## 2 Related Works  
Numerous research studies have been conducted on NOMA, MEC, and 6G communications. To our knowledge, however, a comprehensive evaluation of the literature on NOMA-based mobile edge computing in 6G communications has not been done.  
[PERSON] et al. [86] completed a thorough categorization analysis of research in the power and code domains on NOMA-related energy-saving solutions. They also considered developing plans to use cutting-edge methods to increase the energy efficiency of current green NOMA programs. Finally, they determined upcoming difficulties and strategies for an energy-efficient NOMA since NOMA has been identified as a critical technology for fifth-generation wireless (5G) networks.  
[PERSON], [PERSON], and [PERSON] [87] primarily investigate the implementation of NOMA structures on software-defined radio (SDR) schemes. This investigation thoroughly evaluates NOMA's origins, current developments, and potential future research areas. Mathematical analysis is presented for several successive interference cancellations (SIC) receivers, including the ideal SIC recipient, the symbol-level SIC receiver, and the codeword-level SIC receiver.  
[PERSON] et al. [88] thoroughly investigated 6G networks. They examined the 6G networks' utilization, essential services, enabling technology, and upcoming difficulties. They started by talking about the demand for 6G networks. The following section discusses prospective 6G demands, trends, and current 6G-related research initiatives, such as B. Touch Internet and terahertz (THz). There will also be presentations of applications, new services, important enabling technologies, and key performance metrics for 6G networks. Finally, several possibly unsolved difficulties for upcoming 6G networks are also given.  
[PERSON] et al. [89] investigated the evolution of Next Generation Multiple Access (NGMA), focusing particularly on the change from NOMA to NGMA. Specifically, the authors explore many potential candidate approaches after first addressing the essential capability restrictions of NOMA and outlining the innovative specifications for NGMA. We also offer a summary of existing investigation exertions on multi-antenna procedures for NOMA, possible upcoming utilization situations of NOMA, and the interaction amid NOMA and further upcoming physical layer approaches in light of the increased compatibility and litteness of NOMA. In addition, we talk about sophisticated mathematical techniques for NOMA communication design.  
[PERSON] et al. [90] thoroughly analysed the most important research papers on UAV technology utilization connected to MEC-allowed or aided networks. It discusses how new IoT applications might benefit from the UAV-enabled MEC architecture and how DL and ML play a part in overcoming different restrictions like latency, task shifting, energy requirements, and security.  
After reviewing these surveys, our contribution will focus on analysing resource and power allocation, latency, energy consumption, and the allocation of computing and energy-saving resources while also suggesting a more effective allocation of resources and energy. In summary, we concentrate on the present methods, unanswered issues, and future areas of study for NOMA-enabled MECs in 6G communications. Additionally, we will offer suggestions for researchers who want to do this type of research. The literature relating to this survey reviewed is abridged in Table 1.  
It was deduced from the literature review that many authors did not follow the systematic literature review procedure, which involves using the PRISMA method for a thorough investigation. Hence, in this study, we have proposed to consider the SLR using the PRISMA method to analyse the articles for the study.