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https://github.com/saitohirga/WSJT-X.git
synced 2025-10-31 04:50:34 -04:00
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
parent
21faf3a9ad
commit
affa853609
@ -47,17 +47,19 @@ nerrdec=0
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nmpcbad=0 ! Used to collect the number of errors in the message+crc part of the codeword
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nargs=iargc()
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if(nargs.ne.3) then
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print*,'Usage: ldpcsim niter #trials s '
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print*,'eg: ldpcsim 100 1000 0.84'
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if(nargs.ne.4) then
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print*,'Usage: ldpcsim niter ndeep #trials s '
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print*,'eg: ldpcsim 100 4 1000 0.84'
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print*,'If s is negative, then value is ignored and sigma is calculated from SNR.'
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return
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endif
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call getarg(1,arg)
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read(arg,*) max_iterations
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call getarg(2,arg)
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read(arg,*) ntrials
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read(arg,*) ndeep
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call getarg(3,arg)
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read(arg,*) ntrials
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call getarg(4,arg)
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read(arg,*) s
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fsk=.false.
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@ -147,14 +149,14 @@ do idb = 20,-16,-1
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do i=1,N
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if( rxdata(i)*(2*codeword(i)-1.0) .lt. 0 ) nerr=nerr+1
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enddo
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nerrtot(nerr)=nerrtot(nerr)+1
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if(nerr.ge.1) nerrtot(nerr)=nerrtot(nerr)+1
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nberr=nberr+nerr
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! Correct signal normalization is important for this decoder.
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! rxav=sum(rxdata)/N
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! rx2av=sum(rxdata*rxdata)/N
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! rxsig=sqrt(rx2av-rxav*rxav)
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! rxdata=rxdata/rxsig
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rxav=sum(rxdata)/N
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rx2av=sum(rxdata*rxdata)/N
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rxsig=sqrt(rx2av-rxav*rxav)
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rxdata=rxdata/rxsig
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! To match the metric to the channel, s should be set to the noise standard deviation.
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! For now, set s to the value that optimizes decode probability near threshold.
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! The s parameter can be tuned to trade a few tenth's dB of threshold for an order of
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@ -169,9 +171,9 @@ do idb = 20,-16,-1
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apmask=0
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! max_iterations is max number of belief propagation iterations
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call bpdecode300(llr, apmask, max_iterations, decoded, niterations, cw)
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if( niterations .lt. 0 ) then
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norder=3
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call osd300(llr, norder, decoded, niterations, cw)
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if( (niterations .lt. 0) .and. (ndeep .ge. 0) ) then
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call osd300(llr, apmask, ndeep, decoded, cw, nhardmin, dmin)
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niterations=nhardmin
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endif
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n2err=0
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do i=1,N
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@ -221,10 +223,10 @@ do idb = 20,-16,-1
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nerrmpc=nerrmpc+1
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endif
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enddo
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nmpcbad(nerrmpc)=nmpcbad(nerrmpc)+1 ! This histogram should inform our selection of CRC poly
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if(nerrmpc.ge.1) nmpcbad(nerrmpc)=nmpcbad(nerrmpc)+1 ! This histogram should inform our selection of CRC poly
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if( ncrcflag .eq. 1 .and. nueflag .eq. 0 ) then
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ngood=ngood+1
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nerrdec(nerr)=nerrdec(nerr)+1
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if(nerr.ge.1) nerrdec(nerr)=nerrdec(nerr)+1
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else if( ncrcflag .eq. 1 .and. nueflag .eq. 1 ) then
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nue=nue+1;
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endif
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@ -1,30 +1,31 @@
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subroutine osd300(llr,norder,decoded,niterations,cw)
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subroutine osd300(llr,apmask,ndeep,decoded,cw,nhardmin,dmin)
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!
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! An ordered-statistics decoder for the (300,60) code.
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!
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!
