A data detection method, having the steps of: a. receiving a signal transmitted over a communication channel, the signal being representative of at least a stream of interfering symbols x.sub.k, each representing one or more bits of a transmitted message; b. filtering the received signal through at least a filter bank having at least a first filter representative of a linear response of the channel and a second filter representative of a non-linear response of the channel, and sampling the filtered signals at the symbol rate, thus obtaining respective sequences of filtered samples r.sub.k.sup.(1) r.sub.k.sup.(3); and c. jointly computing the a posteriori probabilities of N>1 consecutive symbols x.sub.k. A data detector for carrying out such a method, and a method of transmitting data over a nonlinear channel, optimizing spectral efficiency when data detection is performed using such a method is also provided.

A method for equalizing a signal comprising modulated symbols comprising a block of N received symbols comprises: demultiplexing the N received symbols by factor L to generate a predetermined number L of sub-blocks of symbols, each comprising a version of the N received symbols sub-sampled by factor L, the independent equalization of each sub-block using an identical equalization algorithm, multiplexing the equalized symbols of each sub-block to obtain a block of N equalized symbols, removing instances of interference linked to paths other than two paths of higher power comprising generating an interference term resulting from the influence, on the equalized symbols, of all paths of the channel having the impulse response of the transmission channel except two paths of higher power, subtracting the interference term from the symbols of the block of N received symbols, and, a second equalization step equal to a second iteration of the first equalization step.

Disclosed is a relay method including: receiving, as input, respective reception signals by two receive antennas, the reception signals each including a reception signal resulting from multiplexing respective transmission signals transmitted by two transmission antennas in a first frequency band; performing frequency conversion on the reception signal received by one of the receive antennas so as to obtain a signal of a third frequency band; and performing frequency multiplexing on the signal having the third frequency band and the reception signal received by the other of the receive antennas.

An apparatus and method for optimizing the performance of satellite communication system receivers by using the Soft-Input Soft-Output (SISO) BCJR (Bahl, Cocke, Jelinek and Raviv) algorithm to detect a transmitted information sequence is disclosed. A Sliding Window technique is used with a plurality of reduced state sequence estimation (RSSE) equalizers to execute the BCJR algorithm in parallel. A serial data stream is converted into a plurality of data blocks using a serial-to-parallel converter. After processing in parallel by the equalizers, the output blocks are converted back to a serial data stream by a parallel-to-serial converter. A path history is determined using maximum likelihood (ML) path history calculation.

The invention relates to a method for optimizing a capacity of a communication channel in a communication system comprising at least a transmitter (10), a receiver (11), and the communication channel (12) between the transmitter and the receiver. The transmitter (10) uses a finite set of symbols Ω={ω.sub.1, . . . , ω.sub.N} having respective positions on a constellation, to transmit a message including at least one symbol on said communication channel (11). The communication channel (11) is characterized by a conditional probability distribution ρ.sub.Y|X(y|x), where y is the symbol received at the receiver (12) while x is the symbol transmitted by the transmitter. More particularly, the conditional probability distribution ρ.sub.Y|X(y|x) is obtained, for each possible transmitted symbol x, by a mixture model using probability distributions represented by exponential functions. An optimized input distribution p.sub.x(x) is computed, based on parameters of the mixture model, to define optimized symbols positions and probabilities to be used at the transmitter for optimizing the capacity of the channel.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a client may select, based at least in part on a classifier, an autoencoder of a set of autoencoders to be used for encoding an observed wireless communication vector to generate a latent vector. The client may transmit the latent vector and an indication of the autoencoder. Numerous other aspects are provided.

The present disclosure provides techniques for bandwidth constrained communication systems with frequency domain information processing. A bandwidth constrained equalized transport (BCET) communication system can include a transmitter, a communication channel, and a receiver. The transmitter can include a pulse-shaping filter that intentionally introduces memory into a signal in the form of inter-symbol interference, an error control code (ECC) encoder, a multidimensional fast Fourier transform (FFT) processing block that processes the signal in the frequency domain, and a first interleaver. The receiver can include an information-retrieving equalizer, a deinterleaver with an ECC decoder, and a second interleaver joined in an iterative ECC decoding loop. The communication system can be bandwidth constrained, and the signal can comprise an information rate that is higher than that of a communication system without intentional introduction of the memory at the transmitter.

A receiver for receiving a combination signal having two separate signal portions whose pulses are shifted relative to each other and/or whose carrier waves have a phase difference is configured to obtain a first series of samples using a first sampling, which is adjusted to a symbol phase of the first signal portion, and to obtain a second series of samples using a second sampling, which is adjusted to a symbol phase of the second signal portion, to obtain probabilities of transmission symbols of the first signal portion and probabilities of transmission symbols of the second signal portion for a plurality of sampling times based on the second and first series of samples, to determine probabilities for symbols of the second signal portion based on samples of the first sampling and estimated or calculated probabilities for symbols of the first signal portion, taking into account inter-symbol interference between transmission symbols of the second signal portion in the samples of the first sampling, and probabilities for symbols of the first signal portion based on samples of the second sampling and estimated or calculated probabilities for symbols of the second signal portion, taking into account inter-symbol interference between transmission symbols of the first signal portion in the samples of the second sampling.

Disclosed is a precoding method for generating, from a plurality of baseband signals, a plurality of precoded signals that are transmitted in the same frequency bandwidth at the same time. According to the precoding method, one matrix is selected from among matrices defining a precoding process that is performed on the plurality of baseband signals by hopping between the matrices. A first baseband signal and a second baseband signal relating to a first coded block and a second coded block generated by using a predetermined error correction block coding scheme satisfy a given condition.

All data symbols used in data transmission of a modulated signal are precoded by hopping between precoding matrices so that the precoding matrix used to precode each data symbol and the precoding matrices used to precode data symbols that are adjacent to the data symbol in the frequency domain and the time domain all differ. A modulated signal with such data symbols arranged therein is transmitted.