Control device for controlling radio resource in o-ran, control method, and program

Abstract

To provide a control device, a method, and a program for improving communication quality.SOLUTION: A control device of a communication system using an O-RAN (Open-Radio Access Network), which provides a plurality of cells sharing a predetermined range of frequency resources, identifies a first cell included in the plurality of cells and a plurality of other cells around the first cell, acquires information capable of identifying a use amount of a radio resource in each of the first cell and the other cells, selects one or more second cells included in another cell such that a sum of the use amount of the radio resources in the first cell and the use amount of the radio resources in the one or more second cells does not exceed a predetermined threshold value, sets a range of the frequency resources preferentially usable by the first cell and the range of frequency resources preferentially usable by the second cell to be at least partially different from each other among frequency resources in a predetermined range, and notifies a processing device of information capable of specifying the range of each set frequency resource.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a technique for controlling radio resources in an O-RAN (Open-Radio Access Network). [Background technology]

[0002] With the increasing popularity of wireless communication services, it has become common for users to communicate wirelessly in a variety of environments. For example, in event venues such as concert halls and sports facilities such as stadiums, a large number of users communicate in a given area covered by multiple cells. In addition, the 3rd Generation Partnership Project (3GPP) cellular communication standard has been formulated to accommodate various types of communication services on a single network by configuring network slices (slice), and the communication quality required to provide communication services can be associated with a specific cell or slice.

[0003] In order to efficiently provide wireless communication services while maintaining communication quality in such an environment, it is necessary to optimize the operation of the wireless communication system while monitoring communication quality. For such wireless communication systems, development is underway to collect and analyze information on communication quality in cells to perform advanced RAN (Radio Access Network) control. For example, the standardization of O-RAN (Open-RAN), which makes the Radio Access Network (RAN) open and intelligent, defines a RAN Intelligent Controller (RIC) for intelligently configuring and operating the RAN (Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] O-RAN Working Group 2, “Non-RT RIC Architecture”, O-RAN Alliance, 2023 Summary of the Invention [Problem to be solved by the invention]

[0005] In an environment where multiple cells using the same band are deployed closely in a given area, interference between the cells is likely to degrade communication quality. In particular, when frequency resources are shared by the cells, the likelihood of interference increases. The present invention provides a technology for improving communication quality of RAN in a communication system using O-RAN. [Means for solving the problem]

[0006] A control device according to one embodiment of the present invention is a control device that functions as a RAN Intelligent Controller (RIC) in an Open-Radio Access Network (O-RAN) that provides multiple cells that share a predetermined range of frequency resources, and includes: an identification means for identifying a first cell included in the multiple cells and one or more other cells surrounding the first cell included in the multiple cells; an acquisition means for acquiring information that can identify the amount of radio resources used in each of the first cell and the other cells; a selection means for selecting one or more second cells included in the other cells such that the sum of the amount of radio resources used in the first cell and the amount of radio resources used in the one or more second cells does not exceed a predetermined threshold; a setting means for setting, among the predetermined range of frequency resources, a range of frequency resources that the first cell can preferentially use and a range of frequency resources that the second cell can preferentially use so that at least a portion of them are different; and a notification means for notifying a processing device that executes radio resource allocation in each of the first cell and the second cell of the information that can identify the ranges of the frequency resources set by the setting means. [Effects of the Invention]

[0007] According to the present invention, in a communication system using O-RAN, it is possible to improve the communication quality of the RAN. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 illustrates an example of the configuration of a communication system. [Figure 2] FIG. 10 is a diagram illustrating an example of a processing flow of the RIC. [Figure 3] FIG. 1 is a diagram illustrating an example of an arrangement of multiple cells in a communication system. [Figure 4] FIG. 2 is a diagram illustrating an example of the hardware configuration of a RIC and a DU. [Figure 5] FIG. 2 is a diagram illustrating an example of the functional configuration of a RIC. [Figure 6] FIG. 2 is a diagram illustrating an example of the functional configuration of a DU. [Figure 7] FIG. 10 is a diagram illustrating an example of the flow of processing executed by the RIC and the DU. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention as claimed, and not all combinations of features described in the embodiments are necessarily essential to the invention. Two or more of the features described in the embodiments may be arbitrarily combined. Furthermore, the same reference numerals are used for the same or similar components, and redundant explanations will be omitted.

[0010] (System Configuration) FIG. 1 shows an example of the configuration of a communication system according to this embodiment. This communication system is configured using an Open-Radio Access Network (O-RAN), which is being standardized to make the Radio Access Network (RAN) open and intelligent. The O-RAN includes, for example, a RAN Intelligent Controller (RIC) 101, a Distributed Unit (DU) 102, Radio Units (RUs) 111 to 114, and User Equipment (UEs) 121 to 128. In this embodiment, the RUs 111 to 114 may be collectively referred to as RU 110. Also, in this embodiment, the UEs 121 to 128 may be collectively referred to as UE 120. Note that while FIG. 1 shows an example in which one DU 102 is connected to four RUs 111 to 114 via a wired network, there may be two or more DUs 102, and in that case, each RU 110 may be connected to a different DU 102. Similarly, the number of RUs 110 connected to a DU 102 may be one, two, three, or five or more. Furthermore, the number of UEs 120 connected to each RU 110 may be zero or more, and one terminal 100 may be simultaneously connected to multiple base stations 110. The devices may be interconnected via a wired network or a wireless network. In FIG. 1, solid lines indicate that the devices are connected via a wired network. An area in which communication with each RU 110 via a wireless medium is possible may be called a cell. For example, RUs 111 to 114 constitute cells 131 to 134. In FIG. 1, each UE 120 included within the range of the dotted lines indicating each cell 131 to 134 can communicate with each of the RUs 110 constituting that cell. The cells 131 to 134 may have spatially overlapping areas. Cells 131 to 134 may be collectively referred to as cell 130.

