mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-09-27 15:46:51 -04:00
For (174,91) code, move CRC generation and testing into encode and decode routines. Make ldpcsim174_91.f90 work with the new encode/decode routines.
This commit is contained in:
Steve Franke
parent
2cdb164446
commit
1a31e5b2d6
@ -1,7 +1,6 @@
|
||||
subroutine encode128_90(message77,codeword)
|
||||
! Encode an 90-bit message and return a 128-bit codeword.
|
||||
! The generator matrix has dimensions (38,90).
|
||||
! The code is a (128,90) regular ldpc code with column weight 3.
|
||||
!
|
||||
! Add a 13-bit CRC to a 77-bit message and return a 128-bit codeword
|
||||
!
|
||||
use, intrinsic :: iso_c_binding
|
||||
use iso_c_binding, only: c_loc,c_size_t
|
||||
|
||||
@ -1,10 +1,14 @@
|
||||
subroutine bpdecode174_91(llr,apmask,maxiterations,decoded,cw,nharderror,iter)
|
||||
subroutine bpdecode174_91(llr,apmask,maxiterations,message77,cw,nharderror,iter)
|
||||
!
|
||||
! A log-domain belief propagation decoder for the (174,91) code.
|
||||
!
|
||||
use iso_c_binding, only: c_loc,c_size_t
|
||||
use crc
|
||||
integer, parameter:: N=174, K=91, M=N-K
|
||||
integer*1 codeword(N),cw(N),apmask(N)
|
||||
integer*1 cw(N),apmask(N)
|
||||
integer*1 decoded(K)
|
||||
integer*1 message77(77)
|
||||
integer nrw(M),ncw
|
||||
integer Nm(7,M)
|
||||
integer Mn(3,N) ! 3 checks per bit
|
||||
integer synd(M)
|
||||
@ -14,7 +18,6 @@ real tanhtoc(7,M)
|
||||
real zn(N)
|
||||
real llr(N)
|
||||
real Tmn
|
||||
integer nrw(M),ncw
|
||||
|
||||
include "ldpc_174_91_c_reordered_parity.f90"
|
||||
|
||||
@ -52,15 +55,14 @@ do iter=0,maxiterations
|
||||
! if( mod(synd(i),2) .ne. 0 ) write(*,*) 'check ',i,' unsatisfied'
|
||||
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
|
||||
decoded=codeword(1:K)
|
||||
nerr=0
|
||||
do i=1,N
|
||||
if( (2*cw(i)-1)*llr(i) .lt. 0.0 ) nerr=nerr+1
|
||||
enddo
|
||||
nharderror=nerr
|
||||
return
|
||||
if( ncheck .eq. 0 ) then ! we have a codeword - if crc is good, return it
|
||||
decoded=cw(1:K)
|
||||
call chkcrc14a(decoded,nbadcrc)
|
||||
nharderror=count( (2*cw-1)*llr .lt. 0.0 )
|
||||
if(nbadcrc.eq.0) then
|
||||
message77=decoded(1:77)
|
||||
return
|
||||
endif
|
||||
endif
|
||||
|
||||
if( iter.gt.0 ) then ! this code block implements an early stopping criterion
|
||||
|
||||
@ -1,15 +1,18 @@
|
||||
subroutine encode174_91(message,codeword)
|
||||
! Encode an 91-bit message and return a 174-bit codeword.
|
||||
! The generator matrix has dimensions (83,91).
|
||||
! The code is a (174,91) regular ldpc code with column weight 3.
|
||||
subroutine encode174_91(message77,codeword)
|
||||
!
|
||||
! Add a 14-bit CRC to a 77-bit message and return a 174-bit codeword
|
||||
!
|
||||
use, intrinsic :: iso_c_binding
|
||||
use iso_c_binding, only: c_loc,c_size_t
|
||||
use crc
|
||||
|
||||
integer, parameter:: N=174, K=91, M=N-K
|
||||
|
||||
character*91 tmpchar
|
||||
integer*1 codeword(N)
|
||||
integer*1 gen(M,K)
|
||||
integer*1 message(K)
|
||||
integer*1 message77(77),message(K)
|
||||
integer*1 pchecks(M)
|
||||
integer*1, target :: i1MsgBytes(12)
|
||||
include "ldpc_174_91_c_generator.f90"
|
||||
logical first
|
||||
data first/.true./
|
||||
@ -31,6 +34,15 @@ if( first ) then ! fill the generator matrix
|
||||
first=.false.
