Base station function allocation control device, base station function allocation control method, and computer program

Abstract

To properly control execution of a base station function arrangement in a wireless access network of an O-RAN specification.SOLUTION: The present invention includes: a cell group information storage unit for storing cell group information showing a cell group to which a plurality of cells in a wireless access network of an O-RAN specification belong; and a control unit for making an arrangement change timing to change a base station function arrangement for each cell of one cell group, different according to each cell.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a base station function allocation control device, a base station function allocation control method, and a computer program. [Background technology]

[0002] In the fifth generation (5G) mobile communication system (hereinafter referred to as the 5G system), studies are being conducted to further improve performance from the initial system in terms of, for example, throughput, communication delay, number of connections, etc. In addition, a wide variety of services, such as robot control, connected cars, AR (Augmented Reality), and VR (Virtual Reality), are beginning to be provided using the 5G system, and it is becoming increasingly important to satisfy the communication quality required by each individual service.

[0003] Radio Access Network (RAN) slicing technology is known as a wireless communication technology for satisfying the communication quality required by such diversifying services. RAN slicing technology is a technology that divides the RAN into multiple logical networks (slices) and flexibly customizes the slices according to the services (for example, see Patent Document 1).

[0004] According to the RAN slicing technology, for example, by changing the arrangement of CU (Central Unit) and DU (Distributed Unit), which are base station functions, communication delay, cooperation performance between cells, and required network resources (radio resources, computer resources, and transmission path resources) change. For this reason, in the technology described in Patent Document 1, by connecting multiple sets of vCU (Virtual CU) and vDU (Virtual DU) to an RU (Radio Unit) that forms a single cell, multiple slices of different base station function arrangements are realized for a single cell.

[0005] In addition, the Open Radio Access Network (O-RAN) Alliance is considering opening up and making intelligent next-generation radio access networks such as 5G systems (see, for example, Non-Patent Document 1). Among the O-RAN specifications formulated by the O-RAN Alliance, Non-Patent Document 1 specifies a use case in which a Network Slice Subnet Instance (NSSI) is optimized using a "Non-Real Time RAN Intelligent Controller (Non-RT RIC)" in response to traffic fluctuations.

[0006] In the use case of Non-Patent Document 1, the "Non-RT RIC" collects the required KPIs (Key Performance Indicators) from each node via the O1 interface. Parameters that can be collected by the O1 interface correspond to the parameters defined in Non-Patent Document 2. For example, these parameters include "DL PRB usage", "UL PRB usage", "Average DL UE throughput", "Average UL UE throughput", and "Number of PDU Sessions requested". The "Non-RT RIC" analyzes the collected information and determines changes to resources related to NSSI. For example, it changes "VNF resources" and "slice subnet attributes" (see Non-Patent Document 3). The "Non-RT RIC" changes the settings of resources related to NSSI for each node via the O1 interface.

[0007] Additionally, methods using deep reinforcement learning are being considered for network control that takes into account a variety of parameters. Deep reinforcement learning is a machine learning method that learns optimal behavior (control) through trial and error in the environment to be controlled. Furthermore, in recent years, distributed learning (distributed reinforcement learning) in deep reinforcement learning has been attracting attention in order to improve learning efficiency. For example, in "Ape-X," a method of distributed reinforcement learning, multiple "Actors" each collect experience (learning data) through trial and error with the environment, and this is learned by the "Learner." The learning model of the "Actors" is periodically updated by the "Learner." By processing multiple "Actors" in parallel, a variety of data can be learned efficiently.

