Base station, and connection method

Abstract

To provide an appropriate service to a user device without changing wireless connection with the user device.SOLUTION: A base station according to one aspect is a base station 200 capable of wirelessly communicating with a user device 100. The base station 200 includes a first wireless unit 211 and a second wireless unit 221 capable of wirelessly communicating with the user device 100. The base station 200 further includes a first distribution unit 212 including a first scheduler 213 for a first service. The base station 200 further includes a second distribution unit 222 including a second scheduler 223 for a second service which is different from the first service. The base station 200 includes a control unit 250 which controls the first distribution unit and the second distribution unit. The base station 200 further includes a switching unit 260 which connects one of the first wireless unit 211 and the second wireless unit 221 wirelessly connected to the user device 100, to a distribution unit selected by the control unit 250 from among the first distribution unit 212 and the second distribution unit 222.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a base station and a connection method.

Background Art

[0002] In some regions, the operation of the 5th Generation (5G) mobile communication system (hereinafter sometimes referred to as the "5G system") has started. The 3rd Generation Partnership Project (3GPP) defines three types of performance requirements for the 5G system, namely enhanced Mobile Broad Band (eMBB), Ultra-Reliable and Low Latency Communications (URLLC), and massive Machine Type Communications (mMTC). By imposing such performance requirements on the 5G system, for example, it becomes possible to construct a 5G system that can support various use cases (or services).

[0003] In the 5G system, there is a base station called a gNB (next generation Node B). A configuration in which a plurality of gNB-DUs (Distributed Units) are connected to one gNB-CU (Central Unit) is allowed for the gNB. With such a configuration, for example, functions can be separated between the gNB-CU and the gNB-DU, and processing delays and the like can be prevented.

[0004] In addition, in a 5G system, it is possible to provide a QoS (Quality of Service) service at the IP flow level to a user equipment (UE). In a 5G system, a QoS flow is established during the establishment (PDU Session Establishment) or update (PDU Session Modification) of a PDU (Protocol Data Unit) session. The QoS flow is established between the user equipment (UE) and the UPF (User Plane Function) under the control of the SMF (Session Management Function). The user equipment can receive QoS services for each QoS flow.

Prior Art Documents

Non-Patent Documents

[0005]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Non-Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0006] One aspect of the present invention is to provide a base station and a connection method that can provide appropriate services to a user equipment without changing the radio connection with the user equipment.

Means for Solving the Problems

[0007] The base station according to the first aspect is a base station capable of wireless communication with a user equipment. The base station includes a first radio unit and a second radio unit capable of wireless communication with the user equipment. Further, the base station includes a first distributed unit including a first scheduler for a first service and a second distributed unit including a second scheduler for a second service different from the first service. Furthermore, the base station includes a control unit that controls the first distributed unit and the second distributed unit. Furthermore, the base station includes a switching unit that connects either one of the first radio unit and the second radio unit that is wirelessly connected to the user equipment and the distributed unit selected by the control unit among the first distributed unit and the second distributed unit.

[0008] The base station according to the second aspect is a base station capable of wireless communication with a user equipment. The base station includes a first radio unit and a second radio unit capable of wireless communication with the user equipment. Further, the base station includes a first distributed unit including a first scheduler for a first service and a second distributed unit including a second scheduler for a second service different from the first service. Furthermore, the base station includes a control unit that controls the first distributed unit and the second distributed unit. Furthermore, the base station includes a switching unit that connects at least one of the first distributed unit and the second distributed unit and the control unit. When the user equipment is connected to the first radio unit and the control unit selects the second distributed unit, the first distributed unit controls the switching unit so that the data received from the first radio unit can be transmitted to the second distributed unit.

[0009] The connection method according to the third aspect is a connection method in a base station having a first radio unit and a second radio unit capable of wireless communication with a user device, a first distributed unit including a first scheduler for a first service, a second distributed unit including a second scheduler for a second service different from the first service, a control unit for controlling the first distributed unit and the second distributed unit, and a switching unit. The connection method includes a step of connecting, by the switching unit, any one of the first radio unit and the second radio unit that is to be wirelessly connected to the user device and the distributed unit selected by the control unit among the first distributed unit and the second distributed unit.

[0010] The connection method according to the fourth aspect is a connection method in a base station having a first radio unit and a second radio unit capable of wireless communication with a user device, a first distributed unit including a first scheduler for a first service, a second distributed unit including a second scheduler for a second service different from the first service, a control unit for controlling the first distributed unit and the second distributed unit, and a switching unit for connecting either the first distributed unit or the second distributed unit to the control unit. The connection method includes a step of controlling, by the first distributed unit, the switching unit so that data received from the first radio unit can be transmitted to the second distributed unit when the user device is connected to the first radio unit and the control unit selects the second distributed unit.

Advantages of the Invention

[0011] According to one aspect, an appropriate service can be provided to the user device without changing the wireless connection with the user device.

Brief Description of the Drawings

[0012]

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DETAILED DESCRIPTION OF THE INVENTION

[0013] [First Embodiment] As described above, in the 5G system, QoS services can be provided by QoS flows. Also, it is possible to set a plurality of QoS flows in one gNB-DU in the gNB.

