Energy efficient, context-aware cache coding for mobile information-centric networks

In a mobile, intermittently connected information-centric network (ICN), users download files either from the original source or from caches assembled during previous downloads. Network coding has helped to increase download robustness and overcome "missing coupon" delays. Prior work has also shown that network coding depletes energy resources much faster than no coding. Our contribution here is to make coding more efficient, and to detect when it is not necessary, in order to prolong the life of mobile handhelds. In the network coding context, Cache Coding (i.e., coding performed only on fully cached files) can prevent pollution attacks without significantly reducing diversity and performance with respect to unrestricted code mixing. Cache Coding introduces the first important means to reduce energy consumption by avoiding the extremely processor-intensive homomorphic code used in conventional unrestricted mixing networks. Our second contribution is to detect when Cache Coding is not required and disable it to save precious energy. The proposed Context-Aware Cache Coding (CACC) toggles between using Cache Coding and no coding based on the current network context (e.g., mobility, error rates, file size, etc). Our CACC implementation on Android devices demonstrates that the new scheme improves upon network coding's file delivery rate while keeping energy consumption in check.