Multi-criteria vertical handoff decision algorithm for overlaid heterogeneous mobile IP networks

Abstract

One of the key challenges to improving the quality of service (QoS) in integrated heterogeneous mobile Internet protocol networks is the design of an intelligent decision engine for accessing various services anywhere and at any time. The multi-criteria decision making algorithm plays a significant role in ensuring universal and seamless connection. In this study, a multi-criteria vertical handoff decision algorithm plus dwell time is developed to achieve a satisfactory quality of service using the best access network selection in an integrated wireless local area network (WLAN), a worldwide interoperability for microwave access (WiMAX), and a universal mobile telecommunications system (UMTS). Handoffs are divided into two schemes: the UMTS originating handoff (downward) and the WLAN/WiMAX originating handoff (upward/intrasystem). The initial criteria for real-time and non-real-time services are presented. The metrics that are required to trigger a handoff are the predictive received signal strength (PRSS) of neighbor networks and the received signal strength obtained from the current network. The back propagation neural network is learned for the prediction. The dwell time is used as a counter to avoid the unnecessary handoffs that may occur in the overlapping areas. The quantitative network selection is the largest merit value and is based on the available bandwidth, cost, user preference, and the criteria to eliminate inappropriate candidate networks. The importance of using the PRSS, dwell time, and merit function is evaluated. To illustrate the QoS satisfaction, the multi-criteria vertical handoff decision algorithm outperforms the single-criteria using the hysteresis and Mamdani fuzzy method.