Abstract: Techniques described here introduce signature frequency modulation to unmodulated pulse signals as frequency chirps to enhance the security of multi-carrier phase-based ranging signals. The characteristics of the chirps may be mutually known by an initiator and a desired reflector of the ranging applications. The characteristics of the chirps may vary between the multi-carrier signals to thwart any attempt by an eavesdropper to predict the chirps. In one aspect, the characteristics of the chirps may be calculated for each timeslot of a ranging cycle by two authorized devices using a ciphering algorithm such as the Advanced Encryption Standard (AES) based on a shared security key. Each call of the AES may generate one or more pseudo-random numbers based on the shared security key and a time-varying initialization vector that increments every timeslot. Fields of the pseudo-random number may be extracted to determine the characteristics of the chirps associated with the timeslot.

Abstract: A system includes a broadcasting device and one or more receiving devices. The broadcast device is to broadcast an broadcast message to a set of receiving devices, wherein the broadcast message indicates that a broadcasting device is available for connection. The broadcasting device is also to receive, from a receiving device a response messages based on the broadcast message. The broadcasting device is further to determine a distance between the broadcasting device and the receiving device.

Abstract: A system and method for improving the accuracy of a secure phase-based ranging procedure and a Direction Finding procedure. The method includes receiving radio frequency signals from a second communication device. The method includes operating in a first mode including generating first location data based on the radio frequency signals and, transferring the first location data to a second processor in compliance with a Bluetooth Host Control Interface. The method includes comparing one or more conditions to one or more threshold values and responsive to the comparing transitioning from operating in the first mode to operating in a second mode. The method includes, while operating the second mode, generating second location data based on the radio frequency signals and, transferring the second location data to the second processor at a higher data transfer rate than the transferring of the first location data to the second processor.

Abstract: Techniques by a wireless to estimate the position of a remote device are disclosed. A main receiver of the wireless device may determine multiple first phase values of the RF signal received through a first antenna during multiple time intervals. An auxiliary receiver may determine multiple second phase values of the RF signal received through an array of auxiliary antennas during the multiple time intervals. Each of the second phase value may correspond to the RF signal received through one antenna of the array during one of the time interval. The wireless device may determine an oscillator offset between a local oscillator of the main transceiver and a local oscillator of the auxiliary receiver. The wireless device may estimate an angle of arrival (AoA) of the RF signal or a distance based on the multiple first phase values and the multiple second values by compensating for the oscillator phase offset.

Abstract: Techniques described here introduce signature frequency modulation to unmodulated pulse signals as frequency chirps to enhance the security of multi-carrier phase-based ranging signals. The characteristics of the chirps may be mutually known by an initiator and a desired reflector of the ranging applications. The characteristics of the chirps may vary between the multi-carrier signals to thwart any attempt by an eavesdropper to predict the chirps. In one aspect, the characteristics of the chirps may be calculated for each timeslot of a ranging cycle by two authorized devices using a ciphering algorithm such as the Advanced Encryption Standard (AES) based on a shared security key. Each call of the AES may generate one or more pseudo-random numbers based on the shared security key and a time-varying initialization vector that increments every timeslot. Fields of the pseudo-random number may be extracted to determine the characteristics of the chirps associated with the timeslot.

Abstract: Disclosed are techniques to compensate frequency systematic known error (FSKE) in reflector or initiator radios using a hybrid RF-digital approach in multi-carrier phase-based ranging. The hybrid RF-digital approach combines a coarse frequency compensation technique in the RF domain and a fine frequency compensation technique in the digital domain to remove the FSKE across all carrier frequencies from a device. The coarse frequency compensation performed in the RF domain may use a PLL to multiply the crystal frequency to arrive close to a target carrier frequency to compensate for a coarse portion of the known FSKE at the target frequency. The fine frequency compensation may use digital techniques to remove the remaining portion of the known FSKE not compensated by the RF. The hybrid approach reduces the number of fractional bits in the multiplier of the PLL when compared to an approach that uses only the RF-PLL to remove the FSKE.

