A Method and Apparatus for performing small data transmission is provided. The method includes transmitting UECapabilityInformation to the base station, The UECapabilityInformation includes type 1 SDT support information and type 2 SDT support information, transmitting a message containing the UE NETWORK CAPACITY to the AMF, Specific bits in the UE NETWORK CAPABILITY indicate whether RRC CONNECTION RESUME3 is supported, receiving an RRCRelease from the base station, The RRCRelease comprises a SuspendConfig, In response to receiving said RRCRelease message, entering the RRC_INACTIVE state and performs cell selection, monitoring the paging channel in the selected cell, and initiating RRC CONNECTION RESUME3 or performing the first set of actions upon receiving a first paging message or a third paging message.