mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2025-02-03 09:44:24 -05:00
Working toward whole-hog switchover to new LDPC code with 77 bit messages in MSK144.
This commit is contained in:
Steve Franke
parent
42f75bf404
commit
622ed4a3ab
@ -8,18 +8,18 @@ subroutine bpdecode128_90(llr,apmask,maxiterations,message77,cw,nharderror,iter)
|
|||||||
integer*1 cw(N),apmask(N)
|
integer*1 cw(N),apmask(N)
|
||||||
integer*1 decoded(K)
|
integer*1 decoded(K)
|
||||||
integer*1 message77(77)
|
integer*1 message77(77)
|
||||||
integer Nm(12,M)
|
integer Nm(11,M)
|
||||||
integer Mn(4,N)
|
integer Mn(3,N)
|
||||||
integer nrw(M),ncw(N)
|
integer nrw(M)
|
||||||
integer synd(M)
|
integer synd(M)
|
||||||
real tov(4,N)
|
real tov(4,N)
|
||||||
real toc(12,M)
|
real toc(11,M)
|
||||||
real tanhtoc(12,M)
|
real tanhtoc(11,M)
|
||||||
real zn(N)
|
real zn(N)
|
||||||
real llr(N)
|
real llr(N)
|
||||||
real Tmn
|
real Tmn
|
||||||
|
|
||||||
include "ldpc_128_90_b_reordered_parity.f90"
|
include "ldpc_128_90_reordered_parity.f90"
|
||||||
|
|
||||||
decoded=0
|
decoded=0
|
||||||
toc=0
|
toc=0
|
||||||
@ -39,7 +39,7 @@ subroutine bpdecode128_90(llr,apmask,maxiterations,message77,cw,nharderror,iter)
|
|||||||
! Update bit log likelihood ratios (tov=0 in iteration 0).
|
! Update bit log likelihood ratios (tov=0 in iteration 0).
|
||||||
do i=1,N
|
do i=1,N
|
||||||
if( apmask(i) .ne. 1 ) then
|
if( apmask(i) .ne. 1 ) then
|
||||||
zn(i)=llr(i)+sum(tov(1:ncw(i),i))
|
zn(i)=llr(i)+sum(tov(1:ncw,i))
|
||||||
else
|
else
|
||||||
zn(i)=llr(i)
|
zn(i)=llr(i)
|
||||||
endif
|
endif
|
||||||
@ -74,7 +74,7 @@ subroutine bpdecode128_90(llr,apmask,maxiterations,message77,cw,nharderror,iter)
|
|||||||
ncnt=ncnt+1
|
ncnt=ncnt+1
|
||||||
endif
|
endif
|
||||||
! write(*,*) iter,ncheck,nd,ncnt
|
! write(*,*) iter,ncheck,nd,ncnt
|
||||||
if( ncnt .ge. 5 .and. iter .ge. 10 .and. ncheck .gt. 15) then
|
if( ncnt .ge. 3 .and. iter .ge. 5 .and. ncheck .gt. 10) then
|
||||||
nharderror=-1
|
nharderror=-1
|
||||||
return
|
return
|
||||||
endif
|
endif
|
||||||
@ -86,7 +86,7 @@ subroutine bpdecode128_90(llr,apmask,maxiterations,message77,cw,nharderror,iter)
|
|||||||
do i=1,nrw(j)
|
do i=1,nrw(j)
|
||||||
ibj=Nm(i,j)
|
ibj=Nm(i,j)
|
||||||
toc(i,j)=zn(ibj)
|
toc(i,j)=zn(ibj)
|
||||||
do kk=1,4 ! subtract off what the bit had received from the check
|
do kk=1,ncw ! subtract off what the bit had received from the check
|
||||||
if( Mn(kk,ibj) .eq. j ) then
|
if( Mn(kk,ibj) .eq. j ) then
|
||||||
toc(i,j)=toc(i,j)-tov(kk,ibj)
|
toc(i,j)=toc(i,j)-tov(kk,ibj)
|
||||||
endif
|
endif
|
||||||
@ -96,11 +96,11 @@ subroutine bpdecode128_90(llr,apmask,maxiterations,message77,cw,nharderror,iter)
|
|||||||
|
|
||||||
