mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-12-24 11:40:31 -05:00
dd1362b69a
Generic message packing and unpacking routines now understand antipode grid contest messages. These messages are now recognized as standard messages in message response processing and dealt with appropriately when contest mode is selected and applicable (currently FT8 and MSK144 only). git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@8062 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
234 lines
6.5 KiB
Fortran
234 lines
6.5 KiB
Fortran
program ldpcsim168
|
|
! End to end test of the (168,84)/crc12 encoder and decoder.
|
|
use crc
|
|
use packjt
|
|
|
|
parameter(NRECENT=10)
|
|
character*12 recent_calls(NRECENT)
|
|
character*22 msg,msgsent,msgreceived
|
|
character*8 arg
|
|
integer*1, allocatable :: codeword(:), decoded(:), message(:)
|
|
integer*1, target:: i1Msg8BitBytes(11)
|
|
integer*1 msgbits(84)
|
|
integer*1 apmask(168), cw(168)
|
|
integer*2 checksum
|
|
integer*4 i4Msg6BitWords(13)
|
|
integer colorder(168)
|
|
integer nerrtot(168),nerrdec(168),nmpcbad(84)
|
|
logical checksumok,fsk,bpsk
|
|
real*8, allocatable :: rxdata(:)
|
|
real, allocatable :: llr(:)
|
|
|
|
data colorder/0,1,2,3,28,4,5,6,7,8,9,10,11,34,12,32,13,14,15,16,17, &
|
|
18,36,29,42,31,20,21,41,40,30,38,22,19,47,37,46,35,44,33,49,24, &
|
|
43,51,25,26,27,50,52,57,69,54,55,45,59,58,56,61,60,53,48,23,62, &
|
|
63,64,67,66,65,68,39,70,71,72,74,73,75,76,77,80,81,78,82,79,83, &
|
|
84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104, &
|
|
105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125, &
|
|
126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146, &
|
|
147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167/
|
|
|
|
do i=1,NRECENT
|
|
recent_calls(i)=' '
|
|
enddo
|
|
nerrtot=0
|
|
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 10 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
|
|
call getarg(3,arg)
|
|
read(arg,*) s
|
|
|
|
fsk=.false.
|
|
bpsk=.true.
|
|
|
|
! don't count crc bits as data bits
|
|
N=168
|
|
K=84
|
|
! scale Eb/No for a (168,72) code
|
|
rate=real(72)/real(N)
|
|
|
|
write(*,*) "rate: ",rate
|
|
write(*,*) "niter= ",max_iterations," s= ",s
|
|
|
|
allocate ( codeword(N), decoded(K), message(K) )
|
|
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
|
|
write(*,*) "message sent ",msgsent
|
|
|
|
i4=0
|
|
ik=0
|
|
im=0
|
|
do i=1,12
|
|
nn=i4Msg6BitWords(i)
|
|
do j=1, 6
|
|
ik=ik+1
|
|
i4=i4+i4+iand(1,ishft(nn,j-6))
|
|
i4=iand(i4,255)
|
|
if(ik.eq.8) then
|
|
im=im+1
|
|
! if(i4.gt.127) i4=i4-256
|
|
i1Msg8BitBytes(im)=i4
|
|
ik=0
|
|
endif
|
|
enddo
|
|
enddo
|
|
|
|
i1Msg8BitBytes(10:11)=0
|
|
checksum = crc12 (c_loc (i1Msg8BitBytes), 11)
|
|
! For reference, the next 3 lines show how to check the CRC
|
|
i1Msg8BitBytes(10)=checksum/256
|
|
i1Msg8BitBytes(11)=iand (checksum,255)
|
|
checksumok = crc12_check(c_loc (i1Msg8BitBytes), 11)
|
|
if( checksumok ) write(*,*) 'Good checksum'
|
|
|
|
mbit=0
|
|
do i=1, 9
|
|
i1=i1Msg8BitBytes(i)
|
|
do ibit=1,8
|
|
mbit=mbit+1
|
|
msgbits(mbit)=iand(1,ishft(i1,ibit-8))
|
|
enddo
|
|
enddo
|
|
i1=i1Msg8BitBytes(10) ! First 4 bits of crc12 are LSB of this byte
