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rtl-wmbus/rtl_wmbus.c

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Czysty Wina Historia

/*-
* Copyright (c) 2017 <xael.south@yandex.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <stdint.h>
#include <stddef.h>
#include <stdlib.h>
#include <complex.h>
#include <stdio.h>
#include <errno.h>
#include <fixedptc/fixedptc.h>
#include "fir.h"
#include "iir.h"
#include "ppf.h"
#include "moving_average_filter.h"
#include "atan2.h"
#include "net_support.h"
#include "t1_c1_packet_decoder.h"
#if !defined(__ANDROID__)
#include <immintrin.h>
#endif
static float lp_1600kHz_56kHz(int sample, size_t i_or_q)
{
static float moving_average[2];
#define ALPHA 0.80259f // exp(-2.0 * M_PI * 56e3 / 1600e3)
moving_average[i_or_q] = ALPHA * (moving_average[i_or_q] - sample) + sample;
#undef ALPHA
return moving_average[i_or_q];
}
static inline float moving_average(int sample, size_t i_or_q)
{
#define COEFFS 12
static int i_hist[COEFFS];
static int q_hist[COEFFS];
static MAVGI_FILTER filter[2] = // i/q
{
{.length = COEFFS, .hist = i_hist}, // 0
{.length = COEFFS, .hist = q_hist} // 1
};
#undef COEFFS
return mavgi(sample, &filter[i_or_q]);
}
static inline float lp_fir_butter_1600kHz_160kHz_200kHz(int sample, size_t i_or_q)
{
#define COEFFS 23
static const float b[COEFFS] = {0.000140535927, 1.102280392e-05, 0.0001309279731, 0.001356012537, 0.00551787474, 0.01499414005, 0.03160167988, 0.05525973093, 0.08315031015, 0.1099887688, 0.1295143636, 0.1366692652, 0.1295143636, 0.1099887688, 0.08315031015, 0.05525973093, 0.03160167988, 0.01499414005, 0.00551787474, 0.001356012537, 0.0001309279731, 1.102280392e-05, 0.000140535927, };
static float i_hist[COEFFS] = {};
static float q_hist[COEFFS] = {};
static FIRF_FILTER filter[2] = // i/q
{
{.length = COEFFS, .b = b, .hist = i_hist}, // 0
{.length = COEFFS, .b = b, .hist = q_hist} // 1
};
#undef COEFFS
return firf(sample, &filter[i_or_q]);
}
static inline float lp_firfp_butter_1600kHz_160kHz_200kHz(int sample, size_t i_or_q)
{
#define COEFFS 23
static const fixedpt b[COEFFS] = {fixedpt_rconst(0.000140535927), fixedpt_rconst(1.102280392e-05), fixedpt_rconst(0.0001309279731), fixedpt_rconst(0.001356012537), fixedpt_rconst(0.00551787474),
fixedpt_rconst(0.01499414005), fixedpt_rconst(0.03160167988), fixedpt_rconst(0.05525973093), fixedpt_rconst(0.08315031015), fixedpt_rconst(0.1099887688),
fixedpt_rconst(0.1295143636), fixedpt_rconst(0.1366692652), fixedpt_rconst(0.1295143636), fixedpt_rconst(0.1099887688), fixedpt_rconst(0.08315031015),
fixedpt_rconst(0.05525973093), fixedpt_rconst(0.03160167988), fixedpt_rconst(0.01499414005), fixedpt_rconst(0.00551787474), fixedpt_rconst(0.001356012537),
fixedpt_rconst(0.0001309279731), fixedpt_rconst(1.102280392e-05), fixedpt_rconst(0.000140535927),
};
static fixedpt i_hist[COEFFS] = {};
static fixedpt q_hist[COEFFS] = {};
static FIRFP_FILTER filter[2] = // i/q
{
