From 6fe9e8f860285b02682f52854c0cca98a9681d4e Mon Sep 17 00:00:00 2001
From: Steve Franke <s.j.franke@icloud.com>
Date: Sat, 9 Jun 2018 13:05:11 -0500
Subject: [PATCH] Remove the need to re-order the parity-check matrix columns
for compatibility with the generator matrix. Redefine the codeword to have
the form [91 message bits|83 parity bits].
---
lib/ft8/bpdecode174_91.f90 | 8 +-
lib/ft8/encode174_91.f90 | 9 +-
lib/ft8/genft8_174_91.f90 | 4 +-
lib/ft8/ldpc_174_91_c_reordered_parity.f90 | 270 +++++++++++++++++++++
lib/ft8/ldpcsim174_91.f90 | 11 +-
lib/ft8/osd174_91.f90 | 16 +-
6 files changed, 287 insertions(+), 31 deletions(-)
create mode 100644 lib/ft8/ldpc_174_91_c_reordered_parity.f90
diff --git a/lib/ft8/bpdecode174_91.f90 b/lib/ft8/bpdecode174_91.f90
index 6280dcaec..31effb5dd 100644
--- a/lib/ft8/bpdecode174_91.f90
+++ b/lib/ft8/bpdecode174_91.f90
@@ -4,7 +4,6 @@ subroutine bpdecode174_91(llr,apmask,maxiterations,decoded,cw,nharderror,iter)
!
integer, parameter:: N=174, K=91, M=N-K
integer*1 codeword(N),cw(N),apmask(N)
-integer colorder(N)
integer*1 decoded(K)
integer Nm(7,M)
integer Mn(3,N) ! 3 checks per bit
@@ -17,8 +16,7 @@ real llr(N)
real Tmn
integer nrw(M),ncw
-include "ldpc_174_91_c_colorder.f90"
-include "ldpc_174_91_c_parity.f90"
+include "ldpc_174_91_c_reordered_parity.f90"
decoded=0
toc=0
@@ -55,8 +53,8 @@ do iter=0,maxiterations
enddo
! write(*,*) 'number of unsatisfied parity checks ',ncheck
if( ncheck .eq. 0 ) then ! we have a codeword - reorder the columns and return it
- codeword=cw(colorder+1)
- decoded=codeword(M+1:N)
+ codeword=cw
+ decoded=codeword(1:K)
nerr=0
do i=1,N
if( (2*cw(i)-1)*llr(i) .lt. 0.0 ) nerr=nerr+1
diff --git a/lib/ft8/encode174_91.f90 b/lib/ft8/encode174_91.f90
index 355a3ad90..6b09f837d 100644
--- a/lib/ft8/encode174_91.f90
+++ b/lib/ft8/encode174_91.f90
@@ -8,12 +8,9 @@ integer, parameter:: N=174, K=91, M=N-K
integer*1 codeword(N)
integer*1 gen(M,K)
-integer*1 itmp(N)
integer*1 message(K)
integer*1 pchecks(M)
-integer colorder(N)
include "ldpc_174_91_c_generator.f90"
-include "ldpc_174_91_c_colorder.f90"
logical first
data first/.true./
save first,gen
@@ -41,9 +38,9 @@ do i=1,M
enddo
pchecks(i)=mod(nsum,2)
enddo
-itmp(1:M)=pchecks
-itmp(M+1:N)=message(1:K)
-codeword(colorder+1)=itmp(1:N)
+
+codeword(1:K)=message
+codeword(K+1:N)=pchecks
return
end subroutine encode174_91
