When using 'check_PROGRAMS', autoconf/automake generates smarter
Makefiles, so that the test programs are not being compiled during
the normal 'make all', but only during 'make check'.
Change-Id: I18ebb7395024a490da743c0bcb20959e6e9c7017
As a side effect, we have to sacrifice a unit test (TC_inval_dummy)
because it becomes impossible to pass a dummy or invalid SACCH block
to lchan_bs_pwr_ctrl().
Change-Id: I937117cf26fb718d57920382f6972390ad498c51
Related: SYS#4918
This test showcases the current issue where the loop keeps bouncing
between 2 good MS Power Level values due to the loop "accepting" and
"reporting back" the previously considered good MS Power Level
announced/used by the MS. Hence, upon report back from the network, the
MS will switch to this new MS Power Level, and same thing will ocurr
over and over.
Related: SYS#4917
Change-Id: I16ed7fe8a123b99008e0c041d2f3e4232057d55c
TS 45.008 section 4.7.1:
"""
Upon receipt of a command from an SACCH to change its power level on the corresponding uplink channel, the MS
shall change to the new level at a rate of one nominal 2 dB power control step every 60 ms (13 TDMA frames), i.e. a
range change of 15 steps should take about 900 ms. The change shall commence at the first TDMA frame belonging to
the next reporting period (as specified in subclause 8.4). The MS shall change the power one nominal 2 dB step at a
time, at a rate of one step every 60 ms following the initial change, irrespective of whether actual transmission takes
place or not.
"""
Since the reported MS_PWR in L1 SACCH Header is, according to specs, the
one used for the last block of the previous SACCH period, it becomes
clear the first SACCH block after a requested MS Power Level change by
the network may contain mismatches between the announced MS_PWR by the
MS and the measured Rxlev/RxQual. Hence, let's better use a
P_CON_INTERVAL of 1 which retriggers the MS Power Control Loop every second
SACCH block.
Change-Id: If6cb8945645a2031f2b2ee65d9b9f51e75cd9af1
Related: SYS#5371
The bug showed up in previous commit and is fixed in this commit. It can
be seen how rounding error is carried over time in the average
measurement, and affects final values.
Change-Id: I680d1c94bd4bae179b14b26662a819fa1462a5c8
Before this comits, averaging and delta calculation was done in RSSI,
but stored the averaging cached state in variables named "rxlev", which
was really confusing. Let's keeping averaging and delta calculations
based on RxLevels.
Some of the tests change results due to test passing RSSI -45, which is
an invalid Rxlev (only up to -47 is supported).
Others fail due to an unrelated bug showing up now. Basically the averaging algo
is doing rounding the wrong way when downscaling the values. It will be
fixed in a follow-up commit.
Change-Id: I4cff8394f22b5d47789163051364ff594b2bcd74
params->rxqual_meas.upper_thresh is left unchecked in
lchan_bs_pwr_ctrl() on this commit on purpose, to keep this
commit with old behavior wrt to algo logic.
Change-Id: If7e3987df89d680cfa443195ab2f225681d0e6cf
This commit reworks the code in function lchan_bs_pwr_ctrl()
and logging to look similar to that of lchan_ms_pwr_ctrl(), so that
reader can easily spot similarities between both and add simillar
features more easily.
This commit is also a preparation to add EWMA avg support for RxQual
measurements. Logging is also reworked now to look similar to that of MS
Power Control Loop, because having several parameters driving the algo
(RxLev and RxQual), it becomes more suitable to log all of them together instead
of intermediate info only aplicable to one param such as "delta".
Change-Id: Ida76b55f0da722135eb61ed06ea2b3a1862df600
This commit extends existing MS Power Control Loop algorithm to take
into account computed C/I values on the UL, received from MS. The
related C/I parameters used by the algorithm are configured at and
provided by the BSC, which transmits them to the BTS similar to already
existing parameters.
