An effective prioritization scheme for handovers in cellular networks

The authors present a method of improving the quality of service in cellular systems based on prioritization of handover requests. Handover prioritization schemes lead to a tradeoff between the improvement of the probability of successful handover and spectrum utilization. The objective is to improve perceived quality of cellular service by minimizing both the probability of forced termination of ongoing calls due to handover failures and the degradation in spectrum utilization. The authors present a handover policy based on a multiple priority nonpreemptive queueing of calls in progress. Originating calls are blocked if all channels are occupied. Handover requests are queued such that as soon as a channel is available, it is offered to the mobile subscriber with the measurement results closest to the minimum acceptable power level for communication. The queue is dynamically reordered as new measurement results are submitted. The results of the authors´ simulation study show that the new scheme provides lower probability of forced termination, less call blocking, less reduction in traffic and less delay than the single priority class FIFO queueing under all traffic conditions