! send messages from check nodes to variable nodes
|
! send messages from check nodes to variable nodes
|
||||||
do i=1,M
|
do i=1,M
|
||||||
tanhtoc(1:12,i)=tanh(-toc(1:12,i)/2)
|
tanhtoc(1:11,i)=tanh(-toc(1:11,i)/2)
|
||||||
enddo
|
enddo
|
||||||
|
|
||||||
do j=1,N
|
do j=1,N
|
||||||
do i=1,ncw(j)
|
do i=1,ncw
|
||||||
ichk=Mn(i,j) ! Mn(:,j) are the checks that include bit j
|
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)
|
Tmn=product(tanhtoc(1:nrw(ichk),ichk),mask=Nm(1:nrw(ichk),ichk).ne.j)
|
||||||
call platanh(-Tmn,y)
|
call platanh(-Tmn,y)
|
||||||
|
|||||||
116
lib/bpdecode128_90.f90.save
Normal file
116
lib/bpdecode128_90.f90.save
Normal file
@ -0,0 +1,116 @@
|
|||||||
|
subroutine bpdecode128_90(llr,apmask,maxiterations,message77,cw,nharderror,iter)
|
||||||
|
!
|
||||||
|
! A log-domain belief propagation decoder for the (128,90) code.
|
||||||
|
!
|
||||||
|
use iso_c_binding, only: c_loc,c_size_t
|
||||||
|
use crc
|
||||||
|
integer, parameter:: N=128, K=90, M=N-K
|
||||||
|
integer*1 cw(N),apmask(N)
|
||||||
|
integer*1 decoded(K)
|
||||||
|
integer*1 message77(77)
|
||||||
|
integer Nm(12,M)
|
||||||
|
integer Mn(4,N)
|
||||||
|
integer nrw(M),ncw(N)
|
||||||
|
integer synd(M)
|
||||||
|
real tov(4,N)
|
||||||
|
real toc(12,M)
|
||||||
|
real tanhtoc(12,M)
|
||||||
|
real zn(N)
|
||||||
|
real llr(N)
|
||||||
|
real Tmn
|
||||||
|
|
||||||
|
include "ldpc_128_90_b_reordered_parity.f90"
|
||||||
|
|
||||||
|
decoded=0
|
||||||
|
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
|
||||||
|
|
||||||
|
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),i))
|
||||||
|
else
|
||||||
|
zn(i)=llr(i)
|
||||||
|
endif
|
||||||
|
enddo
|
||||||
|
|
||||||
|
! 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
|
||||||
|
! 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
|
||||||
|
decoded=cw(1:K)
|
||||||
|
call chkcrc13a(decoded,nbadcrc)
|
||||||
|
if(nbadcrc.eq.0) then
|
||||||
|
message77=decoded(1:77)
|
||||||
|
nharderror=count( (2*cw-1)*llr .lt. 0.0 )
|
||||||
|
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. 3 .and. iter .ge. 5 .and. ncheck .gt. 10) then
|
||||||
|
nharderror=-1
|
||||||
|
return
|
||||||
|
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=1,4 ! 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(1:12,i)=tanh(-toc(1:12,i)/2)
|
||||||
|
enddo
|
||||||
|
|
||||||
|
do j=1,N
|
||||||
|
do i=1,ncw(j)
|
||||||
|
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
|
||||||
|
nharderror=-1
|
||||||
|
return
|
||||||
|
|
||||||
|
end subroutine bpdecode128_90
|
||||||
58
lib/encode_128_90.f90
Normal file
58
lib/encode_128_90.f90
Normal file
@ -0,0 +1,58 @@
|
|||||||
|
subroutine encode_128_90(message77,codeword)
|
||||||
|
!