Using C/I instead of existing RxQual is preferred due to extended
granularity of C/I (bigger range than RxQual's 0-7).
Furthermore, existing literature (such as "GSM/EDGE: Evolution and Performance"
Table 10.3) provides detailed information about expected target values,
even different values for different channel types. Hence, it was decided
to support setting different MS Power Parameters for different channel
types.
These MS Power Parameters are Osmocom specific, ie. supported only by
newish versions of osmo-bts. Older versions of osmo-bts should ignore
the new IEs added just fine. The new IEs containing the MS POwer
Parameters are not send for non osmo-bts BTSs, hence this commit is
secure with regards to running osmo-bsc against an ip.access BTS such
as nanoBTS.
Related: SYS#4917
Depends: libosmocore.git Change-Id Iffef0611430ad6c90606149c398d80158633bbca
Change-Id: I5dfd8ff9ab6b499646498b507624758dcc160fb6
Let's disable category here since we don't care about its formatting here.
In any case, every test relying on logging output validation should
always explicitly state the config to avoid issues in the future if
default values change.
Change-Id: I8713f4e04e92b4d7e211c499fc6e78983edfb139
Related: OS#5034
One part of the algorithm simply provides a _suggested_ 'delta' that
needs to be applied to the current power level, while the other part
ensures that this suggested value does not exceed the limits. Thus
it's possible that some logging messages would state that the power
reduction value remains unchanged, while the 'detla' != 0.
Change-Id: I7496a158b9ac6074a965056d708d8078a98cb1aa
Related: SYS#4918
This change makes BS power control loop:
- take the lower RxQual threshold (L_RXQUAL_XX_P) into account, so
the BS power is increased only if RxQual exceeds this threshold;
- apply the configured increase step size instead of reducing the
current attenuation by half.
MS power loop is not affected, it does not even handle RxQual yet.
Change-Id: Ib3c740b9a0f3ba5dfb027e144dc13f456cb26ae2
Related: SYS#4918
It makes more sense to use a reduce step size that is smaller than
the increase step size. This way both MS/BS power control loops
would be able to react quickly of the signal gets weaker, while
the good signal would not trigger radical power reduction.
Change-Id: Ie358fd828a68bfa1d23559197e8df8478fb4535e
Related: SYS#4918
In change [1] the new power control structures and default params
were introduced. In change [2], the existing VTY commands for MS
power control in the BTS were deprecated and changed to use the
new structures as storage. Finally, in change [3], handling of
the power control parameters on the A-bis/RSL was implemented.
This change is the final logical step in the mentioned chain: it
makes both MS/BS power control loops use the new parameters, and
removes the old structures. The actual implementation of both
power control loops remains the same, however the expected output
of some unit tests for the Downlink loop needs to be changed:
- TC_fixed_mode: disabling dynamic power control becomes a separate
step of the test script since the field 'fixed' is removed;
- TC_rxlev_target: RxLev thresholds are printed 'as-is'.
Not all of the new parameters are used by the power control loops
yet. Further improvements to be done in the follow up commits.
[1] I6d41eb238aa6d4f5b77596c5477c2ecbe86de2a8
[2] Icbd9a7d31ce6723294130a31a179a002fccb4612
[3] I5a901eca5a78a0335a6954064e602e65cda85390
Change-Id: Ib18f84c40227841d95a36063a6789bf63054fc2e
Related: SYS#4918
We already have MS Power Control, which according to 3GPP 45.008
shall be implemented in the MS to minimize the transmit power in
the Uplink direction. The BS Power Control may optionally be
implemented by the network side for the same purpose.
Using Downlink signal measurements reported by the MS, the BSS
(either BSC, or BTS) may control Downlink attenuation in a way
that the transmit power remains as low as possible, or remains
in a specific range corresponding to good RxLev values on the
MS side. This change implements autonomous BS Power Control,
that can optionally be enabled by the BSC.
