UMTS signaling over 802.11 wireless LAN

There are many architecture for integration of universal mobile telecommunications system (UMTS) and IEEE 802.11 networks. Some of the architectures have the UMTS network as a master network and the 802.11 network as slave network (the UMTS network is the "controlling" network), in tightly coupled or loosely coupled fashion. In these cases, UMTS signaling needs to be transported over 802.11. Challenges arise because the services provided by WLAN radio access layer are different from those provided by UMTS link and physical layers. In this paper, we discuss the design of an adaptation layer that goes beneath the radio resource control (RRC) sub-layer of UMTS. We suggest ways to map functionality and concepts to the reduced set of features provided by 802.11 and discuss the tradeoffs involved. We also explore mobility management issues and handoffs. Finally, we discuss a prototype laboratory implementation, and lessons learnt.