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Diffstat (limited to 'src/target/firmware/layer1/gsm.c')
| -rw-r--r-- | src/target/firmware/layer1/gsm.c | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/src/target/firmware/layer1/gsm.c b/src/target/firmware/layer1/gsm.c new file mode 100644 index 00000000..99f67f30 --- /dev/null +++ b/src/target/firmware/layer1/gsm.c @@ -0,0 +1,117 @@ +/* Generic GSM utility routines */ + +/* (C) 2010 by Harald Welte <laforge@gnumonks.org> + * + * All Rights Reserved + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + * + */ + + +#include <stdint.h> + +#include <gsm.h> + +enum gsm_band gsm_arfcn2band(uint16_t arfcn) +{ + if (arfcn & ARFCN_PCS) + return GSM_1900; + else if (arfcn <= 124) + return GSM_900; + else if (arfcn >= 955 && arfcn <= 1023) + return GSM_900; + else if (arfcn >= 128 && arfcn <= 251) + return GSM_850; + else if (arfcn >= 512 && arfcn <= 885) + return GSM_1800; + else if (arfcn >= 259 && arfcn <= 293) + return GSM_450; + else if (arfcn >= 306 && arfcn <= 340) + return GSM_480; + else if (arfcn >= 350 && arfcn <= 425) + return GSM_810; + else if (arfcn >= 438 && arfcn <= 511) + return GSM_750; + else + return GSM_1800; +} + +/* Convert an ARFCN to the frequency in MHz * 10 */ +uint16_t gsm_arfcn2freq10(uint16_t arfcn, int uplink) +{ + uint16_t freq10_ul; + uint16_t freq10_dl; + + if (arfcn & ARFCN_PCS) { + /* DCS 1900 */ + arfcn &= ~ARFCN_PCS; + freq10_ul = 18502 + 2 * (arfcn-512); + freq10_dl = freq10_ul + 800; + } else if (arfcn <= 124) { + /* Primary GSM + ARFCN 0 of E-GSM */ + freq10_ul = 8900 + 2 * arfcn; + freq10_dl = freq10_ul + 450; + } else if (arfcn >= 955 && arfcn <= 1023) { + /* E-GSM and R-GSM */ + freq10_ul = 8900 + 2 * (arfcn - 1024); + freq10_dl = freq10_ul + 450; + } else if (arfcn >= 128 && arfcn <= 251) { + /* GSM 850 */ + freq10_ul = 8242 + 2 * (arfcn - 128); + freq10_dl = freq10_ul + 450; + } else if (arfcn >= 512 && arfcn <= 885) { + /* DCS 1800 */ + freq10_ul = 17102 + 2 * (arfcn - 512); + freq10_dl = freq10_ul + 950; + } else if (arfcn >= 259 && arfcn <= 293) { + /* GSM 450 */ + freq10_ul = 4506 + 2 * (arfcn - 259); + freq10_dl = freq10_ul + 100; + } else if (arfcn >= 306 && arfcn <= 340) { + /* GSM 480 */ + freq10_ul = 4790 + 2 * (arfcn - 306); + freq10_dl = freq10_ul + 100; + } else if (arfcn >= 350 && arfcn <= 425) { + /* GSM 810 */ + freq10_ul = 8060 + 2 * (arfcn - 350); + freq10_dl = freq10_ul + 450; + } else if (arfcn >= 438 && arfcn <= 511) { + /* GSM 750 */ + freq10_ul = 7472 + 2 * (arfcn - 438); + freq10_dl = freq10_ul + 300; + } else + return 0xffff; + + if (uplink) + return freq10_ul; + else + return freq10_dl; +} + +void gsm_fn2gsmtime(struct gsm_time *time, uint32_t fn) +{ + time->fn = fn; + time->t1 = time->fn / (26*51); + time->t2 = time->fn % 26; + time->t3 = time->fn % 51; + time->tc = (time->fn / 51) % 8; +} + +uint32_t gsm_gsmtime2fn(struct gsm_time *time) +{ + /* TS 05.02 Chapter 4.3.3 TDMA frame number */ + return (51 * ((time->t3 - time->t2 + 26) % 26) + time->t3 + (26 * 51 * time->t1)); +} |