import some gsm band/arfcn/time related utilities from OsmocomBB

This commit is contained in:
Harald Welte 2010-03-07 17:50:21 +01:00
parent 63d3e396e7
commit 622b718195
2 changed files with 114 additions and 1 deletions

View File

@ -27,6 +27,14 @@
#include <stdint.h>
struct gsm_time {
uint32_t fn; /* FN count */
uint16_t t1; /* FN div (26*51) */
uint8_t t2; /* FN modulo 26 */
uint8_t t3; /* FN modulo 51 */
uint8_t tc;
};
enum gsm_band {
GSM_BAND_850 = 1,
GSM_BAND_900 = 2,
@ -58,5 +66,19 @@ static inline int rach_max_trans_raw2val(int raw) {
return tbl[raw & 3];
}
#define ARFCN_PCS 0x8000
#define ARFCN_UPLINK 0x4000
enum gsm_band gsm_arfcn2band(uint16_t arfcn);
/* Convert an ARFCN to the frequency in MHz * 10 */
uint16_t gsm_arfcn2freq10(uint16_t arfcn, int uplink);
/* Convert from frame number to GSM time */
void gsm_fn2gsmtime(struct gsm_time *time, uint32_t fn);
/* Convert from GSM time to frame number */
uint32_t gsm_gsmtime2fn(struct gsm_time *time);
void generate_backtrace();
#endif

View File

@ -1,7 +1,7 @@
/*
* (C) 2008 by Daniel Willmann <daniel@totalueberwachung.de>
* (C) 2009 by Holger Hans Peter Freyther <zecke@selfish.org>
* (C) 2009 by Harald Welte <laforge@gnumonks.org>
* (C) 2009-2010 by Harald Welte <laforge@gnumonks.org>
*
* All Rights Reserved
*
@ -268,3 +268,94 @@ void generate_backtrace()
free(strings);
}
#endif
enum gsm_band gsm_arfcn2band(uint16_t arfcn)
{
if (arfcn & ARFCN_PCS)
return GSM_BAND_1900;
else if (arfcn <= 124)
return GSM_BAND_900;
else if (arfcn >= 955 && arfcn <= 1023)
return GSM_BAND_900;
else if (arfcn >= 128 && arfcn <= 251)
return GSM_BAND_850;
else if (arfcn >= 512 && arfcn <= 885)
return GSM_BAND_1800;
else if (arfcn >= 259 && arfcn <= 293)
return GSM_BAND_450;
else if (arfcn >= 306 && arfcn <= 340)
return GSM_BAND_480;
else if (arfcn >= 350 && arfcn <= 425)
return GSM_BAND_810;
else if (arfcn >= 438 && arfcn <= 511)
return GSM_BAND_750;
else
return GSM_BAND_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));
}