Control device, control method, and program

Abstract

A control device, which implements controls for a base station in a mobile communication system including a plurality of base stations, comprising: a suspension station determining unit configured to determine, on the basis of the traffic demand of each base station, a suspension station that is to suspend at least one frequency band as well as the parameters of at least one relief station that is to cover a coverage hole caused by the suspension of the suspension station; and a control transmitting unit configured to transmit the information of the suspension station determined by the suspension station determining unit as well as control information including said parameters.

Description

[Technical Field]

[0001] The present invention relates to a technique for controlling a radio base station (hereinafter referred to as a base station) that provides radio communication services to terminals in a mobile communication system. [Background technology]

[0002] Since traffic demands on base stations vary greatly depending on the time of day and location, base stations generally reserve capacity (computing resources, etc.) for traffic processing in accordance with peak traffic demands.

[0003] Therefore, in times / places where traffic demand is low, excess capacity is secured relative to the traffic demand, and power consumption corresponding to this capacity deteriorates the efficiency of power utilization for traffic processing.

[0004] To improve this power utilization efficiency, studies are being conducted to reduce power consumption by shutting down some base stations during times / locations with low traffic demand and covering the areas of the shut down base stations with surrounding base stations [1, 2]. Note that the names of references indicated by numbers in this specification are listed at the end of the specification.

[0005] Base stations generally cover areas with multiple frequency bands and can shut down each frequency band. However, communication devices connected to the shut-down base station will have to switch to another base station, which may result in a deterioration in communication quality.

[0006] Therefore, base station control, such as shutting down a base station or changing the parameters (tilt angle, transmission power, etc.) of surrounding base stations, is required to be performed while suppressing degradation of communication quality for terminals. [Prior art documents] [Non-patent literature]

[0007] [Non-Patent Document 1] Y. Gao, Y. Li, H. Yu, X. Wang and S. Gao, "Energy efficient joint optimization of electric antenna tilt and transmit power in 3GPP LTE-Advanced: A system level result," 2013 IEEE 9th International Colloquium on Signal Processing and its Applications, 2013, pp. 135-139, doi: 10.1109 / CSPA.2013.6530029. Summary of the Invention [Problem to be solved by the invention]

[0008] One existing method to improve power efficiency is to shut down base stations with low traffic demand and switch terminals connected to those base stations to nearby base stations (handover) [1]. This method assumes that there is a base station available for terminals to hand over to.

[0009] However, in areas where the cells of each base station do not overlap or where the density of base stations is low, handover is likely to be impossible due to coverage holes (areas where radio waves cannot reach) occurring when base stations stop transmitting, or due to insufficient base station bandwidth. For this reason, this method cannot be applied in the areas mentioned above.

[0010] Another existing method is to stop some base stations from transmitting by changing parameters such as the elevation angle (tilt angle) and transmission power of the base station antenna, while suppressing the deterioration of communication quality for terminals near those base stations ([2], Non-Patent Document 1).

[0011] In this method, the base stations to be stopped are determined in some way, and then parameters that suppress the communication quality of the terminal are calculated. However, since the communication quality of the terminal depends heavily on the base stations to be stopped, depending on the method for selecting the base stations to be stopped, it may not be possible to ensure communication quality.

[0012] The present invention has been made in view of the above points, and has an object to provide a technique that makes it possible to suppress deterioration in communication quality while reducing the power consumption of base stations. [Means for solving the problem]

[0013] According to the disclosed technology, there is provided a control device that controls a base station in a mobile communication system including a plurality of base stations, comprising: a stop station determination unit configured to determine, based on traffic demands of each base station, a stop station that will stop transmitting at least one frequency band and parameters of at least one relief station that will cover a coverage hole caused by the stop of transmitting at the stop station; a control transmission unit configured to transmit information about the suspended station determined by the suspended station determination unit and control information including the parameters; The out-of-service station determination unit determines parameters of the at least one rescue station that correspond to a situation in which the number of frequency bands that can be stopped by the out-of-service station is the largest among situations in which the coverage hole can be covered by the at least one rescue station. A control device is provided. [Effects of the Invention]

