2016/09/01 by Malak, Derya, Al-Shalash, Mazin, Andrews, Jeffrey G.
#FOS: Computer and information sciences #Information Theory (cs.IT) #Networking and Internet Architecture (cs.NI)
paper · doi:10.48550/arxiv.1609.00419
We study optimal geographic content placement for device-to-device (D2D) networks in which each file's popularity follows the Zipf distribution. The locations of the D2D users (caches) are modeled by a Poisson point process (PPP) and have limited communication range and finite storage. Inspired by the Matérn hard-core (type II) point process that captures pairwise interactions between nodes, we devise a novel spatially correlated caching strategy called \em hard-core placement (HCP) such that the D2D nodes caching the same file are never closer to each other than the \em exclusion radius. The exclusion radius plays the role of a substitute for caching probability. We derive and optimize the exclusion radii to maximize the \em hit probability, which is the probability that a given D2D node can find a desired file at another node's cache within its communication range. Contrasting it with independent content placement, which is used in most prior work, our HCP strategy often yields a significantly higher cache hit probability. We further demonstrate that the HCP strategy is effective for small cache sizes and a small communication radius, which are likely conditions for D2D.