Communication control method, user equipment and processor

Abstract

A communication control method according to one embodiment of the present invention is used in a mobile communication system having a user equipment and a base station device and implementing wireless communication between the user equipment and the base station device. In a communication control method, a first layer of a user equipment acquires slice information of a cell in which the user equipment exists, the slice information having been transmitted from a base station device, and the first layer of the user equipment reports the slice information to a second layer of the user equipment, the second layer being located at a higher layer than the first layer.

Description

[0001] This application is a divisional application of Chinese invention patent application filed on October 7, 2021, with application number 202180083264.6. Technical Field

[0002] This disclosure relates to a communication control method used in a mobile communication system. Background Technology

[0003] Network slicing (or network slice) has been defined in the standards of the 3rd Generation Partnership Project (3GPP), which is a standardization project for mobile communication systems (see, for example, non-patent literature 1).

[0004] Network slicing is a concept that allows for differentiated processing based on each customer's requirements. It's also a technology used to virtually slice a network to efficiently provide network services according to the needs of the services used by customers.

[0005] A network slice consists of portions of the Radio Access Network (RAN) and the Core Network (CN). Each network slice is identified by Single Network Slice Selection Auxiliary Information (S-NSSAI).

[0006] For example, network slices can be constructed for each service such as enhanced mobile broadband (eMBB: high speed and high capacity). This allows, for example, the network to provide users with network slices that match each service.

[0007] Note that in 3GPP, a technology is being investigated in which multiple different slices can be supported at different frequencies and multiple different slices can be supported at the same frequency in different regions (see, for example, non-patent literature 2).

[0008] Citation List

[0009] Non-patent literature

[0010] Non-patent document 1: 3GPP TS 38.300 V16.2.0 (2020-07)

[0011] Non-patent literature 2: 3GPP TR 38.832 V0.1.0 (2020-08) Summary of the Invention

[0012] In a first embodiment, the communication control method is a communication control method used in a mobile communication system, which includes a user equipment and a base station device, and is configured to perform wireless communication between the user equipment and the base station device. The communication control method includes: obtaining slice information of the cell in which the user equipment resides from a first layer of the user equipment, the slice information being transmitted from the base station device; and notifying the slice information from the first layer of the user equipment to a second layer of the user equipment, the second layer being higher than the first layer.

[0013] In a second embodiment, the communication control method is a communication control method used in a mobile communication system, which includes a user equipment and a base station device, and is configured to perform wireless communication between the user equipment and the base station device. The communication control method includes: notifying a planned slice from a second layer of the user equipment to a first layer of the user equipment, the second layer being higher than the first layer; and performing predetermined processing by the first layer of the user equipment.

[0014] In a third embodiment, the communication control method is a communication control method used in a mobile communication system, which includes a user equipment and a first base station device and a second base station device, and is configured to perform wireless communication between the user equipment and the first and second base station devices. The communication control method includes: the second base station device broadcasting slice information supported by the first base station device adjacent to the second base station device. The communication control method also includes: the user equipment acquiring the slice information supported by the first base station device.

[0015] In the fourth embodiment, the communication control method is a communication control method used in a mobile communication system, which includes user equipment and base station equipment, and is configured to perform wireless communication between the user equipment and the base station equipment. The communication control method includes: the base station equipment broadcasting cell reselection priorities for each network slice; and the user equipment performing cell reselection by using the cell reselection priorities.

[0016] In a fifth embodiment, the communication control method is a communication control method used in a mobile communication system, which includes user equipment and base station equipment, and is configured to perform wireless communication between the user equipment and the base station equipment. The communication control method includes: when the user equipment performs cell selection during RRC (Radio Resource Control) reconstruction, the user equipment preferentially selects a cell that supports a network slice that the user equipment had already accessed before the RRC reconstruction; and the user equipment accesses the selected cell. Attached Figure Description

[0017] Figure 1 This is a diagram illustrating a configuration example of a mobile communication system according to an embodiment.

[0018] Figure 2This is a diagram illustrating a configuration example of a user equipment according to an embodiment.

[0019] Figure 3 This is a diagram illustrating an example configuration of a base station apparatus according to an embodiment.

[0020] Figure 4 This is a diagram illustrating an example configuration of the protocol stack for the user plane of the radio interface.

[0021] Figure 5 This is a diagram illustrating an example configuration of the protocol stack for the control plane of a radio interface.

[0022] Figure 6 This is a diagram illustrating an example of the relationship between the AS layer and higher layers.

[0023] Figure 7(A) is a diagram illustrating an example of a mobile communication system, and Figure 7(B) is a diagram illustrating an operational example of Example 1.

[0024] Figures 8(A) and 8(B) are diagrams showing operational examples of Example 2 and Example 3, respectively.

[0025] Figure 9 This is a diagram illustrating an example of the operation in Example 4.

[0026] Figure 10(A) is a diagram illustrating an operational example of Example 5, and Figure 10(B) is a diagram illustrating an example of sending slice information.

[0027] Figure 11 This is a diagram illustrating an example of sending slice information.

[0028] Figures 12(A) and 12(B) are diagrams showing operational examples of Example 6 and Example 7, respectively.

[0029] Figure 13 This is a diagram illustrating an example of operation from Example 8.

