The present application discloses a signal sampling and recovery method and apparatus applicable to an OvXDM system, and the OvXDM system. The method includes: constructing, based on design parameters, an observation matrix that is irrelevant to an original signal y, wherein the observation matrix is a two-dimensional M*S matrix, S is a length of the original signal y, and M is smaller than S; compressing the original signal y based on a formula Y.sub.cs=Y, to obtain a M*1 compressed signal Y.sub.cs, wherein Y is a S*1 column vector that is obtained according to the original signal y; and reconstructing the compressed signal Y.sub.cs based on a predetermined algorithm, so as to recover the original signal y. The present application implements accurate recovery of the original signal at a reduced sampling rate, thereby reducing hardware requirements of the system and improving feasibility of the technical solution.

A transmitter for transmitting an output signal includes first and second filter structures. The first filter structure includes a first combiner to extend a first data signal by a first reference signal to obtain a first extended data signal, and a first IIR filter for filtering the first extended data signal to obtain a first filtered data signal. The second filter structure includes a second combiner to extend a second data signal by a second reference signal, and a second IIR filter for filtering the second extended data signal. The transmitter includes a multiplexer for combining the first and second filtered data signals to obtain the output signal. A system response of the first IIR filter based on the first reference signal corresponds to a system response of the second IIR filter based on the second reference signal.

A system and method for a high-speed transmitter comprising a precoder configured to receive a sequence of input symbols and to generate for each received symbol a respective recoded symbol is disclosed. The transmitter includes a recoding unit configured for recoding each current received PAM-M based on the recoded symbol immediately preceding the current recoded symbol at the recoding unit, a shift unit configured for determining a shift value for each current received symbol from the recoding unit based on the symbol received from the recoding unit and immediately preceding the current symbol at the shift unit; and Feed-Forward Equalizer unit for applying the shift values to the respective symbols received from the recoding unit to generate a corresponding sequence of output symbols to be transmitted in an output stream.

Simple, low-cost systems and methods allow to shape the output spectrum of pre-equalized Tomlinson Harashima Precoding (THP)-equalized transmitters in a manner such as to create a relatively narrow DC null to facilitate transmission over DC-null channels in AC-coupled communication channels. Advantageously, this may be accomplished without significantly adding to the peak value of the to-be-transmitted signal and without the need to resort to high-order filters in the signal path or the use of recursive taps to compensate such filters.

Examples described herein relate to an Ethernet physical layer transceiver (PHY) circuitry for use in frame communication with a remote link partner. In some example, the Ethernet PHY circuitry can include Physical Medium Dependent (PMD) circuitry and transmitter circuitry and receiver circuitry for use in the frame communication. In some examples, the PMD circuitry is to perform link training with a partner transmitter and selectively request the partner transmitter to apply a modulation scheme with precoding during the link training based on a magnitude of one or more equalizer coefficient values.

A LLR calculation unit includes a range detection unit that detects a range in which a received signal resulting from a modulo operation is present among a plurality of ranges defined on the basis of a boundary value in the modulo operation; a coefficient determination unit that determines a coefficient to be used for calculation of a log-likelihood ratio for a most significant bit in quadrature amplitude modulation of the received signal resulting from the modulo operation on the basis of a result of detection by the range detection unit; and an LLR computation unit that calculates the log-likelihood ratio for the most significant bit by using the received signal resulting from the modulo operation and the coefficient.

A system and method for a high-speed transmitter comprising a precoder configured to receive a sequence of input symbols and to generate for each received symbol a respective recoded symbol is disclosed. The transmitter includes a recoding unit configured for recoding each current received PAM-M based on the recoded symbol immediately preceding the current recoded symbol at the recoding unit, a shift unit configured for determining a shift value for each current received symbol from the recoding unit based on the symbol received from the recoding unit and immediately preceding the current symbol at the shift unit; and Feed-Forward Equalizer unit for applying the shift values to the respective symbols received from the recoding unit to generate a corresponding sequence of output symbols to be transmitted in an output stream.

A method for signal transmission using precoded symbol information involves estimating a two-dimensional model of a communication channel in a delay-Doppler domain. A perturbation vector is determined in a delay-time domain wherein the delay-time domain is related to the delay-Doppler domain by an FFT operation. User symbols are modified based upon the perturbation vector so as to produce perturbed user symbols. A set of Tomlinson-Harashima precoders corresponding to a set of fixed times in the delay-time domain may then be determined using a delay-time model of the communication channel. Precoded user symbols are generated by applying the Tomlinson-Harashima precoders to the perturbed user symbols. A modulated signal is then generated based upon the precoded user symbols and provided for transmission over the communication channel.

Embodiments of the invention provide a signal transmission method of a wireless communication system, the method comprising: selecting a phase compensation value for a k-th layer of user data of the wireless communication system, performing, according to the phase compensation value, phase rotation on a reference signal in the k-th layer user data, so that a signal power of the reference signal, after performing interference mitigation thereon at a transmission end, does not exceed a predetermined power threshold, wherein, k is selected from 1 to M, and M is less than or equal to K, and K is the total number of layers of user data of the wireless communication system; and transmitting, through a wireless channel, the reference signal after the phase rotation.

The invention provides an optical interconnect system and method for a data center. A nonlinear differential precoding module performs nonlinear differential precoding on an inputted original signal, to obtain a precoded signal with an increased quantity of levels. A generalized Tomlinson-Harashima precoding (GTHP) module pre-equalizes the precoded signal, to obtain a pre-equalized signal with scattered distribution. A faster than Nyquist (FTN) module performs high-frequency truncation filtering on the pre-equalized signal, to obtain a discrete signal. A signal transmission module transmits the discrete signal from a transmitting end to a receiving end. A feed-forward equalizer (FFE) performs strong equalization on the discrete signal to obtain a level slice signal, and decodes the level slice signal according to a GTHP decoding table, to obtain a decoded signal. A simplified 2D constellation distortion module processes the decoded signal to reshape a constellation, and obtains a restored signal according to a time interleaving method.