Constrained complexity spatio-temporal interference rejection combining

Space-time processing for co-channel interference (CCI) rejection and equalization with antenna arrays may provide large gains over space-only processing, especially in interference limited scenarios. However, taking the temporal correlation of the noise and CCI process into account leads to sequence detection with higher complexity as compared to space-only processing that neglects this correlation. We propose the use of the generalized Viterbi algorithm for sequence detection with lower complexity. Special cases include the M-algorithm and the delayed decision feedback sequence estimator. A relevant comparison between spatial and spatio-temporal processing with sequence detectors of the same complexity may thus be performed. Numerical examples show substantial gains for spatio-temporal processing as compared to space-only processing also in this case when the optimality of the sequence detector is traded for interference rejection.