[0030] Figure 14 This is a diagram illustrating an example of operation in Example 9. Detailed Implementation

[0031] A mobile communication system is described with reference to the accompanying drawings, according to an embodiment. In the description of the drawings, identical or similar parts are indicated by identical or similar reference numerals.

[0032] Configuration of mobile communication system

[0033] First, in the embodiments, a configuration example of the mobile communication system is described. Although the mobile communication system in the embodiments is a 3GPP 5G system, Long Term Evolution (LTE) can be applied at least partially to the mobile communication system. Application to future wireless communication systems such as 6G is also possible.

[0034] Figure 1 This is a diagram illustrating a configuration example of a mobile communication system 1 according to an embodiment.

[0035] like Figure 1 As shown, the mobile communication system 1 includes a user equipment (UE) 100 and a 5G radio access network (NG-RAN) 10.

[0036] UE 100 is a mobile device. UE 100 can be any device, as long as it is used by a user. Examples of UE 100 include devices capable of performing wireless communication, such as mobile phone terminals (including smartphones), tablet terminals, laptop PCs, communication modules (including communication cards or chipsets), sensors, devices mounted on sensors, vehicles, devices mounted on vehicles (vehicle UE), flying objects, and devices mounted on flying objects (airborne UE).

[0037] NG-RAN 10 includes base station installations (hereinafter, in some cases, also referred to as "base stations") 200-1 to 200-3, which are referred to as "gNBs" ("Next Generation Node Bs") in the 5G system. gNBs 200-1 to 200-3 can also be referred to as NG-RAN nodes. gNBs 200-1 to 200-3 are interconnected via the Xn interface, which serves as an inter-base station interface. Each of gNBs 200-1 to 200-3 manages one or more cells. Each gNB 200-1 to 200-3 performs wireless communication with UE 100, which has established connections with its own cells. Each of gNBs 200-1 to 200-3 has radio resource management (RRM) functions, functions for routing user data (hereinafter referred to as "data"), and / or measurement control functions for mobility control and scheduling, etc. "Cell" is used as a term to represent the smallest unit of a wireless communication area. "Cell" is also used as a term to refer to functions or resources used to perform wireless communication with UE 100. A cell belongs to a carrier frequency. Note that in this embodiment, "cell" and "base station device" or "cell" and "gNB" can be used without distinguishing between them.

[0038] Note that gNBs 200-1 to 200-3 can connect to the Evolved Packet Core (EPC), which is the core network of LTE, and / or LTE base stations can connect to 5GC 20. LTE base stations can connect to gNBs 200-1 to 200-3 via inter-base station interfaces.

[0039] 5GC 20 includes Access and Mobility Management Functions (AMF) and User Plane Functions (UPF) 300. AMF performs various types of mobility control for UE 100. AMF manages information about the area where UE 100 exists by communicating with UE 100 using Non-Access Stratum (NAS) signaling. UPF controls data transmission. AMF and UPF 300 are connected to gNB 200-1 to 200-3 via the NG interface, which is the interface between the base station and the core network.

[0040] Note that in the following description, gNB 200-1 to 200-3 may be referred to as gNB 200. AMF and UPF 300's AMF may be referred to as AMF 300.

[0041] Figure 2 This is a diagram illustrating the configuration of UE 100 (User Equipment) according to an embodiment.

[0042] like Figure 2 As shown, UE 100 includes receiver 110, transmitter 120 and controller 130.

[0043] Receiver 110 performs various types of reception under the control of controller 130. Receiver 110 includes an antenna and receiving equipment. The receiving equipment converts (down-converts) the radio signals received through the antenna into baseband signals (received signals) and outputs the resulting signals to controller 130.

[0044] Transmitter 120 performs various types of transmissions under the control of controller 130. Transmitter 120 includes an antenna and a transmitting device. The transmitting device converts (up-converts) the baseband signal (transmit signal) output by controller 130 into a radio signal and transmits the resulting signal through the antenna.

[0045] Controller 130 performs various types of control within UE 100. Controller 130 includes at least one processor and at least one memory electrically connected to the processor. The memory stores programs to be executed by the processor, as well as information to be processed by the processor. The processor may include a baseband processor and a central processing unit (CPU). The baseband processor performs modulation and demodulation, encoding and decoding, etc., of baseband signals. The CPU executes programs stored in the memory, thereby performing various types of processing. The CPU may be replaced by a processor or controller, such as a digital signal processor (DSP) or a field-programmable gate array (FPGA). In this embodiment, controller 130 may perform various types of control or processing as described in the following examples.

[0046] Figure 3 This is a diagram illustrating the configuration of a gNB 200 (base station) according to an embodiment.

[0047] like Figure 3 As shown, the gNB 200 includes a transmitter 210, a receiver 220, a controller 230, and a backhaul communicator 240.

[0048] Transmitter 210 performs various types of transmissions under the control of controller 230. Transmitter 210 includes an antenna and a transmitting device. The transmitting device converts (up-converts) the baseband signal (transmit signal) output by controller 230 into a radio signal and transmits the obtained signal through the antenna.

[0049] Receiver 220 performs various types of reception under the control of controller 230. Receiver 220 includes an antenna and receiving equipment. The receiving equipment converts (down-converts) the radio signals received through the antenna into baseband signals (received signals) and outputs the resulting signals to controller 230.

