reserved for a range measurement exchange, respective first null data packets (NDPs) at respective times. The first communication device receives first NDPs from at least some of the second communication devices during the contiguous time period, and transmits one or more second NDPs to the plurality of second communication devices. The first communication device uses reception of the first NDPs and transmission of the one or more second NDPs to determine respective ranges between the first communication device and respective second communication devices.

Abstract: In a range measurement signal exchange session between a first communication device and a second communication device, the first communication device generates an NDP, which includes: generating a plurality of training fields to be used by the second communication device to determine a time of arrival of the NDP. Each training field corresponds to a respective orthogonal frequency divisional multiplexing (OFDM) symbol. Generating the plurality of training fields includes: i) setting signal samples corresponding to guard intervals between the OFDM symbols to zero, and ii) for each OFDM symbol, setting a plurality of frequency domain values corresponding to OFDM sub carriers of the OFDM symbol to complex number values. The first communication device transmits the NDP as part of the range measurement signal exchange session.

Abstract: During a service period (SP) for a ranging measurement signal exchange between a first communication device and one or more second communication devices, the first communication device receives respective first null data packets (NDPs) from the one or more second communication devices, and transmits respective second NDPs to the one or more second communication devices. The first communication device transmits, during the SP, respective first ranging measurement feedback packets to the one or more second communication devices to allow each of the one or more second communication devices to determine a time-of-flight between the first communication device and the second communication device and/or receives, during the SP, respective second ranging measurement feedback packets from the one or more second communication devices to allow the first communication device to determine respective times-of-flight between the first communication device and the one or more second communication devices.

Abstract: Aspects of the disclosure provide an apparatus that includes a transceiver circuit and a processing circuit. The transceiver circuit is configured to transmit and receive wireless signals. The processing circuit is configured to generate a request frame using an extended control frame format to indicate an enhanced fine timing measurement (EFTM) based range measurement to a second apparatus, cause the transceiver circuit to transmit, when a transmission opportunity (TXOP) is granted to the apparatus, wireless signals carrying the request frame to start the EFTM based range measurement that exchanges null data packets with the second apparatus, and determine a round trip time based on departure and arrival timing information of the null data packets.

Abstract: Embodiments described herein provide a method for time delay estimation in a wireless communication system. A signal received, from a transmitter, is delayed due to hardware components in the receiver. A time domain representation of a computed complex channel impulse response (CIR) is generated. A first set of peaks of a time domain representation of the complex CIR is determined and a first peak, having a lowest time delay of the first set of peaks relative to the arrival time of the signal at the receiver, is identified. Following the interpolation of a region corresponding to the first peak, a second set of peaks is determined, and a more accurate estimation of the delay experienced by the signal through the receiver is determined.

Abstract: The present disclosure describes methods and apparatuses for fine timing measurement with frequency domain processing. In some aspects, a first device receives a frame that is transmitted by a second device via a wireless medium. A degree to which the frame is affected by multipath propagation in the wireless medium is determined based on frequency power and linear phase of the frame, which can be calculated using frequency domain processing. Based on the degree to which the frame is affected, a time of arrival calculation for the frame can be compensated for effects related to the multipath propagation. By so doing, the effects of multipath propagation can be addressed without time domain processing, which is typically complex and more expensive to implement.