5G New Radio (NR) and Narrowband Internetof-Things (NB-IoT) co-existence is a promising technique to improve the spectral efficiency of future cellular networks. In this research project, we study the performance of a 5G NR based multicell network with a number of NB-IoT devices using a dedicated in-band resource block (RB). A unified framework has been developed for maximizing instantaneous throughput and fairness, while considering synchronous RB allocation in the neighboring cells.