[0050] Controller 230 performs various types of control over gNB 200. Controller 230 includes at least one processor and at least one memory electrically connected to the processor. The memory stores programs to be executed by the processor, as well as information to be processed by the processor. The baseband processor performs modulation and demodulation, encoding and decoding of baseband signals, etc. The CPU executes programs stored in the memory, thereby performing various types of processing. Instead of a CPU, a processor or controller such as a DSP or FPGA can be used. In this embodiment, controller 230 can perform various types of control or processing as described in the following examples.

[0051] The backhaul communicator 240 is connected to adjacent base stations via an inter-base station interface. The backhaul communicator 240 is connected to each node of the 5GC 20 via an interface between the base station and the core network. Note that the gNB 200 may include a central unit (CU) and distributed units (DU) (i.e., functions are divided), and these two units can be connected via an F1 interface.

[0052] Protocol stack in radio interface

[0053] Figure 4 This is a diagram illustrating the configuration of the protocol stack for the user plane radio interface that processes data.

[0054] like Figure 4 As shown, the user plane radio interface protocol includes the physical (PHY) layer, media access control (MAC) layer, radio link control (RLC) layer, packet data convergence protocol (PDCP) layer, and service data adaptation protocol (SDAP) layer.

[0055] The PHY layer performs encoding and decoding, modulation and demodulation, antenna mapping and demapping, and resource mapping and demapping. Data and control information are transmitted between the PHY layer of UE 100 and the PHY layer of gNB 200 via physical channels.

[0056] The MAC layer performs data priority control, retransmission processing using Hybrid ARQ (HARQ), random access procedures, etc. Data and control information are transmitted between the MAC layer of UE 100 and the MAC layer of gNB 200 via the transport channel. The MAC layer of gNB 200 includes a scheduler. The scheduler determines the transmission format (transport block size, modulation and coding scheme (MCS)) in the uplink and downlink and the resource blocks to be allocated to UE 100.

[0057] The RLC layer transmits data to the receiving RLC layer using the functions of the MAC and PHY layers. Data and control information are transmitted between the RLC layer of UE 100 and the RLC layer of gNB 200 via logical channels.

[0058] The PDCP layer performs header compression and decompression, as well as encryption and decryption.

[0059] The SDAP layer performs the mapping between IP flows, which act as the core network's QoS control unit, and radio bearers, which act as the access layer (AS)'s QoS control unit. Note that SDAP may not be provided when the RAN is connected to the EPC.

[0060] Figure 5 This is a diagram illustrating the configuration of the protocol stack for the radio interface of the control plane that processes signaling (control signals). (See diagram for example.) Figure 5 As shown, the protocol stack of the control plane's radio interface includes a Radio Resource Control (RRC) layer and a Non-Access Stratum (NAS) layer, instead of... Figure 4 The SDAP layer is shown.

[0061] RRC signaling for various configurations is transmitted between the RRC layer of UE 100 and the RRC layer of gNB 200. The RRC layer controls logical channels, transport channels, and physical channels based on the establishment, reconstruction, and release of radio bearers. When a connection exists between the RRC of UE 100 and the RRC of gNB 200 (RRC connection), UE 100 is in an RRC connected state. When a connection does not exist between the RRC of UE 100 and the RRC of gNB 200 (RRC connection), UE 100 is in an RRC idle state. When the RRC connection is suspended, UE 100 is in an RRC inactive state.

[0062] The NAS layer, which is above the RRC layer, performs session management, mobility management, etc. NAS signaling is transmitted between the NAS layer of UE 100 and the NAS layer of AMF300.

[0063] Note that UE 100 includes the application layer in addition to the radio interface protocol.

[0064] Operation Example

[0065] Next, we will describe some operation examples. The operation examples will be described in the following order.

[0066] (Example 1) In UE 100, the slice information of the cell where UE 100 exists is notified from the AS layer to the higher layers (NAS, etc.).

[0067] (Example 2) In UE 100, the higher layer notifies the AS layer of the expected slice.

[0068] (Example 3) In UE 100, the AS layer searches for and reselects cells that support the expected slice notified from higher layers.

[0069] (Example 4) UE 100 notifies gNB 200 of the expected slice.

[0070] (Example 5) Cell broadcast (or notification) slice information supported by neighboring cells.

[0071] (Example 6) gNB 200-1 notifies the neighboring gNB 200-2 of the slice information supported by gNB 200-1.

[0072] (Example 7) The AMF 300 notifies the gNB 200 of slice information supported by neighboring cells.

[0073] (Example 8) The serving cell broadcasts (or notifies) the cell reselection priority for each slice.

[0074] (Example 9) In cell selection during RR reconstruction, UE 100 prioritizes the cells supported by the slice that UE 100 is accessing.

[0075] Example 1

[0076] Figure 6 This is a diagram illustrating an example of the relationship between AS layer 140 and higher layer 150 in UE 100. (See diagram for example.) Figure 6 As shown, UE100 includes an AS layer 140 and a higher layer 150 above the AS layer 140.

