Simulating macrocell-microcell handovers in 4G systems

Fourth Generation (4G) systems are expected to operate the global mobile network coverage area. They provide various services for different user types and their requirements. Vertical handovers occur between two layers of cells when a user is switched from one layer to the other. This paper details the influence of network parameters on vertical handover performance in a cell by simulating an overlapped macrocell-microcell environment. It considers handover requests entering a macrocell from a neighbor macrocell and from microcells of a different layer. We calculate various network performance parameters such as mean queue delay, handover dropping probability and channel utilization and compare the handover performance for macrocell and macrocell traffic. Our results demonstrate the influence of total channels, maximum queue size and handover request arrival rate on handover performance. They also show that the performance of each layer is similar in the case were the traffic from each layer is treated with equal priority in the system.