Cell reselection mechanism interaction

Abstract

A network element of the wireless communication network is communicatively coupled to the user equipment and identifies a list of one or more features provided by the wireless communication network. Each feature on the list is associated with at least one of a service capability of the UE and a service requirement of the user equipment. The network element determines a priority among the one or more features related to cell reselection and assigns cell reselection priorities to the user equipment according to the priority, for example, by indicating the cell reselection priority or feature priorities and corresponding cell reselection mechanisms to the user equipment. The user equipment performs cell reselection by applying the cell reselection mechanism and cell reselection priority in accordance with the instructions of the network element.

Description

Technical Field

[0001] The present disclosure generally relates to a mobile communication network such as a 5G communication network, and more particularly to cell reselection.

Background Art

[0002] Network slicing is a newly introduced feature by the Third Generation Partnership Project (3GPP) in a New Radio (NR) mobile network, also referred to as the fifth generation (5G), for supporting different services using the same underlying mobile infrastructure. The current level of standardization at a general level is given by 3GPP Technical Specification 38.300.

[0003] Network slices can differ either in their service requirements such as ultra-reliable low-latency communication (URLLC) and enhanced mobile broadband (eMBB) or in their tenants providing those services.

[0004] Network slices are uniquely identified via S-NSSAI (Single Network Slice Selection Assistance Information). Current 3GPP specifications enable a user equipment (UE) to be simultaneously connected and served by eight slices corresponding to eight network slices identified by up to eight S-NSSAIs. See 3GPP TS38.300. On the other hand, a cell can support dozens or even hundreds of slices. For example, in current specifications, a tracking area (TA) can support up to 1024 network slices. See 3GPP TS38.423.

[0005] The present disclosure aims to improve cell reselection in a network environment by network slicing and slice-specific cell reselection mechanisms.

Summary of the Invention

[0006] According to a first aspect, a method for cell reselection is provided. The method is performed by a network element of a wireless communication network. The network element is communicatively coupled to a user device, UE. The network element identifies a list of one or more functions provided by the wireless communication network. Each function on the list is associated with at least one of the UE's service capabilities and the UE's service requests. The network element determines the priority among the identified functions related to cell reselection and assigns the UE a cell reselection priority according to the priority.

[0007] In some embodiments, assigning a cell reselection priority to a UE involves instructing the UE on a cell reselection priority and a priority among identified functions related to cell reselection.

[0008] In some embodiments, assigning a cell reselection priority to the UE includes determining, for each identified function, single network slice selection assistance information, S-NSSAI, and the corresponding network slice access layer group, NSAG, for the slice-specific cell reselection mechanism, and instructing the UE on a cell reselection priority corresponding to the determined priority among the identified functions related to cell reselection.

[0009] In some embodiments, cell reselection priorities are expressed in the form of NSAG priorities or as slice-specific cell reselection priorities mapped to the corresponding NSAG.

[0010] In some embodiments, the network element transmits authorized network slice selection support information, including at least one or more S-NSSAI associated with identified functions, to the UE.

[0011] In some embodiments, the network element transmits configured network slice selection support information, which includes at least one or more S-NSSAI associated with identified functions, and configured NSSAI to the UE.

[0012] In some embodiments, identifying a list of features includes identifying a list of features based on a list of features of interest received from the UE.

[0013] In some embodiments, the functionality includes at least one of slice-specific cell reselection, multicast broadcast services, high-speed data network-specific features, and sidelink communication.

[0014] In some embodiments, the function related to cell reselection is a function having a corresponding cell reselection mechanism.

[0015] In some embodiments, assigning a cell reselection priority to a UE includes signaling the UE with a cell reselection priority according to the priority order, either by system information broadcasting or dedicated signaling.

[0016] In a further embodiment, a network element of a wireless communication network is provided. The network element is communicatively coupled to a user device, UE, and identifies a list of one or more functions provided by the wireless communication network, each function on the list being configured to identify, relating to at least one of the UE's service capabilities and the UE's service requests, to determine priority among the identified functions relating to cell reselection, and to assign a cell reselection priority to the UE according to the priority.

[0017] In some embodiments, a network element is configured to assign a cell reselection priority to the UE by causing it to instruct the UE on at least one of the cell reselection priority and the priority among the identified functions related to cell reselection.

[0018] In some embodiments, the network element is configured to determine, for each identified function, a single network slice selection support information, S-NSSAI, and the corresponding network slice access layer group, NSAG, for a slice-specific cell reselection mechanism, and to instruct the UE on the cell reselection priority corresponding to the determined priority among the identified functions related to cell reselection.

[0019] In some embodiments, cell reselection priorities are expressed in the form of NSAG priorities or as slice-specific cell reselection priorities mapped to the corresponding NSAG.

[0020] In some embodiments, the network element is configured to transmit authorized network slice selection assistance information, which includes at least one or more S-NSSAI associated with identified functions, to the UE.

[0021] In some embodiments, the network element is configured to transmit configured network slice selection assistance information, which includes at least one or more S-NSSAI associated with identified functions, to the UE.

[0022] In some embodiments, the network element is configured to identify a list of features based on a list of features of interest received from the UE.

[0023] In some embodiments, the functions include at least one of slice-specific cell reselection, multicast broadcast service, high-speed data network-specific, and sidelink communication.

[0024] In some embodiments, the function related to cell reselection is a function having a corresponding cell reselection mechanism.

[0025] In some embodiments, the network element is configured to assign the cell reselection priority of the UE by causing the UE to be signaled with the cell reselection priority according to the priority by system information broadcast or dedicated signaling.

[0026] According to another aspect, a method for cell reselection is provided. The method is executed by a user equipment, UE, communicatively coupled to a network element of a wireless communication network. The UE receives from the network element at least one of the cell reselection priority of one or more functions related to cell reselection and the priority among the identified functions related to cell reselection, and each function is provided by the wireless communication network and is related to at least one of the service capabilities of the UE and the service requirements of the UE. The UE applies one of the plurality of cell reselection mechanisms based on at least one of the cell reselection priority and the priority.

[0027] In some embodiments, the function related to cell reselection is a function having a corresponding cell reselection mechanism.

[0028] In some embodiments, receiving at least one of the cell reselection priority and the priority from the network element includes receiving the cell reselection priority or the priority by system information broadcast or dedicated signaling..

[0029] According to yet a further aspect, there is provided a user equipment, UE, communicatively coupled to a network element of a wireless communication network. The UE is configured to receive from the network element of the wireless communication network at least one of a cell reselection priority of one or more functions related to cell reselection and a priority among functions related to cell reselection, each function being provided by the wireless communication network and related to at least one of the UE's service capabilities and the UE's service requirements. The UE is further configured to apply one of a plurality of cell reselection mechanisms based on at least one of the cell reselection priority and the priority.

[0030] In some embodiments, the function related to cell reselection is a function having a corresponding cell reselection mechanism.

[0031] In some embodiments, the UE is configured to receive at least one of the cell reselection priority and the priority by being caused to receive the cell reselection priority or the priority by system information broadcast or dedicated signaling.

[0032] According to another aspect, there is provided a method for cell reselection performed by a user equipment, UE. The UE is communicatively coupled to a network element of a wireless communication network. The UE receives from the network element a cell reselection priority corresponding to a determined priority among one or more functions related to cell reselection, the cell reselection priority including a network slice access layer group, NSAG, priority or a slice-specific cell reselection priority mapped to each corresponding NSAG, each function being provided by the wireless communication network and related to at least one of the UE's service capabilities and the UE's service requirements. The UE applies a slice-specific cell reselection mechanism based on the NSAG priority or based on the slice-specific cell reselection priority.

[0033] In some embodiments, the UE receives authorized network slice selection support information, authorized NSSAI, from a network element, which includes at least one single network slice selection support information, S-NSSAI, associated with a function for cell reselection.

[0034] In some embodiments, the UE receives configured network slice selection support information, configured NSSAI, from a network element, which includes at least one single network slice selection support information, S-NSSAI, associated with a function for cell reselection.

[0035] In some embodiments, the functionality includes at least one of slice-specific cell reselection, multicast broadcast services, high-speed data network-specific features, and sidelink communication.

[0036] In some embodiments, the function related to cell reselection is a function having a corresponding cell reselection mechanism.

[0037] In some embodiments, receiving cell reselection priority from a network element includes receiving cell reselection priority by system information broadcast or dedicated signaling.

[0038] In a further embodiment, a user device, UE, is provided that is communicatively coupled to a network element of a wireless communication network. The UE is configured to receive from the network element a cell reselection priority corresponding to a determined priority among one or more functions related to cell reselection, the cell reselection priority including a network slice access layer group, an NSAG priority, or a slice-specific cell reselection priority mapped to the respective corresponding NSAG, each of which is provided by the wireless communication network and is related to at least one of the UE's service capability and the UE's service request. The UE is configured to apply a slice-specific cell reselection mechanism based on the NSAG priority or based on the slice-specific cell reselection priority.

[0039] In some embodiments, the UE is configured to receive authorized network slice selection assistance information, authorized NSSAI, from a network element, which includes at least one single network slice selection assistance information, S-NSSAI, associated with a function for cell reselection.

[0040] In some embodiments, the UE is configured to receive configured network slice selection assistance information, configured NSSAI, from a network element, which includes at least one single network slice selection assistance information, S-NSSAI, associated with a function for cell reselection.

