Control device, control method, and program

Abstract

In mobile communications, the present invention provides a control device, control method, and program that monitor the status of high-traffic cells and surrounding cells, and perform pre-adjustments before surrounding cells transition to high-traffic cells. [Solution] The control device 100 includes: a congestion cell identification unit that identifies a congestion cell where communication traffic is congested from a plurality of cells including cells with different frequencies; a source cell identification unit that identifies a cell as a source cell that has the same frequency as the congestion cell and from which a plurality of user terminals located in the area are expected to move to an area covered by the congestion cell; and a handover control unit that controls the plurality of user terminals located in the source cell to facilitate handover to a cell with a different frequency than the congestion cell and the source cell.

Description

Technical Field

[0001] The present invention relates to a control device, a control method, and a program.

Background Art

[0002] Patent Document 1 describes that "a terrestrial cell using the same frequency F1 as the large zone cell 10A and a terrestrial cell of a different frequency F2 are formed in a common area such as the suburbs, and when a UE connected to the terrestrial cell of the same frequency F1 is located at the cell edge, it is preferentially handed over to the terrestrial cell of the different frequency F2 instead of the large zone cell 10A, thereby avoiding the concentration of communication traffic to the large zone cell 10A." [Prior Art Documents] [Patent Documents] [Patent Document 1] Japanese Patent Application Laid-Open No. 2022-29785

Summary of the Invention

Means for Solving the Problems

[0003] According to an embodiment of the present invention, a control device is provided. The control device may include a congestion cell specifying unit that specifies a congestion cell where communication traffic converges from a plurality of cells including cells with different frequencies. The control device may include a source cell specifying unit that specifies, as a source cell, a cell having the same frequency as the congestion cell from the plurality of cells, and in which a plurality of user terminals in the cell are predicted to move to an area covered by the congestion cell. The control device may include a handover control unit that controls so that a plurality of user terminals in the source cell are likely to hand over to a cell having a frequency different from the congestion cell and the source cell.

[0004] In the control device, the handover control unit may control the parameters related to the handover of the multiple user terminals so that the multiple user terminals located in the source cell can easily hand over to the congested cell and cells with different frequencies than the source cell. Any of the control devices may include an information acquisition unit that acquires performance information for each of the multiple cells. In any of the control devices, the congested cell identification unit may identify a cell as a congested cell if it is determined that the communication traffic is congested based on the performance information of the multiple cells.

[0005] Any of the above-mentioned control devices may include a storage unit that stores a learning model that takes performance information of a plurality of cells as input and outputs at least one of the cells among the plurality of cells that are experiencing communication traffic congestion or cells that are expected to become congested. Any of the above-mentioned control devices may include an information acquisition unit that acquires performance information for each of the plurality of cells. In any of the above-mentioned control devices, the congested cell identification unit may identify the congested cell by inputting the performance information of the plurality of cells acquired by the information acquisition unit into the learning model.

[0006] In any of the above control devices, the source cell identification unit may identify the source cell based on changes in the congestion state of past time-series communication traffic of the plurality of cells. In any of the above control devices, if the congestion cell identification unit identifies a cell covering a station as a congestion cell, the source cell identification unit may identify a cell covering a station identified based on the connection relationship between the congestion cell and the station covered by the congestion cell as the source cell.

[0007] In any of the above-mentioned control devices, the source cell identification unit may, when the congestion cell identification unit identifies a cell that covers a station as the congestion cell, identify the cell that covers the station identified based on the connection relationship between the congestion cell and the station and the timetable information as the source cell.

[0008] In any of the above-mentioned control devices, the mobile source cell identification unit may identify a cell that covers an area identified based on the connection relationship of trunk roads to the area covered by the congested cell as the mobile source cell.

[0009] In any of the above-mentioned control devices, the handover control unit may control the radio base station generating the source cell to notify idle user terminals located in the area covered by the source cell of cell reselection parameters that prioritize cells with a different frequency than the source cell.

[0010] In any of the control devices described above, the handover control unit may change parameters related to the handover of the multiple user terminals located in the source cell, depending on the status of the cell group, which includes the congested cell, the source cell, and one or more cells located between the congested cell and the source cell.

[0011] In any of the above-mentioned control devices, the handover control unit may determine a frequency that facilitates the handover of the multiple user terminals located in the source cell, depending on the status of the cell group, and control the handover-related parameters of the multiple user terminals to change them so that the multiple user terminals can be easily handed over to a cell with the determined frequency.

[0012] In any of the control devices described above, the handover control unit may determine the amount of change to the parameters related to the handover of the multiple user terminals located in the source cell, depending on the status of the cell group.

[0013] One embodiment of the present invention provides a control method performed by a computer. The control method may include a congestion cell identification step that identifies a congestion cell where communication traffic is congested from a plurality of cells including cells of different frequencies. The control method may include a source cell identification step that identifies a cell as a source cell from the plurality of cells that has the same frequency as the congestion cell and from which a plurality of user terminals located in the area are expected to move to an area covered by the congestion cell. The control method may include a handover control step that controls the plurality of user terminals located in the source cell to facilitate handover to a cell with a different frequency than the congestion cell and the source cell.

[0014] According to one embodiment of the present invention, a program is provided for causing a computer to execute any of the control methods described above.

[0015] It should be noted that the above summary of the invention does not list all the necessary features of the present invention. Furthermore, subcombinations of these features may also constitute an invention. [Brief explanation of the drawing]

[0016] [Figure 1] A schematic example of a system 10 equipped with a control device 100 is shown. [Figure 2] A schematic example of the control of wireless communication services by the control device 100 is shown below. [Figure 3] This is an explanatory diagram for describing the conventional technology. [Figure 4] An example of the state of one embodiment of the present invention is schematically shown. [Figure 5] An example of the state of one embodiment of the present invention is schematically shown. [Figure 6] An example of the state of one embodiment of the present invention is schematically shown. [Figure 7] An example of the initial state of one embodiment of the present invention is schematically shown. [Figure 8] A schematic example of the control of wireless communication services by the control device 100 is shown below. [Figure 9] It is an explanatory diagram for explaining the prior art. [Figure 10] It schematically shows an example of the state of an embodiment of the present invention. [Figure 11] It schematically shows an example of the state of an embodiment of the present invention. [Figure 12] It schematically shows an example of the state of an embodiment of the present invention. [Figure 13] It schematically shows an example of the control of the wireless communication service by the control device 100. [Figure 14] It is an explanatory diagram for explaining the prior art. [Figure 15] It schematically shows an example of the state of an embodiment of the present invention. [Figure 16] It schematically shows an example of the state of an embodiment of the present invention. [Figure 17] It schematically shows an example of the state of an embodiment of the present invention. [Figure 18] It schematically shows an example of the control of the wireless communication service by the control device 100. [Figure 19] It is an explanatory diagram for explaining the prior art. [Figure 20] It is an explanatory diagram for explaining the prior art. [Figure 21] It is an explanatory diagram for explaining the prior art. [Figure 22] It schematically shows an example of the state of an embodiment of the present invention. [Figure 23] It schematically shows an example of the state of an embodiment of the present invention. [Figure 24] It schematically shows an example of the state of an embodiment of the present invention. [Figure 25] It schematically shows an example of the control of the wireless communication service by the control device 100. [Figure 26] It schematically shows an example of the state of an embodiment of the present invention. [Figure 27] It schematically shows an example of the control of the wireless communication service by the control device 100. [Figure 28]A schematic example of the control of wireless communication services by the control device 100 is shown below. [Figure 29] An example of the state of one embodiment of the present invention is schematically shown. [Figure 30] An example of the functional configuration of the control device 100 is schematically shown. [Figure 31] An example of the processing flow by the control device 100 is schematically shown. [Figure 32] A schematic example of the hardware configuration of a computer 1200 that functions as a control device 100 is shown below. [Modes for carrying out the invention]

[0017] The present invention will be described below through embodiments of the invention, but these embodiments are not intended to limit the invention as defined in the claims. Furthermore, not all combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0018] In mobile communications, when a terminal hands over between different frequencies, the communication switching time for the terminal tends to be long. Therefore, mobility settings are often configured to facilitate handovers within the same frequency. As a result, current mobility settings in mobile communications tend to cause user terminals to continue using a certain frequency once they are in the area. Consequently, certain frequencies tend to become congested, especially in high-traffic cells where user terminals are concentrated, such as at stations and on railway lines.

[0019] The control device 100 according to this embodiment has a configuration that contributes to solving these problems. For example, the control device 100 monitors the status of high-traffic cells and surrounding cells, and performs pre-adjustments before surrounding cells transition to high-traffic cells. Specifically, for example, it switches the target cells for handover and cell reselection of user terminals in surrounding cells to cells other than those on frequencies where congestion has occurred, distributing them to other frequencies before they are in the high-traffic cell. Furthermore, it performs pre-adjustments on a prediction basis by using AI (Artificial Intelligence) / ML (Machine Learning).

[0020] Figure 1 schematically shows an example of a system 10 equipped with a control device 100. In the example shown in Figure 1, the system 10 includes a network 90. ​​In the example shown in Figure 1, the system 10 includes a plurality of wireless base stations 200.

[0021] The control device 100 may be connected to the network 90. ​​Multiple radio base stations 200 may be connected to the network 90. ​​The control device 100 may be connected to each of the multiple radio base stations 200 in a communicative manner. In the example shown in Figure 1, the control device 100 is connected to each of the multiple radio base stations 200 in a communicative manner via the network 90. ​​Each of the multiple radio base stations 200 may form a cell 20.

[0022] System 10 may provide wireless communication services. Network 90 may constitute a RAN (Radio Access Network). The control device 100 may be located in the operation section of the RAN. Network 90 may include a core network. In this case, the control device 100 may be located in the core network. Alternatively, for example, an information processing infrastructure may be connected below the core network, and a wireless base station 200 may be connected below the information processing infrastructure. In this case, the control device 100 may be connected to the information processing infrastructure. The control device 100 may be located in the information processing infrastructure.

