Outage-based fuzzy call admission controller with multiuser detection for WCDMA systems

Abstract

An outage-based fuzzy call admission controller with multiuser detection (OFCAC–MUD) is proposed for wideband code division multiple access (WCDMA) systems. The OFCAC–MUD determines the new call admission based on the uplink signal-to-interference ratios from home and adjacent cells and system outage probabilities. The OFCAC–MUD possesses both the effective reasoning capability of a fuzzy logic system and the aggressive processing ability of MUD. Simulation results reveal that OFCAC–MUD without power control (PC) improves the system capacity by 70.5% as compared to an SIR-based CAC–RAKE with perfect PC. It also enhances the system capacity by 53.9% as compared to an OFCAC–RAKE with perfect PC, by 6.7% as compared to an SIR-based CAC–MUD without PC and by 12.9% as compared to an OFCAC–MUD with perfect PC, given the same outage probability requirements. Moreover, OFCAC–MUD can prevent the violation of outage probability requirements in the hotspot environment, which is hardly achieved by SIR-based CAC.