[bit1]

Raptor codes are powerful, but one has to be careful with them, as they are heavily patent encumbered by Qualcomm according to Wikipedia[1]:

"Raptor codes are heavily covered with patents in various jurisdictions. For the specific instances specified in RFCs, statements by patent owners may or may not provide some leeway, depending among other things on whether the device carrying the implementation also implements a "wide-area wireless" specification."

So I encourage people who otherwise work with Error-Correcting codes to tread lightly when considering implementing Raptor and RaptorQ codes.

[1] https://en.wikipedia.org/wiki/Raptor_code

[haneefmubarak]

Huh. That's slightly disappointing.

Do you know of any other fountain codes more powerful than the LT code described in the article, that are not particularly patent encumbered? This seems like a really interesting area, but from reading around a bit, it seems like part of the issue is that because all of the research is so recent, you end up stepping on someone or other's IP.

[mpoloton]

You can have a look at Tornado codes[1]. These codes are also based on LT codes and their patent seems to be no longer in effect.

For a completely open and free alternative for application-level forward erasure correction (AL-FEC) codes, checkout OpenFEC[2].

1 - https://en.wikipedia.org/wiki/Tornado_code 2 - http://openfec.org

[mpoloton]

Online Codes (https://en.wikipedia.org/wiki/Online_codes) are very similar to Raptor codes for rateless erasure coding. The construction consists of an inner an outer code. However unlike RaptorQ, they are not optimized for an entire range of block lengths.