Mobile ATM: A generic and flexible network infrastructure for 3G mobile services

This paper presents the concept of “mobile ATM,” a proposal for third-generation (3G) mobile communication network infrastructure capable of supporting flexible evolution of radio technologies from today's cellular and data services towards future wireless multimedia services. Mobile ATM provides generic mobility management and QoS-based transport capabilities suitable for integration of multiple radio access technologies including cellular voice, wireless data, and future broadband wireless services. The architecture of a mobile ATM network is outlined in terms of the newly-defined “W-UNI” interface at the radio link and “M-UNI” and “M-NNI” interfaces within the fixed network. The concept of a “proxy-UNI” interface which supports unified access for WATM and non-ATM mobile terminals through corresponding interworking functions (IWF) is explained, leading to an understanding of how different radio access technologies are supported by the same ATM-based core network infrastructure. Generic mechanisms for handoff and location management within the core mobile network are discussed, and related protocol extensions over the “W-UNI” and “M-UNI/NNI” interfaces are proposed. The issue of “crossover switch (COS)” selection in mobile ATM is considered, and a unified handoff signaling syntax which supports flexibility in COS selection is described. Typical signaling sequences for call connection and handoff using the proposed protocols are outlined. Experimental results from a proof-of-concept mobile ATM network prototype are presented in conclusion.