[0023] System 10 as a whole may constitute a RAN (Radio Access Network). Network 90 may be a core network. In this case, system 10 may constitute a RAN with radio base stations 200 located below the core network. In this case, for example, an information processing infrastructure may be connected below the core network, and the radio base stations 200 may be connected below the information processing infrastructure. In this case, the control device 100 may be connected to the information processing infrastructure. The control device 100 may be located on the information processing infrastructure.

[0024] The RAN (Range Area Network) comprised of system 10 may include multiple frequencies that are different from each other. User 80 may receive wireless communication services using user terminal 82.

[0025] The control device 100 may control the wireless communication services provided by the system 10. For example, the control device 100 controls the handover of the user terminal 82. For example, the control device 100 controls the cell reselection of the user terminal 82. In the example shown in Figure 1, the control device 100 controls the user terminal 82 located in a cell 20 formed by multiple wireless base stations 200 via the network 90 and the multiple wireless base stations 200.

[0026] In the example above, there may be multiple information processing infrastructures. The information processing infrastructures may be installed in corresponding regions. The regions may be, for example, regions of a similar size to each prefecture of Japan. The regions may be, for example, regions of a smaller size than each prefecture of Japan. The regions may be, for example, regions of a larger size than each prefecture of Japan.

[0027] In the example above, the information processing infrastructure may have multiple layers. For example, the upper layer of the information processing infrastructure may be called the management infrastructure, and the lower layer may be called the distributed infrastructure. The management infrastructure may be called the Core Brain, and the distributed infrastructure may be called the Regional Brain. For example, if two layers of distributed infrastructure are placed below the management infrastructure, the management infrastructure may be called the Core Brain, the distributed infrastructure at the layer below it may be called the Regional Brain, and the distributed infrastructure at the layer below that may be called the Sub-Regional Brain.

[0028] The information processing infrastructure may have one or more CPUs (Central Processing Units). The information processing infrastructure may have one or more GPUs (Graphics Processing Units). The information processing infrastructure may have multiple superchips, each connected to a CPU and a GPU by an interconnect. This interconnect may be memory consistent and capable of achieving high bandwidth and low latency. Thus, the information processing infrastructure may have both CPU resources and GPU resources as computing resources.

[0029] Figure 2 schematically shows an example of control of a wireless communication service by the control device 100. In the example shown in Figure 2, a train 40 carrying multiple users 80 each carrying a user terminal 82 is located at station 42. The train 40 departs from station 42, travels along the tracks 44, and arrives at station 43, completing a section 45.

[0030] In this example, section 45 is covered by multiple cells, including cells with different frequencies. In the example shown in Figure 2, section 45 is covered by four cells 20 at frequency A, three cells 20 at frequency B, and two cells 20 at frequency C. In the example shown in Figure 2, the communication traffic of the frequency A cell 20 covering station 43 is congested, and accepting a handover from another cell 20 would further worsen the congestion.

[0031] Figure 3 is an explanatory diagram for explaining the prior art. Figure 3 shows the state after train 40 has moved from the state shown in Figure 2, traveled along the tracks 44, and arrived at station 43.

[0032] As mentioned above, in conventional mobile communication control, once a user terminal 82 is present on a certain frequency, it tends to continue using that frequency afterward. Therefore, the user terminal 82 inside the train 40 tends to continue using frequency A, which it was present on at station 42, on the tracks 44 and at station 43.

[0033] Therefore, as shown in the example in Figure 3, if no measures are taken, the user terminal 82 of train 40, which was located in cell 20 of frequency A in Figure 2, will hand over to cell 20 of frequency A as train 40 moves along track 44, and when it arrives at station 43, it will hand over to cell 20 of frequency A that covers station 43, which is already congested, as shown in Figure 3. As a result, the communication of user terminals located in the already congested cell 20 will worsen, and the communication of the user terminal 82 of train 40 will also worsen.

[0034] Next, as an embodiment of the present invention, an embodiment in which the state transitions in the order of Figure 4, Figure 5, and Figure 6 will be described, with Figure 2 being the starting state. In Figure 2, the control device 100 identifies a congested cell where communication traffic is congested from among a plurality of cells 20, including cells 20 with different frequencies. For example, from the four cells 20 with frequency A, the three cells 20 with frequency B, and the two cells 20 with frequency C shown in Figure 2, the control device 100 identifies the cell 20 with frequency A that covers station 43 as a congested cell.

[0035] The following describes a specific example of how the control device 100 identifies a congested cell. This example is merely illustrative, and the method by which the control device 100 identifies a congested cell may be other than that described herein.

[0036] The control device 100 may acquire performance information for each of the multiple cells 20. For example, the control device 100 may acquire information on the number of connected users and / or downlink throughput for each of the four cells 20 at frequency A, the three cells 20 at frequency B, and the two cells 20 at frequency C, as shown in Figure 2. The information on the number of connected users may be the number of RRC_CU (Radio Resource Control_Connected Users). The information on downlink throughput may be DL (Downlink) User throughput.

[0037] The control device 100 may identify a cell 20 as a congested cell if it determines that the communication traffic is congested based on the performance information of multiple cells 20. For example, the control device 100 may determine that a cell 20 is congested if the number of connected users of that cell 20 is greater than a predetermined threshold.

[0038] For example, the control device 100 may determine that cell 20 is congested if the downlink throughput of cell 20 is less than a predetermined threshold. For example, the control device 100 may determine that cell 20 is congested if the number of connected users of cell 20 is greater than a predetermined threshold AND the downlink throughput is less than a predetermined threshold.

[0039] The control device 100 may store a learning model that takes performance information of multiple cells 20 as input and outputs at least one of the cells 20 that are experiencing communication traffic congestion or cells 20 that are expected to become congested. The control device 100 may identify congested cells by inputting the acquired performance information of multiple cells 20 into the learning model.

[0040] The control device 100 identifies a cell 20 from among multiple cells 20 that has the same frequency as a congested cell and is expected to move to an area covered by the congested cell, as the source cell. For example, from the four cells 20 with frequency A, three cells 20 with frequency B, and two cells 20 with frequency C shown in Figure 2, the control device 100 identifies a cell 20 with frequency A that covers station 42 as the source cell.

[0041] The following describes a specific example of how the control device 100 identifies the source cell. This example is merely illustrative, and the method by which the control device 100 identifies the source cell may be other than that described herein.

[0042] The control device 100 may identify the source cell based on changes in the congestion state of past time-series communication traffic of multiple cells 20. For example, since public transportation such as trains and buses have predetermined routes, when a crowded public transportation vehicle moves along that route, a large number of user terminals 82 will move along that route together.

[0043] In this case, since the congestion state of the communication traffic changes over time along the travel route, multiple adjacent cells 20 of the same frequency will become congested sequentially over time. For example, the control device 100 may use this sequential order to identify the source cell.

[0044] When a cell 20 covering a station is identified as a congested cell, the control device 100 may identify a cell 20 covering a station identified based on the connection relationship with the station covered by the congested cell as the source cell.

[0045] In the example shown in Figure 2, stations 42 and 43 are adjacent. For example, when the control device 100 identifies a cell 20 of frequency A covering station 43 as a congested cell, it identifies station 42, which is adjacent to the congested cell station 43, and identifies the cell 20 of frequency A covering station 42 as the source cell.

[0046] Here, the control device 100 has been described using the example of identifying one station adjacent to the station covered by the congested cell and identifying the cell 20 covering that station as the source cell, but it is not limited to this. For example, the control device 100 may identify two or more stations adjacent to the congested station and identify the cell 20 covering those stations as the source cell. For example, the control device 100 may identify each of the multiple stations connected to the station covered by the congested cell and identify each of the multiple cells 20 covering each of those multiple stations as the source cell.

[0047] In the example shown in Figure 2, the cell 20 covering a station identified based on the connection relationship with the station covered by the congestion cell was identified as the source cell. However, the source cell does not have to be the cell 20 covering a station. For example, the control device 100 identifies the cell 20 covering the train 40 on the track 44, which was identified based on the connection relationship with the station covered by the congestion cell and the distance from the station covered by the congestion cell, as the source cell.

[0048] For example, the control device 100 identifies cells 20 that cover trains 40 whose distance from the station covered by the congestion cell is below a predetermined threshold, from among multiple trains 40 on the track 44 connected to the station covered by the congestion cell. For example, the control device 100 obtains the communication KPI (Key Performance Indicators) of each of the multiple cells 20 that cover the track 44 connected to the station covered by the congestion cell and whose distance from the station covered by the congestion cell is below the said threshold, and identifies the cell 20 whose communication KPI value satisfies predetermined conditions as the source cell.

[0049] For example, in cases where the distance between adjacent stations is relatively large, such as on express lines like Shinkansen or local lines, it may be preferable from the standpoint of processing load and congestion estimation to identify the source cell not when the train 40 enters the cell 20 covering the adjacent station, but when the train 40 has departed the adjacent station and is approaching a station covered by a congested cell. The above configuration is expected to be effective in such cases.

[0050] When a cell 20 covering a station is identified as a congested cell, the control device 100 may identify a cell 20 covering a station identified based on the connection relationship with the station covered by the congested cell and timetable information as the source cell. In particular, in countries and regions where the on-time operation of public transportation is considered important and is actually achieved, using timetable information in addition to the station connection relationship makes it possible to identify what type of train or other vehicle will arrive at the station covered by the congested cell and at what time, thus making it possible to identify the source cell more accurately.

