From ced29cf94cc0bfa82cf62a7b1fa48202145f3fb6 Mon Sep 17 00:00:00 2001 From: Vadim Yanitskiy Date: Mon, 21 Jun 2021 21:55:46 +0200 Subject: 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 --- tests/osmo-bsc.vty | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'tests') diff --git a/tests/osmo-bsc.vty b/tests/osmo-bsc.vty index 48f3f0b6f..22e2a0668 100644 --- a/tests/osmo-bsc.vty +++ b/tests/osmo-bsc.vty @@ -46,10 +46,14 @@ OsmoBSC# bts ? OsmoBSC# bts 0 ? resend-system-information Re-generate + re-send BCCH SYSTEM INFORMATION resend-power-control-defaults Re-generate + re-send default MS/BS Power control parameters + c0-power-reduction BCCH carrier power reduction operation trx TRX for manual command oml Manipulate the OML managed objects om2000 Manipulate the OM2000 managed objects +OsmoBSC# bts 0 c0-power-reduction ? + <0-6> Power reduction value (in dB, even numbers only) + OsmoBSC# bts 0 trx ? <0-255> TRX Number -- cgit v1.2.3