Control device and control method

Abstract

This control device comprises: an information collection unit that acquires cooperation information pertaining to a plurality of communication stations connected directly or via another device to one or more terminals, and flow information pertaining to the flow of the one or more terminals; and an analysis unit that determines the frequency of sleep control determination on the basis of the acquired flow information, and determines whether sleep control based on the cooperation information can be executed at the determined frequency.　

Description

Control device and control method

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

[0002] Conventionally, a technique for controlling the sleep of a base station based on the traffic distribution within a cell has been proposed (see, for example, Non-Patent Document 1). In the technique of Non-Patent Document 1, each cell includes multiple users with different rates, and the timing of the sleep operation of the base station is determined based on the predicted results of the traffic distribution within the cell.

[0003] Y. Zhu, and S. Wang, “Joint Traffic Prediction and Base Station Sleeping for Energy Saving in Cellular Networks”, ICC, 2021.

[0004] In conventional technologies, sleep control is performed during times of relatively low traffic, such as at night, or in predetermined time units. As a result, sleep control decisions are made infrequently, resulting in limited power-saving effects.

[0005] In view of the above circumstances, an object of the present invention is to provide a technique that can improve the effect of power saving.

[0006] One aspect of the present invention is a control device that includes an information collection unit that acquires coordination information regarding multiple communication stations that are connected to one or more terminals directly or via other devices, and flow information regarding the flow of the one or more terminals, and an analysis unit that determines the frequency at which sleep control decisions are made based on the acquired flow information, and determines whether or not sleep control based on the coordination information can be executed at the determined frequency.

[0007] One aspect of the present invention is a control method that acquires coordination information regarding multiple communication stations connected to one or more terminals directly or via other devices and flow information regarding the flow of the one or more terminals, determines the frequency at which sleep control decisions are made based on the acquired flow information, and determines whether or not sleep control based on the coordination information can be executed at the determined frequency.

[0008] The present invention makes it possible to improve the effect of power saving.

[0009] 1 is a diagram for explaining an overall configuration and an overview of processing of a mobile NW system according to a first embodiment. FIG. 1 is a diagram for explaining an example of a configuration of a mobile NW system according to the first embodiment. FIG. 2 is a flowchart showing an example of the flow of sleep control determination frequency processing executed by a management control device according to the first embodiment. FIG. 3 is a flowchart showing an example of the flow of sleep processing executed by a management control device according to the first embodiment. FIG. 4 is a flowchart showing an example of the flow of sleep release processing executed by a management control device according to the first embodiment. FIG. 5 is a diagram for explaining an overall configuration and an overview of processing of a mobile NW system according to a second embodiment. FIG. 6 is a diagram for explaining an example of a configuration of a mobile NW system according to a second embodiment. FIG. 7 is a diagram for explaining an overall configuration and an overview of processing of a mobile NW system according to a second embodiment. FIG. 8 is a diagram for explaining an example of a configuration of a mobile NW system according to a second embodiment. FIG. 9 is a flowchart showing an example of the flow of sleep processing executed by a management control device according to the second embodiment. Fig. 1 is a diagram for explaining an overview of the overall configuration and processing of a wired NW system in an embodiment. Fig. 2 is a diagram showing an example of the configuration of a wired NW system in a third embodiment. Fig. 3 is a flowchart showing an example of the flow of sleep processing executed by a management control device in a third embodiment. Fig. 4 is a flowchart showing an example of the flow of sleep release processing executed by a management control device in a third embodiment.

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] (Outline of the First Embodiment) FIG. 1 is a diagram for explaining an overview of the overall configuration and processing of a mobile network system in the first embodiment. First, the overall configuration of the mobile network system will be explained. The mobile network system is an example of a communication system. The mobile network system is, for example, a fifth-generation mobile communication system (hereinafter referred to as "5G"). The mobile network system includes one or more radio stations 12, a forwarding device 13, multiple distributed stations 14, a central station 15, a core device 16, and a management control device 20.

[0012] Optical fibers that transmit optical signals are connected between each radio station 12 and the transfer device 13, between the transfer device 13 and each distributed station 14, between each distributed station 14 and the central station 15, and between the central station 15 and the core device 16. Electrical lines or optical fibers that transmit electrical signals are connected between the transfer device 13 and the management control device 20, between the distributed stations 14 and the management control device 20, and between the management control device 20 and the external server 25. The example shown in Fig. 1 shows a case where there are four radio stations 12 and two distributed stations 14. Note that multiple transfer devices 13 may be provided, but the following explanation will be given using a case where there is one transfer device 13.

