 Secure non-orthogonal multiple access: An interference engineering perspective. IEEE Netw. 35, 278-285 (2020) Chapter 6 Energy Harvested Device-to-Device Check for updates MIMO Systems for Beyond 5G Communication Parvez Shaik and Vimal Bhatia 6.1 Introduction Fifth generation (5G) wireless communications through massive machine-type communication (mMTC) enables billions of low-power low-complexity devices to connect [1, 2]. Performance of these energy-constrained devices is limited by their power source especially rechargeable batteries. The vested interest of the researchers toward the motive of automation in 5G communications and green communications has drawn significant attention in industry and academia. To address the energy requirement of the plethora of internet-of-things (IoT) devices, the devices should become self-sustainable and reliable by gleaning energy from the environment. Further, it is standardized by 5G standards and battery life perfor- mance indicators [3, 4]. Thus, simultaneous wireless information and power transfer (SWIPT)-enabled communications have drawn prominent research attention beyond 5G communications for providing energy wirelessly. Energy can be harvested from various sources such as mechanical energy, thermoelectric energy, solar/light energy, and electromagnetic (EM) energy [5]. Energy can be harvested by converting mechanical motion of the device such as vibration and displacement into electricity [6]. By converting the temperature gra- dient between human bodies and environment, energy can be harvested resulting in thermoelectric energy [6]. However, the energy harvested through these methods is insignificant and cannot enable communication. One of the most amiable resources is solar energy where the incident photons are converted into electricity through P. Shaik (X) Department of Electrical and Communication Engineering, Indian Institute of Sciences (IISc), Bangalore, India V. Bhatia Indian Institute of Technology Indore, Indore, Madhya Pradesh, India e-mail: vbhatia@iiti