|
|
do ibit=1,4
|
|
msgbits(72+ibit)=iand(1,ishft(i1,ibit-4))
|
|
enddo
|
|
i1=i1Msg8BitBytes(11) ! Now shift in last 8 bits of the CRC
|
|
do ibit=1,8
|
|
msgbits(76+ibit)=iand(1,ishft(i1,ibit-8))
|
|
enddo
|
|
|
|
write(*,*) 'message'
|
|
write(*,'(11(8i1,1x))') msgbits
|
|
|
|
call encode168(msgbits,codeword)
|
|
call init_random_seed()
|
|
call sgran()
|
|
|
|
write(*,*) 'codeword'
|
|
write(*,'(21(8i1,1x))') codeword
|
|
|
|
write(*,*) "Es/N0 SNR2500 ngood nundetected nbadcrc sigma"
|
|
do idb = 6,-6,-1
|
|
db=idb/2.0-1.0
|
|
sigma=1/sqrt( 2*(10**(db/10.0)) )
|
|
ngood=0
|
|
nue=0
|
|
nbadcrc=0
|
|
nberr=0
|
|
do itrial=1, ntrials
|
|
! Create a realization of a noisy received word
|
|
do i=1,N
|
|
if( bpsk ) then
|
|
rxdata(i) = 2.0*codeword(i)-1.0 + sigma*gran()
|
|
elseif( fsk ) then
|
|
if( codeword(i) .eq. 1 ) then
|
|
r1=(1.0 + sigma*gran())**2 + (sigma*gran())**2
|
|
r2=(sigma*gran())**2 + (sigma*gran())**2
|
|
elseif( codeword(i) .eq. 0 ) then
|
|
r2=(1.0 + sigma*gran())**2 + (sigma*gran())**2
|
|
r1=(sigma*gran())**2 + (sigma*gran())**2
|
|
endif
|
|
rxdata(i)=0.35*(sqrt(r1)-sqrt(r2))
|
|
! rxdata(i)=0.35*(exp(r1)-exp(r2))
|
|
! rxdata(i)=0.12*(log(r1)-log(r2))
|
|
endif
|
|
enddo
|
|
nerr=0
|
|
do i=1,N
|
|
if( rxdata(i)*(2*codeword(i)-1.0) .lt. 0 ) nerr=nerr+1
|
|
enddo
|
|
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
|
|
! 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
|
|
! magnitude in UER
|
|
if( s .lt. 0 ) then
|
|
ss=sigma
|
|
else
|
|
ss=s
|
|
endif
|
|
|
|
llr=2.0*rxdata/(ss*ss)
|
|
nap=0 ! number of AP bits
|
|
llr(colorder(168-84+1:168-84+nap)+1)=5*(2.0*msgbits(1:nap)-1.0)
|
|
apmask=0
|
|
apmask(colorder(168-84+1:168-84+nap)+1)=1
|
|
|
|
! max_iterations is max number of belief propagation iterations
|
|
call bpdecode168(llr, apmask, max_iterations, decoded, niterations)
|
|
! if( niterations .eq. -1 ) then
|
|
! norder=3
|
|
! call osd168(llr, norder, decoded, niterations, cw)
|
|
! endif
|
|
! If the decoder finds a valid codeword, niterations will be .ge. 0.
|
|
if( niterations .ge. 0 ) then
|
|
call extractmessage168(decoded,msgreceived,ncrcflag,recent_calls,nrecent)
|
|
if( ncrcflag .ne. 1 ) then
|
|
nbadcrc=nbadcrc+1
|
|
endif
|
|
|
|
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
|
|
nerrmpc=nerrmpc+1
|
|
endif
|
|
enddo
|
|
|
|
write(37,*) niterations, ncrcflag, nueflag
|
|
nmpcbad(nerrmpc)=nmpcbad(nerrmpc)+1
|
|
if( ncrcflag .eq. 1 ) then
|
|
if( nueflag .eq. 0 ) then
|
|
ngood=ngood+1
|
|
nerrdec(nerr)=nerrdec(nerr)+1
|
|
else if( nueflag .eq. 1 ) then
|
|
nue=nue+1;
|
|
endif
|
|
endif
|
|
endif
|
|
enddo
|
|
snr2500=db+10*log10(10.417/2500.0)
|
|
pberr=real(nberr)/(real(ntrials*N))
|
|
write(*,"(f4.1,4x,f5.1,1x,i8,1x,i8,1x,i8,8x,f5.2,8x,e10.3)") db,snr2500,ngood,nue,nbadcrc,ss,pberr
|
|
|
|
enddo
|
|
|
|
open(unit=23,file='nerrhisto.dat',status='unknown')
|
|
do i=1,168
|
|
write(23,'(i4,2x,i10,i10,f10.2)') i,nerrdec(i),nerrtot(i),real(nerrdec(i))/real(nerrtot(i)+1e-10)
|
|
enddo
|
|
close(23)
|
|
open(unit=25,file='nmpcbad.dat',status='unknown')
|
|
do i=1,84
|
|
write(25,'(i4,2x,i10)') i,nmpcbad(i)
|
|
enddo
|
|
close(25)
|
|
|
|
|
|
|
|
end program ldpcsim168
|