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sdrangel/plugins/channelrx/demoddatv/leansdr/dvbs2.h

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// This file is part of LeanSDR Copyright (C) 2016-2019 <pabr@pabr.org>.
// See the toplevel README for more information.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
// Latest updates:
// | S2: Revert to tracking all symbols. pabr committed on Mar 6, 2019
// | Cleanup: Remove debug code. pabr committed on Mar 6, 2019
// | S2: Dummy PLFRAME handling pabr committed on Mar 26, 2019
// | S2: Preliminary support for GSE pabr committed on Mar 26, 2019
// | leandvbtx: Signal S2 MATYPE as TS. pabr committed on Mar 26, 2019
// | DVB-S2 VCM support, suitable for ACM reception (not MIS). pabr committed on Nov 24, 2019
// | Remove unused constants. pabr committed on Dec 4, 2019
// | S2 RX: Capture TED decision history in sampler_state. pabr committed on Dec 5, 2019
// | S2 RX: Print error rate on PLS symbols. pabr committed on Dec 5, 2019
// | New DVB-S2 receiver with PL-based carrier recovery. modcod/framesize filtering for VCM. pabr committed on Jan 9, 2020
// skip Soft-decoding of S2 PLSCODE. pabr committed on Jan 16, 2020
// skip Validate PLHEADER soft-decoding when DEBUG_CARRIER==1. pabr committed on Jan 17, 2020
// | Cleanup scope of some S2 constants. pabr committed on Apr 29, 2020
// skip Fix overflow to state_out stream. pabr committed on Apr 29, 2020
// | S2 deframer: Set TEI bit on TS packets with bad CRC8. pabr committed on Jul 29, 2020
#ifndef LEANSDR_DVBS2_H
#define LEANSDR_DVBS2_H
/*
#include "leansdr/bch.h"
#include "leansdr/crc.h"
#include "leansdr/dvb.h"
#include "leansdr/ldpc.h"
#include "leansdr/sdr.h"
#include "leansdr/softword.h"
*/
#include <stdlib.h>
#include <deque>
#include <bitset>
#include "bch.h"
#include "crc.h"
#include "dvb.h"
#include "softword.h"
#include "ldpc.h"
#include "sdr.h"
#ifdef LINUX
#include <signal.h>
#include <sys/wait.h>
#include "ldpctool/layered_decoder.h"
#include "ldpctool/testbench.h"
#include "ldpctool/algorithms.h"
#endif
namespace leansdr
{
// S2 THRESHOLDS (for comparing demodulators)
static const uint32_t S2_MAX_ERR_SOF = 13; // 26 bits
static const uint64_t S2_MAX_ERR_PLSCODE = 8; // 64 bits, dmin=32
static const int pilot_length = 36;
// S2 SOF
// EN 302 307-1 section 5.5.2.1 SOF field
template <typename T>
struct s2_sof
{
static const uint32_t VALUE = 0x18d2e82;
static const uint32_t MASK = 0x3ffffff;
static const int LENGTH = 26;
complex<T> symbols[LENGTH];
s2_sof()
{
for (int s = 0; s < LENGTH; ++s)
{
int angle = ((VALUE >> (LENGTH - 1 - s)) & 1) * 2 + (s & 1); // pi/2-BPSK
symbols[s].re = cstln_amp * cosf(M_PI / 4 + 2 * M_PI * angle / 4);
symbols[s].im = cstln_amp * sinf(M_PI / 4 + 2 * M_PI * angle / 4);
}
}
}; // s2_sof
// S2 PLS CODES
// Precomputes the PLS code sequences.
// EN 302 307-1 section 5.5.2.4 PLS code
template <typename T>
struct s2_plscodes
{
// PLS index format MODCOD[4:0]|SHORTFRAME|PILOTS
static const int COUNT = 128;
static const int LENGTH = 64;
uint64_t codewords[COUNT];
complex<T> symbols[COUNT][LENGTH];
s2_plscodes()
{
uint32_t G[6] = {0x55555555,
0x33333333,
0x0f0f0f0f,
0x00ff00ff,
0x0000ffff,
0xffffffff};
for (int index = 0; index < COUNT; ++index)
{
uint32_t y = 0;
for (int row = 0; row < 6; ++row)
{
if ((index >> (6 - row)) & 1) {
y ^= G[row];
}
}
uint64_t code = 0;
for (int bit = 31; bit >= 0; --bit)
{
int yi = (y >> bit) & 1;
if (index & 1) {
code = (code << 2) | (yi << 1) | (yi ^ 1);
} else {
code = (code << 2) | (yi << 1) | yi;
}
}
// Scrambling
code ^= SCRAMBLING;
// Store precomputed codeword.
codewords[index] = code;
// Also store as symbols.
for (int i = 0; i < LENGTH; ++i)
{
int yi = (code >> (LENGTH - 1 - i)) & 1;
int nyi = yi ^ (i & 1);
symbols[index][i].re = cstln_amp * (1 - 2 * nyi) / sqrtf(2);
symbols[index][i].im = cstln_amp * (1 - 2 * yi) / sqrtf(2);
}
}
}
static const uint64_t SCRAMBLING = 0x719d83c953422dfa;
}; // s2_plscodes
static const int PILOT_LENGTH = 36;
// Date about pilots.
// Mostly for consistency with s2_sof and s2_plscodes.
template<typename T>
struct s2_pilot
{
static const int LENGTH = PILOT_LENGTH;
complex<T> symbol;
s2_pilot() {
symbol.re = symbol.im = cstln_amp*0.707107;
}
}; // s2_pilot
// S2 SCRAMBLING
// Precomputes the symbol rotations for PL scrambling.
// EN 302 307-1 section 5.5.4 Physical layer scrambling
struct s2_scrambling
{
uint8_t Rn[131072]; // 0..3 (* 2pi/4)
s2_scrambling(int codenum = 0)
{
uint32_t stx = 0x00001, sty = 0x3ffff;
// x starts at codenum, wraps at index 2^18-1 by design
for (int i = 0; i < codenum; ++i) {
stx = lfsr_x(stx);
}
// First half of sequence is LSB of scrambling angle
for (int i = 0; i < 131072; ++i)
{
int zn = (stx ^ sty) & 1;
Rn[i] = zn;
stx = lfsr_x(stx);
sty = lfsr_y(sty);
}
// Second half is MSB
for (int i = 0; i < 131072; ++i)
{
int zn = (stx ^ sty) & 1;
Rn[i] |= zn << 1;
stx = lfsr_x(stx);
sty = lfsr_y(sty);
}
}
uint32_t lfsr_x(uint32_t X)
{
int bit = ((X >> 7) ^ X) & 1;
return ((bit << 18) | X) >> 1;
}
uint32_t lfsr_y(uint32_t Y)
{
int bit = ((Y >> 10) ^ (Y >> 7) ^ (Y >> 5) ^ Y) & 1;
return ((bit << 18) | Y) >> 1;
}
}; // s2_scrambling
// S2 BBSCRAMBLING
// Precomputes the xor pattern for baseband scrambling.
// EN 302 307-1 section 5.2.2 BB scrambling
struct s2_bbscrambling
{
s2_bbscrambling()
{
uint16_t st = 0x00a9; // 000 0000 1010 1001 (Fig 5 reversed)
for (unsigned int i = 0; i < sizeof(pattern); ++i)
{
uint8_t out = 0;
for (int n = 8; n--;)
{
int bit = ((st >> 13) ^ (st >> 14)) & 1; // Taps
out = (out << 1) | bit; // MSB first
st = (st << 1) | bit; // Feedback
}
pattern[i] = out;
}
}
void transform(const uint8_t *in, int bbsize, uint8_t *out)
{
for (int i = 0; i < bbsize; ++i) {
out[i] = in[i] ^ pattern[i];
}
}
private:
uint8_t pattern[58192]; // Values 0..3
}; // s2_bbscrambling
// S2 PHYSICAL LAYER SIGNALLING
struct s2_pls
{
int modcod; // 0..31
bool sf;
bool pilots;
int framebits() const {
return sf ? 16200 : 64800;
}
bool is_dummy() {
return (modcod==0);
}
};
static const int PLSLOT_LENGTH = 90;
template <typename SOFTSYMB>
struct plslot
{
static const int LENGTH = PLSLOT_LENGTH;
bool is_pls;
union {
s2_pls pls;
SOFTSYMB symbols[LENGTH];
};
};
// EN 302 307-1 section 5.5.2.2 MODCOD field
// EN 302 307-1 section 6 Error performance
const struct modcod_info
{
static const int MIN_SLOTS_PER_FRAME = 144;
static const int MIN_SYMBOLS_PER_FRAME =
(1+MIN_SLOTS_PER_FRAME) * PLSLOT_LENGTH;
static const int MAX_SLOTS_PER_FRAME = 360;
static const int MAX_SYMBOLS_PER_FRAME =
(1 + MAX_SLOTS_PER_FRAME) * PLSLOT_LENGTH +
((MAX_SLOTS_PER_FRAME - 1) / 16) * PILOT_LENGTH;
int nslots_nf; // Number of 90-symbol slots per normal frame
int nsymbols; // Symbols in the constellation
cstln_base::predef c;
code_rate rate;
// Ideal Es/N0 for normal frames
// EN 302 307 section 6 Error performance
float esn0_nf;
// Radii for APSK
// EN 302 307, section 5.4.3, Table 9
// EN 302 307, section 5.4.4, Table 10
float g1, g2, g3;
} modcod_infos[32] = {
{0, 0, cstln_base::BPSK, FEC12, 0.0, 0.0, 0.0, 0.0},
// 1 - 11
{360, 4, cstln_base::QPSK, FEC14, -2.35, 0.0, 0.0, 0.0},
{360, 4, cstln_base::QPSK, FEC13, -1.24, 0.0, 0.0, 0.0},
{360, 4, cstln_base::QPSK, FEC25, -0.30, 0.0, 0.0, 0.0},
{360, 4, cstln_base::QPSK, FEC12, 1.00, 0.0, 0.0, 0.0},
{360, 4, cstln_base::QPSK, FEC35, 2.23, 0.0, 0.0, 0.0},
{360, 4, cstln_base::QPSK, FEC23, 3.10, 0.0, 0.0, 0.0},
{360, 4, cstln_base::QPSK, FEC34, 4.03, 0.0, 0.0, 0.0},
{360, 4, cstln_base::QPSK, FEC45, 4.68, 0.0, 0.0, 0.0},
{360, 4, cstln_base::QPSK, FEC56, 5.18, 0.0, 0.0, 0.0},
{360, 4, cstln_base::QPSK, FEC89, 6.20, 0.0, 0.0, 0.0},
{360, 4, cstln_base::QPSK, FEC910, 6.42, 0.0, 0.0, 0.0},
// 12 - 17
{240, 8, cstln_base::PSK8, FEC35, 5.50, 0.0, 0.0, 0.0},
{240, 8, cstln_base::PSK8, FEC23, 6.62, 0.0, 0.0, 0.0},
{240, 8, cstln_base::PSK8, FEC34, 7.91, 0.0, 0.0, 0.0},
{240, 8, cstln_base::PSK8, FEC56, 9.35, 0.0, 0.0, 0.0},
{240, 8, cstln_base::PSK8, FEC89, 10.69, 0.0, 0.0, 0.0},
{240, 8, cstln_base::PSK8, FEC910, 10.98, 0.0, 0.0, 0.0},
// 18 - 23
{180, 16, cstln_base::APSK16, FEC23, 8.97, 3.15, 0.0, 0.0},
{180, 16, cstln_base::APSK16, FEC34, 10.21, 2.85, 0.0, 0.0},
{180, 16, cstln_base::APSK16, FEC45, 11.03, 2.75, 0.0, 0.0},
{180, 16, cstln_base::APSK16, FEC56, 11.61, 2.70, 0.0, 0.0},
{180, 16, cstln_base::APSK16, FEC89, 12.89, 2.60, 0.0, 0.0},
{180, 16, cstln_base::APSK16, FEC910, 13.13, 2.57, 0.0, 0.0},
// 24 - 28
{144, 32, cstln_base::APSK32, FEC34, 12.73, 2.84, 5.27, 0.0},
{144, 32, cstln_base::APSK32, FEC45, 13.64, 2.72, 4.87, 0.0},
{144, 32, cstln_base::APSK32, FEC56, 14.28, 2.64, 4.64, 0.0},
{144, 32, cstln_base::APSK32, FEC89, 15.69, 2.54, 4.33, 0.0},
{144, 32, cstln_base::APSK32, FEC910, 16.05, 2.53, 4.30, 0.0},
// 29 - 31
{0, 0, cstln_base::BPSK, FEC12, 0.0, 0.0, 0.0, 0.0},
{0, 0, cstln_base::BPSK, FEC12, 0.0, 0.0, 0.0, 0.0},
{0, 0, cstln_base::BPSK, FEC12, 0.0, 0.0, 0.0, 0.0}
};
// Assert that a MODCOD number is valid
const modcod_info *check_modcod(int m)
{
if (m < 0 || m > 31) {
fail("Invalid MODCOD number");
}
const modcod_info *r = &modcod_infos[m];
if (!r->nslots_nf) {
fail("Unsupported MODCOD");
}
return r;
}
// S2 FRAME TRANSMITTER
template <typename T>
struct s2_frame_transmitter : runnable
{
s2_frame_transmitter(
scheduler *sch,
pipebuf<plslot<hard_ss>> &_in,
pipebuf<complex<T>> &_out
) :
runnable(sch, "S2 frame transmitter"),
in(_in),
out(_out, modcod_info::MAX_SYMBOLS_PER_FRAME)
{
float amp = cstln_amp / sqrtf(2);
qsymbols[0].re = +amp;
qsymbols[0].im = +amp;
qsymbols[1].re = +amp;
qsymbols[1].im = -amp;
qsymbols[2].re = -amp;
qsymbols[2].im = +amp;
qsymbols[3].re = -amp;
qsymbols[3].im = -amp;
// Clear the constellation cache.
for (int i = 0; i < 32; ++i) {
pcsymbols[i] = nullptr;
}
}
~s2_frame_transmitter()
{
}
void run()
{
while (in.readable() >= 1)
{
plslot<hard_ss> *pin = in.rd();
if (!pin->is_pls) {
fail("Expected PLS pseudo-slot");
}
s2_pls *pls = &pin->pls;
const modcod_info *mcinfo = check_modcod(pls->modcod);
int nslots = (pls->sf ? mcinfo->nslots_nf / 4 : mcinfo->nslots_nf);
if (in.readable() < 1 + nslots) {
break;
}
// Require room for BBHEADER + slots + optional pilots.
