Performance Evaluation of WLAN/Cellular Media Access for Mobile Voice Users under Random Mobility Models

With the proliferation of a diverse array of networks in the recent past, the heterogeneous environment is foreseen to serve mobile terminals (MT) in a complementary fashion at large. Multimodal MTs can now switch interfaces between Wireless Local Area Networks (WLAN) and the cellular media. In order to exploit the heterogeneity of the wireless environment, MTs require not only to have efficient medium access schemes but also smart medium selection methods. This paper aims at evaluating the performance of such schemes analytically. A practical yet tractable method of evaluating vertical handover (VH) algorithms was developed in the authors´ prior work yet a simplistic system scenario was addressed. In this paper, that framework is extended further to facilitate analyzing more realistic scenarios. Specifically, several random user mobility models are addressed here, and the prior assumptions of cellular ubiquity and stationarity of WLAN characteristics are relaxed. The performance of a Received Signal Strength Indicator (RSSI) based VH algorithm is evaluated in computing the WLAN usage efficiency and deriving the required signal strength thresholds for handover decisions that meet given target outage probabilities. An additional WLAN lifetime-based algorithm is also evaluated. Analytical results are validated by comparing them to simulation results.