Eric,
there are many options. One is a (31,16) BCH code
with 3 bits error correction capability.
It would have been nice to have a generic BCH encoder/decoder
block that can also do mixed error correction/detection...
In the absence of that, we can always use a rate 1/2 convolutional code
off the self.
Achilleas
Eric Blossom wrote:
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
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