Apparatus and method for symbol detection are disclosed. The solution comprises obtaining (400) multiple-input-multiple-output symbols received over a transmission channel, the symbols comprising a plurality of layers, each layer comprising a constellation point of multiple candidate constellation points, selecting (402) for each layer a precision, each layer having a precision smaller or equal than the precision of a previous layer and searching (404) for each layer, utilising the selected precision, the constellation point among the candidate constellation points by minimising a given cost function, utilising a plurality of Arithmetic and Logic Units, ALUs, comprising at least one real and imaginary part, the ALUs of the apparatus comprising real and imaginary part having different precisions by having different number of bits, the data memory and the plurality of ALUs being connected with each other by a data bus of a given width.

A receiver for receiving a signal including a plurality of symbols through a multiple input multiple output (MIMO) channel, and an operation method of the receiver are provided. The receiver includes a demodulator configured to calculate, for each physical channel, Euclidean distances of one or more of the received symbols with respect to all candidate vectors included in an initial candidate vector set and to output information about the Euclidean distances. A vector set detector may select, based on the information, one of a plurality of candidate vector sets having different sizes, as a subsequent candidate vector set for calculating a log likelihood ratio (LLR) of other symbols of the plurality of symbols or an LLR with respect to a second signal received following the first signal.

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.

Apparatus and method for symbol detection are disclosed. The solution comprises obtaining (400) multiple-input-multiple-output symbols received over a transmission channel, the symbols comprising a plurality of layers, each layer comprising a constellation point of multiple candidate constellation points, selecting (402) for each layer a precision, each layer having a precision smaller or equal than the precision of a previous layer and searching (404) for each layer, utilising the selected precision, the constellation point among the candidate constellation points by minimising a given cost function, utilising a plurality of Arithmetic and Logic Units, ALUs, comprising at least one real and imaginary part, the ALUs of the apparatus comprising real and imaginary part having different precisions by having different number of bits, the data memory and the plurality of ALUs being connected with each other by a data bus of a given width.

The invention relates to an apparatus for selecting candidates in a K-Best algorithm of a MIMO decoder. The K-Best algorithm uses a layered structure comprising a first layer and subsequent layers. In each subsequent layer 2.sup.L candidates are selected by iteratively carrying out a selection step, wherein in the selection step the apparatus is configured to calculate and select at least two candidates having minimum distance values of a candidate group, and after each iteratively carried out selection step, the selected at least two candidates are sent to a further subsequent layer for iteratively generating a further candidate group of 2.sup.L candidates in the further subsequent layer.

There is provided a decoder for decoding a data signal received through a transmission channel in a communication system, the decoder (310) comprising a symbol estimation unit (311) configured to determine estimated symbols representative of the transmitted symbols carried by the received signal, the estimated symbols being determined from nodes of a decoding tree based on a weight metric associated with each of the node. The decoder further comprises a termination alarm monitoring unit (312) for monitoring a termination alarm depending on the current decoding computation complexity, the termination alarm being associated with a metric parameter, the symbol estimation unit being configured to reduce the weight metric of each node of the decoding tree by a quantity corresponding to a function of the metric parameter associated with the termination alarm, in response to the triggering of the termination alarm.

A method of detecting a symbol transmitted over a communication channel in a multiple input-multiple output communication system. The method includes receiving a plurality of symbols transmitted over a communication channel of a multiple input-multiple output communication system. A sphere radius is initialized based on attributes of the communication channel. A first matrix of possible transmitted signals is defined as well as a second matrix of received symbols. The matrix of possible transmitted signals is searched using a breadth-first search (BFS). Each level of the search tree is analyzed utilizing matrix multiplication to determine selected symbols satisfying the initialized sphere radius. A maximum likelihood solution is of the transmitted symbols is derived based on the selected symbols.

A method of detecting u symbol transmitted over a communication channel in a multiple input-multiple output communication system. The method includes receiving a plurality of symbols transmitted over a communication channel of a multiple input-multiple output communication system. A sphere radius is initialized based on attributes of the communication channel. A first matrix of possible transmitted signals is defined as well as a second matrix of received symbols. The matrix of possible transmitted signals is searched using a breadth-first search (BFS). Each level of the search tree is analyzed utilizing matrix multiplication to determine selected symbols satisfying the initialized sphere radius. A maximum likelihood solution is of the transmitted symbols is derived based on the selected symbols.

A device for determining a received signal as minimum values of a set of values, the device comprising a processor configured to: load a first set of values in a register; identify a maximum value of the first set of values and a minimum value of the first set of values; in the register, replace the maximum value by a value of a second set of values and simultaneously replace the minimum value by a new value, calculated based on the minimum value, to receive an updated first set of values; and repeat previous steps until all values of the updated first set of values are replaced by values of the second set of values.

A method, device, and a computer program are provided to decode a signal received through a transmission channel in a communication system, the received signal being represented by a signal vector. The method comprises: calculating an initial estimate of a transmitted symbol vector carried by the received signal vector; calculating a bound parameter (201) from a linear function of the initial estimate of the transmitted symbol vector, the linear function being defined by a slope coefficient and an intercept coefficient, the method further comprising: determining estimated symbols representative of the transmitted symbols carried by the received signal, the estimated symbols being determined from a set of candidate lattice points, each lattice point comprising a set of components, each component of a candidate lattice point being searched in a search interval (203), the search interval having at least one search interval bound computed from the bound parameter; determining (205) the estimated symbols from the closest lattice point to the received signal vector among the candidate lattice points.