Narrowband IoT in practice. Advantages. Challenges. Security. Current assessments from more than 12 years of IoT technology experience.

Narrowband IoT in practice. Advantages. Challenges. Security.

Current assessments from more than 12 years of IoT technology experience.

Features.

Narrowband IoT (NB-IoT or LTE Cat-NB1), according to the advertising claim, is a communication technology that will change the world. Indeed, NB-IoT attracts with many interesting features:

  • Minimal energy consumption of the radio operation (among others by special energy saving modes like “PSM”, “LP TAU”, “eDRX”)
  • Low cost modules (medium term between 2€ and 5€)
  • Low cost operation
  • Managed operation of the network (by provider)
  • Possibility to agree on service levels regarding availability of the network
  • Very good coverage due to high penetration even in buildings

Applications.

So far, however, we estimate that few products have been rolled out, as NB-IoT has only been available in the field since (mid/end) 2018. As a result, there is currently only limited support available from standard products (e.g., IoT platforms) in production quality.

NB-IoT is very well suited for simpler IoT applications where latency and bandwidth requirements are low but low cost, indoor use and energy consumption (battery operation for several years) criteria are important.

Network coverage in Europe is now available almost nationwide. However, there are individual providers or regions that are not primarily rolling out NB-IoT, but have opted for (the incompatible technology) LTE CAT-M1 (such as NL (KPN), Scandinavia, and in part also Spain).

Challenges.

As always, the benefits are offset by various challenges in the application of NB-IoT. The main points to be mentioned are:

  1. Challenge of network coverage for international rollout
  • International roaming between providers is not yet available (NB-IoT roaming has been specified, but contracts between providers have not yet been negotiated)
  • Short-term “workarounds” for the (temporary) situation would be to
    • Use of different SIM cards from different providers (is probably not a real alternative in practice with regard to logistics processes…)
    • Some providers offer “internal” roaming with their international subsidiaries (Deutsche Telekom, Vodafone)
  1. Challenge of protocols / reliability / data transmission

First of all, they prefaced that different basic modes of operation can be used in NB-IoT. These are:

  • Non-IP mode: Quasi UDP/IP without IP routing: Disadvantage: Only one destination/source server address is possible (no routing of packets) – This means that usually only one application is possible.
  • IP mode: UDP based protocols (recommendation of the providers)
  • IP mode: TCP would be technically possible in theory, but does not work well in practice due to high latencies (which lead to retransmits of packets) and higher complexity and protocol overhead and is not recommended.

This now gives rise to the following challenges:

  • The (recommended) basic transmission protocols do not have a security mechanism at the connection level, and the individual packets are also limited in length (e.g., approx. 1500 bytes for UDP).
  • standard protocols (such as MQTT-SN, CoAP) cannot be used depending on the requirements of the applications
  • Communication protocols (based on the basic variants mentioned above) must be specially designed and implemented depending on requirements
  • Sending data to devices is not possible out-of-the-box, as there is no standing data “connection” – to enable this, special concepts have to be implemented
  • Latencies in transmission are typically in the range of a few seconds, but can also be up to 30 seconds
  1. Challenge Security
  • The security of the data transmission on the air link is ensured (by the provider).
  • However, the basic standard protocols do not provide security at the transport layer, so the transport between the provider and the cloud application must be protected. Site-2-Site VPN in combination with Private APN or UDP DTLS can be used as measures).
  • The integrated software of the (relatively new) NB-IoT modules is still very buggy in some cases and requires (self-invented) workarounds in many places

Conclusion

This summary is a current snapshot based on our many years of experience in IoT product development. In summary, on the technical side, the promises are realized if one is willing (if the requirements make it necessary) to invest in the development in the area of “productization” (e.g., robustness of transmission) of a project.

In the commercial sector, the promised target costs are not yet being met by the suppliers, be they module manufacturers or providers. An international rollout of products also needs to be carefully considered at present, as the lack of cross-provider roaming represents a significant challenge for OEMs.

Do you have questions, need support in this area or are you looking for a one-stop store for your (IoT) product development? We are happy to be there for you.