diff --git a/lib/ft8/genft8_174_91.f90 b/lib/ft8/genft8_174_91.f90
index 6561a36b6..0a4c492da 100644
--- a/lib/ft8/genft8_174_91.f90
+++ b/lib/ft8/genft8_174_91.f90
@@ -15,7 +15,6 @@ subroutine genft8_174_91(msg,mygrid,bcontest,i5bit,msgsent,msgbits,itone)
integer itone(79)
integer icos7(0:6)
integer graymap(0:7)
-# data icos7/2,5,6,0,4,1,3/ !Costas 7x7 tone pattern
data icos7/3,1,4,0,6,5,2/ !Costas 7x7 tone pattern
data graymap/0,1,3,2,7,6,4,5/
@@ -49,8 +48,7 @@ subroutine genft8_174_91(msg,mygrid,bcontest,i5bit,msgsent,msgbits,itone)
k=k+1
if(j.eq.30) k=k+7
indx=codeword(i)*4 + codeword(i+1)*2 + codeword(i+2)
-! itone(k)=graymap(indx)
- itone(k)=indx
+ itone(k)=graymap(indx)
enddo
return
diff --git a/lib/ft8/ldpc_174_91_c_reordered_parity.f90 b/lib/ft8/ldpc_174_91_c_reordered_parity.f90
new file mode 100644
index 000000000..2309ad8e8
--- /dev/null
+++ b/lib/ft8/ldpc_174_91_c_reordered_parity.f90
@@ -0,0 +1,270 @@
+data Mn/ &
+ 16, 45, 73, &
+ 25, 51, 62, &
+ 33, 58, 78, &
+ 1, 44, 45, &
+ 2, 7, 61, &
+ 3, 6, 54, &
+ 4, 35, 48, &
+ 5, 13, 21, &
+ 8, 56, 79, &
+ 9, 64, 69, &
+ 10, 19, 66, &
+ 11, 36, 60, &
+ 12, 37, 58, &
+ 14, 32, 43, &
+ 15, 63, 80, &
+ 17, 28, 77, &
+ 18, 74, 83, &
+ 22, 53, 81, &
+ 23, 30, 34, &
+ 24, 31, 40, &
+ 26, 41, 76, &
+ 27, 57, 70, &
+ 29, 49, 65, &
+ 3, 38, 78, &
+ 5, 39, 82, &
+ 46, 50, 73, &
+ 51, 52, 74, &
+ 55, 71, 72, &
+ 44, 67, 72, &
+ 43, 68, 78, &
+ 1, 32, 59, &
+ 2, 6, 71, &
+ 4, 16, 54, &
+ 7, 65, 67, &
+ 8, 30, 42, &
+ 9, 22, 31, &
+ 10, 18, 76, &
+ 11, 23, 82, &
+ 12, 28, 61, &
+ 13, 52, 79, &
+ 14, 50, 51, &
+ 15, 81, 83, &
+ 17, 29, 60, &
+ 19, 33, 64, &
+ 20, 26, 73, &
+ 21, 34, 40, &
+ 24, 27, 77, &
+ 25, 55, 58, &
+ 35, 53, 66, &
+ 36, 48, 68, &
+ 37, 46, 75, &
+ 38, 45, 47, &
+ 39, 57, 69, &
+ 41, 56, 62, &
+ 20, 49, 53, &
+ 46, 52, 63, &
+ 45, 70, 75, &
+ 27, 35, 80, &
+ 1, 15, 30, &
+ 2, 68, 80, &
+ 3, 36, 51, &
+ 4, 28, 51, &
+ 5, 31, 56, &
+ 6, 20, 37, &
+ 7, 40, 82, &
+ 8, 60, 69, &
+ 9, 10, 49, &
+ 11, 44, 57, &
+ 12, 39, 59, &
+ 13, 24, 55, &
+ 14, 21, 65, &
+ 16, 71, 78, &
+ 17, 30, 76, &
+ 18, 25, 80, &
+ 19, 61, 83, &
+ 22, 38, 77, &
+ 23, 41, 50, &
+ 7, 26, 58, &
+ 29, 32, 81, &
+ 33, 40, 73, &
+ 18, 34, 48, &
+ 13, 42, 64, &
+ 5, 26, 43, &
+ 47, 69, 72, &
+ 54, 55, 70, &
+ 45, 62, 68, &
+ 10, 63, 67, &
+ 14, 66, 72, &
+ 22, 60, 74, &
+ 35, 39, 79, &
+ 1, 46, 64, &
+ 1, 24, 66, &
+ 2, 5, 70, &
