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Fix some bugs in simulators, add pre-processing rules to osd300.f90. 

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@8426 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
This commit is contained in:
Steven Franke 2018-01-20 18:45:40 +00:00
parent 21faf3a9ad
commit affa853609
4 changed files with 262 additions and 78 deletions
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30
lib/fsk4hf/ldpcsim300.f90
View File

@ -47,17 +47,19 @@ nerrdec=0
nmpcbad=0 ! Used to collect the number of errors in the message+crc part of the codeword
nargs=iargc()
if(nargs.ne.3) then
print*,'Usage: ldpcsim niter #trials s '
print*,'eg: ldpcsim 100 1000 0.84'
if(nargs.ne.4) then
print*,'Usage: ldpcsim niter ndeep #trials s '
print*,'eg: ldpcsim 100 4 1000 0.84'
print*,'If s is negative, then value is ignored and sigma is calculated from SNR.'
return
endif
call getarg(1,arg)
read(arg,*) max_iterations
call getarg(2,arg)
read(arg,*) ntrials
read(arg,*) ndeep
call getarg(3,arg)
read(arg,*) ntrials
call getarg(4,arg)
read(arg,*) s
fsk=.false.
@ -147,14 +149,14 @@ do idb = 20,-16,-1
do i=1,N
if( rxdata(i)*(2*codeword(i)-1.0) .lt. 0 ) nerr=nerr+1
enddo
nerrtot(nerr)=nerrtot(nerr)+1
if(nerr.ge.1) nerrtot(nerr)=nerrtot(nerr)+1
nberr=nberr+nerr
! Correct signal normalization is important for this decoder.
! rxav=sum(rxdata)/N
! rx2av=sum(rxdata*rxdata)/N
! rxsig=sqrt(rx2av-rxav*rxav)
! rxdata=rxdata/rxsig
rxav=sum(rxdata)/N
rx2av=sum(rxdata*rxdata)/N
rxsig=sqrt(rx2av-rxav*rxav)
rxdata=rxdata/rxsig
! To match the metric to the channel, s should be set to the noise standard deviation.
! For now, set s to the value that optimizes decode probability near threshold.
! The s parameter can be tuned to trade a few tenth's dB of threshold for an order of
@ -169,9 +171,9 @@ do idb = 20,-16,-1
apmask=0
! max_iterations is max number of belief propagation iterations
call bpdecode300(llr, apmask, max_iterations, decoded, niterations, cw)
if( niterations .lt. 0 ) then
norder=3
call osd300(llr, norder, decoded, niterations, cw)
if( (niterations .lt. 0) .and. (ndeep .ge. 0) ) then
call osd300(llr, apmask, ndeep, decoded, cw, nhardmin, dmin)
niterations=nhardmin
endif
n2err=0
do i=1,N
@ -221,10 +223,10 @@ do idb = 20,-16,-1
nerrmpc=nerrmpc+1
endif
enddo
nmpcbad(nerrmpc)=nmpcbad(nerrmpc)+1 ! This histogram should inform our selection of CRC poly
if(nerrmpc.ge.1) nmpcbad(nerrmpc)=nmpcbad(nerrmpc)+1 ! This histogram should inform our selection of CRC poly
if( ncrcflag .eq. 1 .and. nueflag .eq. 0 ) then
ngood=ngood+1
nerrdec(nerr)=nerrdec(nerr)+1
if(nerr.ge.1) nerrdec(nerr)=nerrdec(nerr)+1
else if( ncrcflag .eq. 1 .and. nueflag .eq. 1 ) then
nue=nue+1;
endif

