Vertical Handoff Decision Algorithms for Providing Optimized Performance in Heterogeneous Wireless Networks
SuKyoung Lee, Kotikalapudi Sriram, Kyungsoo Kim, JongHyup Lee, YoonHyuk Kim, Nada T. Golmie
There are currently a large variety of wireless access networks, including the emerging Vehicular Adhoc Networks (VANETs). A large variety of applications utilizing these networks will demand features such as real-time, high-availability and even instantaneous high-bandwidth in some cases. Therefore, it is imperative for network service providers to make the best possible use of the combined resources of available heterogeneous networks (WLAN, UMTS, VANETs, Wi-MAX, etc.) for connection support. When connections need to migrate between heterogeneous networks for performance and high-availability reasons, then seamless vertical handoff is a necessary first step. In the near future, vehicular and other mobile applications will expect seamless vertical handoff between heterogeneous access networks. With regard to vertical handoff performance, there is a critical need for developing algorithms for connection management and optimal resource allocation for seamless mobility. In this paper, we develop a vertical handoff decision algorithm that enables a wireless access network to not only balance the overall load among all attachment points (e.g., Base Stations (BSs) and Access Points (APs)) but also to maximize the collective battery lifetime of Mobile Nodes (MNs). Moreover, when ad-hoc mode is applied to 3/4G wireless data networks, VANETs and IEEE 802.11 WLANs for more seamless integration of heterogeneous wireless networks, we devise a route selection algorithm to forward data packets to the most appropriate AP in order to maximize the collective battery lifetime as well as maintain load balancing. Results based on a detailed performance evaluation study are also presented here to demonstrate the efficacy of the proposed algorithms.