Irregular Repeat Accumulate (IRA) Codes build on top of the ideas of RA codes. IRA replaces the outer code in RA code with a Low Density Generator Matrix code.<ref>{{cite web |first=Hui |last=Jin, |first2=Aamod |last2=Khandekar & |first3=Robert |last3=McEliece,"|title=Irregular Repeat-Accumulate Codes."[ |date=2000 |publisher=Department of Electrical Engineering, California Institute of Technology |url=http://www.mceliece.caltech.edu/publications/Brest00.pdf]}}</ref> IRA codes first repeats information bits different times, and then accumulates subsets of these repeated bits to generate parity bits. The irregular degree profile on the information nodes, together with the degree profile on the check nodes, can be designed using density evolution.
Systematic IRA codes are considered a form of [[LDPC]] code. Litigation over whether the DVB-S2 LDPC code is a form of IRA code is ongoing.<ref>[http://www.law360.com/articles/622198/hughes-satellite-codes-spark-caltech-patent-suit 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.{{cn|date=August 2021}}
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== References ==
* {{cite conference |first=D. |last=Divsalar, |first2=H. |last2=Jin, and |first3=R.J. |last3=McEliece."|title=Coding theorems for ‘turbo-like’ codes."''Proc.|book-title=Proceedings of the 36thannual Allerton Conf.Conference on Communication,Controlcontrol and Computing,Allerton,|date=September Illinois'',1998 Sept.|pages=201–210 1998,|volume=36 pp|publisher=University Of Illinois |url=https://www. 201–210researchgate.net/profile/Dariush-Divsalar/publication/243768674_Coding_Theorems_for_Turbo-Like_Codes/links/53e3cc5c0cf2fb74870dbbc1/Coding-Theorems-for-Turbo-Like-Codes.pdf}}