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include "ldpc_300_60_params.f90"
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integer*1 apmask(N),apmaskr(N)
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integer*1 gen(K,N)
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integer*1 genmrb(K,N),g2(N,K)
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integer*1 temp(K),m0(K),me(K),mi(K)
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integer*1 temp(K),m0(K),me(K),mi(K),misub(K),e2sub(N-K),e2(N-K),ui(N-K)
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integer*1 r2pat(N-K)
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integer indices(N),nxor(N)
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integer*1 cw(N),ce(N),c0(N),hdec(N)
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integer*1 decoded(K)
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integer indx(N)
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real llr(N),rx(N),absrx(N)
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logical first
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logical first,reset
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data first/.true./
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save first,gen
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if( first ) then ! fill the generator matrix
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gen=0
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do i=1,M
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do j=1,15
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do j=1, 15
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read(g(i)(j:j),"(Z1)") istr
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do jj=1, 4
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irow=(j-1)*4+jj
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if( btest(istr,4-jj) ) gen(irow,i)=1
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if( btest(istr,4-jj) ) gen(irow,i)=1
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enddo
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enddo
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enddo
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@ -34,28 +35,26 @@ if( first ) then ! fill the generator matrix
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first=.false.
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endif
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! re-order received vector to place systematic msg bits at the end
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! Re-order received vector to place systematic msg bits at the end.
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rx=llr(colorder+1)
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apmaskr=apmask(colorder+1)
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! hard decode the received word
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! Hard decisions on the received word.
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hdec=0
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where(rx .ge. 0) hdec=1
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! use magnitude of received symbols as a measure of reliability.
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! Use magnitude of received symbols as a measure of reliability.
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absrx=abs(rx)
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call indexx(absrx,N,indx)
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! re-order the columns of the generator matrix in order of decreasing reliability.
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! Re-order the columns of the generator matrix in order of decreasing reliability.
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do i=1,N
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genmrb(1:K,i)=gen(1:K,indx(N+1-i))
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indices(i)=indx(N+1-i)
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enddo
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! do gaussian elimination to create a generator matrix with the most reliable
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! Do gaussian elimination to create a generator matrix with the most reliable
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! received bits in positions 1:K in order of decreasing reliability (more or less).
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! reliability will not be strictly decreasing because column re-ordering is needed
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! to put the generator matrix in systematic form. the "indices" array tracks
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! column permutations caused by reliability sorting and gaussian elimination.
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do id=1,K ! diagonal element indices
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do icol=id,K+20 ! The 20 is ad hoc - beware
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iflag=0
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@ -71,7 +70,7 @@ do id=1,K ! diagonal element indices
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endif
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do ii=1,K
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if( ii .ne. id .and. genmrb(ii,id) .eq. 1 ) then
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genmrb(ii,1:N)=mod(genmrb(ii,1:N)+genmrb(id,1:N),2)
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genmrb(ii,1:N)=ieor(genmrb(ii,1:N),genmrb(id,1:N))
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endif
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enddo
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exit
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@ -84,66 +83,168 @@ g2=transpose(genmrb)
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! The hard decisions for the K MRB bits define the order 0 message, m0.
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! Encode m0 using the modified generator matrix to find the "order 0" codeword.
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! Flip various combinations of bits in m0 and re-encode to generate a list of
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! codewords. Test all such codewords against the received word to decide which
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! codeword is most likely to be correct.
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! codewords. Return the member of the list that has the smallest Euclidean
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! distance to the received word.