|
||||||
|
! 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
|
||||||
|
use crc
|
||||||
|
|
||||||
|
integer, parameter:: N=128, K=90, M=N-K
|
||||||
|
character*90 tmpchar
|
||||||
|
integer*1 codeword(N)
|
||||||
|
integer*1 gen(M,K)
|
||||||
|
integer*1 message77(77),message(K)
|
||||||
|
integer*1 pchecks(M)
|
||||||
|
integer*1, target :: i1MsgBytes(12)
|
||||||
|
include "ldpc_128_90_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=1,23
|
||||||
|
read(g(i)(j:j),"(Z1)") istr
|
||||||
|
ibmax=4
|
||||||
|
if(j.eq.23) 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
|
||||||
|
|
||||||
|
! Add 13 bit CRC to form 90-bit message+CRC13
|
||||||
|
write(tmpchar,'(77i1)') message77
|
||||||
|
tmpchar(78:80)='000'
|
||||||
|
i1MsgBytes=0
|
||||||
|
read(tmpchar,'(10b8)') i1MsgBytes(1:10)
|
||||||
|
ncrc13 = crc13 (c_loc (i1MsgBytes), 12)
|
||||||
|
write(tmpchar(78:90),'(b13)') ncrc13
|
||||||
|
read(tmpchar,'(90i1)') message
|
||||||
|
|
||||||
|
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 encode_128_90
|
||||||
114
lib/genmsk_128_90.f90
Normal file
114
lib/genmsk_128_90.f90
Normal file
@ -0,0 +1,114 @@
|
|||||||
|
subroutine genmsk_128_90(msg0,mygrid,ichk,bcontest,msgsent,i4tone,itype)
|
||||||
|
! s8 + 48bits + s8 + 80 bits = 144 bits (72ms message duration)
|
||||||
|
!
|
||||||
|
! Encode an MSK144 message
|
||||||
|
! Input:
|
||||||
|
! - msg0 requested message to be transmitted
|
||||||
|
! - ichk if ichk=1, return only msgsent
|
||||||
|
! if ichk.ge.10000, set imsg=ichk-10000 for short msg
|
||||||
|
! - msgsent message as it will be decoded
|
||||||
|
! - i4tone array of audio tone values, 0 or 1
|
||||||
|
! - itype message type
|
||||||
|
! 1 = standard message "Call_1 Call_2 Grid/Rpt"
|
||||||
|
! 2 = type 1 prefix
|
||||||
|
! 3 = type 1 suffix
|
||||||
|
! 4 = type 2 prefix
|
||||||
|
! 5 = type 2 suffix
|
||||||
|
! 6 = free text (up to 13 characters)
|
||||||
|
! 7 = short message "<Call_1 Call2> Rpt"
|
||||||
|
|
||||||
|
use iso_c_binding, only: c_loc,c_size_t
|
||||||
|
use packjt77
|
||||||
|
character*37 msg0
|
||||||
|
character*37 message !Message to be generated
|
||||||
|
character*37 msgsent !Message as it will be received
|
||||||
|
character*77 c77
|
||||||
|
character*6 mygrid
|
||||||
|
integer*4 i4tone(144)
|
||||||
|
integer*1 codeword(128)
|
||||||
|
integer*1 msgbits(77)
|
||||||
|
integer*1 bitseq(144) !Tone #s, data and sync (values 0-1)
|
||||||
|
integer*1 s8(8)
|
||||||
|
logical bcontest
|
||||||
|
real*8 pp(12)
|
||||||
|
real*8 xi(864),xq(864),pi,twopi
|
||||||
|
data s8/0,1,1,1,0,0,1,0/
|
||||||
|
equivalence (ihash,i1hash)
|
||||||
|
logical first
|
||||||
|
data first/.true./
|
||||||
|
save
|
||||||
|
|
||||||
|
if(first) then
|
||||||
|
first=.false.
