Low layer mobility using slip information

Abstract

Various example embodiments relate to handover in a distributed base station fabric. A network node device central unit may receive, from a target network node device distributed unit, slice information for at least one candidate target cell hosted by the target network node device distributed unit; and transmitting, to the serving network node device distributed unit, handover information to be used by the serving network node device distributed unit to trigger a handover towards one of the at least one candidate target cell. The handover information may be based on slice information for at least one candidate target cell hosted by the distributed unit of the target network node device.

Description

Technical Field

[0001] Various example embodiments relate generally to the field of wireless communications.Some example embodiments relate to handover in a distributed base station architecture. Background Art

[0002] In cellular communication networks, the Radio Access Network (RAN) structure may be segmented into Centralized Units (CU) and Distributed Units (DU) of access network nodes, allowing for both performance and cost benefits. Summary of the invention

[0003] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0004] Example embodiments may improve handover in a distributed base station structure. More specifically, at least some of these example embodiments may improve inter-cell mobility or low-layer mobility centric to layer 1 (L1) or layer 2 (L2) in a distributed base station structure.

[0005] This and other advantages may be achieved by the features of the independent claims.Further exemplary embodiments are provided in the dependent claims, the description and the drawings.

[0006] According to a first aspect, a network node device central unit may include: at least one processor; and at least one memory including computer program code; the at least one memory and the computer program code are configured to, together with the at least one processor, enable the network node device central unit to perform operations, the operations including: receiving slice information for at least one candidate target cell hosted by the target network node device distributed unit from a target network node device distributed unit; and sending switching information to a serving network node device distributed unit to be used by the serving network node device distributed unit to trigger switching toward one of the at least one candidate target cells, the switching information being based on the slice information for at least one candidate target cell hosted by the target network node device distributed unit.

[0007] According to an example embodiment of the first aspect, the handover information includes slice information for at least one candidate target cell hosted by a target network node device distributed unit.

[0008] According to an example embodiment of the first aspect, the operations further include: determining priority information related to the priority of triggering a switch to at least a first candidate target cell among at least one candidate target cell, the priority being determined based on slice information of the at least one candidate target cell; and wherein the switching information includes the priority information.

[0009] According to an example embodiment of the first aspect, the operations further include: adjusting at least one radio switching trigger condition for at least one candidate target cell based on slice information for at least one candidate target cell; and wherein the switching information includes the adjusted radio switching trigger condition for at least one candidate target cell, and the adjusted radio switching trigger condition will be associated by the serving network node device distributed unit with at least one layer 1L1 measurement for making a switching decision.

[0010] According to an example embodiment of the first aspect, at least one radio switching trigger condition includes at least one of the following: an offset, a threshold, or a trigger time, and wherein, based on slice information of at least one candidate target cell, adjusting at least one radio switching trigger condition for at least one candidate target cell includes: adjusting the offset of at least one candidate target cell; adjusting the threshold of at least one candidate target cell; or adjusting the trigger time of at least one candidate target cell.

[0011] According to an example embodiment of the first aspect, at least one candidate target cell includes a first candidate target cell and a second candidate target cell, and the operations further include: sending a first switching trigger condition for the first candidate target cell and a second switching trigger condition for the second candidate target cell to a distributed unit of a service network node device, the first switching trigger condition and the second switching trigger condition being associated by the distributed unit of the service network node device with at least one L1 measurement received from a user equipment; receiving an indication from the distributed unit of the service network node device that the first candidate target cell verifies the first switching condition and the second candidate target cell verifies the second switching condition; and selecting the first candidate target cell for switching based on slice information for the first candidate target cell and the second candidate target cell; and wherein sending the switching information to the distributed unit of the service network node device includes: sending an instruction to the distributed unit of the service network node device for triggering switching to the first candidate target cell.

[0012] According to an example embodiment of the first aspect, sending switching information to a serving network node device distributed unit includes: sending slice information for at least one candidate target cell and a timer indicating validity of the slice information to the serving network node device distributed unit.

[0013] According to an example embodiment of the first aspect, slice information for at least one candidate target cell includes an indication of at least one network slice permitted, rejected or remapped by the candidate target cell.

[0014] According to an example embodiment of the first aspect, slice information for at least one candidate target cell includes a capability of the candidate target cell to perform network slice remapping.

[0015] According to a second aspect, a method may include: receiving slice information for at least one candidate target cell hosted by the target network node device distributed unit from a target network node device distributed unit; and sending switching information to a serving network node device distributed unit to be used by the serving network node device distributed unit to trigger switching toward one of the at least one candidate target cells, the switching information being based on the slice information for at least one candidate target cell hosted by the target network node device distributed unit.

[0016] According to a third aspect, a computer program may include instructions for causing a network node device central unit to perform at least the following operations: receiving slice information for at least one candidate target cell hosted by the target network node device distributed unit from a target network node device distributed unit; and sending switching information to a serving network node device distributed unit to be used by the serving network node device distributed unit to trigger switching toward one of the at least one candidate target cells, the switching information being based on the slice information for at least one candidate target cell hosted by the target network node device distributed unit.

[0017] According to a fourth aspect, a network node device central unit may include: a component for receiving slice information for at least one candidate target cell hosted by the target network node device distributed unit from a target network node device distributed unit; and a component for sending switching information to a serving network node device distributed unit to be used by the serving network node device distributed unit to trigger switching toward one of the at least one candidate target cells, wherein the switching information is based on slice information for at least one candidate target cell hosted by the target network node device distributed unit.

[0018] According to a fifth aspect, a service network node device distributed unit comprises: at least one processor; and at least one memory comprising computer program code; the at least one memory and the computer program code are configured to, together with the at least one processor, enable the service network node device distributed unit to perform operations, the operations comprising: receiving switching information from a network node device central unit, the switching information being based on slice information for at least one candidate target cell hosted by a target network node device distributed unit; and using the switching information to trigger switching toward one of the at least one candidate target cells.

[0019] According to an example embodiment of the fifth aspect, the handover information includes slice information for at least one candidate target cell hosted by a target network node device distributed unit.

[0020] According to an example embodiment of the fifth aspect, the switching information includes priority information related to the priority of triggering switching to at least a first candidate target cell among at least one candidate target cell, and the priority is used based on slice information of the at least one candidate target cell.

[0021] According to an example embodiment of the fifth aspect, the switching information includes at least one adjusted radio switching trigger condition, which is adjusted based on slice information of at least one candidate target cell; and wherein using the switching information includes: associating the at least one adjusted radio switching trigger condition with at least one L1 measurement received from a user equipment; and determining whether the at least one adjusted radio switching trigger condition is satisfied based on the at least one L1 measurement received.

[0022] According to an example embodiment of the fifth aspect, at least one adjusted radio switching trigger condition includes at least one of: an adjusted offset, an adjusted threshold, or adjusted trigger time information.

[0023] According to an example embodiment of the fifth aspect, at least one candidate target cell includes a first candidate target cell and a second candidate target cell, and the operations further include: receiving a switching trigger condition for the first candidate target cell and a switching trigger condition for the second candidate target cell from a central unit of a network node device; associating the first switching trigger condition and the second switching trigger condition with at least one L1 measurement received from a user equipment; determining that the first candidate target cell verifies the first switching condition and the second candidate target cell verifies the second switching condition for the second candidate target cell; sending an indication to the central unit of the network node device that the first candidate target cell verifies the first switching condition and the second candidate target cell verifies the second switching condition for the second candidate target cell; and wherein receiving switching information from the central unit of the network node device includes: receiving an instruction from the central unit of the network node device for triggering a switch to the first candidate target cell, wherein the first candidate target cell is selected based on slice information.

