Performance analysis of preemptive handoff scheme for integrated wireless mobile networks

We propose and analyze a preemptive handoff scheme for an integrated real-time and non real-time service wireless mobile network. The total channels of each cell are divided into three parts, one is for real-time service calls only, the second is for non real-time service calls only, and the last one is for overflowed handoff requests that can not be served in the first two parts. Out of third part, a few channels are reserved exclusively for the real-time handoffs service. To give the real-time service handoff requests higher priority over non-real-time service handoff requests, the real-time service handoff request is allowed to preempt the non-real-time service call when it finds no channel available on its arrival. The interrupted non-real-time service call returns back to the non-real-time service handoff request queue. The system is modeled by a multi-dimensional Markov chain and a numerical analysis is presented to estimate blocking probabilities of originating calls, forced termination probability of real-time service handoff requests calls, and average transmission delay of non-real-time service calls. This scheme is also simulated using extensive runs and both results are observed to agree fairly well. It is seen that the forced termination probability of real-time service calls is significantly reduced with our scheme while the probability of packet loss of non-real-time transmission is made to be negligibly small, as a non- real-time service handoff request can be transferred from the queue of current base station to another one.