mirror of https://github.com/saitohirga/WSJT-X.git
Implement coupled BP->OSD decoding for FT8/FT4.
This commit is contained in:
Steven Franke
parent
160a8c896c
commit
093c403063
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@ -428,6 +428,7 @@ set (wsjt_FSRCS
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lib/encode_128_90.f90
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lib/encode_128_90.f90
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lib/ft8/encode174.f90
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lib/ft8/encode174.f90
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lib/ft8/encode174_91.f90
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lib/ft8/encode174_91.f90
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lib/ft8/encode174_91_nocrc.f90
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lib/entail.f90
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lib/entail.f90
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lib/ephem.f90
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lib/ephem.f90
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lib/extract.f90
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lib/extract.f90
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@ -603,12 +604,14 @@ set (wsjt_FSRCS
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lib/fsk4hf/genwsprcpm.f90
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lib/fsk4hf/genwsprcpm.f90
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lib/fsk4hf/encode204.f90
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lib/fsk4hf/encode204.f90
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lib/fsk4hf/decode174_74.f90
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lib/fsk4hf/decode174_74.f90
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lib/ft8/decode174_91.f90
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lib/fsk4hf/decode240_101.f90
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lib/fsk4hf/decode240_101.f90
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lib/fsk4hf/decode280_101.f90
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lib/fsk4hf/decode280_101.f90
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lib/fsk4hf/ldpcsim174_91.f90
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lib/fsk4hf/ldpcsim174_91.f90
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lib/fsk4hf/ldpcsim174_74.f90
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lib/fsk4hf/ldpcsim174_74.f90
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lib/fsk4hf/ldpcsim240_101.f90
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lib/fsk4hf/ldpcsim240_101.f90
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lib/fsk4hf/ldpcsim280_101.f90
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lib/fsk4hf/ldpcsim280_101.f90
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lib/fsk4hf/get_crc14.f90
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lib/fsk4hf/get_crc24.f90
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lib/fsk4hf/get_crc24.f90
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lib/fsk4hf/encode174_74.f90
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lib/fsk4hf/encode174_74.f90
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lib/fsk4hf/encode240_101.f90
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lib/fsk4hf/encode240_101.f90
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@ -1,15 +1,19 @@
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subroutine get_crc14(mc,ncrc)
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subroutine get_crc14(mc,len,ncrc)
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!
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! 1. To calculate 14-bit CRC, mc(1:len-14) is the message and mc(len-13:len) are zero.
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! 2. To check a received CRC, mc(1:len is the received message plus CRC.
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! ncrc will be zero if the received message/CRC are consistent
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!
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character c14*14
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character c14*14
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integer*1 mc(len)
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integer*1 mc(68),r(15),p(15)
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integer*1 r(15),p(15)
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integer ncrc
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integer ncrc
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! polynomial for 14-bit CRC 0x6757
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! polynomial for 14-bit CRC 0x6757
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data p/1,1,0,0,1,1,1,0,1,0,1,0,1,1,1/
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data p/1,1,0,0,1,1,1,0,1,0,1,0,1,1,1/
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! divide by polynomial
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! divide by polynomial
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r=mc(1:15)
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r=mc(1:15)
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do i=0,53
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do i=0,len-15
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r(15)=mc(i+15)
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r(15)=mc(i+15)
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r=mod(r+r(1)*p,2)
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r=mod(r+r(1)*p,2)
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r=cshift(r,1)
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r=cshift(r,1)
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@ -17,6 +21,5 @@ subroutine get_crc14(mc,ncrc)
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write(c14,'(14b1)') r(1:14)
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write(c14,'(14b1)') r(1:14)
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read(c14,'(b14.14)') ncrc
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read(c14,'(b14.14)') ncrc
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! mc(55:68)=r(1:14)
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end subroutine get_crc14
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end subroutine get_crc14
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@ -10,7 +10,7 @@ character*6 grid
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character*96 tmpchar
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character*96 tmpchar
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integer*1, allocatable :: codeword(:), decoded(:), message(:)
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integer*1, allocatable :: codeword(:), decoded(:), message(:)
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integer*1 msgbits(77)
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integer*1 msgbits(77)
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integer*1 message77(77)
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integer*1 message77(77),message91(91)
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integer*1 apmask(N), cw(N)
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integer*1 apmask(N), cw(N)
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integer nerrtot(0:N),nerrdec(0:N)
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integer nerrtot(0:N),nerrdec(0:N)
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logical unpk77_success
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logical unpk77_success
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@ -21,11 +21,12 @@ nerrtot=0
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nerrdec=0
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nerrdec=0
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nargs=iargc()
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nargs=iargc()
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if(nargs.ne.4) then
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if(nargs.ne.6) then
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print*,'Usage: ldpcsim niter ndepth #trials s '
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print*,'Usage: ldpcsim niter ndepth #trials s Keff BPOSD'
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print*,'eg: ldpcsim 10 2 1000 0.84'
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print*,'eg: ldpcsim 10 2 1000 0.84 91 1'
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print*,'belief propagation iterations: niter, ordered-statistics depth: ndepth'
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print*,'belief propagation iterations: niter, ordered-statistics depth: ndepth'
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print*,'If s is negative, then value is ignored and sigma is calculated from SNR.'