[0011] The RIC 101 designs and configures RAN parameters, automates and optimizes RAN operations, and performs other functions. The RIC 101 may include a non-real-time RIC and a near-real-time RIC, as defined in the O-RAN standard. The non-real-time RIC may determine policies for controlling the long-term behavior of the entire system. The near-real-time RIC may control the RAN in accordance with policies generated by the non-real-time RIC. For example, the RIC 101 controls the RAN by providing information necessary for the DU 102 to schedule the cell associated with the RIC 101. The DU 102 and the RU 110 cooperate with each other to perform RAN functions. The DU 102 has functions such as media access control (MAC) for allocating radio resources in the RAN and radio link control (RLC) for controlling retransmissions. For example, the DU 102 has a function for allocating radio resources (scheduling) to the UE 120 connected to the cell associated with the DU 101. The RU 110 performs a wireless physical layer function for transmitting and receiving wireless signals to and from the UE 120 connected to a cell provided by the RU 110. The UE 120 transmits and receives wireless signals to and from the RU 110 using wireless resources allocated by the DU 102. The UE 120 includes, for example, a smartphone, a mobile phone, a personal computer, a tablet terminal, a wearable terminal, an IoT (Internet of Things) terminal, and the like. Note that the communication system in this embodiment may include a Central Unit (CU) (not shown). The CU may have functions such as PDCP (Packet Data Convergence Protocol) for packet encryption and RRC (Radio Resource Control).

[0012] The RIC 101 may acquire various data stored in the DU 102 from the DU 102. The RIC 101 may acquire the various data stored in the DU 102 directly from the DU 102 or via another device such as an Element Management System (EMS). For example, the DU 102 may determine the received signal strength indicator (RSSI) and the amount of interference in each cell based on a signal received from the RU 110 associated with the DU 102 and information acquired from the UE 120 connected to the cell served by the RU 110. For example, the RU 110 may calculate the RSSI using a reference signal received from the UE 120. The DU 102 may also determine the communication volume in each cell based on the allocation status of radio resources to each UE in the scheduling function executed by the DU 102. The information that the DU 102 can acquire is not limited to this information. Meanwhile, the RIC 101 may perform advanced analysis using the data acquired from the DU 102, optimize RAN configuration parameters using the analysis results, and control the DU 102 using these configuration parameters. For example, the RIC 101 can analyze information acquired from the DU 102 to calculate statistical information such as the average communication volume and interference volume of each cell, and use this statistical information to generate information necessary for scheduling in each cell and notify the DU 102. As communication interfaces for executing such communication between the RIC 101 and the DU 102, for example, the O1 interface, the E2 interface, etc. are specified in the O-RAN Alliance, which promotes the standardization of O-RAN.

[0013] A cell provided by each RU 110 is assigned a predetermined frequency band that the cell can use for wireless communication. This frequency band may be called a system band. The system band may be different for each cell, may be the same between cells, or may partially overlap. The system band for each cell may be fixedly set by an operator that manages and operates the communication system, or may be dynamically set by a control device in the communication system, such as the RIC 101. In this embodiment, it is assumed that the same system band is assigned to each cell provided by the RUs 111 to 114. In scheduling of the cell associated with the DU 102, for example, based on a resource allocation request received from the UE 120, the DU 102 allocates radio resources within the system band of the cell to which the UE 120 is connected to the UE 120. Furthermore, when data addressed to the UE 120 arrives from a network (not shown), the DU 102 allocates radio resources necessary to transmit the data to the UE 120. The unit of radio resources allocated to each UE 120 may be called a physical resource block (PRB). For example, a PRB is a frequency and time resource defined by 12 subcarriers on the frequency axis and one subframe (1 millisecond) on the time axis. That is, when performing scheduling within one radio frame, the DU 102 divides the system band into bands of 12 subcarriers on the frequency axis based on the PRB, divides one radio frame (10 milliseconds) into subframes of 1 millisecond on the time axis, and can perform allocation to each UE 120 in units of PRB.

[0014] As described above, the DU 102 performs scheduling based on a resource allocation request from the UE 120 or based on the arrival of data from the network to the UE 120. At this time, there is a possibility that PRBs with the same allocation on the frequency axis and the time axis are allocated to multiple UEs 120 connected to different cells. For example, as shown in FIG. 1, even when multiple RUs 110 are connected to one DU 102, the DU 102 may treat radio resources as if each cell were independent of the other. In this case, for example, if the DU 102 applies the same algorithm to scheduling for each cell, PRBs with the same allocation on the frequency axis and the time axis in a radio frame may be allocated to multiple UEs 120 connected to different cells. For example, the DU 102 may apply a scheduling algorithm to each cell independently, in which the lowest-frequency PRB in the first subframe of a radio frame is used as the starting position for radio resource allocation, and PRBs are allocated to higher-frequency or later-time PRBs. In this case, there is a high possibility that interference between cells will occur in each PRB. Furthermore, when multiple RUs 110 sharing the same system band are connected to different DUs, each DU may not consider the placement of PRBs in the radio frame used in cells other than its own cell when scheduling. In this way, if multiple cells use PRBs with the same placement on the frequency axis and time axis in the radio frame, mutual interference may occur between the PRBs if these cells are not sufficiently separated spatially. Radio signals transmitted using PRBs affected by interference are more likely to be improperly received, which may lead to degradation of communication quality, such as reduced throughput and traffic delays.

[0015] In particular, the 3rd Generation Partnership Project (3GPP) cellular communication standard specifies that various types of communication services can be accommodated on a single network by configuring network slices (slices). Slices are a technology that virtually divides a physical network according to services and accommodates various requirements for communication quality. For example, communication traffic transmitted through a network can be identified by an identifier (e.g., Single-Network Slice Selection Assistance Information, S-NSSAI) assigned to each slice. When a specific communication service is provided using a slice, the communication quality (required quality) required to provide the specific communication service can be associated with a specific cell or slice. For example, to provide a communication service that guarantees a predetermined latency, it may be necessary to secure allocation of a predetermined amount of radio resources to a slice corresponding to the communication service and a cell to which a UE communicating through the slice is connected. In this case, in an open environment such as outdoors, a large number of cells may be arranged around a specific cell associated with a required quality. Therefore, if the surrounding cells use radio resources that have the same arrangement on the frequency axis and the time axis as the radio resources reserved for a specific communication service, this may result in a deterioration in communication quality due to interference, which may make it impossible to provide the communication quality that should be guaranteed, or may increase the amount of radio resources that should be reserved to guarantee the communication quality.

[0016] In this embodiment, in consideration of such circumstances, the RIC 101 sets a range of frequency resources that can be preferentially used by each of a specific first cell and one or more surrounding second cells, and provides the range to the DU 102. The range of frequency resources that can be preferentially used by the first cell is set to be at least partially different from the range of frequency resources that can be preferentially used by the second cell. The DU 102 allocates radio resources to the UE 120 connected to the cell associated with the DU 102 based on the range of frequency resources that can be preferentially used by each cell provided by the RIC 101. When allocating radio resources to the UE 120 connected to a certain cell, if there are any unallocated radio resources in the range of frequency resources that can be preferentially used by the cell, the DU 102 preferentially allocates the radio resources. On the other hand, if there are no allocable radio resources in the range of frequency resources that can be preferentially used by the cell, the DU 102 allocates radio resources in other frequency resource ranges in the system band to the UE 120. In this way, by configuring the range of frequency resources that the first cell and one or more second cells can use preferentially to be different, it becomes possible to protect the radio resources reserved in the first cell for communications for which communication quality must be guaranteed from interference from other surrounding cells.

