Location Assisted Vertical Handover Algorithm for QoS Optimization in End-to-end Connections

When devices are mobile, they potentially move within range of several different wireless networks, which are not utilized due to security, inactive radios or it is just plain cumbersome for the user to exploit them. This paper proposes a vertical handover algorithm to utilize these networks, which selects the best available network at a given time, factoring in prediction of user movement, energy consumption, QoS of connections and application demand for the end-to-end connection in a (multiple) client/server setting. The algorithm allows support for different mechanisms of interaction, where we in this paper focus on 1) peer-to-peer in a WLAN setting, 2) p2p behind NAT and 3) what we call a server bounce mechanism. The algorithm is supported by a User-specific Virtual Network to obtain required network state information. Experimental tests are conducted, using both simulations and actual implementation on Android based tablets. The simulations cover a wide range of scenarios for two mobile users in an urban area with ubiquitous cellular coverage, and shows our algorithm leads to increased throughput, with fewer handovers, when considering the end-to-end connection than to other handover schemes. The implementation utilizing real world networks, shows the feasibility of the algorithm due to its low complexity compared to other algorithms.