In a communications device operating with a blind signal separation (BSS) processor, an initial mixing matrix is formed based upon the different summations of the source signals received by the antenna array. The initial mixing matrix is evaluated to determine a minimum rank that is necessary for at least one source signal to be useable after having been separated from the initial mixing matrix and decoded. An additional mixing matrix is then formed, and also includes the different summations of the source signals. If the rank of the additional mixing matrix is less than the minimum rank associated with the initial mixing matrix, then the source signals are modified so that the rank of the additional mixing matrix is increased.