[0024] According to an example embodiment of the fifth aspect, slice information for at least one candidate target cell includes an indication of at least one network slice permitted, rejected or remapped by the candidate target cell.

[0025] According to an example embodiment of the fifth aspect, slice information for at least one candidate target cell includes the ability of the candidate target cell to perform network slice remapping.

[0026] According to a sixth aspect, a method may include: receiving switching information from a network node device central unit, the switching information being based on slice information for at least one candidate target cell hosted by a target network node device distributed unit; and using the switching information to trigger switching toward one of the at least one candidate target cells.

[0027] According to the seventh aspect, a computer program may include instructions for causing a serving network node device distributed unit to perform at least the following operations: receiving switching information from a network node device central unit, the switching information being based on slice information for at least one candidate target cell hosted by a target network node device distributed unit; and using the switching information to trigger a switch toward one of the at least one candidate target cells.

[0028] According to the eighth aspect, a service network node device distributed unit may include: a component for receiving switching information from a network node device central unit, wherein the switching information is based on slice information for at least one candidate target cell hosted by the target network node device distributed unit; and a component for using the switching information to trigger switching toward one of the at least one candidate target cells.

[0029] Any exemplary embodiment may be combined with one or more other exemplary embodiments.Many of the accompanying features will be more readily appreciated as they are better understood by reference to the following detailed description considered in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings, which are included to provide a further understanding of example embodiments and constitute a part of this specification, illustrate example embodiments and together with the description assist in understanding these example embodiments. In the drawings:

[0031] Figure 1A An example embodiment of a communication network is shown;

[0032] Figure 1B An example embodiment showing the format of S-NSSAI;

[0033] Figure 2 illustrates an example serving network node device in which various embodiments of the present disclosure may be implemented;

[0034] Figure 3 illustrates an example target network node device in which various embodiments of the present disclosure may be implemented;

[0035] Figure 4A An example embodiment of the subject matter described herein is shown, which shows a network node device central unit;

[0036] Figure 4B An example embodiment of the subject matter described herein is shown, which illustrates a serving network node device distributed unit; and

[0037] Figure 5A An example embodiment of the subject matter described herein is shown, which illustrates a method that may be implemented at a network node device central unit;

[0038] Figure 5B An example embodiment of the subject matter described herein is shown, which illustrates a method that may be implemented at a serving network node device distributed unit;

[0039] Figure 6 An example signaling diagram illustrating a method according to an example embodiment;

[0040] Figure 7 An example signaling diagram illustrating a method according to an example embodiment;

[0041] Figure 8 An example signaling diagram illustrating a method according to an example embodiment;

[0042] Fig. 9 An example signaling diagram illustrating a method according to an example embodiment;

[0043] Fig.10 An example signaling diagram illustrating a method according to an example embodiment.

[0044] In the drawings, like reference numerals are used to designate like parts. DETAILED DESCRIPTION

[0045] Reference will now be made in detail to example embodiments, examples of which are shown in the accompanying drawings. The detailed description provided below in conjunction with the drawings is intended as a description of the proposed examples and is not intended to represent the only form in which the proposed examples can be constructed or utilized. The description sets forth the functions of the examples and the sequence of steps for constructing and operating the examples. However, the same or equivalent functions and sequences may be implemented by different examples.

[0046] Figure 1A An example system 100 is shown in which various embodiments of the present disclosure may be implemented. The system 100 may include a network 110, for example, a fifth generation (5G) new radio (NR) network. An example representation of the system 100 is shown, which shows a user device 120, a serving network node device 200, and a target network node device 300. In at least some embodiments, the 5G NR network 110 may include one or more massive machine-to-machine (M2M) networks, massive machine type communication (mMTC) networks, Internet of Things (IoT) networks, Industrial Internet of Things (IIoT) networks, enhanced mobile broadband (eMBB) networks, ultra-reliable low latency communication (URLLC) networks, etc. In other words, the 5G NR network 110 may be configured to serve different service types and / or use cases, and may be logically viewed as including one or more networks.

[0047] The user equipment 120 may include, for example, a mobile phone, a smart phone, a tablet computer, a smart watch, or any handheld or portable device. The user equipment 120 may also be referred to as a user equipment (UE). The network node devices 200, 300 may include a base station. The base station may include, for example, a fifth generation base station (gNB) or any such device suitable for providing an air interface for a user equipment to connect to a wireless network via wireless transmission.

[0048] The service network node device 200 is logically divided into a centralized unit and a distributed unit. More specifically, Figure 2As shown in , the serving network node device 200 may be logically partitioned into a gNB central unit (gNB-CU) and one or more gNB distributed units (gNB-DU) 230. In addition, the gNB-CU may be logically partitioned into a control plane (CP) portion or entity (gNB-CU-CP) 210 and one or more user plane (UP) portions or entities (gNB-CU-UP) 220. Thus, the 5G serving gNB 200 may provide 5G user plane and control plane protocol terminations toward the user equipment 120. The UP may be used to carry user services (such as voice) and Internet services, while the CP may be used to carry control messages, such as for signaling in the system 100.

[0049] The gNB-CU 210, 220 is a logical node that can host higher layer protocols such as Radio Resource Control (RRC), Service Data Adaptation Protocol (SDAP), and Packet Data Convergence Protocol (PDCP). The gNB-DU 230 is a logical node that can host, for example, Radio Link Control (RLC), Medium Access Control (MAC), and higher physical (PHY) layers.

[0050] The E1 interface may be used, for example, to provide signaling information exchange between the gNB-CU-CP 210 and the gNB-CU-UP 220. The F1-C interface may be used, for example, to provide control plane interconnection between the gNB-CU-CP 210 and the gNB-DU 230, and the F1-U interface may be used, for example, to provide user plane interconnection between the gNB-CU-UP 220 and the gNB-DU 230.

[0051] The target network node device 300 is also logically divided into a centralized unit and a distributed unit. More specifically, Figure 3 As shown in , the target network node device 300 can be logically partitioned into a gNB central unit (gNB-CU) and one or more gNB distributed units (gNB-DU) 330. In addition, the gNB-CU can be logically partitioned into a control plane (CP) part or entity (gNB-CU-CP) 310 and one or more user plane (UP) parts or entities (gNB-CU-UP) 320. Therefore, the 5G target gNB 300 can also provide 5G user plane and control plane protocol termination towards the user equipment 120. The UP can be used to carry user services (such as voice) and Internet services, while the CP can be used to carry control messages, such as those used for signaling in the system 100.

[0052] The gNB-CU 310, 320 is a logical node that can host higher layer protocols such as Radio Resource Control (RRC), Service Data Adaptation Protocol (SDAP), and Packet Data Convergence Protocol (PDCP). The gNB-DU 330 is a logical node that can host, for example, the Radio Link Control (RLC), Medium Access Control (MAC), and Physical (PHY) layers.

[0053] The E1 interface may be used, for example, to provide signaling information exchange between the gNB-CU-CP 310 and the gNB-CU-UP 320. The F1-C interface may be used, for example, to provide control plane interconnection between the gNB-CU-CP 310 and the gNB-DU 330, and the F1-U interface may be used, for example, to provide user plane interconnection between the gNB-CU-UP 320 and the gNB-DU 330.

[0054] Network slices can be used to support different services that use the same underlying mobile network infrastructure. Network slices may differ in their service requirements, such as ultra-reliable low-latency communications (URLLC) and enhanced mobile broadband (eMBB), or in the tenants that provide these services.