[0008] Non-Patent Document 4 describes a wireless resource allocation control technology using distributed reinforcement learning. In the wireless resource allocation control technology described in Non-Patent Document 4, each "Actor" optimally controls the wireless resource allocation of each slice, thereby satisfying the quality required by users with a small number of wireless resources. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2020-136787 A [Non-patent literature]

[0010] [Non-Patent Document 1] O-RAN WG1, “Slicing architecture”, v03.00, 3.2.3 Use Case 3: NSSI Resource Allocation Optimization [Non-Patent Document 2] 3GPP, “TS 28.552”, V17.1.0, 2020-12 [Non-Patent Document 3] 3GPP, “TS 28.541”, V15.4.0, 2019-09 [Non-Patent Document 4] Yu Abiko, et al., “Flexible Resource Block Allocation to Multiple Slices for Radio Access Network Slicing Using Deep Reinforcement Learning”, IEEE Access, vol. 8, pp. 68183-68198, Apr. 2020. Summary of the Invention [Problem to be solved by the invention]

[0011] Since traffic demands in the RAN change dynamically, the traffic flowing through each slice also changes dynamically. In addition, the bandwidth required for the transmission path and the computer resources of the antenna site and the accommodating station change depending on the traffic fluctuation. For this reason, in order to satisfy the quality required by many users with limited network resources, it is preferable to adaptively change the arrangement of base station functions in the RAN according to the traffic fluctuation.

[0012] Here, when applying distributed reinforcement learning to base station function allocation, it is conceivable that each "Actor" controls the base station function allocation (mapping of slices and base station functions) of each cell. When deciding the base station function allocation, since the transmission paths shared between cells, the computer resources of the accommodating stations, and the presence or absence of inter-cell cooperation vary depending on the base station function allocation of each cell, it is preferable to decide the base station function allocation of each cell so as to maximize the quality required by users across the entire RAN.

[0013] However, in distributed reinforcement learning, "actors" act independently and do not take into account the actions of other "actors." Therefore, if each actor simultaneously performs an action (change in base station function allocation) as in the past, it is difficult to optimize the base station function allocation across the entire RAN. For example, if base station function allocation is performed so that all cells consume a lot of transmission line bandwidth just because the transmission line bandwidth is available, the transmission line will become congested. In addition, if congestion occurs due to fluctuations in traffic demand, the congestion will continue until the next time the base station function allocation is changed. For this reason, the challenge is to appropriately control the execution of base station function allocation.

[0014] The present invention has been made in consideration of the above circumstances, and has an object to appropriately control the execution of base station function placement in a radio access network conforming to the O-RAN specifications. [Means for solving the problem]

[0015] (1) One aspect of the present invention is a wireless access network that includes a radio access network conforming to the O-RAN standard, the wireless access network including a plurality of cells, the plurality of cells being included in the radio access network, and a control unit that shifts a timing of changing a base station function arrangement for each cell belonging to the one of the cell groups. the cell group is composed of a plurality of cells sharing the same transmission path, the transmission path being a transmission path between an accommodating station and an antenna site, the required bandwidth of the transmission path differs depending on the base station function arrangement, and the control unit sequentially changes the base station function arrangement in the plurality of cells so as to avoid congestion based on an observed value of an overall bandwidth usage rate of the transmission path shared by the plurality of cells belonging to the same cell group; A base station function arrangement control device. ( 2 ) One aspect of the present invention is a base station function arrangement control device according to (1) above, wherein the cell group is composed of a plurality of cells that satisfy a predetermined radio wave influence standard. ( 3 In one aspect of the present invention, the radio wave influence criterion is that the cell interval is within a predetermined distance. 2 ) base station function arrangement control device. ( 4 ) One aspect of the present invention is the above-mentioned ( 2 ) base station function arrangement control device. ( 5) One aspect of the present invention is a method for determining a base station function allocation for each cell included in the wireless access network by distributed reinforcement learning, comprising: 4 ) is a base station function arrangement control device. ( 6 ) One aspect of the present invention is that the base station function arrangement control device is realized using a "Non-RT RIC (Non-Real Time RAN Intelligent Controller)" and is described in (1) to ( 5 ) is a base station function arrangement control device.

[0016] ( 7 One aspect of the present invention is a base station function arrangement control method in an O-RAN radio access network, the method including: a cell group information storage step in which a base station function arrangement control device stores cell group information indicating a cell group to which a plurality of cells included in the O-RAN radio access network belong; and a control step in which the base station function arrangement control device shifts an arrangement change timing for changing the base station function arrangement for each cell belonging to one of the cell groups. the cell group is composed of a plurality of cells sharing the same transmission path, the transmission path being a transmission path between an accommodating station and an antenna site, and a required bandwidth of the transmission path varies depending on the base station function arrangement, and the control step sequentially changes the base station function arrangement in the plurality of cells so as to avoid congestion based on an observed value of an overall bandwidth utilization rate of the transmission path shared by the plurality of cells belonging to the same cell group. A base station function allocation control method.

