An overview of IoT connectivity with definition, key technologies and a comparison of the main technologies.
IoT connectivity is the means by which an IoT device, which can be anything from a simple sensor in a factory to a self-driving vehicle and encompasses applications from streetlights to robots, connects to the cloud, other devices and integration points such as IoT gateways. IoT connectivity is essential because it enables the I of IoT, without it, devices are just things. It is the IoT connectivity that brings value from IoT by communicating their data to enable action to be taken, services to be delivered and revenue generated.
The fragmented nature of IoT deployments mean there are a large number of IoT connectivity standards for organizations to choose from. How to connect to IoT is one of the most important decisions when it comes to IoT. IoT connectivity should be selected based on careful assessment of each deployment’s characteristics. For some very high speed, ultra-low latency connectivity is required. This may lead to adoption of 5G or 4G cellular IoT connectivity but this decision must be balanced against the likely cost and the power usage these technologies require. For some simpler deployments, low speed connections that are not always on can be ideal, requiring smaller batteries and delivering IoT connectivity cost effectively.
The three main technical requirements for any enterprise looking into Internet of Things connectivity are coverage, energy efficiency and data rate. No single technology can excel in all these aspects, as these are trade-offs every radio technology faces. In addition, organizations should consider where their IoT offerings will be provided. If you need global IoT connectivity you should adopt a connectivity technology that is available worldwide.
It is not possible to provide a comprehensive IoT connectivity comparison because there are significant variables to consider but, as the diagram below illustrates, traditional cellular technologies’ strengths lie in data rate (mostly 4G, 5G) and range with complex designs optimized for mass consumer voice and data service; short range technologies like Bluetooth Low Energy (BLE) and ZigBee focus on data rate and battery life at the expense of connection range; LPWA technologies such as NB-IoT, provide superior battery life and coverage, but low data rate on the downside.
The energy efficiency of a connectivity technology has a significant impact on the lifetime or the maintenance cycle of IoT devices relying on battery or energy harvesting and is dependent on range, topology and complexity of the connectivity technology. The overall energy consumption of the device also depends on the usage of the application, such as the frequency and duration of message transmission.
Short range technologies such as ZigBee rely on mesh topology to forward messages from one device to another over multiple hops. That way ZigBee can extend its coverage but may deplete batteries more quickly as an individual device must constantly listen and be ready to relay messages. Wide area technologies, such as 2G, rely instead on star topology and keep most of the intelligence and complexity at the base station where power supply is not a limiting factor. LPWA technologies, such as NB-IoT, further reduce the energy consumption by stripping down the signaling protocol and reducing the amount of overhead to the bare minimum, thus enabling longer battery life.
Data rate requirements for IoT applications vary from hundreds of bit per second (bps) for utility metering to several megabits per second (Mbps) for video surveillance on the uplink. Furthermore, with the arrival of more sophisticated IoT applications, end devices need to be able to receive data packages with sufficiently high speeds. Ensuring they have high enough downlink capabilities to support this is essential.
The various IoT technologies exhibit different strengths and weaknesses, depending on the technical, commercial and ecosystem angle. This comparison illustrates the strengths and weaknesses of the major technologies.