[0051] The control device 100 may identify cells as source cells that are expected to move to an area covered by a congested cell, based on calendar information including the date and time. For example, certain stations may become congested during specific times in the morning and evening on weekdays due to the large number of public transport users commuting to work or school. The control device 100 may identify multiple cells 20 that cover the vicinity of such a congested station as source cells, but only during specific times in the morning and evening on weekdays. The control device 100 may also identify the cells 20 that cover the congested station as source cells. This allows for, for example, clearing the congested frequencies of congested stations in advance during peak hours, thereby suppressing the occurrence of congestion.

[0052] The control device 100 controls multiple user terminals 82 located in the source cell to facilitate handover to a cell 20 with a different frequency than the congested cell and the source cell. For example, the control device 100 controls user terminals 82 in a train 40 located at station 42 in Figure 2 to facilitate handover to a cell with a different frequency B or frequency C than frequency A.

[0053] The following describes a specific example of how the control device 100 controls the handover of the user terminal 82. This example is merely illustrative, and the control of the handover of the user terminal 82 by the control device 100 may be carried out by methods other than those described herein.

[0054] The control device 100 may control the multiple user terminals 82 to modify parameters related to handover in order to facilitate handover to a cell with a different frequency than the congested cell and the source cell. For example, the control device 100 may control the multiple user terminals 82 located in the source cell to modify the threshold of the event trigger that sends a measurement report, or to modify the offset value.

[0055] The user terminal 82 may perform a measurement report based on a measurement configuration specified in advance by the wireless base station 200. The user terminal 82 may transmit a measurement report to the wireless base station 200 if the measurement result satisfies the conditions indicated in the measurement configuration. The measurement configuration includes, for example, information indicating the frequency of the target to be measured, information indicating the cell of the target to be measured, information indicating the beam of the target to be measured, the measurement period, and the threshold of the event trigger for transmitting the measurement report.

[0056] The wireless base station 200 may determine whether or not to hand over the user terminal 82 based on the received measurement report. Specifically, for example, the wireless base station 200 may determine whether or not to hand over based on the measured values ​​such as RSRP (Reference Signal Received Power), RSRQ (Reference Signal Received Quality), and SINR (Signal-to-Interference-plus-Noise Ratio) included in the measurement report.

[0057] Therefore, by controlling the control device 100 to change the threshold of the event trigger that sends a measurement report to multiple user terminals 82 located in the source cell, or to change the offset value, the opportunities for the wireless base station 200 to receive a measurement report from the user terminals 82 increase.

[0058] In addition, the control device 100 may change the threshold for determining whether or not the wireless base station 200 will hand over the user terminal 82. Specifically, the control device 100 changes the threshold for at least one of the wireless base stations 200 of the source cell and the wireless base station 200 of the handover destination cell. As a result, the opportunities for the wireless base station 200 to determine whether or not to hand over the user terminal 82 increase, making it easier for the user terminal 82 to be handed over. Hereafter, this situation may be referred to as "making it easier to hand over".

[0059] For example, if the event trigger is an A3 trigger, the control device 100 changes the offset values ​​between the serving cell and the neighbor cell to be smaller. For example, the control device 100 changes the offset value of RSRP to be smaller. For example, the control device 100 changes the offset value of RSRQ to be smaller. This makes it easier for the A3 trigger to be activated even if the amount by which the neighbor cell's RSRP etc. exceeds the serving cell's RSRP etc. is small, and makes it easier for the user terminal 82 to send a measurement report.

[0060] In addition to changing the offset value, the control device 100 may also change the hysteresis value to be smaller. This reduces the delay between when the trigger condition for the offset value is met and when the handover actually occurs, making the handover easier.

[0061] For example, if the event trigger is an A5 trigger, the control device 100 changes the RSRP threshold value from the serving cell to an increased value. The control device 100 may also change the RSRP threshold value from the neighbor cell to an decreased value. The control device 100 may change the RSRP threshold value of the serving cell to an increased value and the RSRP threshold value of the neighbor cell to an decreased value. This makes it easier for the user terminal 82 to send a measurement report.

[0062] The control device 100 may change the threshold value of the RSRQ from the serving cell to be higher. The control device 100 may change the threshold value of the RSRQ from the neighbor cell to be lower. The control device 100 may change the threshold value of the RSRQ from the serving cell to be higher and the threshold value of the RSRQ from the neighbor cell to be lower. This makes it easier for the user terminal 82 to send a measurement report.

[0063] In addition to changing the threshold value, the control device 100 may also change the hysteresis value to be smaller. This reduces the delay between when the offset trigger condition is met and when the handover actually occurs, making the handover easier.

[0064] The control device 100 may change the levels of RSRP, etc., of multiple cells 20. For example, 100 may change the value of CIO (Cell Individual Offset). For example, the control device 100 may increase the CIO value of cells 20 with different frequencies from the congested cell and the source cell among the multiple cells 20. For example, the control device 100 may decrease the CIO value of cells 20 with the same frequency as the congested cell and the source cell among the multiple cells 20. This makes it easier for the user terminal 82 to send a measurement report.

[0065] For example, if the event trigger is an A1 trigger, the control device 100 changes the threshold value of the A1 trigger to a smaller value. For example, the control device 100 changes the threshold value of the RSRP to a smaller value. For example, the control device 100 changes the threshold value of the RSRQ to a smaller value. This makes it easier for RSRP and other signals from the serving cell to exceed the threshold, making it easier for the user terminal 82 to send a measurement report.

[0066] For example, if the event trigger is an A2 trigger, the control device 100 changes the threshold value of the A2 trigger to be higher. For example, the control device 100 changes the threshold value of the RSRP to be higher. For example, the control device 100 changes the threshold value of the RSRQ to be higher. This makes it easier for RSRP etc. from the serving cell to fall below the threshold, making it easier for the user terminal 82 to send a measurement report.

[0067] For example, if the event trigger is an A4 trigger, the control device 100 changes the threshold value of the A4 trigger to a smaller value. For example, the control device 100 changes the threshold value of the RSRP to a smaller value. For example, the control device 100 changes the threshold value of the RSRQ to a smaller value. This makes it easier for RSRP and other signals from neighbor cells to exceed the threshold, making it easier for the user terminal 82 to send a measurement report.

[0068] By the control device 100 making the above-described changes to the handover-related parameters for the user terminal 82, the user terminal 82 is able to more easily transmit a measurement report to the wireless base station 200 when the user terminal 82 is located further away from the neighbor cell on the same frequency as the serving cell of the user terminal 82, compared to when nothing is done.

[0069] Since cells 20 operating on the same frequency are arranged so that their coverage areas do not overlap as much as possible, when the user terminal 82 is in such a position, the signal strength received from neighbor cells of the same frequency may be weaker. Therefore, the signal strength received from neighbor cells of different frequencies may be relatively stronger. As a result, the user terminal 82 is more likely to hand over to a cell of a different frequency than the congested cell and the source cell.

[0070] The control device 100 may control the event triggers of multiple user terminals 82 to change them so that it is easier to hand over to a cell with a different frequency than the congested cell and the source cell. For example, if the event trigger is "detection of a cell 20 other than the serving cell that has a higher radio wave reception strength than the serving cell at the same frequency as the serving cell", the control device 100 may remove the condition "at the same frequency as the serving cell" and change the event trigger to "detection of a cell 20 other than the serving cell that has a higher radio wave reception strength than the serving cell". Alternatively, the control device 100 may change the condition "at the same frequency as the serving cell" and change the event trigger to "detection of a cell 20 other than the serving cell that has a higher radio wave reception strength than the serving cell at a different frequency than the serving cell".

[0071] The control device 100 may instruct multiple user terminals 82 to specify the handover destination cell 20 in order to facilitate handover to a cell with a different frequency than the congested cell and the source cell.

[0072] In the area covered by the source cell, there may also be user terminals 82 that are idle and not located within the source cell's area. If such user terminals 82 subsequently become located within the area by selecting a cell with the same frequency as the congested cell and the source cell during cell reselection, the same frequency cell 20 may be selected during subsequent handovers, potentially worsening the congestion in the congested cell.

[0073] The control device 100 may control the radio base station 200 that is generating the source cell to notify idle user terminals 82 located in the area covered by the source cell of cell selection parameters that prioritize cells with a different frequency than the source cell. This can suppress the worsening of congestion caused by idle user terminals 82 subsequently becoming located in congested cells and cells with the same frequency as the source cell.

[0074] The following describes a specific example of how the control device 100 controls cell reselection of the user terminal 82. This example is merely illustrative, and the control device 100 may control cell reselection of the user terminal 82 in ways other than those described herein.

[0075] For example, the control device 100 may control the radio base station 200 to change the threshold value for re-selecting a cell of the same frequency as the cell in which the user terminal 82 was located immediately before it became idle. For example, the control device 100 may control the radio base station 200 to send a notification to reduce the value of sIntraSearchP. This makes it less likely for the value of sIntraSearchP to fall below the threshold, making it less likely for the user terminal 82 to start searching for a cell 20 of the same frequency.

[0076] For example, the control device 100 may control the radio base station 200 to change the threshold value for re-selecting a cell with a different frequency than the cell in which the user terminal 82 was located immediately before it became idle. For example, the control device 100 may control the radio base station 200 to notify it to increase the value of sNonIntraSearchP. This makes it easier for the value of sNonIntraSearchP to fall below the threshold, making it easier for the user terminal 82 to start searching for a cell 20 with a different frequency.

[0077] For example, the control device 100 may control the radio base station 200 to change a parameter indicating the priority of cell reselection. For example, the control device 100 may control the radio base station 200 to notify it to reselect a cell with a different frequency than the congested cell and the source cell, prioritizing their selection. For example, the control device 100 may control the radio base station 200 to notify it to reselect a cell with a lower priority than the congested cell and the source cell.

[0078] For example, the control device 100 may be modified to reduce the hysteresis value. For example, the control device 100 may be modified to reduce the value of qHyst.