|
||||
endif
|
||||
|
||||
! Add 14-bit CRC to form 91-bit message+CRC14
|
||||
write(tmpchar,'(77i1)') message77
|
||||
tmpchar(78:80)='000'
|
||||
i1MsgBytes=0
|
||||
read(tmpchar,'(10b8)') i1MsgBytes(1:10)
|
||||
ncrc14 = crc14 (c_loc (i1MsgBytes), 12)
|
||||
write(tmpchar(78:91),'(b14)') ncrc14
|
||||
read(tmpchar,'(91i1)') message
|
||||
|
||||
do i=1,M
|
||||
nsum=0
|
||||
do j=1,K
|
||||
|
||||
@ -7,20 +7,18 @@ integer, parameter:: N=174, K=91, M=N-K
|
||||
character*22 msg,msgsent,msgreceived
|
||||
character*8 arg
|
||||
character*6 grid
|
||||
character*96 tmpchar
|
||||
integer*1, allocatable :: codeword(:), decoded(:), message(:)
|
||||
integer*1, target:: i1Msg8BitBytes(12)
|
||||
integer*1 msgbits(K)
|
||||
integer*1 msgbits(77)
|
||||
integer*1 message77(77)
|
||||
integer*1 apmask(N), cw(N)
|
||||
integer*2 checksum
|
||||
integer*4 i4Msg6BitWords(13)
|
||||
integer nerrtot(N),nerrdec(N),nmpcbad(K)
|
||||
logical checksumok
|
||||
integer nerrtot(0:N),nerrdec(0:N)
|
||||
real*8, allocatable :: rxdata(:)
|
||||
real, allocatable :: llr(:)
|
||||
|
||||
nerrtot=0
|
||||
nerrdec=0
|
||||
nmpcbad=0 ! Used to collect the number of errors in the message+crc part of the codeword
|
||||
|
||||
nargs=iargc()
|
||||
if(nargs.ne.4) then
|
||||
@ -54,73 +52,31 @@ allocate ( rxdata(N), llr(N) )
|
||||
call unpackmsg(i4Msg6BitWords,msgsent,.false.,grid) !Unpack to get msgsent
|
||||
write(*,*) "message sent ",msgsent
|
||||
|
||||
i4=0
|
||||
ik=0
|
||||
im=0
|
||||
do i=1,12
|
||||
nn=i4Msg6BitWords(i)
|
||||
do j=1, 6
|
||||
ik=ik+1
|
||||
i4=i4+i4+iand(1,ishft(nn,j-6))
|
||||
i4=iand(i4,255)
|
||||
if(ik.eq.8) then
|
||||
im=im+1
|
||||
! if(i4.gt.127) i4=i4-256
|
||||
i1Msg8BitBytes(im)=i4
|
||||
ik=0
|
||||
endif
|
||||
enddo
|
||||
enddo
|
||||
|
||||
i1Msg8BitBytes(10:12)=0
|
||||
checksum = crc14 (c_loc (i1Msg8BitBytes), 12)
|
||||
! For reference, the next 3 lines show how to check the CRC
|
||||
i1Msg8BitBytes(11)=checksum/256
|
||||
i1Msg8BitBytes(12)=iand (checksum,255)
|
||||
checksumok = crc14_check(c_loc (i1Msg8BitBytes), 12)
|
||||
if( checksumok ) write(*,*) 'Good checksum'
|
||||
|
||||
! K=91, For now:
|
||||
! msgbits(1:72) JT message bits
|
||||
! msgbits(73:77) 5 free message bits (set to 0)
|
||||
! msgbits(78:91) CRC14
|
||||
mbit=0
|
||||
do i=1, 9
|
||||
i1=i1Msg8BitBytes(i)
|
||||
do ibit=1,8
|
||||
mbit=mbit+1
|
||||
msgbits(mbit)=iand(1,ishft(i1,ibit-8))
|
||||
enddo
|
||||
enddo
|
||||
msgbits(73:77)=0 ! the five extra message bits go here
|
||||
i1=i1Msg8BitBytes(11) ! First 6 bits of crc12 are LSB of this byte
|
||||
do ibit=1,6
|
||||
msgbits(77+ibit)=iand(1,ishft(i1,ibit-6))
|
||||
enddo
|
||||
i1=i1Msg8BitBytes(12) ! Now shift in last 8 bits of the CRC
|
||||
do ibit=1,8
|
||||
msgbits(83+ibit)=iand(1,ishft(i1,ibit-8))
|
||||
enddo
|
||||
tmpchar=' '
|
||||
write(tmpchar,'(12b6.6)') i4Msg6BitWords(1:12)
|
||||
tmpchar(73:77)='00000' !i5bit
|
||||
read(tmpchar,'(77i1)') msgbits(1:77)
|
||||
|
||||
write(*,*) 'message'
|
||||
write(*,'(12(8i1,1x))') msgbits
|
||||
write(*,'(28i1,1x,28i1,1x,16i1,1x,5i1)') msgbits
|
||||
|
||||
! msgbits is the 77-bit message, codeword is 174 bits
|
||||
call encode174_91(msgbits,codeword)
|
||||
|
