Cell reselection mechanism interworking

Abstract

A network element of a wireless communication network is communicatively coupled to a user equipment and identifies a list of one or more features provided by the wireless communication network. Each feature on the list is related to at least one of a service capability of the UE and a service request of the user equipment. The network element determines a priority order between one or more features related to cell reselection and assigns cell reselection priorities to the user equipment according to the priority order, such as by indicating the cell reselection priorities or the priority order of features and a corresponding cell reselection mechanism to the user equipment. The user equipment performs cell reselection by applying a cell reselection mechanism and a cell reselection priority according to the indication of the network element.

Description

Technical Field

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

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

[0003] Network slices can differ in their service requirements, such as ultra-reliable low-latency communications (URLLC) and enhanced mobile broadband (eMBB), or the tenants that provide those services.

[0004] The network slice is uniquely identified via S-NSSAI (Single Network Slice Selection Assistance Information). The current 3GPP specification allows a user equipment (UE) to be simultaneously connected and served by up to eight slices corresponding to eight network slices identified by eight S-NSSAI, refer to 3GPP TS 38.300. On the other hand, a cell may support dozens or even hundreds of slices, for example, in the current specification, a tracking area (TA) may have support for up to 1024 network slices, refer to 3GPP TS 38.423

[0005] The present disclosure relates to improving cell reselection in a network environment with network slicing and slice-specific cell reselection mechanisms. Summary of the invention

[0006] In 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 equipment UE. The network element identifies a list of one or more features provided by the wireless communication network. Each feature on the list is related to at least one of the following: a service capability of the UE and a service request of the UE. The network element determines a priority order between the identified features related to cell reselection, and assigns a cell reselection priority to the UE according to the priority order.

[0007] In some embodiments, assigning cell reselection priorities to the UE comprises indicating to the UE at least one of: a priority order between the cell reselection priorities and the identified characteristics related to the cell reselection.

[0008] In some embodiments, allocating cell reselection priorities for UEs includes: for each of the identified characteristics, determining single network slice selection assistance information S-NSSAI and a corresponding corresponding network slice access layer group NSAG for a slice-specific cell reselection mechanism, indicating to the UE the cell reselection priority corresponding to the determined priority order between the identified characteristics related to cell reselection.

[0009] In some embodiments, the cell reselection priority is indicated in the form of an NSAG priority or as a slice-specific cell reselection priority mapped to a corresponding NSAG.

[0010] In some embodiments, the network element sends allowed network slice selection assistance information NSSAI to the UE, where the allowed NSSAI includes at least one or more S-NSSAI associated with the identified characteristics.

[0011] In some embodiments, the network element sends configured network slice selection assistance information NSSAI to the UE, where the configured NSSAI includes at least one or more S-NSSAI associated with the identified characteristics.

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

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

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

[0015] In some embodiments, allocating cell reselection priorities to the UE includes: signaling the cell reselection priorities to the UE according to the priority order by means of system information broadcast or dedicated signaling.

[0016] According to another aspect, a network element of a wireless communication network is provided. The network element is communicatively coupled to a user equipment (UE) and is arranged to identify a list of one or more features provided by the wireless communication network, wherein each feature on the list is related to at least one of: a service capability of the UE and a service request of the UE, to determine a priority order between the identified features related to cell reselection, and to assign a cell reselection priority to the UE according to the priority order.

[0017] In some embodiments the network element is arranged to be caused to assign a cell reselection priority for a UE by being caused to indicate to the UE at least one of: a priority order between the cell reselection priority and one or more characteristics related to cell reselection.

[0018] In some embodiments, the network element is arranged to determine, for each of the identified characteristics, single network slice selection assistance information S-NSSAI and a corresponding network slice access stratum group NSAG for a slice-specific cell reselection mechanism, and indicate to the UE a cell reselection priority corresponding to a priority order between the determined identified characteristics related to cell reselection.

[0019] In some embodiments, the cell reselection priority is indicated in the form of an NSAG priority or as a slice-specific cell reselection priority mapped to a corresponding NSAG.

[0020] In some embodiments, the network element is arranged to send allowed network slice selection assistance information NSSAI to the UE, the allowed NSSAI comprising at least one or more S-NSSAI associated with the identified characteristics.

[0021] In some embodiments, the network element is arranged to send configured network slice selection assistance information NSSAI to the UE, the configured NSSAI comprising at least one or more S-NSSAI associated with the identified characteristics.

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

[0023] In some embodiments, the features include at least one of: slice-specific cell reselection, multicast broadcast services, high-speed data network-specific communications, and sidelink communications.

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

[0025] In some embodiments, the network element is arranged to be caused to assign a cell reselection priority for a UE by signalling the cell reselection priority to the UE by way of system information broadcast or dedicated signalling.

[0026] According to another aspect, a method for cell reselection is provided. The method is performed by a user equipment UE that is communicatively coupled to a network element of a wireless communication network. The UE receives from the network element at least one of: a cell reselection priority for one or more features related to cell reselection, a priority order between identified features related to cell reselection, wherein each feature is provided by the wireless communication network and is related to at least one of: a service capability of the UE and a service request of the UE. The UE applies a cell reselection mechanism from a plurality of cell reselection mechanisms based on at least one of the cell reselection priority and the priority order.

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

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

[0029] According to yet another aspect, there is provided a user equipment UE, the UE being communicatively coupled to a network element of a wireless communication network. The UE is arranged to receive from the network element of the wireless communication network at least one of: a cell reselection priority and a priority order between characteristics related to cell reselection, wherein each characteristic is provided by the wireless communication network and is related to at least one of: a service capability of the UE and a service request of the UE. The UE is further arranged to apply a cell reselection mechanism from a plurality of cell reselection mechanisms based on at least one of the cell reselection priority and the priority order.

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

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

[0032] According to yet another aspect, a method for cell reselection performed by a user equipment UE is provided. 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 order in one or more characteristics related to cell reselection, wherein the cell reselection priority includes a network slice access stratum group NSAG priority or a slice-specific cell reselection priority mapped to a corresponding NSAG, wherein each characteristic is provided by the wireless communication network and is related to at least one of a service capability of the UE and a service request of the UE. 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 allowed NSSAI from a network element, the allowed NSSAI comprising at least one single network slice selection assistance information S-NSSAI associated with a feature for cell reselection.

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

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

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

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

[0038] According to yet another aspect, a user equipment UE is provided, the UE being communicatively coupled to a network element of a wireless communication network. The UE is arranged to receive from the network element a cell reselection priority corresponding to a determined priority order among one or more characteristics related to cell reselection, wherein the cell reselection priority comprises a network slice access stratum group NSAG priority or a slice-specific cell reselection priority mapped to a respective corresponding NSAG, wherein each characteristic is provided by the wireless communication network and is related to at least one of a service capability of the UE and a service request of the UE. The UE is arranged 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 arranged to receive allowed network slice selection assistance information NSSAI from a network element, the allowed NSSAI comprising at least one single network slice selection assistance information S-NSSAI associated with a feature for cell reselection.

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

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

[0042] In some embodiments, the UE is arranged to receive the cell reselection priority by being caused to receive the cell reselection priority by way of system information broadcast or dedicated signalling.

[0043] According to another aspect, a method for slice-based cell reselection performed by a user equipment is proposed. The user equipment is communicatively coupled to a network element of a wireless communication network. The user equipment receives at least one network slice access layer group NSAG and priority information of the at least one NSAG. The user equipment obtains a reselection priority for slice-based cell reselection according to a predefined scheme (e.g., TS38.304 section 5.2.4.11) based on at least one NSAG and priority information of at least one NSAG. Due to other reasons for cell reselection, the user equipment does not modify the reselection priority. That is, even if one or more other reasons for cell reselection that are different from slice-based cell reselection trigger the cell reselection, the user equipment applies a slice-based cell reselection mechanism.

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

[0045] According to yet another aspect, a user equipment supporting slice-based cell reselection is presented. The user equipment is communicatively coupled to a network element of a wireless communication network, and includes a processor and a memory having instructions, which, when executed by the processor, causes the user equipment to: receive at least one network slice access layer group NSAG and priority information of the at least one NSAG; obtain the reselection priority of the slice-based cell reselection according to a predefined scheme based on the at least one NSAG and the priority information of the at least one NSAG; and do not modify the reselection priority due to other reasons for cell reselection. That is, even if other reasons for cell reselection that are different from slice-based cell reselection trigger cell reselection, the user equipment applies a slice-based cell reselection mechanism.

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

[0047] According to a further aspect, a computer program comprises instructions which, when executed by at least one processor, implement any of the aforementioned method aspects and embodiments.

[0048] According to a further aspect, a computer-readable storage medium stores instructions that, when executed by at least one processor, cause a computer to perform any of the aforementioned method aspects and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The following embodiments will be described in more detail with reference to the accompanying drawings, in which:

[0050] Figure 1 Visualize the slice-based cell reselection process.

[0051] Figure 2 A schematic diagram of an example communication system including a base station and a plurality of communication devices is shown.

[0052] Figure 3 A schematic diagram of an example mobile communication device is shown.