BS Power Control re-uses parts of the MS Power Control code,
so all parameters can be configured in the same way - via the
VTY interface or a configuration file. This basically means
that features like hysteresis and EWMA based filtering are
also available for BS Power Control.
The only difference is that RxQual values higher than 0 would
trigger the logic to reduce the current attenuation twice.
Note that one of the unit tests ('TC_rxlev_max_min') fails,
as the power step limitations for raising and lowering look
wrong to me, and the related discussion is still ongoing.
Change-Id: I5b509e71d5f668b6b8b2abf8053c27f2a7c78451
Related: SYS#4918
Similar to I3c07cb6e14acd5a988761bbc51a9c3b60fb22d87, this change
is another step towards separating the common delta calculation
logic from lchan_ms_pwr_ctrl(), since this function will loose
access to the averaged values.
On the one hand, the affected logging statements are getting
less precise; on the other, logging the averaged value as the
actual value ('rx-current') may be even more confusing.
Change-Id: I07007e45c859b4080fbbe520ffb5ccc0bb9c4244
Related: SYS#4918
This change would allow to separate the common logic from
lchan_ms_pwr_ctrl() and re-use it for Downlink power control.
The logging statement was quite useful during early stages
of development and testing of hysteresis and filtering,
but now we can sacrifice it.
Change-Id: I3c07cb6e14acd5a988761bbc51a9c3b60fb22d87
Related: SYS#4918
This would allow to pass only two pointers:
- 'struct bts_power_ctrl_params', and
- 'struct lchan_power_ctrl_state',
and get rid of 'struct gsm_lchan' dependency. The later is
exactly where all state variables are supposed to be kept.
Change-Id: Idfefca30f4944bc722b4e9d8f1685eb77670a9db
Related: SYS#4918
Recently we've introduced EWMA based uplink power filtering, that
should reduce Uplink power oscillations. However, the power loop
is still quite sensitive to small deviations from the target power
level: even such an insignificant deviation like 2-5 dBm triggers
the loop to increase or decrease the MS power level. Even if the
EWMA based filtering is enabled with 80% smoothing (alpha = 0.2).
This change introduces a new configuration parameter - 'hysteresis':
uplink-power-target <-110-0> hysteresis <1-25>
that together with the 'uplink-power-target' defines a range:
[target - hysteresis .. target + hysteresis]
in which the MS power loop would not trigger any power changes.
This feature is now *enabled* by default, so given that:
- default 'uplink-power-target' is -75 dBm, and
- default 'hysteresis' is 3 dBm,
the default target Uplink power range is: -78 dBm ... -72 dBm.
Change-Id: Iacedbd4d69d3d74e2499af5622a07a8af0423da0
Related: SYS#4916
It makes no sense to do further calculations if the actual Uplink
signal strength equals the target value configured in the VTY.
Change-Id: Id99c7013a722403e773df8367b1a9d7a856e639b
Related: SYS#4916
So far the Uplink power control loop did not filter the Uplink RSSI
measurements (reported by the BTS) at all. The lack of filtering
makes our implementation too quick on the trigger, so in the real
deployments there will be unneeded Tx power oscillations.
In order to reduce this effect, let's implement a very simple EWMA
(also known as Single Pole IIR) filtering that is defined as follows:
Avg[n] = a * Pwr[n] + (1 - a) * Avg[n - 1]
where parameter 'a' determines how much weight of the latest UL RSSI
measurement result 'Pwr[n]' carries vs the weight of the average
'Avg[n - 1]'. The value of 'a' is usually a float in range 0 .. 1, so:
- value 0.5 gives equal weight to both 'Pwr[n]' and 'Avg[n - 1]';
- value 1.0 means no filtering at all (pass through);
- value 0.0 makes no sense.
This formula was further optimized with the use of '+=' operator.
