Seamless roaming between UMTS and IEEE 802.11 networks

Abstract

Mobile Internet access is currently available mainly using 2G/3G cellular telecommunication networks and wireless local area networks. WLANs are perceived as a local complement to slower, but widely available cellular networks, such as existing GSM/GPRS or future UMTS networks. To benefit from the advantages offered by both radio access networks, a mobile user should be able to seamlessly roam between them without the need to terminate already established Internet connections. The goal of this paper is to present an overview of the profitability of performing vertical handovers between UMTS and IEEE 802.11b using Mobile IP. Several simulations have been carried out using NS-2, which prove that handovers from IEEE 802.11b to UMTS can, under certain circumstances, be profitable not only when there is no more IEEE 802.11b coverage. Simulation results show that a mobile user should be able to roam between these networks depending on the current available channel bandwidth and quality, generated traffic type and number of users in both of them.