Decision feedback with rollout for multiuser detection in synchronous CDMA

Decision feedback (DF) is one of the most popular methods in multiuser detection due to its simplicity and outstanding performance. Despite the efficiency of the DF detector, there is usually a large performance gap between the DF detector and the optimal maximum likelihood detector. Rollout, an emerging technique from planning and optimisation, is employed to improve the performance of the decorrelator-based DF detector for synchronous code division multiple access channels. Simulation results show that the proposed algorithm significantly improves the joint error rate of the DF detector, and even outperforms the sequential group decision feedback detector for similar time complexities. Further, owing to the inherent parallel structure of the proposed algorithm, the method is particularly useful in applications where speed and accuracy are both important.