As per 3GPP TS 45.008 sec 4.2, the ms_pwr received in L1 SACCH Header is
the value used over previous measurement period. Hence, we need to feed
the algo with the measurements taken over that same period.
Related: SYS#4917
Change-Id: I00852cb37a3613606e37476c169f5a32d6b5d75e
Field is renamed to look similar to similar fields in power control
loop. This is a preparation commit, next one will add functionality to
skip SACCH blocksi (P_CON_INTERVAL).
Related: SYS#5371
Change-Id: I169ce58ab827e38b64f4b15f935097a9118fa118
From TS 45.010 5.6.1 (delay tracking for circuit switched channels):
"""
Restricting the change in timing advance to 1 symbol period at a time
gives the simplest implementation of the BTS. However the BTS may use
a larger change than this but great care must then be used in the BTS design.
"""
In general 1 TA at a time (every 480ms of SACCH block) should be enough,
since section 5.6.3 states:
"""
The control loop for the timing advance shall be implemented in such a way that it will cope with MSs moving at a
speed up to 500 km/h
"""
Which is ~140 m/s, and 1 TA step around 500m, so most of the time we
should be save and no steps of more than 1 TA should be required.
However, unlikely changes from reflected to direct signal or vice versa
could produce higher increments, so let's increase the maximum step size
allowed to 2 in order to give more room.
Change-Id: I9e48faabf3090588233e274b2b39065cf85fbec7
First step improving and reworking TA loop:
Move trigger of the loop to similar place done by BS/MS Power Control
Loop, that is, upon receivial of UL SACCH block, which contains
information about the TA used to transmit the block encode in L1SACCH
Header. Hence, from computed received TOA and TA used when transmitting
from the MS, we can infer the desired TA to be used by the MS, which
will send back to it later during DL SACCH block.
The values taken are actually the ones calculated for the previous SACCH
block and stored in lchan->meas.ms_toa256. That's because L1SACCH
contains the TA used for the previous reporting period, similarly to
what's specified for MS Power Control loop (TS 45.008 sec 4.2):
"""
The MS shall confirm the power control level that it is currently employing
in the SACCH L1 header on each uplink channel. The indicated value shall
be the power control level actually used by the mobile for the last burst
of the previous SACCH period.
"""
(The reader may observe that currently this is not properly done for MS
Power Control loop when calling lchan_ms_pwr_ctrl(): this is a bug.)
This new method also permits changing TA quicker, since we have more
confidence that the TA we request is aligned with the one used to
transmit, and we don't simply increment/decrement based on the value we
request to transmit.
Related: SYS#5371
Change-Id: I2d0f128c8dcac93ee382283a1c91fca76623b8fc
Tests have shown that even a delay of 0, i.e. a simple defer until the
next select() loop, makes the difference from failing to working early
IA. So set the default to 0, achieving such defer.
Related: SYS#5559
Change-Id: I95365649edd51114bcf6028f0dc3bbe4186f96d2
During live testing, it has become apparent that some IMM ASS still fail
when sending the RR IMM ASS directly upon the target channel becoming
active.
Add a bit of delay after activation, to give some time for the channel
to light up for the MS. Default is 50ms.
Related: OS#5559
Change-Id: Ia1e63b98944dc840cde212fc732e20277cdc5585
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
If RxQual is considered good enough, attenuation can be increased in
order to lower overall cross-channel noise among different MS.
Change-Id: Ie97898980acd152de15f6b4b619d492048855ef4
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
All generated RTP that originates from the BTS relates to uplink. When
generating AMR BAD frame RTP packets, we must use ul_cmr/ul_ft and not
dl_cmr/dl_ft.
Change-Id: Ifa009819791cf7df2dd8201f442b0dae06f622a4
Related: SYS#5549
The AMR transmission phase directly depends on the frame number. The
transmission phase is used to tell if a received AMR frame contains a
CMI (frame type that is currently used) or CMR (frame type that the
receiver should use) codec identifier. The formulas in the present
implementation seem to be correct but they do not reflect the numbers in
the spec very well, nor do they have unit-tests. Lets replace them with
more readble functions and test those functions with unit-tests.
Change-Id: I94a934a6b3b397b4cd0e9da3577325de58814335
Related: SYS#5549
CMR and FT are updated each time an AMR voice frame is received from the
radio interface. The transmission phase decides whether the voice frame
contains CMR or FT. The code follows the transmission phase and keeps
ul_cmr and ul_ft up to date.
