Performance Analysis of Vertical Handover Algorithm Based on Expected WLAN Lifetime

The widespread deployment of Wireless Local Area Networks (WLAN) over the last decade, and advances in wireless access technologies, have endowed handheld mobile terminals (MT) with multimodal connectivity features. Multimodal MTs can now switch interfaces between the WLAN and the cellular network, and select their network of choice in real-time. In order to exploit the heterogeneity of the wireless environment, MTs require efficient vertical handover (VH) algorithms. In this paper, we present an analytical method of evaluating VH algorithm performance for mobile voice users over heterogeneous environments. An algorithm that computes the expected WLAN-lifetime of an MT, and uses it along with the Received Signal Strength Indicator (RSSI) in determining the appropriate handover instance, is analyzed. The average number of handovers per crossover of the WLAN border region, and the average bandwidth available to the MT, are analytically derived and compared to simulation results.