gmr December 2018

gmr@lists.osmocom.org

2 participants
2 discussions

OsmoDevCon 2019 registration
by Harald Welte 01 Jan '19

01 Jan '19

Dear fellow Osmocom developers, I'm a bit surprised to notice that not more people have signed up for OsmoDevCon 2019. I guess it was mostly an oversight when the date was originally announced, and not a lack of interest? ;) All details about the event are available at the related wiki page at: https://osmocom.org/projects/osmo-dev-con/wiki/OsmoDevCon2019 Please enter your name at https://osmocom.org/projects/osmo-dev-con/wiki/OsmoDevCon2019#Requested in case you would like to attend. Registering early allows proper planning. Thanks! Looking forward to meeting old and new Osmocom developers in April 2019. Regards, Harald -- - Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/ ============================================================================ "Privacy in residential applications is a desirable marketing option." (ETSI EN 300 175-7 Ch. A6)

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Generator matrix used for TCH3 channel encoding
by wireless gmr 17 Dec '18

17 Dec '18

I am interested in finding the generator matrix used for TCH3 channel encoding (GEO-Mobile Radio Interface). I followed the installation steps indicated in OsmocomGMR. There was an example for FACCH3 channel to generate the G matrix. I modified the code for TCH3 (shown below) but the output results does not seems correct. I would really appreciate it if you can tell me what I am doing wrong in the code below. /* GMR-1 G/g matrix geneation forTCH3 */ /* (C) 2011 by Sylvain Munaut <tnt(a)246tNt.com> * 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"); }

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gmr December 2018