[0053] Figure 4 A schematic diagram of an exemplary control device is shown.

[0054] Figure 5 is a flow chart of a cell reselection process at a general level according to the description herein.

[0055] Figure 6 is a general message sequence representation according to the cell reselection procedure described in this document.

[0056] Fig. 7A and 7B A slice-based cell reselection process based on S-NSSAI and / or NSAG priorities related to one or more characteristics of a wireless communication network is depicted.

[0057] Fig. 8A and 8B A cell reselection process based on a prioritized list of one or more features provided by a wireless communication network is shown. DETAILED DESCRIPTION

[0058] As mentioned above, the network slice is identified by S-NSSAI. S-NSSAI may include a slice service type (SST) and a slice difference distinguisher (SD) field with a total length of 32 bits, or only include the SST field portion, in which case the length of S-NSSAI is 8 bits, refer to 3GPP TS 23.501 and 3GPP TS23.003. The SST field may have standardized values ​​and non-standardized values. Values ​​0 to 127 belong to the standardized SST range. For example, an SST value of 1 may indicate that the slice is suitable for processing 5GeMBB, a value of 2 is used for processing URLLC, etc. SD is defined only by the operator.

[0059] TS23.501 defines a number of types of NSSAI: The allowed NSSAI is the NSSAI provided by the serving PLMN, for example, during the registration process, indicating the S-NSSAI value that the UE can use in the serving PLMN for the current registration area. The configured NSSAI is provided in the UE applicable to one or more PLMNs. The pending NSSAI is provided by the serving PLMN during the registration process, indicating the S-NSSAI for which the authentication and authorization process for network-specific slices is waiting. During registration, the UE provides the requested NSSAI to the serving PLMN. The subscribed S-NSSAI is based on the subscriber information used in the PLMN to which the UE is subscribed.

[0060] A UE in RRC IDLE or RRC INACTIVE state performs cell reselection, which identifies the cell on which the UE is to camp. Cell reselection is based on radio measurements and frequency priorities, refer to 3GPP TS 38.304. The UE receives a general frequency priority in system information, such as a system information block (SIB), and may receive a UE-specific priority in an RRC release message. The validity of the UE-specific priority may be limited by a timer.

[0061] According to 3GPP TS 38.300, the cell reselection criteria involves measurements of the serving cell and neighboring cells: Intra-frequency reselection is based on the ranking of the cells. Inter-frequency reselection is based on the absolute priority of the UE trying to camp on the highest priority frequency available. An NCL (Neighbor Cell List) may be provided by the serving cell to handle specific cases of intra-frequency and inter-frequency neighboring cells. An excluded list may be provided to prevent the UE from reselecting to specific intra-frequency and inter-frequency neighboring cells. An allowed list may be provided to allow the UE to reselect to only specific intra-frequency and inter-frequency neighboring cells. Cell reselection may be speed dependent. Service-specific prioritization is possible.

[0062] Until 3GPP specification Release 17, cell reselection was network slice agnostic. However, the most appropriate cell to be selected by the UE may depend on the slice that the UE intends to use. Therefore, in Release 17, the functionality of slice-based cell reselection is introduced. Therefore, slice-specific cell reselection information may be provided to facilitate the UE to reselect a cell supporting a specific slice. This slice-specific cell reselection mechanism is based on slice-specific cell reselection priorities and enables the UE to reselect a cell on a frequency preferred by the network operator based on the most important (several) network slices for the UE, but this does not guarantee that the UE reselects a cell that supports the allowed network slices or the most important network slices. If the UE reselects a cell that does not support the allowed network slices, the network may still (e.g., depending on the network slice) redirect or switch the UE to a cell that is more suitable for the UE.

[0063] In addition, the concept of slice groups (NSAG-network slice AS group) is introduced to achieve signaling optimization (especially for broadcast) and improve security when announcing S-NSSAI. The UE receives the mapping of slices to NSAGs using non-access stratum (NAS) signaling. The UE can also receive the priority of each NSAG (NSAG-specific cell reselection priority). The broadcast of priority information for slice-specific cell reselection (e.g., slice-specific reselection priority) is performed by each NSAG (nsag-cell reselection priority, refer to 3GPP TS 38.304, subclauses 5.2.4.1 and 5.2.4.11) of the radio access network (RAN) node (such as gNB).

[0064] Figure 1 An exemplary slice-specific cell reselection process is shown. At 11, the UE 400 receives a generic NSAG and a corresponding priority (which is different from the cell reselection priority) from the network, such as the AMF 500, by way of a NAS message. At 12, the UE 400 receives NSAG-specific cell reselection priorities (band priorities per NSAG) from the RAN (e.g., gNB 450) by way of a broadcast (a new SIB may be defined for this purpose) or by way of dedicated signaling such as an RRC release message from an RRC connection to an RRC idle. The cell reselection information received in the dedicated signaling such as the RRC release message takes precedence over the reselection information in the SIB. At 13, the gNB 450 managing the cell may broadcast a list of allowed cells per NSAG or a list of excluded cells per band to support cell reselection at the border area of ​​the tracking area. Assuming that a list exists for a given NSAG and frequency band, it is assumed that the cells in the allowed list or the cells not in the excluded list support the given NSAG. At 14, the UE 400 prioritizes the frequency bands using the NSAG-specific cell reselection priorities (refer to TS 38.304 for further details on how the UE uses the priorities) and, therefore, also considering the cell reselection criteria set forth above, either remains camped on the current serving cell or reselects to another cell.

[0065] In other Release-17 work items, further cell reselection mechanisms are defined, referenced to TS 38.304, also referred to hereinafter as feature-specific cell reselection mechanisms. One of these further cell reselection mechanisms relates to High Speed ​​Data Network (HSDN). When a HSDN-capable UE is in a high mobility state, the UE shall consider the HSDN cell to have the highest priority (i.e., higher than any other network configured priority). When a HSDN-capable UE is not in a high mobility state, the UE shall always consider the HSDN cell to have the lowest priority (i.e., lower than any other network configured priority).

[0066] Another cell reselection mechanism involves Multicast Broadcast Service (MBS). If an MBS-capable UE receives or is interested in receiving an MBS session and can receive this MBS session by camping on a frequency providing the MBS session, the UE may consider the specific frequency as the highest priority during the MBS session as specified in TS 38.300. As long as an MBS-capable UE is receiving or is interested in receiving an MBS session, the UE may consider cell reselection candidate frequencies where the UE cannot receive the MBS session during the MBS broadcast session (refer to TS 38.300).

[0067] Another cell reselection mechanism involves sidelink communications from pre-Release-17. If the UE is configured to perform both NR sidelink communications and V2X (vehicle-to-everything) sidelink communications, the UE may consider frequencies that provide both NR sidelink communications configuration and V2X sidelink communications configuration as the highest priority. If the UE is configured to perform NR sidelink communications and not perform V2X communications, the UE may consider frequencies that provide NR sidelink communications configuration as the highest priority. If the UE is configured to perform V2X sidelink communications and not perform NR sidelink communications, the UE may consider frequencies that provide V2X sidelink communications configuration as the highest priority.

[0068] Currently, there is no provision for the UE to determine which slice provides a broadcast session - not even included in the User Service Description (USD) for an MBS session - because broadcast services can be received by all authorized UEs in a geographic area. Note that this is different from multicast services, where the UE needs to join the multicast session and therefore receive the relevant S-NSSAI in the USD. Therefore, currently, the UE does not need to configure the S-NSSAI that the UE will use for broadcast services in the allowed NSSAI.

[0069] In case of slice-specific cell reselection, the UE shall derive the frequency reselection priority based on the NSAG and its corresponding cell reselection priority. MBS allows the UE to consider MBS frequencies as the highest priority to enhance broadcast service continuity. Similarly, HSDN allows the UE to consider some frequencies as the highest priority. This also applies to sidelink communications.

[0070] Therefore, when the UE intends to use, for example, in addition to feature-specific cell reselection mechanisms (e.g., MBS frequency prioritization), the UE behavior is currently unspecific. More specifically, what it means for example that an MBS frequency is "considered to be the highest priority" can be attributed to several possible interpretations. For example, does MBS override slice-specific priorities or operations in addition to those slice-specific priorities or operations? Among frequencies that are not mapped to any slice-specific priorities, are frequencies for MBS considered to be the highest priority frequencies (i.e., frequencies with slice-specific priorities always have higher priority than MBS)? Are frequencies for MBS considered to be the highest priority frequencies (i.e., even overriding frequencies with slice-specific priorities)? Is MBS considered to be the highest priority frequency in those slices that allow MBS frequencies and within those slices, NSAG-specific priorities are used to select the best frequency to reside on?

[0071] Therefore, an object of the present disclosure is to provide interworking between different cell reselection mechanisms available in Release 17 and potential future cell reselection mechanisms.

[0072] Before explaining the examples in detail, refer to Figures 2 to 4 Certain general principles of wireless communication systems and mobile communication devices are briefly explained to aid understanding of the technology underlying the described examples.

