IEEE Communications Magazine • February 2017 68 GUEST EDITORIAL T he Internet of Things (IoT) is a proposed development of the Internet in which everyday objects are equipped with electronics, software, sensors, and network con- nectivity, allowing them to send and receive data through the Internet. Formally, IEEE has described IoT as “a network of items — each embedded with sensors — which are con- nected to the Internet.” From a practical perspective, the main difference between IoT and the existing network par- adigms is that every element of IoT is able to collect and exchange data through the network without or with minimal human intervention. This opens a whole new set of interest- ing research challenges for future communication networks, in terms of overall system design, software implementation, data management, and service deployment. IoT integrates different technologies and has a non-neg- ligible impact on a variety of applications in different fields. With such capabilities, IoT has also opened interesting business opportunities in practically relevant fields such as healthcare, transportation, logistics, and manufacturing. This Feature Topic focuses on the practical aspects of IoT in 5G networks. The aim is to pave the way toward the identifi- cation of the bridge between recent theoretical findings/ analytical solutions and future industrial challenges/busi- ness opportunities. Our Call for Papers attracted a number of submissions. After a thorough review process, the five papers that were best aligned with the aforementioned goal were chosen for publication. The article “Latency Critical IoT Applications in 5G: Per- spective on the Design of Radio Interface and Network Architecture” authored by P. Schulz et al. focuses on laten- cy critical IoT applications, including factory automation, smart grids, and intelligent transportation systems. The arti- cle then discusses related requirements such as delay, reli- ability, data size, device density, and communication range. Solutions for radio interface and network architecture to meet such requirements and address the challenges, such as radio resource management, fast uplink access, transmis- sion time shortening, and waveform design, are proposed. The article finally discusses the advantages brought by the new architecture in terms of flexibility and potential to meet all requirements. The article “Effects of Heterogeneous Mobility on D2D- and Drone-Assisted Mission-Critical MTC in 5G” authored by A. Orsino et al. considers mission-critical machine type communications in LTE to support IoT applications with a variety of requirements in terms of low power, high reliability, and low latency. The article examines the impacts of mobility and heterogeneity of users and devices. Finally, the article presents numerical results to corroborate intuitions, insights, and proposals, and is concluded by a discussion on future research directions. The article “IoT Connectivity in Radar Bands: A Shared Access Model Based on Spectrum Measurements” authored by Z. Khan et al. introduces a shared access framework to support IoT connectivity. The framework is developed based on the measurement results for the spectrum usage patterns and signal characteristics of ground-based fixed rotating radar systems deployed in Oulu, Finland. Subsequently, the article presents a radio environment map architecture com- posed of an information and measurement resource mod- ule, a database module, gateways, and device connectivity for the framework. Finally, the article highlights the benefits brought by the adoption of such a design, and outlines future research and development directions. The article “Efficient IoT Gateway over 5G Wireless: A New Design with Prototype and Implementation Results” authored by N. Saxena et al. introduces the design and development of gateways to support IoT devices’ commu- nications. The gateways are able to receive IoT data traffic from the devices and provide classification and compression of delay-tolerant traffic. Then the gateways forward the traffic to a 5G cloud radio access network (C-RAN), which includes virtual base stations for processing. A prototype and testbed development based on off-the-shelf hardware and software, characterized by flexibility and suitability for real IoT applica- tions, is presented. The article “Wireless Caching for 5G Networks: From The- ory to Implementation” authored by Y. Fadlallah et al. dis- cusses the integration of wireless edge caching and coded multicast transmissions in 5G networks, with potential to sup- port IoT applications. First, theoretical analyses of the cach- ing-aided coded multicast technique are performed to assess PRACTICAL PERSPECTIVES ON IOT IN 5G NETWORKS: FROM THEORY TO INDUSTRIAL CHALLENGES AND BUSINESS OPPORTUNITIES Marco Maso Dong In Kim Ariton Xhafa Michele Zorzi Ashutosh Dutta Dusit Niyato