mirror of
https://github.com/f4exb/sdrangel.git
synced 2024-09-12 08:06:34 -04:00
348 lines
9.7 KiB
C++
348 lines
9.7 KiB
C++
// This file is part of LeanSDR Copyright (C) 2016-2018 <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/>.
|
|
|
|
#ifndef LEANSDR_CONVOLUTIONAL_H
|
|
#define LEANSDR_CONVOLUTIONAL_H
|
|
|
|
#include "framework.h"
|
|
#include "sdr.h"
|
|
|
|
namespace leansdr
|
|
{
|
|
|
|
// ALGEBRAIC DECONVOLUTION
|
|
|
|
// QPSK 1/2 only.
|
|
// This is a straightforward implementation, provided for reference.
|
|
// deconvol_poly2 is functionally equivalent and much faster.
|
|
|
|
template <typename Tin, // Input IQ symbols
|
|
typename Thist, // Input shift register (IQIQIQ...)
|
|
Thist POLY_DECONVOL, // Taps (IQIQIQ...)
|
|
Thist POLY_ERRORS>
|
|
struct deconvol_poly
|
|
{
|
|
typedef u8 hardsymbol;
|
|
|
|
// Support soft of float input
|
|
inline u8 SYMVAL(const hardsymbol *s) { return *s; }
|
|
inline u8 SYMVAL(const softsymbol *s) { return s->symbol; }
|
|
|
|
typedef u8 decoded_byte;
|
|
|
|
deconvol_poly() : hist(0) {}
|
|
|
|
// Remap and deconvolve [nb*8] symbols into [nb] bytes.
|
|
// Return estimated number of bit errors.
|
|
|
|
int run(const Tin *pin, const u8 remap[], decoded_byte *pout, int nb)
|
|
{
|
|
int nerrors = 0;
|
|
int halfway = nb / 2;
|
|
|
|
for (; nb--; ++pout)
|
|
{
|
|
decoded_byte byte = 0;
|
|
|
|
for (int bit = 8; bit--; ++pin)
|
|
{
|
|
hist = (hist << 2) | remap[SYMVAL(pin)];
|
|
byte = (byte << 1) | parity(hist & POLY_DECONVOL);
|
|
if (nb < halfway)
|
|
nerrors += parity(hist & POLY_ERRORS);
|
|
}
|
|
|
|
*pout = byte;
|
|
}
|
|
|
|
return nerrors;
|
|
}
|
|
|
|
private:
|
|
Thist hist;
|
|
|
|
}; // deconvol_poly
|
|
|
|
// ALGEBRAIC DECONVOLUTION, OPTIMIZED
|
|
|
|
// QPSK 1/2 only.
|
|
// Functionally equivalent to deconvol_poly,
|
|
// but processing 32 bits in parallel.
|
|
|
|
template <typename Tin, // Input IQ symbols
|
|
typename Thist, // Input shift registers (one for I, one for Q)
|
|
typename Tpoly, // Taps (interleaved IQIQIQ...)
|
|
Tpoly POLY_DECONVOL,
|
|
Tpoly POLY_ERRORS>
|
|
struct deconvol_poly2
|
|
{
|
|
typedef u8 hardsymbol;
|
|
|
|
// Support instanciation of template with soft of float input
|
|
inline u8 SYMVAL(const hardsymbol *s) { return *s; }
|
|
inline u8 SYMVAL(const softsymbol *s) { return s->symbol; }
|
|
|
|
typedef u8 decoded_byte;
|
|
|
|
deconvol_poly2() : inI(0), inQ(0) {}
|
|
|
|
// Remap and deconvolve [nb*8] symbols into [nb] bytes.
|
|
// Return estimated number of bit errors.
|
|
|
|
int run(const Tin *pin, const u8 remap[], decoded_byte *pout, int nb)
|
|
{
|
|
if (nb & (sizeof(Thist) - 1)) {
|
|
fail("Must deconvolve sizeof(Thist) bytes at a time");
|
|
}
|
|
|
|
nb /= sizeof(Thist);
|
|
unsigned long nerrors = 0;
|
|
int halfway = nb / 2;
|
|
Thist histI = inI, histQ = inQ;
|
|
|
|
for (; nb--;)
|
|
{
|
|
// This is where we convolve bits in parallel.
