Optimization of access network deployment and performance in wireless network slices

Abstract

The present disclosure relates generally to wireless communication networks, and more particularly to methods, devices, network nodes, and systems for optimizing deployment and performance of wireless network slices. In particular, optimization of deployment and / or performance of a wireless network slice can be based on a set of slice-specific measurements performed by a wireless access network node serving the network slice and / or by a wireless terminal device served by the network slice. Measurements can be collected for a network slice in a minimization of drive tests (MDT) scheme. Such measurements can be provided to a trace collection entity (TCE) of the wireless network for further analysis. Such measurements and their reporting can be determined by MDT configuration data elements that identify a network slice and specify a type of measurement. The type of measurement can include measurements that facilitate detection of regional coverage holes for a network slice, mapping of network performance for a network slice that is specific to a region, and the like. Such slice-specific and / or region-specific MDT schemes can be particularly helpful in improving network slice deployment and coverage.

Description

Technical Field

[0001] This disclosure relates generally to wireless communication networks, and more particularly to methods, apparatus, network nodes, and systems for optimizing the deployment and performance of wireless network slices. Background Technology

[0002] In wireless communication systems, virtual network slices can be deployed to serve a group of wireless terminals. The services associated with a virtual network slice can be provided by a set of end-to-end lower-level access network nodes and core network nodes. Network resources can be allocated accordingly to support the network slice. The coverage and performance of a network slice in its various service areas may fluctuate over time due to various network conditions. Summary of the Invention

[0003] This disclosure generally relates to wireless communication networks, and more particularly to methods, apparatus, network nodes, and systems for optimizing the deployment and performance of wireless network slices. Specifically, the optimization of the deployment and / or performance of wireless network slices can be based on a set of slice-specific measurements performed by a radio access network node serving the network slice and / or by a wireless terminal device serving the network slice. Measurements can be collected for the network slice in a minimized drive test (MDT) scheme. Such measurements can be provided to a trace collection entity (TCE) of the wireless network for further analysis. Such measurements and their reports can be determined by MDT configuration data elements that identify the network slice and specify the type of measurement. The type of measurement may include measurements that help detect regional coverage blind spots of the network slice, perform region-specific mapping of the network performance of the network slice, etc. Such slice-specific and / or region-specific MDT schemes can be particularly helpful in improving network slice deployment and coverage.

[0004] In one example implementation, a method is disclosed performed by a radio access network node in a radio network configured to serve a network slice. The method may include receiving activation signaling for minimizing drive testing (MDT) from the core network of the radio network or from an Operation, Administration and Maintenance (OAM) network node, the activation signaling identifying the network slice; identifying user equipment (UE) connected to the radio access network node via the network slice in an Active Protocol Data Unit (PDU) session; collecting MDT measurements related to the UE; and sending an MDT report including the MDT measurements to a Tracking Collection Entity (TCE) of the radio network.

[0005] In the above example implementation, when a network resource shortage in a network slice is detected, MDT measurement items are collected.

[0006] In any of the above example implementations, a network resource shortage in a network slice is detected when the following occurs: the PDU session deletion process is triggered; multi-carrier resource sharing is triggered at the radio access network node to allocate network resources to the network slice; dual connectivity or carrier aggregation with different frequencies and overlapping coverage is initiated by the radio access network node for the UE; resource reallocation is initiated at the radio access network node to use network resources from the shared resource pool and / or the priority resource pool when dedicated or priority network resources are unavailable at the radio access network node; or the target radio access network node denies admission of the PDU session of the UE in network slice 1 during the handover preparation process.

[0007] In any of the above example implementations, the activation signaling includes an MDT configuration message; and the MDT configuration message includes an information element that instructs the radio access network node to collect and report deployment continuity measurements of network slices.

[0008] In any of the above example implementations, the MDT measurement item is generated by the radio access network node due to the failure of the UE to switch to another access network node within the network slice.

[0009] In any of the above example embodiments, after a radio access network node sends a handover request for the UE to another access network node and receives a handover request confirmation indicating the reason for the handover failure, it detects that the handover of the UE has failed.

[0010] In any of the above example implementations, the handover failure reason indicates at least one of the following: the other access network node does not support network slicing; or network resources are not available at the other access network node to support network slicing.

[0011] In any of the above example implementations, the MDT report includes at least one of the following: the location of the UE; first information of the source cell associated with the radio access network node; second information of the target cell associated with another access network node; and an indication of the reason for the failure to perform UE handover.

[0012] In any of the above example implementations, the activation signaling includes an MDT configuration message; and the MDT configuration message includes an information element that instructs the radio access network node to collect and report slice-specific measurements.

[0013] In any of the example implementations described above, the MDT configuration message also specifies the area range of slice-specific measurements for the network slice.

[0014] In any of the above example implementations, MDT measurements are collected by the radio access network node only when the UE is within the area.

[0015] In any of the above example implementations, the MDT measurements collected by the radio access network node include the data usage of the UE in the network slices within the area.

[0016] In any of the above example implementations, after the UE collects MDT measurements only when the UE is within the area of ​​the network slice, the MDT measurements are received from the UE by the radio access network node.

[0017] In another example implementation, a method is disclosed performed by a core network in a wireless network connected to a radio access network node, the core network and the radio access network node being configured to serve a network slice. The method may include sending an activation signaling message for Minimized Drive Testing (MDT) to the radio access network node, the activation signaling identifying the network slice; identifying a user equipment (UE) connected to the radio access network node via an active Protocol Data Unit (PDU) session through the network slice; receiving an MDT report from the radio access network node, the MDT report including UE-related MDT measurements collected by the radio access network node according to the activation signaling; and having a trace collection entity (TCE) of the core network perform an analysis of the deployment or performance of the network slice based on the MDT report.

[0018] In another example implementation, a method performed by a wireless terminal communicating with a radio access network node via a network slice in a wireless network is disclosed. The method may include establishing a Protocol Data Unit (PDU) session with the radio access network node within the network slice; collecting area-specific MDT measurements when the wireless terminal is within an area specified in a Minimum Drive Test (MDT) configuration of the network slice; and sending an MDT report containing the area-specific MDT measurements to the radio access network node for forwarding to a Tracking Collection Entity (TCE) of the wireless network.

[0019] In any of the above example implementations, when a network resource shortage in a network slice is detected, MDT measurements are collected.

