PCach: The Case for Pre-Caching your Mobile Data

摘要

We present PCach, a smartphone application designed to relieve the congestion in cellular networks resulting from the exponential growth of mobile data traffic. The basic idea underlying PCach is simple: use Wi-Fi to proactively cache content on the smartphone's memory, which otherwise would have been delivered through the cellular network during the next Wi-Fi coverage time gap. However, it leads to several challenging questions, including how much mobile data actually flows through cellular networks, how much data can be precached, and when and what to pre-cache. By analysing the extensive MACACO measurement dataset, our analysis shows that the median smartphone user transfers 15% of her data via the cellular network and that up to 80% of it could be pre-cached via Wi-Fi. From our empirical observations, we introduce an algorithm that can run stand-alone on off-the-shelf smartphones and predict with good accuracy when and what to pre-cache.