[0041] In some embodiments, the functionality includes at least one of slice-specific cell reselection, multicast broadcast services, high-speed data network-specific features, and sidelink communication.

[0042] In some embodiments, the UE is configured to receive cell reselection priority by being made to receive it through system information broadcasting or dedicated signaling.

[0043] In a further embodiment, a method for slice-based cell reselection performed by a user device is presented. The user device is communicatively coupled to a network element of a wireless communication network. The user device receives at least one network slice access layer group, an NSAG, and priority information for at least one NSAG. Based on the at least one NSAG and the priority information for at least one NSAG, the user device derives a reselection priority for slice-based cell reselection according to a predetermined scheme (e.g., TS38.304 Section 5.2.4.11). The user device does not modify the reselection priority due to other factors of cell reselection. That is, the user device applies the slice-based cell reselection mechanism even if one or more other factors of cell reselection other than slice-based cell reselection trigger cell reselection.

[0044] In some embodiments, the priority information for at least one NSAG includes a priority for each NSAG and at least one of the priorities of one or more corresponding frequencies mapped to at least one NSAG.

[0045] In a further embodiment, a user device supporting slice-based cell reselection is presented. The user device is communicably coupled to a network element of a wireless communication network and comprises a processor and a memory having instructions, which, when executed by the processor, cause the user device to receive at least one network slice access layer group, NSAGs, and priority information of at least one NSAG, and to derive a reselection priority for slice-based cell reselection according to a predetermined scheme based on at least one NSAG and the priority information of at least one NSAG, and not to modify the reselection priority due to other factors of cell reselection. In other words, the user device applies the slice-based cell reselection mechanism even if one or more other factors of cell reselection other than slice-based cell reselection trigger cell reselection.

[0046] In some embodiments, the priority information for at least one NSAG includes a priority for each NSAG and at least one of the priorities of one or more corresponding frequencies mapped to at least one NSAG.

[0047] In a further embodiment, the computer program, when executed by at least one processor, includes instructions that perform any one of the method embodiments and embodiments described above.

[0048] In a further embodiment, the computer-readable storage medium stores instructions that, when executed by at least one processor, cause the computer to execute any one of the aforementioned method embodiments and embodiments.

[0049] Various embodiments will be described in more detail below with reference to the attached drawings. [Brief explanation of the drawing]

[0050] [Figure 1] This diagram visualizes the slice-based cell reselection procedure. [Figure 2] This is a schematic diagram of an exemplary communication system comprising a base station and multiple communication devices. [Figure 3] This is a schematic diagram of an example mobile communication device. [Figure 4] This is a schematic diagram of an exemplary control device. [Figure 5] This is a flowchart of the cell reselection procedure at a general level as described herein. [Figure 6] This is a diagram illustrating a typical message sequence representation of a cell reselection procedure as described herein. [Figure 7A] This figure shows a slice-based cell reselection procedure based on S-NSSAI and / or NSAG priorities related to one or more functions of a wireless communication network. [Figure 7B] This figure shows a slice-based cell reselection procedure based on S-NSSAI and / or NSAG priorities related to one or more functions of a wireless communication network. [Figure 8A] This figure shows a cell reselection procedure based on a priority list of one or more functions provided by a wireless communication network. [Figure 8B] This figure shows a cell reselection procedure based on a priority list of one or more functions provided by a wireless communication network. [Modes for carrying out the invention]

[0051] As mentioned above, network slices are identified by S-NSSAI. S-NSSAI may include both Slice Service Type (SST) and Slice Differential (SD) fields, with a total length of 32 bits, or it may include only the SST field portion, in which case the S-NSSAI is 8 bits long. See 3GPP TS23.501 and 3GPP TS23.003. The SST field can have standard and non-standard values. Values ​​0 to 127 belong to the standard SST range. For example, an SST value of 1 may indicate that the slice is suitable for 5G eMBB processing, a value of 2 may indicate that it is suitable for URLLC handling, and so on. SD is operator-defined only.

[0052] TS23.501 defines several types of NSSAI. Authorized NSSAI are, for example, NSSAI provided by the Serving PLMN during the registration procedure, which indicate the S-NSSAI value that the UE can use in the Serving PLMN for the current registration area. Configured NSSAI are provisioned in the UE applicable to one or more PLMNs. Pending NSSAI are provided by the Serving PLMN during the registration procedure, which indicate S-NSSAI for which network slice-specific authentication and authorization procedures are pending. Requested NSSAI are provided by the UE to the Serving PLMN during registration. Enrolled S-NSSAI are based on subscriber information that the UE has enrolled in for use in the PLMN.

[0053] A UE in an RRC idle or RRC inactive state performs cell reselection to determine which cell the UE should camp on to. Cell reselection is based on radio measurement values ​​and frequency priority. See 3GPP TS38.304. The UE may receive general frequency priority in system information such as a System Information Block (SIB) and UE-specific priority in an RRC release message. The validity of UE-specific priority may be limited by timers.

[0054] According to 3GPP TS38.300, cell reselection criteria include measurements of the serving cell and neighboring cells. Intra-frequency reselection is based on cell ranking. Inter-frequency reselection is based on absolute priority, where the UE attempts to camp on the highest available priority frequency. Neighboring Cell Lists (NCLs) may be provided by the serving cell to handle specific cases of intra-frequency and inter-frequency neighboring cells. Exclusion lists may be provided to prevent the UE from reselecting specific intra-frequency and inter-frequency neighboring cells. Allow lists may be provided to request the UE to reselect only specific intra-frequency and inter-frequency neighboring cells. Cell reselection may be velocity-dependent. Service-specific prioritization is possible.

[0055] Until 3GPP Specification Release 17, cell reselection was ignorant of network slices. However, the most appropriate cell to be selected by the UE may depend on the slice the UE intends to use. Therefore, in Release 17, the ability to select a slice-based cell reselection is introduced. Thus, slice-specific cell reselection information may be provided to facilitate the UE reselecting a cell that supports a particular slice. This slice-specific cell reselection mechanism allows the UE to reselect a cell on a frequency preferred by the network operator based on the network slice most important to the UE, based on slice-specific cell reselection priorities, but it does not guarantee that the UE will reselect a cell that supports an permitted network slice or the most important network slice. If the UE reselects a cell that does not support an permitted network slice, the network can still redirect or hand over the UE (which is in an RRC connected state) to a cell more suitable for the UE (for example, with respect to the network slice).

[0056] In addition, the concept of slice groups (NSAG-Network Slice AS Groups) is introduced to enable signaling optimization (particularly with respect to broadcasts) and to facilitate security when publishing S-NSSAI. UEs receive the mapping of slices to NSAGs using Non-Access Layer (NAS) signaling. UEs may also receive per-NSAG priorities (NSAG-specific cell reselection priorities). Broadcasting of priority information for slice-specific cell reselection (e.g., slice-specific reselection priority) is performed per NSAG by radio access network (RAN) nodes such as gNBs (see nsag-CellReselectionPriority, 3GPP TS38.304 dependent sections 5.2.4.1 and 5.2.4.11).

[0057] An exemplary slice-specific cell reselection procedure is shown in Figure 1. At 11, the UE400 receives a general NSAG and corresponding priority (different from cell reselection priority) from a network such as the AMF500 via NAS messages. At 12, the UE400 receives NSAG-specific cell reselection priority (frequency band priority per NSAG) from the RAN (e.g., gNB450) either by broadcast (a new SIB may be defined for this purpose) or by dedicated signaling, such as an RRC release message that transitions the UE400 from RRC connection to RRC idle. Cell reselection information received via dedicated signaling, such as an RRC release message, has priority over reselection information in the SIB. The gNB450, which manages the cells, may at 13 broadcast either a per-NSAG, per-bandwidth list of allowed cells or a per-NSAG list of excluded cells to support cell reselection in the boundary area of ​​the tracking area. Cells that are in the allowed list or not in the excluded list are assumed to support a given NSAG, provided that a list exists for that given NSAG and bandwidth. The UE400 prioritizes the frequency bandwidth using NSAG-specific cell reselection priorities (see TS38.304 for further details on how the UE uses priorities), and as a result, still takes into account the cell reselection criteria described above, to either camp on to the current serving cell or reselect another cell.

[0058] Other cell reselection mechanisms are defined in other Release 17 work items, which will hereafter also be referred to as function-specific cell reselection mechanisms. See TS38.304. One of these further cell reselection mechanisms relates to High-Speed ​​Data Networks (HSDN). When an HSDN-enabled UE is in a high-mobility state, the UE considers HSDN cells to have the highest priority (i.e., higher than any other network-configured priority). When an HSDN-enabled UE is not in a high-mobility state, the UE always considers HSDN cells to have the lowest priority (i.e., lower than any other network-configured priority).

[0059] Further cell reselection mechanisms relate to multicast broadcast services (MBS). If an MBS-enabled UE receives or is interested in receiving an MBS session and can receive this MBS session by camping on the frequency on which the MBS session is provided, the UE may consider that particular frequency as the highest priority during the MBS session, as specified in TS38.300. As long as an MBS-enabled UE receives or is interested in receiving an MBS session, the UE may consider cell reselection candidate frequencies on which the UE cannot receive the MBS session as the lowest priority during the MBS broadcast session (see TS38.300).

