A method performed by a user equipment, UE, in a mobile communication system, the method comprising: receiving (5d-05, 5e-05), from a source base station, a UE capability enquiry message; transmitting (5d-10, 5e-10), to the source base station, UE capability information including information indicating whether the UE supports a handover without random access; receiving (5d-30, 5e-30), from the source base station, a radio resource control, RRC, connection reconfiguration message for a handover command, the RRC connection reconfiguration message including information indicating whether a random access procedure for a target base station is skipped and a timer value; in case (5d-30) that the RRC connection reconfiguration message includes uplink resource information, transmitting (5d-50) an RRC connection reconfiguration complete message to the target base station based on the uplink resource information; in case (5e-30) that the RRC connection reconfiguration message does not include the uplink resource information: monitoring (5e-55) a physical downlink control channel, PDCCH, of the target base station; upon receiving (5e-55) control information on the PDCCH, transmitting (5e-60) the RRC connection reconfiguration complete message based on uplink resource information included in the control information; and in case that no control information is received on the PDCCH before the timer value expires, performing cell selection for determining a suitable cell and performing the random access procedure to the suitable cell. receiving (5d-05, 5e-05), from a source base station, a UE capability enquiry message; transmitting (5d-10, 5e-10), to the source base station, UE capability information including information indicating whether the UE supports a handover without random access; receiving (5d-30, 5e-30), from the source base station, a radio resource control, RRC, connection reconfiguration message for a handover command, the RRC connection reconfiguration message including information indicating whether a random access procedure for a target base station is skipped and a timer value; in case (5d-30) that the RRC connection reconfiguration message includes uplink resource information, transmitting (5d-50) an RRC connection reconfiguration complete message to the target base station based on the uplink resource information; in case (5e-30) that the RRC connection reconfiguration message does not include the uplink resource information: monitoring (5e-55) a physical downlink control channel, PDCCH, of the target base station; upon receiving (5e-55) control information on the PDCCH, transmitting (5e-60) the RRC connection reconfiguration complete message based on uplink resource information included in the control information; and in case that no control information is received on the PDCCH before the timer value expires, monitoring (5e-55) a physical downlink control channel, PDCCH, of the target base station; upon receiving (5e-55) control information on the PDCCH, transmitting (5e-60) the RRC connection reconfiguration complete message based on uplink resource information included in the control information; and in case that no control information is received on the PDCCH before the timer value expires, performing cell selection for determining a suitable cell and performing the random access procedure to the suitable cell.