Performance evaluation of QoS technique for supporting multiple contact point haptic device interactions

Improving the interaction experience between humans and computers is a major research challenge and one of the most promising new modes of Human Computer Interaction (HCI) is via haptic devices which provide users with the sense of touch while interacting with computer systems. Two or more users may interact with each other and exchange the sense of touch by using Distributed Haptic Virtual Environments (DHVEs). In these systems, the quality of the touch sense is degraded by impairments in packet switched networks (packet delay, loss and jitter). Recent research has established that the Quality of Service (QoS) required to support haptic traffic is significantly different from that required to support conventional real-time traffic such as voice or video. To date most research into distributed haptics has considered only haptic devices with a single point of contact, however the enhanced experience provided by multiple contact point devices means that future DHVEs are likely to employ these devices. The research presented here extends this work to consider the more complex traffic produced by haptic devices with multiple contact points, whenever interacting remotely with virtual environments. Such devices produce a rich mixture of different traffic streams that are interdependent but also characterised by the interactions of the individual users. This study describes experiments designed to evaluate the performance of multi-contact point haptic devices and demonstrates that the use of a traffic engineering approach, Class Based Weighted Fair Queue (CBWFQ), can be used to improve the QoS experienced by this type of haptic traffic.