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Add routines for a (240,74) code. Hardwire decoder for wspr messages, for the time being.

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This commit is contained in:
Steven Franke 2020-06-30 13:29:32 -05:00
parent d916f315d3
commit e8bb7e74bc
10 changed files with 1342 additions and 6 deletions
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5
CMakeLists.txt
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@ -596,15 +596,18 @@ set (wsjt_FSRCS
lib/wqencode.f90
lib/wspr_downsample.f90
lib/zplot9.f90
lib/fst240/bpdecode240_101.f90
lib/fst240/decode240_101.f90
lib/fst240/decode240_74.f90
lib/fst240/encode240_101.f90
lib/fst240/encode240_74.f90
lib/fst240/fst240sim.f90
lib/fst240/gen_fst240wave.f90
lib/fst240/genfst240.f90
lib/fst240/get_fst240_bitmetrics.f90
lib/fst240/ldpcsim240_101.f90
lib/fst240/ldpcsim240_74.f90
lib/fst240/osd240_101.f90
lib/fst240/osd240_74.f90
lib/fst240/get_crc24.f90
)

BIN
lib/.fst240_decode.f90.swp Normal file
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Binary file not shown.

154
lib/fst240/decode240_74.f90 Normal file
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@ -0,0 +1,154 @@
subroutine decode240_74(llr,Keff,maxosd,norder,apmask,message74,cw,ntype,nharderror,dmin)
!
! A hybrid bp/osd decoder for the (240,74) code.
!
! maxosd<0: do bp only
! maxosd=0: do bp and then call osd once with channel llrs
! maxosd>1: do bp and then call osd maxosd times with saved bp outputs
! norder : osd decoding depth
!
integer, parameter:: N=240, K=74, M=N-K
integer*1 cw(N),apmask(N)
integer*1 nxor(N),hdec(N)
integer*1 message74(74),m74(74)
integer nrw(M),ncw
integer Nm(5,M)
integer Mn(3,N) ! 3 checks per bit
integer synd(M)
real tov(3,N)
real toc(5,M)
real tanhtoc(5,M)
real zn(N),zsum(N),zsave(N,3)
real llr(N)
real Tmn
include "ldpc_240_74_parity.f90"
maxiterations=30
nosd=0
if(maxosd.gt.3) maxosd=3
if(maxosd.eq.0) then ! osd with channel llrs
nosd=1
zsave(:,1)=llr
elseif(maxosd.gt.0) then !
nosd=maxosd
elseif(maxosd.lt.0) then ! just bp
nosd=0
endif
toc=0
tov=0
tanhtoc=0
! initialize messages to checks
do j=1,M
do i=1,nrw(j)
toc(i,j)=llr((Nm(i,j)))
enddo
enddo
ncnt=0
nclast=0
zsum=0.0
do iter=0,maxiterations
! Update bit log likelihood ratios (tov=0 in iteration 0).
do i=1,N
if( apmask(i) .ne. 1 ) then
zn(i)=llr(i)+sum(tov(1:ncw,i))
else
zn(i)=llr(i)
endif
enddo
zsum=zsum+zn
if(iter.gt.0 .and. iter.le.maxosd) then
zsave(:,iter)=zsum
endif
! Check to see if we have a codeword (check before we do any iteration).
cw=0
where( zn .gt. 0. ) cw=1
ncheck=0
do i=1,M
synd(i)=sum(cw(Nm(1:nrw(i),i)))
if( mod(synd(i),2) .ne. 0 ) ncheck=ncheck+1
enddo
if( ncheck .eq. 0 ) then ! we have a codeword - if crc is good, return it
m74=0
m74(1:74)=cw(1:74)
call get_crc24(m74,74,nbadcrc)
if(nbadcrc.eq.0) then
message74=cw(1:74)
hdec=0
where(llr .ge. 0) hdec=1
nxor=ieor(hdec,cw)
nharderror=sum(nxor)
dmin=sum(nxor*abs(llr))
ntype=1
return
endif
endif
if( iter.gt.0 ) then ! this code block implements an early stopping criterion
! if( iter.gt.10000 ) then ! this code block implements an early stopping criterion
nd=ncheck-nclast
if( nd .lt. 0 ) then ! # of unsatisfied parity checks decreased
ncnt=0 ! reset counter
else
ncnt=ncnt+1
endif
! write(*,*) iter,ncheck,nd,ncnt
if( ncnt .ge. 5 .and. iter .ge. 10 .and. ncheck .gt. 15) then
nharderror=-1
exit
endif
endif
nclast=ncheck
! Send messages from bits to check nodes
do j=1,M
do i=1,nrw(j)
ibj=Nm(i,j)
toc(i,j)=zn(ibj)
do kk=1,ncw ! subtract off what the bit had received from the check
if( Mn(kk,ibj) .eq. j ) then
toc(i,j)=toc(i,j)-tov(kk,ibj)
endif
enddo
enddo
enddo
! send messages from check nodes to variable nodes
do i=1,M
tanhtoc(1:5,i)=tanh(-toc(1:5,i)/2)
enddo
do j=1,N
do i=1,ncw
ichk=Mn(i,j) ! Mn(:,j) are the checks that include bit j
Tmn=product(tanhtoc(1:nrw(ichk),ichk),mask=Nm(1:nrw(ichk),ichk).ne.j)
call platanh(-Tmn,y)
! y=atanh(-Tmn)
tov(i,j)=2*y
enddo
enddo
enddo ! bp iterations
do i=1,nosd
zn=zsave(:,i)
call osd240_74(zn,Keff,apmask,norder,message74,cw,nharderror,dminosd)
if(nharderror.gt.0) then
hdec=0
where(llr .ge. 0) hdec=1
nxor=ieor(hdec,cw)
dmin=sum(nxor*abs(llr))
ntype=2
return
endif
enddo
ntype=0
nharderror=-1
dminosd=0.0
return
end subroutine decode240_74

46
lib/fst240/encode240_74.f90 Normal file
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@ -0,0 +1,46 @@
subroutine encode240_74(message,codeword)
use, intrinsic :: iso_c_binding
use iso_c_binding, only: c_loc,c_size_t
use crc
integer, parameter:: N=240, K=74, M=N-K
character*24 c24
integer*1 codeword(N)
integer*1 gen(M,K)
integer*1 message(K)
integer*1 pchecks(M)
integer*4 ncrc24
include "ldpc_240_74_generator.f90"
logical first
data first/.true./
save first,gen
if( first ) then ! fill the generator matrix
gen=0
do i=1,M
do j=1,19
read(g(i)(j:j),"(Z1)") istr
ibmax=4
if(j.eq.19) ibmax=2
do jj=1, ibmax
icol=(j-1)*4+jj
if( btest(istr,4-jj) ) gen(i,icol)=1
enddo
enddo
enddo
first=.false.