[0013] Each wireless station 12 has one or more antennas and performs wireless communication with one or more terminals 11. For example, each wireless station 12 receives signals transmitted from one or more terminals 11 and transmits the received signals to a remote station 14 connected via a transfer device 13. Each wireless station 12 transmits the signals received via the transfer device 13 to one or more terminals 11. When the wireless station 12 has multiple antennas, the wireless station 12 may perform wireless communication with one or more terminals 11 by beamforming. The wireless station 12 is, for example, an RU (Radio Unit) in the 5G communication standard. The wireless station 12 is one aspect of another device.

[0014] The transfer device 13 is provided between the radio station 12 and the distributed station 14. The transfer device 13 is a switch that connects the radio station 12 and the distributed station 14 via an optical path. The transfer device 13 controls the optical path in accordance with control instructions (hereinafter referred to as "optical path control information") related to the optical path transmitted from the management control device 20. For example, the optical path control performed by the transfer device 13 includes switching of the optical path and formation of a new optical path. The transfer device 13 controls the connection between the radio station 12 and the distributed station 14 by controlling the optical path. For example, upon receiving optical path control information transmitted from the management control device 20, the transfer device 13 performs switching so that an optical path is connected between the radio station 12, which is the optical path switching destination, and the distributed station 14.

[0015] The remote station 14 receives uplink signals transmitted from one or more wireless stations 12 via the transfer device 13. The remote station 14 transmits downlink signals to one or more wireless stations 12 via the transfer device 13. Note that the uplink signals transmitted from one or more wireless stations 12 are signals transmitted by the terminal 11, and the downlink signals are signals addressed to the terminal 11.

[0016] Each distributed station 14 transitions to a sleep state in accordance with a sleep instruction transmitted from the management control device 20. The sleep state is a state in which power can be saved by stopping some functions or stopping the entire device. Each distributed station 14 cancels the sleep state in accordance with a sleep cancellation instruction transmitted from the management control device 20. Canceling the sleep state means restarting a stopped function. The distributed station 14 is, for example, a Distributed Unit (DU) in the 5G communication standard. Information that the management control device 20 acquires from the distributed station 14 is called cooperation information. The cooperation information is information related to each distributed station 14, and is, for example, information indicating the state of communication between each distributed station 14 and the terminal 11.

[0017] The coordination information in the first embodiment includes, for example, information on the traffic volume of each distributed station 14. Hereinafter, the traffic volume information is referred to as traffic information. Note that, for example, traffic information is described in DCI (Downlink Control Information) or O-RAN CTI (O-RAN.WG4.CTI-TCP.0-v01.00). In the O-RAN CTI, it refers to schedule information. Furthermore, each distributed station 14 controls the optical path in accordance with an optical path control instruction transmitted from the management and control device 20. For example, each distributed station 14 stops setting up an optical path between itself and the transfer device 13 in response to receiving the optical path control instruction. Stopping the setting up of an optical path in each distributed station 14 means not irradiating light onto the path from the distributed station 14 to the transfer device 13 (stopping optical irradiation).

[0018] The central station 15 aggregates the uplink signals transmitted from the respective distributed stations 14 and transmits the aggregated signals to the core device 16. The central station 15 transmits the downlink signals transmitted from the core device 16 to the target distributed station 14. The central station 15 is, for example, a CU (Centralized Unit) in the 5G communication standard.

[0019] The core device 16 performs signal processing on the uplink signals aggregated by the aggregation station 15. The core device 16 transmits the signals obtained as a result of the signal processing on the uplink signals to a server (not shown). The core device 16 transmits the signals transmitted from the server (not shown) to the aggregation station 15.

[0020] The core device 16 performs predetermined signal processing on a signal received from a server (not shown). The core device 16 transmits a signal obtained as a result of performing the signal processing on the signal received from the server (not shown) as a downlink signal to the central station 15. The signal processing is, for example, the transfer of user data in a user plane function (UPF) of the 5G core network.