[0055] Network slicing can enable the definition of multiple virtual networks on the same underlying mobile network infrastructure. A network slice can represent an independent virtualized instance defined by the allocation of a subset of available network resources. A network slice can be customized to meet the specific requirements of a set of applications and services. A network slice may include a set of rules that define a separate subset of available virtual resources (e.g., computing, network, storage) and a set of rules for identifying the services that will run on these resources. A network slice may include a set of virtual resources and service flows associated therewith. In particular, a network slice may include dedicated radio, transport, and core resources, including dedicated user plane functions at the edge.

[0056] A Protocol Data Unit (PDU) Session may provide an end-to-end user plane connection between a UE and a specific Data Network (DN) through a User Plane Function (UPF). A PDU Session may belong to one and only one specific Network Slice Instance per serving Public Land Mobile Network (PLMN). Different Network Slice Instances do not share PDU Sessions, although different Network Slice Instances may have slice-specific PDU Sessions using the same Data Network Name (DNN).

[0057] A network slice can be uniquely identified via S-NSSAI (Single Network Slice Selection Assistance Information). Figure 1BAn example format of S-NSSAI is shown. A UE may be simultaneously connected to and served by multiple (e.g., up to eight) network slices corresponding to corresponding S-NSSAIs. In addition, each cell may support multiple (e.g., up to 1024) S-NSSAIs. The S-NSSAI may include both a slice service type (SST) and a slice distinguisher (SD) field, having, for example, a total length of 32 bits, or may include only a portion of the SST field, in which case the length of the S-NSSAI may be, for example, only 8 bits.

[0058] The SST field can have standardized and non-standardized values. Values ​​0 to 127 can belong to the standardized SST range. For example, an SST value of 1 can indicate that the network slice is suitable for handling 5G eMBB, an SST value of 2 is suitable for handling URLLC, etc. SD is defined only by the operator.

[0059] From the UE's perspective, the states of a network slice can be listed as follows:

[0060] - Allowed NSSAI: NSSAI provided by the PLMN, for example during the registration procedure, indicating the S-NSSAI values ​​that the UE can use in the serving network node for the current registration area.

[0061] - Configured NSSAI: NSSAI provided in the UE, applicable to one or more PLMNs.

[0062] - Requested NSSAI: NSSAI provided by the UE to the serving PLMN during registration.

[0063] - Pending NSSAI: NSSAI provided by the serving PLMN during the registration process, indicating the S-NSSAI pending for the network slice specific authentication and authorization process.

[0064] - Subscribed S-NSSAI: S-NSSAI based on subscriber information, to which the UE subscribes for use in the PLMN.

[0065] The requested NSSAI can be one of the following:

[0066] - the default configured NSSAI, i.e. if the UE has no configured NSSIA and no allowed NSSAI for the PLMN; - the configured NSSAI or a subset thereof (as described below), e.g. if the UE has no allowed NSSAI for the access type of the PLMN;

[0067] - the allowed NSSAIs or a subset thereof for the access type over which the requested NSSAI is sent; or - the allowed NSSAIs or a subset thereof for the access type over which the requested NSSAI is sent, plus one or more S-NSSAIs from the configured NSSAIs that are not already in the allowed NSSAIs for the access type.

[0068] In the distributed gNB structure, in contrast to the high-layer mobility procedures (where handover between two cells is decided by the RRC layer), low-layer mobility (e.g., L1 / 2 inter-cell mobility) can be performed by the MAC layer terminated in the DU.

[0069] In low-layer mobility, a serving distributed unit (serving DU) only knows its own slice information, but not the slice information of cells hosted by a target distributed unit (target DU). Similarly, a target DU only knows its own slice information, but not the slice information of cells hosted by other target DUs. If the serving DU only knows the L1 radio beam measurements received from the UE, the serving DU may not be able to consider the slice support information and / or slice-specific PDU session remapping to make a handover decision.

[0070] Therefore, the problem may be that the serving DU of the serving cell is unaware of the slice information of the target cell. This limits the operation of the serving DU in low layer mobility (LLM). In particular, the serving DU may not trigger an LLM handover that is ideal in terms of slice support. The serving DU may trigger an LLM handover to a target cell that does not support at least one of the allowed, configured slices of the UE. In addition, the serving DU may trigger a handover to a cell that does not support one of the active PDU sessions for a slice.

[0071] In the following, various example embodiments are discussed. At least some of these example embodiments can improve handover in a distributed base station structure. More specifically, at least some of these example embodiments can improve low-layer mobility (e.g., inter-cell mobility centered around L1 / L2) in a distributed base station structure.

[0072] In this document, the terms "layer 1 (L1)", "layer 2 (L2)", and "layer 3 (L3)" refer to corresponding layers of the protocol stack of the 5G NR network 110. Thus, L1 may include, for example, a physical layer. L2 may include, for example, a radio link control (RLC) sublayer, a medium access control (MAC) sublayer, a service data adaptation protocol (SDAP) sublayer, and / or a packet data convergence protocol (PDCP) sublayer. L3 may include, for example, a radio resource control (RRC) layer.

[0073] The example embodiments described herein may be particularly applicable to inter-frequency handover scenarios, where at least one target cell may be used to trigger low-layer inter-cell mobility handover.

[0074] Example embodiments described herein may enable a serving DU to make better decisions for triggering low-layer inter-cell mobility by considering data radio bearers (DRBs) mapped onto permitted PDU sessions in candidate target cells.

[0075] The serving centralized unit (serving CU) controlling the serving cell can be informed by the target gNB controlling the target cell about PDU session grant or rejection, each PDU session is associated with a network slice. Slice information of neighboring gNBs can be exchanged via the Xn Application Protocol (XnAP) procedure per tracking area. Using this information, the serving CU and / or serving DU can make handover decisions based not only on radio measurements, but also on slice support in the target cell.

[0076] Figure 4A is a block diagram of a network node device central unit 410 according to an example embodiment.

[0077] The network node device central unit 410 includes one or more processors 412 and one or more memories 414 including computer program code. The network node device central unit 410 may also include other elements, such as a transceiver 416 and Figure 4A Other elements not shown.

[0078] Although the network node device central unit 410 is shown as including only one processor 412, the network node device central unit 410 may include more processors. In an embodiment, the memory 414 is capable of storing instructions, such as an operating system and / or various applications. In addition, the memory 414 may include a storage device that can be used to store at least some of the information and data used in the disclosed embodiments, for example.

[0079] In addition, the processor 412 is capable of executing the stored instructions. In an embodiment, the processor 412 may be embodied as a multi-core processor, a single-core processor, or a combination of one or more multi-core processors and one or more single-core processors. For example, the processor 412 may be embodied as one or more of various processing devices, such as a coprocessor, a microprocessor, a controller, a digital signal processor (DSP), a processing circuit with or without an attached DSP, or various other processing devices including integrated circuits, such as, for example, an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), a microcontroller unit (MCU), a hardware accelerator, a dedicated computer chip, etc. In an embodiment, the processor 412 may be configured to perform hard-coded functions. In an embodiment, the processor 412 is embodied as an executor of software instructions, wherein these instructions may specifically configure the processor 412 to perform the algorithms and / or operations described herein when executing these instructions.

[0080] The memory 414 may be embodied as one or more volatile memory devices, one or more non-volatile memory devices, and / or a combination of one or more volatile memory devices and non-volatile memory devices. For example, the memory 414 may be embodied as a semiconductor memory (such as a mask ROM, a PROM (programmable ROM), an EPROM (erasable PROM), a flash ROM, a RAM (random access memory), etc.).