endif
do i=1,M
nsum=0
do j=1,K
nsum=nsum+message(j)*gen(i,j)
enddo
pchecks(i)=mod(nsum,2)
enddo
codeword(1:K)=message
codeword(K+1:N)=pchecks
return
end subroutine encode240_74

6
lib/fst240/genfst240.f90
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@ -71,7 +71,11 @@ subroutine genfst240(msg0,ichk,msgsent,msgbits,i4tone,iwspr)
entry get_fst240_tones_from_bits(msgbits,i4tone,iwspr)
2 continue
call encode240_101(msgbits,codeword)
if(iwspr.eq.0) then
call encode240_101(msgbits,codeword)
else
call encode240_74(msgbits(1:74),codeword)
endif
! Grayscale mapping:
! bits tone

170
lib/fst240/ldpc_240_74_generator.f90 Normal file
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@ -0,0 +1,170 @@
character*19 g(166)
data g/ &
"de8b3201e3c59f55a14", &
"2e06d352ebc5b74c4fc", &
"2e16d6cf5a725c3244c", &
"84f5587edca6d777de4", &
"e152b1e2b5965093ecc", &
"244b4828a2ccf2b5f58", &
"5fbbaade810e123c730", &
"6b7e92a99a918df3d44", &
"bbcec6a63ab757a7278", &
"f5f3f0b89a21ceccdb0", &
"a248c5f1ec2bc816290", &
"c84bbad839a5fe76d0c", &
"ad724129bbf4c7f4570", &
"91adb56e7623a2575cc", &
"cbe995bdf156df2c9e4", &
"92ff6ea492c08c150e0", &
"c4ddbe5a02f6a933384", &
"d2e9befc131dc483858", &
"68567543d1eebcb080c", &
"21fa61d559f9baf6abc", &
"911c4fbbafc72e3db28", &
"7c0b534af4b7d583d50", &
"12ce371b90ee9dfe72c", &
"15a604148872e251ec4", &
"3a3c9f3eb0e0f96edc0", &
"705919ffb636f96b390", &
"43daaaa8163d6bc2bd4", &
"96e11ea798b74b10e98", &
"811150609c9dee8230c", &
"be713f85ab34380f4b0", &
"5a02c4abaaccb8f24c4", &
"67bdebb8863d04768cc", &
"5a449cd90c3dbdfe844", &
"9c7a54d1c4ef7418b84", &
"cd82fefaaf9cd28cd8c", &
"ca47e847fabb0054a38", &
"f0b30cef6aab9e37f98", &
"d948d912fbcc1708710", &
"cce1a7b355053d98270", &
"4cf227c225a9063dd48", &
"2db92612e9ba1418e24", &
"3d215c04c762c3d6a28", &
"77de65500b5624ceb0c", &
"fd1a1df99ded2fb9d88", &
"2a19392c71438410fb8", &
"a9b486a9d26ed579754", &
"b698d244ac78d97a498", &
"3d7975b74d727a5e704", &
"38094225a2bce0e1940", &
"3d3e58fae40fac342b0", &
"7732e839a066e337714", &
"69356c082b7753a47b0", &
"3e868a55dc403a802ac", &
"a0157a14a6bf7fdbbcc", &
"1ab628e11a7ab4a7c44", &
"9da3a2247d7449052f4", &
"199a8a7b114816b97f4", &
"b1c5cde2542061704cc", &
"432fa8d3a153eafbdc8", &
"c4ece7e400d8a89c448", &
"316ecf74e4b983f007c", &
"6a14fa8e713bb5e8adc", &
"da4b957ded8374e3640", &
"0a804dba7c7e4533300", &
"52c342ed033f86580e0", &
"1667da8d6fcf4272470", &
"da2f7038d550fa88d8c", &
"685bcbab1d9dd2c2a44", &
"4c93008b3156b3636bc", &
"726998d6327ac797c3c", &
"44ece7e400d8a8dc448", &
"01f9add00dfe823a948", &
"dbb95f5ce9e371ad720", &
"fc746ee5c76827a8728", &
"b25408029506467f4b4", &
"9b5c9219e21126b7cf8", &
"39ae9f48ba9d1a24f04", &
"7de2699623eb507f938", &
"b9c6e903ee91dd32934", &
"397510d2c6cb5e81de8", &
"20157a14aebf7fdbbec", &
"067f76ea5817a465980", &
"9248f3cea0869feb994", &
"23cde2678004ebe5f80", &
"5b81fe6848f58e3cfa8", &
"a9099ace96bff092904", &
"4afa4b0802b33215438", &
"f4f740396b030360858", &
"fc613f77a35ee1163b8", &
"1a4dc27d7e8cc835ff4", &
"e9b056f153b39def7ec", &
"b62eb777a2f953c7efc", &
"388ae4de514b62d238c", &
"891529af40e85317160", &
"474f1afeb724dbd2ba8", &
"11d70880fd88fdd307c", &
"29f26a3acb76e6a517c", &
"df3e902ff9cadcf776c", &
"e3c42da8445965c09f0", &
"ce277a6aeccc316dc58", &
"4d7841fb71543abd9b8", &
"e63230d2d465fb44750", &
