Model and Optimal Call Admission Policy in Cellular Mobile Networks

For current cellular networks, two important Quality of Service (QoS) measures are the fractions of new and handoff calls that are blocked due to unavailability of channels. Based on these QoS measures, we propose a queuing network model with impatient users for handoff and new calls in cellular mobile networks. The number of simultaneous calls, that can be supported, is modeled by C identical servers with exponentially distributed session duration for each one of them. Priority is given to handoffs over new calls. We use for that a Guard Channel policy that reserves a set of CH channels for handoff calls, new calls being served at their arrival if there are more than CH available channels. We derive loss probabilities, mean waiting times in the queues, and we show that the Guard Channel policy is optimal for minimizing a linear objective function of the new and handoff calls. Simulation results illustrating the behavior of our system are given.