[0079] In the example shown in Figure 2, the user terminals 82 inside the train 40 are controlled by the control device 100 to facilitate handover to frequency B or frequency C. Therefore, when the train 40 departs from station 42 and transitions to the state shown in Figure 4, some or all of the user terminals 82 inside the train 40 that are located in a cell of frequency A will hand over to a cell 20 of frequency B or frequency C, rather than to frequency A. In the example shown in Figure 4, some of the user terminals 82 inside the train 40 that are located in a cell of frequency A will hand over to a cell of frequency B.

[0080] Next, when train 40 moves further from the state shown in Figure 4 and transitions to the state shown in Figure 5, some or all of the user terminals 82 within train 40 that are located in a cell with frequency A will be handed over to a cell with frequency B or frequency C, rather than to a cell with frequency A. In the example shown in Figure 4, some of the user terminals 82 within train 40 that are located in a cell with frequency A will be handed over to a cell with frequency C.

[0081] Next, when train 40 moves further from the state shown in Figure 5 and arrives at station 43, transitioning to the state shown in Figure 6, some or all of the user terminals 82 within train 40 that are located in a cell with frequency A will be handed over to a cell 20 with frequency B or frequency C, rather than a cell with frequency A. In the example shown in Figure 6, some of the user terminals 82 within train 40 that are located in a cell with frequency A will be handed over to a cell with frequency C. In this case, in the state shown in Figure 2 when train 40 was located at station 42, many of the user terminals 82 within train 40 that were located in a cell with frequency A will be handed over to a cell with frequency other than A by the time train 40 arrives at station 43, as shown in Figure 6, thus suppressing the worsening of congestion in congested cells.

[0082] Figure 7 schematically shows an example of the starting state in one embodiment of the present invention. In the embodiment described above, where Figure 2 is the starting state and the states transition in the order of Figures 4, 5, and 6, the starting state may be the state in Figure 7 instead of the state in Figure 2.

[0083] Figure 7 primarily explains the differences from Figure 2. In the example shown in Figure 7, not only is the cell 20 of frequency A covering station 43, which is a congested cell, congested, but the cell 20 of frequency A covering station 42, which is the source cell, is also congested. Thus, it is possible that the source cell is also congested. Even in such cases, by performing the same control as in the embodiment described above, where Figure 2 is the starting state and the states transition in the order of Figures 4, 5, and 6, the deterioration of congestion in the congested cell can be suppressed.

[0084] Figure 8 schematically shows an example of control of a wireless communication service by the control device 100. The example shown in Figure 8 will mainly be explained in terms of differences from the example shown in Figure 2. In the example shown in Figure 8, multiple trains, train 40 and train 41, move along section 45. In the state shown in Figure 8, there are currently no congested cells 20. However, in the near future, it is expected that cell 20 covering frequency A, which covers station 43, will become congested when user terminals 82 in train 40 and user terminals 82 in train 41 hand over to a cell covering frequency A that covers station 43.

[0085] Figure 9 is an explanatory diagram for explaining the prior art. Figure 9 shows the state after trains 40 and 41 have moved from the state shown in Figure 8, traveled along track 44, and arrived at station 43.

[0086] As mentioned above, in conventional mobile communication control, once a user terminal 82 is present on a certain frequency, it tends to continue using that frequency afterward. Therefore, user terminals 82 inside train 40 and train 41 tend to continue using frequency A, which they have previously been present on, on the tracks 44 and at stations 43.

[0087] Therefore, as shown in the example in Figure 9, if no measures are taken, the user terminals 82 in train 40 and train 41, which were located in cell 20 of frequency A in Figure 8, will hand over to cell 20 of frequency A as trains 40 and 41 travel along track 44. When they arrive at station 43, as shown in Figure 9, they will hand over to cell 20 of frequency A that covers station 43, causing congestion.

[0088] Next, as an embodiment of the present invention, we will describe an embodiment in which the state transitions in the order of Figure 10, Figure 11, and Figure 12, with Figure 8 being the starting state.

[0089] In Figure 8, the control device 100 may identify a congested cell where communication traffic is congested from among multiple cells, including cells with different frequencies. For example, from the four cells 20 with frequency A, the three cells 20 with frequency B, and the two cells 20 with frequency C shown in Figure 8, the control device 100 identifies the cell 20 with frequency A that covers station 43 as a congested cell, as it is expected to become congested in the near future.

[0090] The control device 100 may identify a cell 20 that it has determined will experience communication traffic congestion based on the performance information of multiple cells 20 as a congested cell. For example, the control device 100 may determine that a cell 20 will experience congestion in the future by processing the performance information of multiple cells 20. For example, in the example shown in Figure 8, the control device 100 may determine that station 43 will experience congestion in the near future by adding up the number of connected users of each of the multiple frequency A cells 20 covering section 45. The control device 100 may also identify congested cells by inputting the acquired performance information of multiple cells into a learning model.

[0091] The control device 100 may identify a cell 20 with the same frequency as a congestion cell, from among multiple cells, as the source cell, where multiple user terminals located in the area are expected to move to an area covered by the congestion cell. For example, from the four cells 20 with frequency A, three cells 20 with frequency B, and two cells 20 with frequency C shown in Figure 8, the control device 100 identifies the cell 20 with frequency A that covers station 42 as the source cell. The control device 100 may also identify the cell 20 with frequency A that covers the area where the train 41 on the tracks 44 is located as the source cell.

[0092] The control device 100 may identify multiple source cells. For example, the control device 100 may identify a cell 20 with frequency A that covers station 42 and another cell 20 with frequency A that covers the area where the train 41 on track 44 is located as source cells.

[0093] Here, we will describe the case where the control device 100 identifies cell 20 of frequency A, which covers station 42, as the source cell. The control device 100 may control multiple user terminals 82 located in the source cell to facilitate handover to a cell with a different frequency than the congested cell and the source cell. For example, the control device 100 may control user terminals 82 in train 40 located at station 42 in Figure 8 to facilitate handover to a cell with a different frequency than frequency A, such as cell B or frequency C. The control device 100 may control parameters related to the handover of multiple user terminals to facilitate handover to a cell with a different frequency than the congested cell and the source cell, similar to the embodiment in which Figure 2 is the starting state and the states transition in the order of Figures 4, 5, and 6.

[0094] In the example shown in Figure 8, the user terminals 82 inside the train 40 are controlled by the control device 100 to facilitate handover to frequency B or frequency C. Therefore, when the train 40 departs from station 42 and transitions to the state shown in Figure 10, some or all of the user terminals 82 inside the train 40 that are in a cell with frequency A will hand over to a cell 20 with frequency B or frequency C, rather than frequency A. In the example shown in Figure 10, some of the user terminals 82 inside the train 40 that are in a cell with frequency A will hand over to a cell with frequency B.

[0095] Next, when train 40 moves further from the state shown in Figure 10 and transitions to the state shown in Figure 11, some or all of the user terminals 82 within train 40 that are located in a cell with frequency A will be handed over to a cell with frequency B or frequency C, rather than to a cell with frequency A. In the example shown in Figure 11, some of the user terminals 82 within train 40 that are located in a cell with frequency A will be handed over to a cell with frequency C.

[0096] Next, when train 40 moves further from the state shown in Figure 11 and arrives at station 43, transitioning to the state shown in Figure 12, some or all of the user terminals 82 within train 40 that are located in a cell with frequency A will be handed over to a cell 20 with frequency B or frequency C, rather than a cell with frequency A. In the example shown in Figure 12, some of the user terminals 82 within train 40 that are located in a cell with frequency A will be handed over to a cell with frequency C. In this case, in the state shown in Figure 8 when train 40 was located at station 42, many of the user terminals 82 within train 40 that were located in a cell with frequency A will be handed over to a cell with frequency other than A by the time train 40 arrives at station 43 in the state shown in Figure 12, thus preventing congestion in the cell with frequency A that covers station 43.

[0097] In the example shown in Figure 8, even if the control device 100 identifies a cell 20 of frequency A that covers the area where the train 41 on the track 44 is located, rather than a cell 20 of frequency A that covers station 42, as the source cell, the control device 100 may perform the same control. Furthermore, it will be understood by those skilled in the art that this can suppress congestion of the cell of frequency A that covers station 43.

[0098] The control device 100 may identify multiple source cells. The control device 100 may prioritize handing over user terminals 82 located in more congested source cells to congested cells and cells with different frequencies than the source cells. For example, the control device 100 may acquire performance information from multiple source cells and, based on the acquired performance information, decide which source cell's user terminal 82 to prioritize control over. For example, the control device 100 may decide to prioritize control over source cells whose performance values ​​included in the performance information are above a predetermined threshold. The control device 100 may also prioritize handing over all of the identified source cells to congested cells and cells with different frequencies than the source cells.

[0099] In the example shown in Figure 8, even if the control device 100 identifies multiple source cells and identifies the cell 20 of frequency A covering station 42 and the cell 20 of frequency A covering the area where the train 41 on the tracks 44 is located as source cells, it will be understood by those skilled in the art that the control device 100 may perform similar control for each of the multiple source cells. By the control device 100 identifying multiple source cells and performing control on user terminals 82 located in multiple source cells, congestion of the cell of frequency A covering station 43 can be further suppressed.

[0100] Figure 13 schematically shows an example of control of a wireless communication service by the control device 100. In the example shown in Figure 13, multiple vehicles carrying users 80 each carrying a user terminal 82 travel along a road 54. In the example shown in Figure 13, these multiple vehicles travel along a section 55 on the road 54 to reach a traffic service facility 53.

[0101] In this example, section 55 is covered by multiple cells, including cells with different frequencies. In the example shown in Figure 13, section 55 is covered by four cells 20 at frequency A, three cells 20 at frequency B, and two cells 20 at frequency C. In the example shown in Figure 13, the communication traffic of the frequency A cell 20 covering the transportation service facility 53 is congested, and accepting handovers from other cells 20 would further worsen the congestion.

