Vertical handoff in heterogeneous wireless networks: A tutorial

The Heterogeneous Wireless Network is a hierarchical structure of different wireless networks. The wireless networks are differ in terms of network coverage, capacity, bandwidth, technology and network operator. In such an environment when a mobile terminal equipped with multiple network interfaces leaves one wireless network and connect to another different wireless network, a Vertical Handoff (VHO) occurred. But when to perform, where to perform and on what basis to perform the VHO, are the main questions which needs to be decided to perform an efficient VHO in order to maximize both the user perceived Quality of Service (QoS) & Quality of Experience (QoE). In this regard the selection of appropriate handoff decision attributes and the evaluation methods plays an important role. This paper presents all these aspects of VHO in a concise way. It evaluate the effect of various handoff decision attributes and their respective user preferences on vertical handoffs using various Multi Attribute Decision Method (MADM) based techniques. The Summative Additive Weighting (SAW) with Elimination Factors results in minimum number of handoffs in all situations.