Handling handover requiring data radio bearer release and addition

Abstract

A method is disclosed, comprising: determining whether a target cell configuration of a target cell for a handover of a user equipment corresponds to a source cell configuration of a source cell for the handover of the user equipment; based on determining that the target cell configuration does not correspond to the source cell configuration, determining to release and add at least one data radio bearer for the handover of the user equipment; and transmitting, to a distributed unit of a radio access network node controlling the target cell, an indication to indicate the release and the addition of the at least one data radio bearer for the handover of the user equipment.

Description

Technical Field

[0001] The following example embodiments relate to wireless communication. Background Technology

[0002] In wireless communication, handover refers to the process of transferring a user equipment's connection from one cell to another while preserving an ongoing voice call or data session. Summary of the Invention

[0003] The scope of protection sought with respect to the various exemplary embodiments is set forth in the independent claims. Exemplary embodiments and features (if any) described in this specification that do not fall within the scope of the independent claims are to be interpreted as examples useful for understanding the various embodiments.

[0004] According to one aspect, an apparatus is provided, comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to at least: determine whether a target cell configuration of a target cell for handover to a user equipment corresponds to a source cell configuration of a source cell for handover to the user equipment; based on the determination that the target cell configuration does not correspond to the source cell configuration, determine to release and add at least one data radio bearer for handover to the user equipment; and perform at least one of the following: transmitting an instruction to a distributed unit of a radio access network node controlling the target cell, the instruction indicating the release and addition of the at least one data radio bearer for handover to the user equipment; or transmitting an instruction to a radio access network node controlling the source cell, the instruction indicating that the user equipment maintains a pre-configured mapping between at least one logical channel identifier of at least one radio link control bearer and at least one identifier of the at least one data radio bearer during handover when releasing and adding the at least one data radio bearer.

[0005] According to another aspect, an apparatus is provided, comprising: components for determining whether a target cell configuration of a target cell for handover to a user equipment corresponds to a source cell configuration of a source cell for handover to the user equipment; components for determining, based on the determination that the target cell configuration does not correspond to the source cell configuration, to release and add at least one data radio bearer for handover to the user equipment; and components for performing at least one of the following: transmitting an instruction to a distributed unit of a radio access network node controlling the target cell, the instruction indicating the release and addition of the at least one data radio bearer for handover to the user equipment; or transmitting an instruction to a radio access network node controlling the source cell, the instruction indicating that the user equipment maintains a pre-configured mapping between at least one logical channel identifier of at least one radio link control bearer and at least one identifier of the at least one data radio bearer during handover when releasing and adding the at least one data radio bearer.

[0006] According to another aspect, a method is provided, comprising: determining whether the target cell configuration of the target cell for handover to a user equipment corresponds to the source cell configuration of the source cell for handover to the user equipment; determining, based on the determination that the target cell configuration does not correspond to the source cell configuration, to release and add at least one data radio bearer for handover to the user equipment; and performing at least one of the following: transmitting an instruction to a distributed element of a radio access network node controlling the target cell, the instruction indicating the release and addition of the at least one data radio bearer for handover to the user equipment; or transmitting an instruction to a radio access network node controlling the source cell, the instruction indicating that the user equipment maintains a pre-configured mapping between at least one logical channel identifier of at least one radio link control bearer and at least one identifier of the at least one data radio bearer during handover when releasing and adding the at least one data radio bearer.

[0007] According to another aspect, a computer program is provided, including instructions that, when executed by an apparatus, cause the apparatus to perform at least the following operations: determining whether the target cell configuration of the target cell for handover to a user equipment corresponds to the source cell configuration of the source cell for handover to the user equipment; determining, based on the determination that the target cell configuration does not correspond to the source cell configuration, to release and add at least one data radio bearer for handover to the user equipment; and performing at least one of the following: transmitting an instruction to a distributed unit of a radio access network node controlling the target cell, the instruction indicating the release and addition of the at least one data radio bearer for handover to the user equipment; or transmitting an instruction to a radio access network node controlling the source cell, the instruction indicating that the user equipment maintains a pre-configured mapping between at least one logical channel identifier of at least one radio link control bearer and at least one identifier of the at least one data radio bearer during handover when releasing and adding the at least one data radio bearer.

[0008] According to another aspect, a computer-readable medium is provided, including program instructions that, when executed by an apparatus, cause the apparatus to perform at least the following operations: determining whether a target cell configuration of a target cell for handover to a user equipment corresponds to a source cell configuration of a source cell for handover to the user equipment; determining, based on the determination that the target cell configuration does not correspond to the source cell configuration, to release and add at least one data radio bearer for handover to the user equipment; and performing at least one of the following: transmitting an instruction to a distributed unit of a radio access network node controlling the target cell, the instruction indicating the release and addition of the at least one data radio bearer for handover to the user equipment; or transmitting an instruction to a radio access network node controlling the source cell, the instruction indicating that the user equipment maintains a pre-configured mapping between at least one logical channel identifier of at least one radio link control bearer and at least one identifier of the at least one data radio bearer during handover when releasing and adding the at least one data radio bearer.

[0009] According to another aspect, a non-transitory computer-readable medium is provided, including program instructions that, when executed by an apparatus, cause the apparatus to perform at least the following operations: determining whether the target cell configuration of the target cell for handover to a user equipment corresponds to the source cell configuration of the source cell for handover to the user equipment; determining, based on the determination that the target cell configuration does not correspond to the source cell configuration, to release and add at least one data radio bearer for handover to the user equipment; and performing at least one of the following: transmitting an instruction to a distributed unit of a radio access network node controlling the target cell, the instruction being used to instruct the release and addition of the at least one data radio bearer for handover to the user equipment; or transmitting an instruction to a radio access network node controlling the source cell, the instruction being used to instruct the user equipment to maintain a pre-configured mapping between at least one logical channel identifier of at least one radio link control bearer and at least one identifier of the at least one data radio bearer during handover when releasing and adding the at least one data radio bearer.

[0010] According to another aspect, an apparatus is provided, comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to at least: receive from a central unit of a radio access network node an instruction indicating the release and addition of at least one data radio bearer for a handover of a user equipment; determine at least one radio link control bearer associated with the at least one data radio bearer; prepare a cell group configuration based on the instruction for the release and addition of the at least one radio link control bearer associated with the at least one data radio bearer for a handover of a user equipment; and transmit the cell group configuration to the central unit, wherein the cell group configuration indicates the at least one radio link control bearer to be released and added.

[0011] According to another aspect, an apparatus is provided, comprising: components for receiving from a central unit of a radio access network node an instruction to release and add at least one data radio bearer for a user equipment during handover; components for determining at least one radio link control bearer associated with the at least one data radio bearer; and components for releasing and adding at least one radio link control bearer when the user equipment connects to a target cell controlled by the radio access network node during handover.

[0012] According to another aspect, a method is provided, comprising: receiving from a central unit of a radio access network node an instruction to release and add at least one data radio bearer for handover of a user equipment; determining at least one radio link control bearer associated with at least one data radio bearer; and releasing and adding at least one radio link control bearer when the user equipment connects to a target cell controlled by the radio access network node during handover.

[0013] According to another aspect, a computer program is provided, including instructions that, when executed by a device, cause the device to perform at least the following operations: receiving from a central unit of a radio access network node an instruction to release and add at least one data radio bearer for handover of a user equipment; determining at least one radio link control bearer associated with the at least one data radio bearer; and releasing and adding the at least one radio link control bearer when the user equipment connects to a target cell controlled by the radio access network node during handover.

[0014] According to another aspect, a computer-readable medium including program instructions is provided, which, when executed by an apparatus, cause the apparatus to perform at least the following operations: receiving from a central unit of a radio access network node an instruction to release and add at least one data radio bearer for handover of a user equipment; determining at least one radio link control bearer associated with at least one data radio bearer; and releasing and adding at least one radio link control bearer when the user equipment connects to a target cell controlled by the radio access network node during handover.

[0015] According to another aspect, a non-transitory computer-readable medium including program instructions is provided, which, when executed by an apparatus, cause the apparatus to perform at least the following operations: receiving from a central unit of a radio access network node an instruction to release and add at least one data radio bearer for handover of a user equipment; determining at least one radio link control bearer associated with at least one data radio bearer; and releasing and adding at least one radio link control bearer when the user equipment connects to a target cell controlled by the radio access network node during handover.

[0016] According to one aspect, an apparatus is provided, comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to at least: receive an instruction from a radio access network node, the instruction indicating to maintain a pre-configured mapping between at least one logical channel identifier of at least one radio link control bearer and at least one identifier of at least one data radio bearer for releasing and adding the at least one data radio bearer during handover; maintain the pre-configured mapping between the at least one logical channel identifier and the at least one identifier of the at least one data radio bearer based on the instruction during the release and addition of the at least one data radio bearer during handover; and apply the maintained mapping to route data packets after handover.

[0017] According to another aspect, an apparatus is provided, comprising: components for receiving an instruction from a radio access network node, the instruction indicating to maintain a pre-configured mapping between at least one logical channel identifier of at least one radio link control bearer and at least one identifier of at least one data radio bearer for releasing and adding the at least one data radio bearer during handover; components for maintaining the pre-configured mapping between the at least one logical channel identifier and the at least one identifier of the at least one data radio bearer based on the instruction during the release and addition of the at least one data radio bearer during handover; and components for applying the maintained mapping to route data packets after handover.

[0018] According to another aspect, a method is provided, comprising: receiving an indication from a radio access network node, the indication being used to instruct maintaining a pre-configured mapping between at least one logical channel identifier of at least one radio link control bearer and at least one identifier of at least one data radio bearer for the release and addition of at least one data radio bearer during handover; maintaining the pre-configured mapping between the at least one logical channel identifier and the at least one identifier of the at least one data radio bearer based on the indication during the release and addition of the at least one data radio bearer during handover; and applying the maintained mapping to route data packets after handover.

[0019] According to another aspect, a computer program is provided, including instructions that, when executed by a device, cause the device to perform at least the following operations: receiving an instruction from a radio access network node, the instruction indicating to maintain a pre-configured mapping between at least one logical channel identifier of at least one radio link control bearer and at least one identifier of at least one data radio bearer for the release and addition of the at least one data radio bearer during handover; maintaining the pre-configured mapping between the at least one logical channel identifier and the at least one identifier of the at least one data radio bearer based on the instruction during the release and addition of the at least one data radio bearer during handover; and applying the maintained mapping to route data packets after handover.

[0020] According to another aspect, a computer-readable medium is provided, including program instructions that, when executed by a device, cause the device to perform at least the following operations: receiving an instruction from a radio access network node, the instruction indicating to maintain a pre-configured mapping between at least one logical channel identifier of at least one radio link control bearer and at least one identifier of at least one data radio bearer for the release and addition of the at least one data radio bearer during handover; maintaining the pre-configured mapping between the at least one logical channel identifier and the at least one identifier of the at least one data radio bearer based on the instruction during the release and addition of the at least one data radio bearer during handover; and applying the maintained mapping to route data packets after handover.

