New sub-optimal multiuser detectors for synchronous CDMA systems

In synchronous CDMA systems, the optimal multiuser detection is equivalent to an unconstrained quadratic bivalent optimization problem. This detector has an exponential computational complexity with the number of users which makes it impractical. We propose several sub-optimal detectors based on a local minimization algorithm. The performance of these detectors are compared with those of the optimal and several other sub-optimal solutions. It is shown that the optimal performance is closely approached by one of our solutions with greatly reduced computational complexity