Professor, ECE (Deceased)
Information theory specializing in error-correcting codes for data transmission and storage.
Professor Vardy is a leading expert in coding theory. With coding and decoding of error-correcting codes taking place in a plethora of devices, from satellites to cell phones and from computer drives to CDs, his work has widespread implications. His research is leading to a better understanding of the uses and limitations of error-correcting codes in encoding data for transmission and storage. Soft-decision decoders capture more information from an encoded signal than conventional hard-decision decoders, and thereby enable reliable communication at lower signal power. Vardy has co-developed an efficient algebraic soft-decision decoder for Reed-Solomon codes, which are the most popular class of error-correcting codes in use today. It has long been known that random codes achieve channel capacity. However, Vardy proved that computing the distance of a random code, which is necessary for its evaluation, is an intractable problem. He has also helped explain mathematically why iterative codes (such as turbo codes and LDPC codes) come close to achieving capacity.
Alexander Vardy came to the Jacobs School in 1998 from the faculty of the University of Illinois, Urbana-Champaign. Before that, he worked in the private sector, including a stint as a visiting scientist at the IBM Almaden Research Center. Among other honors, he is a Fellow of the IEEE and a past Editor-in-Chief of the IEEE Transactions on Information Theory. He received his Ph.D. in Electrical Engineering in 1991 from Tel Aviv University. Vardy is a recipient of a David and Lucile Packard Fellowship and an NSF CAREER award.