Blind Adaptive Multiuser Detection and Integrated Channel Estimation in Multipath CDMA Channels

Abstract- In this paper a blind, adaptive multiuser receiver for CDMA channels with integrated channel estimation is considered. The proposed receiver requires only the signature code of the user of interest (UOI) and does not require any training sequences, the channel parameters and signature codes of the interfering users. In a dynamic channel scenario, the tracking of the channel is done adaptively with reduced computational complexity. Though the channel parameters of the UOI are not explicitly calculated, the energies of multiple paths are advantageously combined as done in a conventional RAKE receiver. After removing the multiple access interference (MAI), the signal to noise ratio (SNR) of the system is further improved using the min-max criterion. The performance of the receiver matches that of a non-adaptive, non-blind MMSE receiver and its performance in a mobile, fading environment is found to be encouraging. In a high SNR scenario, no up-dation of the receiver filter is needed when the channels of the interfering users change and only a few computations are required for the up-dation of the receiver filter when channel of the UOI changes. Key-Words-Blind adaptive multiuser detection, integrated detection and channel estimation, min-max criterion, fading channels, MOE criterion, LMS algorithm