Method for checking whether slice support is available and user device

Abstract

A slice support confirmation method according to one aspect is a slice support existence confirmation method in a mobile communication system. The slice support confirmation method includes a step for a base station to transmit a message including a first list and / or a second list. In addition, the slice support confirmation method includes a step for a user device to determine, on the basis of the existence of the first list and the second list, whether a cell supports a network slice in an application area. Here, the first list represents a first network slice that is supported by the cell, and the second list represents a second network slice that is not supported by the cell.

Description

[Technical Field]

[0001] The present disclosure relates to a method for checking whether slice support is available in a mobile communication system and a user device. [Background technology]

[0002] Network slicing is defined in the specifications of the Third Generation Partnership Project (3GPP) (registered trademark; the same applies hereinafter), a standardization project for mobile communication systems (see, for example, Non-Patent Document 1). Network slicing is a technology that configures network slices, which are virtual networks, by logically dividing a physical network constructed by a telecommunications carrier. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] 3GPP TS 38.300 V16.8.0 (2021-12) Summary of the Invention

[0004] A slice support confirmation method according to one aspect is a method for confirming whether or not a slice is supported in a mobile communication system. The slice support confirmation method includes a step of a base station transmitting a message including a first list and / or a second list. The slice support confirmation method also includes a step of a user equipment determining whether or not a cell in an application area supports network slices based on the presence or absence of the first list and the second list. Here, the first list represents first network slices supported by the cell, and the second list represents second network slices not supported by the cell.

[0005] A user device according to one embodiment is a user device in a mobile communication system. The user device includes a receiving unit that receives a message including a first list and / or a second list from a base station. The user device also includes a control unit that determines whether a cell in an application area supports network slices based on the presence or absence of the first list and the second list. Here, the first list represents a first network slice supported by the cell, and the second list represents a second network slice not supported by the cell. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a mobile communication system according to the first embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of a UE (user equipment) according to the first embodiment. [Figure 3] FIG. 3 is a diagram illustrating an example configuration of a gNB (base station) according to the first embodiment. [Figure 4] FIG. 4 is a diagram illustrating an example of the configuration of a protocol stack related to a user plane according to the first embodiment. [Figure 5] FIG. 5 is a diagram illustrating an example of the configuration of a protocol stack related to the control plane according to the first embodiment. [Figure 6] FIG. 6 is a diagram for explaining an outline of the cell reselection procedure. [Figure 7] FIG. 7 is a diagram illustrating a general flow of a general cell reselection procedure. [Figure 8] FIG. 8 is a diagram illustrating an example of network slicing. [Figure 9] FIG. 9 is a diagram outlining a slice-specific cell reselection procedure. [Figure 10] FIG. 10 is a diagram illustrating an example of slice frequency information. [Figure 11] FIG. 11 is a diagram illustrating the basic flow of a slice-specific cell reselection procedure. [Figure 12]FIG. 12(A) is a diagram showing combinations of whether or not a list is present according to the first embodiment, and FIG. 12(B) is a diagram showing an example of the correspondence between whether or not a list is present and the type of operation according to the first embodiment. [Figure 13] FIG. 13(A) is a diagram showing an example of the correspondence between the action type and the action content according to the first embodiment, and FIG. 13(B) is a diagram showing an example of the area type according to the first embodiment. [Figure 14] FIG. 14 is a diagram illustrating an example of operation according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] A user equipment in a Radio Resource Control (RRC) idle state or an RRC inactive state performs a cell reselection procedure. 3GPP is considering a slice-specific cell reselection, which is a network slice-dependent cell reselection procedure.

[0008] One aspect of the present disclosure aims to provide a slice support confirmation method that can confirm whether a cell supports network slices.

[0009] A mobile communication system according to an embodiment will be described with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

[0010] [First embodiment] (Configuration of a mobile communication system) FIG. 1 is a diagram illustrating the configuration of a mobile communication system according to a first embodiment. The mobile communication system 1 conforms to the 3GPP standard 5th Generation System (5GS). In the following description, 5GS is used as an example, but the mobile communication system may also be at least partially based on an LTE (Long Term Evolution) system. Alternatively, the mobile communication system may also be at least partially based on a sixth generation (6G) system.

[0011] The mobile communication system 1 includes a user equipment (UE) 100, a 5G radio access network (NG-RAN) 10, and a 5G core network (5GC) 20. Hereinafter, the NG-RAN 10 may be simply referred to as the RAN 10. The 5GC 20 may be simply referred to as the core network (CN) 20.

[0012] The UE 100 is a mobile wireless communication device. The UE 100 may be any device that is used by a user. For example, the UE 100 may be a mobile phone terminal (including a smartphone), a tablet terminal, a laptop PC, a communication module (including a communication card or a chipset), a sensor or a device provided in a sensor, a vehicle or a device provided in a vehicle (Vehicle UE), or an aircraft or a device provided in an aircraft (Aerial UE).

[0013] The NG-RAN 10 includes a base station (called "gNB" in the 5G system) 200. The gNBs 200 are connected to each other via an Xn interface, which is an interface between base stations. The gNB 200 manages one or more cells. The gNB 200 performs wireless communication with a UE 100 that has established a connection with its own cell. The gNB 200 has a radio resource management (RRM) function, a routing function for user data (hereinafter simply referred to as "data"), a measurement control function for mobility control and scheduling, etc. The term "cell" is used to indicate the smallest unit of a wireless communication area. The term "cell" is also used to indicate a function or resource that performs wireless communication with a UE 100. One cell belongs to one carrier frequency (hereinafter simply referred to as "frequency").