"b6e11fa798b74b14e98", &
"05f189d37c5616547b4", &
"ebdb51a81d1e883baa8", &
"bf5bc736663bcd53ae0", &
"2f8d1cc0936142c08fc", &
"436b22fc36d917b6928", &
"044b482822ccf2b5f58", &
"37b2e839a066e3b7714", &
"2a9b4b765c581f0c51c", &
"10a7d44cecf8e6628dc", &
"ad95f02df6d5502dd4c", &
"bbd34f8afd63deaf564", &
"cabddfeb01fce632788", &
"66b57babeedd6124114", &
"7813e0454fbd462be8c", &
"b6105ed6f01ea621d04", &
"9f68bbcec679d1c088c", &
"673da96e414fc7a0f40", &
"5568adb935e11084abc", &
"f6dd308de5e5c4f6fb0", &
"3b49e80d40ae596c7b4", &
"a3cde2478004ebe5f80", &
"dd8e4f309e919d5ed94", &
"5a4020d387757d7bc28", &
"64f9e02ae32362a255c", &
"630d5942d392334b0dc", &
"0bd7e9f4229b2dee210", &
"bca549a9467d3a2550c", &
"2fef7b1f578c5e28d04", &
"f35e0fdda1be4b3b35c", &
"69ed575e7cc537d2394", &
"7dfdcfbfd5ef3093680", &
"b3b2921af97f251d328", &
"5622d0fe90363522364", &
"fcd4fc7fa04a69d2ac4", &
"1119ea451502ed9ab34", &
"970ee777ec969a41754", &
"688d14f8afec76783dc", &
"4d0b8a1028578407420", &
"d3d2138d9fa268da3e8", &
"df1bdbff898e006394c", &
"8ac478a916bb0b77684", &
"93881997428e2c17a94", &
"4aa510e746245e90c08", &
"e00cb8543f85a5d58b8", &
"9100d8eb74031073044", &
"38710e4235bd1e4003c", &
"6aef311cac4c4dccfd4", &
"58430f577f51c36b3e0", &
"12082fa5d4268a95b4c", &
"7a7435a0aca071e64d0", &
"cd8250ebadc95de15b0", &
"debad40c852e99d64dc", &
"4e6caa5e7c86efef748", &
"a5d4cbb97e726e3c580", &
"7e3a0a2c73ef8553640", &
"b60bfc2fd2bd8f530dc", &
"32dbef097a5f84b0318", &
"4cc7c1cf434300be380", &
"896840945be8eabf7f0", &
"36c9b10ec694819a0a0", &
"349f46a799ef95a47c8", &
"9bdcd4ce2563e560b74", &
"b19fcd7111a335c52ec"/

423
lib/fst240/ldpc_240_74_parity.f90 Normal file
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@ -0,0 +1,423 @@
data Mn/ &
84, 101, 144, &
10, 14, 138, &
87, 148, 166, &
1, 50, 67, &
2, 53, 74, &
3, 83, 113, &
4, 90, 121, &
5, 63, 128, &
6, 124, 138, &
8, 22, 108, &
11, 28, 159, &
12, 18, 142, &
13, 24, 145, &
15, 131, 149, &
16, 44, 93, &
17, 41, 47, &
19, 37, 129, &
20, 33, 94, &
21, 100, 154, &
23, 71, 141, &
25, 89, 95, &
26, 105, 153, &
27, 36, 58, &
29, 59, 166, &
30, 52, 126, &
31, 61, 77, &
32, 84, 111, &
34, 97, 155, &
38, 98, 127, &
39, 76, 143, &
40, 55, 92, &
42, 147, 158, &
43, 82, 148, &
45, 49, 109, &
46, 70, 86, &
48, 78, 139, &
51, 101, 104, &
54, 63, 96, &
56, 81, 125, &
57, 117, 164, &
60, 75, 107, &
39, 62, 132, &
64, 110, 118, &
24, 65, 146, &
66, 80, 134, &
68, 91, 114, &
69, 123, 162, &
72, 88, 152, &
79, 99, 130, &
85, 112, 124, &
99, 103, 157, &
106, 115, 133, &
116, 120, 140, &
119, 161, 165, &
64, 122, 137, &
34, 89, 135, &
136, 138, 163, &
93, 144, 159, &
35, 130, 150, &
62, 151, 164, &
104, 153, 160, &
1, 106, 166, &
2, 132, 152, &
3, 11, 105, &
4, 18, 160, &
5, 53, 91, &
6, 109, 141, &
7, 111, 113, &
8, 54, 136, &
9, 61, 92, &
10, 40, 101, &
12, 30, 146, &
13, 37, 82, &
14, 29, 95, &
1, 47, 131, &
2, 8, 139, &
3, 58, 130, &
4, 96, 115, &
5, 119, 129, &
6, 60, 148, &
7, 95, 163, &
2, 35, 56, &
9, 67, 79, &
10, 75, 122, &
11, 17, 121, &
12, 137, 145, &
13, 36, 152, &
14, 15, 155, &
15, 134, 143, &
16, 106, 125, &
11, 106, 157, &
18, 99, 118, &
19, 50, 94, &
20, 126, 158, &
21, 41, 135, &
22, 24, 71, &
23, 42, 136, &
22, 109, 161, &
25, 39, 46, &
26, 45, 55, &
27, 77, 82, &
28, 73, 166, &
29, 69, 76, &
30, 108, 150, &
