Bug #1024 related power measurement of the GSM modem

Joerg Reisenweber joerg at openmoko.org
Tue Dec 2 13:00:12 CET 2008


Am Di  2. Dezember 2008 schrieb Dieter Spaar:
> Hello Stefan,
> 
> Stefan Schmidt wrote:
> > To follow up on the #1024 traces. I fear you are still not able to 
reproduce the
> > re-camping?
> >   
> 
> No, I cannot reproduce it here. It seems that it requires a special GSM
> net situation.
> 
>  From the PCO2 logs you made, it look like this without applying the
> AT%SLEEP=2 workaround (Thank you for allowing to post this trace
> overview). All times are relative, CID is the cell ID:
> 
> 00:06:04:667   MMR_REG_CNF received: LAC: 0020, CID: DACC
> 00:09:37:249   MMR_REG_CNF received: LAC: 0020, CID: DAB8
> 00:11:45:560   MMR_REG_CNF received: LAC: 0020, CID: 00CA
> 00:12:41:293   MMR_REG_CNF received: LAC: 0020, CID: C834
> 00:14:24:681   MMR_REG_CNF received: LAC: 0020, CID: DACC
> 00:14:48:234   MMR_REG_CNF received: LAC: 0020, CID: DAB8
> 00:15:23:502   MMR_REG_CNF received: LAC: 0020, CID: 00C0
> 00:16:22:414   MMR_REG_CNF received: LAC: 0020, CID: DACC
> 00:16:49:465   MMR_REG_CNF received: LAC: 0020, CID: 00CA
> 
> It seems that you have at least five cells for your network around
> which can be received with a similar level. [ Hey, I think I have
> buy more BS-11 base stations and  install all of them to get
> something similar here ;-) ]
> 
> On a first look the cell re-selections are done because
> the GSM modem has decided that a different cell is better
> than the current one. I would say that this is not necessarily
> a wrong behavior of the GSM modem.

Please check C1/C2 threshold levels. Usually this *is* an erratic behaviour of 
GSM.

> 
> The situation is similar with the AT%SLEEP=2 workaround applied:
> 
> 00:03:44:457   MMR_REG_CNF received: LAC: 0020, CID: DAB8
> 00:03:58:336   MMR_REG_CNF received: LAC: 0020, CID: 00CA
> 00:04:32:477   MMR_REG_CNF received: LAC: 0020, CID: DACC
> 
> (The trace is shorter so there are not that many cell re-selections).

So we see the same unpleasant behaviour here as well :-(
Seems sleep=2 won't stop it.
Is this really an active complete cell reselect? Could you check if there's 
GSM TX activity each time we see "MMR_REG_CNF received:" please.


cheers
jOERG
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