[0020] In any of the above example embodiments, a network resource shortage in a network slice is detected when the following occurs: the PDU session deletion process is triggered; multi-carrier resource sharing is triggered at the radio access network node to allocate network resources to the network slice; dual connectivity or carrier aggregation with different frequencies and overlapping coverage is initiated by the radio access network node for the wireless terminal; resource reallocation is initiated at the radio access network node to use network resources from the shared resource pool and / or the priority resource pool when dedicated or priority network resources at the radio network access node are unavailable; or the target radio access network node denies admission of PDU sessions of wireless terminals in network slice 1 during the handover preparation process.

[0021] In any of the example implementations described above, the MDT configuration includes an information element that instructs the radio access network node to collect and report slice-specific measurements.

[0022] In any of the above example implementations, a cell identifier is used in the MDT configuration to specify the area range.

[0023] In any of the above example embodiments, the MDT measurements collected by the wireless terminal include the amount of data used by the wireless terminal in the network slices within the area.

[0024] A wireless terminal, network node, or core network in any of the above methods is disclosed. The wireless terminal, network node, or core network may include a processor and memory, wherein the processor is configured to read computer code from the memory, causing the wireless terminal, network node, or core network to execute any of the above methods.

[0025] A non-transitory computer-readable program medium storing computer code thereon is also disclosed. The computer code is configured to cause the processor to implement any of the methods described above when executed by a processor of a wireless terminal, network node, or core network according to any of the above methods.

[0026] The above embodiments and other aspects, as well as alternatives to their implementation, are described in more detail in the accompanying drawings, description, and claims. Attached Figure Description

[0027] Figure 1 An example wireless communication network is described, which includes a wireless access network, a core network, and a data network.

[0028] Figure 2 An example radio access network is described, which includes multiple mobile stations / terminals or user equipment (UEs) and radio access network nodes communicating with each other via an over-the-air wireless communication interface.

[0029] Figure 3An example radio access network (RAN) architecture is shown.

[0030] Figure 4 An example communication protocol stack is shown in a wireless access network node or wireless terminal device that includes various network layers.

[0031] Figure 5 The diagram illustrates the coverage blind spots of a network slice and an example of mapping the boundaries of the coverage blind spots via MDT measurements.

[0032] Figure 6 An example procedure is shown for configuring, executing, and reporting MDT measurements for detecting coverage discontinuities in network slices.

[0033] Figure 7 An example procedure for configuring, executing, and reporting region-specific MDT measurements is shown. Detailed Implementation

[0034] This disclosure will now be described in detail with reference to the accompanying drawings, which form a part of this disclosure and illustrate specific examples of embodiments by way of illustration. However, this disclosure may be implemented in a variety of different forms, and therefore the subject matter covered or claimed is intended to be construed as not being limited to any of the embodiments set forth below.

[0035] Throughout the specification and claims, terms may have subtle differences in meaning beyond what is explicitly stated, implied or suggested in the context. Similarly, the phrases “in one embodiment” or “in some embodiments” as used herein do not necessarily refer to the same embodiment, and the phrases “in another embodiment” or “in other embodiments” as used herein do not necessarily refer to different embodiments. For example, the claimed subject matter is intended to encompass, in whole or in part, exemplary embodiments or combinations of embodiments.

[0036] Generally, terms can be understood, at least in part, based on their usage in the context. For example, terms such as “and,” “or,” or “and / or” as used herein can include a variety of meanings, which can depend at least in part on the context in which they are used. Typically, “or,” when used to relate a list, such as A, B, or C, is intended to mean A, B, and C (in an inclusive sense) and A, B, or C (in an exclusive sense). Furthermore, the terms “one or more” or “at least one,” as used herein, can be used, at least in part, to describe any feature, structure, or characteristic in a singular sense, or to describe a combination of features, structures, or characteristics in a plural sense, depending at least in part on the context. Similarly, terms such as “a,” “an,” or “the” can also be understood to convey either a singular or a plural usage, depending at least in part on the context. Moreover, the terms “based on” or “determined by” can be understood not necessarily to convey an exclusive set of factors, but may allow for the existence of additional factors that are not necessarily explicitly described, again depending at least in part on the context.

[0037] This disclosure generally relates to wireless communication networks, and more particularly to methods, apparatus, network nodes, and systems for optimizing the deployment and performance of wireless network slices. Specifically, the optimization of the deployment and / or performance of wireless network slices can be based on a set of slice-specific measurements performed by a radio access network node serving the network slice and / or by a wireless terminal device serving the network slice. Measurements can be collected for the network slice in a minimized drive test (MDT) scheme. Such measurements can be provided to a trace collection entity (TCE) of the wireless network for further analysis. Such measurements and their reports can be determined by MDT configuration data elements that identify the network slice and specify the type of measurement. The type of measurement may include measurements that help detect regional coverage blind spots of the network slice, perform region-specific mapping of the network performance of the network slice, etc. Such slice-specific and / or region-specific MDT schemes can be particularly helpful in improving network slice deployment and coverage.

[0038] Wireless Network Overview Wireless communication networks such as Figure 1As shown in Figure 100, the example wireless communication network may include wireless terminal devices or user equipment (UEs) 110, 111, and 112, an operator network 102, various service applications 140, and other data networks 150. The wireless terminal devices or UEs may also be alternatively referred to as wireless terminals. For example, the operator network 102 may include access network nodes 120 and 121, and a core network 130. The operator network 102 may be configured to transmit voice, data, and other information (collectively referred to as data traffic) between the UE and the service application 140 or between the UE and other data networks 150. Access network nodes 120 and 121 may be configured as various wireless access network nodes (WANNs, alternatively referred to as wireless base stations) to interact with the UE at one end of the communication session and with the core network 130 at the other end. The term "access network" can be used more broadly to refer to the combination of wireless terminal devices 110, 111, and 112 with access network nodes 120 and 121. The radio access network can also be referred to as the radio access network (RAN). The core network 130 may include various network nodes configured to control communication sessions and perform network access management and traffic routing. Service applications 140 may be hosted by various application servers deployed outside of but connected to the core network 130. Similarly, other data networks 150 may also be connected to the core network 130.

[0039] exist Figure 1 In the example wireless communication network 100, each UE can communicate with each other through a wireless access network. For example, UE 110 and UE 112 can be connected to the same access network node 120 and communicate through the same access network node 120. Each UE can communicate with each other through both the access network and the core network. For example, UE 110 can be connected to access network node 120, and UE 111 can be connected to access network node 121, so UE 110 and UE 111 can communicate with each other through access network nodes 120 and 121, as well as the core network 130. UEs can also communicate with the service application 140 and the data network 150 through the core network 130. In addition, each UE can communicate directly with each other through sidelink communication (as shown in 113).

