Coded Caching for Smart Grid Enabled HetNets With Resource Allocation and Energy Cooperation

With the development of millions more small-cell base stations (SBSs) and billions of connected devices in the future wireless networks, the need for energy-efficient system design and operation will be even more compelling. This paper investigates the content caching, resource allocation and energy cooperation in coded cache enabled heterogeneous networks (HetNets), where SBSs with cache ability are powered by both conventional grids and renewable energy sources, and energy can be shared among SBSs via the smart grid. We formulate the joint optimization problem, aims at minimizing the conventional grid energy consumption while satisfying quality of service (QoS) requirements of users. To deal with the mixed integer non-linear optimization problem, the original problem is decomposed into three lower level problems, i.e., content caching, content delivery and energy cooperation. We first propose an alternative iterative algorithm to optimize content caching and content delivery by jointly applying convex optimization techniques and matching theory. Then, by discussing two representative energy cooperative scenarios of smart grid supported networks, we propose efficient energy cooperation algorithms for the two scenarios, respectively. Furthermore, the joint content caching, content delivery and energy cooperation optimization algorithms are developed to minimize the conventional grid energy consumption in the considered HetNets. Simulation results demonstrate that the joint algorithms can significantly reduce the conventional grid energy consumption compared with other benchmarks.