The previous blog post discussed NB-IoT, and why, although it is a great IoT wireless solution that leverages massive infrastructure and technical momentum, it may not be the best choice in certain locations or in applications that demand great flexibility.
There are three more situations where other LPWAN technologies may be superior. These situations involve considerations in the areas of security, cost, and application requirements.
Security: Because it uses existing cellular infrastructure, NB-IoT comes with security built-in. However, as a TCP/IP-based technology, it is susceptible to denial of service attacks. Sensors that communicate with their gateway without using IP addresses are not susceptible to these attacks. Furthermore, NB-IoT is inappropriate for applications where data must be kept in-house, on physically secured servers. Storing information on remote servers adds an additional layer of risk. Finally, you may want extra encryption for your data, especially if it is highly proprietary or associated with national defense or critical infrastructure. LoRaWAN has three layers of keyed encryption, which makes it exceptionally secure.
Cost: A second area where NB-IoT may not be ideal is cost. Depending on the cellular service provider, you are likely to encounter monthly device costs, SIM card costs, and data costs. For example, Verizon charges $2 per month for up to 200 kB of data. Prices do decrease dramatically for large data users; for example, Verizon charges less than $10 per GB. Where the volume of data is large, NB-IoT shines; for applications with many sensors that generate small amounts of data, NB-IoT can be a very expensive proposition.
In addition to the monthly costs, you may have costs associated with the IoT device development process. These include the expenses associated with PTCRB (PCS Type Certification Review Board) certification and with carrier certification costs (tens of thousands of dollars per carrier). These certifications are critical to the success of NB-IoT; flawed devices on the cellular network could generate several types of problems, including slowing down the overall flow of data.
Finally, you may have specific requirements for your application that make NB-IoT either impossible or impractical. For example, what if you have a massive array of sensors? A WAVIoT solution can handle more than two 2 million nodes per gateway, far more than NB-IoT. Perhaps you need a link budget larger than 164 dB, or you need data rates of up to 1 Mbps, such as LTE Cat-M1 provides.
Application requirements: Perhaps you have a high-mobility application that must be able to move from one cell to another in milliseconds when requested by the network (again, LTE Cat-M1 is a good choice here). Or perhaps your application is very specific, and you want to take advantage of work others have already done. One example would be to use Wireless M-Bus for smart utility metering. The fact that the system is optimized for a single application makes it very efficient and robust for its intended purpose, although it does lack many features that would be common with a general purpose IoT LPWAN solution. Another example would be a solution where you want to take advantage of an artificial intelligence (AI) solution such as IBM's Watson, using IBM Watson IoT Platform.
Although there are situations where NB-IoT may not be the best choice, it is a powerful solution for many IoT applications. However, it is important to consider your application’s location, requirements, security needs, and budget before selecting an LPWAN solution for the IoT.