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

[osmocom-bb.git] / src / gsm_utils.c

diff --git a/src/gsm_utils.c b/src/gsm_utils.c
index 174b2d4..4ee137c 100644 (file)
--- a/src/gsm_utils.c
+++ b/src/gsm_utils.c
@@ -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));
+}