[0014] However, when different types of QoS flows are set in one gNB-DU, the performance of the entire 5G system may deteriorate.

[0015] For example, QoS flows are classified into three types: GBR (Guaranteed Bit Rate), Non-GBR, and Delay Critical GBR. Among these, Delay Critical GBR has the most stringent operating conditions compared to other types. When a Delay Critical GBR QoS flow and other QoS flows are set in a single gNB-DU, if the Delay Critical GBR QoS flow is prioritized, although operation guarantee for this QoS flow becomes possible, other QoS flows will be affected, and throughput in the gNB-DU may decrease. Also, for Delay Critical GBR, the scheduling process tends to be complicated, and there may be a situation where the throughput of the entire 5G system decreases.

[0016] Also, for example, when a QoS flow for URLLC and QoS flows other than URLLC are set in a single gNB-DU, if the QoS flow for URLLC is prioritized, in the gNB-DU, the throughput of QoS flows other than URLLC may be affected and decrease.

[0017] The influence of such QoS flows affects not only the gNB-DU but also the entire gNB and even the entire 5G system in some cases.

[0018] Therefore, in this embodiment, schedulers for different services are set for each gNB-DU. And in this embodiment, when a QoS flow is established, the gNB-CU selects one of the gNB-DUs for the QoS flow.

[0019] As a result, for example, for an established QoS flow, it becomes possible to perform processing in one of the distributed units (gNB-DUs). Therefore, the influence on other distributed units can be suppressed, and the performance degradation in the gNB200 can be suppressed.

[0020] However, the selected distributed unit (gNB-DU) and the radio unit (gNB-RU (Radio Unit)) to which the user equipment makes a wireless connection may belong to different RANs.

[0021] In such a case, it is also conceivable that the base station causes the user equipment to perform handover to the radio unit to which the selected distributed unit belongs.

[0022] However, causing the user equipment to perform handover will cause a load on the user equipment because it will cause the base station and the user equipment to execute a predetermined procedure regarding handover. On the other hand, the base station wants to be able to provide an appropriate service to the user equipment.

[0023] Therefore, the present embodiment aims to provide an appropriate service to the user equipment without changing the wireless connection with the user equipment.

[0024] Hereinafter, the embodiments will be specifically 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.

[0025] (Configuration example of a mobile communication system) FIG. 1 is a diagram showing a configuration example of a mobile communication system 10 according to an embodiment.

[0026] As shown in FIG. 1, the mobile communication system 10 includes a UE 100, a gNB 200, and a CN (Core Network) 300.

[0027] UE (or user equipment. Hereinafter, it may be referred to as "UE") 100 is a wireless communication device capable of wireless communication with gNB 200. UE 100 may be any device as long as it is capable of wireless communication with gNB 200. For example, a smartphone, a feature phone, a tablet terminal, an IoT (Internet of Things) device, a personal computer, a sensor or a device provided in a sensor, a vehicle or a device provided in a vehicle, an aircraft or a device provided in an aircraft, etc. In the example of FIG. 1, an example of one UE 100 is shown, but there may be a plurality of UEs.

[0028] gNB 200 is an example of a base station. gNB 200 is a wireless communication device capable of wireless connection with UE 100. Also, gNB 200 is a communication device capable of communicating with a node connected to CN 300. gNB 200 functions as a base station in a 5G system. gNB 200 performs wireless communication with a UE (or user equipment) 100 and provides various services to UE 100. Instead of gNB, en-gNB or the like may be used.

[0029] Note that the network between UE 100 and gNB 200 may be called NG-RAN (Next Generation-Radio Access Network) or RAN in a 5G system.

[0030] CN 300 is a network between gNB 200 and a functional unit (or functional entity) within CN 300. Examples of functional units within CN 300 include SMF, AMF (Access and Mobility Management Function), and UPF. The establishment or update of a PDU session, etc. is performed by the functional units within CN 300. Also, the functional units can transmit user data to UE 100 via gNB 200 or transmit user data transmitted from UE 100 to other networks.

[0031] (Configuration Example of gNB) Next, a configuration example of the gNB 200 will be described.

[0032] FIG. 1 is a diagram showing a configuration example of the gNB 200 according to an embodiment.

[0033] As shown in FIG. 1, the gNB 200 includes a CU 250, a plurality of DUs 212, 222, 232, a switching unit (or SW. Hereinafter, it may be referred to as "SW"), 260, and a plurality of RUs (Radio Units) 211, 221, 231.

[0034] The CU 250 may be referred to as an aggregation unit, for example. The CU 250 is connected to each of the DUs 212, 222, 232 to control each of the DUs 212, 222, 232. Further, the CU 250 can select any one of the plurality of DUs 212, 222, 232 to communicate with the UE 100. The CU 250 is connected to the CN 300 and performs transmission and reception of user data and the like with the CN 300. The CU 250 selects any one of the plurality of DUs 212, 222, 232 by DU selection for an established QoS flow. Thereby, the CU 250 can cause any one of the schedulers 213, 223, 233 to perform scheduling processing for the QoS flow.

