Dynamic priority queueing of handover calls in wireless networks: an analytical framework

In this paper, we present an analytical framework for dynamic priority queueing of handover calls in wireless networks. The framework employs a queueing discipline with two classes of priority for handover calls. Two queues, first priority and second priority, are employed for the two priority classes of handover calls. The priority of queued handover calls is not based only on the received signal strength, but also on the remaining time in the overlap region between two cells. We also incorporate a priority transition between handover calls in the queue; specifically, a second-priority handover call in the second-priority queue, based on certain criteria, can become a first-priority handover call and join the first-priority handover queue. In addition, the event that a handover call could finish its call while waiting in the queue is taken into account in the analysis. This event was not taken into consideration in previous related studies and, as a result, these previous studies overestimate handover failure probability. Our results also show that the predictions of the analytical framework developed in this paper are in very good agreement with simulation results. The developed analytical framework is comprehensive and can also cope with several priority schemes proposed by other researchers in the literature. For example, it is shown that, under certain conditions, the proposed framework converges to first-in-first-out queueing of handover calls. One can easily modify the proposed framework to incorporate priority schemes that use guard channels for handover calls. It is also shown that one could potentially use the framework developed in this paper in integrated voice/data networks, as well as for handover between different network types. The proposed analytical framework is anticipated to be a very useful tool in evaluating performance of present and future wireless networks employing dynamic priority queueing for handovers and in designing more efficient handover algorithms.