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print*,'If s is negative, then value is ignored and sigma is calculated from SNR.'
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print*,'If BPOSD=0, no coupling. BPOSD=1, BP output to OSD input.'
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return
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return
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endif
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endif
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call getarg(1,arg)
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call getarg(1,arg)
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@ -36,9 +37,13 @@ call getarg(3,arg)
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read(arg,*) ntrials
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read(arg,*) ntrials
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call getarg(4,arg)
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call getarg(4,arg)
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read(arg,*) s
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read(arg,*) s
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call getarg(5,arg)
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read(arg,*) Keff
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call getarg(6,arg)
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read(arg,*) nbposd
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! scale Eb/No for a (174,91) code
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! scale Eb/No for a (174,91) code
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rate=real(K)/real(N)
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rate=real(Keff)/real(N)
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write(*,*) "rate: ",rate
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write(*,*) "rate: ",rate
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write(*,*) "niter= ",max_iterations," s= ",s
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write(*,*) "niter= ",max_iterations," s= ",s
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@ -46,8 +51,7 @@ write(*,*) "niter= ",max_iterations," s= ",s
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allocate ( codeword(N), decoded(K), message(K) )
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allocate ( codeword(N), decoded(K), message(K) )
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allocate ( rxdata(N), llr(N) )
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allocate ( rxdata(N), llr(N) )
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! msg="K1JT K9AN EN50"
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msg="K9ABC K1ABC FN20"
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msg="G4WJS K9AN EN50"
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i3=0
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i3=0
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n3=1
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n3=1
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call pack77(msg,i3,n3,c77) !Pack into 12 6-bit bytes
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call pack77(msg,i3,n3,c77) !Pack into 12 6-bit bytes
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@ -55,20 +59,19 @@ allocate ( rxdata(N), llr(N) )
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write(*,*) "message sent ",msgsent
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write(*,*) "message sent ",msgsent
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read(c77,'(77i1)') msgbits(1:77)
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read(c77,'(77i1)') msgbits(1:77)
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write(*,*) 'message'
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write(*,*) 'message'
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write(*,'(a71,1x,a3,1x,a3)') c77(1:71),c77(72:74),c77(75:77)
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write(*,'(a71,1x,a3,1x,a3)') c77(1:71),c77(72:74),c77(75:77)
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call encode174_91(msgbits,codeword)
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call init_random_seed()
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call init_random_seed()
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call encode174_91(msgbits,codeword)
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write(*,*) 'crc14'
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write(*,'(14i1)') codeword(78:91)
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write(*,*) 'codeword'
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write(*,*) 'codeword'
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write(*,'(22(8i1,1x))') codeword
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write(*,'(22(8i1,1x))') codeword
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write(*,*) "Eb/N0 SNR2500 ngood nundetected sigma psymerr"
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write(*,*) "Eb/N0 SNR2500 ngood nundetected sigma psymerr"
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do idb = 20,-10,-1
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do idb = 10,-4,-1
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!do idb = 0,0,-1
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db=idb/2.0-1.0
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db=idb/2.0-1.0
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sigma=1/sqrt( 2*rate*(10**(db/10.0)) )
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sigma=1/sqrt( 2*rate*(10**(db/10.0)) )
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ngood=0
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ngood=0
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@ -101,14 +104,19 @@ do idb = 20,-10,-1
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llr(1:nap)=5*(2.0*msgbits(1:nap)-1.0)
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llr(1:nap)=5*(2.0*msgbits(1:nap)-1.0)
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apmask=0
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apmask=0
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apmask(1:nap)=1
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apmask(1:nap)=1
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! max_iterations is max number of belief propagation iterations
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! max_iterations is max number of belief propagation iterations
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call bpdecode174_91(llr, apmask, max_iterations, message77, cw, nharderrors,niterations,ncheck)
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call bpdecode174_91(llr, apmask, max_iterations, message77, cw, nhardbp,niterations,ncheck)
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if( ndepth .ge. 0 .and. nharderrors .lt. 0 ) call osd174_91(llr, apmask, ndepth, message77, cw, nharderrors, dmin)
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if( ndepth .ge. 0 .and. nhardbp .lt. 0 ) then
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!call decode174_91(llr, apmask, max_iterations, message77, cw, nharderrors,niterations,ncheck,dmin,nsuper)
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dmin=0.0
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if(nbposd.eq.0) then
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call osd174_91(llr,Keff,apmask,ndepth,message91,cw,nhardosd,dmin)
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else
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maxsuper=2
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call decode174_91(llr,Keff,ndepth,apmask,maxsuper,message91,cw,nhardosd,niterations,ncheck,dmin)
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endif
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! If the decoder finds a valid codeword, nharderrors will be .ge. 0.
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! If the decoder finds a valid codeword, nharderrors will be .ge. 0.