In contrast to the AMR frames on the radio interface, an AMR RTP packet
always contains the CMR and the FT value.
When generating the RTP payloed, The present implementation uses the CMR
in the position where the FT should be and the FT is ignored. This is not
correct.
Change-Id: I6bb10ff3c76f67b9830787497653b546cf27fe8e
Related: SYS#5549
struct ipac_preproc_cfg seems to suggest that there may be up to 3 IEs
in some cases:
"struct ipac_preproc_ave_cfg ms_ave_cfg[3];"
Change-Id: I02633713eb557ee52e790a239f7b13b8c5b2b3bd
Fixes: 9238c3549d
Related: SYS#4918
When generating GSMTAP, we are already suppressing generation for
fill frames on PCH and AGCH. Let's expand that also to dedicated
channels SDCCH, TCH/F and TCH/H. The fill frames just clog up the
logs without providing much benefit.
SACCH is still being logged, as it contains SI or MEAS REP, so every
active channel still sees GSMTAP traffic every 480ms (SACCH interval).
Change-Id: I0dd37d8848eb0379f84d15f5f006142b16823c6a
If for whatever reason the transmit queue of a TCH/{F,H} contains
neither speech frames nor signalling blocks, osmo-bts-trx would
currently transmit garbage. Of course, this causes decoding
errors at the MS side.
Ideally, we should employ an ECU (Error Concealment Unit) for the
given codec in use. However, a simpler solution is to transmit
dummy LAPDm frames over FACCH. This is what e.g. nanoBTS does.
Change-Id: I868afecbcb6890f40c8f146e3ce00e836b794dd3
Related: OS#4823
We have two osmocom specific timers used in the BTS, X1 and X2. Expose
those on the VTY configuration, as timer group 'bts'.
This prepares for a subsequent patch, where I would like to add another
configurable timer. This provides the basic infrastructure for that.
Related: SYS#5559
Change-Id: I0f56f9425134679219884b0c3c2f29e77aff5e64
This is not as trivial as with OsmoBSC or OsmoMSC, because normally the
osmo-bts process exits right away when there is no BSC. Hence add
--vty-test option to main.
Use 'osmo-bts-virtual --vty-test' for testing. The other BTS models
require dependencies / configure switches to be built.
Essentially copied from osmo-bsc.git:
configure.ac: add --enable-external-tests
tests/Makefile.am: add 'vty-test' target
Add osmo-bts.vty, some trivial VTY node testing.
This prepares for adding VTY tests for T timer configuration added in a
subsequent patch.
Related: SYS#5559
Change-Id: I730daf548a3a9bb116aa8b6d5772ca9af0ada08f
When an Immediate Assignment comes in targeting an lchan that is not yet
active, then hold back the RR Immediate Assignment until the channel
becomes active.
This allows the BSC to send the Immediate Assignment before first
waiting for the Channel Activation ACK, saving one Abis roundtrip, and
helping avoid double allocation on high latency Abis links.
Related: SYS#5559
Related: I56c25cde152040fb66bdba44399bd37671ae3df2 (osmo-bsc)
Related: Ifb2c62431a91dafa6116b5d6b9410930f00a6e18 (osmo-ttcn3-hacks)
Change-Id: Ie52765b238b01f22fb327fe12327fbf10abcad4c
At the moment we can only configure a single BSC in the BTS
configuration. This also means that if this single BSC fails for some
reason the BTS has no alternate BSC to connect to. Lets extend the
remote-ip parameter so that it can be used multiple times so that an
operater can configure any number of BSCs that are tried one after
another during BTS startup.
Change-Id: I205f68a3a7f35fee4c38a7cfba2b014237df2727
Related: SYS#4971
Make gcc 11.1.0 false positivies happy
After my system's gcc was upgraded, I get false positivies in a couple
places. Let's initialize those to make gcc happy.
