# Model Mediation to Overcome Light Limitations--Toward a Secure Tactile Internet System
## 1 Introduction
The internet protocol security (IPSec) represents a sufficient framework for security issues associated with most of traditional communication applications, while for haptic communication applications and other applications (e.g., augmented reality (AR) and virtual reality (VR)), new security frameworks should be introduced since existing frameworks cannot be used [36, 37]. This is because the implementations of current security methods for these systems affect the communication latency constraints by introducing much delay. Thus, security issues and the required security levels of tactile Internet applications should be considered for each kind or group of applications with the consideration of end-to-end latency constraints required by the system to achieve acceptable level of user experience [38]. The main challenge among these design constraints is the ultra-low latency, which represents the main obstacle toward system development and realization. Tactile Internet required an end-to-end latency of 1 ms, which means that all delays from the data transmission at the transmitter until the feedback reception at the transmitter should be at maximum of 1 ms to allow an acceptable experience [39]. The network domain of the tactile Internet systems should be designed in a proper way to achieve the requirements of the tactile Internet and as the 1 ms latency is a main requirement, the communication network should deploy new technologies to achieve this. 5G cellular systems will be proper but still far from 1 ms end-to-end latency [40]. In this work, we mainly consider the challenge of 1 ms and the associated security issues. In [41], we developed a multi-level edge computing framework for the tactile Internet  
1 ms end-to-end latency of the tactile Internet system; whatever the distances between the transmitter and the receiver. Tactile Internet is expected to support and introduce many applications in different fields as previously introduced, however haptic communications will be the main applications run over the tactile Internet [37]. Thus, our main concern, in this work, is the haptic communication over the tactile Internet. This work mainly considers the 1 ms latency constraint with consideration to light limitations and associated security issues. Furthermore, it introduces a literature review of model mediated systems that can be used to overcome light limitations and realize the tactile Internet system. Section 2 discusses the main features of the haptic communications as it represents the main application that will run over the tactile Internet. In Section 3, the reasons for the 1 ms end-to-end latency design constraint and light limitations for tactile Internet realization are discussed. Section 4 reviews the model mediated systems introduced for bilateral teleoperated systems and analyze them. Furthermore, methods for environmental modeling and main challenges associated with the design of model mediated system are introduced. Section 5 discusses the main security issues associated with the tactile Internet system and how the introduction of model mediation can solve these issues. In Section 6, we discuss how the model mediated can be used for the tactile Internet system with the introduction of artificial intelligent algorithms to overcome the problem of 1 ms latency and the light limitations, and to achieve the security levels for different tactile Internet applications. Finally, the work is concluded in Section 7.