[0017] The RIC 101 may identify a first cell and a second cell for which a frequency resource range should be set based on the amount of frequency resources used in each cell. For example, the RIC 101 may acquire information that can identify the amount of radio resources used in each cell and select the first cell and one or more second cells so that the sum of the amount of radio resources used in each cell does not exceed a predetermined threshold. The information that can identify the amount of radio resources used may be the amount of radio resources used in each cell within a predetermined period. The radio resources are, for example, PRBs. Alternatively, the information that can identify the amount of radio resources used may be the radio resource usage rate in each cell. The radio resource usage rate may be, for example, the number of radio resources actually used (allocated) relative to the total number of radio resources available for communication using the entire system band. When the amount of radio resources used is specified by the number of radio resources, the predetermined threshold may be the total number of radio resources available for communication using the entire system band. Note that when the amount of radio resources used is specified by the radio resource usage rate, the predetermined threshold may be 100 (%) or a predetermined percentage (%) when the amount of radio resources available for communication using the entire system band is set to 100. The information that can identify the amount of radio resources used may be information other than the above, such as the number of UEs 120 in each cell or the amount of communication traffic.

[0018] The RIC 101 may also select the second cell based on the magnitude of the interference that each cell has on the first cell. For example, the RIC 101 may preferentially select a cell as the second cell if the interference that each cell has on the first cell is greater. This makes it possible to reduce the influence of a cell that is likely to cause significant interference on radio resources reserved for communication in the first cell, whose communication quality must be guaranteed. As an example, the RIC 101 may prioritize a cell that has a significant interference effect on the first cell and select the second cell so that the sum of the radio resource usage amounts of the first cell and one or more second cells does not exceed a predetermined threshold. In an open environment, many cells may be deployed around the first cell. Therefore, if frequency resource ranges are set for each cell for all cells, the range of frequency resources that each cell can preferentially use will be smaller, resulting in a high possibility that the radio resources reserved for communication in the first cell, whose communication quality must be guaranteed, will not be protected. By selecting a cell to be set based on the magnitude of the influence of interference from each cell and the amount of radio resources used in each cell, the setting is made so that each selected cell can communicate within the range of frequency resources that can be used preferentially, and interference from cells that have a large influence on the first cell is reduced, so that the radio resources reserved for communication in the first cell for which communication quality should be guaranteed can be appropriately protected. Below, the operation of each device in the radio resource allocation process according to this embodiment will be described.

[0019] (Identifying the cell to be set) 2 shows an example of an operation flow executed by the RIC 101. First, the RIC 101 identifies a cell (first cell) having radio resources to be protected (S201). For example, the RIC 101 identifies, as the first cell, a cell in which a terminal 120 that performs communication of a slice corresponding to a communication service with a predetermined requirement for communication quality is located. As an example, the RIC 101 determines whether or not there is a cell in which radio resources (PRB, etc.) for communication of a specific slice are reserved in advance (for example, a specific radio resource is associated with a specific slice). When the RIC 101 detects a cell in which radio resources for communication of a specific slice are reserved, it can identify the cell as the first cell.

[0020] After identifying the first cell, the RIC 101 identifies a candidate second cell that may cause interference with the first cell (S202). For example, the RIC 101 may acquire information for identifying a candidate second cell that may cause interference with the first cell from each network device including the DU 102. The information for identifying a candidate second cell that may cause interference with the first cell may be, for example, the amount of radio resource usage, usage rate, and amount of interference in each cell, and cell location information (such as the latitude and longitude of the location where the RUs 110 constituting the cell are located). For example, the RIC 101 may acquire statistical information such as the amount of radio resource usage, usage rate, and amount of interference in each cell from the DU 102 via the E2 interface or the O1 interface. The RIC 101 may also acquire cell location information from the EMS. As an example, the RIC 101 may identify a candidate second cell based on the correlation between the amount of interference in the first cell and the amount of radio resource usage in each other cell. For example, if the increase in the amount of interference in the first cell is large when the amount of radio resource usage in another cell increases by a certain amount, the RIC 101 may identify the other cell as a candidate for the second cell. That is, if there is a positive correlation between the increase in the amount of interference in the first cell and the increase in the amount of radio resource usage in the other cell, communication in the other cell may be causing interference in the first cell. The amount of interference may be, for example, the received signal strength indicator (RSSI) of a received interfering signal, the length of time the interfering signal is received, or a combination of these. A large amount of interference may be, for example, when the RSSI of the interfering signal is greater than a predetermined threshold or when the period during which the interfering signal is detected is longer than a predetermined threshold. Furthermore, based on the location information of the RUs 110 in the vicinity of the first cell, the RIC 101 may identify, as a candidate for the second cell, a cell formed by RUs 110 located within a predetermined distance from the location of the RUs 110 that constitute the first cell. Communication in a cell that is spatially close to the first cell may cause interference to the first cell. The method by which the RIC 101 identifies the second cell candidate is not limited to the above.For example, the RIC 101 may acquire from the DU 101 the number of handover attempts between each cell and the first cell within a unit time, and identify a cell for which the number of handover attempts exceeds a predetermined threshold as a candidate for the second cell. A handover attempt may be performed when a terminal 120 is present at the boundary between the cells. In particular, when a handover is attempted between another cell and the first cell, there is a high possibility that a terminal 120 is present at the boundary between that cell and the first cell. A terminal 120 located in such a position and connected to another cell is likely to cause interference to the first cell.

