Irregular Repeat Accumulate (IRA) Codes are a derivative form of repeat accumulate (RA) codes where the repetition performed inon the input bits is not the sameequal for all bits.<ref>Hui Jin, Aamod Khandekar & Robert McEliece, "Irregular Repeat-Accumulate Codes."[http://www.mceliece.caltech.edu/publications/Brest00.pdf]</ref> For example, some bits may be repeated three (3) times during coding, while other bits may be repeated eight (8) times.
Systematic IRA codecodes are considered a form of [[LDPC]] codescode. TheLitigation claimover thatwhether the DVB-S2 standard implements an LDPC code that is a form of an IRA code is currently under litigationongoing.<ref>Hughes Satellite Codes Spark Caltech Patent Suit.[http://www.law360.com/articles/622198/hughes-satellite-codes-spark-caltech-patent-suit]</ref> US patents 7,116,710; 7,421,032; 7,916,781; and 8,284,833 are at issue.
