A novel caching scheme for Internet based mobile ad hoc networks

Internet based mobile ad hoc network (IMANET) is an emerging technique that combines a wired network (e.g. Internet) and a mobile ad hoc network (manet) for developing a ubiquitous communication infrastructure. However, imanet has several limitations to fulfill users´ demands to access various kinds of information such as limited accessibility to the wired Internet, insufficient wireless bandwidth, and longer message latency. In this paper, we address the issues involved in information search and access in IMANET. A broadcast based simple search (SS) algorithm and an aggregate caching mechanism are proposed for improving the information accessibility and reducing average communication latency in imanet. As part of the aggregate cache, a cache admission control policy and a cache replacement policy, called time and distance sensitive (TDS) replacement, are developed to reduce the cache miss ratio and improve the information accessibility. We evaluate the impact of caching, cache management, and access points, which are connected to the Internet, through extensive simulation. The simulation results indicate that the proposed aggregate cache can significantly improve an imanet performance in terms of throughput and average number of hops to access data. In particular, with aggregate caching, more than 200% improvement in throughput is achieved compared to the imanet with no cache case, when the access pattern follows a Zipf distribution.