Blind adaptive multiuser detection using a vector constant-modulus approach

A vector constant-modulus (VCM) criterion based space-time blind adaptive detector that utilizes spatial diversity provided by an antenna array to suppress multiple-access-interference in direct-sequence code-division multiple-access (DS-CDMA) systems is proposed. The proposed detector is characterized in terms of the solution of a constrained optimization problem whose objective function is formed based on the VCM criterion. Our simulation results show that the demodulation performance of the proposed detector is close to that of several existing space-time detectors such as the constrained minimum-output-energy and the constant-modulus based detectors. However, the number of coefficients involved in the proposed adaptive detector is reduced significantly and, therefore, the convergence rate is increased.