int nsymbols = ((1 + nslots) * plslot<hard_ss>::LENGTH +
(pls->pilots ? ((nslots - 1) / 16) * pilot_length : 0));
if (out.writable() < nsymbols) {
break;
}
int nw = run_frame(pls, mcinfo, pin + 1, nslots, out.wr());
if (nw != nsymbols) {
fail("Bug: s2_frame_transmitter overflow");
}
in.read(1 + nslots);
out.written(nsymbols);
}
}
int run_frame(
s2_pls *pls,
const modcod_info *mcinfo,
const plslot<hard_ss> *pin,
int nslots,
complex<T> *pout
)
{
complex<T> *pout0 = pout; // For sanity check
// PLHEADER: SOF AND PLSCODE
// EN 302 307-1 section 5.5.2 PL signalling
memcpy(pout, sof.symbols, sof.LENGTH * sizeof(*pout));
pout += sof.LENGTH;
int pls_index = (pls->modcod << 2) | (pls->sf << 1) | pls->pilots;
memcpy(pout, plscodes.symbols[pls_index], plscodes.LENGTH * sizeof(*pout));
pout += plscodes.LENGTH;
complex<T> *csymbols = get_csymbols(pls->modcod);
// Slots and pilots
int till_next_pilot = pls->pilots ? 16 : nslots;
uint8_t *scr = &scrambling.Rn[0];
for (int S = 0; S < nslots; ++S, ++pin, --till_next_pilot)
{
if (till_next_pilot == 0)
{
// Send pilot
for (int s = 0; s < pilot_length; ++s, ++scr, ++pout) {
scramble(&qsymbols[0], *scr, pout);
}
till_next_pilot = 16;
}
// Send slot
if (pin->is_pls) {
fail("s2_frame_transmitter: bad input sequence");
}
const hard_ss *ps = pin->symbols;
for (int s = 0; s < pin->LENGTH; ++s, ++ps, ++scr, ++pout) {
scramble(&csymbols[*ps], *scr, pout);
}
}
return pout - pout0;
}
inline void scramble(const complex<T> *src, uint8_t r, complex<T> *dst)
{
switch (r)
{
case 3:
dst->re = src->im;
dst->im = -src->re;
break;
case 2:
dst->re = -src->re;
dst->im = -src->im;
break;
case 1:
dst->re = -src->im;
dst->im = src->re;
break;
default:
*dst = *src;
}
}
private:
pipereader<plslot<hard_ss>> in;
pipewriter<complex<T>> out;
complex<T> *pcsymbols[32]; // Constellations in use, indexed by modcod
complex<T> *get_csymbols(int modcod)
{
if (!pcsymbols[modcod])
{
const modcod_info *mcinfo = check_modcod(modcod);
if (sch->debug)
{
fprintf(
stderr,
"Building constellation %s ratecode %d\n",
cstln_base::names[mcinfo->c],
mcinfo->rate
);
}
// TBD Different Es/N0 for short frames ?
cstln_lut<hard_ss,256> cstln(
mcinfo->c,
mcinfo->esn0_nf,
mcinfo->g1,
mcinfo->g2,
mcinfo->g3
);
pcsymbols[modcod] = new complex<T>[cstln.nsymbols];
for ( int s=0; s<cstln.nsymbols; ++s )
{
pcsymbols[modcod][s].re = cstln.symbols[s].re;
pcsymbols[modcod][s].im = cstln.symbols[s].im;
}
}
return pcsymbols[modcod];
}
complex<T> qsymbols[4]; // RMS cstln_amp
s2_sof<T> sof;
s2_plscodes<T> plscodes;
s2_scrambling scrambling;
}; // s2_frame_transmitter
// S2 FRAME RECEIVER
#define TEST_DIVERSITY 0
template<typename T, typename SOFTSYMB>
struct s2_frame_receiver : runnable
{
sampler_interface<T> *sampler;
int meas_decimation;
float Ftune; // Tuning bias in cycles per symbol
bool allow_drift; // Unbounded carrier tracking
float omega0; // Samples per symbol
bool strongpls; // PL symbols at max amplitude (default: RMS)
uint32_t modcods; // Bitmask of desired modcods
uint8_t framesizes; // Bitmask of desired frame sizes
bool fastlock; // Synchronize more agressively
bool fastdrift; // Carrier drift faster than pilots
float freq_tol; // Tolerance on carrier frequency
float sr_tol; // Tolerance on symbol rate
s2_frame_receiver(
scheduler *sch,
sampler_interface<T> *_sampler,
pipebuf< complex<T> > &_in,
pipebuf< plslot<SOFTSYMB> > &_out,
pipebuf<float> *_freq_out=NULL,
pipebuf<float> *_ss_out=NULL,
pipebuf<float> *_mer_out=NULL,
pipebuf< complex<float> > *_cstln_out=NULL,
pipebuf< complex<float> > *_cstln_pls_out=NULL,
pipebuf< complex<float> > *_symbols_out=NULL,
pipebuf<int> *_state_out=NULL
) :
runnable(sch, "S2 frame receiver"),
sampler(_sampler),
meas_decimation(1048576),
Ftune(0),
allow_drift(false),
strongpls(false),
modcods(0xffffffff),
framesizes(0x03),
fastlock(false),
fastdrift(false),
freq_tol(0.25),
sr_tol(100e-6),
cstln(NULL),
in(_in), out(_out,1+modcod_info::MAX_SLOTS_PER_FRAME),
meas_count(0),
freq_out(opt_writer(_freq_out)),
ss_out(opt_writer(_ss_out)),
mer_out(opt_writer(_mer_out)),
cstln_out(opt_writer(_cstln_out,1024)),
cstln_pls_out(opt_writer(_cstln_pls_out,1024)),
symbols_out(opt_writer(_symbols_out, modcod_info::MAX_SYMBOLS_PER_FRAME)),
state_out(opt_writer(_state_out)),
first_run(true),
scrambling(0),
pls_total_errors(0),
pls_total_count(0),
m_modcodType(-1),
m_modcodRate(-1),
diffs(nullptr),
sspilots(nullptr)
{
// Constellation for PLS
qpsk = new cstln_lut<SOFTSYMB,256>(cstln_base::QPSK);
// Clear the constellation cache.
for (int i=0; i<32; ++i) {
cstlns[i] = NULL;
}
#if TEST_DIVERSITY
fprintf(stderr, "** DEBUG: Diversity test mode (slower)\n");
#endif
}
~s2_frame_receiver()
{
delete qpsk;
for (int i=0; i<32; ++i)
{
if (cstlns[i]) {
delete cstlns[i];
}
}
if (diffs) {
delete[] diffs;
}
if (sspilots) {
delete[] sspilots;
}
}
enum {
FRAME_DETECT, // Looking for PLHEADER
FRAME_PROBE, // Aligned with PLHEADER, ready to recover carrier
FRAME_LOCKED, // Demodulating
} state;
// sampler_state holds the entire state of the PLL.
// Useful for looking ahead (e.g. next pilots/SOF) then rewinding.
struct sampler_state {
complex<T> *p; // Pointer to samples (update when entering run())
float mu; // Time of next symbol, counted from p
float omega; // Samples per symbol
float gain; // Scaling factor toward cstln_amp
float ph16; // Carrier phase at next symbol (cycles * 65536)
float fw16; // Carrier frequency (cycles per symbol * 65536)
uint8_t *scr; // Position in scrambling sequence for next symbol
void normalize() {
ph16 = fmodf(ph16, 65536.0f); // Rounding direction irrelevant
}
void skip_symbols(int ns)
{
mu += omega * ns;
p += (int)floorf(mu);
mu -= floorf(mu);
ph16 += fw16 * ns;
normalize();
scr += ns;
}
char *format() {
static char buf[256];
sprintf(
buf,
"%9.2lf %+6.0f ppm %+3.0f ° %f",
(double)((p-(complex<T>*)NULL)&262143)+mu, // Arbitrary wrap
fw16*1e6/65536,
fmodfs(ph16,65536.0f)*360/65536,
gain
);
return buf;
}
};
float min_freqw16, max_freqw16;
// State during FRAME_SEARCH and FRAME_LOCKED
sampler_state ss_cache;
void run()
{
if (strongpls) {
fail("--strongpls is broken.");
}
// Require enough samples to detect one plheader,
// TBD margin ?
int min_samples = (1 + modcod_info::MAX_SYMBOLS_PER_FRAME +
sof.LENGTH+plscodes.LENGTH)*omega0 * 2;
while (in.readable() >= min_samples + sampler->readahead() &&
out.writable() >= 1+modcod_info::MAX_SLOTS_PER_FRAME &&
opt_writable(freq_out, 1) &&
opt_writable(ss_out, 1) &&
opt_writable(mer_out, 1) &&
opt_writable(symbols_out, modcod_info::MAX_SYMBOLS_PER_FRAME) &&
opt_writable(state_out, 1))
{
if (first_run)
{
enter_frame_detect();
first_run = false;
}
switch ( state )
{
case FRAME_DETECT:
run_frame_detect();
break;
case FRAME_PROBE:
run_frame_probe();
break;
case FRAME_LOCKED:
run_frame_locked();
break;
}
}
}
// State transtion
void enter_frame_detect()
{
state = FRAME_DETECT;
// Setup sampler for interpolation only.
ss_cache.fw16 = 65536 * Ftune;
ss_cache.ph16 = 0;
ss_cache.mu = 0;
ss_cache.gain = 1;
ss_cache.omega = omega0;
// Set frequency tracking boundaries around tuning frequency.
if (allow_drift)
{
// Track across the whole baseband.
min_freqw16 = ss_cache.fw16 - omega0*65536;
max_freqw16 = ss_cache.fw16 + omega0*65536;
}
else
{
min_freqw16 = ss_cache.fw16 - freq_tol*65536.0;
max_freqw16 = ss_cache.fw16 + freq_tol*65536.0;
}
opt_write(state_out, 0);
if (sch->debug) {
fprintf(stderr, "DETECT\n");
}
if (fastlock || first_run)
{
discard = 0;
}
else
{
// Discard some data so that CPU usage during PLHEADER detection
// is at same level as during steady-state demodulation.
// This has no effect if the first detection is successful.
float duty_factor = 5;
discard = modcod_info::MAX_SYMBOLS_PER_FRAME * omega0 * (duty_factor+drand48()-0.5);
}
}
long discard;
void run_frame_detect()
{
if ( discard )
{
size_t d = std::min(discard, in.readable());
in.read(d);
discard -= d;
return;
}
sampler->update_freq(ss_cache.fw16/omega0);
const int search_range = modcod_info::MAX_SYMBOLS_PER_FRAME;
ss_cache.p = in.rd();
find_plheader(&ss_cache, search_range);
#if DEBUG_CARRIER
fprintf(stderr, "CARRIER diffcorr: %.0f%% %s\n",
q*100, ss_cache.format());
#endif
in.read(ss_cache.p-in.rd());
enter_frame_probe();
}
void enter_frame_probe()
{
if (sch->debug) {
fprintf(stderr, "PROBE\n");
}
state = FRAME_PROBE;
}
void run_frame_probe() {
return run_frame_probe_locked();
}
void enter_frame_locked()
{
state = FRAME_LOCKED;
if (sch->debug) {
fprintf(stderr, "LOCKED\n");
}
opt_write(state_out, 1);
}
void run_frame_locked() {
return run_frame_probe_locked();
}
// Process one frame.
// Perform additional carrier estimation if state==FRAME_PROBE.
void run_frame_probe_locked()
{
complex<float> *psampled; // Data symbols (one per slot)
if (cstln_out && cstln_out->writable()>=1024) {
psampled = cstln_out->wr();
} else {
psampled = NULL;
}
complex<float> *psampled_pls; // PLHEADER symbols
if (cstln_pls_out && cstln_pls_out->writable()>=1024) {
psampled_pls = cstln_pls_out->wr();
} else {
psampled_pls = NULL;
}
#if TEST_DIVERSITY
complex<float> *psymbols = symbols_out ? symbols_out->wr() : NULL;
float scale_symbols = 1.0 / cstln_amp;
#endif
sampler_state ss = ss_cache;
ss.p = in.rd();
ss.normalize();
sampler->update_freq(ss.fw16/omega0);
#if DEBUG_CARRIER
fprintf(stderr, "CARRIER frame: %s\n", ss.format());
#endif
// Interpolate PLHEADER.
const int PLH_LENGTH = sof.LENGTH + plscodes.LENGTH;
complex<float> plh_symbols[PLH_LENGTH];
for (int s=0; s<PLH_LENGTH; ++s)
{
complex<float> p = interp_next(&ss) * ss.gain;
plh_symbols[s] = p;
if (psampled_pls) {
*psampled_pls++ = p;
}
}
// Decode SOF.
uint32_t sof_bits = 0;
// Optimization with half loop and even/odd processing in a single step
for (int i = 0; i < sof.LENGTH/2; ++i)
{
complex<float> p0 = plh_symbols[2*i];
complex<float> p1 = plh_symbols[2*i+1];
float d0 = p0.im + p0.re;
float d1 = p1.im - p1.re;
sof_bits = (sof_bits<<2) | ((d0<0)<<1) | (d1<0);
}
uint32_t sof_errors = hamming_weight(sof_bits ^ sof.VALUE);
pls_total_errors += sof_errors;
pls_total_count += sof.LENGTH;
if (sof_errors >= S2_MAX_ERR_SOF)
{
if (sch->debug2) {
fprintf(stderr, "Too many errors in SOF (%u/26)\n", sof_errors);
}
in.read(ss.p-in.rd());
enter_frame_detect();
return;
}
// Decode PLSCODE.
uint64_t plscode = 0;
// Optimization with half loop and even/odd processing in a single step
for (int i=0; i<plscodes.LENGTH/2; ++i)
{
complex<float> p0 = plh_symbols[sof.LENGTH+2*i];
complex<float> p1 = plh_symbols[sof.LENGTH+2*i+1];
float d0 = p0.im + p0.re;
float d1 = p1.im - p1.re;
plscode = (plscode<<2) | ((d0<0)<<1) | (d1<0);
}
uint32_t plscode_errors = plscodes.LENGTH + 1;
int plscode_index = -1; // Avoid compiler warning.
// TBD: Optimization?
#if 1
for (int i = 0; i < plscodes.COUNT; ++i)
{
// number of different bits from codeword
uint32_t e = std::bitset<64>(plscode ^ plscodes.codewords[i]).count();
if (e < plscode_errors )
{
plscode_errors = e;
plscode_index = i;
}
}
#else
uint64_t pls_candidates[plscodes.COUNT];
std::fill(pls_candidates, pls_candidates + plscodes.COUNT, plscode);
std::transform(pls_candidates, pls_candidates + plscodes.COUNT, plscodes.codewords, pls_candidates, [](uint64_t x, uint64_t y) {
return hamming_weight(x^y); // number of different bits with codeword
});
uint64_t *pls_elected = std::min_element(pls_candidates, pls_candidates + plscodes.COUNT); // choose the one with lowest difference
plscode_errors = *pls_elected;
plscode_index = pls_elected - pls_candidates;
#endif
pls_total_errors += plscode_errors;
pls_total_count += plscodes.LENGTH;
if (plscode_errors >= S2_MAX_ERR_PLSCODE)
{
if (sch->debug2) {
fprintf(stderr, "Too many errors in plscode (%u)\n", plscode_errors);
}
in.read(ss.p-in.rd());
enter_frame_detect();
return;
}
// ss now points to first data slot.
ss.scr = scrambling.Rn;
complex<float> plh_expected[PLH_LENGTH];
std::copy(sof.symbols, sof.symbols + sof.LENGTH, plh_expected);
std::copy(plscodes.symbols[plscode_index], plscodes.symbols[plscode_index] + plscodes.LENGTH, &plh_expected[sof.LENGTH]);
if ( state == FRAME_PROBE )
{
// Carrier frequency from differential detector is still not reliable.
