Re: [Discuss-gnuradio] Problem in framer_sink

[Eric Blossom]

On Sun, Mar 11, 2007 at 02:59:58PM -0700, Johnathan Corgan wrote:
> Achilleas Anastasopoulos wrote:
> 
> > Regarding protecting the length field, a rate 1/2 linear block code
> > can always be used.
> > 
> > The way it is now it is a repetition code which offers little
> > protection.
> 
> As-is there is no FEC in in the digital packet code anyway.  When we add
> that, we'll likely do it for the complete header and payload at the same
> time.

I don't think so.  We need to be able to reliably determine the length
of the packet (which we get from the header), to find the end of the
packet.

I think Achilleas' suggestion of a rate 1/2 block code for the header is
the way to go.  Achilleas, do you have a specific suggestion?  Golay
would protect 12-bits.  Any off-the-shelf code that does a good job on
16-bits of payload?

Also, splitting the PHY layer framing from the handling of the payload
CRC / FEC allows upper layers to be independent of the low-level
framing mechanism.

Eric