Improved generation of SYSTEM INFORMATIONs 2* and 5* for neighbour bands

In addition to SI 2 and SI 5, the SI 2ter and 2bis is generated, if
neighbour cells in other bands exist. Also it is indicated in the rest
octets of SI3, that SI 2ter is used. If no neighbour cell in a different
band exists, the SI 2ter and SI 5ter is omitted.

A special case is P-GSM range (channels 1-124). To be compatible with
older phones, SI 2bis and SI 5bis is used. If the BCCH lays inside the
P-GSM band, only neighbour cells of the P-GSM range are included in
SI 2 and SI 5. If neighbour cells exist in the same band (900), but lay
outside the P-GSM range, the SI 2bis and SI 5bis is used to extend the
list of neighbour cells. The extension is also indicated in SI 2 and
SI 5. If the BCCH lays inside the P-GSM range, but no neighbour cell
exists in the same band outside the P-GSM range, the SI 2bis ans SI 5bis
are omitted.

1 files changed, 43 insertions, 20 deletions

diff --git a/openbsc/src/libbsc/bsc_init.c b/openbsc/src/libbsc/bsc_init.c
index 441c0a9f0..6d00374e0 100644
--- a/openbsc/src/libbsc/bsc_init.c
+++ b/openbsc/src/libbsc/bsc_init.c
@@ -95,18 +95,10 @@ int bsc_shutdown_net(struct gsm_network *net)
 	return 0;
 }
 
-static int generate_and_rsl_si(struct gsm_bts_trx *trx, enum osmo_sysinfo_type i)
+static int rsl_si(struct gsm_bts_trx *trx, enum osmo_sysinfo_type i, int si_len)
 {
 	struct gsm_bts *bts = trx->bts;
-	int si_len, rc, j;
-
-	/* Only generate SI if this SI is not in "static" (user-defined) mode */
-	if (!(bts->si_mode_static & (1 << i))) {
-		rc = gsm_generate_si(bts, i);
-		if (rc < 0)
-			return rc;
-		si_len = rc;
-	}
+	int rc, j;
 
 	DEBUGP(DRR, "SI%s: %s\n", get_value_string(osmo_sitype_strs, i),
 		osmo_hexdump(GSM_BTS_SI(bts, i), GSM_MACBLOCK_LEN));
@@ -134,11 +126,11 @@ static int generate_and_rsl_si(struct gsm_bts_trx *trx, enum osmo_sysinfo_type i
 			}
 		} else
 			rc = rsl_sacch_filling(trx, osmo_sitype2rsl(i),
-					       GSM_BTS_SI(bts, i), rc);
+					       GSM_BTS_SI(bts, i), si_len);
 		break;
 	default:
 		rc = rsl_bcch_info(trx, osmo_sitype2rsl(i),
-				   GSM_BTS_SI(bts, i), rc);
+				   GSM_BTS_SI(bts, i), si_len);
 		break;
 	}
 
@@ -150,6 +142,8 @@ static int set_system_infos(struct gsm_bts_trx *trx)
 {
 	int i, rc;
 	struct gsm_bts *bts = trx->bts;
+	uint8_t gen_si[_MAX_SYSINFO_TYPE], n_si = 0, n;
+	int si_len[_MAX_SYSINFO_TYPE];
 
 	bts->si_common.cell_sel_par.ms_txpwr_max_ccch =
 			ms_pwr_ctl_lvl(bts->band, bts->ms_max_power);
@@ -159,26 +153,55 @@ static int set_system_infos(struct gsm_bts_trx *trx)
 
 	if (trx == bts->c0) {
 		/* 1...4 are always present on a C0 TRX */
-		for (i = SYSINFO_TYPE_1; i <= SYSINFO_TYPE_4; i++)
-			bts->si_valid |= (1 << i);
+		gen_si[n_si++] = SYSINFO_TYPE_1;
+		gen_si[n_si++] = SYSINFO_TYPE_2;
+		gen_si[n_si++] = SYSINFO_TYPE_2bis;
+		gen_si[n_si++] = SYSINFO_TYPE_2ter;
+		gen_si[n_si++] = SYSINFO_TYPE_3;
+		gen_si[n_si++] = SYSINFO_TYPE_4;
 
 		/* 13 is always present on a C0 TRX of a GPRS BTS */
 		if (bts->gprs.mode != BTS_GPRS_NONE)
-			bts->si_valid |= (1 << SYSINFO_TYPE_13);
+			gen_si[n_si++] = SYSINFO_TYPE_13;
 	}
 
 	/* 5 and 6 are always present on every TRX */
-	bts->si_valid |= (1 << SYSINFO_TYPE_5);
-	bts->si_valid |= (1 << SYSINFO_TYPE_6);
+	gen_si[n_si++] = SYSINFO_TYPE_5;
+	gen_si[n_si++] = SYSINFO_TYPE_5bis;
+	gen_si[n_si++] = SYSINFO_TYPE_5ter;
+	gen_si[n_si++] = SYSINFO_TYPE_6;
+
+	/* Second, we generate the selected SI via RSL */
+
+	for (n = 0; n < n_si; n++) {
+		i = gen_si[n];
+		bts->si_valid |= (1 << i);
+		/* Only generate SI if this SI is not in "static" (user-defined) mode */
+		if (!(bts->si_mode_static & (1 << i))) {
+			rc = gsm_generate_si(bts, i);
+			if (rc < 0)
+				goto err_out;
+			si_len[i] = rc;
+		} else {
+			if (i == SYSINFO_TYPE_5 || i == SYSINFO_TYPE_5bis
+			 || i == SYSINFO_TYPE_5ter)
+				si_len[i] = 18;
+			else if (i == SYSINFO_TYPE_6)
+				si_len[i] = 11;
+			else
+				si_len[i] = 23;
+		}
+	}
+
+	/* Third, we send the selected SI via RSL */
 
-	/* Second, we generate and send the selected SI via RSL */
 	for (i = SYSINFO_TYPE_1; i < _MAX_SYSINFO_TYPE; i++) {
 		if (!(bts->si_valid & (1 << i)))
 			continue;
 
-		rc = generate_and_rsl_si(trx, i);
+		rc = rsl_si(trx, i, si_len[i]);
 		if (rc < 0)
-			goto err_out;
+			return rc;
 	}
 
 	return 0;