Iterative multiuser detection with parameter estimation

In this paper we present an iterative multiuser receiver for CDMA systems which performs joint parameter estimation and symbol detection on an additive white Gaussian noise channel. This receiver operates online and iteratively estimates the signal amplitude and noise variance using the available soft decision of the transmitted symbol. Simulation results show that the performance of this adaptive receiver is very close to that of the nonadaptive version; i.e., when the signal amplitude of all users is known. We also present graphical results of the convergence of the original iterative scheme (with no parameter estimation) for a system with no interchip interference.Van K. Nguyen and Langford B. Whit