[0021] The RIC 101 determines, from the identified first cell and second cell candidates, a plurality of cells for which the range of frequency resources that each cell can preferentially use is to be set (S203). That is, the RIC 101 determines, from the second cell candidates, a second cell to be set as a setting target. For example, the RIC 101 may determine the setting target cell based on the radio resource usage of the identified first cell and the radio resource usage of each of the second cell candidates and the magnitude of the influence of interference on the first cell. The magnitude of the influence of interference on the first cell by the second cell candidate may be the strength or amount of interference that the second cell candidate causes to the first cell. For example, the higher the RSSI of a transmission signal from the second cell candidate received by the first cell, the higher the correlation between an increase in the amount of interference in the first cell and an increase in the amount of radio resource usage in the second cell candidate, and the shorter the spatial distance between the first cell and the second cell, the higher the evaluation value. Note that the degree of influence on the first cell may be evaluated using a method other than these, as long as it is a method capable of evaluating the strength and amount of interference from the second cell candidate to the first cell. The RIC 101 may assign a ranking (priority) to each of the second cell candidates based on the result of evaluating the magnitude of the influence of each of the second cell candidates on the first cell. For example, the RIC 101 may assign a higher ranking to the candidate second cell, the greater the influence of interference on the first cell from the candidate second cell. For example, the RIC 101 may assign a higher ranking to the candidate second cell, the greater the increase in the amount of interference in the first cell when the usage amount of radio resources in the candidate second cell increases by a certain amount, since this indicates a higher positive correlation. This ranking may be used to determine the second candidate from among the candidate second cells.

[0022] The RIC 101 may determine one or more second cells so that the sum of the radio resource usage amount of the first cell and the radio resource usage rate of one or more second cells does not exceed a predetermined threshold (S204). The radio resource usage amount may be an average or maximum value of the usage rate of PRBs used in each cell during a predetermined past period. Alternatively, it may be an estimated value of the radio resource usage amount of each cell in the future, estimated based on the trend of the radio resource usage amount in the past. The radio resource usage amount of each cell may be specified based on scheduling information of the radio resources allocated to each cell by the DU 102 or the like. The radio resource usage amount may be estimated based on the past communication volume in each cell. The RIC 101 then calculates the sum of the radio resource usage amount of the first cell and the radio resource usage amount of the second cell candidate, while selecting the second cell candidate from the highest ranked candidate. The RIC 101 may then determine, as the configuration target, the combination of the first cell and the second cell candidate immediately before the sum exceeds the predetermined threshold. In this way, by using a combination of the first cell and a second cell candidate that is ranked higher to select a cell for which a frequency resource range is to be set, it is possible to mitigate interference from a cell that has a large influence on the first cell. The method by which the RIC 101 determines the second cell is not limited to this method. For example, the RIC 101 may calculate the sum of the amount of radio resources used by the first cell and the amount of radio resources used by the second cell candidate while randomly selecting cells from among those ranked from the top to a predetermined rank. Then, the RIC 101 may determine, as the setting target, the combination of the first cell and the second cell candidate that is immediately before the sum exceeds a predetermined threshold. The method by which the RIC 101 selects the second cell is not limited to this, and it is sufficient that the second cell be determined so that the sum of the amount of radio resources used by the first cell and the amount of radio resources used by the second cell does not exceed a predetermined threshold. The RIC 101 sets, for the selected first cell and second cell, frequency resource ranges that can be used preferentially by each of the selected first cell and second cell (S205). The setting of the range of frequency resources by the RIC 101 will be described later.

[0023] FIG. 3 shows an example of the operation of the RIC 101 when identifying a first cell and a second cell. FIG. 3 shows an example of the spatial arrangement of multiple cells 301 to 308 included in the communication system of this embodiment. It is assumed that the cell 301 is a cell identified by the RIC 101 as the first cell. That is, it is assumed that a terminal 120 performing communication of a slice corresponding to a predetermined communication service is present in the cell 301. In this case, the RIC 101 first identifies the cell 301 as the first cell. Next, the RIC 101 identifies, for example, cells in the periphery of the cell 301 (for example, cells formed by RUs 110 included within a predetermined distance from the RUs 110 that form the cell 301) as candidates for the second cell. At this time, cell 308 that is far from the first cell (for example, if the predetermined distance is 300 m, and RU 110 that constitutes cell 308 is more than 300 m away from RU 110 that constitutes cell 301) is excluded from the candidates for the second cell, and cells 302 to 307 may be identified as candidates for the second cell. Then, RIC 101 generates a ranking of the magnitude of the impact of interference on cell 301 for each of cells 302 to 307. Cell 301 may generate a ranking of the magnitude of the impact of interference based on, for example, the RSSI of the interference power from each of cells 302 to 307. Here, it is assumed that cells 302 to 307 have the highest ranking. RIC 101 adds up the PRB usage amounts of cell 301 and cells 302 to 307 in order. For example, suppose that the PRB usage amount is determined based on the total number of PRBs available for communication using the entire system band, and that the PRB usage rates of cells 301 to 308 are 30%, 20%, 20%, 30%, 30%, 20%, 20%, and 50%, respectively. Furthermore, suppose that the threshold for PRB usage is 100%. In this case, by calculating the sum of the PRB usage rates of each cell in order starting from cell 301, the sum of the PRB usage rates of cells 301 to 304 is 100%, and the sum of the PRB usage rates of cells 301 to 305 is 130%. Therefore, RIC 101 determines cells 301 to 304, which are a combination of cells that does not exceed the threshold, as targets for setting the frequency resource range.

[0024] (Setting the range of frequency resources that each cell can use preferentially) After determining the target cells, the RIC 101 executes processing to set a frequency resource range for each cell. For example, the RIC 101 may set a frequency resource range that each cell can use preferentially based on the amount of radio resources used and the amount of communication in each cell. As an example, a description will be given of a case in which the RIC 101 sets the frequency resource range based on the ratio of the amount of radio resources used in each cell. The RIC 101 may calculate the ratio of the amount of radio resources used in each cell based on the amount of radio resources used in each cell. For example, if the average values ​​of PRB usage rates in cells 131 to 134, which are formed by each of RUs 111 to 114, over a certain period of time are U1 to U4, respectively, the RIC 101 may calculate the ratio of the amount of radio resources used in each cell as U1:U2:U3:U4. For example, if the average communication traffic volume in cells 131 to 134 during a certain period is Tr1 to Tr4, respectively, the RIC 101 may calculate the ratio of the usage volume of radio resources in each cell as Tr1:Tr2:Tr3:Tr4. The RIC 101 may calculate the ratio of the usage volume of radio resources in each cell using the number of PRBs used by each cell notified by the DU 102 or the number of PRBs allocated to each cell. The DU 102 may provide the RIC 101 with information specifying fluctuations in communication volume such as maximum and minimum values, standard deviation, and variance of PRB usage volume of each cell during a predetermined period, as well as the amount of interference each cell receives from other cells.

