Aspects of the present disclosure may involve use of a radio frequency receiver and in such a receiver, tracking multipath gains and delays of multipath reflections corresponding to an OFDM multipath transmission channel. The gains and delays are based on time-domain evolution of the channel impulse response. Multipath reflections are searched for and then used to calculate channel correlation information to provide channel estimations to aid in mitigating or cancelling distortion of the received signal.

A system for peak-to-average-power ratio (PAPR) reduction of a frequency shifted plurality of digital broadcast signals taking into account the combined signal peaks in order to transmit the signals more efficiently in a single broadcast transmission system. The PAPR algorithm takes into account a rotating constellation phase offset for the shifted signals corresponding to the amount of applied frequency shift. In the case of a dual sideband In-Band-On-Channel (IBOC) signal typically used in conjunction with an FM carrier in the center, the sidebands can be interleaved to create a new IBOC signal definition and take the place of the FM carrier for an all-digital transmission that is backward compatible with IBOC receivers allowing for a gradual migration to all digital broadcasting.

There is provided a method of transmitting and receiving data across a network. A receiver device comprises a recovery module comprising a neural network trained to recover signals from clipped signals. The transmitter device may clip the original signal more aggressively due to the improved performance of the machine-learning based recovery module, thereby reducing the Peak to Average Power Ratio (PAPR) of the signal.

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 multiple access method, a multiple access transmitter, and a multiple access receiver includes performing, by a transmitter, channel coding on a bit sequence to determine a coded sequence. The method also includes interleaving and/or scrambling the coded sequence, and performing multidimensional constellation modulation on the interleaved and/or scrambled sequence; performing grid mapping on the modulated symbol sequence to determine a mapped sequence, and transmitting the mapped sequence. The method also includes receiving, by a receiver, mixed signals from multiple transmitters, the mixed signals are obtained by performing, by each of the multiple transmitters, interleaving and/or scrambling, multidimensional constellation modulation and grid mapping on data. The method further includes decoding, by the receiver, mixed information according to interleaver information and/or scrambler information, multidimensional constellation information and grid mapping pattern information corresponding to each transmitter to obtain data corresponding to each transmitter.

When an OFDM radio system which uses a wide frequency band is interfered with by another narrow-band radio system, the interference can frequently be compensated but the transmission quality decreases drastically. Thus, narrow-band interferers in an OFDM radio system are determined according to the invention whereby none of the subscribers of the radio system transmits in a defined time slot or scan slot but all switch at the same time into the receiving mode. If there is interference (P1, P2), it is detected in this time slot. Countermeasures are taken individually in all the mobile devices, in particular the detection of the frequency and strength of the narrowband interference (P1, P2) and the configuration of a flexible notch filter (140) in the time range to the detected frequency and strength. The scanned received signal (RXS) is then filtered in the time range, i.e. before the FFT (120) and the OFDM channel estimation (130) by the correspondingly configured notch filter (140). The notch (S1, S2) of the notch filter thereby acts in the transmission function like a natural break when receiving data.

Examples described herein include systems and methods which include wireless devices and systems with examples of cross correlation including symbols indicative of radio frequency (RF) energy. An electronic device including a statistic calculator may be configured to calculate a statistic including the cross-correlation of the symbols. The electronic device may include a comparator configured to provide a signal indicative of a presence or absence of a wireless communication signal in the particular portion of the wireless spectrum based on a comparison of the statistic with a threshold. A decoder/precoder may be configured to receive the signal indicative of the presence or absence of the wireless communication signal and to decode the symbols responsive to a signal indicative of the presence of the wireless communication signal. Examples of systems and methods described herein may facilitate the processing of data for wireless communications in a power-efficient and time-efficient manner.

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.

A method for estimating a time of arrival of a signal transmitted over a wireless channel, includes receiving the signal by a receiving device; correlating the received signal with a filtered code sequence to create a correlation output, identifying in the correlation output, an observation window associated with a main lobe in the correlation output; and processing the observation window to determine a time of arrival of a first path component in the received signal. The filtered code sequence is formed by incorporating a time of arrival matched filter (TOA-MF) inside predetermined shaped code sequence. The TOA-MF is matched to the predetermined shaped code sequence and is based upon a power delay profile of the wireless channel. The predetermined shaped code sequence is a convolution of a predetermined shaping sequence and a predetermined code sequence.

Saturation of an A/D converter at a receiver is addressed by forcing a controlled clipping of a peak signal pulse in the analog domain and restoring the pulse using a digital algorithm within the receiver. An A/D converter saturates and clips the peak pulses in the signal. Saturated peaks are restored by an algorithm operating in a baseband digital signal processor that utilizes information related to the time intervals where clipping was applied, along with information associated with the portion of the pulse below the clipping threshold. The time interval information is available from the A/D converter or through use of a separate pulse clipping detection algorithm. Through the use of embodiments of the present invention, the effect of signal clipping on receiver performance is reduced and therefore allows for increased clipping of the received signal.