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hdec=hdec(indices) ! hard decisions from received symbols
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m0=hdec(1:K) ! zero'th order message
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absrx=absrx(indices)
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rx=rx(indices)
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apmaskr=apmaskr(indices)
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s1=sum(absrx(1:K))
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s2=sum(absrx(K+1:N))
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xlam=5.0
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rho=s1/(s1+xlam*s2)
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call mrbencode(m0,c0,g2,N,K)
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nxor=ieor(c0,hdec)
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nhardmin=sum(nxor)
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dmin=sum(nxor*absrx)
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thresh=rho*dmin
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cw=c0
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nt=0
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ntotal=0
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nrejected=0
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do iorder=1,norder
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mi(1:K-iorder)=0
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mi(K-iorder+1:K)=1
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iflag=0
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do while(iflag .ge. 0 )
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dpat=sum(mi*absrx(1:K))
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nt=nt+1
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if( dpat .lt. thresh ) then ! reject unlikely error patterns
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me=ieor(m0,mi)
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call mrbencode(me,ce,g2,N,K)
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nxor=ieor(ce,hdec)
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dd=sum(nxor*absrx)
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if( dd .lt. dmin ) then
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dmin=dd
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cw=ce
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nhardmin=sum(nxor)
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thresh=rho*dmin
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if(ndeep.eq.0) goto 998 ! norder=0
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if(ndeep.gt.5) ndeep=5
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if( ndeep.eq. 1) then
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nord=1
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npre1=0
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npre2=0
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nt=120
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ntheta=12
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elseif(ndeep.eq.2) then
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nord=1
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npre1=1
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npre2=0
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nt=120
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ntheta=12
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elseif(ndeep.eq.3) then
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nord=1
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npre1=1
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npre2=1
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nt=120
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ntheta=12
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ntau=15
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elseif(ndeep.eq.4) then
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nord=2
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npre1=1
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npre2=0
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nt=120
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ntheta=12
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ntau=15
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elseif(ndeep.eq.5) then
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nord=4
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npre1=1
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npre2=1
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nt=120
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ntheta=20
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ntau=15
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endif
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do iorder=1,nord
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misub(1:K-iorder)=0
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misub(K-iorder+1:K)=1
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iflag=K-iorder+1
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do while(iflag .ge.0)
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if(iorder.eq.nord .and. npre1.eq.0) then
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iend=iflag
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else
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iend=1
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endif
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else
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nrejected=nrejected+1
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endif
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! get the next test error pattern, iflag will go negative
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! when the last pattern with weight iorder has been generated
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call nextpat(mi,k,iorder,iflag)
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enddo
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do n1=iflag,iend,-1
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mi=misub
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mi(n1)=1
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if(any(iand(apmaskr(1:K),mi).eq.1)) cycle
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ntotal=ntotal+1
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me=ieor(m0,mi)
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if(n1.eq.iflag) then
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call mrbencode(me,ce,g2,N,K)
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e2sub=ieor(ce(K+1:N),hdec(K+1:N))
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e2=e2sub
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nd1Kpt=sum(e2sub(1:nt))+1
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d1=sum(ieor(me(1:K),hdec(1:K))*absrx(1:K))
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else
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e2=ieor(e2sub,g2(K+1:N,n1))
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nd1Kpt=sum(e2(1:nt))+2
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endif
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if(nd1Kpt .le. ntheta) then
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call mrbencode(me,ce,g2,N,K)
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nxor=ieor(ce,hdec)
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if(n1.eq.iflag) then
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dd=d1+sum(e2sub*absrx(K+1:N))
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else
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dd=d1+ieor(ce(n1),hdec(n1))*absrx(n1)+sum(e2*absrx(K+1:N))
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endif
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if( dd .lt. dmin ) then
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dmin=dd
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cw=ce
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nhardmin=sum(nxor)
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nd1Kptbest=nd1Kpt
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endif
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else
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nrejected=nrejected+1
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endif
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enddo
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! Get the next test error pattern, iflag will go negative
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! when the last pattern with weight iorder has been generated.
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call nextpat(misub,k,iorder,iflag)
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enddo
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enddo
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!write(*,*) 'nhardmin ',nhardmin
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!write(*,*) 'total patterns ',nt,' number rejected ',nrejected
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if(npre2.eq.1) then
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reset=.true.
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ntotal=0
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do i1=K,1,-1
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do i2=i1-1,1,-1
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ntotal=ntotal+1
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mi(1:ntau)=ieor(g2(K+1:K+ntau,i1),g2(K+1:K+ntau,i2))
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call boxit(reset,mi(1:ntau),ntau,ntotal,i1,i2)
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enddo
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enddo
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! re-order the codeword to place message bits at the end
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ncount2=0
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ntotal2=0
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reset=.true.
