LPWAN technology for remote environmental monitoring

Question

What would be the most appropriate LPWAN technologies for environmental monitoring in a remote area, given the following:

• The monitoring system would be made up of 3 to 10 nodes located within a circular (star) pattern with a diameter of at least 5 km.
• Each node sends data on a minute's basis.
• The location is a rural/forested area on hilly terrain in Slovenia (southern central Europe)
• The nodes should be energy efficient, however there is a possibility of connecting a central node (gateway) to mains power and the internet using Ethernet.
  
  

I am mostly looking into the following technologies:

• GPRS (coverage in the area is not ideal, high energy consumption, sunsetting technology)
• NB-IoT (not yet adopted by network carriers, unknown date)
• Sigfox (no coverage, possibility of deploying a Micro Base Station)
• Ingenu (most promising technology, no info on coverage or local base station possibilities)
• LoRaWAN (no coverage, possibility of deploying a gateway)

Answer 1

Be aware that with LoRaWAN (and others ISM technologies), you have to follow the local regulation about duty cycle as you will use ISM radio band.

If you are at a distance of around 5km, you may need to use a large spreading factor meaning you will spread the data on air, and so use more airtime.

In Europe, you have (basically) 1% of air time allow. See this acticle

So to be able to send every minutes, you payload must be very short or you must use a smaller spreading factor, to comply with regulation. To get a idea you can is this spreadsheet

Answer 2

I did a case study on LoRaWAN in 2015. Since then the community is continuously growing. The case study was about installing one Gateway in our city.

I find it one of the best solution because

• Low power consumption (As a node reports to Gateway, 3 AAA batteries lasts for more than a month)
• Low cost devices (The Things Uno)
• Long range wireless network (Up to 10 km or 6 miles)
• Huge community support (Communities)
• Future plans to support multiple Bluetooth Broadcast/Mesh networks. (Topology options)