[0014] In addition, gNBs can also connect to the Evolved Packet Core (EPC), which is the LTE core network. LTE base stations can also connect to 5GC. LTE base stations and gNBs can also be connected via a base station-to-base station interface.

[0015] The 5GC20 includes an Access and Mobility Management Function (AMF) and a User Plane Function (UPF) 300. The AMF performs various mobility controls for the UE 100. The AMF manages the mobility of the UE 100 by communicating with the UE 100 using NAS (Non-Access Stratum) signaling. The UPF controls data forwarding. The AMF and UPF are connected to the gNB 200 via an NG interface, which is an interface between a base station and a core network.

[0016] 2 is a diagram showing the configuration of a UE 100 (user equipment) according to the first embodiment. The UE 100 includes a receiving unit 110, a transmitting unit 120, and a control unit 130. The receiving unit 110 and the transmitting unit 120 constitute a wireless communication unit that performs wireless communication with the gNB 200.

[0017] The receiving unit 110 performs various types of reception under the control of the control unit 130. The receiving unit 110 includes an antenna and a receiver. The receiver converts a radio signal received by the antenna into a baseband signal (received signal) and outputs the baseband signal to the control unit 130.

[0018] The transmitting unit 120 performs various transmissions under the control of the control unit 130. The transmitting unit 120 includes an antenna and a transmitter. The transmitter converts a baseband signal (transmission signal) output by the control unit 130 into a radio signal and transmits it from the antenna.

[0019] The control unit 130 performs various controls and processes in the UE 100. Such processes include processes in each layer, which will be described later. The control unit 130 includes at least one processor and at least one memory. The memory stores programs executed by the processor and information used in the processes by the processor. The processor may include a baseband processor and a CPU (Central Processing Unit). The baseband processor performs modulation / demodulation and encoding / decoding of baseband signals. The CPU executes programs stored in the memory to perform various processes. Note that the control unit 130 may perform each process or operation in the UE 100 in each of the embodiments described below.

[0020] 3 is a diagram showing the configuration of a gNB200 (base station) according to the first embodiment. The gNB200 includes a transmitter 210, a receiver 220, a controller 230, and a backhaul communication unit 240. The transmitter 210 and the receiver 220 constitute a wireless communication unit that performs wireless communication with the UE 100. The backhaul communication unit 240 constitutes a network communication unit that performs communication with the CN20.

[0021] The transmission unit 210 performs various transmissions under the control of the control unit 230. The transmission unit 210 includes an antenna and a transmitter. The transmitter converts a baseband signal (transmission signal) output by the control unit 230 into a radio signal and transmits it from the antenna.

[0022] The receiving unit 220 performs various types of reception under the control of the control unit 230. The receiving unit 220 includes an antenna and a receiver. The receiver converts a radio signal received by the antenna into a baseband signal (received signal) and outputs the baseband signal to the control unit 230.

[0023] The control unit 230 performs various controls and processes in the gNB 200. Such processes include processes in each layer, which will be described later. The control unit 230 includes at least one processor and at least one memory. The memory stores programs executed by the processor and information used in the processes by the processor. The processor may include a baseband processor and a CPU. The baseband processor performs modulation / demodulation and encoding / decoding of baseband signals, etc. The CPU executes programs stored in the memory to perform various processes. Note that the control unit 230 may perform each process or operation in the gNB 200 in each of the embodiments described below.

[0024] The backhaul communication unit 240 is connected to neighboring base stations via an Xn interface, which is an interface between base stations. The backhaul communication unit 240 is connected to the AMF / UPF 300 via an NG interface, which is an interface between a base station and a core network. Note that the gNB 200 may be configured (i.e., functionally divided) with a CU (Central Unit) and a DU (Distributed Unit), and both units may be connected via an F1 interface, which is a fronthaul interface.

[0025] FIG. 4 is a diagram showing the configuration of a protocol stack of a radio interface of a user plane that handles data.

[0026] The user plane radio interface protocol includes a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, and a service data adaptation protocol (SDAP) layer.

[0027] The PHY layer performs encoding / decoding, modulation / demodulation, antenna mapping / demapping, and resource mapping / demapping. Data and control information are transmitted between the PHY layer of UE100 and the PHY layer of gNB200 via a physical channel. The PHY layer of UE100 receives downlink control information (DCI) transmitted from gNB200 on a physical downlink control channel (PDCCH). Specifically, UE100 performs blind decoding of the PDCCH using a radio network temporary identifier (RNTI) and acquires successfully decoded DCI as DCI addressed to the UE. The DCI transmitted from gNB200 has CRC parity bits scrambled by the RNTI added.

[0028] The MAC layer performs data priority control, retransmission processing using Hybrid Automatic Repeat reQuest (HARQ), random access procedures, etc. Data and control information are transmitted between the MAC layer of UE100 and the MAC layer of gNB200 via transport channels. The MAC layer of gNB200 includes a scheduler, which determines the uplink and downlink transport format (transport block size, modulation and coding scheme (MCS)) and the resource blocks to be allocated to UE100.

[0029] The RLC layer transmits data to the RLC layer on the receiving side using the functions of the MAC layer and PHY layer. Data and control information are transmitted between the RLC layer of the UE 100 and the RLC layer of the gNB 200 via logical channels.

[0030] The PDCP layer performs header compression / decompression, encryption / decryption, etc.

[0031] The SDAP layer maps IP flows, which are the units for Quality of Service (QoS) control by the core network, to radio bearers, which are the units for QoS control by the Access Stratum (AS). Note that if the RAN is connected to the EPC, SDAP is not necessary.