[0021] The management control device 20 is a device that manages the entire mobile NW system. The management control device 20 acquires cooperation information from each distributed station 14. The management control device 20 uses a cooperation interface when acquiring cooperation information from each distributed station 14. The cooperation interface is an interface that connects the management control device 20 and each distributed station 14. The management control device 20 determines whether optical path control and sleep control are necessary based on the acquired cooperation information. For example, the management control device 20 may determine that optical path control is necessary when it determines that sleep control is necessary. When it determines that optical path control and sleep control are necessary, the management control device 20 performs optical path control processing and sleep control processing. The optical path control processing is processing that switches optical paths between the radio station 12 and the distributed station 14 or generates optical paths. The sleep control processing is processing that instructs the distributed station 14 that is the target of sleep control to go to sleep or cancels the sleep state.

[0022] Furthermore, the management control device 20 acquires information regarding the flow of terminals 11 (hereinafter referred to as "flow information") from the external server 25. Flow information is information that can be used to estimate an increase or decrease in the number of terminals 11, such as timetable information, traffic information, or event information. The terminals 11 are portable terminal devices. Therefore, it is expected that the terminals 11 will not remain in a fixed location but will move depending on the time. For example, when there is an event, people tend to gather in a unique location (e.g., the location where the event is held), so the terminals 11 will gather in a unique location. Based on such flow information, the management control device 20 determines the frequency at which it determines whether sleep control is necessary (hereinafter referred to as "sleep control determination frequency"). Here, a specific example will be given of a method for determining the sleep control determination frequency.

[0023] (When a timetable is used as traffic information) Since train timetables hardly change unless there are delays, the management control device 20 only needs to collect them once. Note that the timetable is not limited to train timetables, and can be a timetable for any means of transportation such as a bus. Here, a train timetable will be used as an example. Since the number of people tends to increase when a train arrives and decrease when a train does not arrive, there is a possibility that the traffic volume at a station will increase or decrease. Therefore, the management control device 20 can increase the frequency of sleep control decisions in accordance with the train arrival and departure times. If the frequency of sleep control decisions is increased when trains arrive, the timing of sleep release decisions can be increased. If the frequency of sleep control decisions is increased when trains depart, the timing of sleep decisions can be increased. Note that the management control device 20 may make sleep decisions using the traffic prediction results up to the arrival and departure time of the next train.

[0024] (When traffic information is used as flow information) Traffic volume may increase or decrease depending on whether or not there is congestion. Therefore, the management control device 20 collects traffic information in real time to determine whether or not there is congestion, and performs sleep control judgment in areas where there is no congestion. Traffic information (https: / / www.jartic.or.jp / ) includes information on congested areas, and it is assumed that traffic volume will decrease when the congestion clears. Therefore, the management control device 20 can increase the frequency of sleep control judgment when the congestion information disappears. This can increase the timing of sleep judgment. Furthermore, the above-mentioned traffic information also provides information indicating the congestion status in addition to information regarding congestion. If future congestion is predicted based on the information indicating the congestion status, it is assumed that traffic volume will increase. Therefore, the management control device 20 can increase the frequency of sleep control judgment when congestion is predicted. This can increase the timing of sleep release judgment.

[0025] The management control device 20 may use machine learning or the like to learn trends in locations and times where congestion is likely to occur based on traffic information, and determine the sleep control decision frequency based on the learning results. If the congestion trend is known, the management control device 20 may predict the traffic volume until the next congestion occurs and make a sleep decision. If there are plans for traffic restrictions or the like, the management control device 20 may store that information and increase the sleep control decision frequency as the time for lifting the restrictions approaches.

[0026] (When event information is used as traffic information) Since the date and time of an event or the like basically do not change, the management control device 20 only needs to collect the data once. There is a lot of movement of people around the start and end times of an event such as a concert, and traffic volume is likely to increase or decrease. Therefore, the management control device 20 may increase the frequency of sleep control decisions to match the start and end times of the event. If sleep control decisions are made more frequently at the start time of the event, the timing of sleep release decisions can be increased. If sleep control decisions are made more frequently at the end time of the event, the timing of sleep decisions can be increased. Note that in the case of a concert, communication volume decreases after the start of the concert, so the management control device 20 may increase the frequency of sleep control decisions around the scheduled start and end times. Furthermore, the management control device 20 may predict traffic volume based on the end time and make a sleep decision.

[0027] The external server 25 is a server that holds or acquires traffic information. The external server 25 transmits the held or acquired traffic information to the management control device 20. For example, if the traffic information is a timetable, the external server 25 may transmit the timetable information to the management control device 20 once, and then not transmit the timetable information to the management control device 20 until the timetable is updated. For example, if the traffic information is event information, the external server 25 may transmit the registered event information to the management control device 20 each time the event information is registered, or may transmit event information for a certain period (e.g., one month) to the management control device 20 in a lump. For example, if the traffic information is traffic information, the external server 25 may transmit traffic information and delay information (such as personal injury accidents and natural disasters) of transportation (e.g., trains, buses, etc.) to the management control device 20 in real time.