[0017] (8) One aspect of the present invention is to cause a computer of a base station function arrangement control device to execute a cell group information storage step of storing cell group information indicating a cell group to which a plurality of cells included in a radio access network conforming to the O-RAN specification belong, and a control step of shifting a timing of changing the arrangement of base station functions for each cell belonging to one of the cell groups. the cell group is composed of a plurality of cells sharing the same transmission path, the transmission path being a transmission path between an accommodating station and an antenna site, and the required bandwidth of the transmission path varies depending on the base station function arrangement, and the control step sequentially changes the base station function arrangement in the plurality of cells so as to avoid congestion based on an observed value of an overall bandwidth usage rate of the transmission path shared by the plurality of cells belonging to the same cell group. It is a computer program. Effect of the Invention

[0018] According to the present invention, it is possible to obtain an effect that the execution of base station function placement can be appropriately controlled in a radio access network conforming to the O-RAN specifications. [Brief description of the drawings]

[0019] [Figure 1] FIG. 2 is a block diagram showing an example of the configuration of a radio access network according to an embodiment. [Diagram 2] FIG. 1 is an explanatory diagram illustrating an example of a base station function arrangement in a RAN according to an embodiment. [Diagram 3] 2 is a block diagram showing an example of the configuration of a base station function arrangement control unit according to an embodiment; FIG. [Figure 4] FIG. 11 is a diagram illustrating an example of the configuration of cell group information according to an embodiment. [Diagram 5] FIG. 11 is an explanatory diagram of a timing for changing a layout according to an embodiment. [Figure 6] FIG. 4 is a block diagram showing an example of the configuration of a control unit according to an embodiment. [Figure 7] 1 is a flowchart showing an outline of a base station function arrangement control method according to an embodiment. [Figure 8] 1 is a sequence diagram showing an example of a detailed procedure of a base station function arrangement control method according to an embodiment. [Figure 9] FIG. 2 is an explanatory diagram of a first example of a cell group determination method according to an embodiment. [Figure 10] FIG. 2 is an explanatory diagram of a first example of a cell group determination method according to an embodiment. [Figure 11] FIG. 11 is an explanatory diagram of example 2 of a cell group determination method according to an embodiment. [Figure 12] FIG. 11 is an explanatory diagram of example 2 of a cell group determination method according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a block diagram showing a configuration example of a radio access network according to an embodiment. The radio access network (RAN) 1 shown in Fig. 1 is a RAN to which a RAN slicing technique is applied. In addition, the O-RAN specification is applied to the RAN 1.

[0021] FIG. 2 shows an example of the arrangement of base station functions of RAN1. In the example of FIG. 2, a total of five sets of vCU and vDU are connected to RUs forming a single cell. The first example, "O-RAN slice subnet#1", is a C-RAN (Centralized-RAN) arrangement, in which both vCU and vDU are arranged in a storage station. The C-RAN arrangement is characterized in that inter-cell cooperation is possible, but the required bandwidth of the transmission path is large. The second example, "O-RAN slice subnet#2" and the third example, "O-RAN slice subnet#3", are S-RAN (Split-RAN) arrangements, in which a vDU is arranged in an antenna site and a vCU is arranged in a storage station. The S-RAN arrangement is characterized in that inter-cell cooperation is not possible, but the required bandwidth of the transmission path is small. The fourth example, "O-RAN slice subnet#4" and the fifth example, "O-RAN slice subnet#5", are D-RAN (Distributed RAN) arrangements, in which both vCU and vDU are arranged in an antenna site. D-RAN deployment does not allow for inter-cell cooperation, but has the advantage of low communication latency.