[0014] The disclosed technology makes it possible to suppress degradation of communication quality while reducing the power consumption of base stations. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a configuration diagram of a control system according to an embodiment of the present invention. [Figure 2] 10 is a flowchart illustrating the operation of a suspended station determining unit. [Figure 3] 10 is a flowchart illustrating the operation of a cover area calculation unit. [Figure 4] 10 is a flowchart illustrating the operation of a transmission suspension end determination unit. [Figure 5] 10 is a flowchart illustrating the operation of the embodiment. [Figure 6] FIG. 1 illustrates an example of a hardware configuration of an apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present invention (the present embodiment) will be described with reference to the drawings. The embodiment described below is merely an example, and the embodiment to which the present invention is applied is not limited to the following embodiment.

[0017] (Outline of the embodiment) In this embodiment, a control system that controls base stations determines the parameters (tilt angle, transmission power, etc.) of base stations to be stopped and base stations to be operated so that power consumption can be reduced under the constraint of ensuring the communication quality of terminals in accordance with the traffic demand of each base station, and performs control.

[0018] As will be explained in the following embodiments, control can be performed using current traffic demand, or control can be performed using future traffic demand (for example, for each time period).

[0019] (System configuration example) 1 shows an example of the configuration of a control system 100 according to this embodiment. Control system 100 according to this embodiment receives base station information (location information (latitude / longitude), current parameters (tilt angle (°), transmission power (W), etc.)) and traffic demand (traffic volume (bps) for each area / time period, number of active users (people) for each area / time period), and outputs instruction information for stopping / starting the base station, parameters for the base station after the change (tilt angle, transmission power, etc.), etc.

[0020] 1, the control system 100 includes an input receiving unit 10, a data processing unit 20, and a base station communication unit 30. The data processing unit 20 includes a traffic demand calculation unit 21, a suspended station determination unit 22, a cover area calculation unit 23, a suspension end determination unit 24, a control transmission unit 25, and a base station information DB 26. The base station communication unit 30 includes a transmission unit 31 and a reception unit 32.

[0021] A plurality of base stations to be controlled and control devices for controlling the base stations are connected to the base station communication unit 30. Each base station forms a communication area and performs wireless communication with terminals within the area.

[0022] The coverage area calculation unit 23 may be included in the out-of-service station determination unit 22. Alternatively, the "out-of-service station determination unit 22 + coverage area calculation unit 23" may be called the "out-of-service station determination unit." Furthermore, the control transmission unit 25 may include the function of the base station communication unit 30.

[0023] Furthermore, the control system 100 may be configured by one device (such as a computer) or multiple devices. The control system 100 configured by one device (such as a computer) may be called a control device. Furthermore, the data processing unit 20 may be called a control device.

[0024] Furthermore, the mobile communication system in this embodiment is not limited to a specific system, and may be, for example, any of 3G, 4G, 5G, 6G, and wireless LAN, or may be other systems.

[0025] The operation of each part is outlined below.

[0026] <Input Receiving Unit 10> The input receiving unit 10 periodically observes the traffic demand of each base station. The observation period is set to, for example, several minutes to several hours depending on the estimation / prediction accuracy required of the traffic demand calculation unit 21. The input receiving unit 10 notifies the traffic demand calculation unit 21 of the observation result.

[0027] <Traffic demand calculation unit 21> The traffic demand calculation unit 21 calculates the current traffic demand and future traffic demand of each base station based on the information from the input reception unit 10 .

[0028] <Shutdown Station Decision Unit 22> The out-of-service station determination unit 22 determines the base station to be shut down (called the out-of-service station) and the base station whose parameters will be changed (called the relief station) based on the observation / prediction results by the traffic demand calculation unit 21 and the calculation results by the cover area calculation unit 23.

