On the Economic Value of Mobile Caching

Recent growth in user demand for mobile data has strained mobile network infrastructure. One possible solution is to use mobile (i.e., moving) devices to supplement existing infrastructure according to users' needs at different times and locations. For instance, vehicles can be used as communication relays or computation points. However, it is unclear how much value these devices add relative to their deployment costs: they may, for instance, interfere with existing network infrastructure, limiting the potential benefits. We take the first step towards quantifying the value of this supplemental infrastructure by examining the use case of mobile caches. We consider a network operator using both mobile (e.g., vehicular) and stationary (small cell) caches, and find the optimal amount of both types of caches under time- and location-varying user demands, as a function of the cache prices. In doing so, we account for interference between users' connections to the different caches, which requires solving a non-convex optimization problem. We show that there exists a threshold price above which no vehicular caches are purchased. Moreover, as the network operator's budget increases, vehicular caching yields little additional value beyond that provided by small cell caches. These results may help network operators and cache providers find conditions under which vehicles add value to existing networks.