Method and apparatus for data transfer in RRC_INACTIVE state in mobile wireless communication system

A method performed by a terminal, the method comprising:

• transmitting, by the terminal, a UECapabilityInformation to a base station, the UECapabilityInformation including a first capability information and one or more second capability information, wherein the first capability information indicates whether the terminal supports RRC_INACTIVE, and the second capability information indicates whether the terminal supports transmission of data in RRC_INACTIVE state;
• receiving, by the terminal, a RRCRelease, the RRCRelease including a first information for second resume procedure and a timerValue1, wherein the first information for second resume procedure includes a Signaling Radio Bearer2 (SRB2) indicator and a Data Radio Bearer (DRB) list;
• starting, by the terminal, a timer with a timer value set to the timerValue1;
• receiving, by the terminal, a system information, the system information including a first threshold and a second threshold, wherein the first threshold is related to a reference signal received power and the second threshold is related to a data volume;
• initiating, by the terminal, a first resume procedure or a second resume procedure;
• stopping, by the terminal, the timer after restoring a configuration stored in UE Inactive Access Stratum (AS) context in case that the second resume procedure was initiated;
• and
• stopping, by the terminal, the timer before restoring the configuration stored in UE Inactive AS contex in case that the first resume procedure was initiated,
• wherein the first resume procedure is initiated in case that the timer expires,
• wherein suspended RRC connection is resumed via the first resume procedure, and
• wherein data transmission and data reception are performed in RRC_INACTIVE state during the second resume procedure.