Grade of service balancing for originating and handoff calls and system cost minimization using genetic algorithm

With the increasing popularity of mobile wireless communication systems, customers are expecting the same quality of service (QoS), availability and performance from the wireless communication networks as the traditional wire-line networks. Currently the research work on radio channel allocation in cellular mobile systems focuses mainly on two aspects, improving the user admission capability and protecting the connection continuity for handoff calls as a QoS constraint. However, given a QoS constraint, a wireless network has to sacrifice its capacity in order to support an increase in handoff rate. In this paper, we propose and analyze a different handoff scheme which not only gives priority to handoff calls, due to importance of them from QoS standpoint, but also protects originating calls to keep system capacity at an acceptable level. We will describe the optimum design of our scheme to minimize the system cost. We use genetic algorithm (GA) to solve optimum design problem. To do so, a model of cost characteristics has been derived for the proposed scheme. Indeed, the robustness of our approach is that analytically minimizes the system cost. We use a system model defined by a two dimensional Markov chain which computes mathematically the performance in terms of the blocking probability of originating calls, forced termination probability and call incompletion probability. Results are compared with conventional guard channel (GC) scheme