A VCM approach to multiuser detection for DS-CDMA frequency-selective fading channels

A new multiuser detector for direct-sequence code-division multiple-access (DS-CDMA) systems is proposed. In this detector, the detection is carried out by solving a linear-constrained optimization problem where the objective function is formulated based on the vector constant modulus (VCM) criterion. Two adaptation algorithms are developed for solving the optimization problem and computer simulations are conducted to evaluate the performance of the VCM detector. It is shown that this detector can effectively suppress multi-access interference (MAI) and intersymbol interference (ISI) present in the received signal. More importantly, the VCM detector offers robust detection performance against discrete-time signature distortion caused by aliasing at the receiver.