[0073] In such Figure 2 In the wireless communication system 100 shown, mobile communication devices, user equipment, user equipment (UE) 102, 104, 105 are provided with wireless access via at least one base station (e.g., next generation NB, gNB), similar wireless transmission and / or reception node or network node. The base station can be controlled or assisted by at least one appropriate controller device to enable operation of the base station and management of mobile communication devices communicating with the base station. The controller device can be located in a radio access network (RAN) (e.g., the wireless communication system 100) or in a core network (CN) (not shown) and can be implemented as a central device, or its functions can be distributed over several devices. The controller device can be part of the base station and / or provided by a separate entity (such as a radio network controller (RNC) or a central unit (CU)), typically implementing higher network layers such as layer 3 protocols and / or radio resource control (RRC) protocols. In Figure 2In the figure, control means 108 and 109 are shown as controlling the respective macro-level base stations 106 and 107. The control means of the base station may be interconnected with other control entities. The control means typically have memory capacity and at least one data processor. The control means and functions may be distributed among a plurality of control units. In some systems, the control means may additionally or alternatively be arranged in the RNC.

[0074] exist Figure 2 In FIG. 1 , base stations 106 and 107 are shown connected to a wider communications network 113 via a gateway 112. A further gateway function may be provided to connect to another network.

[0075] As used herein, the term "base station" has the full breadth of its ordinary meaning and includes at least a wireless communication 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". A base station and UEs may be configured to communicate over a transmission medium using any of a variety of radio access technologies (RATs) (also referred to as wireless communication technologies or telecommunication standards described below). Figure 2 As shown, while one of the base stations may act as a "serving cell" for a UE, the UE may also be able to receive signals from (and possibly within 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 described above, a base station may include multiple network nodes, such as an upper controller node implementing higher network layers such as Layer 3 / RRC and one or more lower nodes (such as distributed units (DUs)) that typically implement lower network layers such as the physical layer (Layer 1, L1) and Layer 2 (L2). Note that these multiple units may be geographically co-located or not geographically co-located.

[0076] Smaller base stations 116, 118, and 120 may also be connected to the network 113, for example, via a separate gateway function and / or via a controller of a macro station. Base stations 116, 118, and 120 may be pico or femto-class 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 technologies, 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 its various schemes such as interleaved frequency division multiple access (IFDMA), single carrier frequency division multiple access (SC-FDMA) and orthogonal frequency division multiple access (OFDMA), space division multiple access (SDMA), etc.

[0077] An example of a wireless communication system is an architecture standardized by the Third Generation Partnership Project (3GPP). The latest 3GPP-based development is generally referred to as the Long Term Evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio access technology. The various development stages of the 3GPP specification are referred to as releases. The more recent development of LTE is generally referred to as Advanced LTE (LTE-A). LTE (or LTE-A) adopts a radio mobile architecture called Evolved Universal Terrestrial Radio Access Network (E-UTRAN) and a core network called Evolved Packet Core (EPC). The base station of such a system is referred to as an evolved or enhanced Node B (eNB), and provides E-UTRAN features for communication devices, such as user plane packet data convergence / radio link control / media access control / physical layer protocol (PDCP / RLC / MAC / PHY) and control plane radio resource control (RRC) protocol termination. Other examples of radio access systems include those provided by base stations of systems based on technologies such as WLAN and / or Worldwide Microwave Access Interoperability (Wi Max). The base station can provide coverage for an entire cell or similar radio service area. The core network elements include the Mobility Management Entity (MME), the Serving Gateway (S-GW) and the Packet Gateway (P-GW).

[0078] An example of a suitable communication system is the 5G or NR concept. The network architecture in NR can be similar to that of LTE-A. The base station of the NR system can be called the next generation Node B (gNB). Changes to the network architecture may depend on the need to support various radio technologies and more refined quality of service (QoS) support, as well as some on-demand requirements for QoS levels to support quality of experience (QoE) from the user's perspective. In addition, network-aware services and applications, as well as service and application-aware networks, can bring changes to the architecture. Those involve information-centric networks (ICNs) and user-centric content distribution networks (UC-CDN) approaches. NR may use multiple-input multiple-output (MIMO) antennas, more base stations or nodes than LTE (the so-called small cell concept), including macro sites that operate in conjunction with smaller sites, and may also employ various radio technologies to obtain better coverage and enhanced data rates.

[0079] Future networks may utilize network function virtualization (NFV), which is a network architecture concept that proposes virtualizing network node functions into "building blocks" or entities that can be operably connected or linked together to provide services. Virtualized network functions (VNFs) may include one or more virtual machines that use standard or general-purpose servers rather than custom hardware to run computer program code. Cloud computing or data storage may also be utilized. In radio communications, this may mean that node operations are performed at least in part in a server, host, or node that is operably coupled to a remote radio head. Node operations may also be distributed among multiple servers, nodes, or hosts. It should also be understood that the distribution of lags between core network operations and base station operations may be different from that of LTE or even non-existent.

[0080] Example 5G Core Network (CN) includes functional entities. CN is connected to UE through RAN. User Plane Function (UPF) whose role is called PDU Session Anchor (PSA) can be responsible for forwarding frames back and forth between Data Network (DN) and the channel established on 5G for UE to exchange services with DN.

[0081] The UPF is controlled by a Session Management Function (SMF) which receives policies from a Policy Control Function (PCF). The CN may also include an Access and Mobility Function (AMF).

[0082] Now refer to Figure 3 Describing a possible (mobile) communication device 200 in more detail, Figure 3A schematic partial cross-sectional view is shown. Such a mobile communication device 200 is generally referred to as user equipment (UE), user equipment or terminal equipment. Suitable mobile communication device 200 can be provided by any device capable of sending and receiving radio signals. Non-limiting examples include a mobile station (MS) or a mobile device, such as a mobile phone or a device called a smart phone, a computer with a wireless interface card or other wireless interface facilities (e.g., a USB dongle), a personal digital assistant (PDA) or a tablet computer with wireless communication capabilities, or any combination of these, etc. The communication device 200 can provide, for example, communication of data for carrying communication, such as voice, e-mail (e-mail), text message, multimedia, etc. Therefore, many services can be provided and provided via their communication devices. Non-limiting examples of these services include two-way or multi-way calls, data communications or multimedia services or only access to data communication network systems (such as the Internet). Broadcast or multicast data can also be provided. Non-limiting examples of content include downloads, television and radio programs, videos, advertisements, various alarms and other information.

[0083] In industrial applications, the communications 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 would serve as a connection point for one or more connected Ethernet devices (the connection may be wired or non-wired).

[0084] The communication device 200 is typically provided with at least one data processing entity 201, at least one memory 202 and other possible components 203 for software and hardware assisted execution of the tasks it is designed to perform, including control of access and communication with access systems and other communication devices. The data processing, storage and other related control means may be provided on appropriate circuit boards and / or in a chipset 204. The user may control the operation of the communication device 200 through a suitable user interface such as a keypad 205, voice commands, a touch sensitive screen or pad, a combination thereof, etc. A display 208, a speaker and a microphone may also be provided. In addition, the communication device 200 may include appropriate connectors (wired or wireless) to other devices and / or for connecting external accessories (e.g. a hands-free device) to the communication device 200.

[0085] The communication device 200 may receive signals via an air interface or radio interface 207 via appropriate means for receiving, and may transmit signals via appropriate means for transmitting radio signals. Figure 3 In the embodiment of the present invention, the transceiver arrangement is schematically designated by block 206. The transceiver arrangement 206 may be provided, for example, by means of a radio component and an associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the communication device 200.

[0086] If desired, the communication device 200 may also or alternatively be configured to communicate using one or more global navigation satellite systems (GNSS, such as GPS or GLONASS), one or more mobile television broadcast standards (e.g., ATSC-M / H or DVB-H), and / or any other wireless communication protocol. Other combinations of wireless communication standards (including more than two wireless communication standards) are also possible.

[0087] generally, Figure 3 The communication device 200 shown in includes a set of components configured to perform core functions. For example, the set of components can be implemented as a system on a chip (SoC), which can include parts for various purposes. Alternatively, for various purposes, the set of components can be implemented as separate components or groups of components. The set of components can be (communicatively) coupled (e.g., directly or indirectly) to various other circuits of the communication device 200.

[0088] The communication device 200 may include at least one antenna for communicating with a transmitter and a receiver (e.g., a transceiver device 206). Alternatively, the transmitting and receiving antennas may be separate. The communication device 200 may also include a processor (e.g., at least one data processing entity 201), which is configured to provide signals to and receive signals from the transmitter and the receiver, respectively, and control the functions of the communication device 200. The processor may be configured to control the functions of the transmitter and the receiver by implementing control signaling via electrical leads to the transmitter and the receiver. Similarly, the processor may be configured to control other elements of the communication device 200 by implementing control signaling via electrical leads connecting the processor to other elements (such as a display (e.g., display 208) or a memory (e.g., at least one memory 202)). The processor may be embodied in various ways, for example, including circuitry, at least one processing core, one or more microprocessors with an accompanying digital signal processor, one or more processors without an accompanying digital signal processor, one or more coprocessors, one or more multi-core processors, one or more controllers, processing circuitry, one or more computers, various other processing elements including integrated circuits, such as, for example, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), etc., or some combination thereof. Thus, in some examples, a processor may include multiple processors or processing cores.

