A Wideband BSOR-GSIC Multiuser Detector for Long-Code CDMA Systems

In this work, a new wideband linear group-wise SIC (GSIC) multi-user scheme that is asymptotically equivalent to the block successive over-relaxation (BSOR) iteration, which is known to outperform the conventional block Gauss-Seidel iteration by an order of magnitude in terms of convergence speed, is proposed. The proposed scheme uses directly the spreading codes and doesn´t require the calculation of the cross-correlation matrix which results in a considerable reduction in computational complexity. Hence it is suitable for long-code CDMA systems such as IS-95 and UMTS where the cross-correlation matrix is changing every symbol. We determine the condition of convergence of the proposed scheme and prove that it converges to the decorrelator detector if the over-relaxation factor is within the interval (0, 2). Simulation results are in excellent agreement with theory.