+ 3, 31, 65, &
+ 4, 49, 58, &
+ 1, 4, 5, &
+ 6, 60, 67, &
+ 7, 32, 75, &
+ 8, 48, 82, &
+ 9, 35, 41, &
+ 10, 39, 62, &
+ 11, 14, 61, &
+ 12, 71, 74, &
+ 13, 23, 78, &
+ 11, 35, 55, &
+ 15, 16, 79, &
+ 7, 9, 16, &
+ 17, 54, 63, &
+ 18, 50, 57, &
+ 19, 30, 47, &
+ 20, 64, 80, &
+ 21, 28, 69, &
+ 22, 25, 43, &
+ 13, 22, 37, &
+ 2, 47, 51, &
+ 23, 54, 74, &
+ 26, 34, 72, &
+ 27, 36, 37, &
+ 21, 36, 63, &
+ 29, 40, 44, &
+ 19, 26, 57, &
+ 3, 46, 82, &
+ 14, 15, 58, &
+ 33, 52, 53, &
+ 30, 43, 52, &
+ 6, 9, 52, &
+ 27, 33, 65, &
+ 25, 69, 73, &
+ 38, 55, 83, &
+ 20, 39, 77, &
+ 18, 29, 56, &
+ 32, 48, 71, &
+ 42, 51, 59, &
+ 28, 44, 79, &
+ 34, 60, 62, &
+ 31, 45, 61, &
+ 46, 68, 77, &
+ 6, 24, 76, &
+ 8, 10, 78, &
+ 40, 41, 70, &
+ 17, 50, 53, &
+ 42, 66, 68, &
+ 4, 22, 72, &
+ 36, 64, 81, &
+ 13, 29, 47, &
+ 2, 8, 81, &
+ 56, 67, 73, &
+ 5, 38, 50, &
+ 12, 38, 64, &
+ 59, 72, 80, &
+ 3, 26, 79, &
+ 45, 76, 81, &
+ 1, 65, 74, &
+ 7, 18, 77, &
+ 11, 56, 59, &
+ 14, 39, 54, &
+ 16, 37, 66, &
+ 10, 28, 55, &
+ 15, 60, 70, &
+ 17, 25, 82, &
+ 20, 30, 31, &
+ 12, 67, 68, &
+ 23, 75, 80, &
+ 27, 32, 62, &
+ 24, 69, 75, &
+ 19, 21, 71, &
+ 34, 53, 61, &
+ 35, 46, 47, &
+ 33, 59, 76, &
+ 40, 43, 83, &
+ 41, 42, 63, &
+ 49, 75, 83, &
+ 20, 44, 48, &
+ 42, 49, 57/
+
+data Nm/ &
+ 4, 31, 59, 91, 92, 96, 153, &
+ 5, 32, 60, 93, 115, 146, 0, &
+ 6, 24, 61, 94, 122, 151, 0, &
+ 7, 33, 62, 95, 96, 143, 0, &
+ 8, 25, 63, 83, 93, 96, 148, &
+ 6, 32, 64, 97, 126, 138, 0, &
+ 5, 34, 65, 78, 98, 107, 154, &
+ 9, 35, 66, 99, 139, 146, 0, &
+ 10, 36, 67, 100, 107, 126, 0, &
+ 11, 37, 67, 87, 101, 139, 158, &
+ 12, 38, 68, 102, 105, 155, 0, &
+ 13, 39, 69, 103, 149, 162, 0, &
+ 8, 40, 70, 82, 104, 114, 145, &
+ 14, 41, 71, 88, 102, 123, 156, &
+ 15, 42, 59, 106, 123, 159, 0, &
+ 1, 33, 72, 106, 107, 157, 0, &
+ 16, 43, 73, 108, 141, 160, 0, &
+ 17, 37, 74, 81, 109, 131, 154, &
+ 11, 44, 75, 110, 121, 166, 0, &
+ 45, 55, 64, 111, 130, 161, 173, &
+ 8, 46, 71, 112, 119, 166, 0, &
+ 18, 36, 76, 89, 113, 114, 143, &
+ 19, 38, 77, 104, 116, 163, 0, &
+ 20, 47, 70, 92, 138, 165, 0, &
+ 2, 48, 74, 113, 128, 160, 0, &
+ 21, 45, 78, 83, 117, 121, 151, &
+ 22, 47, 58, 118, 127, 164, 0, &
+ 16, 39, 62, 112, 134, 158, 0, &
+ 23, 43, 79, 120, 131, 145, 0, &
+ 19, 35, 59, 73, 110, 125, 161, &
+ 20, 36, 63, 94, 136, 161, 0, &
+ 14, 31, 79, 98, 132, 164, 0, &