[0022] As shown in Fig. 2, in RAN1, by connecting multiple sets of vCU and vDU to RU forming a single cell, it is possible to realize slices of base station function arrangement with multiple different characteristics for a single cell. This makes it possible for RAN1 to provide wireless communication services with multiple different characteristics in a single cell, and to adapt to various communication qualities required by a wide variety of services.

[0023] In FIG. 1, the RAN 1 includes a Service and Management Orchestration (SMO) function unit (SMO Functions) 11, a "Non-RT RIC (Non-real-time RAN Intelligent Controller)" 12 including a base station function arrangement control unit 20, and a base station function group 2. The base station function arrangement control unit 20 corresponds to a base station function arrangement control device. In this embodiment, the base station function arrangement control unit 20 is realized using the "Non-RT RIC" 12. Moreover, the SMO function unit 11 and the "Non-RT RIC" 12 are realized using an SMO framework 10. The base station function group 2 is composed of an RU, a vCU, and a vDU, as exemplified in FIG. 2.

[0024] The SMO framework 10 provides an O1 interface defined in the O-RAN specification. The “Non-RT RIC” 12 acquires KPIs (Key Performance Indicators) from the base station function group 2 via the O1 interface.

[0025] The SMO function unit 11 and the “Non-RT RIC” 12 exchange messages via an interface 100. The interface 100 is an interface with the SMO function unit 11.

[0026] 3 is a block diagram showing an example of the configuration of the base station function layout control unit 20 according to this embodiment. In FIG. 3, the base station function layout control unit 20 includes a cell group information storage unit 220, a KPI acquisition unit 203, a base station function layout setting information transmission unit 204, and a control unit 205.

[0027] The functions of each unit of the base station function allocation control unit 20 are realized by the CPU executing a computer program for realizing the function of each unit.

[0028] The cell group information storage unit 220 stores cell group information. The cell group information is information indicating a cell group to which a plurality of cells included in the RAN 1 belong.

[0029] Fig. 4 shows an example of the configuration of cell group information stored in cell group information storage unit 220. In Fig. 4, the cell group information stores identifiers (cell IDs) for identifying cells belonging to a cell group of a given group ID in association with the identifier of the cell group (group ID).

[0030] The KPI acquisition unit 203 acquires the KPI from the base station function group 2 via the O1 interface. The KPIs acquired by the KPI acquisition unit 203 from the base station function group 2 include, for example, the throughput of each service, the utilization rate of wireless resources, the utilization rate of computer resources, and the utilization rate of transmission line bandwidth.

[0031] The base station function layout setting information transmission unit 204 transmits the base station function layout setting information via the interface 100 with the SMO function unit 11. The base station function layout setting information is information indicating the contents of changes to the base station function layout for changing the base station function layout in the RAN1.

[0032] The control unit 205 determines the next base station function allocation for each cell based on the KPI acquired by the KPI acquisition unit 203. The control unit 205 shifts the timing of changing the base station function allocation (allocation change timing) for each cell belonging to a cell group included in the cell group information stored in the cell group information storage unit 220.

[0033] FIG. 5 is an explanatory diagram of the placement change timing according to this embodiment. In the example of FIG. 5, placement change timing for one cell group consisting of three cells (Cell#1, Cell#2,, Cell#3) is shown. In FIG. 5, a period (placement execution period) T for executing base station function placement is set. The control unit 205 determines the placement change timing for each cell (Cell#1, Cell#2,, Cell#3) based on the placement execution period T. Specifically, for the first cell (Cell#1), the timing of the placement execution period T is the placement change timing. For the second cell (Cell#2), the timing shifted backward by the shift width ΔT from the placement change timing of the first cell (Cell#1) is the placement change timing. For the third cell (Cell#3), the timing shifted backward by the shift width ΔT from the placement change timing of the second cell (Cell#2) is the placement change timing. In the example of Fig. 5, the shift width ΔT is "ΔT = T ÷ m, m is the total number of cells in the cell group", i.e. "ΔT = T ÷ 3". In other words, in the example of Fig. 5, the timing of the placement change of each cell is shifted evenly.

