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FORUM

Coverage - SNR issue

LoRa Basics™
#1

Hi all,

I work for Cibicom that has the ambition to deliver LoRa coverage to entire Denmark.

The other day, I did make some measurement tests and I did realize that the signal-to.noise ratio (SNR) drops significantly in suburban/village areas as well as in forest area. Is there any options to improve the SNR?
In the figure below you can see an example. The RSSI-value drops about 15 dBm and the SNR is -16 dB, so in total, the signal quality is about 30 dB worse in the village compared to the field, which is a lot - improving the SNR will make the signal quality much better.

image
image895×713 263 KB

Hopefully you have a solution for the issue. If you have any question, don’t hesitate to ask them.

Best regards,
Jes

#2

Looks like the Gateway antenna is not very high and as soon as houses get in the way the signal starts droping off.

Only one solution really, put the Gateway antennas as high as possible and make sure there are no nearby obstructions. The variations in SNR you see are the normal differneces in propagation. Having the node antennas higher would help also.

Are you selling LoRaWAN as a service to your customers in Denmark ?

#3

Hi Stuart,

Thanks for your reply.

The gateway antenna is mounted about 300 meters agl (above ground level), so it’s not an option to put the gateway antenna much higher in order to improve the SNR. :slight_smile:
There is no technology that can reduce the reflected signals/differences in propagation? Or do I have to keep in mind that the LoRaWAN-technology is very sensitive in areas like urban, village, forests etc.?

Yes, we are selling LoRaWAN as a service to our customers meaning that we ensure coverage to the customers devices. For instance, now we have a collaboration with SGDD, where we ensure LoRaWAN-coverage to theirs water meters such that the information like water flow are given to theirs customers.

In addition we own the tallest masts in Denmark (up to 300 meters), which are used to deliver DTT- and DAB-broadcast to whole Denmark. These masts are also used to deliver LoRaWAN-coverage.

Do you develop LoRaWAN-devices?

#4

Better and directional antennas maybe, but then that would very likley make the nodes\Gateways illegal to use.

Good very low noise amplifiers (very expensive) can help on the receiver side but that introduces significant complexities in seperating the RX and TX signal paths.

LoRa is already operating on the limits of what is possible distance wise, do not assume its so simple to make it ‘better’.