Queueing for handover calls in a hierarchical cellular network

In this work, the performance of queues for handover calls in both a micro- and a macrocell is analysed by varying the number of microcells under a macrocell, arrival rates of new calls in micro- and macrocells, cell dwell times, signal degradation interval, and queue size of both micro- and macrocells. In the model, the role of a macrocell is as a secondary server for handover calls overflowed from microcells and the overflow process of handover calls from microcells is modelled by Poisson and Markov modulated Poisson process (MMPP) approximations. In the numerical examples, it is found that Poisson approximation optimistically estimates call performance compared to MMPP, and that queues in a macrocell are more effective than those in microcells.