Narrow Band Internet of Things（NB-IoT）is a promising low-power Wide-Area Network（WAN）technology.Communicating a small amount of data over a long period of time is one of the goals in the NB-IoT

which is one of the key features in the IoT application.Some research groups have defined several NB-IoT standards

such as low power consumption

wide coverage

large capacity

and low cost.Compared with the conventional wireless communication protocol

NB-IoT spectrum bandwidth is only 180 kHz.Therefore

how to use resources or spectrum more effectively（i.e.

resource allocation and scheduling）is a key issue.In this paper

we first design the upper layer communication of the physical layer

especially the uplink scheduling.Then

we discuss the resource allocation of NB-IoT in the case of good delay.Finally

we discuss some open problems and their corresponding solutions

which ensure the reliability of signal transmission.