Modeling handovers in cellular mobile networks with dynamic channel allocation

A model for a cellular mobile network is given which uses the dynamic channel allocation strategy proposed by Everitt and Macfadyen. In this model, handovers of calls from one cell to another are explicitly included. The equilibrium distribution of this network is shown to have product form under certain reversibility conditions. The conditions are restrictive and are, perhaps, unlikely to hold in practical models. However, their study does provide insight into the behavior of cellular systems with dynamic channel allocation. Using the product-form equilibrium distribution the authors are able to express the blocking probability for new calls, and the blocking probability for handover calls in terms of appropriate normalizing constants. The model is also extended to allow directed retry for handovers in which blocked handover attempts may try to gain access via another cell. This provides differential service for handovers. Again, some reversibility conditions ensure product form, and the blocking probabilities for both new and handover calls are given in terms of normalizing constants.