@afzal_m

Ok then I will go the hard way 🙂

The electronic lab of our university owns a spectrum analyzer. Next week I will try to investigate which command produces traffic and which not 🙂

Im a little bit overcorrect in building clean solutions. Sorry for consuming your time 🙂

Btw: our goal is also to minimize signaling storms from inefficient IoT devices not supporting the TS.34 Radio Policy Manager (RPM) feature. What’s your experience with TS.34 RPM so far?

@Martijn-Kooijman I solved it by checking the return message after sending “AT+USOCR=17,7000”. Once it is contains “+USOCR: 0” in the returning string I know it is ok:
(it takes about 5 s after a reset)
added code:

String check_sara=cmd("AT+USOCR=17,7000"); while ((check_sara.indexOf("+USOCR: 0",1)<0)) { delay(500); check_sara=cmd("AT+USOCR=17,7000"); Serial.println(check_sara);//just for checking }

NB-IoT is designed for use cases where end devices need no maintenance for a long period of time. The battery lifetime depends on several factors: power consumption of the radio module, power consumption of the sensor, how often messages are transmitted and the coverage conditions of the end device, among others.

The 3GPP estimated that for a setup with average radio modules and sensors transmitting at a moderate frequency (e.g. 2-3 times a week) in good coverage conditions using two AA cells a battery lifetime of up to 10 years can be expected. However, deviations must be expected in different setups with higher frequency of transmissions i.e. Smart Parking.

“T3324” is the timer for the PSM Activity Timer (how long the Idle Mode lasts before PSM mode is started). It depends of the device request, i.e. if the device requests 10s than MME accepts since the activation of dynamic PSM.

“T3412” is the timer for the Long Periodic TAU (how long the UE can stay ATTACHed before the packet core releases the session. This value is currently set to 310 hours default. The UE may request a value, but currently this is overwritten by the network default. This behavior will change in the future.

Both as dynamic PSM AT and dynamic LP-TAU will allow to retain the values proposed by UE. Most of the operators within DT’s footprint support dynamic PSM and LP-TAU, but may differ in min./max. values.

Power saving mode (PSM) and Long Periodic TAU (LP-TAU) are covered by NB-IoT over classical LTE.

NB-IoT has three power saving features:

PSM (Power Saving Mode): Puts radio module into sleep mode to save power. When a power saving feature is active, it is not possible to initiate a downlink connection from the server to the device. It can only be woken up by a timer or own sensors. Upon wake-up, since the data session (PDP context) stays valid, no energy is needed to re-register (re-attach) the device at the network. Long Periodic TAU (LP-TAU): Extends the standard sleeping interval by setting a long TAU (Tracking Area Update) period. eDRX: Useful if frequent paging (“listening”) is required. By switching off the receive section of the radio module for few seconds or more, the UE is able to save power. Whilst not providing the same levels of power reduction as PSM, eDRX may provide a good compromise between device reachability and power consumption.