Ph.D. Research

Progressively Reliable Packet Delivery - "Leaky" ARQ

My doctoral research topic focused on the design of an end-to-end transport layer protocol to support rapid and sufficiently reliable delivery of Web-based images to mobile devices connected to the Internet via a wireless access link.

The protocol provides fast delivery of an initial possibly corrupt version of  each packet, and then leverages off of its ARQ retransmissions to deliver subsequent versions of each packet that are progressively more reliable.  We named the protocol "Leaky ARQ" because it modifies the ARQ retransmission loop such that the receiving end of the protocol can "leak" forward possibly corrupt yet increasingly reliable versions of each packet to the receiving application.

A Web server would employ Leaky ARQ to transport an initial possibly noisy version of an image to the Web browser, which will then display the possibly corrupt image immediately.  The Web server can then rely on Leaky ARQ to deliver progressively more reliable versions of each packet, so that the Web browser can eventually display an image that is free of artifacts.  Leaky ARQ decouples the end user's two objectives of reliability (getting an error-free image) and delay (getting an image quickly).  Leaky ARQ has many other features, or hooks, for adaptive applications, which are described in detail in the paper and thesis available below.

Click here for more detail about the reasoning behind Leaky ARQ and progressively reliable packet delivery.

Papers and Ph.D. Thesis:

The paper "A Progressively Reliable Transport Protocol For Interactive Wireless Multimedia", ACM Multimedia Systems Journal, vol. 7, no. 2, March 1999, pp. 141-156, summarizes many of the ideas in my thesis.   [pdf (293 KB)]

My full Ph.D. thesis "Progressively Reliable Packet Delivery For Interactive Wireless Multimedia", is now available below. [zipped Postscript version (3.5 MB)

An earlier version of my work on progressive reliability appeared in the following paper: R. Han and D.G. Messerschmitt, ``Asymptotically Reliable Transport of Multimedia/Graphics Over Wireless Channels", SPIE Multimedia Computing and Networking, Proc. SPIE, Vol. 2667, pp. 99-110, January 1996, San Jose, CA.  [pdf (183 KB)].

Last updated: September 13, 1999