ive Internet of Things (IoT) is an interconnected network of physical objects (devices) that interact with humans or other physical objects and systems, where communications among machines can be performed without human interaction or supervision. The IoT is considered a driving force behind recent improvements in wireless communications technologies such as 3GPP LTE and NR in order to satisfy the stringent requirements of massive machine- type communication (mMTC) diverse applications. The IoT use cases have been divided into two main categories: massive IoT and mission-critical IoT. The massive IoT aims to connect a very large number of devices, for example, remote indoor or outdoor sensors, to the cloud-based control and monitoring systems, where the main requirements are low cost, low power consumption, good coverage, and architectural scalability. In contrast, mission- critical IoT applications, for example, remote healthcare, remote traffic monitoring/control, and industrial control, require very high availability and reliability as well as very low latency. Narrowband IoT (NB-IoT) is an LTE-based cellular radio access technology that provides low-power wide-area (LPWA) connectivity in licensed spectrum. There are several short-range technologies in unlicensed spectrum, including Bluetooth, ZigBee, 2 etc., and other LPWA technologies, including SigFox, 3 LoRaWAN,4 etc., which have been devel- oped to address vertically different use cases of industrial IoT. The 3GPP design targets for Rel-13 were long device battery life, low device complexity to ensure low cost, support for massive number of devices, and coverage enhancements to be able to reach devices in base- ments and other inaccessible locations. The NB-IoT is optimized for machine-type traffic. It was designed to be as simple as possible in order to reduce device complexity and to mini- mize power consumption. Indoor penetration and rural coverage are among the key require- ments for the IoT applications, and support of operation in sub-1 GHz bands i