A hybrid digital signal processing-neural network CDMA multiuser detection scheme

We present a new hybrid digital signal processing-neural network two-step multiuser detection scheme whose small computational complexity makes it attractive for real-time CDMA multiuser detection. An investigation on the nature of the local minima of the Optimal Multiuser Detector´s (OMD) objective function leads to the development of an efficient algorithmic stage that can reduce significantly the size of the OMD optimization problem. This stage may then be followed by a Hopfield neural network employed to solve a smaller size residual problem of the same form. The performance of the hybrid detector is evaluated via simulations and it is shown to exceed that of other suboptimal receivers at a much lower computational cost in both synchronous and asynchronous CDMA transmission cases