Abstract: The present invention relates to a method of transmitting a data unit by a transmitter in a wireless communication system. In particular, the method includes the steps of: generating the data unit including a payload; and transmitting the data unit to a receiver, wherein the data unit includes a header compression type field indicating at least one of a first type header compression algorithm and a second type header compression algorithm is applied to a header of the payload.

Abstract: The present invention relates to a wireless communication system. More specifically, the present invention relates to a method and a device for transmitting lossless data packet based on QoS framework in wireless communication system, the method comprising: starting a timer for a first QoS flow when a DRB which is mapped to the first QoS flow is changed from a first DRB to a second DRB; delivering packets of the first QoS flow received from the first DRB to an upper layer while the timer is running; when the timer expires, starting to deliver the packets of the first QoS flow received from the second DRB while stopping the delivering packets of the first QoS flow received from the first DRB.

Abstract: The present invention relates to a method for processing signals by a node in a wireless communication system. In particular, the method includes receiving a radio bearer (RB) configuration message from a network; and configuring a radio bearer between a radio link control (RLC) entity of the node and a peer RLC entity using the RB configuration message, wherein the RB configuration message includes information about that the peer RLC entity operates with a different RLC mode from a RLC entity of the node.

Abstract: The present invention relates to a wireless communication system. More specifically, the present invention relates to a method and a device for transmitting lossless data packet based on QoS framework in wireless communication system, the method comprising: starting a timer for a first QoS flow when a DRB which is mapped to the first QoS flow is changed from a first DRB to a second DRB; delivering packets of the first QoS flow received from the first DRB to an upper layer while the timer is running; when the timer expires, starting to deliver the packets of the first QoS flow received from the second DRB while stopping the delivering packets of the first QoS flow received from the first DRB.

Abstract: A method for processing a data unit by a Packet Data Convergence Protocol (PDCP) entity of a user equipment includes configuring three or more Radio Link Control (RLC) entities with the PDCP entity; activating a first duplication mode for first and second RLC entities among the three or more RLC entities; providing the data unit to the first and second RLC entities by duplicating the data unit; receiving a duplication mode change command from a network; changing the first duplication mode to a second duplication mode for the first RLC entity and a third RLC entity; and providing the data unit to the first and third RLC entities by duplicating the data unit, wherein the first and second RLC entities is configured with a first Media Access Control (MAC) entity, and wherein the third RLC entity is configured with a second MAC entity.

Abstract: A method for transmitting a packet by a Packet Data Convergence Protocol (PDCP) entity of a user equipment in a wireless communication system is disclosed. The method comprises delivering a packet to a first Radio Link Control (RLC) entity; and when a radio link failure (RLF) related to the first RLC entity is detected, retransmitting the packet through a second RLC entity if acknowledgement information of the packet is not received from the first RLC entity.

Abstract: The present invention relates to a wireless communication system. More specifically, the present invention relates to a method and a device for performing a re-establishment of PDCP entity associated with UM RLC entity in wireless communication system, the method comprising: when a re-establishment of a Packet Data Convergence Protocol (PDCP) entity is triggered, stopping and resetting, by the PDCP entity, a reordering timer of the PDCP entity if the reordering timer of the PDCP entity is running; and delivering, by the PDCP entity, all stored PDCP Service Data Unit (SDU) to upper layers in ascending order of associated COUNT values.

Abstract: The present invention relates to a wireless communication system. More specifically, the present invention relates to a method and a device for transmitting TCP ACK packet in wireless communication system, the method comprising: receiving a packet with a first QoS flow ID for a PDU session from an upper layer, wherein a first DRB for transmitting only TCP ACK packet is configured for the PDU session; checking whether or not the received packet is a TCP ACK packet; and if the received packet is the TCP ACK packet, delivering a PDU including the received packet to a lower layer via the first DRB, wherein the first QoS flow ID of the received packet is associated with a second DRB according to QoS flow to DRB mapping rule of the PDU session.

Abstract: The present invention relates to a method for receiving packets by a user equipment (UE) in a wireless communication system. In particular, the method includes receiving a handover command including security information; establishing a connection with a second network; based on detecting a connection failure with the second network, deriving a security key for a first network based on the security information; performing a PDCP re-establishment for one or more radio bearers of the first network based on the security key for the first network; and reporting, to the first network, the connection failure with the second network.

