Seamless multimedia QoS across UMTS and WLANs

The main objective of this paper is to evaluate the conditions and restrictions under which seamless multimedia QoS provision across UMTS and IEEE 802.11e WLANs is feasible. For this purpose, we consider a practical interworking scenario, where UMTS subscribers with ongoing real-time video sessions handover to WLAN, and we study the feasibility of seamless continuity by means of simulation. We particularly quantify the maximum number of UMTS subscribers that can be admitted to the WLAN, subject to maintaining the same level of UMTS QoS and respecting the WLAN policies. Our results indicate that the WLAN can support seamless continuity of video sessions for a relatively small number of UMTS subscribers, which depends on the applied WLAN policy, access parameters and QoS requirements. In addition to this study, we do address several other issues that are equally important to seamless session continuity such as the QoS discrepancies across UMTS and WLAN. The framework for discussing these issues is created by considering a practical UMTS/WLAN interworking architecture.