Specifications

Cinterion
®
ALAS5V Hardware Interface Description
4.3 Power Saving
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ALAS5V_HID_v00.030a 2019-03-20
Confidential / Preliminary
Page 82 of 124
4.3 Power Saving
ALAS5V is able to reduce its functionality to a minimum (during the so-called SLEEP mode) in
order to minimize its current consumption. The following sections explain the module’s network
dependent power saving behavior. The power saving behavior is further configurable by AT
command:
• AT^SCFG= "MEopMode/PwrSave": The power save mode is by default enabled. While
inactive, the module stays in power save (SLEEP) state, waking up only upon any of the
following events:
- Cyclically to meet basic technical demands, e.g. network requirements (such as regularly
listening to paging messages from the base station as described in Section 4.3.1, Section
4.3.2 and Section 4.3.3.
- Cyclically after expiry of a configured power saving period.
- Data at any interface port, e.g., URCs for incoming calls.
- A level state transition at GPIO3, GPIO5, GPIO7, GPIO8, or GPIO16 (if configured).
• AT^SCFG= "MEopMode/ExpectDTR": Power saving will take effect only if there is no trans-
mission data pending on any of the module’s USB ports. The expect DTR AT command
ensures that data becoming pending on any USB port before an external application has
signaled its readiness to receive the data is discarded. By default this behavior is enabled
for all available USB CDC ACM and CDC ECM ports.
• AT^SCFG="Radio/OutputPowerReduction": Output power reduction is possible for the
module in GPRS multislot scenarios to reduce its output power according to 3GPP 45.005
section.
Please refer to [1] for more information on the above AT commands used to configure the mod-
ule’s power saving behavior.
The implementation of the USB host interface also influences the module’s power saving
behavior and therefore its current consumption. For more information see Section 2.1.3.
Another feature influencing the current consumption is the configuration of the GNSS antenna
interface. For details see Section 3.1.
Also note that the module does not wake up from SLEEP mode just to measure the supply volt-
age, and that the command AT^SBV reports an average over the values it was able to measure
last (see also Section 4.4.3). Therefore, the shorter the power saving periods are, the faster
and more precisely will the reported average adjust to possible voltage changes.
4.3.1 Power Saving while Attached to GSM Networks
The power saving possibilities while attached to a GSM network depend on the paging timing
cycle of the base station. The duration of a paging timing cycle can be calculated using the fol-
lowing formula:
t = 4.615 ms (TDMA frame duration) * 51 (number of frames) * DRX value.
DRX (Discontinuous Reception) is a value from 2 to 9, resulting in paging timing cycles
between 0.47 and 2.12 seconds. The DRX value of the base station is assigned by the GSM
network operator.