In this paper, a Rate-Splitting Multiple Access (RSMA) scheme is proposed to assist a Mobile Edge Computing (MEC) system where local computation tasks from two users are offloaded to the MEC server, facilitated by uplink RSMA for processing. The efficiency of the MEC service is hence primarily influenced by the RSMA-aided task offloading phase and the subsequent task computation phase, where reliable and low-latency communication is required. For this practical consideration, short-packet communication in the Finite Blocklength (FBL) regime is introduced. In this context, we propose a novel uplink RSMA-aided MEC framework and derive the overall Successful Computation Probability (SCP) with FBL consideration. To maximize the SCP of our proposed RSMA-aided MEC, we strategically optimize: (1) the task offloading factor which determines the number of tasks to be offloaded and processed by the MEC server; (2) the transmit power allocation between different RSMA streams; and (3) the task-splitting factor which decides how many tasks are allocated to splitting streams, while adhering to FBL constraints. To address the strong coupling between these variables in the SCP expression, we apply the Alternative Optimization method, which formulates tractable subproblems to optimize each variable iteratively. The resultant non-convex subproblems are then tackled by Successive Convex Approximation. Numerical results demonstrate that applying uplink RSMA in the MEC system with FBL constraints can not only improve the SCP performance but also provide lower latency in comparison to conventional transmission scheme such as Non-orthogonal Multiple Access (NOMA).

翻译：本文提出了一种速率分割多址接入方案，用以辅助一个移动边缘计算系统。在该系统中，两个用户的本地计算任务通过上行链路RSMA卸载至MEC服务器进行处理。因此，MEC服务的效率主要受RSMA辅助的任务卸载阶段及后续的任务计算阶段影响，这两个阶段均需要可靠且低延迟的通信。基于这一实际考量，我们引入了有限块长度（FBL）机制下的短包通信。在此背景下，我们提出了一种新颖的上行链路RSMA辅助MEC框架，并在考虑FBL的情况下推导了整体成功计算概率。为了最大化所提出的RSMA辅助MEC的SCP，我们策略性地优化了以下变量：(1) 任务卸载因子，其决定了卸载至MEC服务器处理的任务数量；(2) 不同RSMA流之间的发射功率分配；(3) 任务分割因子，其决定了分配给分割流的任务数量，同时需满足FBL约束。为了解决SCP表达式中这些变量之间的强耦合问题，我们采用交替优化方法，该方法通过构建易于处理的子问题来迭代优化每个变量。由此产生的非凸子问题则通过逐次凸逼近方法求解。数值结果表明，在具有FBL约束的MEC系统中应用上行链路RSMA，与非正交多址接入等传统传输方案相比，不仅能提升SCP性能，还能提供更低的延迟。