## 1 Introduction  
Reconfigurable intelligent surfaces (RISs) have attracted considerable attention in recent years as a novel and fascinating area. As a developing technology, RIS can enhance wireless channel quality by adjusting the amplitude and phase of incident signals via low-cost and independently controllable passive elements on a surface. In the past few years, considerable research works have been conducted in response to the new research direction of RIS. For instance, the authors of [1] studied a RIS-aided single-cell wireless system, which minimizes the energy consumption of the system by optimizing the transmit beamforming at the base station (BS) and reflect beamforming at the RIS. In addition, the authors in [2, 3, 4] proposed several spectral efficient (SE) and energy efficient (EE) wireless solutions under various channel conditions. For example, the authors of [2] proposed two cost-effective approaches for optimizing the phase shifters of a RIS in a downlink multi-user communication system by using alternating maximization and non-convex optimization to improve SE and EE. These methods can also be used to reduce the bit error rate (BER) and enhance the achievable rate. However, the major limitation is that RISs can only reflect the signal,and the coverage area is constrained due to the physical characteristics. As a solution to this issue, the simultaneous transmitting and reflecting RISs (STAR-RIS) is proposed, which not only solves the challenge of omnidirectional coverage but also provides more degrees of freedom for controlling the STAR-RIS. Following this, several studies have been conducted on STAR-RIS-aided wireless communication systems. [PERSON] et al. in [PERSON] et al. (2019) applied STAR-RIS to unmanned aerial vehicle (UAV) networks to maximize achievable rates through the joint optimization of UAV trajectory and phase shifters. The authors in [PERSON] et al. (2019) investigated three operational protocols for STAR-RIS, and simulation results confirmed that the performance of STAR-RIS using the proposed protocols surpasses that of traditional RIS. Based on [PERSON] et al. (2019), the authors in [PERSON] et al. (2019) proposed an innovative emergency communication network for UAVs utilizing both STAR-RIS and non-orthogonal multiple access (NOMA). NOMA provides a significant advantage compared to conventional orthogonal multiple access schemes [PERSON] et al. (2019). Additionally, because of STAR-RIS's capability for both transmission and reflection, users in the STAR-RIS scenario can be divided into two categories as follows: transmission users and reflection users. Several works have combined the NOMA and STAR-RIS in light of this. For example, the authors in [PERSON] et al. (2019) jointly optimized both the position of the UAV and the passive beamforming of STAR-RIS to obtain a sum-rate maximization solution in STAR-RIS-aided NOMA networks. The authors in [PERSON] et al. (2019) proposed a NOMA system empowered by mobile STAR-RIS, which outperforms various other schemes in terms of average achievable rate. The authors in [PERSON] et al. (2019) developed a two-layer iterative algorithm to jointly optimize user pairing, decoding order, beamforming, and resource allocation in a STAR-RIS-assisted NOMA framework, significantly improving the minimum user rate compared to conventional schemes. The authors in [PERSON] et al. (2019) proposed a STAR-RIS-assisted NOMA system that jointly optimizes decoding order, power allocation, and beamforming to maximize system sum rate. A two-layer iterative algorithm was developed to efficiently solve the non-convex problem, yielding superior performance compared to conventional RIS-assisted NOMA and RIS-assisted orthogonal multiple access schemes. A detailed comparison of related works can be found in Table 1. However, most of the works considering NOMA face the following bottleneck.