## 1 Introduction  
Smart grids are expected to be intelligent, dynamic, secure and flexible [1]. In this sense, information and communication technology (ICT) plays a vital role in this concept [2], where a fast and reliable communication infrastructure is critical. With ICTs, power systems will be controlled and monitored, enabling their operators to detect and to react to internal and external grid changes [3]. Microgrids are small active distribution power systems with their own distributed energy resources (DERs) [4], loads [5] and electrical storage units [6]. They may operate connected to the main grid or islanded from it when necessary, during a fault or disturbance [7]. In islanded mode, different levels of control have been proposed to describe grid operation [8]. The primary control is responsible for the natural response of the generators, executed by the droop method. Frequency and voltage are restored at the secondary control. Moreover, the tertiary control is responsible for optimizing the load flow. All these three levels of control are implemented at the microgrid central controller (MGCC). The MGCC performs the secondary control during the system operation, being responsible for managing all communication between intelligent electronic devices (IEDs), monitoring and controlling the bi-directional flow of data from smart meters, sensors, feeders, actuators, and loads in the whole environment [9]. The microgrid management actions rely on a robust communication infrastructure [10], and the dependence increases proportionally to the grid smartness due to the number of connected devices into the microgrid [11]. These devices need to intercommunicate, exchange data and report the microgrid status instantly to the MGCC to act and react due to any adversity [12]. Therefore, a flexible communication infrastructure is going to be necessary to support the massive number of connected devices [13]. Cellular communications systems are a potential candidate to provide the strict requirements for smart microgrid applications [14]. They are robust, secure, support massive device connection and require low infrastructure investments. The wireless infrastructure is mainly built by three components [15]: the core network, the access network and the last-mile network. Users communicate with the access network by a wireless link, in particular, base station units to provide connectivity and the access network connects through the core network to provide an Internet connection. In a wireless access network, a critical issue is the average power consumed to maintain a reliable and robust active network, which has been growing up to 15-20 percent a year [16]. An enormous amount of power consumption in an access network is associated with the consumption of base stations (BS), which accounts for 60-80% of the total power consumption [17]. A significant concern is to improve energy efficiency in communication networks [18] to decrease the impact on system operation. Much attention has been given to the effect of communication systems in noncritical environments [19] and urban smart grid environments [20]. As a way to add more intelligence to the microgrid, the multi-agent system has to be integrated with the distribution network to improve microgrid control during outage operation [21]. In [22], the importance of an intelligent distributed autonomous power systems to manage microgrids during lack of energy is shown. However, the work proposed in [23] presents an alternative design of the previous work, and a fully integrated architecture between all agents in the system to achieve grid intelligence, adding capabilities to the entire system, has been proposed. Nevertheless, just a few investigations have addressed the issue of energy efficient communications in islanded microgrid environments where distributed energy resources work together with batteries to supply the grid for the maximum available time.