Abstract: A method of wireless ranging between an initiator node and a responder node, involves performing a measurement procedure resulting in a two-way phase measurement between an initiator node and a responder node, the measurement procedure involving the initiator node transmitting an initiator carrier signal; the responder node performing a phase measurement of the initiator carrier signal relative to a responder node clock reference; the responder node transmitting a responder carrier signal; and the initiator node performing a phase measurement of the responder carrier signal relative to the initiator node clock reference, the method further involving calculating a distance between the initiator node and the responder node using as input the two-way phase measurements for the plurality of nominal frequencies; and a clock reference offset correction of the initiator node and of the responder node.

Abstract: A system and method for improving the accuracy of a secure phase-based ranging procedure and a Direction Finding procedure. The method includes receiving radio frequency signals from a second communication device. The method includes operating in a first mode including generating first location data based on the radio frequency signals and, transferring the first location data to a second processor in compliance with a Bluetooth Host Control Interface. The method includes comparing one or more conditions to one or more threshold values and responsive to the comparing transitioning from operating in the first mode to operating in a second mode. The method includes, while operating the second mode, generating second location data based on the radio frequency signals and, transferring the second location data to the second processor at a higher data transfer rate than the transferring of the first location data to the second processor.

Abstract: A multicarrier phase ranging system and method are provided. Generally, the method includes performing a handshake between first and a second transceiver to negotiate a list of channels and a start-time for a multicarrier phase ranging process. The process includes in a first cycle exchanging a Constant Tone (CT) between the first and second transceiver in a first epoch on a first channel, and processing the CT received in the first and second transceiver to measure a difference in phase between the CT received and a reference signal. The CT received is checked for interference using software or hardware in either or both of the first and second transceiver. If no interference is detected the first and second transceiver switch to another channel and exchange the CT at a next epoch. If interference is detected, at least one channel is skipped for at least a subsequent epoch.

Abstract: Disclosed are techniques to compensate frequency systematic known error (FSKE) in reflector or initiator radios using a hybrid RF-digital approach in multi-carrier phase-based ranging. The hybrid RF-digital approach combines a coarse frequency compensation technique in the RF domain and a fine frequency compensation technique in the digital domain to remove the FSKE across all carrier frequencies from a device. The coarse frequency compensation performed in the RF domain may use a PLL to multiply the crystal frequency to arrive close to a target carrier frequency to compensate for a coarse portion of the known FSKE at the target frequency. The fine frequency compensation may use digital techniques to remove the remaining portion of the known FSKE not compensated by the RF. The hybrid approach reduces the number of fractional bits in the multiplier of the PLL when compared to an approach that uses only the RF-PLL to remove the FSKE.

Abstract: A system and method for an efficient secure phase-based ranging using loopback calibration, including receiving, by a reflector during a current timeslot, an incoming constant tone (CT) signal having a phase shift; determining, by the reflector during the current timeslot or a previous timeslot, a phase shift correction value by using a receiver/transmitter (Rx/Tx) loopback path of the reflector; and/or generating, by the reflector, an outgoing CT signal having an updated phase shift by adjusting the phase shift of the incoming CT signal based on the phase shift correction value.

Abstract: A system and method for an efficient secure phase-based ranging using loopback calibration, including receiving, by a reflector during a current timeslot, an incoming constant tone (CT) signal having a phase shift; determining, by the reflector during the current timeslot or a previous timeslot, a phase shift correction value by using a receiver/transmitter (Rx/Tx) loopback path of the reflector; and/or generating, by the reflector, an outgoing CT signal having an updated phase shift by adjusting the phase shift of the incoming CT signal based on the phase shift correction value.

Abstract: Disclosed are techniques for time-multiplexing between sensing and adjacent signal transmission functionalities on the same hardware platform, such as a chipset supporting a main ranging device in passive entry passive start (PEPS) applications using secure multi-carrier phase-based ranging solutions to estimate the range between the main ranging device and a target device. The supporting chipset may be configured to operate as a sensor to receive continuous tone (CT) signals or round-trip time (RTT) packets exchanged between the main ranging device and the target device in a timeslot of a ranging cycle to improve the accuracy of the range estimates. In a different timeslot, the supporting device may operate as a transmitter to transmit CT signals or RTT packet on a channel adjacent to the channel used by the main ranging device to protect the CT signals or the RTT packets transmitted from the main ranging device against symbol level attacks.

