Notes on LPWA network and development boards

Low-power wide-area network

LTE-M = includes eMTC (enhanced Machine Type Communication) NB-Iot = narrow band https://blog.onomondo.com/nb-iot-vs-lte-m-a-comparison-of-the-two-iot-technology-standards

Make sure to check what is implemented. Example

LTE-M only: SMS, voice

Voice is not implemented @DT

EU bands: 8-20-3

M2M SIM options

Default lifetime estimated for regular SIM cards is 2-5 years.

eSIM - 6x5mm or 2x1mm package

eUICC – a secure element that features one or more subscription profiles. eUICC is compatible with eSIM and removable SIMs. In effect, each profile enables the eUICC to function like a removable SIM.

eUICC platforms still have lock-ins.

nuSIM - SIM functions goes into the modem

Coverage Enhancement Level

Providing deep indoor coverage NB-IOT 0-1-2, number of retransmissions, increase coupling loss LTE-M A,B increase coupling loss

Power Saving Mode

Whilst it has always been possible for a device’s application to turn its radio module off to conserve battery power, the device would subsequently have to reattach to the network when the radio module was turned back on. The reattach procedure consumes a small amount of energy, but the cumulative energy consumption of reattaches can become significant over the lifetime of a device. Therefore, battery life could be extended if this procedure could be avoided.

extended Long-Periodic Tracking Area Updates (Long-Periodic TAU) eg. in DT network between 1 hour and 310 hours - final value is determined by the network maximum in standard is 413 days

The network retains the state information and the device remain registered

Timers: * PSM Acitivity T3324 - during which the device remains idle, listening paging msgs * Long Periodic TAU T3412 - effectively sleep time

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Extended Discontinous Reception

Paging procedure - device listens to the network on regular intervals to check for incoming data

Timers: * Paging Transmission Window (T PTW): Time during which the device performs the DRX procedure, which can accommodate between 4 and 16 paging reception slots. * eDRX Cycle (T eDRX): Time between the start of two consecutive PTW windows.

Between those two times, the IoT device module or chipset enters a so-called “Sleep Mode” during which the receive path of the radio chipset is deactivated.

eg. eDRX between 20,48s and 10485,76s (~175min) PTW between 2,56s and 40,96s

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Early Release Assistance Inicator

By activating the Early Release Indication, the IoT device is able to go straight into the Idle Mode after data transmission and/or reception, thus bypassing the RRC_CONNECTED state (which is typically 20-30 seconds long). Depending on the chipset solution being used, this means that up to 50mA of current may be saved by the IoT device.

Send data to inform the network that no subsequent uplink or downlink data transmission is expected.

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