The DRX discontinuous reception UE stops monitoring the PDCCH channel for a period of time. There are two types of DRX: idle DRX \ active DRX, and idle DRX means discontinuous reception when UE is in idle state. Because the UE has no RRC connection and user-specific resources when it is idle, this is mainly to monitor the call channel and broadcast channel. As long as a fixed period is defined, the purpose of discontinuous reception can be achieved. However, if the UE wants to monitor the user data channel, it must first enter the connected state from the idle state. The other is active DRX, that is, DRX in which the UE is in RRC connection state, which can optimize the system resource allocation and, more importantly, save the power of the mobile phone without having to let the mobile phone enter RRC_IDLE mode to achieve this goal. For example, some non-real-time applications, such as web browsing and instant messaging, will always exist for some time. Mobile phones do not need to constantly monitor downlink data and related processing, so DRX can be applied to such a situation. In addition, since there is still RRC connection in this state, the speed of UE switching to the support state is very fast.