Caching increases the capacity of wireless networks

Abstract Content Caching at the network edge, e.g., base stations and mobile devices, is a promising solution to meet the demand of massive mobile traffic growth. In this chapter, we focus on edge caching in a wireless ad hoc network without any infrastracture support, and study how content caching at mobile devices can help improve the network capacity. In wireless ad hoc networks, due to the interference between concurrent transmissions, the per-node capacity generally decreases with the increasing number of nodes in the network. Caching can help improve the network capacity, as it shortens the content transmission distance and reduces the communication interference. However, the fundamental performance limits of caching in wireless ad hoc networks have rarely been studied in an analytical manner. In this chapter, we first illustrate the benefit of caching under uniform content popularity, i.e., the capacity of wireless ad hoc networks with caching can remain constant even as the number of nodes in the network increases. Then, we generalize the results, evaluate how the distribution of the content popularity affects the per-node capacity, and derive different capacity scaling laws based on the skewness of the content popularity. Our results suggest that for wireless networks with caching, when contents have skewed popularity, increasing the number of nodes monotonically increases the per-node capacity.