Wireless IoT Network Protocols - Connectivity

Wireless IoT Network Protocols: 

LTE-M:

It is part of the 1.4MHz block. LTE-M is more energy efficient because of its extended discontinuous repetition cycle (eDRX), which means the endpoint can communicate with the tower or the network on how often it will wake up to listen for the downlink. This can be anywhere from 10s to 40 minutes or more.

While LTE-M1 allows you to go up to really high data rates, you can also benefit from new architectures like LTE eDRX and PSM, which can help you benefit from the same power budget that NB-IoT or SigFox benefit from.

NB-IoT:

Works on a 200kHz band (Standalone - unused GSM band or otherwise; LTE Gaurd Band, LTE In Band). It has 20dB better coverage than LTE (164dB Max Coupling Loss), Low cost (<$5), Long Battery Life (> 10 years); bi-directional data rates of 300bps to 200kbps for small bursts of packet delivery.

SigFox:

Works in ISM bands (Industrial, Scientific and Medical (ISM) radio bands) - which in the US is the 915 MHz band (Europe has a narrower band around 868 MHz) - unlicensed spectrum on 0.1kHz signal bandwidth. It has Low cost modules (<$5), however it is uplink only (slow 100bps); Though limited downlink is possible, it has a different link budget, and is very restricted; and signal interference can become an issue. Sigfox is an end-to-end network and technology player.

SigFox has faced challenges in moving their technology into the US market. Under FCC Part 15, the law that governs the use of the unlicensed radio spectrum, the maximum time a transmission can be on the air is 0.4 seconds. Since SigFox transmissions are 3 seconds or so, this has required a new architecture, and is the likely reason they have been slower to deploy in the US than promised. The frequency band in the US is also subject to much higher levels of interference than the band SigFox uses in Europe.

LoRaWAN:

Works on unlicensed spectrum. LoRa is a proprietary modulation system (called, frac-N phase lock loop (PLL) - BPSK or QPSK is the modulation of NB-IOT) sold by Semtech corporation. They are defacto the only chipset manufacturer or license holder for LoRa. LoRa itself does not describe system functionality above the physical (RF medium) layer. LoRaWAN, is the protocol for WAN communications when LoRa is used as a wide area network technology. It has date rate of 10kbps and works on 125kHz signal bandwidth.

References:

1. https://www.link-labs.com/blog/complete-list-iot-network-protocols
2. https://www.iotforall.com/iot-connectivity-comparison-lora-sigfox-rpma-lpwan-technologies/
3. https://www.ietf.org/proceedings/96/slides/slides-96-lpwan-7.pdf
4. http://www.samsung.com/global/business-images/insights/2016/IoT-Whitepaper-0.pdf
5. https://novotech.com/docs/default-source/default-document-library/lte-m-optimizing-lte-for-the-internet-of-things.pdf?sfvrsn=0
6. https://arxiv.org/ftp/arxiv/papers/1606/1606.04171.pdf
7. https://www.u-blox.com/en/blog/iot-and-four-reasons-why-licensed-spectrum-technologies-have-been-worth-wait
8. https://www.lora-alliance.org/technology