[0034] As shown in FIG. 5, by shifting the timing of relocation of each cell so that they do not overlap, a change in the network state (e.g., KPI) caused by a change in the base station function allocation for one cell can be reflected in a change in the base station function allocation for the next cell. For example, when the base station function allocation for the first cell (Cell#1) is changed, the KPI for the second cell (Cell#2) changes due to the change in the base station function allocation. Here, since the timing of the relocation of the second cell (Cell#2) is shifted backward by the shift width ΔT from the timing of the relocation of the first cell (Cell#1), the next base station function allocation for the second cell (Cell#2) is determined based on the KPI after the change. As a result, the change in the base station function allocation for the second cell (Cell#2) can be changed to reflect the change in the KPI caused by the change in the base station function allocation for the first cell (Cell#1).

[0035] Fig. 6 is a block diagram showing an example of the configuration of a control unit according to this embodiment. In Fig. 6, control unit 205 determines the base station function allocation for each cell included in RAN1 by distributed reinforcement learning. RAN1 includes a plurality of cells (Cell#1, Cell#2,..., Cell#n). Control unit 205 includes a plurality of "Actors" 301 (Actor#1, Actor#2,..., Actor#n) respectively corresponding to the plurality of cells (Cell#1, Cell#2,..., Cell#n), a "Repository" 302, and a "Learner" 303.

[0036] Each "Actor" 301 collects "Experiences" (learning data) through trial and error with the cell (environment) based on the KPIs obtained from the cell it is responsible for. "Repository" 302 stores the learning data collected by each "Actor" 301. "Learner" 303 uses the learning data stored in "Repository" 302 to learn a base station function placement learning model. The base station function placement learning model of each "Actor" 301 is periodically updated by "Learner" 303. A certain "Actor" 301 uses the base station function placement learning model to optimize the base station function placement in the cell that the "Actor" 301 is responsible for.

[0037] The control unit 205 obtains an optimal solution for the allocation of base station functions in each cell (Cell#1, Cell#2,..., Cell#n) by each "Actor" 301 (Actor#1, Actor#2,..., Actor#n). At this time, the control unit 205 determines an order (cell order) indicating from which cell the optimal solution for the allocation of base station functions is to be obtained for each cell group for the multiple cells (Cell#1, Cell#2,..., Cell#n), and obtains the optimal solution for the allocation of base station functions according to the cell order.

[0038] Next, the overall procedure of the base station function allocation control method according to this embodiment will be described with reference to Fig. 7. Fig. 7 is a flowchart showing an outline of the procedure of the base station function allocation control method according to this embodiment.

[0039] (Step S11) The base station function arrangement control unit 20 (control unit 205) determines a cell group for a plurality of cells (Cell #1, Cell #2, . . . , Cell #n) based on the cell group information in the cell group information storage unit 220.

[0040] (Step S12) The base station function arrangement control unit 20 (control unit 205) determines the order of cells for each cell group for a plurality of cells (Cell #1, Cell #2, . . . , Cell #n).

[0041] Next, base station function configuration is performed for each cell (Cell#1, Cell#2,..., Cell#n) in the order of cells in each cell group determined in step S12. For example, base station function configuration may be performed for cells in the same cell group in the order of cells in the cell group, one cell group at a time. For example, base station function configuration may be performed for cells in the same cell order in each cell group in the order of cells. For convenience, the order of cells is shown in FIG. 5 as Cell#1, Cell#2,..., Cell#n.

[0042] In the execution of base station function configuration for the cell, steps S13 and S14 are executed. Here, the execution of base station function configuration will be explained using "Cell #1" as an example, but the same applies to other cells.

[0043] (Step S13) The base station function arrangement control unit 20 (KPI acquisition unit 203) acquires the KPI from "Cell #1".

[0044] (Step S14) The base station function layout control unit 20 (control unit 205) determines the next base station function layout in "Cell #1" based on the KPI acquired from "Cell #1". The base station function layout control unit 20 (control unit 205) generates base station function layout setting information related to the determined next base station function layout in "Cell #1". The base station function layout setting information is information indicating the changes to be made to the base station function layout for changing the base station function layout in "Cell #1" to the next base station function layout.