[0021] According to another aspect, a non-transitory computer-readable medium is provided, including program instructions that, when executed by a device, cause the device to perform at least the following operations: receiving an instruction from a radio access network node, the instruction indicating to maintain a pre-configured mapping between at least one logical channel identifier of at least one radio link control bearer and at least one identifier of at least one data radio bearer for the release and addition of the at least one data radio bearer during handover; maintaining the pre-configured mapping between the at least one logical channel identifier and the at least one identifier of the at least one data radio bearer based on the instruction during the release and addition of the at least one data radio bearer during handover; and applying the maintained mapping to route data packets after handover. Attached Figure Description

[0022] In the following description, various exemplary embodiments will be described in more detail with reference to the accompanying drawings, wherein Figure 1A An example of a wireless communication network is shown; Figure 1B An example of the system is shown; Figure 2 The signal flow graph is shown; Figure 3 The signal flow graph is shown; Figure 4 A flowchart is shown; Figure 5 A flowchart is shown; Figure 6 A flowchart is shown; Figure 7 A flowchart is shown; Figure 8 A flowchart is shown; Figure 9 A flowchart is shown; Figure 10 An example of the device is shown; Figure 11An example of the device is shown; and Figure 12 An example of the device is shown. Detailed Implementation

[0023] The following embodiments are exemplary. Although the specification may refer to "a," "an," or "some" embodiments in several places in the text, this does not necessarily mean that the same embodiment(s) is mentioned every time, or that a particular feature applies only to a single embodiment. Individual features of different embodiments may also be combined to provide other embodiments. Furthermore, the words "comprising" and "including" should be understood not to limit the described embodiments to consisting only of those features already mentioned, and such embodiments may also include features not specifically mentioned. Reference numerals in the specification and / or claims are used to illustrate embodiments with reference to the accompanying drawings, and not to limit the embodiments to these examples.

[0024] Some of the example embodiments described herein can be implemented in wireless communication networks including radio access networks based on one or more of the following radio access technologies (RATs): Global System for Mobile Communications (GSM) or any other second-generation radio access technology, Universal Mobile Telecommunications System (UMTS, 3G) based on Basic Wideband Code Division Multiple Access (W-CDMA), High-Speed ​​Packet Access (HSPA), Long Term Evolution (LTE), LTE-Advanced, Fourth Generation (4G), Fifth Generation (5G), 5G New Radio (NR), 5G Advanced (i.e., 3GPP NR Rel-18 and above), or Sixth Generation (6G). Some examples of radio access networks include Universal Mobile Telecommunications System (UMTS) Radio Access Network (UTRAN), Evolved Universal Terrestrial Radio Access Network (E-UTRA), or Next Generation Radio Access Network (NG-RAN). The wireless communication network may also include a core network, and some example embodiments can also be applied to the network functions of the core network.

[0025] It should be noted that the embodiments are not limited to the wireless communication networks given as examples, but those skilled in the art can apply the solutions to other wireless communication networks or systems with the necessary properties. For example, some example embodiments can also be applied to communication systems based on the IEEE 802.11 standard or the IEEE 802.15 standard. IEEE is an abbreviation for the Institute of Electrical and Electronics Engineers.

[0026] Figure 1A An example of a simplified wireless communication network is depicted, showing some physical and logical entities. Figure 1A The connection shown can be a physical connection or a logical connection. It will be apparent to those skilled in the art that the wireless communication network may also include, in addition to… Figure 1AOther physical and logical entities besides those shown.

[0027] However, the exemplary embodiments described herein are not limited to the wireless communication networks given as examples, but those skilled in the art can apply the exemplary embodiments described herein to other wireless communication networks that provide the necessary properties.

[0028] Figure 1A The example wireless communication network shown includes a radio access network (RAN) and a core network 110.

[0029] Figure 1A User equipment (UE) 100, 102 is shown that is configured to wirelessly connect to access node 104 of radio access network on one or more communication channels in radio cell.

[0030] Access node 104 may include a computing device configured to control the radio resources of access node 104 and wirelessly connected to one or more UEs 100, 102. Access node 104 may also be referred to as a base station, base transceiver station (BTS), access point, cell site, network node, radio access network node, or RAN node. Access node 104 may be, for example, an evolved NodeB (eNB or e NodeB) providing a radio cell, or a next-generation evolved NodeB (ng-eNB), or a next-generation NodeB (gNB or g NodeB). Access node 104 may include or be coupled to a transceiver. A connection may be provided from the transceiver of access node 104 to an antenna element that establishes a bidirectional radio link to one or more UEs 100, 102. The antenna element may include an antenna or antenna element, or multiple antennas or antenna elements.

[0031] The radio connection (e.g., a radio link) from UE 100, 102 to access node 104 may be referred to as an uplink (UL) or reverse link, and the radio connection (e.g., a radio link) from access node 104 to UE 100, 102 may be referred to as a downlink (DL) or forward link. UE 100 may also communicate directly with another UE 102 via a radio connection commonly referred to as a side link (SL), and vice versa. It should be understood that access node 104 or its functionality may be implemented using any node, host, server, access point, or other entity suitable for providing such functionality.

[0032] A radio access network may include more than one access node 104, in which case the access nodes may also be configured to communicate with each other via wired or wireless links. These links between access nodes may be used to send and receive control plane signaling, and also to route data from one access node to another.

[0033] Access node 104 may also connect to core network (CN) 110. Core network 110 may include an evolved packet core (EPC) network and / or a fifth-generation core network (5GC). EPC may include network entities such as a serving gateway (S-GW for routing and forwarding data packets), a packet data network gateway (P-GW) for providing connectivity to external packet data networks for the UE, and / or a mobility management entity (MME). 5GC may include one or more network functions such as at least one of the following: user plane function (UPF), access and mobility management function (AMF), location management function (LMF), and / or session management function (SMF).

[0034] The core network 110 may also be able to communicate with or utilize services provided by one or more external networks 113 (such as the public switched telephone network or the Internet). For example, in a 5G wireless communication network, the UPF of the core network 110 may be configured to communicate with an external data network via an N6 interface. In an LTE wireless communication network, the P-GW of the core network 110 may be configured to communicate with an external data network.

[0035] It should also be understood that, compared to LTE or 5G, the functional distribution between core network operations and access node operations may differ in future wireless communication networks, or may not even exist.

[0036] The illustrated UEs 100 and 102 are a type of apparatus to which resources on the air interface can be allocated and assigned. UEs 100 and 102 may also be referred to as wireless communication devices, subscriber units, mobile stations, remote terminals, access terminals, user terminals, terminal equipment, or user equipment, to name just a few. UEs 100 and 102 may be computing devices operating with or without a subscriber identification module (SIM), including but not limited to the following types of computing devices: mobile phones, smartphones, personal digital assistants (PDAs), handheld devices, computing devices including wireless modems (e.g., alarm or measuring devices), laptop computers, desktop computers, tablet devices, game consoles, notebooks, multimedia devices, redcap devices, wearable devices with radio components (e.g., watches, headphones, or glasses), sensors including wireless modems, or computing devices including wireless modems integrated into vehicles.

[0037] It should be understood that UE 100,102 can also be virtually exclusive uplink-only devices, examples of which could be cameras or camcorders that load images or video clips onto the network. UE 100,102 can also be devices capable of operating in Internet of Things (IoT) networks, which are scenarios where the ability to transmit data over the network to objects can be provided without human-to-human or human-to-computer interaction is required.

[0038] Wireless communication networks can also support the use of cloud services. For example, at least a portion of core network operations can be performed as a cloud service (this is in...). Figure 1A (Depicted by "cloud" 114). UEs 100 and 102 can also utilize cloud 114. In some applications, computations for a given UE can be performed in cloud 114 or another UE.

[0039] Wireless communication networks can also include a central control entity, such as a Network Management System (NMS). An NMS is a centralized suite of software and hardware used to monitor, control, and manage network infrastructure. The NMS is responsible for a wide range of tasks, such as fault management, configuration management, security management, performance management, and accounting management. The NMS enables network operators to effectively manage and optimize network resources, ensuring that the network delivers high performance, reliability, and security.

[0040] 5G enables the use of multiple-input multiple-output (MIMO) antennas in access nodes 104 and / or UEs 100, 102, and far more base stations or access nodes than LTE networks (the so-called small cell concept), including macro sites that cooperate with smaller stations and employ various radio technologies depending on service requirements, use cases, and / or available spectrum. 5G wireless communication networks can support a wide range of use cases and related applications, including video streaming, augmented reality, different data sharing methods, and various forms of machine-type applications such as (massive) machine-type communication (mMTC), including vehicle safety, various sensors, and real-time control.

[0041] In 5G wireless communication networks, access nodes and / or UEs can have multiple radio interfaces, such as sub-6 GHz, centimeter wave (cmWave), and millimeter wave (mmWave), and can also be integrated with traditional radio access technologies (such as LTE). Integration with LTE can be implemented, for example, in a system where macro coverage can be provided by LTE, and 5G radio interface access can originate from small cells by aggregation to LTE. In other words, 5G wireless communication networks can support inter-RAT interoperability (such as interoperability between LTE and 5G) and inter-RI interoperability (interoperability between radio interfaces, such as between sub-6 GHz, cmWave, and mmWave).

[0042] 5G wireless communication networks can also apply network slicing, where multiple independent and dedicated virtual sub-networks (network instances) can be created within the same physical infrastructure to run services with different requirements for latency, reliability, throughput, and mobility.

[0043] In one embodiment, access node 104 may include: a radio unit (RU) comprising a radio transceiver (TRX), i.e., a transmitter (Tx) and a receiver (Rx); one or more distributed units (DUs) 105, which may be used for so-called Layer 1 (L1) processing and real-time Layer 2 (L2) processing; and a central unit (CU) 108 (also referred to as a centralized unit), which may be used for non-real-time Layer 2 and Layer 3 (L3) processing. CU 108 may be connected to one or more DUs 105, for example, via an F1 interface. Such an embodiment of access node 104 allows for the centralization of CUs relative to cell sites and DUs, while DUs can be more distributed and may even remain at the cell site. CUs and DUs together may also be referred to as baseband or baseband unit (BBU). CUs and DUs may also be included in a radio access point (RAP).

[0044] CU 108 may be a logical node hosting the Managed Radio Resource Control (RRC), Serving Data Adaptation Protocol (SDAP), and / or Packet Data Convergence Protocol (PDCP) for the NR protocol stack of access node 104. CU 108 may include a control plane (CU-CP), which may be a logical node hosting the control plane portions of the RRC and PDCP protocols for the NR protocol stack of access node 104. CU 108 may also include a user plane (CU-UP), which may be a logical node hosting the user plane portions of the PDCP and SDAP protocols for the CU of access node 104.