[0025] Then, the RIC 101 sets a range of frequency resources that each cell can use preferentially based on the ratio of the amount of radio resources used in each cell. In this embodiment, the frequency resources may be a predetermined frequency band. For example, the RIC 101 may set a range of frequency resources for each cell so that the range of frequency resources set for each cell differs from one another. Based on the ratio of the amount of radio resources used in each cell, the RIC 101 may set a wide range of frequency resources for cells with a high ratio of radio resource usage and a narrow range of frequency resources for cells with a low ratio of radio resource usage. By setting a wide range of frequency resources for cells with a high communication volume, the possibility of a shortage of PRBs within that range of frequency resources during scheduling in the DU 102 may be reduced. As an example, if the ratio of radio resource usage in cells 131 to 134 obtained from DU102 is U1:U2:U3:U4, RIC101 can divide the system band into four so that the ratio of each band is U1:U2:U3:U4, and set each of the four frequency bands as a range of frequency resources that can be used preferentially by the cells provided by each of RU111 to RU114.

[0026] Furthermore, the RIC 101 may set frequency resource ranges for each cell so that the ranges of frequency resources set for each cell partially overlap. For example, the RIC 101 may set a different frequency for each cell as the lower end of the range of frequency resources that can be preferentially used for each cell, and set the upper end of the system band as a common upper end. For example, the lower end frequencies of the frequency resource ranges set for each cell may be lower in the order of RU 111, RU 112, RU 113, and RU 114. In this case, for example, in the frequency resource range set for RU 111, the higher the frequency, the more RUs 110 that use the same frequency resource. However, the possibility of interference is reduced compared to when all cells use the same frequency resource. In this case, the RIC 101 may notify the DU 102 of only the lower end of the frequency resource range set for each cell. Note that the RIC 101 may set a different frequency for each cell as the upper end of the range of frequency resources that can be preferentially used for each cell, and set the upper end of the system band as a common lower end.

[0027] The RIC 101 arranges frequency resources to be set for each cell on a frequency axis. For example, the RIC 101 may arrange frequency resources to be set for a first cell in a frequency band that is less susceptible to interference from other cells. Since the ranges of frequency resources that each cell is targeted for setting a frequency resource range for by the RIC 101 differ, the possibility of mutual interference is reduced. On the other hand, there is a possibility that interference may occur with the first cell from cells other than the target for setting a frequency resource range. For example, when radio resources are allocated to each cell starting from the lowest frequency, the RIC 101 may arrange frequency resources to be set for the first cell in a high-frequency band. This may reduce the possibility that the first cell will be interfered with by cells other than the target for setting a frequency resource range in this embodiment. Furthermore, the RIC 101 may arrange frequency resources to be set for the first cell on a frequency axis based on the past radio resource allocation status for each cell. For example, the RIC 101 may compile past trends in the amount of radio resources used in each cell for each unit frequency band, and arrange frequency resources to be set for the first cell in a frequency band where the amount of radio resources used was relatively small. Furthermore, the RIC 101 may arrange the ranges of frequency resources to be set for each of the second cells on the frequency axis so that the wider the range of frequency resources to be set for a cell, the farther the cell is from the frequency resources set for the first cell. Generally, a cell with a high ratio of radio resource usage is likely to have a large temporal fluctuation in the radio resource usage compared to a cell with a low ratio of radio resource usage. Therefore, by arranging the cells with a high ratio of radio resource usage on the frequency axis so that they are farther from the range of frequency resources to be set for the first cell, the possibility that the range of frequency resources that the first cell can preferentially use will be used by the second cell can be reduced. Furthermore, the RIC 101 may arrange the ranges of frequency resources to be set for each cell on the frequency axis based on past trends in fluctuations in the radio resource usage of each of the second cells.For example, the RIC 101 may arrange the frequency resource ranges to be set for each second cell on the frequency axis so that the greater the fluctuation in the amount of radio resources used, the farther the cell is from the frequency resource range to be set for the first cell, thereby reducing the possibility that the frequency resource range that the first cell can use preferentially will be used by the second cell. Furthermore, the RIC 101 may arrange the frequency resource ranges to be set for each second cell on the frequency axis based on the magnitude of the impact of interference on the first cell. For example, the RIC 101 may arrange the frequency resource ranges to be set for each second cell on the frequency axis so that the greater the impact of interference on the first cell, the farther the cell is from the frequency resource range to be set for the first cell, thereby reducing the impact of interference that occurs when the second cell uses the frequency resource range that the first cell can use preferentially. Note that the method by which the RIC 101 arranges the frequency resource ranges to be set for each cell on the frequency axis is not limited to the above.

[0028] The RIC 101 notifies the DU 102 of the range of frequency resources that each cell to be set can use preferentially. The RIC 101 can notify the DU 102 of either the lower end or the upper end of the frequency resource range, or both. For example, the RIC 101 can notify the DU 102 of the frequency f start and the upper limit frequency f end The RIC 101 may notify the DU 102 of the range of frequency resources using the index of the PRB. For example, in the range of frequency resources, the index of the PRB corresponding to the lowest frequency is N. start , the index N of the PRB corresponding to the highest frequency end If the lower end of this frequency resource range is N start and the upper end is N end Here, N indicates the index of the PRB on the frequency axis. The RIC 101 may notify the DU 102 of a combination of the upper or lower end of the frequency resource range and the bandwidth. For example, the RIC 101 may notify the DU 102 of a frequency f start Or, a frequency f that indicates the upper end of the frequency resource range. end and f denotes the bandwidth widthThe RIC 101 may notify the DU 102 of the combination of the PRB index N , which indicates the lower end of the frequency resource range. start or PRB index N indicating the upper end of the frequency resource range end and N denotes the number of PRBs. width The RIC 101 may notify the DU 102 of the combination of the frequency resource and the center frequency f c The RIC 101 can notify the DU 102 of a combination of the frequency resource and the bandwidth. The RIC 101 can also notify the lower end or upper end of the frequency resource as a relative value (offset) based on the lower end or upper end of the system band. The RIC 101 can notify the DU 102 of the frequency resource of each set cell using the O1 interface or the E2 interface. For example, the RIC 101 can notify the DU 102 of a combination of an identifier (e.g., PCI) that identifies a cell and either or both of the lower end and upper end of the range of frequency resources set in the cell, or information that identifies the range of frequency resources.

