In an embodiment, in order to be adapted for factors, such as dynamic changes of traffic models, and demands of different traffic types for communications, the network device may possibly dynamically configure uplink/downlink transmission directions, which may make that all or part of the time-domain positions of the preconfigured static or semi-static RACH resources are dynamically adjusted into downlink transmission, resulting in that the RACH resources are unable to be normally used for transmission of random access requests. In block 301, in order to ensure normal random access of all UEs to be randomly accessed and reduce interference to other UEs, the network device may explicitly or implicitly indicate the dynamic scheduling information of the RACH resources via the control signaling (such as a PDCCH, and an NR-PDCCH), so that after selecting the RACH resources, the UE determines whether the RACH resources are available according to a situation of receiving the control signaling (whether the control signaling is received), or according to the dynamic scheduling information of the RACH resources (in a case where the control signaling is received), by monitoring the control signaling corresponding to the selected RACH resources. “The control signaling” here is a collective name, and contains all contents executing a control function, such as a signal, a channel, and a message, that is, in some implementations, the control signaling may also be referred to as a control channel or a control signal or a control message, which are collectively referred to as control signaling, for the convenience of description.

In an embodiment, the above UE to be randomly accessed may be in RRC_IDLE, RRC_CONNECTED states; wherein, the RRC_CONNECTED state includes an RRC_ACTIVE state, and an RRC_INACTIVE state, etc.