[0029] <Cover area calculation unit 23> The cover area calculation unit 23 calculates whether a coverage hole will occur due to the base station stopping transmission, and if so, whether it can be covered by surrounding base stations.

[0030] <Band-off end determination unit 24> The suspension end determination unit 24 determines whether or not to restart the suspended station based on the calculation result by the traffic demand calculation unit 21.

[0031] <Control transmission unit 25> The control transmission unit 25 receives control content from the suspension station determination unit 22 or the suspension end determination unit 24, and transmits the control content to the base station communication unit 30. Based on the control content, the base station communication unit 30 executes control on the target base station.

[0032] <Base station information DB26> The base station information DB 26 stores and manages the location information of each base station, the parameters of each base station, outage station information, and relief station information. This information is updated upon receiving the control content determined by the outage station determination unit 22 or the outage end determination unit 24. Additionally, past information is also held in the base station information DB 26 according to the information used for calculations by the outage station determination unit 22 and the outage end determination unit 24.

[0033] (Detailed operation example) Next, the operation of each unit in the data processing unit 20 will be described in more detail.

[0034] <Traffic demand calculation unit 21> The traffic demand calculation unit 21 calculates the current estimated value of traffic demand for each base station and the future predicted value for each base station based on the traffic demand information periodically obtained from the input reception unit 10. The method for calculating the estimated value is not limited to a specific method, but for example, an exponential smoothing moving average or a state space model can be used. The calculation method for the future predicted value of traffic demand is also not limited to a specific method, but for example, a prediction method using SARIMA [5] or a prediction method using LSTM [6] can be used.

[0035] <Shutdown Station Decision Unit 22> The station-stopping-station determining unit 22 determines the base station to be stopped based on the calculation results by the traffic demand calculating unit 21 and the determination by the coverage area determining unit 23. The operation of the station-stopping-station determining unit 22 will be described in detail below, following the steps of the flowchart in FIG.

[0036] In S1, the suspension station determination unit 22 lists base stations whose demand is below a threshold based on the traffic demand of each base station calculated by the traffic demand calculation unit 21. If there is no base station with low demand, the subsequent calculations are not performed and the unit waits for information from the input reception unit 10.

[0037] In S2, the suspending station determination unit 22 determines whether or not a base station listed in S1 is a target for determining whether or not to suspend operation, one by one, starting from the base station with the lowest demand. A base station for which it is determined whether or not to suspend operation is called a suspending candidate station.

[0038] Here, among low-demand base stations, base stations that have already stopped operating and base stations that cannot stop operating (relief stations, etc.) are excluded from the targets for determining whether to stop operating, and the remaining base stations are considered to be candidate stations for stopping operating. Information on base stations that have already stopped operating and base stations that cannot stop operating (relief stations, etc.) can be obtained from the base station information DB 26. Furthermore, the base station information DB 26 is updated according to the control content determined by the station-to-stop determining unit 22.

[0039] In S3, the suspension station determining unit 22 lists the base stations (called peripheral stations) that exist around the suspension candidate station and whose traffic demand is below a threshold.

[0040] In S4, the outage station determination unit 22 transmits information about the outage candidate station and surrounding stations to the coverage area calculation unit 23, and receives a determination result as to whether outage is possible. This determination result includes a parameter indicating the frequency band in which the outage candidate station will be outaged and parameters of the relief station.

[0041] In S5, the suspending station determining unit 22 determines whether or not to suspend the suspending candidate station based on the determination result received in S4. The processes of S3 to S5 are performed for each suspending candidate station to determine a base station for which any frequency band will be suspended.

[0042] In S6, the suspension station determining unit 22 notifies the control transmitting unit 25 of the parameters of the base station to be suspended (such as the frequency band to be suspended) and the parameters of the relief station at that time.

[0043] <Cover area calculation unit 23> The cover area calculation unit 23 calculates whether a coverage hole will occur due to the outage of the outage candidate station, and (if it does occur) whether it can be covered by surrounding stations. The operation of the cover area calculation unit 23 will be explained in detail according to the procedure in the flowchart of Figure 3. If there are multiple pairs of "outage candidate station and one or more corresponding surrounding stations," the following process is executed for each pair.