[0035] Each of the DUs 212, 222, 232 may be referred to as a distributed unit, for example. DU #1 (212) is connected to the CU 250 and also connected to the SW 260. Also, DU #2 (222) is connected to the CU 250 and connected to the SW 260. Further, DU #3 (232) is connected to the CU 250 and connected to the SW 260.

[0036] Each of the DUs 212, 222, and 232 has a scheduler 213, 223, and 233 respectively. That is, DU #1 (212) includes scheduler #1 (213), DU #2 (222) includes scheduler #2 (223), and DU #3 (232) includes scheduler #3 (233). When each scheduler 213, 223, 233 performs wireless communication with the UE 100, scheduling processes such as allocating wireless resources to the UE 100 are performed.

[0037] In one embodiment, each of the schedulers 213, 223, 233 is a scheduler for a different service.

[0038] First, as the service, it may be any of eMBB, URLLC, and mMTC. For example, scheduler #1 (213) is a scheduler for eMBB, scheduler #2 (223) is a scheduler for URLLC, and scheduler #3 (233) is a scheduler for mMTC. For example, scheduler #1 (213) may be the first scheduler for the first service, or scheduler #2 (223) may be the second scheduler for the second service different from the first service.

[0039] In the scheduler for eMBB, for example, scheduling may be performed to allocate a large amount of wireless resources to the UE 100 with good wireless conditions. Also, in the scheduler for URLLC, a wireless resource area that can be interrupted for URLLC may be reserved in advance, and scheduling may be performed to allocate the wireless resources to the UE 100. Further, in the scheduler for mMTC, considering the possibility of simultaneous wireless communication from a large number of UEs 100, a wireless resource area may be reserved in advance, and scheduling may be performed to allocate the wireless resources to the UE 100.

[0040] Second, as a service, it may be any of GBR, Non-GBR, and Delay Critical GBR. For example, scheduler #1 (213) is a scheduler for GBR, scheduler #2 (223) is a scheduler for Non-GBR, and scheduler #3 (233) is a scheduler for Delay Critical GBR. In each of the schedulers 213, 223, 233, radio resource regions may be reserved in advance so that QoS characteristics corresponding to the type of QoS flow (or resource type) can be obtained, and scheduling may be performed to allocate the radio resources to the UE 100.

[0041] However, for one service, multiple schedulers may be set as the scheduler for that service. For example, scheduler #1 (213) and scheduler #2 (223) may be set as the scheduler for URLLC. Also, for example, scheduler #1 (213) and scheduler #2 (223) may be set as the scheduler for Delay Critical GBR. These services are more likely to affect other services compared to others, and with multiple schedulers, it becomes possible to allocate more radio resources to the UE 100.

[0042] Each of the RUs 211, 221, 231 may be referred to as a radio unit, for example. RU #1 (211) (e.g., the first radio unit) is connected to the SW 260. Also, RU #1 (211) is controlled by DU #1 (212) and can perform wireless communication with the UE 100. Also, RU #2 (221) (e.g., the second radio unit) is connected to the SW 260. RU #2 (221) is controlled by DU #2 (222) and can perform wireless communication with the UE 100. Further, RU #3 (231) is connected to the SW 260. RU #3 (231) is controlled by DU #3 (232) and can perform wireless communication with the UE 100.

[0043] SW260 connects at least one of the plurality of RUs 211, 221, 231 to at least one of the plurality of DUs 212, 222, 232. Specifically, SW260 connects any one of the plurality of RUs that is wirelessly connected to UE100 to any one of the plurality of DUs selected by CU250 through DU selection. In particular, when the RU (e.g., RU#1 (211)) wirelessly connected by UE100 and the DU (e.g., DU#2 (222)) selected by CU250 belong to different RANs (Radio Access Networks), the RU and the DU are connected. In this case, when the DU (e.g., DU#1 (212)) belonging to the same RAN as the RU (e.g., RU#1 (211)) is connected to the RU, SW260 switches the connection from the DU (e.g., DU#1 (212)) belonging to the same RAN to the DU (e.g., DU#2 (222)) selected by CU250.

[0044] Here, the RAN is the network part in the mobile communication system 10 that provides wireless communication to UE100. Also, the RAN may be a set of network parts that provide the same function regarding wireless communication. For example, one RAN may be constituted by RU#1 (211) and DU#1 (212), one RAN may be constituted by RU#2 (221) and DU#2 (222), and one RAN may be constituted by RU#3 (231) and DU#3 (232). Thus, a plurality of RANs (three RANs in the example of FIG. 1) may be constituted in one gNB200, or one RAN may be constituted in one gNB200.

[0045] Note that hereinafter, DU#1 (212) may be used as a representative for description among the plurality of DUs 212, 222, 232. Also, RU#1 (211) may be used as a representative for description among the plurality of RUs 211, 221, 231. Furthermore, scheduler#1 (213) may be used as a representative for description among the plurality of schedulers 213, 223, 233.