31, 91, 146, &
14, 32, 147, &
33, 35, 107, &
34, 103, 111, &
8, 94, 122, &
13, 70, 151, &
32, 37, 142, &
3, 38, 87, &
25, 51, 92, &
40, 57, 72, &
21, 108, 153, &
23, 26, 142, &
43, 44, 48, &
30, 43, 62, &
7, 45, 154, &
16, 46, 149, &
1, 53, 75, &
33, 44, 160, &
49, 86, 157, &
19, 80, 159, &
51, 116, 138, &
52, 92, 98, &
6, 12, 47, &
54, 83, 101, &
24, 55, 102, &
56, 63, 120, &
17, 57, 82, &
38, 154, 162, &
59, 74, 151, &
53, 144, 164, &
61, 85, 117, &
62, 66, 90, &
48, 113, 145, &
64, 65, 128, &
27, 29, 65, &
58, 63, 134, &
9, 74, 83, &
68, 109, 113, &
41, 61, 69, &
36, 60, 155, &
42, 64, 144, &
40, 90, 130, &
28, 110, 135, &
20, 59, 112, &
70, 110, 124, &
54, 76, 105, &
4, 77, 111, &
78, 104, 143, &
66, 67, 91, &
80, 81, 88, &
50, 101, 132, &
71, 97, 120, &
72, 131, 158, &
84, 133, 141, &
5, 85, 99, &
49, 89, 133, &
87, 132, 140, &
34, 88, 104, &
89, 105, 147, &
6, 76, 102, &
18, 31, 163, &
52, 96, 140, &
93, 102, 165, &
79, 104, 165, &
81, 100, 126, &
95, 121, 152, &
97, 123, 153, &
37, 98, 114, &
8, 91, 155, &
100, 114, 160, &
2, 26, 28, &
93, 116, 150, &
68, 103, 166, &
78, 117, 125, &
86, 107, 127, &
4, 59, 136, &
9, 37, 97, &
7, 30, 75, &
80, 148, 153, &
73, 138, 164, &
10, 39, 103, &
39, 146, 156, &
48, 129, 136, &
5, 17, 51, &
112, 149, 161, &
11, 24, 126, &
1, 70, 78, &
14, 113, 118, &
10, 119, 141, &
13, 33, 105, &
19, 57, 89, &
12, 25, 56, &
16, 18, 54, &
84, 124, 162, &
20, 41, 134, &
15, 45, 82, &
115, 118, 123, &
128, 139, 149, &
127, 156, 159, &
21, 141, 152, &
23, 130, 156, &
3, 160, 164, &
22, 90, 110, &
35, 61, 109, &
31, 87, 158, &
42, 60, 106, &
137, 140, 157, &
27, 114, 124, &
32, 62, 125, &
34, 38, 128, &
40, 123, 139, &
29, 66, 86, &
36, 52, 161, &
43, 63, 133, &
46, 73, 108, &
44, 135, 146, &
47, 115, 127, &
49, 74, 116, &
58, 102, 122, &
55, 85, 132, &
50, 65, 150, &
67, 145, 162, &
53, 71, 77, &
69, 88, 142, &
68, 72, 93, &
9, 64, 95, &
92, 94, 111, &
81, 83, 119, &
98, 143, 163, &
73, 79, 96, &
35, 129, 131, &
99, 100, 151, &
7, 112, 159, &
117, 137, 156, &
120, 147, 154, &
107, 121, 165/
data Nm/ &
4, 62, 75, 121, 191, &
5, 63, 76, 82, 175, &
6, 64, 77, 112, 206, &
7, 65, 78, 151, 180, &
8, 66, 79, 159, 188, &
9, 67, 80, 127, 164, &
68, 81, 119, 182, 237, &
10, 69, 76, 109, 173, &
70, 83, 141, 181, 230, &
2, 71, 84, 185, 193, &
11, 64, 85, 91, 190, &
12, 72, 86, 127, 196, &
13, 73, 87, 110, 194, &
2, 74, 88, 106, 192, &
14, 88, 89, 200, 0, &
15, 90, 120, 197, 0, &
16, 85, 131, 188, 0, &
12, 65, 92, 165, 197, &
17, 93, 124, 195, 0, &
18, 94, 148, 199, 0, &
19, 95, 115, 204, 0, &
10, 96, 98, 207, 0, &
20, 97, 116, 205, 0, &
13, 44, 96, 129, 190, &
21, 99, 113, 196, 0, &
22, 100, 116, 175, 0, &
23, 101, 139, 212, 0, &
11, 102, 147, 175, 0, &
24, 74, 103, 139, 216, &
25, 72, 104, 118, 182, &
26, 105, 165, 209, 0, &
27, 106, 111, 213, 0, &
18, 107, 122, 194, 0, &
28, 56, 108, 162, 214, &
59, 82, 107, 208, 235, &
23, 87, 144, 217, 0, &
17, 73, 111, 172, 181, &
29, 112, 132, 214, 0, &
30, 42, 99, 185, 186, &
31, 71, 114, 146, 215, &
16, 95, 143, 199, 0, &
32, 97, 145, 210, 0, &
33, 117, 118, 218, 0, &
15, 117, 122, 220, 0, &
34, 100, 119, 200, 0, &
35, 99, 120, 219, 0, &
16, 75, 127, 221, 0, &
36, 117, 137, 187, 0, &
34, 123, 160, 222, 0, &
4, 93, 155, 225, 0, &
37, 113, 125, 188, 0, &
