Generic vertical handoff decision function for heterogeneous wireless

As mobile wireless networks increase in popularity and pervasiveness, we are facing the challenge of integration of diverse wireless networks such as WLANs and WWANs. Consequently, it is becoming progressively more important to arrive at a vertical handoff solution where users can move among various types of networks efficiently and seamlessly. The ability to remain connected as a mobile device roams across different types of networks still remains an unachieved objective. Frequently, just choosing the best network to connect to, is a challenging problem due to the large number of network characteristics that need to be considered. Identifying these decision factors is therefore one of the principal objectives for seamless mobility. In this paper, we discuss the different factors and metric qualities that give an indication of whether or not a handoff is needed. We then describe a vertical handoff decision function, VHDF, which enables devices to assign weights to different network factors such as monetary cost, quality of service, power requirements, personal preference, etc.