Abstract
Mobile devices are getting increasingly popular all over the world, including developing countries, where mobile users rarely have the Internet access. In this paper, we propose a Challenged Content Delivery Network (CCDN) to opportunistically distribute news reports to mobile users with intermittent Internet access. In particular, we formulate an optimization problem to compute the distribution plans for individual mobile users, so as to maximize the overall user experience under various resource constraints. Our formulation jointly considers the characteristics of news reports, mobile users, and intermittent networks. We present a distribution planning algorithm based on the multidimensional knapsack problem, and we develop several online heuristics to adapt to the system and network dynamics. We conduct extensive trace-driven simulations to evaluate our proposed CCDN, which demonstrate that our algorithm: (i) outperforms the baseline algorithms by 55% to 10 times in terms of user experience, (ii) achieves higher system efficiency than the baseline algorithm--by 37% to 20 times, and (iii) terminates in 12 minutes for a medium-size network of 150 users. We envision that our CCDN will allow news providers to reach out to more mobile users, and mobile users to watch news reports without always-on Internet access.