[0089] The communication device 200 is capable of operating with one or more air interface standards, communication protocols, modulation types, access types, etc. The signals sent and received by the processor may include signaling information in accordance with the air interface standard of the applicable cellular system, and / or any number of different wired or wireless networking technologies, including but not limited to Wi-Fi, WLAN technologies, such as Institute of Electrical and Electronics Engineers (IEEE) 802.11, 802.16, 802.3, ADSL, DOCSIS, etc. In addition, these signals may include voice data, user-generated data, user-requested data, etc.

[0090] For example, the communication device 200 and / or the cellular modem therein may be capable of operating in accordance with various third generation (3G) communication protocols, fourth generation (4G) communication protocols, fifth generation (5G) communication protocols, Internet Protocol Multimedia Subsystem (IMS) communication protocols (such as, for example, Session Initiation Protocol (SIP), etc.), or beyond 5G. For example, the communication device 200 is capable of operating in accordance with 4G wireless communication protocols (such as LTE-A, 5G, etc.) and similar wireless communication protocols that may be subsequently developed.

[0091] It should be understood that the processor may include circuits for implementing 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, etc. The control and signal processing functions of the communication device 200 can be allocated between these devices according to their respective capabilities. The processor may additionally include an internal voice encoder, an internal data modem, etc. In addition, the processor may include functions for operating one or more software programs that may be stored in the memory. Typically, the processor and the stored software instructions may be configured to cause the communication device 200 to perform actions. For example, the processor may be able to operate a connection program, such as a web browser. The connection program may allow the communication device 200 to send and receive web content, such as location-based content, according to protocols such as wireless application protocol (WAP), hypertext transfer protocol (HTTP), etc.

[0092] The communication device 200 may also include a user interface, which includes, for example, a headset or speaker, a ringer, a microphone, a display, a user input interface, etc., which may be operably coupled to the processor. As described above, the display may include a touch-sensitive display, where the user can touch and / or gesture to make a selection, input a value, etc. 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, a ringer, a microphone, a display, etc.). The processor and / or the user interface circuit including the processor may be configured to control one or more functions of one or more elements of the user interface by computer program instructions (e.g., software and / or firmware) stored on a memory accessible to the processor (e.g., a volatile memory, a non-volatile memory, etc.). The communication device 200 may include a battery for powering various circuits associated with the mobile terminal, for example, a circuit that provides mechanical vibration as a detectable output. The user input interface may include a device that allows 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 a display or an externally coupled keyboard.

[0093] The communication device 200 may also include one or more mechanisms for sharing and / or obtaining data. For example, the communication device 200 may include a short-range radio frequency (RF) transceiver and / or interrogator so that data can be shared with and / or obtained from electronic devices based on RF technology. The communication device 200 may include other short-range transceivers, such as infrared (IR) transceivers, Bluetooth TM Wireless technology Bluetooth TM Transceivers, Wireless Universal Serial Bus (USB) Transceivers, Bluetooth TM Low energy transceiver, ZigBee transceiver, ANT transceiver, cellular device to device transceiver, wireless local area network transceiver and / or any other short-range radio technology. The communication device 200 and more specifically the short-range transceiver may be able to send data to and / or receive data from electronic devices near the device, for example within 10 meters. The communication device 200 including a Wi-Fi or WLAN modem may also be able to send and / or receive data from electronic devices according to various wireless networking technologies (including 6LoWPAN, Wi-Fi, Wi-Fi low power, WLAN technologies such as IEEE 802.11 technology, IEEE 802.15 technology, IEEE 802.16 technology, etc.).

[0094] The communication device 200 may include memory, such as one or more subscriber identity modules (SIMs), one or more universal subscriber identity modules (USIMs), one or more removable user identity modules (R-UIMs), one or more embedded universal integrated circuit cards (e UICCs), one or more universal integrated circuit cards (UICCs), etc., which may store information elements related to mobile subscribers. In addition, the communication device 200 may include other removable and / or fixed memory. The communication device 200 may include volatile memory and / or non-volatile memory. For example, the volatile memory may include random access memory (RAM), including dynamic and / or static RAM, on-chip or off-chip cache memory, etc. The non-volatile memory that 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, 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 embedded in the processor. The memory may store one or more software programs, instructions, information, data, etc. that may be used by the device to perform the operations disclosed herein.

[0095] The memory may include an identifier, such as an International Mobile Equipment Identity (IMEI) code, that can uniquely identify the communication device 200. In an example embodiment, the processor may be configured using computer code stored at the memory to cause the processor to perform the operations disclosed herein.

[0096] Some embodiments disclosed herein may be implemented in software, hardware, application logic, or a combination of software, hardware, and application logic. For example, the software, application logic, and / or hardware may reside on a memory, a processor, or an electronic component. In some example embodiments, the application logic, software, or an instruction set is maintained on any of a variety of conventional computer-readable media. In the context of this document, a "computer-readable medium" may be any non-transitory medium that can contain, store, communicate, propagate, or transmit instructions for use by or in conjunction with an instruction execution system, apparatus, or device (such as a computer or data processor circuit), wherein Figure 3 In the examples depicted herein, computer-readable media may include non-transitory computer-readable storage media, which may be any media that can contain or store instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer.

[0097] User equipment (UE) may include a wireless or mobile device, a device having a radio interface for interacting with a RAN (Radio Access Network), a smart phone, a vehicle-mounted device, an IoT device, an M2M device, or other. Such a UE or device may include: at least one processor; and at least one memory including computer program code; wherein the at least one memory and the computer program code are configured to, together with the at least one processor, cause the device to at least perform certain operations, such as an RRC connection to the RAN. The UE is, for example, configured to generate a message (e.g., including a cell ID) to be sent via a radio device for the RAN (e.g., to reach and communicate with a serving cell). The UE may generate, send, and receive an RRC message containing one or more RRC PDUs (packet data units).

[0098] The UE may have different states (for example, according to 3GPP TS 38.331 V16.5.0 (2021-06) sections 42.1 and 4.4, incorporated herein by reference). When an RRC connection has been established, the UE is, for example, in an RRC connected state or in an RRC inactive state.

[0099] In the RRC connected state, the UE can store AS (access stratum) context, transmit unicast data to / from the UE, monitor the control channel associated with the shared data channel to determine whether data is scheduled for the data channel, provide channel quality and feedback information, and perform neighbor cell measurements and measurement reports.

[0100] In some embodiments, the communication device 200 (i.e., UE or user equipment in the network) includes a processor (e.g., at least one data processing entity 201) and a memory (e.g., at least one memory 202). The memory includes computer program code that causes the communication device 200 to perform processing according to the method described below.

[0101] Figure 4An example embodiment of a control device for a communication system is shown, for example, coupled to and / or used to control a station of an access system, such as a RAN node, for example, a base station, an eNB or a gNB, a relay node or a core network node (such as an MME or an S-GW or a P-GW), or a core network function (such as an AMF / SMF), or a server or a host. The method can be embedded in a single control device or across more than one control device. The control device can be integrated with or external to a node or module of a core network or a RAN. In some embodiments, the base station includes a separate control device unit or module. In other embodiments, the control device can be other network elements, such as an RNC or a spectrum controller. In some embodiments, the base station can have such a control device as well as a control device provided in the RNC. The control device 300 can be arranged to provide control of communications in a service area of ​​the system. The control device 300 includes at least one memory 301, at least one data processing unit 302, 303 and an input / output interface 304. Via the interface, the control device 300 can be coupled to a receiver and a transmitter of a base station. The receiver and / or the transmitter can be implemented as a radio front end or a remote radio head.

[0102] Typically, the control device 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 sends them to a processor (e.g., at least one data processing unit 302, 303). The RF transceiver also converts baseband signals received from the processor into RF signals and sends them to the antenna. The processor processes the received baseband signals and calls different functional modules to execute features in the control device 300. A memory (e.g., at least one memory 301) stores program instructions and data for controlling the operation of the control device 300. In Figure 4 In the example of , the control device 300 also includes a protocol stack and a set of control function modules and circuits. The PDU session processing circuit processes the PDU session establishment and modification process. The policy control module configures policy rules for the UE. The configuration and control circuit provides different parameters to configure and control the UE including related functions of mobility management and session management. As examples, suitable processors include 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.

[0103] In some embodiments, the control device 300 (i.e., a base station, a wireless transmission and / or reception point device, or a network node in a network) includes a processor (e.g., at least one data processing unit 302, 303) and a memory (e.g., at least one memory 301). The memory includes computer program code, so that the control device 300 performs the following operations according to the reference Figure 5 and Figure 5 Describes the method to perform the processing.

