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

This work proposes a new multiuser detector for DS/CDMA systems constituted by the polynomial Minimum Mean-Squared Error MMSE detector followed by a local search algorithm 1-adapt LS one-adaptive local search, namely the hybrid 1-adapt-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 Gerschgorin 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 analysed 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 Minimisation-Based Detector MMSE-MuD.