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Cellular networks provide the backbone for much of what we know and love, allowing us to access the internet, send messages, and connect with friends. In addition to the personal benefits we're all familiar with, cellular networks also serve a critical role in many Internet of Things applications.
As we’ve discussed in previous chapters, there will always be a tradeoff between power consumption, range, and bandwidth. Cellular connectivity has been focused on range and bandwidth at the expense of power consumption, meaning that it can send lots of data over long distance but drains battery rather quickly.
This is fine for devices that are connected to an electricity source or that can be recharged often (i.e. your phone), but a no-go when it comes to IoT applications that require remote sensors/devices to last months or years on battery.
As such, cellular connectivity is usually reserved for backhaul (i.e. a gateway might use LPWAN to talk to all the sensors/devices but use cellular to connect to the cloud and pass along that data) or for sensors/devices that need to send a lot of data and/or don’t have concerns about battery life.
However, that's not the full story when it comes to cellular. You've probably heard names like 2G, 3G, and 4G (which refer to different generations of cellular networks), but new cellular technologies like Cat-1, LTE-M, and NB-IoT are aimed specifically at IoT applications. As with LPWANs, we won’t go into the details of these cellular technologies, but the main takeaway is that they are either upgrades to existing networks or new infrastructure entirely, and all aimed specifically at reducing data costs per sensor/device and power requirements.
Some of these cellular technologies are currently available, and others are promised but yet to come. This also includes 5G, which will also have significant implications for IoT applications and enable high-bandwidth, high-speed applications like Ultra-HD (4K) streaming, self-driving car connectivity, or VR/AR applications.
There’s also discussion around supporting IoT devices with 5G-IoT networks. However, all these are just speculations as 3GPP (the standards organization for cellular technologies)) will finalize the specifications in 2019. The commercial rollout target year is 2020.
It’s important to understand that these different options do not have to be mutually exclusive. This extends to other connectivity options as well, like the LPWANs.
IoT covers a broad spectrum of applications. Sometimes you need high bandwidth, like with real-time surveillance. For asset tracking, data throughput is small, but there are inevitably many handovers as objects move. Smart meters and many smart city use-cases require small data transfer once or twice a day. This means that no one technology (even 5G) may fit the specific needs of your particular IoT solution and may use a combination.