|
|
Thist wd = 0; // decoded bits
|
|
Thist we = 0; // error bits (should be 0)
|
|
#if 0
|
|
// Trust gcc to unroll and evaluate the bit tests at compile-time.
|
|
for ( int bit=sizeof(Thist)*8; bit--; ++pin ) {
|
|
u8 iq = remap[SYMVAL(pin)];
|
|
histI = (histI<<1) | (iq>>1);
|
|
histQ = (histQ<<1) | (iq&1);
|
|
if ( POLY_DECONVOL & ((Tpoly)2<<(2*bit)) ) wd ^= histI;
|
|
if ( POLY_DECONVOL & ((Tpoly)1<<(2*bit)) ) wd ^= histQ;
|
|
if ( POLY_ERRORS & ((Tpoly)2<<(2*bit)) ) we ^= histI;
|
|
if ( POLY_ERRORS & ((Tpoly)1<<(2*bit)) ) we ^= histQ;
|
|
}
|
|
#else
|
|
// Unroll manually.
|
|
#define LOOP(bit) \
|
|
{ \
|
|
u8 iq = remap[SYMVAL(pin)]; \
|
|
histI = (histI << 1) | (iq >> 1); \
|
|
histQ = (histQ << 1) | (iq & 1); \
|
|
if (POLY_DECONVOL & ((Tpoly)2 << (2 * bit))) \
|
|
wd ^= histI; \
|
|
if (POLY_DECONVOL & ((Tpoly)1 << (2 * bit))) \
|
|
wd ^= histQ; \
|
|
if (POLY_ERRORS & ((Tpoly)2 << (2 * bit))) \
|
|
we ^= histI; \
|
|
if (POLY_ERRORS & ((Tpoly)1 << (2 * bit))) \
|
|
we ^= histQ; \
|
|
++pin; \
|
|
}
|
|
// Don't shift by more than the operand width
|
|
switch (sizeof(Thist) * 8)
|
|
{
|
|
#if 0 // Not needed yet - avoid compiler warnings
|
|
case 64:
|
|
LOOP(63); LOOP(62); LOOP(61); LOOP(60);
|
|
LOOP(59); LOOP(58); LOOP(57); LOOP(56);
|
|
LOOP(55); LOOP(54); LOOP(53); LOOP(52);
|
|
LOOP(51); LOOP(50); LOOP(49); LOOP(48);
|
|
LOOP(47); LOOP(46); LOOP(45); LOOP(44);
|
|
LOOP(43); LOOP(42); LOOP(41); LOOP(40);
|
|
LOOP(39); LOOP(38); LOOP(37); LOOP(36);
|
|
LOOP(35); LOOP(34); LOOP(33); LOOP(32);
|
|
// Fall-through
|
|
#endif
|
|
case 32:
|
|
LOOP(31);
|
|
LOOP(30);
|
|
LOOP(29);
|
|
LOOP(28);
|
|
LOOP(27);
|
|
LOOP(26);
|
|
LOOP(25);
|
|
LOOP(24);
|
|
LOOP(23);
|
|
LOOP(22);
|
|
LOOP(21);
|
|
LOOP(20);
|
|
LOOP(19);
|
|
LOOP(18);
|
|
LOOP(17);
|
|
LOOP(16);
|
|
// Fall-through
|
|
case 16:
|
|
LOOP(15);
|
|
LOOP(14);
|
|
LOOP(13);
|
|
LOOP(12);
|
|
LOOP(11);
|
|
LOOP(10);
|
|
LOOP(9);
|
|
LOOP(8);
|
|
// Fall-through
|
|
case 8:
|
|
LOOP(7);
|
|
LOOP(6);
|
|
LOOP(5);
|
|
LOOP(4);
|
|
LOOP(3);
|
|
LOOP(2);
|
|
LOOP(1);
|
|
LOOP(0);
|
|
break;
|
|
default:
|
|
fail("Thist not supported");
|
|
}
|
|
#undef LOOP
|
|
#endif
|
|
switch (sizeof(Thist) * 8)
|
|
{
|
|
#if 0 // Not needed yet - avoid compiler warnings
|
|
case 64:
|
|
*pout++ = wd >> 56;
|
|
*pout++ = wd >> 48;
|
|
*pout++ = wd >> 40;
|
|
*pout++ = wd >> 32;
|
|
// Fall-through
|
|
#endif
|
|
case 32:
|
|
*pout++ = wd >> 24;
|
|
*pout++ = wd >> 16;
|
|
// Fall-through
|
|
case 16:
|
|
*pout++ = wd >> 8;
|
|
// Fall-through
|
|
case 8:
|
|
*pout++ = wd;
|
|
break;
|
|
default:
|
|
fail("Thist not supported");
|
|
}
|
|
// Count errors when the shift registers are full
|
|
if (nb < halfway)
|
|
nerrors += hamming_weight(we);
|
|
}
|
|
|
|
inI = histI;
|
|
inQ = histQ;
|
|
return nerrors;
|
|
}
|
|
|
|
private:
|
|
Thist inI, inQ;
|
|
}; // deconvol_poly2
|
|
|
|
// CONVOLUTIONAL ENCODER
|
|
|
|
// QPSK 1/2 only.