[0081] In at least some embodiments, the network node device central unit 410 may include Figure 2 gNB-CU-CP 210.

[0082] Figure 5A An example embodiment of the method is shown. Some of the operations described may not be present in all example embodiments, and example embodiments may also include additional features / operations described elsewhere in this specification. An apparatus such as a network node device central unit 410 may be configured to perform Figure 5A The functions and operations of the methods.

[0083] At operation 501, a serving CU (e.g., a network node device central unit 410) receives slice information for at least one candidate target cell hosted by a target DU (e.g., a target gNB-DU 330) from a target gNB (e.g., a target gNB 300). In particular, the slice information may be received during handover preparation. Slice information of neighboring gNBs may be exchanged via an Xn Application Protocol (XnAP) procedure per tracking area. Using the slice information, a handover decision may be made based on slice support in the target node in addition to radio measurements.

[0084] The slice information may identify at least one network slice permitted, rejected, or remapped by the candidate target cell. The slice information may identify a DRB associated with a PDU session associated with the identified network slice.

[0085] In particular, the UE may have a PDU session with allowed slices. The UE may not have a PDU session with allowed slices, for example if the UE has not established a PDU session for that slice. The UE may also have configured slices, for example if the UE has not activated that slice because the service was not active at the time of preparation. It may be assumed that the target CU supports allowed slices with active PDU sessions, as these are the slices that require radio support. However, the UE may still prefer to go to a cell that also supports slices without active PDU sessions or configured slices, so that the UE can also use these slices.

[0086] The slice information may also include slice remapping information. Some network slices may not be supported in the candidate target cell. The slice information may indicate whether the target cell supports slice remapping. If slice remapping is supported, the slice information may further indicate whether the network slice associated with a certain PDU session will be remapped to another slice.

[0087] At operation 502, the serving CU (e.g., the network node device central unit 410) sends handover information to the serving DU (e.g., the gNB-DU 230). The serving DU uses the handover information to trigger handover. The handover information is determined based on the slice information. Figures 6 to 10 Example embodiments of determining switching information based on slice information are described.

[0088] Figure 4B is a block diagram of a serving network node device distribution unit 430 according to an example embodiment.

[0089] The service network node device distributed unit 430 includes one or more processors 432 and one or more memories 434 including computer program code. The service network node device distributed unit 430 may also include other elements, such as a transceiver 436 and Figure 4B Other elements not shown.

[0090] Although the service network node device distributed unit 430 is shown as including only one processor 432, the service network node device distributed unit 430 may include more processors. In an embodiment, the memory 434 can store instructions, such as an operating system and / or various applications. In addition, the memory 434 may include a storage device that can be used to store, for example, at least some of the information and data used in the disclosed embodiments.

[0091] In addition, the processor 432 is capable of executing the stored instructions. In an embodiment, the processor 432 may be embodied as a multi-core processor, a single-core processor, or a combination of one or more multi-core processors and one or more single-core processors. For example, the processor 432 may be embodied as one or more of various processing devices, such as a coprocessor, a microprocessor, a controller, a digital signal processor (DSP), a processing circuit with or without an attached DSP, or various other processing devices including integrated circuits, such as, for example, an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), a microcontroller unit (MCU), a hardware accelerator, a dedicated computer chip, etc. In an embodiment, the processor 432 may be configured to perform hard-coded functions. In an embodiment, the processor 432 is embodied as an executor of software instructions, wherein these instructions may specifically configure the processor 432 to perform the algorithms and / or operations described herein when executing these instructions.

[0092] The memory 434 may be embodied as one or more volatile memory devices, one or more non-volatile memory devices, and / or a combination of one or more volatile memory devices and non-volatile memory devices. For example, the memory 434 may be embodied as a semiconductor memory (such as a mask ROM, a PROM (programmable ROM), an EPROM (erasable PROM), a flash ROM, a RAM (random access memory), etc.).

[0093] In at least some embodiments, the service network node device distribution unit 430 may include Figure 2 gNB-DU230.

[0094] Figure 5B An example embodiment of the method is shown. Some of the operations described may not be present in all example embodiments, and example embodiments may also include additional features / operations described elsewhere in this specification. An apparatus such as the service network node device distributed unit 430 may be configured to perform Figure 5B The functions and operations of the methods.

[0095] At operation 511, the serving DU (e.g., the serving network node device distributed unit 430) receives handover information from the serving CU (e.g., the network node device central unit 410). The handover information may be based on slice information for at least one candidate target cell hosted by the target DU (e.g., the target gNB-DU 330).

[0096] At operation 512, the serving DU (eg, the serving network node device distributed unit 430) uses the handover information to trigger a handover to one of the at least one candidate target cells. Figures 6 to 10Example embodiments are described that use handover information to trigger handover.

[0097] Figure 6 is an example signaling diagram 600 of a method according to an example embodiment. Some of the described operations may not be present in all example embodiments, and example embodiments may also include additional features / operations described elsewhere in this specification.

[0098] Can be Figure 4A The network node device central unit 410 and Figure 4B The service network node device distributed unit 430 performs at least part of the method of the schematic diagram 600. Further features of the method of the schematic diagram 600 are directly derived from Figure 4B The functions and parameters of the network node device central unit (CU) 410, the serving network node device distributed unit (serving DU) 430 and the target network node device distributed unit (target DU) 330 are described in detail and therefore are not repeated here. The method of the schematic diagram 600 may be performed by a computer program.

[0099] Prior to operation 601, CU 410 may receive at least one measurement report from UE 120. The measurement report may include L3 measurements. The measurement report may be used to identify at least one candidate target cell. In particular, the measurement report may be used to prove that the preparation conditions for the candidate target cell are verified. The candidate target cell may be hosted by the same target DU or different target DUs.

[0100] At operation 601, CU 410 may receive slice information for at least one of the candidate target cells from a target gNB (e.g., from target DU 330). The slice information may be received from the target gNB via an XnAP procedure. The slice information may be received with LLM preparation. The slice information update may also be included in a resource status update.

[0101] At operation 602, CU 410 may send handover information to serving DU 430. The handover information may be sent with LLM preparation. CU 410 may send LLM preparation in a UE context modification request. The UE context modification request message may include an RRC message and indicate the LLM configuration for one or more target cells. The handover information may also be sent to the serving DU in a gNB CU configuration update message.

[0102] In some embodiments, particularly with respect to Figure 7In some example embodiments described, the handover information may include slice information of at least one of the candidate target cells. In particular, the handover information may indicate at least one PDU session associated with at least one network slice permitted, rejected or remapped by the candidate target cell.

[0103] In some embodiments, particularly with respect to Figure 7 In some example embodiments described, the handover information may include priority information for the handover. The priority information may be used to trigger a handover to one or more higher priority cells before a handover to one or more lower priority cells. For example, the handover information may indicate that one of the candidate target cells should be prioritized for handover. The handover information may indicate a priority of one or more of the plurality of candidate target cells. The handover information may also indicate an absolute priority of one or more candidate targets, indicating that these candidate target cells should always be selected for handover. The priority for handover may be determined based on the slice information.

[0104] In some embodiments, particularly with respect to Figure 8 In some of the described example embodiments, the handover information may include an adjusted handover trigger condition.

[0105] In some embodiments, particularly with respect to Fig. 9 In some of the described example embodiments, the handover information may include a selected candidate target cell for handover.

[0106] In some embodiments, particularly with respect to Fig.10 In some of the described example embodiments, the switching information may include slice information and a timer indicating the validity of the slice information.