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if( nharderrors .ge. 0 ) then
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endif
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call extractmessage77(message77,msgreceived)
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if( nhardbp .ge. 0 .or. nhardosd.ge.0 ) then
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nhw=count(cw.ne.codeword)
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nhw=count(cw.ne.codeword)
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if(nhw.eq.0) then ! this is a good decode
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if(nhw.eq.0) then ! this is a good decode
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ngood=ngood+1
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ngood=ngood+1
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@ -56,6 +56,7 @@ contains
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integer apmy_ru(28),aphis_fd(28)
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integer apmy_ru(28),aphis_fd(28)
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integer*2 iwave(NMAX) !Raw received data
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integer*2 iwave(NMAX) !Raw received data
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integer*1 message77(77),rvec(77),apmask(2*ND),cw(2*ND)
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integer*1 message77(77),rvec(77),apmask(2*ND),cw(2*ND)
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integer*1 message91(91)
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integer*1 hbits(2*NN)
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integer*1 hbits(2*NN)
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integer i4tone(103)
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integer i4tone(103)
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integer nappasses(0:5) ! # of decoding passes for QSO States 0-5
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integer nappasses(0:5) ! # of decoding passes for QSO States 0-5
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@ -412,12 +413,19 @@ contains
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call timer('bpdec174',1)
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call timer('bpdec174',1)
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if(doosd .and. nharderror.lt.0) then
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if(doosd .and. nharderror.lt.0) then
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ndeep=3
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! ndeep=3
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ndeep=2
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if(abs(nfqso-f1).le.napwid) then
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if(abs(nfqso-f1).le.napwid) then
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ndeep=4
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! ndeep=4
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ndeep=3
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endif
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endif
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call timer('osd174_91 ',0)
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call timer('osd174_91 ',0)
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call osd174_91(llr,apmask,ndeep,message77,cw,nharderror,dmin)
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Keff=91
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maxsuper=2
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! call osd174_91(llr,Keff,apmask,ndeep,message91,cw,nharderror,dmin)
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call decode174_91(llr,Keff,ndeep,apmask,maxsuper,message91,cw,nharderror, &
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niterations,ncheck,dmin)
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message77=message91(1:77)
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call timer('osd174_91 ',1)
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call timer('osd174_91 ',1)
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endif
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endif
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@ -1,13 +1,12 @@
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subroutine decode174_91(llr,apmask,maxiterations,message77,cw,nharderror,iter,ncheck,dmin,isuper)
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subroutine decode174_91(llr,Keff,ndeep,apmask,maxsuper,message91,cw,nharderror,iter,ncheck,dmin)
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!
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!
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! A hybrid bp/osd decoder for the (174,91) code.
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! A hybrid bp/osd decoder for the (174,91) code.
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!
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!
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use iso_c_binding, only: c_loc,c_size_t
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use crc
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integer, parameter:: N=174, K=91, M=N-K
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integer, parameter:: N=174, K=91, M=N-K
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integer*1 cw(N),apmask(N)
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integer*1 cw(N),apmask(N)
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integer*1 decoded(K)
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integer*1 decoded(K)
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integer*1 message77(77)
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integer*1 nxor(N),hdec(N)
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integer*1 message91(91)
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integer nrw(M),ncw
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integer nrw(M),ncw
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integer Nm(7,M)
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integer Nm(7,M)
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integer Mn(3,N) ! 3 checks per bit
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integer Mn(3,N) ! 3 checks per bit
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@ -35,7 +34,6 @@ enddo
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ncnt=0
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ncnt=0
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nclast=0
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nclast=0
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maxsuper=5
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maxiterations=1
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maxiterations=1
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zsum=0.0
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zsum=0.0
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@ -63,10 +61,12 @@ zsum=zsum+zn
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! write(*,*) 'number of unsatisfied parity checks ',ncheck
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! write(*,*) 'number of unsatisfied parity checks ',ncheck
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if( ncheck .eq. 0 ) then ! we have a codeword - if crc is good, return it
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if( ncheck .eq. 0 ) then ! we have a codeword - if crc is good, return it
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decoded=cw(1:K)
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decoded=cw(1:K)
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call chkcrc14a(decoded,nbadcrc)
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call get_crc14(decoded,91,nbadcrc)
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write(*,*) nbadcrc
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write(*,'(91i1)') decoded
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nharderror=count( (2*cw-1)*llr .lt. 0.0 )
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nharderror=count( (2*cw-1)*llr .lt. 0.0 )
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if(nbadcrc.eq.0) then
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if(nbadcrc.eq.0) then
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message77=decoded(1:77)
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message91=decoded(1:91)
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dmin=0.0
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dmin=0.0
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return
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return
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endif
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endif
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@ -118,13 +118,18 @@ dmin=0.0
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enddo
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enddo
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enddo ! bp iterations
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enddo ! bp iterations
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ndeep=1
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llr=zsum
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call osd174_91(zsum,Keff,apmask,ndeep,message91,cw,nharderror,dminosd)
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call osd174_91(llr,apmask,ndeep,message77,cw,nharderror,dmin)
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if(nharderror.gt.0) then
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if(nharderror.gt.0) then
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hdec=0
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where(llr .ge. 0) hdec=1
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nxor=ieor(hdec,cw)
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dmin=sum(nxor*abs(llr))
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return
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return
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endif
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endif
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enddo ! super iterations
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enddo ! super iterations
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nharderror=-1
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nharderror=-1
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return
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return
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end subroutine decode174_91
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end subroutine decode174_91
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@ -0,0 +1,49 @@
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subroutine encode174_91_nocrc(message,codeword)
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!
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! Add a 14-bit CRC to a 77-bit message and return a 174-bit codeword
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!
