Joint and Competitive Caching Designs in Large-Scale Multi-Tier Wireless Multicasting Networks

Caching and multicasting are two promising methods to support massive content delivery in multi-tier wireless networks. In this paper, we consider a random caching and multicasting scheme with caching distributions in the two tiers as design parameters, to achieve efficient content dissemination in a two-tier large-scale cache-enabled wireless multicasting network. First, we derive tractable expressions for the successful transmission probabilities in the general region as well as the high SNR and high user density region, respectively, utilizing tools from stochastic geometry. Then, for the case of a single operator for the two tiers, we formulate the optimal joint caching design problem to maximize the successful transmission probability in the asymptotic region, which is nonconvex in general. By using the block successive approximate optimization technique, we develop an iterative algorithm, which is shown to converge to a stationary point. Next, for the case of two different operators, one for each tier, we formulate the competitive caching design game where each tier maximizes its successful transmission probability in the asymptotic region. We show that the game has a unique Nash equilibrium (NE) and develop an iterative algorithm, which is shown to converge to the NE under a mild condition. Finally, by numerical simulations, we show that the proposed designs achieve significant gains over existing schemes.Comment: 30 pages, 6 pages, submitted to IEEE GLOBECOM 2017 and IEEE Trans. Commo

A framework for mobile data offloading to leased cache-endowed small cell networks

Cache-endowed small cell networks constitute a timely and effective solution for mobile network operators (MNOs) who strive to serve the massive content demand of the mobile users. However, the deployment of small cell base stations (SBSs) requires significant economic investments, while site acquisition issues render it infeasible in several cases. Yet, one potentially explosive factor for network expansion remains unexploited, namely, an increasing number of residential users install in their premises privately-owned SBSs (femtocell or WiFi access points) in order to serve their own needs. In this work, we envision an MNO offering incentives to the SBS owners to cache and deliver content items requested by the nearby mobile users. We model the interaction between the MNO and the SBS owners as a Stackelberg game, and show that the incentive design problem requires to know the content caching policy, which in turn should be jointly derived with the request routing policy. We then introduce a framework for the joint derivation of incentive, caching and routing policies. Numerical results indicate that our mechanism provides a substantial potential for reducing the MNO's costs, depending on the willingness of the SBS owners to lease their resources and the spatio temporal characteristics of the mobile data demand. © 2014 IEEE