25, 126, 166, 217, 0, &
5, 66, 121, 134, 227, &
38, 69, 128, 150, 197, &
31, 100, 129, 224, 0, &
39, 82, 130, 196, 0, &
40, 114, 131, 195, 0, &
23, 77, 140, 223, 0, &
24, 133, 148, 180, 0, &
41, 80, 144, 210, 0, &
26, 70, 135, 143, 208, &
42, 60, 118, 136, 213, &
8, 38, 130, 140, 218, &
43, 55, 138, 145, 230, &
44, 138, 139, 225, 0, &
45, 136, 153, 216, 0, &
4, 83, 153, 226, 0, &
46, 142, 177, 229, 0, &
47, 103, 143, 228, 0, &
35, 110, 149, 191, 0, &
20, 96, 156, 227, 0, &
48, 114, 157, 229, 0, &
102, 184, 219, 234, 0, &
5, 133, 141, 222, 0, &
41, 84, 121, 182, 0, &
30, 103, 150, 164, 0, &
26, 101, 151, 227, 0, &
36, 152, 178, 191, 0, &
49, 83, 168, 234, 0, &
45, 124, 154, 183, 0, &
39, 154, 169, 232, 0, &
33, 73, 101, 131, 200, &
6, 128, 141, 232, 0, &
1, 27, 158, 198, 0, &
50, 135, 159, 224, 0, &
35, 123, 179, 216, 0, &
3, 112, 161, 209, 0, &
48, 154, 162, 228, 0, &
21, 56, 160, 163, 195, &
7, 136, 146, 207, 0, &
46, 66, 105, 153, 173, &
31, 70, 113, 126, 231, &
15, 58, 167, 176, 229, &
18, 93, 109, 231, 0, &
21, 74, 81, 170, 230, &
38, 78, 166, 234, 0, &
28, 156, 171, 181, 0, &
29, 126, 172, 233, 0, &
49, 51, 92, 159, 236, &
19, 169, 174, 236, 0, &
1, 37, 71, 128, 155, &
129, 164, 167, 223, 0, &
51, 108, 177, 185, 0, &
37, 61, 152, 162, 168, &
22, 64, 150, 163, 194, &
52, 62, 90, 91, 210, &
41, 107, 179, 240, 0, &
10, 104, 115, 219, 0, &
34, 67, 98, 142, 208, &
43, 147, 149, 207, 0, &
27, 68, 108, 151, 231, &
50, 148, 189, 237, 0, &
6, 68, 137, 142, 192, &
46, 172, 174, 212, 0, &
52, 78, 201, 221, 0, &
53, 125, 176, 222, 0, &
40, 135, 178, 238, 0, &
43, 92, 192, 201, 0, &
54, 79, 193, 232, 0, &
53, 130, 156, 239, 0, &
7, 85, 170, 240, 0, &
55, 84, 109, 223, 0, &
47, 171, 201, 215, 0, &
9, 50, 149, 198, 212, &
39, 90, 178, 213, 0, &
25, 94, 169, 190, 0, &
29, 179, 203, 221, 0, &
8, 138, 202, 214, 0, &
17, 79, 187, 235, 0, &
49, 59, 77, 146, 205, &
14, 75, 157, 235, 0, &
42, 63, 155, 161, 224, &
52, 158, 160, 218, 0, &
45, 89, 140, 199, 0, &
56, 95, 147, 220, 0, &
57, 69, 97, 180, 187, &
55, 86, 211, 238, 0, &
2, 9, 57, 125, 184, &
36, 76, 202, 215, 0, &
53, 161, 166, 211, 0, &
20, 67, 158, 193, 204, &
12, 111, 116, 228, 0, &
30, 89, 152, 233, 0, &
1, 58, 134, 145, 0, &
13, 86, 137, 226, 0, &
44, 72, 105, 186, 220, &
32, 106, 163, 239, 0, &
3, 33, 80, 183, 0, &
14, 120, 189, 202, 0, &
59, 104, 176, 225, 0, &
60, 110, 133, 236, 0, &
48, 63, 87, 170, 204, &
22, 61, 115, 171, 183, &
19, 119, 132, 239, 0, &
28, 88, 144, 173, 0, &
186, 203, 205, 238, 0, &
51, 91, 123, 211, 0, &
32, 94, 157, 209, 0, &
11, 58, 124, 203, 237, &
61, 65, 122, 174, 206, &
54, 98, 189, 217, 0, &
47, 132, 198, 226, 0, &
57, 81, 165, 233, 0, &
40, 60, 134, 184, 206, &
54, 167, 168, 240, 0, &
3, 24, 62, 102, 177/
data nrw/ &
5,5,5,5,5,5,5,5,5,5,5,5,5,5,4,4,4,5,4,4, &
4,4,4,5,4,4,4,4,5,5,4,4,4,5,5,4,5,4,5,5, &
4,4,4,4,4,4,4,4,4,4,4,4,5,5,4,4,4,4,4,4, &
5,5,5,5,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4, &
4,5,4,4,4,4,4,4,5,4,5,5,5,4,5,4,4,4,5,4, &
5,4,4,5,5,5,4,4,5,4,5,4,5,4,4,4,4,4,4,4, &
4,4,4,5,4,4,4,4,4,5,4,5,4,4,4,5,4,5,4,4, &
5,4,4,4,4,5,4,4,4,4,4,5,5,4,4,4,4,4,5,5, &
4,4,4,5,4,5/
ncw=3

125
lib/fst240/ldpcsim240_74.f90 Normal file
View File

@ -0,0 +1,125 @@
program ldpcsim240_74
! End-to-end test of the (240,74)/crc24 encoder and decoders.
