New sequences have been proposed and/or adopted for short Physical Uplink Control Channel communications between base stations and UEs. In an exemplary embodiment, a UE communicates with a base station based on sequence groups that include the new sequences, where the new sequences are allocated to different sequence groups based, at least in part, on correlations with other existing sequences included in individual sequence groups.

A method and apparatus of distortion compensation during data transmission uses an interweaved look-up table (ILUT) to mitigate residual signal distortions in a signal transmitted over a transmission link. The ILUT interweaves states across both an I and a Q tributary to calculate mean error and an extended symbol basis. As a result, the method works particularly well against two-dimensional distortions like nonlinearity, IQ-imbalance, and quadrature error. The method may be used for either pre-compensation when it is combined with k-means clustering in a transmitter or post-compensation when it is combined with maximum likelihood (ML) detection in a receiver.

New sequences have been proposed and/or adopted for short Physical Uplink Control Channel communications between base stations and UEs. In an exemplary embodiment, a UE communicates with a base station based on sequence groups that include the new sequences, where the new sequences are allocated to different sequence groups based, at least in part, on correlations with other existing sequences included in individual sequence groups.

A digital signal processing, DSP, unit (10) for use in a coherent optical receiver for an optical communications network. The DSP unit comprises an adaptive equaliser (12) and a processing block (22). The equaliser (12) comprises input ports for receiving electrical signals, each corresponding to a different state of polarization of an optical signal received by the coherent optical receiver,and output ports,each connected to a processing branch (14). A processing branch comprises a symbol sequence estimator, SSE, (16) and a carrier phase estimator, CPE, (18) comprising an input for receiving signal taped from an output of the processing branch. An output of the CPE is connected to a phase adjuster (20) interconnecting the respective output port of the equaliser and the SSE. The processing block (22) is connected to an output of the CPE,an output of the processing branch and at least one of the output of the phase adjuster and the outputs of the equalizer.

Aspects of the present invention include apparatus and methods for transmitting and receiving signals in communication systems. A multicarrier generator generates a multicarrier signal. An optical demultiplexer separates the multicarrier signal into separate multicarrier signals. At least one QPSK modulator modulates signals from the separate multicarrier signals. An optical multiplexer combines the QPSK modulated signals into a multiplexed signal. The multiplexed signal is then transmitted.

Methods, systems, and devices for wireless communication are described. A wireless communication device may receive multiple data streams from one or more users, associate the multiple data streams with different user groups, and identify modulation symbols for the users after reducing signal contribution from modulation symbols associated with different user groups. For example, the device may receive a signal including multiple spatial streams, partition the data streams into different user groups, and determine a set of sequences from channel characteristics associated with the respective user groups. The wireless communication device may then apply the sequences to the received signal and to values associated with the channel characteristics. Subsets of values may be selected following the application of the sequences, and from the subsets of values, the wireless communication device may identify the sets of modulation symbols associated with one or more of the user groups.

A communication method, a communications apparatus, and a storage medium are disclosed, to reduce a probability that consecutive bit errors occur in a communications system. A received to-be-sent signal is modulated to obtain a modulated signal, and N rounds of operations are further performed on the modulated signal to obtain an encoded signal. An output of the 1.sup.st-round operation in the N rounds of operations is determined based on the modulated signal and an output that is of the N.sup.th-round operation and that is processed by a first delay circuit, and an output of the i.sup.th-round operation in the N rounds of operations is determined based on an output of the (i−1).sup.th-round operation and an output that is of the N.sup.th-round operation and that is processed by a second delay circuit, where i is an integer greater than 1 and less than or equal to N.

A method, apparatus and system for implementing pre-equalization equalizer tap analysis and correlation in a DOCSIS 3.1 network environment. The disclosed principles improve the pre-equalization analysis in the DOCSIS 3.1 environment by filtering out short distance reflections, which is required for the proper grouping and correlation of modems.

A method for detecting a sent sequence, a receiver, and a receiving device in order to simplify an algorithm for detecting a sent sequence and improve detection efficiency. The method for detecting a sent sequence includes determining a maximum possible candidate value of each element in N elements of a received element sequence to obtain N maximum possible candidate values, where N is a positive integer, determining state sequences corresponding to the N maximum possible candidate values as reserved sequences to obtain N groups of reserved sequences, performing likelihood computation on the N groups of reserved sequences, and setting a reserved sequence that is in the N groups of reserved sequences and is most consistent with the element sequence as a detected sent sequence.

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.