NB-IoT coverage and consumption

[Isaia Spinelli]

Hello,

I am a computer science student doing IoT network analysis with an nRF9160 DK and an IoT SIM card connected to the Swisscom network in Switzerland. While performing tests at my home where network coverage is not great, I noticed that the device easily connected to the network with LTE-Cat M (LTE-M) technology. Unfortunately, with NB-IoT (LTE Cat NB) technology, the device can't connect from my home, but does in a city not too far away.  

Is it normal that the sensitivity  of NB-IoT seems to be lower than that of LTE-M while in the literature we often read that the NB-IoT technology has a better penetration?

Moreover, I could notice that for the same application (using PSM mode), NB-IoT consumes more than 2 times more than LTE-M. Yet, in the literature we read that NB-IoT consumes less than LTE-M. This observation can also be seen with your online power profiler for LTE (https://devzone.nordicsemi.com/power/w/opp/3/online-power-profiler-for-lte). 

These two observations go against the literature. Do you have any ideas that could explain these observations please ?

P.S.: For NB-IoT and LTE-M, band 20 is used.

 

Thank you in advance for your answers,

Have a good day !

Isaia

[Charlie]

Hi Isaia,

Is it normal that the sensitivity  of NB-IoT seems to be lower than that of LTE-M while in the literature we often read that the NB-IoT technology has a better penetration?

if you are talking about one base station, this is not normal. Our experiment show NB-IoT has better penetration capability than LTE-M as the literature. I guess the cell station in your area may be only supported LTE-M not NB-IoT for some reason, you need to check with your local operator.

Moreover, I could notice that for the same application (using PSM mode), NB-IoT consumes more than 2 times more than LTE-M. Yet, in the literature we read that NB-IoT consumes less than LTE-M. This observation can also be seen with your online power profiler for LTE (https://devzone.nordicsemi.com/power/w/opp/3/online-power-profiler-for-lte). 

I agree that NB-IoT will consume less power in a similar condition, but in real practice, the energy efficiency performance will vary depending on many other effects. For example, the cell station setting of operators. If you choose for example Telenor Norway in the power profiler, the result is quite similar. 

Best regards,

Charlie

[Isaia Spinelli]

Hi Charlie,

Thanks you for your answers ! I am wainting for a response from my local operator.

Indeed, the power consumption depends very much on the configuration of the cell station of operators especially for LTE-M technology. For example it seems that Docomo Japan in the power profiler is the most power consuming. However, if the data transfer setting is enabled (upload), even with Docomo Japan's settings, the consumption is lower with LTE-M than with NB-IoT. And this remains true regardless of the data size setting and the data transfer interval setting.

So I don't understand why it says that NB-IoT consumes less energy than LTE-M. Do you have any experiments that could help me to understand please?

Best regards,

Isaia

[Charlie]

Hi Isaia,

Isaia Spinelli said:

So I don't understand why it says that NB-IoT consumes less energy than LTE-M. Do you have any experiments that could help me to understand please?

The power profiler is based on real experiments data. I also find some articles covering this topic. In conclusion, it is more meaningful to compare them in a fixed condiction. Even they target similar applications, there are still too many differences on the technical level, these parameters will affect power consumption a lot.

NB-IoT vs LTE-M: A comparison of the two IoT technology standards (onomondo.com)

LTE-M vs NB-IoT: 5 Considerations for Your IoT Solutions (emnify.com)

Best regards,

Charlie