use packjt77
parameter(N=240, K=74, M=N-K)
character*8 arg
character*37 msg0,msg
character*77 c77
character*24 c24
integer*1 msgbits(74)
integer*1 apmask(240)
integer*1 cw(240)
integer*1 codeword(N),message74(74)
integer ncrc24
real rxdata(N),llr(N)
logical first,unpk77_success
data first/.true./
nargs=iargc()
if(nargs.ne.5 .and. nargs.ne.6) then
print*,'Usage: ldpcsim niter ndeep #trials s K [msg]'
print*,'e.g. ldpcsim240_74 20 5 1000 0.85 64 "K9AN K1JT FN20"'
print*,'s : if negative, then value is ignored and sigma is calculated from SNR.'
print*,'niter: is the number of BP iterations.'
print*,'ndeep: -1 is BP only, ndeep>=0 is OSD order'
print*,'K :is the number of message+CRC bits and must be in the range [50,74]'
print*,'WSPR-format message is optional'
return
endif
call getarg(1,arg)
read(arg,*) max_iterations
call getarg(2,arg)
read(arg,*) norder
call getarg(3,arg)
read(arg,*) ntrials
call getarg(4,arg)
read(arg,*) s
call getarg(5,arg)
read(arg,*) Keff
msg0='K9AN K1JT FN20 '
if(nargs.eq.6) call getarg(6,msg0)
call pack77(msg0,i3,n3,c77)
rate=real(Keff)/real(N)
write(*,*) "code rate: ",rate
write(*,*) "niter : ",max_iterations
write(*,*) "norder : ",norder
write(*,*) "s : ",s
write(*,*) "K : ",Keff
msgbits=0
read(c77,'(77i1)') msgbits(1:77)
write(*,*) 'message'
write(*,'(77i1)') msgbits(1:77)
call get_crc24(msgbits,74,ncrc24)
write(c24,'(b24.24)') ncrc24
read(c24,'(24i1)') msgbits(51:74)
write(*,'(24i1)') msgbits(51:74)
write(*,*) 'message with crc24'
write(*,'(74i1)') msgbits(1:74)
call encode240_74(msgbits,codeword)
call init_random_seed()
call sgran()
write(*,*) 'codeword'
write(*,'(77i1,1x,24i1,1x,73i1)') codeword
write(*,*) "Eb/N0 Es/N0 ngood nundetected sigma symbol error rate"
do idb = 8,-3,-1
db=idb/2.0-1.0
sigma=1/sqrt( 2*rate*(10**(db/10.0)) ) ! to make db represent Eb/No
! sigma=1/sqrt( 2*(10**(db/10.0)) ) ! db represents Es/No
ngood=0
nue=0
nberr=0
do itrial=1, ntrials
! Create a realization of a noisy received word
do i=1,N
rxdata(i) = 2.0*codeword(i)-1.0 + sigma*gran()
enddo
nerr=0
do i=1,N
if( rxdata(i)*(2*codeword(i)-1.0) .lt. 0 ) nerr=nerr+1
enddo
nberr=nberr+nerr
rxav=sum(rxdata)/N
rx2av=sum(rxdata*rxdata)/N
rxsig=sqrt(rx2av-rxav*rxav)
rxdata=rxdata/rxsig
if( s .lt. 0 ) then
ss=sigma
else
ss=s
endif
llr=2.0*rxdata/(ss*ss)
apmask=0
dmin=0.0
maxosd=2
call decode240_74(llr, Keff, maxosd, norder, apmask, message74, cw, ntype, nharderror, dmin)
if(nharderror.ge.0) then
n2err=0
do i=1,N
if( cw(i).ne.codeword(i) ) n2err=n2err+1
enddo
if(n2err.eq.0) then
ngood=ngood+1
else
nue=nue+1
endif
endif
enddo
! snr2500=db+10*log10(200.0/116.0/2500.0)
esn0=db+10*log10(rate)
pberr=real(nberr)/(real(ntrials*N))
write(*,"(f4.1,4x,f5.1,1x,i8,1x,i8,8x,f5.2,8x,e10.3)") db,esn0,ngood,nue,ss,pberr
enddo
end program ldpcsim240_74

403
lib/fst240/osd240_74.f90 Normal file
View File

@ -0,0 +1,403 @@
subroutine osd240_74(llr,k,apmask,ndeep,message74,cw,nhardmin,dmin)
!
! An ordered-statistics decoder for the (240,74) code.
! Message payload is 50 bits. Any or all of a 24-bit CRC can be
! used for detecting incorrect codewords. The remaining CRC bits are
! cascaded with the LDPC code for the purpose of improving the
! distance spectrum of the code.
!
! If p1 (0.le.p1.le.24) is the number of CRC24 bits that are
! to be used for bad codeword detection, then the argument k should
! be set to 77+p1.
!
! Valid values for k are in the range [50,74].
!
character*24 c24
integer, parameter:: N=240
integer*1 apmask(N),apmaskr(N)
integer*1, allocatable, save :: gen(:,:)
integer*1, allocatable :: genmrb(:,:),g2(:,:)
integer*1, allocatable :: temp(:),m0(:),me(:),mi(:),misub(:),e2sub(:),e2(:),ui(:)
integer*1, allocatable :: r2pat(:)
integer indices(N),nxor(N)
integer*1 cw(N),ce(N),c0(N),hdec(N)
integer*1, allocatable :: decoded(:)
integer*1 message74(74)
integer indx(N)
real llr(N),rx(N),absrx(N)
logical first,reset
data first/.true./
save first
allocate( genmrb(k,N), g2(N,k) )
allocate( temp(k), m0(k), me(k), mi(k), misub(k), e2sub(N-k), e2(N-k), ui(N-k) )
allocate( r2pat(N-k), decoded(k) )
if( first ) then ! fill the generator matrix
!
! Create generator matrix for partial CRC cascaded with LDPC code.
!
! Let p2=74-k and p1+p2=24.
!
! The last p2 bits of the CRC24 are cascaded with the LDPC code.
!