[0045] DU 105 may be a logical node hosting the Radio Link Control (RLC), Media Access Control (MAC), and / or Physical (PHY) layers of the NR protocol stack used by Access Node 104. The operation of DU 105 may be controlled at least partially by CU 108. It should also be understood that the functional distribution between DU 105 and CU 108 may vary depending on the specific implementation.

[0046] Cloud computing systems can also be used to provide CU 108 and / or DU 105. CUs provided by cloud computing systems can be referred to as virtualized CUs (vCUs). In addition to vCUs, virtualized DUs (vDUs) provided by cloud computing systems can also exist. Furthermore, combinations can exist where DUs can be implemented on so-called bare-metal solutions, such as application-specific integrated circuits (ASICs) or customer-specific standard product (CSSP) system-on-chips (SoCs).

[0047] Edge cloud can be brought into radio access networks by leveraging Network Functions Virtualization (NFV) and Software-Defined Networking (SDN). Using edge cloud can mean at least partially performing access node operations on a computing system operatively coupled to a Remote Radio Head (RRH) or Radio Unit (RU) at access node 104. Access node operations can also be performed on a distributed computing system or cloud computing system located at access node 104. The application of a cloud RAN architecture enables the execution of real-time RAN functions at the radio access network (e.g., in DU 105) and non-real-time functions in a centralized manner (e.g., in CU 108).

[0048] 5G (or New Radio, NR) wireless communication networks can support multiple tiers, where multi-access edge computing (MEC) servers can be placed between the core network 110 and access nodes 104. It should be understood that MEC can also be applied to LTE wireless communication networks.

[0049] 5G wireless communication networks (“5G networks”) may also include non-terrestrial communication networks, such as satellite communication networks, to enhance or supplement the coverage of 5G radio access networks. For example, satellite communications can support data transmission between the 5G radio access network and the core network 110, thereby achieving broader network coverage. Possible use cases may include providing service continuity for machine-to-machine (M2M) or Internet of Things (IoT) devices or for passengers on transportation vehicles, or ensuring the service availability of critical communications and future rail, sea, or air communications. Satellite communications may utilize geostationary Earth orbit (GEO) satellite systems, but may also utilize low Earth orbit (LEO) satellite systems, particularly mega-constellations (i.e., systems in which hundreds of (nanometer) satellites are deployed). A given satellite 106 in a mega-constellation can cover network entities of several supporting satellites that create terrestrial cells. Terrestrial cells can be created by terrestrial relay access nodes or by access nodes located on the ground or in satellites.

[0050] It is obvious to those skilled in the art that Figure 1A The access node 104 depicted is merely an example of a portion of a radio access network, and in practice, a radio access network may include multiple access nodes 104, UEs 100 and 102 may access multiple radio cells, and the radio access network may also include other devices, such as physical layer relay access nodes or other entities. At least one of the access nodes may be a home eNodeB or a home gNodeB. A home gNodeB or home eNodeB is a type of access node that can be used to provide indoor coverage in a home, office, or other indoor environment.

[0051] In addition, multiple different types of radio cells and multiple radio cells can be provided within the geographical area of ​​the radio access network. Radio cells can be macrocells (or umbrella cells), which can be large cells with diameters of up to tens of kilometers, or smaller cells such as microcells, femtocells, or picocells. Figure 1A The (multiple) access nodes 104 can provide any type of these cells. A cellular radio network can be implemented as a multi-layered access network comprising several radio cells. In a multi-layered access network, one access node can provide one or more radio cells, thus multiple access nodes may be required to provide such a multi-layered access network.

[0052] To meet the need for improved performance in radio access networks, the concept of "plug-and-play" access nodes can be introduced. In addition to home eNodeBs or home gNodeBs, radio access networks capable of using "plug-and-play" access nodes can also include home node B gateways (HNB-GW). Figure 1A (Not shown in the image). An HNB-GW, which can be installed within an operator's radio access network, can aggregate traffic from a large number of home eNodeBs or home gNodeBs back to the operator's core network 110.

[0053] Figure 1B Examples of systems to which some example embodiments can be applied are shown. Figure 1B It can be understood as depicting Figure 1A It is part of a wireless communication network, but has higher accuracy compared to mobile scenarios.

[0054] refer to Figure 1B During the handover, the connection of UE 100 is transferred from the current serving cell (source cell) 121 controlled by the source RAN node 104B to the target cell 122 provided by the target RAN node 104, while the ongoing voice call or data session is preserved.

[0055] When certain predefined conditions are met, such as when the signal quality of the current serving cell 121 drops below a specified threshold, or when the signal quality of the neighboring cell 122 becomes better than the signal quality of the current serving cell 121 by a predefined offset, the handover process can be initiated by the network (e.g., source RAN node 104B). The decision to perform the handover can be based on various factors, including radio measurements such as Reference Received Power (RSRP) and / or Reference Received Quality (RSRQ), network load, UE mobility, and network configuration parameters.

[0056] During the handover process, the network (e.g., source RAN node 104B) can transmit a handover command to UE 100, which may include information about the target cell 122 and any required configuration parameters. UE 100 can then establish a connection with the target RAN node 104B providing the target cell 122, synchronize their timing and frequency, and exchange control information to confirm successful handover. Once the handover is complete, UE 100 releases its connection to the previous serving cell 121, and communication continues through the new serving cell 122.

[0057] The handover can be an intra-RAT handover or an inter-RAT handover.

[0058] Intra-RAT handover means that source cell 121 and target cell 122 are based on the same radio access technology. For example, in intra-NR handover, both source RAN node 104B and target RAN node 104 can be gNBs (i.e., NR base stations).

[0059] Inter-RAT handover means that the source cell 121 and the target cell 122 are based on different radio access technologies. For example, in an inter-RAT handover, the source RAN node 104B can be an eNB or an ng-eNB (i.e., a 4G base station), and the target RAN node 104 can be a gNB (i.e., an NR base station), or vice versa.

[0060] There are various types of handover procedures. For example, a conditional handover (CHO) can be defined as a handover performed by UE 100 when one or more handover execution conditions are met. In other words, UE 100 (e.g., from source RAN node 104B) receives a handover command with a CHO configuration indicating one or more handover execution conditions, but UE 100 does not execute the handover command until one or more handover execution conditions are met. UE 100 can begin evaluating one or more handover execution conditions upon receiving the CHO configuration and stop evaluating one or more handover execution conditions once the handover is performed.

[0061] The advantage of CHO is that it improves mobility robustness by reducing the number of radio link failures and handover failures compared to traditional handover. This is achieved by decoupling the handover execution phase from the preparation phase, allowing UE 100 to receive the handover command early while the radio link of source cell 121 is still sufficient, and to perform the handover later when the radio link of target cell 122 is strong enough.

[0062] For example, CHO configuration can be included in an RRC reconfiguration message. The CHO configuration includes the configuration of multiple CHO candidate cells 122 generated by the candidate target RAN node(s) 104, and one or more handover execution conditions generated by the source RAN node(s) 104B. The one or more handover execution conditions may include, for example, CHO event A3 and / or CHO event A5. One or more reference signal types may be supported, and one or more trigger quantities can be configured to evaluate the CHO execution conditions for a given candidate cell 122. The one or more trigger quantities may include, for example, Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), and / or Signal-to-Interference-plus-Noise Ratio (SINR).

[0063] CHO event A3 means that the trigger amount (e.g., RSRP, RSRQ, and / or SINR) of CHO candidate cell 122 indicated in the CHO configuration exceeds the trigger amount (e.g., RSRP, RSRQ, and / or SINR) of source cell 121 by an offset during a certain trigger time (TTT) period.

[0064] CHO event A5 means that the triggering amount of source cell 121 has fallen below the first threshold, and the triggering amount of CHO candidate cell 122 indicated in the CHO configuration has exceeded the second threshold during a certain TTT period.

[0065] Dual connectivity (DC) enables UE 100 to connect to two cell groups simultaneously: the primary cell group (MCG) and the secondary cell group (SCG). The MCG and SCG can be controlled by different RAN nodes. The MCG and SCG can be based on different radio access technologies (e.g., LTE and NR), or they can be based on the same radio access technology (e.g., NR).

[0066] MCG is a group of serving cells controlled by the Master Node (MN). The Master Node is the RAN node that provides control plane connectivity to the core network 110. An MCG includes a Primary Cell (PCell), which is the primary serving cell of the MCG, and optionally includes one or more Secondary Cells (SCells). A PCell is a cell operating on a primary frequency that can be used for initial access under the MCG. An SCell is a cell operating on a secondary frequency that can be configured once an RRC connection is established, and can be used to provide additional radio resources.

[0067] An SCG is a group of serving cells controlled by a secondary node (SN). A secondary node is a RAN node that provides additional resources to the UE 100. An SCG includes primary and secondary cells (PSC cells), which are the primary serving cells of the SCG, and optionally includes one or more SCells. A PSCell is a cell that can be used for initial access under the SCG.

[0068] To change from one PSCell to another, a PSCell change process known as Conditional Primary / Secondary Cell Change (CPC) can be performed when one or more PSCell execution conditions are met.

[0069] To add a new PSCell, a PSCell addition process called Conditional Primary / Secondary Cell Addition (CPA) can be performed when one or more PSCell addition conditions are met.

[0070] For NR version 18, the goal is to specify a CHO that includes the target MCG and the target SCG, and to specify a CHO that includes the target MCG and the candidate SCG for CPC or CPA in NR dual connectivity (the CHO that includes the target MCG and the SCG can be used as a baseline for this).

[0071] During handovers between gNBs, between DUs, or between MNs or SNs via DC CHO, the RRC configuration at UE 100 in source cell 121 may not be supported in target cell 122. To address this, incremental configuration can be supported, allowing configurations that need to be released or replaced to be processed as part of the handover command.

[0072] The source RAN node 104B can transmit the source cell configuration (sourceConfig) information element in the HandoverPreparationInformation to the target RAN node 104, so that the target RAN node 104 can compare the target cell configuration it wants to apply at UE 100 (as part of the handover command) with the source cell configuration currently configured at UE 100 in the source cell 121.

[0073] However, in the following situations, it may not be permissible for the UE 100 to make any changes to the configuration of the established Data Radio Bearer (DRB): changing the Radio Link Control (RLC) mode at the target RAN node 104; changing pdcp-SN-SizeUL or pdcp-SN-SizeDL at the target RAN node 104; changing the IntegrityProtection information element at the target RAN node 104; setting cipheringDisabled in the PDCP-Config information element at the source RAN node 104B and the target RAN node 104 does not want to set it (or vice versa); requiring a change to sdap-HeaderDL / UL at the target RAN node 104; and / or having a change from E-UTRA to NR PDCP (or vice versa).

