A control method for a decision feedback equalizer (DFE) includes: generating a channel impulse response (CIR) estimation vector according to an input signal at a CIR estimation frequency; generating an FFE coefficient according to the CIR estimation vector at a first frequency; generating an FBE coefficient according to the CIR estimation vector, and the FFE coefficient at a second frequency; generating a feed-forward equalization filtered result according to the input signal and the FFE coefficient; generating a feed-backward equalization filtered result according to a decision signal and the FBE coefficient; and generating an updated decision signal according to the feed-forward equalization filtered result and the feed-backward equalization filtered result. At least one of the first frequency and the second frequency is smaller than the CIR estimation frequency.

The present invention relates to a method and apparatus for channel estimation between a transmitter and a receiver in a wireless communications system. In one arrangement, the method comprises: receiving at the receiver a first sequence of bits representing a first sequence of coded symbols transmitted over the communications channel; decoding the first sequence of coded symbols using maximum-likelihood based decoding including: generating traceback outcomes by tracing backwards the first sequence of bits through a maximum-likelihood based traceback path, the traceback outcomes including a first portion associated with a first traceback depth and a second portion associated with a second traceback depth that is deeper than the first traceback depth; generating a channel estimate of the communications channel based on the first portion of the traceback outcomes; and generating an estimate of at least some information bits coded in the first sequence of coded symbols based on the second portion of the traceback outcomes.

A spectrally efficient low complex Orthogonal Time Frequency Space (OTFS) modulation-based transceiver system and method is provided. The system and method are developed for uplink and downlink wireless communication for resource-constrained IoT and M2M devices. The transceiver system includes at least one transmitter configured to transmit bit stream using adaptive Orthogonal Time Frequency Space (OTFS) frame with selectively embedded pilot depending on mobility condition for improving spectral efficiency and at least one receiver configured to dispose onto IoT devices for receiving the transmitted bit stream. The receiver updates the transmitter about mobility condition of said at least one receiver through a control channel.

A control method for a decision feedback equalizer (DFE) includes: generating a channel impulse response (CIR) estimation vector according to an input signal at a CIR estimation frequency; generating an FFE coefficient according to the CIR estimation vector at a first frequency; generating an FBE coefficient according to the CIR estimation vector, and the FFE coefficient at a second frequency; generating a feed-forward equalization filtered result according to the input signal and the FFE coefficient; generating a feed-backward equalization filtered result according to a decision signal and the FBE coefficient; and generating an updated decision signal according to the feed-forward equalization filtered result and the feed-backward equalization filtered result. At least one of the first frequency and the second frequency is smaller than the CIR estimation frequency.

A receiver applies a calibration method to compensate for skew between input channels. The receiver skew is estimated by observing the coefficients of an adaptive equalizer which adjusts the coefficients based on time-varying properties of the multi-channel input signal. The receiver skew is compensated by programming the phase of the sampling clocks for the different channels. Furthermore, during real-time operation of the receiver, channel diagnostics is performed to automatically estimate differential group delay and/or other channel characteristics based on the equalizer coefficients using a frequency averaging or polarization averaging approach. Framer information can furthermore be utilized to estimate differential group delay that is an integer multiple of the symbol rate. Additionally, a DSP reset may be performed when substantial signal degradation is detected based on the channel diagnostics information.

An interference processing method comprises: receiving a multi-carrier modulated signal, wherein the multi-carrier modulated signal comprises multi-carrier modulation symbols; discomposing the multi-carrier modulation symbols into a set of subcarriers, wherein the set of subcarriers at least comprises a target subcarrier; equalizing the target subcarrier to obtain an equalized target subcarrier; obtaining an error power of the equalized target subcarrier; and comparing the error power of the equalized target subcarrier with a predefined threshold to determine the existence of interference in the target subcarrier, wherein the predefined threshold is associated with a minimum distance between two constellation points of a modulation constellation of the target subcarrier.

A wireless communication system is described which includes a transmitter operable to transmit a transmitted signal, the transmitter having one or more transmitting antennae, a receiver operable to receive a received signal, the receiver having one or more receiving antennae, wherein lattice reduction is used in obtaining, at the receiver, an estimate of the transmitted signal based on the received signal, characterized in that the lattice reduction utilizes a lattice reduction matrix, a decomposed representation of which is transmitted between the transmitter and the receiver.

Systems, methods, and devices reduce and mitigate spurs that may occur in transmit waveforms of wireless communications devices. Methods include beginning transmission of a portion of a data packet from a baseband layer of a wireless communications device, and generating a spur canceling signal based on an estimated magnitude and an estimated phase of a spur signal at identified spur frequencies of a frequency band used for the transmission. Methods also include subtracting the spur canceling signal from the transmission of the portion of the data packet, and generating a transmitted signal based on the subtracting such that the spur canceling signal is subtracted during the transmission of the portion of the data packet.