[0046] (Configuration examples of CU, DU, and RU) Figure 2(A) is a diagram showing a configuration example of CU250 according to an embodiment.

[0047] As shown in Figure 2(A), CU250 has an interface unit 251 and a control unit 252.

[0048] The interface unit 251 transmits and receives messages, etc. to and from CN300 under the control of the control unit 252, and also transmits and receives messages to and from any one of the plurality of DUs 212, 222, 232. For example, the interface unit 251 transmits and receives NG interface messages to and from CN300, and transmits and receives F1 interface messages to and from each of the DUs 212, 222, 232.

[0049] The control unit 252 performs various controls in CU250. The control unit 252 selects any one of the plurality of DUs 212, 222, 232 for an established QoS flow. That is, the control unit 252 performs DU selection. Also, the control unit 252 may control the connection (or switching) of SW260. Therefore, the control unit 252 may control the connection by transmitting a connection control signal to SW260.

[0050] Note that the control unit 120 has at least one memory and at least one processor electrically connected to the memory. The memory includes a volatile memory and a non-volatile memory, and stores information used in the processing by the processor and a program executed by the processor. The processor may perform various processes by executing the program stored in the memory.

[0051] Figure 2(B) is a diagram showing a configuration example of DU#1 (212) according to an embodiment. Other DUs #2 (222) and #3 (232) have the same configuration as DU#1 (212).

[0052] As shown in FIG. 2(B), DU#1 (212) has an interface unit 2120 and a control unit 2121.

[0053] The interface unit 2120 transmits and receives messages and the like to and from CU250 under the control of the control unit 2121, and transmits and receives messages to and from SW260. For example, the interface unit 2120 transmits and receives F1 interface messages to and from CU250, and transmits and receives O-RAN (Open Radio Access Network) fronthaul specification messages to and from SW260.

[0054] The control unit 2121 performs various controls in DU#1 (212). The control unit 2121 may control the connection in SW260. Therefore, the control unit 2121 may control the connection by outputting a connection control signal to SW260. The control unit 2121 includes a scheduler#1 (213). As described above, the scheduler#1 (213) has a scheduling function for supporting a predetermined service.

[0055] Note that the control unit 2121 has at least one memory and at least one processor electrically connected to the memory. The memory includes a volatile memory and a non-volatile memory, and stores information used in the processing in the processor and a program executed by the processor. The processor may perform various processes by executing the program stored in the memory.

[0056] FIG. 3 is a diagram showing a configuration example of RU#1 (211) according to an embodiment. RU#2 (221) and RU#3 (231) also have the same configuration as RU#1 (211).

[0057] As shown in FIG. 3, RU#1 (211) has an interface unit 2110, a radio processing unit 2111, and an antenna 2112.

[0058] The interface unit 2110 transmits and receives messages to and from SW260, and transmits and receives data and the like to and from the wireless processing unit 2111. That is, the interface unit 2110 receives a message transmitted from SW260, extracts data, a control signal, or the like from the message, and outputs the extracted data, control signal, or the like to the wireless processing unit 2111. Further, the interface unit 2110 generates a message in a predetermined format including these for the data, control signal, or the like output from the wireless processing unit 2111, and transmits the message to SW260. For example, the interface unit 2210 transmits and receives messages in accordance with the O-RAN fronthaul specification to and from SW260.

[0059] The wireless processing unit 2111 converts (up-converts) data, a control signal, or the like output from the interface unit 2110 into a wireless signal in a wireless band, and outputs the wireless signal to the antenna 2112. Further, the wireless processing unit 2111 converts (down-converts) the wireless signal output from the antenna 2112 into data, a wireless signal, or the like in a baseband band, and outputs the data, wireless signal, or the like to the interface unit 2110.

[0060] The antenna 2112 transmits the wireless signal output from the wireless processing unit 2111 to the UE100. Further, the antenna 2112 receives the wireless signal transmitted from the UE100, and outputs the received wireless signal to the wireless processing unit 2111. The antenna 2112 uses the wireless resources allocated by the scheduler included in the DU selected by DU selection among the schedulers 213, 223, 223 to receive and transmit wireless signals.

[0061] (QoS flow) Here, the QoS flow will be described.

[0062] A QoS flow is the finest granularity for differentiating QoS in a PDU session. The QoS flow is controlled by the SMF of the CN300. Also, the QoS flow is established in the PDU Session Establishment procedure or the PDU Session Modification procedure. The QoS flow may be pre-configured.

[0063] In a 5G system, a QoS Flow ID (QFI) is used to identify a QoS flow. Also, a 5G QoS Identifier (5QI) is used to identify each QoS.

[0064] Each QoS flow is associated with QoS parameters and QoS characteristics. The QoS parameters include the 5QI and the ARP (Allocation and Retention Priority) including information such as priority. Also, the QoS characteristics include the resource type, the priority level, the packet error rate, and the maximum value of the allowable delay time (Packet Delay Budget) between the UE100 and the UPF. Such QoS parameters and QoS characteristics can characterize the QoS flow.

