The present disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. According to an aspect of the embodiments of the present disclosure, a method for supporting handover is provided, comprising: receiving a message from a central unit control plane entity of a target base station; receiving a data packet from a source base station; and discarding a packet data convergence protocol (PDCP) service data unit (SDU) including the PDCP sequence number (SN) in the received data packet according to the indication of the message. The problem of coordinated work between the source base station and the target base station during the handover process may be solved. Especially when the source base station and/or the target base station support the separation of the control plane and the user plane, ensure that the central unit control plane entity of the source base station, the central unit user plane entity of the source base station, the central unit control plane entity of the target base station and/or the central unit user plane entity of the target base station may fully coordinately work.

The present disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The present disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. According to an aspect of the embodiments of the present disclosure, a method for supporting handover is provided, comprising: receiving a message from a central unit control plane entity of a target base station; receiving a data packet from a source base station; and discarding a packet data convergence protocol (PDCP) service data unit (SDU) including the PDCP sequence number (SN) in the received data packet according to the indication of the message. The problem of coordinated work between the source base station and the target base station during the handover process may be solved. Especially when the source base station and/or the target base station support the separation of the control plane and the user plane, ensure that the central unit control plane entity of the source base station, the central unit user plane entity of the source base station, the central unit control plane entity of the target base station and/or the central unit user plane entity of the target base station may fully coordinately work.

Apparatuses, methods, and systems are disclosed for determining data available for transmission. One method includes associating a packet data convergence protocol entity with a first radio link control entity and a second radio link control entity belonging to two different cell groups. The method includes determining an amount of data available for transmission, the amount of data available for transmission including packet data convergence protocol data and radio link control data pending for initial transmission in the first radio link control entity and the second radio link control entity. The method includes comparing the amount of data available for transmission with a threshold. The method includes submitting the packet data convergence protocol data to a first radio link control entity in response to the amount of data available for transmission being below the threshold.

Apparatuses, methods, and systems are disclosed for determining data available for transmission. One method includes associating a packet data convergence protocol entity with a first radio link control entity and a second radio link control entity belonging to two different cell groups. The method includes determining an amount of data available for transmission, the amount of data available for transmission including packet data convergence protocol data and radio link control data pending for initial transmission in the first radio link control entity and the second radio link control entity. The method includes comparing the amount of data available for transmission with a threshold. The method includes submitting the packet data convergence protocol data to a first radio link control entity in response to the amount of data available for transmission being below the threshold.

A method is provided, including: configuring a conditional candidate primary secondary cell group cell PSCell addition or change for a terminal device; and performing, by a master network device, early data transmission oriented to a network device to which a candidate PSCell belongs, and for example, before the terminal device accesses the candidate PSCell, sending a data packet to the network device to which the candidate PSCell belongs, where a form of the data packet is a packet data convergence protocol protocol data unit, and the data packet includes a data packet on an MN terminated secondary cell group bearer and/or a data packet on an MN terminated split bearer. In this way, after the terminal device accesses a candidate network device, the candidate network device may send forwarded data to the terminal device, to reduce a data transmission delay.

Methods and systems are disclosed for a UE of a wireless communication network to recover from MCG radio link failures in a MR-DC system when the SCG is deactivated or otherwise not enabled. When a MCG link failure is detected and the SCG is deactivated, the UE may activate the SCG for the UE to use the SCG link to transmit and receive signaling messages or data as part of the MCG failure recovery procedure. When the MCG link failure is detected and the UE is configured to add the SCG upon the satisfaction of certain condition, but the condition has not occurred, the UE may check to determine whether one condition is MCG failure and whether the radio link quality of the SCG exceeds a threshold. If the radio link quality of the SCG exceeds the threshold, the UE may apply the SCG configuration to add the SCG.

Embodiments of the present disclosure provide a system information reception method applied to user equipment. The method includes: determining a cell corresponding to system information to be obtained; transmitting a request message to a base station for requesting the system information of the cell, where the request message includes indication information of the cell; and receiving the system information of the cell transmitted by the base station.

Data forwarding may be useful in many communication systems. Thus, for example, data forwarding support may be useful in dual connectivity in, for example, the third generation partnership project (3GPP) and more particularly to dual connectivity with enabled downlink (DL) data back forwarding. A method can include receiving, by a first network node, an indication indicating that for at least one split bearer, data received prior to the indication is to be forwarded to a second network node. The indication can also indicate that the at least one split bearer should be kept or maintained at the first network node. The method can also include, in response to the received indication, forwarding the data for the at least one split bearer received prior to the indication to the second network node.

A method of operating a Master gNodeB (MgNB) in a radio access network RAN is disclosed. An indication of a user plane security policy is received from a core network node, wherein the user plane security policy requires user plane integrity protection for a protocol data unit PDU session. Responsive to the user plane security policy requiring user plane integrity protection for the PDU session and responsive to determining that a secondary base station supporting the user plane security policy requiring user plane integrity protection is unavailable, a data radio bearer DRB of the PDU session is established directly between the MgNB and a user equipment UE. Related MgNBs are also discussed.

Embodiments herein disclose a method performed by a wireless device (10) for handling connections in a wireless communication network, wherein the wireless device (10) is configured with a split signaling radio bearer to a first radio network node (12), being a master radio network node, and a second radio network node (13), being a secondary radio network node. The wireless device detects a radio link problem to the first radio network node (12); and transmits a failure report to the first radio network node (12) over the split signaling radio bearer via the second radio network node (13). The failure report indicates the radio link problem to the first radio network node (12).