Ergodic analysis of IRS-NOMA with inter-cell interference and Imperfect-CSI and SIC over Nakagami-m faded channel

Abstract

Future wireless technology requires higher data rates, low latency, and flexibility to provide services to users. To fulfil these demands, various multiple access techniques are proposed. Among these techniques, the non-orthogonal multiple access technique (NOMA) is providing better features compared to orthogonal multiple access (OMA) techniques, such as more number of radio resources with low latency. In NOMA based communication system, if a user is lying on the cell's edge, their performance is poor. Recently, intelligent reflecting surfaces (IRS)-NOMA system is introduced to enhance its performance. To implement IRS-NOMA in a real-time scenario, the impact of inter-cell interference and imperfect-channel state information (CSI) and successive interference cancellation (SIC) is very much required. In this work, we derived analytical expressions to evaluate the Ergodic capacity of the IRS-NOMA over the Nakagami-m faded channel by considering inter-cell interference, imperfect-CSI, and SIC. By considering these factors, this work offers a comprehensive understanding of the system's capabilities and limitations. Here, two user IRS-NOMA is considered and also evaluated the analytical results by varying fading parameter (m), number of interferers (K), error in CSI and SIC, and IRS elements. These results are also supported by simulated results.

Keywords

• NOMA
• Intelligent reflecting surfaces
• Interference
• Fading
• Ergodic capacity