[0060] Further cell reselection mechanisms relate to sidelink communication from pre-release 17. If a UE is configured to perform both NR sidelink communication and V2X (vehicle-to-vehicle) sidelink communication, the UE may consider the frequency that provides both the NR sidelink communication configuration and the V2X sidelink communication configuration as the highest priority. If a UE is configured to perform NR sidelink communication but not V2X communication, the UE may consider the frequency that provides the NR sidelink communication configuration as the highest priority. If a UE is configured to perform V2X sidelink communication but not NR sidelink communication, the UE may consider the frequency that provides the V2X sidelink communication configuration as the highest priority.

[0061] Currently, since broadcast services can be received by all authorized UEs within a given geographical area, there is no way for a UE to determine which slice will provide a broadcast session, even if it is not included in the User Service Description (USD) of the MBS session. It should be noted that this is different from multicast services, where the UE must participate in the multicast session and therefore receive the relevant S-NSSAI within the USD. For this reason, currently, a UE does not need to be configured with the S-NSSAI that the UE uses for broadcast services within an authorized NSSAI.

[0062] In the case of slice-specific cell reselection, the UE derives frequency reselection priorities based on the NSAG and their corresponding cell reselection priorities. MBS allows the UE to consider MBS frequencies as the highest priority for enhancing broadcast service continuity. Similarly, HSDN allows the UE to consider certain frequencies as the highest priority. This also applies to sidelink communications.

[0063] Therefore, when the UE intends to use, for example, slice-specific cell reselection in addition to function-specific cell reselection mechanisms such as MBS frequency prioritization, the UE behavior is currently non-specific. More specifically, there are several possible interpretations of what it means for an MBS frequency to be "considered the highest priority." For example, does MBS take precedence over or in addition to slice-specific priorities? Is an MBS frequency considered the highest priority frequency among frequencies that do not map to any slice-specific priority (i.e., frequencies with slice-specific priorities always have a higher priority than MBS)? Is an MBS frequency considered the highest priority frequency (i.e., takes precedence over frequencies that also have slice-specific priorities)? Is an MBS frequency considered the highest priority frequency among slices that allow MBS frequencies, and is NSAG-specific priority within those slices used to select the best frequency to camp on?

[0064] Therefore, the purpose of this disclosure is to provide interactions between different cell reselection mechanisms available in Release 17 and potentially future cell reselection mechanisms.

[0065] Before describing these examples in detail, we will briefly explain the specific general principles of wireless communication systems and mobile communication devices with reference to Figures 2-4 to help understand the underlying technologies of the examples described.

[0066] In a wireless communication system 100, such as that shown in Figure 2, mobile communication devices, user devices, and user equipment (UEs) 102, 104, and 105 are provided with wireless access via at least one base station (e.g., next-generation NB, gNB), similar wireless transmit and / or receive nodes, or network nodes. The base station may be controlled or assisted by at least one suitable controller device to enable its operation and management of the mobile communication devices communicating with the base station. The controller device may be located within a radio access network (RAN) (e.g., wireless communication system 100) or a core network (CN) (not shown), and may be implemented as a single central device, or its functions may be distributed across several devices. The controller device may be part of the base station and / or may be provided by a separate entity such as a radio network controller (RNC) or central unit (CU) that typically runs higher network layers such as Layer 3 protocols and / or radio resource control (RRC) protocols. In Figure 2, controllers 108 and 109 for controlling the respective macro-level base stations 106 and 107 are shown. The base station's control unit can interconnect with other control entities. Typically, the control unit is provided with memory functionality and at least one data processor. The control unit and its functions may be distributed among multiple control units. In some systems, the control unit may be provided additionally or alternatively in the RNC.

[0067] In Figure 2, base stations 106 and 107 are shown as being connected to a wider communication network 113 via gateway 112. Further gateway functionality may be provided for connecting to other networks.

[0068] Where used herein, the term “base station” has the full scope of its ordinary meaning and includes at least a wireless communications station installed in a fixed location and used to communicate as part of a wireless telephone system or radio system. The communication area (or coverage area) of a base station may be referred to as a “cell.” Base stations and UEs can be configured to communicate over a transmission medium using any of the various radio access technologies (RATs), also referred to as wireless communications technologies, or the telecommunications standards described below. As shown in Figure 2, one of the base stations may act as a “serving cell” of a UE, and the UE may also receive (and possibly be within its communication range of) one or more other cells (which may be provided by the base station and / or any other base station), which may be referred to as “neighboring cells.” As mentioned above, a base station may include multiple network nodes, such as an upper controller node running an upper network layer, such as Layer 3 / RRC, and one or more lower nodes, such as distributed units (DUs), typically running lower network layers, such as the physical layer (Layer 1, L1) and Layer 2 (L2). It should be noted that these multiple units may be located in the same geographical location, or they may be geographically separated by a certain distance.

[0069] Smaller base stations 116, 118, and 120 may also be connected to network 113, for example, by a separate gateway function and / or via a controller of a macro-level station. Base stations 116, 118, and 120 may be pico or femto-level base stations, etc. In this example, stations 116 and 118 are connected via gateway 111, while station 120 is connected via controller device 108. In some embodiments, smaller stations may not be provided. Smaller base stations 116, 118, and 120 may be part of a second network, such as a wireless local area network (WLAN), and may be WLAN access points (APs). Communication devices 102, 104, and 105 may access the communication system based on various access techniques, such as code division multiple access (CDMA) or wideband CDMA (WCDMA). Other non-limiting examples include time-division multiple access (TDMA), frequency-division multiple access (FDMA), and various forms thereof such as interleaved frequency-division multiple access (IFDMA), single-carrier frequency-division multiple access (SC-FDMA), and orthogonal frequency-division multiple access (OFDMA), as well as spatial-division multiple access (SDMA).

[0070] An example of a wireless communication system is the architecture standardized by the Third Generation Partnership Project (3GPP). The latest 3GPP-based developments are often referred to as the Long-Term Evolution of Universal Mobile Communications System (UMTS) Radio Access Technology (LTE). Various development stages of 3GPP specifications are referred to as releases. More recent developments of LTE are often referred to as LTE Advanced (LTE-A). LTE (or LTE-A) utilizes a radio-mobile architecture known as the Evolutionary Universal Terrestrial Radio Access Network (E-UTRAN) and a core network known as the Evolutionary Packet Core (EPC). Base stations in such systems, known as Evolutionary or Extended Node B (eNB), provide E-UTRAN functions such as user-plane packet data convergence / radio link control / medium access control / physical layer protocol (PDCP / RLC / MAC / PHY) and control plane radio resource control (RRC) protocol termination for communication devices. Other examples of radio access systems include those provided by base stations in systems based on technologies such as WLAN and / or Global Interoperability Microwave Access (WiMAX). A base station can provide coverage for an entire cell or a smaller wireless service area. Core network elements include a mobility management entity (MME), a serving gateway (e.g., S-GW), and a packet gateway (P-GW).

[0071] An example of a suitable communication system is the 5G or NR concept. The network architecture of NR may be similar to that of LTE-A. Base stations in an NR system may be known as next-generation node B (gNB). Changes to the network architecture may depend on the need to support various radio technologies, more granular quality of service (QoS) support, and several on-demand requirements for QoS to support user-centric quality of experience (QoE). Network-aware services and applications, as well as service and application-aware networks, can also bring about changes to the architecture. These relate to information-oriented network (ICN) and user-oriented content delivery network (UC-CDN) methodologies. NR can use more base stations or nodes (the so-called small cell concept) than LTE, including multi-input multi-output (MIMO) antennas and macrosites working with smaller stations, and may also utilize various radio technologies for better coverage and enhanced data rates.

[0072] Future networks may utilize Network Function Virtualization (NFV), a network architecture concept that proposes virtualizing network node functions into "building blocks," or entities that are operationally connected or can be linked together to provide services. A virtualized network function (VNF) may include one or more virtual machines that run computer program code using standard or common types of servers instead of customized hardware. Cloud computing or data storage may also be utilized. In wireless communication, this may mean that node operations run within a server, host, or node that is at least partially coupled to a remote radio head. Node operations can also be distributed across multiple servers, nodes, or hosts. It should also be understood that the distribution of work between core network operations and base station operations may differ from, or may not even exist, that of LTE.

[0073] An exemplary 5G core network (CN) includes functional entities. The CN is connected to the UE via a radio access network (RAN). A user plane function (UPF), whose role is called a PDU session anchor (PSA), may be responsible for exchanging frames between the data network (DN) and the tunnel established over 5G for the UE to exchange traffic with the DN.

[0074] The UPF is controlled by a Session Management Function (SMF) that receives policies from a Policy Control Function (PCF). The CN may also include Access and Mobility Functions (AMF).

