Investigating Quality of Service Issues for Distributed Haptic Virtual Environments in IP Networks

The effective transmission of traffic involving the sense of touch (haptics) presents a significant challenge to the current Internet architecture. It is now accepted that the Quality of Service (QoS) needed to support haptic feedback in networks will be significantly different from that used to support conventional real-time traffic such as voice or video, primarily because this traffic originates from a different human sense and has specific tolerances to delay and loss of the force and position that is reflected back to the user. Haptic applications therefore require a stringent QoS from the network for successful interaction in Distributed Virtual Environments (DVEs). Network impairments such as time delay, jitter and packet loss each have different (and severe) impacts on the user´s haptic experience for haptic interaction. Network delay reduces the fidelity when touching a virtual object due to reduction of force response. Jitter and packet loss can cause abrupt force feedback. All of these can cause system instability in the haptic feedback loop between the user and the virtual environment being rendered. This paper describes some of the issues and challenges that are presented whenever remote haptic interactions with virtual environments are considered, and identifies a number of QoS parameters and techniques to compensate for the network impairments in the network and in the end applications, that can be used to improve performance of such systems.