Editing Turbo code (section)

==History==
The fundamental patent application for turbo codes was filed on 23 April 1991. The patent application lists [[Claude Berrou]] as the sole inventor of turbo codes. The patent filing resulted in several patents including [https://patents.google.com/patent/US5446747 US Patent 5,446,747], which expired 29 August 2013.

The first public paper on turbo codes was "''Near Shannon Limit Error-correcting Coding and Decoding: Turbo-codes''".<ref>{{Citation|chapter-url=https://www.researchgate.net/publication/3604275 |first1=Claude |first2=Alain |first3=Punya |last1=Berrou |author1-link=Claude Berrou|last2=Glavieux |author2-link=Alain Glavieux |last3=Thitimajshima |author3-link=Punya Thitimajshima |chapter=Near Shannon Limit Error – Correcting |accessdate=11 February 2010 |date=1993 |volume=2 |pages=1064–70 |doi=10.1109/ICC.1993.397441 |title=Proceedings of IEEE International Communications Conference|s2cid=17770377 }}</ref> This paper was published 1993 in the Proceedings of IEEE International Communications Conference. The 1993 paper was formed from three separate submissions that were combined due to space constraints. The merger caused the paper to list three authors: Berrou, [[Alain Glavieux|Glavieux]], and [[Punya Thitimajshima|Thitimajshima]] (from Télécom Bretagne, former [[École Nationale Supérieure des Télécommunications de Bretagne|ENST Bretagne]], France). However, it is clear from the original patent filing that Berrou is the sole inventor of turbo codes and that the other authors of the paper contributed material other than the core concepts.{{Synthesis inline|date=February 2021|sure=yes}}

Turbo codes were so revolutionary at the time of their introduction that many experts in the field of coding did not believe the reported results. When the performance was confirmed a small revolution in the world of coding took place that led to the investigation of many other types of iterative signal processing.<ref>{{cite journal |author=Erico Guizzo |title=CLOSING IN ON THE PERFECT CODE |journal=IEEE Spectrum |date=Mar 1, 2004 |url=https://spectrum.ieee.org/closing-in-on-the-perfect-code|archive-url=https://archive.today/20230423205925/https://spectrum.ieee.org/closing-in-on-the-perfect-code|url-status=dead|archive-date=23 April 2023}}</ref>

The first class of turbo code was the parallel concatenated convolutional code (PCCC). Since the introduction of the original parallel turbo codes in 1993, many other classes of turbo code have been discovered, including [[serial concatenated convolutional codes]] and [[repeat-accumulate code]]s. Iterative turbo decoding methods have also been applied to more conventional FEC systems, including Reed–Solomon corrected convolutional codes, although these systems are too complex for practical implementations of iterative decoders. Turbo equalization also flowed from the concept of turbo coding.

In addition to turbo codes, Berrou also invented recursive systematic convolutional (RSC) codes, which are used in the example implementation of turbo codes described in the patent. Turbo codes that use RSC codes seem to perform better than turbo codes that do not use RSC codes.

Prior to turbo codes, the best constructions were serial [[concatenated code]]s based on an outer [[Reed–Solomon error correction]] code combined with an inner [[Viterbi algorithm|Viterbi-decoded]] short constraint length [[convolutional code]], also known as RSV codes.

In a later paper, Berrou gave credit to the intuition of "G. Battail, [[Joachim Hagenauer|J. Hagenauer]] and P. Hoeher, who, in the late 80s, highlighted the interest of probabilistic processing." He adds "[[Robert G. Gallager|R. Gallager]] and M. Tanner had already imagined coding and decoding techniques whose general principles are closely related," although the necessary calculations were impractical at that time.<ref>{{Citation|first=Claude|last=Berrou|title=The ten-year-old turbo codes are entering into service|location=Bretagne, France|accessdate=11 February 2010|url=https://www.researchgate.net/publication/3199004}}</ref>