||||
call init_random_seed()
|
||||
! call sgran()
|
||||
|
||||
write(*,*) 'codeword'
|
||||
write(*,'(22(8i1,1x))') codeword
|
||||
|
||||
write(*,*) "Eb/N0 SNR2500 ngood nundetected nbadcrc sigma"
|
||||
write(*,*) "Eb/N0 SNR2500 ngood nundetected sigma psymerr"
|
||||
do idb = 20,-10,-1
|
||||
!do idb = 0,0,-1
|
||||
db=idb/2.0-1.0
|
||||
sigma=1/sqrt( 2*rate*(10**(db/10.0)) )
|
||||
ngood=0
|
||||
nue=0
|
||||
nbadcrc=0
|
||||
nberr=0
|
||||
nsumerr=0
|
||||
|
||||
do itrial=1, ntrials
|
||||
! Create a realization of a noisy received word
|
||||
do i=1,N
|
||||
@ -131,7 +87,6 @@ do idb = 20,-10,-1
|
||||
if( rxdata(i)*(2*codeword(i)-1.0) .lt. 0 ) nerr=nerr+1
|
||||
enddo
|
||||
if(nerr.ge.1) nerrtot(nerr)=nerrtot(nerr)+1
|
||||
nberr=nberr+nerr
|
||||
|
||||
rxav=sum(rxdata)/N
|
||||
rx2av=sum(rxdata*rxdata)/N
|
||||
@ -150,38 +105,26 @@ do idb = 20,-10,-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)
|
||||
if( ndepth .ge. 0 .and. nharderrors .lt. 0 ) call osd174_91(llr, apmask, ndepth, decoded, cw, nharderrors, dmin)
|
||||
call bpdecode174_91(llr, apmask, max_iterations, message77, cw, nharderrors,niterations)
|
||||
if( ndepth .ge. 0 .and. nharderrors .lt. 0 ) call osd174_91(llr, apmask, ndepth, message77, cw, nharderrors, dmin)
|
||||
! If the decoder finds a valid codeword, nharderrors will be .ge. 0.
|
||||
if( nharderrors .ge. 0 ) then
|
||||
call extractmessage174_91(decoded,msgreceived,ncrcflag)
|
||||
if( ncrcflag .ne. 1 ) then
|
||||
nbadcrc=nbadcrc+1
|
||||
endif
|
||||
|
||||
nueflag=0
|
||||
nerrmpc=0
|
||||
do i=1,K ! find number of errors in message+crc part of codeword
|
||||
if( msgbits(i) .ne. decoded(i) ) then
|
||||
nueflag=1
|
||||
nerrmpc=nerrmpc+1
|
||||
endif
|
||||
enddo
|
||||
if(nerrmpc.ge.1) nmpcbad(nerrmpc)=nmpcbad(nerrmpc)+1
|
||||
if( ncrcflag .eq. 1 ) then
|
||||
if( nueflag .eq. 0 ) then
|
||||
ngood=ngood+1
|
||||
if(nerr.ge.1) nerrdec(nerr)=nerrdec(nerr)+1
|
||||
else if( nueflag .eq. 1 ) then
|
||||
nue=nue+1;
|
||||
endif
|
||||
call extractmessage77(message77,msgreceived)
|
||||
nhw=count(cw.ne.codeword)
|
||||
if(nhw.eq.0) then ! this is a good decode
|
||||
ngood=ngood+1
|
||||
nerrdec(nerr)=nerrdec(nerr)+1
|
||||
else
|
||||
nue=nue+1
|
||||
endif
|
||||
endif
|
||||
nsumerr=nsumerr+nerr
|
||||
enddo
|
||||
|
||||
baud=12000/1920
|
||||
snr2500=db+10.0*log10((baud/2500.0))
|
||||
pberr=real(nberr)/(real(ntrials*N))
|
||||
write(*,"(f4.1,4x,f5.1,1x,i8,1x,i8,1x,i8,8x,f5.2,8x,e10.3)") db,SNR2500,ngood,nue,nbadcrc,ss,pberr
|
||||
pberr=real(nsumerr)/(real(ntrials*N))
|
||||
write(*,"(f4.1,4x,f5.1,1x,i8,1x,i8,8x,f5.2,8x,e10.3)") db,SNR2500,ngood,nue,ss,pberr
|
||||
|
||||
enddo
|
||||
|
||||
@ -190,10 +133,5 @@ do i=1,174
|
||||
write(23,'(i4,2x,i10,i10,f10.2)') i,nerrdec(i),nerrtot(i),real(nerrdec(i))/real(nerrtot(i)+1e-10)
|
||||
enddo
|
||||
close(23)
|
||||
open(unit=25,file='nmpcbad.dat',status='unknown')
|
||||
do i=1,87
|
||||
write(25,'(i4,2x,i10)') i,nmpcbad(i)
|
||||
enddo
|
||||
close(25)
|
||||
|
||||
end program ldpcsim174_91
|
||||
|
||||
@ -1,4 +1,4 @@
|
||||
subroutine osd174_91(llr,apmask,ndeep,decoded,cw,nhardmin,dmin)
|
||||
subroutine osd174_91(llr,apmask,ndeep,message77,cw,nhardmin,dmin)
|
||||
!
