An Improved Vertical Handoff Decision Algorithm for Heterogeneous Wireless Networks

One of the major design issues in heterogeneous wireless networks is the support of vertical handoff. Vertical handoff occurs when a user with a multi-interface terminal changes association from one type of wireless access technology to another while maintaining an active session. It is believed that vertical handoff decision will be based on multiple criteria. In this paper, new handoff criteria are introduced along with an improved vertical handoff decision strategy based on fuzzy logic. A performance study using the integration of cellular networks and WLANs as an example shows that our proposed vertical handoff decision algorithm can reduce the handoff call dropping probability as well as unnecessary handoffs in heterogeneous wireless networks.