Utilizing a fast Fourier transform (FFT) to cancel a non-liner phase response of a digital infinite impulse response (IIR) lowpass filter is presented herein. An apparatus generates, via the digital IIR lowpass filter, respective discrete time domain orthogonal frequency-division multiplexing (OFDM) based digital output values comprising non-linear phase distortion; in response to removing respective cyclic prefix values from the respective discrete time domain OFDM based digital output values to obtain a group of discrete time domain OFDM based digital output values, generates, based on such values via a digital FFT, respective frequency domain OFDM based digital output values comprising a non-linear phase response of the digital FFT; and based on the non-linear phase response of the digital IIR lowpass filter, applies phase compensation to the respective frequency domain OFDM based digital output values to obtain frequency compensated frequency domain OFDM based digital output values comprising a linear phase response.

A terminal receives a slot that includes a plurality of symbols. The terminal determines the number of symbols included in a sub-frame on the basis of a time length of the symbol.

Systems, apparatuses, and methods for enhancement for amplify-and-forward relay. Instead of merely passing received signal from a source, relay may equalize the received signal based on reference signal contained in the received signal, before amplifying and transmitting the signal to a destination. Compared to amplify-and-forward, equalize-and-forward may compensate the received source signal for various imperfections such as channel distortions and phase errors, using demodulation reference signal and phase tracking reference signal. The relay may apply Fast Fourier Transform (FFT) to equalize the signal in tone domain.

Methods, systems and devices for lattice reduction in decision feedback equalizers for orthogonal time frequency space (OTFS) modulation are described. An exemplary wireless communication method, implementable by a wireless communication receiver apparatus, includes receiving a signal comprising information bits modulated using OTFS modulation scheme. Each delay-Doppler bin in the signal is modulated using a quadrature amplitude modulation (QAM) mapping. The method also includes estimating the information bits based on an inverse of a single error covariance matrix of the signal, with the single error covariance matrix being representative of an estimation error for all delay-Doppler bins in the signal.

Methods and systems are presented for correcting interference to audio transmissions containing data. In one embodiment, a method is presented that includes receiving an audio transmission that includes data modulated onto an audio carrier signal. A first portion of the audio transmission may be detected that includes predetermined frequencies that are produced at predetermined times. The method may further include determining a frequency distribution for the predetermined frequencies and identifying magnitudes of the predetermined frequencies within the frequency distribution. A second portion of the audio transmission may then be equalized according to the magnitudes of the predetermined frequencies.

Embodiments of the present disclosure provide a method, device, and computer readable medium for channel equalization. The method comprises receiving, at a first device, a first signal from a second device via a plurality of subcarriers over a communication channel; sampling the first signal to obtain sampled symbols; and generating a second signal based on the obtained sampled symbols using a direct association between sampled symbols and payloads, the second signal indicating a payload of the first signal carried on an effective subcarrier of the plurality of subcarriers. Through the use of the direct association between sampled symbols and payloads, it is possible to achieve channel equalization in a less complicated, more reliable, and cost-effective manner, so as to extract the payload in the received signal.

Techniques are described for pre-equalization at the demodulator of a satellite receiver terminal to compensate for forward link distortions. Some satellite channel filters can manifest distortions, such as asymmetric group delay response. Such distortions can conventionally force restriction of symbol rate only to the portion of the channel bandwidth having a symmetric filter response. Embodiments include a pre-equalizer in the demodulation path that filters received downlink communications based on a set of pre-equalizer filter coefficients computed to at least partially compensate for the channel filter distortions. Some embodiments support updating the filter coefficients based on channel reassignments, and/or dynamically updating the filter coefficients based on detecting and exploiting pre-equalization frames. The pre-equalized sample stream can facilitate reliable decoding by the demodulator with an appreciably increased symbol rate and correspondingly increased forward link capacity.

A high-speed data receiver includes interleaver circuitry configured to divide a received data stream into a plurality of interleaved paths for processing, spectral content detection circuitry configured to derive spectral content information from data on each of the plurality of interleaved paths, sorting circuitry configured to bin the derived spectral content information according to energy levels, stream attribute determination circuitry configured to determine, based on sorted spectral content, one or more of path offsets of the interleaved paths, gain mismatch among interleaved paths, signal bandwidth mismatch and pulse width mismatch, and equalization circuitry configured to correct the one or more of the determined offsets, the determined gain mismatch and the determined signal width mismatch. Equalization circuitry may be configured to equalize a gain-normalized signal by separately adjusting respective bandwidth actuators of each respective interleaved path and respective pulse width actuators of each respective interleaved path.

A Belief Propagation (BP) equalization method and apparatus, a communication device and a storage medium are disclosed. The method may include: splitting a received signal Y.sub.c, a channel estimation H.sub.c and a symbol estimation X.sub.c into real parts and imaginary parts to obtain a received signal matrix Y, a channel estimation matrix H and a symbol estimation matrix X (S101); performing orthogonal triangular (QR) decomposition on the channel estimation matrix H to obtain an equivalent received signal Y.sub.bp, an equivalent channel R and a noise power σ.sup.2 (S102); and performing iteration based on the equivalent received signal Y.sub.bp, the equivalent channel R and the noise power σ.sup.2 to obtain a position probability of per stream symbol (S103).

The disclosed systems, structures, and methods are directed to a single-stage frequency-domain equalization (FDEQ) structure implemented on a processor, comprising a data preprocessing unit configured to concatenate received data samples in time-domain digital signals, transform the concatenated data samples in the time-domain digital signals to frequency-domain digital signals, and an adaptive equalizer comprising 2×2 multiple-input multiple output (MIMO) configured to compensate for non-time-varying fixed impairments and time-varying adaptive impairments in the frequency-domain digital signals.