We consider the problem of managing the information required to locate users in a wireless communication system, with a focus on designing and evaluating location management techniques that are efficient, scalable, and flexible. The three key contributions of this paper are: (1) A family of location management techniques, HiPER (for Hierarchical ProfilE Replication), that efficiently provide life-long (non-geographic) numbering with fast location lookup; (2) Pleiades, a scalable event-driven wireless system simulator with realistic calling and mobility patterns derived from several months of real traffic traces; and (3) multi-day simulations comparing our proposed location management techniques with current and previously proposed techniques on a realistic geographical and network topology. Research supported by the Center for Telecommunications and the Center for Integrated Systems at Stanford University, and by equipment grants from Digital and IBM Corporations. 1 Introduction I...

We consider per-user profile replication as a mechanism for faster location lookup of mobile users in a Personal Communications Service system. We present a minimum-cost maximum-flow based algorithm to compute the set of sites at which a user profile should be replicated given known calling and user mobility patterns. We then present schemes for replication plans that gracefully adapt to changes in the calling and mobility patterns. 1 Introduction In a Personal Communications Service (PCS) system, users place and receive calls through a wireless medium. Calls may deliver voice, data, text, facsimile, or video information [JLLM94]. PCS users are located in system-defined cells, which are bounded geographical areas. When a user places a call, the PCS infrastructure must route the call to the base-station located in the same cell as the callee. The base-station then transmits the data in the call to the PCS unit through the wireless medium. We consider the problem of locating users who...

We consider per-user profile replication as a mechanism for faster location lookup of mobile users in a Personal Communications Service system. We present a minimum-cost maximum-flow based algorithm to compute the set of sites at which a user profile should be replicated given known calling and user mobility patterns. We then present schemes for replication plans that gracefully adapt to changes in the calling and mobility patterns. We show the costs and benefits of our replication algorithm against previous location lookup approaches through analysis. We also simulate our algorithm against other location lookup algorithms on a realistic model of a geographical area to evaluate critical system performance measures. A notable aspect of our simulations is that we use well-validated models of user calling and mobility patterns. 1 Introduction In a Personal Communications Service (PCS) system, users place and receive calls through a wireless medium. Calls may deliver voice, data, text, fa...

This paper presents a novel location management technique, HOPPER, that is designed to support in a scalable and efficient manner nongeographical (lifelong) personal numbers in Personal Communications Services (PCS). Performance comparisons between our scheme and other schemes are derived from large scale simulations using a realistic traffic modeling framework for the ten largest cities of the United States. Results show that, in addition to inherently providing non-geographical numbers, the proposed scheme significantly improves lookup performance and requires relatively little database access and network signaling resources.

The explosive growth in wireless communications systems and the demand for advanced mobility features have created novel data management problems. Current schemes to address these problems rely on database organizations that have limited functionality and performance anomalies. We propose a new data management scheme that is flexible and scalable, and that is incrementally deployable so it can coexist with current data management standards. We compare our protocol against current standards and other suggested protocols using realistic calling and mobility patterns. To do so, we have built Pleiades, an extensible event driven simulator that is easily configurable to arbitrary geographies, networks, calling and mobility patterns, and data management schemes. We present, for the first time, models to closely approximate user calling and mobility patterns. These models are validated against real call traffic and urban vehicle data. Based on simulations for a representative 24-hour period i...

A study of the model and algorithms for handling location-dependent continuous queries