Optimal Caching in Multicast 5G Networks with Opportunistic Spectrum Access

Abstract

Cache-enabled small base station (SBS) densification is foreseen as a key component of 5G cellular networks. This architecture enables storing popular files at the network edge (i.e., SBS caches), which empowers local communication and alleviates traffic congestions at the core/backhaul network. This paper develops a mathematical framework, based on stochastic geometry, to characterize the hit probability of a cache-enabled multicast 5G network with SBS multi-channel capabilities and opportunistic spectrum access. To this end, we first derive the hit probability by characterizing opportunistic spectrum access success probabilities, service distance distributions, and coverage probabilities. The optimal caching distribution to maximize the hit probability is then computed. The performance and trade-offs of the derived optimal caching distributions are then assessed and compared with two widely employed caching distribution schemes, namely uniform and Zipf caching, through numerical results and extensive simulations. It is shown that the Zipf caching almost optimal only in scenarios with large number of available channels and large cache sizes.

Caching and Multicasting for Fog Radio Access Networks

“…Note that content m is already requested by u 0 . Here, the conditional PMF of K 0 follows Poisson binomial distribution [43]. Thus, we have…”

“…Therefore, the condition on D 0,0 = d can be removed to calculate q κ,m,0 as follows q κ,m,0 (p) = R 0 q κ,m,0,D 0,0 (p, d) f D 0,0 (d)dd (41) Therefore, the proof is completed. Following the same steps of Appendix E, q κ,a,0,D a,0 (p, d) and q C,a,D C,a (p, d) can be obtained as in (42) and (43), as shown at the bottom of the page, respectively, where s = Next, we remove the conditions on the distance to obtain q κ,a,0, (p) and q C,a (p) as follows q κ,a,0 (p) =…”

Multidimensional Content Modeling and Caching in D2D Edge Networks

“…The emergence of content-centric networking requires popularity profiling of contents. In the literature, the Zipf distribution Zipf (s, N ) is widely used for generic modeling of content requests [5], [16]. Here, N stands for the total number of contents in the system while s determines the skewness of the distribution.…”

Optimal Caching in 5G Networks With Opportunistic Spectrum Access

“…A fundamental and widely employed design objective in data-centric networks is to maximize the probability of users finding requested popular files in the cache of an accessible edge SBS, also known as the hit probability 1 . More precisely, the hit probability is defined by the joint event of finding a SBS that i) is caching the requested popular file; and ii) is capable of serving the requesting user with at least a minimum pre-defined threshold of signal-to-interference-plus-noise-ratio (SINR).…”