[0074] To handle any of the above configuration mismatches, the following two options can be applied: 1) Target RAN node 104 performs a fullConfig switch, or 2) Target RAN node 104 triggers DRB release and addition as part of the switch command.

[0075] The Data Radio Bearer (DRB) is a logical channel established between the UE 100 and a RAN node (e.g., source RAN node 104B or target RAN node 104) for the transmission of user data. The DRB handles actual user plane traffic, which can include data packets for various types of services, such as Internet browsing, Voice over Internet Protocol (IP), video streaming, etc.

[0076] DRB release refers to the process of terminating the existing data radio bearer between UE 100 and the RAN node (e.g., source RAN node 104B). When a DRB is released, the resources allocated for that specific DRB are released, and the logical channel is shut down. For example, during a handover scenario, if the existing DRB is not needed in the target cell 122, it can be released.

[0077] DRB addition refers to the establishment of a new data radio bearer. When a DRB is added, network resources are allocated to the DRB, and a logical channel is created to carry user plane data. For example, during a handover scenario, a new DRB can be added in target cell 122 based on active services and available resources.

[0078] During handover, when UE 100 performs a DRB release and adds the same DRB identifier, UE 100 may lose the mapping between the serving radio bearer (used as an example of a DRB identifier) ​​and the logical channel identifier (LCID). This mapping can be configured to UE 100 as part of the RLC-BearerConfig in the CellGroupConfig generated by DU 105 of target RAN node 104. An example of RLC-BearerConfig is provided below: RLC-BearerConfig ::=SEQUENCE{ logicalChannelIdentity LogicalChannelIdentity , servedRadioBearerCHOICE{ srb-Identity SRB-Identity , drb-Identity DRB-Identity }OPTIONAL, -- Cond LCH-SetupOnly reestablishRLCENUMERATED{ true}OPTIONAL, -- Need N rlc-Config RLC-Config OPTIONAL -- Cond LCH-Setup mac-LogicalChannelConfig LogicalChannelConfig OPTIONAL -- Cond LCH- Setup ..., [[ rlc-Config-v1610 RLC-Config-v1610 OPTIONAL -- Need R ]], [[ rlc-Config-v1700 RLC-Config-v1700 OPTIONAL -- Need R logicalChannelIdentityExt-r17 LogicalChannelIdentityExt-r17 OPTIONAL -- Cond LCH-SetupModMRB multicastRLC-BearerConfig-r17 MulticastRLC-BearerConfig-r17 OPTIONAL -- Cond LCH-SetupOnlyMRB servedRadioBearerSRB4-r17 SRB-Identity-v1700 OPTIONAL -- Need N ]] } cellGroupConfig includes Layer 1 and Layer 2 information required for UE 100 to access target cell 122. For example, cellGroupConfig may include physical (PHY), MAC, and RLC layer configurations, as well as public cell level information.

[0079] The LCID is a unique identifier used to distinguish different logical channels within the same connection between UE 100 and RAN nodes (e.g., source RAN node 104B or target RAN node 104). A logical channel is an abstract link that categorizes the data types being transmitted (such as control signaling or user plane data), and the LCID is used to specify which logical channel a particular data block should be mapped to during transmission.

[0080] An RLC bearer is an instance of the RLC protocol responsible for providing data delivery services over the air interface. The RLC bearer serves as a link-layer connection for transmitting data between the UE 100 and RAN nodes (e.g., source RAN node 104B or destination RAN node 104). Each RLC bearer has an LCID. The LCID is used to identify a specific logical channel within the RLC bearer. When the LCID is multiplexed or demultiplexed on a single RLC bearer, it is used at the Media Access Control (MAC) layer to indicate which logical channel a particular MAC Service Data Unit (SDU) belongs to. Therefore, the LCID serves as an identifier that enables the MAC layer to correctly map incoming and outgoing data to the appropriate RLC bearer for transmission or reception.

[0081] UE 100 can utilize the mapping between LCID and DRB identifiers to facilitate data packet routing to the UE's MAC layer. Similarly, DU 105 can utilize the mapping between LCID and DRB identifiers to facilitate data packet routing to the gNB's MAC layer. The DRB identifier is referred to as the "Serving Radio Bearer" in this mapping information. Each LCID needs to be mapped to the Serving Radio Bearer (DRB identifier) ​​at the DU to allow proper routing between the PDCP / RLC and MAC entities.

[0082] UE 100 may have a serving radio bearer with source cell 121, and this serving radio bearer is associated with or mapped to a certain LCID. When UE 100 must release the serving radio bearer with source cell 121 and add another serving radio bearer with target cell 122, the new serving radio bearer should be mapped to the same LCID of UE 100. CellGroupConfig can be used to achieve this.

[0083] To enable UE 100 to map the serving radio bearer to the LCID, RLC-BearerToRelease and RLC-BearerToAdd can be performed for the released and added DRBs.

[0084] For DRBs and Signalling Radio Bearers (SRBs), the network may not reassociate an already configured logical channel with another radio bearer. Therefore, a `servedRadioBearer` may not exist in this case. For Multicast Radio Bearers (MRBs), the network may not reassociate an already configured logical channel with a DRB, SRB, or another MRB (i.e., an MRB with another PDCP entity). Therefore, a multicast RLC-BearerConfig may not exist in this case. If a radio bearer is released and another radio bearer is added with the same radio bearer identity, it can be considered a new (different) radio bearer. Therefore, the network also releases the RLC bearers associated with the released radio bearer.

[0085] However, currently, the CU-CP of the target RAN node 104 cannot indicate to the DU of the target RAN node 104 that it is a DRB release and add scenario, so that the DU can generate a CellGroupConfig with RLC-BearerToRelease and RLC-BearerToAdd configurations in the handover command to remap the servedRadioBearer with the LCID.

[0086] In cases where the same DRB identifier is released and added, this could lead to a reset of the RLC configuration at UE 100 in order to reconfigure specific configurations such as RLC mode changes or PDCP SN size changes. The DU is unaware that the DRB is being released and added to UE 100, and therefore UE 100 loses its mapping to the existing LCID.

[0087] In theory, this can be solved by implementing appropriate UE implementations. However, this would only apply to future UEs, while the problem involves currently used UEs. Therefore, network-side solutions for the current UE implementations need to be considered.

[0088] When the target RAN node 104 decides to prepare an incremental configuration that includes the configuration that triggers DRB release and adds it to handle any potential configuration mismatch scenarios between the source cell configuration and the target cell configuration (e.g., the configuration mismatch scenarios listed above), some example embodiments can provide such a solution to address the above-mentioned problems.

[0089] Some example implementations can be applied to any mobility process, such as CHO (e.g., in single or dual connectivity), or selective activation of SCG or MCG.

[0090] However, the following description of some example embodiments uses the principles and terminology of 5G radio access technology, without limiting the example embodiments to 5G radio access technology.

[0091] The example implementation described below can help avoid fullConfig handover. Furthermore, the UE does not need to trigger an RRC rebuild because the mapping between the LCID and the servedRadioBearer is not lost. Additionally, the network does not need to perform RLC-BearerToRelease and AddMod for each UE undergoing handover.

[0092] Figure 2 A signal flow diagram according to an example embodiment is shown. In this example embodiment, during CHO preparation, if the target cell configuration prepared by the target RAN node 104 is inconsistent with the source cell configuration, the CU 108 (or CU-CP) of the target RAN node 104 can transmit an indication to enable the DU 105 of the target RAN node 104 to prepare a CellGroupConfig for DRB release and to add scenario processing for the affected DRB(multiple) DRB(s).

[0093] refer to Figure 2 At position 201, UE 100 transmits one or more measurement reports to source RAN node 104B. For example, source RAN node 104 may be the gNB currently serving UE 100. One or more measurement reports may include, for example, reference signal received power (RSRP), reference signal received quality (RSRQ), and / or signal-to-noise ratio (SNR) measurements of serving cell (source cell) 121 and one or more neighboring cells 122.

[0094] At 202, based on one or more measurement reports, source RAN node 104B determines to prepare for conditional handover for UE 100, wherein neighboring cell 122 is determined as the target cell for conditional handover.

[0095] At point 203, based on the determination at 202, source RAN node 104B transmits a handover request message to CU 108 of target RAN node 104 (e.g., another gNB) controlling target cell 122, wherein the handover request message includes the source cell configuration of source cell 121 for handover. For example, the source cell configuration may be included in the 'HandoverPreparationInformation' information element of the handover request message. CU 108 of target RAN node 104 receives the handover request message.

[0096] The source cell configuration refers to the set of parameters and resource allocations pre-established for UE 100 in source cell 121 prior to initiating the handover procedure. For example, the source cell configuration may include at least one of the following: Radio Resource Control (RRC) settings, resource block allocations, one or more radio bearers, and one or more channel configurations. In other words, the source cell configuration refers to all configurations of UE 100 contained in the RRC configuration of UE 100 in source cell 121, as encapsulated in the configurations directed towards UE 100 during RRC establishment and subsequent RRC reconfiguration.

[0097] At position 204, based on the received handover request message, CU 108 of target RAN node 104 performs admission control to determine whether target cell 122 has sufficient resources to accommodate the accessing UE 100 without compromising the quality of service (QoS) of existing UEs in target cell 122. The admission control process may involve evaluating various parameters, including the available bandwidth, signal strength, and current cell load of target cell 122.

[0098] In addition, CU 108 can perform bearer context establishment to establish or reconfigure bearers for user plane and control plane services carried by UE 100.

[0099] CU 108 then prepares the target cell configuration for UE 100. The target cell configuration refers to the set of parameters and resource allocations that are pre-established or dynamically configured in target cell 122 after handover is completed to suit UE 100. For example, the target cell configuration may include at least one of the following: Radio Resource Control (RRC) settings, resource block allocation, one or more radio bearers, and one or more channel configurations.

[0100] At 205, the CU 108 of the target RAN node 104 compares the prepared target cell configuration with the source cell configuration to identify whether any accepted data radio bearers will require DRB release and add processing. In other words, the target RAN node 104 determines whether the target cell configuration corresponds to or is consistent with the source cell configuration in order to identify any mismatch between the target cell configuration and the source cell configuration that would require triggering DRB release and add.

[0101] Examples of such mismatches may include, but are not limited to: changing the radio link control (RLC) mode at the target RAN node 104; changing pdcp-SN-SizeUL or pdcp-SN-SizeDL at the target RAN node 104; changing the integrity protection information element at the target RAN node 104; setting cipheringDisabled in the PDCP configuration information element at the source RAN node 104B and the target RAN node 104 does not want to set it (or vice versa); needing to change sdap-HeaderDL / UL at the target RAN node 104; and / or having a change from E-UTRA to NR PDCP (or vice versa).

