Design and Implementation of Cooperative Caching in Wireless Peer to Peer Networks

Data caching strategy for ad hoc networks whose nodes exchange information items in a peer-to-peer fashion. Data caching is a fully distributed scheme where each node, upon receiving requested information, determines the cache drop time of the information or which content to replace to make room for the newly arrived information. These decisions are made depending on the perceived presence of the content in the nodes proximity, whose estimation does not cause any additional overhead to the information sharing system. We devise a strategy where nodes, independent of each other, decide whether to cache some content and for how long. In the case of small-sized caches, we aim to design a content replacement strategy that allows nodes to successfully store newly received information while maintaining the good performance of the content distribution system. Under both conditions, each node takes decisions according to its perception of what nearby users may store in their caches and with the aim of differentiating its own cache content from the other nodes’. The result is the creation of content diversity within the nodes neighbourhood so that a requesting user likely finds the desired information nearby. We simulate our caching algorithms in different ad hoc network scenarios and compare them with other caching schemes, showing that our solution succeeds in creating the desired content Diversity , thus leading to a resource-efficient information access.