IoT - or Internet of Things - is all about connecting physical objects in our environment to that ever pervasive Internet - where we can combine the information gleaned from these objects with fantastic new business models. In this post I'll talk about the how - what technologies are most commonly used to connect things. In other posts I'll talk about the why.
First of all, these things need to connect without wires, and they do that with radio frequency - or RF - technology. There are two fundamental technology "stacks" used to do this, based on the type of RF spectrum:
1. Licensed spectrum, exclusively utilized through cellular technology which we are all familiar with. Cellular technology has been the connectivity workhorse for any connected object outside of the home, office or factory.
2. Unlicensed spectrum, which offers a connectivity playground for just about anyone to play in. Because of the low access barriers, smart people have devised many, many ways to connect devices in the unlicensed spectrum playground.
In the licensed spectrum arena, we are mainly dealing with connection technologies such as (listed in chronological order of rollout) 2G, 3G, 4G, LTE, Cat-M1 and NB-IoT. The latter technology is specifically designed for connecting embedded sensors with low-bandwidth connection requirements and is being rolled out now.
When we look at the unlicensed spectrum, we have a number of technologies to choose from with various energy / range / bandwidth trade-offs. From shorter range higher bandwidth all the way to long range low bandwidth we have WiFi, Bluetooth, Zigbee, Z-Wave, 6LoWPAN, Sigfox, LoRaWAN, Ingenu, Weightless, and others.
In the unlicensed spectrum we also have two main bands globally that devices can communicate in - namely the 2.4 GHz ISM ("Industrial Scientific Medical") band and the sub-GHz ISM band. Around the world the sub-GHz band is a little less uniform, and regulated slightly differently in each jurisdiction, but is the chosen band for any of the long range communication technologies. Generally, 2.4 GHz technologies focus on in-building short range higher bandwidth applications, while the sub-GHz technologies cover anything that is "smart city", outdoors, or mobile.
WiFi, Bluetooth, Zigbee, Z-Wave are short range 2.4 GHz technologies; 6LoWPAN (also known as Thread) is often found in 2.4 GHz devices but is finding applications in medium range solutions employing sub-GHz frequencies; and Sigfox, LoRaWAN, Ingenu, Weightless are exclusively designed to work with sub-GHz radio chipsets.
In another post we'll look at the protocol stacks commonly used to connect IoT devices to the Internet.