Evaluating the Raw Potential for Device-to-Device Caching via Co-location

Cellular service providers are under tremendous pressure to accommodate the burgeoning data needs of mobile subscribers. One intriguing solution is leveraging co-location, namely taking advantage of proximity between mobile devices for opportunistic collaboration. Co-location affords the usage of short range, low-power radio interfaces, avoiding expensive cellular interfaces in orthogonal device-to-device (D2D) channels. Taken one step further, could mobile devices exchange caches when in proximity, pre-staging popular content with one another? A first step to such research is understanding the potential with actual users. In this paper, we analyze our NetSense study of nearly two hundred smartphone users to explore the potential for pre-staging. We find that not only is the propagation velocity of data via co-location exchanges reasonable, the actual storage costs for pre-staging are also quite reasonable and within the normal free space of typical smartphone users.