NB-IoT: A Candidate Technology for Massive IoT in the 5G Era

The existing mobile network infrastructure is currently optimized to support the Narrow-Band Internet of Things (NB-IoT), which is meant to provide numerous services in poor coverage areas, with ultra-low power consumption. The question that arises is whether (and to what extent) NB-IoT can meet the requirement for massive Machine Type Communications (mMTC) in the 5G era. In view of this, we study coverage enhancement in NB-IoT. We describe the subframe structure for various physical channels of NB-IoT and explain the repetition mechanism used for downlink transmissions in poor coverage areas. Focusing on optimizing this mechanism, we analyze how the latency and user blockage can be reduced by a proper selection of the downlink radio resources.