[0104] Now turn to Figure 5 , a method and a network element for cell reselection are visualized at a general level. The network element forms part of a wireless communication network and may include multiple subcomponents, such as one or more RAN nodes and / or one or more core network nodes. The network element is communicatively coupled to a user equipment UE, and the cell reselection process of the UE will be controlled by the current functionality. The network element may be a base station (e.g., a gNB). At 51, the network element identifies a list of one or more features provided by the wireless communication network, wherein each feature on the list is associated with at least one of the service capabilities of the UE and the service request of the UE. The feature may be a service supported and provided by a wireless network on a specific network slice such as MBS, HSDN, side link, as further explained below. The feature may also be a cell reselection specific to a slice. In an embodiment, the network element determines such features to be included in the list, in which the corresponding cell reselection mechanism is defined in the wireless communication network and the UE has signaled to it that it is interested and / or capable. For example, if the features of the network slice are not supported by the UE and the UE may have signaled this through an earlier capability negotiation, the network element may determine that the network slice is not included in the feature list. On the other hand, if the UE has registered and / or signaled interest in an MBS session, the network element includes MBS on the list of one or more features for cell reselection. Then, at 52, the network element determines a priority order between the identified features that are relevant to cell reselection. Accordingly, each of the identified features corresponds to a cell reselection mechanism, e.g., the feature MBS corresponds to an MBS-specific cell reselection as described above. Thus, the prioritization of the features constitutes a prioritization of the associated or related cell reselection.

[0105] Then, at 53, the network element assigns a cell reselection priority to the UE based on the priority order. The assignment activity or function 53 may include multiple sub-activities or sub-functions involving transmission or signaling to the UE. In some variants, at 54, the network element indicates to the UE at least one of the cell reselection priority and the priority order among the identified features related to cell reselection. As explained in more detail below, the priority order among the listed features is related to cell reselection, or in other words, the priority order in the cell reselection mechanism corresponding to the identified and prioritized features may be indicated in the form of a sorted list, where it has been determined that the first-mentioned features have a higher priority than the later-mentioned features. Reference is made below to Fig. 7A and 7B as well as Fig. 8A and 8B Specific examples are further given.

[0106] In some variants, for each of the identified features, the network element determines single network slice selection assistance information S-NSSAI and a corresponding corresponding network slice access layer group NSAG for a slice-specific cell reselection mechanism. Then, at 55, the network element indicates to the UE a cell reselection priority corresponding to the determined priority order between the identified features related to cell reselection. The cell reselection priority may indicate the priority of the radio frequency mapped to the NSAG, and it may specify the priority of the UE for selecting an available cell during the cell reselection process. More specifically, at 55, the network element indicates the cell reselection priority in the form of an NSAG priority or as a slice-specific cell reselection priority mapped to a frequency corresponding to the NSAG. The network element may also send an allowed NSSAI or a configured NSSAI, wherein at least one or more of the determined S-NSSAIs are associated with the identified features. Generally, the information indicating to the UE by the network element to control the cell reselection behavior of the UE may also be referred to as cell reselection configuration information.

[0107] Figure 6 is a further presentation of the cell reselection process according to the present method. The method can be performed by a UE 400 that is communicatively coupled (i.e., in an active, inactive, or idle state) to a first cell 401 of a wireless communication network. From another perspective, the method is also performed by one or more network elements of the wireless communication network. The network side, i.e., a network element of a wireless communication network such as a gNB (more specifically, a node of a gNB, such as a central unit, CU) sends cell reselection configuration information to the UE 400. The UE 400 that is currently located or residing on 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.

[0108] The cell reselection configuration information potentially includes network slice selection assistance information NSSAI, NSSAI related to one or more features such as service capabilities of the UE and / or services provided by the wireless communication network, and / or indicating the priority of multiple cell reselection mechanisms corresponding to the features. The cell reselection configuration information may include various information that controls and distinguishes the cell reselection behavior of the UE 400. In order to control the UE 400 to apply a slice-specific cell reselection, the cell reselection information includes network slice selection assistance information (NSSAI). In order to control the UE 400 to apply a cell reselection mechanism from multiple cell reselection mechanisms corresponding to a service or feature provided by a network slice of the wireless communication network (such as a multicast broadcast service (MBS), a high-speed data network (HSDN), and / or a sidelink communication), the cell reselection configuration information may indicate the priority of any one of the one or more features and the corresponding cell reselection mechanism. The options, NSSAI, and priority differentiation of the cell reselection mechanism 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 the cell reselection mechanism corresponding to such transmissions may also be applied.

[0109] Prior to signaling the cell reselection priorities to the UE 400, as described above, the network element identifies the features to be considered for prioritization. For example, the UE 400 may indicate to the network an interest in earlier capabilities and / or services, such as support of MBS, etc. Therefore, the UE 400 may send a list of features of interest to the network element in advance to facilitate identification and prioritization of the features and corresponding cell reselection mechanisms. The network element may then identify slice-specific cell reselection and MBS as features to be prioritized, and determine a priority and / or priority order between the two features. Based on the priority and / or priority order, the UE 400 is instructed to apply one of the cell reselection mechanisms, such as slice-specific cell reselection, but not to apply MBS-specific cell reselection, and to reselect to a cell based on the cell reselection priority assigned or provided by the network element.

[0110] Thus, in an embodiment, the cell reselection configuration information may include other information such as cell reselection priorities, including frequency priority related information, such as a list of frequency-mapped NSAGs and corresponding cell reselection priorities for frequencies, lists such as allowed lists, excluded lists, neighbor cell lists, service-specific prioritization information, etc. In some embodiments, the mapping between NSAGs and frequencies is provided together with the corresponding cell reselection priorities for the frequencies, while in other embodiments, the NSAG to frequency mapping is provided on top of the feature-related S-NSSAI as the allowed NSSAI or the configured NSSAI, but the cell reselection configuration information does not include any priority for the frequency mapped to the NSAG. In such an embodiment, the UE 400 is able to reselect to a cell through slice-specific cell reselection based on the NSAG-specific priority and the feature-related S-NSSAI provided as the allowed NSSAI or the configured NSSAI.

[0111] Typically, cell reselection configuration information such as cell reselection priority or priority order between features / cell reselection mechanisms may be sent in a single message, but may be distributed over multiple messages. These messages may include NAS and AS / RAN messages. For example, a portion of the cell reselection configuration information may be sent by the core network via one or more NAS messages, while another portion of the cell reselection configuration information is sent by one or more network elements of a radio access network of the wireless communication network. The cell reselection information may be broadcast to all UEs in the cell 401, and / or may be sent via dedicated signaling, such as via an RRC message, such as an RRC release message that connects the UE from an RRC connection to, for example, an RRC idle state. Thus, the cell reselection information may be sent periodically or on demand, for example, in response to a request by the UE. Part of the cell reselection information may be sent during a specific procedure specified by the 3GPP technical specification, such as a registration procedure including a registration request with a requested NSSAI and a registration response with an allowed NSSAI (indicating an S-NSSAI corresponding to a feature requested or supported by the UE) or a configured NSSAI (indicating an S-NSSAI corresponding to a feature requested or supported by the UE). The cell reselection information provided to UE 400 may reflect UE capabilities and requirements, such as the ability or interest to consume features such as receiving MBS transmissions.

[0112] After receiving the cell reselection configuration information indicating the cell reselection priority, the UE 400 applies a cell reselection mechanism from among the plurality of cell reselection mechanisms, i.e., based on the NSSAI or priority of the plurality of cell reselection mechanisms conveyed by the cell reselection configuration information, at 404. Thus, the UE 400 decides which cell reselection mechanism from among the plurality of cell reselection mechanisms to apply based on the reselection configuration information of a given cell and potentially its own capabilities and current service requirements in order to decide to stay 405 on the current first cell 401 or to reselect 406 to another second cell 402. Note that the second cell 402 may belong to the same gNB or CU controlling the first cell 401 or another gNB controlling the first cell 401.

[0113] Therefore, by determining a slice-specific cell reselection priority that takes precedence over features supported by wireless communication and related to the UE, the UE is able to perform cell reselection to consume features such as MBS by using a slice-based cell reselection mechanism instead of using a cell reselection mechanism specific to a specific feature. In other words, when the UE is in a normal resident state, if the UE supports slice-based cell reselection and has received NSAGs and their priorities from NAS, the UE shall derive the reselection priority according to TS38.304 clause 5.2.4.11, and the reselection priority shall not be modified due to other reasons (e.g., MBS frequency prioritization). That is, even if other reasons for cell reselection that are different from slice-based cell reselection trigger cell reselection, the user equipment applies the slice-based cell reselection mechanism. In this regard, as described above, when NSAG priority is used, ensuring the prioritization of services (e.g., MBS) depends on the network.

[0114] Fig. 7A and 7B A more specific variation of visualizing cell reselection according to the method described herein. More specifically, Fig. 7A and 7BA variant relates to one or more NSSAIs indicating one or more cells providing multicast broadcast service transmission, high-speed data network transmission, or sidelink communication. This controls the UE to utilize slice-specific cell reselection instead of applying a service or feature-related cell reselection mechanism such as MBS-specific cell reselection, but still enables the UE 400 to reselect to a cell that provides a service that the UE 400 is interested in or wants to consume. On the other hand, for any other reason, for example, because a more important service is provided in a cell that does not provide MBS, by providing the UE 400 with the priority of NSSAI and cell reselection / NSAG, the UE 400 can also be controlled to reside on or reselect to a cell that does not provide a service such as MBS. Therefore, generally speaking, this cell reselection configuration information provision method enables the UE 400 to apply a slice-specific cell reselection mechanism regardless of any other potentially related or ongoing service transmission, so that the UE 400 prioritizes cells for cell reselection based on the NSSAI provided by the network.