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use, intrinsic :: iso_c_binding
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use iso_c_binding, only: c_loc,c_size_t
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use crc
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integer, parameter:: N=174, K=91, M=N-K
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character*91 tmpchar
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integer*1 codeword(N)
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integer*1 gen(M,K)
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integer*1 message(K)
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integer*1 pchecks(M)
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integer*1, target :: i1MsgBytes(12)
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include "ldpc_174_91_c_generator.f90"
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logical first
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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=1,23
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read(g(i)(j:j),"(Z1)") istr
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ibmax=4
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if(j.eq.23) ibmax=3
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do jj=1, ibmax
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icol=(j-1)*4+jj
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if( btest(istr,4-jj) ) gen(i,icol)=1
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enddo
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enddo
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enddo
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||||||
|
first=.false.
|
||||||
|
endif
|
||||||
|
|
||||||
|
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 encode174_91_nocrc
|
||||||
|
|
@ -18,7 +18,7 @@ subroutine ft8b(dd0,newdat,nQSOProgress,nfqso,nftx,ndepth,nzhsym,lapon, &
|
||||||
real llra(174),llrb(174),llrc(174),llrd(174),llrz(174) !Soft symbols
|
real llra(174),llrb(174),llrc(174),llrd(174),llrz(174) !Soft symbols
|
||||||
real dd0(15*12000)
|
real dd0(15*12000)
|
||||||
real ss(9)
|
real ss(9)
|
||||||
integer*1 message77(77),apmask(174),cw(174)
|
integer*1 message77(77),message91(91),apmask(174),cw(174)
|
||||||
integer apsym(58),aph10(10)
|
integer apsym(58),aph10(10)
|
||||||
integer mcq(29),mcqru(29),mcqfd(29),mcqtest(29),mcqww(29)
|
integer mcq(29),mcqru(29),mcqfd(29),mcqtest(29),mcqww(29)
|
||||||
integer mrrr(19),m73(19),mrr73(19)
|
integer mrrr(19),m73(19),mrr73(19)
|
||||||
|
|
@ -407,12 +407,19 @@ subroutine ft8b(dd0,newdat,nQSOProgress,nfqso,nftx,ndepth,nzhsym,lapon, &
|
||||||
dmin=0.0
|
dmin=0.0
|
||||||
if(nharderrors.lt.0 .and. ncheck.le.30 .and. ndepth.ge.2) then
|
if(nharderrors.lt.0 .and. ncheck.le.30 .and. ndepth.ge.2) then
|
||||||
ndeep=ndepth
|
ndeep=ndepth
|
||||||
|
!ndeep=ndepth-1
|
||||||
if(abs(nfqso-f1).le.napwid .or. abs(nftx-f1).le.napwid .or. ncontest.eq.7) then
|
if(abs(nfqso-f1).le.napwid .or. abs(nftx-f1).le.napwid .or. ncontest.eq.7) then
|
||||||
ndeep=4
|
ndeep=4
|
||||||
|
!ndeep=3
|
||||||
endif
|
endif
|
||||||
if(nagain) ndeep=5
|
if(nagain) ndeep=5
|
||||||
|
!if(nagain) ndeep=4
|
||||||
call timer('osd174_91 ',0)
|
call timer('osd174_91 ',0)
|
||||||
call osd174_91(llrz,apmask,ndeep,message77,cw,nharderrors,dmin)
|
Keff=91
|
||||||
|
! call osd174_91(llrz,Keff,apmask,ndeep,message91,cw,nharderrors,dmin)
|
||||||
|
maxsuper=2
|
||||||
|
call decode174_91(llrz,Keff,ndeep,apmask,maxsuper,message91,cw,nharderrors,niterations,ncheck,dmin)
|
||||||
|
if(nharderrors.ge.0) message77=message91(1:77)
|
||||||
call timer('osd174_91 ',1)
|
call timer('osd174_91 ',1)
|
||||||
endif
|
endif
|
||||||
|
|
||||||
|
|
|
||||||
|
|
@ -1,78 +1,102 @@
|
||||||
subroutine osd174_91(llr,apmask,ndeep,message77,cw,nhardmin,dmin)
|
subroutine osd174_91(llr,k,apmask,ndeep,message91,cw,nhardmin,dmin)
|
||||||
!
|
!
|
||||||
! An ordered-statistics decoder for the (174,91) code.
|
! An ordered-statistics decoder for the (174,91) code.
|
||||||
|
! Message payload is 77 bits. Any or all of a 14-bit CRC can be
|
||||||
|
! used for detecting incorrect codewords. The remaining CRC bits are
|
||||||
|
! cascaded with the LDPC code for the purpose of improving the
|
||||||
|
! distance spectrum of the code.
|
||||||
!
|
!
|
||||||
integer, parameter:: N=174, K=91, M=N-K
|
! If p1 (0.le.p1.le.14) is the number of CRC14 bits that are
|
||||||
integer*1 apmask(N),apmaskr(N)
|
! to be used for bad codeword detection, then the argument k should
|
||||||
integer*1 gen(K,N)
|
! be set to 77+p1.
|
||||||
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)
|
! Valid values for k are in the range [77,91].
|
||||||
integer*1 r2pat(N-K)
|
!
