Abstract: Techniques are provided for radio frequency (RF) sensing using a single wireless device. An example method for determining a distance to an object with radio frequency sensing includes transmitting a radio frequency signal with a transmit channel on a wireless device, receiving a leakage signal with a receive channel on the wireless device at a first time, such that the leakage signal is based on the radio frequency signal, receiving a reflected signal with the receive channel on the wireless device at a second time, such that the reflected signal is based on the radio frequency signal reflecting from the object, and determining the distance to the object based at least in part on a difference between the first time and the second time.

Abstract: This disclosure provides methods, devices and systems for radio frequency (RF) sensing in wireless communication systems. In some implementations, a transmitter device transmits sounding sequences configured for channel estimation over a wireless channel to a receiver device. The transmitter device also transmits or receives non-sounding frames associated with a channel report of the receiver device. The transmitter device transmits a frame soliciting the channel report from the receiver device. The transmitter device receives the channel report, which may include channel state information (CSI) of the wireless channel responsive to at least the sounding sequences. Some types of channel reports may take longer to generate than other types of channel reports. Transmitting or receiving the non-sounding frames during the time period may prevent other devices from accessing the wireless channel when the receiver device needs additional time to generate a certain type of channel report.

Abstract: In an aspect, a wireless device is configured to transmit a physical layer protocol data unit on one or more channels, wherein the physical layer protocol data unit includes a first portion and a second portion. The first portion includes a signal length field indicating a duration of a transmission of the physical layer protocol data unit. The second portion includes a plurality of Wi-Fi sensing fields. The wireless device is configured to receive a reflected signal and a leakage signal associated with the physical layer protocol data unit. The reflected signal includes the physical layer protocol data unit reflected off of a target object. The leakage signal is associated with the physical layer protocol data unit.

Abstract: This disclosure provides methods, devices, and systems for minimizing ranging errors resulting from clock drift and/or frequency offsets between wireless communication devices such as a responder device and an initiator device. In various implementations, the responder device receives a request for a ranging operation from the initiator device. The responder device determines whether its temperature exceeds a threshold. When the responder device's temperature exceeds the threshold, the responder device determines a time period after which the responder device's temperature is expected to decrease below the threshold. The responder device transmits a response frame indicating the responder device's temperature and the determined time period. In some instances, the determination that the responder device's temperature exceeds the threshold indicates that ranging errors resulting from clock drift and/or frequency offsets between the responder device and the initiator device are greater than an amount.

Abstract: Disclosed are systems and techniques for performing mapping using radio frequency (RF) sensing. For instance, a server can obtain a first set of RF sensing data and orientation data corresponding to a first wireless device from a plurality of wireless devices. The first set of RF sensing data can be associated with at least one received waveform that is a reflection of a transmitted waveform from a first reflector. Based on the first set of RF sensing data, orientation data, and location data corresponding to the first wireless device, an indoor map can be generated that includes a reference to the reflector.

Abstract: Techniques are provided for validating a mobile device in a passive digital key system. An example method of validating a mobile device includes determining a positioning measurement for the mobile device relative to a reference point, obtaining a measured distance with at least a first transceiver, obtaining a calibration distance based at least in part on the positioning measurement for the mobile device, computing a validation distance based at least in part on a difference between the measured distance and the calibration distance, and validating the mobile device based at least in part on a comparison of the validation distance and a threshold value.

Abstract: Techniques are provided for performing radio frequency (RF) sensing to determine the viewing status of a television user. This can be used to determine user behavior during the playback of content (e.g., whether a user is watching the content), which can be used as a data point for determining the user's level of interest in the content. Using the status of the television user, embodiments can provide additional or alternative functionality, such as powering down and/or powering up the television. Furthermore, RF sensing may be performed by existing television hardware, such a Wi-Fi transceiver, and may therefore provide RF sensing functionality to a television with little or no added cost.

Abstract: Disclosed are systems and techniques for detecting user presence, user motion, and for performing facial authentication. For instance, a wireless device can receive a waveform that is a reflection of a transmitted radio frequency (RF) waveform. Based on RF sensing data associated with the received waveform, the wireless device can determine a presence of a user. In response to determining the presence of the user, the wireless device can initiate facial authentication of the user.

Abstract: A communication device includes a processor configured to: transfer, via a transceiver, a wireless data signal within a communication frequency range; determine a capability of the communication device to measure a wireless radar signal received via the transceiver, the wireless radar signal having a frequency within the communication frequency range; transmit, via the transceiver to a network entity, a first indication of the capability of the communication device to measure the wireless radar signal, the first indication being indicative of a transmit power level of the wireless radar signal from a source of the wireless radar signal or a received power level of the wireless radar signal at the communication device; receive, via the transceiver, the wireless radar signal; determine a positioning measurement of the wireless radar signal; and transmit a second indication of the positioning measurement via the transceiver to the network entity.

Abstract: The present disclosure discloses a one-component type multi-functional fracturing fluid additive and a process for preparing the same. The process the following steps: mixing ethylene glycol, isopropanol, 1-butanol, 1-hexanol and 1-octanol, and heating to uniformly disperse the mixture to obtain an aqueous dispersant; adding a high molecular polymer thickener and an auxiliary agent to the aqueous dispersant, and stirring the mixture at a high speed to obtain a suspension, wherein the auxiliary agent is one or more selected from clay stabilizers, drainage aids, drag reducers, emulsion inhibitors, filtrate reducers, corrosion inhibitors and fungicides; and slowly stirring the suspension at a low speed, and cooling the suspension to room temperature to collect a sample of suspension. This auxiliary agent has good characteristics such as temperature resistance, shear resistance, salt resistance, and sand suspension.

