multiuser detection using backpropagation networks for cdma systems
Multiuser detection paradigm gives efficient techniques for separation of users in CDMA system specially, when the system has a high MAI due to the non-orthogonality of the used codes. Many techniques are presented for multiuser detection but most of them are static, i.e. assuming time-invariant channel which is not the practical case. Some of the presented techniques are dynamic but their transfer function is linear which doesn't give the optimum or near optimum BER as required. This paper presents a dynamic multiuser detection technique based upon backpropagation neural networks using sigmoid transfer function. Simulation is performed to compare the proposed technique with other neural networks techniques and other static techniques. The simulation results show that the proposal causes BER enhancement over the considered techniques.
multiuser detection backpropagation networks cdma time-invariant channel neural networks