20 Jun
2009
20 Jun
'09
11:05 p.m.
Hi Dieter,
On Sat, Jun 20, 2009 at 11:23:31AM +0200, Dieter Spaar wrote:
mh. I see. Seems like there is some more research required here. With
the recent "L1 Info" IE decoding that I committed, we should always see
the actual RF power in dBm used by the MS during reception of measurement
results.
No, this is actually the inverse test: MAke sure the power does _not_ change
if TCH and BCCH are on the same TRX and we send different BS POWER values
for the TCH CHANNEL ACTIVATE. Right now we send a value of 15 (!).
I've once manually hacked it into it and was using it for a test. But there's
no real integrated/automatic support yet, no. Sorry. I think the latter will
be much easier once we have changed to a full vty-based configuration, since
we suddenly need to deal with different ARFCN's and command line arguments
are just not really a good idea to put all this information into.
CCCH is the channel that contains the BCCH. So I'm actually asking for
what you "don't think", i.e. an attempt to alter the BS POWRE on the TRX
that carries the BCCH.
As far as I read the specs, there should be no technical reason why it should
not respond to this request. Whether or not it implements it this way, we don't
know.
--
- Harald Welte <laforge(a)gnumonks.org> http://laforge.gnumonks.org/
============================================================================
"Privacy in residential applications is a desirable marketing option."
(ETSI EN 300 175-7 Ch. A6)
On Sat, 20 Jun 2009 10:02:17 +0200, "Harald
Welte" <laforge(a)gnumonks.org> wrote:
which I think is logical and might actually be demanded by the spec.
Do you get an error message (SET ATTRIBUTE NACK) if you try to set it?
I have not looked at the response, but LMT says "unrecognized value"
or something like that if I query the TRX attributes. The BS-11 seems
to use "6" if something larger than 6 is sent. The nanoBTS 1800 however does not start if an invalid
value for
NM_ATT_RF_MAXPOWR_R is sent, the green LED is just blinking.
ok. I suppose it sends an ATTRIBUTE NACK and thus doens't perform the
state transitions required to activate the TRX.
Yes, and looking at the test report of the BS-11 seems
to indicate that
there are 15 steps possible for dynamic adjustment (probably used only
if BTS power control is enabled).
ok.
MS power
control (the dynamic adjustment of MS power) should be used even
now, otherwise I would not understand my observation of the phone bursts
becoming much lesss loud in the speakers after the initial few very loud
bursts.
I can only report the results of a short test. According to LMT, the
MS power control is currently disabled when bsc_hack is used (at least
the version I use). If I enable it and additionally enable the whole
power control of the BS-11, I can see that the MS power is changed.
I guess the same is true for the BS power. 1) whatever we
use as BS POWER value in ACTIVATE CHANNEL on a TCH/SDCCH8
on the C0 does not make any changes to the acutal TX power
Difficult to measure for me with the current setup (ARFCN of the
traffic channel is the same as the BCCH channel). To find out if the
BS power of the traffic channel is modified, I have to switch to a
different ARFCN for traffic. 2) if we
activate a channel on the second TRX, do we see the BTS power
adjusted according to BS POWER in ACTIVATE CHANNEL ?
Does bsc_hack already support the second TRX ? 3) if we use a
BS POWER CONTROL message on the CCCH on C0 of an otherwise idle
BTS, do we see a power change on the TRX ?
I can only measure it if I switch the ARFCN to a different channel than
used by the BCCH. I don't think the BTS will modify the BCCH power.