[0045] Next, the base station function layout control unit 20 (base station function layout setting information transmission unit 204) transmits the base station function layout setting information for "Cell #1" generated by the control unit 205 to the SMO function unit 11. Next, the SMO function unit 11 executes settings to change the base station function layout of "Cell #1" in the base station function group 2 based on the base station function layout setting information for "Cell #1". As a result, the base station function layout of "Cell #1" in the base station function group 2 is changed to the next base station function layout.

[0046] Next, a detailed procedure of the base station function allocation control method according to this embodiment will be described with reference to Fig. 8. Fig. 8 is a sequence diagram showing an example of a detailed procedure of the base station function allocation control method according to this embodiment.

[0047] (Step S201) The base station function deployment control unit 20 determines the execution order of base station function deployment (cell order) for each cell group.

[0048] (Step S202) Next, the base station function arrangement control unit 20 receives a “Performance measurements” message from each node (O-CU, O-DU1, O-DUN) of the base station function group 2 via the O1 interface. The base station function arrangement control unit 20 acquires the KPI from the “Performance measurements” message.

[0049] (Step S203) Next, the base station function layout control unit 20 determines the next base station function layout for each cell according to the order of the cells determined in step S201, based on the KPI acquired from the "Performance measurements" message. The base station function layout control unit 20 generates base station function layout setting information related to the next base station function layout for each determined cell.

[0050] Next, steps S204 to S205 are executed as a base station function setting change sequence. This base station function setting change sequence is based on the O-RAN specification "Reconfiguration of O-RAN Virtual Network Function(s) (O-RAN.WG6.ORCH-USE-CASES-v01.00)".

[0051] Steps S204 and S205 are executed for each cell group in the order of the cells. Here, after steps S204 and S205 are executed for one cell in the same cell group, the process returns to step S202, the next base station function arrangement is determined for the next cell in the order of the cell, and steps S204 and S205 are executed for the next cell. In this way, the process of steps S202-S205 is repeated for each cell in the same cell group in the order of the cells.

[0052] (Step S204) The base station function layout control unit 20 transmits a “Reconfig NF set” message including the base station function layout setting information generated in step S203 to the SMO function unit 11 via the interface 100. The SMO function unit 11 acquires the base station function layout setting information from the “Reconfig NF set” message received via the interface 100.

[0053] (Step S205) The SMO function unit 11 transmits a "Configure NF" message to each node (O-CU, O-DU1, O-DUN) of the base station function group 2 via the O1 interface. This "Configure NF" message includes setting information for changing to the next base station function configuration indicated in the base station function configuration setting information acquired in step S204. As a result, the base station function configuration of the cell of the base station function group 2 is changed to the next base station function configuration of the cell.

[0054] Next, a cell group determination method according to this embodiment will be described.

[0055] (Example 1 of cell group determination method) 9 is an explanatory diagram of a cell group determination method example 1 according to the present embodiment. In the cell group determination method example 1, a cell group is composed of a plurality of cells sharing the same transmission path. The shared transmission path is, for example, a transmission path between an accommodation station and an antenna site.

[0056] The required bandwidth of the transmission path varies depending on the base station function layout. Specifically, a C-RAN layout requires a large bandwidth of the transmission path, an S-RAN layout requires a medium-large bandwidth of the transmission path, and a D-RAN layout requires a small bandwidth of the transmission path. For this reason, when a transmission path between a storage station and an antenna site is shared by multiple cells, the overall required bandwidth of the transmission path changes depending on the combination of base station function layouts of each cell. For this reason, a single cell group is formed from multiple cells that share the same transmission path.

[0057] In Fig. 9, three cells belonging to cell group A (group ID = GID1) share a transmission path 401 between the accommodating station and the antenna site. Also, four cells belonging to cell group B (group ID = GID2) share a transmission path 402 between the accommodating station and the antenna site. As a result, the three cells sharing the same transmission path 401 are determined to be cell group A (group ID = GID1). On the other hand, the four cells sharing the same transmission path 402 are determined to be cell group B (group ID = GID2).

