Hi,
We're noticing high power consumption when the 9160 is supposed to be PSM sleeping in borderline signal locations that is breaking our power consumption model, reducing 8+ months of potential battery use to just a couple of weeks.
Our device is on a 30 minute PSM sleep cycle, waking up for 20 seconds, sampling sensors, uploading to the cloud. We can detect connectivity loss during the wake cycle and can easily enough back off for several hours for a retry. However when the 9160 is sleeping the modem firmware is upping its PSM communication window power when the signal is borderline or temporarily lost, and doesn't seem to have any backoff logic itself. Seems the PSM communication window logic in US AT&T is to poll every 40sec,
Normal signal strength consumption profile (total PCB power consumption)
- 30 min SLEEP - 90uA
- 20 sec AWAKE - 50mA
Low signal strength consumption profile
- (SLEEP)
20s @ 40mA, 40s @ 90uA,
20s @ 40mA, 40s @ 90uA,
2 or 5s @ 40mA, 40s @ 90uA,
2 or 5s @ 40mA, 40s @ 90uA
repeat for whole PSM sleep cycle
Is there a notification mechanism for the modem firmware to signal to the app that it can't communicate with the cell infrastructure during the PSM sleep cycles?
Any advice on how to best manage power on the 9160 when signal strengths are low?
Thanks!
