While there is some commonality between the types of long-range communication technologies, they also are targeting different use cases and segments. The IoT architect should choose wisely which long-range system they intend to adopt. Like other components of the IoT system, the LPWAN is difficult to change once deployed. Considerations in picking the correct LPWAN include:
- What data rate does the IoT deployment need to use?
- Can the solution scale with the same LPWAN across regions? Is there proper coverage or does it need to be built?
- What range of transmission is appropriate?
- Is there any latency requirement for this IoT solution? Can the solution work with very high (multiple seconds) latencies?
- Are the IoT endpoints battery powered and what is the cost of servicing them?
- What are the cost constraints of the endpoints?
For reference, the following table details the similarities and differences between the LPWAN protocols highlighted in this chapter:
|
Specification |
Cat 0 (LTE-M) Release 12 |
Cat 1 Release 8 |
Cat M1 Release 13 |
Cat-NB Release 13 |
LoRa/LoRaWAN |
Sigfox |
|
ISM Bands |
No |
No |
No |
No |
Yes |
Yes |
|
Total Bandwidth |
20 MHz |
20 MHz |
1.4 MHz |
180 kHz |
125 kHz |
100 kHz |
|
Downlink Peak Rate |
1 Mbps |
10 Mbps |
1 Mbps or 375 Kbps |
200 Kbps |
0.3 to 5 Kbps adaptive |
100 bps |
|
Uplink Peak Rate |
1 Mbps |
5 Mbps |
1 Mbps or 375 Kbps |
200 Kbps |
5 Kbps to 5 Kbps adaptive |
600 bps |
|
Range |
LTE Range |
LTE Range |
~4x Cat-1 |
~7x Cat-1 |
5 kM urban, 15 kM rural |
up to 50 kM |
|
Maximum Coupling Loss (MCL) |
142.7 dB |
142.7 dB |
155.7 dB |
164 dB |
165 dB |
168 dB |
|
Sleep Power |
Low -- |
High ~2mA idle |
Very Low ~15 uA Idle |
Very Low ~15 uA Idle |
Extremely Low 1.5 uA |
Extremely Low 1.5uA |
|
Duplex Configuration |
Half/Full |
Full |
Half/Full |
Half |
Half |
Half |
|
Antennas (MIMO) |
1 |
2 MIMO |
1 |
1 |
1 |
1 |
|
Latency |
50-100 ms |
50-100 ms |
10-15 ms |
1.6-10 s |
500 ms to 2 s |
up to 60 seconds |
|
Transmit Power (UE) |
23 dB |
23 dB |
20 dB |
23 dB |
14 dB |
14 dB |
|
Design Complexity |
50% Cat-1 |
Complex |
25% Cat-1 |
10% Cat-1 |
Low |
Low |
|
Cost (relative pricing) |
~$15 |
~$30 |
~$10 |
~$5 |
~$15 |
~$3 |
|
Mobility |
Mobile |
Mobile |
Mobile |
Limited |
Mobile |
Limited |
Having covered the capture of data from a sensor to the communication of that data through PAN and WAN architecture, it is now time to discuss the marshaling and processing of IoT data. The next chapter is the first treatment of that data to package it, secure it, and route it to the correct location. That location may be an edge/fog node or the cloud. We will discuss the role of the gateway in providing that networking bridge and the ability to process data at the edge. We also will detail the type of IP-based communication protocols like MQTT and CoAP needed to stream data from the edge to the cloud. Later chapters will cover the ingestion, storage, and analysis of the data generated by the IoT.