[0065] The QoS profile is defined as including QoS parameters. The QoS profile, together with the QFI, is sent from the SMF to the RAN via the AMF. Specifically, the QoS profile and the QFI are sent to the RAN using the N2 interface during the PDU session establishment procedure or the PDU session modification procedure. The QoS characteristics are also sent to the RAN as part of the QoS profile. A PDU session including one or more QoS flows is established between the UE100 and the UPF by the PDU session establishment procedure or the PDU session modification procedure.

[0066] In gNB200 (or RAN), each QoS flow is mapped to RAN resources (i.e., data bearers) based on the QoS profile and QFI. At this time, as described above, the CU250 of gNB200 selects one of the plurality of DUs 212, 222, 232 by CU selection, and causes the selected DU to perform the processing for the established QoS flow.

[0067] (Operation Example) Next, an operation example will be described.

[0068] For example, consider the following case. That is, as shown in FIG. 1, it is assumed that the UE100 is wirelessly connected to the RU#1 (211) of the gNB200. Also, it is assumed that the CU250 selects the DU#2 (222) by DU selection. In such a case, the SW260 connects the RU#1 (211) and the DU#2 (222).

[0069] Specifically, the SW260 connects any one of the radio units (e.g., RU#1 (211)) wirelessly connected to the user device (e.g., UE100) among the first radio unit (e.g., RU#1 (211)) and the second radio unit (e.g., RU#2 (221)), and the distributed unit (e.g., DU#2 (222)) selected by the control unit (e.g., SU250) among the first distributed unit (e.g., DU#1 (212)) and the second distributed unit (e.g., DU#2 (222)).

[0070] Thereby, for example, in the gNB200, it is possible to provide an appropriate service to the UE100 via the DU#2 (222) that supports the service to the UE100 without changing the wireless connection with the UE100.

[0071] The entity that controls the connection (or switching) of SW260 may be DU#2 (222) selected by DU selection. Specifically, when the user equipment is connected to the first radio unit (for example, RU#1 (211)) and the control unit (for example, CU250) selects the second distributed unit (for example, DU#2 (222)), the second distributed unit controls the switching unit (for example, SW260) to connect the second distributed unit and the first radio unit.

[0072] Thereby, for example, DU#2 (222) can transmit downlink data to RU#1 (211) via SW260. Therefore, gNB200 can provide appropriate services to UE100 without changing the radio connection.

[0073] Also, the entity that controls the connection (or switching) of SW260 may be RU#1 (211) wirelessly connected to UE100. Specifically, when the user equipment (for example, UE100) is connected to the first radio unit and the control unit (for example, CU250) selects the second distributed unit (for example, DU#2 (222)), the first radio unit controls the switching unit (for example, SW260) to connect the first radio unit and the second distributed unit.

[0074] Thereby, for example, RU#1 (211) can transmit uplink data to DU#2 (222) via SW260. Therefore, gNB200 can provide appropriate services to UE100 via DU#2 (222) without changing the radio connection.

[0075] Furthermore, the entity that controls the connection (or switching) of SW260 may be CU250. Specifically, the control unit (for example, CU250) controls the connection (or switching) of the switching unit (for example, SW260).

[0076] Furthermore, the entity that controls the connection (or switching) of SW260 may be DU#1 (212). Specifically, when the user device (e.g., UE100) is connected to the first radio unit (e.g., RU#1 (211)) and the control unit (e.g., CU250) selects the second distributed unit (e.g., DU#2 (222)), the first distributed unit (e.g., DU#1 (212)) controls the switching unit (e.g., SW260) to transmit the data received from the first radio unit to the second distributed unit via the switching unit.

[0077] Thereby, for example, gNB200 can provide an appropriate service to UE100 via DU#2 (222) without changing the radio connection. Also, since the service for UE100 can be provided by two DUs, DU#1 (212) and DU#2 (222), it is possible to achieve load sharing among the DUs. In this case, DU#1 (212) can also switch to DU#2 (222) via SW260 considering its own load.

[0078] In the following operation example, first, DU selection will be described. Next, the connection (or switching) operation by SW260 will be described.

[0079] (DU Selection) Figure 4 is a diagram showing an operation example of DU selection. Figure 4 shows an operation example when DU selection is performed when UE100 establishes a PDU session.

[0080] Assume that UE100 is connected to RU#1(211). Also, assume that the scheduler #1(213) of DU#1(212) is an eMBB-oriented scheduler, the scheduler #2(223) of DU#2(222) is a URLLC-oriented scheduler, and the scheduler #3(233) of DU#3(232) is an mMTC-oriented scheduler. Furthermore, assume that RAN#1 is constituted by RU#1(211) and DU#1(212), RAN#2 is constituted by RU#2(221) and DU#2(222), and RAN#3 is constituted by RU#3(231) and DU#3(232).

[0081] As shown in FIG. 4, in step S10, UE100 starts an application related to URLLC.