"""
//git/osmo-bts/src/common/vty.c: In function ‘lchan_summary’:
//git/osmo-bts/src/common/vty.c:1881:23: error: ‘ts’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
1881 | lchan = &ts->lchan[lchan_nr];
| ~~~~~~^~~~~~~~~~~~~~~~~~~~~~
//git/osmo-bts/src/common/vty.c:1869:20: error: ‘trx’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
1869 | ts = &trx->ts[ts_nr];
| ~~~^~~~~~~~~~~~~~~~~
//git/osmo-bts/src/common/vty.c:1852:34: error: ‘bts’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
1852 | if (trx_nr >= bts->num_trx) {
"""
Change-Id: I93477142a5a4b3f3829b7398d6e564c127263596
When the paging queue is filled up to a critical level, pagings from the
PCU should be dropped as each immediate assignment paging from the PCU
is worth 4 normal CS pagings. Also the PCU may still issue pagings if the
paginging queue is already full and CS pagings are dropped. In a
congestion situation it is more important to get the CS rather than PS
pagings through.
Change-Id: I30f97672d7a0c369c4a656e878ab8cbbd83e31ea
Related: SYS#5306
Instead of using tlvp_val16_unal() and then doing ntohs() here
and there, convert the remote port to the host byte order once.
Change-Id: Id883a976a03fd3022ed9d66f703b01244df2d9db
They will gain support to be activated as SDCCH/8 soon too.
Related: SYS#5309
Depends: libosmocore.git I56dcfe4d17899630b17f80145c3ced72f1e91e68
Change-Id: Ia617d20fc52f09dbab8f4516c06fa1efac08e898
BS Power Control is not allowed on the BCCH/CCCH carrier, unless
the BTS is operating in the BCCH carrier power reduction mode.
Allow constrained BS power reduction (up to 6 dB) on active logical
channels iff BCCH carrier power reduction mode is enabled.
Change-Id: I3299b6cdd230d3767321c3d6c64d468b7f5e1d02
Related: SYS#4919, SYS#4918
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.
The power reduction operation can be controlled by the BSC by
sending BS POWER CONTROL on the A-bis/RSL with the Channel Number
IE set to 0x80 (RSL_CHAN_BCCH). This makes osmo-bts reduce the
transmission power on inactive timeslots of the BCCH carrier.
This is a non-standard, Osmocom specific extension, so indicate
support of this feature to the BSC in the feature vector. Also
add a VTY command to allow enabling/disabling the power reduction
locally. Add some signalling notes to the A-bis/RSL manual.
For more details, see 3GPP TS 45.008, section 7.1.
Change-Id: I3dcee6e910ccc61c5c63c728db9ea04327e2fc98
Depends: I69283b3f35988fc7a1a1dcf1a1ad3b67f08ec716
Related: SYS#4919
This is required for ttcn3-bsc-test, see change [1].
Change-Id: I765d5e38cb0746e0458773abf3717ee9bf1cb7d1
Related: [1] I084f7736cd7d09b68ed49f8ba52a14de928d4c01
Related: SYS#4919
This reverts commit cd30a40be1.
As a part of SYS#4919 "BTS energy saving", we want to support
constrained (up to 6 dB) BS power control on BCCH carriers.
Change-Id: I0d2b48c4b2af2d8e94f4ad02fa4774dbd0a0a654
Related: SYS#4919
This new extension protocol is used to forward Osmocom PCUIF messages
BSC<->BTS<->PCU.
It will be sent re-using the IPA multiplex of the OML link between
BSC and BTS. BTS is responsible for forwarding the message over the unix
socket to the PCU.
PCUIF existing RX path needs to be reworked in order to accept
variable-size messages, in order to be able to transparently forward
messages without knowing about them (the new container message is
variable-length).
Related: SYS#5303
Change-Id: I73fdb17107494ade9263a62d1f729e67303fce87
I introduced this regression in [1] during a massive refactoring.
Basically, I copy-pasted a chunk from trx_sched_ph_data_req(), but
forgot to change the union field. This broke voice calls, because
all TCH.req primitives would be enqueued to wrong timeslot.
Change-Id: If841e6ac40a3c6344c304ab970755d6a2d292156
Fixes: [1] I7c4379e43a25e9d858d582a99bf6c4b65c9af481
The PDCH multiframe contains 48 data slots, 2 PTCCH slots, and
2 IDLE slots. The later two can be used for the interference
measurements, since the UEs shall not transmit on them.
bts_report_interf_meas() is called every 104 TDMA frames, what
corresponds to 2 PDCH multiframe periods. Report interference
levels on PDCH timeslots from this function.
Change-Id: I56f83db5264c246ec1b4b8a973105a4fc09931fb
Related: SYS#5313, OS#1569
Pau Espin
Neels Hofmeyr
Philipp Maier
Oliver Smith
Harald Welte
Vadim Yanitskiy
Eric Wild