Signal Optimization and Energy-Efficient Design of Reconfigurable Intelligent Surface (RIS)-Assisted Non-Orthogonal Multiple Access (NOMA) Networks: A Simulation-Based Investigation

Abstract

This study looks at signal optimization and energy-efficient design in Reconfigurable Intelligent Surface (RIS)-assisted Non-Orthogonal Multiple Access (NOMA) networks using simulation. RIS improves wireless communication by reflecting signals intelligently. This boosts spectral efficiency and cuts down on inter-user interference, which are major challenges in NOMA systems. The researchers developed a model based on Simulink to evaluate performance across different user distances. They compared traditional NOMA with RIS-assisted setups using various reflection methods. The results show that optimized RIS can boost signal strength by as much as 15 dB compared to non-RIS setups and by 7 to 8 dB compared to fixed-phase RIS. Spectral efficiency improved by 60 to 80%, rising from 2.5 bps/Hz to 4.6 bps/Hz. Energy consumption fell by about 30%, with power needs dropping from 130 mW to between 88 and 95 mW due to better signal direction. These improvements highlight the potential of RIS-assisted NOMA for better performance and energy savings. This makes it a good fit for next-generation wireless systems like 5G, 6G, IoT, and vehicular networks. The findings offer useful insights for configuring RIS effectively and allocating power, which supports scalable deployment in complicated communication settings.