A signal vector is received over a plurality of channels. A channel matrix H is determined that represents at least one of the plurality of channels. An iterative algorithm such as Lenstra-Lenstra-Lovasz is used to determining a change of basis matrix T that when multiplied with the channel matrix H converges to a matrix H*T that is more orthogonal than the channel matrix H. In one aspect the iterative algorithm is upwardly bounded in the number of iterations (e.g., 20 or 30 iterations) that it may perform for any specific channel realization to determine the change of basis matrix T. In another aspect the algorithm is initiated with a matrix derived from a previously determined change of basis matrix. Both aspects may be combined in a single method or device, or either employed separately.