基于NOMA的多用户协作MEC卸载方案

A multi⁃user cooperative MEC offloading scheme based on NOMA

移动边缘计算(Mobile Edge Computing,MEC)在网络边缘为用户提供计算服务,有效降低了数据传输和处理时延,成为第五代移动通信系统(the 5th Generation Mobile Communication System,5G)低时延通信的关键技术。如何优化设计卸载策略以保证低时延、低能耗和高可靠通信是MEC面临的一个极具挑战性的任务。为此,文中针对频谱和能量双受限的多用户多任务MEC系统场景,提出可最小化系统能耗的多用户任务非正交多址(Non⁃Orthogonal Multiple Access,NOMA)协作中继卸载计算方案。考虑多用户协作中继场景并允许多任务基于NOMA实现并行卸载传输,在时延约束下建立多用户任务卸载计算能耗最小化问题;利用拉格朗日对偶法求解该问题,得到最优的基于中继的任务卸载传输方案和用户功率分配方案。仿真结果表明,所提方案能够有效降低MEC系统的多任务卸载计算能耗。

Mobile edge computing(MEC) provides computing services for users at the edge of the network. It can effectively reduce data transmission and processing delays, and become one of the key technologies for the low-latency communication of the 5th Generation Mobile Communication System(5G). Optimized offloading strategies are critical to the low latency, low energy consumption and highly reliable communication for MEC. In this regard, this paper proposes a multi-user cooperative offloading scheme based on non-orthogonal multiple access(NOMA) that can minimize the system energy consumption for the multi-user multi-task MEC system with limited spectrum and energy. Given the multi-user cooperative relay scenario and multi-tasks’ parallel offload transmission based on NOMA, an energy consumption minimization problem for the multi-user multi-task offloading computing is established under the delay constraint. The Lagrangian dual method is used to solve this problem, and the optimal relay-based task offloading transmission scheme and the user power allocation scheme are obtained. The simulation results show that the proposed scheme can effectively reduce the energy consumption of the multi-task offloading in the MEC system.