{.length = COEFFS, .b = b, .hist = i_hist}, // 0
{.length = COEFFS, .b = b, .hist = q_hist} // 1
};
#undef COEFFS
return fixedpt_tofloat(firfp(fixedpt_fromint(sample), &filter[i_or_q]));
}
static inline float lp_ppf_butter_1600kHz_160kHz_200kHz(int sample, size_t i_or_q)
{
#define PHASES 2
#define COEFFS 12
static const float b[PHASES][COEFFS] =
{
{0.000140535927, 0.0001309279731, 0.00551787474, 0.03160167988, 0.08315031015, 0.1295143636, 0.1295143636, 0.08315031015, 0.03160167988, 0.00551787474, 0.0001309279731, 0.000140535927, },
{1.102280392e-05, 0.001356012537, 0.01499414005, 0.05525973093, 0.1099887688, 0.1366692652, 0.1099887688, 0.05525973093, 0.01499414005, 0.001356012537, 1.102280392e-05, 0, },
};
static float i_hist[PHASES][COEFFS] = {};
static float q_hist[PHASES][COEFFS] = {};
static FIRF_FILTER fir[2][PHASES] =
{
{
// i/q phase
{.length = COEFFS, .b = b[1], .hist = i_hist[0]}, // 0 0
{.length = COEFFS, .b = b[0], .hist = i_hist[1]} // 0 1
},
{
// i/q phase
{.length = COEFFS, .b = b[1], .hist = q_hist[0]}, // 1 0
{.length = COEFFS, .b = b[0], .hist = q_hist[1]} // 1 1
},
};
static PPF_FILTER filter[2] =
{
{.sum = 0, .phase = 0, .max_phase = PHASES, .fir = fir[0]}, // 0 =: i
{.sum = 0, .phase = 0, .max_phase = PHASES, .fir = fir[1]}, // 1 =: q
};
#undef COEFFS
#undef PHASES
return ppf(sample, &filter[i_or_q]);
}
static inline float lp_ppffp_butter_1600kHz_160kHz_200kHz(int sample, size_t i_or_q)
{
#define PHASES 2
#define COEFFS 12
static const fixedpt b[PHASES][COEFFS] =
{
{fixedpt_rconst(0.000140535927), fixedpt_rconst(0.0001309279731), fixedpt_rconst(0.00551787474), fixedpt_rconst(0.03160167988), fixedpt_rconst(0.08315031015), fixedpt_rconst(0.1295143636), fixedpt_rconst(0.1295143636), fixedpt_rconst(0.08315031015), fixedpt_rconst(0.03160167988), fixedpt_rconst(0.00551787474), fixedpt_rconst(0.0001309279731), fixedpt_rconst(0.000140535927), },
{fixedpt_rconst(1.102280392e-05), fixedpt_rconst(0.001356012537), fixedpt_rconst(0.01499414005), fixedpt_rconst(0.05525973093), fixedpt_rconst(0.1099887688), fixedpt_rconst(0.1366692652), fixedpt_rconst(0.1099887688), fixedpt_rconst(0.05525973093), fixedpt_rconst(0.01499414005), fixedpt_rconst(0.001356012537), fixedpt_rconst(1.102280392e-05), fixedpt_rconst(0), },
};
static fixedpt i_hist[PHASES][COEFFS] = {};
static fixedpt q_hist[PHASES][COEFFS] = {};
static FIRFP_FILTER fir[2][PHASES] =
{
{
// i/q phase
{.length = COEFFS, .b = b[1], .hist = i_hist[0]}, // 0 0
{.length = COEFFS, .b = b[0], .hist = i_hist[1]} // 0 1
},
{
// i/q phase
{.length = COEFFS, .b = b[1], .hist = q_hist[0]}, // 1 0
{.length = COEFFS, .b = b[0], .hist = q_hist[1]} // 1 1
},
};
static PPFFP_FILTER filter[2] =
{
{.sum = fixedpt_rconst(0), .phase = 0, .max_phase = PHASES, .fir = fir[0]}, // 0 =: i
{.sum = fixedpt_rconst(0), .phase = 0, .max_phase = PHASES, .fir = fir[1]}, // 1 =: q
};
#undef COEFFS
#undef PHASES
return fixedpt_tofloat(ppffp(fixedpt_fromint(sample), &filter[i_or_q]));