[0032] FIG. 5 is a diagram showing the configuration of a protocol stack of a radio interface of a control plane that handles signaling (control signals).

[0033] The protocol stack of the radio interface of the control plane has a Radio Resource Control (RRC) layer and a Non-Access Stratum (NAS) instead of the SDAP layer shown in FIG.

[0034] RRC signaling for various settings is transmitted between the RRC layer of UE100 and the RRC layer of gNB200. The RRC layer controls logical channels, transport channels, and physical channels according to the establishment, re-establishment, and release of radio bearers. When there is a connection (RRC connection) between the RRC of UE100 and the RRC of gNB200, UE100 is in an RRC connected state. When there is no connection (RRC connection) between the RRC of UE100 and the RRC of gNB200, UE100 is in an RRC idle state. When the connection between the RRC of UE100 and the RRC of gNB200 is suspended, UE100 is in an RRC inactive state.

[0035] The NAS, which is located above the RRC layer, performs session management, mobility management, etc. NAS signaling is transmitted between the NAS of the UE 100 and the NAS of the AMF 300. Note that the UE 100 has an application layer and the like in addition to the radio interface protocol. The layer below the NAS is called an AS (Access Stratum).

[0036] (Overview of cell reselection procedure) FIG. 6 is a diagram for explaining an overview of a cell reselection procedure.

[0037] When the UE 100 is in an RRC idle state or an RRC inactive state, it performs a cell reselection procedure to transition from a current serving cell (cell #1) to a neighboring cell (any of cells #2 to #4) as it moves. Specifically, the UE 100 identifies a neighboring cell on which it should camp by the cell reselection procedure, and reselects the identified neighboring cell. When the current serving cell and the neighboring cell have the same frequency (carrier frequency), this is called intra-frequency, and when the current serving cell and the neighboring cell have different frequencies (carrier frequencies), this is called inter-frequency. The current serving cell and the neighboring cell may be managed by the same gNB 200 or different gNBs 200.

[0038] FIG. 7 is a diagram illustrating a general flow of a typical (or legacy) cell reselection procedure.

[0039] In step S11, the UE 100 performs a frequency prioritization process based on the priority (also referred to as "absolute priority") for each frequency specified by the gNB 200, for example, by a system information block or an RRC release message. Specifically, the UE 100 manages the frequency priority specified by the gNB 200 for each frequency.

[0040] In step S12, UE 100 performs a measurement process to measure radio quality for each of the serving cell and the neighboring cell. UE 100 measures the received power and received quality of reference signals transmitted by each of the serving cell and the neighboring cell, specifically, CD-SSB (Cell Defining-Synchronization Signal and PBCH block). For example, UE 100 always measures radio quality for frequencies having a higher priority than the frequency priority of the current serving cell, and for frequencies having a priority equal to or lower than the frequency priority of the current serving cell, UE 100 measures the radio quality of the frequency having the same priority or lower priority when the radio quality of the current serving cell falls below a predetermined quality.

[0041] In step S13, UE 100 performs a cell reselection process to reselect a cell on which UE 100 will camp based on the measurement result in step S20. For example, if the frequency priority of a neighboring cell is higher than the priority of a current serving cell and the neighboring cell satisfies a predetermined quality standard (i.e., a minimum required quality standard) for a predetermined period, UE 100 may perform cell reselection to the neighboring cell. If the frequency priority of the neighboring cell is the same as the priority of the current serving cell, UE 100 may rank the radio qualities of the neighboring cells and perform cell reselection to the neighboring cell having a higher rank than the rank of the current serving cell for a predetermined period. If the frequency priority of the neighboring cell is lower than the priority of the current serving cell and the radio quality of the current serving cell is lower than a certain threshold and the radio quality of the neighboring cell is higher than another threshold, UE 100 may perform cell reselection to the neighboring cell.

[0042] (Network Slicing Overview) Network slicing is a technology that creates multiple virtual networks by virtually dividing a physical network constructed by a carrier (for example, a network consisting of NG-RAN10 and 5GC20). Each virtual network is called a network slice. In the following, a network slice may be simply referred to as a "slice."

[0043] Network slicing allows telecommunications operators to create slices that meet the service requirements of different service types, such as eMBB (enhanced Mobile Broadband), URLLC (Ultra-Reliable and Low Latency Communications), and mMTC (massive Machine Type Communications), thereby optimizing network resources.

[0044] FIG. 8 is a diagram illustrating an example of network slicing.

[0045] Three slices (slice #1 to slice #3) are configured on a network 50 configured with an NG-RAN 10 and a 5GC 20. Slice #1 is associated with a service type called eMBB, slice #2 is associated with a service type called URLLC, and slice #3 is associated with a service type called mMTC. Note that three or more slices may be configured on the network 50. One service type may be associated with multiple slices.

[0046] Each slice is provided with a slice identifier that identifies the slice. An example of a slice identifier is S-NSSAI (Single Network Slicing Selection Assistance Information). S-NSSAI includes an 8-bit SST (slice / service type). S-NSSAI may further include a 24-bit SD (slice differentiator). SST is information indicating the service type to which the slice is associated. SD is information for differentiating multiple slices associated with the same service type. Information including multiple S-NSSAIs is called NSSAI (Network Slice Selection Assistance Information).

[0047] Furthermore, one or more slices may be grouped to form a slice group. A slice group is a group including one or more slices, and a slice group identifier is assigned to the slice group. The slice group may be configured by a core network (e.g., AMF 300) or a radio access network (e.g., gNB 200). The configured slice group may be notified to UE 100.

