Performance/complexity issues in multi-user CDMA systems

Joint detection of synchronous and asynchronous CDMA is considered. A near-optimal detector structure is presented which consists of a linear preprocessor, a whitening matched matrix filter, followed by a reduced-complexity tree search, the M-algorithm. It is shown that this combination achieves a performance which is virtually identical to that of the optimal receiver, even for large numbers of users. The complexity of this detector is linear in the number of users K.