Some repairs and tweaks to development-related programs in fsk4hf directory.

lib/fsk4hf/get_crc14.f90

@@ -0,0 +1,22 @@
+subroutine get_crc14(mc,ncrc)
+  
+  character c14*14
+
+  integer*1 mc(68),r(15),p(15)
+  integer ncrc
+! polynomial for 14-bit CRC 0x6757
+  data p/1,1,0,0,1,1,1,0,1,0,1,0,1,1,1/
+  
+! divide by polynomial
+  r=mc(1:15)
+  do i=0,53
+    r(15)=mc(i+15)
+    r=mod(r+r(1)*p,2)
+    r=cshift(r,1)
+  enddo
+
+  write(c14,'(14b1)') r(1:14)
+  read(c14,'(b14.14)') ncrc
+!  mc(55:68)=r(1:14)
+
+end subroutine get_crc14

lib/fsk4hf/ldpcsim204.f90

@@ -8,13 +8,15 @@ use packjt
 parameter(NRECENT=10)
 character*12 recent_calls(NRECENT)
 character*8 arg
+character*68 cmsg
+character*14 c14
 integer*1, allocatable ::  codeword(:), decoded(:), message(:)
 integer*1, target:: i1Msg8BitBytes(9)
 integer*1, target:: i1Dec8BitBytes(9)
 integer*1 msgbits(68)
 integer*1 apmask(204)
 integer*1 cw(204)
-integer*2 checksum
+integer*2 ncrc14,nrcrc14
 integer colorder(204)
 integer nerrtot(204),nerrdec(204),nmpcbad(68)
 logical checksumok,fsk,bpsk
@@ -36,6 +38,8 @@ data colorder/                                                              &
        170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186, &
        187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203/
 
+data cmsg/'11111111000000001111111100000000111111110000000011000000000000000000'/
+
 do i=1,NRECENT
   recent_calls(i)='            '
 enddo
@@ -66,41 +70,17 @@ N=204
 K=68
 rate=real(K)/real(N)
 
+
 write(*,*) "rate: ",rate
 write(*,*) "niter= ",max_iterations," s= ",s
 
 allocate ( codeword(N), decoded(K), message(K) )
 allocate ( rxdata(N), llr(N) )
 
-! The message should be packed into the first 7 bytes
+  read(cmsg,'(68i1)') msgbits
-  i1Msg8BitBytes(1:6)=85
+  call get_crc14(msgbits,ncrcsf)
-  i1Msg8BitBytes(7)=64
+  write(c14,'(b14.14)') ncrcsf
-! The CRC will be put into the last 2 bytes
+  read(c14,'(14i1)') msgbits(55:68)
-  i1Msg8BitBytes(8:9)=0
-  checksum = crc10 (c_loc (i1Msg8BitBytes), 9)
-! For reference, the next 3 lines show how to check the CRC
-  i1Msg8BitBytes(8)=checksum/256
-  i1Msg8BitBytes(9)=iand (checksum,255)
-  checksumok = crc10_check(c_loc (i1Msg8BitBytes), 9)
-  if( checksumok ) write(*,*) 'Good checksum'
-write(*,*) i1Msg8BitBytes(1:9)
-
-  mbit=0
-  do i=1, 7 
-    i1=i1Msg8BitBytes(i)
-    do ibit=1,8
-      mbit=mbit+1
-      msgbits(mbit)=iand(1,ishft(i1,ibit-8))
-    enddo
-  enddo
-  i1=i1Msg8BitBytes(8) ! First 2 bits of crc10 are LSB of this byte
-  do ibit=1,2
-    msgbits(50+ibit)=iand(1,ishft(i1,ibit-2))
-  enddo
-  i1=i1Msg8BitBytes(9) ! Now shift in last 8 bits of the CRC
-  do ibit=1,8
-    msgbits(52+ibit)=iand(1,ishft(i1,ibit-8))
-  enddo
 
   write(*,*) 'message'
   write(*,'(9(8i1,1x))') msgbits
@@ -112,12 +92,12 @@ write(*,*) i1Msg8BitBytes(1:9)
   write(*,*) 'codeword' 
   write(*,'(204i1)') codeword
 
