Sigfox Coverage Measurement Methodology With the CheckFox
Introduction
With using the CheckFox, you are trying to find an answer to these questions:
Does the predicted coverage match the actual coverage?
Will a reference device work at the installation spot?
What is the attenuation between reference measurement and final destination?
What is the reliability of the reception over time?
Will my own CheckFox work as well as the reference device?
Always use a reference device - any development kits are mostly unusable.
Also please keep in mind that Sigfox is susceptible to fading in motion. Do all the measurements without any movement. If you want to measure while driving, take the fading and the position of base stations in relation to the vector and speed of movement into account while evaluating the results.
We developed the following methodology and checklist that you can print out and use as a guideline.
Measurement protocol
General data
Aim of the measurement:
A Coverage
B Final place coverage
C Attenuation
D Reliability in time
E Your own hardware performance
Before measurement
Ensure that you are using a reference device.
Check the antenna not being loose.
Check the device voltage.
Decide what you want to measure and how you will evaluate the results.
Reference measurement
Place the device 1.3 m above ground under open sky, at least 1m away from any obstacle.
Hold the CheckFox in a vertical position and don't move. Ideally, place the device on a tripod but a car or holding it in your hand should be fine.
Take a photo of the device.
Take a photo of the environment.
Ensure you have a GPS fix.
Select Outdoor at 1.3 meters (4.3feet) in the Main menu.
Select how many messages you want to send
Ideally you would repeat the measurement three times while shifting the device in a triangle by 8-9cm (lambda/4) every measurement.
Check that the predicted coverage roughly matches the predicted coverage in the Dashboard. In case the predicted coverage is much worse, please contact the local Sigfox operator immediately, provide them with photos of the environment and a GPS position.
Assess the results of the A aim.
Final installation place measurement
Perform a reference measurement.
Perform multiple measurements for each location.
Select your final location.
Take a photo of the device and the environment.
Select location in Menu and select Final destination measurement or Final with delay in case the final destination is behind closed doors or the device needs to be lowered on a string. The measurement starts in 30 seconds.
Assess the results of B Final place coverage target.
Compare the measurements to the reference measurement in the Dashboard and asses the C Attenuation (don't forget to subtract the SNR).
Time reliability
Make a time series measurement at the Final destination with either hourly or 10-minute interval.
Assess the D Reliability in time by analyzing message loss.
Performance check of your own hardware
Do the Final installation place measurement with the reference device.
Take a photo of your own hardware in the same Final destination.
Do the Final installation measurement with your own device.
Assess the E Your own hardware performance. Pay attention to message loss and how many repetitions of the messages you see. If you see only 1 repetition, then the battery design is most likely poor and the battery doesn't have enough power to emit the second and the third repetition. Or the device antenna is detuned and does not perform properly.
Results
Does the actual coverage match the predicted one? same/better/worse
Does the reference device work in the Final installation? yes/no/little bit
What is the attenuation of the Final installation in comparison with reference measurement? Number 0-70
How is the long term reliability of messages? excellent/good/bad
How does my own hardware perform in comparison with the CheckFox? better/same/worse/far worse
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