[0040] Figure 2An example system diagram of a radio access network 120 is also shown, which includes a WANN 202 serving UE 110 and UE 112 via an air interface 204. The radio transmission resources of the air interface 204 include a combination of frequency resources, time resources, and / or spatial resources. Each of UE 110 and UE 112 can be a mobile or fixed terminal device equipped with a mobile access unit such as a SIM / USIM (Subscriber Identity Module / Universal Subscriber Identity Module) module to access the wireless communication network 100. Both UE 110 and UE 112 can be implemented as terminal devices including, but not limited to, mobile phones, smartphones, tablets, laptops, in-vehicle communication devices, roadside communication devices, sensor devices, smart home appliances (such as televisions, refrigerators, and ovens), or other devices capable of wireless communication over a network. Figure 2 As shown, each of these UEs (such as UE 112) may include transceiver circuitry 206 coupled to one or more antennas 208 for enabling wireless communication with WANN 120 or another UE (such as UE 110). Transceiver circuitry 206 may also be coupled to processor 210, which may also be coupled to memory 212 or other storage devices. Memory 212 may be transient or non-transient and may store computer instructions or code that, when read and executed by processor 210, cause processor 210 to implement the methods described herein.

[0041] Similarly, WANN 120 may include a wireless base station or other wireless network access point capable of wirelessly communicating with one or more UEs via air interface 204 and with core network 130. For example, WANN 120 may not be implemented in the following forms: 2G base station, 3G nodeB, LTE eNB, 4G LTE base station, 5G NR base station of 5G gNB, 5G centralized unit base station, or 5G distributed unit base station. Each type of WANN can be configured to perform a corresponding set of wireless network functions. WANN 202 may include transceiver circuitry 214 coupled to one or more antennas 216, which may include various forms of antenna towers 218 to enable wireless communication with UE 110 and UE 112. Transceiver circuitry 214 may be coupled to one or more processors 220, which may be further coupled to memory 222 or other storage devices. The memory 222 may be transient or non-transient, and may store instructions or code that, when read and executed by one or more processors 220, cause one or more processors 220 to perform the various functions of the WANN 120 described herein.

[0042] like Figure 2 In the example shown, data packets in a radio access network can be transmitted as Protocol Data Units (PDUs). The data included can be encapsulated as PDUs at various network layers, with nested and / or layered protocol headers. When a connection is established between the transmitting and receiving ends (e.g., a radio link control (RRC) connection), communication between the transmitting device or receiving end (these terms are used interchangeably) and the receiving device or receiving end (these terms are also used interchangeably) can occur between the PDUs. Either the transmitting or receiving device can be a wireless terminal device (such as…) Figure 2 Devices 110 and 120), or wireless access network nodes (such as...) Figure 2 (Node 202). For bidirectional communication, each device can be both a sending device and a receiving device.

[0043] Figure 1 The core network 130 may include various geographically distributed and interconnected network nodes to provide network coverage to the service area of ​​the carrier network 102. These network nodes may be implemented as dedicated hardware network nodes. Alternatively, these network nodes may be virtualized and implemented as virtual machines or software entities. Each of these network nodes may be configured with one or more types of network functions, which together provide resource provisioning and routing capabilities for the core network 130.

[0044] Return to the wireless radio access network (RAN). Figure 3 An example RAN 340 communicating with core network 310 and radio terminals UE1 through UE7 is shown. RAN 340 may include one or more types of radio base stations or WANN 320 and WANN 321, which may include, but are not limited to, gNB, eNodeB, NodeB, or other types of base stations. RAN 340 may perform backhaul with core network 310. For example, WANN 320 may further include multiple independent access network nodes in the form of a Central Unit (CU) 322 and one or more Distributed Units (DUs) 324 and 326. CU 322 is connected to DU1 324 and DU2 326 via various interfaces (e.g., F1 interfaces). For example, the F1 interface may further include F1-C and F1-U interfaces, which may be used to carry control plane information and user plane data, respectively. In some embodiments, CU may be a gNB Central Unit (gNB-CU), and DU may be a gNB Distributed Unit (gNB-DU). While the various implementations described below are provided in the context of 5G cellular wireless networks, the basic principles described herein are also applicable to other types of radio access networks, including but not limited to other generations of cellular networks and wireless local area networks (WLANs). Fi, Bluetooth, ZigBee, and WiMax (Worldwide Interoperability for Microwave Access) networks.

[0045] Each UE can be connected to the network via the air interface through the WANN 320. Each UE can be served by at least one cell. Each cell is associated with a coverage area. These cells may also be referred to as serving cells. The coverage areas between cells may partially overlap. Each UE can actively communicate with at least one cell when it is potentially connectable to or able to connect to more than one cell. Figure 1 In the example, UE1, UE2, and UE3 can be served by cell 1 330 of DU1, while UE4 and UE5 can be served by cell 2 332 of DU1, and UE6 and UE7 can be served by cell 3 associated with DU2. In some implementations, a UE can be served by two or more cells simultaneously. Each UE can be mobile, and the signal strength and quality from the various cells at the UE can depend on the UE's location and mobility.

[0046] In some example implementations, Figure 3The cells shown can be alternatively referred to as serving cells. Serving cells can be grouped into serving cell groups (CGs). A serving cell group can be a master CG (MCG) or a secondary CG (SCG). Each type of cell group may contain one master cell and one or more secondary cells. For example, a master cell in an MSG may be referred to as a PCell, while a master cell in an SCG may be referred to as a PScell. Secondary cells in either an MCG or an SCG may be referred to as SCells. Master cells, including both PCells and PScells, may be collectively referred to as special cells (spCells). All of these cells may be referred to as serving cells or simply cells. Unless otherwise specified, the terms "cell" and "serving cell" are generally used interchangeably. The term "serving cell" can refer to a cell that is currently serving, will be serving, or may be serving a UE. In other words, a "serving cell" may not currently be serving a UE. Although the various embodiments described below may sometimes refer to one of the types of serving cells described above, the basic principles apply to all types of serving cells in both types of serving cell groups.

