Adaptive space-time DFE (AST-DFE) receiver for GSM/DCS-1800 mobile communication system with spatial diversity

We consider using smart antenna array technique for GSM/DCS-1800 mobile communication system to combat fast dispersive fading channel and cochannel interference (CCI). By exploiting Laurent's (1986) AMP (amplitude modulation pulse) representation for GMSK signal, we first construct a linearized SI4O (single-input and four-output) model for a single-antenna GMSK receiver in terms of the de-rotation operation and T/2 fractionally sampling. With this linear model and spatial diversity, we then develop a so-called adaptive space-time decision-feedback-equalizer (AST-DFE) receiver, which is much simpler than the MLSE-based receiver. Adapted by the RLS algorithm, this receiver can cope with time-varying channels with high fading rate. Besides, to increase the capacity of GSM system, the receiver can be easily upgraded to multiuser detection operation. With computer simulations, we investigate the above AST-DFE receivers under different GSM channel models. It is demonstrated that by using the antenna array for reception, the space-time processing techniques can significantly improve the system performance as well as system capacity, as compared to the receiver with only a single antenna.