Estoy interesado en encontrar la matriz generadora utilizada para la codificación del canal TCH3 ( GEO -Interfaz de radio móvil ). Seguí los pasos de instalación indicados en OsmocomGMR . Hubo un ejemplo para que el canal FACCH3 generara la matriz G. Modifiqué el código para TCH3 (que se muestra a continuación) pero los resultados de salida no parecen correctos. Realmente lo agradecería si pudiera decirme qué está haciendo mal en el código a continuación.
Gracias de antemano.
/* GMR-1 G/g matrix geneation forTCH3 */
/* (C) 2011 by Sylvain Munaut <[email protected]> * All Rights Reserved
* * This program 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. * * 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 Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <osmocom/core/bits.h>
#include <osmocom/core/utils.h>
#include <osmocom/gmr1/l1/tch3.h>
static void copy_bits(ubit_t *dst, int r, ubit_t *bits_e) { int i, j
= 0; for(i=0;i<212;i++){ if (i<52 || i > 55){ dst[(208*r)+j] = bits_e[i]; j++; } }
}
static int pbm_save_bits(const char *filename, ubit_t *m, int x, int y) { FILE *fh; int i, j;
fh = fopen(filename, "w"); if (!fh) return -EPERM;
fprintf(fh, "P1\n%d %d\n", x, y);
for (i=0; i<y; i++) for (j=0; j<x; j++) fprintf(fh, "%d%c", m[(i*x)+j], j==x-1 ? '\n' : ' ');
fclose(fh);
return 0; }
int main(int argc, char *argv[]) {
ubit_t mat_G[208*160]; /* 208 lines of 160 pixels */ ubit_t mat_g[208]; /* 208 lines of 1 pixel */
ubit_t bits_e[212]; ubit_t bits_u1[160]; ubit_t bits_s[4]; uint8_t l1[10]; uint8_t l2[10];
int i; int j; int m = 0;
memset(mat_G, 0x00, sizeof(mat_G)); memset(mat_g, 0x00, sizeof(mat_g));
memset(bits_s, 0x00, sizeof(bits_s)); memset(l1, 0x00, sizeof(l1)); memset(l2, 0x00, sizeof(l2));
gmr1_tch3_encode(bits_e, l1, l2, bits_s, NULL,m); copy_bits(mat_g, 0, bits_e);
for (i=0; i<160; i++) { memset(l1, 0x00, sizeof(l1)); memset(l2, 0x00, sizeof(l2)); memset(bits_u1, 0, sizeof(bits_u1)); bits_u1[i] = 1;
osmo_ubit2pbit_ext(l1, 0, bits_u1, 0, 80, 1); osmo_ubit2pbit_ext(l2, 0, bits_u1, 80, 80, 1);
gmr1_tch3_encode(bits_e, l1, l2, bits_s, NULL,m); copy_bits(mat_G, i, bits_e);
} for (i=0; i<160; i++) { for (j=0; j<208; j++) { mat_G[(i*208)+j] ^= mat_g[j]; } }
pbm_save_bits("mat_G.pbm", mat_G, 160, 208); pbm_save_bits("mat_g.pbm", mat_g, 1, 208); printf("\n"); }