Re: Forward error correction - experiment


Marshall Denny <MarshallDenny@...>
 

I will have a look at FX.25.

But, with the flexibility that the UDR will give us.  Lets keep all good ideas on the table until we have a good reason to remove it.  

The potential of FEC is not will known in the ham community.

For example, compare the potential for operating in noisy conditions between psk31 and olivia.  
Olivia will operate below the noise floor.
I have worked Olivia on 80m with thunderstorms in the region with 50 over S9 static crashes with 100% copy.

If well done, this could allow very poor signals to get through at low speed.
And, also allow 56k packet under conditions that would not work otherwise.

Respectfully,
Marshall
AI4CM 

On Wed, Mar 27, 2013 at 4:18 AM, zl2wrw <ross@...> wrote:
 



--- In UniversalDigitalRadio@..., "marshalldennyai4cm" 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




--
Respectfully,
W. Marshall Denny II
Software Development Engineer
206 734 9242 cell

For if you altogether hold your peace at this time,
then shall relief and deliverance arise to the Jews from another place;
but you and your father's house shall be destroyed:
and who knows whether you are come to the kingdom for such a time as this?  Esther 4:14 KJV

Join main@nw-digital-radio.groups.io to automatically receive all group messages.