According to 3GPP TS 08.58, section 9.3.4, BS Power IE indicates
the transmission power attenuation on a particular channel:
+--------------+---------+-----------------+
| Reserved (3) | FPC (1) | Power level (4) |
+--------------+---------+-----------------+
so let's change handling of this IE as follows:
- s/bs_power/bs_power_red/g, so it reflects 'reduction';
- store power attenuation value in dB, not in 2 db steps;
- get rid of ms_power_ctrl.bts_tx_pwr, it's always 0 anyway;
- fix rsl_tx_meas_res(): use lchan->bs_power_red;
- always check if FPC (Fast Power Control) flag is set;
- we don't support it, so reject messages containing it;
- fix rsl_rx_chan_activ(): properly apply the bitmask.
Change-Id: I16cc50dfca102030380a06e16c234d5f6698f38f
The nominal transmit power is still only configurable manually from
osmo-bts-trx VTY interface. Support to retrieve the nominal power
from osmo-trx will come later.
Change-Id: Ia7c353e4c199e0fc3bcab55c45a4abda2c66d2c1
In case a system has a high-gain external PA (like a 40dB PA) connected
externally, we cannot simply switch the transceiver to 0 dBm in
trx_init() only to then start the ramping at much lower levels once the
PHJ completes in trx_init_compl_cb(). The result would be a short
0 + 40 dBm spike followed by later ramping. We want to avoid that
spike, particularly its associated inrush current, so let's bring up the
board with smething very conservative like -50 dBm, and then ramp from
there.
Change-Id: I0ad91fce64f65e0213c9fcfde3390ace519055db
Fixes: SYS#3259
It seems more user friendly to look at a calibration table in terms of
the delta (positive or negative) compared to the nominal gain value,
rather than a collection of absolute gain values. It has the added
benefit that the (API/data model) user doesn't have to specify a gain
value for each ARFCN, but rather can rely on the default nominal gain in
absence of a calibration table for this specific unit.
Change-Id: I7311815902a88d2fc9d211cf4c62fa6fdc5e86ad
We use the completion call-back from L1 to compare the instructed
TRX board output power with the actual value as reported back from
L1.
Right now we only print an error message in case the values disagree.
In the future we might want to either use that value as part of our
calculation or send an OML alarm report to the BSC.
In order to support transmit power reduction by thermal management
as well as the variety of new internal / external PA configurations
of BTSs, we need a slightly more complex system.
Also, as at high power a single dB can be quite a big difference,
we are now doing all computations in milli-dB(m), i.e. 1/10000 bel.
Ramping is now used both for up and down ramping, as that is useful in
cases where you want to gracefully shut down a cell by shrinking its
radius, gradually handing over subscribers to neighboring cells.
Furthermore, this code is becoming part of the 'common' codebase, as it
is not really specific to how sysmobts is working.
The user can specify a single aggregate value for external system
gain/attenuation. Let's say you have 1dB loss of antenna cable, so you
can put that as 'user-gain -1' into the config, which means that a
'transmit power of 20dBm' will be compensatet for that and the TRX is
instructed to output 21dBm to compensate the cable loss. Similarly,
external PAs can be described by a positive user-gain.
One of the next steps will be to communicate those values and the
nominal power capability of the specific BTS to the BSC, so the BSC will
automatically show correct signal levels in the VTY and log files.
The code includes provisions for future extensions regarding
* an external and an internal PA with calibration tables
* a thermal attenuation setting to be controlled by the site manager
Vadim Yanitskiy
Pau Espin
Harald Welte