[0077] AS level 140 and high level 150 include Figure 5The control plane layers of the radio interface are shown. In other words, AS layer 140 includes the PHY layer, MAC layer, RLC layer, PDCP layer, and RRC layer. Higher layer 150 includes the NAS layer. In Example 1, as... Figure 6 As shown, AS layer 140 notifies higher layer 150 of slice information related to the network slice of the cell where UE 100 resides. Such processing can be performed, for example, in controller 130. Note that, in the following text, network slice may be referred to as "slice".

[0078] Figure 7(A) is a diagram illustrating an example where UE 100 exists in cell #1 of gNB 200. In this case, UE 100 notifies the higher layer 150 of the slice information of cell #1 in which UE 100 exists from AS layer 140.

[0079] Slicing information is processed at the NAS layer and managed, for example, in AMF 300. On the other hand, cell-related information is processed at AS layer 140. When AS layer 140 in UE 100 receives the slice information for cell #1, AS layer 140 notifies the higher layer 150 of the slice information, so that the higher layer 150 (or NAS layer) can have access to the slice information for each cell.

[0080] Figure 7(B) is a diagram illustrating an example of operation in Example 1.

[0081] In step S100, the UE 100, which is in an idle or inactive state, obtains slice information related to the slices supported in the cell of the gNB200 where the UE 100 exists (cell #1 in the example of FIG7(A)).

[0082] Slice information can be included in a System Information Block (SIB) and broadcast, or it can be included in an RRC message and sent to UE 100. Slice information may include S-NSSAI, or it may include a human-readable identifier such as "eMBB". UE 100 in RRC connected state can receive slice information.

[0083] In step S101, AS layer 140 notifies higher layer 150 of the slice information. Examples of triggering the AS layer 140 to notify higher layer 150 include the following.

[0084] Specifically, when a UE 100 in an idle or inactive state performs cell selection or cell reselection, AS layer 140 can notify higher layers 150 of slice information. When a handover is performed in a UE 100 in an RRC connected state, AS layer 140 can notify higher layers 150 of slice information. AS layer 140 can issue a notification when the slice information supported by the cell changes. AS layer 140 can issue a notification when the previously notified slice information differs from the current slice information (or the slice information currently obtained from gNB 200). AS layer 140 can issue notifications periodically (or at a constant period).

[0085] In step 102, the upper layer 150 performs a predetermined process. For example, the predetermined process includes the following.

[0086] Specifically, higher layer 150 can notify the application layer of currently supported slice information. In this case, higher layer 150 can select supported slice information from one or more slice information notified in step S101 and notify the selected slice information. Higher layer 150 (or controller 130) can display slice coverage information on the display of UE 100. As slice coverage information, for example, a supported service name such as "5G URLLC" can be displayed next to the antenna marker on the display. Slice coverage information can be displayed in the settings bar. Higher layer 150 can notify AS layer 140 of the expected slice. The above details are described in Example 2.

[0087] Example 2

[0088] Example 2 is an example of the upper layer 150 of UE 100 notifying the AS layer 140 of the expected slice.

[0089] The anticipated slice can be a slice expected to be used in UE 100, a candidate slice, or a desired slice. For example, notifying AS layer 140 of such a slice at higher level 150 allows AS layer 140 to perform various processes, such as cell reselection.

[0090] Figure 8(A) is a diagram illustrating an example of operation in Example 2.

[0091] In step S110, the upper layer 150 notifies the AS layer 140 of the expected slice.

[0092] The expected slice to be notified can be in the form of a list of multiple expected slices. In this case, for example in UE100, there can be multiple slices used (or requested) by an installed or active application, and these slices can be in the form of a list. For example, there can be multiple expected slices licensed (or certified) by a CN, and these slices can be in the form of a list.

[0093] When multiple expected slices exist, the priority of each expected slice can be further notified. Higher layer 150 can instruct AS layer 140 to search for expected slices using methods such as cell reselection. The details above are described in Example 3. When higher layer 150 receives a query (such as an information provision request) from AS layer 140, higher layer 150 can notify AS layer 140 of the expected slice. In this case, AS layer 140 can query higher layer 150 about the expected slice, for example, during cell reselection or when changing the slice information supported by the cell.

[0094] Note that expected slices can be created in upper layer 150. Expected slices can be sent from AMF 300 to upper layer 150.

[0095] In step 111, AS layer 140 performs a predetermined process. For example, the predetermined process includes the following.

[0096] Specifically, AS layer 140 can check whether the notified expected slice is supported in the cell where UE 100 is located. In this case, AS layer 140 can notify the NAS layer (or higher layer 150) of "IN" (if supported) or "OUT" (if not supported). In UE 100 in an idle or inactive state, when the notified expected slice is not supported in the cell where UE 100 is located, AS layer 140 can perform cell reselection. The above details are described in Example 3. On the other hand, in UE 100 in an RRC connected state, when the notified expected slice is not supported in the cell where UE 100 is located, AS layer 140 can send the expected slice to gNB 200. The above details are described in Example 4.

[0097] Example 3

[0098] Example 3 is an example of AS layer 140 searching for cells that support the expected slice notified from higher layer 150 and performing cell reselection in UE 100 which is in an idle or inactive state.

[0099] For example, by searching and reselecting such cells, UE 100 can access a slice that provides the services that UE 100 desires, and receive such services via the accessed slice.

