Fecha de publicación: 15/01/2020 Fuente: Wipo "IOT" The present invention relates to an Internet of things (IoT) system using an NB-IoT network and a time synchronization method thereof. According to the present invention, the IoT system using NB-IoT network comprises: a network time protocol (NTP) time server for providing standard time; an NTP client for receiving standard time information from the NTP time server; an IoT server including a server RTC for storing the standard time information and calculating a current time; and an IoT terminal including a terminal RTC for receiving time information from the IoT server and calculating the current time. COPYRIGHT KIPO 2020