// Use known PLH symbols to improve.
match_freq(plh_expected, plh_symbols, PLH_LENGTH, &ss);
#if DEBUG_CARRIER
fprintf(stderr, "CARRIER freq: %s\n", ss.format());
#endif
}
// Use known PLH symbols to estimate carrier phase and amplitude.
float mer2 = match_ph_amp(plh_expected, plh_symbols, PLH_LENGTH, &ss);
float mer = 10*log10f(mer2);
#if DEBUG_CARRIER
fprintf(stderr, "CARRIER plheader: %s MER %.1f dB\n", ss.format(), mer);
#endif
// Parse PLSCODE.
s2_pls pls;
pls.modcod = plscode_index >> 2; // Guaranteed 0..31
pls.sf = plscode_index & 2;
pls.pilots = plscode_index & 1;
plslot<SOFTSYMB> *pout=out.wr(), *pout0 = pout;
if (sch->debug2)
{
fprintf(
stderr,
"PLS: mc=%2d, sf=%d, pilots=%d (%2u/90) %4.1f dB ",
pls.modcod,
pls.sf,
pls.pilots,
sof_errors + plscode_errors,
mer
);
}
// Determine contents of frame.
int S; // Data slots in this frame
cstln_lut<SOFTSYMB,256> *dcstln; // Constellation for data slots
if (pls.is_dummy())
{
S = 36;
dcstln = qpsk;
}
else
{
const modcod_info *mcinfo = &modcod_infos[pls.modcod];
if (! mcinfo->nslots_nf)
{
fprintf(stderr, "Unsupported or corrupted MODCOD\n");
in.read(ss.p-in.rd());
enter_frame_detect();
return;
}
if (mer < mcinfo->esn0_nf - 1.0f)
{
// False positive from PLHEADER detection.
if ( sch->debug ) fprintf(stderr, "Insufficient MER\n");
in.read(ss.p-in.rd());
enter_frame_detect();
return;
}
if (pls.sf && mcinfo->rate==FEC910)
{ // TBD use fec_infos
fprintf(stderr, "Unsupported or corrupted FEC\n");
in.read(ss.p-in.rd());
enter_frame_detect();
return;
}
// Store current MODCOD info
if (mcinfo->c != m_modcodType) {
m_modcodType = mcinfo->c;
}
if (mcinfo->rate != m_modcodRate) {
m_modcodRate = mcinfo->rate;
}
S = pls.sf ? mcinfo->nslots_nf/4 : mcinfo->nslots_nf;
// Constellation for data slots.
dcstln = get_cstln(pls.modcod);
cstln = dcstln; // Used by GUI
cstln->m_rateCode = (int) mcinfo->rate;
cstln->m_typeCode = (int) mcinfo->c;
cstln->m_setByModcod = true;
// Output special slot with PLS information.
pout->is_pls = true;
pout->pls = pls;
++pout;
}
// Now we know the frame structure.
// Estimate carrier over known symbols.
#if DEBUG_LOOKAHEAD
static int plh_counter = 0; // For debugging only
fprintf(stderr, "\nLOOKAHEAD %d PLH sr %+3.0f %s %.1f dB\n",
plh_counter, (1-ss.omega/omega0)*1e6,
ss.format(), 10*log10f(mer2));
#endif
// Next SOF
sampler_state ssnext;
{
ssnext = ss;
int ns = (S*PLSLOT_LENGTH +
(pls.pilots?((S-1)/16)*pilot.LENGTH:0));
// Find next SOP at expected position +- tolerance on symbol rate.
int ns_tol = lrintf(ns*sr_tol);
ssnext.omega = omega0;
ssnext.skip_symbols(ns-ns_tol);
find_plheader(&ssnext, ns_tol*2);
// Don't trust frequency from differential correlator.
// Our current estimate should be better.
ssnext.fw16 = ss.fw16;
interp_match_sof(&ssnext);
#if DEBUG_CARRIER
fprintf(stderr, "\nCARRIER next: %.0f%% %s %.1f dB\n",
q*100, ssnext.format(), 10*log10f(m2));
#endif
// Estimate symbol rate (considered stable over whole frame)
float dist = (ssnext.p-ss.p) + (ssnext.mu-ss.mu);
// Set symbol period accordingly.
ss.omega = dist / (ns+sof.LENGTH);
}
// Pilots
int npilots = (S-1) / 16;
if (sspilots) {
delete[] sspilots;
}
sspilots = new sampler_state[npilots];
// Detect pilots
if (pls.pilots)
{
sampler_state ssp = ss;
for ( int i=0; i<npilots; ++i )
{
ssp.skip_symbols(16*PLSLOT_LENGTH);
interp_match_pilot(&ssp);
sspilots[i] = ssp;
#if DEBUG_LOOKAHEAD
fprintf(stderr, "LOOKAHEAD %d PILOT%02d sr %+3.0f %s %.1f dB\n",
plh_counter, i, (1-ssp.omega/omega0)*1e6,
ssp.format(), 10*log10f(mer2));
#endif
}
}
if (pls.pilots)
{
// Measure average frequency, using pilots to unwrap.
float totalph = 0;
float prevph = ss.ph16;
int span = 16*PLSLOT_LENGTH + pilot.LENGTH;
// Wrap phase around current freq estimate, pilot by pilot.
for (int i=0; i<npilots; ++i)
{
float dph = sspilots[i].ph16 - (prevph+ss.fw16*span);
totalph += fmodfs(dph, 65536.0f);
prevph = sspilots[i].ph16;
}
// TBD Use data between last pilot and next SOF ?
// Tricky when there is still an integer ambiguity.
ss.fw16 += totalph / (span*npilots);
}
else
{
// Measure average frequency over whole frame.
// Mostly useful for null frames.
int span = S*plslot<SOFTSYMB>::LENGTH + sof.LENGTH;
float dph = ssnext.ph16 - (ss.ph16+ss.fw16*span);
ss.fw16 += fmodfs(dph,65536.0f) / span;
}
#if DEBUG_LOOKAHEAD
fprintf(stderr, "LOOKAHEAD %d NEXTSOF sr %+3.0f %s %.1f dB\n",
plh_counter, (1-ssnext.omega/omega0)*1e6,
ssnext.format(), 10*log10f(mer2));
++plh_counter;
#endif
if (state == FRAME_PROBE)
{
float fw0 = ss.fw16;
match_frame(&ss, &pls, S, dcstln);
// Apply retroactively from midpoint of pilots and next SOF.
float fw_adj = ss.fw16 - fw0;
if (pls.pilots)
{
for (int i=0; i<npilots; ++i) {
sspilots[i].ph16 += fw_adj * PILOT_LENGTH / 2;
}
}
ssnext.ph16 += fw_adj * sof.LENGTH / 2;
#if DEBUG_CARRIER
fprintf(stderr, "CARRIER disambiguated: %s\n", ss.format());
#endif
}
// TBD In FRAME_LOCKED, match_frame with sliprange +-1
// to avoid broken locks ?
// Per-frame statistics on carrier frequency.
// Useful at very low symbol rates to detect situations where
// the carrier fluctuates too fast for pilot-aided recovery.
statistics<float> freq_stats;
// Read slots and pilots
#if DEBUG_CARRIER
fprintf(stderr, "CARRIER data: %s\n", ss.format());
#endif
// int pilot_errors = 0;
for (int slot=0; slot<S; ++slot,++pout)
{
// Pilot before this slot ?
if (pls.pilots && !(slot&15) && slot)
{
ss.skip_symbols(pilot.LENGTH);
ss.ph16 = sspilots[slot/16-1].ph16;
}
// Time for pilot-aided carrier recovery ?
if ( pls.pilots && !(slot&15) && slot+16<S )
{
// Sequence of data slots followed by pilots
sampler_state *ssp = &sspilots[slot/16];
int span = 16*pout->LENGTH + pilot.LENGTH;
float dph = ssp->ph16 - (ss.ph16+ss.fw16*span);
ss.fw16 += fmodfs(dph,65536.0f) / span;
}
else if (( pls.pilots && !(slot&15) && slot+16>=S) ||
(!pls.pilots && !slot ))
{
// Sequence of data slots followed by SOF
int span = (S-slot)*pout->LENGTH + sof.LENGTH;
float dph = ssnext.ph16 - (ss.ph16+ss.fw16*span);
ss.fw16 += fmodfs(dph,65536.0f) / span;
}
// Read slot.
freq_stats.add(ss.fw16);
pout->is_pls = false;
complex<float> p; // Export last symbols for cstln_out
for (int s=0; s<pout->LENGTH; ++s)
{
p = interp_next(&ss) * ss.gain;
#if TEST_DIVERSITY
if ( psymbols )
*psymbols++ = p * scale_symbols;
#endif
if (!pls.pilots || fastdrift) {
(void) track_symbol(&ss, p, dcstln); // SLOW
}
complex<float> d = descramble(&ss, p);
#if 1 // Slow
SOFTSYMB *symb = &dcstln->lookup(d.re, d.im)->ss;
#else // Avoid scaling floats. May wrap at very low SNR.
SOFTSYMB *symb = &dcstln->lookup((int)d.re, (int)d.im)->ss;
#endif
pout->symbols[s] = *symb;
}
ss.normalize();
if (psampled) {
*psampled++ = p;
}
} // slot
if (sch->debug2)
{
fprintf(
stderr,
"sr%+.0f fs=%.0f\n",
(1-ss.omega/omega0)*1e6,
(freq_stats.max()-freq_stats.min())*1e6/65536.0f
);
}
// Commit whole frame after final SOF.
if (! pls.is_dummy())
{
if ((modcods&(1<<pls.modcod)) && (framesizes&(1<<pls.sf)))
{
out.written(pout-pout0);
}
else
{
if (sch->debug2) {
fprintf(stderr, "modcod %d size %d rejected\n", pls.modcod, pls.sf);
}
}
}
// Write back sampler progress
meas_count += ss.p - in.rd();
in.read(ss.p-in.rd());
ss_cache = ss;
// Measurements
if (psampled) {
cstln_out->written(psampled-cstln_out->wr());
}
if (psampled_pls) {
cstln_pls_out->written(psampled_pls-cstln_pls_out->wr());
}
#if TEST_DIVERSITY
if ( psymbols ) symbols_out->written(psymbols-symbols_out->wr());
#endif
if (meas_count >= meas_decimation)
{
opt_write(freq_out, ss_cache.fw16/65536/ss_cache.omega);
opt_write(ss_out, cstln_amp / ss_cache.gain);
opt_write(mer_out, mer2 ? 10*log10f(mer2) : -99);
meas_count -= meas_decimation;
}
if (state == FRAME_PROBE)
{
// First frame completed successfully. Validate the lock.
enter_frame_locked();
}
if (ss_cache.fw16<min_freqw16 || ss_cache.fw16>max_freqw16)
{
if (sch->debug) {
fprintf(stderr, "Carrier out of bounds\n");
}
enter_frame_detect();
}
} // run_frame_probe_locked
// Find most likely PLHEADER between *pss and *pss+search_range
// by differential correlation.
// Align symbol timing.
// Estimate carrier frequency (to about +-10kppm).
// Estimate carrier phase (to about +-PI/4).
// Adjust *ss accordingly.
// Initialize AGC.
// Return confidence (unbounded, 0=bad, 1=nominal).
float find_plheader(sampler_state *pss, int search_range)
{
complex<T> best_corr = 0;
int best_imu = 0; // Avoid compiler warning.
int best_pos = 0; // Avoid compiler warning.
// Symbol clock is not recovered yet, so we try fractional symbols.
const int interp = 8;
for (int imu=0; imu<interp; ++imu)
{
const int ndiffs = search_range + sof.LENGTH + plscodes.LENGTH;
if (diffs) {
delete[] diffs;
}
diffs = new complex<T>[ndiffs];
sampler_state ss = *pss;
ss.mu += imu * ss.omega / interp;
// Compute rotation between consecutive symbols.
complex<T> prev = 0;
for (int i=0; i<ndiffs; ++i)
{
complex<T> p = interp_next(&ss);
diffs[i] = conjprod(prev, p);
prev = p;
}
// Find best PLHEADER candidate position.
const int ncorrs = search_range;
for (int i=0; i<ncorrs; ++i)
{
complex<T> c = correlate_plheader_diff(&diffs[i]);
//if ( cnorm2(c) > cnorm2(best_corr) ) {
// c.im>0 enforces frequency error +-Fm/4
if (cnorm2(c)>cnorm2(best_corr) && c.im>0)
{
best_corr = c;
best_imu = imu;
best_pos = i;
}
}
} // imu
// Setup sampler according to best match.
pss->mu += best_imu * pss->omega / interp;
pss->skip_symbols(best_pos);
pss->normalize();
#if 0
// Lowpass-filter the differential correlator.
// (Does not help much.)
static complex<float> acc = 0;
static const float k = 0.05;
acc = best_corr*k + acc*(1-k);
best_corr = acc;
#endif
// Get rough estimate of carrier frequency from differential correlator.
// (best_corr is nominally +j).
float freqw = atan2f(-best_corr.re, best_corr.im);
pss->fw16 += freqw * 65536 / (2*M_PI);
// Force refresh because correction may be large.
sampler->update_freq(pss->fw16/omega0);
// Interpolate SOF with initial frequency estimation.
// Estimate phase by correlation.
