One aspect provides a method performed by a radio access network node in a telecommunications network. The method comprises: responsive to detection of a trigger event associated with a wireless device having a connection to the telecommunications network via the radio access network node or seeking to establish a connection to the telecommunications network via the radio access network node, transmitting, directly to a user plane core network node, a message initiating establishment of a user-plane tunnel for the connection between the radio access network node and the user plane core network node. The message comprises one or more of: an indication of an identifier of the wireless device; and an indication of an identifier of a session for the wireless device, and further comprises an indication of a downlink tunnel endpoint identifier of the radio access network node.

One aspect provides a method performed by a radio access network node in a telecommunications network. The method comprises: responsive to detection of a trigger event associated with a wireless device having a connection to the telecommunications network via the radio access network node or seeking to establish a connection to the telecommunications network via the radio access network node, transmitting, directly to a user plane core network node, a message initiating establishment of a user-plane tunnel for the connection between the radio access network node and the user plane core network node. The message comprises one or more of: an indication of an identifier of the wireless device; and an indication of an identifier of a session for the wireless device, and further comprises an indication of a downlink tunnel endpoint identifier of the radio access network node.

Data retransmission method is disclosed. The method includes: obtaining a mapping relationship between GTP-U sequence numbers of N data packets sent by a source node and source PDCP sequence numbers assigned to the N data packets by the source node; and performing data retransmission based on the mapping relationship.

Systems, methods, apparatuses, and computer program products for mobility failure evidence-related operations. A UE may measure, record, and report a channel access waiting (CAW) time period that elapsed from having a handover-related message in a transmission buffer until a channel for transmission of the handover-related message was obtained or until an acknowledgement or negative acknowledgement from a receiver of the handover-related message was received. The CAW time period information may be provided to a network node, and the network node may control mobility robustness optimization based on the received information.

Certain embodiments generally relate to mobile communications networks, such as, but not limited to, the Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN), Long Term Evolution (LTE) Evolved UTRAN (E-UTRAN), LTE-A, and/or future mobile network technologies, such as, for example 5th Generation (5G). A method may include detecting, at a mobile network entity, that context information pertaining to a mobile terminal has changed. The method may also include publishing updated context information through implementation of a publish/subscribe mechanism.

A more efficient network can be achieved by leveraging an adaptive dejitter buffer. The dejitter buffer can be dynamically adjusted based off a network data analysis. A communication handover can be adjusted or shifted based on voice inactivity data related to a forecasted punctuation. The dejitter buffer memory/depth of a mobile device can also be adjusted in accordance with receiving a delay interruption length associated with another mobile device. Thereafter, the dejitter buffer memory can be filled with voice packet data to decrease a packet delay variation at the mobile device.

A system is proposed to provide handover in a mobile telecommunications environment, particularly applicable to 3GPP networks, which does not increase signalling overhead but minimises user data loss during handover. In the modified system, PDCP SDUs with Sequence numbers are buffered and retransmitted as necessary. At the time of handover, SDUs not received by the user device are forwarded to the target base station for forward transmission to the UE. The handover procedure is designed to minimise packet loss whilst keeping to a minimum the duplication of packet transmission over the air interface.

A system is proposed to provide handover in a mobile telecommunications environment, particularly applicable to 3GPP networks, which does not increase signalling overhead but minimises user data loss during handover. In the modified system, PDCP SDUs with Sequence numbers are buffered and retransmitted as necessary. At the time of handover, SDUs not received by the user device are forwarded to the target base station for forward transmission to the UE. The handover procedure is designed to minimise packet loss whilst keeping to a minimum the duplication of packet transmission over the air interface.

An apparatus of a base station (BS) of a radio access network (RAN) comprises memory and processing circuitry. The processing circuitry includes a central unit (CU) portion and a distributed unit (DUI) portion that implement a BS multi-layer protocol stack divided between the CU portion and the DU portion. The processing circuitry initiates a handover to change a serving cell of user equipment (UE). The handover includes a change in a portion of logical layers of the BS multi-layer protocol stack, and the processing circuitry encodes an information element for transmission to the UE indicating logical layers of a UE multi-layer protocol stack implemented in the UE to be reset by the UE in association with the handover.

An apparatus of a base station (BS) of a radio access network (RAN) comprises memory and processing circuitry. The processing circuitry includes a central unit (CU) portion and a distributed unit (DUI) portion that implement a BS multi-layer protocol stack divided between the CU portion and the DU portion. The processing circuitry initiates a handover to change a serving cell of user equipment (UE). The handover includes a change in a portion of logical layers of the BS multi-layer protocol stack, and the processing circuitry encodes an information element for transmission to the UE indicating logical layers of a UE multi-layer protocol stack implemented in the UE to be reset by the UE in association with the handover.