+ 3, 44, 80, 124, 127, 169, 0, &
+ 19, 46, 81, 117, 135, 167, 0, &
+ 7, 49, 58, 90, 100, 105, 168, &
+ 12, 50, 61, 118, 119, 144, 0, &
+ 13, 51, 64, 114, 118, 157, 0, &
+ 24, 52, 76, 129, 148, 149, 0, &
+ 25, 53, 69, 90, 101, 130, 156, &
+ 20, 46, 65, 80, 120, 140, 170, &
+ 21, 54, 77, 100, 140, 171, 0, &
+ 35, 82, 133, 142, 171, 174, 0, &
+ 14, 30, 83, 113, 125, 170, 0, &
+ 4, 29, 68, 120, 134, 173, 0, &
+ 1, 4, 52, 57, 86, 136, 152, &
+ 26, 51, 56, 91, 122, 137, 168, &
+ 52, 84, 110, 115, 145, 168, 0, &
+ 7, 50, 81, 99, 132, 173, 0, &
+ 23, 55, 67, 95, 172, 174, 0, &
+ 26, 41, 77, 109, 141, 148, 0, &
+ 2, 27, 41, 61, 62, 115, 133, &
+ 27, 40, 56, 124, 125, 126, 0, &
+ 18, 49, 55, 124, 141, 167, 0, &
+ 6, 33, 85, 108, 116, 156, 0, &
+ 28, 48, 70, 85, 105, 129, 158, &
+ 9, 54, 63, 131, 147, 155, 0, &
+ 22, 53, 68, 109, 121, 174, 0, &
+ 3, 13, 48, 78, 95, 123, 0, &
+ 31, 69, 133, 150, 155, 169, 0, &
+ 12, 43, 66, 89, 97, 135, 159, &
+ 5, 39, 75, 102, 136, 167, 0, &
+ 2, 54, 86, 101, 135, 164, 0, &
+ 15, 56, 87, 108, 119, 171, 0, &
+ 10, 44, 82, 91, 111, 144, 149, &
+ 23, 34, 71, 94, 127, 153, 0, &
+ 11, 49, 88, 92, 142, 157, 0, &
+ 29, 34, 87, 97, 147, 162, 0, &
+ 30, 50, 60, 86, 137, 142, 162, &
+ 10, 53, 66, 84, 112, 128, 165, &
+ 22, 57, 85, 93, 140, 159, 0, &
+ 28, 32, 72, 103, 132, 166, 0, &
+ 28, 29, 84, 88, 117, 143, 150, &
+ 1, 26, 45, 80, 128, 147, 0, &
+ 17, 27, 89, 103, 116, 153, 0, &
+ 51, 57, 98, 163, 165, 172, 0, &
+ 21, 37, 73, 138, 152, 169, 0, &
+ 16, 47, 76, 130, 137, 154, 0, &
+ 3, 24, 30, 72, 104, 139, 0, &
+ 9, 40, 90, 106, 134, 151, 0, &
+ 15, 58, 60, 74, 111, 150, 163, &
+ 18, 42, 79, 144, 146, 152, 0, &
+ 25, 38, 65, 99, 122, 160, 0, &
+ 17, 42, 75, 129, 170, 172, 0/
+
+data nrw/ &
+7,6,6,6,7,6,7,6,6,7,6,6,7,7,6,6, &
+6,7,6,7,6,7,6,6,6,7,6,6,6,7,6,6, &
+6,6,7,6,6,6,7,7,6,6,6,6,7,7,6,6, &
+6,6,7,6,6,6,7,6,6,6,6,7,6,6,6,7, &
+6,6,6,7,7,6,6,7,6,6,6,6,6,6,6,7, &
+6,6,6/
+
+ncw=3
diff --git a/lib/ft8/ldpcsim174_91.f90 b/lib/ft8/ldpcsim174_91.f90
index bdb16ac42..5b58dd177 100644
--- a/lib/ft8/ldpcsim174_91.f90
+++ b/lib/ft8/ldpcsim174_91.f90
@@ -13,14 +13,11 @@ integer*1 msgbits(K)
integer*1 apmask(N), cw(N)
integer*2 checksum
integer*4 i4Msg6BitWords(13)
-integer colorder(N)
integer nerrtot(N),nerrdec(N),nmpcbad(K)
logical checksumok
real*8, allocatable :: rxdata(:)
real, allocatable :: llr(:)
-include "ldpc_174_91_c_colorder.f90"
