الفهرس 
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Abstract
Wireless sensor networks (WSNs) are used nowadays on a large scale for its low cost and efficiency in building many applications. These networks have limited resources i.e limited memory, battery power (energy) and low bandwidth; these limitations make these networks suffer from many problems such as low data availability and limited accessibility, long latency and frequent network failure. Several techniques exist to overcome these problems and to increase the efficiency. One of these techniques is the cooperative caching for sensed data; this is a significant process to store the frequently accessed data items in the WSNs. This thesis suggests a novel technique for caching data in cluster-based wireless network called Caching group Scheme (CGS) that is based on cooperative caching to cache data. The scheme can exploit the Cache of all nodes in caching group as one cache in each cluster to form cumulative cache and the cluster head acts as just a router for the data to the sink node; which enhances the load distribution in each cluster and reduces the query latency and energy consumption of the nodes thereby prolongs the lifetime of the network. The scheme includes a cache discovery process which uses cache discovery algorithm that is developed to ensure that a requested data is returned from the nearest cache or source, also it has an admission control to prevent high data replication and minimize the distance between the sink node and the source.