The Virtue of Patience: Offloading Topical Cellular Content through Opportunistic Links

Mobile data offloading is an approach to alleviating overloaded cellular traffic through alternative communication technologies on smartphones. Inspired by the prospect of spontaneous, peer-assisted, bulk data transfer through NFC or Wi-Fi Direct between proximate users\´ smartphones, we propose a model for mobile data offloading through the opportunistic proximity (e.g., Wi-Fi Direct) links with bounded content delivery delay and differential interests in content. Unlike the previous formulation of mobile data offloading as a target-set selection problem, which, essentially, asks the question "who (will download the content through the cellular link)," we ask "who" and "when." We present methods for individual users to locally estimate (their and their acquaintances\´) topological importance on the opportunistic proximity-link-based networks and aggregated interests in content. These factors are consolidated into a time-dependent function that embodies the concept of users\´ patience for the content. Each individual user, then, periodically make a probabilistic cellular download decision based on its patience at that time. Our motivation and insights are: 1) Involving topologically important, but otherwise disinterested, users in downloading and forwarding content helps improve offloading efficiency, 2) situation awareness embodied in the time-dependent patience function is desirable, since it allows users to react to hard-to-predict contact opportunities on the fly. Through trace-driven simulations, we corroborate our insights, and demonstrate the effectiveness of our proposed method in reducing cellular costs.