Usual allocation mechansim, when some signalling channel is needed,
first tries to reserve an SDCCH, and if all of them are exhausted, then
attempts to reserve a TCH as a last resort.
This, however, may cause TCH starvation under certain situations, for
instance if there high load on other services (LU, SMS, etc.).
Hence, it may be desirable for the operator to forbid reservation
of TCH slots once SDCCH become exhausted. This commit is thus adding a
VTY command which allows forbidding it. The default behavior (allow using
TCH timeslots when SDCCHs are exhausted) is kept as before.
The above mentioned prohibition is applied only to non-voicecall related
signalling services. That's because voicecall services will end up
requiring a TCH anyway, and forbidding reservation of TCH straighaway
when SDCCHs are exhausted would mean no voice calls could be initiated
while still TCHs would be available.
Related: SYS#5548
Change-Id: Ib08027125145df26602069bfb51847063b0ccc0c
Store the config option whether the channel allocator should try to
avoid lchans with higher interference levels reported in RES IND.
The actual implementation of avoiding interference follows in
I844494092193811dfd9fa4d52983cbaed0fc9248
Related: SYS#5313
Change-Id: I8b62d0b41ad9e908b27713db9219e3dbc1ebaab7
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
Add VTY command to trigger an intra-cell re-assignment, also allowing to
re-assign to a secondary VAMOS lchan.
Related: SYS#5315 OS#4940
Change-Id: If006f5caaf83b07675f57e5665cfa79328da55e6
A subsequent patch will add to this VTY command, so let's first test the
current status as a baseline.
Change-Id: I6379e306fb8fa6ec227125c6cf14893d674e7596
At this point, meas-feed is usable again, however, osmo-bsc is not able to
include the IMSI in every report like osmo-nitb did.
In consequence, the meas-vis and meas-web tools are unable to handle the
current measurement reports: these so far use the IMSI to list reports, and all
reports without an IMSI are collapsed onto the same line, swapping values.
So though osmo-bsc now sends usable measurement reports via meas-feed, two
avenues to improve should be pursued:
OS#3192: the visualization tools should use bts,ts,ss numbers, not IMSI.
OS#2969: osmo-bsc should always know a mobile identity.
Related: OS#2968
Change-Id: I186c7a995dd2b81746c32a58b55da64ed195a1ce
Pau Espin
Neels Hofmeyr
Vadim Yanitskiy