There is a growing interest in the research community in mechanisms that transport asynchronous transfer mode (ATM) cells over a wireless link (wireless-ATM), and in wireless access to ATM backbone networks (broadband wireless networking). This paper presents an architecture for broadband wireless networking that supports PCS (personal communication services) using an ATM backbone. We develop analytical and simulation models to measure the delay of PCS registration and call delivery. The performance models are illustrated with numerical examples that reveal the high sensitivity to the processing speed of network entities. Their agreement provides a first cut engineering approximation that can easily be applied to other networks and systems.

Current cellular subscribers have a geographic phone number (e.g., in AMPS and US digital cellular systems) or a number which contains the network provider's identity (e.g., in GSM), and whenever subscribers register or receive (and possibly, originate) a call, a home location register (HLR) database has to be queried. The wired infrastructure supports a function called global title translation (GTT) that converts the subscriber's number to an HLR database address. A special feature of next generation wireless access service will be to support personal communication services (PCS) and wireless subscribers with portable personal numbers, or nongeographic phone numbers (NGPNs), that do not indicate the service provider or HLR database serving the user. In addition, the GTT function may not be available when the wired backbone is an ATM network. Thus a key function required in future wireless access systems with wired ATM backbones will be the ability to translate an NGPN to the identity of the HLR which serves the subscriber, a process we call NGPN translation. We discuss the requirements of NGPN translation and some alternative schemes. We propose two schemes for fast, efficient, scalable and flexible NGPN translation which use ideas of dynamic hashing, caching, and indirection. The schemes use a hash function in the visiting location registers (VLRs) (or serving SCP) and a set of distributed translation servers which store the NGPN-to-HLR mapping. We discuss how the operations required to maintain the translation information can be performed. Finally, we perform a simplified analysis of the scalability of the alternative schemes as well as the hash-based schemes we propose.

Current cellular subscribers have a geographic phone number (e.g. in AMPS and US digital cellular systems) or a number which contains the network provider's identity (e.g. in GSM), and whenever subscribers register or receive (and possibly, originate) a call, a home location register (HLR) database has to be queried. A special feature of next generation wireless access service will be to support PCS and wireless subscribers with portable personal numbers, or non-geographic phone numbers (NGPN), that do not indicate the service provider or HLR database serving the user. In addition the global title translation (GTT) function that converts the subscriber's number to an HLR database address may not be available when the wired backbone is an ATM network. Thus a key function required will be to translate an NGPN to the ID of the HLR which serves the subscriber, a process we call NGPN translation. (Note that the same functionality is also needed for subscribers with local, portable phone numbers.) We discuss the requirements of NGPN translation and some alternative schemes. We propose a scheme for fast, efficient, scalable and flexible NGPN translation which applies ideas of dynamic hashing, caching, and indirection. The scheme uses a hash function in the visiting location registers (VLR) (or serving SCP) and a set of distributed translation servers which store the NGPN-to-HLR mapping.

Mobile intemetworking revolves around the premise that a mobile host (MH) will frequently attach to and detach from the Intemet, thus changing its addressfrequently.Location management in mobile intemetworking refers to the process of keeping track of the current addresses of MHs in the Intemet.Protocols proposedfor mobile intemetworking rely on a combination of searchesand updates for location management.Adrawback of these protocols is that they are not uniformly efficient over all possible call-to-mobility ratios (i.e., the relative frequency of searchesascompared to up- dates).Unimportant issue, therefore, ishowthe overall costs of location management can be reduced, regardless of the call-to-mobility ratio.The aim of this work is to explore a new and practical scheme for location management, with emphasis on network cost reduction.We makethe keyobservation thatwhile thepotential setof sources forthe MHmaybelmge, tiesetofsources thatagiven MH communicates most frequently with is very small.Based on this, we develop the concept of a working set o~hosts for the MH (similar to the working set concept in operating systems).An adaptive scheme of location management is proposed, that enables an MH to dynamically determine its working set, and trade-off routing and update costs in order to reduce the total cost.Comparative analysis of the proposed scheme, using simulation, shows its efficiency over a wide range of call-to-mobility ratios.