Internet of Things (IoT) started with the idea of connecting both wireless and wired sensors to the Internet network that can be found in homes, offices, or everywhere. Then, its major contribution was raised by RFID (Radio Frequency Identification) and electronic tags. The IoT makes it possible to connect everything that is connectable, from various objects to "Smart Dust." The concept is simple. However, there are many problems, because "things" are not usually sophisticated enough to handle applications-related communications and processing. Some mobile networks (4G LTE) are used, such as LTE-M (LTE for Machine Type Communication) and NB-IoT (Narrowband IoT), which are LPWA technologies (Low Power Wide Area) standardized by 3GPP. There are also other used LPWA technologies such as LoRa, Sigfox. Nowadays, the number of connected objects becomes to increases very quickly as well as bit-rates and energy consumption. For this, the 5G will provide solutions to this problem, although it manages an Ultra-Dense Network (UDN) requiring a lot of energy. In this paper, we suggest a Call Admission Control (CAC) modeling algorithm for IoT in a New Radio Access (NR 5G), essentially based on minimal energy consumption.