|
||||||
|
nsym=128
|
||||||
|
pi=4.0*atan(1.0)
|
||||||
|
twopi=8.*atan(1.0)
|
||||||
|
do i=1,12
|
||||||
|
pp(i)=sin((i-1)*pi/12)
|
||||||
|
enddo
|
||||||
|
endif
|
||||||
|
|
||||||
|
if(msg0(1:1).eq.'@') then !Generate a fixed tone
|
||||||
|
read(msg0(2:5),*,end=1,err=1) nfreq !at specified frequency
|
||||||
|
go to 2
|
||||||
|
1 nfreq=1000
|
||||||
|
2 i4tone(1)=nfreq
|
||||||
|
else
|
||||||
|
message=msg0
|
||||||
|
do i=1,22
|
||||||
|
if(ichar(message(i:i)).eq.0) then
|
||||||
|
message(i:)=' '
|
||||||
|
exit
|
||||||
|
endif
|
||||||
|
enddo
|
||||||
|
|
||||||
|
do i=1,22 !Strip leading blanks
|
||||||
|
if(message(1:1).ne.' ') exit
|
||||||
|
message=message(i+1:)
|
||||||
|
enddo
|
||||||
|
|
||||||
|
if(message(1:1).eq.'<') then
|
||||||
|
call genmsk40(message,msgsent,ichk,i4tone,itype)
|
||||||
|
if(itype.lt.0) go to 999
|
||||||
|
i4tone(41)=-40
|
||||||
|
go to 999
|
||||||
|
endif
|
||||||
|
|
||||||
|
call pack77(message,i3,n3,c77)
|
||||||
|
call unpack77(c77,msgsent) !Unpack to get msgsent
|
||||||
|
if(ichk.eq.1) go to 999
|
||||||
|
read(c77,"77i1") msgbits
|
||||||
|
call encode_128_90(msgbits,codeword)
|
||||||
|
|
||||||
|
!Create 144-bit channel vector:
|
||||||
|
!8-bit sync word + 48 bits + 8-bit sync word + 80 bits
|
||||||
|
bitseq=0
|
||||||
|
bitseq(1:8)=s8
|
||||||
|
bitseq(9:56)=codeword(1:48)
|
||||||
|
bitseq(57:64)=s8
|
||||||
|
bitseq(65:144)=codeword(49:128)
|
||||||
|
bitseq=2*bitseq-1
|
||||||
|
|
||||||
|
xq(1:6)=bitseq(1)*pp(7:12) !first bit is mapped to 1st half-symbol on q
|
||||||
|
do i=1,71
|
||||||
|
is=(i-1)*12+7
|
||||||
|
xq(is:is+11)=bitseq(2*i+1)*pp
|
||||||
|
enddo
|
||||||
|
xq(864-5:864)=bitseq(1)*pp(1:6) !last half symbol
|
||||||
|
do i=1,72
|
||||||
|
is=(i-1)*12+1
|
||||||
|
xi(is:is+11)=bitseq(2*i)*pp
|
||||||
|
enddo
|
||||||
|
! Map I and Q to tones.
|
||||||
|
i4tone=0
|
||||||
|
do i=1,72
|
||||||
|
i4tone(2*i-1)=(bitseq(2*i)*bitseq(2*i-1)+1)/2;
|
||||||
|
i4tone(2*i)=-(bitseq(2*i)*bitseq(mod(2*i,144)+1)-1)/2;
|
||||||
|
enddo
|
||||||
|
endif
|
||||||
|
|
||||||
|
! Flip polarity
|
||||||
|
i4tone=-i4tone+1
|
||||||
|
|
||||||
|
999 return
|
||||||
|
end subroutine genmsk_128_90
|
||||||
@ -1,132 +1,134 @@
|
|||||||
program ldpcsim
|
program ldpcsim128_90
|
||||||
|
|
||||||
use packjt
|
! Simulate the performance of the (128,90) code that is used in
|
||||||
integer, parameter:: NRECENT=10, N=128, K=90, M=N-K
|
! the second incarnation of MSK144.