[0115] For example, reference Fig. 7A , at 501, for example, in this example, UE 400 sends a registration request message to the network via a first cell 401 provided by a RAN element such as a gNB for a core network element such as an access and mobility management function (AMF) 500 of a wireless communication network. The registration request message may include the requested NSSAI information of UE 400, reflecting the capabilities and services that UE 400 may later use.

[0116] Next, at 502, the network includes (multiple) S-NSSAIs (e.g., associated with ongoing MBS services) as allowed NSSAIs (alternatively, as configured NSSAIs). This is based on UE capability information indicating, for example, that UE 400 supports MBS. In other instances, S-NSSAIs related to sidelink communications and / or S-NSSAIs related to high speed data networks (HSDN) may be included based on UE capabilities and UE interest in these services. The information to be included by the network in a response to a registration request message (such as a request accept message discussed below) may be based on, for example, an indication that UE 400 is about to start a service (such as a multicast broadcast service (MBS)) and / or that there is an ongoing service transmission (such as, for example, a broadcast session in a tracking area (TA) in cell 402).

[0117] At 503, a network element such as AMF 500 returns a registration accept message to UE 400 via the first cell 401. Thus, UE 400 receives the registration accept message. As described above, the registration accept message carries the allowed NSSAI including the MBS-related S-NSSAI. In addition, AMF 500 may also send a network slice access layer group (NSAG) and corresponding priorities to UE 400 via the first cell 401 at 504. NSAG is defined within a TA and identifies a set of slices and priorities in the TA.

[0118] Based on the received information, the UE 400 is in a connected or active state (at 505) in the cell 401 and can consume any service such as an IP call or any other data communication.

[0119] After a period of time, for example, due to inactivity of UE 400, end of service consumption or other network-related reasons, the network may decide to change the state of UE 400 to RRC idle state. Therefore, the network (e.g., cell 1 401) may send an RRC release message to UE 400 at 506 to transition the UE state from the RRC connected state to the RRC idle state. In addition, the connection between the UE and cell 1 401 may be released.

[0120] At the same time, the network may send NSAG-specific cell reselection priorities at 507 to provide the UE 400 with updated cell reselection configuration information to facilitate cell reselection in RRC idle or RRC inactive state. The NSAG-specific cell reselection priorities may be sent by broadcast, for example, in SIB16 (e.g., frequency priority list NR slice with information element cell reselection priority or functionally similar information element, refer to TS 38.331). Note that in some embodiments, only NSAGs mapped to a specific frequency are signaled without any priority indication (no cell reselection priority information element).

[0121] In the RRC idle or RRC inactive state, the UE 400 typically performs cell reselection according to established procedures (i.e., measurements of radio conditions of the cell on which the UE 400 is camped and neighboring cells). At some point in time, the UE 400 performs cell reselection, taking into account the current radio conditions and the other information listed 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 remain camped on the current first cell 401. Fig. 7A and Figure 7BIn the example of , the UE applies a slice-specific cell reselection mechanism at 508 based on the S-NSSAI received at 503, the prioritized NSAG received at 504, and the NSAG-specific cell reselection priority received at 508. Due to other reasons (e.g., MBS frequency prioritization) and other cell reselection mechanisms, the UE 400 will not modify the reselection priority, even if the UE 400 has received cell reselection configuration information for such other cell reselection mechanisms and such other cell reselection mechanisms trigger cell reselection. Instead, the UE 400 performs cell reselection based on the unmodified reselection priority and camps on or reselects to a cell based on the above information received at 503, 504 and / or 508. Fig. 7A and 7B In the use case of 502, 504 and / or 508, UE 400 does not need to consider such other cell reselection mechanisms because the slice-specific cellular cell reselection configuration information of 502, 504 and / or 508 enables UE 400 to reselect to any cell that provides one or more relevant features for UE 400, such as services such as MBS sessions, HSDN transmissions and / or sidelink communications.

[0122] In this regard, various situations may arise. For example, Fig. 7A 4 shows a case where UE 400 has received a service announcement (eg, MBS service announcement ( 400 )) indicating that MBS transmission is provided at a frequency of a second cell 402 (eg, cell 2) but not in a first cell 401 (eg, cell 1). Figure 6 However, UE 400 does apply the MBS specific cell reselection mechanism, but the difference is that it utilizes the S-NSSAI received at 503, the NSAG received at 504, and the NSAG specific cell reselection priority received at 508. Fig. 7A In the example of , S-NSSAI prioritizes the first cell 401 over the second cell 402, i.e., indicates to the UE 400 to remain in the first cell 401. Therefore, the UE 400 does not prioritize the frequency of the second cell 402, as would be the case in the case of MBS specific cell reselection. Instead, the UE 400 uses slice-specific cell reselection and therefore does not reselect to the second cell 402 at 509, but instead camps on the first cell 401.

[0123] Figure 7B Another case based on S-NSSAI, NSAG and NSAG-specific cell reselection priority signaling is given, where activities 501 to 508 correspond to Fig. 7AHowever, here, the associated S-NSSAI indicates that slice-specific cell reselection and NSAG and NSAG-specific cell reselection priority are applied to prioritize the second cell 402. This may be based on UE capabilities and information about services supported by the second cell 402 or to be or currently provided in the second cell 402. For example, the network may know that the UE 400 is MBS-capable and the second cell 402 supports MBS, or that an MBS session is currently broadcast in the second cell 402. Therefore, the S-NSSAI provided at 503, the NSAG provided at 504, and the cell reselection priority of the specific NSAG provided to the UE 400 at 508 may indicate a slice-specific priority of the second cell 402 compared to the first cell 401. Similarly, the UE 400 may have received an MBS service announcement at some point in time (e.g., between activities 506 and 508) indicating that an MBS service is provided at the frequency of the second cell 402 but not in the first cell 401. Again, due to the MBS specific cell reselection mechanism, the UE 400 does not prioritize the frequency of the second cell 402, but prioritizes the second cell 402 by applying the slice-specific cell reselection at 508. As a result, at 510, the UE 400 reselects to the second cell 402 based on the slice-specific cell reselection mechanism and begins camping on the selected cell (e.g., the second cell).

[0124] After successfully reselecting to the second cell 402, the UE 400 may receive the NSAG specific cell reselection priority from the network via the second cell 402, for example, through SIB16 at 511. In addition, when the MBS session is not provided in the first cell 401, the network may include the frequency of the first cell 401 as an "excluded list" of the S-NSSAI. According to the "excluded list", the UE 400 excludes the first cell 401 as a potential candidate for cell reselection and does not reselect to or camp on the first cell 401.

[0125] Therefore, in Fig. 7A and 7B In the scenario of , the network controls the UE 400 to apply slice-specific cell reselection by providing the UE 400 with slice-specific cell reselection configuration information, and the UE 400 may or may not prioritize cells providing services such as MBS, HSDN, sidelink, etc. for cell reselection purposes. Note that MBS is mentioned as Fig. 7A and 7B The main service or feature example in the example of FIG. 3 is shown, but the skilled person will understand that this is only an exemplary role and can also be applied to any other service with a corresponding cell reselection mechanism. Fig. 7A and 7BThe scenario can be summarized as UE 400 receiving at least one network slice access layer group, NSAG, and priority information of at least one NSAG. UE 400 obtains the reselection priority of slice-based cell reselection according to a predefined scheme based on at least one NSAG and the priority information of at least one NSAG, and UE 400 does not modify the reselection priority due to other reasons for cell reselection (such as MBS-related cell reselection configuration information received by UE 400). As described above, the priority information of at least one NSAG includes at least one of the priority of each NSAG and one or more priorities of the corresponding one or more frequencies mapped to the at least one NSAG. Note that the second cell 402 may belong to the same gNB or CU that controls the first cell 401 or another gNB that controls the first cell 401.

[0126] In some embodiments, reference is now made to Fig. 8A and 8B , the cell reselection configuration information indicates the priority order of multiple cell reselection mechanisms. More specifically, according to Fig. 8A and 8B In an exemplary embodiment of the present invention, the cell reselection configuration information indicates a priority order of the plurality of cell reselection mechanisms, including a ranked list of at least two of the plurality of cell reselection mechanisms. The ranked list may indicate a relative priority between at least two of the plurality of cell reselection mechanisms, for example, the first listed cell reselection mechanism has the highest priority, and the last listed cell reselection mechanism has the lowest priority among the listed cell reselection mechanisms.

[0127] Fig. 8A and 8B The scenario may include a process similar to activities 501 to 506, so that UE 400 is finally in the RRC idle state or the RRC inactive state at 600. Generally, and similar to Fig. 7A and 7B , assuming that UE 400 supports slice-specific cell reselection, but the UE is also interested in receiving services provided by one or more cells of the communication network (e.g., sidelink / HSDN and broadcast services).

