Abstract: A circuit includes a first wireless radio frequency (RF) transceiver and a time-of-flight estimator included with or coupled to the first wireless RF transceiver. The time-of-flight estimator estimates a time-of-flight between the first wireless RF transceiver and a second wireless RF transceiver using: a first interval value that indicates an amount of time between when the second wireless RF transceiver received the message and when the second wireless RF transceiver transmitted the response; a first error value that indicates an offset between when the second wireless RF transceiver sampled the message and a target sampling point for the message; a second interval value that indicates an amount of time between when the TX chain sent the message and when the RX chain received the response; and a second error value that indicates an offset between when the RX chain sampled the response and a target sampling point for the response.

Abstract: An example apparatus includes target signal generator circuitry to generate a target signal having a first center frequency and a bandwidth. The example apparatus additionally includes companion signal generator circuitry to generate a companion signal having a second center frequency that is less than (a) the first center frequency adjusted by a first threshold and greater than (b) the first center frequency adjusted by a second threshold, the first threshold being a first multiple of the bandwidth, the second threshold being a second multiple of the bandwidth, the first multiple different than the second multiple. In some examples, the example apparatus includes adder circuitry to combine the target signal and the companion signal to form a composite signal. Additionally, the example apparatus includes transmitter circuitry to transmit the composite signal to a target device.

Abstract: Sequences to synchronize devices and related methods are disclosed herein including an access address generator to cryptographically generate a first bit sequence, an access address selector to read a first portion of the first bit sequence and read a second portion of the first bit sequence, the second portion different than the first portion, an access address analyzer to identify a first access address from a first section of the first portion based on a first criteria, the first criteria a function of a first autocorrelation function and identify a second access address from a second section of the second portion based on a second criteria, the second criteria a function of a second autocorrelation function.

Abstract: An example apparatus includes target signal generator circuitry to generate a target signal having a first center frequency and a bandwidth. The example apparatus additionally includes companion signal generator circuitry to generate a companion signal having a second center frequency that is less than (a) the first center frequency adjusted by a first threshold and greater than (b) the first center frequency adjusted by a second threshold, the first threshold being a first multiple of the bandwidth, the second threshold being a second multiple of the bandwidth, the first multiple different than the second multiple. In some examples, the example apparatus includes adder circuitry to combine the target signal and the companion signal to form a composite signal. Additionally, the example apparatus includes transmitter circuitry to transmit the composite signal to a target device.

Abstract: Sequences to synchronize devices and related methods are disclosed herein including an access address generator to cryptographically generate a first bit sequence, an access address selector to read a first portion of the first bit sequence and read a second portion of the first bit sequence, the second portion different than the first portion, an access address analyzer to identify a first access address from a first section of the first portion based on a first criteria, the first criteria a function of a first autocorrelation function and identify a second access address from a second section of the second portion based on a second criteria, the second criteria a function of a second autocorrelation function.

Abstract: Systems and methods of measuring distance between two wireless devices by combining phase shift and time-of-flight measurements. A first wireless devices sends a first packet to the second wireless device. After receiving the first packet, the second wireless device sending to the first wireless device a second packet. After sending the second packet, the second wireless device sends a first continuous wave signal to the first wireless device. After receiving the first continuous wave signal, the first wireless device sends to the second wireless device a second continuous wave signal. The first wireless device then calculates a time-of-flight measurement based on a time between the first wireless device sending the first packet and receiving the second packet, and calculates a second measurement based on a phase shift of the first continuous wave signal and the second continuous wave signal, and combines the two measurements.

Abstract: A method of relay-attack resistant communications in a wireless communications system that includes a master wireless device (Master) sending a synchronization signal to a slave wireless device (Slave). The synchronization signal includes timing information including a common time reference and a timeslot duration for interlocking Master communication timeslots for Master and Slave communication timeslots so that an alternating TX and RX role pattern is provided. The Master analyzes Slave packet data received from the Slave to identify overlaps of a transmission from the Master and the slave packet data, and in a case of detecting overlap, suspends communications from Master to Slave to prevent a relay-attack.