[0029] The RIC 101 may change the second cell to be set as a control target. For example, the RIC 101 may periodically acquire information from the DU 102 that can identify the communication volume, the amount of interference, etc. of each cell, and change the second cell to be controlled based on this information. Generally, as the terminal 120 moves between multiple cells included in a communication system, the strength and amount of interference from each cell to the first cell may change. After identifying the first cell, the RIC 101 may periodically extract second cell candidates, determine the second cell from among them, and set a range of frequency resources that each cell can preferentially use, thereby flexibly changing the cell to be controlled in accordance with changes in the communication environment in each cell. Note that the RIC 101 may periodically change the cell to be controlled, or may change the cell to be set as a control target based on changes in the interference occurrence status in the first cell. For example, the RIC 101 may periodically acquire information that can identify the amount of interference received from the first cell, and initiate an operation to change the cell to be set as a control target when the amount of interference received exceeds a predetermined threshold. This reduces the load of periodically collecting information from each cell other than the setting target. Note that the operation when the RIC 101 changes the setting target cell is the same as that described above, and therefore a description thereof will be omitted.

[0030] (Radio resource allocation for each UE) The DU 102 performs scheduling for the UE 120 connected to the cell associated with the DU 102, based on the range of frequency resources that each cell can preferentially use, notified by the RIC 101. Note that the DU 102 performs scheduling for the target cell to be configured, notified by the RIC 101, based on the range of frequency resources that each cell can preferentially use, and for the other cells, performs scheduling using the band that the cell can use (for example, the entire system band). Here, scheduling for the target cell to be configured will be described. For example, it is assumed that the cells 131 to 134 in FIG. 1 are the target cells to be configured. That is, the cell 131 corresponds to the first cell 301 in FIG. 3, and the cells 132 to 134 correspond to the second cells 302 to 304 in FIG. 3, respectively. For example, the range of frequency resources that the cell 131 can preferentially use can be set to a high-frequency band. Then, the DU 102 can allocate high-frequency radio resources in the range of frequency resources set for the cell 131 to communications that should be protected preferentially (for example, communications corresponding to a slice). The DU 102 allocates radio resources included in the range of frequency resources set in each of the second cells to the UE 120 connected to the cell with priority. Furthermore, if there is no radio resource available for allocation within the range of frequency resources set in each cell, the DU 102 can allocate using radio resources in other frequency resource ranges included in the system band. As an example, first, the DU 102 acquires from the RIC 101 the range of frequency resources that each cell can use with priority. For example, the DU 102 acquires N as information specifying the range of frequency resources that each of the cells 131 to 134 can use with priority. start,1 =9, N start,2 =0, N start,3 =5, N start,4Assume that the DU 102 acquires N=7. Here, it is assumed that the system band is configured by PRBs of N=0 to 11. In this case, the DU 102 can interpret that frequency resource ranges of N=9 to 11, 0 to 4, 5 to 6, and 7 to 8 are set for the cells 131 to 134, respectively. That is, the DU 102 can interpret that, for two adjacent cells on the frequency axis, the lower end of the frequency resource range of the cell in which the frequency resource range of a higher frequency is set is the upper end of the frequency resource range of the other cell. Furthermore, the DU 102 can interpret the same information as above as frequency ranges of N=9 to 11, 0 to 11, 5 to 11, and 7 to 11 are set for the cells corresponding to the cells 131 to 134, respectively. In this case, the DU 102 can interpret that the upper end of the frequency resource range set for each cell is the upper end of the system band.

[0031] Then, DU102 schedules radio frames based on a resource allocation request from UE120, the arrival of data from the network to UE120, etc. For example, when DU102 receives a resource allocation request from UE121 (a UE that performs communication corresponding to the slice) connected to RU111, DU102 allocates to UE121 a PRB with a PRB index of N=11, which is at the top end of the range of frequency resources set in the cell corresponding to RU111. Similarly, when DU102 receives a resource allocation request from UE122 (a UE that is not a UE that performs communication corresponding to the slice), DU102 allocates to UE122 a PRB with a PRB index of N=9. Furthermore, when DU102 receives a resource allocation request from UE123 connected to RU112, DU102 allocates to UE123 a PRB with a PRB index of N=0, which is at the start position of the range of frequency resources set in the cell corresponding to RU112. In this way, in scheduling for different cells, the starting positions of the radio resources to be allocated are different, which can reduce the possibility that PRBs with the same allocation on the frequency axis and the time axis in the radio frame are used simultaneously in multiple cells. On the other hand, when a resource allocation request is received from UE 124 connected to RU 112 and PRBs with PRB indices N=0 to N=4 have already been assigned to other UEs 120 connected to the same cell, DU 102 can allocate a PRB with N=5 to UE 124. Note that at this time, DU 102 may have already allocated a PRB with N=5 to UE 125 based on a resource allocation request from UE 125 connected to RU 113. In this case, there is a possibility that the same PRB with N=5 is used simultaneously by UE 124 and UE 125, causing interference between them. However, since the PRBs that each cell preferentially uses are different in scheduling for each cell, the possibility of such interference occurring is sufficiently reduced. Communications that require higher priority protection are allocated radio resources in frequency bands that are separate from the frequency bands where interference may occur, thereby reducing the possibility of interference occurring.Although the present embodiment has been described with reference to an example in which one PRB is allocated to each UE 120, two or more PRBs may be allocated to each UE 120.

[0032] (Device configuration) Next, an example of the configuration of the RIC 101 and DU 102 as described above will be described. FIG. 4 is a diagram showing the hardware configuration of the RIC 101 and DU 102. In one example, the RIC 101 and DU 102 are configured to include a processor 401, a ROM 402, a RAM 403, a storage device 404, and a communication circuit 405. The processor 401 is a computer configured to include one or more processing circuits, such as a general-purpose CPU (Central Processing Unit) or an ASIC (Application Specific Integrated Circuit). The processor 401 reads and executes programs stored in the ROM 402 or the storage device 404, thereby performing overall processing of the device and each of the above-mentioned processes. The ROM 402 is a read-only memory that stores information such as programs and various parameters related to the processes executed by the RIC 101 and DU 102. The RAM 403 functions as a workspace when the processor 401 executes a program, and is a random access memory that stores temporary information. The storage device 404 is, for example, a removable external storage device. The communication circuit 405 includes, for example, a circuit for communicating with other devices. As an example, the communication circuit 405 may function as an O1 interface, an E2 interface, etc. Although one communication circuit 405 is shown in FIG. 2, each device may have multiple communication circuits.

[0033] FIG. 5 is a diagram illustrating an example of the functional configuration of the RIC 101. The RIC 101 includes, as its functions, a cell identification unit 501, an information acquisition unit 502, a cell selection unit 503, a frequency resource range setting unit 504, and a frequency resource range notification unit 505, for example. FIG. 5 illustrates the functional configuration of the RIC 101 of this embodiment, and, for example, omits the general configuration of a RIC. Note that these functional units can be realized, for example, by the processor 401 executing a program stored in the ROM 402 or the storage device 404 and controlling the communication circuit 405 as necessary. However, the present invention is not limited to this, and, for example, dedicated hardware for realizing each function may be provided.