[0044] In S11, the coverage area calculation unit 23 estimates the current coverage range for the outage candidate station and surrounding stations notified by the outage station determination unit 22. There are multiple methods for estimating the coverage range, and any method may be used.

[0045] For example, the coverage estimation method can be the geometric coverage estimation method described in [3] or the high-precision estimation method that takes into account propagation loss and radio interference described in [4]. These can be changed depending on the requirements for calculation time and estimation accuracy. If sufficient calculation time is available, the coverage is estimated based on the technique described in [4], and if not, the coverage is estimated based on the technique described in [3].

[0046] The coverage area of ​​a base station is, for example, an area in which terminals exist and in which communication can be performed between the base station and the terminals with a predetermined communication quality.

[0047] The coverage area may be defined not only from the viewpoint of communication quality but also as "the area in which communication can be covered, including the viewpoint of traffic accommodation."

[0048] In S12, the cover area calculation unit 23 uses the coverage area obtained in S11 to determine whether a coverage hole will occur if some or all of the frequency bands of the candidate station for suspension are suspended. A coverage hole is an area that is not covered by either the coverage area of ​​the candidate station for suspension or the coverage area of ​​surrounding stations.

[0049] Specifically, the coverage area calculation unit 23 stops the frequency bands of the candidate stations one by one and determines whether a coverage hole occurs for each situation. For example, the order in which frequency bands are stopped can be a method of stopping them in order from the highest frequency band.

[0050] If it is determined in S12 that no coverage hole will occur even if all frequency bands are stopped, the process proceeds to S13, where it is determined that this candidate station for stopping transmission can stop transmission of all frequency bands, and the frequency bands to be stopped by this candidate station for stopping transmission are notified to the stopping station determination unit 22. The station for stopping transmission determined here is a station for which parameter changes of surrounding stations are not required.

[0051] If it is determined in S12 that a coverage hole will occur due to the outage of any frequency band, the process proceeds to S14, where it is calculated whether the coverage hole can be covered by changing the parameters of surrounding stations for each frequency band outage situation.

[0052] The coverage area calculation unit 23 calculates the coverage rate for a coverage hole based on the coverage range of surrounding stations, for example, using the technology described in Reference [3]. Specifically, if the calculated coverage rate for a coverage hole is equal to or greater than a threshold, it is determined that the coverage hole can be covered. A surrounding station whose parameters are changed to achieve coverage is called a relief station. Parameters to be changed include, but are not limited to, the antenna tilt angle and transmission power. In addition, there may be one or more relief stations for a station that is down.

[0053] In S15, the coverage area calculation unit 23 adopts the control content of the situation that has the most frequency bands that can be stopped among the situations that have been determined to be covered by the relief station. If it is determined that coverage is not possible in all situations, no stopping of transmission is performed.

[0054] In S16, the cover area calculation unit 23 notifies the outage station determination unit 22 of whether the base station can be outage, the frequency band in which the outage candidate station will be outage (if outage is possible), and the parameters of the relief station.

[0055] <Band-off end determination unit 24> The transmission outage end determination unit 24 determines whether or not to restart a station that has stopped transmitting in at least one frequency band, based on the calculation result by the traffic demand calculation unit 21. The operation of the transmission outage end determination unit 24 will be described in accordance with the steps of the flowchart in FIG.

[0056] In S21, the outage end determination unit 24 determines whether the traffic demand of the outage station or the relief station exceeds a threshold. Information on the traffic demand of the current outage station and the relief station can be obtained from the base station information DB 26.

[0057] If it is determined that the traffic demand of the suspended station or the relief station exceeds the threshold, the process proceeds to S22, and the suspension end determination unit 24 notifies the control transmission unit 25 of the resumption of operation of the suspended station (resumption of operation of the frequency band that was suspended) and the change of the parameters of the relief station.