// Initialize AGC (naive).
float q;
{
sampler_state ss = *pss;
float power = 0;
complex<T> symbs[sof.LENGTH];
for (int i=0; i<sof.LENGTH; ++i)
{
symbs[i] = interp_next(&ss);
power += cnorm2(symbs[i]);
}
complex<float> c = conjprod(sof.symbols, symbs, sof.LENGTH);
c *= 1.0f / sof.LENGTH;
align_phase(pss, c);
float signal_amp = sqrtf(power/sof.LENGTH);
q = sqrtf(cnorm2(c)) / (cstln_amp*signal_amp);
pss->gain = cstln_amp / signal_amp;
}
return q;
}
// Correlate PLHEADER.
complex<float> correlate_plheader_diff(complex<T> *diffs)
{
complex<T> csof = correlate_sof_diff(diffs);
complex<T> cplsc = correlate_plscode_diff(&diffs[sof.LENGTH]);
// Use csof+cplsc or csof-cplsc, whichever maximizes likelihood.
complex<T> c0 = csof + cplsc; // Best when b7==0 (pilots off)
complex<T> c1 = csof - cplsc; // Best when b7==1 (pilots on)
complex<T> c = (cnorm2(c0)>cnorm2(c1)) ? c0 : c1;
return c * (1.0f/(26-1+64/2));
}
// Correlate 25 differential transitions in SOF.
complex<float> correlate_sof_diff(complex<T> *diffs)
{
complex<T> c = 0;
const uint32_t dsof = sof.VALUE ^ (sof.VALUE>>1);
for (int i=0; i<sof.LENGTH; ++i)
{
// Constant odd bit => +PI/4
// Constant even bit => -PI/4
// Toggled odd bit => -PI/4
// Toggled even bit => +PI/4
if (((dsof>>(sof.LENGTH-1-i)) ^ i) & 1) {
c += diffs[i];
} else {
c -= diffs[i];
}
}
return c;
}
// Correlate 32 data-independent transitions in PLSCODE.
complex<float> correlate_plscode_diff(complex<T> *diffs)
{
complex<T> c = 0;
uint64_t dscr = plscodes.SCRAMBLING ^ (plscodes.SCRAMBLING>>1);
for (int i=1; i<plscodes.LENGTH; i+=2)
{
if ( (dscr>>(plscodes.LENGTH-1-i)) & 1 ) {
c -= diffs[i];
} else {
c += diffs[i];
}
}
return c;
}
// Adjust carrier frequency in *pss to match target phase after ns symbols.
void adjust_freq(sampler_state *pss, int ns, const sampler_state *pnext)
{
// Note: Minimum deviation from current estimate.
float adj = fmodfs(pnext->ph16-(pss->ph16+pss->fw16*ns),65536.0f) / ns;
// 2sps vcm avec adj 10711K
// 2sps vcm avec adj/2 10265k
// 2sps vcm sans adj 8060K
// 5sps 2MS1 avec adj 2262K
// 5sps 2MS1 avec adj/2 3109K
// 5sps 2MS1 avec adj/3 3254K
// 5sps 2MS1 sans adj 3254K
// 1.2sps oldbeacon avec adj 5774K
// 1.2sps oldbeacon avec adj/2 15M
// 1.2sps oldbeacon avec adj/3 15.6M max 17M
// 1.2sps oldbeacon sans adj 14M malgré drift
pss->fw16 += adj;
}
// Estimate frequency from known symbols by differential correlation.
// Adjust *ss accordingly.
// Retroactively frequency-shift the samples in-place.
//
// *ss must point after the sampled symbols.
// expect[] must be PSK with amplitude cstln_amp.
// Idempotent.
// Not affected by phase error nor by gain mismatch.
// Can handle +-25% error.
// Result is typically such that residual phase error over a PLHEADER
// spans less than 90°.
void match_freq(
complex<float> *expect,
complex<float> *recv,
int ns,
sampler_state *ss)
{
complex<float> diff = 0;
for (int i=0; i<ns-1; ++i)
{
complex<float> de = conjprod(expect[i], expect[i+1]);
complex<float> dr = conjprod(recv[i], recv[i+1]);
diff += conjprod(de, dr);
}
float dfw16 = atan2f(diff.im,diff.re) * 65536 / (2*M_PI);
// Derotate.
for (int i=0; i<ns; ++i) {
recv[i] *= trig.expi(-dfw16*i);
}
ss->fw16 += dfw16;
ss->ph16 += dfw16 * ns; // Retroactively
}
// Interpolate a pilot block.
// Perform ML match.
float interp_match_pilot(sampler_state *pss)
{
complex<T> symbols[pilot.LENGTH];
complex<T> expected[pilot.LENGTH];
for (int i=0; i<pilot.LENGTH; ++i)
{
complex<float> p = interp_next(pss) * pss->gain;
symbols[i] = descramble(pss, p);
expected[i] = pilot.symbol;
//fprintf(stderr, "%f %f\n", symbols[i].re, symbols[i].im);
}
return match_ph_amp(expected, symbols, pilot.LENGTH, pss);
}
// Interpolate a SOF.
// Perform ML match.
float interp_match_sof(sampler_state *pss)
{
complex<T> symbols[pilot.LENGTH];
for (int i=0; i<sof.LENGTH; ++i) {
symbols[i] = interp_next(pss) * pss->gain;
}
return match_ph_amp(sof.symbols, symbols, sof.LENGTH, pss);
}
// Estimate phase and amplitude from known symbols.
// Adjust *ss accordingly.
// Retroactively derotate and scale the samples in-place.
// Return MER^2.
//
// *ss must point after the sampled symbols, with gain applied.
// expect[] must be PSK (not APSK) with amplitude cstln_amp.
// Idempotent.
float match_ph_amp(
complex<float> *expect,
complex<float> *recv,
int ns,
sampler_state *ss
)
{
complex<float> rr = 0;
for (int i=0; i<ns; ++i) {
rr += conjprod(expect[i], recv[i]);
}
rr *= 1.0f / (ns*cstln_amp);
float dph16 = atan2f(rr.im,rr.re) * 65536 / (2*M_PI);
ss->ph16 += dph16;
rr *= trig.expi(-dph16);
// rr.re is now the modulation amplitude.
float dgain = cstln_amp / rr.re;
ss->gain *= dgain;
// Rotate and scale. Compute error power.
complex<float> adj = trig.expi(-dph16) * dgain;
float ev2 = 0;
for (int i=0; i<ns; ++i)
{
recv[i] *= adj;
ev2 += cnorm2(recv[i]-expect[i]);
}
// Return MER^2.
ev2 *= 1.0f / (ns*cstln_amp*cstln_amp);
return 1.0f / ev2;
}
// Adjust frequency in *pss by an integer number of cycles per data block
// so that phases align best on data symbols.
//
// *pss must point to the beginning of a frame.
void match_frame(
sampler_state *pss,
const s2_pls *pls,
int S,
cstln_lut<SOFTSYMB,256> *dcstln
)
{
// With pilots: Use first block of data slots.
// Without pilots: Use whole frame.
int ns = pls->pilots ? 16*90 : S*90;
// Pilots: steps of ~700 ppm (= 1 cycle between pilots)
// No pilots, normal frames: steps of ~30(QPSK) - ~80(32APSK) ppm
// No pilots, short frames: steps of ~120(QPSK) - 300(32APSK) ppm
int nwrap = pls->pilots ? 16*90+pilot.LENGTH : S*90+sof.LENGTH;
// Frequency search range.
int sliprange = pls->pilots ? 10 : 50; // TBD Customizable ?
float besterr = 1e99;
float bestslip = 0; // Avoid compiler warning
for (int slip=-sliprange; slip<=sliprange; ++slip)
{
sampler_state ssl = *pss;
float dfw = slip * 65536.0f / nwrap;
ssl.fw16 += dfw;
// Apply retroactively from midpoint of preceeding PLHEADER,
// where the phase from match_ph_amp is most reliable.
ssl.ph16 += dfw * (plscodes.LENGTH+sof.LENGTH)/2;
float err = 0;
for (int s=0; s<ns; ++s)
{
complex<float> p = interp_next(&ssl) * ssl.gain;
typename cstln_lut<SOFTSYMB,256>::result *cr =
dcstln->lookup(p.re, p.im);
complex<int8_t> &cp = dcstln->symbols[cr->symbol];
complex<float> ev(p.re-cp.re, p.im-cp.im);
err += cnorm2(ev);
}
err /= ns * cstln_amp * cstln_amp;
if (err < besterr)
{
besterr=err;
bestslip=slip;
}
#if DEBUG_CARRIER
fprintf(stderr, "slip %+3d %6.0f ppm err=%f\n",
slip, ssl.fw16*1e6/65536, err);
#endif
}
pss->fw16 += bestslip * 65536.0f / nwrap;
} // match_frame
void shutdown()
{
if (sch->verbose)
{
fprintf(
stderr,
"PL errors: %d/%d (%.0f ppm)\n",
pls_total_errors,
pls_total_count,
1e6 * pls_total_errors / pls_total_count
);
}
}
complex<float> descramble(sampler_state *ss, const complex<float> &p)
{
int r = *ss->scr++;
complex<float> res;
switch (r)
{
case 3:
res.re = -p.im;
res.im = p.re;
break;
case 2:
res.re = -p.re;
res.im = -p.im;
break;
case 1:
res.re = p.im;
res.im = -p.re;
break;
default:
res = p;
}
return res;
}
// Interpolator
inline complex<float> interp_next(sampler_state *ss)
{
// Skip to next sample
while (ss->mu >= 1)
{
++ss->p;
ss->mu-=1.0f;
}
// Interpolate
#if 0
// Interpolate linearly then derotate.
// This will fail with large carrier offsets (e.g. --tune).
float cmu = 1.0f - ss->mu;
complex<float> s(ss->p[0].re*cmu + ss->p[1].re*ss->mu,
ss->p[0].im*cmu + ss->p[1].im*ss->mu);
ss->mu += ss->omega;
// Derotate
const complex<float> &rot = trig.expi(-ss->ph16);
ss->ph16 += ss->fw16;
return rot * s;
#else
// Use generic interpolator
complex<float> s = sampler->interp(ss->p, ss->mu, ss->ph16);
ss->mu += ss->omega;
ss->ph16 += ss->fw16;
return s;
#endif
}
// Adjust phase in [ss] to cancel offset observed as [c].
void align_phase(sampler_state *ss, const complex<float> &c)
{
float err = atan2f(c.im,c.re) * 65536 / (2*M_PI);
ss->ph16 += err;
}
inline uint8_t track_symbol(
sampler_state *ss,
const complex<float> &p,
cstln_lut<SOFTSYMB,256> *c
)
{
static const float kph = 4e-2;
static const float kfw = 1e-4;
// Decision
typename cstln_lut<SOFTSYMB,256>::result *cr = c->lookup(p.re, p.im);
// Carrier tracking
ss->ph16 += cr->phase_error * kph;
ss->fw16 += cr->phase_error * kfw;
if (ss->fw16 < min_freqw16) {
ss->fw16 = min_freqw16;
}
if (ss->fw16 > max_freqw16) {
ss->fw16 = max_freqw16;
}
return cr->symbol;
}
public:
cstln_lut<SOFTSYMB,256> *qpsk;
s2_plscodes<T> plscodes;
cstln_lut<SOFTSYMB,256> *cstlns[32]; // Constellations in use, by modcod
cstln_lut<SOFTSYMB,256> *get_cstln(int modcod)
{
if (!cstlns[modcod])
{
const modcod_info *mcinfo = &modcod_infos[modcod];
if (sch->debug)
{
fprintf(
stderr,
"Creating LUT for %s ratecode %d\n",
cstln_base::names[mcinfo->c],
mcinfo->rate
);
}
cstlns[modcod] = new cstln_lut<SOFTSYMB,256>(
mcinfo->c,
mcinfo->esn0_nf,
mcinfo->g1,
mcinfo->g2,
mcinfo->g3
);
#if 0
fprintf(stderr, "Dumping constellation LUT to stdout.\n");
cstlns[modcod]->dump(stdout);
exit(0);
#endif
}
return cstlns[modcod];
}
cstln_lut<SOFTSYMB,256> *cstln; // Last seen, or NULL (legacy)
trig16 trig;
pipereader< complex<T> > in;
pipewriter< plslot<SOFTSYMB> > out;
int meas_count;
pipewriter<float> *freq_out, *ss_out, *mer_out;
pipewriter< complex<float> > *cstln_out;
pipewriter< complex<float> > *cstln_pls_out;
pipewriter< complex<float> > *symbols_out;
pipewriter<int> *state_out;
bool first_run;
// S2 constants
s2_scrambling scrambling;
s2_sof<T> sof;
s2_pilot<T> pilot;
// Performance stats on PL signalling
uint32_t pls_total_errors, pls_total_count;
int m_modcodType;
int m_modcodRate;
private:
complex<T> *diffs;
sampler_state *sspilots;
}; // s2_frame_receiver
template <typename SOFTBYTE>
struct fecframe
{
s2_pls pls;
SOFTBYTE bytes[64800 / 8]; // Contains 16200/8 or 64800/8 bytes.
};
// S2 INTERLEAVER
// EN 302 307-1 section 5.3.3 Bit Interleaver
struct s2_interleaver : runnable
{
s2_interleaver(
scheduler *sch,
pipebuf<fecframe<hard_sb>> &_in,
pipebuf<plslot<hard_ss>> &_out
) :
runnable(sch, "S2 interleaver"),
in(_in),
out(_out, 1 + 360)
{
}
void run()
{
while (in.readable() >= 1)
{
const s2_pls *pls = &in.rd()->pls;
const modcod_info *mcinfo = check_modcod(pls->modcod);
int nslots = pls->sf ? mcinfo->nslots_nf / 4 : mcinfo->nslots_nf;
if (out.writable() < 1 + nslots) {
return;
}
const hard_sb *pbytes = in.rd()->bytes;
// Output pseudo slot with PLS.
plslot<hard_ss> *ppls = out.wr();
ppls->is_pls = true;
ppls->pls = *pls;
out.written(1);
// Interleave
plslot<hard_ss> *pout = out.wr();
if (mcinfo->nsymbols == 4)
{
serialize_qpsk(pbytes, nslots, pout);
}
else
{
int bps = log2(mcinfo->nsymbols);
int rows = pls->framebits() / bps;
if (mcinfo->nsymbols == 8 && mcinfo->rate == FEC35) {
interleave(bps, rows, pbytes, nslots, false, pout);
} else {
interleave(bps, rows, pbytes, nslots, true, pout);
}
}
in.read(1);
out.written(nslots);
}
}
private:
// Fill slots with serialized QPSK symbols, MSB first.
static void serialize_qpsk(const hard_sb *pin, int nslots,
plslot<hard_ss> *pout)
{
#if 0 // For reference
hard_sb acc;
int nacc = 0;
for ( ; nslots; --nslots,++pout ) {
pout->is_pls = false;
hard_ss *ps = pout->symbols;
for ( int ns=pout->LENGTH; ns--; ++ps ) {
if ( nacc < 2 ) { acc=*pin++; nacc=8; }
*ps = acc>>6;
acc <<= 2;
nacc -= 2;
}
}
if ( nacc ) fail("Bug: s2_interleaver");
#else
if (nslots % 2) {
fatal("Bug: Truncated byte");
}
for (; nslots; nslots -= 2)
{
hard_sb b;
hard_ss *ps;
// Slot 0 (mod 2)
pout->is_pls = false;
ps = pout->symbols;
for (int i = 0; i < 22; ++i)
{
b = *pin++;
*ps++ = (b >> 6);
*ps++ = (b >> 4) & 3;
*ps++ = (b >> 2) & 3;
*ps++ = (b)&3;
}
b = *pin++;
*ps++ = (b >> 6);
*ps++ = (b >> 4) & 3;
// Slot 1 (mod 2)
++pout;
pout->is_pls = false;
ps = pout->symbols;
*ps++ = (b >> 2) & 3;
*ps++ = (b)&3;
for (int i = 0; i < 22; ++i)
{
b = *pin++;
*ps++ = (b >> 6);
*ps++ = (b >> 4) & 3;
*ps++ = (b >> 2) & 3;
*ps++ = (b)&3;
}
++pout;
}
#endif
}
// Fill slots with interleaved symbols.
