Performance of a Blind Adaptive Digital Beamformer on a Multi-user Rician Channel

In this work we test the performance of a blind adaptive digital beamformer for multiple users transmitting to a base station that is equipped with a uniform linear array (ULA) antenna. Each user transmits a signal block of complex QAM signals over a wireless channel, with multipath fading and noise. This channel is modeled by a Rician distribution with a dominant line-of-sight (LOS) path and three non-LOS (NLOS) paths. The beamformer is implemented using a blind adaptive CMA-AMA cost function to recover the signal block from each user, and to estimate the channel in a multi-stage manner. The performance of the system is evaluated over a range of transmitted signal power from the users. We evaluate the effect of varying the number of elements at the base station ULA antenna, by comparing symbol error rates (SER) of the received signal and the mean square error (MSE) of the estimated channel.