[0028] Next, an overview of the processing of the mobile network system will be explained. The upper diagram of Fig. 1 shows the connection state of the mobile network system before optical path switching, and the lower diagram of Fig. 1 shows the connection state of the mobile network system after optical path switching. The upper diagram of Fig. 1 shows an example in which radio stations 12-1 and 12-2 are connected to remote station 14-1, and radio stations 12-3 and 12-4 are connected to remote station 14-2.

[0029] The management control device 20 determines the sleep control determination frequency based on the flow information transmitted from the external server 25. Then, the management control device 20 determines whether or not to perform optical path switching control processing in accordance with the determined sleep control determination frequency. For example, the management control device 20 determines whether or not to perform optical path switching control processing based on the latest cooperation information collected from each remote station 14 at a timing according to the determined sleep control determination frequency.

[0030] The management control device 20 determines, based on the cooperation information collected from each distributed station 14, that sleep control is necessary when one distributed station 14 can accommodate the traffic of the other distributed stations 14. That is, the management control device 20 performs optical path control processing and sleep control processing when one distributed station 14 can accommodate the traffic of the other distributed stations 14 based on the cooperation information collected from each distributed station 14. In this way, by accommodating the traffic of the other distributed stations 14 in one distributed station 14, it is possible to transition the other distributed stations 14 that no longer have traffic to a sleep state.

[0031] When performing optical path control processing, the management control device 20 instructs the transfer device 13 to switch the optical path. The transfer device 13 switches the optical path between the radio station 12 and the remote station 14 in accordance with the instruction from the management control device 20. After completing the optical path switching, the transfer device 13 notifies the management control device 20 of the completion of the optical path switching. Note that, because the optical path switching changes the connection destination of the terminal 11, the management control device 20 may instruct the remote station 14, which is the target of the optical path switching, to change the connection.

[0032] When the management control device 20 receives a notification of completion of optical path switching from the transfer device 13, it transmits a sleep permission notification to the distributed station 14 that can transition to a sleep state. The sleep permission notification is a signal including an instruction to transition the distributed station 14 to a sleep state. As a result, the distributed station 14 that can transition to a sleep state transitions to the sleep state.

[0033] The lower diagram of Figure 1 shows an example in which radio stations 12-1 to 12-4 are connected to the remote station 14-1 and the remote station 14-2 has transitioned to a sleep state. In this way, the mobile network system 100 determines the frequency of sleep control decisions based on flow information acquired from the external server 25. Then, the management and control device 20 transitions the remote stations 14 that can transition to a sleep state to a sleep state by connecting the terminals 11 connected to the remote stations 14 that can transition to a sleep state to other remote stations 14 based on cooperation information collected from each remote station 14 in accordance with the determined frequency. Hereinafter, the remote station 14 that is the source of switching the optical path will be referred to as a switching source remote station, and the remote station 14 that is the destination of switching the optical path will be referred to as a switching destination remote station.

[0034] (Details of the First Embodiment) Fig. 2 is a diagram showing an example of the configuration of a mobile NW system 100 in the first embodiment. The mobile NW system 100 in the first embodiment includes one or more wireless stations 12, a transfer device 13, a plurality of distributed stations 14, a central station 15, a core device 16, a management and control device 20, and an external server 25. The wireless stations 12, the transfer device 13, the distributed stations 14, the central station 15, the core device 16, and the external server 25 have been described in Fig. 1, and therefore description thereof will be omitted.

[0035] The management control device 20 includes an information collection unit 21, an analysis unit 22, and a control unit 23. The information collection unit 21 includes an acquisition unit 211. The acquisition unit 211 acquires various types of information. The acquisition unit 211 collects cooperation information from, for example, the remote stations 14 at a predetermined cycle or at any timing. The acquisition unit 211 collects traffic information of each remote station 14 as cooperation information. Furthermore, the acquisition unit 211 acquires flow information from an external server 25.

