## 1 Introduction  
Researchers have thought about the 6G generation of cellular networks, which can handle significantly greater data rates and numerous future applications [1; 2; 3], while 5G networks are still in the deployment phase [4; 5; 6]. The three main application services that 5G communications focus on providing are improving mobile broadband (eMBB), supplying ultra-reliable low latency communications (URLLC), and providing massive machine-type communications (mMTC). Contrarily, 6G networks may run programs that enable augmented reality, virtual reality, linked and autonomous drones and cars, and intelligent and automated devices. Compared to the gigabit per second data rate offered by 5G networks, these networks necessitate a data throughput of up to terabit per second for all of them [7; 8]. The utilization of the tera-Hz band is a crucial component of 6G networks. 5G networks currently use millimetre-wave and sub-6 GHz spectrum. 6G networks offer sub-1 ms latency and 99.9999% reliability, enabling universal communication and several future uses. To improve communication capacity, offer better channel estimations for effective signal transfer, and enable dependable data propagation, 6G will use full-duplex communication and other physical layer technologies [9; 10; 11]. Additionally, 6G will leverage AI to make autonomous systems possible, distributed learning techniques to boost precision, big data analytics for forecast and wise decision-making, and the realization of smart cloud, fog, and edge nodes [12; 13; 14; 15]. For 6G networks, energy efficiency will be a significant problem [16; 17; 18]. Supporting widespread IoT applications is one of the primary causes of the need for increased power consumption [19]. Future network nodes, such as Internet of Things (IoT) gadgets and fog nodes, will have a lot of work to do, increasing power consumption [20; 21]. Adopting Tera Hz communications, a short-range communications technology presents another energy-related difficulty for 6G networks. Higher data speeds are possible with the tera-Hz transmission, but it is severely attenuated because of propagation losses and molecular absorption losses [18; 22]. 6G networks will prioritize energy-efficient schemes by delivering less-power communications, new energy harvesting (EH) procedures, and energy-saving computing approaches. 6G networks, which will increase connection, boost computational power, and enhance detection and location accuracy, will also enable massive IoT applications. 6G could offer tera-Hz communications, incredibly high data throughput, and extremely small latency because of its capabilities and technologies [23]. NOMA has been recommended as a substitute for traditional orthogonal multiple access (OMA) because it can improve the number of authorized individuals, bandwidth effectiveness, and reduce downtime [24; 25]. NOMA's fundamental notion is to allow many individuals to transmit signals simultaneously on a particular bandwidth block. The successive interference cancellation (SIC) technique is used as a multiuser authentication strategy at the reception point to reduce disturbance [26; 27]. Integrating NOMA and MEC has become a promising way to deliver efficient transmission and processing to many devices. Implementing NOMA enables multiple clients to synchronously transfer their computational operations to a machine located at the network's periphery, thereby increasing computational capability and effectiveness. A significant amount of investigation has been committed to improving MEC's efficacy in wireless connections by employing NOMA techniques. [28; 29; 30]. The developers of [28] sought to reduce system energy usage by enhancing people gathering, resource apportionment, and broadcast rules. The scholars of [29] jointly adjusted jobs and transmission periods to reduce structure interruption in NOMA-centered MEC connections.