[0058] According to example 1 of the cell group determination method, as illustrated in FIG. 10, the bandwidth utilization rate can be appropriately adjusted and robustness against traffic fluctuations can be achieved by sequentially changing the base station function arrangement in multiple cells (Cell#1, Cell#2, Cell#3) belonging to the same cell group to avoid congestion based on the observed value of the overall bandwidth utilization rate of the transmission path shared by the multiple cells.

[0059] (Example 2 of cell group determination method) FIG. 11 is an explanatory diagram of Example 2 of the cell group determination method according to this embodiment. In Example 2 of the cell group determination method, a cell group is composed of a plurality of cells that satisfy a predetermined radio wave influence criterion. For example, the radio wave influence criterion is that the cell spacing is within a predetermined distance. The radio wave influence criterion may be that the influence of radio waves is equal to or greater than a predetermined criterion. For example, the radio wave influence criterion is that the received signal strength indicator (RSSI) is equal to or greater than a reference value.

[0060] CoMP is a technology that can improve wireless communication quality at cell edges where radio interference is strong by transmitting radio waves from multiple antennas in a coordinated manner. Whether or not inter-cell cooperation can be used depends on the base station function arrangement. Specifically, inter-cell cooperation can be used in C-RAN arrangements, but inter-cell cooperation cannot be used in S-RAN and D-RAN arrangements. Therefore, even if a certain cell can use inter-cell cooperation, whether or not a terminal located at the cell edge of the cell can use inter-cell cooperation depends on the base station function arrangement of the surrounding cells of the cell. For this reason, a cell group is formed from multiple cells that satisfy a specified radio wave influence standard.

[0061] In Fig. 11, the four cells belonging to cell group C (group ID = GID3) have cell intervals within a predetermined distance. Also, the four cells belonging to cell group D (group ID = GID4) have cell intervals within a predetermined distance. This determines cell group C (group ID = GID3) and cell group D (group ID = GID4), each consisting of four cells.

[0062] According to the example 2 of the cell group determination method, a certain cell can change the arrangement of base station functions between cells so that inter-cell cooperation can be efficiently used, taking into consideration the movement of users (terminals) and the radio environment, based on whether or not inter-cell cooperation of neighboring cells is available. For example, in FIG. 12, since the neighboring cell (Cell#12) of the cell (Cell#11) is in a C-RAN arrangement, if the cell (Cell#11) changes its own cell to a C-RAN arrangement, the terminal UE2 can use inter-cell cooperation. On the other hand, since the neighboring cell (Cell#14) of the cell (Cell#11) is in an S-RAN arrangement, the terminal UE1 cannot use inter-cell cooperation even if the cell (Cell#11) changes its own cell to a C-RAN arrangement.

[0063] As described above, according to this embodiment, it is possible to obtain an effect that the execution of base station function placement can be appropriately controlled in a radio access network (RAN1) conforming to the O-RAN specifications.

[0064] According to this embodiment, the timing of changing the base station function allocation for each cell belonging to a cell group is shifted for each cell group to which a plurality of cells included in RAN 1 belong. This makes it possible to reflect the result of changing the base station function allocation of a cell in the same cell group in the change of the base station function allocation of other cells.

[0065] According to this embodiment, when determining the base station function allocation by distributed reinforcement learning, an "Actor" can observe changes in the network state due to the actions of other "Actors" and act accordingly. Meanwhile, at the timing of relocation of each cell, only the cell at the timing of relocation changes its base station function allocation. Therefore, at the timing of relocation of a certain cell, only the action of the "Actor" corresponding to that cell affects the network state, and the network can be controlled by the action of the "Actor" itself.

[0066] This will, for example, make it possible to improve the overall service quality in wireless access networks, thereby contributing to Goal 9 of the United Nations' Sustainable Development Goals (SDGs), which is to "Build resilient infrastructure, promote sustainable industrialization and foster innovation."

[0067] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like that do not deviate from the gist of the present invention are also included.