! The first p1=k-50 CRC24 bits will be used for error detection.
!
allocate( gen(k,N) )
gen=0
do i=1,k
message74=0
message74(i)=1
if(i.le.50) then
call get_crc24(message74,74,ncrc24)
write(c24,'(b24.24)') ncrc24
read(c24,'(24i1)') message74(51:74)
message74(51:k)=0
endif
call encode240_74(message74,cw)
gen(i,:)=cw
enddo
first=.false.
endif
rx=llr
apmaskr=apmask
! Hard decisions on the received word.
hdec=0
where(rx .ge. 0) hdec=1
! Use magnitude of received symbols as a measure of reliability.
absrx=abs(rx)
call indexx(absrx,N,indx)
! Re-order the columns of the generator matrix in order of decreasing reliability.
do i=1,N
genmrb(1:k,i)=gen(1:k,indx(N+1-i))
indices(i)=indx(N+1-i)
enddo
! Do gaussian elimination to create a generator matrix with the most reliable
! received bits in positions 1:k in order of decreasing reliability (more or less).
do id=1,k ! diagonal element indices
do icol=id,k+20 ! The 20 is ad hoc - beware
iflag=0
if( genmrb(id,icol) .eq. 1 ) then
iflag=1
if( icol .ne. id ) then ! reorder column
temp(1:k)=genmrb(1:k,id)
genmrb(1:k,id)=genmrb(1:k,icol)
genmrb(1:k,icol)=temp(1:k)
itmp=indices(id)
indices(id)=indices(icol)
indices(icol)=itmp
endif
do ii=1,k
if( ii .ne. id .and. genmrb(ii,id) .eq. 1 ) then
genmrb(ii,1:N)=ieor(genmrb(ii,1:N),genmrb(id,1:N))
endif
enddo
exit
endif
enddo
enddo
g2=transpose(genmrb)
! The hard decisions for the k MRB bits define the order 0 message, m0.
! Encode m0 using the modified generator matrix to find the "order 0" codeword.
! Flip various combinations of bits in m0 and re-encode to generate a list of
! codewords. Return the member of the list that has the smallest Euclidean
! distance to the received word.
hdec=hdec(indices) ! hard decisions from received symbols
m0=hdec(1:k) ! zero'th order message
absrx=absrx(indices)
rx=rx(indices)
apmaskr=apmaskr(indices)
call mrbencode74(m0,c0,g2,N,k)
nxor=ieor(c0,hdec)
nhardmin=sum(nxor)
dmin=sum(nxor*absrx)
cw=c0
ntotal=0
nrejected=0
npre1=0
npre2=0
if(ndeep.eq.0) goto 998 ! norder=0
if(ndeep.gt.6) ndeep=6
if( ndeep.eq. 1) then
nord=1
npre1=0
npre2=0
nt=40
ntheta=12
elseif(ndeep.eq.2) then
nord=1
npre1=1
npre2=0
nt=40
ntheta=12
elseif(ndeep.eq.3) then
nord=1
npre1=1
npre2=1
nt=40
ntheta=12
ntau=14
elseif(ndeep.eq.4) then
nord=2
npre1=1
npre2=1
nt=40
ntheta=12
ntau=17
elseif(ndeep.eq.5) then
nord=3
npre1=1
npre2=1
nt=40
ntheta=12
ntau=15
elseif(ndeep.eq.6) then
nord=4
npre1=1
npre2=1
nt=95
ntheta=12
ntau=15
endif
do iorder=1,nord
misub(1:k-iorder)=0
misub(k-iorder+1:k)=1
iflag=k-iorder+1
do while(iflag .ge.0)
if(iorder.eq.nord .and. npre1.eq.0) then
iend=iflag
else
iend=1
endif
d1=0.
do n1=iflag,iend,-1
mi=misub
mi(n1)=1
if(any(iand(apmaskr(1:k),mi).eq.1)) cycle
ntotal=ntotal+1
me=ieor(m0,mi)
if(n1.eq.iflag) then
call mrbencode74(me,ce,g2,N,k)
e2sub=ieor(ce(k+1:N),hdec(k+1:N))
e2=e2sub
nd1kpt=sum(e2sub(1:nt))+1
d1=sum(ieor(me(1:k),hdec(1:k))*absrx(1:k))
else
e2=ieor(e2sub,g2(k+1:N,n1))
nd1kpt=sum(e2(1:nt))+2
endif
if(nd1kpt .le. ntheta) then
call mrbencode74(me,ce,g2,N,k)
nxor=ieor(ce,hdec)
if(n1.eq.iflag) then
dd=d1+sum(e2sub*absrx(k+1:N))
else
dd=d1+ieor(ce(n1),hdec(n1))*absrx(n1)+sum(e2*absrx(k+1:N))
endif
if( dd .lt. dmin ) then
dmin=dd
cw=ce
nhardmin=sum(nxor)
nd1kptbest=nd1kpt
endif
else
nrejected=nrejected+1
endif
enddo
! Get the next test error pattern, iflag will go negative
! when the last pattern with weight iorder has been generated.
call nextpat74(misub,k,iorder,iflag)
enddo
enddo
if(npre2.eq.1) then
reset=.true.
ntotal=0
do i1=k,1,-1
do i2=i1-1,1,-1
ntotal=ntotal+1
mi(1:ntau)=ieor(g2(k+1:k+ntau,i1),g2(k+1:k+ntau,i2))
call boxit74(reset,mi(1:ntau),ntau,ntotal,i1,i2)
enddo
enddo
ncount2=0
ntotal2=0
reset=.true.
