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.

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.

A method and system for identification of an item is provided, wherein the system comprises includes a conveyor belt, a conveyor belt controller and a reader operable to receive at least one reading from at least one tag attached to the item and extract from the reading a measurement of the phase of the signal transmitted by the tag and received at at least one antenna of the reader, the antenna being adapted to be arranged at a read point along the conveyor belt, wherein the conveyor belt controller is configured to start the conveyor belt at a first time instant, after the item has been placed on the conveyor belt, and to stop the conveyor belt at a second time instant, when the item has passed the antenna of the reader.

A storage medium-compatible communications unit, a phase detection unit, a parameter acquisition section and a location detection section are provided. The storage medium-compatible communications unit communicates with a storage medium by wireless using electromagnetic waves at a predetermined frequency. The phase detection unit detects phases of signals received from the storage medium. The parameter acquisition section acquires a distance detection parameter to be used in detecting a storage medium distance from a first position of an antenna to the storage medium. The first position is a position in a range of positions of the antenna from which the distance to the storage medium is shortest. The distance detection parameter is a value set in accordance with a positional relationship between the first position and a second position. The second position is a position of the antenna in the range of positions of the antenna that is different from the first position. The location detection section detects the storage medium distance, using a first phase detected by the phase detection unit at the first position, a second phase detected by the phase detection unit at the second position, and the distance detection parameter acquired by the parameter acquisition section. The location detection section identifies the first position at a time at which a trend of changes of phase detected by the phase detection unit in association with movement of the antenna reverses.

A storage medium-compatible communications unit, a phase detection unit, a parameter acquisition section and a location detection section are provided. The storage medium-compatible communications unit communicates with a storage medium by wireless using electromagnetic waves at a predetermined frequency. The phase detection unit detects phases of signals received from the storage medium. The parameter acquisition section acquires a distance detection parameter to be used in detecting a storage medium distance from a first position of an antenna to the storage medium. The first position is a position in a range of positions of the antenna from which the distance to the storage medium is shortest. The distance detection parameter is a value set in accordance with a positional relationship between the first position and a second position. The second position is a position of the antenna in the range of positions of the antenna that is different from the first position. The location detection section detects the storage medium distance, using a first phase detected by the phase detection unit at the first position, a second phase detected by the phase detection unit at the second position, and the distance detection parameter acquired by the parameter acquisition section. The location detection section identifies the first position at a time at which a trend of changes of phase detected by the phase detection unit in association with movement of the antenna reverses.

When measuring a distance between communication apparatuses, influence by a frequency offset between communication apparatuses is suppressed.

A communication apparatus includes a frequency offset acquisition unit, a time acquisition unit, a phase acquisition unit, and a distance generation unit. The frequency offset acquisition unit acquires a frequency offset between frequencies used for transmission/reception by respective ones of the communication apparatuses. The time acquisition unit acquires transmission/reception time between the communication apparatuses. The phase acquisition unit acquires a phase relationship between frequencies used for transmission/reception. The distance generation unit generates distance information on the basis of the phase relationship.

When measuring a distance between communication apparatuses, influence by a frequency offset between communication apparatuses is suppressed.

A communication apparatus includes a frequency offset acquisition unit, a time acquisition unit, a phase acquisition unit, and a distance generation unit. The frequency offset acquisition unit acquires a frequency offset between frequencies used for transmission/reception by respective ones of the communication apparatuses. The time acquisition unit acquires transmission/reception time between the communication apparatuses. The phase acquisition unit acquires a phase relationship between frequencies used for transmission/reception. The distance generation unit generates distance information on the basis of the phase relationship.

An access system for a vehicle includes a receiver and an access module. The receiver is configured to receive a signal transmitted from a portable access device to the vehicle. The access module is configured to: generate a differentiated signal based on the received signal; up-sample the differentiated signal to generate a first up-sampled signal; obtain or generate an expected signal; up-sample the expected signal to generate a second up-sampled signal; cross-correlate the first up-sampled signal and the second up-sampled signal to generate a cross-correlation signal; based on the cross-correlation signal, determine a phase difference between the first up-sampled signal and the second up-sampled signal; determine a round trip time of the signal received by the receiver; and permit access to the vehicle based on the round trip time.

An access system for a vehicle includes a receiver and an access module. The receiver is configured to receive a signal transmitted from a portable access device to the vehicle. The access module is configured to: generate a differentiated signal based on the received signal; up-sample the differentiated signal to generate a first up-sampled signal; obtain or generate an expected signal; up-sample the expected signal to generate a second up-sampled signal; cross-correlate the first up-sampled signal and the second up-sampled signal to generate a cross-correlation signal; based on the cross-correlation signal, determine a phase difference between the first up-sampled signal and the second up-sampled signal; determine a round trip time of the signal received by the receiver; and permit access to the vehicle based on the round trip time.

Example embodiments relate to methods for distance determination. One embodiment includes a method for determining a distance between a first radio signal transceiver and a second radio signal transceiver. The method includes receiving a first set and a second set of measurement results. The first set is acquired by the first radio signal transceiver based on signals transmitted from the second radio signal transceiver and the second set is acquired by the second radio signal transceiver based on signals transmitted from the first radio signal transceiver. The first set is representable as including, for each of a plurality of frequencies, a measurement pair. The method also includes calculating, for each frequency of the plurality of frequencies, a preliminary estimate of a value proportional to a one-way frequency domain channel response. Additionally, the method includes determining a final estimate of the value proportional to the one-way frequency domain channel response.