A radio-frequency method for range finding includes modulating a reference signal having an intermediate frequency to a downlink signal having a carrier frequency using a clock signal. The downlink signal is transmitted to a tag using a transceiver. An uplink signal backscattered from the tag is received and demodulated using the clock signal. The uplink signal has a frequency that is a harmonic of the carrier frequency. A distance between the tag and the transceiver is calculated based on a phase of the demodulated uplink signal. A system for range finding includes a transceiver and a processor. The transceiver modulates a reference signal to a downlink signal and transmits the downlink signal. The transceiver receives and demodulates an uplink signal. The processor is configured to receive the demodulated uplink signal and calculate a distance between the tag and the transceiver using a phase of the demodulated uplink signal.

A transceiver is disclosed. The transceiver accesses a CFO (carrier frequency offset) estimate, and, for each of one or more working frequencies: transmits a transmitter RF signal at each working frequency, receives a receiver RF signal at each working frequency, and generates first I/Q measurement data based at least in part on the received receiver RF signal and the CFO estimate. In some embodiments, the transceiver receives I/Q measurement information for each working frequency. In some embodiments, the transceiver generates second I/Q measurement data based at least in part on the received I/Q measurement information. In some embodiments, the transceiver estimates a distance between the antenna and an antenna of another device based at least in part on the first and second I/Q measurement data.

In the present disclosure, a radar system is configured to interact with beacons that shift the phase of a received radar transmission to generate a phase shifted response signal. Phase shifters are designed to assign specific frequency responses to identify target locations. The radar module transmits at a modulated signal at first frequency, each beacon receives the radar transmission, phase shifts the signal and returns the phase shifted signal. Where two or more beacons are used, each will apply a different phase shift to the received radar transmission, wherein the frequency identifies the specific beacons. In a radar system, the modulated transmission signal is compared to the returned phase shifted signal to determine a frequency difference between the two signals.

In the present disclosure, a radar system is configured to interact with beacons that shift the phase of a received radar transmission to generate a phase shifted response signal. Phase shifters are designed to assign specific frequency responses to identify target locations. The radar module transmits at a modulated signal at first frequency, each beacon receives the radar transmission, phase shifts the signal and returns the phase shifted signal. Where two or more beacons are used, each will apply a different phase shift to the received radar transmission, wherein the frequency identifies the specific beacons. In a radar system, the modulated transmission signal is compared to the returned phase shifted signal to determine a frequency difference between the two signals.

Embodiments of the present disclosure describe mechanisms for radio frequency (RF) ranging between pairs of radio units based on radio signals exchanged between units. An exemplary radio system may include a first radio unit, configured to transmit a first radio signal, and a second radio unit configured to receive the first radio signal, adjust a reference clock signal of the second radio unit based on the first radio signal, and transmit a second radio signal generated based on the adjusted reference clock signal. Such a radio system may further include a processing unit for determining a distance between the first and second radio units based on a phase difference between the first radio signal as transmitted by the first radio unit and the second radio signal as received at the first radio unit. Disclosed mechanisms may enable accurate RF ranging using low-cost, low-power radio units.

Embodiments of the present disclosure describe mechanisms for radio frequency (RF) ranging between pairs of radio units based on radio signals exchanged between units. An exemplary radio system may include a first radio unit, configured to transmit a first radio signal, and a second radio unit configured to receive the first radio signal, adjust a reference clock signal of the second radio unit based on the first radio signal, and transmit a second radio signal generated based on the adjusted reference clock signal. Such a radio system may further include a processing unit for determining a distance between the first and second radio units based on a phase difference between the first radio signal as transmitted by the first radio unit and the second radio signal as received at the first radio unit. Disclosed mechanisms may enable accurate RF ranging using low-cost, low-power radio units.

Some embodiments enable secure time of flight (SToF) measurements for wireless communication packets that include secure ranging packets with zero padded random sequence waveforms, including at higher frequency bands (e.g., 60 GHz) and in non-line of sight (NLOS) scenarios. Some embodiments provide a flexible protocol to allow negotiation of one or more security parameters and/or SToF operation parameters. For example, some embodiments employ: phase tracking and signaling to support devices with phase noise constraints to mitigate phase noise at higher frequencies; determining a number of random sequences (RSs) used for SToF to support consistency checks and channel verification; additional rules supporting sub-phases of the SToF operation; and/or determining First Path (FP), Sub-Optimal, and/or Hybrid path AWV modes and the pre-conditioning usage of these modes.

Some embodiments enable secure time of flight (SToF) measurements for wireless communication packets that include secure ranging packets with zero padded random sequence waveforms, including at higher frequency bands (e.g., 60 GHz) and in non-line of sight (NLOS) scenarios. Some embodiments provide a flexible protocol to allow negotiation of one or more security parameters and/or SToF operation parameters. For example, some embodiments employ: phase tracking and signaling to support devices with phase noise constraints to mitigate phase noise at higher frequencies; determining a number of random sequences (RSs) used for SToF to support consistency checks and channel verification; additional rules supporting sub-phases of the SToF operation; and/or determining First Path (FP), Sub-Optimal, and/or Hybrid path AWV modes and the pre-conditioning usage of these modes.

According to an embodiment, a first device includes: a first transceiver configured to transmit two or more first carrier signals using an output of a first reference signal source and to receive two or more second carrier signals; and a calculation unit, and a second device includes: a second transceiver configured to transmit the two or more second carrier signals using an output of a second reference signal source that operates independently of the first reference signal source and to receive the two or more first carrier signals. A frequency group of the two or more first carrier signals and a frequency group of the two or more second carrier signals are identical or substantially identical to each other, and the calculation unit calculates the distance between the first device and the second device based on a phase detection result obtained by receiving the first and second carrier signals.

According to an embodiment, a first device includes: a first transceiver configured to transmit two or more first carrier signals using an output of a first reference signal source and to receive two or more second carrier signals; and a calculation unit, and a second device includes: a second transceiver configured to transmit the two or more second carrier signals using an output of a second reference signal source that operates independently of the first reference signal source and to receive the two or more first carrier signals. A frequency group of the two or more first carrier signals and a frequency group of the two or more second carrier signals are identical or substantially identical to each other, and the calculation unit calculates the distance between the first device and the second device based on a phase detection result obtained by receiving the first and second carrier signals.