Device to Cloud General Info Low Power Features
Cellular-based IoT can have a very low power footprint, especially if the low power modes are exploited correctly. As explained in section “here link to mobile network information”, these low power modes can greatly reduce the power consumption.
PSM
PSM (power saving mode) is the device’s deepest power state, minimizing power consumption.
PSM requires the configuration of two timers: the activity timer (T3324) and the periodic TAU timer (T3412). Their names are similar, so always refer to the full timer identifier (TXXXX) to avoid confusion.
The first timer configures how long the modem will stay active and connected to the network, while the second one defines the total duration of a PSM cycle. The sleep time will then be T3412 - T3324.
🚧 PSM availability in countries
The iotcreators (Deutsche Telekom) network natively supports PSM; however, when using iotcreators SIM cards in roaming, PSM needs to be supported by the local network as well in order to be enabled.
Please check the “Support over networks” section for details.
eDRX
eDRX (Extended Discontinuous Reception) is the low power mode that allows to save power while mantaining the modem as reachable from the network as intended. This mode is indicated if the end device needs to be reachable for downlinks from the network.
This is done by extending the time between the modem availability window. For LTE, this value is fixed at 2,56 seconds but, for NB-IOT and LTE-M, this value can be brought up to about 40 minutes, thus relaxing the power consumption spent being active.
In eDRX mode, the modem usually allows to configure the eDRX cycle duration only; the PTW (Paging time window) is provided and fixed by the network.
eDRX can be used in conjuction with PSM, in fact the activity timer defines the time that the eDRX will be working.
🚧 eDRX availability in countries
The iotcreators (Deutsche Telekom) network natively supports eDRX; however, when using iotcreators SIM cards in roaming, the eDRX needs to be supported by the local network as well in order to be enabled.
Please check the “Support over networks” section for details.
NON-IP data delivery (NIDD)
This is not actually a low power mode, but uses minimal overhead, making it well-suited for low power mode. This data delivery mode is only available with a dedicated network, and iotcreators provides such dedicated network.
🚧 NIDD APN
You cannot use noip under public network, because it requires a dedicated infrastructure to work. Please only use the dedicated noip APN provided by iotcreators: nonip.iot.t-mobile.nl
To send data over Non-IP, set the APN for Non-IP, which is “nonip.iot.t-mobile.nl” and the modem in Non-IP mode with:
AT+CGDCONT=0,"NONIP","nonip.iot.t-mobile.nl"
this command could be slightly different for your modem.
Then, to send data, just issue:
AT+CSODCP=0,4,"45726963"
or
AT+CSODCP=0,5,"Hello"
Where 4 or 5 in the example is the length in bytes and data can be in ascii or hex format.
👍 NIDD support
Noip data delivery is a standardized 3gpp feature. It is supported by all modems stated below, with the same command!
Non-IP currently has limited support on local networks.
Support over networks
You can find supported functionalities in the different countries here (this Excel file only covers coverage for SIM cards provided by iotcreators starting with 894xxx):
👍 NB-IOT and LTE-M coverage and low power modes availability
🚧 NB-IOT and LTE-M coverage and low power modes availability
These low-power features are, in general, better supported on NB-IoT than on LTE-M.
👍 Network information
PSM timers calculator
You can calculate the PSM timer values with this useful tool:
👍 PSM timers calculator