Adaptive Soft Handover Algorithm for UMTS Systems

The unbalanced traffic load in the cellular Code Division Multiple Access (CDMA) system occurs frequently, and it may lead to system performance deterioration. In this paper, new soft handover (SHO) algorithm with adaptive handover thresholds is proposed to resolve this problem. The basic objective of the adaptive algorithm is to modify the coverage among the serving cells based on the load distribution, and consequently attain the traffic load balancing in the service regions. According to the simulation results, the proposed algorithm can balance the traffic load and has better overall performance compared with the Universal Mobile Telecommunication System (UMTS) SHO algorithm with fixed handover thresholds. In particular, the new adaptive algorithm can be implemented in the UMTS system without any alteration.