[0107] At operation 603, UE 120 may send at least one L1 measurement report to serving DU 430. UE 120 may send the L1 measurement report periodically or in an event-based manner. The L1 measurement report may include measurements of beams of both the serving cell and the non-serving candidate target cell. The measurement quantity used for L1 measurement may be, for example, reference signal received power (RSRP) and reference signal received quality (RSRQ) or L1-SINR.

[0108] At operation 604, the serving DU 430 may use the handover information. In particular, the serving DU 430 may use the handover information to make a handover decision. In particular, the serving DU 430 may evaluate a handover trigger condition. The handover trigger condition may take into account L1 measurements as well as the handover information.

[0109] At operation 605, if the handover triggering condition is satisfied, the serving DU 430 may initiate the handover. The serving DU 430 may send a handover instruction to the UE 120, for example, via a MAC Control Element (MAC CE) message.

[0110] Figure 7 is an example signaling diagram 700 of a method according to an example embodiment. Some of the described operations may not be present in all example embodiments, and example embodiments may also include additional features / operations described elsewhere in this specification.

[0111] Can be Figure 4A The network node device central unit 410 and Figure 4B The service network node device distributed unit 430 performs at least part of the method of the schematic diagram 700. Further features of the method of the schematic diagram 700 are directly derived from Figure 4B The functions and parameters of the network node device central unit (CU) 410, the serving network node device distributed unit (serving DU) 430 and the target network node device distributed unit (target DU) 330 are described in detail and are therefore not repeated here. The method of the schematic diagram 700 may be performed by a computer program.

[0112] Prior to operation 701, CU 410 may receive at least one measurement report from UE 120. The measurement report may include L3 measurements. The measurement report may be used to identify at least one candidate target cell. In particular, the measurement report may be used to prove that the preparation conditions for the candidate target cell are verified. The candidate target cell may be hosted by the same target DU or different target DUs.

[0113] At operation 701, the CU 410 may receive slice information for at least one of the candidate target cells from the target DU 330. The slice information may be received from the target gNB via an XnAP procedure. The slice information may be received, for example, via an F1 interface together with LLM preparation.

[0114] At operation 702, CU 410 may send handover information to serving DU 430. The handover information may be sent together with LLM preparation. CU 410 may send LLM preparation in a UE context modification request. The UE context modification request message may include an RRC message and indicate at least one LLM configuration for one or more target cells.

[0115] In some example embodiments, the handover information may include slice information of at least one of the candidate target cells. In particular, the handover information may include at least one PDU session associated with at least one network slice permitted, rejected, or remapped by the candidate target cell.

[0116] In some example embodiments, the handover information may include a priority of at least one of the candidate target cells for handover. For example, the handover information may indicate that one of the candidate target cells should be prioritized for handover. The priority for handover may be determined based on the slice information. In particular, the priority for handover may be determined based on the number of PDU sessions for the UE permitted by the candidate target cell. For example, the handover information may indicate that a first candidate target cell has a higher priority than a second candidate target cell because it has permitted more PDU sessions for the UE. For example, the priority for handover may be a soft value from 1 to 10, where 1 indicates the highest priority and 10 indicates the lowest priority.

[0117] At operation 703 , the serving DU 430 may confirm the reception of the LLM preparation through another message (eg, a “UE Context Modification Response” message sent to the CU 410 ).

[0118] At operation 704, UE 120 may be configured with an LLM configuration for a candidate target cell, for example, through RRC Reconfiguration.

[0119] At operation 705 , the UE 120 may confirm the receipt of the LLM configuration through another message (eg, an “RRCReconfiguration Complete” message sent to the serving DU 430 ).

[0120] At operation 706, the serving DU 330 may send an uplink (UL) RRC message transfer message to the CU 410 to convey the received RRCReconfigurationComplete message.

[0121] At operation 707, UE 120 may send at least one L1 measurement report to serving DU 430. UE 120 may send the L1 measurement report periodically or in an event-based manner. The L1 measurement report may include measurements of beams of both the serving cell and the non-serving cell. The measurement quantity used for the L1 measurement may be, for example, reference signal received power (RSRP) and reference signal received quality (RSRQ) or L1-SINR.

[0122] At operation 708, the serving DU 430 may make a handover decision based on the handover information. In particular, the serving DU 430 may evaluate a handover trigger condition. If the handover trigger condition is met, a handover may be initiated by the serving DU 430. The handover trigger condition may take into account the L1 measurement value as well as the handover information.

[0123] The handover triggering condition may include a radio handover triggering condition associated with the L1 measurement. For example, the radio handover triggering condition may include offset information, threshold information, and / or triggering time information, which the serving DU 430 may associate and apply to the L1 measurement received from the UE 120 and / or the L2 measurement generated by the serving DU 430 based on the L1 measurement received from the UE 120. For example, the L1 or L2 measurement may include RSRP or RSRQ.

[0124] In other words, the radio conditions may include an offset / threshold and / or a trigger time, which is used to compare the measurements of the serving cell with the measurements of the candidate target cell.

[0125] The switching triggering condition may further include at least one slice-related condition based on the switching information.

[0126] In some embodiments, the slice-related handover triggering condition may be determined based on the slice information. For example, the slice-related handover triggering condition may be based on a list of PDU sessions associated with each network slice permitted, rejected, or remapped by the prepared target cell. In particular, the service DU 430 may select a candidate target cell based on the number of PDU sessions of the UE permitted by the candidate target cell. For example, the service DU 430 may select a candidate target cell based on the highest number of PDU sessions of the UE permitted by the candidate target cell.

[0127] In some embodiments, the slice-related handover triggering condition may be based on the priority of the candidate target cell indicated in the handover information.

[0128] Figure 8 is an example signaling diagram 800 of a method according to an example embodiment. Some of the described operations may not be present in all example embodiments, and example embodiments may also include additional features / operations described elsewhere in this specification.

[0129] Can be Figure 4A The network node device central unit 410 and Figure 4B The service network node device distributed unit 430 performs at least part of the method of the schematic diagram 800. Further features of the method of the schematic diagram 800 are directly derived from Figure 4B The functions and parameters of the network node device central unit (CU) 410, the serving network node device distributed unit (serving DU) 430 and the target network node device distributed unit (target DU) 330 are described in detail and therefore are not repeated here. The method of the schematic diagram 800 may be performed by a computer program.

[0130] Prior to operation 801, CU 410 may receive at least one measurement report from UE 120. The measurement report may include L3 measurements. The measurement report may be used to identify at least one candidate target cell. In particular, the measurement report may be used to prove that the preparation conditions for the candidate target cell are verified. The candidate target cell may be hosted by the same target DU or different target DUs.

[0131] At operation 801, CU 410 may send at least one radio switching triggering condition for a target cell to serving DU 430. CU 410 may send the radio switching triggering condition in a UE context modification request. The UE context modification request message may include an RRC message and indicate at least one LLM configuration for one or more target cells.

[0132] The radio switching trigger condition may be associated with the L1 measurement. For example, the radio switching trigger condition may include offset information, threshold information, and / or trigger time information, which the serving DU 430 may associate and apply to the L1 measurement received from the UE 120 and / or the L2 measurement generated by the serving DU 430 based on the L1 measurement received from the UE 120. For example, the L1 or L2 measurement may include RSRP or RSRQ.

[0133] In other words, the radio conditions may include offsets / thresholds and / or trigger times, which are used to compare measurements of the serving cell with measurements of the candidate target cells.

[0134] At operation 802 , the serving DU 430 may confirm the reception of the radio switching triggering condition through another message (eg, a “UE Context Modification Response” message sent to the CU 410 ).

