Orthogonal array optimization method for multiuser detection in DS-CDMA systems

Due to the high computational cost of the maximum likelihood detector, most existing works have investigated simplified, linearized, and/or sub-optimal solutions that have fewer computational requirements. In our approach, we use the Taguchi method that involves the use of orthogonal arrays in estimating the gradient of the likelihood function. In this work, we choose the likelihood function as the cost function in the Taguchi method. The Taguchi method leads to efficient algorithms that can find a satisfactory solution by maximizing the likelihood function in a small number of iterations. Simulation results show that the Taguchi multiuser detector significantly outperforms the conventional receivers, is insensitive to initial values of parameters, and has performance close to that of MMSE detectors and decorrelating detectors. In addition, our algorithm is suitable for parallel implementations.