mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2025-11-03 21:40:52 -05:00
88 lines
3.2 KiB
HTML
88 lines
3.2 KiB
HTML
|
<HTML><HEAD>
|
||
|
|
|
||
|
|
<TITLE> Examples of LDPC Program Usage </TITLE>
|
||
|
|
|
||
|
|
</HEAD><BODY>
|
||
|
|
|
||
|
|
|
||
|
|
<H1> Examples of LDPC Program Usage </H1>
|
||
|
|
|
||
|
|
<P>Below, are some command files containing examples of the use of
|
||
|
|
the <A HREF="progs.html">LDPC programs</A>, together with the output I
|
||
|
|
obtained for these examples. Output on other machines might
|
||
|
|
conceivably be slightly different, due to different round-off errors.
|
||
|
|
The <A HREF="run-examples"><TT>run-examples</TT></A> script runs all the example
|
||
|
|
scripts and compares their output with the outputs that I obtained (on
|
||
|
|
a Pentium machine).
|
||
|
|
|
||
|
|
<P><A HREF="ex-ham7b">ex-ham7b</A>,
|
||
|
|
output in <A HREF="ex-ham7b-out">ex-ham7b-out</A>
|
||
|
|
<BLOCKQUOTE>
|
||
|
|
A (7,4) Hamming code used with a BSC.
|
||
|
|
Demonstrates encoding of random messages and decoding to minimize
|
||
|
|
bit error rate by exhaustive enumeration.
|
||
|
|
</BLOCKQUOTE>
|
||
|
|
|
||
|
|
<P><A HREF="ex-ham7a">ex-ham7a</A>,
|
||
|
|
output in <A HREF="ex-ham7a-out">ex-ham7a-out</A>
|
||
|
|
<BLOCKQUOTE>
|
||
|
|
A (7,4) Hamming code used with an AWGN channel. Tested using zero messages.
|
||
|
|
Decoded by exhaustive enumeration to minimize either block or bit error rate,
|
||
|
|
and by probability propagation.
|
||
|
|
</BLOCKQUOTE>
|
||
|
|
|
||
|
|
<P><A HREF="ex-dep">ex-dep</A>,
|
||
|
|
output in <A HREF="ex-dep-out">ex-dep-out</A>
|
||
|
|
<BLOCKQUOTE>
|
||
|
|
Examples of how parity check matrices with linearly dependent rows (ie,
|
||
|
|
redundant parity checks) are handled. This is probably not of
|
||
|
|
great interest to most users.
|
||
|
|
</BLOCKQUOTE>
|
||
|
|
|
||
|
|
<P><A HREF="ex-ldpc-encode">ex-ldpc-encode</A>,
|
||
|
|
output in <A HREF="ex-ldpc-encode-out">ex-ldpc-encode-out</A>
|
||
|
|
<BLOCKQUOTE>
|
||
|
|
Encodes messages with an LDPC code using sparse, dense, and mixed
|
||
|
|
representations of the generator matrix.
|
||
|
|
</BLOCKQUOTE>
|
||
|
|
|
||
|
|
<P><A HREF="ex-ldpc36-1000a">ex-ldpc36-1000a</A>,
|
||
|
|
output in <A HREF="ex-ldpc36-1000a-out">ex-ldpc36-1000a-out</A>
|
||
|
|
<BLOCKQUOTE>
|
||
|
|
A (2000,1000) LDPC code with 3 checks per bit and 6 bits per check.
|
||
|
|
Three encoding methods are tried out, and the code is
|
||
|
|
tested on an AWGN channel at various noise levels, using random messages.
|
||
|
|
</BLOCKQUOTE>
|
||
|
|
|
||
|
|
<P><A HREF="ex-ldpc36-5000a">ex-ldpc36-5000a</A>,
|
||
|
|
output in <A HREF="ex-ldpc36-5000a-out">ex-ldpc36-5000a-out</A>
|
||
|
|
<BLOCKQUOTE>
|
||
|
|
A (10000,5000) LDPC code with 3 checks per bit and 6 bits per check.
|
||
|
|
Tested on an AWGN channel at various noise levels, using random messages.
|
||
|
|
Pipes are used to avoid creating lots of files.
|
||
|
|
</BLOCKQUOTE>
|
||
|
|
|
||
|
|
<P><A HREF="ex-ldpcvar-5000a">ex-ldpcvar-5000a</A>,
|
||
|
|
output in <A HREF="ex-ldpcvar-5000a-out">ex-ldpcvar-5000a-out</A>
|
||
|
|
<BLOCKQUOTE>
|
||
|
|
A (10000,5000) LDPC code with the number of checks per bit varying from 2 to 7.
|
||
|
|
Tested on an AWGN channel at various noise levels, using random messages.
|
||
|
|
Pipes are used to avoid creating lots of files. Performance is better than
|
||
|
|
for the code above in which the number of checks is the same for all bits.
|
||
|
|
</BLOCKQUOTE>
|
||
|
|
|
||
|
|
<P><A HREF="ex-wrong-model">ex-wrong-model</A>,
|
||
|
|
output in <A HREF="ex-wrong-model-out">ex-wrong-model-out</A>
|
||
|
|
<BLOCKQUOTE>
|
||
|
|
Tests what happens when messages are decoded using the wrong noise
|
||
|
|
model, including using the right type of model but with the wrong
|
||
|
|
noise level, and using the wrong type of model (ie, using an AWLN model
|
||
|
|
for messages transmitted through an AWGN channel, or vice versa).
|
||
|
|
</BLOCKQUOTE>
|
||
|
|
|
||
|
|
<HR>
|
||
|
|
|
||
|
|
<A HREF="index.html">Back to index for LDPC software</A>
|
||
|
|
|
||
|
|
</BODY></HTML>
|