|
||||||
character*12 recent_calls(NRECENT)
|
|
||||||
character*22 msg,msgsent,msgreceived
|
|
||||||
character*96 tmpchar
|
|
||||||
character*8 arg
|
|
||||||
integer*1 codeword(N), message77(77)
|
|
||||||
integer*1 apmask(N),cw(N)
|
|
||||||
integer*1 msgbits(77)
|
|
||||||
integer*4 i4Msg6BitWords(13)
|
|
||||||
integer nerrtot(0:N),nerrdec(0:N)
|
|
||||||
real*8 rxdata(N), rxavgd(N)
|
|
||||||
real llr(N)
|
|
||||||
|
|
||||||
do i=1,NRECENT
|
use packjt77
|
||||||
recent_calls(i)=' '
|
integer, parameter:: NRECENT=10, N=128, K=90, M=N-K
|
||||||
enddo
|
character*12 recent_calls(NRECENT)
|
||||||
nerrtot=0
|
character*37 msg,msgsent,msgreceived
|
||||||
nerrdec=0
|
character*77 c77
|
||||||
|
character*8 arg
|
||||||
|
integer*1 codeword(N), message77(77)
|
||||||
|
integer*1 apmask(N),cw(N)
|
||||||
|
integer*1 msgbits(77)
|
||||||
|
integer*4 i4Msg6BitWords(13)
|
||||||
|
integer nerrtot(0:N),nerrdec(0:N)
|
||||||
|
real*8 rxdata(N), rxavgd(N)
|
||||||
|
real llr(N)
|
||||||
|
|
||||||
nargs=iargc()
|
do i=1,NRECENT
|
||||||
if(nargs.ne.4) then
|
recent_calls(i)=' '
|
||||||
print*,'Usage: ldpcsim niter navg #trials s '
|
enddo
|
||||||
print*,'eg: ldpcsim 10 1 1000 0.75'
|
nerrtot=0
|
||||||
return
|
nerrdec=0
|
||||||
endif
|
|
||||||
call getarg(1,arg)
|
|
||||||
read(arg,*) max_iterations
|
|
||||||
call getarg(2,arg)
|
|
||||||
read(arg,*) navg
|
|
||||||
call getarg(3,arg)
|
|
||||||
read(arg,*) ntrials
|
|
||||||
call getarg(4,arg)
|
|
||||||
read(arg,*) s
|
|
||||||
|
|
||||||
rate=real(K)/real(N)
|
nargs=iargc()
|
||||||
|
if(nargs.ne.4) then
|
||||||
|
print*,'Usage: ldpcsim niter navg #trials s '
|
||||||
|
print*,'eg: ldpcsim 10 1 1000 0.75'
|
||||||
|
return
|
||||||
|
endif
|
||||||
|
call getarg(1,arg)
|
||||||
|
read(arg,*) max_iterations
|
||||||
|
call getarg(2,arg)
|
||||||
|
read(arg,*) navg
|
||||||
|
call getarg(3,arg)
|
||||||
|
read(arg,*) ntrials
|
||||||
|
call getarg(4,arg)
|
||||||
|
read(arg,*) s
|
||||||
|
|
||||||
write(*,*) "rate: ",rate
|
rate=real(77)/real(N)
|
||||||
write(*,*) "niter= ",max_iterations," navg= ",navg," s= ",s
|
|
||||||
|
write(*,*) "rate: ",rate
|
||||||
|
write(*,*) "niter= ",max_iterations," navg= ",navg," s= ",s
|
||||||
|
|
||||||
|
msg="K1ABC RR73; W9XYZ <KH1/KH7Z> -12"
|
||||||
|
i3=0
|
||||||
|
n3=1
|
||||||
|
call pack77(msg,i3,n3,c77)
|
||||||
|
call unpack77(c77,msgsent)
|
||||||
|
read(c77,'(77i1)') msgbits
|
||||||
|
|
||||||
!msg="K9AN K1JT EN50"
|
|
||||||
msg="G4WJS K1JT FN20"
|
|
||||||
call packmsg(msg,i4Msg6BitWords,itype,.false.) !Pack into 12 6-bit bytes
|
|
||||||
call unpackmsg(i4Msg6BitWords,msgsent,.false.,' ') !Unpack to get msgsent
|
|
||||||
write(*,*) "message sent ",msgsent
|
write(*,*) "message sent ",msgsent
|
||||||
|
|
||||||
tmpchar=' '
|
|
||||||
write(tmpchar,'(12b6.6)') i4Msg6BitWords(1:12)
|
|
||||||
tmpchar(73:77)="00000" !i5bit
|
|
||||||