[0082] Steps S11 to S14 are procedures performed when UE100 establishes a PDU session. That is, UE100 sends a PDU Session Establishment request to CN300 via RAN#1 and CU250 (step S11), and CN300 sends an N2 PDU Session Request to CU250 (step S12).

[0083] The N2 PDU Session Request includes N2 SM information, etc. The N2 SM information includes information for establishing a QoS flow for URLLC. Specifically, it includes a QoS profile and QFI related to URLLC. Based on the N2 SM information, CU250 can grasp the type of QoS flow for UE100 (URLLC) and that a QoS flow for URLLC has been established for the UE100.

[0084] After that, the UE 100 and the CU 250 execute an AN-specific resource setup via RAN#1 (step S13), and the CU 250 transmits an N2 PDU Session Response to the CN 300 (step S14).

[0085] As described above, a PDU session including a QoS flow for URLLC is established between the UE 100 and the UPF.

[0086] In step S15, the CU 250 performs a DU selection process.

[0087] FIG. 5 is a flowchart showing an example of the DU selection process according to an embodiment.

[0088] As shown in FIG. 5, in step S150, the control unit 252 of the CU 250 starts the process.

[0089] In step S151, the control unit 252 receives N2 SM information.

[0090] In step S152, the control unit 252 selects one of the DUs 212, 222, 232 for the QoS flow established by the N2 SM information. Here, the control unit 252 selects DU#2 (222) having a scheduler #2 (223) for URLLC in order to recognize that the QoS flow for URLLC has been established for the UE 100.

[0091] In step S153, the control unit 252 ends the CU selection process.

[0092] FIG. 6 is a flowchart showing an example of the DU selection process according to an embodiment. The DU selection process in FIG. 6 may be another example of the DU selection process in FIG. 5.

[0093] Before the process of FIG. 6 starts, for example, assume that the scheduler #2 (223) of DU#2 (222) is set as a scheduler for Delay Critical GBR.

[0094] In step S150, the control unit 252 starts the process.

[0095] In step S151, similar to FIG. 5, the control unit 252 receives N2 SM information.

[0096] In step S154, the control unit 252 determines whether Delay Critical GBR is set based on the N2 SM information. If Delay Critical GBR is set (YES in step S154), the process proceeds to step S155. On the other hand, if Delay Critical GBR is not set (NO in step S154), the process proceeds to step S157. For example, the control unit 252 may determine whether Delay Critical GBR is set as a QoS flow for URLLC.

[0097] In step S155, the control unit 252 selects DU#2 (222) having the scheduler #2 (223) for Delay Critical GBR. Then, SW260 performs connection processing. Details of the connection processing will be described later.

[0098] Then, in step S156, the control unit 252 ends the series of processes.

[0099] On the other hand, in step S157, the control unit 252 performs distribution based on the number of GBR connections. Since the set QoS flow is not Delay Critical GBR, distribution of GBR is performed in consideration of the GBR connection status so that the bandwidth of one DU is not occupied. In the example of FIG. 6, in steps S158 and S159, the control unit 252 distributes each GBR to DUs #1 (212) and #3 (232) other than DU #2 (222) where Delay Critical GBR is set so that the number of GBR connections is made equal. After the distribution process, SW260 performs a connection process. Details of the connection process will be described later.

[0100] Then, in step S156, the control unit 252 ends a series of processes.

[0101] (Connection operation) Next, the connection (or switching) operation in SW260 will be described. In the following, there may be cases where "connection" and "switching" are used without distinction. For example, in the following, a case where RU #1 (211) and DU #2 (222) are connected in SW260 will be described. Before such a connection is made, if RU #1 (211) and DU #1 (212) are connected, then by "switching", RU #1 (211) and DU #2 (222) will be "connected". For this reason, the operation of "switching" may be included in "connection", and thus there may be cases where "connection" and "switching" are used without distinction.

[0102] FIG. 7 is a flowchart showing an example of the connection operation. The process shown in FIG. 7 may be performed, for example, at the timing of step S155, step S158, or step S159 in FIG. 6. The process shown in FIG. 7 is performed after DU selection by CU250.

[0103] Note that, as in the case described above, it is assumed that UE100 is connected to RU #1 (211). Also, it is assumed that CU250 has selected DU #2 (222) by DU selection.

[0104] In step S160, SW260 starts the process.

[0105] In step S161, SW260 connects RU and DU. For example, SW260 connects RU#1(211) and DU#2(222). When RU#1(211) and DU#1(212) are connected, SW260 switches the connection from DU#1(212) to DU#2(222).

[0106] As described above, the entity for connection control in SW260 may be DU#2(222). In this case, for example, DU#2(222) outputs a connection control signal to SW260, and in SW260, connection control between DU#2(222) and RU#1(211) is performed. Thereby, DU#2(222) can transmit downstream data to RU#1(211).

[0107] Also, as described above, the entity for connection control in SW260 may be RU#1(211). In this case, for example, RU#1(211) outputs a connection control signal to SW260, and in SW260, connection control between, for example, DU#2(222) and RU#1(211) is performed. Thereby, RU#1(211) can transmit upstream data to DU#2(222).

