Hybrid local search polynomial-expanded linear multiuser detector for DS/CDMA systems

This work proposed a new multiuser detector for DS/CDMA systems constituted by the polynomial MMSE detector followed by a local search algorithm 1-adapt LS (one-adaptive local search), namely the Hybrid 1adapt-LS-MuD. In order to reduce computational complexity inherent to recurrent computation of the cross-correlation matrix inverse in DS/CDMA multiuser detection (MuD), this work introduces for the first time a hybrid multiuser detector based on polynomial expansion (PE-MuD) with α-estimation aided by Gesrchgorin circles (GC), followed by a low complexity local search procedure, aiming at obtaining a near-optimum multiuser bit-error-rate (BER) performance, but with a considerable saving in computational complexity. The proposed hybrid PE-MuD receiver topology is analyzed under realistic wireless mobile channels, as well as useful system operation scenarios. Numerical results obtained via Monte-Carlo simulations (MCS) have indicated a remarkable improvement in performance-complexity trade-off regarding the classical linear multiuser detectors (LMuD) performance, particularly, the mean square error minimization-based detector (MMSE-MuD).