[0075] Here, possible (mobile) communication devices 200 will be described in more detail with reference to Figure 3, which shows a schematic partial cross-sectional view. Such mobile communication devices 200 are often referred to as user equipment (UE), user devices, or terminal devices. A suitable mobile communication device 200 may be provided by any device capable of transmitting and receiving radio signals. Non-limiting examples include mobile stations (MS) or mobile devices such as mobile phones or things known as "smartphones," computers equipped with wireless interface cards or other wireless interface equipment (e.g., USB dongles), personal digital assistants (PDAs) or tablets equipped with wireless communication capabilities, or any combination thereof. Mobile communication devices 200 can provide data communications for carrying communications such as voice, email, text messages, and multimedia. Thus, a number of services can be supplied and provided to users through these communication devices. Non-limiting examples of these services include two-way or multi-way calls, data communications or multimedia services, or simply access to data communications network systems such as the Internet. Broadcast or multicast data may also be provided to users. Non-exclusive examples of content include downloads, television and radio programs, videos, advertisements, various warnings, and other information.

[0076] In industrial applications, the communication device may be a modem integrated into an industrial actuator (e.g., a robotic arm) and / or a modem acting as an Ethernet hub that acts as a connection point for one or more connected Ethernet devices (whether wired or wireless).

[0077] The communication device 200 typically includes at least one data processing entity 201, at least one memory 202, and other possible components 203 for use in software and hardware-assisted execution of tasks designed for the wireless device to perform, including control of access to and communication with access systems and other communication devices. Data processing, storage, and other related control devices may be located on a suitable circuit board and / or within a chipset 204. The user can control the operation of the communication device 200 by using a suitable user interface such as a keypad 205, voice commands, a touch-sensitive screen or pad, or a combination thereof. A display 208, speaker, and microphone may also be provided. Furthermore, the communication device 200 may include suitable connectors (either wired or wireless) for connecting to other devices and / or external accessories such as hands-free devices to the wireless communication device.

[0078] The communication device 200 can receive signals over an air interface or radio interface 207 via a suitable receiving device, and can transmit signals via a suitable transmitting device. In Figure 3, a transceiver device is schematically designated by block 206. The transceiver device 206 can be provided, for example, by using radio components and associated antenna configurations. The antenna configuration may be located outside or inside the communication device 200.

[0079] The communication device 200 may also, or alternatively, be configured to communicate using, as desired, one or more global satellite navigation systems (GNSS such as GPS or GLONASS), one or more mobile television broadcasting standards (e.g., ATSC-M / H or DVB-H), and / or any other wireless communication protocols. Other combinations of wireless communication standards (including three or more wireless communication standards) are also possible.

[0080] Generally, the communication device 200 shown in Figure 3 includes a set of components configured to perform a core function. For example, this set of components may be implemented as a system-on-a-chip (SoC), which may include parts for various purposes. Alternatively, this set of components may be implemented as separate components or groups of components for various purposes. The set of components may be coupled (communicatively) to various other circuits of the communication device 200 (e.g., directly or indirectly).

[0081] The communication device 200 may include at least one antenna that communicates with a transmitter and a receiver (e.g., a transceiver device 206). Alternatively, the transmitting antenna and the receiving antenna may be separate. The communication device 200 may also include a processor (e.g., at least one data processing entity 201) configured to provide signals to the transmitter, receive signals from the receiver, and control the functions of the communication device 200. The processor may be configured to control the functions of the transmitter and receiver by providing control signaling to the transmitter and receiver via electrical leads. Similarly, the processor may be configured to control other elements of the communication device 200 by providing control signaling via electrical leads that connect the processor to other elements such as a display (e.g., a display 208) or memory (e.g., at least one memory 202). A processor may be embodied in various forms, including, for example, a circuit, at least one processing core, one or more microprocessors accompanied by a digital signal processor, one or more processors without a digital signal processor, one or more coprocessors, one or more multicore processors, one or more controllers, processing circuits, one or more computers, various other processing elements including integrated circuits such as application-specific integrated circuits (ASICs) and field-programmable gate arrays (FPGAs), or any combination thereof. Thus, in some examples, a processor may include multiple processors or processing cores.

[0082] The communication device 200 may operate using one or more air interface standards, communication protocols, modulation types, access types, etc. The signals transmitted and received by the processor may include signaling information in accordance with applicable cellular system air interface standards and / or, but not limited to, any number of different wired or wireless networking techniques, including Wi-Fi, WLAN techniques, such as IEEE 802.11, 802.16, 802.3, ADSL, DOCSIS, etc. In addition, these signals may include speech data, user-generated data, user request data, etc.

[0083] For example, the communication device 200 and / or the cellular modem within it may be capable of operating according to various third-generation (3G), fourth-generation (4G), fifth-generation (5G) communication protocols, such as Internet Protocol Multimedia Subsystem (IMS) including Session Initiation Protocol (SIP), or 5G Beyond. For example, the communication device 200 may be capable of operating according to 4G wireless communication protocols such as LTE-A, 5G, and similar wireless communication protocols that may be developed in the future.

[0084] The processor may include circuits for performing the audio / video and logic functions of the communication device 200. For example, the processor may include a digital signal processor device, a microprocessor device, an analog-to-digital converter, a digital-to-analog converter, and the like. The control and signal processing functions of the communication device 200 may be distributed among these devices according to their respective functions. The processor may additionally include an internal voice coder, an internal data modem, and the like. Furthermore, the processor may include functions for running one or more software programs, which may be stored in memory. Generally, the processor and the stored software instructions may be configured to cause the communication device 200 to perform operations. For example, the processor may be capable of running a connectivity program such as a web browser. The connectivity program can enable the communication device 200 to send and receive web content, such as location-based content, according to protocols such as Wireless Application Protocol (WAP) or Hypertext Transfer Protocol (HTTP).

[0085] The communication device 200 may also include a user interface, such as an earphone or speaker, a ringer, a microphone, a display, a user input interface, etc., which can be operably coupled to the processor. The display may include a touch-sensitive display, as mentioned above, where the user can make selections, input values, etc., by touching or making gestures. The processor may also include a user interface circuit configured to control at least some functions of one or more elements of the user interface, such as a speaker, ringer, microphone, display, etc. The processor, and / or a user interface circuit comprising a processor, may be configured to control one or more functions of one or more elements of the user interface through computer program instructions, such as software and / or firmware, stored in memory accessible to the processor, such as volatile memory, non-volatile memory, etc. The communication device 200 may include a battery for powering various circuits associated with the mobile terminal, such as a circuit for providing mechanical vibration as a detectable output. The user input interface may include devices that enable the communication device 200 to receive data, such as a keypad (e.g., keypad 206) and / or other input devices. The keypad may also be a virtual keyboard presented on the display or an externally connected keyboard.

[0086] The communication device 200 may also include one or more mechanisms for sharing and / or acquiring data. For example, the communication device 200 may include a short-range radio frequency (RF) transceiver and / or interlogger, which can therefore share data with and / or acquire data from an electronic device according to RF techniques. The communication device 200 may also include other short-range transceivers such as an infrared (IR) transceiver, a Bluetooth® (BT) transceiver operating using Bluetooth® wireless technology, a wireless universal serial bus (USB) transceiver, a Bluetooth® low-energy transceiver, a ZigBee transceiver, an ANT transceiver, a cellular device-to-device transceiver, a wireless local area link transceiver, and / or any other short-range wireless technology. The communication device 200, and more specifically, the short-range transceivers, may be capable of sending and receiving data from electronic devices within the vicinity of the device, for example, within 10 meters. The communication device 200, including a Wi-Fi or WLAN modem, may also be capable of sending and receiving data from electronic devices in accordance with various wireless networking techniques, including WLAN techniques such as 6LoWPAN, Wi-Fi, Wi-Fi Low Power, IEEE 802.11 techniques, IEEE 802.15 techniques, and IEEE 802.16 techniques.

[0087] The communication device 200 may include memory such as one or more subscriber identification modules (SIMs), one or more general-purpose subscriber identification modules (USIMs), one or more removable user identification modules (R-UIMs), one or more embedded general-purpose integrated circuit cards (eUICCs), one or more general-purpose integrated circuit cards (UICCs), etc., which can store information elements related to a mobile subscriber. In addition, the communication device 200 may include other removable and / or fixed memory. The communication device 200 may also include volatile memory and / or non-volatile memory. For example, volatile memory may include random access memory (RAM) including dynamic and / or static RAM, on-chip or off-chip cache memory, etc. Non-volatile memory, which may be embedded and / or removable, may include, for example, read-only memory, flash memory, magnetic storage devices such as hard disks, floppy disk drives, magnetic tapes, optical disk drives and / or media, non-volatile random access memory (NVRAM), etc. Like volatile memory, non-volatile memory may include a cache area for temporarily storing data. At least a portion of the volatile and / or non-volatile memory may be incorporated into the processor. The memory may store one or more software programs, instructions, information fragments, data, etc., which can be used by the device to perform the operations disclosed herein.

[0088] The memory may include an identifier, such as an International Mobile Equipment Identity (IMEI) code, that is capable of uniquely identifying the communication device 200. In an exemplary embodiment, the processor may be configured to use computer code stored in the memory to cause the processor to perform the operations disclosed herein.

[0089] Some of the embodiments disclosed herein may be implemented in software, hardware, application logic, or a combination of software, hardware, and application logic. The software, application logic, and / or hardware may reside, for example, on memory, a processor, or an electronic component. In some exemplary embodiments, the application logic, software, or instruction set is maintained on one of a variety of conventional computer-readable media. In the context herein, “computer-readable media” may be any non-temporary medium or means capable of containing, storing, communicating, propagating, or transporting instructions for use by or in cooperation with an instruction execution system, apparatus, or device, such as a computer or data processor circuit. In the example shown in Figure 3, the computer-readable media may include a non-temporary computer-readable storage medium, which may be any medium capable of containing or storing instructions for use by or in cooperation with an instruction execution system, apparatus, or device, such as a computer.

