Implement AP decoding for JT65 (VHF/UHF/Microwave only).

git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@8277 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
This commit is contained in:
Steven Franke 2017-12-02 16:04:51 +00:00
parent 6eeece9a4b
commit e90cc846bb
6 changed files with 333 additions and 29 deletions

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@ -604,7 +604,7 @@ set (qra_CSRCS
set (wsjt_CSRCS set (wsjt_CSRCS
${ka9q_CSRCS} ${ka9q_CSRCS}
lib/ftrsd/ftrsd2.c lib/ftrsd/ftrsdap.c
lib/sgran.c lib/sgran.c
lib/golay24_table.c lib/golay24_table.c
lib/gran.c lib/gran.c

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@ -21,7 +21,8 @@ subroutine decode65b(s2,nflip,nadd,mode65,ntrials,naggressive,ndepth, &
enddo enddo
call extract(s3,nadd,mode65,ntrials,naggressive,ndepth,nflip,mycall, & call extract(s3,nadd,mode65,ntrials,naggressive,ndepth,nflip,mycall, &
hiscall,hisgrid,nexp_decode,ncount,nhist,decoded,ltext,nft,qual) hiscall,hisgrid,nQSOProgress,ljt65apon,nexp_decode,ncount, &
nhist,decoded,ltext,nft,qual)
! Suppress "birdie messages" and other garbage decodes: ! Suppress "birdie messages" and other garbage decodes:
if(decoded(1:7).eq.'000AAA ') ncount=-1 if(decoded(1:7).eq.'000AAA ') ncount=-1

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@ -366,7 +366,7 @@ contains
endif endif
nap=ishft(ft,-2) nap=ishft(ft,-2)
if(nap.ne.0) then if(nap.ne.0) then
write(cflags(1:3),'(a1,i2.2)') 'a',nap write(cflags(1:3),'(a1,i1)') 'a',nap
endif endif
endif endif
csync='# ' csync='# '