[0058] The parameter change may involve, for example, restoring the parameters to the values ​​they had before the coverage hole was covered. Furthermore, the outage end determination unit 24 updates the base station information DB 26 in accordance with the control results determined as described above. As a result of this update, for example, a base station that was managed in the base station information DB 26 as an outage station is now managed as a normal base station that is not an outage station.

[0059] If it is determined in S21 that the traffic demand of the suspended station or the relief station does not exceed the threshold, the situation is the same as when suspension control was implemented, so no action is taken and suspension continues.

[0060] <Control transmission unit 25> The control transmitter 25 receives the control content determined by the transmission-stopped station determining unit 22 and the transmission-stop end determining unit 24, and transmits the control content to the base station communication unit 30. More specifically, the control transmitter 25 starts transmission immediately upon receiving a notification from the transmission-stopped station determining unit 22 or the transmission-stop end determining unit 24. Note that if notifications are received simultaneously from the transmission-stopped station determining unit 22 and the transmission-stop end determining unit 24, the control transmitter 25 transmits the information together.

[0061] In addition, as in Example 2 described later, when the control transmission unit 25 receives control content for each time period, it receives the control content until the current time reaches that time period, and when the current time reaches that time period, it transmits the corresponding control content.

[0062] Hereinafter, examples 1 to 3 will be described as examples of base station control.

[0063] (Example 1: Base station control based on current traffic demand) In the first embodiment, the details of base station outages and parameter changes for relieving stations are calculated according to traffic demands that are periodically observed, and the corresponding base stations are controlled based on the calculation results. The processing of the first embodiment will be explained with reference to the flowchart in Figure 5. In this embodiment, the control cycle is set to, for example, several minutes to one hour, and online control is performed periodically. In other words, the processing of the flowchart in Figure 5 is executed periodically.

[0064] In S101, the input receiving unit 10 periodically acquires information from the base station communication unit 30. In S102, the traffic demand calculation unit 21 estimates the current traffic demand from the information acquired in S101.

[0065] In S103, the suspension station determination unit 22 determines whether there is a base station whose traffic demand is equal to or less than the threshold based on the estimation result in S102, and if there is, proceeds to S104. If there is no base station whose traffic demand is equal to or less than the threshold, the subsequent operations are not performed, and the process returns to S101 and waits for information from the input reception unit 10.

[0066] In S104, the out-of-service station determination unit 22 calculates the base stations that can be out-of-service and the parameters of the relief stations in that case based on the estimation result in S102. In S105, the out-of-service station determination unit 22 notifies the control transmission unit 25 of the calculation result.

[0067] In S106, the outage end determination unit 24 determines, based on the estimation result in S102, whether there is a stopped station or a replacement station with a traffic demand above the threshold, that is, whether to restart a base station that has already stopped operating. If restarting is to be performed, proceed to S107. If there is no stopped station or a replacement station with a traffic demand above the threshold, the subsequent operations are not performed and the process returns to the beginning.

[0068] In S107, the outage end determination unit 24 decides to restart the outage station, calculates the changed parameters of the relief station, and notifies the control transmission unit 25 of the control content (calculation result) in S108.

[0069] In S109, the control transmitter 25 transmits to the base station communication unit 30 control information indicating the suspension / restart / parameter change of the base station.

[0070] In S110, it is determined whether or not the operation of the base station control is to be terminated. If it is to be terminated, the operation of this system is terminated, and if it is not to be terminated, the processing described up to this point is repeated.

[0071] (Example 2: Base station control based on traffic demand forecast) In the second embodiment, the data processing unit 20 uses future predicted values ​​of traffic demand to prepare control patterns for stopping base station transmissions and changing tilt angles for each time period in advance. Then, it instructs the base station communication unit 30 to perform control for each time period. In the second embodiment, the control cycle is set to, for example, about several hours, and offline control is performed for each cycle.