// EN 302 307-1 figures 7 and 8
#if 0 // For reference
static void interleave(int bps, int rows,
const hard_sb *pin, int nslots,
bool msb_first, plslot<hard_ss> *pout) {
if ( bps==4 && rows==4050 && msb_first )
return interleave4050(pin, nslots, pout);
if ( rows % 8 ) fatal("modcod/framesize combination not supported\n");
int stride = rows/8; // Offset to next column, in bytes
hard_sb accs[bps]; // One accumulator per column
int nacc = 0; // Bits in each column accumulator
for ( ; nslots; --nslots,++pout ) {
pout->is_pls = false;
hard_ss *ps = pout->symbols;
for ( int ns=pout->LENGTH; ns--; ++ps ) {
if ( ! nacc ) {
const hard_sb *pi = pin;
for ( int b=0; b<bps; ++b,pi+=stride ) accs[b] = *pi;
++pin;
nacc = 8;
}
hard_ss symb = 0;
if ( msb_first )
for ( int b=0; b<bps; ++b ) {
symb = (symb<<1) | (accs[b]>>7);
accs[b] <<= 1;
}
else
for ( int b=bps; b--; ) {
symb = (symb<<1) | (accs[b]>>7);
accs[b] <<= 1;
}
--nacc;
*ps = symb;
}
}
if ( nacc ) fail("Bug: s2_interleaver");
}
#else // reference
static void interleave(int bps, int rows,
const hard_sb *pin, int nslots,
bool msb_first, plslot<hard_ss> *pout)
{
void (*func)(int rows, const hard_sb *pin, int nslots,
plslot<hard_ss> *pout) = 0;
if (msb_first)
{
switch (bps)
{
case 2:
func = interleave<1, 2>;
break;
case 3:
func = interleave<1, 3>;
break;
case 4:
func = interleave<1, 4>;
break;
case 5:
func = interleave<1, 5>;
break;
default:
fail("Bad bps");
}
}
else
{
switch (bps)
{
case 2:
func = interleave<0, 2>;
break;
case 3:
func = interleave<0, 3>;
break;
case 4:
func = interleave<0, 4>;
break;
case 5:
func = interleave<0, 5>;
break;
default:
fail("Bad bps");
}
}
(*func)(rows, pin, nslots, pout);
}
template <int MSB_FIRST, int BPS>
static void interleave(int rows, const hard_sb *pin, int nslots,
plslot<hard_ss> *pout)
{
if (BPS == 4 && rows == 4050 && MSB_FIRST) {
return interleave4050(pin, nslots, pout);
}
if (rows % 8) {
fatal("modcod/framesize combination not supported\n");
}
int stride = rows / 8; // Offset to next column, in bytes
if (nslots % 4) {
fatal("Bug: Truncated byte");
}
// plslot::symbols[] are not packed across slots,
// so we need tos split bytes at boundaries.
for (; nslots; nslots -= 4)
{
hard_sb accs[BPS]; // One accumulator per column
hard_ss *ps;
// Slot 0 (mod 4): 88+2
pout->is_pls = false;
ps = pout->symbols;
for (int i = 0; i < 11; ++i)
{
split_byte<BPS>(pin++, stride, accs);
pop_symbols<MSB_FIRST, BPS>(accs, &ps, 8);
}
split_byte<BPS>(pin++, stride, accs);
pop_symbols<MSB_FIRST, BPS>(accs, &ps, 2);
++pout;
// Slot 1 (mod 4): 6+80+4
pout->is_pls = false;
ps = pout->symbols;
pop_symbols<MSB_FIRST, BPS>(accs, &ps, 6);
for (int i = 0; i < 10; ++i)
{
split_byte<BPS>(pin++, stride, accs);
pop_symbols<MSB_FIRST, BPS>(accs, &ps, 8);
}
split_byte<BPS>(pin++, stride, accs);
pop_symbols<MSB_FIRST, BPS>(accs, &ps, 4);
++pout;
// Slot 2 (mod 4): 4+80+6
pout->is_pls = false;
ps = pout->symbols;
pop_symbols<MSB_FIRST, BPS>(accs, &ps, 4);
for (int i = 0; i < 10; ++i)
{
split_byte<BPS>(pin++, stride, accs);
pop_symbols<MSB_FIRST, BPS>(accs, &ps, 8);
}
split_byte<BPS>(pin++, stride, accs);
pop_symbols<MSB_FIRST, BPS>(accs, &ps, 6);
++pout;
// Slot 3 (mod 4): 2+88
pout->is_pls = false;
ps = pout->symbols;
pop_symbols<MSB_FIRST, BPS>(accs, &ps, 2);
for (int i = 0; i < 11; ++i)
{
split_byte<BPS>(pin++, stride, accs);
pop_symbols<MSB_FIRST, BPS>(accs, &ps, 8);
}
++pout;
}
}
template <int BPS>
static inline void split_byte(const hard_sb *pi, int stride,
hard_sb accs[BPS])
{
// TBD Pass stride as template parameter.
for (int b = 0; b < BPS; ++b, pi += stride) {
accs[b] = *pi;
}
}
template <int MSB_FIRST, int BPS>
static void pop_symbols(hard_sb accs[BPS], hard_ss **ps, int ns)
{
for (int i = 0; i < ns; ++i)
{
hard_ss symb = 0;
// Check unrolling and constant propagation.
for (int b = 0; b < BPS; ++b)
{
if (MSB_FIRST) {
symb = (symb << 1) | (accs[b] >> 7);
} else {
symb = (symb << 1) | (accs[BPS - 1 - b] >> 7);
}
}
for (int b = 0; b < BPS; ++b) {
accs[b] <<= 1;
}
*(*ps)++ = symb;
}
}
#endif // reference
// Special case for 16APSK short frames.
// 4050 rows is not a multiple of 8.
static void interleave4050(const hard_sb *pin, int nslots,
plslot<hard_ss> *pout)
{
hard_sb accs[4]; // One accumulator per column
int nacc = 0; // Bits in each column accumulator
for (; nslots; --nslots, ++pout)
{
pout->is_pls = false;
hard_ss *ps = pout->symbols;
for (int ns = pout->LENGTH; ns--; ++ps)
{
if (!nacc)
{
if (nslots == 1 && ns == 1)
{
// Special case just to avoid reading beyond end of buffer
accs[0] = pin[0];
accs[1] = (pin[506] << 2) | (pin[507] >> 6);
accs[2] = (pin[1012] << 4) | (pin[1013] >> 4);
accs[3] = (pin[1518] << 6);
}
else
{
accs[0] = pin[0];
accs[1] = (pin[506] << 2) | (pin[507] >> 6);
accs[2] = (pin[1012] << 4) | (pin[1013] >> 4);
accs[3] = (pin[1518] << 6) | (pin[1519] >> 2);
}
++pin;
nacc = 8;
}
hard_ss symb = 0;
for (int b = 0; b < 4; ++b)
{
symb = (symb << 1) | (accs[b] >> 7);
accs[b] <<= 1;
}
--nacc;
*ps = symb;
}
}
}
pipereader<fecframe<hard_sb>> in;
pipewriter<plslot<hard_ss>> out;
}; // s2_interleaver
// S2 DEINTERLEAVER
// EN 302 307-1 section 5.3.3 Bit Interleaver
template <typename SOFTSYMB, typename SOFTBYTE>
struct s2_deinterleaver : runnable
{
s2_deinterleaver(
scheduler *sch,
pipebuf<plslot<SOFTSYMB>> &_in,
pipebuf<fecframe<SOFTBYTE>> &_out
) :
runnable(sch, "S2 deinterleaver"),
in(_in),
out(_out)
{
}
void run()
{
while (in.readable() >= 1 && out.writable() >= 1)
{
plslot<SOFTSYMB> *pin = in.rd();
if (!pin->is_pls) {
fail("s2_deinterleaver: bad input sequence");
}
s2_pls *pls = &pin->pls;
const modcod_info *mcinfo = check_modcod(pls->modcod);
int nslots = pls->sf ? mcinfo->nslots_nf / 4 : mcinfo->nslots_nf;
if (in.readable() < 1 + nslots) {
return;
}
fecframe<SOFTBYTE> *pout = out.wr();
pout->pls = *pls;
SOFTBYTE *pbytes = pout->bytes;
if (mcinfo->nsymbols == 4)
{
deserialize_qpsk(pin + 1, nslots, pbytes);
}
else
{
int bps = log2(mcinfo->nsymbols);
int rows = pls->framebits() / bps;
if ((mcinfo->nsymbols == 8) && (mcinfo->rate == FEC35)) {
deinterleave(bps, rows, pin + 1, nslots, false, pbytes);
} else {
deinterleave(bps, rows, pin + 1, nslots, true, pbytes);
}
}
in.read(1 + nslots);
out.written(1);
}
}
private:
// Deserialize slots of QPSK symbols, MSB first.
static void deserialize_qpsk(plslot<SOFTSYMB> *pin, int nslots,
SOFTBYTE *pout)
{
SOFTBYTE acc;
softword_clear(&acc); // gcc warning
int nacc = 0;
for (; nslots; --nslots, ++pin)
{
SOFTSYMB *ps = pin->symbols;
for (int ns = pin->LENGTH; ns--; ++ps)
{
pack_qpsk_symbol(*ps, &acc, nacc);
nacc += 2;
if (nacc == 8)
{ // TBD unroll
*pout++ = acc;
nacc = 0;
}
}
}
}
// Deinterleave slots of symbols.
// EN 302 307-1 figures 7 and 8
#if 0 // For reference
static void deinterleave(int bps, int rows,
const plslot<SOFTSYMB> *pin, int nslots,
bool msb_first, SOFTBYTE *pout) {
if ( bps==4 && rows==4050 && msb_first )
return deinterleave4050(pin, nslots, pout);
if ( rows % 8 ) fatal("modcod/framesize combination not supported\n");
int stride = rows/8; // Offset to next column, in bytes
SOFTBYTE accs[bps];
for ( int b=0; b<bps; ++b ) softword_clear(&accs[b]); // gcc warning
int nacc = 0;
for ( ; nslots; --nslots,++pin ) {
const SOFTSYMB *ps = pin->symbols;
for ( int ns=pin->LENGTH; ns--; ++ps ) {
split_symbol(*ps, bps, accs, nacc, msb_first);
++nacc;
if ( nacc == 8 ) {
SOFTBYTE *po = pout;
for ( int b=0; b<bps; ++b,po+=stride ) *po = accs[b];
++pout;
nacc = 0;
}
}
}
if ( nacc ) fail("Bug: s2_deinterleaver");
}
#else // reference
static void deinterleave(int bps, int rows,
const plslot<SOFTSYMB> *pin, int nslots,
bool msb_first, SOFTBYTE *pout)
{
void (*func)(int rows, const plslot<SOFTSYMB> *pin, int nslots,
SOFTBYTE *pout) = 0;
if (msb_first)
{
switch (bps)
{
case 2:
func = deinterleave<1, 2>;
break;
case 3:
func = deinterleave<1, 3>;
break;
case 4:
func = deinterleave<1, 4>;
break;
case 5:
func = deinterleave<1, 5>;
break;
default:
fail("Bad bps");
}
}
else
{
switch (bps)
{
case 2:
func = deinterleave<0, 2>;
break;
case 3:
func = deinterleave<0, 3>;
break;
case 4:
func = deinterleave<0, 4>;
break;
case 5:
func = deinterleave<0, 5>;
break;
default:
fail("Bad bps");
}
}
(*func)(rows, pin, nslots, pout);
}
template <int MSB_FIRST, int BPS>
static void deinterleave(int rows, const plslot<SOFTSYMB> *pin, int nslots,
SOFTBYTE *pout)
{
if (BPS == 4 && rows == 4050 && MSB_FIRST) {
return deinterleave4050(pin, nslots, pout);
}
if (rows % 8) {
fatal("modcod/framesize combination not supported\n");
}
int stride = rows / 8; // Offset to next column, in bytes
SOFTBYTE accs[BPS];
for (int b = 0; b < BPS; ++b) {
softword_clear(&accs[b]); // gcc warning
}
int nacc = 0;
for (; nslots; --nslots, ++pin)
{
const SOFTSYMB *ps = pin->symbols;
for (int ns = pin->LENGTH; ns--; ++ps)
{
split_symbol(*ps, BPS, accs, nacc, MSB_FIRST);
++nacc;
if (nacc == 8)
{ // TBD Unroll, same as interleave()
SOFTBYTE *po = pout;
// TBD Pass stride as template parameter.
for (int b = 0; b < BPS; ++b, po += stride) {
*po = accs[b];
}
++pout;
nacc = 0;
}
}
}
if (nacc) {
fail("Bug: s2_deinterleaver");
}
}
#endif // reference
// Special case for 16APSK short frames.
// 4050 rows is not a multiple of 8
// so we process rows one at a time rather than in chunks of 8.
static void deinterleave4050(const plslot<SOFTSYMB> *pin, int nslots,
SOFTBYTE *pout)
{
const int rows = 4050;
SOFTBYTE accs[4];
for (int b = 0; b < 4; ++b) {
softword_clear(&accs[b]); // gcc warning
}
int nacc = 0;
for (; nslots; --nslots, ++pin)
{
const SOFTSYMB *ps = pin->symbols;
for (int ns = pin->LENGTH; ns--; ++ps)
{
split_symbol(*ps, 4, accs, nacc, true);
++nacc;
if (nacc == 8)
{
for (int b = 0; b < 8; ++b)
{
softwords_set(pout, rows * 0 + b, softword_get(accs[0], b));
softwords_set(pout, rows * 1 + b, softword_get(accs[1], b));
softwords_set(pout, rows * 2 + b, softword_get(accs[2], b));
softwords_set(pout, rows * 3 + b, softword_get(accs[3], b));
}
++pout;
nacc = 0;
}
}
}
if (nacc != 2) {
fatal("Bug: Expected 2 leftover rows\n");
}
// Pad with random symbol so that we can use accs[].
for (int b = nacc; b < 8; ++b) {
split_symbol(pin->symbols[0], 4, accs, b, true);
}
for (int b = 0; b < nacc; ++b)
{
softwords_set(pout, rows * 0 + b, softword_get(accs[0], b));
softwords_set(pout, rows * 1 + b, softword_get(accs[1], b));
softwords_set(pout, rows * 2 + b, softword_get(accs[2], b));
softwords_set(pout, rows * 3 + b, softword_get(accs[3], b));
}
}
// Spread LLR symbol across hard columns.
