With the continuous development and popularization of IoT technology

human society is entering an era of "all things being interconnected". The new generation of IoT wireless access technology: NB-IoT has advantages of large connection. However

such a large connection still challenges the capacity of NB-IoT network. This paper studies the capacity of the network and proposes some optimization methods under the scenario of highly concurrent users

so as to prepare for a large number of users to access NB-IoT network.