## 1 Introduction  
Virtual reality (VR) is considered as one type of the most widely-announced applications of the fifth-generation cellular system (5G) [1, 2, 3]. In addition, many applications and market sectors are expected to be introduced in many areas of life [4]. Furthermore, augmented reality (AR) is considered as a new technology that enables the augmentation of real objects in the surrounding environments such as perceptual information extracted from multiple sensory modes containing haptic, visual and auditory sensors [5, 6]. In addition to that, the recent developments and advances in sensory manufacturing, AR devices (e.g., Epson Moverio and Google Glass) and AR toolkits (e.g., ARKit) lead to developing a wide range of AR/VR applications in various domains [7, 8], which are considered to be ultra-low latency applications and required an end-to-end latency in terms of 5 ms [9, 10, 11]. However, designing a reliable AR/VR system that achieves the required latency constraints and other required quality of service (QoS) requirements is a challenge. This is due to the long distance between the application server and the end users, which leads to increase the network latency and thus, affects the user experience [12]. To address these issues, mobile edge computing (MEC), software-defined networking (SDN) and network function virtualization (NFV) have been promised as new technologies that have received much attention lately and can provide the AR/VR applications with an ultra-low latency [13, 14, 15, 16]. MEC is a recent paradigm that brings the computing capabilities at the edge of the radio access network (RAN), near to end-users and thus, reduces the communication latency. This paradigm turns the centralized huge data centers to distributed small edge servers and thus, moves from the centralization to the decentralization of computing resources [17]. Introducing edge-cloud servers in the way between the AR end-user and the application server achieves many benefits that include the reduction of communication latency. SDN and Network softwarization are another key paradigm and recent communication technology which provide the required flexibility and open the way for network innovation by separating data and control plans. In addition, SDN deployment for AR networks provides the required reliability and flexibility. Furthermore, SDN also can manage the distributed MEC servers and control the communication with the application server. Based on 5G technology, data can be transferred with high speed and low latency, where society will rapidly enter the new era of smart cities and the Internet of things (IoT). Industry stakeholders have identified several potential use cases for 5G networks, and ITU-R has identified three important categories for these use cases: Enhanced Mobile Broadband (eMBB)--enhanced broadband indoor and outdoor, corporate collaboration, augmented and virtual reality; massive machine-type communications (mMTC)--IoT, smart agriculture, smart cities, energy monitoring, smart home, remote monitoring; and ultra-reliable low-latency communications (URLLC)--autonomous vehicles, smart grids, remote patient monitoring and telemedicine, production automation. According to wireless operators, eMBB will be the primary scenario for using 5G in the early stages of network deployment. Based on eMBB, densely populated areas will be covered by high-speed mobile broadband, users will have access to high-speed streaming data on-demand on home devices, screens and mobile devices, and we will see services for corporate collaboration development. Some operators are also considering eMBB as the solution in areas where there are not enough copper cable connections or fiber-optic connections to the living quarters. 5G technology is also expected to contribute to the development of smart cities and IoT by deploying a large number of low-power sensor networks in urban and rural areas.