|
||||||
integer indices(N),nxor(N)
|
character*14 c14
|
||||||
integer*1 cw(N),ce(N),c0(N),hdec(N)
|
integer, parameter:: N=174
|
||||||
integer*1 decoded(K)
|
integer*1 apmask(N),apmaskr(N)
|
||||||
integer*1 message77(77)
|
integer*1, allocatable, save :: gen(:,:)
|
||||||
integer indx(N)
|
integer*1, allocatable :: genmrb(:,:),g2(:,:)
|
||||||
real llr(N),rx(N),absrx(N)
|
integer*1, allocatable :: temp(:),m0(:),me(:),mi(:),misub(:),e2sub(:),e2(:),ui(:)
|
||||||
|
integer*1, allocatable :: r2pat(:)
|
||||||
|
integer indices(N),nxor(N)
|
||||||
|
integer*1 cw(N),ce(N),c0(N),hdec(N)
|
||||||
|
integer*1, allocatable :: decoded(:)
|
||||||
|
integer*1 message91(91),m96(96)
|
||||||
|
integer indx(N)
|
||||||
|
real llr(N),rx(N),absrx(N)
|
||||||
|
|
||||||
include "ldpc_174_91_c_generator.f90"
|
logical first,reset
|
||||||
|
data first/.true./
|
||||||
|
save first
|
||||||
|
|
||||||
logical first,reset
|
allocate( genmrb(k,N), g2(N,k) )
|
||||||
data first/.true./
|
allocate( temp(k), m0(k), me(k), mi(k), misub(k), e2sub(N-k), e2(N-k), ui(N-k) )
|
||||||
save first,gen
|
allocate( r2pat(N-k), decoded(k) )
|
||||||
|
|
||||||
if( first ) then ! fill the generator matrix
|
if( first ) then ! fill the generator matrix
|
||||||
|
!
|
||||||
|
! Create generator matrix for partial CRC cascaded with LDPC code.
|
||||||
|
!
|
||||||
|
! Let p2=91-k and p1+p2=14.
|
||||||
|
!
|
||||||
|
! The last p2 bits of the CRC14 are cascaded with the LDPC code.
|
||||||
|
!
|
||||||
|
! The first p1=k-77 CRC14 bits will be used for error detection.
|
||||||
|
!
|
||||||
|
allocate( gen(k,N) )
|
||||||
gen=0
|
gen=0
|
||||||
do i=1,M
|
do i=1,k
|
||||||
do j=1,23
|
message91=0
|
||||||
read(g(i)(j:j),"(Z1)") istr
|
message91(i)=1
|
||||||
ibmax=4
|
if(i.le.77) then
|
||||||
if(j.eq.23) ibmax=3
|
m96=0
|
||||||
do jj=1, ibmax
|
m96(1:91)=message91
|
||||||
irow=(j-1)*4+jj
|
call get_crc14(m96,96,ncrc14)
|
||||||
if( btest(istr,4-jj) ) gen(irow,K+i)=1
|
write(c14,'(b14.14)') ncrc14
|
||||||
|
read(c14,'(14i1)') message91(78:91)
|
||||||
|
message91(78:k)=0
|
||||||
|
endif
|
||||||
|
call encode174_91_nocrc(message91,cw)
|
||||||
|
gen(i,:)=cw
|
||||||
enddo
|
enddo
|
||||||
enddo
|
|
||||||
enddo
|
|
||||||
do irow=1,K
|
|
||||||
gen(irow,irow)=1
|
|
||||||
enddo
|
|
||||||
first=.false.
|
|
||||||
endif
|
|
||||||
|
|
||||||
rx=llr
|
first=.false.
|
||||||
apmaskr=apmask
|
endif
|
||||||
|
|
||||||
|
rx=llr
|
||||||
|
apmaskr=apmask
|
||||||
|
|
||||||
! Hard decisions on the received word.
|
! Hard decisions on the received word.
|
||||||
hdec=0
|
hdec=0
|
||||||
where(rx .ge. 0) hdec=1
|
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)
|
absrx=abs(rx)
|
||||||
call indexx(absrx,N,indx)
|
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
|
do i=1,N
|
||||||
genmrb(1:K,i)=gen(1:K,indx(N+1-i))
|
genmrb(1:k,i)=gen(1:k,indx(N+1-i))
|
||||||
indices(i)=indx(N+1-i)
|
indices(i)=indx(N+1-i)
|
||||||
enddo
|
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).
|
! received bits in positions 1:k in order of decreasing reliability (more or less).
