Broadcasting and prefetching schemes for location dependent information services

Abstract

The results of location-dependent queries(LDQ) generally depend on the current locations of query issuers. Many mechanisms, such as broadcast scheme, prefetching scheme, or caching scheme have been developed to improve system performance and provide better service for location dependent information services(LDISs). However, the client's mobility may lead to inconsistency problems. In this paper, we introduce the broadcast-based LDIS scheme(BBS) in the mobile computing environment. In the BBS, broadcasting data items are sorted sequentially based on their location and the server broadcasts the location dependent data(LDD) without additional indices. Then we present a data prefetching scheme and OBC(Object Boundary Circle) in order to reduce the client's tuning time. The performance for the proposed scheme is investigated by various environmental variables such as distributions of the data items, average speeds of the clients and the size of the service area. © Springer-Verlag Berlin Heidelberg 2005.