A phase rotation amount of each of subcarriers is calculated by calculating a difference between the first phase difference and the second phase difference between consecutive subcarriers included in radio signals, and performing phase addition processing based on the difference. A characteristic coefficient regarding a change rate of the phase rotation amount of each of the subcarriers with respect to a frequency is calculated by performing a linear regression analysis of the relationship between a frequency and the phase rotation amount, and a distance is estimated based on the characteristic coefficient.

A wireless communication apparatus includes components below. An equalization unit performs equalization processing on a part of a received signal corresponding to a first range and a part of the received signal corresponding to a second range. The first range includes detection target data. The second range is outside the first range. A replica generation unit decomposes the second range, on which equalization processing has been performed, into a plurality of signal components, and reproduces the part of the received signal corresponding to the second range for each of the signal components to generate a replica of an interference component. An interference cancellation unit cancels the interference component from the part of the received signal corresponding to the first range by using the replica. A data extraction unit extracts the detection target data from the received signal.

The method includes configuring a first CLI-RS configuration at a first UE (200a). Further, the method includes configuring a second CLI-RS configuration at a second UE (200b). Further, the method includes generating a CLI-RS sequence using a common CLI-RS reference point known to the first UE (200a) and the second UE (200b). Further, the method includes filling the CLI-RS sequence in the first set of CLI-RS resources indicated in the first CLI-RS configuration. Further, the method includes transmitting the CLI-RS sequence filled in the first set of CLI-RS resources indicated in the first CLI-RS configuration to the second UE (200b). Further, the method includes receiving the CLI-RS sequence transmitted by the first UE (200a). Further, the method includes processing the received CLI-RS sequence based on the second CLI-RS configuration.

Using a phase interferometry method which utilizes both amplitude and phase allows the determination and estimation of multipath signals. To determine the location of an object, a signal that contains sufficient information to allow determination of both amplitude and phase, like a packet that includes a sinewave portion, is provided from a master device. A slave device measures the phase and amplitude of the received packet and returns this information to the master device. The slave device returns a packet to the master that contains a similar sinewave portion to allow the master device to determine the phase and amplitude of the received signals. Based on the two sets of amplitude and phase of the RF signals, the master device utilizes a fast Fourier transform or techniques like multiple signal classification to determine the indicated distance for each path and thus more accurately determines a location of the slave device.

Techniques are described for carrier frequency offset (CFO) and channel estimation of orthogonal frequency division multiplexing (OFDM) transmissions over multiple-input multiple-output (MIMO) frequency-selective fading channels. A wireless transmitter forms blocks of symbols by inserting training symbols within two or more blocks of information-bearing symbols. The transmitter applies a hopping code to each of the blocks of symbols to insert a null subcarrier at a different position within each of the blocks of symbols, and a modulator outputs a wireless signal in accordance with the blocks of symbols. A receiver receives the wireless signal and estimates the CFO, and outputs a stream of estimated symbols based on the estimated CFO.

A system that incorporates aspects of the subject disclosure may perform operations including, for example, receiving, via an antenna, a signal generated by a communication device, detecting passive intermodulation interference in the signal, the interference generated by one or more transmitters unassociated with the communication device, and the interference determined from signal characteristics associated with a signaling protocol used by the one or more transmitters. Other embodiments are disclosed.

Methods and apparatus are disclosed for processing interference due to passive non-linear products of transmitted signals in a wireless network, and more specifically, but not exclusively, to reduction of interference caused to a receiver due to passive intermodulation (PIM) products generated from at least a first Multiple Input Multiple Output (MIMO) signal comprising first and second MIMO component streams at a first carrier frequency. In other scenarios, there may be two or more carrier frequencies combining to cause PIM, and each carrier frequency may have two or more MIMO component streams.

A system that incorporates aspects of the subject disclosure may perform operations including, for example, receiving, via an antenna, a signal generated by a communication device, detecting passive intermodulation interference in the signal, the interference generated by one or more transmitters unassociated with the communication device, and the interference determined from signal characteristics associated with a signaling protocol used by the one or more transmitters. Other embodiments are disclosed.

A wireless communication apparatus includes components below. An equalization unit performs equalization processing on a part of a received signal corresponding to a first range and a part of the received signal corresponding to a second range. The first range includes detection target data. The second range is outside the first range. A replica generation unit decomposes the second range, on which equalization processing has been performed, into a plurality of signal components, and reproduces the part of the received signal corresponding to the second range for each of the signal components to generate a replica of an interference component. An interference cancellation unit cancels the interference component from the part of the received signal corresponding to the first range by using the replica. A data extraction unit extracts the detection target data from the received signal.

A method for estimating a nonlinear self-interference channel in a wireless channel system, according to the present invention, can further comprise the steps of: applying a first sequence to a first symbol; applying, to a second symbol, a sequence of which a phase is shifted from that of the first sequence by /2; and transmitting the first symbol and the second symbol.