[0048] Furthermore, UE 100 determines a desired slice that it wishes to use. A desired slice is sometimes called an "intended slice." In the first embodiment, UE 100 determines a slice priority for each network slice (desired slice). For example, the NAS of UE 100 determines the slice priority based on the operation status of an application in UE 100 and / or a user operation / setting, and notifies the AS of slice priority information indicating the determined slice priority.

[0049] (Overview of slice-specific cell reselection procedure) FIG. 9 is a diagram illustrating an overview of a slice-specific cell reselection (also referred to as slice-aware cell reselection or slice-based cell reselection) procedure.

[0050] In the slice-specific cell reselection procedure, the UE 100 performs a cell reselection process based on slice frequency information provided by the network 50. The slice frequency information may be provided to the UE 100 from the gNB 200 by broadcast signaling (e.g., a system information block) or dedicated signaling (e.g., an RRC release message).

[0051] The slice frequency information indicates the correspondence between network slices, frequencies, and frequency priorities. For example, for each slice (or slice group), the slice frequency information indicates the frequency (one or more frequencies) that supports the slice and the frequency priority assigned to each frequency. An example of the slice frequency information is shown in FIG. 10.

[0052] In the example shown in Fig. 10, three frequencies F1, F2, and F4 are associated with slice #1 as frequencies supporting slice #1. Of these three frequencies, F1 has a frequency priority of "6," F2 has a frequency priority of "4," and F4 has a frequency priority of "2." In the example of Fig. 10, the larger the frequency priority number, the higher the priority; however, it may also be the case that the smaller the number, the higher the priority.

[0053] Furthermore, three frequencies F1, F2, and F3 are associated with slice #2 as frequencies supporting slice #2. Of these three frequencies, F1 has a frequency priority of "0," F2 has a frequency priority of "5," and F3 has a frequency priority of "7."

[0054] Furthermore, three frequencies F1, F3, and F4 are associated with slice #3 as frequencies supporting slice #3. Of these three frequencies, F1 has a frequency priority of "3," F3 has a frequency priority of "7," and F4 has a frequency priority of "2."

[0055] Hereinafter, the frequency priority indicated in the slice frequency information may be referred to as a "slice-specific frequency priority" to distinguish it from the absolute priority in the conventional cell reselection procedure.

[0056] As shown in FIG. 9, UE 100 may perform a cell reselection process based on slice support information provided by network 50. The slice support information may be information indicating a correspondence between a cell (e.g., a serving cell and each neighboring cell) and a network slice that the cell does not provide or provides. For example, a cell may temporarily not provide some or all network slices due to congestion or other reasons. That is, even if a slice support frequency has the capability to provide a certain network slice, some cells within the frequency may not provide the network slice. UE 100 can identify the network slices that each cell does not provide based on the slice support information. Such slice support information may be provided to UE 100 by broadcast signaling (e.g., a system information block) or dedicated signaling (e.g., an RRC release message) from gNB 200.

[0057] 11 is a diagram showing a basic flow of a slice-specific cell reselection procedure. Before starting the slice-specific cell reselection procedure, the UE 100 is in an RRC idle state or an RRC inactive state, and has received and stored the above-mentioned slice frequency information. Note that the procedure of "slice-specific cell reselection" is represented by a "slice-specific cell reselection procedure." However, hereinafter, "slice-specific cell reselection" and "slice-specific cell reselection procedure" may be used interchangeably.

[0058] In step S0, the NAS of UE 100 determines slice identifiers of desired slices of UE 100 and slice priorities of each desired slice, and notifies the AS of UE 100 of slice priority information including the determined slice priorities. A "desired slice" is an "intended slice" and includes a slice that is likely to be used, a candidate slice, a desired slice, a slice to be communicated, a requested slice, an allowed slice, or an intended slice. For example, the slice priority of slice #1 is determined to be "3," the slice priority of slice #2 is determined to be "2," and the slice priority of slice #3 is determined to be "1." A larger number for the slice priority indicates a higher priority, but a smaller number may also indicate a higher priority.

[0059] In step S1, the AS of the UE 100 sorts the slices (slice identifiers) notified from the NAS in step S0 in descending order of slice priority. The list of slices sorted in this way is called a "slice list."

[0060] In step S2, the AS of the UE 100 selects one network slice in descending order of slice priority. The network slice selected in this manner is called a "selected network slice."

[0061] In step S3, the AS of UE100 assigns frequency priorities to each frequency associated with the selected network slice. Specifically, the AS of UE100 identifies a frequency associated with the slice based on slice frequency information, and assigns frequency priorities to the identified frequencies. For example, if the selected network slice selected in step S2 is slice #1, the AS of UE100 assigns frequency priority "6" to frequency F1, frequency priority "4" to frequency F2, and frequency priority "2" to frequency F4 based on slice frequency information (e.g., information in FIG. 10). The AS of UE100 calls the list of frequencies arranged in descending order of frequency priority a "frequency list."

[0062] In step S4, the AS of UE 100 selects one frequency in descending order of frequency priority for the selected network slice selected in step S2, and performs measurement processing on the selected frequency. The frequency selected in this manner is called a "selected frequency." The AS of UE 100 may rank the cells measured within the selected frequency in descending order of wireless quality. Among the cells measured within the selected frequency, a cell that satisfies a predetermined quality standard (i.e., a required minimum quality standard) is called a "candidate cell."

