Performance analysis of handoff schemes with preemptive and nonpreemptive channel borrowing in integrated wireless cellular networks

In this paper, we propose and analyze two different handoff schemes in integrated wireless mobile networks. The channels in each cell are divided into two parts and pre-allocated for real-time and nonreal-time services. To increase the channel utilization while keeping the quality of service (QoS) of each type for traffic, one type of service is allowed to borrow channels from the other under certain constraints. Depending on whether or not nonreal-time service calls can be interrupted, we have two channel borrowing schemes: nonpreemptive and preemptive. We use a system model defined by a multidimensional Markov chain and compute the performance in terms of blocking probability of originating calls, forced termination probability of real-time service calls, and average transmission delay of nonreal-time service calls. The simulation results are observed to match closely with the analytical model. The preemptive borrowing scheme is observed to perform better than the nonpreemptive scheme at the cost of increased handoff for nonreal-time service calls. The impact of the long-term dependence of data traffic on system performance is also discussed.