Characterising Distributed Haptic Virtual Environment Network Traffic Flows

Abstract

The effective transmission of haptic data in Distributed Haptic Virtual Environment (DHVEs) is a new research area which presents a number of challenges to the underlying network. The transmission of reflected force in these applications has the potential to change the way humans interact with machines and communicate with each other. The future Internet will have to carry multiple DHVE type traffic and it is now established that the best effort service offered by current IP networks is insufficient to meet the needs of these type of applications, which require specific Quality of Service (QoS) from network. The aim of the work presented here is to characterise the traffic generated by multiple DHVE network connections. The approach taken is to develop a simulation model of DHVE traffic based on empirical measurements. Both synchronous and asynchronous real world DHVE traffic is analyzed, quantified and imported into a network simulation. Probability Density Function (PDF) models are subsequently derived for each type of traffic in the DHVE system. The results show the network simulation model compares favourably with the physical network, and can be used to generate a scalable haptic network model where multiple DHVE connections may be examined.

Simulation and Performance Evaluation of a Distributed Haptic Virtual Environment Supported by the CyberMed Framework

“…The maximum value of end-toend delay was 0.0175 seconds (17.5 milliseconds) of retardation for tutoring collaboration, what is totally acceptable according to delay's requirements for supporting telehaptics applications that should be less than 50 milliseconds according to the parameters basis presented on Table I. Thus, for collaborations of tutoring with up to ten users, it can be said that CybCollaboration runs with almost no environment degradations, over a hybrid network, once the maximum packet loss percentage was 1,2 % and the endto-end delay was 17,5 ms, which is totally acceptable by the QoS parameters of the telehaptic applications presented by the literature previously mentioned [5,6,7]. …”

“…One of these works conclusions reveals that for the user perception experiment, a good sense of touch requires a delay of less than 5 ms [6]. In [7], the authors performed several experiments to investigate the requirements for DHVEs which runs under best-effort services.…”

“…It can also handle the three basic structures of networking communication which are: unicasting, where the message is addressed to just one destination host; broadcasting, where the message is sent through the network to all connected hosts; and finally multicasting, where the messages are sent to different groups of destination hosts, giving the possibility of using flexible communication services, among other advantages. Considering the requirements for supporting collaboration with haptic feedback, some research has shown that DHVEs requires high levels of graphic and haptic update rates, which are at around 30 Hz and 1KHz respectively [6]. The collaboration provided nowadays by the collaboration module, named CybCollaboration, is based on the UDP transport protocol in association with a peer-to-peer architecture, which provides a reasonable transmission rate for haptic data.…”

“…The chosen simulation tool also enables the use of Probability Density Functions (PDFs) for producing and setting up different kinds of data traffic patterns such as those common in multimedia systems, as well as typical VR applications. In a DHVE context, the experiment presented in [6] shows one of the OM simulator capabilities by developing a PDF to characterize the data flows generated by a haptic device. In the CybCollaboration' simulation experiment, it was created a node responsible for generating haptic data traffic and for processing all packets according to CybCollaboration's protocol.…”

A Study to Support Haptic Collaboration with Real Time Force Feedback over Wireless Networks

“…The future Internet will have to carry a wide range of applications, and many of these will incorporate new types of traffic. There has been recent interest in the transmission of multimodal information over the Internet [1], and in particular the transmission of haptic 1 data [2] [3]. Currently all interactions that occur between ourselves and communications networks especially the Internet involve only two senses (aural and visual).…”