Application of fuzzy logic for adaptive interference canceller in CDMA systems

In this paper, the performance of the proposed fuzzy logic parallel interference cancellation (FLPIC) multiuser detector is evaluated for frequency-selective fading channels in wireless CDMA communication systems. A modified fuzzy logic system (FLS) with an adequate scaling factor (SF) is proposed to infer adequate partial factors (PFs) for the PIC scheme. Simulation results show that the proposed FLS can adapt to the large variations of users' fading effects. Therefore, the FLPIC outperforms the conventional PIC (CPIC) and constant weight PIC (CWPIC) over two-path and three-path time-varying frequency-selective fading channels especially at heavy system load in DS-CDMA systems.