[0102] In this example, road 54 may be a relatively large road. For example, road 54 may be a main road. For example, road 54 may be an expressway (national highway). In this case, the traffic service facility 53 may be, for example, a service area, a parking area, etc.

[0103] For example, road 54 may be a national highway. For example, road 54 may be a prefectural road. In this case, the traffic service facility 53 may be, for example, a roadside rest area.

[0104] In this example, we illustrate a situation where the communication traffic of cell 20 on frequency A covering the transportation service facility 53 is currently congested, but this is not the only example. For example, in the near future, if it is expected that multiple vehicles will move to the transportation service facility 53 and multiple user terminals 82 in multiple vehicles will hand over to the cell on frequency A covering the transportation service facility 53, causing congestion in cell 20 on frequency A covering the transportation service facility 53, the same considerations can be applied.

[0105] In this example, a state of congestion in the communication traffic of cell 20 on frequency A, which covers the transportation service facility 53, is illustrated. However, the congested cell 20 does not necessarily have to cover the transportation service facility 53. For example, the congested cell 20 may be a cell 20 that covers the area where the event venue is located. For example, in the example shown in Figure 13, the event venue may be located at the same location as the transportation service facility 53.

[0106] In this example, a state of congestion in the communication traffic of cell 20 of frequency A covering the traffic service facility 53 is illustrated, but the congested cell 20 does not necessarily have to cover a specific facility. For example, the congested cell 20 may be a cell 20 that covers an area where traffic congestion is occurring. For example, in the example shown in Figure 13, instead of the traffic service facility 53, an area where congestion is occurring due to multiple vehicles may be located at the location of the traffic service facility 53.

[0107] In this example, the multiple vehicles may be automobiles. The size and classification of the multiple vehicles are not particularly limited. For example, the multiple vehicles may be passenger cars, trucks, buses and other commercial vehicles. In the example shown in Figure 13, vehicle 50 is a bus, and vehicles 51 and 52 are passenger cars. In the examples shown in Figures 13 to 17, for simplicity, the movement of vehicles 50, 51, and 52 among the multiple vehicles will be used as an example for explanation.

[0108] Figure 14 is an explanatory diagram for explaining the prior art. Figure 14 shows the state after vehicles 50, 51, and 52 have moved from the state shown in Figure 13, traveled along road 54, and arrived at the traffic service facility 53.

[0109] As mentioned above, in conventional mobile communication control, once a user terminal 82 is present on a certain frequency, it tends to continue using that frequency afterward. Therefore, multiple user terminals 82 in multiple vehicles tend to continue using frequency A, once they have been present on it, on roads 54 and traffic service facilities 53.

[0110] Therefore, as shown in the example in Figure 14, if no measures are taken, the user terminals 82 in vehicle 50, vehicle 51, and vehicle 52, which were each located in cell 20 of frequency A in Figure 13, will hand over to cell 20 of frequency A as vehicles 50, 51, and 52 move along road 54, and when they arrive at the traffic service facility 53, they will hand over to cell 20 of frequency A that covers the traffic service facility 53, as shown in Figure 14. As a result, communication for user terminals already located in cell 20 that is congested will worsen, and communication for user terminals 82 in vehicles 50, 51, and 52 will also worsen.

[0111] Next, as an embodiment of the present invention, we will describe an embodiment in which the state transitions in the order of Figure 15, Figure 16, and Figure 17, with Figure 13 being the starting state.

[0112] In Figure 13, the control device 100 may identify a congested cell where communication traffic is congested from among multiple cells, including cells with different frequencies. For example, from the four cells 20 of frequency A, the three cells 20 of frequency B, and the two cells 20 of frequency C shown in Figure 13, the control device 100 identifies the cell 20 of frequency A that covers the transportation service facility 53 as a congested cell. As mentioned above, the control device 100 may also identify the cell 20 of frequency A that covers the transportation service facility 53 as a congested cell because it is expected to become congested in the near future.

[0113] The control device 100 may identify a cell 20 that it has determined is experiencing communication traffic congestion based on the performance information of multiple cells 20 as a congested cell, as in the examples shown in Figures 8 to 12.

[0114] The control device 100 may identify a cell 20 with the same frequency as a congestion cell as a source cell from among multiple cells, where it is predicted that multiple user terminals 82 located in the area will move to an area covered by the congestion cell. For example, from the four cells 20 with frequency A, the three cells 20 with frequency B, and the two cells 20 with frequency C shown in Figure 13, the control device 100 identifies at least one of the following as a source cell: a cell 20 with frequency A covering the area where vehicle 50 is traveling, a cell 20 with frequency A covering the area where vehicle 51 is traveling, and a cell 20 with frequency A covering the area where vehicle 52 is traveling.

[0115] The control device 100 may identify a cell covering an area determined based on the connectivity of trunk roads to the area covered by the congestion cell as the source cell. For example, in Figure 13, since road 54 is connected to traffic service facility 53, the control device 100 may identify at least one of the three frequency A cells 20 covering road 54 as the source cell based on this connectivity.

[0116] Here, we will describe the case where the control device 100 identifies all three cells 20 of frequency A that cover road 54 as source cells.

[0117] The control device 100 may control multiple user terminals 82 located in the source cell to facilitate handover to a cell with a different frequency than the congested cell and the source cell. For example, the control device 100 controls user terminals 82 located in vehicles 50, 51, and 52, which are located in three cells 20 of frequency A covering the road 54 in Figure 13, to facilitate handover to a cell with a different frequency B or C. The control device 100 may also control parameters related to the handover of multiple user terminals to facilitate handover to a cell with a different frequency than the congested cell and the source cell, similar to the embodiment in which Figure 2 is the starting state and the states transition in the order of Figures 4, 5, and 6.

[0118] In the example shown in Figure 13, the user terminals 82 inside vehicles 50, 51, and 52 are controlled by the control device 100 to facilitate handover to frequency B or frequency C. Therefore, when vehicles 50, 51, and 52 move along road 54 and transition to the state shown in Figure 15, some or all of the user terminals 82 inside vehicles 50, 51, and 52, which are located in a cell of frequency A, will hand over to a cell 20 of frequency B or frequency C, rather than to a cell of frequency A.

[0119] In the example shown in Figure 15, some of the user terminals 82 in vehicle 50 located in cell 20 of frequency A are handed over to cell 20 of frequency C, some of the user terminals 82 in vehicle 51 are handed over to cell 20 of frequency B, and all of the user terminals 82 in vehicle 52 are handed over to cell 20 of frequency C. When vehicle 52 arrives at the transportation service facility 53, the user terminals 82 in vehicle 52 have been handed over to cell 20 of frequency C, so the deterioration of congestion in cell 20 of frequency A covering the transportation service facility 53 is suppressed, and the deterioration of communication of the user terminals 82 in vehicle 52 is also suppressed.

[0120] Next, as vehicles 50 and 51 continue along road 54 from the state shown in Figure 15 and transition to the state shown in Figure 16, some or all of the user terminals 82 in vehicles 50 and 51 that are located in a cell of frequency A will hand over to a cell of frequency B or frequency C, rather than to a cell of frequency A. In the example shown in Figure 16, some of the user terminals 82 in vehicle 50 that are located in a cell of frequency A will hand over to a cell of frequency B, and some of the user terminals 82 in vehicle 51 will hand over to a cell 20 of frequency B. Vehicle 51 arrives at the traffic service facility 53, but since the user terminals 82 in vehicle 51 have handed over to a cell 20 of frequency B, the deterioration of congestion in the cell 20 of frequency A covering the traffic service facility 53 is suppressed, and the deterioration of communication of the user terminals 82 in vehicle 51 is also suppressed.

[0121] Next, when vehicle 50 moves further from the state shown in Figure 16 and arrives at the transportation service facility 53, and the situation transitions to the state shown in Figure 17, some or all of the user terminals 82 in vehicle 50 that are located in a cell of frequency A will be handed over to a cell 20 of frequency B or frequency C, rather than to a cell of frequency A. In the example shown in Figure 17, some of the user terminals 82 in vehicle 50 that are located in a cell of frequency A will be handed over to a cell of frequency B. In this case, in the state shown in Figure 13, many of the user terminals 82 in vehicles 50, 51, and 52 that were located in a cell of frequency A will be handed over to a cell other than frequency A by the time vehicles 50, 51, and 52 arrive at the transportation service facility 53, as shown in Figure 17, thus preventing the worsening of congestion in the frequency A cell that covers the transportation service facility 53.

[0122] Figure 18 schematically shows an example of control of a wireless communication service by the control device 100. In the example shown in Figure 18, multiple users 80 carrying user terminals 82 are located at the event venue 30. Upon the end of the event, these multiple users 80 depart from the event venue 30 and travel along road 46 to the nearest station, station 43, completing a section 47.

[0123] In this example, section 47 is covered by multiple cells, including cells with different frequencies. In the example shown in Figure 13, section 47 is covered by four cells 20 with frequency A, three cells 20 with frequency B, and two cells 20 with frequency C.

[0124] In the example shown in Figure 18, the communication traffic of cell 20 of frequency A covering the event venue 30 is congested. As multiple users 80 move along section 47 in response to the end of the event, it is expected that multiple cells of frequency A covering section 47 will become congested sequentially, from cell 20 of frequency A covering the event venue 30 to cell 20 of frequency A covering the station 43, as the multiple users 80 move along.

[0125] Figures 19, 20, and 21 are explanatory diagrams for explaining the prior art. Figures 19, 20, and 21 show the process from the state shown in Figure 18, through which multiple users 80 carrying user terminals 82 travel along section 47 and arrive at station 43.

[0126] As mentioned above, in conventional mobile communication control, once a user terminal 82 is present on a certain frequency, it tends to continue using that frequency afterward. Therefore, multiple user terminals 82 tend to continue using frequency A, which they were present on once at the event venue 30, on the road 46 and at the station 43.