[0063] In step S5, the AS of UE100 identifies the highest-ranked cell based on the result of the measurement process in step S4, and determines whether the cell provides the selected network slice based on the slice support information. If it is determined that the highest-ranked cell provides the selected network slice (step S5: YES), in step S5a, the AS of UE100 reselects the highest-ranked cell and camps on the cell.

[0064] On the other hand, if it is determined that the highest-ranked cell does not provide the selected network slice (step S5: NO), in step S6, the AS of UE 100 determines whether or not there is an unmeasured frequency in the frequency list created in step S3. In other words, the AS of UE 100 determines whether or not there is a frequency assigned in step S3 other than the selected frequency in the selected network slice. If it is determined that there is an unmeasured frequency (step S6: YES), the AS of UE 100 resumes processing on the frequency with the next highest frequency priority and performs measurement processing with that frequency as the selected frequency (returning to step S4).

[0065] If it is determined that there are no unmeasured frequencies in the frequency list created in step S3 (step S6: NO), in step S7, the AS of UE100 may determine whether or not there are any unselected slices in the slice list created in step S1. In other words, the AS of UE100 may determine whether or not there are any network slices other than the selected network slice in the slice list. If it is determined that there are any unselected slices (step S7: YES), the AS of UE100 resumes processing on the network slice with the next highest slice priority and selects that network slice as the selected network slice (returns processing to step S2). Note that in the basic flow shown in FIG. 11, the processing of step S7 may be omitted.

[0066] If it is determined that there is no unselected slice (step S7: NO), in step S8, the AS of UE 100 performs a conventional cell reselection process. The conventional cell reselection process may mean the entire general (or legacy) cell reselection procedure shown in Fig. 7. Alternatively, the conventional cell reselection process may mean only the cell reselection process (step S30) shown in Fig. 7. In the latter case, UE 100 may use the measurement result in step S4 without measuring the radio quality of the cell again.

[0067] The general cell reselection procedure shown in Fig. 7 may be referred to as a "legacy cell reselection procedure." Although the "legacy cell reselection procedure" represents the procedure for "legacy cell reselection," in the following, "legacy cell reselection" and "legacy cell reselection procedure" may be used interchangeably.

[0068] (Method for checking presence or absence of slice support according to the first embodiment) As described above, in step S3 of slice-specific cell reselection, UE 100 determines, for example, whether the highest-ranked cell provides the selected network slice based on slice support information. The slice support information includes, for example, information indicating a correspondence relationship between a cell and a network slice that the cell provides or does not provide.

[0069] Here, for the network slices included in the slice support information, it is also possible to identify each network slice using S-NSSAI. However, one S-NSSAI is represented by 32 bits. Therefore, if the slice support information includes multiple network slices, the slice support information will use a very large number of bits.

[0070] Therefore, it is possible to combine multiple network slices included in the slice support information into one (or multiple) network slice groups (hereinafter, this may be referred to as a "slice group function"). That is, the slice support information includes information indicating the correspondence between a cell and a network slice group that the cell provides or does not provide. This makes it possible to reduce the number of bits in the slice support information compared to when each network slice is represented individually by an S-NSSAI.

[0071] However, there is a possibility that the slice group function will not be introduced in 3GPP because there are discussions within 3GPP about the details of the slice group function, such as how to determine the maximum number of network slices included in a slice group.

[0072] Therefore, in the first embodiment, a slice support confirmation method that can confirm whether a cell supports network slices is described.

[0073] Specifically, first, a base station (e.g., gNB200) transmits a message including a first list and / or a second list. Second, a user equipment (e.g., UE100) determines whether a cell in an application area supports network slices based on the presence or absence of the first list and the second list. Here, the first list represents first network slices supported by the cell, and the second list represents second network slices not supported by the cell.

[0074] Thus, in the first embodiment, UE100 determines whether a cell supports a slice based on the presence or absence of the first list and the second list, thereby making it possible to determine step S3 in slice-specific cell reselection.

[0075] Here, the first list is, for example, a PCI (Physical Cell ID) Allow list. First, the PCI Allow list may be a list representing cells that support a network slice. Alternatively, the PCI Allow list may be a list representing a network slice (e.g., a first network slice) supported by a cell. Second, the PCI Allow list may be a list representing frequencies that support a network slice. Alternatively, the PCI Allow list may be a list representing a network slice supported in a frequency. In this case, the frequency represents all cells that support the frequency. Therefore, when the relationship between a network slice and a frequency is represented in the PCI Allow list, it represents that the network slice is supported in all cells that support the frequency. Note that the cells included in the PCI Allow list may be neighboring cells adjacent to the serving cell.

[0076] Furthermore, the second list is, for example, a PCI Exclude list. First, the PCI Exclude list may be a list representing cells that do not support a network slice. Alternatively, the PCI Exclude list may be a list representing a network slice (e.g., a second network slice) that a cell does not support. Second, the PCI Exclude list may be a list representing frequencies that do not support a network slice. Alternatively, the PCI Exclude list may be a list representing a network slice that is not supported in a frequency. In this case, the frequency represents all cells that support the frequency. Therefore, when the relationship between a network slice and a frequency is represented in the PCI Exclude list, it represents that the network slice is not supported in all cells that support the frequency. Note that the cells included in the PCI Exclude list may be neighboring cells adjacent to the serving cell.

[0077] The gNB200 generates a PCI Allow list and / or a PCI Exclude list and determines an area to which the PCI Allow list and / or the PCI Exclude list apply. The gNB200 determines the area using homogeneous deployment. Homogeneous deployment represents uniformity in the target area. In other words, by applying homogeneous deployment, it becomes possible to uniformly apply the relationship between cells (or frequencies) and network slices indicated by the PCI Allow list and / or the PCI Exclude list in the target area of ​​the homogeneous deployment.