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@ -1,6 +1,7 @@
subroutine extract(s3,nadd,mode65,ntrials,naggressive,ndepth,nflip, & subroutine extract(s3,nadd,mode65,ntrials,naggressive,ndepth,nflip, &
mycall_12,hiscall_12,hisgrid,nexp_decode,ncount,nhist,decoded, & mycall_12,hiscall_12,hisgrid,nQSOProgress,ljt65apon, &
ltext,nft,qual) nexp_decode,ncount, &
nhist,decoded,ltext,nft,qual)
! Input: ! Input:
! s3 64-point spectra for each of 63 data symbols ! s3 64-point spectra for each of 63 data symbols
@ -20,19 +21,73 @@ subroutine extract(s3,nadd,mode65,ntrials,naggressive,ndepth,nflip, &
use timer_module, only: timer use timer_module, only: timer
real s3(64,63) real s3(64,63)
character decoded*22 character decoded*22, apmessage*22
character*12 mycall_12,hiscall_12 character*12 mycall_12,hiscall_12
character*6 mycall,hiscall,hisgrid character*6 mycall,hiscall,hisgrid
character*6 mycall0,hiscall0,hisgrid0
integer apsymbols(5,12),ap(12)
integer nappasses(0:5) ! the number of decoding passes to use for each QSO state
integer naptypes(0:5,4) ! (nQSOProgress, decoding pass) maximum of 4 passes for now
integer dat4(12) integer dat4(12)
integer mrsym(63),mr2sym(63),mrprob(63),mr2prob(63) integer mrsym(63),mr2sym(63),mrprob(63),mr2prob(63)
integer correct(63),tmp(63) integer correct(63),tmp(63)
logical ltext logical first,ltext,ljt65apon
common/chansyms65/correct common/chansyms65/correct
data first/.true./
save save
if(mode65.eq.-99) stop !Silence compiler warning if(mode65.eq.-99) stop !Silence compiler warning
if(first) then
! aptype
!------------------------
! 1 CQ ??? ???
! 2 MyCall ??? ???
! 3 MyCall DxCall ???
! 4 MyCall DxCall RRR
! 5 MyCall DxCall 73
apsymbols=-1
nappasses=(/2,2,2,3,3,3/)
naptypes(0,1:4)=(/1,2,0,0/)
naptypes(1,1:4)=(/2,3,0,0/)
naptypes(2,1:4)=(/2,3,0,0/)
naptypes(3,1:4)=(/3,4,5,0/)
naptypes(4,1:4)=(/3,4,5,0/)
naptypes(5,1:4)=(/3,1,2,0/)
first=.false.
endif
mycall=mycall_12(1:6) mycall=mycall_12(1:6)
hiscall=hiscall_12(1:6) hiscall=hiscall_12(1:6)
! Fill apsymbols array
if(ljt65apon .and. (mycall.ne.mycall0 .or. hiscall.ne.hiscall0)) then
!write(*,*) 'initializing apsymbols '
apsymbols=-1
mycall0=mycall
hiscall0=hiscall
ap=-1
apsymbols(1,1:4)=(/62,32,32,49/) ! CQ
if(len_trim(mycall).gt.0) then
apmessage=mycall//" "//mycall//" RRR"
call packmsg(apmessage,ap,itype,.false.)
if(itype.ne.1) ap=-1
apsymbols(2,1:4)=ap(1:4)
!write(*,*) 'mycall symbols ',ap(1:4)
if(len_trim(hiscall).gt.0) then
apmessage=mycall//" "//hiscall//" RRR"
call packmsg(apmessage,ap,itype,.false.)
if(itype.ne.1) ap=-1
apsymbols(3,1:9)=ap(1:9)
apsymbols(4,:)=ap
apmessage=mycall//" "//hiscall//" 73"
call packmsg(apmessage,ap,itype,.false.)
if(itype.ne.1) ap=-1
apsymbols(5,:)=ap
endif
endif
endif
qual=0. qual=0.
nbirdie=20 nbirdie=20
npct=50 npct=50
@ -71,28 +126,48 @@ subroutine extract(s3,nadd,mode65,ntrials,naggressive,ndepth,nflip, &
call graycode65(mr2sym,63,-1) !Remove gray code and interleaving call graycode65(mr2sym,63,-1) !Remove gray code and interleaving
call interleave63(mr2sym,-1) !from second-most-reliable symbols call interleave63(mr2sym,-1) !from second-most-reliable symbols
call interleave63(mr2prob,-1) call interleave63(mr2prob,-1)
ntry=0
!call gf64_osd(mrsym,mrprob,mr2sym,mr2prob,correct) npass=1 ! if ap decoding is disabled
call timer('ftrsd ',0) if(ljt65apon .and. len_trim(mycall).gt.0) then
param=0 npass=1+nappasses(nQSOProgress)
call ftrsd2(mrsym,mrprob,mr2sym,mr2prob,ntrials,correct,param,ntry) !write(*,*) 'ap is on: ',npass-1,'ap passes of types ',naptypes(nQSOProgress,:)
call timer('ftrsd ',1)
ncandidates=param(0)
nhard=param(1)
nsoft=param(2)
nerased=param(3)
rtt=0.001*param(4)
ntotal=param(5)
qual=0.001*param(7)
nd0=81
r0=0.87
if(naggressive.eq.10) then
nd0=83
r0=0.90
endif endif
if(ntotal.le.nd0 .and. rtt.le.r0) nft=1 do ipass=1,npass
ap=-1
ntype=0
if(ipass.gt.1) then
ntype=naptypes(nQSOProgress,ipass-1)
!write(*,*) 'ap pass, type ',ntype
ap=apsymbols(ntype,:)
if(count(ap.ge.0).eq.0) cycle ! don't bother if all ap symbols are -1
!write(*,'(12i3)') ap
endif
ntry=0
call timer('ftrsd ',0)
param=0
call ftrsdap(mrsym,mrprob,mr2sym,mr2prob,ap,ntrials,correct,param,ntry)
call timer('ftrsd ',1)
ncandidates=param(0)
nhard=param(1)
nsoft=param(2)
nerased=param(3)
rtt=0.001*param(4)
ntotal=param(5)
qual=0.001*param(7)
nd0=81
r0=0.87
if(naggressive.eq.10) then
nd0=83
r0=0.90
endif
if(ntotal.le.nd0 .and. rtt.le.r0) then
nft=1+ishft(ntype,2)
endif
if(nft.gt.0) exit
enddo
!write(*,*) nft
if(nft.eq.0 .and. iand(ndepth,32).eq.32) then if(nft.eq.0 .and. iand(ndepth,32).eq.32) then
qmin=2.0 - 0.1*naggressive qmin=2.0 - 0.1*naggressive
call timer('hint65 ',0) call timer('hint65 ',0)

