Cache-Enabled Power Line Communication Networks: Caching Node Selection and Backhaul Energy Optimization
Yuwen Qian, Liuqiang Shi, Long Xing Shi, Kui Cai, Jun Li, Feng Shu · IEEE Transactions on Green Communications and Networking · 2020
Power line communication (PLC) advances smart grid technology by offering a convenient and efficient data transmission service. However, due to the severe PLC channel condition and ever-growing traffic load in the PLC backhaul, reliable communications among widely distributed in-home PLC users is highly energy-consuming. In this paper, we put forth a cache-enabled PLC network comprising a single master base station (MBS) and mutiple slave base stations (SBSs) each bound with an in-home network to alleviate the backhaul traffic load and reduce the backhaul energy consumption. In the proposed scheme, the SBSs with the local caches pre-download the popular contents from the MBS through the PLC backhaul, and the in-home users request the contents from nearby caching nodes (CNs) or the MBS. Apart from the cache-enabled PLC design, our contributions also lie in the selection of CNs and optimal content placement algorithm. First, we propose a selection algorithm to activate the SBSs with high influence as the CNs, according to a directed graph that models the requesting relations among all SBSs. Second, we design an optimal content placement algorithm to minimize the backhaul energy consumption for the contents with different sizes and user preferences. Simulation results show that our cache-enabled PLC scheme with the caching node selection and optimal content placement can dramatically reduce the backhaul energy consumption, compared with the existing caching strategies.