[0034] The cell identification unit 501 identifies a first cell and other cells in its vicinity. For example, the cell identification unit 501 may identify as the first cell a cell in which a UE 120 performing communication of a slice corresponding to a specific communication service is located and for which reservation of radio resources for that communication is requested. The cell identification unit 501 may also identify other cells in the vicinity of the first cell as candidates for the second cell. For example, the cell identification unit 501 may acquire information capable of identifying the geographical location of the RUs 110 constituting each cell, and may identify a cell constituted by RUs 110 within a predetermined distance from the RU 110 constituting the first cell as a candidate for the second cell. The information acquisition unit 502 acquires information capable of identifying the amount of radio resources used in each cell. For example, the information acquisition unit 501 may acquire the amount and rate of PRB usage, the amount of communication traffic, etc. in each cell as information capable of identifying the amount of radio resources used in each cell. The radio resources are, for example, PRBs. The information acquisition unit 502 may acquire information capable of identifying the amount of radio resources used in each cell by communicating with the DU 102 using the O1 interface or the E2 interface realized by the communication circuit 405. The cell selection unit 503 may select a second cell. For example, the cell selection unit 503 may select a second cell such that the sum of the amount of radio resources used in the first cell and the amount of radio resources used in one or more second cells does not exceed a predetermined threshold. The cell selection unit 503 may also select a second cell based on the magnitude of interference that each of the second cell candidates has on the first cell. The frequency resource range setting unit 504 may set a range of frequency resources that each cell can preferentially use. For example, the frequency resource range setting unit 504 may identify the ratio of the amount of radio resources used in each cell and set a larger frequency resource range for a cell with a larger ratio of the amount of radio resources used. The frequency resource setting range unit 504 may also set the frequency resource range for each cell such that the range of frequency resources set for each cell is different from each other. Note that a part of the range of frequency resources set in each cell may overlap a part of the range of frequency resources set in another cell.Furthermore, the frequency resource range setting unit 504 may arrange the frequency resource ranges set for each cell on a frequency axis and adjust their order. For example, the frequency resource range setting unit 504 may arrange the frequency resource range that the first cell can use preferentially in a frequency band in which the first cell is less affected by interference from cells other than the second cell. The frequency resource range notification unit 505 notifies the DU 102 of the frequency resource range that each cell can use preferentially, arranged on the frequency axis. The frequency resource range notification unit 505 may notify the DU 102 of either the lower end or the upper end or both of the frequency resource range. Furthermore, the frequency resource range notification unit 505 may notify the DU 102 of information identifying the frequency resource range. The frequency resource range notification unit 505 can use the O1 interface or E2 interface realized by the communication circuit 405 to notify a combination of an identifier (e.g., PCI) for identifying a cell and either or both of the lower and upper ends of the range of frequency resources that the cell can preferentially use, or information specifying the range of frequency resources that the cell can preferentially use.

[0035] FIG. 6 is a diagram illustrating an example of the functional configuration of the DU 102. The DU 102 includes, as its functions, an information providing unit 601, a frequency resource range acquiring unit 602, and a radio resource allocating unit 603, for example. FIG. 6 illustrates the functional configuration of the DU 102 of this embodiment, and omits, for example, the general configuration of a DU. These functional units may be implemented, for example, by the processor 401 executing a program stored in the ROM 402 or the storage device 404 and controlling the communication circuit 405 as necessary. However, this is not limiting, and for example, dedicated hardware may be provided to implement each function. The information providing unit 601 provides the RIC 101 with information that can identify the communication volume in each cell. The information providing unit 601 can provide the RIC 101 with information that can identify the communication volume in each cell by communicating with the RIC 101 using the O1 interface or the E2 interface implemented by the communication circuit 405. The frequency resource range acquiring unit 602 acquires, from the RIC 101, a range of frequency resources that can be preferentially used by a cell associated with the DU. For example, the frequency resource range acquisition unit 602 may acquire, using the O1 interface or the E2 interface realized by the communication circuit 405, a combination of an identifier for identifying a cell (e.g., PCI) and either or both of the upper and lower ends of a range of frequency resources that the cell can preferentially use, or information specifying the range of frequency resources that the cell can preferentially use. The radio resource allocation unit 603 allocates radio resources to the UE 120 based on the range of frequency resources set for each cell. The radio resource allocation unit 603 preferentially allocates to the UE 120 radio resources (PRBs) included in the range of frequency resources that the cell to which the UE 120 is connected can preferentially use. When the radio resource allocation unit 603 acquires the lower end of the range of frequency resources set for the cell associated with the own device, the radio resource allocation unit 603 may allocate radio resources higher than the lower end, starting with the lower frequencies. When the radio resource allocation unit 603 acquires the upper end of the range of frequency resources set for the cell associated with the own device, the radio resource allocation unit 603 may allocate radio resources lower than the upper end, starting with the higher frequencies.

[0036] (Processing flow) FIG. 7 shows an example of a processing flow executed by the RIC 101 and the DU 102 in this embodiment. First, the DU 102 collects information about the communication environment in each cell (S701). For example, the DU 102 may collect setting information such as slice settings in each cell and radio resource settings based on communication quality requirements. The DU 102 may also acquire the amount of radio resources used in each cell based on information about scheduling performed by the DU 102. The DU 102 may also acquire the traffic volume of each cell based on the amount of data transmitted from the UE 120 to the network passing through the DU 102, and the amount of data transmitted from the network to the UE 120 via the DU 102. The DU 102 may also collect the amount of interference received in each cell. Then, the DU 102 provides information about the communication environment in each cell to the RIC 101 (S702). The RIC 101 executes processing based on the acquired information about the communication environment in each cell. For example, the RIC 101 may identify a first cell based on slice settings in each cell, radio resource reservation settings, and the like (S703). The RIC 101 may also select a second cell based on the amount of radio resources used in each cell and the amount of interference caused to the first cell (S704). The RIC 101 then identifies the ratio between the amounts of radio resources used in the first cell and the second cell, and sets a range of frequency resources that each cell can preferentially use based on that ratio (S705). The frequency resource ranges set for each cell are set so that at least a portion of each range is different. The RIC 101 notifies the DU 102 of the frequency resource range of each cell (S706). The RIC 101 may, for example, notify either the lower end or the upper end, or both, of the range of frequency resources that each cell can preferentially use. The DU 102 allocates radio resources to the UE 120 connected to the cell based on the range of frequency resources set for the cell provided by the RU 110 associated with the DU 102 (S707). For example, when the DU 102 acquires the lower limit of the range of frequency resources that this cell can preferentially use, the DU 102 allocates radio resources with frequencies higher than the lower limit, starting from the lowest frequency.Furthermore, for example, when the DU 102 acquires the upper end of the range of frequency resources that this cell can preferentially use, it allocates radio resources with frequencies lower than the upper end, starting from the highest frequency.

