mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-11-05 00:41:19 -05:00
206 lines
6.1 KiB
Fortran
206 lines
6.1 KiB
Fortran
program ldpcsim204
|
|
|
|
! End-to-end test of the (300,60)/crc10 encoder and decoders.
|
|
|
|
use crc
|
|
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 ncrc14,nrcrc14
|
|
integer colorder(204)
|
|
integer nerrtot(204),nerrdec(204),nmpcbad(68)
|
|
logical checksumok,fsk,bpsk
|
|
real*8, allocatable :: rxdata(:)
|
|
real, allocatable :: llr(:)
|
|
real dllr(204),llrd(204)
|
|
|
|
data colorder/ &
|
|
0, 1, 2, 3, 4, 5, 47, 6, 7, 8, 9, 10, 11, 12, 58, 55, 13, &
|
|
14, 15, 46, 17, 18, 60, 19, 20, 21, 22, 23, 24, 25, 57, 26, 27, 49, &
|
|
28, 52, 65, 16, 50, 73, 59, 68, 63, 29, 30, 31, 32, 51, 62, 56, 66, &
|
|
45, 33, 34, 53, 67, 35, 36, 37, 61, 69, 54, 38, 71, 82, 39, 77, 80, &
|
|
83, 78, 84, 48, 41, 85, 40, 64, 75, 96, 74, 72, 76, 86, 87, 89, 90, &
|
|
79, 70, 92, 99, 93,101, 95,100, 97, 94, 42, 98,103,105,102, 43,104, &
|
|
88, 44,106, 81,107,110,108,111,112,109,113,114,117,118,116,121,115, &
|
|
119,122,120,125,129,124,127,126,128, 91,123,133,131,130,134,135,137, &
|
|
136,132,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152, &
|
|
153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169, &
|
|
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
|
|
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.4) then
|
|
print*,'Usage: ldpcsim niter ndeep #trials s '
|
|
print*,'eg: ldpcsim 100 4 1000 0.84'
|
|
print*,'If s is negative, then value is ignored and sigma is calculated from SNR.'
|
|
return
|
|
endif
|
|
call getarg(1,arg)
|
|
read(arg,*) max_iterations
|
|
call getarg(2,arg)
|
|
read(arg,*) ndeep
|
|
call getarg(3,arg)
|
|
read(arg,*) ntrials
|
|
call getarg(4,arg)
|
|
read(arg,*) s
|
|
|
|
fsk=.false.
|
|
bpsk=.true.
|
|
|
|
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) )
|
|
|
|
read(cmsg,'(68i1)') msgbits
|
|
call get_crc14(msgbits,ncrcsf)
|
|
write(c14,'(b14.14)') ncrcsf
|
|
read(c14,'(14i1)') msgbits(55:68)
|
|
|
|
write(*,*) 'message'
|
|
write(*,'(9(8i1,1x))') msgbits
|
|
|
|
call encode204(msgbits,codeword)
|
|
call init_random_seed()
|
|
call sgran()
|
|
|
|
write(*,*) 'codeword'
|
|
write(*,'(204i1)') codeword
|
|
|
|
write(*,*) "Eb/N0 SNR2500 ngood nundetected nbadcrc sigma"
|
|
do idb = 10,-10,-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*(10**(db/10.0)) ) ! db represents Es/No
|
|
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
|
|
if(nerr.ge.1) nerrtot(nerr)=nerrtot(nerr)+1
|
|
nberr=nberr+nerr
|
|
|
|
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)
|
|
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
|
|
|
|
! If the decoder finds a valid codeword, niterations will be .ge. 0.
|
|
if( niterations .ge. 0 ) then
|
|
call get_crc14(decoded,ncheck)
|
|
ncrcflag=0
|
|
if(ncheck.eq.0) ncrcflag=1
|
|
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
|
|
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
|
|
if(nerr.ge.1) nerrdec(nerr)=nerrdec(nerr)+1
|
|
else if( ncrcflag .eq. 1 .and. nueflag .eq. 1 ) then
|
|
nue=nue+1;
|
|
endif
|
|
endif
|
|
enddo
|
|
snr2500=db+10*log10(200.0/116.0/2500.0)
|
|
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=1,120
|
|
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=1,68
|
|
write(25,'(i4,2x,i10)') i,nmpcbad(i)
|
|
enddo
|
|
close(25)
|
|
|
|
|
|
|
|
end program ldpcsim204
|