Adaptive blind interference cancellation in CDMA systems

Multiuser CDMA communication systems experience multiple access interference as well as multipath distortions and require some interference cancellation scheme at the receiver. While blind multiuser receivers have received considerable attention, adaptive versions are often limited to the no multipath case. In this paper, the receiver's output variance is minimized subject to appropriate constraints which take into account the multipath channel of the user of interest. The constraint parameters are also jointly optimized resulting in a min/max problem. Adaptive solutions are proposed based on gradient descent and recursive least squares procedures. It is shown that the proposed method enjoys global convergence and its performance Is close to the trained MMSE receiver.