[0100] Figure 8(B) is a diagram showing an example of operation in Example 3.

[0101] In step S120, the expected slice is notified from the upper layer 150 to the AS layer 140.

[0102] In step S121, the AS layer 140 in cells that do not support the notified expected slice performs cell reselection processing.

[0103] When a cell search is instructed from the NAS layer, the AS layer 140 can perform cell reselection processing. For example, in step S120, such an instruction can be notified along with the expected slice. During cell reselection processing, the AS layer 140 can prioritize reselecting (or selecting) cells that support the expected slice. In this case, for example, the AS layer 140 attempts to select a cell with the best radio quality (such as RSRP (Reference Signal Received Power)) from the cells (ranked) that support the expected slice. If such a cell does not exist, the AS layer 140 reselects a cell that does not support the expected slice. For example, the AS layer 140 performs cell reselection with the highest priority on cells and / or frequencies that support the expected slice. In this case, priority can be changed by reselection priority processing. The AS layer 140 can notify the NAS layer whether the cell search for the expected slice was successful. In this case, for example, the AS layer 140 can only notify of success or failure. For example, the AS layer 140 can notify the slice information of the cell after reselection.

[0104] Example 4

[0105] Example 4 illustrates UE 100 sending a desired slice to gNB 200. For instance, the slice supported in the cell where UE 100 resides may not be the slice UE 100 expects, and UE 100 may expect a different slice. In this case, UE 100 sends the desired slice to gNB 200 at an appropriate timing. For example, this allows gNB 200 to switch UE 100 to a cell that supports the slice expected by UE 100, enabling UE 100 to receive the desired service. Note that, as an example of the pre-processing in Example 2 (step S111 in Figure 8(A)), UE 100 can send a desired slice to gNB 200.

[0106] Figure 9 This is a diagram illustrating an example of the operation in Example 4.

[0107] In step S130, UE 100, which is in an RRC connection state with gNB 200, sends the expected slice to gNB 200. For example, the trigger for sending the expected slice may be the following.

[0108] Specifically, when AS layer 140 of UE 100 receives a notification of an expected slice from higher layer 150, UE 100 (or AS layer 140) can send the expected slice to gNB 200. When the slice accessed by UE 100 changes (or has changed), UE 100 can send the expected slice to gNB 200. The phrase "when the expected slice changes" indicates situations such as when the initial connection of an RRC connection occurs, or when the content of the last sent expected slice notification is available. When UE 100 is provided with information from gNB 200 (or receives a query), for example, when UE 100 receives a request from gNB 200, UE 100 can send the expected slice to gNB 200. When a handover is anticipated (or performed), for example, when a measurement report is triggered, UE 100 can send the expected slice to gNB 200. If the gNB 200 is pre-licensed (configured) in advance, a notification can be made.

[0109] However, these transmission triggers may have the following limitations, for example. Specifically, UE 100 may send the expected slice to gNB 200 only when the slice supported by the cell (where UE 100 exists) does not match the expected slice (or when UE 100 expects a slice that it does not support). In this case, for example, the expected slice may be sent to prompt gNB 200 to perform a handover to a cell that supports the slice expected by UE 100. UE 100 may also send the expected slice to gNB 200 only when the slice supported by the cell matches the expected slice (or supports all expected slices). In this case, for example, when UE 100 enters (or selects or switches to) a cell that supports the desired slice, the expected slice may be sent to gNB 200.

[0110] For example, the content of the message sent in step S130 could be as follows. Specifically, UE 100 could send slice information representing expected slices in the form of a list to gNB 200. Such slice information could include all expected slices in UE 100 and could be sent. The slice information could (only) include expected slices that match the slices supported by the cell, or it could (only) include expected slices that do not match the slices supported by the cell.

[0111] For example, the message sent in step S130 could be the following. Specifically, UE 100 could include the expected slice in the UE assistance information message to be sent to gNB 200. In this case, UE 100 could include information such as the expected slice (a list), priority (or whether it is expected to be prioritized), and whether it is expected to access the slice (or the expected slice) within a specific time period (in the future). UE 100 could also include the expected slice in the measurement report message to be sent to gNB 200. In this case, UE 100 could send a measurement report message in which the measurement results of each cell are associated with the expected slice, including the slice information supported by the cell, whether it matches (or does not match) the expected slice of UE 100, and the preference of UE 100 (indicating the preference of "targeting this cell if possible").

[0112] In step S131, gNB 200 performs a predetermined process for UE 100. For example, the predetermined process may include the following.

[0113] Specifically, when the expected slice is not supported in the cell where UE 100 resides, gNB 200 can switch UE 100 to a cell that supports the expected slice. For example, this handover allows UE 100 to receive the desired service from a cell that supports the expected slice. gNB 200 can send information to UE 100 indicating that the expected slice is not supported in the area (or cell). In this case, this can be sent by gNB 200 to UE 100 when the expected slice is not supported in any neighboring cells.

[0114] Example 5

[0115] Example 5 is an example of cell broadcasting or sending slice information supported by neighboring cells.

[0116] For example, when performing cell reselection as described in Example 3, UE 100 can search for cells across all supported frequencies and read SIBs to confirm the slices supported for each cell. In this case, UE 100 confirms the slices supported for each cell, thus increasing power consumption.

