Patent ID: 8270506

Claim:
A method for signal decoding in a 2×2 Multiple-Input Multiple-Output (MIMO) antenna system, the method comprising: receiving one or more symbols; and decoding the received symbols at least partially by determining a nearest point in a lattice corresponding to at least a subset of a modulation map used in symbol transmission, wherein in realizing the decoding operation, the decoding utilizes an algorithm for reducing a basis in the complex space of the lattice, thus determining approximately an orthogonal new basis for the lattice, wherein the decoding comprises performing a calculation of soft bit decisions by enumerating several candidates at every layer, and wherein the enumerating of the several candidates is determined via a preorder tree search realized in the 2×2 MIMO as a search in all possible permutation matrices with a delimitation set by a transformation between the original lattice and the reduced basis lattice, each matrix of permutation between lattices being complex-valued integer-valued, and with assigning probabilities to the candidates using a conditional probability function.