read(tmpchar,'(77i1)') msgbits(1:77)
|
|
||||||
|
|
||||||
write(*,*) 'msgbits'
|
write(*,*) 'msgbits'
|
||||||
write(*,'(28i1,1x,28i1,1x,16i1,1x,5i1)') msgbits
|
write(*,'(77i1)') msgbits
|
||||||
|
|
||||||
! msgbits is the 77-bit message, codeword is 128 bits
|
! msgbits is the 77-bit message, codeword is 128 bits
|
||||||
call encode128_90(msgbits,codeword)
|
call encode_128_90(msgbits,codeword)
|
||||||
|
|
||||||
call init_random_seed()
|
! call init_random_seed()
|
||||||
|
|
||||||
write(*,*) "Eb/N0 SNR2500 ngood nundetected sigma psymerr"
|
write(*,*) "Eb/N0 SNR2500 ngood nundetected sigma psymerr"
|
||||||
do idb = 14,-6,-1
|
do idb = 14,0,-1
|
||||||
db=idb/2.0-1.0
|
db=idb/2.0-1.0
|
||||||
sigma=1/sqrt( 2*rate*(10**(db/10.0)) )
|
sigma=1/sqrt( 2*rate*(10**(db/10.0)) )
|
||||||
ngood=0
|
ngood=0
|
||||||
nue=0
|
nue=0
|
||||||
nbadcrc=0
|
nbadcrc=0
|
||||||
nsumerr=0
|
nsumerr=0
|
||||||
|
|
||||||
do itrial=1, ntrials
|
do itrial=1, ntrials
|
||||||
rxavgd=0d0
|
rxavgd=0d0
|
||||||
do iav=1,navg
|
do iav=1,navg
|
||||||
call sgran()
|
! call sgran()
|
||||||
! Create a realization of a noisy received word
|
! Create a realization of a noisy received word
|
||||||
do i=1,N
|
do i=1,N
|
||||||
rxdata(i) = 2.0*codeword(i)-1.0 + sigma*gran()
|
rxdata(i) = 2.0*codeword(i)-1.0 + sigma*gran()
|
||||||
|
enddo
|
||||||
|
rxavgd=rxavgd+rxdata
|
||||||
enddo
|
enddo
|
||||||
rxavgd=rxavgd+rxdata
|
rxdata=rxavgd
|
||||||
enddo
|
nerr=0
|
||||||
rxdata=rxavgd
|
do i=1,N
|
||||||
nerr=0
|
if( rxdata(i)*(2*codeword(i)-1.0) .lt. 0 ) nerr=nerr+1
|
||||||
do i=1,N
|
enddo
|
||||||
if( rxdata(i)*(2*codeword(i)-1.0) .lt. 0 ) nerr=nerr+1
|
nerrtot(nerr)=nerrtot(nerr)+1
|
||||||
enddo
|
|
||||||
nerrtot(nerr)=nerrtot(nerr)+1
|
|
||||||
|
|
||||||
rxav=sum(rxdata)/N
|
rxav=sum(rxdata)/N
|
||||||
rx2av=sum(rxdata*rxdata)/N
|
rx2av=sum(rxdata*rxdata)/N
|
||||||
rxsig=sqrt(rx2av-rxav*rxav)
|
rxsig=sqrt(rx2av-rxav*rxav)
|
||||||
rxdata=rxdata/rxsig
|
rxdata=rxdata/rxsig
|
||||||
! The s parameter can be tuned to trade a few tenth's dB of threshold for an order of
|
! The s parameter can be tuned to trade a few tenth's dB of threshold for an order of
|
||||||
! magnitude in UER
|
! magnitude in UER
|
||||||
if( s .lt. 0 ) then
|
if( s .lt. 0 ) then
|
||||||
ss=sigma
|
ss=sigma
|
||||||
else
|
else
|
||||||
ss=s
|
ss=s
|
||||||
endif
|
endif
|
||||||
|
|
||||||
llr=2.0*rxdata/(ss*ss)
|
llr=2.0*rxdata/(ss*ss)
|
||||||
|
|
||||||
apmask=0
|
apmask=0
|
||||||
! max_iterations is max number of belief propagation iterations
|
! max_iterations is max number of belief propagation iterations
|
||||||
call bpdecode128_90(llr, apmask, max_iterations, message77, cw, nharderrors, niterations)
|
call bpdecode128_90(llr, apmask, max_iterations, message77, cw, nharderrors, niterations)
|
||||||
|
|
||||||
! If the decoder finds a valid codeword, nharderrors will be .ge. 0.
