LTE-M effective throughput

[JOEBRE]

Using the Online Power Profiler for LTE we saw that nRF9160 would require 0.115 s to upload 4-kbit of data into the mobile network.

This is an U throughput of  ~34-kbit/s which is ~ 10 time smaller than the nominal maximal rate! Is this correct ? what is the typical Up throughput I've to expect ?

Thanks, Joel

[Håkon Alseth]

Hi,

 

Sending a single payload vs. sending as-much-as-you-can is two different scenarios, and please also remember that this is a calculator, and should be used as a indicator and not a 100% accurate model.

Using the Online Power Profiler for LTE we saw that nRF9160 would require 0.115 s to upload 4-kbit of data into the mobile network.

As an example, it takes approx. 900 ms to send 10 times as much, which indicates that there is a bit of overhead.

 

If you want to see how fast your link is in your area, I would suggest that you try the download sample:

https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/samples/net/download/README.html

Or you can use iperf, as done in this thread:

 nRF9160 DK maximum throughput 

  

Kind regards,

Håkon

[JOEBRE]

Ok I understand this just a simulator ... I was just surprised by this huge overestimation of the effective data transfer phase duration (if it would have been half the maximum rate I would not have been alarmed ... ) we are planning to develop an geo-monitoring remote sensing station to be deployed around Europe... depending on configuration (specific to each deployment site) the required upload throughput is in the range [10...40 kbit/s]. Data is uploaded into a server once per hour using nRF9160 ... I wanted to understand if nRF9160 LTE-M is an option to be taken into consideration or the risk of ending up with an insufficient transfer bandwidth would be too high.

What is a safe margin factor to be applied to the maximum bandwidth in order to be sure not ending up with an insufficient transfer bandwidth ? :10 ? :100 ? This is our first project using potentially this technology... we therefore do not have a feeling about what is safe and what is not...

thanks , Joel

[Håkon Alseth]

Hi Joel,

 

For data transfer scenarios, I would always recommend that you test in your targeted network, as timing and such may change from network-to-network. That being said, a effective transfer of 10-40 kBit/s should not be a problem with LTE-M at all, even if you use a TCP based transport (which uses a 3-way ACK).

 

It all depends on the RSRP (signal strength) of the link, but in "normal use-cases", around 100 kBit/s should be obtainable with a TCP based protocol (and even better with a UDP based one).

 

Feel free to reach out if you have any questions or run into any issues.

 

Kind regards,

Håkon 

[JOEBRE]

many thanks for the answer ...

Joel