// Must call 8 times before using result because we use bit shifts.
static inline void split_symbol(const llr_ss &ps, int bps,
hard_sb accs[/*bps*/], int nacc,
bool msb_first)
{
(void) nacc;
if (msb_first)
{
for (int b = 0; b < bps; ++b) {
accs[b] = (accs[b] << 1) | llr_harden(ps.bits[bps - 1 - b]);
}
}
else
{
for (int b = 0; b < bps; ++b) {
accs[b] = (accs[b] << 1) | llr_harden(ps.bits[b]);
}
}
}
// Fast variant
template <int MSB_FIRST, int BPS>
static inline void split_symbol(const llr_ss &ps,
hard_sb accs[/*bps*/], int nacc)
{
if (MSB_FIRST)
{
for (int b = 0; b < BPS; ++b) {
accs[b] = (accs[b] << 1) | llr_harden(ps.bits[BPS - 1 - b]);
}
}
else
{
for (int b = 0; b < BPS; ++b) {
accs[b] = (accs[b] << 1) | llr_harden(ps.bits[b]);
}
}
}
// Spread LLR symbol across LLR columns.
static inline void split_symbol(
const llr_ss &ps,
int bps,
llr_sb accs[/*bps*/],
int nacc,
bool msb_first
)
{
if (msb_first)
{
for (int b = 0; b < bps; ++b) {
accs[b].bits[nacc] = ps.bits[bps - 1 - b];
}
}
else
{
for (int b = 0; b < bps; ++b) {
accs[b].bits[nacc] = ps.bits[b];
}
}
}
// Fast variant
template <int MSB_FIRST, int BPS>
static inline void split_symbol(
const llr_ss &ps,
llr_sb accs[/*bps*/],
int nacc)
{
if (MSB_FIRST)
{
for (int b = 0; b < BPS; ++b) {
accs[b].bits[nacc] = ps.bits[BPS - 1 - b];
}
}
else
{
for (int b = 0; b < BPS; ++b) {
accs[b].bits[nacc] = ps.bits[b];
}
}
}
// Merge QPSK LLR symbol into hard byte.
static inline void pack_qpsk_symbol(
const llr_ss &ps,
hard_sb *acc,
int nacc
)
{
(void) nacc;
// TBD Must match LLR law, see softsymb_harden.
uint8_t s = llr_harden(ps.bits[0]) | (llr_harden(ps.bits[1]) << 1);
*acc = (*acc << 2) | s;
}
// Merge QPSK LLR symbol into LLR byte.
static inline void pack_qpsk_symbol(
const llr_ss &ps,
llr_sb *acc,
int nacc
)
{
acc->bits[nacc] = ps.bits[1];
acc->bits[nacc + 1] = ps.bits[0];
}
pipereader<plslot<SOFTSYMB>> in;
pipewriter<fecframe<SOFTBYTE>> out;
}; // s2_deinterleaver
typedef ldpc_table<uint16_t> s2_ldpc_table;
typedef ldpc_engine<bool, hard_sb, 8, uint16_t> s2_ldpc_engine;
#include "dvbs2_data.h"
static const struct fec_info
{
static const int KBCH_MAX = 58192;
int Kbch; // BCH message size (bits)
int kldpc; // LDPC message size (= BCH codeword size) (bits)
int t; // BCH error correction
const s2_ldpc_table *ldpc;
}
fec_infos[2][FEC_COUNT] =
{
{
// Normal frames - must respect enum code_rate order
{32208, 32400, 12, &ldpc_nf_fec12}, // FEC12 (was [FEC12] = {...} and so on. Does not compile with MSVC)
{43040, 43200, 10, &ldpc_nf_fec23}, // FEC23
{0, 0, 0, nullptr}, // FEC46
{48408, 48600, 12, &ldpc_nf_fec34}, // FEC34
{53840, 54000, 10, &ldpc_nf_fec56}, // FEC56
{0, 0, 0, nullptr}, // FEC78
{51648, 51840, 12, &ldpc_nf_fec45}, // FEC45
{57472, 57600, 8, &ldpc_nf_fec89}, // FEC89
{58192, 58320, 8, &ldpc_nf_fec910}, // FEC910
{16008, 16200, 12, &ldpc_nf_fec14}, // FEC14
{21408, 21600, 12, &ldpc_nf_fec13}, // FEC13
{25728, 25920, 12, &ldpc_nf_fec25}, // FEC25
{38688, 38880, 12, &ldpc_nf_fec35}, // FEC35
},
{
// Short frames - must respect enum code_rate order
{7032, 7200, 12, &ldpc_sf_fec12}, // FEC12 (was [FEC12] = {...} and so on. Does not compile with MSVC)
{10632, 10800, 12, &ldpc_sf_fec23}, // FEC23
{0, 0, 0, nullptr}, // FEC46
{11712, 11880, 12, &ldpc_sf_fec34}, // FEC34
{13152, 13320, 12, &ldpc_sf_fec56}, // FEC56
{0, 0, 0, nullptr}, // FEC78
{12432, 12600, 12, &ldpc_sf_fec45}, // FEC45
{14232, 14400, 12, &ldpc_sf_fec89}, // FEC89
{0, 0, 0, nullptr}, // FEC910
{3072, 3240, 12, &ldpc_sf_fec14}, // FEC14
{5232, 5400, 12, &ldpc_sf_fec13}, // FEC13
{6312, 6480, 12, &ldpc_sf_fec25}, // FEC25
{9552, 9720, 12, &ldpc_sf_fec35}, // FEC35
},
};
struct bbframe
{
s2_pls pls;
uint8_t bytes[58192 / 8]; // Kbch/8 max
};
// S2_LDPC_ENGINES
// Initializes LDPC engines for all DVB-S2 FEC settings.
template <typename SOFTBIT, typename SOFTBYTE>
struct s2_ldpc_engines
{
typedef ldpc_engine<SOFTBIT, SOFTBYTE, 8, uint16_t> s2_ldpc_engine;
s2_ldpc_engine *ldpcs[2][FEC_COUNT]; // [shortframes][fec]
s2_ldpc_engines()
{
// memset(ldpcs, 0, sizeof(ldpcs)); // useless as initialization comes next
for (int sf = 0; sf <= 1; ++sf)
{
for (int fec = 0; fec < FEC_COUNT; ++fec)
{
const fec_info *fi = &fec_infos[sf][fec];
if (!fi->ldpc)
{
ldpcs[sf][fec] = nullptr;
}
else
{
int n = (sf ? 64800 / 4 : 64800);
int k = fi->kldpc;
ldpcs[sf][fec] = new s2_ldpc_engine(fi->ldpc, k, n);
}
}
}
}
~s2_ldpc_engines()
{
for (int sf = 0; sf <= 1; ++sf)
{
for (int fec = 0; fec < FEC_COUNT; ++fec)
{
if (ldpcs[sf][fec]) {
delete ldpcs[sf][fec];
}
}
}
}
void print_node_stats()
{
for (int sf = 0; sf <= 1; ++sf)
{
for (int fec = 0; fec < FEC_COUNT; ++fec)
{
s2_ldpc_engine *ldpc = ldpcs[sf][fec];
if (ldpc) {
ldpc->print_node_stats();
}
}
}
}
}; // s2_ldpc_engines
// S2_BCH_ENGINES
// Initializes BCH engines for all DVB-S2 FEC settings.
struct s2_bch_engines
{
bch_interface *bchs[2][FEC_COUNT];
// N=t*m
// The generator of GF(2^m) is always g1.
// Normal frames with 8, 10 or 12 polynomials.
typedef bch_engine<uint32_t, 192, 17, 16, uint16_t, 0x002d> s2_bch_engine_nf12;
typedef bch_engine<uint32_t, 160, 17, 16, uint16_t, 0x002d> s2_bch_engine_nf10;
typedef bch_engine<uint32_t, 128, 17, 16, uint16_t, 0x002d> s2_bch_engine_nf8;
// Short frames with 12 polynomials.
typedef bch_engine<uint32_t, 168, 17, 14, uint16_t, 0x002b> s2_bch_engine_sf12;
s2_bch_engines()
{
bitvect<uint32_t, 17> bch_polys[2][12]; // [shortframes][polyindex]
// EN 302 307-1 5.3.1 Table 6a (polynomials for normal frames)
bch_polys[0][0] = bitvect<uint32_t, 17>(0x1002d); // g1
bch_polys[0][1] = bitvect<uint32_t, 17>(0x10173); // g2
bch_polys[0][2] = bitvect<uint32_t, 17>(0x10fbd); // g3
bch_polys[0][3] = bitvect<uint32_t, 17>(0x15a55); // g4
bch_polys[0][4] = bitvect<uint32_t, 17>(0x11f2f); // g5
bch_polys[0][5] = bitvect<uint32_t, 17>(0x1f7b5); // g6
bch_polys[0][6] = bitvect<uint32_t, 17>(0x1af65); // g7
bch_polys[0][7] = bitvect<uint32_t, 17>(0x17367); // g8
bch_polys[0][8] = bitvect<uint32_t, 17>(0x10ea1); // g9
bch_polys[0][9] = bitvect<uint32_t, 17>(0x175a7); // g10
bch_polys[0][10] = bitvect<uint32_t, 17>(0x13a2d); // g11
bch_polys[0][11] = bitvect<uint32_t, 17>(0x11ae3); // g12
// EN 302 307-1 5.3.1 Table 6b (polynomials for short frames)
bch_polys[1][0] = bitvect<uint32_t, 17>(0x402b); // g1
bch_polys[1][1] = bitvect<uint32_t, 17>(0x4941); // g2
bch_polys[1][2] = bitvect<uint32_t, 17>(0x4647); // g3
bch_polys[1][3] = bitvect<uint32_t, 17>(0x5591); // g4
bch_polys[1][4] = bitvect<uint32_t, 17>(0x6b55); // g5
bch_polys[1][5] = bitvect<uint32_t, 17>(0x6389); // g6
bch_polys[1][6] = bitvect<uint32_t, 17>(0x6ce5); // g7
bch_polys[1][7] = bitvect<uint32_t, 17>(0x4f21); // g8
bch_polys[1][8] = bitvect<uint32_t, 17>(0x460f); // g9
bch_polys[1][9] = bitvect<uint32_t, 17>(0x5a49); // g10
bch_polys[1][10] = bitvect<uint32_t, 17>(0x5811); // g11
bch_polys[1][11] = bitvect<uint32_t, 17>(0x65ef); // g12
// Redundant with fec_infos[], but needs static template argument.
for (int sf = 0; sf <= 1; ++sf)
{
for (int fec = 0; fec < FEC_COUNT; ++fec) {
bchs[sf][fec] = nullptr;
}
}
bchs[0][FEC12] = new s2_bch_engine_nf12(bch_polys[0], 12);
bchs[0][FEC23] = new s2_bch_engine_nf10(bch_polys[0], 10);
bchs[0][FEC34] = new s2_bch_engine_nf12(bch_polys[0], 12);
bchs[0][FEC56] = new s2_bch_engine_nf10(bch_polys[0], 10);
bchs[0][FEC45] = new s2_bch_engine_nf12(bch_polys[0], 12);
bchs[0][FEC89] = new s2_bch_engine_nf8(bch_polys[0], 8);
bchs[0][FEC910] = new s2_bch_engine_nf8(bch_polys[0], 8);
bchs[0][FEC14] = new s2_bch_engine_nf12(bch_polys[0], 12);
bchs[0][FEC13] = new s2_bch_engine_nf12(bch_polys[0], 12);
bchs[0][FEC25] = new s2_bch_engine_nf12(bch_polys[0], 12);
bchs[0][FEC35] = new s2_bch_engine_nf12(bch_polys[0], 12);
bchs[1][FEC12] = new s2_bch_engine_sf12(bch_polys[1], 12);
bchs[1][FEC23] = new s2_bch_engine_sf12(bch_polys[1], 12);
bchs[1][FEC34] = new s2_bch_engine_sf12(bch_polys[1], 12);
bchs[1][FEC56] = new s2_bch_engine_sf12(bch_polys[1], 12);
bchs[1][FEC45] = new s2_bch_engine_sf12(bch_polys[1], 12);
bchs[1][FEC89] = new s2_bch_engine_sf12(bch_polys[1], 12);
bchs[1][FEC14] = new s2_bch_engine_sf12(bch_polys[1], 12);
bchs[1][FEC13] = new s2_bch_engine_sf12(bch_polys[1], 12);
bchs[1][FEC25] = new s2_bch_engine_sf12(bch_polys[1], 12);
bchs[1][FEC35] = new s2_bch_engine_sf12(bch_polys[1], 12);
}
~s2_bch_engines()
{
for (int sf = 0; sf <= 1; ++sf)
{
for (int fec = 0; fec < FEC_COUNT; ++fec)
{
if (bchs[sf][fec]) {
delete bchs[sf][fec];
}
}
}
}
}; // s2_bch_engines
// S2 BASEBAND DESCRAMBLER AND FEC ENCODER
// EN 302 307-1 section 5.2.2
// EN 302 307-1 section 5.3
struct s2_fecenc : runnable
{
typedef ldpc_engine<bool, hard_sb, 8, uint16_t> s2_ldpc_engine;
s2_fecenc(
scheduler *sch,
pipebuf<bbframe> &_in,
pipebuf<fecframe<hard_sb>> &_out
) :
runnable(sch, "S2 fecenc"),
in(_in),
out(_out)
{
if (sch->debug) {
s2ldpc.print_node_stats();
}
}
void run()
{
while (in.readable() >= 1 && out.writable() >= 1)
{
run_frame(in.rd(), out.wr());
in.read(1);
out.written(1);
}
}
private:
void run_frame(const bbframe *pin, fecframe<hard_sb> *pout)
{
const modcod_info *mcinfo = check_modcod(pin->pls.modcod);
const fec_info *fi = &fec_infos[pin->pls.sf][mcinfo->rate];
pout->pls = pin->pls;
hard_sb *pbytes = pout->bytes;
bbscrambling.transform(pin->bytes, fi->Kbch / 8, pbytes);
{ // BCH
size_t msgbytes = fi->Kbch / 8;
bch_interface *bch = s2bch.bchs[pin->pls.sf][mcinfo->rate];
bch->encode(pbytes, msgbytes, pbytes + msgbytes);
}
{ // LDPC
size_t msgbits = fi->kldpc;
size_t cwbits = pin->pls.framebits();
s2_ldpc_engine *ldpc = s2ldpc.ldpcs[pin->pls.sf][mcinfo->rate];
ldpc->encode(fi->ldpc, pbytes, msgbits, cwbits, pbytes + msgbits / 8);
}
}
pipereader<bbframe> in;
pipewriter<fecframe<hard_sb>> out;
s2_bbscrambling bbscrambling;
s2_bch_engines s2bch;
s2_ldpc_engines<bool, hard_sb> s2ldpc;
}; // s2_fecenc
// S2 FEC DECODER AND BASEBAND DESCRAMBLER
// EN 302 307-1 section 5.3
// EN 302 307-1 section 5.2.2
template <typename SOFTBIT, typename SOFTBYTE>
struct s2_fecdec : runnable
{
int bitflips;
s2_fecdec(
scheduler *sch,
pipebuf<fecframe<SOFTBYTE>> &_in, pipebuf<bbframe> &_out,
pipebuf<int> *_bitcount = nullptr,
pipebuf<int> *_errcount = nullptr
) :
runnable(sch, "S2 fecdec"),
bitflips(0),
in(_in),
out(_out),
bitcount(opt_writer(_bitcount, 1)),
errcount(opt_writer(_errcount, 1))
{
if (sch->debug) {
s2ldpc.print_node_stats();
}
}
void run()
{
while (in.readable() >= 1 && out.writable() >= 1 &&
opt_writable(bitcount, 1) && opt_writable(errcount, 1))
{
fecframe<SOFTBYTE> *pin = in.rd();
const modcod_info *mcinfo = check_modcod(pin->pls.modcod);
const fec_info *fi = &fec_infos[pin->pls.sf][mcinfo->rate];
bool corrupted = false;
bool residual_errors;
if (true)
{
// LDPC decode
size_t cwbits = pin->pls.framebits();
size_t msgbits = fi->kldpc;
s2_ldpc_engine *ldpc = s2ldpc.ldpcs[pin->pls.sf][mcinfo->rate];
int ncorr = ldpc->decode_bitflip(fi->ldpc, pin->bytes, msgbits, cwbits, bitflips);
if (sch->debug2) {
fprintf(stderr, "LDPCCORR = %d\n", ncorr);
}
}
uint8_t *hardbytes = softbytes_harden(pin->bytes, fi->kldpc / 8, bch_buf);
if (true)
{
// BCH decode
size_t cwbytes = fi->kldpc / 8;
// Decode with suitable BCH decoder for this MODCOD
bch_interface *bch = s2bch.bchs[pin->pls.sf][mcinfo->rate];
int ncorr = bch->decode(hardbytes, cwbytes);
if (sch->debug2) {
fprintf(stderr, "BCHCORR = %d\n", ncorr);
}
corrupted = (ncorr < 0);
residual_errors = (ncorr != 0);
// Report VER
opt_write(bitcount, fi->Kbch);
opt_write(errcount, (ncorr >= 0) ? ncorr : fi->Kbch);
}
int bbsize = fi->Kbch / 8;
// TBD Some decoders want the bad packets.
