 RQAM, and 32-XQAM schemes. However, the analysis confined to non-SWIPT system model. In [17], authors evaluated the performance of MIMO system model along with SWIPT in terms of outage probability, average capacity, and SEP by considering imperfect CSI. To bridge the gap, authors in [13, 14] analyzed SWIPT-enabled MIMO relay networks through outage probability and asymptotic outage probability and throughput in the presence of channel estimation errors (CEEs) considering both the imperfect CSI and outdated CSI. In this chapter, we first discuss about the wireless energy harvesting techniques and energy harvesting models. To develop better understanding of the concepts, half-duplex relay-assisted MIMO system model is analyzed over generalized fading Nakagami-m channels. In addition, AF relaying protocol is used at the relay to leverage its low complexity with easy deployment [18]. To attain deeper insights into the EH system model, the impact of EH under practical scenarios such as imperfect channel state information (CSI) and feedback errors are discussed. Analysis of CEEs is presented in terms of system performance metrics such as outage probability and asymptotic outage probability and throughput. The impact of imperfect CSI along with the results is presented first, and later, the impact of feedback errors is discussed. 6 Energy Harvested Device-to-Device MIMO Systems for Beyond 5G 6.1.1 Wireless Energy Transmission Techniques The wireless energy transmission schemes are classified as follows [19]: Wireless Power Transfer (WPT): In the WPT scheme, only power is trans- mitted through a transmitter to charge their batteries, without establishing a communication link [7]. Wireless Powered Communication Network (WPCN): IN WPCN, energy is harvested from RF signals radiated by an energy transmitter at the wireless receivers, and the harvested energy is used for information exchange between the devices [8, 9]. It is also known as "harvest-then-transmit." SWIPT: In the SWIPT protocol, a hybrid transmitter is used for