[0090] User equipment (UE) may include wireless or mobile devices, devices having a radio interface for interacting with a RAN (Radio Access Network), smartphones, in-vehicle devices, IoT devices, M2M devices, etc. Such UE or device may comprise at least one processor and at least one memory containing computer program code, the at least one memory and computer program code configured by at least one processor to cause the device to perform at least certain operations, such as making an RRC connection to a RAN. The UE is configured, for example, to generate messages (e.g., including a cell ID) that will be transmitted to the RAN over radio (e.g., to reach a serving cell and communicate with it). The UE can generate, transmit and receive RRC messages containing one or more RRC PDUs (Packet Data Units).

[0091] A UE may have different states (for example, according to sections 42.1 and 4.4 of 3GPP TS38.331V16.5.0 (June 2021), incorporated by reference). For example, when an RRC connection is established, a UE may be in either the RRC connected state or the RRC inactive state.

[0092] In an RRC connection state, the UE can store the AS (Access Layer) context, transfer unicast data to and from the UE, monitor the control channel associated with the shared data channel to determine whether data is scheduled for that data channel, provide channel quality and feedback information, and perform neighbor cell measurements and measurement reports.

[0093] In some embodiments, the communication device 200 (i.e., a UE or user device in the network) comprises a processor (e.g., at least one data processing entity 201) and memory (e.g., at least one memory 202). The memory contains computer program code that causes the communication device 200 to perform processing in a manner described later.

[0094] Figure 4 shows exemplary embodiments of a control device for a communication system to be coupled to and / or controlled by, for example, a base station, an access system station such as an eNB or gNB, a relay node or core network node such as an MME or S-GW or P-GW, or a core network function such as an AMF / SMF, or a server or host. The method may be implemented within a single control device or across two or more control devices. The control device may be integrated with or external to a node or module of the core network or RAN. In some embodiments, the base station comprises a separate control device unit or module. In other embodiments, the control device may be another network element such as an RNC or spectrum controller. In some embodiments, the base station may have such a control device and a control device provided in an RNC. The control device 300 may be configured to provide control over communications in the service area of ​​the system. The control device 300 comprises at least one memory 301, at least one data processing unit 302, 303, and an input / output interface 304. Through the interface, the control device 300 can be coupled to the receiver and transmitter of the base station. The receiver and / or transmitter may be implemented as a wireless front end or a remote wireless head.

[0095] Generally, the control unit 300 has an antenna for transmitting and receiving radio signals. A radio frequency (RF) transceiver module coupled to the antenna receives RF signals from the antenna, converts them to baseband signals, and transmits them to a processor (e.g., at least one data processing unit 302, 303). The RF transceiver also converts the received baseband signals from the processor, converts them to RF signals, and sends them back to the antenna. The processor processes the received baseband signals and invokes various function modules to perform functions within the control unit 300. A memory (e.g., at least one memory 301) stores program instructions and data for controlling the operation of the control unit 300. In the example in Figure 4, the control unit 300 also includes a protocol stack, as well as a set of control function modules and circuits. A PDU session handling circuit handles PDU session establishment and modification procedures. A policy control module constitutes the policy rules of the UE. Configuration and control circuits provide various parameters for configuring and controlling the UE for related functions, including mobility management and session management. Suitable processors include, for example, dedicated processors, digital signal processors (DSPs), multiple microprocessors, one or more microprocessors associated with a DSP core, controllers, microcontrollers, ASICs, FPGA circuits, and other types of integrated circuits (ICs) and / or state machines.

[0096] In some embodiments, the control device 300 (i.e., a base station, a wireless transmit and / or receive point device, or a network node in a network) comprises a processor (e.g., at least one data processing unit 302, 303) and memory (e.g., at least one memory 301). The memory contains computer program code that causes the control device 300 to perform processing in a manner described later with reference to Figure 5 and subsequent figures.

[0097] Referring here to Figure 5, a method and network elements for cell reselection are visualized at a general level. The network elements form part of a wireless communication network and may include multiple sub-components, such as one or more RAN nodes and / or one or more core network nodes. The network elements are communicatively coupled to user equipment, UEs, and their cell reselection procedures will be controlled by the functions of the present invention. The network elements may also be base stations (e.g., gNBs). In 51, the network elements identify a list of one or more functions provided by the wireless communication network, each function on the list relating to at least one of the UE's service capabilities and the UE's service requests. The functions may be services supported and provided by the wireless network on a particular network slice, such as MBS, HSDN, and sidelinks, as will be further described below. The functions may also be slice-specific cell reselection. In embodiments, the network elements determine such functions included in the list for which a corresponding cell reselection mechanism is defined for that purpose in the wireless communication network, for which the UE signals interest and / or has the capability to do so. For example, if the network slicing functionality is not supported by the UE, and the UE may be signaling this through a preceding capability negotiation, the network element may determine that network slicing should not be included in the list of functions. On the other hand, if the UE has registered an MBS session and / or is signaling interest in an MBS session, the network element includes MBS in the list of one or more functions for cell reselection. The network element then determines the priority among the identified functions related to cell reselection in 52. Thus, each identified function corresponds to a cell reselection mechanism, for example, the function MBS corresponds to MBS-specific cell reselection as described above. Thus, the prioritization of functions constitutes the prioritization of associated or related cell reselections.

[0098] The network element then assigns a cell reselection priority to the UE based on priority in 53. The assignment activity or function 53 may include several sub-activities or sub-functions, including sending or signaling to the UE. In some variations, the network element instructs the UE in 54 on a cell reselection priority and at least one of the priorities among the identified functions related to cell reselection. As will be described in more detail below, the priorities among the listed functions related to cell reselection, or in other words, the priorities among the cell reselection mechanisms corresponding to the identified and prioritized functions, can be presented in the form of a sorted list in which the functions listed first are determined to have a higher priority than the functions listed later. Specific examples are further given below with reference to Figures 7A and 7B and Figures 8A and 8B.

[0099] In some variations, the network element determines, for each identified function, a single network slice selection assistance information (S-NSSAI) for the slice-specific cell reselection mechanism, and the corresponding network slice access layer group (NSAG). The network element then, in 55, instructs the UE on the cell reselection priority corresponding to the determined priority among the identified functions related to cell reselection. The cell reselection priority may indicate the priority of radio frequencies mapped to the NSAG, which can instruct the UE on the priority for selecting available cells in the cell reselection procedure. More specifically, in 55, the network element indicates the cell reselection priority in the form of an NSAG priority, or as a slice-specific cell reselection priority for frequencies mapped to the corresponding NSAG. The network element may also transmit to the UE an authorized NSSAI or configured NSSAI having at least one or more of the determined S-NSSAIs associated with the identified function. Generally, the information shown to the UE by the network element to control the UE's cell reselection behavior may also be shown hereafter as cell reselection configuration information.

[0100] Figure 6 is a further presentation of a cell reselection procedure according to the method of the present invention. The method may be performed by a UE 400 which is communicatively coupled to a first cell 401 of a wireless communication network, i.e., is active, inactive, or idle. In another view, the method may also be performed by one or more network elements of the wireless communication network. The network side, i.e., a network element of the wireless communication network such as a gNB (more specifically, a node of the gNB such as a central unit CU), transmits cell reselection configuration information to the UE 400. The UE 400, now located in, connected to, or camped on to the first cell 401 provided by the network element, receives the cell reselection configuration information from the network element of the wireless communication network at 403.

[0101] Cell reselection configuration information may include, among other things, network slice selection assistance information (NSSAI) related to one or more functions such as the UE's service capabilities and / or services provided by the wireless communication network, and / or indicating the priority of multiple cell reselection mechanisms corresponding to the functions. Cell reselection configuration information may include various information that controls and prioritizes the cell reselection behavior of the UE400. To control the UE400 to apply slice-specific cell reselection, cell reselection information includes network slice selection assistance information (NSSAI). To control the UE400 to apply one cell reselection mechanism from multiple cell reselection mechanisms corresponding to services or functions provided by network slices of a wireless communication network, such as multicast broadcast services (MBS), high-speed data networks (HSDN), and / or sidelink communications, cell reselection configuration information may indicate one or more functions and the priority of the corresponding cell reselection mechanism. Both NSSAI and cell reselection mechanism prioritization options control the UE to use, for example, a slice-specific cell reselection mechanism, even if the UE also receives MBS / HSDN / sidelink transmissions and therefore a cell reselection mechanism corresponding to such transmissions could also be applied.

[0102] Before signaling cell reselection priorities to the UE400, network elements identify features to consider for prioritization, as already mentioned above. For example, the UE400 may indicate prior capability and / or service interests to the network, such as MBS support. Therefore, the UE400 may pre-send a list of features of interest to network elements to facilitate the identification and prioritization of features and corresponding cell reselection mechanisms. The network elements can then identify slice-specific cell reselection and MBS as features to be prioritized and determine the priority of these two features and / or the priority between them. Based on the priority and / or priority, the UE400 is instructed to apply one of the cell reselection mechanisms, such as slice-specific cell reselection rather than MBS-specific cell reselection, and reselects the cell based on the cell reselection priority assigned or provided by the network elements.

