# Review of Communication Technologies for Electric Vehicle Charging Management and Coordination
###### Abstract
In addition, the development of vehicular dynamic wireless power transfer (DWPT) solutions reveals opportunities for wireless energy exchange between moving vehicle, using mobile energy disseminators (MEDs) as movable energy supply units [18; 19], as well as using direct energy transfer from one passenger vehicle to another (vehicle-to-vehicle (V2V) energy transfer) [20; 21]. The integration of the aforementioned EV charging solutions within the city infrastructure is expected to increase EV adoption by ensuring ubiquitous charge availability and improving the convenience levels for EV owners. This contributes to the establishment of an internet of electric vehicles (IoEV) in which EVs are considered as intelligent entities equipped with multiple on-board sensors and actuators, and can communicate and exchange information securely with one another and with the surrounding infrastructure to enable driving and charging coordination, energy management, and traffic optimization [22; 23]. A smart city infrastructure model demonstrating the integration of different EV charging infrastructures in an IoEV is shown in Figure 1.  
In order to enable effective EV charging coordination and management in an IoEV, effective communication strategies need to be implemented, in which a communication link is established between the EV and the charging infrastructure, i.e., vehicle-to-infrastructure (V2I) and infrastructure-to-vehicle (I2V) communication, as well as between neighboring EVs, i.e., vehicle-to-vehicle (V2V) communication. This is because the lack of communication and coordination between EVs within the city infrastructure is expected to cause congestion, inefficient energy distribution, imbalanced loads, and other adverse effects on the operation of the grid. In contrast, smart charging coordination, involving massive data exchange between the different network entities, is expected to solve these issues by utilizing advanced information and communication technologies (ICT) to build a communication infrastructure that enables load balancing, charge scheduling, and reliable authentication and billing services [24; 25]. Different communication link characteristics are essential to address the requirements of the different charging modes. For example, a static charging scenario requires a high security and high reliability communication link to ensure accurate information exchange between the EV and the EVSE, but can be tolerant to a certain delay since the EV is stationary [26; 27]. Dynamic wireless charging, on the other hand, is intolerant to delay and requires a very low latency and high-reliability, two-way communication link to enable effective communication with the charging infrastructure during the vehicle's mobility on the road [28]. The capacity of the communication link is another important characteristic that depends on the volume of the information to be exchanged. The nature of this information is also a factor as it may include higher priority messages, such as safety messages and emergency calls, and lower priority messages including information on the EV's current state of charge (SoC), desired charging power level, etc. In general, the required communication systems for enabling effective EV wireless charging must provide support for different data types and priorities and must offer the ability to allocate different quality levels to each while ensuring interoperability [24]. Furthermore, the mobility of interconnected vehicles is expected to cause fast channel fading and other channel impairments due to the high speeds of the vehicles. For time-critical applications, such as dynamic wireless charging of EVs, the proposed communication system needs to handle two-way communications at a high speed in real-time with ultra-low latency while enabling handovers between the different communication domains and the different elements of the charging infrastructure.