Abstract: This disclosure provides systems, methods and apparatuses, including computer programs encoded on computer storage media, for ranging procedures performed using antenna switching. In one aspect, a device initiating a ranging procedure may transmit a ranging request, which may include antenna switching capabilities of the initiating device, a request for antenna switching by a responding device during the ranging procedure, or both. Ranging signaling may be communicated between the initiating device and the responding device using different transmit antennas, receive antennas, or both. In some implementations, ranging messages transmitted by the responding device may include transmit antenna indices used for transmission of different ranging messages, and receive antenna indices used for reception of different ranging response messages.

Abstract: Techniques are provided for utilizing wireless devices for contact tracing, and more specifically for detecting a barrier between devices to enhance contact tracing applications. An example method for detecting a barrier between a first device and a second device includes determining, by the first device, a first range measurement with respect to the second device using a first positioning technique determining, by the first device, a second range measurement with respect to the second device using a second positioning technique that is different from the first positioning technique, and detecting the barrier between the first device and the second device based on the first range measurement and the second range measurement.

Abstract: Ranging operations may be performed between an initiator device and a responder device using data frames as opposed to fine timing measurement (FTM) frames or Null Data Packet (NDP) frames. An initiator device may request the responder device to perform a ranging operation. The responder device may transmit a data frame to the initiator device and may receive an acknowledgement (ACK) frame from the responder device. The responder device may transmit a second data frame to the initiator device that includes ranging measurement information for the previous message exchange, including a time of departure of the data frame and a time of arrival of the ACK frame. Because data frames are encrypted, the ranging measurement information is provided in a secure manner. Moreover, by including the ranging measurement information in data frames, throughput for the ranging procedure is improved.

Abstract: Disclosed embodiments facilitate wireless channel calibration, including ranging and direction finding, between wirelessly networked devices. In some embodiments. a method on a first station (STA) may comprise: transmitting a first NDPA frame to one or more second stations (STAs), the first NDPA frame comprising a first bit indicating that one or more subsequent frames comprise ranging or angular information; and transmitting, after a Short Interval Frame Space (SIFS) time interval, a second frame. The second frame may be one of: a Null Data Packet az (NDP_az) frame with information about a time of transmission of the NDP_az frame, or a Null Data Packet (NDP) frame, or a Beam Refinement Protocol (BRP) frame. The first NDPA frame may be unicast, multicast, or broadcast.

Abstract: This disclosure provides systems, devices, apparatus and methods, including computer programs encoded on storage media, for initiating a secure FTM session between at least first and second STAs. A first STA initiates, with a second STA, a secure FTM session. The first STA receives a plurality of FTM packets from the second STA, each of the plurality of FTM packets including at least one preamble subject to a respective first CSD. The first STA transmits, to the second STA, an ACK for each of plurality of FTM packets. The first STA receives a measurement report including a ToD offset by the respective first CSD for each of the plurality of FTM packets, and a ToA at the second STA of each of a plurality of ACKs. The first STA determines a RTT between the first and second STAs based on the offset ToD and the ToA.

Abstract: Disclosed are systems, methods and devices for measuring a range between wireless devices using an exchange of messages between devices. For example, wireless transceiver devices may exchange messages transmitted in a wireless communications link to measure a time of flight. Based, at least in part, on the measured time of flight, a location of one of the wireless transceiver devices may be estimated.

Abstract: Disclosed are systems, methods and devices for obtaining round trip time measurements for use in location based services. In particular implementations, a fine timing measurement request message wirelessly transmitted by a first transceiver device to a second transceiver device may permit additional processing features in computing or applying a signal round trip time measurement. The fine timing measurement may include one or more files specifying a requested number of fine timing measurement messages requested for transmission from the first wireless transceiver device in response to fine timing measurement request message. Such a signal round trip time measurement may be used in positioning operations.

Abstract: In some implementations, an apparatus transmits information indicating a modulation and coding scheme (MCS) table for transmitting non-legacy acknowledgement (ACK) frames during a ranging operation to a responder device, receives a ranging frame including an indication of whether the responder device is capable of supporting the indicated MCS table, and transmits to the responder device an ACK frame using an MCS that is based on the capability of the responder device to support the MCS table. In other implementations, the apparatus receives from an initiator device information indicating an MCS table for transmitting non-legacy ACK frames during the ranging operation, transmits a ranging frame including an indication of whether the apparatus is capable of supporting the indicated MCS table, and receives from the initiator device an ACK frame transmitted using an MCS that is based on the capability of the apparatus to support the MCS table.

Abstract: This disclosure provides systems, methods, and apparatus, including computer programs encoded on computer-readable media, for a ranging protocol between two wireless local area network (WLAN) devices. In one aspect, the ranging protocol may be adjusted based on channel quality of a wireless medium between the WLAN devices. For example, a quantity of ranging frames and bandwidth for the ranging frames may be adjusted based on the channel quality. In some implementations, the channel quality may be determined using setup messages for the ranging protocol without a wireless association between the WLAN devices. The ranging protocol may be useful for range determination in an indoor environment where a WLAN is deployed. In some implementations, the ranging protocol may be used to determine a location of a WLAN device.

Abstract: This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for detecting motion using wireless local area network (WLAN) communications. A first WLAN device having multiple antennas (radios) may determine a metric based on differences in spatial signal processing characteristics between the multiple antennas. By comparing changes in the metric over a plurality of wireless signals over time, the first WLAN device may detect motion in the environment near the first WLAN device. The spatial signal processing characteristics may be based on received WLAN communications from a second WLAN device, based on beamforming feedback from the second WLAN device, or based on wireless signal reflections detected by the first WLAN device. Various techniques may be used to adjust or mitigate random phase differences between two antennas on some tones. Motion detection based on WLAN communications may trigger activities or notifications by the first WLAN device.