#if 0
if ( corrupted ) {
fprintf(stderr, "Passing bad frame\n");
corrupted = false;
}
#endif
if (!corrupted)
{
// Descramble and output
bbframe *pout = out.wr();
pout->pls = pin->pls;
bbscrambling.transform(hardbytes, bbsize, pout->bytes);
out.written(1);
}
if (sch->debug) {
fprintf(stderr, "%c", corrupted ? ':' : residual_errors ? '.' : '_');
}
in.read(1);
}
}
private:
s2_ldpc_engines<SOFTBIT, SOFTBYTE> s2ldpc;
uint8_t bch_buf[64800 / 8]; // Temp storage for hardening before BCH
s2_bch_engines s2bch;
s2_bbscrambling bbscrambling;
pipereader<fecframe<SOFTBYTE>> in;
pipewriter<bbframe> out;
pipewriter<int> *bitcount, *errcount;
}; // s2_fecdec
#ifdef LINUX
// Soft LDPC decoder
// Internally implemented LDPC tool. Replaces external LDPC decoder
template <typename SOFTBIT, typename SOFTBYTE>
struct s2_fecdec_soft : runnable
{
s2_fecdec_soft(
scheduler *sch,
pipebuf<fecframe<SOFTBYTE>> &_in,
pipebuf<bbframe> &_out,
int _modcod,
bool _shortframes = true,
int _max_trials = 25,
pipebuf<int> *_bitcount = nullptr,
pipebuf<int> *_errcount = nullptr
) :
runnable(sch, "S2 fecdec soft"),
in(_in),
out(_out),
modcod(_modcod < 0 ? 0 : _modcod > 31 ? 31 : _modcod),
shortframes(_shortframes ? 1 : 0),
max_trials(_max_trials),
bitcount(opt_writer(_bitcount, 1)),
errcount(opt_writer(_errcount, 1))
{
const char *tabname = ldpctool::LDPCInterface::mc_tabnames[shortframes][modcod];
fprintf(stderr, "s2_fecdec_soft::s2_fecdec_soft: tabname: %s\n", tabname);
if (tabname)
{
ldpc = ldpctool::create_ldpc((char *)"S2", tabname[0], atoi(tabname + 1));
code = new ldpctool::code_type[ldpc->code_len()];
aligned_buffer = aligned_alloc(sizeof(ldpctool::simd_type), sizeof(ldpctool::simd_type) * ldpc->code_len());
simd = reinterpret_cast<ldpctool::simd_type *>(aligned_buffer);
}
else
{
ldpc = nullptr;
aligned_buffer = nullptr;
code = nullptr;
}
}
~s2_fecdec_soft()
{
if (ldpc) {
delete ldpc;
}
if (aligned_buffer) {
free(aligned_buffer);
}
if (code) {
delete[] code;
}
}
void run()
{
while (in.readable() >= 1 &&
out.writable() >= 1 &&
opt_writable(bitcount, 1) &&
opt_writable(errcount, 1))
{
fecframe<SOFTBYTE> *pin = in.rd();
const modcod_info *mcinfo = check_modcod(pin->pls.modcod);
const fec_info *fi = &fec_infos[pin->pls.sf][mcinfo->rate];
bool corrupted = false;
bool residual_errors;
if (ldpc)
{
decode.init(ldpc);
int count = decode(simd, simd + ldpc->data_len(), max_trials, 1);
if (count < 0) {
fprintf(stderr, "s2_fecdec_soft::run: decoder failed at converging to a code word in %d trials\n", max_trials);
}
for (int i = 0; i < ldpc->code_len(); ++i) {
code[i] = reinterpret_cast<ldpctool::code_type *>(simd + i)[0];
}
SOFTBYTE *ldpc_buf = reinterpret_cast<SOFTBYTE*>(code);
uint8_t *hardbytes = softbytes_harden(ldpc_buf, fi->kldpc / 8, bch_buf);
// BCH decode
size_t cwbytes = fi->kldpc / 8;
// Decode with suitable BCH decoder for this MODCOD
bch_interface *bch = s2bch.bchs[pin->pls.sf][mcinfo->rate];
int ncorr = bch->decode(hardbytes, cwbytes);
if (sch->debug2) {
fprintf(stderr, "BCHCORR = %d\n", ncorr);
}
corrupted = (ncorr < 0);
residual_errors = (ncorr != 0);
// Report VER
opt_write(bitcount, fi->Kbch);
opt_write(errcount, (ncorr >= 0) ? ncorr : fi->Kbch);
int bbsize = fi->Kbch / 8;
if (!corrupted)
{
// Descramble and output
bbframe *pout = out.wr();
pout->pls = pin->pls;
bbscrambling.transform(hardbytes, bbsize, pout->bytes);
out.written(1);
}
if (sch->debug) {
fprintf(stderr, "%c", corrupted ? ':' : residual_errors ? '.' : '_');
}
} // ldpc engine allocated
in.read(1);
}
}
private:
pipereader<fecframe<SOFTBYTE>> in;
pipewriter<bbframe> out;
int modcod;
int shortframes;
int max_trials;
pipewriter<int> *bitcount, *errcount;
typedef ldpctool::NormalUpdate<ldpctool::simd_type> update_type;
//typedef SelfCorrectedUpdate<simd_type> update_type;
//typedef MinSumAlgorithm<simd_type, update_type> algorithm_type;
//typedef OffsetMinSumAlgorithm<simd_type, update_type, FACTOR> algorithm_type;
typedef ldpctool::MinSumCAlgorithm<ldpctool::simd_type, update_type, ldpctool::FACTOR> algorithm_type;
//typedef LogDomainSPA<simd_type, update_type> algorithm_type;
//typedef LambdaMinAlgorithm<simd_type, update_type, 3> algorithm_type;
//typedef SumProductAlgorithm<simd_type, update_type> algorithm_type;
ldpctool::LDPCDecoder<ldpctool::simd_type, algorithm_type> decode;
ldpctool::LDPCInterface *ldpc;
ldpctool::code_type *code;
void *aligned_buffer;
ldpctool::simd_type *simd;
uint8_t bch_buf[64800 / 8]; // Temp storage for hardening before BCH
s2_bch_engines s2bch;
s2_bbscrambling bbscrambling;
}; // s2_fecdec_soft
// External LDPC decoder
// Spawns a user-specified command, FEC frames on stdin/stdout.
template <typename T, int _SIZE>
struct simplequeue
{
static const int SIZE = _SIZE;
simplequeue()
{
rd = wr = count = 0;
}
bool full() { return count == SIZE; }
T *put()
{
T *res = &q[wr];
wr = (wr + 1) % SIZE;
++count;
return res;
}
bool empty() { return count == 0; }
const T *peek() { return &q[rd]; }
const T *get()
{
const T *res = &q[rd];
rd = (rd + 1) % SIZE;
--count;
return res;
}
private:
int rd, wr, count;
T q[SIZE];
};
template <typename SOFTBIT, typename SOFTBYTE>
struct s2_fecdec_helper : runnable
{
int batch_size;
int nhelpers;
bool must_buffer;
int max_trials;
s2_fecdec_helper(
scheduler *sch,
pipebuf<fecframe<SOFTBYTE>> &_in,
pipebuf<bbframe> &_out,
const char *_command,
pipebuf<int> *_bitcount = nullptr,
pipebuf<int> *_errcount = nullptr
) :
runnable(sch, "S2 fecdec io"),
batch_size(16),
nhelpers(1),
must_buffer(false),
max_trials(8),
in(_in),
out(_out),
bitcount(opt_writer(_bitcount, 1)),
errcount(opt_writer(_errcount, 1))
{
command = strdup(_command);
for (int mc = 0; mc < 32; ++mc) {
for (int sf = 0; sf < 2; ++sf) {
pools[mc][sf].procs = nullptr;
}
}
}
~s2_fecdec_helper()
{
free(command);
killall(); // also deletes pools[mc][sf].procs if necessary
}
void run()
{
// Send work until all helpers block.
while (in.readable() >= 1 && !jobs.full())
{
if ((bbframe_q.size() != 0) && (out.writable() >= 1))
{
bbframe *pout = out.wr();
pout->pls = bbframe_q.front().pls;
std::copy(bbframe_q.front().bytes, bbframe_q.front().bytes + (58192 / 8), pout->bytes);
bbframe_q.pop_front();
out.written(1);
}
if ((bitcount_q.size() != 0) && opt_writable(bitcount, 1))
{
opt_write(bitcount, bitcount_q.front());
bitcount_q.pop_front();
}
if ((errcount_q.size() != 0) && opt_writable(errcount, 1))
{
opt_write(errcount, errcount_q.front());
errcount_q.pop_front();
}
if (!jobs.empty() && jobs.peek()->h->b_out) {
receive_frame(jobs.get());
}
send_frame(in.rd());
in.read(1);
}
}
private:
struct helper_instance
{
int fd_tx; // To helper
int fd_rx; // From helper
int batch_size; // Latency
int b_in; // Jobs in input queue
int b_out; // Jobs in output queue
int pid; // PID of the child
};
struct pool
{
helper_instance *procs; // nullptr or [nprocs]
int nprocs;
int shift;
} pools[32][2]; // [modcod][sf]
struct helper_job
{
s2_pls pls;
helper_instance *h;
};
simplequeue<helper_job, 1024> jobs;
// Try to send a frame. Return false if helper was busy.
bool send_frame(fecframe<SOFTBYTE> *pin)
{
pool *p = get_pool(&pin->pls);
for (int j = 0; j < p->nprocs; ++j)
{
int i = (p->shift + j) % p->nprocs;
helper_instance *h = &p->procs[i];
int iosize = (pin->pls.framebits() / 8) * sizeof(SOFTBYTE);
// fprintf(stderr, "Writing %lu to fd %d\n", iosize, h->fd_tx);
int nw = write(h->fd_tx, pin->bytes, iosize);
if (nw < 0 && errno == EWOULDBLOCK)
{
//lseek(h->fd_tx, 0, SEEK_SET); // allow new writes on this worker
//fprintf(stderr, "s2_fecdec_helper::send_frame: %d worker is busy\n", h->pid);
continue; // next worker
}
if (nw < 0) {
fatal("write(LDPC helper");
} else if (nw != iosize) {
fatal("partial write(LDPC helper)");
}
p->shift = i;
helper_job *job = jobs.put();
job->pls = pin->pls;
job->h = h;
++h->b_in;
if (h->b_in >= h->batch_size)
{
h->b_in -= h->batch_size;
h->b_out += h->batch_size;
}
return true; // done sent to worker
}
fprintf(stderr, "s2_fecdec_helper::send_frame: WARNING: all %d workers were busy: modcod=%d sf=%d)\n",
p->nprocs, pin->pls.modcod, pin->pls.sf);
return false; // all workers were busy
}
// Return a pool of running helpers for a given modcod.
pool *get_pool(const s2_pls *pls)
{
pool *p = &pools[pls->modcod][pls->sf];
if (!p->procs)
{
fprintf(stderr, "s2_fecdec_helper::get_pool: allocate %d workers: modcod=%d sf=%d\n",
nhelpers, pls->modcod, pls->sf);
p->procs = new helper_instance[nhelpers];
for (int i = 0; i < nhelpers; ++i) {
spawn_helper(&p->procs[i], pls);
}
p->nprocs = nhelpers;
p->shift = 0;
}
return p;
}
void killall()
{
fprintf(stderr, "s2_fecdec_helper::killall\n");
for (int i = 0; i < 32; i++) // all MODCODs
{
for (int j = 0; j < 2; j++) // long and short frames
{
pool *p = &pools[i][j];
if (p->procs)
{
for (int i = 0; i < p->nprocs; ++i)
{
helper_instance *h = &p->procs[i];
fprintf(stderr, "s2_fecdec_helper::killall: killing %d\n", h->pid);
int rc = kill(h->pid, SIGKILL);
if (rc < 0)
{
fatal("s2_fecdec_helper::killall");
}
else
{
int cs;
waitpid(h->pid, &cs, 0);
}
// close pipes
close(h->fd_tx);
close(h->fd_rx);
}
delete p->procs;
p->procs = nullptr;
p->nprocs = 0;
}
} // long and short frames
} // all MODCODs
}
// Spawn a helper process.
void spawn_helper(helper_instance *h, const s2_pls *pls)
{
if (sch->debug) {
fprintf(stderr, "Spawning LDPC helper: modcod=%d sf=%d\n", pls->modcod, pls->sf);
}
int tx[2], rx[2];
if (pipe(tx) || pipe(rx)) {
fatal("pipe");
}
// Size the pipes so that the helper never runs out of work to do.
