A Fuzzy Adaptive Soft Handover Scheme Supporting Four Active Sets

Load imbalance between cells caused by random user distribution is a common issue in cellular systems, which often leads to traffic congestion. This can be alleviated by embedding a load balancing strategy into the handover scheme to dynamically reallocate load between neighbouring cells. A fuzzy adaptive soft handover scheme that can support four active set size is presented in this paper. In this paper, three fuzzy systems for radio link: addition, removal and replacement events are used and tuned to adapt to the soft handover thresholds and time hysteresis efficiently, depending upon the loads of the cells in user's active set. Simulation results show that the new fuzzy algorithm alleviates congestion and provides improved system performance in terms of both lower blocking probabilities and higher system capacity