[0078] Here, the target area may be a Tracking Area (TA), a Registration Area (RA), or a Public Land Mobile Network (PLMN). A TA includes one or more cells and indicates an area where a UE 100 in an RRC idle state can move without updating its MME. An RA includes one or more cells and is defined as a set of TAs. Since an RA includes multiple TAs, the number of times that registration update signaling is transmitted can be reduced compared to when the registration update signaling is transmitted for each TA. Furthermore, a PLMN indicates an area where a communication carrier can provide services.

[0079] The area of ​​interest may also be an area represented by multiple cells, multiple TAs, multiple RAs, or multiple PLMNs.

[0080] In this way, by using homogeneous deployment, the settings of the areas to which the PCI Allow list and / or PCI Exclude list apply can be reused across multiple cells, making it possible to reduce processing effort in the gNB200 and UE100 compared to when the areas to which the PCI Allow list and / or PCI Exclude list apply are set for each cell.

[0081] The gNB200 transmits a message including a PCI Allow list and / or a PCI Exclude list and an area type indicating an area to which the PCI Allow list and / or the PCI Exclude list applies. The area type is an identifier indicating an area to which homogeneous deployment applies. For example, if the area type is "5", the applicable area is PLMN, and if the area type is "4", the applicable area is RA, etc. The message is, for example, an RRC message. That is, the gNB200 may transmit the message by broadcast signaling (for example, an SIB (System Information Block)) or dedicated signaling (for example, an RRCRelease (RRC Release) message).

[0082] Then, UE100 determines whether the cell in the area supports network slicing based on the presence or absence of a PCI Allow list and a PCI Exclude list. That is, UE100 determines whether the cell supports network slicing based on whether the message includes a PCI Allow list and whether the message includes a PCI Exclude list.

[0083] Fig. 12(A) is a diagram showing combinations of whether or not a list is included in the message according to the first embodiment. In Fig. 12(A), "Yes" indicates that the list is included in the message, and "No" indicates that the list is not included in the message. As shown in Fig. 12(A), there are a total of four combinations of whether or not the PCI Allow list and the PCI Exclude list are included in the message.

[0084] In the first embodiment, the UE 100 determines how to operate using the PCI Allow list and the PCI Exclude list, based on the combination of the presence or absence of the list. The UE 100 determines whether the cell supports network slicing based on the operation content.

[0085] Fig. 12(B) is a diagram showing an example of the correspondence between the presence or absence of a list and the operation type according to the first embodiment. Also, Fig. 13(A) is a diagram showing an example of the correspondence between the operation type and the operation content according to the first embodiment.

[0086] First, if the PCI Allow list and the PCI Exclude list are not included in the message, UE100 performs an operation according to the operation content representing operation type "3". That is, UE100 separately checks whether the cell supports network slicing. If the PCI Allow list and the PCI Exclude list are not included in the message, UE100 has not received either the PCI Allow list or the PCI Exclude list, and is unable to determine whether the cell supports network slicing. Therefore, UE100 separately checks whether network slicing is supported. Specifically, UE100 checks whether slice support is supported based on PCI related to slice support included in the NAS message received from AMF300. UE100 checks whether slice support is supported based on slice information in an IE (Information Element) or UAC (Unified Access Control) included in the SIB broadcast from gNB200. The slice information indicates a network slice not supported in the cell. UE100 determines whether the cell supports network slicing based on the received information.

[0087] Second, if the message includes a PCI Exclude list and does not include a PCI Allow list, UE100 performs an operation according to the operation content representing operation type "1". That is, UE100 determines that a cell not listed in the PCI Exclude list is a reselection candidate in slice-specific cell reselection. Alternatively, UE100 applies slice-specific cell reselection to a cell not listed in the PCI Exclude list. That is, when UE100 receives a PCI Exclude list but does not receive a PCI Allow list, it determines that cells other than those excluded in the PCI Exclude list are cells that support the network slice and sets them as reselection candidates in slice-specific cell reselection.

[0088] Third, if the message includes a PCI Allow list and does not include a PCI Exclude list, UE100 performs an operation according to the operation content representing operation type "2". That is, UE100 excludes cells not listed in the PCI Allow list from reselection candidates in slice-specific cell reselection. Alternatively, UE100 applies legacy cell reselection to cells not listed in the PCI Allow list. That is, when UE100 receives a PCI Allow list but does not receive a PCI Exclude list, UE100 determines that cells other than those allowed in the PCI Allow list are cells that do not support network slices and excludes them from reselection candidates in slice-specific cell reselection. Legacy cell reselection shown in FIG. 7 may be performed on those cells. In this case, UE100 may determine that cells allowed in the PCI Allow list are cells that support network slices and may set those cells as reselection candidates in slice-specific cell reselection (or may apply slice-specific cell reselection to those cells).

[0089] Fourth, if the message includes a PCI Allow list and a PCI Exclude list, UE100 performs an operation according to the operation content representing the operation type "4". That is, UE100 sets an allowed cell listed in the PCI Allow list as a reselection candidate in slice-specific cell reselection, or applies slice-specific cell reselection to the cell. Furthermore, UE100 excludes an excluded cell listed in the PCI Exclude list from slice-specific cell reselection candidates, or applies legacy cell reselection (FIG. 7) to the cell. That is, when UE100 receives both the PCI Allow list and the PCI Exclude list, UE100 determines whether a cell supports network slicing according to each list. Specifically, when UE100 receives both lists, UE100 may determine that a cell listed in the PCI Allow list is a cell that supports network slicing, and may determine that a cell listed in the PCI Exclude list is a cell that does not support network slicing. Then, UE100 may perform the operation represented by the operation type "4" based on such a determination result.