[0102] At point 206, based on the determination that the target cell configuration does not correspond to the source cell configuration (i.e., if there are one or more mismatches between the configurations), the CU 108 of the target RAN node 104 determines that a handover release and the addition of at least one data radio bearer are required for the UE 100. In other words, the CU 108 identifies the need to trigger a DRB release and add at least one data radio bearer based on identifying one or more mismatches between the target cell configuration and the source cell configuration.

[0103] At 207, CU 108 of target RAN node 104 transmits an indication to DU 105 of target RAN node 104, indicating the release and addition of at least one data radio bearer for handover of user equipment. DU 105 receives the indication. For example, the indication can be transmitted in a UE context establishment request message via the F1 Application Protocol (F1AP) to notify DU 105 to prepare or update the cell group configuration (CellGroupConfig) for DRB release and addition.

[0104] In other words, CU 108 decides to release one or more DRBs and add them back, and then CU 108 notifies DU 105 of the decision, so that DU 105 can release and add back the corresponding (multiple) RLC bearers.

[0105] As an example, the indication may include a flag for each data radio bearer to be released and added, indicating the triggering of the release and addition of the radio link control bearer associated with the data radio bearer to be released and added. In other words, the flag may instruct DU 105 to trigger RLC-BearerToRelease and RLC-BearerToAdd for at least one RLC bearer associated with the serving radio bearer identifier of at least one data radio bearer. The flag may be included in the 'DRBs-ToSetupItem' information element, for example, in a UE context establishment request message. For each DRB that is released and added back, the flag may be included in each DRB-ToBeSetupItem information element.

[0106] RLC-BearerToRelease is a command indicating that one or more existing RLC bearers need to be terminated or released. This operation involves releasing radio resources allocated to one or more RLC bearers, including any associated caches and state information on the UE 100 and the network side (e.g., at the source RAN node 104B).

[0107] RLC-BearerToAdd is a command that indicates one or more new RLC bearers should be created. This operation involves allocating the necessary radio resources and establishing an appropriate configuration to handle one or more new RLC bearers.

[0108] At 208, based on this instruction, DU 105 of target RAN node 104 determines or identifies at least one radio link control bearer associated with at least one data radio bearer, and prepares a cell group configuration for handover release and addition of at least one radio link control bearer associated with at least one data radio bearer for UE 100. In other words, DU 105 uses this instruction to prepare a CellGroupConfig with a configuration for triggering RLC-BearerToRelease and RLC-BearerToAdd for at least one RLC bearer associated with the serving radio bearer identifier of at least one DRB to be released and added.

[0109] At position 209, DU 105 of target RAN node 104 transmits a prepared or updated cell group configuration to CU 108 of target RAN node 104, wherein the cell group configuration indicates at least one radio link control bearer to be released and added. For example, DU 105 may transmit the cell group configuration in the information element of "DU to CU RRC information" in the UE context establishment response message. CU 108 receives the cell group configuration.

[0110] At 210, CU 108 of target RAN node 104 transmits a cell group configuration to source RAN node 104B of control source cell 121, wherein the cell group configuration indicates at least one radio link control bearer to be released and added. For example, CU 108 may transmit a handover request confirmation message to source RAN node 104 including a CHO configuration, wherein the CHO configuration includes a handover command for performing a handover of UE 100 from source cell 121 to target cell 122, and wherein the handover command includes the cell group configuration. The handover command may be included in the information element of a “target NG-RAN node to source NG-RAN node transparent container” in, for example, the handover request confirmation message. Source RAN node 104B receives this message.

[0111] When encoding handover commands, CU 108 can include DRB release and add commands (i.e., commands to release and add at least one data radio bearer) in the "RadioBearerConfig" information element of the handover command. The handover command also has another part, which is the cell group configuration encoded by DU 105. In the cell group configuration, DU 105 can encode RLC bearer release and add commands corresponding to the DRB(s) to be released and added back.

[0112] At 211, for example, source RAN node 104B applies CHO configuration (which includes a handover command) at UE 100 via an RRC reconfiguration message. The CHO configuration may include or indicate one or more conditions for performing the handover.

[0113] At position 212, UE 100 transmits an RRC reconfiguration complete message to source RAN node 104B to indicate that the CHO configuration has been successfully applied.

[0114] At 213, UE 100 detects that one or more conditions for performing a handover are met, and therefore UE 100 initiates a handover from source cell 121 to target cell 122.

[0115] At 214, UE 100 performs a Random Access Channel (RACH) procedure with DU 105 of target RAN node 104. The RACH procedure is used for initial access to connect UE 100 to target cell 122.

[0116] At 215, when UE 100 connects to target cell 122 controlled by target RAN node 104 during handover, UE 100 releases and adds at least one data radio bearer based on the handover command. That is, UE 100 releases (multiple) DRBs established for it in source cell 121, and UE 100 can add back the same (multiple) DRBs in target cell 122.

[0117] As part of the DRB release and addition at UE 100, UE 100 releases and adds at least one radio link control bearer associated with at least one data radio bearer based on the cell group configuration received in the handover command.

[0118] Figure 3 A signal flow diagram according to an example embodiment is shown. In this example embodiment, the network transmits an indication to UE 100 to indicate that the released and added DRBs are the same DRBs. UE 100 can use this indication to avoid resetting the mapping between the LCID and the serving radio bearer identifier.

[0119] refer to Figure 3 At point 301, UE 100 transmits one or more measurement reports to source RAN node 104B. For example, source RAN node 104 may be the gNB currently serving UE 100. One or more measurement reports may include, for example, reference signal received power (RSRP), reference signal received quality (RSRQ), and / or signal-to-noise ratio (SNR) measurements of serving cell (source cell) 121 and one or more neighboring cells 122.

[0120] At 302, based on one or more measurement reports, source RAN node 104B determines to prepare for conditional handover for UE 100, wherein neighboring cell 122 is determined as the target cell for conditional handover.

[0121] At point 303, based on the determination at 302, source RAN node 104B transmits a handover request message to the CU 108 of the target RAN node 104 (e.g., another gNB) controlling target cell 122, wherein the handover request message includes the source cell configuration of the source cell 121 for handover. For example, the source cell configuration may be included in the 'HandoverPreparationInformation' information element of the handover request message. The CU 108 of the target RAN node 104 receives the handover request message.

[0122] Source cell configuration refers to the set of parameters and resource allocations pre-established for UE 100 in source cell 121 before initiating the handover procedure. For example, source cell configuration may include at least one of the following: Radio Resource Control (RRC) settings, resource block allocation, one or more radio bearers, and one or more channel configurations.

[0123] At 304, based on the received handover request message, CU 108 of target RAN node 104 performs admission control to determine whether target cell 122 has sufficient resources to accommodate the accessing UE 100 without compromising the quality of service (QoS) of existing UEs in target cell 122. The admission control process may involve evaluating various parameters, including the available bandwidth, signal strength, and current cell load of target cell 122.

[0124] In addition, CU 108 can perform bearer context establishment to establish or reconfigure bearers for user plane and control plane services carried by UE 100.

[0125] CU 108 then prepares the target cell configuration for UE 100. The target cell configuration refers to the set of parameters and resource allocations that are pre-established or dynamically configured in target cell 122 after handover is completed to suit UE 100. For example, the target cell configuration may include at least one of the following: Radio Resource Control (RRC) settings, resource block allocation, one or more radio bearers, and one or more channel configurations.

[0126] At 305, the CU 108 of the target RAN node 104 compares the prepared target cell configuration with the source cell configuration to identify whether any accepted data radio bearers will require DRB release and add processing. In other words, the target RAN node 104 determines whether the target cell configuration corresponds to or is consistent with the source cell configuration in order to identify any mismatch between the target cell configuration and the source cell configuration that would require triggering DRB release and add.

[0127] Examples of such mismatches may include, but are not limited to: changing the radio link control (RLC) mode at the target RAN node 104; changing pdcp-SN-SizeUL or pdcp-SN-SizeDL at the target RAN node 104; changing the integrity protection information element at the target RAN node 104; setting cipheringDisabled in the PDCP configuration information element at the source RAN node 104B and the target RAN node 104 does not want to set it (or vice versa); needing to change sdap-HeaderDL / UL at the target RAN node 104; and / or having a change from E-UTRA to NR PDCP (or vice versa).

[0128] At point 306, based on the determination that the target cell configuration does not correspond to the source cell configuration (i.e., if there are one or more mismatches between the configurations), the CU 108 of the target RAN node 104 determines that a handover release and the addition of at least one data radio bearer are required for the UE 100. In other words, the CU 108 identifies the need to trigger a DRB release and add at least one data radio bearer based on identifying one or more mismatches between the target cell configuration and the source cell configuration.

[0129] At 307, CU 108 of target RAN node 104 transmits a UE context establishment request message to DU 105 of target RAN node 104 for establishing or modifying the UE context at DU 105, and thus facilitates the seamless transition of UE 100 from source cell 121 to target cell 122.

[0130] At 308, DU 105 of target RAN node 104 transmits a UE context establishment response message to CU 108 of target RAN node 104 as an acknowledgment, confirming that DU 105 has successfully established or modified the UE context according to the parameters and configuration specified in the UE context establishment request message.

[0131] At point 309, when at least one data radio bearer is released and added during handover, the CU 108 of the target RAN node 104 transmits an indication to the source RAN node 104B of the control source cell 121, instructing the UE 100 to maintain a pre-configured mapping between at least one logical channel identifier of at least one radio link control bearer and at least one serving radio bearer identifier of at least one data radio bearer. For example, the CU 108 may transmit a handover request confirmation message including a CHO configuration, wherein the CHO configuration includes a handover command for performing a handover of the UE 100 from the source cell 121 to the target cell 122, and wherein the handover command includes the indication. For example, the indication may be included in at least one of the following: a 'DRB-ToReleaseList' information element or a 'DRB-ToAddModItem' information element, which may be included in the 'RadioBearerConfig' information element of the handover command. The source RAN node 104B receives the message.

[0132] When encoding a handover command, the CU 108 may include DRB release and add commands (i.e., commands to release and add at least one data radio bearer) in the “RadioBearerConfig” information element of the handover command.

[0133] DRB-ToReleaseList is a list specifying at least one data radio bearer to be released during handover. Each DRB can be identified by its DRB identifier.

[0134] DRB-ToAddModItem is an information element that describes parameters used to add or modify data radio bearers. It can include various sub-elements that define the DRB configuration, such as logical channel configuration, packet data convergence protocol (PDCP) configuration, and radio link control (RLC) configuration.

[0135] At 310, for example, source RAN node 104B applies CHO configuration (which includes a handover command and the indication) at UE 100 via an RRC reconfiguration message. CHO configuration may include or indicate one or more conditions for performing a handover.

[0136] This instruction can be included in the DRB-ToReleaseList and / or DRB-ToAddModItem information elements within the RRC reconfiguration message.

