## 2 Literature Review  
Intelligent surfaces that can be reconfigured are also envisaged as the massive MIMO 2.0 solution in 6G and are being studied in [14]. In [14], a comprehensive overview of the key enablers for the future generation of wireless networks, a description of their essential uses, and an overview of the existing and future research and development of these technologies is provided. An approach for configuring and standardizing next-generation wireless systems based on transmission through RIS that intentionally change the phases of incident waves is presented in [11]. Dual-hop (DH) and access point (AP)-based RIS configurations are presented and implemented in [11], where the findings prove that RIS can improve the symbol error rate performance especially at low signal-to-noise ratio (SNR) regions. In [15], blindness compensation is investigated using RIS for millimeter wave wireless networks. An algorithm based on stochastic gradient descent was proposed in this work for locating and orienting single and multi-RIS systems optimally. A real-time RIS prototype with 160 elements for sub-6 GHz is implemented and its performance is evaluated in [16]. Future directions to improve the performance of beamforming are also listed in [16]. A review of recent developments in RIS hardware systems, real-time \begin{table}
\begin{tabular}{c c} \hline \hline
**Symbol** & **Description** \\ \hline \(u_{i}\) & Channel between BS and RIS \\ \(v_{i}\) & Channel between RIS and user equipment (UE) \\ \(\alpha_{i}\) & Power allocation factor assigned to user \(i\) \\ \(x_{s}\) & Combined transmited signal \\ \(y_{i}\) & The received signal at user \(i\) \\ \(n_{i}\) & Complex Gaussian noise added at user \(i\) \\ \(L\) & Overall gain of the channel of user 1 \\ \(M\) & Overall gain of the channel of user 2 \\ \(p_{i}^{\text{$\otimes$}_{R}}\) & Probability of outage of user \(i\) for smart reflector (SR) scenario \\ \(p_{i}^{\text{PNOMA}}\) & Probability of outage of user \(i\) for FNOMA system \\ \(p_{i}^{\text{ONOMA}}\) & Probability of outage of user \(i\) for ONOMA system \\ \(\text{D}_{i}\) & Desired rate of user \(i\) \\ \(\alpha_{i}^{\text{$\otimes$}_{input}}\) & Sub-optimal power allocated to user \(i\) \\ \(\alpha_{i}^{\text{$\otimes$}_{opt}}\) & Optimal power allocated to user \(i\) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: List of symbols. considerations, and modeling of RIS systems is provided in [17]. In [18], an analytical study is conducted on a multiple-user MIMO wireless communication system that utilizes a RIS. A joint coherent/non coherent scheme is also explored in this study, examining the trade-off between performance and complexity. The article [7] focused on the evolution of NOMA and how it will meet the overgrowing requirements of next-generation wireless networks. An examination of the theoretic capacity bounds of NOMA, additional requirements and potential candidates for next-generation multiple access are presented. After evaluating the most recent research contributions on NOMA, the authors analyzed the potential of the technology, how it interacts with other new physical layering approaches, and the effect of utilizing multi-antenna system at DL or uplink (UL) [7]. There are several topics discussed in [19], including fundamentals of NOMA, the effects of incorporating multiple antennas at UL and DL, comparisons between orthogonal multiple access (OMA) and NOMA techniques, and NOMA categories such as power domain and code domain. It also discusses distinct resource sharing methodologies and power allocation strategies for NOMA. The concept of MIMO-NOMA and its limitations and directions for future research in this area by integrating NOMA with massive/millimeter wave MIMO are discussed in [20]. In [21], NOMA is integrated with RIS to improve bit error rate (BER) performance over conventional NOMA systems. A DL RIS-NOMA system is implemented in [22]. RIS-NOMA performs better than traditional NOMA is demonstrated in this work.