[0127] Therefore, as shown in the example from Figures 19 to 21, if no measures are taken, multiple user terminals 82 at the event venue 30, which were located in cell 20 of frequency A in Figure 18, will hand over to cell 20 of frequency A as the user 80 moves along section 47. As a result, multiple cell 20 of frequency A covering section 47 will become congested sequentially, from cell 20 of frequency A covering the event venue 30 to cell 20 of frequency A covering the station 43. In this case, the multiple user terminals 82 carried by multiple users 80 will constantly be subjected to congested communication traffic during the period when the user 80 moves along section 47, leading to a decrease in the user 80's satisfaction with the communication service.

[0128] Next, as an embodiment of the present invention, an embodiment in which Figure 18 is the starting state and the state transitions in the order of Figures 22, 23, and 24 will be described. In Figure 18, the control device 100 identifies congested cells where communication traffic is congested from among a plurality of cells including cells of different frequencies. For example, from the four cells 20 of frequency A, three cells 20 of frequency B, and two cells 20 of frequency C shown in Figure 18, the control device 100 identifies the two cells 20 of frequency A covering road 46 and the cell 20 of frequency A covering station 43 as congested cells, assuming that congestion is expected due to the movement of multiple users 80.

[0129] The specific method by which the control device 100 identifies a congested cell is the same as in the embodiment described above, where Figure 2 is the starting state, and the states transition in the order of Figures 4, 5, and 6.

[0130] The control device 100 identifies a cell from among multiple cells 20 that has the same frequency as the congested cell and from which multiple user terminals located in the area are expected to move to an area covered by the congested cell, as the source cell. For example, from among the four cells 20 with frequency A, the three cells 20 with frequency B, and the two cells 20 with frequency C shown in Figure 18, the control device 100 identifies the cell 20 with frequency A that covers the event venue 30 as the source cell.

[0131] The control device 100 may identify a cell 20 as the source cell from which multiple user terminals 82 located in the area are expected to move to the area covered by the congestion cell, based on calendar information including the date and time, and event information held in the surrounding area of ​​the area covered by the congestion cell. For example, based on the date and time of the day and event information, the control device 100 may predict congestion on the route from the event venue to the nearest station after the event ends on the day the event is held, and therefore identify a cell 20 on that route as the source cell.

[0132] The specific method by which the control device 100 identifies the source cell is the same as in the embodiment described above, where Figure 2 is the starting state, and the states transition in the order of Figures 4, 5, and 6.

[0133] The control device 100 controls multiple user terminals 82 located in the source cell to facilitate handover to a congested cell and a cell with a different frequency than the source cell. For example, the control device 100 controls a user terminal 82 located in the event venue 30 in Figure 18 to facilitate handover to a cell with a different frequency B or frequency C than frequency A.

[0134] The specific method for controlling the handover of the user terminal 82 by the control device 100 is the same as in the embodiment described above, where Figure 2 is the starting state and the states transition in the order of Figures 4, 5, and 6.

[0135] In the example shown in Figure 18, the user terminals 82 within the event venue 30 are controlled by the control device 100 to facilitate handover to frequency B or frequency C. Therefore, when a user 80 carrying a user terminal 82 leaves the event venue 30 and transitions to the state shown in Figure 22, some or all of the user terminals 82 of user 80, who are located in a frequency A cell and moving along section 47, will hand over to a frequency B or frequency C cell 20, rather than to frequency A. In the example shown in Figure 22, some of the user terminals 82 located in a frequency A cell will hand over to a frequency B cell. This helps to suppress congestion in the frequency A cell 20 covering the road 46.

[0136] Next, when the user 80 carrying the user terminal 82 moves further from the state shown in Figure 22 and transitions to the state shown in Figure 23, some or all of the user terminals 82 located in the frequency A cell will hand over to a frequency B or frequency C cell instead of frequency A. In the example shown in Figure 23, some of the user terminals 82 located in the frequency A cell will hand over to a frequency C cell. This will suppress congestion in the frequency A cell 20 that covers the road 46.

[0137] Next, when user 80, carrying user terminal 82, proceeds further from the state shown in Figure 23 and arrives at station 43, and the situation transitions to the state shown in Figure 24, some or all of the user terminals 82 located in the frequency A cell will be handed over to a cell 20 of frequency B or frequency C, rather than to a cell of frequency A. In the example shown in Figure 24, some of the user terminals 82 located in the frequency A cell will be handed over to a cell of frequency C. This will suppress congestion in the frequency A cell 20 that covers station 43.

[0138] Figure 25 schematically shows an example of control of a wireless communication service by the control device 100. In Figure 25, the differences from the example shown in Figure 2 will be mainly explained. In the example shown in Figure 25, section 45 is covered by the cell group 28.

[0139] The cell group 28 may include one or more cells 20 located between the congested cell and the source cell. In the example shown in Figure 20, as in the example shown in Figure 2, the control device 100 identifies the cell 20 with frequency A covering station 43 as the congested cell and the cell 20 with frequency A covering station 42 as the source cell.

[0140] In the example shown in Figure 25, cell group 28 includes four cells 20 with frequency A, three cells 20 with frequency B, and two cells 20 with frequency C. In the example shown in Figure 25, of the multiple cells 20 included in cell group 28, the two cells 20 with frequency C are already in a congested state.

[0141] The control device 100 may change parameters related to the handover of multiple user terminals 82 located in the source cell, depending on the status of the cell group 28. In the example shown in Figure 25, the control device 100 controls the parameters related to the handover so that multiple user terminals 82 can easily hand over to the cell 20 of frequency B, while avoiding the two cells 20 of frequency C that are already in a congested state among the multiple cells 20 included in the cell group 28.

[0142] In the example shown in Figure 25, the user terminals 82 inside the train 40 are controlled by the control device 100 to facilitate handover to frequency B. As a result, as the train 40 departs from station 42 and moves along the tracks 44 toward station 43, some or all of the user terminals 82 inside the train 40 that are in a frequency A cell will hand over to a frequency B cell.

[0143] In the state shown in Figure 25, where train 40 is located at station 42, most of the user terminals 82 inside train 40 that were in the frequency A cell will hand over to cell 20 of frequency B, rather than cell 20 of frequency C, before train 40 arrives at station 43, as shown in Figure 26. Therefore, it is possible to suppress the worsening of congestion in cell 20 of frequency C while also preventing further worsening of congestion in cell 20 of frequency A, which is a congested cell.

[0144] Figure 27 schematically shows an example of control of a wireless communication service by the control device 100. In Figure 27, the differences from the example shown in Figure 25 will be mainly explained. In the example shown in Figure 27, among the multiple cells 20 included in the cell group 28, cell 20 of frequency B and cell 20 of frequency C that cover station 43 are in a high-load state. A high-load state is a state in which the number of connected users is relatively large and the user throughput is relatively low, and although congestion has not yet occurred, it represents a state in which congestion is highly likely to occur if the number of user terminals 82 etc. located in the area increases further.

[0145] Figure 28 schematically shows an example of control of the wireless communication service by the control device 100. Figure 28 shows the state after the train 40 has moved from the state shown in Figure 27, traveled along the tracks 44, and arrived at station 43.

[0146] If the control device 100 simply modifies the parameters related to the handover of multiple user terminals 82 to facilitate handover to cells 20 with different frequencies than the congested cell and the source cell, then, for example, as shown in Figure 28, the handover destinations of multiple user terminals 82 may be biased towards frequency B, and the cell 20 with frequency B that covers station 43 may become congested.

[0147] The control device 100 may change parameters related to the handover of multiple user terminals 82 located in the source cell, depending on the status of the cell group 28. In the example shown in Figure 27, the control device 100 controls the parameters related to handover to both the frequency B cell 20 and the frequency C cell 20, which cover the station 43 that is already under heavy load, among the multiple cells 20 included in the cell group 28, so that the multiple user terminals 82 can easily hand over.

[0148] The control device 100 may determine a frequency that facilitates the handover of multiple user terminals 82 located in the source cell, depending on the status of the cell group 28. In the example shown in Figure 27, the control device 100 may determine a frequency that facilitates the handover of multiple user terminals 82 to both frequency B and frequency C, depending on the fact that both cell 20 with frequency B and cell 20 with frequency C, which cover station 43, are already under heavy load.

[0149] In this case, the control device 100 may control the parameters related to the handover of the user terminals 82 to make it easier for the user terminals 82 to hand over to the cell of the determined frequency. Depending on the status of the cell group 28, the control device 100 may determine the amount to change the parameters related to the handover of the user terminals 82 located in the source cell.

[0150] For example, the control device 100 modifies parameters related to the handover of multiple user terminals 82 so that multiple user terminals 82 located in the source cell can easily hand over to cells 20 with frequencies different from those of the congested cell and the source cell. For example, the control device 100 modifies the parameters related to the handover of multiple user terminals 82 in multiple stages. For example, the control device 100 modifies the parameters related to the handover of multiple user terminals 82 so that each of the multiple stages has a different value.

[0151] For example, the control device 100 first modifies the parameters related to the handover of the multiple user terminals 82 so that the parameters are at an intermediate value such that only some of the multiple user terminals 82 are likely to be handed over, while the remaining portion are likely to continue to be located at the same frequency as the source cell. The control device 100 then modifies the parameters related to the handover of the multiple user terminals 82 so that the remaining portion of the multiple user terminals 82 are likely to be handed over.

[0152] For example, in the example shown in Figure 27, the control device 100 first changes the parameters related to the handover of multiple user terminals 82 to a first value such that some of the user terminals 82 located in the source cell that wish to hand over to cell 20 of frequency B will hand over. Then, as the train 40 travels through section 45, these some user terminals 82 will hand over to cell 20 of frequency B. Next, the control device 100 changes the parameters related to the handover of multiple user terminals 82 to a second value such that the remaining some user terminals 82 will hand over. Then, as the train 40 travels through section 45, these remaining some user terminals 82 will hand over to cell 20 of frequency C.

