## 1 Introduction
Islanded microgrid operation relies on the communication network to interact with the energy management system (EMS), which must be able to control and manage all available power sources and loads. Several energy management systems have been proposed in the literature [24]. The primary objective of this scheme is to increase the electricity supply time during an outage event. However, little attention has been paid to the communication infrastructure power consumption in microgrid operation. In [25], a wireless network infrastructure is integrated with the electrical system. The communication system is properly considered as loads, and the results show the wireless power consumption influence in the microgrid survival time. The difference in the supply time duration for a microgrid with and without taking into account communication load is remarkable. However, in [25], the entire communication network is considered a priority energy load, always transmitting and receiving data, assuming the power grid as an unlimited source of energy. Thus, it consumes an enormous amount of power. In addition, in [25], as a way to save BS power consumption, soft sleep modes have been implemented in the microgrid energy management system. The sleep mode is a technique where the BSs can be turned off during periods or put to sleep to reduce power consumption [26; 27]. However, energy saving schemes are not considered in [25], and the communication loads are always active, even though, sleep modes consumes less power. In this article, a new approach is proposed aiming to optimize and maximize the microgrid resiliency to achieve maximum energy efficiency. A hybrid methodology has been implemented in the EMS management control. Communications loads are no longer considered a priority load and different sleep mode depths are applied according to the microgrid operation status. During the islanded operation, the whole communication system can be turned off, or, just a few base station devices can be deactivated, decreasing energy consumption and achieving maximum energy efficiency. Nevertheless, the network deactivation will affect the communication system reliability [28]. Reliability is related to the system latency, which is considered the ability to react to a system change quickly. For instance, if the communication system is completely turned off and an unexpected outage event occurs, the EMS decision will take longer to be executed due to high latency. It will take some time to activate the communication system and take the desired action, increasing the reaction time, and consequently increasing latency and decreasing system reliability. This compromised solution establishes a trade-off between maximum energy consumption, system reliability, and smart applications availability. To further investigate the impact of turning off BS devices, a continuous-time Markov chain (CTMC) model analyzes the microgrid communication network reliability between changes in the microgrid operation status. In addition, an adapted model of the IEEE 34 bus node is used to model the problem and to access the performance of the proposed solution. The paper is organized as follows. Section 2 presents the critical communications issues in microgrids. In Section 3, the energy management system under communication constraints is presented. Section 4 discusses the trade-off between communication power consumption and reliability in islanded microgrid. In Section 5, the proposed methodology is presented, simulated and validated. Finally, Section 6 discusses the conclusions.