[0090] Fig. 13(B) is a diagram showing an example of area types according to the first embodiment. Fig. 13(B) shows identifiers of areas to which the PCI Allow list and / or the PCI Exclude list are uniformly applied. The area type indicates, for example, an area to which homogeneous deployment is applied. As shown in Fig. 13(B), when the area type is "5", it indicates that the area is a PLMN, and when the area type is "4", it indicates that the area is an RA. The area to which homogeneous deployment is applied may be expressed by frequency (area type "6"). In this case, it may indicate, for example, that the PCI Allow list and / or the PCI Exclude list are applied to the serving frequency, and that the PCI Allow list and / or the PCI Exclude list are not applied to frequencies other than the serving frequency.

[0091] (Operation example according to the first embodiment) FIG. 14 is a diagram illustrating an example of operation according to the first embodiment.

[0092] As shown in Figure 14, in step S20, CN20 determines network slice deployment. For example, AMF300 determines the area where homogeneous deployment is applied. AMF300 may determine the NSSAI applicable within the PLMN (i.e., Configured NSSAI) or the NSSAI applicable within the RA (i.e., Allowed NSSAI).

[0093] In step S21, AMF300 notifies gNB200 of information regarding the determined network slice deployment. For example, AMF300 transmits an NG message including information regarding network slice deployment, such as information regarding the area to which homogeneous deployment is applied, to gNB200. At this timing, AMF300 may transmit an NAS message including Configured NSSAI and Allowed NSSAI to UE100.

[0094] In step S22, gNB200 sets a PCI Allow list and / or a PCI Exclude list and the area type to which the list applies based on information regarding network slice deployment received from CN20.

[0095] In step S23, the gNB200 transmits the PCI Allow list and / or the PCI Exclude list and the area type. The gNB200 may transmit (or broadcast) a message including the PCI Allow list and / or the PCI Exclude list and the area type as an RRC message (for example, an SIB or an RRC release message). The gNB200 may also transmit (or broadcast) an RRC message (for example, an SIB or an RRC release message) including information linking the presence or absence of the PCI Allow list and the PCI Exclude list with the operation type of UE100 (FIG. 13(A)). The linking of the presence or absence of the PCI Allow list and the PCI Exclude list with the operation type of UE100 is determined in a specification, and UE100 may operate in accordance with the specification. In this case, the gNB200 does not need to transmit the linking information.

[0096] In step S24, UE100 determines the operation type in the application area based on the presence or absence of the PCI Allow list and the PCI Exclude list. As described above, UE100 determines whether the cell supports network slicing through the determination of the operation type. UE100 may determine the operation type according to the linking information received from gNB200. Alternatively, UE100 may determine the operation type according to the specification.

[0097] In step S25, the UE 100 performs slice-specific cell reselection based on the operation type of the UE 100. However, the UE 100 may perform legacy cell reselection according to the operation type.

[0098] (Modification of the first embodiment) Next, a modification of the first embodiment will be described.

[0099] In the first embodiment, an example in which the gNB 200 transmits the area type has been described, but this is not limiting. For example, the gNB 200 may not transmit the area type. For example, an application area to which the PCI Allow list and / or the PCI Exclude list is applied may be determined by a specification. The UE 100 can determine and execute an operation type in the application area in accordance with the specification. However, even in this case, the application area may be a TA, RA, or PLMN, as in the first embodiment. Alternatively, the application area may be multiple cell areas, multiple TAs, multiple RAs, or multiple PLMNs, as in the first embodiment.

[0100] Furthermore, in the first embodiment, an example has been described in which the presence or absence of a PCI Allow list and a PCI Exclude list and the operation type of UE 100 are defined in the specifications, but this is not limiting. For example, the specifications may define the association between the presence or absence of a PCI Allow list and a PCI Exclude list, the operation type of UE 100, and an application region (or area type). That is, the operation type of UE 100 is determined according to the presence or absence of a PCI Allow list and a PCI Exclude list, and the application region to which the operation type is applied is determined. For example, it is assumed that, in the specifications, when the PCI Allow list is "present" and the PCI Exclude list is "absent", the operation type is defined as "2" and the application region is defined as "5". In this case, when the PCI Allow list is "present" and the PCI Exclude list is "absent", UE 100 performs the operation of operation type "2" shown in FIG. 13(A) and applies this operation in area type "5" shown in FIG. 13(B). Even in this case, the gNB 200 only needs to transmit the PCI Allow list and / or the PCI Exclude list, and does not need to transmit the area type, and does not need to transmit information linking the presence or absence of the PCI Allow list and the PCI Exclude list with the operation type of the UE 100. Alternatively, such linking may not be defined in the specifications, and may be transmitted from the gNB 200 as linking information. The gNB 200 may transmit an RRC message including the linking information.

[0101] [Other embodiments] A program may be provided that causes a computer to execute each process performed by the UE 100 or the gNB 200. The program may be recorded on a computer-readable medium. Using the computer-readable medium, the program can be installed on a computer. Here, the computer-readable medium on which the program is recorded may be a non-transitory recording medium. The non-transitory recording medium is not particularly limited, and may be, for example, a recording medium such as a CD-ROM or a DVD-ROM.

