Change in osmo-bsc[master]: power_control: implement BCCH carrier power reduction operation

fixeria gerrit-no-reply at
Mon Jun 21 18:26:55 UTC 2021

Hello Jenkins Builder, laforge, pespin, 

I'd like you to reexamine a change. Please visit

to look at the new patch set (#2).

Change subject: power_control: implement BCCH carrier power reduction operation

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, in the recent 3GPP TS 45.008 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 new 'bs-power-c0' configuration command, complementing
the existing 'bs-power' command, in order to allow constrained BS
power reduction on *active channels* of the BCCH carriers.

In lchan_fsm_wait_ts_ready_onenter(), distinguish between the
BCCH and non-BCCH carriers, apply the appropriate default value.

Change-Id: Id7c2cf80309532f57621342826acc0e9639733cd
Related: SYS#4919
M include/osmocom/bsc/gsm_data.h
M src/osmo-bsc/bsc_vty.c
M src/osmo-bsc/gsm_data.c
M src/osmo-bsc/lchan_fsm.c
M tests/power_ctrl.vty
5 files changed, 72 insertions(+), 11 deletions(-)

  git pull ssh:// refs/changes/39/24739/2
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Gerrit-Project: osmo-bsc
Gerrit-Branch: master
Gerrit-Change-Id: Id7c2cf80309532f57621342826acc0e9639733cd
Gerrit-Change-Number: 24739
Gerrit-PatchSet: 2
Gerrit-Owner: fixeria <vyanitskiy at>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: laforge <laforge at>
Gerrit-Reviewer: pespin <pespin at>
Gerrit-MessageType: newpatchset
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