[0047] Figure 4 Further demonstrated in Figures 1 to 3 A simplified diagram of the various network layers involved in transmitting user plane PDUs from transmitting device 402 to receiving device 404 in an example wireless access network. Figure 4 It is not intended to include all the necessary equipment components or network layers for handling the transmission of PDUs. Figure 4 This illustrates that data encapsulated in the higher-level network layer 420 of the transmitting device 402 can pass through the packet data convergence protocol (PDCP) layer of the transmitting device. Figure 4 The PDUs (not shown in the diagram) and Radio Link Control (RLC) layer 422, the physical (PHY) layers and radio interfaces of the transmitting and receiving devices (as shown in 406), and the media access control (MAC) layer 434 and RLC layer 432 of the receiving device are transmitted to the corresponding higher layer 430 of the receiving device 304 (such as the Radio Resource Control or RRC layer). Various network entities in each of these layers can be configured to handle the transmission and retransmission of PDUs.

[0048] exist Figure 4 In this context, the higher layer 420 can be referred to as layer 3. 3) or L3, while each intermediate layer (such as RLC layer and / or MAC layer and / or PDCP layer) (in Figure 4 (not shown in the image) can be collectively referred to as layer 2. 2) or L2, and the term Layer 1 is used to refer to layers such as the Physical Layer and the Radio Interface Association Layer. In some instances, the term "lower layer" can be used to refer to the set of L1 and L2, while the term "higher layer" can be used to refer to Layer 3. In some cases, the term "lower layer" can be used to refer to layers in L1, L2, and L3 that are lower than the current reference layer. Control signaling can be initiated and triggered within each of the layers L1 through L3 and the various network layers within them. These signaling messages can be encapsulated and concatenated into lower layer packets and transmitted through allocated control or data air radio resources and interfaces. The term "layer" typically includes its various corresponding entities. For example, the MAC layer covers the corresponding MAC entities that can be created. Layer 1, for example, covers the PHY entity. Layer 2, in turn, covers, for example, the MAC layer / entity, the RLC layer / entity, the Service Data Adaptation Protocol (SDAP) layer, and / or the PDCP layer / entity.

[0049] This disclosure describes techniques that can be implemented for exchanging information between the network and the UE and / or between network nodes (e.g., from gNB-DU to gNB-CU, from gNB-CU to gNB-DU, from source cell to target cell, from SN to MN, from MN to SN).

[0050] In some embodiments, the network can be an eNB, ng-eNB, or gNB; the UE can be configured with single carrier, carrier aggregation (CA), or dual connectivity (DC). For DC, MN can be an eNB, ng-eNB, or gNB; and SN can be an eNB, ng-eNB, or gNB, but is not limited to 4G or 5G network devices.

[0051] Wireless network slicing For certain application scenarios in wireless networks, Network Function Virtualization (NFV) technology can be implemented. This technology enables wireless network operators to utilize the aforementioned... Figures 1 to 4 The document describes a set of underlying network components used to construct different virtual networks, thereby providing services to customers with varying business needs. For example, each such virtual network can be implemented as a wireless network slice. Wireless network slices can be based on common physical infrastructure (e.g., the aforementioned...). Figures 1 to 4The general physical infrastructure described in the document logically defines and divides the network to form an end-to-end virtual network. Each virtual network or network slice can be configured with different functions and characteristics to dynamically meet various network requirements. For example, in addition to regular control plane functions, some network slices may include a dedicated forwarding plane, while some network slices may only include some basic control plane functions (not all control plane functions).

[0052] For a concrete example, the resources of a group of base stations and core network nodes / components can be aggregated in an end-to-end manner to form a virtual wireless network, such as a network slice, to provide network services to a group of wireless terminals or user equipment. A network slice can be configured to provide network services covering desired geographic areas or service regions, which can be contiguous or distributed. For example, a wireless network slice can be deployed for an enterprise located in one or more contiguous or distributed geographic regions to cover the wireless terminals or user equipment associated with that enterprise within those geographic areas or regions.

[0053] Multiple wireless network slices can be implemented based on a pool of network components in a public infrastructure (such as the aforementioned radio access network nodes and various core network components). Each wireless network slice can be provided by a subset of network components from the pool. Each subset of network components can be deployed for a specific wireless network slice and can be adjusted, modified, and reconfigured over time for that specific wireless network slice. The service areas of multiple network slices can overlap. For example, all or part of the offices / facilities of two enterprises served by two independent wireless network slices can co-locate. In this way, the same network components, especially the same radio access network nodes, can be configured to support two wireless network slices. Thus, in some cases, different wireless network slices can share the same subset of radio communication resources (e.g., radio resources in frequency, time, and space).

[0054] Virtual networks, such as wireless network slicing, can be deployed and operated in a wide variety of complex ways to suit the business needs of the enterprise served by such a network. For example, wireless network slicing can include further enhancements supporting slice-based cell reselection, slice-based random access channel (RACH) configuration, and service continuity. As another example, network slicing can be further enhanced to support non-uniform deployment. Such enhancements may affect varying degrees of impact. Figures 1 to 4The implementation of various components of the wireless network described herein. This complexity in network slicing implementation may necessitate continuous monitoring and evaluation of the coverage and network performance of these network slices, enabling adaptive and real-time adjustments to their configuration, resource allocation, and other aspects.

[0055] Network monitoring and minimized drive testing (MDT) In some example implementations, a Minimum Drive Test (MDT) scheme can be used to obtain network operation information such as coverage boundaries, data volume, and general communication performance. The coverage and service quality of a deployed radio access network can be measured through drive tests. An MDT scheme can be used instead of traditional drive tests, which involve using a dedicated vehicle equipped with radio receiving and transmitting equipment and being driven by an operator throughout the service area to collect network operation data. Metrics such as coverage boundaries and radio signal quality are then extracted and analyzed from this data to improve the deployment and performance of the radio access network. Instead, in an MDT scheme, user equipment (UEs) or radio terminal equipment (RTOs) entering, passing through, and leaving the service area of ​​the radio network can provide network measurements. The MDT can be configured and subsequently activated by the core network. This configuration can specify which UEs should participate, and how, when, and where various measurements should be performed and reported.

