Hybrid and Forward Error Correction Transmission Techniques for Unreliable Transport of 3D Geometry
Zhihua Chen and J. Fritz Barnes and Bobby Bodenheimer
Abstract
The continual improvement in computer performance
together with the prevalence of high-speed network
connections having high throughput and moderate latencies
enables the deployment of multimedia applications, such as
collaborative virtual environments, over wide area networks.
These applications can serve as simulated environments in
scenarios such as emergency response training to catastrophic
disasters, military training, and entertainment. Many of these
systems use 3D graphics for display and may be required to
distribute geometric models on demand between participants.
Progressive meshes provide an attractive mechanism for such
distribution. Previous uses of progressive meshes have sent
data using reliable protocols (TCP). However, such protocols
have disadvantages in on-demand settings, in that they: (1)
use flow control, which limits performance in wide area networks;
(2) add additional bandwidth when there is loss; (3)
treat all loss as an indication of congestion; and (4) require
feature-rich multicast support, which is not always available.
In this paper, we modify progressive mesh models to allow
reconstruction even in the event of packet loss. We use these
modifications in two transmission schemes, a hybrid transmission
that uses TCP and UDP to send packets and a forward
error-correcting transmission scheme that uses redundancy
to decode the information sent. We assess the performance
of these transmission schemes when deployed on network
testbeds that simulate wide-area and wireless characteristics.
Bobby Bodenheimer 