[0072] In the second embodiment, unlike the first embodiment, it is possible to ensure sufficient time for calculating base station parameters in the cover area calculation unit 23, and to perform highly accurate control taking into consideration radio wave interference, etc. The flow of processing executed by the data processing unit 20 in the second embodiment is as follows.

[0073] First, the traffic demand calculation unit 21 calculates a predicted value of the traffic demand for each base station for each time period based on information on traffic demand that is periodically observed. The predicted value is stored in the base station information DB 26.

[0074] Next, the shutdown station decision unit 22 and shutdown end judgment unit 24 calculate the shutdown / restart / parameter change of the base station for each time period based on the predicted value of demand for each time period stored in the base station information DB 26, and notify the control details together to the control transmission unit 25. The control transmission unit 25 stores the notified control details.

[0075] The control transmitting unit 25 transmits the control content notified in advance to the base station communication unit 30 in accordance with the time period, and instructs the control.

[0076] (Embodiment 3: Base station control combining embodiments 1 and 2) In the third embodiment, offline control based on traffic demand prediction is performed as in the second embodiment, and when a sudden change in traffic demand or a base station failure occurs, online control is performed as in the first embodiment. This makes it possible to achieve both highly accurate control that takes into account radio wave interference and the like during normal times and the ability to deal with sudden demand fluctuations. The flow of processing executed by the data processing unit 20 in the third embodiment is as follows.

[0077] The input receiving unit 10 acquires observation information, for example, at intervals of several minutes, which is shorter than the control period of several hours in embodiment 2. The traffic demand calculation unit 21 estimates the current traffic demand of each base station based on this observation information.

[0078] If there is a base station whose current traffic demand exceeds the threshold, new control content is calculated using the same process as in Example 1, and notified to the control transmission unit 25, which then transmits the control content to the base station communication unit 30.

[0079] If there is no base station whose current traffic demand exceeds the threshold, the control content for each time period is determined based on the future traffic demand using the same processing as in Example 2, and the control content for each time period is transmitted to the base station communication unit 30 to instruct control.

[0080] (Example of hardware configuration) The control system 100 or the control device can be realized, for example, by causing a computer to execute a program. This computer may be a physical computer or a virtual machine on the cloud. Hereinafter, the control system 100 and the control device will be collectively referred to as "devices."

[0081] That is, the device can be realized by executing a program corresponding to the processing performed by the device using hardware resources such as a CPU and memory built into a computer. The program can be recorded on a computer-readable recording medium (such as a portable memory) and stored or distributed. The program can also be provided via a network such as the Internet or email.

[0082] Fig. 6 is a diagram showing an example of the hardware configuration of the computer. The computer in Fig. 6 includes a drive device 1000, an auxiliary storage device 1002, a memory device 1003, a CPU 1004, an interface device 1005, a display device 1006, an input device 1007, an output device 1008, and the like, all of which are interconnected via a bus BS.

[0083] A program for realizing processing on the computer is provided by a recording medium 1001 such as a CD-ROM or a memory card. When the recording medium 1001 storing the program is set in the drive device 1000, the program is installed from the recording medium 1001 to the auxiliary storage device 1002 via the drive device 1000. However, the program does not necessarily have to be installed from the recording medium 1001, but may be downloaded from another computer via a network. The auxiliary storage device 1002 stores the installed program as well as necessary files, data, etc.

[0084] The memory device 1003 reads and stores a program from the auxiliary storage device 1002 when an instruction to start the program is received. The CPU 1004 realizes the functions related to the device in accordance with the program stored in the memory device 1003. The interface device 1005 is used as an interface for connecting to a network, etc. The display device 1006 displays a GUI (Graphical User Interface) or the like according to the program. The input device 1007 is composed of a keyboard, mouse, buttons, a touch panel, etc., and is used to input various operation instructions. The output device 1008 outputs the results of calculations.

[0085] (Effects of the embodiment) The technology according to this embodiment makes it possible to suppress degradation of communication quality and reduce power consumption of base stations in a mobile communication system. The following three secondary effects are obtained.