[0037] As described above, according to the present embodiment, in a RAN in which multiple cells share frequency resources, a range of frequency resources that can be used preferentially by each cell is set, and in scheduling for a UE connected to each cell, radio resources included in the range of frequency resources set for the cell to which the UE is connected are preferentially allocated. This reduces the possibility of mutual interference occurring when multiple cells simultaneously use PRBs with the same allocation on the frequency axis and the time axis in a radio frame. On the other hand, if radio resources are insufficient within the range of frequency resources set for a certain cell, interference is tolerated and radio resources outside the range of frequency resources that can be used preferentially by that cell are allocated. This makes it possible to flexibly allocate radio resources necessary for scheduling even if a predetermined range of frequency resources is set for a cell with large fluctuations in communication volume. Furthermore, in an open environment, when specific radio resources are required to be secured in a specific cell based on slice settings, etc., the specific cell and surrounding cells that have a large impact on interference with the specific cell are selected so that the sum of the radio resource usage amounts of each cell does not exceed a predetermined threshold, and the range of frequency resources that can be used preferentially by each cell is set. This reduces interference from surrounding cells against a specific cell performing communication that should be protected from interference. As described above, according to this embodiment, it is possible to improve communication quality such as RAN throughput and traffic delay, thereby contributing to the achievement of Goal 9 of the Sustainable Development Goals (SDGs) led by the United Nations, which is to "Develop resilient infrastructure, promote sustainable industrialization and foster innovation."

[0038] The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the invention. [Explanation of symbols]

[0039] 101:RIC, 102:DU, 111:RU, 112:RU, 113:RU, 114:RU, 121:UE, 122:UE, 123:UE, 124:UE, 125:UE, 126:UE, 127:UE, 128:UE

Claims

1. A control device that functions as a RAN Intelligent Controller (RIC) in an Open-Radio Access Network (O-RAN) that provides a plurality of cells sharing a predetermined range of frequency resources, An identification means for identifying a first cell included in the plurality of cells and one or more other cells surrounding the first cell included in the plurality of cells; an acquisition means for acquiring information that can identify the amount of radio resources used in each of the first cell and the other cell; a selection means for selecting one or more second cells included in the other cells such that a sum of a usage amount of radio resources in the first cell and a usage amount of radio resources in the one or more second cells does not exceed a predetermined threshold; a setting means for setting a range of frequency resources that the first cell can preferentially use and a range of frequency resources that the second cell can preferentially use, among the predetermined range of frequency resources, so that at least a part of the range is different from and a notification unit that notifies a processing device that executes allocation of radio resources in each of the first cell and the second cell of information that can identify the ranges of the frequency resources set by the setting unit. A control device characterized by:

2. The acquisition means further acquires information capable of identifying the magnitude of an influence of interference that each of the other cells has on the first cell, The selecting means selects the other cell as the second cell with a higher priority as the influence of the interference from the other cell increases.

2. The control device according to claim 1.

3. The acquiring means further acquires information capable of identifying an amount of interference in the first cell and information capable of identifying an amount of radio resources used in each of the other cells; The selecting means selects the other cell as the second cell with a higher priority as the increase in the amount of interference received by the first cell increases when the amount of radio resource usage in the other cell increases by a certain amount.

2. The control device according to claim 1.

4. The acquiring means further acquires the number of handover attempts between each of the other cells and the first cell; The selecting means selects the other cell as the second cell with a higher priority as the number of handover attempts between the other cell and the first cell increases.

2. The control device according to claim 1.

5. the acquiring means further acquires information capable of identifying a geographical location of a first base station constituting the first cell and another base station constituting the another cell; The selection means selects the second cell from among cells formed by the other base stations within a predetermined distance from the first base station.

2. The control device according to claim 1.

6. The information capable of identifying the range of frequency resources is information indicating at least one of the upper and lower ends of the range of frequency resources.

2. The control device according to claim 1.

7. The notification means notifies a Distributed Unit in the O-RAN that operates as the processing device of information capable of identifying the range of the frequency resource set by the setting means.

2. The control device according to claim 1.

8. A control method executed by a control device functioning as a RAN Intelligent Controller (RIC) in an Open-Radio Access Network (O-RAN) that provides a plurality of cells sharing a predetermined range of frequency resources, comprising: an identifying step of identifying a first cell included in the plurality of cells and one or more other cells included in the plurality of cells and surrounding the first cell; an acquisition step of acquiring information capable of identifying usage amounts of radio resources in each of the first cell and the other cell; a selection step of selecting one or more second cells included in the other cells such that a sum of a usage amount of radio resources in the first cell and a usage amount of radio resources in the one or more second cells does not exceed a predetermined threshold; a setting step of setting a range of frequency resources that the first cell can preferentially use and a range of frequency resources that the second cell can preferentially use, among the predetermined range of frequency resources, so that at least a part of the range is different from the range of frequency resources that the first cell can preferentially use; and a notification step of notifying a processing device that executes allocation of radio resources in each of the first cell and the second cell of information that can identify the ranges of the frequency resources set by the setting step. A control method comprising:

9. A computer included in a control device that functions as a RAN Intelligent Controller (RIC) in an Open-Radio Access Network (O-RAN) that provides a plurality of cells sharing a predetermined range of frequency resources, Identifying a first cell included in the plurality of cells and one or more other cells that are included in the plurality of cells and are located around the first cell; acquiring information capable of identifying usage amounts of radio resources in each of the first cell and the other cell; selecting one or more second cells included in the other cell such that a sum of a usage amount of radio resources in the first cell and a usage amount of radio resources in the one or more second cells does not exceed a predetermined threshold; Among the predetermined range of frequency resources, a range of frequency resources that the first cell can preferentially use and a range of frequency resources that the second cell can preferentially use are set so that they are at least partially different from each other; and notifying a processing device that executes allocation of radio resources in each of the first cell and the second cell of information that can identify the ranges of the set frequency resources. Program for.

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