[0068] In addition, a computer program for implementing the functions of each of the above-mentioned devices may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read into a computer system and executed. Note that the "computer system" referred to here may include hardware such as an OS and peripheral devices. In addition, the term "computer-readable recording medium" refers to writable non-volatile memory such as a flexible disk, an optical magnetic disk, a ROM, or a flash memory, a portable medium such as a DVD (Digital Versatile Disc), or a storage device such as a hard disk built into a computer system.

[0069] Furthermore, the term "computer-readable recording medium" includes devices that retain a program for a certain period of time, such as volatile memory (e.g., DRAM (Dynamic Random Access Memory)) within a computer system that serves as a server or client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. The program may be transmitted from a computer system in which the program is stored in a storage device or the like to another computer system via a transmission medium, or by a transmission wave in the transmission medium. Here, the "transmission medium" that transmits the program refers to a medium that has a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for implementing some of the functions described above, or may be a so-called differential file (differential program) that can implement the functions described above in combination with a program already recorded in the computer system. [Explanation of symbols]

[0070] 1...Radio Access Network (RAN), 2...Base Station Function Group, 10...SMO Framework, 11...SMO Function Unit, 12...Non-RT RIC, 20...Base Station Function Arrangement Control Unit, 220...Cell Group Information Storage Unit, 203...KPI Acquisition Unit, 204...Base Station Function Arrangement Setting Information Transmission Unit, 205...Control Unit

Claims

1. a cell group information storage unit configured to store cell group information indicating a cell group to which a plurality of cells included in a radio access network conforming to the O-RAN specification belong; A control unit that shifts a timing of changing the base station function allocation for each cell belonging to one of the cell groups; Equipped with The cell group is composed of a plurality of cells sharing the same transmission path, the transmission path is a transmission path between an accommodation station and an antenna site, The required bandwidth of the transmission path varies depending on the base station function layout, the control unit sequentially changes the base station function allocation in the plurality of cells so as to avoid congestion based on an observed value of an overall bandwidth utilization rate of a transmission path shared by the plurality of cells belonging to the same cell group. Base station function arrangement control device.

2. The cell group is composed of a plurality of cells that satisfy a predetermined radio wave influence criterion. The base station function arrangement control device according to claim 1.

3. The radio wave influence criterion is that the cell interval is within a predetermined distance. The base station function arrangement control device according to claim 2.

4. The radio wave influence standard is that the influence of radio waves is equal to or greater than a predetermined standard. The base station function arrangement control device according to claim 2.

5. The control unit determines a base station function allocation for each cell included in the radio access network by distributed reinforcement learning. The base station function arrangement control device according to any one of claims 1 to 4.

6. The base station function arrangement control device is realized using a "Non-RT RIC (Non-Real Time RAN Intelligent Controller)". The base station function arrangement control device according to any one of claims 1 to 5.

7. A base station function arrangement control method in an O-RAN radio access network, comprising: a cell group information storage step in which the base station function arrangement control device stores cell group information indicating a cell group to which a plurality of cells included in the radio access network of the O-RAN specification belong; a control step of the base station function arrangement control device shifting a timing of changing the arrangement of base station functions for each cell belonging to one of the cell groups; Including, The cell group is composed of a plurality of cells sharing the same transmission path, the transmission path is a transmission path between an accommodation station and an antenna site, The required bandwidth of the transmission path varies depending on the base station function layout, the control step sequentially changes the base station function allocation in the plurality of cells so as to avoid congestion based on an observed value of an overall bandwidth utilization rate of a transmission path shared by the plurality of cells belonging to the same cell group; A base station function arrangement control method.

8. The computer of the base station function arrangement control device A cell group information storage step of storing cell group information indicating a cell group to which a plurality of cells included in a radio access network conforming to the O-RAN specification belong; A control step of shifting the timing of changing the base station function allocation for each cell belonging to one of the cell groups; Run the command, The cell group is composed of a plurality of cells sharing the same transmission path, the transmission path is a transmission path between an accommodation station and an antenna site, The required bandwidth of the transmission path varies depending on the base station function layout, the control step sequentially changes the base station function allocation in the plurality of cells so as to avoid congestion based on an observed value of an overall bandwidth utilization rate of a transmission path shared by the plurality of cells belonging to the same cell group; Computer program.

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