Spectrum sharing and energy harvesting for IoT networks

Abstract

This thesis proposes a simultaneous wireless information and power transfer (SWIPT) enabled Internet of Things (IoT) based coordinated direct and relay (CDRT) transmission with non-orthogonal multiple access (NOMA) system. It incorporates overlay cognitive radio (CR) and time switching (TS)-based SWIPT technology to enhance spectrum utilization and energy efficiency. The proposed system comprises of a primary network with primary transmitter and its intended receivers (UE1, UE2), accompanied by an energy-constrained secondary transmitter, and its designated secondary receiver (IoT-U). The primary transmitter communicates directly with its strong user UE1 and exploits the secondary transmitter as an IoT-relay to communicate with a weak user UE2. The IoT-relay node employs TS-based receiver architecture and decode-and-forward protocol to convey the weak user’s information along with its own information by following the NOMA principle. The same system is also studied by considering power splitting protocol to provide novelty for the considered system model and also implemented caching scheme in the proposed system model. Also, the cache pre-fetches the primary and secondary popular file contents which reduces the data access delay and increases the transmission rate. The performance of the proposed system is evaluated in terms of outage probability, throughput and energy efficiency by considering both the perfect and imperfect successive interference cancellation at the legitimate users over Nakagami-m fading and in the second system model we implemented cache scheme over Rayleigh fading to provide better insights of the system model. Further, to improve the spectrum utilization we also studied the cooperation between primary and secondary networks via content caching scheme under Rayleigh fading channel. Moreover, the impact of key parameters is also highlighted, which lays the guidelines for the practical design of energy-efficient and spectrum-efficient futuristic wireless communication networks.