A Novel Vertical Handoff Algorithm for UMTS and WiMAX Heterogeneous Overlay Networks

Next generation mobile communication is developing towards heterogeneous overlay networks, which provide multiple access patterns for users. Efficient vertical handoff algorithms among different network are required to meet a user's quality of service. In this paper, a vertical handoff algorithm is proposed in which fuzzy logic processing (FLP) is combined with analytic hierarchy process (AHP) for UMTS and WiMAX overlay networks. In its FLP section, dynamic network parameters including received signal strength (RSS) and available bandwidth (BA) are exploited to evaluate the user satisfaction (US) by fuzzy inference. In its AHP section, a decision matrix is constructed using the parameters of service cost, battery consumption, network delay and user preference. Finally, the decision is made according to the weighted value of US and AHP for different traffic type. Simulation results show that the approach can effectively mitigate ping-pong effect as well as terminal power consumption.