[0102] In addition, circuits that execute each process performed by UE100 or gNB200 may be integrated, and at least a portion of UE100 or gNB200 may be configured as a semiconductor integrated circuit (chip set, SoC: System on a chip).

[0103] As used in this disclosure, the terms "based on" and "depending on" do not mean "based only on" or "depending only on," unless expressly stated otherwise. The term "based on" means both "based only on" and "based at least in part on." Similarly, the term "depending on" means both "depending only on" and "depending at least in part on." Furthermore, the terms "include," "comprise," and variations thereof do not mean including only the listed items, but may mean including only the listed items or may include additional items in addition to the listed items. Furthermore, the term "or," as used in this disclosure, is not intended to mean an exclusive or. Furthermore, any reference to elements using designations such as "first," "second," etc., as used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used herein as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed therein or that the first element must precede the second element in some way. In this disclosure, where articles are added by translation, such as a, an, and the in English, these articles shall include the plural unless the context clearly indicates otherwise.

[0104] Although one embodiment has been described in detail above with reference to the drawings, the specific configuration is not limited to the above, and various design changes can be made within the scope of the gist. Furthermore, it is also possible to combine all or part of each embodiment, each operation, each process, and each step within the scope of consistent combinations.

[0105] This application claims priority from Japanese Patent Application No. 2022-069719 (filed April 20, 2022), the entire contents of which are incorporated herein by reference.

[0106] (Addendum) In one embodiment, (1) a method for checking whether slice support is available in a mobile communication system, comprising: a step in which a base station transmits a message including a first list and / or a second list; and a step in which a user equipment determines whether a cell in an application area supports network slices based on the presence or absence of the first list and the second list, wherein the first list represents a first network slice supported by the cell, and the second list represents a second network slice not supported by the cell.

[0107] (2) The slice support confirmation method of (1) above may further include a step in which, in the determining step, if the message includes the first list and the second list, the user equipment determines whether the cell supports the network slice according to the first list and the second list.

[0108] (3) The slice support confirmation method of (1) or (2) above may further include a step in which, if the message does not include the first list and the second list in the determining step, the user equipment either receives slice support information indicating whether the cell supports the network slice from an access management device, or receives the slice support information broadcast from the base station.

[0109] (4) Any of the slice support confirmation methods (1) to (3) above may further include a step in which, in the determining step, if the message includes the first list and the message does not include the second list, the user equipment excludes the cell not listed in the first list from slice-specific cell reselection candidates.

[0110] (5) Any of the slice support confirmation methods (1) to (4) above may further include, in the excluding step, a step in which the user equipment applies legacy cell reselection to the excluded cell.

[0111] (6) Any of the slice support confirmation methods (1) to (5) above may further include a step in which, in the determining step, if the message includes the second list and the message does not include the first list, the user equipment designates the cell not listed in the second list as a slice-specific cell reselection candidate.

[0112] (7) Any of the slice support confirmation methods (1) to (6) above may further include, in the transmitting step, a step in which the base station transmits the message including the first list and / or the second list and an area type representing the application area.

[0113] In one embodiment, (8) a user device in a mobile communication system, comprising: a receiving unit that receives a message including a first list and / or a second list from a base station; and a control unit that determines whether a cell in an application area supports a network slice based on the presence or absence of the first list and the second list, wherein the first list represents a first network slice supported by the cell, and the second list represents a second network slice not supported by the cell. [Explanation of symbols]

[0114] 1: Mobile communication system 20 :CN 100:UE 110: Receiving unit 120: Transmitter 130: Control unit 200 :gNB 210: Transmission unit 220: Receiving unit 230: Control unit 300 :AMF

Claims

1. A method for checking whether slice support is available in a mobile communication system, comprising: a base station transmitting a message including at least one of a first list and a second list and an area type indicating an application area to which the at least one list applies; and determining, by a user equipment, whether a cell in the coverage area supports network slicing based on the presence or absence of the first list and the second list; the application area includes a plurality of cells; A method for checking whether slice support is available, wherein the first list represents a first network slice supported by the plurality of cells included in the application area, and the second list represents a second network slice not supported by the plurality of cells included in the application area.

2. When the message includes the first list and the second list, the determining step includes the user equipment determining whether the cell supports the network slice according to the first list and the second list. The method for checking the presence or absence of slice support according to claim 1.

3. The determining step includes, when the message does not include the first list and the second list, the user equipment performing one of receiving slice support information indicating whether the cell supports the network slice from an access management device and receiving the slice support information broadcast from the base station. The method for checking the presence or absence of slice support according to claim 1.

4. The determining step includes, when the message includes the first list and the message does not include the second list, excluding the cell not listed in the first list from slice-specific cell reselection candidates by the user equipment. The method for checking the presence or absence of slice support according to claim 1.

5. The excluding includes the user equipment applying legacy cell reselection to the excluded cell. The method for checking the presence or absence of slice support according to claim 4.

6. The determining step includes, when the message includes the second list and the message does not include the first list, determining by the user equipment that the cell not listed in the second list is a slice-specific cell reselection candidate. The method for checking the presence or absence of slice support according to claim 1.

7. A user equipment in a mobile communication system, a receiving unit that receives, from a base station, a message including at least one of a first list and a second list and an area type that indicates an application area to which the at least one list is applied; a control unit that determines whether a cell in the application area supports network slicing based on the presence or absence of the first list and the second list, the application area includes a plurality of cells; A user equipment, wherein the first list represents a first network slice supported by the plurality of cells included in the coverage area, and the second list represents a second network slice not supported by the plurality of cells included in the coverage area.

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