This module focuses on how we can interconnect a large number of IoT devices, especially in a wide-area deployment environment that may span several kilometers. In general, one may utilize traditional WiFi or cellular based connectivity technologies, through which we already connect our regular devices such as notebooks or mobile phones. However, IoT devices and applications have special needs and requirements, giving rise to specific communication technologies designed for the lightweight and efficient connectivity of IoT entities.
As depicted in Figure 1.1, IoT deployments can be viewed as a layered architecture that interconnects the physical world (observed through IoT devices/sensors) with the digital world of IoT applications and services. The device connectivity layer, which is the focus of this module, plays a pivotal role by establishing the links for exchanging data and commands among the IoT entities.
¶ 1.1 IoT Application Types: “Massive IoT” vs. “Critical IoT”
When we think of IoT scenarios and application requirements, it is actually a very wide spectrum. 5G specifications by the standardization organization 3GPP introduces three different service types: Enhanced Mobile Broadband (eMBB), Massive Machine-Type Communications (mMTC) and Ultra-Reliable and Low-Latency Communications (URLLC). These are depicted as the corners of a triangle, where various services and applications are placed within the triangle. If we map this to the IoT domain, we can name two distinct types: “Massive IoT” (bottom-left) and “Critical IoT” (bottom-right).
On the bottom left side of the triangle, we have a very large number of low-cost, low-energy devices, each producing very small amounts of data. On the bottom right side, we have complex intelligent devices that require very reliable and near real-time communications for critical processes, such as connected and automated driving and e-health scenarios. Our focus in this module will be on the “Massive IoT” case, since it requires new types of communication technologies for IoT.