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! Now run through again and do the second pre-processing rule
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misub(1:K-nord)=0
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misub(K-nord+1:K)=1
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iflag=K-nord+1
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do while(iflag .ge.0)
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me=ieor(m0,misub)
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call mrbencode(me,ce,g2,N,K)
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e2sub=ieor(ce(K+1:N),hdec(K+1:N))
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do i2=0,ntau
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ntotal2=ntotal2+1
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ui=0
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if(i2.gt.0) ui(i2)=1
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r2pat=ieor(e2sub,ui)
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778 continue
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call fetchit(reset,r2pat(1:ntau),ntau,in1,in2)
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if(in1.gt.0.and.in2.gt.0) then
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ncount2=ncount2+1
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mi=misub
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mi(in1)=1
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mi(in2)=1
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if(sum(mi).lt.nord+npre1+npre2.or.any(iand(apmaskr(1:K),mi).eq.1)) cycle
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me=ieor(m0,mi)
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call mrbencode(me,ce,g2,N,K)
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nxor=ieor(ce,hdec)
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dd=sum(nxor*absrx)
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if( dd .lt. dmin ) then
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dmin=dd
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cw=ce
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nhardmin=sum(nxor)
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endif
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goto 778
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endif
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enddo
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call nextpat(misub,K,nord,iflag)
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enddo
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endif
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998 continue
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! Re-order the codeword to place message bits at the end.
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cw(indices)=cw
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hdec(indices)=hdec
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decoded=cw(M+1:N)
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nerr=0
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do i=1,N
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if( hdec(i) .ne. cw(i) ) nerr=nerr+1
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enddo
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niterations=nerr
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decoded=cw(M+1:N)
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cw(colorder+1)=cw ! put the codeword back into received-word order
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return
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end subroutine osd300
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@ -179,6 +280,86 @@ subroutine nextpat(mi,k,iorder,iflag)
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ms(k-nz+1:k)=1
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endif
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mi=ms
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iflag=ind
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do i=1,k ! iflag will point to the lowest-index 1 in mi
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if(mi(i).eq.1) then
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iflag=i
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exit
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endif
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enddo
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return
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end subroutine nextpat
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subroutine boxit(reset,e2,ntau,npindex,i1,i2)
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integer*1 e2(1:ntau)
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integer indexes(4000,2),fp(0:525000),np(4000)
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logical reset
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common/boxes/indexes,fp,np
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if(reset) then
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patterns=-1
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fp=-1
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np=-1
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sc=-1
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indexes=-1
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reset=.false.
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endif
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indexes(npindex,1)=i1
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indexes(npindex,2)=i2
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ipat=0
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do i=1,ntau
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if(e2(i).eq.1) then
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ipat=ipat+ishft(1,ntau-i)
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endif
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enddo
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ip=fp(ipat) ! see what's currently stored in fp(ipat)
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if(ip.eq.-1) then
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fp(ipat)=npindex
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else
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do while (np(ip).ne.-1)
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ip=np(ip)
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enddo
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np(ip)=npindex
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endif
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return
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end subroutine boxit
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subroutine fetchit(reset,e2,ntau,i1,i2)
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integer indexes(4000,2),fp(0:525000),np(4000)
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integer lastpat
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integer*1 e2(ntau)
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logical reset
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common/boxes/indexes,fp,np
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save lastpat,inext
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if(reset) then
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lastpat=-1
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reset=.false.
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endif
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ipat=0
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do i=1,ntau
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if(e2(i).eq.1) then
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ipat=ipat+ishft(1,ntau-i)
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endif
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enddo
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index=fp(ipat)
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if(lastpat.ne.ipat .and. index.gt.0) then ! return first set of indices
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i1=indexes(index,1)
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i2=indexes(index,2)
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inext=np(index)
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elseif(lastpat.eq.ipat .and. inext.gt.0) then
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||||
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
|
||||
|
||||
|
||||
@ -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
|
||||
|
||||
@ -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
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user