[0103] Therefore, in embodiments, the cell reselection configuration information may include further information such as cell reselection priorities, including frequency prioritization-related information, such as a list of frequency-mapped NSAGs and corresponding cell reselection priorities for frequencies, lists such as allowed lists, excluded lists, neighboring cell lists, and service-specific prioritization information. In some embodiments, the mapping between NSAGs and frequencies is provided along with the corresponding cell reselection priorities for frequencies, while in other embodiments, the NSAG-frequency mapping is provided at the top level of the function-related S-NSSAI as an allowed or configured NSSAI, but the cell reselection configuration information does not include any priority of frequencies mapped to the NSAGs. In such embodiments, the UE400 is enabled to reselect cells by slice-specific cell reselection based on NSAG-specific priorities and function-related S-NSSAI provided as an allowed or configured NSSAI.

[0104] Generally, cell reselection configuration information, such as cell reselection priority or priority between functions / cell reselection mechanisms, may be transmitted in a single message or distributed across multiple messages. These messages may include NAS and AS / RAN messages. For example, part of the cell reselection configuration information may be transmitted by the core network in one or more NAS messages, while another part of the cell reselection configuration information may be transmitted by one or more network elements of the wireless access network of the wireless communication network. The cell reselection information may be broadcast to all UEs in cell 401 and / or transmitted by dedicated signaling in RRC messages, such as an RRC release message that transitions a UE from an RRC connection to, for example, an RRC idle state. Thus, the cell reselection information may be transmitted periodically or on demand, for example, in response to a request from a UE. The cell reselection information portion may be transmitted in the course of a specific procedure specified by the 3GPP technical specification, such as a registration request with the requested NSSAI and a registration procedure that includes an authorized NSSAI (indicating an S-NSSAI corresponding to a function requested or supported by the UE) or a configured NSSAI (indicating an S-NSSAI corresponding to a function requested or supported by the UE). The cell reselection information provided to the UE400 may reflect the UE's capabilities and needs, such as its ability or interest in consuming functions to receive MBS transmissions.

[0105] After receiving cell reselection configuration information indicating cell reselection priority, at 404, UE400 applies one cell reselection mechanism from among several cell reselection mechanisms, i.e., based on the priority of NSSAI or multiple cell reselection mechanisms as communicated by the cell reselection configuration information. Thus, UE400 determines which of the multiple cell reselection mechanisms should be applied to determine whether to camp on 405 to the current first cell 401 or reselect 406 to another second cell 402, based on the given cell reselection configuration information and, if applicable, its own capabilities and current service demands. Note that the second cell 402 may belong to the same gNB or CU controlling the first cell 401, or to a different gNB controlling the first cell 401.

[0106] Therefore, by prioritizing the functions supported by wireless communication and determining slice-specific cell reselection priorities associated with the UE, the UE is also enabled to perform cell reselection to consume functions such as MBS by using a slice-based cell reselection mechanism, as opposed to using a cell reselection mechanism specific to a particular function. In other words, when the UE is normally in a camping state, if the UE supports slice-based cell reselection and receives NSAGs and their priorities from the NAS, the UE shall derive reselection priorities in accordance with TS38.304 Section 5.2.4.11 and shall not modify reselection priorities due to other factors (e.g., MBS frequency prioritization). That is, the user device applies the slice-based cell reselection mechanism even if one or more other factors of cell reselection other than slice-based cell reselection trigger cell reselection. In this regard, as described above, it is up to the network to ensure the prioritization of services (e.g., MBS) when NSAG priorities are used.

[0107] Figures 7A and 7B visualize more specific variations of cell reselection by the method described herein. More specifically, Figures 7A and 7B relate to a variation in which a network element provides one or more NSSAIs indicating one or more cells that provide multicast broadcast service transmission, high-speed data network transmission, or sidelink communication. This allows the UE to control the UE to utilize slice-specific cell reselection instead of applying a service or function-related cell reselection mechanism such as MBS-specific cell reselection, but nevertheless allowing the UE400 to reselect cells that provide services such as MBS that the UE400 is interested in or desires to consume. On the other hand, by providing the UE400 with NSSAIs and cell reselection / NSAG priorities, the UE400 can also be controlled to camp on or reselect cells that do not provide services such as MBS for any other reason, such as, for example, because more important services may still be provided in cells that do not provide MBS. Therefore, generally, by provisioning cell reselection configuration information in this manner, the UE400 will apply a slice-specific cell reselection mechanism regardless of any other potentially relevant or ongoing service transmissions, and as a result, the UE400 will prioritize cells for cell reselection based on the NSSAI provided by the network.

[0108] Illustratively, referring to Figure 7A, at 501, the UE400 sends a registration request message to the network via a first cell 401 provided by a RAN element, such as a gNB in ​​this example, for core network elements such as the Wireless Communication Network Access and Mobility Management Function (AMF) 500. The registration request message may contain information about the NSSAI requested by the UE400, reflecting the capabilities and services that the UE400 may potentially intend to use later.

[0109] Next, in 502, the network includes, for example, an S-NSSAI related to an ongoing MBS service as an authorized NSSAI (alternatively, as a configured NSSAI). This is based, for example, on UE capability information indicating that UE400 supports MBS. In other cases, sidelink communication-related S-NSSAI and / or High-Speed ​​Data Network (HSDN)-related S-NSSAI may be included based on UE capability and UE interest in those services. Information to be included by the network in response to a registration request message, such as a request acceptance message described later, may go beyond UE capability information and be based on, for example, an indication that UE400 is about to initiate a service such as a multicast broadcast service (MBS) and / or that there is an ongoing service transmission within a tracking area (TA), such as a broadcast session in cell 402.

[0110] Network elements such as the AMF500 return a registration acceptance message to the UE400 via the first cell 401 at 503. Thus, the UE400 receives the registration acceptance message. As mentioned above, the registration acceptance message carries authorized NSSAIs, including MBS-related S-NSSAIs. Additionally, the AMF500 may also send a Network Slice Access Layer Group (NSAG) and corresponding priority to the UE400 via the first cell 401 at 504. An NSAG is defined within a TA and identifies a set of slices and priorities within the TA.

[0111] Upon receiving the information, UE400 is connected or active within cell 401 (at 505) and can consume any service, such as an IP call or any other data communication.

[0112] After a certain period of time, for example, due to UE400 being inactive, termination of service consumption, or other network-related reasons, the network may decide to change the status of UE400 to the RRC idle state. Therefore, the network (e.g., cell 1 401) may send an RRC release message to UE400 in 506 to transition the UE's status from the RRC connected state to the RRC idle state. In addition, the connection between the UE and cell 1 401 may be released.

[0113] Simultaneously, the network may, at 507, provide the UE400 with updated cell reselection configuration information and transmit NSAG-specific cell reselection priorities to facilitate cell reselection in RRC idle or RRC inactive states. NSAG-specific cell reselection priorities can be signaled, for example, by broadcast in SIB16 (e.g., the information element cellReselectionPriority or FreqPriorityListNRSlicing, which has a functionally similar information element, see TS38.331). Note that in some embodiments, only NSAGs for specific frequency mappings are signaled without any priority indication (without the CellReselectionPriority information element).

[0114] In RRC idle or RRC active states, the UE400 generally performs cell reselection according to established procedures, namely, measuring the radio conditions of the cell to which the UE400 camps on and neighboring cells. At some point, the UE400 performs cell reselection, taking into account the current radio conditions, as well as other information mentioned above, including the S-NSSAI received at 503, the NSAG with priority received at 504, and / or the NSAG-specific cell reselection priority received at 507, in order to reselect to another second cell or to maintain camp-on in the current first cell 401. In the examples in Figures 7A and 7B, the UE applies a slice-specific cell reselection mechanism at 508 according to the S-NSSAI received at 503, the NSAG with priority received at 504, and the NSAG-specific cell reselection priority received at 508. Even if UE400 receives cell reselection configuration information for other cell reselection mechanisms, and such other cell reselection mechanisms trigger cell reselection, UE400 does not modify the reselection priority due to other factors (e.g., MBS frequency prioritization) and such other cell reselection mechanisms. Rather, UE400 performs cell reselection based on the unmodified reselection priority and camps on or reselects a cell based on the aforementioned information received in 503, 504, and / or 508. In the use cases of Figures 7A and 7B, the slice-specific cell reselection configuration information in 502, 504, and / or 508 allows UE400 to reselect any cell that provides UE400 with one or more functions related to services such as MBS sessions, HSDN transmissions, and / or sidelink communications, so UE400 does not need to consider such other cell reselection mechanisms.

[0115] In this regard, various situations can occur. For example, Figure 7A shows a case where UE400 receives a service announcement (not shown in Figure 6) indicating that service will be provided at the frequency of the second cell 402 (e.g., cell 2) rather than the first cell 401 (e.g., cell 1). However, UE400 applies the MBS-specific cell reselection mechanism, but instead utilizes the S-NSSAI received at 503, the NSAG received at 504, and the NSAG-specific cell reselection priorities received at 508. In the example in Figure 7A, the S-NSSAI prioritizes the first cell 401 over the second cell 402, that is, instructs UE400 to remain at the first cell 401. Therefore, UE400 does not prioritize the frequency of the second cell 402, as it would have in the case of MBS-specific cell reselection. Rather, UE400 uses slice-specific cell reselection and therefore does not reselect to the second cell 402, but camps on to the first cell 401 at 509.

