Support in using slotmask

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Harald Welte laforge at gnumonks.org
Thu Oct 26 07:08:10 UTC 2017


Hi Mayuri,

On Thu, Oct 26, 2017 at 09:26:11AM +0530, Mayuri Tendulkar wrote:
> We want to test TX chain power on timeslot basis.

I see.

> Currently as all timeslots are enabled, I see power coming in all timeslots.

This is the correct behavior as per 3GPP specs for C0 (TRX 0) of a BTS,
which must always operate at constant full power.  Transmiting only
selective timeslots is only permitted for TRX1..N but not for TRX0.  I
understand you are not in normal operation but in a test setup, but the
code was written for normal operation :)

So my first question would be: Is it possible for you to do those tests
on TRX1..N of your BTS, or does it have to be on TRX0?  If it has to be
TRX0, we would most likely need to develop some (small) changes to
accomodate that.

On TRX1..N you can use the BSC command
	"bts <0-255> trx <0-255> timeslot <0-7> pdch (activate|deactivate)"
to activate a given timeslot or deactivate it.  It can be used at the
"enable" node of the BSC/NITB.

Unless you have valid uplink bursts in your test setup, you should also use
	"radio-link-timeout infinite"
which is a configuration command at the "bts" node in BSC/NITB.

> But if I want to make only alternate timeslot active, I tried changing
> slotmask as 10101010 in bts conf file. I also tried to change in code in
> trx_if.c.

This setting is a logical setting, it only affects which slots the L2/L3
will ever allocate/activate/use.  The purpose is (I believe) to work on
systems which have too limited processing power to handle all 8 slots.

Regards,
	Harald

-- 
- Harald Welte <laforge at gnumonks.org>           http://laforge.gnumonks.org/
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