Adaptive MMSE receivers for communications in non-stationary multipath fading channel

This paper deals with two adaptive Minimum Mean Square Error (MMSE) receivers for Direct Sequence Code Division Multiple Access (DS/CDMA) wireless communication systems: in particular, the two different schemes, named as Post-combining and Precombining are considered with two adaptive algorithms, the Least Mean Squares (LMS) and the Recursive Least Squares (RLS). Proposed Adaptive MMSE receivers don't need knowledge of desired user's signature waveform, only requiring the use of Training Sequences (TS) at the start up, since decision directed mode is adopted after TS first transmission. Detectors performance is expressed in terms of Bit Error Rate (BER), which has been derived by simulations under the assumption of frequency-selective Rayleigh fading channel. Reported simulation results shown here highlight adaptive MMSE receivers good behaviour and remarkable near-far resistance, even in worst fading environments.