Load balancing based on traffic selection in heterogeneous overlapping cellular networks

For the sake of anywhere and anytime connectivity in the next generation networks, different wireless access networks are integrated to form a heterogeneous network and the mobile stations are multi-mode multi-interface. It is a very significant research to find out how to serve more mobile stations as many as possible and to increase the overall heterogeneous system utilization. In this paper, we propose a load balancing algorithm for the heterogeneous overlapping cellular networks to achieve the two goals. This load balancing algorithm is able to balance load among heterogeneous cells by instructing new calls to access to under-loaded cells and only selecting mobile stations with non-real time traffic in overloaded cells to handoff to under-loaded heterogeneous cells. Meanwhile, there are some measures to guarantee the QoS of vertical handoff calls selected. Simulation results show that blocking probability, dropping probability and overall system utilization are improved significantly at the cost of an increase of the total number of handoffs.