A transceiver circuit is disclosed. The transceiver circuit includes an antenna, a receiver RF chain configured to receive a receiver RF signal from the antenna, a transmitter RF chain configured to transmit a transmitter RF signal to the antenna, and a controller configured to access a CFO (carrier frequency offset) estimate, and to, for each of one or more working frequencies: cause the receiver RF chain to receive a receiver RF signal from the antenna at each working frequency, generate I/Q measurement data based at least in part on the received receiver RF signal and the CFO estimate, store the I/Q measurement data, and cause the transmitter RF chain to transmit a transmitter RF signal to the antenna at each working frequency, where the controller is further configured to cause the transmitter RF chain to transmit the I/Q measurement data for each working frequency to the antenna.

Markers and related systems and methods are provided for localizing lesions within a patient's body, e.g., within a breast. The marker includes one or more photosensitive diodes for transforming light pulses striking the marker into electrical energy, one or more antennas, and a switch coupled to the photodiodes and antennas such that the light pulses cause the switch to open and close and modulate radar signals reflected by the marker back to a source of the signals. The antenna(s) may include one or more wire elements extending from a housing, one or more antenna elements printed on a substrate, or one or more chip antennas. Optionally, the marker may include a processor coupled to the photodiodes for identifying signals in the light pulses or one or more coatings or filters to allow selective activation of the marker.

A transmitter at a first location transmits the message at a symbol rate of the reference clock using a first carrier, whose phase is locked to a phase of the reference clock and whose frequency is a first integer times a frequency of the reference clock. It also transmits the message at the symbol rate of the reference clock using a second carrier, whose phase is locked to the phase of the reference clock and whose frequency is a second integer times the frequency of the reference clock. The second integer is unequal to the first integer. A receiver at a second location receives the message at the first carrier and at the second carrier, and accurately determines a time of a first phase difference between the first carrier and the second carrier. It determines a time of receiving the message from the time of the first phase difference.

A system for estimating a distance between vehicles may include an oscillator, a transmitter, a receiver, a summing circuit, a signal analyzer, a tunable phase shifter, a distance estimator, and/or a vehicle identifier. The oscillator may generate a generated oscillating signal, transmitted by the transmitter. The receiver may receive a processed signal derived by a system of a second vehicle. The summing circuit may add the generated oscillating signal to the received signal to produce the updated oscillating signal. The signal analyzer may detect a spike in amplitude associated with the updated oscillating signal. The tunable phase shifter may shift a phase of the generated oscillating signal by an incremental phase shift amount until a spike in amplitude is detected. The distance estimator may estimate the distance between the first vehicle and the second vehicle based on a total phase shift amount and the predetermined wavelength.

An arrangement (100, 200, 300) for monitoring of at least one distance between antenna units, the arrangement comprising at least two antenna units (104, 106, 116, 118, 136, 138), each antenna unit being associated with a radio unit (108, 110), the arrangement additionally comprising at least one radio unit being associated with at least one of the at least two antenna units, and at least one processor. The two antenna units are configured to placed at at least first and second locations, the arrangement being configured to execute at least two measurement cycles wherein during each measurement cycle the arrangement is configured to transmit at least one signal via antenna units one at a time and determine phase information for said signals being received by remaining antenna units. Distance variables determined based on the phase information are used to determine a change in distance between antenna units between measurement cycles.

A system for synchronizing communications in a radio ranging process involves transmitting calibration signals according to a predetermined schedule of nominal transmission times. Timing offsets are determined. A start time is determined for a transmission of a ranging signal. The start time is earlier than a nominal start time of the ranging signal by at least the largest timing offset. Another system for synchronization involves a radio device transmitting a calibration signal to a second radio device and receiving a calibration response signal from the second radio device. A time-of-flight value is determined in dependence on a time of departure of the calibration signal and a time of arrival of the calibration response signal. A ranging signal is transmitted at a time determined in dependence on the determined time-of-flight value. A ranging response signal is received and processed to determine a range value.

A method for use in a wireless transmit/receive unit (WTRU) configured to communicate through a zero energy (ZE) interface in accordance with an embodiment disclosed herein is provided. The method includes the WTRU receiving, a first positioning reference signal (PRS) resource with parameters characterizing the first PRS and determining the suitability of the first PRS resource for use by the WTRU. The method also includes measuring the phase difference of arrival (PDOA) for available frequency pairs and generating a range estimate based on the PDOA measurement. Further, the method includes the WTRU evaluating a reliability of the PDOA measurement and an accuracy of the range estimate and, on a condition that a sufficient accuracy has been achieved, reporting the range estimate.

A method for use in a wireless transmit/receive unit (WTRU) configured to communicate through a zero energy (ZE) interface in accordance with an embodiment disclosed herein is provided. The method includes the WTRU receiving, a first positioning reference signal (PRS) resource with parameters characterizing the first PRS and determining the suitability of the first PRS resource for use by the WTRU. The method also includes measuring the phase difference of arrival (PDOA) for available frequency pairs and generating a range estimate based on the PDOA measurement. Further, the method includes the WTRU evaluating a reliability of the PDOA measurement and an accuracy of the range estimate and, on a condition that a sufficient accuracy has been achieved, reporting the range estimate.

A type I phase locked loop (PLL) includes an oscillator and a feedback path to a phase detector. The PLL is configured to lock a first frequency and first relative phase of a first output signal to a frequency and a phase of a first input signal, and lock a second frequency and second relative phase of a second output signal to a frequency and a phase of a second input signal. A steady state phase lag of the PLL resulting from the difference between the first frequency and the second frequency is estimated, and the estimated steady state phase lag is used to determine a total phase shift (ΔΦ.sub.LO,steady) between the second input signal and the second output signal. The PLL for the phase shift can be compensated. The determined total phase shift can be used in a distance estimation.

The disclosed computer-implemented method may include transmitting, by at least one radar device, to at least one transponder located within a physical environment surrounding a user, a frequency-modulated radar signal that has a first type of polarization, and receiving, by the at least one radar device, signals that have a second type of polarization, the second type of polarization being different than the first type of polarization, detecting, by a processing device communicatively coupled to the at least one radar device, a signal that has the second type of polarization and was returned to the at least one radar device from the at least one transponder in response to the frequency-modulated radar signal, and calculating, by the processing device, a distance between the at least one transponder and the at least one radar device. Various other methods, systems, and computer-readable media are also disclosed.