118 lines
3.2 KiB
C
118 lines
3.2 KiB
C
/* Generic GSM utility routines */
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/* (C) 2010 by Harald Welte <laforge@gnumonks.org>
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*
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* All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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*/
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#include <stdint.h>
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#include <gsm.h>
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enum gsm_band gsm_arfcn2band(uint16_t arfcn)
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{
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if (arfcn & ARFCN_PCS)
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return GSM_1900;
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else if (arfcn <= 124)
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return GSM_900;
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else if (arfcn >= 955 && arfcn <= 1023)
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return GSM_900;
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else if (arfcn >= 128 && arfcn <= 251)
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return GSM_850;
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else if (arfcn >= 512 && arfcn <= 885)
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return GSM_1800;
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else if (arfcn >= 259 && arfcn <= 293)
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return GSM_450;
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else if (arfcn >= 306 && arfcn <= 340)
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return GSM_480;
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else if (arfcn >= 350 && arfcn <= 425)
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return GSM_810;
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else if (arfcn >= 438 && arfcn <= 511)
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return GSM_750;
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else
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return GSM_1800;
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}
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/* Convert an ARFCN to the frequency in MHz * 10 */
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uint16_t gsm_arfcn2freq10(uint16_t arfcn, int uplink)
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{
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uint16_t freq10_ul;
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uint16_t freq10_dl;
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if (arfcn & ARFCN_PCS) {
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/* DCS 1900 */
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arfcn &= ~ARFCN_PCS;
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freq10_ul = 18502 + 2 * (arfcn-512);
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freq10_dl = freq10_ul + 800;
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} else if (arfcn <= 124) {
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/* Primary GSM + ARFCN 0 of E-GSM */
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freq10_ul = 8900 + 2 * arfcn;
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freq10_dl = freq10_ul + 450;
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} else if (arfcn >= 955 && arfcn <= 1023) {
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/* E-GSM and R-GSM */
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freq10_ul = 8900 + 2 * (arfcn - 1024);
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freq10_dl = freq10_ul + 450;
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} else if (arfcn >= 128 && arfcn <= 251) {
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/* GSM 850 */
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freq10_ul = 8242 + 2 * (arfcn - 128);
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freq10_dl = freq10_ul + 450;
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} else if (arfcn >= 512 && arfcn <= 885) {
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/* DCS 1800 */
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freq10_ul = 17102 + 2 * (arfcn - 512);
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freq10_dl = freq10_ul + 950;
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} else if (arfcn >= 259 && arfcn <= 293) {
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/* GSM 450 */
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freq10_ul = 4506 + 2 * (arfcn - 259);
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freq10_dl = freq10_ul + 100;
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} else if (arfcn >= 306 && arfcn <= 340) {
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/* GSM 480 */
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freq10_ul = 4790 + 2 * (arfcn - 306);
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freq10_dl = freq10_ul + 100;
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} else if (arfcn >= 350 && arfcn <= 425) {
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/* GSM 810 */
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freq10_ul = 8060 + 2 * (arfcn - 350);
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freq10_dl = freq10_ul + 450;
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} else if (arfcn >= 438 && arfcn <= 511) {
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/* GSM 750 */
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freq10_ul = 7472 + 2 * (arfcn - 438);
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freq10_dl = freq10_ul + 300;
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} else
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return 0xffff;
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if (uplink)
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return freq10_ul;
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else
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return freq10_dl;
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}
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void gsm_fn2gsmtime(struct gsm_time *time, uint32_t fn)
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{
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time->fn = fn;
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time->t1 = time->fn / (26*51);
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time->t2 = time->fn % 26;
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time->t3 = time->fn % 51;
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time->tc = (time->fn / 51) % 8;
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}
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uint32_t gsm_gsmtime2fn(struct gsm_time *time)
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{
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/* TS 05.02 Chapter 4.3.3 TDMA frame number */
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return (51 * ((time->t3 - time->t2 + 26) % 26) + time->t3 + (26 * 51 * time->t1));
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}
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