Blind adaptive multiuser detection based on affine projection algorithm

In this letter, we introduce a novel blind multiuser detector based on the affine projection algorithm (APA) for direct-sequence code-division multiple-access (DS-CDMA) systems. Computational complexities of least mean-squares (LMS), recursive least squares (RLS), Kalman, and APA-based blind multiuser detection algorithms are compared. The proposed technique has similar convergence and tracking properties as the RLS algorithm with much reduced computational cost. Simulation results are presented to compare our APA-based algorithm with the blind LMS, RLS, and Kalman schemes.