Abstract
Non-orthogonal multiple access (NOMA) technology is expected to effectively improve the spectrum efficiency of fifth-generation and later wireless networks. As a new technology, reconfigurable Intelligent surfaces (RIS) can achieve high spectral and energy efficiency with a low cost in wireless networks. These are achieved by integrating a great quantity of low-cost passive reflective units (RUs) on the plane. In this article, in order to meet the needs of high efficiency, low power consumption, and wide coverage, we combine RIS-assisted NOMA technology with the internet of things (IoT). Because in the actual wireless communication system, the residual hardware impairment (RHI) characteristics of the actual transceiver equipment will have an important impact on system secrecy performance. Therefore, the study will propose a single eavesdropper RIS-assisted downlink NOMA system with RHI (E-RHI-RIS-NOMA). The study will also investigate the impact of RHI on the physical layer security (PLS) performance of the system and the closed-form expression of the user's secrecy outage probability (SOP) is derived. Finally, the simulation results show that 1) the main factors affecting the SOP are the quantity of RUs in RIS, the transmit SNR, and the target data rate, 2) it is proved that the hardware impairment of the transceiver harms the system's secrecy outage performance while the severity of the impact of RHI on the system performance depends on the transmit SNR and target data rate. Moreover, RHI at different nodes has a different influence on system secrecy performance. 3) the system performance of RIS relying on NOMA is improved compared with orthogonal multiple access (OMA) and conventional NOMA.
Highlights
I NTERNET of Things (IoT) technology is getting a lot of attention because of its huge potential to connect billions of devices in numerous applications [1]
The intelligent radio environment is a kind of wireless network that transforms wireless network environment into reconfigurable intelligent space, which is controlled by telecom operators and plays a positive role in information transmis
Based on the E-RIS-assisted NOMA system with non-ideal (RHI)-Reconfigurable intelligent surfaces (RIS)-non-orthogonal multiple access (NOMA) system model proposed in Fig 1, this section first analyzes the channel statistical characteristics of the composite variables involved in the paper, as the basis for the subsequent analysis of the secrecy outage performance
Summary
I NTERNET of Things (IoT) technology is getting a lot of attention because of its huge potential to connect billions of devices in numerous applications [1]. According to the existing research work, the hardware impairment has seriously affected the performance of the wireless communication system with RIS-assisted transmission. To the best of our knowledge, the secrecy performance of RIS-assisted NOMA system with non-ideal (RHI) hardware condition has not been investigated in the existing literature. Based on this motivation, this work investigates how the security performance of RIS-assisted NOMA system is affected by RHI. In this case of high SNR and high target data rate, RHI have a more significant influence on the secrecy performance of the system, and when the power allocation coefficient is taken at different values, the impact on system security performance varies.
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