Constrained minimum-BER multiuser detection

A new linear multiuser detector for binary signaling in code-division multiple-access communication systems is described. The new detector directly minimizes the bit-error rate (BER) subject to a set of reasonable constraints. It is shown that any local minimum of the constrained BER cost function is a global minimum; hence a robust constrained minimization algorithm always leads to a detector with good performance. Although the proposed detector cannot be shown to be optimal among linear multiuser detectors because of the constraints imposed, our analysis and simulations indicate that it always outperforms the decorrelating detector and is optimal for most realistic systems.