A novel fuzzy logic based vertical handoff decision algorithm for heterogeneous wireless networks

The next generation wireless communication systems will combine multiple wireless access networks, thus can provide mobile users with the best services. In these heterogeneous wireless networks, vertical handoff decision plays an important role to guarantee Always Best Connected (ABC) services and seamless mobility for mobile terminals. In this paper, we first introduce a speed-adaptive system discovery scheme before vertical handoff decision, which effectively improves the update rate of the candidate networks set. Then we propose a vertical handoff decision algorithm based on fuzzy logic with a pre-handoff decision method. Compared with the traditional RSS based handoff algorithm and sole fuzzy logic based handoff algorithm, the simulation results show that the proposed algorithm's performance is enhanced by reducing unnecessary handoffs, balancing the whole network resources and decreasing the probability of call blocking and dropping.