The various requirements in terms of data rates and latency in beyond 5G and 6G networks have motivated the integration of a variety of communications schemes and technologies to meet these requirements in such networks. Among these schemes are Terahertz (THz) communications, cooperative non-orthogonal multiple-access (NOMA)-enabled schemes, and mobile edge computing (MEC). THz communications offer abundant bandwidth for high-data-rate short-distance applications and NOMA-enabled schemes are promising schemes to realize the target spectral efficiencies and low latency requirements in future networks, while MEC would allow distributed processing and data offloading for the emerging applications in these networks. In this paper, an energy-efficient scheme of multi-user NOMA-assisted cooperative THz single-input multiple-output (SIMO) MEC systems is proposed to allow the uplink transmission of offloaded data from the far cell-edge users to the more computing resources in the base station (BS) through the cell-center users. To reinforce the performance of the proposed scheme, two optimization problems are formulated and solved, namely, the first problem minimizes the total users' energy consumption while the second problem maximizes the total users' computation energy efficiency (CEE) for the proposed scheme. In both problems, the NOMA user pairing, the BS receive beamforming, the transmission time allocation, and the NOMA transmission power allocation coefficients are optimized, while taking into account the full-offloading requirements of each user as well as the predefined latency constraint of the system. The obtained results reveal new insights into the performance and design of multi-user NOMA-assisted cooperative THz-SIMO MEC systems.

翻译：超越5G和6G网络中数据速率与延迟的多样化需求，推动了多种通信方案与技术的集成，以满足这些网络的要求。这些方案包括太赫兹通信、协作式非正交多址接入（NOMA）方案以及移动边缘计算（MEC）。太赫兹通信为短距离高数据速率应用提供了丰富的带宽，NOMA方案是实现未来网络目标频谱效率与低延迟需求的有前景技术，而MEC则支持新兴应用中的分布式处理与数据卸载。本文提出了一种能效优化的多用户NOMA辅助协作太赫兹单输入多输出（SIMO）MEC系统方案，使边缘用户通过中心用户将卸载数据上行传输至基站中更丰富的计算资源。为增强所提方案的性能，构建并求解了两个优化问题：第一个问题最小化用户总能耗，第二个问题最大化用户总计算能效（CEE）。在两个问题中，同时优化了NOMA用户配对、基站接收波束成形、传输时间分配及NOMA传输功率分配系数，并考虑每个用户的完全卸载需求及系统预定义延迟约束。研究结果揭示了多用户NOMA辅助协作太赫兹SIMO MEC系统性能与设计的新见解。