[0056] In some example implementations, MDTs can be categorized into management-based MDTs and signaling-based MDTs. The activation process for a management-based MDT may include (applicable to general radio systems, but using an E-UTRAN system as an example only): the OAM (Operation and Maintenance Management, or Network Management System) sends a trace activation message (e.g., a trace session activation message) to a base station (e.g., an eNodeB) containing the configured MDT, where the trace activation message specifies the test area; the base station selects appropriate UEs within the specified area and sends the MDT configuration information to the selected UEs within the specified area. However, the activation process for a signaling-based MDT may include: the OAM sending a trace activation message (e.g., a trace session activation message) to the HSS (Home Subscriber Server) containing the MDT configuration for multiple specified UEs to activate MDT measurements for the specified UEs; the HSS sending the MDT configuration information for these UEs to the Mobile Management Entity (MME); the MME sending the MDT configuration information for these UEs to the base station (e.g., an eNodeB); and the base station ultimately sending the MDT configuration information to these UEs.

[0057] In some example implementations, the UE can be specified using signaling-based IMSI (International Mobile Subscriber Identity) or IMEI (International Mobile Station Equipment Identity) in the MDT configuration information. In some example implementations, region or geographical information can be added to restrict the selection of UEs participating in the MDT. In some example implementations, additional tracking reference activation messages (e.g., managed tracking reference activation messages and signaling-based tracking reference activation messages) can be implemented, which include tracking reference information from the OAM, including, for example, public land mobile network information, which may include the Mobile Country Code (MCC) and Mobile Network Code (MNC).

[0058] Applying MDT to network slicing deployment and optimization The aforementioned general MDT solution can be adapted to provide network slice-specific monitoring, measurement, and reporting.

[0059] In some example implementations, specific indication or information elements may be included in the MDT configuration for implementing network slice-specific MDT configuration and activation, as described in further detail below. Furthermore, different information elements in the MDT configuration can be used to specify and activate different types of MDT measurements / reports separately.

[0060] The MDT configuration information for a network slice can be sent to a group of base stations supporting that network slice. These base stations can then configure, activate, and report MDT measurements accordingly. The core network can configure MDT measurements / reporting for multiple network slices. Therefore, a base station can receive an MDT configuration containing multiple MDT information elements to configure each of the multiple network slices it supports. Each of these MDT information elements can be identified by a network slice ID (e.g., S-NSSAI or individual network slice selection auxiliary information).

[0061] For some types of MDT measurements, a set of UEs can be specified to perform MDT measurements. In this case, the UEs can be provided with an MDT configuration containing such MDT information items so that the UEs can configure, activate and report the configured measurements accordingly.

[0062] In some example implementations, as described in further detail below, regional or geographic restrictions may be included in the MDT information items for configuring the MDT of a network slice. Therefore, a mechanism is also provided for configuring and activating region-specific or geographic-specific MDTs throughout the entire service area of ​​a network slice, as described in further detail below.

[0063] In some example implementations, the configured and activated MDT measurements described above can be reported to the core network. Such reports can be provided based on reporting configurations, for example, those included in one or more MDT configuration information elements within a network slice. For instance, the collected MDT measurement information can be provided to the core network's Tracking Collection Entity (TCE). The TCE can analyze the collected information to extract or generate results such as coverage blind spots, performance maps, data volume maps, and Quality of Service (QoS) maps for the network slice (whether for the entire region or within a specific sub-region or sub-domain of the network slice's intended service coverage area). Optimization schemes supporting the deployment and / or adjustment of network components can also be generated for the network slice.

[0064] Network Slicing Service Continuity Measurement under MDT In some example implementations, network slice service continuity measurement using an MDT scheme can be configured, as described in further detail below.

[0065] Specifically, in some cases, the network slice resources allocated to a deployed network slice may become insufficient in certain areas or regions that the network slice is intended to cover. Therefore, UEs associated with that network slice may be unable to use the slice's services in these areas. These areas can be referred to as service blind spots. Network slices with such service blind spots can be referred to as network slices suffering from network slice deployment discontinuity.

[0066] Such service blind spots may appear or arise after network slicing deployment for various reasons, including but not limited to network component failures / outages in these areas, or a sudden surge in the number of terminal devices requiring support in these areas. These service blind spots may be temporary or long-term. However, regardless of whether these blind spots are temporary or long-term, the network may want to detect, measure, and record such blind spots, along with information that can be used to infer when such service blind spots occurred (e.g., start time, duration, etc.), in order to optimize network slicing in the future. The example implementations provided below help operators quickly locate such service blind spots, or pinpoint areas or regions where network slice deployment is faulty, through new MDT measurements.

[0067] Figure 5 This illustrates an example service blind spot in a network slice within an otherwise contiguous coverage area. Figure 5In the diagram, the shaded area and the surrounding white area together illustrate the intended coverage area of ​​the example network slice S-NSSAI=1 deployed by the operator. According to the network plan, the entire area fully supports the S-NSSAI=1 network slice, and the UE can use the network slice's services within this area. However, the surrounded white area in the diagram represents an actual service blind spot within the service slice, due to factors such as congestion at a radio base station located within it, or the planned network slice not actually being deployed in the area for some reason. Therefore, when a UE in the RRC_CONNECTED state associated with this network slice (as indicated by the arrows) crosses the white area, the PDU session between the UE and the S-NSSAI=1 network slice may be interrupted (when the UE enters the service blind spot) and then resumed (when the UE exits the service blind spot and moves to the shaded area covered by the network slice's services).

[0068] The following example implementation allows a base station (e.g., an NG-RAN node) to generate one or more MDT reports in the scenario described above. The MDT reports record these locations (e.g., by...) Figure 5 Following the location indicated by the small circle in the diagram, the location where the PDU session interruption occurred (e.g., in the form of cell ID information) is effectively recorded. This one or more MDT reports can be sent to the TCE for analysis. By providing MDT reports from a sufficient number of UEs or interruption events in this manner, the TCE can analyze and identify service blind spots (i.e., areas where S-NSSAI=1 network slices have abnormal network slice deployments) within the network. Figure 5 (The white area in the middle).

[0069] To achieve the above objectives, a new MDT measurement type can be defined and configured. This new measurement type can be called Network Slice Service Continuity Measurement. This Network Slice Service Continuity Measurement can be configured and activated separately from other types of MDT measurements, or as an alternative to other types of MDT measurements.

[0070] This network slicing service continues to be measured and can be configured and activated by the core network. For example, the MDT configuration can be generated by the core network and provided to the base station. The network nodes or entities in the core network responsible for generating this MDT configuration can include, but are not limited to, OAM or AMF network nodes or network functions.

[0071] This MDT configuration can be provided to the base station by the core network via network configuration signaling messages (e.g., RRC signaling messages). The MDT configuration signaling message may include one or more MDT configuration information elements. These one or more MDT configuration information elements may include configuration information for novel network slice continuity measurements.

