In this paper we explore the use of prediction and delay-tolerance for offloading of large, socially recommended contents from 3G networks. We show that the two algorithms we design enable users to trade delay for energy and easily reduce battery consumption coming from 3G transfers of delay-tolerant content for 50%. We show that the real-time offloading requires Wi-Fi coverage of 3 to 4 times more cells, than our delay-tolerant algorithm. We find that both algorithms have lowest delay during the peak hours, when offloading is most needed. We also demonstrate how operators can benefit the collected data to offer cloud solutions, appealing to users (extending battery lifetime) and to the operators (load balancing between orthogonal technologies).
Finally, we believe that performance evaluation of the algorithms that uses a realistic application and a large data set is a contribution on its own. It helps community get better idea of the performance of a large scale delay tolerant application in a mobile network. It also allows us to gain insight into the possibilities of orthogonal 3G offloading, which is a topic that is likely to become increasingly important in the days to come.
Discussion and future work in this section we discuss some possible extensions of this study and a few viable directions for future fork. First, a complementary study of an application that relies on uploads could take advantage of the MMS entries available in the CDR logs. Second, adding the opportunistic component to the HotZones algorithm could additionally improve performance. The solid performance of the HotZones algorithm with very few Wi-Fi covered cells (30) shows that little infrastructure can match the performance of a comprehensive opportunistic solution. Although many factors (primarily increased storage) give greater capabilities to opportunistic nodes, the growing popularity of social networks and the increase in user generated content makes caching of relevant content difficult and complicates the design of pure opportunistic solutions.
It is also worth mentioning that although covering a cell with access points incurs certain costs, such a deployment could be facilitated by the use of home wireless routers that provide the Internet access to millions of operator’s customers. The fairness scheme proposed in [21] could be extended to mobile subscribers in order to reduce cost and provide better coverage.