State of the art in rate-1/4 codes for Gaussian channels
The figure shows the performance of various codes
with rate 1/4 over the Gaussian
Channel. From left to right:
- Irregular low density parity check code over GF(8),
blocklength 48000 bits (Davey and MacKay, 1999);
- JPL turbo code (JPL, 1996)
blocklength 65536;
- Regular LDPC over GF(16), blocklength 24448
bits (Davey and MacKay, 1998);
- Irregular binary LDPC, blocklength 16000 bits (Davey, 1999);
- M.G. Luby, M. Mitzenmacher, M.A. Shokrollahi and
D.A. Spielman's (1998)
irregular binary LDPC,
blocklength 64000 bits;
- JPL's code for Galileo: a concatenated code based on
constraint length 15, rate 1/4 convolutional code (in 1992, this
was the best known code of rate 1/4); blocklength about 64,000 bits;
- Regular
binary LDPC [similar to the one shown in
Demonstration 2]:
blocklength 40000 bits (MacKay, 1999).
The Shannon limit
is at about -0.79 dB.
Back to Demonstration number 2: rate 1/4 code, Gaussian channel
(c) David J.C. MacKay
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