[0135] At operation 803, the UE may be configured with an LLM configuration for a candidate target cell, for example, through RRC Reconfiguration.

[0136] At operation 804 , the UE may confirm the receipt of the LLM configuration of the candidate target cell through another message (eg, a “RRCReconfiguration Complete” message sent to the serving DU 430 ).

[0137] At operation 805, the serving DU 330 may send an uplink (UL) RRC message transmission message to the network node device central unit 410 to transfer the received RRCReconfigurationComplete message.

[0138] At operation 806, the target DU may transmit slice information for at least one of the candidate target cells to the CU 410. The slice information may be transmitted to the CU 410 in a resource status update.

[0139] At operation 807, the CU 410 may adjust the radio switching trigger condition based on the slice information. For example, the triggering time for the first candidate target cell may be adjusted compared to the other candidate target cells. As another example, the threshold for the first candidate target cell may be adjusted compared to the other candidate target cells. As another example, the time-to-trigger for the first candidate target cell may be adjusted compared to the other candidate target cells.

[0140] In particular, CU 410 may identify an overload of a first slice of a first candidate target cell. CU 410 may determine that the overload is related to the UE. For example, if the UE requests the first slice (e.g., during UE context establishment), CU 410 may determine that the overload is related to the UE. If CU 410 determines that the overload of the first candidate target cell is related to the UE, CU 410 may modify the radio switching trigger condition to reduce the priority of the first candidate target cell. Parameters of the switching trigger radio conditions for the first candidate target cell and / or other candidate target cells may be adjusted so that switching is preferentially performed toward other candidate target cells compared to the first candidate target cell. For example, the triggering time for the first candidate target cell may be increased compared to other candidate target cells. As another example, a threshold for the first candidate target cell may be increased compared to other candidate target cells. As another example, a triggering time for the first candidate target cell may be increased compared to other candidate target cells.

[0141] At operation 808, the CU 410 may send the handover information to the serving DU 430. The handover information may include the adjusted radio handover triggering condition sent to the serving DU 430. The CU 410 may send the adjusted radio handover triggering condition in a UE context modification request.

[0142] At operation 809 , the serving DU 430 may confirm the reception of the updated handover triggering condition through another message (eg, a “UE Context Modification Response” message sent to the CU 410 ).

[0143] At operation 810, UE 120 may send an L1 measurement report to serving DU 430. UE 120 may send the L1 measurement report periodically or in an event-based manner. The L1 measurement report may include measurements of beams of both the serving cell and the non-serving cell. The measurement quantity used for L1 measurement may be, for example, reference signal received power (RSRP) and reference signal received quality (RSRQ) or L1-SINR.

[0144] At operation 811, the serving DU 430 may use the handover information to make a handover decision. In particular, the serving DU 430 may apply L1 measurements to evaluate the adjusted radio handover triggering condition.

[0145] At operation 812, if the adjusted radio switching triggering condition is satisfied, the serving DU 430 may initiate the switching. The serving DU 430 may send the switching instruction to the UE 120, for example, via a MAC Control Element (MAC CE) message.

[0146] Fig. 9 is an example signaling diagram 900 of a method according to an example embodiment. Some of the described operations may not be present in all example embodiments, and example embodiments may also include additional features / operations described elsewhere in this specification.

[0147] Can be Figure 4A The network node device central unit 410 and Figure 4B The service network node device distributed unit 430 performs at least part of the method of the schematic diagram 900. Further features of the method of the schematic diagram 900 are directly derived from Figure 4B The functions and parameters of the network node device central unit (CU) 410, the serving network node device distributed unit (serving DU) 430 and the target network node device distributed unit (target DU) 330 are described in detail and are therefore not repeated here. The method of the schematic diagram 900 may be performed by a computer program.

[0148] Prior to operation 901, CU 410 may receive at least one measurement report from UE 120. The measurement report may include L3 measurements. The measurement report may be used to identify at least one candidate target cell. In particular, the measurement report may be used to prove that the preparation conditions for the candidate target cell are verified. The candidate target cell may be hosted by the same target DU or different target DUs.

[0149] At operation 901, CU 410 may send a first handover trigger condition for a first candidate target cell and a second handover trigger condition for a second candidate target cell to serving DU 430. CU 410 may send the handover trigger condition together with LLM preparation. CU 410 may send LLM preparation in a UE context modification request. The UE context modification request message may include an RRC message and indicate the LLM configuration for one or more target cells.

[0150] At operation 901, if the serving DU 430 determines that both the first candidate target cell and the second candidate target cell verify their corresponding handover triggering conditions simultaneously, the CU 410 may further instruct the serving DU 430 to report to the CU 410. In this case, the CU 410 will select between the first and second candidate target cells.

[0151] At operation 902 , the serving DU 430 may confirm the receipt of the UE context modification request through another message (eg, a “UE context modification response” message sent to the CU 410 ).

[0152] At operation 903 , the UE may be configured with LLM configurations of the first and second candidate target cells, for example, through RRC Reconfiguration.

[0153] At operation 904 , the UE may confirm the receipt of the LLM configurations of the first and second candidate target cells through another message (eg, a “RRCReconfiguration Complete” message sent to the serving DU 430 ).

[0154] At operation 905, the serving DU 330 may send a UL RRC message transfer message to the CU 410 to transfer the received RRCReconfigurationComplete message.

[0155] At operation 906, UE 120 may send an L1 measurement report to serving DU 430. UE 120 may send the L1 measurement report periodically or in an event-based manner. The L1 measurement report may include the N strongest beams of both the serving cell and the first candidate target cell and the second candidate target cell. The measurement quantity used for L1 measurement may be, for example, RSRP, RSRQ, or L1-SINR.

[0156] At operation 907, the serving DU 430 may evaluate a first handover triggering condition for the first candidate target cell and a second handover triggering condition for the second candidate target cell. In particular, the serving DU 430 may evaluate the first and second handover triggering conditions in view of L1 measurement.

[0157] If the serving DU 430 determines that the first handover triggering condition is verified for the first candidate target cell and the second handover triggering condition is verified for the second candidate target cell, then at operation 908, the serving DU 430 may indicate to the CU 410 that the first handover triggering condition is verified for the first candidate target cell and the second handover triggering condition is verified for the second candidate target cell.

[0158] At operation 909, the CU 410 may receive slice information for the first and second candidate target cells from the target DU 330. The slice information may be received from the target gNB via an XnAP procedure. The slice information may be received during LLM preparation or in a resource status message.

[0159] At operation 910 , the CU 410 may select a target cell among first and second candidate target cells based on slice information.

[0160] In some embodiments, CU 410 may select a target cell based on the number of PDU sessions for the UE permitted by the candidate target cells. For example, CU 410 may select the first candidate target cell because it has permitted more PDU sessions for the UE.

[0161] In some embodiments, the CU 410 may select a target cell based on the load of the candidate target cells for at least one slice requested by the UE. For example, the CU 410 may select the first candidate target cell because the target DU 330 controlling the first candidate target cell has a lower load for at least one slice requested by the UE.

[0162] At operation 911, the CU 410 may send handover information to the serving DU 430. The handover information may include instructions for triggering a handover toward the selected candidate target cell (eg, the first candidate target cell). The CU 410 may send the instructions in a UE context modification request.

[0163] At operation 912 , the serving DU 430 may confirm the receipt of the instruction through another message (eg, a “UE Context Modification Response” message sent to the CU 410 ).

[0164] At operation 913, the serving DU 430 may trigger a handover towards the selected candidate target cell. The serving DU 430 may send a handover instruction to the UE 120, for example, via a MAC Control Element (MAC CE) message.

