The improvement of the energy efficiency and the reduction of the latency are two of the main goals of the next generation of Radio Access Networks (RANs). In order to achieve the latter, Multi-access Edge Computing (MEC) is emerging as a promising solution: it consists of the placement of computing and storage servers, directly at each Base Station (BS) of these networks. For the RAN energy efficiency, the dynamic activation of the BSs is considered an effective approach. In this paper, the caching feature of the MEC paradigm is considered in a portion of an heterogeneous RAN, powered by a renewable energy generator system, energy batteries and the power grid, where micro cell BSs are deactivated in case of renewable energy shortage. The performance of the caching in the RAN is analysed through simulations for different traffic characteristics, as well as for different capacity of the caches and different spread of it. New user association policies are proposed, in order to totally exploit the MEC technology and reduce the network energy consumption. Simulation results reveal that, thanks to this technology and the proposed methodologies, the experienced delay and the energy consumption drop, respectively, up to 60% and 40%.

能源效率的提高和等待时间的减少是下一代无线接入网（RAN）的两个主要目标。为了实现后者，多访问边缘计算（MEC）成为一种有前途的解决方案：它由直接在这些网络的每个基站（BS）上放置计算和存储服务器组成。对于RAN能量效率，BS的动态激活被认为是有效的方法。在本文中，在异构RAN的一部分中考虑了MEC范例的缓存功能，该部分由可再生能源发电系统，能源电池和电网供电，在可再生能源短缺的情况下，微蜂窝基站将被停用。通过针对不同流量特征的仿真来分析RAN中的缓存性能，以及不同的缓存容量和不同的传播速度。为了充分利用MEC技术并降低网络能耗，提出了新的用户关联策略。仿真结果表明，由于这项技术和所提出的方法，经历的延迟和能耗下降分别高达60％和40％。