laforge submitted this change.
fix gsm_bts_get_cbch(): CBCH can be allocated on Cn
According to 3GPP TS 45.002, table 3, unlike the CCCH+SDCCH/4+CBCH
combination, which can only be allocated on C0/TS0, the SDCCH/8+CBCH
can be allocated on C0..n/TS0..3. In other words, having CBCH on
e.g. C1/TS2 is perfectly legal. This is why in gsm_bts_get_cbch()
we should check all transceivers, not just the C0.
Without this change osmo-bts does not send CBCH Load Indications
at all if the CBCH is allocated on C1..n.
Change-Id: Ib5976783b53521047fbdfc18e0e236e8bce8eaae
Related: osmo-bsc.git Ie79ccff4f8f0f1134757ec0c35e18b58081cc158
Related: SYS#5905
---
M src/common/bts.c
1 file changed, 11 insertions(+), 10 deletions(-)
diff --git a/src/common/bts.c b/src/common/bts.c
index 4e49c45..0608df1 100644
--- a/src/common/bts.c
+++ b/src/common/bts.c
@@ -883,22 +883,23 @@
/* return the gsm_lchan for the CBCH (if it exists at all) */
struct gsm_lchan *gsm_bts_get_cbch(struct gsm_bts *bts)
{
- struct gsm_lchan *lchan = NULL;
struct gsm_bts_trx *trx = bts->c0;
+ /* According to 3GPP TS 45.002, table 3, CBCH can be allocated
+ * either on C0/TS0 (CCCH+SDCCH4) or on C0..n/TS0..3 (SDCCH/8). */
if (trx->ts[0].pchan == GSM_PCHAN_CCCH_SDCCH4_CBCH)
- lchan = &trx->ts[0].lchan[2];
- else {
- int i;
- for (i = 0; i < 8; i++) {
- if (trx->ts[i].pchan == GSM_PCHAN_SDCCH8_SACCH8C_CBCH) {
- lchan = &trx->ts[i].lchan[2];
- break;
- }
+ return &trx->ts[0].lchan[2]; /* C0/TS0 */
+
+ llist_for_each_entry(trx, &bts->trx_list, list) { /* C0..n */
+ unsigned int tn;
+ for (tn = 0; tn <= 3; tn++) { /* TS0..3 */
+ struct gsm_bts_trx_ts *ts = &trx->ts[tn];
+ if (ts->pchan == GSM_PCHAN_SDCCH8_SACCH8C_CBCH)
+ return &ts->lchan[2];
}
}
- return lchan;
+ return NULL;
}
/* BCCH carrier power reduction (see 3GPP TS 45.008, section 7.1) */
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