[0116] Another example based on S-NSSAI, NSAG, and NSAG-specific cell reselection priority signaling is given in Figure 7B, where activities 501-508 correspond to those in Figure 7A. However, here, the relevant S-NSSAI instructs to apply slice-specific cell reselection, and the NSAG and NSAG-specific cell reselection priority instruct to prioritize the second cell 402. This can be based on information about UE capabilities and services supported by, or to be provided by, the second cell 402, or currently provided. For example, the network may recognize that UE400 is MBS capable and that the second cell 402 supports MBS, or that an MBS session is currently being broadcast in the second cell 402. Therefore, the S-NSSAI provided in 503, the NSAG provided in 504, and the NSAG-specific cell reselection priorities provided to UE400 in 508 may indicate the slice-specific priority of the second cell 402 compared to the first cell 401. Here again, UE400 may have received an MBS service announcement at some point between activities 506 and 508 indicating that the MBS service will be provided at the frequency of the second cell 402 rather than the first cell 401. Here again, UE400 does not prioritize the frequency of the second cell 402 due to the MBS-specific cell reselection mechanism, but prioritizes the second cell 402 in 508 by applying slice-specific cell reselection. As a result, UE400 reselects to the second cell 402 based on the slice-specific cell reselection mechanism and initiates camp-on in the selected cell (e.g., the second cell) in 510.

[0117] After successfully re-selecting to the second cell 402, UE400 can receive NSAG-specific cell re-selection priorities from the network via the second cell 402, for example, by SIB16, at 511. Additionally, since no MBS sessions are provided in the first cell 401, the network can include the frequencies of the first cell 401 in its S-NSSAI "exclusion list". According to the "exclusion list", UE400 excludes the first cell 401 as a potential candidate for cell re-selection and does not re-select or camp-on to the first cell 401.

[0118] Therefore, in the scenarios of Figures 7A and 7B, the network controls the UE400 to apply slice-specific cell reselection by providing the UE400 with slice-specific cell reselection configuration information that may or may not prioritize cells providing services such as MBS, HSDN, and side links for the purpose of cell reselection. It should be noted that in the examples of Figures 7A and 7B, MBS is mentioned as an example of a primary service or function, but this is only illustrative and can be understood by those skilled in the art to be similarly applicable to any other service using the corresponding cell reselection mechanism. The scenarios of Figures 7A and 7B can be summarized by the UE400 receiving at least one network slice access layer group, an NSAG, and priority information for at least one NSAG. Based on the at least one NSAG and the priority information for at least one NSAG, the UE400 derives a reselection priority for slice-based cell reselection according to a predetermined scheme, and the UE400 does not modify the reselection priority due to other factors of cell reselection, such as MBS-related cell reselection configuration information received by the UE400. As described above, the priority information for at least one NSAG includes the priority for each NSAG and at least one of the priorities of one or more corresponding frequencies mapped to at least one NSAG. Note that the second cell 402 may belong to the same gNB or CU controlling the first cell 401, or to a different gNB controlling the first cell 401.

[0119] In some embodiments, with reference to Figures 8A and 8B, the cell reselection configuration information indicates the priority of a plurality of cell reselection mechanisms. More specifically, in the exemplary embodiments shown in Figures 8A and 8B, the cell reselection configuration information indicates the priority of a plurality of cell reselection mechanisms and includes a sorted list of at least two of the plurality of cell reselection mechanisms. The sorted list may indicate the relative priority between at least two of the plurality of cell reselection mechanisms, for example, the cell reselection mechanism listed first has the highest priority, while the cell reselection mechanism listed last has the lowest priority among the listed cell reselection mechanisms.

[0120] The scenarios in Figures 8A and 8B can incorporate a similar flow to activities 501-506, ultimately resulting in 600, where UE400 is placed in an RRC idle or RRC inactive state. Generally, and as with Figures 7A and 7B, it is assumed that UE400 supports slice-specific cell reselection, but the UE is also interested in receiving services provided by one or more cells in the communications network, such as sidelink / HSDN and broadcast services.

[0121] In embodiments shown in Figures 8A and 8B, the network element providing the first cell 401 signals a list of one or more functions, or more generally, a list of one or more cell reselection mechanisms, in a prioritized manner at 601. This controls the UE to use the most applicable cell reselection mechanism with the highest priority of the signaled functions when performing cell reselection. Each of the one or more functions and one or more corresponding cell reselection mechanisms signaled to the UE 400 may take the form of a list. For example, if the list is configured as {MBS, sidelink, HSDN, slice}, the list indicates that MBS-specific cell reselection has the highest priority and slice-specific cell reselection has the lowest priority. For example, a UE 400 with capability and interest in an MBS service would then apply the MBS-specific cell reselection mechanism when performing a cell reselection procedure. Another UE 400, interested in sidelink communication rather than an MBS session, would prioritize cells using a cell reselection mechanism defined for sidelinks. Generally, the UE400 applies a cell reselection mechanism in 602 according to the priority list received in 601.

[0122] This list of prioritized functions or cell reselection mechanisms can be provided to the UE via an RRC release message when the UE is transitioning from an RRC connection to an RRC idle state. Additionally or alternatively, the list may be broadcast by system information such as SIB16.

[0123] Similar to Figures 7A and 7B, several scenarios can be assumed in the embodiments shown in Figures 8A and 8B. In the example in Figure 8A, the list signaled at 601 may be configured as {slice, sidelink communication, HSDN, MBS}. Thus, UE400 can apply slice-specific cell reselection. As a result, at 603, UE400 uses a slice-specific cell reselection mechanism that causes the UE to remain in the current first cell 401. Thus, as indicated by arrow 603 in Figure 8A, UE400 remains camp-on to the first cell 401.

[0124] Another complementary scenario is depicted in Figure 8B, where the network signals a cell reselection mechanism priority list at 601 indicating {MBS, sidelink, HSDN, slice}. At some point after 602, UE400 may receive an MBS service instruction indicating that an MBS session is to be initiated in a second cell 402. At this point, UE400, interested in the MBS session, prioritizes the MBS frequencies based on the MBS-specific cell reselection mechanism because the cell reselection mechanism priority list received at 601 assigns a higher priority to MBS than slice-specific cell reselection. UE400 then applies the MBS-specific cell reselection based on the list at 601 and subsequently reselects the second cell 402 at 604 to join the MBS session.

[0125] It should be noted that the second cell 402 may belong to the same gNB or CU controlling the first cell 401, or to a different gNB controlling the first cell 401. As mentioned above, in embodiments, the aforementioned cell reselection mechanism is applied when the UE is in an RRC idle state. Alternatively or additionally, in embodiments, the aforementioned cell reselection mechanism is applied when the UE is in an RRC disconnected state.

[0126] From the perspective of user equipment (UE), this disclosure can also be characterized by the following points:

[0127] Point 1: A method for cell reselection, the method being performed by a user device, UE, which is communicably coupled to a network element of a wireless communication network, the method comprising receiving cell reselection configuration information from a network element of a wireless communication network, the cell reselection configuration information including network slice selection assistance information, NSSAI, relating to the service capabilities of the UE and the services provided by the wireless communication network, and indicating the priority of a plurality of cell reselection mechanisms, the method comprising receiving, and applying one of the plurality of cell reselection mechanisms based on the NSSAI or the priority of the plurality of cell reselection mechanisms.

[0128] Point 2: The method according to Point 1, wherein multiple cell reselection mechanisms include slice-specific cell reselection, multicast broadcast service-specific cell reselection, high-speed data network-specific cell reselection, and side-link communication-specific cell reselection.

[0129] Point 3: The method according to Point 2, wherein NSSAI represents one or more cells that provide multicast broadcast service transmission, high-speed data network transmission, or sidelink communication.

[0130] Point 4: The method of Point 3, further comprising: in the UE, receiving an NSSAI from a network element of a wireless communications network indicating one or more cells that provide multicast broadcast service transmission, high-speed data network transmission, or sidelink communication; receiving a service notice indicating that multicast broadcast service transmission, high-speed data network transmission, or sidelink communication is provided in at least one of the one or more cells indicated by the NSSAI; and, based on the NSSAI, applying a slice-specific cell reselection mechanism and reselecting to one of the at least one cells indicated by the NSSAI based on the slice-specific cell reselection mechanism.

[0131] Point 5: The method according to Point 2, wherein NSSAI represents one or more cells that do not provide multicast broadcast service transmission, high-speed data network transmission, or sidelink communication.

[0132] Point 6: The method of Point 5, further comprising: in the UE, receiving an NSSAI from a network element of a wireless communications network indicating one or more cells that do not provide multicast broadcast service transmission, high-speed data network transmission, or sidelink communication; receiving a service notice indicating that multicast broadcast service transmission, high-speed data network transmission, or sidelink communication is provided in at least one of the one or more cells indicated by the NSSAI; and, based on the NSSAI, applying a slice-specific cell reselection mechanism and reselecting to one of the at least one cells indicated by the NSSAI based on the slice-specific cell reselection mechanism.