297
lib/fsk4hf/osd300.f90
View File

@ -1,30 +1,31 @@
subroutine osd300(llr,norder,decoded,niterations,cw)
subroutine osd300(llr,apmask,ndeep,decoded,cw,nhardmin,dmin)
!
! An ordered-statistics decoder for the (300,60) code.
!
!
include "ldpc_300_60_params.f90"
integer*1 apmask(N),apmaskr(N)
integer*1 gen(K,N)
integer*1 genmrb(K,N),g2(N,K)
integer*1 temp(K),m0(K),me(K),mi(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 indices(N),nxor(N)
integer*1 cw(N),ce(N),c0(N),hdec(N)
integer*1 decoded(K)
integer indx(N)
real llr(N),rx(N),absrx(N)
logical first
logical first,reset
data first/.true./
save first,gen
if( first ) then ! fill the generator matrix
gen=0
do i=1,M
do j=1,15
do j=1, 15
read(g(i)(j:j),"(Z1)") istr
do jj=1, 4
irow=(j-1)*4+jj
if( btest(istr,4-jj) ) gen(irow,i)=1
if( btest(istr,4-jj) ) gen(irow,i)=1
enddo
enddo
enddo
@ -34,28 +35,26 @@ if( first ) then ! fill the generator matrix
first=.false.
endif
! re-order received vector to place systematic msg bits at the end
! Re-order received vector to place systematic msg bits at the end.
rx=llr(colorder+1)
apmaskr=apmask(colorder+1)
! hard decode the received word
! Hard decisions on the received word.
hdec=0
where(rx .ge. 0) hdec=1
! use magnitude of received symbols as a measure of reliability.
! 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.
! 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
! 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).
! reliability will not be strictly decreasing because column re-ordering is needed
! to put the generator matrix in systematic form. the "indices" array tracks
! column permutations caused by reliability sorting and gaussian elimination.
do id=1,K ! diagonal element indices
do icol=id,K+20 ! The 20 is ad hoc - beware
iflag=0
@ -71,7 +70,7 @@ do id=1,K ! diagonal element indices
endif
do ii=1,K
if( ii .ne. id .and. genmrb(ii,id) .eq. 1 ) then
genmrb(ii,1:N)=mod(genmrb(ii,1:N)+genmrb(id,1:N),2)
genmrb(ii,1:N)=ieor(genmrb(ii,1:N),genmrb(id,1:N))
endif
enddo
exit
@ -84,66 +83,168 @@ 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. Test all such codewords against the received word to decide which
! codeword is most likely to be correct.
! 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)
s1=sum(absrx(1:K))
s2=sum(absrx(K+1:N))
xlam=5.0
rho=s1/(s1+xlam*s2)
call mrbencode(m0,c0,g2,N,K)
nxor=ieor(c0,hdec)
nhardmin=sum(nxor)
dmin=sum(nxor*absrx)
thresh=rho*dmin
cw=c0
nt=0
ntotal=0
nrejected=0
do iorder=1,norder
mi(1:K-iorder)=0
mi(K-iorder+1:K)=1
iflag=0
do while(iflag .ge. 0 )
dpat=sum(mi*absrx(1:K))
nt=nt+1
if( dpat .lt. thresh ) then ! reject unlikely error patterns
me=ieor(m0,mi)
call mrbencode(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)
thresh=rho*dmin
if(ndeep.eq.0) goto 998 ! norder=0
if(ndeep.gt.5) ndeep=5
if( ndeep.eq. 1) then
nord=1
npre1=0
npre2=0
nt=120
ntheta=12
elseif(ndeep.eq.2) then
nord=1
npre1=1
npre2=0
nt=120
ntheta=12
elseif(ndeep.eq.3) then
nord=1
npre1=1
npre2=1
nt=120
ntheta=12
ntau=15
elseif(ndeep.eq.4) then
nord=2
npre1=1
npre2=0
nt=120
ntheta=12
ntau=15
elseif(ndeep.eq.5) then
nord=4
npre1=1
npre2=1
nt=120
ntheta=20
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
else
nrejected=nrejected+1
endif
! get the next test error pattern, iflag will go negative
! when the last pattern with weight iorder has been generated
call nextpat(mi,k,iorder,iflag)
enddo
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 mrbencode(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 mrbencode(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 nextpat(misub,k,iorder,iflag)
enddo
enddo
!write(*,*) 'nhardmin ',nhardmin
!write(*,*) 'total patterns ',nt,' number rejected ',nrejected
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 boxit(reset,mi(1:ntau),ntau,ntotal,i1,i2)
enddo
enddo
! re-order the codeword to place message bits at the end
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 mrbencode(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 fetchit(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 mrbencode(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 nextpat(misub,K,nord,iflag)
enddo
endif
998 continue
! Re-order the codeword to place message bits at the end.
cw(indices)=cw
hdec(indices)=hdec
decoded=cw(M+1:N)
nerr=0
do i=1,N
if( hdec(i) .ne. cw(i) ) nerr=nerr+1
enddo
niterations=nerr
decoded=cw(M+1:N)
cw(colorder+1)=cw ! put the codeword back into received-word order
return
end subroutine osd300
@ -179,6 +280,86 @@ subroutine nextpat(mi,k,iorder,iflag)
ms(k-nz+1:k)=1
endif
mi=ms
iflag=ind
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 nextpat
subroutine boxit(reset,e2,ntau,npindex,i1,i2)
integer*1 e2(1:ntau)
integer indexes(4000,2),fp(0:525000),np(4000)
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 boxit
subroutine fetchit(reset,e2,ntau,i1,i2)
integer indexes(4000,2),fp(0:525000),np(4000)
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 fetchit

