## 3 AR/VR Hardware and Software Requirements
### Edge Computing and the Tactile Internet  
With the proliferation of the IoT for many sensing devices in AR/VR applications, these devices suffer from limitations regarding the data, resources for computing, and communications [87]. It has been estimated by Cisco that the data generated by machines, IoT devices, and people are likely to exceed by 500 zettabytes (ZB) [88]. Edge cloud computing is considered a solution to overcome the above-mentioned challenges. This also reduces latency for end users due to the capability of providing computational and storage resources at the edge of the radio access network (RAN). In order to satisfy the VR/AR ultra-low latency requirements, there should be a suitable reduction in communication distance, which can be achieved by multi-access mobile edge computing (MEC) by bringing the applications closer to the end users [89; 90]. MEC acts as a key enabler of 5G technology due to its main functionalities of computation and storage at edge hosts located close to the radio access network nodes (e.g., gNodeBs in 5G) in a distributed manner. Due to the distributed nature of the network, MEC enables low-latency services with the requirement of a very low and bounded delay between the end user devices and the server hosting the application. Due to the challenges faced by the stringent requirements of AR/VR technologies, the 5G-enabled Tactile Internet (TI) with computation-intensive tasks on edge computing servers is considered as the most-reliable solution to obtain ultra-reliable and sub-millisecond latency communication [91].  
The TI is an innovative tool used for AR/VR applications comprising sensors, actuators, robotics, computation components, and dedicated hardware (e.g., wearable devices) to empower tactile and haptic (e.g., touch, visual, and auditory) feedback in Internet-based applications [92]. The TI is assumed to be the next evolutionary phase of the Internet of Things (IoT) utilizing machine-to-machine (M2M) and human-to-machine (H2M) interactions to incorporate a wide range of application scenarios in the industrial, eHealthcare, education, and entertainment sectors. With the usage of 5G communications, the TI has turned into an evolutionary technology for the IoT and Society 5.0 by providing delay mitigation and enabling real-time interaction with haptic data over the Internet to address complex issues in our current society [93]. Three different layers of the TI, namely the master, network, and slave layers, should be analyzed carefully while integrating 5G with the TI for ultra-reliable low-latency applications. The master layer has an important role in the conversion of the human input or haptic feedback (from a communication perspective) into tactile data by using a human-system integration present at the layer. Then, the HSI transmits the tactile data created by suitable tactile encoding techniques over the controlled domain via the network layer. The controlled domain provides all the haptic feedback signals including audio/visual feedback signals to the master layer connected over the network domain via a two-way communication link. With its integration with 5G, low-latency communication is achieved by incurring a round-trip time (RTT) of less than 5 ms, which will support haptic communication [94].