The virtue of selfishness: Device perspective on mobile data offloading

Direct device-to-device communication based on the `store-carry-forward´ paradigm is considered a feasible means for offloading mobile data traffic. Employing device-to-device communication however should satisfy user demand without greatly affecting battery lifetime. In order to provide satisfactory application throughput it is often assumed that nodes behave altruistic, and are willing to share contents for an infinite amount of time. In the context of energy savings, this assumption is overly optimistic. This work evaluates the performance of a publish/subscribe opportunistic content dissemination application that uses duty cycling for energy saving and allows nodes to behave in a selfish manner. Two types of selfishness are introduced: strict and mild. The paper presents the impact of selfishness on both application throughput and energy consumption via extensive trace-driven simulations, and demonstrates that introducing strictly selfish behavior on top of duty cycling leads to great decrease in energy consumption (up to 90% in certain cases) without causing significant loss in application throughput. Moreover, when the duration of the mild selfishness interval is chosen appropriately, mild selfishness can lead to even further decrease in energy consumption while at the same time increasing the application throughput.