|
! If the decoder finds a valid codeword, nharderrors will be .ge. 0.
|
||||||
if( nharderrors .ge. 0 ) then
|
if( nharderrors .ge. 0 ) then
|
||||||
call extractmessage77(message77,msgreceived)
|
write(c77,'(77i1)') message77
|
||||||
nhw=count(cw.ne.codeword)
|
call unpack77(c77,msgreceived)
|
||||||
if(nhw.eq.0) then ! this is a good decode
|
nhw=count(cw.ne.codeword)
|
||||||
|
if(nhw.eq.0) then ! this is a good decode
|
||||||
ngood=ngood+1
|
ngood=ngood+1
|
||||||
nerrdec(nerr)=nerrdec(nerr)+1
|
nerrdec(nerr)=nerrdec(nerr)+1
|
||||||
else ! this is an undetected error
|
else ! this is an undetected error
|
||||||
nue=nue+1
|
nue=nue+1
|
||||||
endif
|
endif
|
||||||
endif
|
endif
|
||||||
nsumerr=nsumerr+nerr
|
nsumerr=nsumerr+nerr
|
||||||
|
enddo
|
||||||
|
|
||||||
|
snr2500=db+10*log10(rate*2000.0/2500.0) ! symbol rate is 2000 s^-1 and ref BW is 2500 Hz.
|
||||||
|
pberr=real(nsumerr)/real(ntrials*N)
|
||||||
|
write(*,"(f4.1,4x,f5.1,1x,i8,1x,i8,7x,f5.2,3x,e10.3)") db,snr2500,ngood,nue,ss,pberr
|
||||||
|
|
||||||
enddo
|
enddo
|
||||||
|
|
||||||
snr2500=db-2.5
|
open(unit=23,file='nerrhisto.dat',status='unknown')
|
||||||
pberr=real(nsumerr)/real(ntrials*N)
|
do i=0,N
|
||||||
write(*,"(f4.1,4x,f5.1,1x,i8,1x,i8,7x,f5.2,3x,e10.3)") db,snr2500,ngood,nue,ss,pberr
|
write(23,'(i4,2x,i10,i10,f10.2)') i,nerrdec(i),nerrtot(i),real(nerrdec(i))/real(nerrtot(i)+1e-10)
|
||||||
|
enddo
|
||||||
enddo
|
close(23)
|
||||||
|
|
||||||
open(unit=23,file='nerrhisto.dat',status='unknown')
|
end program ldpcsim128_90
|
||||||
do i=0,N
|
|
||||||
write(23,'(i4,2x,i10,i10,f10.2)') i,nerrdec(i),nerrtot(i),real(nerrdec(i))/real(nerrtot(i)+1e-10)
|
|
||||||
enddo
|
|
||||||
close(23)
|
|
||||||
|
|
||||||
end program ldpcsim
|
|
||||||
|
|||||||
@ -41,7 +41,7 @@ call getarg(4,arg)
|
|||||||
read(arg,*) s
|
read(arg,*) s
|
||||||
|
|
||||||
! don't count hash bits as data bits
|
! don't count hash bits as data bits
|
||||||
K=80
|
K=72
|
||||||
N=128
|
N=128
|
||||||
rate=real(K)/real(N)
|
rate=real(K)/real(N)
|
||||||
|
|
||||||
@ -161,7 +161,7 @@ do idb = 14,-6,-1
|
|||||||
endif
|
endif
|
||||||
endif
|
endif
|
||||||
enddo
|
enddo
|
||||||
snr2500=db-3.0
|
snr2500=db-3.5
|
||||||
write(*,"(f4.1,4x,f5.1,1x,i8,1x,i8,1x,i8,8x,f5.2)") db,snr2500,ngood,nue,nbadhash,ss
|
write(*,"(f4.1,4x,f5.1,1x,i8,1x,i8,1x,i8,8x,f5.2)") db,snr2500,ngood,nue,nbadhash,ss
|
||||||
|
|
||||||
enddo
|
enddo
|
||||||
|
|||||||
Loading…
Reference in New Issue
Block a user