Performance analysis of SWIPT-enabled cooperative NOMA networks for 5G and beyond wireless communications

Abstract

Wireless mobile communication and its applications have become a crucial part of our daily lives. With the increasing number of wireless devices, the number of users, and massive data traffic, the sig nificant challenges for today’s Fourth-Generation (4G) wireless communication system are the effec tive utilization of Radio Frequency (RF) spectrum and energy efficiency. Also, it is to be noted that the expected data rates for Fifth-Generation (5G) and beyond communication cannot be achieved using 4G technologies. This led to the development of various new technologies for 5G and beyond wire less communication. Three of the key technologies involved in 5G and beyond are Non-Orthogonal Multiple Access (NOMA), cooperative communication, and RF energy harvesting. The principal reason for using NOMA in 5G and beyond communication is its capability to serve multiple users using the same time and frequency resources. Two main techniques involved in NOMA are power-domain and code-domain. Power-domain in NOMA attains multiplexing in the power do main, whereas code-domain in NOMA attains multiplexing in the code domain. NOMA dominates typical Orthogonal Multiple Access (OMA) in terms of various aspects like spectral efficiency, con nectivity, latency, and fairness. Cooperative NOMA is an extended version of NOMA, which incorpo rates multiple or single relays into the NOMA networks to improve reliability. Since we are moving towards the design of advanced communication receivers for high data rate applications, the power consumption of wireless devices has become an important issue. Further, successive interference cancellation (SIC) technique involved in NOMA and complex signal processing techniques will quickly drain the battery life. Hence, to solve the problem of high energy consumption in 5G and beyond wireless systems, RF energy harvesting becomes a promising technology. Conventional energy harvesting techniques using solar power, wind energy, etc., are not reliable. Thus, non-conventional energy harvesting techniques such as Wireless Power Transfer (WPT) and Simultaneous Wireless Information and Power Transfer (SWIPT) will act as a solution. In WPT, the energy from powerful RF sources such as base stations, dedicated access points, etc., can be harvested to power individual wireless nodes. Further, SWIPT enables the wireless nodes to harvest the energy from incoming RF signals using time switching or power splitting techniques and transmit information using harvested energy. In a nutshell, cooperative NOMA and RF energy harvesting together will serve as promising candidates for 5G and beyond wireless communication. In our work, the performance analysis of cooperative NOMA networks with and without RF en ergy harvesting has been investigated over Rayleigh fading channel. We have derived mathematical expressions for performance metrics such as outage probability, system throughput, and ergodic ca pacity. The derived performance metrics have been validated using Monte-Carlo simulations. Further, the performance of the proposed system models have also analyzed for the cases with imperfect chan nel state information (CSI) and SIC, which exist in practical scenarios. Finally, various interesting inferences have been reported using the obtained performance metrics.