# Smart Sensor Technologies for IoT
###### Abstract  
The recent development in wireless networks and devices leads to novel services that will utilize wireless communication on a new level. It is possible to see a lot of effort and resources invested to establish new communication networks that will support massive machine-to-machine communication and the Internet of Things (IoT). In these systems, various smart and sensory devices are assumed to be deployed and connected, enabling the streaming of large amounts of data. Smart services represent new trends in mobile services, i.e., a completely new spectrum of context-aware, personalized, and intelligent services and applications. A variety of existing services already utilize information about the position of the user or mobile device. In a lot of applications, the position of mobile devices is achieved thanks to the use of Global Navigation Satellite System (GNSS) chips that are integrated into all modern mobile devices (smartphones). However, GNSS is not always a reliable source of position estimates due to multipath propagation and signal blockage. Moreover, in foreseen IoT applications, the use of GNSS chips integrated into all devices might have a negative impact on their battery life. Therefore, alternative solutions for position estimation should be investigated and implemented in IoT applications. Additionally, smart mobile sensors and devices could be able to fulfill an astonishingly wide range of demands of users and providers. One of the reasons behind the wireless device development is the ever-growing computing power together with the reduction of energy consumption and improved communication capabilities of devices. In order to process a large amount of data from sensors, further investigation of mobile and dynamic cloud computing solutions is also envisioned. Implementation of new services will be with high probability based on the application of cloud services. This, however, produces additional challenges in such areas as management, security, technical solutions, infrastructure modelling, mobile devices support, and many others. This Special Issue of Sensors aims at reporting on some of the recent research efforts on this increasingly important topic. The twelve accepted papers in this issue cover various aspects in Smart Sensor Technologies for IoT. Paper [1] presents the Enhanced Multicast Repair (EM-REP) Fast ReRoute mechanism, which solves several limitations of the legacy M-REP Fast ReRoute mechanism. This means mainly supports for fast reroute in the event of continuous link and node failures throughout the whole network and that the destination host does not have to be directly connected to a network with a router that performs decapsulation, which also reduces the flooding process of M-REP packets in a network with multiple routing areas. The EM-REP mechanism does not require any preparatory calculations, which is effective for IoT devices such as sensors. In the area of WSN and the IoT, it can be used to distribute, for example, urgent messages across the WSN network or to assure the time-critical delivery of important information from sensors to gateways or behind to analytic servers. In [2], the bit-repair (B-REP) Fast ReRoute mechanism is presented. The proposed mechanism provides advanced fast reroute solutions for IoT and IP network infrastructures. B-REP uses a standardized BIER header with a special bit-string field. That allows to use a standardized header and its fields to define an alternative path as well as to transfer user data. The bit-string, in addition, allows to efficiently define an exact alternative FRR path, which can be calculated by the Dijkstra algorithm or even manually defined by the administrator. In [3], the new Multilayered Network Model (MNM) for the 5G mobile network's disrupted infrastructure is introduced. The MNM concept is composed of three independent layers of networks, which are capable of collaboration if disruption of fixed infrastructure occurs.