Exploiting caching and cross-layer transitions for content delivery in wireless multihop networks

One of the key challenges in wireless communications is handling the ever growing traffic demand. A large fraction of this traffic is induced by popular content. One way to face this challenge is mobile content caching which improves the system performance by caching content closer to the user. The benefit of content caching depends on the applied content delivery strategy. In this paper, we investigate a scenario where multiple destinations are concurrently requesting a content, which is already cached at mobile devices and then delivered over a wireless multihop network. We propose a content delivery framework which jointly exploits content already cached at mobile devices as well as switching between mechanisms at the physical layer and the network layer in order to optimally deliver the content to all destinations under changing network conditions. In our framework, we use a unified graph model to jointly model the network, the cached content and different mechanisms at the lower three layers. From the unified graph model, an optimization problem is formulated, which is used to find the optimal content delivery strategy. In our numerical evaluation, we show the combined gain of caching and the capability of switching between mechanisms by comparing with conventional schemes which either cannot switch between mechanisms or do not exploit caching.