227
lib/ftrsd/ftrsdap.c Normal file
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@ -0,0 +1,227 @@
/*
ftrsdap.c
A soft-decision decoder for the JT65 (63,12) Reed-Solomon code.
This decoding scheme is built around Phil Karn's Berlekamp-Massey
errors and erasures decoder. The approach is inspired by a number of
publications, including the stochastic Chase decoder described
in "Stochastic Chase Decoding of Reed-Solomon Codes", by Leroux et al.,
IEEE Communications Letters, Vol. 14, No. 9, September 2010 and
"Soft-Decision Decoding of Reed-Solomon Codes Using Successive Error-
and-Erasure Decoding," by Soo-Woong Lee and B. V. K. Vijaya Kumar.
Steve Franke K9AN and Joe Taylor K1JT
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <time.h>
#include <string.h>
#include "../ftrsd/rs2.h"
static void *rs;
void getpp_(int workdat[], float *pp);
void ftrsdap_(int mrsym[], int mrprob[], int mr2sym[], int mr2prob[],
int ap[], int* ntrials0, int correct[], int param[], int ntry[])
{
int rxdat[63], rxprob[63], rxdat2[63], rxprob2[63];
int workdat[63];
int indexes[63];
int era_pos[51];
int i, j, numera, nerr, nn=63;
int ntrials = *ntrials0;
int nhard=0,nhard_min=32768,nsoft=0,nsoft_min=32768;
int ntotal=0,ntotal_min=32768,ncandidates;
int nera_best=0;
float pp,pp1,pp2;
static unsigned int nseed;
// Power-percentage symbol metrics - composite gnnf/hf
int perr[8][8] = {
{ 4, 9, 11, 13, 14, 14, 15, 15},
{ 2, 20, 20, 30, 40, 50, 50, 50},
{ 7, 24, 27, 40, 50, 50, 50, 50},
{13, 25, 35, 46, 52, 70, 50, 50},
{17, 30, 42, 54, 55, 64, 71, 70},
{25, 39, 48, 57, 64, 66, 77, 77},
{32, 45, 54, 63, 66, 75, 78, 83},
{51, 58, 57, 66, 72, 77, 82, 86}};
// Initialize the KA9Q Reed-Solomon encoder/decoder
unsigned int symsize=6, gfpoly=0x43, fcr=3, prim=1, nroots=51;
rs=init_rs_int(symsize, gfpoly, fcr, prim, nroots, 0);
// Reverse the received symbol vectors for BM decoder
for (i=0; i<63; i++) {
rxdat[i]=mrsym[62-i];
rxprob[i]=mrprob[62-i];
rxdat2[i]=mr2sym[62-i];
rxprob2[i]=mr2prob[62-i];
}
// Set ap symbols and ap mask
for (i=0; i<12; i++) {
if(ap[i]>=0) {
rxdat[11-i]=ap[i];
rxprob2[11-i]=-1;
}
}
// Sort rxprob to find indexes of the least reliable symbols
int k, pass, tmp, nsym=63;
int probs[63];
for (i=0; i<63; i++) {
indexes[i]=i;
probs[i]=rxprob[i];
}
for (pass = 1; pass <= nsym-1; pass++) {
for (k = 0; k < nsym - pass; k++) {
if( probs[k] < probs[k+1] ) {
tmp = probs[k];
probs[k] = probs[k+1];
probs[k+1] = tmp;
tmp = indexes[k];
indexes[k] = indexes[k+1];
indexes[k+1] = tmp;
}
}
}
// See if we can decode using BM HDD, and calculate the syndrome vector.
memset(era_pos,0,51*sizeof(int));
numera=0;
memcpy(workdat,rxdat,sizeof(rxdat));
nerr=decode_rs_int(rs,workdat,era_pos,numera,1);
if( nerr >= 0 ) {
// Hard-decision decoding succeeded. Save codeword and some parameters.
nhard=0;
for (i=0; i<63; i++) {
if( workdat[i] != rxdat[i] ) nhard=nhard+1;
}
memcpy(correct,workdat,63*sizeof(int));
param[0]=0;
param[1]=nhard;
param[2]=0;
param[3]=0;
param[4]=0;
param[5]=0;
param[7]=1000*1000;