[0128] In accordance with Fig. 8A and 8BIn an embodiment of the present invention, at 601, a network element providing a first cell 401 signals a list of one or more features or more generally one or more cell reselection mechanisms in a prioritized manner. This controls the UE to use the applicable cell reselection mechanism with the highest signaling priority when performing cell reselection. The one or more features and one or more corresponding cell reselection mechanisms signaled to the UE 400, respectively, may take the form of a list. For example, if the list has been configured as {MBS, sidelink, HSDN, slice}, then the list indicates that the cell reselection specific to MBS has the highest priority and the cell reselection specific to the slice has the lowest priority. A UE 400 having the capability and interest in, for example, MBS services then applies the cell reselection mechanism specific to MBS when performing a cell reselection procedure. Another UE 400 having an interest in sidelink communications but not in an MBS session then prioritizes the cells using the cell reselection mechanism defined for the sidelink. Typically, at 602, the UE 400 applies the cell reselection mechanism according to the priority list received at 601.

[0129] This list of prioritized features or cell reselection mechanisms may be provided to the UE via an RRC release message when the UE transitions from RRC connected to RRC idle state. Additionally or alternatively, the list may be broadcast by system information such as SIB16.

[0130] Similar to Fig. 7A and 7B , according to Fig. 8A and 8B Several scenarios can be envisioned in the embodiments of the present invention. Fig. 8A In the example of FIG. 6 , the list signaled at 601 may be configured as {slice, sidelink, HSDN, MBS}. Therefore, the UE 400 may apply a slice-specific cell reselection. Therefore, at 603, the UE 400 uses a slice-specific cell reselection mechanism, which in turn causes the UE to stay in the current first cell 401. Therefore, as Fig. 8A As shown by arrow 603 in FIG. 4 , UE 400 remains camped on the first cell 401 .

[0131] Another complementary scenario consists of Figure 8BDepicted, where the network signals a cell reselection mechanism priority list at 601 indicating {MBS, sidelink, HSDN, slice}. The UE 400 may have received an MBS service indication indicating the start of an MBS session in the second cell 402 at some point after 602. The UE 400 interested in the MBS session then prioritizes the MBS frequencies based on the MBS-specific cell reselection mechanism, because the cell reselection mechanism priority list received at 601 has a higher priority than the slice-specific cell reselection. The UE 400 then applies the MBS-specific cell reselection based on the list at 601, and then reselects to the second cell 402 at 604 to join the MBS session.

[0132] Note that the second cell 402 may belong to the same gNB or CU controlling the first cell 401 or another gNB controlling the first cell 401. As described above, in an embodiment, when the UE is in the RRC idle state, the above cell reselection mechanism is applied. Alternatively or additionally, in an embodiment, when the UE is in the RRC inactive state, the above cell reselection mechanism is applied.

[0133] From the perspective of user equipment (UE), the present disclosure may also be characterized by the following points:

[0134] Point 1: A method for cell reselection, the method being performed by a user equipment UE communicatively coupled to a cell of a wireless communication network, the method comprising: receiving cell reselection configuration information from a network element of the wireless communication network, wherein the cell reselection configuration information comprises network slice selection assistance information, NSSAI, the NSSAI being related to the service capability of the UE and the services provided by the wireless communication network, or indicating a priority order of multiple cell reselection mechanisms; and applying a cell reselection mechanism among the multiple cell reselection mechanisms based on the NSSAI or the priorities of the multiple cell reselection mechanisms.

[0135] Point 2: The method according to point 1, wherein the multiple cell reselection mechanisms include one or more of the following: slice-specific cell reselection, multicast broadcast service-specific cell reselection, high-speed data network-specific cell reselection, and sidelink communication-specific cell reselection.

[0136] Point 3: The method according to point 2, wherein the NSSAI indicates one or more cells providing multicast broadcast service transmission, high-speed data network transmission or sidelink communication.

[0137] Point 4: The method according to point 3 also includes: at the UE, receiving the NSSAI from the network element of the wireless communication network, the NSSAI indicating one or more cells providing multicast broadcast service transmission, high-speed data network transmission or sidelink communication; receiving a service announcement, the service announcement 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; based on the NSSAI, applying the 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.

[0138] Point 5: The method according to point 2, wherein the NSSAI indicates one or more cells that do not provide multicast broadcast service transmission, high-speed data network transmission or sidelink communication.

[0139] Point 6: The method according to point 5 also includes: at the UE, receiving the NSSAI from the network element of the wireless communication network, the NSSAI indicating one or more cells that do not provide multicast broadcast service transmission, high-speed data network transmission or sidelink communication; receiving a service announcement, the service announcement 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; based on the NSSAI, applying the slice-specific cell reselection mechanism, and reselecting to one of the at least one cell indicated by the NSSAI based on the slice-specific cell reselection mechanism.

[0140] Point 7: The method according to point 2, wherein the cell reselection configuration information indicating the priority order of multiple cell reselection mechanisms includes a sorted list of at least two cell reselection mechanisms among the multiple cell reselection mechanisms, and the sorted list indicates the relative priority between the at least two cell reselection mechanisms among the multiple cell reselection mechanisms.

[0141] Point 8: The method according to point 7, wherein the priority order indicates the priority of the slice-specific cell reselection mechanism over at least one other cell reselection mechanism among the multiple cell reselection mechanisms, and the method further includes: receiving a service announcement at the UE, the service announcement indicating that multicast broadcast service transmission, high-speed data network transmission or side link communication is provided in at least one cell of the wireless communication network; and applying the slice-specific cell reselection mechanism based on the priority order.

[0142] Point 9: The method according to point 7, wherein the priority order indicates the priority of a first cell reselection mechanism among the multiple cell reselection mechanisms over the slice-specific cell reselection mechanism, and the method further includes: receiving, at the UE, a service announcement indicating that a service transmission corresponding to the first cell reselection mechanism is provided in one or more cells of the wireless communication network; based on the priority order, applying the first cell reselection mechanism, and reselecting to one of the one or more cells of the wireless communication network to receive the service transmission.

[0143] Point 10: A method according to point 7, wherein the priority order indicates the priority of a first cell reselection mechanism among the multiple cell reselection mechanisms over a second cell reselection mechanism among the multiple cell reselection mechanisms, and further over the slice-specific cell reselection mechanism, the method further comprising: receiving, at the UE, a service announcement indicating that a service transmission corresponding to the second cell reselection mechanism is provided in one or more cells of the wireless communication network; based on the priority order, applying the second cell reselection mechanism, and reselecting to one of the one or more cells of the wireless communication network to receive the service transmission.

[0144] Point 11: According to the method according to any one of points 1 to 10, the cell reselection configuration information is received via system information and / or dedicated signaling.

[0145] Point 12: The method according to any one of points 1 to 11, wherein the cell reselection configuration information comprises an allowed list of cells providing the service or an excluded list of cells not providing the service.

[0146] Point 13: The method according to any one of points 1 to 12, wherein when the cell reselection mechanism is applied based on the cell reselection configuration information, the UE is in an idle state or an inactive state.

[0147] Point 14: The method according to any one of points 1 to 13 includes: receiving priority information of the at least one network slice access layer group NSAG and the at least one NSAG; and based on the at least one NSAG and the priority information of the at least one NSAG, obtaining the reselection priority of the slice-based cell reselection according to a predefined scheme, wherein the UE does not modify the reselection priority due to other reasons for cell reselection.

[0148] The method according to claim 15, wherein the priority information of the at least one NSAG comprises at least one of the following: a priority of each NSAG and one or more priorities of the corresponding one or more frequencies mapped to the at least one NSAG.

[0149] Corresponding points may be listed for device and user equipment categories.

[0150] Corresponding points specifying an apparatus such as a user equipment arranged to perform these method points may be set forth. For example, the apparatus may be equipped with a processor and a memory storing program instructions which, when executed by the processor, implement the above-mentioned UE-related method points.

[0151] It should be understood that the apparatus described herein may include other units or modules in or for transmission and / or reception, such as radio components or radio heads, etc. Although the apparatus has been described as one entity, different modules and memories may be implemented in one or more physical or logical entities.

[0152] Note that while embodiments have been described with respect to LTE and 5G NR, similar principles may be applied with respect to other networks and communication systems that require implementation of fast connection reestablishment. Thus, while certain embodiments are described above by way of example with reference to certain example architectures for wireless networks, technologies, and standards, the embodiments may be applied to any other suitable form of communication system than those shown and described herein.

[0153] It is also noted herein that while the above describes exemplary embodiments, there are several variations and modifications which may be made to the disclosed solution without departing from the scope of the subject disclosure.

[0154] In general, the various exemplary embodiments may be implemented in hardware or dedicated circuits, software, logic, or any combination thereof. Some aspects of the invention may be implemented in hardware, while other aspects may be implemented in firmware or software that may be executed by a controller, microprocessor, or other computing device, but the invention is not limited thereto. Although various aspects of the subject disclosure may be shown and described as block diagrams, flow charts, or using some other graphical representation, it should be understood that the blocks, devices, systems, techniques, or methods described herein may be implemented in non-limiting examples as hardware, software, firmware, dedicated circuits or logic, general-purpose hardware or controllers or other computing devices, or some combination thereof.

