LTE-M or NB-IoT, that is the question…

Roman Dyzhyk

Hey IoT Creators,

As you may noticed, DT has recently completed the roll out of the LTE-M network in Germany, while other countries of DT’s footprint continue their rollout activities at the moment. LTE-M is yet another 3GPP LPWA technology, therefore we’d like to provide you with a better understanding on this network, especially when compared to NB-IoT.

Below you will find a summary of key advantages and features:

Like NB-IoT, LTE-M supports lower energy consumption:
• Optimized Chipset-Design focused on relevant radio technologies (e.g. no MIMO)
• Lower Power-Class of modules (20dBm)
• Reduced Signaling and more efficient data transmission
• Low-Power Features (PSM, LP-TAU, eDRX)
Deep indoor coverage is also applicable for LTE-M:
• High Transmission Power Density: radio transmission over a narrow-band carrier with a spectrum bandwidth of only 1,4 MHz
• Coverage Enhancement (CE) / Mode A and Mode B allow for message repetitions
LTE-M has impact on low cost of materials:
• Half-Duplex mode supported
• Unnecessary LTE-Features not supported (such as Carrier Aggregation, Dual Connectivity, Device-to-Device Services)
• Intra-RAT not required (seamless transition between radio technologies, e.g. GSM, 3G, LTE)
• Single antenna needed
Last but not least, hand-over between LTE-M cells is supported (intra-frequency and inter-frequency from 3GPP Rel. 14)

Application of each network technology is highly dependent on the use-cases and therefore should be carefully considered.

Have you been considering LTE-M based solutions for your projects? What of those features are important for your projects and in which of your use-cases LTE-M would be preferable comparing to NB-IoT? Shout out in the comments below and also sign-up if you want to get an early access to LTE-M in IoT Creators ‘Thing’

Stefan de Lange

@Roman-Dyzhyk

LTE-M is a good decision for multiple reasons:

It supports HTTP(S) so I can directly reach my cloud endpoint without the need to build new CoAP/UDP proxies.
Roaming. Virtual MNO’s like ibasis offer great coverage for LTE-M in many countries with a single SIM. This saves a lot of headache for global products. I have yet to see a similar offer for NB-IoT.
Larger data bundles. Generally LTE-M data is cheaper and can be bought in larger quantities. This means I can ocasionally roll out an update without blowing up my data bundle.
It supports most low power features (except RAI) and increased coverage benefits.

The biggest advantage I see today for NB-IoT is ability to use release assist (RAI). RAI has proven to be the biggest energy saver for simple TX only sensors and the fact none of the LTE-M networks or modules supports it is a major drawback for LTE-M. I understand this will be adressed in coming 3GPP releases but those are months if not years away. The fact that RAI is available today for NB-IoT means it will always beat LTE-M in energy consumption.

Roman Dyzhyk

@Stefan-de-Lange, thanks for sharing it! Very much helpful and we will collect some more feedback in following weeks to provide for the interested users LTE-M access, so they can try currently available features

Jim Hunt

After doing some testing, (albeit not here in the UK!) for our use case (electric vehicle charging stations) we’ve come to the conclusion that LTE-M is the way forward for us:

https://www.v2g-evse.com/2018/09/29/what-are-the-top-iot-platform-requirements/

NL and DE are target markets for us, so in the (continuing!) absence of a UK wide LTE-M network testing across the North Sea beckons yet again!

Jim

Roman Dyzhyk

@Jim-Hunt thanks for the comment. What exactly influenced on your conclusion that LTE-M is the way forward: any specific features or requirements for your projects? Interesting to learn more details (if you can share) https://iotcreators.com/en/lte-m-access/

JeroenD

@Stefan-de-Lange IMHO is it possible to do HTTP(S) over NB-IoT, however T-Mobile decided to limit the messages to 512 bytes, use UDP and not to allow connections to the public internet. I think it would be nice to do HTTP(S) over NB-IoT

Jim Hunt

Hi @Roman-Dyzhyk,

For a bit more information see also:

https://www.v2g-evse.com/2018/08/06/department-for-transport-invests-in-v2g-evse/

I sit on the relevant international standards development committees. For this use case (IEC 63110) the committee has specified TCP as a requirement.

Q.E.D?

One “real world” example. How do you perform “over the air” firmware updates using NB-IoT?

Roman Dyzhyk

@JeroenD said in LTE-M or NB-IoT, that is the question…:

HTTP(S) over NB-IoT, however T-Mobile decided to limit the messages to 512 bytes, use UDP and not to allow connections to the public internet. I think it would be nice to do HTTP(S) over NB-IoT

At least you can always do http(s) from IoT Creators portal to your application

Stefan de Lange

@JeroenD I don’t think it’s possible to do TCP/IP over NB-IoT and therefore it’s also not possible to do HTTPS. Atleast not on the networks I have used, maybe it’s supported from the standard point of view. The 512 byte limit is not coming from T-Mobile but from the standard. TCP/IP is a very inefficient protocol for IoT in both data and energy consumption so not a good choice for NB-IoT. It will consume a lot of energy because many bytes are transported and the bitrate is very low. That’s why it’s a better fit for LTE-M

Stefan de Lange

@Roman-Dyzhyk This is okay for UDP, but what about LWM2M?

Roland Baldin

Hi,

I did “normal” TCP/IP MQTT on top of NB-IoT connection with the Quectel BC66. So TCP/IP is possible. But I didn’t try to post a normal HTTP request.

LWM2M is implemented on top of CoAP and UDP. By this it works perfectly on NB-IoT. It is also supported by Quectel BC66. We tested it successfully with Eclipse Leshan server and the Nokia Impact LWM2M server.

Regards, Roland