Fast optimal and suboptimal any-time algorithms for CWMA multiuser detection

A fast optimal algorithm based on the branch and bound method, coupled with an iterative lower bound update, is proposed for the joint detection of binary symbols of K users in a synchronous correlated waveform multiple-access (CWMA) channel with Gaussian noise. The proposed method significantly decreases the average computational cost and the decision feedback detector (DFD) is proved to be a first order approximation to the optimal algorithm. Furthermore, a suboptimal algorithm using the probabilistic data association (PDA) is also proposed. It is shown that the suboptimal algorithm gives a near-optimal performance at a computational cost of O(K³)