Adaptive H∞-subweight equalizer for DS-CDMA communication system in time-varying multipath channels

In order to overcome the MAI and ISI problems in time-varying multipath fading channels, a novel H_∞-subweight algorithm for the decision feedback equalizer (DFE) in a DS-CDMA system is presented. The subweight technique can reduce the computational load of the H_∞ algorithm, but dynamic estimation error in subweight partition may degrade performance. The advantage of insensitivity to modeling error of the H_∞ algorithm just can mitigate the degradation of the subweight technique. Therefore, the individual advantages of the H_∞ algorithm and subweight technique can be successfully integrated. The H_∞ -subweight algorithm owns the advantages of low complexity and robustness against modeling error caused by the time-varying multipath channels as well as subweight partition. On the other hand, the RLS-subweight algorithm seriously suffers from the drawback of dynamic estimation error. The reduction of computational complexity by subweight partition is analyzed. Simulation results show that the H_∞ -subweight DPE outperforms the RLS-subweight DFE in suppressing equalization error