Abstract: The present invention relates to a wireless communication system. More specifically, the present invention relates to a method and a device for handling for Bandwidth Part operation in wireless communication system, the method comprising: starting a timer related to a downlink (DL) bandwidth part (BWP), when an active BWP for a serving cell is switched to the DL BWP; wherein DL semi-persistent scheduling (SPS) resources are configured on the DL BWP and uplink (UL) SPS resources are configured on a UL BWP related with the DL BWP; transmitting UL data on one of the UL SPS resources or receiving DL data on one of the DL SPS resources; and restarting the timer related to the DL BWP when the UL data is transmitted on the UL SPS resource or the DL data is received in the DL SPS resource.

Abstract: A method of performing, by a user equipment (UE), wireless communication using a serving cell in a wireless communication system is provided. The method includes: starting a deactivation timer associated with the serving cell, the deactivation timer relating to a duration of time after which the serving cell is deactivated; determining whether there is an uplink (UL) grant or a downlink (DL) assignment for the serving cell in a time unit; based on a determination that there is an UL grant or a DL assignment, determining whether a data unit is transmitted on the UL grant or is received on the DL assignment; based on a determination that the data unit is transmitted on the UL grant or is received on the DL assignment: restarting the deactivation timer associated with the serving cell; and transmitting the data unit on the UL grant or receiving the data unit on the DL assignment.

Abstract: A radio link control (RLC) entity of a transmitting device receives a first RLC service data unit (SDU) from an upper layer of the transmitting device. If the RLC entity receives, from the upper layer, a discard indication to discard the first RLC SDU, the RLC entity checks whether the first RLC SDU has been submitted to a lower layer of the transmitting device. The RLC entity discards the first RLC SDU if neither the first RLC SDU nor a segment of the first RLC SDU has been submitted to the lower layer.