[0137] At 311, UE 100 transmits an RRC reconfiguration complete message to source RAN node 104B to indicate that the CHO configuration has been successfully applied.

[0138] At 312, UE 100 detects that one or more conditions for performing a handover are met, and therefore UE 100 initiates a handover from source cell 121 to target cell 122.

[0139] At 313, UE 100 performs a Random Access Channel (RACH) procedure with DU 105 of target RAN node 104. The RACH procedure is used for initial access to connect UE 100 to target cell 122.

[0140] At 314, based on this instruction, when at least one data radio bearer is released and added during handover, UE100 maintains or retains a pre-configured mapping between at least one logical channel identifier and at least one identifier (e.g., serving radio bearer) of at least one data radio bearer.

[0141] UE 100 can apply maintained mappings to route data packets after handover.

[0142] At 315, as part of the DRB release and addition at the UE, when the UE 100 connects to the target cell 122 controlled by the target RAN node 104 during handover, the DU 105 of the target RAN node 104 adds at least one radio link control bearer associated with at least one data radio bearer.

[0143] Figure 4 The diagram illustrates the method based on... Figure 12 The flowchart illustrates an example embodiment of the method performed by the apparatus 1200 depicted. For example, the apparatus 1200 may be a central unit 108, such as a radio access network node (target RAN node) 104 (e.g., gNodeB) that controls a target cell 122, or an apparatus that includes or is included in the central unit 108.

[0144] refer to Figure 4 In block 401, device 1200 determines whether the target cell configuration of the target cell 122 for handover of user equipment 100 corresponds to the source cell configuration of the source cell 121 for handover of user equipment 100.

[0145] In block 402, based on the determination that the target cell configuration does not correspond to the source cell configuration, device 1200 determines to release and add at least one data radio bearer for the handover of user equipment 100.

[0146] In block 403, device 1200 performs at least one of the following: transmitting an instruction to the distributed unit 105 of radio access network node 104 of control target cell 122, the instruction being used to instruct the release and addition of at least one data radio bearer for handover of user equipment 100; or transmitting an instruction to radio access network node 104B of control source cell 121, the instruction being used to instruct user equipment 100, during handover, when releasing and adding at least one data radio bearer, to maintain a pre-configured mapping between at least one logical channel identifier of at least one radio link control bearer and at least one serving radio bearer identifier of at least one data radio bearer.

[0147] For example, the instruction transmitted to the distributed unit 105 may include a flag for each data radio bearer to be released and added, which indicates triggering the release and addition of the radio link control bearer associated with the data radio bearer to be released and added.

[0148] Apparatus 1200 can receive cell group configuration from distributed unit 105 based on an instruction transmitted to distributed unit 105 for handover release and addition of at least one radio link control bearer associated with at least one data radio bearer for user equipment. Apparatus 1200 can transmit cell group configuration to radio access network node 104B of control source cell 121, wherein the cell group configuration indicates at least one radio link control bearer to be released and added.

[0149] Figure 5 The diagram illustrates the method based on... Figure 11The flowchart illustrates an example embodiment of the method performed by the apparatus 1100 depicted. For example, apparatus 1100 may be an apparatus such as or including or being included in a distributed unit 105 of a radio access network node (target RAN node) 104 (such as gNodeB) controlling target cell 122.

[0150] refer to Figure 5 In block 501, device 1100 receives an instruction from central unit 108 of radio access network node 104, the instruction indicating the release of a handover for user equipment 100 and the addition of at least one data radio bearer. In other words, the instruction can indicate at least one data radio bearer to be released and added for the handover of user equipment 100.

[0151] For example, the indication may include a flag for each data radio bearer to be released and added, which indicates the triggering of the release and addition of the radio link control bearer associated with the data radio bearer to be released and added.

[0152] In block 502, device 1100 identifies or identifies at least one radio link control bearer associated with the at least one data radio bearer.

[0153] Apparatus 1100 can prepare a cell group configuration based on this instruction for handover release and addition of at least one radio link control bearer associated with at least one data radio bearer for user equipment 100. Apparatus 1100 can transmit the cell group configuration to central unit 108, wherein the cell group configuration indicates at least one radio link control bearer to be released and added.

[0154] In block 503, device 1100 prepares cell group configuration based on the instruction for handover release of user equipment 100 and addition of at least one radio link control bearer associated with at least one data radio bearer.

[0155] In block 504, device 1100 transmits cell group configuration to central unit 108, wherein the cell group configuration indicates at least one radio link control bearer to be released and added.

[0156] Figure 6 The diagram illustrates the method based on... Figure 10 The flowchart illustrates an example embodiment of a method performed by the device 1000 depicted herein. For example, the device 1000 may be, or may include, or may be included in user equipment (UE) 100, 102.

[0157] Figure 7 The diagram illustrates the method based on... Figure 12The flowchart illustrates an example embodiment of the method performed by the apparatus 1200 depicted. For example, the apparatus 1200 may be a central unit 108, such as a radio access network node (target RAN node) 104 (e.g., gNodeB) that controls a target cell 122, or an apparatus that includes or is included in the central unit 108.

[0158] refer to Figure 7 In block 701, device 1200 determines that the target cell configuration of the target cell 122 for handover of user equipment 100 does not correspond to the source cell configuration of the source cell 121 for handover of user equipment 100, wherein the target cell 122 is controlled by gNodeB 104.

[0159] In block 702, based on the determination that the target cell configuration does not correspond to the source cell configuration, device 1200 determines to release and add at least one data radio bearer for the handover of user equipment 100.

[0160] In block 703, device 1200 performs at least one of the following: transmits a UE context establishment request message to the distributed unit 105 of gNodeB 104, the UE context establishment request message including an indication to instruct the preparation of cell group configuration for handover release and addition of at least one radio link control bearer associated with at least one data radio bearer for user equipment 100; or transmits a handover command to the source gNodeB 104B controlling source cell 121 for performing a handover from source cell 121 to target cell 122, wherein the handover command includes an indication to instruct user equipment 100 to maintain a pre-configured mapping between at least one logical channel identifier of at least one radio link control bearer and at least one serving radio bearer identifier of at least one data radio bearer when releasing and adding at least one data radio bearer during handover.

[0161] For example, the instruction transmitted to the distributed unit 105 may include a flag for each data radio bearer to be released and added, which indicates the triggering of RLC-BearerToRelease and RLC-BearerToAdd for releasing and adding the radio link control bearer associated with the data radio bearer to be released and added.

[0162] This flag can be included in the 'DRBs-ToBeSetupItem' information element of the UE context setup request message.

[0163] The apparatus 1200 can receive a UE context establishment response message from the distributed unit 105 based on transmitting a UE context establishment request message to the distributed unit 105. The UE context establishment response message includes a prepared cell group configuration for handover release for user equipment 100 and adding at least one radio link control bearer associated with at least one data radio bearer.

[0164] The device 1200 can transmit a handover request confirmation message to the source gNodeB 104B, including a prepared cell group configuration, wherein the prepared cell group configuration indicates at least one radio link control bearer to be released and added.

[0165] The cell group configuration received from the distributed unit 105 can be included in the information element of the 'DU to CU RRC information' in the UE context establishment response message.

[0166] The cell group configuration transmitted to the source gNodeB can be included in the information element of the 'Target NG-RAN Node to Source NG-RAN Node Transparent Container' in the handover request confirmation message.

[0167] Instructions for user equipment 100 to maintain pre-configured mappings may include at least one of the following: a 'DRB-ToReleaseList' information element or a 'DRB-ToAddModItem' information element of a switching command.

[0168] Figure 8 The diagram illustrates the method based on... Figure 11 The flowchart illustrates an example embodiment of the method performed by the apparatus 1100 depicted. For example, apparatus 1100 may be an apparatus such as or including or being included in a distributed unit 105 of a radio access network node (target RAN node) 104 (such as gNodeB) controlling target cell 122.

[0169] refer to Figure 8 In block 801, device 1100 receives a UE context establishment request message from central unit 108 of gNodeB 104. The UE context establishment request message includes an indication to prepare cell group configuration for handover release for user equipment 100 and addition of at least one radio link control bearer associated with at least one data radio bearer.

[0170] In block 802, device 1100 identifies or identifies the at least one radio link control bearer associated with the at least one data radio bearer.

[0171] In block 803, device 1100 prepares cell group configuration based on the instruction for handover release of user equipment 100 and addition of at least one radio link control bearer associated with at least one data radio bearer.

[0172] In block 804, device 1100 transmits a UE context establishment response message to the central unit, including a prepared cell group configuration, wherein the prepared cell group configuration indicates at least one radio link control bearer to be released and added.

[0173] For example, the instruction may include a flag for each data radio bearer to be released and added, indicating the triggering of RLC-BearerToRelease and RLC-BearerToAdd to release and add the radio link control bearer associated with each data radio bearer to be released and added. The prepared cell group configuration may include a configuration to trigger RLC-BearerToRelease and RLC-BearerToAdd to release and add each radio link control bearer associated with each data radio bearer to be released and added.

[0174] Figure 9 The diagram illustrates the method based on... Figure 10 The flowchart illustrates an example embodiment of a method performed by the device 1000 depicted herein. For example, the device 1000 may be, or may include, or may be included in user equipment (UE) 100, 102.

[0175] refer to Figure 9 In block 901, device 1000 receives from gNodeB 104B a handover command for performing a handover from source cell 121 to target cell 122, wherein the handover command includes an indication for indicating a pre-configured mapping between at least one logical channel identifier and at least one serving radio bearer identifier of at least one data radio bearer for releasing and adding the at least one data radio bearer during the handover.

[0176] In block 902, during handover when releasing and adding the at least one data radio bearer, device 1000 maintains a pre-configured mapping between at least one logical channel identifier and at least one serving radio bearer identifier based on the instruction.

[0177] In block 903, device 1000 applies the maintained mapping to route data packets after handover. This is achieved through... Figures 2 to 9The described boxes, related functions, and information exchanges (messages) do not have an absolute temporal order, and some of them may be executed simultaneously or in a different order than described. Other functions may also be executed between or within them, and may transfer other information and / or apply other rules. Some blocks or parts of blocks or one or more messages may also be omitted or replaced by the corresponding blocks or parts of blocks or one or more messages.

[0178] The above has been approved. Figures 2 to 9 The described boxes, related functions, and information exchanges (messages) do not have an absolute temporal order, and some of them may be executed simultaneously or in a different order than described. Other functions may also be executed between or within them, and may transfer other information and / or apply other rules. Some blocks or parts of blocks or one or more messages may also be omitted or replaced by the corresponding blocks or parts of blocks or one or more messages.

[0179] As used herein, “at least one of the following: a list of two or more elements” and “at least one of the following: a list of two or more elements” and similar wording (where the list of two or more elements is connected by “and” or “or”) means at least any one of the elements, or at least any two or more of the elements, or at least all of the elements.

