WWW Browsing using a Transcoding Proxy
Carleton University, Ontario, Canada. December 2000.

With advances in wireless networking technology and portable information appliances, a new paradigm of computing, called mobile or nomadic computing, has generated much attention in recent years. This new platform will make it possible for users who carry portable devices to browse WWW information regardless of their physical location or movement behavior. Such a new environment, however, faces many technical challenges such as limited wireless bandwidth and high error rate. In addition, mobile devices widely differ with respect to display size, color depth, processing power, battery life, and the ability to handle different data formats. Since images usually present the highest rate of WWW traffic, image transcoding could greatly reduce web page retrieval latency and match both the device and channel capabilities. This thesis presents a proxy transcoding process that enhances image transmission to a variety of mobile hosts. The central idea in our work is to place a transcoding proxy between the generic WWW servers and the diversity of client devices in order to adapt to a greatly changing bandwidth on the proxy-client link and to manage the heterogeneity of small-screened mobile devices. The proxy utilizes transcoding functions based on the available bandwidth and the device characteristics to achieve the smallest file size and acceptable quality.