SWIPT Techniques in Multi-tier D2D Networks for Energy Efficiency

Energy efficiency is an important metric in the upcoming 5G scenario due to the increasing energy costs and the focus on sustainable technology. Paradigms like device-to-device communication and heterogeneous networks help in achieving high data rates, user capacity, and coverage promised by 5G, while simultaneous wireless information and power transfer (SWIPT) offers a green technique to have dual usage of the incoming RF wave in transferring energy and information simultaneously. SWIPT also helps in converting the harmful interference, incurred by the frequency reuse of D2D tier underlaying the Hetnet, into energy that can be stored for the future. This paper presents the use of two techniques of SWIPT, namely power splitting SWIPT and time splitting SWIPT, and gives a resource allocation scheme so as to improve the energy efficiency of the D2D tier. Minimum data rates are ensured for all users, cellular and D2D. Maximum bipartite matching is used for subcarrier allocation to cellular users and a stable many-to-one matching game is used for subcarrier allocation to D2D users. Extensive simulations are done to compare the performance of the two approaches.