Efficient Vertical Handoff in Heterogeneous Wireless Network

Integration of heterogeneous wireless technologies is cardinal area of research for next generation mobile networks. Considering the heterogeneous environment, Universal Mobile Telecommunication System (UMTS) of cellular technology and Wireless Local Area Networks (WLAN) (over IEEE 802.11) are the most promising networks which can be integrated to facilitate the seamless communication. However, integration of UMTS and WLAN involves some challenging issues such as mobility management and handoff decision making. Handoff decision making depends on various metrics such as available bandwidth, jitter, delay, energy, cost, etc. Moreover, handoffs need to have seamless connectivity while maintaining the acceptable quality of service in heterogeneous network. Various approaches have been proposed to address handoff decision making problem. This paper proposes a novel fuzzy rule based handoff decision making algorithm for meeting the requirements of heterogeneous networks. It considers WLAN and UMTS as two integrated network entities. The algorithm allows the Mobile Terminal (MT) to always get connected to the most energy efficient and cost-effective network evaluated on the basis of various handoff metrics such as energy, traffic and cost.