|
||||
! An ordered-statistics decoder for the (174,91) code.
|
||||
!
|
||||
@ -11,6 +11,7 @@ integer*1 r2pat(N-K)
|
||||
integer indices(N),nxor(N)
|
||||
integer*1 cw(N),ce(N),c0(N),hdec(N)
|
||||
integer*1 decoded(K)
|
||||
integer*1 message77(77)
|
||||
integer indx(N)
|
||||
real llr(N),rx(N),absrx(N)
|
||||
|
||||
@ -247,6 +248,10 @@ endif
|
||||
cw(indices)=cw
|
||||
hdec(indices)=hdec
|
||||
decoded=cw(1:K)
|
||||
call chkcrc14a(decoded,nbadcrc)
|
||||
message77=decoded(1:77)
|
||||
if(nbadcrc.eq.1) nhardmin=-nhardmin
|
||||
|
||||
return
|
||||
end subroutine osd174_91
|
||||
|
||||
|
||||
@ -9,9 +9,8 @@ character*8 arg
|
||||
integer*1 codeword(N), message77(77)
|
||||
integer*1 apmask(N),cw(N)
|
||||
integer*1 msgbits(77)
|
||||
integer*2 ncrc13
|
||||
integer*4 i4Msg6BitWords(13)
|
||||
integer nerrtot(0:N),nerrdec(0:N),nmpcbad(0:K),nbadwt(0:N)
|
||||
integer nerrtot(0:N),nerrdec(0:N)
|
||||
real*8 rxdata(N), rxavgd(N)
|
||||
real llr(N)
|
||||
|
||||
@ -20,8 +19,6 @@ do i=1,NRECENT
|
||||
enddo
|
||||
nerrtot=0
|
||||
nerrdec=0
|
||||
nmpcbad=0
|
||||
nbadwt=0
|
||||
|
||||
nargs=iargc()
|
||||
if(nargs.ne.4) then
|
||||
@ -55,7 +52,7 @@ msg="G4WJS K1JT FN20"
|
||||
read(tmpchar,'(77i1)') msgbits(1:77)
|
||||
|
||||
write(*,*) 'msgbits'
|
||||
write(*,'(28i1,1x,28i1,1x,16i1,1x,5i1,1x,13i1)') msgbits
|
||||
write(*,'(28i1,1x,28i1,1x,16i1,1x,5i1)') msgbits
|
||||
|
||||
! msgbits is the 77-bit message, codeword is 128 bits
|
||||
call encode128_90(msgbits,codeword)
|
||||
@ -109,7 +106,7 @@ do idb = 14,-6,-1
|
||||
! If the decoder finds a valid codeword, nharderrors will be .ge. 0.
|
||||
if( nharderrors .ge. 0 ) then
|
||||
call extractmessage77(message77,msgreceived)
|
||||
nhw=count(message77.ne.codeword(1:77))
|
||||
nhw=count(cw.ne.codeword)
|
||||
if(nhw.eq.0) then ! this is a good decode
|
||||
ngood=ngood+1
|
||||
nerrdec(nerr)=nerrdec(nerr)+1
|
||||
@ -132,10 +129,4 @@ do i=0,N
|
||||
enddo
|
||||
close(23)
|
||||
|
||||
open(unit=25,file='badcrc_hamming_weight.dat',status='unknown')
|
||||
do i=0,N
|
||||
write(25,'(i4,2x,i10)') i,nbadwt(i)
|
||||
enddo
|
||||
close(25)
|
||||
|
||||
end program ldpcsim
|
||||
|
||||
Loading…
Reference in New Issue
Block a user