int pipesize = 64800 * batch_size;
// macOS does not have F_SETPIPE_SZ and there
// is no way to change the buffer size
#ifndef __APPLE__
long min_pipe_size = (long) fcntl(tx[0], F_GETPIPE_SZ);
long pipe_size = (long) fcntl(rx[0], F_GETPIPE_SZ);
min_pipe_size = std::min(min_pipe_size, pipe_size);
pipe_size = (long) fcntl(tx[1], F_GETPIPE_SZ);
min_pipe_size = std::min(min_pipe_size, pipe_size);
pipe_size = (long) fcntl(rx[1], F_GETPIPE_SZ);
min_pipe_size = std::min(min_pipe_size, pipe_size);
if (min_pipe_size < pipesize)
{
if (fcntl(tx[0], F_SETPIPE_SZ, pipesize) < 0 ||
fcntl(rx[0], F_SETPIPE_SZ, pipesize) < 0 ||
fcntl(tx[1], F_SETPIPE_SZ, pipesize) < 0 ||
fcntl(rx[1], F_SETPIPE_SZ, pipesize) < 0)
{
fprintf(stderr,
"*** Failed to increase pipe size from %ld.\n"
"*** Try echo %d > /proc/sys/fs/pipe-max-size\n",
min_pipe_size,
pipesize);
if (must_buffer) {
fatal("F_SETPIPE_SZ");
} else {
fprintf(stderr, "*** Throughput will be suboptimal.\n");
}
}
}
#endif
// vfork() differs from fork(2) in that the calling thread is
// suspended until the child terminates
int child = fork();
if (!child)
{
// Child process
close(tx[1]);
dup2(tx[0], 0);
close(rx[0]);
dup2(rx[1], 1);
char max_trials_arg[16];
sprintf(max_trials_arg, "%d", max_trials);
char batch_size_arg[16];
sprintf(batch_size_arg, "%d", batch_size);
char mc_arg[16];
sprintf(mc_arg, "%d", pls->modcod);
const char *sf_arg = pls->sf ? "--shortframes" : nullptr;
const char *argv[] = {
command,
"--trials", max_trials_arg,
"--batch-size", batch_size_arg,
"--modcod", mc_arg,
sf_arg,
nullptr
};
execve(command, (char *const *)argv, nullptr);
fatal(command);
}
h->pid = child;
h->fd_tx = tx[1];
close(tx[0]);
h->fd_rx = rx[0];
close(rx[1]);
h->batch_size = batch_size; // TBD
h->b_in = h->b_out = 0;
int flags_tx = fcntl(h->fd_tx, F_GETFL);
if (fcntl(h->fd_tx, F_SETFL, flags_tx | O_NONBLOCK)) {
fatal("fcntl_tx(helper)");
}
int flags_rx = fcntl(h->fd_rx, F_GETFL);
if (fcntl(h->fd_rx, F_SETFL, flags_rx | O_NONBLOCK)) {
fatal("fcntl_rx(helper)");
}
}
// Receive a finished job.
void receive_frame(const helper_job *job)
{
// Read corrected frame from helper
const s2_pls *pls = &job->pls;
int iosize = (pls->framebits() / 8) * sizeof(ldpc_buf[0]);
int nr = read(job->h->fd_rx, ldpc_buf, iosize);
if (nr < 0)
{
if (errno != EAGAIN) { // if no data then try again next time
fatal("s2_fecdec_helper::receive_frame read error");
}
}
else if (nr != iosize)
{
fprintf(stderr, "s2_fecdec_helper::receive_frame: %d bytes read vs %d\n", nr, iosize);
}
--job->h->b_out;
// Decode BCH.
const modcod_info *mcinfo = check_modcod(job->pls.modcod);
const fec_info *fi = &fec_infos[job->pls.sf][mcinfo->rate];
uint8_t *hardbytes = softbytes_harden(ldpc_buf, fi->kldpc / 8, bch_buf);
size_t cwbytes = fi->kldpc / 8;
//size_t msgbytes = fi->Kbch / 8;
//size_t chkbytes = cwbytes - msgbytes;
bch_interface *bch = s2bch.bchs[job->pls.sf][mcinfo->rate];
int ncorr = bch->decode(hardbytes, cwbytes);
if (sch->debug2) {
fprintf(stderr, "BCHCORR = %d\n", ncorr);
}
bool corrupted = (ncorr < 0);
// Report VBER
bitcount_q.push_back(fi->Kbch);
//opt_write(bitcount, fi->Kbch);
errcount_q.push_front((ncorr >= 0) ? ncorr : fi->Kbch);
//opt_write(errcount, (ncorr >= 0) ? ncorr : fi->Kbch);
#if 0
// TBD Some decoders want the bad packets.
if ( corrupted ) {
fprintf(stderr, "Passing bad frame\n");
corrupted = false;
}
#endif
if (!corrupted)
{
// Descramble and output
bbframe_q.emplace_back();
//bbframe *pout = out.wr();
bbframe_q.back().pls = job->pls;
bbscrambling.transform(hardbytes, fi->Kbch / 8, bbframe_q.back().bytes);
//out.written(1);
}
if (sch->debug) {
fprintf(stderr, "%c", corrupted ? '!' : ncorr ? '.' : '_');
}
}
pipereader<fecframe<SOFTBYTE>> in;
pipewriter<bbframe> out;
char *command;
SOFTBYTE ldpc_buf[64800 / 8];
uint8_t bch_buf[64800 / 8]; // Temp storage for hardening before BCH
s2_bch_engines s2bch;
s2_bbscrambling bbscrambling;
std::deque<bbframe> bbframe_q;
std::deque<int> bitcount_q;
std::deque<int> errcount_q;
pipewriter<int> *bitcount, *errcount;
}; // s2_fecdec_helper
#endif
// S2 FRAMER
// EN 302 307-1 section 5.1 Mode adaptation
struct s2_framer : runnable
{
uint8_t rolloff_code; // 0=0.35, 1=0.25, 2=0.20, 3=reserved
// User must provide pls_seq[n_pls_seq].
// For ACM, user can change pls_seq[0] at runtime.
// For VCM with a repeating pattern, use n_pls_seq>=2.
s2_pls *pls_seq;
int n_pls_seq;
s2_framer(
scheduler *sch,
pipebuf<tspacket> &_in,
pipebuf<bbframe> &_out
) :
runnable(sch, "S2 framer"),
n_pls_seq(0),
pls_index(0),
in(_in),
out(_out)
{
nremain = 0;
remcrc = 0; // CRC for nonexistent previous packet
}
void run()
{
while (out.writable() >= 1)
{
if (!n_pls_seq ) {
fail("PLS not specified");
}
s2_pls *pls = &pls_seq[pls_index];
const modcod_info *mcinfo = check_modcod(pls->modcod);
const fec_info *fi = &fec_infos[pls->sf][mcinfo->rate];
int framebytes = fi->Kbch / 8;
if (!framebytes) {
fail("MODCOD/framesize combination not allowed");
}
if (10 + nremain + 188 * in.readable() < framebytes) {
break; // Not enough data to fill a frame
}
bbframe *pout = out.wr();
pout->pls = *pls;
uint8_t *buf = pout->bytes;
uint8_t *end = buf + framebytes;
// EN 302 307-1 section 5.1.6 Base-Band Header insertion
uint8_t *bbheader = buf;
uint8_t matype1 = 0;
matype1 |= 0xc0; // TS
matype1 |= 0x20; // SIS
matype1 |= (n_pls_seq==1) ? 0x10 : 0x00; // CCM/ACM
// TBD ISSY/NPD required for ACM ?
matype1 |= rolloff_code;
*buf++ = matype1; // MATYPE-1
*buf++ = 0; // MATYPE-2
uint16_t upl = 188 * 8;
*buf++ = upl >> 8; // UPL MSB
*buf++ = upl; // UPL LSB
uint16_t dfl = (framebytes - 10) * 8;
*buf++ = dfl >> 8; // DFL MSB
*buf++ = dfl; // DFL LSB
*buf++ = 0x47; // SYNC
uint16_t syncd = nremain * 8;
*buf++ = syncd >> 8; // SYNCD MSB
*buf++ = syncd; // SYNCD LSB
*buf++ = crc8.compute(bbheader, 9);
// Data field
memcpy(buf, rembuf, nremain); // Leftover from previous runs
buf += nremain;
while (buf < end)
{
tspacket *tsp = in.rd();
if (tsp->data[0] != MPEG_SYNC) {
fail("Invalid TS");
}
*buf++ = remcrc; // Replace SYNC with CRC of previous.
remcrc = crc8.compute(tsp->data + 1, tspacket::SIZE - 1);
int nused = end - buf;
if (nused > tspacket::SIZE - 1) {
nused = tspacket::SIZE - 1;
}
memcpy(buf, tsp->data + 1, nused);
buf += nused;
if (buf == end)
{
nremain = (tspacket::SIZE - 1) - nused;
memcpy(rembuf, tsp->data + 1 + nused, nremain);
}
in.read(1);
}
if (buf != end) {
fail("Bug: s2_framer");
}
out.written(1);
++pls_index;
if (pls_index == n_pls_seq) {
pls_index = 0;
}
}
}
private:
int pls_index; // Next slot to use in pls_seq
pipereader<tspacket> in;
pipewriter<bbframe> out;
crc8_engine crc8;
int nremain;
uint8_t rembuf[tspacket::SIZE];
uint8_t remcrc;
}; // s2_framer
// S2 DEFRAMER
// EN 302 307-1 section 5.1 Mode adaptation
struct s2_deframer : runnable
{
int fd_gse; // FD for generic streams, or -1
s2_deframer(
scheduler *sch,
pipebuf<bbframe> &_in,
pipebuf<tspacket> &_out,
pipebuf<int> *_state_out = nullptr,
pipebuf<unsigned long> *_locktime_out = nullptr
) :
runnable(sch, "S2 deframer"),
fd_gse(-1),
nleftover(-1),
in(_in),
out(_out, MAX_TS_PER_BBFRAME),
current_state(false),
state_out(opt_writer(_state_out, 2)),
report_state(true),
locktime(0),
locktime_out(opt_writer(_locktime_out, MAX_TS_PER_BBFRAME))
{
}
void run()
{
while (in.readable() >= 1 && out.writable() >= MAX_TS_PER_BBFRAME &&
opt_writable(state_out, 2) &&
opt_writable(locktime_out, MAX_TS_PER_BBFRAME))
{
if (report_state)
{
// Report unlocked state on first invocation.
opt_write(state_out, 0);
report_state = false;
}
run_bbframe(in.rd());
in.read(1);
}
}
private:
void run_bbframe(bbframe *pin)
{
uint8_t *bbh = pin->bytes;
// EN 302 307 section 5.1.6 Base-Band Header Insertion
uint8_t streamtype = bbh[0] >> 6;
bool sis = bbh[0] & 32;
bool ccm = bbh[0] & 16;
bool issyi = bbh[0] & 8;
bool npd = bbh[0] & 4;
int ro_code = bbh[0] & 3;
uint8_t isi = bbh[1]; // if !sis
uint16_t upl = (bbh[2] << 8) | bbh[3];
uint16_t dfl = (bbh[4] << 8) | bbh[5];
uint8_t sync = bbh[6];
uint16_t syncd = (bbh[7] << 8) | bbh[8];
uint8_t crcexp = crc8.compute(bbh, 9);
uint8_t crc = bbh[9];
uint8_t *data = bbh + 10;
if (sch->debug2)
{
static const char *stnames[] = { "GP", "GC", "??", "TS" };
static float ro_values[] = {0.35, 0.25, 0.20, 0};
fprintf(stderr, "BBH: crc %02x/%02x(%s) %s %s(ISI=%d) %s%s%s ro=%.2f"
" upl=%d dfl=%d sync=%02x syncd=%d\n",
crc,
crcexp,
(crc == crcexp) ? "OK" : "KO",
stnames[streamtype],
(sis ? "SIS" : "MIS"),
isi,
(ccm ? "CCM" : "ACM"),
(issyi ? " ISSYI": ""),
(npd ? " NPD" : ""),
ro_values[ro_code],
upl,
dfl,
sync,
syncd
);
}
if (crc != crcexp || dfl > fec_info::KBCH_MAX)
{
// Note: Maybe accept syncd=65535
if (sch->debug) {
fprintf(stderr, "Bad bbframe\n");
}
nleftover = -1;
info_unlocked();
return; // Max one state_out per loop
}
// TBD: Supporting byte-oriented payloads only.
if ((dfl&7) || (syncd&7))
{
fprintf(stderr, "Unsupported bbframe\n");
nleftover = -1;
info_unlocked();
return; // Max one state_out per loop
}
if (streamtype==3 && upl==188*8 && sync==0x47 && syncd<=dfl)
{
handle_ts(data, dfl, syncd, sync);
}
else if (streamtype == 1)
{
if (fd_gse >= 0)
{
ssize_t nw = write(fd_gse, data, dfl/8);
if (nw < 0) {
fatal("write(gse)");
}
if (nw != dfl/8) {
fail("partial write(gse");
}
}
else
{
fprintf(stderr, "Unrecognized bbframe\n");
}
}
}
void handle_ts(uint8_t *data, uint16_t dfl, uint16_t syncd, uint8_t sync)
{
int pos; // Start of useful data in this bbframe
if (nleftover < 0)
{
// Not synced. Skip unusable data at beginning of bbframe
pos = syncd / 8;
if (sch->debug) {
fprintf(stderr, "Start TS at %d\n", pos);
}
nleftover = 0;
}
else
{
// Sanity check
if (syncd / 8 != 188 - nleftover)
{
if (sch->debug) {
fprintf(stderr, "Lost a bbframe ?\n");
}
nleftover = -1;
info_unlocked();
return; // Max one state_out per loop
}
pos = 0;
}
while ( pos+(188-nleftover)+1 <= dfl/8 )
{
// Enough data available for one packet and its CRC.
tspacket *pout = out.wr();
memcpy(pout->data, leftover, nleftover); // NOP most of the time
memcpy(pout->data+nleftover, data+pos, 188-nleftover);
pout->data[0] = sync; // Replace CRC
uint8_t crc = crc8.compute(pout->data+1, 188-1);
if (data[pos+(188-nleftover)] == crc)
{
info_good_packet();
}
else
{
pout->data[1] |= 0x80; // Set TEI bit
if (sch->debug) {
fprintf(stderr, "C");
}
}
out.written(1);
pos += 188 - nleftover;
nleftover = 0;
}
int remain = dfl / 8 - pos;
if (nleftover + remain > (int) sizeof(leftover)) {
fail("Bug: TS deframer");
}
memcpy(leftover+nleftover, data+pos, remain);
nleftover += remain;
}
void info_unlocked()
{
info_is_locked(false);
locktime = 0;
}
void info_good_packet()
{
info_is_locked(true);
++locktime;
opt_write(locktime_out, locktime);
}
void info_is_locked(bool newstate)
{
if (newstate != current_state)
{
opt_write(state_out, newstate ? 1 : 0);
current_state = newstate;
}
}
crc8_engine crc8;
int nleftover; // Bytes in leftover[]:
// -1 = not synced.
// 0 = no leftover data
// 1 - 187 = incomplete packet
// 188 = waiting for CRC
uint8_t leftover[188];
static const int MAX_TS_PER_BBFRAME = fec_info::KBCH_MAX / 8 / 188 + 1;
bool locked;
pipereader<bbframe> in;
pipewriter<tspacket> out;
int current_state;
pipewriter<int> *state_out;
bool report_state;
unsigned long locktime;
pipewriter<unsigned long> *locktime_out;
}; // s2_deframer
} // namespace leansdr
#endif // LEANSDR_DVBS2_H
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