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[ax25-layer2] ECC vs. FCS

Samuel A. Falvo II sam.falvo at gmail.com
Fri Aug 4 00:52:06 UTC 2006


On 8/3/06, Glenn Thomas <glennt at charter.net> wrote:
> I don't think so. The syndrome bits are part and parcel of the whole
> package. If you just send the syndrome bits, and some of them don't
> match the original syndrome bits, you can't tell which version is
> correct! ...oh, if both copies are identical as received, you haven't
> transferred any additional information. You have burned some
> bandwidth without getting anything for it.

Knowing that the syndrome bits are sent in a separate packet, what
difference is there if I send the syndrome frame immediately adjacent
to the intended data frame, or 30 seconds after?  The passage of time
does nothing to the original bits of the data frame as received at the
receiver.

> The utility of ECC is something that can be established or refuted
> for the Amateur radio environment by the statistical study I proposed
> in an earlier posting.

I believe Phil Karn already has performed these studies, and agreed
that FEC is the way to go.  I cannot seem to locate those documents,
however, so take that as a possibly failed recollection for the time
being.

-- 
Samuel A. Falvo II




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