Abstract: Disclosed are techniques for time-multiplexing between sensing and adjacent signal transmission functionalities on the same hardware platform, such as a chipset supporting a main ranging device in passive entry passive start (PEPS) applications using secure multi-carrier phase-based ranging solutions to estimate the range between the main ranging device and a target device. The supporting chipset may be configured to operate as a sensor to receive continuous tone (CT) signals or round-trip time (RTT) packets exchanged between the main ranging device and the target device in a timeslot of a ranging cycle to improve the accuracy of the range estimates. In a different timeslot, the supporting device may operate as a transmitter to transmit CT signals or RTT packet on a channel adjacent to the channel used by the main ranging device to protect the CT signals or the RTT packets transmitted from the main ranging device against symbol level attacks.

Abstract: Techniques by a wireless to estimate the position of a remote device are disclosed. A main receiver of the wireless device may determine multiple first phase values of the RF signal received through a first antenna during multiple time intervals. An auxiliary receiver may determine multiple second phase values of the RF signal received through an array of auxiliary antennas during the multiple time intervals. Each of the second phase value may correspond to the RF signal received through one antenna of the array during one of the time interval. The wireless device may determine an oscillator offset between a local oscillator of the main transceiver and a local oscillator of the auxiliary receiver. The wireless device may estimate an angle of arrival (AoA) of the RF signal or a distance based on the multiple first phase values and the multiple second values by compensating for the oscillator phase offset.

Abstract: A multicarrier phase ranging system and method are provided. Generally, the method includes performing a handshake between first and a second transceiver to negotiate a list of channels and a start-time for a multicarrier phase ranging process. The process includes in a first cycle exchanging a Constant Tone (CT) between the first and second transceiver in a first epoch on a first channel, and processing the CT received in the first and second transceiver to measure a difference in phase between the CT received and a reference signal. The CT received is checked for interference using software or hardware in either or both of the first and second transceiver. If no interference is detected the first and second transceiver switch to another channel and exchange the CT at a next epoch. If interference is detected, at least one channel is skipped for at least a subsequent epoch.

Abstract: A method is disclosed for group ranging in a wireless network. The wireless network comprises a plurality of nodes, including an initiator node and a plurality of responder nodes. The method includes performing, for each frequency in a plurality of frequencies, a measurement procedure involving a two-way phase measurement between the initiator node and each of the responder nodes. The measurement procedure includes the initiator node transmitting a carrier signal having the frequency, each responder node of the plurality of responder nodes receiving and performing a phase measurement of the carrier signal, each responder node of the plurality of responder nodes transmitting a carrier signal having the frequency, and the initiator node receiving and performing a phase measurement of the carrier signal. The method further includes calculating, between the initiator node and each responder node of the plurality of responder nodes, a distance, based on the performed two-way phase measurements.

Abstract: A method of wireless ranging between an initiator node and a responder node, involves performing a measurement procedure resulting in a two-way phase measurement between an initiator node and a responder node, the measurement procedure involving the initiator node transmitting an initiator carrier signal; the responder node performing a phase measurement of the initiator carrier signal relative to a responder node clock reference; the responder node transmitting a responder carrier signal; and the initiator node performing a phase measurement of the responder carrier signal relative to the initiator node clock reference, the method further involving calculating a distance between the initiator node and the responder node using as input the two-way phase measurements for the plurality of nominal frequencies; and a clock reference offset correction of the initiator node and of the responder node.

Abstract: A method is disclosed for group ranging in a wireless network. The wireless network comprises a plurality of nodes, including an initiator node and a plurality of responder nodes. The method includes performing, for each frequency in a plurality of frequencies, a measurement procedure involving a two-way phase measurement between the initiator node and each of the responder nodes. The measurement procedure includes the initiator node transmitting a carrier signal having the frequency, each responder node of the plurality of responder nodes receiving and performing a phase measurement of the carrier signal, each responder node of the plurality of responder nodes transmitting a carrier signal having the frequency, and the initiator node receiving and performing a phase measurement of the carrier signal. The method further includes calculating, between the initiator node and each responder node of the plurality of responder nodes, a distance, based on the performed two-way phase measurements.