Aspects of the subject disclosure may include, for example, obtaining data regarding passive intermodulation (PIM) detected in a received communication signal, and performing polarization adjusting for a communications system such that an impact of the PIM on the communications system is minimized. Other embodiments are disclosed.

The invention relates to precoding (or rather pre-equalisation) for a faster-than-Nyquist OFDM or OFDM/OQAM type transmitter. Compression of faster-than-Nyquist OFDM pulses over time introduces an inter-symbol interference (ISI) and a sub-carrier interference (ICI). Assuming a Gaussian-type channel (AWGN), the ISI and ICI can be estimated at the transmitter and, in this way, some of the symbols (at most half) can be precoded (according to the value of the adjacent symbols), such as to cancel the ISI and ICI introduced during transmission and reception.

A method for performing self-interference cancellation by a communication device which uses an FDR mode can comprise the steps of: measuring the strength of a residual self-interference signal, after antenna and analog self-interference cancellation, for each subband with respect to a predetermined number of subbands configured in a communication device; determining the order of a nonlinear self-interference signal component, to be considered for channel estimation of a nonlinear self-interference signal, for each subband on the basis of the strength of the residual self-interference signal that has been measured for each subband; and performing channel estimation of the nonlinear self-interference signal on the basis of the order that has been determined for each subband.

An Alamouti coding method includes mapping real number data symbols to a first subcarrier to an (N/21)th subcarrier, based on indices of the subcarriers, mapping the mapped real number data symbols and real number data symbols constituting an Alamouti coded symbol pair to an (N/2+1)th subcarrier to an (N1)th subcarrier, in a frequency inversion scheme with reference to an (N/2)th subcarrier, adjusting a phase of each real number data symbol mapped to the first subcarrier to the (N/21)th subcarrier, by using a first phase adjustment value, based on indices of the mapped subcarriers and an index of a time interval, and adjusting a phase of each real number data symbol mapped to the (N/2+1)th subcarrier to the (N1)th subcarrier, by using a conjugate value of a first phase adjustment value for a corresponding real number data symbol and the real data symbols constituting the Alamouti coded symbol pair.

Adjacent channel leakage-power ratio (ACLR) can be reduced at a transmitter of a device. A modulated signal can be mapped into a plurality of tone sets in a frequency domain, wherein the plurality of tone sets include a first, a second, and a third set of tones. The first and the third set of tones can be converted in the frequency domain to a fourth and a fifth set of tones, respectively, in a time domain. A zero padding of one or more symbols associated with the fourth and the fifth set of tones can be performed to output a sixth and a seventh set of tones, respectively. The sixth and the seventh set of tones can be converted to an eighth and a ninth set of tones, respectively, in the frequency domain. The eighth and the ninth set of tones can be processed for transmitting to another wireless device.

An inter-carrier interference (ICI) mitigation circuit associated with an orthogonal frequency division multiplexing (OFDM) receiver is disclosed. The ICI mitigation circuit comprises an ICI cancellation circuit configured to receive an OFDM symbol associated with an OFDM signal and determine an ICI associated with one or more OFDM subcarriers within the OFDM symbol. The ICI cancellation circuit is further configured to cancel the ICI from the one or more OFDM subcarriers associated with the OFDM symbol, in order to generate a desired OFDM symbol. In some embodiments, the ICI is determined and cancelled at the ICI cancellation circuit, in accordance with a predetermined ICI mitigation algorithm.

An orthogonal frequency division multiplexing (OFDM) receiver includes detection logic, offset generation logic, tone erasure logic, and correction generation logic. The detection logic is configured to detect a signal containing a block of samples that includes a narrowband interferer from a communication channel. The offset generation logic is configured to align a frequency of the narrowband interferer to a center of a subcarrier frequency of the communication channel to produce an offset signal thereby introducing inter-carrier interference (ICI). The tone erasure logic is configured to remove the subcarrier frequency from the offset signal to produce an interferer erased offset signal. The correction generation logic is configured to remove the ICI to produce an interferer erased signal.

A method of estimating a channel for mobile systems with insufficient cyclic prefix length, wherein the channel comprises a plurality of multipath components (,), includes: receiving a signal (y.sub.n) comprising a plurality of contributions of a transmit signal (x.sub.n[k], x.sub.n-1[k]) transmitted during a plurality of transmission time intervals (n, n1) on a plurality of sub-carriers of known pilots (kP.sub.b) and a plurality of sub-carriers of unknown data (k.Math.P.sub.b); determining an estimate of the plurality of multipath components (,) based on a probabilistic relation between the plurality of first contributions (x.sub.n[k], x.sub.n-1[k]) of the transmit signal, wherein the plurality of first contributions are transmitted during adjacent transmission time intervals (n, n1), and an observation of the received signal (y.sub.n[k]) at a subcarrier (kP.sub.b) of the known pilots, wherein the probabilistic relation is based on statistical properties of the plurality of first contributions (x.sub.n[k], x.sub.n-1[k]) of the transmit signal.

Apparatuses and methods for performing asynchronous multicarrier communications are provided. One such method involves generating, at a first wireless device, a waveform including one or more carriers, shaping the waveform to reduce interference between the waveform and adjacent waveforms, and transmitting, on a spectrum, the shaped waveform asynchronously.

Aspects of the subject disclosure may include, for example, receiving, via an antenna, a communication signal generated by a communication device, and detecting interference in the communication signal, wherein the interference is generated by one or more interference sources, wherein the interference is detected by monitoring a near field region of the antenna, an intermediate field region of the antenna, a far field region of the antenna, or any combinations thereof, wherein the monitoring excludes monitoring only the far field region of the antenna. Other embodiments are disclosed.