|
||||||
do id=1,K ! diagonal element indices
|
do id=1,k ! diagonal element indices
|
||||||
do icol=id,K+20 ! The 20 is ad hoc - beware
|
do icol=id,k+20 ! The 20 is ad hoc - beware
|
||||||
iflag=0
|
iflag=0
|
||||||
if( genmrb(id,icol) .eq. 1 ) then
|
if( genmrb(id,icol) .eq. 1 ) then
|
||||||
iflag=1
|
iflag=1
|
||||||
if( icol .ne. id ) then ! reorder column
|
if( icol .ne. id ) then ! reorder column
|
||||||
temp(1:K)=genmrb(1:K,id)
|
temp(1:k)=genmrb(1:k,id)
|
||||||
genmrb(1:K,id)=genmrb(1:K,icol)
|
genmrb(1:k,id)=genmrb(1:k,icol)
|
||||||
genmrb(1:K,icol)=temp(1:K)
|
genmrb(1:k,icol)=temp(1:k)
|
||||||
itmp=indices(id)
|
itmp=indices(id)
|
||||||
indices(id)=indices(icol)
|
indices(id)=indices(icol)
|
||||||
indices(icol)=itmp
|
indices(icol)=itmp
|
||||||
endif
|
endif
|
||||||
do ii=1,K
|
do ii=1,k
|
||||||
if( ii .ne. id .and. genmrb(ii,id) .eq. 1 ) then
|
if( ii .ne. id .and. genmrb(ii,id) .eq. 1 ) then
|
||||||
genmrb(ii,1:N)=ieor(genmrb(ii,1:N),genmrb(id,1:N))
|
genmrb(ii,1:N)=ieor(genmrb(ii,1:N),genmrb(id,1:N))
|
||||||
endif
|
endif
|
||||||
|
|
@ -80,74 +104,82 @@ do id=1,K ! diagonal element indices
|
||||||
exit
|
exit
|
||||||
endif
|
endif
|
||||||
enddo
|
enddo
|
||||||
enddo
|
enddo
|
||||||
|
|
||||||
g2=transpose(genmrb)
|
g2=transpose(genmrb)
|
||||||
|
|
||||||
! The hard decisions for the K MRB bits define the order 0 message, m0.
|
! 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.
|
! 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
|
! Flip various combinations of bits in m0 and re-encode to generate a list of
|
||||||
! codewords. Return the member of the list that has the smallest Euclidean
|
! codewords. Return the member of the list that has the smallest Euclidean
|
||||||
! distance to the received word.
|
! distance to the received word.
|
||||||
|
|
||||||
hdec=hdec(indices) ! hard decisions from received symbols
|
hdec=hdec(indices) ! hard decisions from received symbols
|
||||||
m0=hdec(1:K) ! zero'th order message
|
m0=hdec(1:k) ! zero'th order message
|
||||||
absrx=absrx(indices)
|
absrx=absrx(indices)
|
||||||
rx=rx(indices)
|
rx=rx(indices)
|
||||||
apmaskr=apmaskr(indices)
|
apmaskr=apmaskr(indices)
|
||||||
|
|
||||||
call mrbencode91(m0,c0,g2,N,K)
|
call mrbencode91(m0,c0,g2,N,k)
|
||||||
nxor=ieor(c0,hdec)
|
nxor=ieor(c0,hdec)
|
||||||
nhardmin=sum(nxor)
|
nhardmin=sum(nxor)
|
||||||
dmin=sum(nxor*absrx)
|
dmin=sum(nxor*absrx)
|
||||||
|
|
||||||
cw=c0
|
cw=c0
|
||||||
ntotal=0
|
ntotal=0
|
||||||
nrejected=0
|
nrejected=0
|
||||||
npre1=0
|
npre1=0
|
||||||
npre2=0
|
npre2=0
|
||||||
|
|
||||||
if(ndeep.eq.0) goto 998 ! norder=0
|
if(ndeep.eq.0) goto 998 ! norder=0
|
||||||
if(ndeep.gt.5) ndeep=5
|
if(ndeep.gt.6) ndeep=6
|
||||||
if( ndeep.eq. 1) then
|
if( ndeep.eq. 1) then
|
||||||
nord=1
|
nord=1
|
||||||
npre1=0
|
npre1=0
|
||||||
npre2=0
|
npre2=0
|
||||||
nt=40
|
nt=40
|
||||||
ntheta=12
|
ntheta=12
|
||||||
elseif(ndeep.eq.2) then
|
elseif(ndeep.eq.2) then
|
||||||
nord=1
|
nord=1
|
||||||
npre1=1
|
npre1=1
|
||||||
npre2=0
|
npre2=0
|
||||||
nt=40
|
nt=40
|
||||||
ntheta=12
|
! ntheta=12
|
||||||
elseif(ndeep.eq.3) then
|
ntheta=10
|
||||||
|
elseif(ndeep.eq.3) then
|
||||||
nord=1
|
nord=1
|
||||||
npre1=1
|
npre1=1
|
||||||
npre2=1
|
