Extensible mobile presence

Presence is regarded as an important enabler for novel services in third-generation wireless networks (3G) (e.g, instant messaging). Standardization in 3GPP has adopted the IETF model for presence but integrated it into 3G service reachability and control support. Similarly, alternative approaches (e.g., Wireless Village or Messenger/.NET) restrict the user's use of presence in other ways. The paper examines some fundamental properties of mobile presence, what support is available for mobile presence, and limitations caused by this support. Finally, I present an alternative user-centric approach, with an extensible mobile presence which is operator and provider independent, that removes these previous limitations.