[0117] For example, gNB 200 broadcasts slice information of neighboring cells. This allows UE 100 to obtain slice information of neighboring cells, which eliminates the need to confirm slices of neighboring cells during cell search, thereby reducing power consumption.

[0118] Figure 10(A) is a diagram showing an example of operation in Example 5.

[0119] In step S140, gNB 200 (including the serving cell of UE 100) broadcasts slice information supported by neighboring cells.

[0120] Figure 10(B) and Figure 11 Figures 10(B) illustrate examples of the relationship between the serving cell and neighboring cells. In Figure 10(B), UE 100 is located in cell #1 of gNB 200, and cell #1 is the serving cell. In this case, gNB 200 broadcasts slice information supported by cell #2, which is adjacent to cell #1. Figure 11 In this context, cell #1 of gNB 200-1 is the serving cell of UE100, and cell #2 of gNB 200-2, which is adjacent to gNB 200-1, is a neighboring cell near cell #1. gNB 200-1 broadcasts the slice information of cell #2 of gNB 200-1.

[0121] Note that when CA (carrier aggregation) or DC (dual connectivity) is not configured, the primary cell is the serving cell for UE 100 in RRC connected state. When CA or DC is configured, the serving cell is used for UE 100 in RRC connected state to represent a set of cells including the specific cell and all secondary cells.

[0122] The gNB 200 broadcasts slice information using SIB. However, the gNB 200 can also send slice information supported by neighboring cells via dedicated signaling. Examples of dedicated signaling may include RRC reconfiguration messages used when RRC connectivity changes. The gNB 200 may broadcast supported slice information in association with a cell ID (identifier) ​​(and / or gNB ID). The gNB 200 may broadcast slice information in association with information about guaranteed service requirements. For example, examples of service requirement information may include the following.

[0123] Specifically, for eMBB, service requirement information includes maximum and / or average throughput (or bit rate), etc. For URLLC (Ultra-Reliable and Low-Latency Communication), service requirement information includes maximum latency, maximum packet loss, or synchronization (or reference) clock accuracy, etc. For mMTC (Massive Machine-Type Communication), service requirement information includes maximum number of connections, remaining capacity (allowed remaining connections), etc. Service requirement information can be indicated by supported 5QIs (5G QoS (Quality of Service) Indicators) (or QoS information). For example, service requirement information can be information about the highest QoS level and the highest QoS bearer supported, indicated by 5QIs.

[0124] Referring back to Figure 10(A), in step S141, UE 100 obtains slice information of neighboring cells and performs predetermined processing. For example, the predetermined processing may include the following.

[0125] Specifically, UE 100 can perform the cell reselection process described in Example 3. UE 100 can notify gNB 200. When AS layer 140 in UE 100 reselects a cell that does not support the expected slice, AS layer 140 can notify higher layers 150 of the slice information of neighboring cells. In this case, for example, higher layers (application layer, etc.) 150 can display a warning on the display (to the user) that the slice is outside the coverage area.

[0126] Example 6

[0127] Example 6 is an example of gNB 200-1 sending slice information supported by gNB 200-1 to the neighboring gNB 200-2.

[0128] Example 5 describes an example of a serving cell (or gNB 200) performing actions such as broadcasting slice information for neighboring cells. gNB 200-1 sends slice information supported by gNB 200-1 to the neighboring gNB 200-2. This allows the neighboring gNB 200-2 to perform actions such as broadcasting slice information from gNB 200-1 for neighboring cells of gNB 200-2. UE 100 can obtain the slice information of gNB 200-1 from gNB 200-2.

[0129] Figure 12(A) is a diagram showing an example of operation in Example 6.

[0130] In step S150, gNB 200-1 sends the slice information supported by gNB 200-1 to the adjacent gNB 200-2.

[0131] In this scenario, gNB 200-1 can send slice information associated with each cell managed by gNB 200-1 to the neighboring gNB 200-2. gNB 200-1 can send this information to the neighboring gNB 200-2 via Xn-AP (Application Protocol) signaling (or via Xn-AP messages). Xn-AP is the application protocol in the control plane of the Xn interface between base stations. gNB 200-1 can send slice information to the neighboring gNB 200-2 under the following triggers.

[0132] Specifically, when establishing an Xn connection, gNB 200-1 can send slice information to the neighboring gNB 200-2. When the supported slices change (or when the configuration of gNB 200-1 changes), gNB 200-1 can send slice information to the neighboring gNB 200-2. When gNB 200-1 receives a request for slice information from a neighboring cell (or neighboring gNB 200-2), gNB 200-1 can send slice information to the neighboring gNB 200-2. gNB 200-1 can periodically (or at a constant period) send slice information to the neighboring gNB 200-2.

[0133] In step S151, gNB 200-1 performs predetermined processing based on the slice information. Predetermined processing may include, for example, updating the slice information of neighboring cells or performing mobility control. An example of mobility control is the handover process of UE100 described above.

[0134] Example 7

[0135] Example 7 is an example of the AMF 300 sending slice information supported by neighboring cells to the gNB 200.

[0136] Example 6 or other examples describe obtaining slice information supported by neighboring cells from a neighboring gNB 200-1. Example 7 describes an example of gNB 200 obtaining this information from AMF 300. For example, this allows gNB 200 to perform, for instance, the broadcasting of slice information supported by neighboring cells as described in Example 5.