npre2=1
|
||||||
nt=40
|
nt=40
|
||||||
ntheta=12
|
ntheta=12
|
||||||
ntau=14
|
ntau=14
|
||||||
elseif(ndeep.eq.4) then
|
elseif(ndeep.eq.4) then
|
||||||
nord=2
|
|
||||||
npre1=1
|
|
||||||
npre2=0
|
|
||||||
nt=40
|
|
||||||
ntheta=12
|
|
||||||
ntau=19
|
|
||||||
elseif(ndeep.eq.5) then
|
|
||||||
nord=2
|
nord=2
|
||||||
npre1=1
|
npre1=1
|
||||||
npre2=1
|
npre2=1
|
||||||
nt=40
|
nt=40
|
||||||
ntheta=12
|
ntheta=12
|
||||||
ntau=19
|
ntau=17
|
||||||
endif
|
elseif(ndeep.eq.5) then
|
||||||
|
nord=3
|
||||||
|
npre1=1
|
||||||
|
npre2=1
|
||||||
|
nt=40
|
||||||
|
ntheta=12
|
||||||
|
ntau=15
|
||||||
|
elseif(ndeep.eq.6) then
|
||||||
|
nord=4
|
||||||
|
npre1=1
|
||||||
|
npre2=1
|
||||||
|
nt=95
|
||||||
|
ntheta=12
|
||||||
|
ntau=15
|
||||||
|
endif
|
||||||
|
|
||||||
do iorder=1,nord
|
do iorder=1,nord
|
||||||
misub(1:K-iorder)=0
|
misub(1:k-iorder)=0
|
||||||
misub(K-iorder+1:K)=1
|
misub(k-iorder+1:k)=1
|
||||||
iflag=K-iorder+1
|
iflag=k-iorder+1
|
||||||
do while(iflag .ge.0)
|
do while(iflag .ge.0)
|
||||||
if(iorder.eq.nord .and. npre1.eq.0) then
|
if(iorder.eq.nord .and. npre1.eq.0) then
|
||||||
iend=iflag
|
iend=iflag
|
||||||
|
|
@ -158,32 +190,32 @@ do iorder=1,nord
|
||||||
do n1=iflag,iend,-1
|
do n1=iflag,iend,-1
|
||||||
mi=misub
|
mi=misub
|
||||||
mi(n1)=1
|
mi(n1)=1
|
||||||
if(any(iand(apmaskr(1:K),mi).eq.1)) cycle
|
if(any(iand(apmaskr(1:k),mi).eq.1)) cycle
|
||||||
ntotal=ntotal+1
|
ntotal=ntotal+1
|
||||||
me=ieor(m0,mi)
|
me=ieor(m0,mi)
|
||||||
if(n1.eq.iflag) then
|
if(n1.eq.iflag) then
|
||||||
call mrbencode91(me,ce,g2,N,K)
|
call mrbencode91(me,ce,g2,N,k)
|
||||||
e2sub=ieor(ce(K+1:N),hdec(K+1:N))
|
e2sub=ieor(ce(k+1:N),hdec(k+1:N))
|
||||||
e2=e2sub
|
e2=e2sub
|
||||||
nd1Kpt=sum(e2sub(1:nt))+1
|
nd1kpt=sum(e2sub(1:nt))+1
|
||||||
d1=sum(ieor(me(1:K),hdec(1:K))*absrx(1:K))
|
d1=sum(ieor(me(1:k),hdec(1:k))*absrx(1:k))
|
||||||
else
|
else
|
||||||
e2=ieor(e2sub,g2(K+1:N,n1))
|
e2=ieor(e2sub,g2(k+1:N,n1))
|
||||||
nd1Kpt=sum(e2(1:nt))+2
|
nd1kpt=sum(e2(1:nt))+2
|
||||||
endif
|
endif
|
||||||
if(nd1Kpt .le. ntheta) then
|
if(nd1kpt .le. ntheta) then
|
||||||
call mrbencode91(me,ce,g2,N,K)
|
call mrbencode91(me,ce,g2,N,k)
|
||||||
nxor=ieor(ce,hdec)
|
nxor=ieor(ce,hdec)
|
||||||
if(n1.eq.iflag) then
|
if(n1.eq.iflag) then
|
||||||
dd=d1+sum(e2sub*absrx(K+1:N))
|
dd=d1+sum(e2sub*absrx(k+1:N))
|
||||||
else
|
else
|
||||||
dd=d1+ieor(ce(n1),hdec(n1))*absrx(n1)+sum(e2*absrx(K+1:N))
|
dd=d1+ieor(ce(n1),hdec(n1))*absrx(n1)+sum(e2*absrx(k+1:N))
|
||||||
endif
|
endif
|
||||||
if( dd .lt. dmin ) then
|
if( dd .lt. dmin ) then
|
||||||
dmin=dd
|
dmin=dd
|
||||||
cw=ce
|
cw=ce
|
||||||
nhardmin=sum(nxor)
|
nhardmin=sum(nxor)
|
||||||
nd1Kptbest=nd1Kpt
|
nd1kptbest=nd1kpt
|
||||||
endif
|
endif
|
||||||
else
|
else
|
||||||
nrejected=nrejected+1
|
nrejected=nrejected+1
|
||||||
|
|
@ -193,15 +225,15 @@ do iorder=1,nord
|
||||||
! when the last pattern with weight iorder has been generated.
|
! when the last pattern with weight iorder has been generated.
|
||||||
call nextpat91(misub,k,iorder,iflag)
|
call nextpat91(misub,k,iorder,iflag)
|
||||||
enddo
|
enddo
|
||||||
enddo
|
enddo
|
||||||
|
|
||||||
if(npre2.eq.1) then
|
if(npre2.eq.1) then
|
||||||
reset=.true.
|
reset=.true.