[0165] Fig.10is an example signaling diagram 1000 of a method according to an example embodiment. Some of the described operations may not be present in all example embodiments, and example embodiments may also include additional features / operations described elsewhere in this specification.

[0166] Can be Figure 4A The network node device central unit 410 and Figure 4B The service network node device distributed unit 430 performs at least part of the method of the schematic diagram 1000. Further features of the method of the schematic diagram 1000 are directly derived from Figure 4B The functions and parameters of the network node device central unit (CU) 410, the serving network node device distributed unit (serving DU) 430 and the target network node device distributed unit (target DU) 330 are described in detail and are therefore not repeated here. The method of the schematic diagram 1000 may be performed by a computer program.

[0167] Prior to operation 1001, CU 410 may receive at least one measurement report from UE 120. The measurement report may include L3 measurements. The measurement report may be used to identify at least one candidate target cell. In particular, the measurement report may be used to prove that the preparation conditions for the candidate target cell are verified. The candidate target cell may be hosted by the same target DU or different target DUs.

[0168] At operation 1001, the CU 410 may receive slice information for at least the first and second candidate target cells from the target DU 330. The slice information may be received from the target gNB via an XnAP procedure. The slice information may be received together with LLM preparation.

[0169] At operation 1002, the CU 410 may send handover information to the serving DU 430. The CU 410 may send the handover information in a UE context modification request.

[0170] The handover information may include a first handover triggering condition for a first candidate target cell and a second handover triggering condition for a second candidate target cell. The handover information may further include slice information for the first and second candidate target cells and a timer indicating the validity of the slice information. The validity of the slice information may mean that the UE is not allowed to initiate a handover when the timer is running and another condition is not met. The other condition may be a LLM condition that triggers toward another candidate cell. If the serving DU 430 determines that at least one of the candidate target cells verifies its associated handover triggering condition, the handover information may further include an instruction to start the timer.

[0171] At operation 1003 , the serving DU 430 may confirm the receipt of the UE context modification request through another message (eg, a “UE context modification response” message sent to the CU 410 ).

[0172] At operation 1004, the UE may be configured with LLM configurations of the first and second candidate target cells, for example, through RRC Reconfiguration.

[0173] At operation 1005 , the UE may confirm the receipt of the LLM configuration of the first and second candidate target cells through another message (eg, a “RRCReconfiguration Complete” message sent to the serving DU 430 ).

[0174] At operation 1006, the serving DU 330 may send a UL RRC message transfer message to the CU 410 to convey the received RRCReconfigurationComplete message.

[0175] At operation 1007, UE 120 may send at least one L1 measurement report to serving DU 430. UE 120 may send the L1 measurement report periodically or in an event-based manner. The L1 measurement report may include the N strongest beams of the serving cell and the first and second candidate target cells. The measurement quantity used for L1 measurement may be, for example, RSRP, RSRQ, or L1-SINR.

[0176] At operation 1008 , the serving DU 430 may evaluate a first handover triggering condition for the first candidate target cell and a second handover triggering condition for the second candidate target cell in view of L1 measurements for the first candidate target cell and the second candidate target cell.

[0177] If the serving DU 430 determines that the first handover triggering condition is verified for the first candidate target cell, at operation 807 , the serving DU 430 starts a timer (eg, T510 ).

[0178] At operation 1009 , the UE 120 may send a new L1 measurement report to the serving DU 430 .

[0179] At operation 1010 , the serving DU 430 may evaluate a second handover triggering condition for the second candidate target cell in view of a new L1 measurement report of the second candidate target cell.

[0180] If the serving DU 430 determines that the second handover triggering condition is verified for the second candidate target cell while the timer is running, the serving DU 430 may select one of the first or second candidate target cells based on the slice information at operation 1011. The serving DU 430 may also stop the timer.

[0181] In some embodiments, the serving DU 430 may select a candidate target cell based on the number of PDU sessions for the UE permitted by the candidate target cell. For example, the CU 410 may select the first candidate target cell because it has permitted more PDU sessions for the UE.

[0182] In some embodiments, the serving DU 430 may select a target cell based on the load of the candidate target cells for at least one slice requested by the UE. For example, the serving DU 430 may select the first candidate target cell because the target DU 330 controlling the first candidate target cell has a lower load for at least one slice requested by the UE.

[0183] If the timer expires before the handover triggering condition is verified for the second candidate target cell, the serving DU 430 may ignore the slice information and select the first candidate target cell for handover at operation 1011 .

[0184] At operation 1012, the serving DU 430 may trigger a handover towards the selected candidate target cell. The serving DU 430 may send a handover instruction to the UE 120, for example, via a MAC Control Element (MAC CE) message.

[0185] The functions described herein may be performed at least in part by one or more computer program product components (such as software components). According to an embodiment, the network node device central unit 410 and / or the service network node device distributed unit 430 may include a processor that is configured by program code to perform the described operations and functional embodiments when executed. Alternatively or additionally, the functions described herein may be performed at least in part by one or more hardware logic components. For example, but not limited to, illustrative types of hardware logic components that may be used include field programmable gate arrays (FPGAs), program-specific integrated circuits (ASICs), program-specific standard products (ASSPs), systems on chips (SOCs), complex programmable logic devices (CPLDs), and graphics processing units (GPUs).

[0186] Any range or device value given herein may be expanded or changed without losing the effect sought. In addition, any embodiment may be combined with another embodiment unless expressly prohibited.

[0187] Although the subject matter has been described using language specific to structural features and / or acts, it will be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Instead, the specific features and acts described above are disclosed as examples of implementing the claims, and other equivalent features and acts are intended to fall within the scope of the claims.

[0188] It will be understood that the benefits and advantages described above may relate to one embodiment, or may relate to several embodiments. The embodiments are not limited to embodiments that solve any or all of the problems described or embodiments that have any or all of the benefits and advantages described. It will also be understood that reference to an item may refer to one or more of these items.

[0189] The steps of the methods described herein may be performed in any suitable order, or simultaneously where appropriate. Additionally, individual blocks may be deleted from any one method without departing from the spirit and scope of the subject matter described herein. Aspects of any embodiment described above may be combined with aspects of any other embodiment described to form further embodiments without losing the effects sought.

[0190] The term "comprising" is used herein to mean including the identified methods, blocks or elements / components, but such blocks or elements / components do not include an exclusive list and the method or apparatus may contain additional blocks or elements / components.

[0191] It will be understood that the above description is given by way of example only, and that various modifications may be made by those skilled in the art. The above description, examples, and data provide a complete description of the structure and use of exemplary embodiments. Although various embodiments are described above with a certain degree of particularity or with reference to one or more separate embodiments, those skilled in the art may make many changes to the disclosed embodiments without departing from the spirit or scope of this specification.

Claims

1. A network node device central unit (410), comprising: at least one processor (412); as well as at least one memory (414) comprising computer program code; The at least one memory (414) and the computer program code are configured to, together with the at least one processor (412), cause the network node device central unit (410) to perform operations comprising: receiving (501) from a target network node device distributed unit (330) slice information for at least one candidate target cell hosted by the target network node device distributed unit (330); as well as Handover information to be used by the serving network node device distributed unit (430) to trigger a handover towards one of the at least one candidate target cells is sent (502) to a serving network node device distributed unit (430), the handover information being based on the slice information for the at least one candidate target cell hosted by the target network node device distributed unit (430).

2. The network node device central unit (410) according to claim 1, wherein The handover information includes the slice information for the at least one candidate target cell hosted by the target network node device distributed unit (330).

