path: root/src/osmo-bsc/bsc_vty.c
diff options
authorVadim Yanitskiy <vyanitskiy@sysmocom.de>2021-06-21 21:55:46 +0200
committerfixeria <vyanitskiy@sysmocom.de>2021-07-05 12:17:59 +0000
commitced29cf94cc0bfa82cf62a7b1fa48202145f3fb6 (patch)
tree5bab9715c73cd5d95098ad3d3182d986fa57be9b /src/osmo-bsc/bsc_vty.c
parenta4de0fea51547b431fcbc7e143a3b05e4db69d03 (diff)
power_control: implement BCCH carrier power reduction operation
The BCCH carrier (sometimes called C0) of a BTS shall maintain discontinuous Downlink transmission at full power in order to stay 'visible' to the mobile stations. Because of that, early versions of 3GPP TS 45.008 prohibited BS power reduction on C0. However, starting from version 13.0.0 (2015-11) there is a feature called 'BCCH carrier power reduction operation'. This is a special mode of operation, where the variation of RF level for some timeslots is relaxed for the purpose of energy saving. In BCCH carrier power reduction operation, for timeslots on the C0 carrier, except timeslots carrying BCCH/CCCH, the output power may be lower than the output power used for timeslots carrying BCCH/CCCH. In this case the maximum allowed difference in output power actually transmitted by the BTS is 6 dB. Introduce a VTY command to turn on and off the BCCH carrier power reduction operation. Also introduce a CTRL command. On the A-bis/RSL, abuse the BS POWER CONTROL message by setting the Channel Number IE to 0x80 (RSL_CHAN_BCCH). Currently, only osmo-bts-trx is supported. A value greater than zero makes it reduce the power on *inactive* timeslots of the BCCH carrier. Sending zero disables the BCCH power reduction mode completely. For more details, see 3GPP TS 45.008, section 7.1, and 3GPP TR 45.926. Change-Id: I047fce33d4d3e4c569dd006ba17858467a2f4783 Related: SYS#4919
Diffstat (limited to 'src/osmo-bsc/bsc_vty.c')
1 files changed, 42 insertions, 0 deletions
diff --git a/src/osmo-bsc/bsc_vty.c b/src/osmo-bsc/bsc_vty.c
index 7207341a1..efa59d3e1 100644
--- a/src/osmo-bsc/bsc_vty.c
+++ b/src/osmo-bsc/bsc_vty.c
@@ -444,6 +444,8 @@ static void bts_dump_vty(struct vty *vty, struct gsm_bts *bts)
if (strnlen(bts->pcu_version, MAX_VERSION_LENGTH))
vty_out(vty, " PCU version %s connected%s", bts->pcu_version,
+ vty_out(vty, " BCCH carrier power reduction (maximum): %u dB%s",
+ bts->c0_max_power_red_db, VTY_NEWLINE);
vty_out(vty, " MS Max power: %u dBm%s", bts->ms_max_power, VTY_NEWLINE);
vty_out(vty, " Minimum Rx Level for Access: %i dBm%s",
@@ -6020,6 +6022,45 @@ DEFUN(bts_resend_power_ctrl_params,
+ bts_c0_power_red_cmd,
+ "bts <0-255> c0-power-reduction <0-6>",
+ "BTS Specific Commands\n" BTS_NR_STR
+ "BCCH carrier power reduction operation\n"
+ "Power reduction value (in dB, even numbers only)\n")
+ int bts_nr = atoi(argv[0]);
+ int red = atoi(argv[1]);
+ struct gsm_bts *bts;
+ int rc;
+ bts = gsm_bts_num(gsmnet_from_vty(vty), bts_nr);
+ if (!bts) {
+ vty_out(vty, "%% No such BTS (%d)%s", bts_nr, VTY_NEWLINE);
+ return CMD_WARNING;
+ }
+ if (red % 2 != 0) {
+ vty_out(vty, "%% Incorrect BCCH power reduction value, "
+ "an even number is expected%s", VTY_NEWLINE);
+ return CMD_WARNING;
+ }
+ rc = gsm_bts_set_c0_power_red(bts, red);
+ if (rc == -ENOTSUP) {
+ vty_out(vty, "%% BCCH carrier power reduction operation mode "
+ "is not supported for BTS%u%s", bts_nr, VTY_NEWLINE);
+ return CMD_WARNING;
+ } else if (rc != 0) {
+ vty_out(vty, "%% Failed to %sable BCCH carrier power reduction "
+ "operation mode for BTS%u%s", red ? "en" : "dis",
+ bts_nr, VTY_NEWLINE);
+ return CMD_WARNING;
+ }
+ return CMD_SUCCESS;
/* this command is now hidden, as it's a low-level debug hack, and people should
* instead use osmo-cbc these days */
DEFUN_HIDDEN(smscb_cmd, smscb_cmd_cmd,
@@ -8172,6 +8213,7 @@ int bsc_vty_init(struct gsm_network *network)
install_element(ENABLE_NODE, &restart_bts_cmd);
install_element(ENABLE_NODE, &bts_resend_sysinfo_cmd);
install_element(ENABLE_NODE, &bts_resend_power_ctrl_params_cmd);
+ install_element(ENABLE_NODE, &bts_c0_power_red_cmd);
install_element(ENABLE_NODE, &pdch_act_cmd);
install_element(ENABLE_NODE, &lchan_act_cmd);
install_element(ENABLE_NODE, &lchan_act_all_cmd);