1 files changed, 87 insertions, 0 deletions
diff --git a/src/osmo-bts-sysmo/utils.c b/src/osmo-bts-sysmo/utils.c
new file mode 100644
index 00000000..d3ee872c
--- /dev/null
+++ b/src/osmo-bts-sysmo/utils.c
@@ -0,0 +1,87 @@
+/*
+ * Helper utilities that are used in OML
+ *
+ * (C) 2011 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2013 by Holger Hans Peter Freyther
+ *
+ * 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 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 "utils.h"
+
+#include <osmo-bts/bts.h>
+
+#include "femtobts.h"
+
+static int band_osmo2femto(enum gsm_band osmo_band)
+{
+	switch (osmo_band) {
+	case GSM_BAND_850:
+		return GsmL1_FreqBand_850;
+	case GSM_BAND_900:
+		return GsmL1_FreqBand_900;
+	case GSM_BAND_1800:
+		return GsmL1_FreqBand_1800;
+	case GSM_BAND_1900:
+		return GsmL1_FreqBand_1900;
+	default:
+		return -1;
+	}
+}
+
+/**
+ * Select the band that matches the ARFCN. In general the ARFCNs
+ * for GSM1800 and GSM1900 overlap and one needs to specify the
+ * rightband. When moving between GSM900/GSM1800 and GSM850/1900
+ * modifying the BTS configuration is a bit annoying. The auto-band
+ * configuration allows to ease with this transition.
+ */
+int sysmobts_select_femto_band(struct gsm_bts *bts, uint16_t arfcn)
+{
+	enum gsm_band band;
+	struct gsm_bts_role_bts *btsb = bts_role_bts(bts);
+
+	if (!btsb->auto_band)
+		return band_osmo2femto(bts->band);
+
+	/*
+	 * We need to check what will happen now.
+	 */
+	band = gsm_arfcn2band(arfcn);
+
+	/* if we are already on the right band return */
+	if (band == bts->band)
+		return band_osmo2femto(bts->band);
+
+	/* Check if it is GSM1800/GSM1900 */
+	if (band == GSM_BAND_1800 && bts->band == GSM_BAND_1900)
+		return band_osmo2femto(bts->band);
+
+	/*
+	 * Now to the actual autobauding. We just want DCS/DCS and
+	 * PCS/PCS for PCS we check for 850/1800 though
+	 */
+	if ((band == GSM_BAND_900 && bts->band == GSM_BAND_1800)
+		|| (band == GSM_BAND_1800 && bts->band == GSM_BAND_900)
+		|| (band == GSM_BAND_850 && bts->band == GSM_BAND_1900))
+		return band_osmo2femto(band);
+	if (band == GSM_BAND_1800 && bts->band == GSM_BAND_850)
+		return band_osmo2femto(GSM_BAND_1900);
+
+	/* give up */
+	return -1;
+}