-write(*,*) "Es/N0  SNR2500   ngood  nundetected nbadcrc   sigma"
+write(*,*) "Eb/N0  SNR2500   ngood  nundetected nbadcrc   sigma"
-do idb = 20,-18,-1
+do idb = 10,-10,-1
-!do idb = -16, -16, -1 
+!do idb = 2, 2, -1 
   db=idb/2.0-1.0
-!  sigma=1/sqrt( 2*rate*(10**(db/10.0)) )  ! to make db represent Eb/No
+  sigma=1/sqrt( 2*rate*(10**(db/10.0)) )  ! to make db represent Eb/No
-  sigma=1/sqrt( 2*(10**(db/10.0)) )        ! db represents Es/No
+!  sigma=1/sqrt( 2*(10**(db/10.0)) )        ! db represents Es/No
   ngood=0
   nue=0
   nbadcrc=0
@@ -147,7 +127,6 @@ do idb = 20,-18,-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)
@@ -166,58 +145,35 @@ do idb = 20,-18,-1
     apmask=0
 ! max_iterations is max number of belief propagation iterations
     call bpdecode204(llr,apmask,max_iterations,decoded,cw,nharderror,niterations)
+    if(nharderror.lt.0) niterations=-1
     if( (nharderror .lt. 0) .and. (ndeep .ge. 0) ) then
        call osd204(llr, apmask, ndeep, decoded, cw, nhardmin, dmin)
        niterations=nhardmin
     endif
+
     n2err=0
     do i=1,N
       if( cw(i)*(2*codeword(i)-1.0) .lt. 0 ) n2err=n2err+1
     enddo
-!write(*,*) nerr,niterations,n2err
-    damp=0.75
-    ndither=0
-    if( niterations .lt. 0 ) then
-      do i=1, ndither
-        do in=1,N
-          dllr(in)=damp*gran()  
-        enddo
-        llrd=llr+dllr      
-        call bpdecode300(llrd, apmask, max_iterations, decoded, cw, nharderror, niterations)
-        if( niterations .ge. 0 ) exit 
-      enddo
-    endif  
 
 ! If the decoder finds a valid codeword, niterations will be .ge. 0.
     if( niterations .ge. 0 ) then
-! Check the CRC
+      call get_crc14(decoded,ncheck)
-      do ibyte=1,6
-        itmp=0
-        do ibit=1,8
-          itmp=ishft(itmp,1)+iand(1,decoded((ibyte-1)*8+ibit))
-        enddo
-        i1Dec8BitBytes(ibyte)=itmp
-      enddo
-      i1Dec8BitBytes(7)=decoded(49)*128+decoded(50)*64
-! Need to pack the received crc into bytes 8 and 9 for crc10_check
-      i1Dec8BitBytes(8)=decoded(51)*2+decoded(52)
-      i1Dec8BitBytes(9)=decoded(53)*128+decoded(54)*64+decoded(55)*32+decoded(56)*16
-      i1Dec8BitBytes(9)=i1Dec8BitBytes(9)+decoded(57)*8+decoded(58)*4+decoded(59)*2+decoded(60)*1
       ncrcflag=0
-      if( crc10_check( c_loc( i1Dec8BitBytes ), 9 ) ) ncrcflag=1
+      if(ncheck.eq.0) ncrcflag=1 
-
       if( ncrcflag .ne. 1 ) then
         nbadcrc=nbadcrc+1
       endif
-      nueflag=0
 
+      nueflag=0
       nerrmpc=0
       do i=1,K   ! find number of errors in message+crc part of codeword
         if( msgbits(i) .ne. decoded(i) ) then
-          nueflag=1
+          if(ncrcflag.eq.1) nueflag=1
           nerrmpc=nerrmpc+1 
         endif
       enddo
+
       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

lib/fsk4hf/ldpcsim300.f90

@@ -117,12 +117,12 @@ write(*,*) i1Msg8BitBytes(1:9)
   write(*,*) 'codeword' 
   write(*,'(38(8i1,1x))') codeword
 
-write(*,*) "Es/N0  SNR2500   ngood  nundetected nbadcrc   sigma"
+write(*,*) "Eb/N0  SNR2500   ngood  nundetected nbadcrc   sigma"
 do idb = 20,-16,-1
 !do idb = -16, -16, -1 
   db=idb/2.0-1.0
-!  sigma=1/sqrt( 2*rate*(10**(db/10.0)) )  ! to make db represent Eb/No
+  sigma=1/sqrt( 2*rate*(10**(db/10.0)) )  ! to make db represent Eb/No
-  sigma=1/sqrt( 2*(10**(db/10.0)) )        ! db represents Es/No
+!  sigma=1/sqrt( 2*(10**(db/10.0)) )        ! db represents Es/No
   ngood=0
   nue=0
   nbadcrc=0

lib/fsk4hf/osd204.f90

@@ -102,7 +102,7 @@ ntotal=0
 nrejected=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
    nord=1
    npre1=0
@@ -136,6 +136,13 @@ elseif(ndeep.eq.5) then
    nt=40
    ntheta=12
    ntau=19
+elseif(ndeep.eq.6) then
+   nord=3
+   npre1=1
+   npre2=1
+   nt=60
+   ntheta=22
+   ntau=16
 endif
 
 do iorder=1,nord