Adaptive space-time equalization for mobile receivers

We study the utilization of adaptive space-time (ST) signal processing for mobile receivers in frequency-selective cellular radio channels with cochannel interference and correlated fading. First, we introduce a bad urban spatio-temporal channel model for the perspective of a mobile multiple antenna receiver, present mobile array structures and inter-element correlations, and investigate cochannel interference conditions. We then conduct a comparative study for two promising combiner-equalizer structures, viz. a temporal decision-feedback equalizer (DFE) with a preselection diversity switch and a ST-DFE, all using recursive least squares (RLS) adaptation. Our results indicate that both techniques yield performance gains with respect to a single antenna receiver, with the more expensive joint space-time method often strongly superior to other setups. Finally, we present an efficient and stable structure for implementing the ST-DFE, using a QR-decomposition type of RLS adaptation