|
|
|
|
template <typename Thist, uint64_t POLY1, uint64_t POLY2>
|
|
struct convol_poly2
|
|
{
|
|
typedef u8 uncoded_byte;
|
|
typedef u8 hardsymbol;
|
|
|
|
convol_poly2() : hist(0) {}
|
|
|
|
// Convolve [count] bytes into [count*8] symbols, and remap.
|
|
|
|
void run(const uncoded_byte *pin, const u8 remap[],
|
|
hardsymbol *pout, int count)
|
|
{
|
|
for (; count--; ++pin)
|
|
{
|
|
uncoded_byte b = *pin;
|
|
|
|
for (int bit = 8; bit--; ++pout)
|
|
{
|
|
hist = (hist >> 1) | (((b >> bit) & 1) << 6);
|
|
u8 s = (parity(hist & POLY1) << 1) | parity(hist & POLY2);
|
|
*pout = remap[s];
|
|
}
|
|
}
|
|
}
|
|
|
|
private:
|
|
Thist hist;
|
|
}; // convol_poly2
|
|
|
|
// Generic BPSK..256QAM and puncturing
|
|
|
|
template <typename Thist, int HISTSIZE>
|
|
struct convol_multipoly
|
|
{
|
|
typedef u8 uncoded_byte;
|
|
typedef u8 hardsymbol;
|
|
int bits_in, bits_out, bps;
|
|
const Thist *polys; // [bits_out]
|
|
|
|
convol_multipoly()
|
|
: bits_in(0), bits_out(0), bps(0),
|
|
hist(0), nhist(0), sersymb(0), nsersymb(0)
|
|
{
|
|
}
|
|
|
|
void encode(const uncoded_byte *pin, hardsymbol *pout, int count)
|
|
{
|
|
if (!bits_in || !bits_out || !bps) {
|
|
fatal("convol_multipoly not configured");
|
|
}
|
|
|
|
hardsymbol symbmask = (1 << bps) - 1;
|
|
|
|
for (; count--; ++pin)
|
|
{
|
|
uncoded_byte b = *pin;
|
|
|
|
for (int bit = 8; bit--;)
|
|
{
|
|
hist = (hist >> 1) | ((Thist)((b >> bit) & 1) << (HISTSIZE - 1));
|
|
++nhist;
|
|
|
|
if (nhist == bits_in)
|
|
{
|
|
for (int p = 0; p < bits_out; ++p)
|
|
{
|
|
int b = parity((Thist)(hist & polys[p]));
|
|
sersymb = (sersymb << 1) | b;
|
|
}
|
|
|
|
nhist = 0;
|
|
nsersymb += bits_out;
|
|
|
|
while (nsersymb >= bps)
|
|
{
|
|
hardsymbol s = (sersymb >> (nsersymb - bps)) & symbmask;
|
|
*pout++ = s;
|
|
nsersymb -= bps;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
// Ensure deterministic output size
|
|
// TBD We can relax this
|
|
if (nhist || nsersymb) {
|
|
fatal("partial run");
|
|
}
|
|
}
|
|
|
|
private:
|
|
Thist hist;
|
|
int nhist;
|
|
Thist sersymb;
|
|
int nsersymb;
|
|
}; // convol_multipoly
|
|
|
|
} // namespace leansdr
|
|
|
|
#endif // LEANSDR_CONVOLUTIONAL_H
|