}
static inline float bp_iir_cheb1_800kHz_90kHz_98kHz_102kHz_110kHz(float sample)
{
#define GAIN 1.874981046e-06
#define SECTIONS 3
static const float b[3*SECTIONS] = {1, 1.999994649, 0.9999946492, 1, -1.99999482, 0.9999948196, 1, 1.703868036e-07, -1.000010531, };
static const float a[3*SECTIONS] = {1, -1.387139203, 0.9921518712, 1, -1.403492665, 0.9845934971, 1, -1.430055639, 0.9923856172, };
static float hist[3*SECTIONS] = {};
static IIRF_FILTER filter = {.sections = SECTIONS, .b = b, .a = a, .gain = GAIN, .hist = hist};
#undef SECTIONS
#undef GAIN
return iirf(sample, &filter);
}
static inline float lp_fir_butter_800kHz_100kHz_10kHz(float sample)
{
#define COEFFS 4
static const float b[COEFFS] = {0.04421550009, 0.4557844999, 0.4557844999, 0.04421550009, };
static float hist[COEFFS];
static FIRF_FILTER filter = {.length = COEFFS, .b = b, .hist = hist};
#undef COEFFS
return firf(sample, &filter);
}
static float rssi_filter(int sample)
{
static float old_sample;
#define ALPHA 0.6789f
old_sample = ALPHA*sample + (1.0f - ALPHA)*old_sample;
#undef ALPHA
return old_sample;
}
static inline float polar_discriminator(float i, float q)
{
static float complex s_last;
const float complex s = i + q * _Complex_I;
const float complex y = s * conj(s_last);
#if 0
const float delta_phi = atan2_libm(y);
#elif 1
const float delta_phi = atan2_approximation(y);
#else
const float delta_phi = atan2_approximation2(y);
#endif
s_last = s;
return delta_phi;
}
/** @brief Sparse Ones runs in time proportional to the number
* of 1 bits.
*
* From: http://gurmeet.net/puzzles/fast-bit-counting-routines
*/
static inline unsigned count_set_bits_sparse_one(uint32_t n)
{
unsigned count = 0;
while (n)
{
count++;
n &= (n - 1) ; // set rightmost 1 bit in n to 0
}
return count;
}
static inline unsigned count_set_bits(uint32_t n)
{
#if defined(__i386__) || defined(__arm__)
return __builtin_popcount(n);
#else
return count_set_bits_sparse_one(n);
#endif
}
static inline int majority_votes_bitfilter(uint32_t unfilt_bitstream, uint32_t bits_in_unfilt_bitstream)
{
const unsigned ones = count_set_bits(unfilt_bitstream & bits_in_unfilt_bitstream);
const bool odd = (ones & 1) > 0;
const uint32_t bits_in_unfilt_bitstream_half = count_set_bits(bits_in_unfilt_bitstream)/2;
if (odd)
return (ones <= bits_in_unfilt_bitstream_half) ? 0 : 1;
if (ones < bits_in_unfilt_bitstream_half)
return 0;
if (ones > bits_in_unfilt_bitstream_half)
return 1;
return unfilt_bitstream & 1;
}
typedef void (*OutFunction)(unsigned bit, unsigned rssi);
static inline void to_stdout(unsigned bit, unsigned rssi)
{
(void)rssi;
const uint8_t tmp = bit;
fwrite(&tmp, sizeof(tmp), 1, stdout);
}
static const OutFunction out_functions[] = { to_stdout, t1_c1_packet_decoder };
int main(int argc, char *argv[])
{
(void)argc;
(void)argv;
// --- parameter section begin ---
// The idea behind the variables in the section is to make parameters
// configurable via command line.
const unsigned CLOCK_LOCK_THRESHOLD = 2;
const unsigned DECIMATION_RATE = 2;
//#define USING_BITFILTER
const uint32_t ACCESS_CODE = 0b0101010101010000111101u;
const uint32_t ACCESS_CODE_BITMASK = 0x3FFFFFu;
const unsigned ACCESS_CODE_ERRORS = 1u; // 0 if no errors allowed
// --- parameter section end ---
// Select function for output
OutFunction out_function = out_functions[1];
__attribute__((__aligned__(16))) uint8_t samples[4096];
float i = 0, q = 0;
unsigned decimation_rate_index = 0;
int16_t old_clock = INT16_MIN;
uint32_t bitstream = 0;
unsigned clock_lock = 0;
#if defined(USING_BITFILTER)
uint32_t unfilt_bitstream = 0;
uint32_t bits_in_unfilt_bitstream = 0;
#endif
#if defined (__SSE4_2__)
__attribute__((__aligned__(16))) int16_t iq_samples[sizeof(samples)];
const __m128i dc_offset = _mm_set_epi16(-127, -127, -127, -127, -127, -127, -127, -127);
#endif
//FILE *input = fopen("samples.bin", "rb");
//FILE *input = get_net("localhost", 14423);
FILE *input= stdin;
if (input == NULL)
{
fprintf(stderr, "opening input error\n");
return EXIT_FAILURE;
}
//FILE *demod_out = fopen("demod.bin", "wb");
//FILE *demod_out2 = fopen("demod.bin", "wb");
//FILE *clock_out = fopen("clock.bin", "wb");
//FILE *bits_out= fopen("bits.bin", "wb");
while (!feof(input))
{
size_t read_items = fread(samples, sizeof(samples), 1, input);
if (1 != read_items)
{
// End of file?..
return 2;
}
#if defined (__SSE4_2__)
for (size_t k = 0; k < sizeof(samples)/sizeof(samples[0]); k += 8) // +2 : i and q interleaved
{
__m128i tmp = _mm_loadu_si128((__m128i const*)&samples[k]); // Hmmm, loading 8 byte besides of upper boundary?..
__m128i cvt = _mm_add_epi16(_mm_cvtepu8_epi16(tmp), dc_offset);
_mm_store_si128((__m128i *)&iq_samples[k], cvt);
}
#endif
for (size_t k = 0; k < sizeof(samples)/sizeof(samples[0]); k += 2) // +2 : i and q interleaved
{
#if defined (__SSE4_2__)
const int i_unfilt = iq_samples[k];
const int q_unfilt = iq_samples[k+1];
#else
const int i_unfilt = ((int)samples[k] - 127);
const int q_unfilt = ((int)samples[k + 1] - 127);
#endif
// Low-Pass-Filtering before decimation is necessary, to ensure
// that i and q signals don't contain frequencies above new sample
// rate.
// The sample rate decimation is realised as sum over i and q,
// which must not be divided by decimation factor before
// demodulating (atan2(q,i)).
#if 0
i = lp_fir_butter_1600kHz_160kHz_200kHz(i_unfilt, 0);
q = lp_fir_butter_1600kHz_160kHz_200kHz(q_unfilt, 1);
#elif 0
i = lp_ppf_butter_1600kHz_160kHz_200kHz(i_unfilt, 0);
q = lp_ppf_butter_1600kHz_160kHz_200kHz(q_unfilt, 1);
#elif 0
i = lp_firfp_butter_1600kHz_160kHz_200kHz(i_unfilt, 0);
q = lp_firfp_butter_1600kHz_160kHz_200kHz(q_unfilt, 1);
#elif 0
i = lp_ppffp_butter_1600kHz_160kHz_200kHz(i_unfilt, 0);
q = lp_ppffp_butter_1600kHz_160kHz_200kHz(q_unfilt, 1);
#elif 0
i += lp_1600kHz_58kHz(i_unfilt, 0);
q += lp_1600kHz_58kHz(q_unfilt, 1);
#define USE_MOVING_AVERAGE
#else
i += moving_average(i_unfilt, 0);
q += moving_average(q_unfilt, 1);
#define USE_MOVING_AVERAGE
#endif
++decimation_rate_index;
if (decimation_rate_index < DECIMATION_RATE) continue;
decimation_rate_index = 0;
// Demodulate.
float delta_phi = polar_discriminator(i, q);
//int16_t demodulated_signal = (INT16_MAX-1)*delta_phi;
//fwrite(&demodulated_signal, sizeof(demodulated_signal), 1, demod_out);
// Post-filtering to prevent bit errors because of signal jitter.
delta_phi = lp_fir_butter_800kHz_100kHz_10kHz(delta_phi);
//int16_t demodulated_signal = (INT16_MAX-1)*delta_phi;
//fwrite(&demodulated_signal, sizeof(demodulated_signal), 1, demod_out2);
// --- clock recovery section begin ---
// The time-2 method is implemented: push squared signal through a bandpass
// tuned close to the symbol rate. Saturating band-pass output produces a
// rectangular pulses with the required timing information.
// Clock-Signal is crossing zero in half period.
const int16_t clock = (bp_iir_cheb1_800kHz_90kHz_98kHz_102kHz_110kHz(delta_phi * delta_phi) >= 0) ? INT16_MAX : INT16_MIN;
//fwrite(&clock, sizeof(clock), 1, clock_out);
unsigned bit = (delta_phi >= 0) ? (1u<<PACKET_DATABIT_SHIFT) : (0u<<PACKET_DATABIT_SHIFT);
#if defined(USING_BITFILTER)
unfilt_bitstream = (unfilt_bitstream << 1) | bit;
bits_in_unfilt_bitstream = (bits_in_unfilt_bitstream << 1) | 1;
#endif
// We are using one simple filter to rssi value in order to
// prevent unexpected "splashes" in signal power.
float rssi = sqrtf(i*i + q*q);
rssi = rssi_filter(rssi); // comment out, if rssi filtering is unwanted
if (clock > old_clock) // rising edge
{
clock_lock = 1;
#if defined(USING_BITFILTER)
unfilt_bitstream = bit;
bits_in_unfilt_bitstream = 1;
#endif
}
else if (old_clock == clock && clock_lock < CLOCK_LOCK_THRESHOLD)
{
clock_lock++;
}
else if (clock_lock == CLOCK_LOCK_THRESHOLD) // sample data bit on CLOCK_LOCK_THRESHOLD after rose up
{
clock_lock++;
#if defined(USE_MOVING_AVERAGE)
// If using moving average, we would habe doubles of each of i- and q- signal components.
rssi /= DECIMATION_RATE;
#endif
#if defined(USING_BITFILTER)
// Bitfilter can be used to remove unwanted spikes in the demodulated signal.
bit = majority_votes_bitfilter(unfilt_bitstream, bits_in_unfilt_bitstream);
#endif
bitstream = (bitstream << 1) | bit;
if (count_set_bits((bitstream & ACCESS_CODE_BITMASK) ^ ACCESS_CODE) <= ACCESS_CODE_ERRORS)
{
bit |= (1u<<PACKET_PREAMBLE_DETECTED_SHIFT); // packet detected; mark the bit similar to "Access Code"-Block in GNU Radio
}
//fwrite(&bit, sizeof(bit), 1, bits_out);
out_function(bit, rssi);
}
old_clock = clock;
// --- clock recovery section end ---
#if defined(USE_MOVING_AVERAGE)
i = q = 0;
#endif
}
}
return EXIT_SUCCESS;
}
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