Without connectivity, there is no Internet of Things. Only a few years back, getting an IoT device online was both complicated and costly. However, the drop in price and general availability of internet-enabled microcontrollers have spawned a vast number of IoT solutions in a wide range of business verticals. Applications range from self-driving cars with huge amounts of data being sent continuously over high-speed networks, to miniature sensor modules sending a few bits of data a few times a week and lasting a decade on a small battery.
One might think that a standard WiFi connection would be the best for an IoT application. After all, WiFi seems to be ubiquitous today, offering stable connections with data throughput in the gigabit range. However, WiFi networks suffer from a severe drawback: the reach of a WiFi network is very limited (under ideal conditions around 100 m). An alternative could be Bluetooth Low Energy (BLE). Unfortunately, BLE has pretty much the same limitations regarding reach as WiFi: about 100 m under ideal conditions. As we will see, there are also other options like Sigfox and LoRaWAN, but these offer very slow data transfer speeds and long latencies. So what is the alternative?
Cellular IoT uses existing cellular networks to connect physical devices to the Internet, i.e., the same type of networks our smartphones use to communicate. Cellular IoT relies on 2G, 3G, 4G, and more recently also 5G and Low Power Wide Area Networks (LPWAN) technologies such as LTE-M and NB-IoT to transmit and receive data. Cellular IoT is one of the most reliable and accessible ways to enable Internet connectivity for manufacturers building IoT devices. These cellular networks are available almost everywhere and there are some very nice advantages in using them: