2 things. 1. Wow that's cool. 2. Is this technology not patented by Digital Fountain? (now Qualcomm?) I remember when I first heard of fountain codecs, I thought it was science fiction based on the description :-). Dave On Tue, Oct 19, 2010 at 8:00 PM, Tom Hawkins wrote:

This library [1] implements a fountain code [2]. Fountain codes are forward error correction codes for erasure channels [3]. A fountain code encodes a message into an infinite stream of packets -- transmitters generate message packets at random, on-the-fly. To reconstruct the message, receivers simply need to capture enough packets for the decoding process. As a rateless code, fountain codes automatically adapt to varying channel conditions.

Some of the more interesting applications of fountain codes include unsynchronized data broadcast and distributed download. For example, a multiple number of devices can transmitting content to multiple receivers without any coordination. Because packets are generated at random, receivers increase their bandwidth simply by listening to more transmitters. Note that receivers can also start generating packets and forwarding the message on even before they have decoded the complete message.

This library provides a packet generator and a decoder for one of the first known fountain codes: LT codes [4]. It also includes a test function to experiment with message lengths, and encoding degrees -- it runs a simulation to determine the number of packets needed to decode a message.

-Tom

[1] http://hackage.haskell.org/package/fountain [2] http://en.wikipedia.org/wiki/Fountain_code [3] http://en.wikipedia.org/wiki/Binary_erasure_channel [4] http://en.wikipedia.org/wiki/LT_codes _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe