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srsLTE
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srsLTE/srslte/lib/fec/test/turbodecoder_test.c

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/**
*
* \section COPYRIGHT
*
* Copyright 2013-2015 The srsLTE Developers. See the
* COPYRIGHT file at the top-level directory of this distribution.
*
* \section LICENSE
*
* This file is part of the srsLTE library.
*
* srsLTE is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of
* the License, or (at your option) any later version.
*
* srsLTE 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 Affero General Public License for more details.
*
* A copy of the GNU Affero General Public License can be found in
* the LICENSE file in the top-level directory of this distribution
* and at http://www.gnu.org/licenses/.
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <unistd.h>
#include <math.h>
#include <time.h>
#include <sys/time.h>
#include <time.h>
#include "srslte/srslte.h"
#include "turbodecoder_test.h"
uint32_t frame_length = 1000, nof_frames = 100;
float ebno_db = 100.0;
uint32_t seed = 0;
int K = -1;
#define MAX_ITERATIONS 4
int nof_iterations = MAX_ITERATIONS;
int test_known_data = 0;
int test_errors = 0;
#define SNR_POINTS 8
#define SNR_MIN 0.0
#define SNR_MAX 4.0
void usage(char *prog) {
printf("Usage: %s [nlesv]\n", prog);
printf(
"\t-k Test with known data (ignores frame_length) [Default disabled]\n");
printf("\t-i nof_iterations [Default %d]\n", nof_iterations);
printf("\t-n nof_frames [Default %d]\n", nof_frames);
printf("\t-l frame_length [Default %d]\n", frame_length);
printf("\t-e ebno in dB [Default scan]\n");
printf("\t-t test: check errors on exit [Default disabled]\n");
printf("\t-s seed [Default 0=time]\n");
}
void parse_args(int argc, char **argv) {
int opt;
while ((opt = getopt(argc, argv, "inlstvekt")) != -1) {
switch (opt) {
case 'n':
nof_frames = atoi(argv[optind]);
break;
case 'k':
test_known_data = 1;
break;
case 't':
test_errors = 1;
break;
case 'i':
nof_iterations = atoi(argv[optind]);
break;
case 'l':
frame_length = atoi(argv[optind]);
break;
case 'e':
ebno_db = atof(argv[optind]);
break;
case 's':
seed = (uint32_t) strtoul(argv[optind], NULL, 0);
break;
case 'v':
srslte_verbose++;
break;
default:
usage(argv[0]);
exit(-1);
}
}
}
void output_matlab(float ber[MAX_ITERATIONS][SNR_POINTS], int snr_points) {
int i, j;
FILE *f = fopen("turbocoder_snr.m", "w");
if (!f) {
perror("fopen");
exit(-1);
}
fprintf(f, "ber=[");
for (j = 0; j < MAX_ITERATIONS; j++) {
for (i = 0; i < snr_points; i++) {
fprintf(f, "%g ", ber[j][i]);
}
fprintf(f, ";\n");
}
fprintf(f, "];\n");
fprintf(f, "snr=linspace(%g,%g-%g/%d,%d);\n", SNR_MIN, SNR_MAX, SNR_MAX,
snr_points, snr_points);
fprintf(f, "semilogy(snr,ber,snr,0.5*erfc(sqrt(10.^(snr/10))));\n");
fprintf(f,
"legend('1 iter','2 iter', '3 iter', '4 iter', 'theory-uncoded');");
fprintf(f, "grid on;\n");
fclose(f);
}
int main(int argc, char **argv) {
uint32_t frame_cnt;
float *llr;
uint8_t *llr_c;
uint8_t *data_tx, *data_rx, *symbols;
uint32_t i, j;
float var[SNR_POINTS];
uint32_t snr_points;
float ber[MAX_ITERATIONS][SNR_POINTS];
uint32_t errors[100];
uint32_t coded_length;
struct timeval tdata[3];
float mean_usec;
srslte_tdec_t tdec;
srslte_tcod_t tcod;
parse_args(argc, argv);
if (!seed) {
seed = time(NULL);
}
srand(seed);
if (test_known_data) {
frame_length = KNOWN_DATA_LEN;
} else {
frame_length = srslte_cbsegm_cbsize(srslte_cbsegm_cbindex(frame_length));
}
coded_length = 3 * (frame_length) + SRSLTE_TCOD_TOTALTAIL;
printf(" Frame length: %d\n", frame_length);
if (ebno_db < 100.0) {
printf(" EbNo: %.2f\n", ebno_db);
}
data_tx = srslte_vec_malloc(frame_length * sizeof(uint8_t));
if (!data_tx) {
perror("malloc");
exit(-1);
}
data_rx = srslte_vec_malloc(frame_length * sizeof(uint8_t));
if (!data_rx) {
perror("malloc");
exit(-1);
}
symbols = srslte_vec_malloc(coded_length * sizeof(uint8_t));
if (!symbols) {
perror("malloc");
exit(-1);
}
llr = srslte_vec_malloc(coded_length * sizeof(float));
if (!llr) {
perror("malloc");
exit(-1);
}
llr_c = srslte_vec_malloc(coded_length * sizeof(uint8_t));
if (!llr_c) {
perror("malloc");
exit(-1);
}
if (srslte_tcod_init(&tcod, frame_length)) {
fprintf(stderr, "Error initiating Turbo coder\n");
exit(-1);
}
if (srslte_tdec_init(&tdec, frame_length)) {
fprintf(stderr, "Error initiating Turbo decoder\n");
exit(-1);
}
float ebno_inc, esno_db;
ebno_inc = (SNR_MAX - SNR_MIN) / SNR_POINTS;
if (ebno_db == 100.0) {
snr_points = SNR_POINTS;
for (i = 0; i < snr_points; i++) {
ebno_db = SNR_MIN + i * ebno_inc;
esno_db = ebno_db + 10 * log10((double) 1 / 3);
var[i] = sqrt(1 / (pow(10, esno_db / 10)));
}
} else {
esno_db = ebno_db + 10 * log10((double) 1 / 3);
var[0] = sqrt(1 / (pow(10, esno_db / 10)));
snr_points = 1;
}
for (i = 0; i < snr_points; i++) {
mean_usec = 0;
frame_cnt = 0;
bzero(errors, sizeof(int) * MAX_ITERATIONS);
while (frame_cnt < nof_frames) {
/* generate data_tx */
for (j = 0; j < frame_length; j++) {
if (test_known_data) {
data_tx[j] = known_data[j];
} else {
data_tx[j] = rand() % 2;
}
}
/* coded BER */
if (test_known_data) {
for (j = 0; j < coded_length; j++) {
symbols[j] = known_data_encoded[j];
}
} else {
srslte_tcod_encode(&tcod, data_tx, symbols, frame_length);
}
for (j = 0; j < coded_length; j++) {
llr[j] = symbols[j] ? sqrt(2) : -sqrt(2);
}
srslte_ch_awgn_f(llr, llr, var[i], coded_length);
/* decoder */
srslte_tdec_reset(&tdec, frame_length);
uint32_t t;
if (nof_iterations == -1) {
t = MAX_ITERATIONS;
} else {
t = nof_iterations;
}
for (j = 0; j < t; j++) {
if (!j)
gettimeofday(&tdata[1], NULL); // Only measure 1 iteration
srslte_tdec_iteration(&tdec, llr, frame_length);
srslte_tdec_decision(&tdec, data_rx, frame_length);
if (!j)
gettimeofday(&tdata[2], NULL);
if (!j)
get_time_interval(tdata);
if (!j)
mean_usec = (float) mean_usec * 0.9 + (float) tdata[0].tv_usec * 0.1;
/* check errors */
errors[j] += srslte_bit_diff(data_tx, data_rx, frame_length);
if (j < MAX_ITERATIONS) {
ber[j][i] = (float) errors[j] / (frame_cnt * frame_length);
}
}
frame_cnt++;
printf("Eb/No: %3.2f %10d/%d ",
SNR_MIN + i * ebno_inc, frame_cnt, nof_frames);
printf("BER: %.2e ", (float) errors[j - 1] / (frame_cnt * frame_length));
printf("%3.1f Mbps (%6.2f usec)", (float) frame_length / mean_usec,
mean_usec);
printf("\r");
}
printf("\n");
if (snr_points == 1) {
if (test_known_data && seed == KNOWN_DATA_SEED
&& ebno_db == KNOWN_DATA_EBNO && frame_cnt == KNOWN_DATA_NFRAMES) {
for (j = 0; j < MAX_ITERATIONS; j++) {
if (errors[j] > known_data_errors[j]) {
fprintf(stderr, "Expected %d errors but got %d\n",
known_data_errors[j], errors[j]);
exit(-1);
} else {
printf("Iter %d ok\n", j + 1);
}
}
} else {
for (j = 0; j < MAX_ITERATIONS; j++) {
printf("BER: %g\t%u errors\n",
(float) errors[j] / (frame_cnt * frame_length), errors[j]);
if (test_errors) {
if (errors[j]
> get_expected_errors(frame_cnt, seed, j + 1, frame_length,
ebno_db)) {
fprintf(stderr, "Expected %d errors but got %d\n",
get_expected_errors(frame_cnt, seed, j + 1, frame_length,
ebno_db), errors[j]);
exit(-1);
} else {
printf("Iter %d ok\n", j + 1);
}
}
}
}
}
}
free(data_tx);
free(symbols);
free(llr);
free(llr_c);
free(data_rx);
srslte_tdec_free(&tdec);
srslte_tcod_free(&tcod);
printf("\n");
output_matlab(ber, snr_points);
printf("Done\n");
exit(0);
}
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