Joint equalization and interference suppression for high data rate wireless systems

Enhanced Data Rates for Global Evolution (EDGE) is currently being standard ized as an evolution of GSM in Europe and of IS-136 in the United States as an air interface for high speed data services for third generation mobile systems. In this paper, we study space-time processing for EDGE to provide interference suppression. We consider the use of two receive antennas and p ropose a joint equalization and diversity receiver. This receiver uses feed forward filters on each diversity branch to perform minimum mean-square err or cochannel interference suppression, while leaving the intersymbol interf erence to be mitigated by the subsequent equalizer. The equalizer is a dela yed decision feedback sequence estimator, consisting of a reduced-state Vit erbi processor and a feedback filter. The equalizer provides soft output to the channel decoder after deinterleaving. We describe a novel weight gener ation algorithm and present simulation results on the link performance of E DGE with interference suppression. These results show a significant improve ment in the signal-to-interference ratio (SIR) performance due to both dive rsity (against fading) and interference suppression. At a 10% block error r ate, the proposed receiver provides a 20 dB improvement in SIR for both the typical urban and hilly terrain profiles.