SSOR preconditioned GPBiCG method for the linear interference cancellation of asynchronous CDMA systems

Abstract

The decorrelator or the linear minimum meansquared-error (LMMSE) detector has its computational complexity of O(K 3 ) where K is the number of users. On the other hand, the computational complexity of iterative detector algorithms such as conjugate gradient (CG) and generalized product bi-conjugate gradient (GPBiCG) methods only require the computational complexity O(K 2 ) per iteration. In this paper, the symmetric successive overrelaxation (SSOR) preconditioning scheme is applied to the GPBiCG method. The performance of the detectors is investigated and it is found that the SSOR preconditioned GPBiCG method can provide significantly faster convergence.