In the traditional mobile edge computing (MEC) system, the availability of MEC services is greatly limited for the edge users of the cell due to serious signal attenuation and inter-cell interference. User-centric MEC (UC-MEC) can be seen as a promising solution to address this issue. In UC-MEC, each user is served by a dedicated access point (AP) cluster enabled with MEC capability instead of a single MEC server, however, at the expense of more energy consumption and greater privacy risks. To achieve efficient and reliable resource utilization with user-centric services, we propose an energy efficient blockchain-enabled UC-MEC system where blockchain operations and resource optimization are jointly performed. Firstly, we design a resource-aware, reliable, replicated, redundant, and fault-tolerant (R-RAFT) consensus mechanism to implement secure and reliable resource trading. Then, an optimization framework based on alternating direction method of multipliers (ADMM) is proposed to minimize the total energy consumed by wireless transmission, consensus and task computing, where APs clustering, computing resource allocation and bandwidth allocation are jointly considered. Simulation results show superiority of the proposed UC-MEC system over reference schemes, at most 33.96% reduction in the total delay and 48.77% reduction in the total energy consumption.

翻译：在传统移动边缘计算（MEC）系统中，由于严重的信号衰减和小区间干扰，小区边缘用户的MEC服务可用性受到极大限制。用户中心MEC（UC-MEC）被视为解决该问题的有前景方案。在UC-MEC中，每个用户由配备MEC能力的专属接入点（AP）集群提供服务，而非单一MEC服务器，但这以更高的能耗和更大的隐私风险为代价。为实现用户中心服务下的高效可靠资源利用，我们提出一种联合执行区块链操作与资源优化的节能区块链赋能UC-MEC系统。首先，我们设计一种资源感知、可靠、复制、冗余且容错的共识机制（R-RAFT），以实施安全可靠的资源交易。随后，基于交替方向乘子法（ADMM）提出优化框架，联合考虑AP聚类、计算资源分配与带宽分配，最小化由无线传输、共识达成及任务计算产生的总能耗。仿真结果表明，所提UC-MEC系统在性能上优于参考方案，总延迟最多降低33.96%，总能耗最多降低48.77%。