[0108] Furthermore, as described above, the entity for connection control of SW260 may be DU#1(212). In this case, DU#1(212) receives upstream data from RU#1(211) via SW260. Then, DU#1(212) outputs a connection switching signal to SW260, and in SW260, connection control between DU#1(212) and DU#2(222) is performed. Thereby, DU#1(212) can transmit the upstream data to DU#2(222) selected by DU selection.

[0109] Furthermore, as described above, the entity for connection control of SW260 may be CU250. CU250 grasps RU#1 (211) to which UE100 is connected. Also, CU250 grasps DU#1 (212) selected in DU selection. Therefore, CU250 can grasp what kind of connection should be made in SW260 and can perform appropriate connection control on SW260.

[0110] And in step S162, SW260 ends a series of processes.

[0111] (Modification Example 1) Next, Modification Example 1 will be described.

[0112] Modification Example 1 is an example where the timing at which DU selection is performed is different from the above-described operation example.

[0113] FIG. 8 is a diagram showing an operation example of Modification Example 1. In Modification Example 1, mainly the parts different from the first embodiment will be described, and the description of the other parts will be omitted as being the same as those of the first embodiment.

[0114] The example of FIG. 8 shows an operation example where DU selection is performed triggered by the case where UE100 ends the URLLC service. Basically, it is the same as the case of the first embodiment (when starting the URLLC service).

[0115] That is, in step S30, UE100 ends the application for the URLLC service.

[0116] After that, in steps S31 to S34, a PDU session modification procedure is executed. That is, the UE 100 transmits a PDU Session Modification request to the CN 300 via the RAN #2 (220) and the CU 250 (step S31). The CN 300 transmits an N2 Session Request to the CU 250 (step S32). The N2 Session Request includes N2 SM information and the like. The N2 SM information includes information for updating the QoS flow for URLLC. By receiving the N2 Session Request, the CU 250 can recognize that the QoS flow for URLLC has been updated. The CU 250 executes an AN-specific resource setup (step S33) and transmits an N2 Session Response to the CN 300 (step S34).

[0117] After that, in step S35, the CU 250 performs a DU selection process. Further, in the gNB 200, connection control in the SW 260 is performed after the DU selection.

[0118] In this way, the DU selection may be performed when the UE 100 starts (or selects) a service (for example, in the first embodiment), when the UE 100 terminates the service (modification example 1), and further when the UE 100 makes an initial connection with the gNB 200.

[0119] (Modification example 2) Next, modification example 2 will be described. Regarding modification example 2, mainly the parts different from the first embodiment will be described, and the description of the other parts will be omitted assuming they are the same as those in the first embodiment.

[0120] In the first embodiment, an example where the SW 260 is provided between the RU and the DU has been described (for example, FIG. 1). In modification example 2, an example where the SW 260 is provided between the DU and the CU 250 will be described.

[0121] FIG. 9 is a diagram showing a configuration example of the mobile communication system 10 according to Modification 2.

[0122] As shown in FIG. 9, SW260 is provided between the DU and the CU250.

[0123] Specifically, the switching unit (for example, SW260) connects at least one of the first distributed unit (for example, DU#1(212)) and the second distributed unit (for example, DU#2(222)) to the control unit (for example, CU250). When the user device is connected to the first radio unit (for example, RU#1(211)) and the control unit selects the second distributed unit, the first distributed unit controls the switching unit so that the data received from the first radio unit is transmitted to the second distributed unit.

[0124] Thereby, for example, DU#1(212) can transmit the uplink data to DU#2(222) via SW260. Therefore, the scheduler #2(223) of DU#2(222) that supports the service of UE100 can provide an appropriate service to UE100 without changing the radio connection.

[0125] [Other Embodiments] In the above-described operation example, the URLLC service has been described as an example of the service supported by UE100. For example, even when UE100 is an eMBB service or an mMTC service as a service other than URLLC, it can be similarly implemented. In this case, for example, when a QoS flow for the eMBB service is established, CU250 may select DU#1(212) having a scheduler #1(213) for eMBB. Further, for example, when a QoS flow for the mMTC service is established, CU250 may select DU#3(232) having a scheduler #3(233) for mMTC. Then, it may be controlled to connect the selected DU#1(212) (or DU#3(232)) and RU#1(211) to which UE100 is wirelessly connected at SW260.

[0126] Also, in the above-described operation example, for example, even when UE100 selects any one of GBR, Non-GBR, and Delay Critical GBR (and when any one of GBR, Non-GBR, and Delay Critical GBR ends), it can be similarly implemented. In this case, for example, when a QoS flow for Non-GBR is established, the control unit 252 may select DU#3 (232) having a scheduler #3 (233) for Non-GBR by DU selection processing. Then, it may be controlled to connect the selected DU#3 (232) and the RU#1 (211) to which UE100 is wirelessly connected at SW260.

