I. Introduction
IoT refers to the interconnection between various objects that can communicate among each other with minimal need for human supervision. Due to the rapid advances in the field of underlying technologies, IoT has tremendous opportunities in several different areas such as security, asset tracking, remote monitoring, metering (gas, water and electric) and smart grid to name a few. In order to meet the requirements set forth by such applications, the 3GPP (Third Generation Partnership Project) has introduced a new radio access technology called NB-IoT (Narrowband Internet of Things) which provides extended coverage, high capacity, reduced device processing complexity and long battery lifetime.