MDPI SI-IoT-ASI 2020 : Special Issue "Internet of Things: Challenges, Developments, and Perspectives"

Fifteen years ago, the Internet Engineering Task Force (IETF) created the 6LoWPAN working group. That was the first step to develop a full and open protocol architecture for the Internet of Things (IoT), which enables end-to-end communication for IoT devices by relying on the IPv6 protocol. Today, the IETF architecture is available, but it also continues to evolve in order to accommodate new link layer technologies like Low-Power Wide-Area Networks (LPWANs). Several other protocol architectures exist, usually designed with a particular scenario in mind, like smart home or Industrial IoT (IIoT). This leads to market fragmentation and interoperability problems. In addition, many IoT solutions have become dependent on cloud-based platforms. While the main purpose of such platforms is data storage and processing, they also help in providing remote connectivity to IoT devices behind NATs. The cloud introduces privacy concerns and also delays in processing data and triggering actions. These limitations are being overcome by a new wave of IoT solutions based on edge computing. Currently, data processing can be done within the radio access network of telecom operators on the premises of enterprises and campuses, at the border between IT and OT in the industry, or by IoT devices themselves. This evolution is being accompanied by the advent of new wireless technologies and network paradigms, such as 5G or LEO constellations of satellites. Finally, the energy needs of IoT devices should have to be reconsidered. A trade-off appears between the ever desirable power consumption reduction (e.g., in order to increase lifetime or reduce OPEX and CO2 emissions) and the need for more processing power and latency reduction, imposed by the edge computing approach.