[0137] Figure 12(B) is a diagram showing an example of operation in Example 7.

[0138] In step S160, AMF 300 sends the slice information supported by (neighboring) gNB 200-2, which belongs to AMF 300, to gNB 200-1, which belongs to AMF 300. Figure 11 In the example, cell #2 of gNB 200-2 is a "neighboring cell" of cell #1 of gNB 200-1. In this case, AMF 300 will send slice information supported by cell #2 (or gNB 200-2) to gNB 200-1.

[0139] The AMF 300 can send slice information of neighboring cells to the gNB 200 via NG-AP signaling (or via NG-AP messages). The triggering of the AMF 300 sending slice information can be the same as the triggering of the gNB 200-1 sending slice information in Example 6. In other words, the AMF 300 can send slice information when an NG connection is established, when a slice supported by a gNB 200 subordinate to the AMF 300 changes, when it receives a request for slice information from a neighboring gNB 200-2 subordinate to the AMF 300, or it can send it periodically.

[0140] Note that the AMF 300 can be configured with slice information supported by neighboring cells, for example, through Operations Management and Maintenance (OAM).

[0141] In step S161, gNB 200 performs a pre-defined process. This pre-defined process can be the same as the pre-defined process performed by the neighboring gNB 200-2 that received the slice information, as described in Example 6. In other words, gNB 200 can update the slice information supported by neighboring cells, or it can perform mobility control such as handover procedures for UE 100. AMF 300 can inform gNB 200 of the slice information supported by AMF 300 itself (or the network managed by AMF 300 itself). This allows gNB 200 to appropriately select the AMF 300 (or the core network) supporting the intended slice for UE 100 (or perform data routing for UE 100).

[0142] Example 8

[0143] Example 8 is an example of broadcasting or sending the cell reselection priority for each (expected) slice.

[0144] UE 100 performs cell reselection based on the cell reselection priority configured by the cell. However, this may not allow UE 100 to reliably select a cell that supports the expected slice.

[0145] On the other hand, the selection of cells supporting the expected slice can also be controlled based on a dedicated priority (configured via RRC). However, when UE 100 moves to another area (or cell) or when UE 100's expected slice changes, UE 100 may disadvantageously not select a cell supporting the expected slice.

[0146] It is also conceivable that UE 100 can perform cell reselection, prioritizing cells or frequencies that support the desired slice. However, in this case, which cell is selected depends on the implementation of UE 100. Therefore, control from the network side is not possible.

[0147] The gNB 200 performs tasks such as broadcasting cell reselection priorities for each slice. For example, this allows UE 100 to perform cell reselection using cell reselection priorities specified by the network side. Therefore, access to cells in the intended slice supporting UE 100 can be achieved while simultaneously implementing network control.

[0148] Figure 13 This is a diagram illustrating an example of operation from Example 8.

[0149] In step S170, gNB 200 broadcasts or transmits the cell reselection priority for each slice. gNB 200 can broadcast the cell reselection priority for each slice using SIB. gNB 200 can also transmit the cell reselection priority for each slice to UE 100 via dedicated signaling such as an RRC release (RRCRelease) message.

[0150] The gNB 200 can broadcast the slice information described in Example 6 in association with (or in conjunction with) cell reselection priorities (or priority information) for cells and / or frequencies. For example, in the case of frequency priority, a UE 100 anticipating (or desiring) an eMBB slice can use priority "7" for frequency f1, priority "3" for frequency f2, etc., and a UE 100 anticipating (or desiring) a URLLC slice can use priority "7" for frequency f2, priority "3" for frequency f1, etc. Similarly, in the case of cell priority, a UE 100 anticipating (or desiring) an eMBB slice can use priority "7" for cell #1, priority "3" for cell #2, etc. In these examples, it is also possible for a larger number to indicate higher priority, but a smaller number to indicate higher priority.

[0151] Note that gNB 200 can also broadcast cell reselection priorities (related to relevant technologies) that are not associated with slice information. In this case, the reselection priorities to be broadcast can be used in legacy UEs (such as Rel-15 in 3GPP) or UE 100s that do not have the expected slice.

[0152] In step S171, UE 100 applies a cell reselection priority based on the expected slice of UE 100 and performs cell reselection. In this case, AS layer 140 of UE 100 can select the cell reselection priority to apply from the broadcast cell reselection priorities by using the expected slice notified from higher layer 150. In this case, when multiple expected slices exist, AS layer 140 can select the cell reselection priority corresponding to the expected slice with the highest slice priority notified from higher layer 150.

[0153] Example 9

[0154] Example 9 is an example of how UE 100 prioritizes selecting the cell that supports the slice that UE 100 is accessing during RRC rebuilding.

[0155] When a radio link failure (RLF) occurs while UE 100 is accessing a slice in an RRC-connected state, UE 100 performs an RRC reconstruction procedure. During the RRC reconstruction, cell selection is performed. If UE 100 selects a cell that does not support the slice that UE 100 already accessed before the RRC reconstruction, access to the slice may be lost.