! Now run through again and do the second pre-processing rule
misub(1:k-nord)=0
misub(k-nord+1:k)=1
iflag=k-nord+1
do while(iflag .ge.0)
me=ieor(m0,misub)
call mrbencode74(me,ce,g2,N,k)
e2sub=ieor(ce(k+1:N),hdec(k+1:N))
do i2=0,ntau
ntotal2=ntotal2+1
ui=0
if(i2.gt.0) ui(i2)=1
r2pat=ieor(e2sub,ui)
778 continue
call fetchit74(reset,r2pat(1:ntau),ntau,in1,in2)
if(in1.gt.0.and.in2.gt.0) then
ncount2=ncount2+1
mi=misub
mi(in1)=1
mi(in2)=1
if(sum(mi).lt.nord+npre1+npre2.or.any(iand(apmaskr(1:k),mi).eq.1)) cycle
me=ieor(m0,mi)
call mrbencode74(me,ce,g2,N,k)
nxor=ieor(ce,hdec)
dd=sum(nxor*absrx)
if( dd .lt. dmin ) then
dmin=dd
cw=ce
nhardmin=sum(nxor)
endif
goto 778
endif
enddo
call nextpat74(misub,k,nord,iflag)
enddo
endif
998 continue
! Re-order the codeword to [message bits][parity bits] format.
cw(indices)=cw
hdec(indices)=hdec
message74=cw(1:74)
call get_crc24(message74,74,nbadcrc)
if(nbadcrc.ne.0) nhardmin=-nhardmin
return
end subroutine osd240_74
subroutine mrbencode74(me,codeword,g2,N,K)
integer*1 me(K),codeword(N),g2(N,K)
! fast encoding for low-weight test patterns
codeword=0
do i=1,K
if( me(i) .eq. 1 ) then
codeword=ieor(codeword,g2(1:N,i))
endif
enddo
return
end subroutine mrbencode74
subroutine nextpat74(mi,k,iorder,iflag)
integer*1 mi(k),ms(k)
! generate the next test error pattern
ind=-1
do i=1,k-1
if( mi(i).eq.0 .and. mi(i+1).eq.1) ind=i
enddo
if( ind .lt. 0 ) then ! no more patterns of this order
iflag=ind
return
endif
ms=0
ms(1:ind-1)=mi(1:ind-1)
ms(ind)=1
ms(ind+1)=0
if( ind+1 .lt. k ) then
nz=iorder-sum(ms)
ms(k-nz+1:k)=1
endif
mi=ms
do i=1,k ! iflag will point to the lowest-index 1 in mi
if(mi(i).eq.1) then
iflag=i
exit
endif
enddo
return
end subroutine nextpat74
subroutine boxit74(reset,e2,ntau,npindex,i1,i2)
integer*1 e2(1:ntau)
integer indexes(5000,2),fp(0:525000),np(5000)
logical reset
common/boxes/indexes,fp,np
if(reset) then
patterns=-1
fp=-1
np=-1
sc=-1
indexes=-1
reset=.false.
endif
indexes(npindex,1)=i1
indexes(npindex,2)=i2
ipat=0
do i=1,ntau
if(e2(i).eq.1) then
ipat=ipat+ishft(1,ntau-i)
endif
enddo
ip=fp(ipat) ! see what's currently stored in fp(ipat)
if(ip.eq.-1) then
fp(ipat)=npindex
else
do while (np(ip).ne.-1)
ip=np(ip)
enddo
np(ip)=npindex
endif
return
end subroutine boxit74
subroutine fetchit74(reset,e2,ntau,i1,i2)
integer indexes(5000,2),fp(0:525000),np(5000)
integer lastpat
integer*1 e2(ntau)
logical reset
common/boxes/indexes,fp,np
save lastpat,inext
if(reset) then
lastpat=-1
reset=.false.
endif
ipat=0
do i=1,ntau
if(e2(i).eq.1) then
ipat=ipat+ishft(1,ntau-i)
endif
enddo
index=fp(ipat)
if(lastpat.ne.ipat .and. index.gt.0) then ! return first set of indices
i1=indexes(index,1)
i2=indexes(index,2)
inext=np(index)
elseif(lastpat.eq.ipat .and. inext.gt.0) then
i1=indexes(inext,1)
i2=indexes(inext,2)
inext=np(inext)
else
i1=-1
i2=-1
inext=-1
endif
lastpat=ipat
return
end subroutine fetchit74

16
lib/fst240_decode.f90
View File

@ -154,7 +154,7 @@ contains
hmod=2**nsubmode
if(nfqso+nqsoprogress.eq.-999) return
Keff=91
iwspr=0
iwspr=1
nmax=15*12000
single_decode=iand(nexp_decode,32).eq.32
if(ntrperiod.eq.15) then
@ -413,6 +413,11 @@ contains
if(ndepth.eq.1) ntmax=nblock
apmask=0
if(iwspr.eq.1) then
nblock=4
ntmax=nblock
endif
do itry=1,ntmax
if(itry.eq.1) llr=llra
if(itry.eq.2.and.itry.le.nblock) llr=llrb
@ -471,8 +476,10 @@ contains
else
maxosd=2
call timer('d240_74 ',0)
! call decode240_74(llr,Keff,maxosd,norder,apmask,message74,cw, &
! ntype,nharderrors,dmin)
Keff=64
norder=4
call decode240_74(llr,Keff,maxosd,norder,apmask,message74,cw, &
ntype,nharderrors,dmin)
call timer('d240_74 ',1)
endif
if(nharderrors .ge.0) then
@ -694,7 +701,8 @@ write(21,'(i6,7i6,f7.1,f9.2,3f7.1,1x,a37)') &
enddo
call pctile(s2(ina+hmod*3:inb-hmod*3),inb-ina+1-hmod*6,30,base)
s2=s2/base !Normalize wrt noise level
thresh=1.25 !First candidate threshold
! thresh=1.25
thresh=1.15 !First candidate threshold
ncand=0
candidates=0