From: Jonathan Naylor (limsa.bovao@mae.es)
Date: Wed Mar 10 2004 - 19:50:53 EET
Hi Thomas
I hope things are well with you.
>Soft decision decoding of block codes is hard to do efficiently. In
>fact I don't
>know any algorithm that does it efficiently. That's why normally a
>convolutional code
>is used as inner code 8-)
I agree entirely, that would be my choice also. Concatenated codes is a
much nicer way to do it BUT I am trying to clone JT65 and Joe Taylor
used a soft decision RS decoder to gain 2dB advantage over a standard RS
decoder, he didn't use a Convolution code as a front end. Unfortunately
he signed a NDA to get the code from someone so I can't just use what he
uses. I am not very happy about it.
I'm not too worried about efficiency since the decoding will not be done
in real-time so if it takes many seconds to decode a message, then so be
it. So if you have access to an inefficient soft decision RS decoder, I
would still be interested :-)
I could use a standard RS decoder but I would lose 2dB which would make
my decoder somewhat ineffective on an EME path compared to his.
>Tom
Jonathan
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