[0155] The example embodiments of the present disclosure can be implemented by computer software that can be executed by a data processor of a mobile device, such as in a processor entity, or by hardware, or by a combination of software and hardware. Computer software or programs, also referred to as program products (including software routines, applets and / or macros), can be stored in any device-readable data storage medium, and they include program instructions for performing specific tasks. A computer program product may include one or more computer executable components that are configured to perform an embodiment when the program is running. One or more computer executable components may be at least one software code or part thereof.

[0156] Further, in this regard, it should be noted that any block of the logic flow in the accompanying drawings may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on such physical media as memory chips or memory blocks implemented within a processor, magnetic media (such as hard disk or floppy disk), and optical media (such as, for example, DVD and its data variant CD). Physical media are non-transitory media.

[0157] The 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. As non-limiting examples, the data processor may be of any type suitable for the local technical environment and may include one or more of a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), an FPGA, a gate-level circuit, and a processor based on a multi-core processor architecture.

[0158] Example embodiments of the present disclosure can be practiced in various components such as integrated circuit modules. The design of integrated circuits is a highly automated process. Complex and powerful software tools are available to convert logic level designs into semiconductor circuit designs that are ready to be etched and formed on semiconductor substrates.

[0159] The above description provides a complete and informative description of exemplary embodiments of the subject disclosure by way of non-limiting examples. However, in view of the foregoing description, various modifications and amendments may become apparent to those skilled in the relevant art when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings of the present disclosure will still fall within the scope of the subject disclosure defined in the appended claims. In fact, further embodiments include a combination of one or more embodiments with any other embodiments previously discussed.

Claims

1. A method for cell reselection, the method being performed by a network element of a wireless communication network, the network element being communicatively coupled to a user equipment (UE), the method comprising: identifying a list of one or more features provided by the wireless communication network, wherein each feature on the list is related to at least one of: a service capability of the UE and a service request of the UE, determining an order of priority between the one or more characteristics relevant to cell reselection, A cell reselection priority is assigned to the UE based on the priority order.

2. The method according to claim 1, wherein allocating a cell reselection priority to the UE comprises: Indicating to the UE at least one of: the priority order between the cell reselection priority and the one or more features related to cell reselection.

3. The method according to claim 1, wherein allocating a cell reselection priority to the UE comprises: For each of the one or more characteristics, determining single network slice selection assistance information S-NSSAI and a corresponding corresponding network slice access stratum group NSAG for a slice-specific cell reselection mechanism, A cell reselection priority corresponding to the determined priority order among the one or more characteristics related to cell reselection is indicated to the UE.

4. The method of claim 3, wherein the cell reselection priority is indicated in the form of at least one of: an NSAG priority and a slice-specific cell reselection priority mapped to the corresponding NSAG.

5. The method according to claim 3 or 4, further comprising: Sending allowed network slice selection assistance information NSSAI to the UE, wherein the allowed NSSAI includes at least the one or more S-NSSAI associated with the one or more features.

6. The method according to claim 3 or 4, further comprising: The configured network slice selection assistance information NSSAI is sent to the UE, wherein the configured NSSAI includes at least the one or more S-NSSAI associated with the one or more features.

7. The method according to any one of claims 1 to 6, wherein the list of one or more features is determined based on a list of one or more features of interest received from the UE.

8. The method according to any one of claims 1 to 7, wherein the one or more features include at least one of the following: specific to slice cell reselection, multicast broadcast service, specific to high-speed data network and / or sidelink communication.

9. The method according to any one of claims 1 to 8, wherein the one or more features related to cell reselection are features having a corresponding cell reselection mechanism.

10. The method according to any one of claims 1 to 9, wherein allocating a cell reselection priority to the UE comprises: The cell reselection priority is signaled to the UE according to the priority order by means of system information broadcast or dedicated signaling.

11. A network element of a wireless communication network, the network element being communicatively coupled to a user equipment (UE) and comprising a processor and a memory having instructions which, when executed by the processor, cause the network element to: identifying a list of one or more features provided by the wireless communication network, wherein each feature on the list is related to at least one of: a service capability of the UE and a service request of the UE, determining an order of priority between the one or more characteristics relevant to cell reselection, A cell reselection priority is assigned to the UE based on the priority order.

12. The network element of claim 11, wherein the network element is caused to assign a cell reselection priority for the UE by being caused to indicate to the UE at least one of: the cell reselection priority and the priority order between the one or more characteristics related to cell reselection.

13. The network element of claim 11, wherein the network element is caused to assign a cell reselection priority for the UE by: For each of the one or more characteristics, determining single network slice selection assistance information S-NSSAI and a corresponding corresponding network slice access stratum group NSAG for a slice-specific cell reselection mechanism, A cell reselection priority corresponding to the determined priority order among the one or more characteristics related to cell reselection is indicated to the UE.

14. The method of claim 13, wherein the cell reselection priority is indicated in the form of at least one of: an NSAG priority and a slice-specific cell reselection priority mapped to a corresponding NSAG.

15. The network element according to claim 13 or 14 is also configured to send allowed network slice selection assistance information NSSAI to the UE, wherein the allowed NSSAI includes at least the one or more S-NSSAI associated with the one or more features.

16. The network element according to claim 13 or 14 is also configured to send configured network slice selection assistance information NSSAI to the UE, and the configured NSSAI includes at least the one or more S-NSSAI associated with the one or more features.

17. The network element of any of claims 11 to 16, wherein the list of the one or more features is based on a list of one or more features of interest received from the UE.

18. The network element according to any one of claims 11 to 17, wherein the one or more features include at least one of the following: specific to slice cell reselection, multicast broadcast service, specific to high-speed data networks, and sidelink communication.

19. The network element according to any one of claims 11 to 18, wherein the one or more features related to cell reselection are one or more features having a corresponding cell reselection mechanism.

20. The network element according to any one of claims 11 to 19, wherein the network element is caused to allocate a cell reselection priority for the UE by signaling the cell reselection priority to the UE by means of system information broadcast or dedicated signaling.

21. A user equipment (UE) communicatively coupled to a network element of a wireless communication network and comprising a processor and a memory having instructions which, when executed by the processor, cause the UE to: receiving a cell reselection priority from the network element, the cell reselection priority corresponding to the priority order between the determined one or more characteristics related to cell reselection, wherein the cell reselection priority comprises at least one of: a network slice access stratum group (NSAG) priority and a slice-specific cell reselection priority mapped to a respective corresponding NSAG, wherein each of the one or more characteristics is provided by the wireless communication network and is related to at least one of: a service capability of the UE and a service request of the UE; Based on the NSAG priority or based on the slice-specific cell reselection priority, a slice-specific cell reselection mechanism is applied.

22. The UE according to claim 21, further being caused to: Allowed network slice selection assistance information NSSAI is received from the network element, the allowed NSSAI comprising at least one single network slice selection assistance information S-NSSAI associated with the one or more features for cell reselection.

23. The UE according to claim 21, further being caused to: Configured network slice selection assistance information NSSAI is received from the network element, the configured NSSAI including at least one single network slice selection assistance information S-NSSAI associated with the one or more features for cell reselection.

24. The UE according to any one of claims 21 to 23, wherein the one or more features include at least one of the following: slice cell reselection specific, multicast broadcast service specific, high-speed data network specific, and sidelink communication.

25. The UE according to claim 21, being configured to receive the cell reselection priority by the following operation: receiving the cell reselection priority by means of system information broadcast or dedicated signaling.

26. A method for slice-based cell reselection performed by a user equipment, the method comprising: Receiving at least one network slice access layer group NSAG and priority information of the at least one NSAG; as well as Based on the at least one NSAG and the priority information of the at least one NSAG, obtaining a reselection priority of the slice-based cell reselection according to a predefined scheme, Even if other reasons for cell reselection that are different from slice-based cell reselection trigger the cell reselection, the user equipment does not modify the reselection priority.

27. The method of claim 26, wherein the priority information of the at least one NSAG comprises at least one of: a priority of each NASG and one or more priorities for corresponding one or more frequencies mapped to the at least one NSAG.

28. A user equipment supporting slice-based cell reselection, comprising a processor and a memory having instructions, the instructions, when executed by the processor, causing the user equipment to: Receiving at least one network slice access stratum group NSAG and priority information of the at least one NSAG; and Based on the at least one NSAG and the priority information of the at least one NSAG, obtaining a reselection priority of the slice-based cell reselection according to a predefined scheme, The processor and the memory enable: even if other reasons for cell reselection that are different from slice-based cell reselection trigger the cell reselection, the user equipment does not modify the reselection priority.

29. The user equipment of claim 28, wherein the priority information of the at least one NSAG comprises at least one of the following: a priority of each NASG and one or more priorities for corresponding one or more frequencies mapped to the at least one NSAG.

30. A computer-readable storage medium storing instructions which, when executed by at least one processor, cause a computer to perform the method according to any one of claims 1 to 10 or implement the method according to any one of claims 26 to 27.

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