Communications protocols for the Internet of Things
The quantity of devices connected to the Internet exceeds the population of people on Earth. That’s right—there are more devices tapping into the Internet than people on Earth to use them. Different sources predict that by 2020, wireless sensors and other types of wireless network nodes (such as actuators) will account for the majority (60 percent) of the total installed base of Internet of Things (IoT) devices.
Autonomous sensors will play a large part in those predictions. These sensors autonomously execute their functions in the environment in which they have been deployed. They are wireless, and their most distinctive characteristic is that they are self-powered while still being capable of monitoring the environment and transmitting data. Such devices range from simple detectors that trigger an alarm signal if the sensor passes a measurement threshold, to monitoring systems that collect data regarding different products or processes.
Autonomous sensors can potentially be deployed everywhere, though there are usually constraints on the power supply of such devices, so the communication technology must be carefully selected. Most of these sensors employ low-power-consumption wireless protocols, such as ZigBee or Bluetooth Low Energy (BLE). ZigBee is a protocol specifically developed for mesh communication—each sensing device can transmit data either directly to the acquisition module, or to another nearly ZigBee-based sensing device, which in turn will transmit both devices’ data to the acquisition module. When they are deployed in urban areas, it is also typical to implement Wi-Fi-based devices, taking advantage of the Wi-Fi coverage associated with these places. A new, interesting trend with sensor devices connected to the IoT involves using smartphones to serve as a bridge between the sensors and the cloud. A force still to be reckoned with is that many citizens are eager to help their communities by installing smartphone applications that provide such a bridge to data, as long the information is to be used for something they believe in.