Capacity of Content-Centric Hybrid Wireless Networks

In this paper, we investigate the capacity scaling laws of content-centric hybrid wireless networks, where users aim to retrieve content stored in the network rather than to maintain source-destination communication. A total of n nodes that have limited storage capacities are assumed to be independently and uniformly distributed in the square area. The storage at in each node is used to cache contents according to proposed caching schemes. A total of m-base stations are regularly placed and act as relays during the content retrieving process. Two different content access schemes are considered: homogeneous content access scheme, where each content is requested and cached with equal probability; and heterogenous content access scheme, where the cached probability of each content is different and the requested contents follow a Zipf content popularity distribution. We present the closed form capacity formulae for the two different content access schemes in order sense, respectively. We also discuss the impact of the number of nodes n, the number of base stations m, the storage capacities of nodes C, cached probability of content qj, and content popularity distribution pj on the capacity scaling. The capacity can be improved by increasing the storage capacities of nodes and adding base stations in the networks under homogeneous content access scheme. Under the heterogeneous content access scheme, increasing the cached probability of content and adding the base stations in the networks can effectively improve the capacity. We also present the capacity under different exponent of content popularity distribution. Finally, we compare our results with previous work, which appear as special cases of our work.