Adaptive Multiuser Decision Feedback Demodulation for GSM

Demodulation of multiple users in a cellular TDMA system with large power imbalance among the received signals and limited side information is considered. Our approach is to combine an adaptive multiuser decision-feedback demodulator (DFD) with multiple antennas. The DFD contains (matrix) nite-impulse response feedfor-ward and and feedback lters to mitigate both intersymbol and multiple-access interference. The MMSE lter coeecients are speciied, and adaptive estimation algorithms are presented which rely on training data from each user. Simulation results show that by cancelling a relatively strong user, the DFD ooers a signiicant improvement in performance for weak users relative to the linear MMSE receiver.