9
lib/ft8/ldpcsim174.f90
View File

@ -7,6 +7,7 @@ parameter(NRECENT=10)
character*12 recent_calls(NRECENT)
character*22 msg,msgsent,msgreceived
character*8 arg
character*6 grid
integer*1, allocatable :: codeword(:), decoded(:), message(:)
integer*1, target:: i1Msg8BitBytes(11)
integer*1 msgbits(87)
@ -72,7 +73,7 @@ allocate ( rxdata(N), llr(N) )
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.,'') !Unpack to get msgsent
call unpackmsg(i4Msg6BitWords,msgsent,.false.,grid) !Unpack to get msgsent
write(*,*) "message sent ",msgsent
i4=0
@ -164,7 +165,7 @@ do idb = 20,-10,-1
do i=1,N
if( rxdata(i)*(2*codeword(i)-1.0) .lt. 0 ) nerr=nerr+1
enddo
nerrtot(nerr)=nerrtot(nerr)+1
if(nerr.ge.1) nerrtot(nerr)=nerrtot(nerr)+1
nberr=nberr+nerr
! Correct signal normalization is important for this decoder.
@ -206,11 +207,11 @@ do idb = 20,-10,-1
nerrmpc=nerrmpc+1
endif
enddo
nmpcbad(nerrmpc)=nmpcbad(nerrmpc)+1
if(nerrmpc.ge.1) nmpcbad(nerrmpc)=nmpcbad(nerrmpc)+1
if( ncrcflag .eq. 1 ) then
if( nueflag .eq. 0 ) then
ngood=ngood+1
nerrdec(nerr)=nerrdec(nerr)+1
if(nerr.ge.1) nerrdec(nerr)=nerrdec(nerr)+1
else if( nueflag .eq. 1 ) then
nue=nue+1;
endif

4
lib/ft8/osd174.f90
View File

@ -25,7 +25,7 @@ if( first ) then ! fill the generator matrix
read(g(i)(j:j),"(Z1)") istr
do jj=1, 4
irow=(j-1)*4+jj
if( btest(istr,4-jj) ) gen(irow,i)=1
if( btest(istr,4-jj) ) gen(irow,i)=1
enddo
enddo
enddo
@ -255,7 +255,7 @@ endif
! Re-order the codeword to place message bits at the end.
cw(indices)=cw
hdec(indices)=hdec
decoded=cw(K+1:N)
decoded=cw(M+1:N)
cw(colorder+1)=cw ! put the codeword back into received-word order
return
end subroutine osd174