Efficient packetised CDMA system for a high mobility urban environment

A CDMA system for a high mobility environment is considered. The radio channel examined is a multipath Rayleigh fading channel with intersymbol interference (ISI) applicable to a heavily built up urban environment. In such environments, the maximum number of simultaneous users is seriously limited by the hostile propagation conditions and the rapidly changing multiple access interference (MAI) from other users. This paper examines a practical implementation of an improved LMS-LMMSE receiver for wideband CDMA systems operating over a fast fading channel. The numerical results with very short spreading sequences demonstrate that the modified adaptive algorithm improves the performance of the adaptive LMMSE receiver remarkably in fading channels. The performance is compared to that of a standard LMS receiver