Patent ID: 7230973
Filing Date: 2007-06-12
Classification: H04B,H04L

Abstract:
1. A method for detecting a plurality of symbols transmitted by or for a plurality K of users, each symbol belonging to a modulation constellation, comprising: filtering a received signal for supplying an observation vector (z) each component of which being related to a user; searching the closest neighbor of said observation vector among candidate vectors belonging to a subset, determined by said modulation constellations, of a lattice of points generated by a plurality of generating vectors, the search being limited to a volume centered around said observation vector and being carried out by sequentially selecting a coordinate of a candidate vector for each dimension of said lattice of points; expressing the components of said observation vector in a reordered lattice of points obtained by reordering said generating vectors according to an ordering rule prior to said search, the ordering rule being chosen so as to eliminate a higher rate of candidate vectors for a first dimension of the reordered lattice of points than for a subsequent dimension of the reordered lattice of points to be searched; and detecting the plurality of symbols transmitted by or for the plurality of K users by selecting a candidate vector closest to the observation vector, the selecting including expressing reordered dimensions as a permutation π of the rows of the generating vectors, once the closest point b of a constellation to a lattice point ρ has been found, an inverse permutation π