A modified constrained constant modulus approach to blind adaptive multiuser detection

An alternative blind adaptive multiuser detection is investigated based on modified constrained constant modulus (CM) criterion. It has been shown tha t the performance of a CM-based receiver is limited by the received power o f the desired user. In this paper, we show that the limitation can be avoid ed using noncanonical constraint CIM criterion and that in the presence of channel noise the modified CM criterion function is strictly convex by prop erly selecting some constant. With analyzing the extrema of the cost functi on, we point out how to select the constant. Moreover, a simple stochastic gradient algorithm for implementing our scheme is presented, and the conver gence properties of the algorithm are analyzed. Simulation examples are giv en to demonstrate the performance of the proposed scheme.