[0127] Furthermore, in the above-described operation example, an example where UE100 is wirelessly connected to RU#1 (211) has been described. UE100 may be wirelessly connected to RU#2 (221) or RU#3 (231). In this case, SW260 may connect RU#2 (221) (or RU#3 (231)) wirelessly connected to UE100 and DU#2 (222). Furthermore, the CU250 may select a DU other than DU#2 (222) (for example, DU#1 (212) or DU#3 (232)). Also in this case, SW260 may connect RU#1 (211) wirelessly connected to UE100 and DU#1 (212) (or DU#3 (232)) selected by CU250.

[0128] A program for causing a computer to execute each process according to the above-described embodiment may be provided. The program may be recorded on a computer-readable medium. By using a computer-readable medium, it is possible to install the program 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. Such a recording medium may be included in the control unit 252 of the CU250 and the control unit 2121 of the DU#1(212). The control unit 252 of the CU250 and the control unit 2121 of the DU#1(212) may read the program from the recording medium and execute it to realize the functions described in the above-described embodiment. Therefore, the control unit 252 and the control unit 2121 may be a processor or a controller such as a CPU (Central Processing Unit) or a DSP (Digital Signal Processor).

[0129] As described above, the embodiments have been described in detail with reference to the drawings, but the specific configuration is not limited to the above, and various design changes and the like can be made without departing from the gist. Also, within a non-contradictory range, it is possible to combine each embodiment, each operation example, or each process.

Description of Reference Numerals

[0130] 10: Mobile communication system 100: UE 200: Base station (gNB) 210: RAN#1 211: RU#1 212: DU#1 213: Scheduler#1 221: RU#2 222: DU#2 223: Scheduler#2 231: RU#3 232: DU#3 233: Scheduler#3 250: CU 252: Control unit 260: SW 300: CN

Claims

1. In a base station capable of wireless communication with a user device, a first radio unit and a second radio unit capable of wireless communication with the user device; a first distributed unit including a first scheduler for a first service; a second distributed unit including a second scheduler for a second service different from the first service; a control unit for controlling the first distributed unit and the second distributed unit; a switching unit for connecting any one of the first radio unit and the second radio unit that is wirelessly connected to the user device among the first radio unit and the second radio unit, and the distributed unit selected by the control unit among the first distributed unit and the second distributed unit; The control unit controls the switching unit so that the first service or the second service can be provided without changing the wireless connection between the user device and any one of the wireless units wirelessly connected to the user device. Base station.

2. When the user device is connected to the first radio unit and the control unit selects the second distributed unit, the switching unit connects the first radio unit and the second distributed unit. The base station according to Claim 1.

3. The first distributed unit and the second distributed unit control the connection of the switching unit. The base station according to Claim 1.

4. When the user device is connected to the first radio unit and the control unit selects the second distributed unit, the second distributed unit controls the switching unit to connect the second distributed unit and the first radio unit. The base station according to Claim 3.

5. The first radio unit and the second radio unit control the connection of the switching unit. The base station according to Claim 1.

6. When the user device is connected to the first radio unit and the control unit selects the second distributed unit, the first radio unit controls the switching unit to connect the first radio unit and the second distributed unit. The base station according to Claim 5.

7. When the user device is connected to the first radio unit and the control unit selects the second distributed unit, the first distributed unit controls the switching unit to transmit the data received from the first radio unit via the switching unit to the second distributed unit. The base station according to Claim 1.

8. The control unit controls the connection of the switching unit. The base station according to claim 1.

9. In a base station capable of wireless communication with a user device, a first radio unit and a second radio unit capable of wireless communication with the user device; a first distributed unit including a first scheduler for a first service; a second distributed unit including a second scheduler for a second service different from the first service; a control unit for controlling the first distributed unit and the second distributed unit; a switching unit for connecting at least one of the first distributed unit and the second distributed unit to the control unit, and having when the user device is connected to the first radio unit and the control unit selects the second distributed unit, the first distributed unit controls the switching unit so as to be able to transmit data received from the first radio unit to the second distributed unit; Base station.

10. A first radio unit and a second radio unit capable of wireless communication with a user device; a first distributed unit including a first scheduler for a first service; a second distributed unit including a second scheduler for a second service different from the first service; a control unit for controlling the first distributed unit and the second distributed unit; A connection method in a base station having a switching unit, comprising: a step of connecting, by the switching unit, any one of the first radio unit and the second radio unit wirelessly connected to the user device and the distributed unit selected by the control unit among the first distributed unit and the second distributed unit; The control unit controls the switching unit so that the first service or the second service can be provided without changing the wireless connection between the user device and any one of the radio units wirelessly connected to the user device. Connection method.

11. A first radio unit and a second radio unit capable of wireless communication with a user device; a first distributed unit including a first scheduler for a first service; a second distributed unit including a second scheduler for a second service different from the first service; a control unit for controlling the first distributed unit and the second distributed unit; A connection method in a base station having a switching unit for connecting either the first distributed unit or the second distributed unit to the control unit, comprising: When the user device is connected to the first radio unit by the first distribution unit and the control unit selects the second distribution unit, a step of controlling the switching unit so that data received from the first radio unit can be transmitted to the second distribution unit. Connection method.

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