[0180] Figure 10 An example of a device 1000 is shown, which includes components for performing one or more of the example embodiments described above. For example, device 1000 may be a device such as, or including, or incorporated in user equipment (UE) 100, 102.

[0181] Apparatus 1000 may include circuitry or chipsets suitable for implementing one or more of the example embodiments described above. For example, apparatus 1000 may include at least one processor 1010. At least one processor 1010 interprets instructions (e.g., computer program instructions) and processes data. At least one processor 1010 may include one or more programmable processors. At least one processor 1010 may include programmable hardware with embedded firmware and may alternatively or additionally include one or more application-specific integrated circuits (ASICs).

[0182] At least one processor 1010 is coupled to at least one memory 1020. The at least one processor is configured to read data from and write data to the at least one memory 1020. The at least one memory 1020 may include one or more memory cells. Memory cells may be volatile or non-volatile. It should be noted that one or more non-volatile memory cells and one or more volatile memory cells may be present, or alternatively, one or more non-volatile memory cells, or alternatively, one or more volatile memory cells. Volatile memory may be, for example, random access memory (RAM), dynamic random access memory (DRAM), or synchronous dynamic random access memory (SDRAM). Non-volatile memory may be, for example, read-only memory (ROM), programmable read-only memory (PROM), electrically erasable programmable read-only memory (EEPROM), flash memory, optical storage, or magnetic storage. Generally, memory may be referred to as a non-transitory computer-readable medium. As used herein, the term "non-transitory" is a limitation on the medium itself (i.e., tangible, not tactile), rather than a limitation on the persistence of data storage (e.g., RAM and ROM). At least one memory 1020 stores computer-readable instructions that are executed by at least one processor 1010 to perform one or more of the example embodiments described above. For example, non-volatile memory stores computer-readable instructions, and at least one processor 1010 uses volatile memory to execute instructions for temporary storage of data and / or instructions. Computer-readable instructions may refer to computer program code.

[0183] Computer-readable instructions may have been pre-stored in at least one memory 1020, or alternatively or additionally, they may be received by the device via an electromagnetic carrier signal and / or copied from a physical entity such as a computer program product. Execution of the computer-readable instructions by at least one processor 1010 causes the device 1000 to perform one or more of the methods and / or blocks described above. That is, at least one processor and at least one memory storing the instructions can provide components for providing or causing execution of any of the methods and / or blocks described above.

[0184] In the context of this document, "memory" or "computer-readable medium" can refer to any non-transitory medium or device that can contain, store, communicate, propagate, or transmit instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer. As used herein, the term "non-transitory" is a limitation on the medium itself (i.e., tangible, not tactile) rather than a limitation on the persistence of data storage (e.g., RAM and ROM).

[0185] The device 1000 may also include or be connected to the input unit 1030. The input unit 1030 may include one or more interfaces for receiving input. The one or more interfaces may include, for example, one or more temperature, motion and / or orientation sensors, one or more cameras, one or more accelerometers, one or more microphones, one or more buttons and / or one or more touch detection units. In addition, the input unit 1030 may include interfaces to which external devices can be connected.

[0186] The device 1000 may also include an output unit 1040. The output unit may include or be connected to one or more displays capable of displaying visual content, such as a light-emitting diode (LED) display, a liquid crystal display (LCD), and / or a liquid crystal on silicon (LCoS) display. The output unit 1040 may also include one or more audio outputs. The one or more audio outputs may be, for example, speakers.

[0187] Device 1000 also includes a connectivity unit 1050. The connectivity unit 1050 enables wireless connectivity to one or more external devices. The connectivity unit 1050 includes at least one transmitter and at least one receiver that can be integrated into or connected to the device 1000. The at least one transmitter includes at least one transmitting antenna, and the at least one receiver includes at least one receiving antenna. The connectivity unit 1050 may include an integrated circuit or a set of integrated circuits that provide wireless communication capabilities to the device 1000. Alternatively, the wireless connection may be a hardwired application-specific integrated circuit (ASIC). The connectivity unit 1050 may also provide means for performing at least some of the blocks or functions of one or more of the above example embodiments. The connectivity unit 1050 may include one or more components controlled by a corresponding control unit, such as: a power amplifier, a digital front-end (DFE), an analog-to-digital converter (ADC), a digital-to-analog converter (DAC), a frequency converter, a (de)modulator, and / or encoder / decoder circuitry.

[0188] It should be noted that device 1000 may also include Figure 10 Various components are not shown. These components can be hardware components and / or software components.

[0189] Figure 11 An example of an apparatus 1100 is shown, comprising components for performing one or more of the example embodiments described above. For example, apparatus 1100 may be an apparatus such as, or including or being included in, a distributed unit 105 of a radio access network node (target RAN node) 104 (such as a gNodeB) controlling a target cell 122.

[0190] Device 1100 may include, for example, circuitry or chipsets suitable for implementing one or more of the example embodiments described above. Device 1100 may be an electronic device including one or more electronic circuits. Device 1100 may include communication control circuitry 1110 (such as at least one processor) and at least one memory 1120 storing instructions 1122, which, when executed by at least one processor, cause device 1100 to perform one or more of the example embodiments described above. Such instructions 1122 may, for example, include computer program code (software). At least one processor and at least one memory storing instructions may provide components for providing or causing the execution of any of the methods and / or blocks described above.

[0191] The processor is coupled to memory 1120. The processor is configured to read data from memory 1120 and write data to memory 1120. Memory 1120 may include one or more memory cells. Memory cells may be volatile or non-volatile. It should be noted that one or more non-volatile memory cells and one or more volatile memory cells may be present, or alternatively, one or more non-volatile memory cells, or alternatively, one or more volatile memory cells. Volatile memory may be, for example, random access memory (RAM), dynamic random access memory (DRAM), or synchronous dynamic random access memory (SDRAM). Non-volatile memory may be, for example, read-only memory (ROM), programmable read-only memory (PROM), electrically erasable programmable read-only memory (EEPROM), flash memory, optical storage, or magnetic storage. Generally, memory may be referred to as a non-transitory computer-readable medium. As used herein, the term "non-transitory" is a limitation on the medium itself (i.e., tangible, not tactile), rather than a limitation on the persistence of data storage (e.g., RAM and ROM). Memory 1120 stores computer-readable instructions that are executed by the processor. For example, non-volatile memory stores computer-readable instructions, and the processor uses volatile memory to execute instructions for temporary storage of data and / or instructions.

[0192] The computer-readable instructions may have been pre-stored in memory 1120, or alternatively or additionally, they may be received by the device via an electromagnetic carrier signal and / or copied from a physical entity such as a computer program product. Execution of the computer-readable instructions causes device 1100 to perform one or more of the functions described above.

[0193] The memory 1120 can be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and / or removable memory. The memory may include a configuration database for storing configuration data, such as a current list of neighboring cells, and, in some example embodiments, the structure of frames used in detected neighboring cells.

[0194] Device 1100 may also include or be connected to communication interface 1130, such as a radio unit, which includes hardware and / or software for establishing a communication connection with one or more wireless communication devices according to one or more communication protocols. Communication interface 1130 includes at least one transmitter (Tx) and at least one receiver (Rx), which may be integrated into device 1100 or connected to it. Communication interface 1130 may provide components for performing some of the blocks of the above-described example embodiments. Communication interface 1130 may include one or more components controlled by a corresponding control unit, such as: power amplifier, digital front end (DFE), analog-to-digital converter (ADC), digital-to-analog converter (DAC), frequency converter, (de)modulator, and / or encoder / decoder circuitry.

[0195] Communication interface 1130 provides the device with radio communication capabilities for communication in a wireless communication network. The communication interface may, for example, provide a radio interface to one or more UEs 100, 102. Communication interface 1130 may also provide a radio, cable, or fiber optic interface to the central unit 108 of the radio access network node 104.

[0196] The device 1100 may also include a scheduler 1140 configured to allocate radio resources. The scheduler 1140 may be configured together with the communication control circuitry 1110 or may be configured separately.

[0197] It should be noted that device 1100 may also include Figure 11 Various components are not shown. These components can be hardware components and / or software components.

[0198] Figure 12 An example of an apparatus 1200 is shown, comprising components for performing one or more of the example embodiments described above. For example, apparatus 1200 may be a central unit 108, such as a radio access network node (target RAN node) 104 (e.g., gNodeB) that controls a target cell 122, or an apparatus that includes or is included in the central unit 108.

[0199] Device 1200 may include, for example, circuitry or chipsets suitable for implementing one or more of the example embodiments described above. Device 1200 may be an electronic device or computing system including one or more electronic circuits. Device 1200 may include control circuitry 1210 (such as at least one processor) and at least one memory 1220 storing instructions 1222, which, when executed by at least one processor, cause device 1200 to perform one or more of the example embodiments described above. Such instructions 1222 may, for example, include computer program code (software). At least one processor and at least one memory storing instructions may provide components for providing or causing the execution of any of the methods and / or blocks described above.

[0200] The processor is coupled to memory 1220. The processor is configured to read data from memory 1220 and write data to memory 1220. Memory 1220 may include one or more memory cells. Memory cells may be volatile or non-volatile. It should be noted that one or more non-volatile memory cells and one or more volatile memory cells may be present, or alternatively, one or more non-volatile memory cells, or alternatively, one or more volatile memory cells. Volatile memory may be, for example, random access memory (RAM), dynamic random access memory (DRAM), or synchronous dynamic random access memory (SDRAM). Non-volatile memory may be, for example, read-only memory (ROM), programmable read-only memory (PROM), electrically erasable programmable read-only memory (EEPROM), flash memory, optical storage, or magnetic storage. Generally, memory may be referred to as a non-transitory computer-readable medium. As used herein, the term "non-transitory" is a limitation on the medium itself (i.e., tangible, not tactile), rather than a limitation on the persistence of data storage (e.g., RAM and ROM). Memory 1220 stores computer-readable instructions that are executed by the processor. For example, non-volatile memory stores computer-readable instructions, and the processor uses volatile memory to execute instructions for temporary storage of data and / or instructions.

[0201] The computer-readable instructions may have been pre-stored in memory 1220, or alternatively or additionally, they may be received by the device via an electromagnetic carrier signal and / or copied from a physical entity such as a computer program product. Execution of the computer-readable instructions causes the device 1200 to perform one or more of the functions described above.

[0202] The memory 1220 can be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and / or removable memory.

[0203] Device 1200 may also include or be connected to communication interface 1230, which includes hardware and / or software for implementing a communication connection according to one or more communication protocols. Communication interface 1230 may include at least one transmitter (Tx) and at least one receiver (Rx), which may be integrated into device 1200 or connected to it. Communication interface 1230 may provide components for performing some of the blocks of the above-described example embodiments. Communication interface 1230 may include one or more components controlled by a corresponding control unit, such as: a power amplifier, a digital front end (DFE), an analog-to-digital converter (ADC), a digital-to-analog converter (DAC), a frequency converter, a (de)modulator, and / or encoder / decoder circuitry.