[0086] Effect 1: By including constraints on ensuring communication quality for terminals in the control, the number of terminals whose communication quality deteriorates due to base station outages can be reduced compared to conventional technology.

[0087] Effect 2: By simultaneously optimizing the parameter settings of base stations that will be shut down and those that will remain operational, more base stations can be shut down compared to conventional technology, resulting in greater reductions in power consumption.

[0088] Effect 3: By optimizing the base stations to be shut down simultaneously with the parameter settings of other base stations, it becomes possible to shut down some base stations, even in areas where the cells of each base station do not overlap or in areas with low base station density, where conventional technology could not be applied, thereby reducing power consumption.

[0089] (Addendum) This specification discloses at least the control device, control method, and program described in the following items. (Section 1) A control device that controls a base station in a mobile communication system including a plurality of base stations, a stop station determination unit configured to determine, based on traffic demands of each base station, a stop station that will stop transmitting at least one frequency band and parameters of at least one relief station that will cover a coverage hole caused by the stop of transmitting at the stop station; a control transmission unit configured to transmit information about the suspended station determined by the suspended station determination unit and control information including the parameters; A control device comprising: (Section 2) The out-of-service station determination unit determines parameters of the at least one rescue station that correspond to a situation in which the number of frequency bands that can be stopped by the out-of-service station is the largest among situations in which the coverage hole can be covered by the at least one rescue station. 2. The control device according to claim 1. (Section 3) The stop-wave station determining unit determines a base station that will not cause a coverage hole even if all frequency bands are stopped as a stop-wave station that does not require changing the parameters of surrounding stations. 3. The control device according to claim 1 or 2. (Section 4) A suspension end determination unit configured to determine whether or not to restart a frequency band that has been suspended at a suspended station based on traffic demand. 4. The control device according to any one of claims 1 to 3, further comprising: (Section 5) The stop-wave station determining unit determines control information for each future time slot based on a predicted value of future traffic demand, and the control transmitting unit transmits the control information when the time of the time slot arrives. 10. The control device according to claim 1, wherein the control device is a control device for controlling a power supply. (Section 6) A control method executed by a control device that controls a base station in a mobile communication system including a plurality of base stations, comprising: a step of determining a station to be stopped based on traffic demand of each base station, the step of determining a station to be stopped that will stop transmitting at least one frequency band and parameters of at least one relieving station that will cover a coverage hole caused by the stop of the station to be stopped; a control transmission step of transmitting information about the suspended station determined in the suspended station determination step and control information including the parameters; A control method comprising: (Section 7) A program for causing a computer to function as each part of the control device described in any one of paragraphs 1 to 5.

[0090] Although the present embodiment has been described above, the present invention is not limited to such a specific embodiment, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

[0091] (References) [1] E. Oh and B. Krishnamachari, "Energy Savings through Dynamic Base Station Switching in Cellular Wireless Access Networks," 2010 IEEE Global Telecommunications Conference GLOBECOM 2010, 2010, pp. 1-5, doi: 10.1109 / GLOCOM.2010.5683654. [2] Y. Gao, Y. Li, H. Yu, X. Wang and S. Gao, "Energy joint optimization of electric antenna tilt and transmit power in 3GPP LTE-Advanced: A system level efficient result," 2013 IEEE 9th International Colloquium on Signal Processing and its Applications, 2013, pp. 135-139, doi: 10.1109 / CSPA.2013.6530029. [3] Masanao Iwamoto, Akito Suzuki, and Kunaki Harada, "Antenna Tilt Angle Control Method for Rapid Recovery of Communication Outage Areas," IEICE Society Conference, B-7-6, September 2020. [4] N. Dandanov, H. Al-Shatri, A. Klein, and V. Poulkov, "Dynamic Self-Optimization of the Antenna Tilt for Best Trade-off Between Coverage and Capacity in Mobile Networks," Wirel. Pers. Commun., vol. 92, no. 1, pp. 251-278, 2017. [5] Luo, X., Niu, L. & Zhang, S. An Algorithm for Traffic Flow Prediction Based on Improved SARIMA and GA. KSCE J Civ Eng 22, 2018, pp. 4107-4115. [6] HD Trinh, L. Giupponi and P. Dini, "Mobile Traffic Prediction from Raw Data Using LSTM Networks," 2018 IEEE 29th Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC), 2018, pp. 1827-1832, doi: 10.1109 / PIMRC.2018.8581000. [Explanation of symbols]