[0133] Point 7: The method according to Point 2, wherein the cell reselection configuration information indicating the priority of multiple cell reselection mechanisms includes a sorted list of at least two of the multiple cell reselection mechanisms, the sorted list indicating the relative priority between at least two of the multiple cell reselection mechanisms.

[0134] Point 8: The method of Point 7, wherein the priority indicates a priority of a slice-specific cell reselection mechanism that is higher than at least one other cell reselection mechanism among a plurality of cell reselection mechanisms, and the method further comprises the UE receiving a service notice indicating that multicast broadcast service transmission, high-speed data network transmission or sidelink communication is provided in at least one cell of a wireless communications network, and applying a slice-specific cell reselection mechanism based on the priority.

[0135] Point 9: The method of Point 7, wherein the priority indicates the priority of a first cell reselection mechanism among a plurality of cell reselection mechanisms that is higher than a slice-specific cell reselection mechanism, and the method further comprises, in the UE, receiving a service notice indicating that a service transmission corresponding to the first cell reselection mechanism is provided in at least one cell of the wireless communication network, and applying the first cell reselection mechanism based on the priority to reselect one of one or more cells of the wireless communication network to receive the service transmission.

[0136] Point 10: The priority of a first cell reselection mechanism among multiple cell reselection mechanisms is higher than that of a second cell reselection mechanism among multiple cell reselection mechanisms, and therefore higher than that of a slice-specific cell reselection mechanism, the method further comprising: in the UE receiving a service notice indicating that a service transmission corresponding to a second cell reselection mechanism is provided in at least one cell of the wireless communication network; and, based on the priority, applying the second cell reselection mechanism and reselecting one of one or more cells of the wireless communication network to receive the service transmission, the method of Point 7.

[0137] Point 11: Cell reselection configuration information is received through system information and / or dedicated signaling, as described in any one of points 1-10.

[0138] Point 12: Cell re-selection configuration information is a method described in any one of Points 1-11, including an allowed list of cells that will provide a service, or an excluded list of cells that will not provide a service.

[0139] Point 13: When the UE applies the cell reselection mechanism based on the cell reselection configuration information, the method described in any one of points 1 to 12, where the UE is in an idle or inactive state.

[0140] Point 14: The method of any one of Points 1 to 13, comprising receiving at least one network slice access layer group, an NSAG, and priority information of at least one NSAG, and deriving a slice-based cell reselection reselection priority in a predetermined manner based on the at least one NSAG and the priority information of at least one NSAG, wherein the UE does not modify the reselection priority due to other factors of cell reselection.

[0141] The method according to point 15, wherein the priority information for at least one NSAG includes the priority for each NSAG and at least one of the priorities of one or more corresponding frequencies mapped to at least one NSAG.

[0142] Corresponding points can be listed for each device and user equipment category.

[0143] Corresponding points may be described that specify devices, such as user equipment, configured to execute these method points. For example, a device may comprise a processor and memory that stores program instructions that, when executed by the processor, execute the aforementioned UE-related method points.

[0144] It should be understood that the apparatus described herein may include, or be coupled with, other units or modules such as radio components or radio heads used in or for transmitting and / or receiving. Although the apparatus is described as a single entity, different modules and memories may be implemented in one or more physical or logical entities.

[0145] While the embodiments are described in relation to LTE and 5G NR, it should be noted that similar principles apply to other networks and communication systems where high-speed connection re-establishment is required. Thus, although specific embodiments have been described above with reference to specific exemplary architectures of wireless networks, technologies, and standards as examples, the embodiments may be applied to any other suitable forms of communication systems other than those illustrated and described herein.

[0146] While the above describes exemplary embodiments, it should be noted herein that there are several variations and modifications that may be made to the solutions disclosed without departing from the scope of this disclosure.

[0147] Generally, various exemplary embodiments may be implemented in hardware or special-purpose circuits, software, logic, or any combination thereof. Some aspects of this disclosure may be implemented in hardware, while others may be implemented in firmware or software that can be executed by a controller, microprocessor, or other computing device, but this disclosure is not limited thereto. Although various aspects of this disclosure are illustrated and described using block diagrams, flowcharts, or any other graphical descriptions, it will be understood that these blocks, apparatus, systems, techniques, or methods described herein may, in non-limiting examples, be implemented in hardware, software, firmware, special-purpose circuits or logic, general-purpose hardware or controllers or other computing devices, or any combination thereof.

[0148] The exemplary embodiments of this disclosure may be implemented by computer software or hardware, or by a combination of software and hardware, that can be executed by a data processor of a mobile device, such as in a processor entity. Computer software or programs, also called program products, which include software routines, applets and / or macros, may be stored on any device-readable data storage medium and contain program instructions for performing a particular task. A computer program product may include one or more computer executable components configured to perform an embodiment when the program is invoked. One or more computer executable components may be at least one piece of software code or a portion thereof.

[0149] Furthermore, it should be noted that any block of the logic flow, as shown in the diagram, may represent a program step, or an interconnected logic circuit, block, and function, or a combination of a program step and a logic circuit, block, and function. The software may be stored on a memory chip or memory block implemented within a processor, a magnetic medium such as a hard disk or floppy disk, and a physical medium such as an optical medium such as a DVD and its data variants, or a CD. The physical medium is a non-temporary medium.

[0150] Memory may be of any type suitable for the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The data processor may be of any type suitable for the local technical environment and may include, in non-limiting examples, one or more of the following: general-purpose computers, special-purpose computers, microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), FPGAs, gate-level circuits, and processors based on multi-core processor architectures.

[0151] Exemplary embodiments of this disclosure may be practiced in various components, such as integrated circuit modules. Designing integrated circuits is largely a highly automated process. Complex and powerful software tools are available to translate logic-level designs into semiconductor circuit designs that can be easily etched and formed on semiconductor substrates.

[0152] The above description has provided a complete and useful description of exemplary embodiments of the present disclosure, as a non-limiting example. However, when read in conjunction with the accompanying drawings and appended claims, various modifications and adaptations may become apparent to those skilled in the art in light of the above description. However, all such modifications and similar modifications of the teachings of the present disclosure still fall within the scope of the present disclosure as set forth in the appended claims. In fact, further embodiments exist, including one or more embodiments in combination with any of the other embodiments described above.

Claims

1. User equipment, UE, which is communicably coupled to a network element of a wireless communication network, comprises a processor and a memory having instructions, wherein when an instruction is executed by the processor, it is sent to the UE, Receiving a cell reselection priority from the network element, corresponding to a determined priority among one or more functions related to cell reselection, wherein the cell reselection priority includes at least one of a network slice access layer group, an NSAG, a priority, and a slice-specific cell reselection priority mapped to the respective corresponding NSAG, and each of the one or more functions is provided by the wireless communication network and is related to at least one of the UE's service capability and the UE's service request, Even if one or more factors other than slice-based cell reselection trigger the cell reselection, the cell reselection priority is not modified, and a slice-specific cell reselection mechanism is applied based on the NSAG priority or the slice-specific cell reselection priority. UE will perform this action.

2. The UE according to claim 1, further configured to receive authorized network slice selection support information, authorized NSSAI, from the network element, which includes at least one single network slice selection support information, S-NSSAI, associated with one or more functions for cell reselection.

3. The UE according to claim 1, further configured to receive configured network slice selection support information, configured NSSAI, from the network element, which includes at least one single network slice selection support information, S-NSSAI, associated with one or more functions for cell reselection.

4. The UE according to claim 1, wherein the one or more functions include at least one of slice-specific cell reselection, multicast broadcast service, high-speed data network specific, and sidelink communication.

5. The UE according to claim 1, which is made to receive the cell reselection priority by being made to receive the cell reselection priority by system information broadcast or dedicated signaling.

6. It is a method, Receiving a cell reselection priority from a network element, corresponding to a determined priority among one or more functions related to cell reselection, wherein the cell reselection priority includes at least one of a network slice access layer group, an NSAG, a priority, and a slice-specific cell reselection priority mapped to the respective corresponding NSAG, and each of the one or more functions is provided by the wireless communication network and is related to at least one of the UE's service capability and the UE's service request, Even if one or more factors other than slice-based cell reselection trigger the cell reselection, the cell reselection priority is not modified, and a slice-specific cell reselection mechanism is applied based on the NSAG priority or the slice-specific cell reselection priority. Methods that include...

7. The method according to claim 6, further comprising receiving authorized network slice selection support information, authorized NSSAI, from the network element, which includes at least one single network slice selection support information, S-NSSAI, associated with one or more functions for cell reselection.

8. The method according to claim 6, further comprising receiving configured network slice selection support information, configured NSSAI, from the network element, which includes at least one single network slice selection support information, S-NSSAI, associated with one or more functions for cell reselection.

9. The method according to claim 6, wherein the one or more functions include at least one of slice-specific cell reselection, multicast broadcast service, high-speed data network specific, and sidelink communication.

10. The method according to claim 6, further comprising receiving the cell reselection priority by being made to receive the cell reselection priority by a system information broadcast or dedicated signaling.

11. A computer-readable storage medium that, when executed by at least one processor, stores instructions causing a device to perform the method according to any one of claims 6 to 10.

12. The computer-readable storage medium according to claim 11, wherein the computer-readable storage medium is a non-temporary computer-readable medium.

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