ntry[0]=0;
return;
}
/*
Hard-decision decoding failed. Try the FT soft-decision method.
Generate random erasure-locator vectors and see if any of them
decode. This will generate a list of "candidate" codewords. The
soft distance between each candidate codeword and the received
word is estimated by finding the largest (pp1) and second-largest
(pp2) outputs from a synchronized filter-bank operating on the
symbol spectra, and using these to decide which candidate
codeword is "best".
*/
nseed=1; //Seed for random numbers
float ratio;
int thresh, nsum;
int thresh0[63];
ncandidates=0;
nsum=0;
int ii,jj;
for (i=0; i<nn; i++) {
nsum=nsum+rxprob[i];
j = indexes[62-i];
if( rxprob2[j]>=0 ) {
ratio = (float)rxprob2[j]/((float)rxprob[j]+0.01);
ii = 7.999*ratio;
jj = (62-i)/8;
thresh0[i] = 1.3*perr[ii][jj];
} else {
thresh0[i] = 0.0;
}
//printf("%d %d %d\n",i,j,rxdat[i]);
}
if(nsum<=0) return;
pp1=0.0;
pp2=0.0;
for (k=1; k<=ntrials; k++) {
memset(era_pos,0,51*sizeof(int));
memcpy(workdat,rxdat,sizeof(rxdat));
/*
Mark a subset of the symbols as erasures.
Run through the ranked symbols, starting with the worst, i=0.
NB: j is the symbol-vector index of the symbol with rank i.
*/
numera=0;
for (i=0; i<nn; i++) {
j = indexes[62-i];
thresh=thresh0[i];
long int ir;
// Generate a random number ir, 0 <= ir < 100 (see POSIX.1-2001 example).
nseed = nseed * 1103515245 + 12345;
ir = (unsigned)(nseed/65536) % 32768;
ir = (100*ir)/32768;
if((ir < thresh ) && numera < 51) {
era_pos[numera]=j;
numera=numera+1;
}
}
nerr=decode_rs_int(rs,workdat,era_pos,numera,0);
if( nerr >= 0 ) {
// We have a candidate codeword. Find its hard and soft distance from
// the received word. Also find pp1 and pp2 from the full array
// s3(64,63) of synchronized symbol spectra.
ncandidates=ncandidates+1;
nhard=0;
nsoft=0;
for (i=0; i<63; i++) {
if(workdat[i] != rxdat[i]) {
nhard=nhard+1;
if(workdat[i] != rxdat2[i]) {
nsoft=nsoft+rxprob[i];
}
}
}
nsoft=63*nsoft/nsum;
ntotal=nsoft+nhard;
getpp_(workdat,&pp);
if(pp>pp1) {
pp2=pp1;
pp1=pp;
nsoft_min=nsoft;
nhard_min=nhard;
ntotal_min=ntotal;
memcpy(correct,workdat,63*sizeof(int));
nera_best=numera;
ntry[0]=k;
} else {
if(pp>pp2 && pp!=pp1) pp2=pp;
}
if(nhard_min <= 41 && ntotal_min <= 71) break;
}
if(k == ntrials) ntry[0]=k;
}
param[0]=ncandidates;
param[1]=nhard_min;
param[2]=nsoft_min;
param[3]=nera_best;
param[4]=1000.0*pp2/pp1;
param[5]=ntotal_min;
param[6]=ntry[0];
param[7]=1000.0*pp2;
param[8]=1000.0*pp1;
if(param[0]==0) param[2]=-1;
return;
}

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@ -490,8 +490,9 @@ contains
enddo enddo
nadd=nsum*ismo nadd=nsum*ismo
call extract(s3,nadd,mode65,ntrials,naggressive,ndepth,nflip,mycall, & call extract(s3c,nadd,mode65,ntrials,naggressive,ndepth,nflip,mycall, &
hiscall,hisgrid,nexp_decode,ncount,nhist,decoded,ltext,nft,qual) hiscall,hisgrid,nQSOProgress,ljt65apon,nexp_decode,ncount,nhist, &
avemsg,ltext,nftt,qual)
if(nftt.eq.1) then if(nftt.eq.1) then
nsmo=ismo nsmo=ismo
param(9)=nsmo param(9)=nsmo