3. The network node device central unit (410) according to claim 1, wherein the operation further comprises: determining priority information related to a priority for triggering a handover to at least a first candidate target cell among the at least one candidate target cell, the priority being determined based on the slice information of the at least one candidate target cell; And wherein, the switching information includes the priority information.

4. The network node device central unit (410) according to claim 1, said operations further comprising: adjusting at least one radio handover triggering condition for the at least one candidate target cell based on the slice information for the at least one candidate target cell; And wherein the handover information includes an adjusted radio handover triggering condition for the at least one candidate target cell, the adjusted radio handover triggering condition to be associated by the serving network node device distributed unit (430) with at least one layer 1 L1 measurement used to make a handover decision.

5. The network node device central unit (410) according to claim 4, wherein: The at least one radio handover triggering condition includes at least one of the following: an offset, a threshold, or a trigger time, and wherein, based on the slice information of the at least one candidate target cell, adjusting the at least one radio handover triggering condition for the at least one candidate target cell includes: adjusting an offset of the at least one candidate target cell; adjusting a threshold of the at least one candidate target cell; or Adjusting a triggering time of the at least one candidate target cell.

6. The network node device central unit (410) according to claim 1, wherein: The at least one candidate target cell includes a first candidate target cell and a second candidate target cell, and the operation further includes: sending a first handover triggering condition for the first candidate target cell and a second handover triggering condition for the second candidate target cell to the serving network node device distributed unit (430), wherein the first handover triggering condition and the second handover triggering condition are associated by the serving network node device distributed unit (430) with at least one L1 measurement received from the user equipment (120); receiving an indication from the serving network node device distributed unit (430) that the first candidate target cell verifies the first handover condition and the second candidate target cell verifies the second handover condition; and selecting the first candidate target cell for handover based on slice information for the first candidate target cell and the second candidate target cell; And wherein, sending the switching information to the service network node device distributed unit (430) includes: sending an instruction for triggering switching to the first candidate target cell to the service network node device distributed unit (430).

7. The network node device central unit (410) according to claim 1, wherein: Sending the handover information to the serving network node device distributed unit (430) includes sending the slice information for the at least one candidate target cell and a timer indicating the validity of the slice information to the serving network node device distributed unit (430).

8. The network node device central unit (410) according to any one of claims 1 to 7, wherein: The slice information for the at least one candidate target cell includes an indication of at least one network slice that is allowed, rejected or remapped by the candidate target cell.

9. The network node device central unit (410) according to any one of claims 1 to 8, wherein: The slice information for the at least one candidate target cell includes the capability of the candidate target cell to perform network slice remapping.

10. A method comprising: receiving (501) from a target network node device distributed unit (330) slice information for at least one candidate target cell hosted by the target network node device distributed unit (330); as well as Sending (502) to a serving network node device distributed unit (430) handover information to be used by the serving network node device distributed unit (430) to trigger handover towards one of the at least one candidate target cells, the handover information being based on the slice information for the at least one candidate target cell hosted by the target network node device distributed unit (330).

11. A computer program comprising instructions for causing a network node device central unit to perform at least the following operations: receiving (501) from a target network node device distributed unit (330) slice information for at least one candidate target cell hosted by the target network node device distributed unit (330); and Sending (502) to a serving network node device distributed unit (430) handover information to be used by the serving network node device distributed unit (430) to trigger handover towards one of the at least one candidate target cells, the handover information being based on the slice information for the at least one candidate target cell hosted by the target network node device distributed unit (330).

12. A network node device central unit (410), comprising: means for receiving (501) from a target network node device distributed unit (330) slice information for at least one candidate target cell hosted by said target network node device distributed unit (330); as well as Means for sending (502) to a serving network node apparatus distributed unit (430) handover information to be used by the serving network node apparatus distributed unit (430) to trigger handover towards one of the at least one candidate target cells, wherein the handover information is based on the slice information for the at least one candidate target cell hosted by the target network node apparatus distributed unit (330).

13. A service network node device distributed unit (430), comprising: at least one processor (432); as well as at least one memory (434) comprising computer program code; The at least one memory (434) and the computer program code are configured to, together with the at least one processor (432), cause the serving network node device distributed unit (430) to perform operations comprising: Receiving handover information from a network node device central unit (410), the handover information being based on slice information for at least one candidate target cell hosted by a target network node device distributed unit (330); as well as The handover information is used to trigger a handover towards one of the at least one candidate target cell.

14. The service network node device distributed unit (430) according to claim 13, wherein: The handover information includes slice information for at least one candidate target cell hosted by the target network node device distributed unit (330).

15. The service network node device distributed unit (430) according to claim 13, wherein: The handover information includes priority information related to a priority for triggering a handover to at least a first candidate target cell among the at least one candidate target cell, the priority being based on the slice information for the at least one candidate target cell.

16. The service network node device distributed unit (430) according to claim 13, wherein: The handover information includes at least one adjusted radio handover triggering condition, where the at least one adjusted radio handover triggering condition is adjusted based on the slice information of the at least one candidate target cell; And wherein using the switching information includes: associating the at least one adjusted radio handover triggering condition with at least one L1 measurement received from a user equipment (120); and Based on the received at least one L1 measurement, it is determined whether the at least one adjusted radio handover triggering condition is met.

17. The service network node device distributed unit (430) according to claim 16, wherein: The at least one adjusted radio handover triggering condition includes at least one of the following: an adjusted offset, an adjusted threshold, or adjusted triggering time information.

18. The service network node device distributed unit (430) according to claim 13, wherein: The at least one candidate target cell includes a first candidate target cell and a second candidate target cell, and the operation further includes: Receiving a handover triggering condition for the first candidate target cell and a handover triggering condition for the second candidate target cell from the network node device central unit (410); associating the first handover triggering condition and the second handover triggering condition with at least one L1 measurement received from a user equipment (120); determining that the first candidate target cell verifies the first handover condition and the second candidate target cell verifies the second handover condition for the second candidate target cell; Sending an indication to the network node device central unit (410) that the first candidate target cell verifies the first handover condition and the second candidate target cell verifies the second handover condition for the second candidate target cell; And wherein, receiving the switching information from the network node device central unit (410) comprises: An instruction for triggering a handover to the first candidate target cell is received from the network node device central unit (410), wherein the first candidate target cell is selected based on the slice information.

19. The service network node device distributed unit (430) according to any one of claims 13 to 18, wherein: The slice information for the at least one candidate target cell includes an indication of at least one network slice that is allowed, rejected or remapped by the candidate target cell.

20. The service network node device distributed unit (430) according to any one of claims 13 to 19, wherein: The slice information for the at least one candidate target cell includes the capability of the candidate target cell to perform network slice remapping.

21. A method comprising: Receiving handover information from a network node device central unit (410), the handover information being based on slice information for at least one candidate target cell hosted by a target network node device distributed unit (330); as well as The handover information is used to trigger a handover towards one of the at least one candidate target cell.

22. A computer program comprising instructions for causing a service network node device distributed unit to at least perform the following operations: Receiving handover information from a network node device central unit (410), the handover information being based on slice information for at least one candidate target cell hosted by a target network node device distributed unit (330); and The handover information is used to trigger a handover towards one of the at least one candidate target cell.

23. A service network node device distributed unit (430), comprising: means for receiving handover information from a network node device central unit (410), wherein the handover information is based on slice information for at least one candidate target cell hosted by a target network node device distributed unit (330); and means for using the handover information to trigger a handover towards one of the at least one candidate target cell.

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