Empirical Study of VBR Traffic Smoothing in Wireless Environment

Abstract

This work presents the result of the empirical study on the effect of VBR smoothing in broadband wireless network. Traffic smoothing of VBR stream has been the subjects of intense research during past several years. While preceding algorithms successfully remove burstiness in the underlying process, these works do not address how the respective smoothing algorithm can effectively improve the QoS in practical environment. We developed MPEG-4 streaming system and instrument the client terminal which is handheld mobile device. We examine the effect of smoothing over the packet loss behavior and empirical QoS under various different system settings. We use the rate variability as optimization criterion in generating the packet transmission schedule. We find that smoothing with small size buffer(10 Kbyte) brings a significant improvement on packet loss ratio and greatly enhances the QoS perceived by the end user. Via adopting smoothing technique in transporting multimedia traffic, we are able to increase the acceptable quality frame rate by 50%.

This work is funded by KOSEF through Statistical Research Center for Complex System at Seoul National University.