[0092] 100 Control System 10 Input reception section 20 Data Processing Unit 21 Traffic Demand Calculation Unit 22 Station Termination Decision Department 23 Coverage area calculation unit 24. Transmission outage end determination unit 25 Control transmitter 26 Base station information DB 30 Base station communication unit 31 Transmitter 32 Receiving unit 1000 Drive Device 1001 Recording media 1002 Auxiliary storage 1003 Memory device 1004 CPU 1005 Interface device 1006 Display device 1007 Input Device 1008 Output Device

Claims

1. A control device that controls a base station in a mobile communication system including a plurality of base stations, a stop station determination unit configured to determine, based on traffic demands of each base station, a stop station that will stop transmitting at least one frequency band and parameters of at least one relief station that will cover a coverage hole caused by the stop of transmitting at the stop station; a control transmission unit configured to transmit information about the suspended station determined by the suspended station determination unit and control information including the parameters; The out-of-band station determination unit determines parameters of the at least one rescue station that correspond to a situation in which the number of frequency bands that can be out-of-band by the out-of-band station is the largest among situations in which the coverage hole can be covered by the at least one rescue station. Control device.

2. A control device that controls a base station in a mobile communication system including a plurality of base stations, a stop station determination unit configured to determine, based on traffic demands of each base station, a stop station that will stop transmitting at least one frequency band and parameters of at least one relief station that will cover a coverage hole caused by the stop of transmitting at the stop station; a control transmission unit configured to transmit information about the suspended station determined by the suspended station determination unit and control information including the parameters; The stop-wave station determining unit determines control information for each future time slot based on a predicted value of future traffic demand, and the control transmitting unit transmits the control information when the time of the time slot arrives. Control device.

3. The stop-wave station determining unit determines a base station that will not cause a coverage hole even if all frequency bands are stopped as a stop-wave station that does not require changing the parameters of surrounding stations. The control device according to claim 1 or 2.

4. A suspension end determination unit configured to determine whether or not to restart a frequency band that has been suspended at a suspended station based on traffic demand. The control device according to any one of claims 1 to 3, further comprising:

5. A control method executed by a control device that controls a base station in a mobile communication system including a plurality of base stations, comprising: a step of determining a station to be stopped based on traffic demand of each base station, the step of determining a station to be stopped that will stop transmitting at least one frequency band and parameters of at least one relieving station that will cover a coverage hole caused by the stop of the station to be stopped; a control transmission step of transmitting control information including information on the suspended station determined in the suspended station determination step and the parameter, In the step of determining a station to be stopped, the control device determines parameters of the at least one relief station that correspond to a situation in which the number of frequency bands that can be stopped by the stopped station is the largest among situations in which the coverage hole can be covered by the at least one relief station. Control method.

6. A control method executed by a control device that controls a base station in a mobile communication system including a plurality of base stations, comprising: a step of determining a station to be stopped based on traffic demand of each base station, the step of determining a station to be stopped that will stop transmitting at least one frequency band and parameters of at least one relieving station that will cover a coverage hole caused by the stop of the station to be stopped; a control transmission step of transmitting control information including information on the suspended station determined in the suspended station determination step and the parameter, In the step of determining a station to be stopped, the control device determines control information for each future time slot based on a predicted value of future traffic demand, and in the step of transmitting control information, the control device transmits the control information when the time of the time slot arrives. Control method.

7. A program for causing a computer to function as each unit in the control device according to any one of claims 1 to 4.

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