Considered the world’s foremost experts on iterative decoding, Thomas J. Richardson and Rüdiger Urbanke have helped optimize data transmission rates for wireless and optical communications and digital information storage. To approach “Shannon’s limit,” which established the maximum rate for communications over a noisy channel, they expanded on low density parity check (LDPC) codes and provided new tools for understanding the complexities of iterative decoding procedures. The result has been reliable data transmission at rates close to channel capacity but with low complexities. Three landmark papers by Drs. Richardson and Urbanke appearing in the February 2001 issue of the IEEE Transactions on Information Theory successfully addressed the obstacles facing the development of capacity-approaching codes. Their work showed that LDPC codes could very closely approach the Shannon limit, showed how to design irregular LDPC codes and provided methods for efficiently encoding LDPC codes. They introduced the density evolution technique, on which practically all subsequent work on LDPC codes is based.
Dr. Urbanke is currently a professor with the Communications and Computer Sciences Department at the École Polytechnique Fédérale de Lausanne in Switzerland.