Re: Forward error correction - experiment


"k7udr" <bhhoyer@...>
 

The problem with FX.25 is that in order to be backwards compatible they bundle the FEC bits at the end of the packet. As no-one to my knowledge has actually deployed FX25, I prefer a clean sheet approach so we can look at not only FEC, but other choices of modulation and encoding as well.

Backwards compatibility can be assured by connecting on either AX25 or D-STAR, then negotiating upwards amongst capable radios.

After we have the UDR shipping, we'll be starting a new independent group, sponsored by TAPR, to investigate open methodologies for advancing amateur radio.

Exciting times ahead!
Bryan K7UDR

--- In UniversalDigitalRadio@..., "zl2wrw" <ross@...> wrote:



--- In UniversalDigitalRadio@..., "marshalldennyai4cm" <MarshallDenny@> wrote:

Testing with variable levels of FEC added to an otherwise standard ax.25 protocol.

That sounds very much like the FX.25 protocol:
http://en.wikipedia.org/wiki/FX.25_Forward_Error_Correction

It's even backwards compatable with plain old non-FEC AX.25 equipment. Though it does not rectify some of the other historical defects of the AX.25 protocol that are due to the adapting of wireline X.25 to a wireless physical layer...


73 ZL2WRW
Ross Whenmouth

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