These FEC systems (that respond well to trying to "guess" uncorrected errors during the decoding process) are what the satellite data industry call "turbo" codes. They've been around for a few years now, and I think they've been incorporated into the recent DVB-S2 standard which should be freely available from the ETSI's website. They typically add several dBs improvement to the Eb/No performance of a link "for free"...
Graham Bryce G7LGI -----Original Message----- From: Kristoff Bonne [mailto:[email protected]] Sent: 10 October 2012 22:22 To: [email protected] Subject: Re: [Freetel-codec2] FEC Hi Steve, On 08-10-12 18:12, Steve Strobel wrote: > I just stumbled across another idea related to FEC... If the bit > decoding process in the receiving modem records a "confidence" value > for each bit it decodes and the FEC indicates that there are too many > errors to correct, it would be reasonable to try flipping combinations > of the bits in which the receiver was the least confident until the > FEC was able to correct any remaining errors. Of course it might make > the FEC happy by finding a different message than was originally sent, > a false positive. But since the bit flipping would happen on the bits > that were most likely to be wrong, it should have a reasonable chance > of getting the original message back. It would also take extra > processing time, so would probably need to be an optional feature not > available on smaller embedded platforms. > The original article about this can be found here: > <http://tinyurl.com/8ver97l>. I already had read something like that. (not that I am really such an expert in FEC now; just starting to learn about it). The nice thing about this is that this only involved the decoding process. So from "encoding" or "specifications" point of view; nothing changes. This is -if I see it correct- focused on finding better ways to determine exactly -if there are biterrors- exactly what bits are wrong. It would be nice to implement this in the FEC but I fear this will have to be done by somebody who knows more about math then myself. :-) > Steve 73 Kristoff - ON1ARF ---------------------------------------------------------------------------- -- Don't let slow site performance ruin your business. Deploy New Relic APM Deploy New Relic app performance management and know exactly what is happening inside your Ruby, Python, PHP, Java, and .NET app Try New Relic at no cost today and get our sweet Data Nerd shirt too! http://p.sf.net/sfu/newrelic-dev2dev _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2 ------------------------------------------------------------------------------ Don't let slow site performance ruin your business. Deploy New Relic APM Deploy New Relic app performance management and know exactly what is happening inside your Ruby, Python, PHP, Java, and .NET app Try New Relic at no cost today and get our sweet Data Nerd shirt too! http://p.sf.net/sfu/newrelic-dev2dev _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
