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2004 World Technology Awards Winners & Finalists

Prof. Claude Berrou and Prof. Alain Glavieux

Please describe the work that you are doing that you consider to be the most innovative and of the greatest likely long-term significance.

Turbo codes

The foundations of information theory and modern digital communications were laid by Claude Elwood Shannon (Bell Labs, USA), during the years 1947-1949. In particular, Shannon determined the important theoretical limit concerning the foreseeable quality of digital transmissions by means of an error-correcting code, that remained to be found.

The theoretical result determined by Shannon represented a major scientific challenge for thousands of researchers and engineers because the economic stakes are high. Improving the correcting power of a code means, with the same quality of received information (for example, not more than one erroneous bit out of 10,000 received, for digital telephony), enabling a transmission system to work in the most severe conditions. It is then possible to reduce the size of the antennas, the size of the solar panels, or the weight of the power batteries. In space systems (satellites, probes and so on), savings can be calculated in tens of millions of dollars, since the weight of the equipment and the power of the launcher can thus be considerably reduced. In mobile cellular telephone systems, improving the code also allows the operator to raise the number of potential users in the cell or to save the cellphone’s power supply.

Until the invention of turbo codes at the beginning of the 90’s, the best error-correcting codes still remained far from the ideal performance. The introduction into information theory of a very widespread concept in electronics, feedback (hence the prefix "turbo", by analogy with the principle of exhaust gas recirculation in turbocharged engines), enabled the gap between theory and practice to be bridged. The invention of turbo codes, through different innovatory concepts such as iterative probabilistic decoding and extrinsic information, greatly marked the scientific community (see, for example "Closing in on the perfect code", by Erico Guizzo, IEEE Spectrum, pp. 36-42, March 2004). These concepts were extended to functions other than error-correcting coding, in the communication chain. Today, for example, we speak of turbo-equalization, turbo-detection and turbo-synchronization.

Turbo codes were rapidly adopted by the CCSDS (Consultative Committee for Space Data Systems), the standardization committee for international space agencies (NASA, ESA, NASDA etc.). The first European mission using turbo codes was the SMART-1 probe launched at the end of 2003. Then, other standardization committees soon integrated turbo codes into the standards of 3rd generation communication systems: UMTS in Europe, and CDMA2000 in the United States and Asia. Other systems using turbo codes (INMARSAT, EUTELSAT, DVB-RCS, DVB-RCT, BRAN, IEEE 802.16, magnetic recording, etc.) have already been standardized or are currently being specified.

For the invention of turbo codes and the extension of the "turbo" principle, their inventors*, Claude Berrou and Alain Glavieux, both Professors at the Ecole Nationale Supérieure des Télécommunications de Bretagne (ENST Bretagne), France, have been awarded a certain number of national and international distinctions, among which:

- 1997 : French Médaille Ampère awarded by the Société des Electriciens et Electroniciens (SEE) medal. - 1998 : Golden Jubilee Award for Technological Innovation (IEEE Information Theory Society). - 2003 : Richard W. Hamming Medal (IEEE), "for the invention of turbo codes, which have revolutionized digital communications". - 2003 : French Grand Prix France Télécom awarded by the Académie des Sciences.

* NOTE: Punya Thitimajshima, who passed away on May 9, 2006, is also often credited as the co-inventor of turbocoding.  For his contributions, he also received the 1998 IEEE (Information Theory) Golden Jubilee Award for Technological Innovation. 

Today, hundreds of researchers and engineers throughout the world are working to take advantage of the error-correction power of turbo codes or to find new applications based on the "turbo" principle.

Brief Biography

Claude Berrou was born in Penmarc'h, France, in 1951. In 1978, he joined the Ecole Nationale Supérieure des Télécommunications de Bretagne (ENST Bretagne), where he is currently a Professor in the Electronics Department. In the early 80's, he started up the training and research activities in VLSI technology and design, to meet the growing demand from industry for microelectronics engineers. Some years later, Prof. Claude Berrou took an active interest in the field of algorithm/silicon interaction for digital communications. In collaboration with Prof. Alain Glavieux, he introduced the concept of probabilistic feedback into error correcting decoders and developed a new family of quasi-optimal error correction codes, that he nicknamed turbo codes. He also pioneered the extension of the turbo principle to joint detection and decoding processing, known today as turbo-detection and turbo-equalization. His current research topics, besides algorithm/silicon interaction, are electronics and digital communications at large, error correction codes, turbo codes and iterative processing, soft-in/soft-out (probabilistic) decoders, etc. He is the author and/or co-author of 8 registered patents and about 60 publications in the field of digital communications and electronics. He has received several distinctions with Prof. Glavieux, amongst which the 1997 French SEE Médaille Ampère medal, the 1998 IEEE (Information Theory) Golden Jubilee Award for Technological Innovation, the 2003 IEEE Richard W. Hamming medal and the 2003 French Grand Prix France Télécom de l'Académie des sciences award.

Alain Glavieux, was born in 1949 in Paris, France, and graduated from the Ecole Nationale Supérieure des Télécommunications (ENST) in 1978. He was granted the French National Authorization to supervise research in 1994. In 1979 he became Associate Professor at the Ecole Nationale Supérieure des Télécommunications de Bretagne (ENST Bretagne), where he lectured in signal processing and communication theory and set up a digital communications research group. He was appointed Professor in 1989, and became Head of the Signals and Communications Department in 1994, his teaching and research activities being in the field of communications and information coding. In 1998, he took charge of ENST Bretagne’s Relations with Industry and, in 2002, became Head of the CNRS laboratory “Algorithmic and Hardware Processing of Information Communications and of Knowledge”. In 2003, he was appointed assistant director of ENST Bretagne.

His research activities focus on communications over radio-mobile and underwater acoustic channels as well as information coding. In collaboration with Prof. Claude Berrou, he invented turbo codes in the 90’s and helped extend the “turbo” effect to the communication chain. He is the author and/or co-author of 4 registered patents in the field of “turbo” technologies, and around 30 publications and a book on digital communications. He received jointly with Prof. Berrou the IEEE (Information Theory) Golden Jubilee Award for Technological Innovation in 1998, and the 2003 IEEE Richard W. Hamming medal and the 2003 French Grand Prix France Télécom de l'Académie des sciences award.