|
||||||
ntotal=0
|
ntotal=0
|
||||||
do i1=K,1,-1
|
do i1=k,1,-1
|
||||||
do i2=i1-1,1,-1
|
do i2=i1-1,1,-1
|
||||||
ntotal=ntotal+1
|
ntotal=ntotal+1
|
||||||
mi(1:ntau)=ieor(g2(K+1:K+ntau,i1),g2(K+1:K+ntau,i2))
|
mi(1:ntau)=ieor(g2(k+1:k+ntau,i1),g2(k+1:k+ntau,i2))
|
||||||
call boxit91(reset,mi(1:ntau),ntau,ntotal,i1,i2)
|
call boxit91(reset,mi(1:ntau),ntau,ntotal,i1,i2)
|
||||||
enddo
|
enddo
|
||||||
enddo
|
enddo
|
||||||
|
|
@ -210,13 +242,13 @@ if(npre2.eq.1) then
|
||||||
ntotal2=0
|
ntotal2=0
|
||||||
reset=.true.
|
reset=.true.
|
||||||
! Now run through again and do the second pre-processing rule
|
! Now run through again and do the second pre-processing rule
|
||||||
misub(1:K-nord)=0
|
misub(1:k-nord)=0
|
||||||
misub(K-nord+1:K)=1
|
misub(k-nord+1:k)=1
|
||||||
iflag=K-nord+1
|
iflag=k-nord+1
|
||||||
do while(iflag .ge.0)
|
do while(iflag .ge.0)
|
||||||
me=ieor(m0,misub)
|
me=ieor(m0,misub)
|
||||||
call mrbencode91(me,ce,g2,N,K)
|
call mrbencode91(me,ce,g2,N,k)
|
||||||
e2sub=ieor(ce(K+1:N),hdec(K+1:N))
|
e2sub=ieor(ce(k+1:N),hdec(k+1:N))
|
||||||
do i2=0,ntau
|
do i2=0,ntau
|
||||||
ntotal2=ntotal2+1
|
ntotal2=ntotal2+1
|
||||||
ui=0
|
ui=0
|
||||||
|
|
@ -229,9 +261,9 @@ if(npre2.eq.1) then
|
||||||
mi=misub
|
mi=misub
|
||||||
mi(in1)=1
|
mi(in1)=1
|
||||||
mi(in2)=1
|
mi(in2)=1
|
||||||
if(sum(mi).lt.nord+npre1+npre2.or.any(iand(apmaskr(1:K),mi).eq.1)) cycle
|
if(sum(mi).lt.nord+npre1+npre2.or.any(iand(apmaskr(1:k),mi).eq.1)) cycle
|
||||||
me=ieor(m0,mi)
|
me=ieor(m0,mi)
|
||||||
call mrbencode91(me,ce,g2,N,K)
|
call mrbencode91(me,ce,g2,N,k)
|
||||||
nxor=ieor(ce,hdec)
|
nxor=ieor(ce,hdec)
|
||||||
dd=sum(nxor*absrx)
|
dd=sum(nxor*absrx)
|
||||||
if( dd .lt. dmin ) then
|
if( dd .lt. dmin ) then
|
||||||
|
|
@ -242,24 +274,26 @@ if(npre2.eq.1) then
|
||||||
goto 778
|
goto 778
|
||||||
endif
|
endif
|
||||||
enddo
|
enddo
|
||||||
call nextpat91(misub,K,nord,iflag)
|
call nextpat91(misub,k,nord,iflag)
|
||||||
enddo
|
enddo
|
||||||
endif
|
endif
|
||||||
|
|
||||||
998 continue
|
998 continue
|
||||||
! Re-order the codeword to [message bits][parity bits] format.
|
! Re-order the codeword to [message bits][parity bits] format.
|
||||||
cw(indices)=cw
|
cw(indices)=cw
|
||||||
hdec(indices)=hdec
|
hdec(indices)=hdec
|
||||||
decoded=cw(1:K)
|
message91=cw(1:91)
|
||||||
call chkcrc14a(decoded,nbadcrc)
|
m96=0
|
||||||
message77=decoded(1:77)
|
m96(1:77)=cw(1:77)
|
||||||
if(nbadcrc.eq.1) nhardmin=-nhardmin
|
m96(83:96)=cw(78:91)
|
||||||
|
call get_crc14(m96,96,nbadcrc)
|
||||||
|
if(nbadcrc.ne.0) nhardmin=-nhardmin
|
||||||
|
|
||||||
return
|
return
|
||||||
end subroutine osd174_91
|
end subroutine osd174_91
|
||||||
|
|
||||||
subroutine mrbencode91(me,codeword,g2,N,K)
|
subroutine mrbencode91(me,codeword,g2,N,K)
|
||||||
integer*1 me(K),codeword(N),g2(N,K)
|
integer*1 me(K),codeword(N),g2(N,K)
|
||||||
! fast encoding for low-weight test patterns
|
! fast encoding for low-weight test patterns
|
||||||
codeword=0
|
codeword=0
|
||||||
do i=1,K
|
do i=1,K
|
||||||
|
|
@ -267,7 +301,7 @@ integer*1 me(K),codeword(N),g2(N,K)
|
||||||
codeword=ieor(codeword,g2(1:N,i))
|
codeword=ieor(codeword,g2(1:N,i))
|
||||||
endif
|
endif
|
||||||
enddo
|
enddo
|
||||||
return
|
return
|
||||||
end subroutine mrbencode91
|
end subroutine mrbencode91
|
||||||
|
|
||||||
subroutine nextpat91(mi,k,iorder,iflag)
|
subroutine nextpat91(mi,k,iorder,iflag)
|
||||||
|
|
|
||||||
Loading…
Reference in New Issue