Abstract: Systems and methods of measuring distance between two wireless devices by combining phase shift and time-of-flight measurements. A first wireless devices sends a first packet to the second wireless device. After receiving the first packet, the second wireless device sending to the first wireless device a second packet. After sending the second packet, the second wireless device sends a first continuous wave signal to the first wireless device. After receiving the first continuous wave signal, the first wireless device sends to the second wireless device a second continuous wave signal. The first wireless device then calculates a time-of-flight measurement based on a time between the first wireless device sending the first packet and receiving the second packet, and calculates a second measurement based on a phase shift of the first continuous wave signal and the second continuous wave signal, and combines the two measurements.

Abstract: A circuit includes a first wireless radio frequency (RF) transceiver and a time-of-flight estimator included with or coupled to the first wireless RF transceiver. The time-of-flight estimator estimates a time-of-flight between the first wireless RF transceiver and a second wireless RF transceiver using: a first interval value that indicates an amount of time between when the second wireless RF transceiver received the message and when the second wireless RF transceiver transmitted the response; a first error value that indicates an offset between when the second wireless RF transceiver sampled the message and a target sampling point for the message; a second interval value that indicates an amount of time between when the TX chain sent the message and when the RX chain received the response; and a second error value that indicates an offset between when the RX chain sampled the response and a target sampling point for the response.

Abstract: A method of relay-attack resistant communications in a wireless communications system that includes a master wireless device (Master) sending a synchronization signal to a slave wireless device (Slave). The synchronization signal includes timing information including a common time reference and a timeslot duration for interlocking Master communication timeslots for Master and Slave communication timeslots so that an alternating TX and RX role pattern is provided. The Master analyzes Slave packet data received from the Slave to identify overlaps of a transmission from the Master and the slave packet data, and in a case of detecting overlap, suspends communications from Master to Slave to prevent a relay-attack.

Abstract: A technique of separating a sequence of modulation shift keying (MSK) symbols into a first portion and a second portion and separately comparing the first portion of the sequence of MSK symbols and the second portion of the sequence of MSK symbols against a first portion of a reference sequence of MSK symbols and a second portion of the reference sequence of MSK symbols allows a low complexity detection of a start field delimiter in a wireless communication packet.

Abstract: A circuit includes a first wireless radio frequency (RF) transceiver and a time-of-flight estimator included with or coupled to the first wireless RF transceiver. The time-of-flight estimator estimates a time-of-flight between the first wireless RF transceiver and a second wireless RF transceiver using: a first interval value that indicates an amount of time between when the second wireless RF transceiver received the message and when the second wireless RF transceiver transmitted the response; a first error value that indicates an offset between when the second wireless RF transceiver sampled the message and a target sampling point for the message; a second interval value that indicates an amount of time between when the TX chain sent the message and when the RX chain received the response; and a second error value that indicates an offset between when the RX chain sampled the response and a target sampling point for the response.

Abstract: An example apparatus includes target signal generator circuitry to generate a target signal having a first center frequency and a bandwidth. The example apparatus additionally includes companion signal generator circuitry to generate a companion signal having a second center frequency that is less than (a) the first center frequency adjusted by a first threshold and greater than (b) the first center frequency adjusted by a second threshold, the first threshold being a first multiple of the bandwidth, the second threshold being a second multiple of the bandwidth, the first multiple different than the second multiple. In some examples, the example apparatus includes adder circuitry to combine the target signal and the companion signal to form a composite signal. Additionally, the example apparatus includes transmitter circuitry to transmit the composite signal to a target device.

