A call admission control strategy based on fuzzy logic for WCDMA systems

Call admission control (CAC) plays a basic role in multimedia 3G systems, properly accommodating new connection requests while ensuring seamless service provision to the existing connections. CAC is classically based on signal to interference ratio estimates and threshold comparisons. A novel CAC strategy founded on fuzzy logic is proposed in this paper for WCDMA systems and, in particular, for UMTS. Starting from cell parameters like congestion state, available load and total interference a fuzzy set is defined. A fuzzy rule base is then constructed, giving the rules for the admission criterion. An UMTS radio access simulator, fully taking into account both user movement and channel conditions is employed to evaluate the performance of the new CAC algorithm and compare it to classic solutions. Simulation results show the improvements attained by the proposed solution.