[0072] Table 1 shows an example MDT configuration that includes multiple information elements.

[0073] Table 1

[0074] In the example in Table 1, a specific information element, referred to as "Slice Deployment Continuity Measurement," may be included to configure such measurements so that TCE can identify service blind spots in network slices. This information element may include a set of parameters for configuring the service deployment continuity measurement. Table 2 shows an example. As shown in Table 2, network slice service continuity measurement parameters include at least network slice information, such as identification information for the network slice list. These parameters may also include the configuration for the network slice service continuity measurement.

[0075] Table 2: Information Element (IE) defines the parameters for continuous measurement collection during slice deployment.

[0076]

[0077] Figure 6 An example procedure for configuring and activating the above-mentioned MDT measurements is shown. This example procedure may include the following steps.

[0078] exist Figure 6 In step 0, the core network node or function, such as OAM or AMF, can be one or more access network nodes (e.g., Figure 6 The example shown is gNB1) configured with an MDT. For instance, the OAM or AMF in the core network can send MDT configuration information to the base station associated with the target network slice (S-NSSAI = 1), such as gNB1. As mentioned above, the configuration information may contain information elements indicating the deployment of continuous measurements for slices of new measurement types.

[0079] After receiving this measurement type, the base station (e.g.) Figure 6 The gNB1 can monitor one or more UEs associated with an indicated network slice to detect connectivity discontinuities within the network slice. As an example only, a base station can determine a discontinuity when resource scarcity is detected in a target network slice (e.g., a network slice with S-NSSAI = 1) under one or more of the following scenarios, indications, or conditions: ● The base station (e.g., gNB1) triggers a deletion procedure for the PDU session of the UE in the network slice. The deletion procedure may include, for example, when the base station triggers the NGAP protocol's PDU session resource notification procedure and notifies the AMF that the PDU session has been deleted.

[0080] ● The base station (e.g., gNB1) decides to use multi-carrier resource sharing to allocate resources for the target network slice.

[0081] ● The base station (e.g., gNB1) decides to establish dual connectivity or carrier aggregation with different frequencies and overlapping coverage.

[0082] ● The base station (e.g., gNB1) decides to use resource reallocation, which means that when the target network slice’s own dedicated or priority resources are unavailable, the PDU sessions in the target network slice actually use resources from the shared pool and / or priority pool.

[0083] ●When the target base station rejects network slice access for the target network slice of the UE's PDU session, and the rejection reason value is "slice not supported".

[0084] ● When the target base station denies network slice access for the target network slice of the UE's PDU session, and the denial reason value is "resources are not available for the slice".

[0085] exist Figure 6 In a further step, the switching failure is used to indicate resource shortages in a network slice. The basic principles of these steps apply to the detection of resource shortages in network slices and other scenarios.

[0086] exist Figure 6 In step 1, the UE can establish at least one PDU session belonging to the network slice configured by the MDT (e.g., a network slice with S-NSSAI = 1). Specifically, at the base station (e.g., Figure 6 Before the gNB1) starts the configured MDT measurement, the UE should have established at least one PDU session with S-NSSAI = 1. Otherwise, the base station cannot know the UE's usage of network slice resources and therefore cannot trigger any configured MDT measurement.

[0087] exist Figure 6 In steps 2 and 3, during the handover preparation period, the target base station (e.g., gNB2) may refuse to grant the UE access to a network slice with S-NSSAI = 1. Specifically, the source base station may trigger the UE's handover preparation process by sending a handover request to the target base station gNB2, but the target base station gNB2 may refuse the request because, for example, it does not support network slices with S-NSSAI = 1 or there are no resources available for network slices with S-NSSAI = 1.

[0088] exist Figure 6In step 4, base station gNB1 can generate an MDT report. Specifically, base station gNB1 can record information items in the MDT report, including, for example, the UE's location, cell information, source cell information, target cell information, and the reason value or index for network slice unavailability (including, for example, network slice is not supported or resources are not available for network slice, as described above).

[0089] exist Figure 6 In step 5, base station gNB1 can send an MDT report to the TCE of the core network (or alternatively, the TCE can be implemented independently of the core network).

[0090] exist Figure 6 In step 6, the TCE can provide MDT report analysis after receiving the MDT reports. After collecting a sufficient number of discontinuity MDT reports from the various UEs associated with the network slice, the TCE can analyze these MDT reports to extract the discontinuities of the network slice with S-NSSAI=1 and provide optimization recommendations to the operator. For example, based on the analysis results, the operator determines whether to deploy additional resources in the area for, for example, the network slice with S-NSSAI=1.

[0091] Network slice-based region range for MDT measurements In some scenarios where network slicing has been deployed, network slice resources may become insufficient across the entire network slice or within some sub-areas or sub-regions of a network slice (e.g., some cells supporting network slicing) (even though service has not been interrupted and remains available). This can lead to a decrease in the QoS of UEs associated with the entire network slice or the QoS of UEs located within some sub-areas or regions of the network slice. The following section describes in more detail the mechanism for defining slice-based regional scopes for MDT measurements in the MDT configuration to help network operators quickly identify slice-level QoS issues and / or QoS issues of specific slices in specific sub-areas or regions.

[0092] For example, an operator can deploy a network slice with S-NSSAI=1 in a wireless network. For instance, according to network planning, the entire service area can fully support the deployed S-NSSAI=1 network slice. However, the resources of the network slice may become insufficient (temporarily or permanently) throughout the slice or in some sub-areas or regions of the slice. Therefore, the QoS of the S-NSSAI=1 network slice used by the UE may degrade throughout the slice or in these sub-areas or regions.

[0093] In the example implementations described in further detail below, network slice-based area scope configurations can be carried in various ways in MDT configuration signaling messages from the core network (e.g., OAM or AMF) to the base station and / or UE. The slice-based area scope may involve one or more entire network slices or sub-areas / regions of these network slices. When a UE associated with a network slice involved in the slice-based area scope configuration traverses these network slices or designated sub-areas / regions of these network slices, if the UE is in the RRC_CONNECTED state and has established at least one PDU session belonging to the involved network slice, the base station and / or UE can initiate MDT measurements (e.g., M4 data volume measurement) as configured. The measurement information can be sent to the TCE for analysis. Through the MDT reports thus provided, the TCE can analyze the quality of service of these network slices or their sub-areas / regions. The new MDT measurement configuration parameters related to the area range can be specified in various example ways as described below. This provides network operators with flexible options for slice-specific and / or sub-area / region-specific MDTs to quickly identify QoS issues of network slices in their entirety or in specific sub-areas or regions for resource and network optimization purposes.

