MobiCache: Cellular traffic offloading leveraging cooperative caching in mobile social networks

Offloading cellular traffic through mobile social networks has arisen as a promising way for relieving cellular networks. Prior studies mainly focused on caching data in a number of pre-selected helpers. However, such a strategy would fail when mobile users enter and leave the target area over time. In this paper, we examine the research decisions and design tradeoffs that arise when offloading cellular traffic in such a dynamic area of interest, referred to as a MobiArea, and we design an offloading framework, MobiCache, for maximizing cellular operators' revenues and minimizing the overhead imposed on mobile devices. On the user side, we propose a content floating-based cooperative caching strategy that caches data in geographical floating circles, instead of selected helpers in previous studies, to cope with the dynamics. A geographical routing scheme is designed for delivering data and queries towards floating circles. We also develop a cache replacement scheme to improve caching cost-effectiveness inside floating circles. On the operator side, query history and feedback are maintained for cellular operators to optimize framework parameters that maximize their revenues. Extensive trace-driven simulations show that, compared with a state-of-the-art scheme, MobiCache offloads up to 52% more traffic with 15% shorter delay and 6% less forwarding cost. The past few years have witnessed the explosive popularity of smart-phones and tablets. According to Cisco Visual Networking Index (VNI) [1], the mobile data traffic generated in 2014 was nearly 30 times the size of the entire global Internet in 2000, and global mobile traffic will grow at a compound annual growth rate of 57 percent from 2014 to 2019; in other words, it will increase 10-fold and reach 24.3 exabytes per month by 2019. This huge amount of data traffic, as a consequence, has degraded service quality and created immense pressure on the limited spectrum of cellular networks. For example, AT&T has already made several measures for throttling its customers [2]. One straightforward solution to tackling this problem would be deploying more base stations to expand cellular network capacity [3], which is limited, however, since it requires high financial input but gets low and diminishing returns. Addressing this problem needs some paradigm-altering approaches. Due to the inherent proximity-based sharing ability of mobile devices and the delay-tolerant nature of many cellular contents, offloading cellular traffic through mobile social networks (MSNs) [4] has arisen recently as a promising method for relieving cellular networks [5–11]. When users are rewarded with …