Abstract: Techniques related to measuring a time-of-flight (ToF), comprising switching a first measuring station to a main operating mode, transmitting, by the first measuring station, a first ToF packet to a remote device, switching the first measuring station to a receive mode to receive a first ToF response packet from the remote device, receiving, by the first measuring station, the first ToF response packet, determining, a time interval between transmitting of the first ToF packet and receiving the first ToF response packet, receiving a plurality of time intervals from one or more other measuring stations, determining a ToF measurement based on the first time interval and the plurality of time intervals, switching the first measuring station to a secondary operating mode, and transmitting to a second measuring station, an indication to switch to the main operating mode.

Abstract: Sequences to synchronize devices and related methods are disclosed herein including an access address generator to cryptographically generate a first bit sequence, an access address selector to read a first portion of the first bit sequence and read a second portion of the first bit sequence, the second portion different than the first portion, an access address analyzer to identify a first access address from a first section of the first portion based on a first criteria, the first criteria a function of a first autocorrelation function and identify a second access address from a second section of the second portion based on a second criteria, the second criteria a function of a second autocorrelation function.

Abstract: A circuit includes a first wireless radio frequency (RF) transceiver and a time-of-flight estimator included with or coupled to the first wireless RF transceiver. The time-of-flight estimator estimates a time-of-flight between the first wireless RF transceiver and a second wireless RF transceiver using: a first interval value that indicates an amount of time between when the second wireless RF transceiver received the message and when the second wireless RF transceiver transmitted the response; a first error value that indicates an offset between when the second wireless RF transceiver sampled the message and a target sampling point for the message; a second interval value that indicates an amount of time between when the TX chain sent the message and when the RX chain received the response; and a second error value that indicates an offset between when the RX chain sampled the response and a target sampling point for the response.

Abstract: Systems and methods of measuring distance between two wireless devices by combining phase shift and time-of-flight measurements. A first wireless devices sends a first packet to the second wireless device. After receiving the first packet, the second wireless device sending to the first wireless device a second packet. After sending the second packet, the second wireless device sends a first continuous wave signal to the first wireless device. After receiving the first continuous wave signal, the first wireless device sends to the second wireless device a second continuous wave signal. The first wireless device then calculates a time-of-flight measurement based on a time between the first wireless device sending the first packet and receiving the second packet, and calculates a second measurement based on a phase shift of the first continuous wave signal and the second continuous wave signal, and combines the two measurements.

Abstract: A method is provided. In some examples, the method includes generating, by processing circuitry, a spread of chips representing an input bit. In addition, the method includes converting, by the processing circuitry, the spread of chips to a plurality of symbols comprising a pair of symbols. The method also includes mapping, by the processing circuitry, the pair of symbols to a single carrier signal and generating, by the processing circuitry, a radio-frequency (RF) signal based on the single carrier signal. The method further includes transmitting, by the processing circuitry via an antenna, the RF signal.

Abstract: Techniques related to measuring a time-of-flight (ToF), comprising switching a first measuring station to a main operating mode, transmitting, by the first measuring station, a first ToF packet to a remote device, switching the first measuring station to a receive mode to receive a first ToF response packet from the remote device, receiving, by the first measuring station, the first ToF response packet, determining, a time interval between transmitting of the first ToF packet and receiving the first ToF response packet, receiving a plurality of time intervals from one or more other measuring stations, determining a ToF measurement based on the first time interval and the plurality of time intervals, switching the first measuring station to a secondary operating mode, and transmitting to a second measuring station, an indication to switch to the main operating mode.

Abstract: Systems and methods of measuring distance between two wireless devices by combining phase shift and time-of-flight measurements. A first wireless devices sends a first packet to the second wireless device. After receiving the first packet, the second wireless device sending to the first wireless device a second packet. After sending the second packet, the second wireless device sends a first continuous wave signal to the first wireless device. After receiving the first continuous wave signal, the first wireless device sends to the second wireless device a second continuous wave signal. The first wireless device then calculates a time-of-flight measurement based on a time between the first wireless device sending the first packet and receiving the second packet, and calculates a second measurement based on a phase shift of the first continuous wave signal and the second continuous wave signal, and combines the two measurements.