Patent ID: 8588322

Claim:
A device, comprising: a module for detecting and generating bit soft-output information of transmit sequences of digitally modulated transmit symbols taken from an input discrete set, said transmit symbols being transmitted by T multiple transmitting antennas and received by R multiple receiving antennas, whereby said multiple transmitting antennas and said multiple receiving antennas jointly define an equivalent transmission channel modelled by a channel estimate matrix and said received symbols are grouped as an equivalent received vector, which can include symbols transmitted and received in multiple time instants, as well as the related channel estimates coefficients, and wherein the device further includes a number of sub-units, including: a channel estimate pre-processing unit which computes T linear transformations of the type R j =A j H j , j=1, . . . , T of as many column-wise re-ordered versions (H j ) of said channel estimate matrix H, where A j is a matrix converting H j in a triangular matrix R j , wherein the ordering of the columns of H j corresponds to an ordering of the transmit symbols in the sequence X j , and where each ordering differs from the other for the index value in the last position, considered as “reference layer”, so that all T layers become in turn the reference layer in one sequence X j once and only once; a received vector processing unit which generates T processed received vectors using the results of said channel estimate pre-processing unit and namely computes Y j ′=A j Y, j=1, . . . , T; a demodulation and soft-output generation unit that performs at least the following steps, to be repeated for j=1, . . . , T: determining a set of candidate transmitted sequences {circumflex over (x)} j , each an estimate of X j , obtained by a group partitioning where: a set of candidate symbols of the reference layer is first selected according to a given strategy; for each candidate symbol of the reference layer, the remaining symbol estimates are derived recursively starting from the candidate symbol; computing the Euclidean Distance terms T ED =∥Y′ j −R j {circumflex over (X)} j ∥ 2 for each {circumflex over (x)} j of said set of candidate transmitted sequences, wherein ∥ ∥ 2 denotes the | 2 -norm of the argument; computing the bit soft output information of the bits corresponding to the symbol transmitted by the j-th transmit antenna.