[0204] Communication interface 1230 provides the device with the ability to communicate in a wireless communication network. Communication interface 1230 may provide, for example, radio, cable, or fiber optic interfaces to distributed unit 105 and / or one or more other RAN nodes 104B.

[0205] It should be noted that device 1200 may also include Figure 12 Various components are not shown. These components can be hardware components and / or software components.

[0206] As used in this application, the term "circuit" may refer to one or more of the following: a) a hardware circuit implementation (such as an implementation in analog and / or digital circuits only); and b) a combination of hardware circuits and software, such as (if applicable): i) a combination of (multiple) analog and / or digital hardware circuits with software / firmware, and ii) (multiple) hardware processors with any part of the software (including (multiple) digital signal processors, software, and (multiple) memories working together to enable a device such as a mobile phone to perform various functions); and c) (multiple) hardware circuits and / or (multiple) processors, such as (multiple) microprocessors or a portion thereof, which require software (e.g., firmware) to operate, but may be absent when operation is not required.

[0207] This definition of "circuit" applies to all uses of the term in this application (including in any claim). As another example, as used herein, the term "circuit" also encompasses only hardware circuitry or a processor (or multiple processors) or a portion thereof and its accompanying software and / or firmware implementation. The term "circuit" also encompasses, for example and if applicable to a particular claim element, baseband integrated circuits or processor integrated circuits for mobile devices or similar integrated circuits in servers, cellular network devices, or other computing or network devices.

[0208] The techniques and methods described herein can be implemented by various means. For example, these techniques can be implemented in hardware (one or more devices), firmware (one or more devices), software (one or more modules), or a combination thereof. For hardware implementation, the apparatus(s) of the example embodiments can be implemented within one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), graphics processing units (GPUs), processors, controllers, microcontrollers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. For firmware or software, the implementation can be executed by a module (e.g., a process, function, etc.) of at least one chipset that performs the functions described herein. Software code can be stored in memory cells and executed by a processor. Memory cells can be implemented within or outside the processor. In the latter case, as is known in the art, it can be communicatively coupled to the processor via various means. Additionally, as those skilled in the art will understand, the components of the systems described herein can be rearranged and / or supplemented by additional components to facilitate the implementation of the various aspects described herein, and they are not limited to the precise configurations illustrated in the given figures.

[0209] It will be apparent to those skilled in the art that, with advancements in technology, the inventive concept can be implemented in various ways within the scope of the claims. Embodiments are not limited to the exemplary embodiments described above, but can vary within the scope of the claims. Therefore, all words and expressions should be interpreted broadly, and they are intended to illustrate rather than limit the embodiments.

Claims

1. An apparatus comprising at least one processor and at least one memory, the at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to at least: Determine whether the target cell configuration of the target cell for the handover of the user equipment corresponds to the source cell configuration of the source cell for the handover of the user equipment; Based on the determination that the target cell configuration does not correspond to the source cell configuration, it is determined that at least one data radio bearer needs to be added for the handover release of the user equipment. as well as Perform at least one of the following: The distributed unit controlling the radio access network node of the target cell transmits an instruction to indicate the release and addition of at least one data radio bearer for the handover of the user equipment; or The radio access network node controlling the source cell transmits an instruction to instruct the user equipment to maintain a pre-configured mapping between at least one logical channel identifier of at least one radio link control bearer and at least one identifier of at least one data radio bearer when releasing and adding the at least one data radio bearer during the handover.

2. The apparatus of claim 1, wherein the indication transmitted to the distributed unit includes a flag for each data radio bearer to be released and added, the flag indicating the triggering of the release and addition of a radio link control bearer associated with the data radio bearer to be released and added.

3. The apparatus according to any of the preceding claims further comprises: Based on the instruction transmitted to the distributed unit, cell group configuration is received from the distributed unit for the handover release and addition of the at least one radio link control bearer associated with the at least one data radio bearer for the user equipment; and The cell group configuration is transmitted to the radio access network node controlling the source cell, wherein the cell group configuration indicates at least one radio link control bearer to be released and added.

4. The apparatus according to any of the preceding claims, wherein the apparatus includes a central unit for controlling the radio access network node of the target cell.

5. An apparatus comprising at least one processor and at least one memory, the at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to at least: Receive instructions from the central unit of the radio access network node regarding the handover release and addition of at least one data radio bearer for user equipment; Identify at least one radio link control bearer associated with the at least one data radio bearer; Based on the instructions, prepare a cell group configuration for the handover release of the user equipment and the addition of the at least one radio link control bearer associated with the at least one data radio bearer; as well as The cell group configuration is transmitted to the central unit, wherein the cell group configuration indicates at least one radio link control bearer to be released and added.

6. The apparatus of claim 5, wherein the apparatus comprises a distributed unit of the radio access network node.

7. An apparatus comprising at least one processor and at least one memory, the at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to at least: Receive an instruction from a radio access network node, the instruction indicating a pre-configured mapping between at least one logical channel identifier and at least one identifier of at least one data radio bearer for releasing and adding the at least one data radio bearer during handover; During the handover, when releasing and adding the at least one data radio bearer, the pre-configured mapping between the at least one logical channel identifier and the at least one identifier of the at least one data radio bearer is maintained based on the indication; as well as The maintained mapping is applied after the switch to route data packets.

8. The apparatus of claim 7, wherein the apparatus includes user equipment.

9. An apparatus comprising: A component for determining whether the target cell configuration of the target cell for handover to a user equipment corresponds to the source cell configuration of the source cell for handover to the user equipment; Components for determining, based on the determination that the target cell configuration does not correspond to the source cell configuration, to release the handover for the user equipment and add at least one data radio bearer; as well as Components used to perform at least one of the following: The distributed unit controlling the radio access network node of the target cell transmits an instruction to indicate the release and addition of at least one data radio bearer for the handover of the user equipment; or The radio access network node controlling the source cell transmits an instruction to instruct the user equipment to maintain a pre-configured mapping between at least one logical channel identifier of at least one radio link control bearer and at least one identifier of at least one data radio bearer when releasing and adding the at least one data radio bearer during the handover.

10. An apparatus comprising: A component for receiving instructions from the central unit of a radio access network node to release and add at least one data radio bearer for a user equipment during handover. Components for determining at least one radio link control bearer associated with the at least one data radio bearer; Components for preparing cell group configuration based on the indication for handover release and adding at least one radio link control bearer associated with at least one data radio bearer for the user equipment; as well as Components for transmitting the cell group configuration to the central unit, wherein the cell group configuration indicates at least one radio link control bearer to be released and added.

11. An apparatus comprising: Components for receiving indications from radio access network nodes, the indications indicating a pre-configured mapping between at least one logical channel identifier and at least one identifier of at least one data radio bearer for maintaining at least one radio link control bearer during handover for releasing and adding at least one data radio bearer; A component for maintaining the pre-configured mapping between the at least one logical channel identifier and the at least one identifier of the at least one data radio bearer based on the indication during the handover when releasing and adding the at least one data radio bearer; as well as A component for applying the maintained mapping to route data packets after the switch.

12. A method comprising: Determine whether the target cell configuration of the target cell for the handover of the user equipment corresponds to the source cell configuration of the source cell for the handover of the user equipment; Based on the determination that the target cell configuration does not correspond to the source cell configuration, it is determined that at least one data radio bearer needs to be added for the handover release of the user equipment. as well as Perform at least one of the following: The distributed unit controlling the radio access network node of the target cell transmits an instruction to indicate the release and addition of at least one data radio bearer for the handover of the user equipment; or The radio access network node controlling the source cell transmits an instruction to instruct the user equipment to maintain a pre-configured mapping between at least one logical channel identifier of at least one radio link control bearer and at least one identifier of at least one data radio bearer when releasing and adding the at least one data radio bearer during the handover.

13. A method comprising: Receive instructions from the central unit of the radio access network node regarding the handover release and addition of at least one data radio bearer for user equipment; Identify at least one radio link control bearer associated with the at least one data radio bearer; Based on the instructions, prepare a cell group configuration for the handover release of the user equipment and the addition of the at least one radio link control bearer associated with the at least one data radio bearer; as well as The cell group configuration is transmitted to the central unit, wherein the cell group configuration indicates at least one radio link control bearer to be released and added.

14. A method comprising: Receive an instruction from a radio access network node, the instruction indicating a pre-configured mapping between at least one logical channel identifier and at least one identifier of at least one data radio bearer for releasing and adding the at least one data radio bearer during handover; During the handover, when releasing and adding the at least one data radio bearer, the pre-configured mapping between the at least one logical channel identifier and the at least one identifier of the at least one data radio bearer is maintained based on the indication; as well as The maintained mapping is applied after the switch to route data packets.

15. A non-transitory computer-readable medium comprising program instructions that, when executed by a device, cause the device to perform at least the following operations: Determine whether the target cell configuration of the target cell for the handover of the user equipment corresponds to the source cell configuration of the source cell for the handover of the user equipment; Based on the determination that the target cell configuration does not correspond to the source cell configuration, it is determined that at least one data radio bearer needs to be added for the handover release of the user equipment. as well as Perform at least one of the following: The distributed unit controlling the radio access network node of the target cell transmits an instruction to indicate the release and addition of at least one data radio bearer for the handover of the user equipment; or The radio access network node controlling the source cell transmits an instruction to instruct the user equipment to maintain a pre-configured mapping between at least one logical channel identifier of at least one radio link control bearer and at least one identifier of at least one data radio bearer when releasing and adding the at least one data radio bearer during the handover.

16. A non-transitory computer-readable medium comprising program instructions that, when executed by a device, cause the device to perform at least the following operations: Receive instructions from the central unit of the radio access network node regarding the handover release and addition of at least one data radio bearer for user equipment; Identify at least one radio link control bearer associated with the at least one data radio bearer; Based on the instructions, prepare a cell group configuration for the handover release of the user equipment and the addition of the at least one radio link control bearer associated with the at least one data radio bearer; as well as The cell group configuration is transmitted to the central unit, wherein the cell group configuration indicates at least one radio link control bearer to be released and added.

17. A non-transitory computer-readable medium comprising program instructions that, when executed by a device, cause the device to perform at least the following operations: Receive an instruction from a radio access network node, the instruction indicating a pre-configured mapping between at least one logical channel identifier and at least one identifier of at least one data radio bearer for releasing and adding the at least one data radio bearer during handover; During the handover, when releasing and adding the at least one data radio bearer, the pre-configured mapping between the at least one logical channel identifier and the at least one identifier of the at least one data radio bearer is maintained based on the indication; as well as The maintained mapping is applied after the switch to route data packets.

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