[0156] In Example 9, UE 100 prioritizes cells that support the slices that UE 100 has already accessed before RRC reconstruction during cell selection, thereby reducing the occurrence of slice access drops. This allows UE 100 to receive continuous service provision.

[0157] Figure 14 This is a diagram illustrating an example of operation in Example 9.

[0158] In step S180, UE 100 and gNB 200 are connected to each other in an RRC connection to be in an RRC connection state.

[0159] In step S181, UE 100 and gNB 200 perform data communication.

[0160] In step S182, a failure occurs in the radio link.

[0161] In step S183, UE 100 initiates the RRC reconstruction process to send an RRC reconstruction request message to gNB 200.

[0162] In step S184, UE 100 performs cell selection processing. UE 100 uses RRC reconstruction as a trigger to perform cell selection. In this case, UE 100 prioritizes cells that support the slice that UE 100 has already accessed before the RRC reconstruction. In other words, UE 100 can be allowed to prioritize (or select) cells that support the slice that UE 100 accesses. UE 100 can perform cell selection processing based on the expected slice notified from the higher layer 150. UE 100 can perform cell selection processing by using slice information of neighboring cells provided from the (old) serving cell (e.g., Example 5). UE 100 can obtain slice information provided by the SIB to check the slice information supported for each neighboring cell during cell search.

[0163] In step S185, UE 100 receives an RRC reconstruction request message.

[0164] In step S186, UE 100 sends an RRC reconstruction complete message.

[0165] In step S187, UE 100 establishes an RRC connection with the cell (gNB 200 with the cell) selected in step S184.

[0166] In step S188, UE 100 accesses the selected cell (gNB 200 with the selected cell) and performs data communication with that cell. UE 100 can continuously access the slices that UE 100 has already accessed before the radio link failure (step S182), and can receive continuous service provision through the slices.

[0167] Other embodiments

[0168] A program may be provided that enables the computer to execute each procedure performed by the UE 100 or gNB 200. The program may be recorded on a computer-readable medium. The use of a computer-readable medium allows the program to be installed on the computer. Here, the computer-readable medium on which the program is recorded may be a non-transitory recording medium. There are no particular limitations on the non-transitory recording medium, and it may be, for example, a recording medium such as a CD-ROM or DVD-ROM.

[0169] Circuitry for performing the processing to be performed by UE 100 or gNB 200 may be integrated, and at least a portion of UE 100 or gNB 200 may be configured as a semiconductor integrated circuit (chipset or SoC).

[0170] Although embodiments have been described in detail with reference to the accompanying drawings, the specific configuration is not limited to the above configuration, and various design modifications can be made without departing from the spirit of the work. All or some examples can be combined as long as the overall composition remains consistent.

[0171] This application claims priority to Japanese Patent Application No. 2020-171978 (filed on October 12, 2020), the contents of which are incorporated herein by reference in their entirety.

[0172] List of reference numerals

[0173] 1: Mobile communication system

[0174] 10: NG-RAN

[0175] 20: 5GC

[0176] 100: UE

[0177] 110: Receiver

[0178] 120: Transmitter

[0179] 130: Controller

[0180] 140: AS layer

[0181] 150: High-level

[0182] 200 (200-1 to 200-3): gNB

[0183] 210: Transmitter

[0184] 220: Receiver

[0185] 230: Controller

[0186] 240: Backhaul Communicator

[0187] 300: AMF.

Claims

1. A communication control method, comprising: The user equipment stores identification information provided by the core network equipment to the user equipment for identifying multiple network slices, as well as priority information indicating the slice priority of the multiple network slices; The user equipment receives system information from the base station, and the system information indicates the correspondence between network slices and cell reselection priorities; The user equipment performs cell reselection. The cell reselection process includes the user equipment performing the cell reselection by using the cell reselection priority corresponding to the network slice indicated by the system information received from the base station and the priority information provided by the core network equipment.

2. A user equipment, comprising: The memory stores identification information provided by the core network device to the user equipment for identifying multiple network slices, and priority information indicating the slice priority of the multiple network slices; The receiver receives system information from the base station, the system information indicating the correspondence between network slices and cell reselection priorities; as well as The controller performs cell reselection. The controller performs the cell reselection by using the cell reselection priority corresponding to the network slice indicated by the system information received from the base station and the priority information provided by the core network equipment.

3. A processor for controlling user equipment, the processor performing the following processes: Store identification information provided by the core network device to the user equipment for identifying multiple network slices, and priority information indicating the slice priority of the multiple network slices; System information is received from the base station, the system information indicating the correspondence between network slices and cell reselection priorities; as well as Perform cell reselection. The cell reselection process includes the following steps: performing the cell reselection by using the cell reselection priority corresponding to the network slice indicated by the system information received from the base station and the priority information provided by the core network device.

4. A program that causes a user equipment to perform the following processes: Store identification information provided by the core network device to the user equipment for identifying multiple network slices, and priority information indicating the slice priority of the multiple network slices; System information is received from the base station, the system information indicating the correspondence between network slices and cell reselection priorities; as well as Perform cell reselection. The cell reselection process includes the following steps: performing the cell reselection by using the cell reselection priority corresponding to the network slice indicated by the system information received from the base station and the priority information provided by the core network device.

5. A mobile communication system comprising the user equipment and base station as described in claim 2.

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