[0094] Table 3 illustrates an example of MDT configuration. Specifically, in the MDT configuration, a slice list can be added as one of the area range options (shown as an underlined bold row in Table 3) in addition to other MDT area range options (e.g., cell-based, TA-based, PLMN wide, TAI-based area range options, etc.) to achieve slice-specific MDT area range configuration. The slice list can contain the S-NSSAI list of network slices. If the area range option is configured to be network slice-specific, when a UE supporting at least one PDU session belonging to a network slice on the slice list moves to the area of ​​that network slice, the base station and the UE will collect MDT reports according to the MDT configuration. In other areas entered by the UE, the base station and the UE do not collect MDT reports. In this example implementation, once the slice-specific area range is configured, the configured MDT measurements are collected and reported for the entire configured network slice.

[0095] Table 3

[0096] In Table 3 above and Table 4 below, “TA” represents “Tracking Area”, “TAC” represents “Tracking Area Code”, “TAI” represents “Tracking Area Identifier”, “CGI” represents “Global Cell Identifier”, “PLMN” represents “Public Land Mobile Network”, “PNI” represents “Public Network Integration”, “CAG” represents “Closed Access Group”, “NPN” represents “Non-Public Network”, “SNPN” represents “Standalone NPN”, and “NID” represents “Network ID”.

[0097] Table 4 illustrates another example of MDT configuration. Specifically, a slice list can be added to indicate the MDT area range (as shown in the underlined bold rows in Table 4). Unlike Table 3 above, where the slice list is one of the MDT area range options, the added slice list can be used in conjunction with other MDT area range options. For example, a cell-based MDT area range can be configured in the MDT area range options of Table 4. Such a cell-based (as specified by the cell list) area range can be used in conjunction with a separate MDT area range specified by the slice list, making the configured MDT measurements both network slice-specific and cell-specific. In this way, the configured MDT measurements can be flexibly restricted / adapted to specific sub-regions / areas (e.g., specific cells configured by the cell list in the MDT configuration area range options) and specific slices (configured by the slice list). When a UE supporting at least one PDU session belonging to a network slice in the slice list moves to a sub-region / area indicated by the cell list of the network slice, the base station and the UE collect MDT reports according to the MDT configuration. In other areas entered by the UE, the base station and the UE do not collect MDT reports. In this example implementation, the slice-specific region range is configured separately from other region range options and used in conjunction with another selected region range, thereby flexibly limiting / adapting MDT measurements and reporting to configurable sub-regions / areas of the network slice.

[0098] Table 4

[0099] The example MDT configurations in Tables 3 and 4 above are merely examples. Other ways to configure MDT measurements to implement slice-specific MDT measurements or restrict MDT measurements to sub-regions / regions within selected network slices are not limited to these examples. For instance, a specific sub-region / region is not limited to cells. Such a sub-region or region could be, for example, a cell group, a PLMN region, etc. (as specified as other area range options in the MDT configurations of Tables 3 and 4).

[0100] Figure 7 An example workflow for slice-specific or sub-region / region-specific MDT measurements and reporting using the MDT configuration described above is shown.

[0101] exist Figure 7 In step 0, the OAM or AMF configures the MDT for the base station. Specifically, in the MDT configuration sent to the base station by the OAM or AMF, the aforementioned slice list information element can be included as an option for MDT area range, or as a slice-specific restriction on other area range options. At least the ID of the network slice to be measured must be included. When the base station (e.g., Figure 7 When the base station (gNB) and UE receive a new slice area range, the base station and / or UE begin area range measurement. Measurement reports can be collected by the base station and sent to the TCE. The TCE analyzes the quality of service of the network slice based on the measurement reports.

[0102] exist Figure 7 In step 1, the UE has already established at least one PDU session belonging to a network slice (e.g., S-NSSAI = 1). According to this example, at least one PDU session belonging to a network slice, such as S-NSSAI = 1, should be established for the UE before the base station begins measurement. Otherwise, the base station cannot know the UE's usage of network slice resources and cannot trigger the measurement.

[0103] exist Figure 7 In step 2, the base station can collect MDT reports of MDT measurements (e.g., M4 measurements providing data usage information for the UE). Based on the example configuration above, such MDT measurements can be slice-specific and / or specific to a particular sub-region / area of ​​a configured network slice.

[0104] exist Figure 7 In step 3, the base station can provide the aforementioned MDT report to the TCE.

[0105] exist Figure 7 In step 4, the UE can collect MDT measurements and generate one or more MDT reports. Similarly, based on the example configuration above, such MDT measurements can be slice-specific and / or specific to a particular sub-region / area of ​​a particular network slice.

[0106] exist Figure 7 In steps 5 and 6, the UE can provide the collected MDT reports to the TCE via the base station.

[0107] exist Figure 7 In step 7, the TCE can receive the MDT report and perform analysis. Based on other reports within the same slice and / or sub-region / region of the network slice, the TCE can analyze whether there are faults in the slice resources within the measured area and provide optimization recommendations to the operator at the slice level and / or sub-region / region level. The operator determines whether to modify the slice resource configuration of the network slice or a specific sub-region / region of the network slice based on the analysis results.

[0108] Therefore, the above example implementation provides network operators with a region-specific MDT measurement configuration scheme and process for flexible and configurable slice-specific and / or sub-region / region-specific MDT measurements and reporting, so as to quickly identify QoS issues of network slices in their whole or in specific sub-regions or regions for resource and network optimization purposes.

[0109] The above description and accompanying drawings provide specific example embodiments and implementations. However, the described subject matter can be implemented in a variety of different forms, and therefore, the covered or claimed subject matter is intended to be construed as not being limited to any of the example embodiments set forth herein. A reasonably broad scope is intended for the claimed or covered subject matter. In particular, for example, the subject matter can be implemented as a method, apparatus, component, system, or non-transitory computer-readable medium for storing computer code. Thus, embodiments can take the form of hardware, software, firmware, storage media, or any combination thereof. For example, the above-described method embodiments can be implemented by a component, apparatus, or system including a memory and a processor by executing computer code stored in the memory.

[0110] Throughout the specification and claims, terms may have subtle differences in meaning beyond what is explicitly stated, implied or suggested in the context. Similarly, the phrase "in one embodiment / implementation" as used herein does not necessarily refer to the same embodiment, and the phrase "in another embodiment / implementation" as used herein does not necessarily refer to different embodiments. For example, the claimed subject matter is intended to include, in whole or in part, a combination of exemplary embodiments.