Abstract: The present disclosure relates to a method of receiving a data unit by a receiver in a wireless communication system. In particular, the method includes the steps of: receiving the data unit including a payload; and decompressing a header of the payload based on both a first type header compression algorithm and a second type header compression algorithm.

Abstract: The present invention relates to a method for receiving packets by a decompressor in a wireless communication system. In particular, the method includes receiving a full header packet from a compressor, wherein the full header packet includes a context identifier (CID) and a header context; establishing the header context; transmitting a feedback packet including the CID; starting a timer related to the CID; and based on not receiving a compressed header packet related to the CID until expiration of the timer, retransmitting the feedback packet including the CID to the compressor.

Abstract: Provided is a method for changing, by a user equipment (UE), packet data convergence protocol (PDCP) version. The method may include: receiving a security mode command message, which includes a first security algorithm configuration for a PDCP of a first system and a second security algorithm configuration for a PDCP of a second system, from a base station (BS); deriving a first security key for the PDCP of the first system, based on the first security algorithm configuration; when the security mode command message passes an integrity protection check based on the first security key, changing the PDCP version from the PDCP of the first system to the PDCP of the second system; deriving a second security key for the PDCP of the second system, based on the second security algorithm configuration; and transmitting a security mode complete message, based on the second security key, to the BS.

Abstract: The present invention relates to a method for transmitting a packet by a Packet Data Convergence Protocol (PDCP) layer entity of a UE in a wireless communication system. In particular, the method includes submitting a packet periodically to a lower layer if a type of the packet is one of specific types, wherein, when a number of submitting the packet becomes a predetermined value, submitting the packet is stopped.

Abstract: A method for managing connections by a user equipment (UE) in a wireless communication system is disclosed. The method comprises steps of receiving a handover command from a first network; performing a random access procedure to a second network while maintaining a connection of the first network; based on a radio link problem associated with the first network being detected, releasing the connection of the first network; and reporting information related to the radio link problem associated with the first network to the second network after performing the random access procedure is successfully completed.

Abstract: A method and apparatus for path selection scheme for a master cell group (MCG) failure reporting is provided. A wireless device configured to operate in a wireless communication system determines a path for master cell group (MCG) failure information to inform a failure on a primary cell (PCell) of a MCG from among the at least one secondary ell (SCell) of the MCG and a secondary cell group (SCG), and transmits the MCG failure information via the determined path.

Abstract: The present invention relates to a method for processing data units by a Packet Data Convergence Protocol (PDCP) entity of a user equipment (UE) in a wireless communication system. In particular, the method includes the steps of: receiving a first data unit having a specific count value from a lower layer; and discarding the first data unit, when there is a second data unit having the specific count value which was received before the first data unit and for which an integrity verification was successful.

Abstract: Provided are a method for performing, by a user equipment (UE), transmission via only a primary path in a wireless communication system, and an apparatus supporting the same. The method may include: configuring a split bearer, which has multiple L2 entities for both a master cell group (MCG) and a secondary cell group (SCG); when the UE transits from a first state to a second state, reconfiguring the primary path of the split bearer autonomously; and performing the transmission via only the primary path of the split bearer, wherein the primary path is related to an L2 entity for the MCG.

Abstract: The present invention relates to a method for transmitting signals by a transmission end in a wireless communication system. In particular, the method includes the steps of: configuring one Packet Data Convergence Protocol (PDCP) entity, at least one first RLC entity related to the one PDCP entity and at least one second RLC entity related to the one PDCP entity; determining whether a service data unit (SDU) to be transmitted is a special SDU or not; if the SDU is the special SDU, transmitting the SDU to the at least one first RLC entity; and if the SDU is not the special SDU, transmitting the SDU to the at least one second RLC entity.

Abstract: In the present invention, the method, communication device or processing device selects logical channels related to an uplink (UL) grant and allocates resources of the UL grant to the selected logical channels. The present invention selects the logical channels related to the UL grant among logical channels not related to a suspended radio link control (RLC) entity among RLC entities configured in the communication or processing device.

Abstract: The present invention relates to a method for performing retransmissions by a transmission end in a wireless communication system. In particular, the method includes the steps of: re-transmitting a data unit to a reception end; and increasing a retransmission counter associated with the data unit, when the retransmission counter associated with the data unit reaches to a max value, reporting a max retransmission indication to an upper layer and setting the retransmission counter associated with the data unit to zero.