The floating point math was also eliminated by scaling everything
up (by 100). For more details, see:
https://en.wikipedia.org/wiki/Moving_averagehttps://en.wikipedia.org/wiki/Low-pass_filter#Simple_infinite_impulse_response_filterhttps://tomroelandts.com/articles/low-pass-single-pole-iir-filter
The EWMA filtering is now *enabled by default*, but can be disabled
or (re-)configured over the VTY at any time:
! Completely disable filtering
no uplink-power-filtering
! Enable EWMA smoothing with the given parameters
uplink-power-filtering algo ewma beta <1-99>
Note that the VTY command expects 'beta' instead of 'alpha':
alpha = (100 - beta)
and the value must be in %. This is done for simplicity:
1% means lowest smoothing,
99% means highest smoothing.
Let's say we have EWMA filtering enabled with alpha = 0.4, and get
-98 dBm on the input, while the last output value was -60 dBm.
The new output would be:
Avg[n] = 0.4 * Pwr[n] + 0.6 * Avg[n - 1]
Avg[n] = (0.4 * -98) + (0.6 * -60)
Avg[n] = -75.2 => around -75
Of course, this is not a silver bullet, but better than nothing.
Change-Id: Ib6dcadbf14ef59696c6a546bd323bda92d399f17
Related: SYS#4916
It's not a good idea to request big changes in MS Power based on
sporadic bad signal received, let's instead change announced MS power
levels more smoothly to avoid possible big signal strength fluctations,
similar to what is already done in osmo-bts-trx specific loop (loops.c).
Related: OS#1851
Change-Id: Iecc4ec7e21471ec853ad2d5659af4052aba5444c
Several improvements have been made lately to MS Power Control loop from
osmo-bts-trx in loops.c. Let's port these to the common algorithm.
Related: OS#1851
Change-Id: I579967cc8bb69dc76a315c6c9d3a351f5961d92f
Thies field is used to store and retrieve whether MS power needs to be
calculated and updated by osmo-bts software or autonomously by lower
layers. Previous name was not clear
and may have been understood as indicating whether MS Power Control loop
is done or not in general, and the responsible for that is located under
lchan's ms_power_ctrl.fixed.
Related: OS#1851
Change-Id: Ic690ab69866a7377f1597e24aa7b0214831c1cbe
All code in osmo-bts goes through APIs in libosmotrau (osmo_ortp.h),
hence direct dependency is not needed. Fixes OBS warnings:
dpkg-shlibdeps: warning: package could avoid a useless dependency if debian/osmo-bts-trx/usr/bin/osmo-bts-trx was not linked against libortp.so.9 (it uses none of the library's symbols)
dpkg-shlibdeps: warning: package could avoid a useless dependency if debian/osmo-bts-virtual/usr/bin/osmo-bts-omldummy debian/osmo-bts-virtual/usr/bin/osmo-bts-virtual were not linked against libortp.so.9 (they use none of the library's symbols)
Change-Id: I96a9b5f0678331dcf66c007928866a124d8700de
gsm_bts_role_bts was introduced at a time when we still shared
gsm_data_shared.[ch] between BSC and BTS, and where we then subsequently
needed a BTS-private structure. Since that sharing was abandoned quite
some time ago, we can merge gsm_bts_role_bts into gsm_bts and do away
with the bts/btsb dualism in a lot of the code.
Change-Id: I4fdd601ea873d9697f89a748cc77bcf7c978fa3e
Power control loop test outputs next to nothing which is not very
helpful. Make it more verbose. While at it, also move duplicated code
into static function to make test cases less cluttered.
Change-Id: I0a5e65e23e62442ef8758ecbcf8e7820b4f15d7b
Related: OS#2223
There's nothing sysmobts specific in this test so let's move it into
separate directory and run unconditionally. The test itself is unaltered
except for intro text.
Change-Id: I0d1957cd9cf5497826be095c7a42b7bb4fa10397
Related: OS#2223
Vadim Yanitskiy
Pau Espin
Harald Welte
Philipp Maier
Max