[0111] References to features, advantages, or similar language throughout this specification do not imply that all features and advantages achievable using this solution should be, or be included, in any single implementation of this solution. Rather, language relating to features and advantages is understood to mean that a particular feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of this solution. Therefore, descriptions of features and advantages and similar language throughout this specification may, but are not necessarily, of the same embodiment.

[0112] Furthermore, the features, advantages, and characteristics described herein can be combined in any suitable manner in one or more embodiments. Those skilled in the art will recognize that, based on the description herein, this solution can be implemented without one or more specific features or advantages of a particular embodiment. In other instances, additional features and advantages that may not be present in all embodiments of this solution may be recognized in certain embodiments.

Claims

1. A method performed by a radio access network node in a wireless network configured to serve network slicing, comprising: Receive activation signaling for minimizing drive test MDT from the core network of the wireless network or from the operation, maintenance and management (OAM) network node, wherein the activation signaling identifies the network slice; Identify the user equipment (UE) connected to the radio access network node via the network slice using an Active Protocol Data Unit (PDU) session; Collect MDT measurement items related to the UE; as well as The MDT report, which includes the MDT measurement items, is sent to the Tracking Collection Entity (TCE) of the wireless network.

2. The method according to claim 1, wherein, When a network resource shortage is detected in the network slice, the MDT measurement items are collected.

3. The method according to claim 2, wherein, A network resource shortage is detected in the network slice when the following conditions occur: The deletion process of the PDU session is triggered; At the wireless access network node, multi-carrier resource sharing is triggered to allocate network resources to the network slice; The radio access network node initiates dual connectivity or carrier aggregation with different frequencies and overlapping coverage for the UE; Initiate resource reallocation at the wireless access network node to use network resources from the shared resource pool and / or the priority resource pool when dedicated or priority network resources at the wireless network access node are unavailable. or The target radio access network node denies access to the PDU session of the UE in network slice 1 during the handover preparation process.

4. The method according to claim 2, wherein: The activation signaling includes an MDT configuration message; and The MDT configuration message includes an information element that instructs the radio access network node to collect and report deployment continuity measurements of the network slice.

5. The method according to claim 4, wherein, The MDT measurement item is generated by the radio access network node due to the failure of the UE to switch to another access network node within the network slice.

6. The method according to claim 5, wherein, After the radio access network node sends a handover request for the UE to the other access network node and receives a handover request confirmation indicating the reason for the handover failure, it detects that the handover of the UE has failed.

7. The method according to claim 6, wherein, The reason for the handover failure indicates at least one of the following: The other access network node does not support the network slice; or Network resources are not available at the other access network node to support the network slice.

8. The method according to claim 5, wherein, The MDT report includes at least one of the following: The location of the UE; First information about the source cell associated with the wireless access network node; Second information about the target cell associated with the other access network node; Indicate the reason for the UE handover failure.

9. The method according to claim 2, wherein: The activation signaling includes an MDT configuration message; and The MDT configuration message includes an information element that indicates to the radio access network node that slice-specific measurements will be collected and reported.

10. The method according to claim 9, wherein, The MDT configuration message also specifies the area range of the network slice-specific measurement.

11. The method according to claim 10, wherein, The MDT measurement items are collected by the radio access network node only when the UE is located within the area.

12. The method according to claim 10, wherein, The MDT measurements collected by the radio access network node include the data usage of the UE in the network slice within the area.

13. The method according to claim 9, wherein, After the UE collects the MDT measurement items only when the UE is within the area of ​​the network slice, the MDT measurement items are received by the radio access network node from the UE.

14. A method performed by a core network in a wireless network connected to a radio access network node, the core network and the radio access network node being configured to serve a network slice, the method comprising: Send an activation signaling message for minimizing drive test MDT to the wireless access network node, wherein the activation signaling message identifies the network slice; Identify the user equipment (UE) connected to the radio access network node via the network slice using an Active Protocol Data Unit (PDU) session; Receive an MDT report from the radio access network node, the MDT report including MDT measurement items related to the UE, the MDT measurement items being collected by the radio access network node according to the activation signaling; as well as The core network's tracking and collection entity (TCE) performs deployment or performance analysis on the network slices based on the MDT report.

15. A method performed by a wireless terminal, the wireless terminal communicating with a wireless access network node via a network slice in a wireless network, the method comprising: Establish a Protocol Data Unit (PDU) session with the wireless access network node within the network slice; When the wireless terminal is located within the area specified in the minimized drive test MDT configuration of the network slice, area-specific MDT measurements are collected; as well as An MDT report containing the area-specific MDT measurements is sent to the wireless access network node for forwarding to the tracking collection entity (TCE) of the wireless network.

16. The method according to claim 15, wherein, When a network resource shortage is detected in the network slice, the MDT measurement items are collected.

17. The method according to claim 16, wherein, A network resource shortage is detected in the network slice when the following conditions occur: The deletion process of the PDU session is triggered; At the wireless access network node, multi-carrier resource sharing is triggered to allocate network resources to the network slice; The wireless access network node initiates dual connectivity or carrier aggregation with different frequencies and overlapping coverage for the wireless terminal; Initiate resource reallocation at the wireless access network node to use network resources from the shared resource pool and / or the priority resource pool when dedicated or priority network resources at the wireless network access node are unavailable. or The target radio access network node denies access to PDU sessions of wireless terminals in network slice 1 during the handover preparation process.

18. The method of claim 16, wherein: The MDT configuration includes an information element that instructs the radio access network node to collect and report slice-specific measurements.

19. The method according to claim 18, wherein, The area range is specified using a cell identifier in the MDT configuration.

20. The method of claim 15, wherein, The MDT measurements collected by the wireless terminal include the amount of data used by the wireless terminal in the network slices within the area.

21. The wireless access network node, wireless terminal, or core network according to any one of claims 1 to 20, comprising a processor and a memory, wherein, The processor is configured to read computer code from the memory, causing the wireless access network node, wireless terminal, or core network to perform the method according to any one of claims 1 to 20.

22. A computer program product comprising a non-transitory computer-readable program medium having computer code stored thereon, the computer code, when executed by a processor of a wireless terminal, wireless access network node, or core network according to any one of claims 1 to 20, causing the processor to implement the method according to any one of claims 1 to 20.

Images