[0153] This makes it possible to control the distribution of multiple user terminals 82 located in the source cell to multiple cells 20 with frequencies different from those of the congested cell and the source cell, thereby facilitating handover. Note that the first and second values ​​of the parameters related to handover do not necessarily have to be different; they may be the same.

[0154] For example, the control device 100 may change the parameters related to handover to the extent that congestion is not expected when a cell 20 with a frequency different from the frequencies of the congested cell and the source cell accepts the handover of some of the user terminals 82 located in the source cell. For example, in the example shown in Figure 27, there is a possibility of congestion if cell 20 with frequency B covering station 43 accepts the handover of an additional 20 user terminals 82, and there is a possibility of congestion if cell 20 with frequency C covering station 43 accepts the handover of 50 user terminals 82. In this case, the control device 100 may determine the amount to change the parameters related to handover so that the number of user terminals 82 that hand over to cell 20 with frequency B covering station 43 is likely to be less than 20, and may determine the amount to change the parameters related to handover so that the number of user terminals 82 that hand over to cell 20 with frequency C covering station 43 is likely to be less than 50.

[0155] In the example shown in Figure 27, the user terminals 82 inside the train 40 are controlled by the control device 100 to facilitate handover to cell 20 of frequency B and cell 20 of frequency C. Therefore, as the train 40 departs from station 42 and moves along the tracks 44 toward station 43, some of the user terminals 82 inside the train 40 that are in cell A will hand over to cell 20 of frequency B, and the remaining portion will hand over to cell 20 of frequency B.

[0156] As a result, in the state shown in Figure 27, where train 40 is located at station 42, some of the user terminals 82 within train 40 that were in the frequency A cell are handed over to the frequency B cell 20 by the time train 40 arrives at station 43, as shown in Figure 29, while the remaining portion are handed over to the frequency C cell 20. This prevents the frequency B cell 20 and frequency C cell 20 covering station 43, which was under heavy load, from becoming congested, while also preventing further deterioration of congestion in congested cells.

[0157] Figure 30 schematically shows an example of the functional configuration of the control device 100. In Figure 30, the control device 100 includes an information acquisition unit 110, a storage unit 120, a congestion cell identification unit 130, a source cell identification unit 140, and a handover control unit 150.

[0158] The information acquisition unit 110 may acquire various types of information. For example, the information acquisition unit 110 may acquire information related to the wireless communication service provided by the system 10. For example, the information acquisition unit 110 may acquire information regarding the geographical location of the wireless base stations 200 and information regarding the frequency-specific cells 20 formed by the wireless base stations 200.

[0159] The information acquisition unit 110 may acquire performance information for each of the multiple cells 20. The information acquisition unit 110 may acquire timetable information. The information acquisition unit 110 may acquire calendar information. The information acquisition unit 110 may acquire information on the congestion status of past time-series communication traffic for the multiple cells 20.

[0160] The information acquisition unit 110 may acquire information representing the connections between stations of public transportation. For example, the information acquisition unit 110 may acquire a train route map. For example, the information acquisition unit 110 may acquire a train timetable diagram.

[0161] The memory unit 120 may store various types of information. For example, the memory unit 120 may store various types of information acquired by the information acquisition unit 110. For example, the memory unit 120 may store various learning models used by the control device 100.

[0162] The memory unit 120 may store a learning model that takes performance information of multiple cells 20 as input and outputs at least one of the cells among the multiple cells 20 that are experiencing communication traffic congestion or are expected to experience congestion.

[0163] The congestion cell identification unit 130 identifies a congestion cell from among multiple cells 20, including cells 20 with different frequencies, where communication traffic is congested. The congestion cell identification unit 130 may identify a cell 20 that it has determined is congested based on performance information of the multiple cells 20 as a congestion cell.

[0164] The congestion cell identification unit 130 may identify congestion cells by inputting the performance information of multiple cells 20 acquired by the information acquisition unit 110 into a learning model stored in the storage unit 120.

[0165] The source cell identification unit 140 identifies a source cell from among multiple cells 20 that has the same frequency as a congested cell and is expected to move to an area covered by the congested cell where multiple user terminals 82 are located. The source cell identification unit 140 may identify multiple source cells. The source cell identification unit 140 may also identify a source cell based on changes in the congestion state of past time-series communication traffic of multiple cells 20.

[0166] The source cell identification unit 140 may, when a cell 20 covering a station is identified as a congested cell, identify a cell 20 covering a station identified based on the connection relationship with the station covered by the congested cell as the source cell. The source cell identification unit 140 may, when a cell 20 covering a station is identified as a congested cell, identify a cell covering a station identified based on the connection relationship with the station covered by the congested cell and timetable information as the source cell.

[0167] The source cell identification unit 140 may identify a cell 20 as the source cell in which multiple user terminals 82 located in the area are expected to move to an area covered by a congested cell, based on calendar information including the date and time.

[0168] The source cell identification unit 140 may identify a cell 20 as the source cell that covers an area identified based on the connection relationship of trunk roads to the area covered by the congested cell.

[0169] The handover control unit 150 may control multiple user terminals 82 located in the source cell to facilitate handover to a cell 20 with a different frequency than the congested cell and the source cell. The handover control unit 150 may control multiple user terminals 82 to modify parameters related to handover to a cell 20 with a different frequency than the congested cell and the source cell.

[0170] The handover control unit 150 may prioritize handing over user terminals 82 located in more congested source cells among the identified multiple source cells to cells 20 with different frequencies than the congested cell and the source cell.

[0171] The handover control unit 150 may control the event trigger to modify it so that it is easier to hand over to a cell 20 with a different frequency than the congested cell and the source cell. The handover control unit 150 may also indicate the destination cell 20 for the handover so that it is easier to hand over to a cell 20 with a different frequency than the congested cell and the source cell.

[0172] The handover control unit 150 may control the radio base station 200 that is generating the source cell to notify idle user terminals 82 located in the area covered by the source cell of cell reselection parameters that prioritize cell 20 with a different frequency than the source cell.

[0173] The handover control unit 150 may change parameters related to the handover of multiple user terminals 82 located in the source cell, depending on the status of the congested cell, the source cell, and the cell group 28.

[0174] The handover control unit 150 may determine a frequency that facilitates the handover of multiple user terminals 82 located in the source cell, depending on the status of the cell group 28. The handover control unit 150 may control the parameters related to the handover of the multiple user terminals 82 to change so that the multiple user terminals 82 can be easily handed over to the cell 20 of the determined frequency. The handover control unit 150 may determine the amount of change to the parameters related to the handover of the multiple user terminals 82 located in the source cell, depending on the status of the cell group 28.

[0175] Figure 31 schematically shows an example of the processing flow by the control device 100. In step 102 (steps may be abbreviated as S), the congestion cell identification unit 130 identifies a congestion cell where communication traffic is congested from among a plurality of cells 20, including cells with different frequencies.

[0176] In S104, the source cell identification unit 140 identifies a cell 20 from among multiple cells 20 that has the same frequency as the congested cell and is expected to move to an area covered by the congested cell.

[0177] In S106, the handover control unit 150 controls the multiple user terminals 82 located in the source cell to facilitate handover to a cell 20 with a different frequency than the congested cell and the source cell.

[0178] Figure 32 schematically shows an example of the hardware configuration of a computer 1200 that functions as a control device 100. A program installed on the computer 1200 can cause the computer 1200 to function as one or more "parts" of the apparatus according to this embodiment, or to cause the computer 1200 to execute operations associated with the apparatus according to this embodiment or such one or more "parts", and / or to cause the computer 1200 to execute a process or a stage of such process according to this embodiment. Such a program may be executed by the CPU 1212 to cause the computer 1200 to execute specific operations associated with some or all of the blocks in the flowcharts and block diagrams described herein.

[0179] The computer 1200 according to this embodiment includes a CPU 1212, RAM 1214, and a graphics controller 1216, which are interconnected by a host controller 1210. The computer 1200 also includes input / output units such as a communication interface 1222, a storage device 1224, a DVD drive, and an IC card drive, which are connected to the host controller 1210 via an input / output controller 1220. The DVD drive may be a DVD-ROM drive and a DVD-RAM drive, etc. The storage device 1224 may be a hard disk drive and a solid-state drive, etc. The computer 1200 also includes legacy input / output units such as a ROM 1230 and a keyboard, which are connected to the input / output controller 1220 via an input / output chip 1240.

[0180] The CPU 1212 operates according to the programs stored in the ROM 1230 and RAM 1214, thereby controlling each unit. The graphics controller 1216 acquires the image data generated by the CPU 1212 and stores it in the frame buffer provided in RAM 1214 or within itself, so that the image data is displayed on the display device 1218.

[0181] The communication interface 1222 communicates with other electronic devices via a network. The storage device 1224 stores programs and data used by the CPU 1212 in the computer 1200. The DVD drive reads programs or data from a DVD-ROM or the like and provides them to the storage device 1224. The IC card drive reads programs and data from an IC card and / or writes programs and data to an IC card.

[0182] The ROM 1230 stores boot programs and / or hardware-dependent programs of the computer 1200, which are executed by the computer 1200 upon activation. The input / output chip 1240 may also connect various input / output units to the input / output controller 1220 via USB ports, parallel ports, serial ports, keyboard ports, mouse ports, etc.

[0183] The program is provided on a computer-readable storage medium such as a DVD-ROM or IC card. The program is read from the computer-readable storage medium and installed on a storage device 1224, RAM 1214, or ROM 1230, which are examples of computer-readable storage media, and executed by the CPU 1212. The information processing described within these programs is read by the computer 1200, resulting in coordination between the program and the various types of hardware resources described above. The apparatus or method may be configured to realize the operation or processing of information in accordance with the use of the computer 1200.