-
nerrtot=0
nerrdec=0
nmpcbad=0 ! Used to collect the number of errors in the message+crc part of the codeword
@@ -51,8 +48,8 @@ write(*,*) "niter= ",max_iterations," s= ",s
allocate ( codeword(N), decoded(K), message(K) )
allocate ( rxdata(N), llr(N) )
- msg="K1JT K9AN EN50"
-! msg="G4WJS K9AN EN50"
+! msg="K1JT K9AN EN50"
+ msg="G4WJS K9AN EN50"
call packmsg(msg,i4Msg6BitWords,itype,.false.) !Pack into 12 6-bit bytes
call unpackmsg(i4Msg6BitWords,msgsent,.false.,grid) !Unpack to get msgsent
write(*,*) "message sent ",msgsent
@@ -148,9 +145,9 @@ do idb = 20,-10,-1
llr=2.0*rxdata/(ss*ss)
nap=0 ! number of AP bits
- llr(colorder(174-91+1:174-91+nap)+1)=5*(2.0*msgbits(1:nap)-1.0)
+ llr(1:nap)=5*(2.0*msgbits(1:nap)-1.0)
apmask=0
- apmask(colorder(174-91+1:174-91+nap)+1)=1
+ apmask(1:nap)=1
! max_iterations is max number of belief propagation iterations
call bpdecode174_91(llr, apmask, max_iterations, decoded, cw, nharderrors,niterations)
diff --git a/lib/ft8/osd174_91.f90 b/lib/ft8/osd174_91.f90
index 34419f98f..7a9cb1076 100644
--- a/lib/ft8/osd174_91.f90
+++ b/lib/ft8/osd174_91.f90
@@ -8,7 +8,6 @@ integer*1 gen(K,N)
integer*1 genmrb(K,N),g2(N,K)
integer*1 temp(K),m0(K),me(K),mi(K),misub(K),e2sub(N-K),e2(N-K),ui(N-K)
integer*1 r2pat(N-K)
-integer colorder(N)
integer indices(N),nxor(N)
integer*1 cw(N),ce(N),c0(N),hdec(N)
integer*1 decoded(K)
@@ -16,7 +15,6 @@ integer indx(N)
real llr(N),rx(N),absrx(N)
include "ldpc_174_91_c_generator.f90"
-include "ldpc_174_91_c_colorder.f90"
logical first,reset
data first/.true./
@@ -31,19 +29,18 @@ if( first ) then ! fill the generator matrix
if(j.eq.23) ibmax=3
do jj=1, ibmax
irow=(j-1)*4+jj
- if( btest(istr,4-jj) ) gen(irow,i)=1
+ if( btest(istr,4-jj) ) gen(irow,K+i)=1
enddo
enddo
enddo
do irow=1,K
- gen(irow,M+irow)=1
+ gen(irow,irow)=1
enddo
first=.false.
endif
-! Re-order received vector to place systematic msg bits at the end.
-rx=llr(colorder+1)
-apmaskr=apmask(colorder+1)
+rx=llr
+apmaskr=apmask
! Hard decisions on the received word.
hdec=0
@@ -246,11 +243,10 @@ if(npre2.eq.1) then
endif
998 continue
-! Re-order the codeword to place message bits at the end.
+! Re-order the codeword to [message bits][parity bits] format.
cw(indices)=cw
hdec(indices)=hdec
-decoded=cw(M+1:N)
-cw(colorder+1)=cw ! put the codeword back into received-word order
+decoded=cw(1:K)
return
end subroutine osd174_91