Caching frequently accessed data at the client is an attractive technique for improving access time. In a mobile computing environment, client location becomes a piece of changing information. As such, location-dependent data may become obsolete due to data updates or client movements. Most of the previous work investigated cache invalidation issues related to data updates only, whereas few considered data inconsistency caused by client movements. This paper separates location-dependent data invalidation from traditional cache invalidation. For location-dependent invalidation, several approaches are proposed and their performance is studied by a set of simulation experiments. The results show that the proposed methods substantially outperform the NSI scheme which drops the cache contents entirely when hand-off.
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