A Two-Stage Receiver for Co-channel Interference Cancellation in Space-Time Block-Coded Systems over Frequency Selective Channels

In this work we propose a new receiver structure for space-time block-coded systems that decouples the tasks of CCI cancellation and space-time decoding in two processing stages. The two-stage receiver consists of a multiple-input multiple-output (MIMO) minimum mean square error (MMSE) spatial filter for CCI cancellation connected to a modified time-reversal space-time decoder that is matched to the combined response of the channel of the desired user plus the MIMO-MMSE filter. A prefiltered MLSE detector is used for equalization. The two-stage receiver is compared to the one proposed in [10] for flat-fading channels. We show via computer simulation that the two-stage receiver effectively cancels CCI signals and still provides transmit diversity gain under frequency-selective fading.