[0184] For example, when communication is performed between a computer 1200 and an external device, the CPU 1212 may execute a communication program loaded into RAM 1214 and, based on the processing described in the communication program, instruct the communication interface 1222 to perform communication processing. Under the control of the CPU 1212, the communication interface 1222 reads transmission data stored in a transmission buffer area provided in a recording medium such as RAM 1214, storage device 1224, DVD-ROM, or IC card, transmits the read transmission data to the network, or writes received data received from the network to a reception buffer area provided on the recording medium.

[0185] Furthermore, the CPU 1212 may read all or necessary parts of a file or database stored on an external recording medium such as the storage device 1224, a DVD drive (DVD-ROM), or an IC card into the RAM 1214, and perform various types of processing on the data in the RAM 1214. The CPU 1212 may then write the processed data back to the external recording medium.

[0186] Various types of information, such as various types of programs, data, tables, and databases, may be stored on the recording medium and subjected to information processing. The CPU 1212 may perform various types of processing on the data read from RAM 1214, including various types of operations, information processing, conditional judgments, conditional branching, unconditional branching, information retrieval / replacement, etc., as described throughout this disclosure and specified by the program instruction sequence, and write the results back to RAM 1214. The CPU 1212 may also retrieve information in files, databases, etc., within the recording medium. For example, if multiple entries are stored in the recording medium, each having an attribute value of a first attribute associated with an attribute value of a second attribute, the CPU 1212 may search among the multiple entries for an entry that matches the specified condition for the attribute value of the first attribute, read the attribute value of the second attribute stored in that entry, and thereby obtain the attribute value of the second attribute associated with the first attribute that satisfies the predetermined condition.

[0187] The program or software module described above may be stored on or near the computer 1200 in a computer-readable storage medium. Alternatively, a recording medium such as a hard disk or RAM provided within a server system connected to a dedicated communication network or the Internet can be used as a computer-readable storage medium, thereby providing the program to the computer 1200 via the network.

[0188] In this embodiment, blocks in the flowchart and block diagram may represent a stage in a process in which an operation is performed or a "part" of a device that has the role of performing an operation. A particular stage and "part" may be implemented by a dedicated circuit, a programmable circuit supplied with computer-readable instructions stored on a computer-readable storage medium, and / or a processor supplied with computer-readable instructions stored on a computer-readable storage medium. The dedicated circuit may include digital and / or analog hardware circuits, and may include integrated circuits (ICs) and / or discrete circuits. The programmable circuit may include reconfigurable hardware circuits, such as field-programmable gate arrays (FPGAs) and programmable logic arrays (PLAs), which include logical AND, logical OR, exclusive OR, negated AND, negated OR, and other logical operations, flip-flops, registers, and memory elements.

[0189] A computer-readable storage medium may include any tangible device capable of storing instructions that can be executed by a suitable device, and as a result, a computer-readable storage medium having instructions stored therein will comprise a product that includes instructions that can be executed to create means for performing operations specified in a flowchart or block diagram. Examples of computer-readable storage media may include electronic storage media, magnetic storage media, optical storage media, electromagnetic storage media, semiconductor storage media, etc. More specific examples of computer-readable storage media may include floppy disks, diskettes, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), electrically erasable programmable read-only memory (EEPROM), static random access memory (SRAM), compact disk read-only memory (CD-ROM), digital multipurpose disc (DVD), Blu-ray® disc, memory stick, integrated circuit card, etc.

[0190] Computer-readable instructions may include assembler instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk®, Java®, C++, and traditional procedural programming languages ​​such as the C programming language or similar programming languages.

[0191] Computer-readable instructions may be provided locally or via a wide area network (WAN) such as a local area network (LAN) or the internet to a processor or programmable circuit of a general-purpose computer, special-purpose computer, or other programmable data processing device, so that the processor or programmable circuit of the programmable data processing device, such as a computer, can execute the instructions to generate means for performing operations specified in a flowchart or block diagram. Here, the computer may be a PC (personal computer), tablet computer, smartphone, workstation, server computer, general-purpose computer, or special-purpose computer, and may also be a computer system in which multiple computers are connected. Such a computer system in which multiple computers are connected is also called a distributed computing system and is a computer in a broad sense. In a distributed computing system, multiple computers execute a program collectively by each computer executing a part of the program and passing data during program execution between computers as needed.

[0192] Examples of processors include computer processors, central processing units, processing units, microprocessors, digital signal processors, controllers, and microcontrollers. A computer may have one or more processors. In a multiprocessor system with multiple processors, each processor executes a portion of the program, and the processors collectively execute the program by passing program execution data between them as needed. For example, in the execution of multitasks, each of the multiple processors may execute a portion of each task in small chunks by switching tasks at each time slice. In this case, which part of a program each processor executes changes dynamically. Which part of a program each of the multiple processors executes may also be statically determined by multiprocessor-aware programming.

[0193] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications or improvements can be made to the above embodiments. It will be clear from the claims that such modified or improved forms may also be included in the technical scope of the present invention.

[0194] It should be noted that the execution order of operations, procedures, steps, and stages in the apparatus, systems, programs, and methods shown in the claims, specifications, and drawings is not explicitly stated as "before" or "prior to," and that these can be implemented in any order unless the output of a previous process is used in a later process. Even if the operation flow in the claims, specifications, and drawings is described using phrases such as "first," and "next," for convenience, this does not mean that it is essential to perform the operations in that order. [Explanation of Symbols]

[0195] 10 System, 20 Cell, 28 Cell Group, 30 Event Venue, 40 Train, 41 Train, 42 Station, 43 Station, 44 Track, 45 Section, 46 Road, 47 Section, 50 Vehicle, 51 Vehicle, 52 Vehicle, 53 Transportation Service Facility, 54 Road, 55 Section, 80 User, 82 User Terminal, 90 Network, 100 Control Device, 110 Information Acquisition Unit, 120 Storage Unit, 130 Congested Cell Identification Unit, 140 Moving Source Cell Identification Unit, 150 Handover Control Unit, 200 Wireless Base Station, 1200 Computer, 1210 Host Controller, 1212 CPU, 1214 RAM, 1216 Graphics Controller, 1218 Display Device, 1220 Input / Output Controller, 1222 Communication Interface, 1224 Storage Device, 1230 ROM, 1240 Input / Output Chip

Claims

1. A congestion cell identification unit identifies a congestion cell where communication traffic is congested from among multiple cells, including cells with different frequencies. A source cell identification unit identifies, from among the plurality of cells, a cell having the same frequency as the congestion cell, and from which multiple user terminals located in the area are expected to move to an area covered by the congestion cell, as the source cell. A handover control unit controls multiple user terminals located in the source cell to facilitate handover to a cell with a different frequency than the congested cell and the source cell. A control device equipped with the following features.

2. The control device according to claim 1, wherein the handover control unit controls the parameters related to the handover of the plurality of user terminals so that the plurality of user terminals located in the source cell can easily hand over to the congested cell and the cell with a different frequency than the source cell.

3. Information acquisition unit that acquires performance information for each of the aforementioned multiple cells Equipped with, The control device according to claim 1, wherein the congested cell identification unit identifies a cell that has been determined to be experiencing communication traffic congestion based on the performance information of the plurality of cells as the congested cell.

4. A storage unit that stores a learning model that takes performance information of multiple cells as input and outputs at least one of the cells among the multiple cells that are experiencing communication traffic congestion or are predicted to experience congestion, An information acquisition unit that acquires performance information for each of the aforementioned multiple cells. Equipped with, The control device according to claim 1, wherein the congestion cell identification unit identifies the congestion cell by inputting the performance information of the plurality of cells acquired by the information acquisition unit into the learning model.

5. The control device according to claim 1, wherein the source cell identification unit identifies the source cell based on changes in the congestion state of past time-series communication traffic of the plurality of cells.

6. The control device according to claim 1, wherein the source cell identification unit identifies a cell that covers a station as the source cell when the congestion cell identification unit identifies a cell that covers a station as the congestion cell, based on the connection relationship between the congestion cell and the station it covers.

7. The control device according to claim 6, wherein when the congestion cell identification unit identifies a cell covering a station as the congestion cell, the unit identifies a cell covering a station identified based on the connection relationship between the congestion cell and the station it covers and timetable information as the source cell.

8. The control device according to claim 1, wherein the mobile source cell identification unit identifies a cell covering an area identified based on the connection relationship of trunk roads to the area covered by the congested cell as the mobile source cell.

9. The control device according to claim 1, wherein the handover control unit controls the radio base station generating the source cell to notify idle user terminals located in the area covered by the source cell of cell reselection parameters that prioritize cells with a different frequency than the source cell.

10. The control device according to any one of claims 1 to 9, wherein the handover control unit changes parameters related to the handover of the plurality of user terminals located in the source cell according to the status of a group of cells including the congested cell, the source cell, and one or more cells located between the congested cell and the source cell.

11. The control device according to claim 10, wherein the handover control unit determines a frequency that facilitates the handover of the plurality of user terminals located in the source cell, depending on the status of the cell group, and controls the plurality of user terminals to change parameters related to the handover of the plurality of user terminals so that they can be easily handed over to a cell of the determined frequency.

12. The control device according to claim 10, wherein the handover control unit determines the amount of change in parameters related to the handover of the plurality of user terminals located in the source cell, according to the status of the cell group.

13. A control method performed by a computer, A congestion cell identification step involves identifying a congested cell where communication traffic is congested from among multiple cells, including cells with different frequencies. A step of identifying a source cell from among the plurality of cells, which is a cell with the same frequency as the congestion cell and from which multiple user terminals located in the area are expected to move to an area covered by the congestion cell, A handover control step that controls multiple user terminals located in the source cell to facilitate handover to a cell with a different frequency than the congested cell and the source cell. A control method comprising the following features.

14. A program for causing a computer to execute the control method described in claim 13.

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