[0036] The analysis unit 22 includes an information storage unit 221 and an information analysis unit 222. The information storage unit 221 records the coordination information and traffic flow information collected by the acquisition unit 211 in a predetermined storage device. The information analysis unit 222 determines the sleep control determination frequency based on the traffic flow information recorded in the information storage unit 221. The specific determination method is as described above. For example, the information analysis unit 222 may increase the sleep control determination frequency when an increase or decrease in traffic is expected. Furthermore, the information analysis unit 222 analyzes the state of communication between each remote station 14 and the terminal 11 based on the coordination information in accordance with the determined sleep control determination frequency. Specifically, the information analysis unit 222 determines whether optical path control and sleep control are necessary based on the coordination information.

[0037] For example, the information analysis unit 222 determines that optical path control and sleep control are necessary when all of the terminals 11 accommodated in one distributed station 14 can be accommodated in one of the distributed stations 14. In this case, the information analysis unit 222 notifies the control unit 23 of control information including an optical path control instruction and a sleep instruction. The optical path control instruction is an instruction to request switching of the optical path, and includes, for example, information indicating the distributed station 14 that is the source of the optical path switching and information indicating the distributed station 14 that is the destination of the optical path switching.

[0038] Furthermore, the information analysis unit 222 determines that optical path control and sleep control are necessary when the traffic volume of a certain remote station 14 exceeds a threshold. In this case, the information analysis unit 222 notifies the control unit 23 of control information including an optical path control instruction and a sleep release instruction. The sleep release instruction is an instruction to release the sleep state, and includes, for example, information indicating the remote station 14 to be released from sleep.

[0039] The control unit 23 includes an optical path control unit 231 and a sleep control unit 232. The optical path control unit 231 determines the distributed station 14 that serves as the source of optical path switching and the distributed station 14 that serves as the destination of optical path switching based on the analysis results of the information analysis unit 222. For example, the optical path control unit 231 determines the distributed station 14 that serves as the source of optical path switching based on information indicating the distributed station 14 that serves as the source of optical path switching, which is included in the control information notified by the information analysis unit 222. For example, the optical path control unit 231 determines the distributed station 14 that serves as the destination of optical path switching based on information indicating the distributed station 14 that serves as the destination of optical path switching, which is included in the control information notified by the information analysis unit 222. The optical path control unit 231 holds information about the radio stations 12 connected to the distributed stations 14.

[0040] The optical path control unit 231 transmits optical path control information including information indicating the remote node 14 to which the determined optical path is to be switched to the transfer device 13. As a result, the optical path control unit 231 instructs the transfer device 13 to switch the optical path.

[0041] Based on the analysis result of the information analysis unit 222, the sleep control unit 232 causes the remote station 14 that is the target of sleep control to put into sleep mode or to cancel sleep mode.

[0042] 3 is a flowchart showing an example of the flow of sleep control determination frequency processing executed by the management control device 20 in the first embodiment. The processing in FIG. 3 is repeatedly executed at a predetermined cycle. Note that, here, an example will be described in which there are four remote stations 14, and traffic information is used as the cooperation information.

[0043] The acquisition unit 211 acquires cooperation information from each of the remote stations 14-1 to 14-4 at a predetermined cycle. Furthermore, the acquisition unit 211 acquires flow information from the external server 25 (step S101). For example, the acquisition unit 211 may collect cooperation information once per unit time, which is the predetermined cycle, or at any timing. The unit time here refers to, for example, slot length, subframe length, frame length, 1 millisecond, 1 second, or 1 minute. Furthermore, the acquisition unit 211 only collects flow information once if it does not change much, such as timetables, but collects information that changes in real time, such as traffic information and delay information for transportation (e.g., trains, buses, etc.), every unit time. The acquisition unit 211 stores the acquired cooperation information and flow information for each remote station 14 in the information storage unit 221 (step S102).

[0044] The information analysis unit 222 determines the sleep control decision frequency based on the traffic information stored in the information storage unit 221 (step S103). Specifically, if the traffic information is, for example, a train timetable, the information analysis unit 222 determines whether the traffic volume at the station increases or decreases because the number of people increases when a train arrives and decreases when there is no train. Therefore, the information analysis unit 222 increases the frequency of sleep control decisions to match the train arrival and departure times. Increasing the frequency of sleep control decisions means increasing the number of times that sleep control decisions are made within a given period of time.

[0045] Fig. 4 is a flowchart showing an example of the flow of sleep processing executed by the management control device 20 in the first embodiment. The processing in Fig. 4 is executed at a timing according to the sleep control determination frequency determined in Fig. 3. Note that, here, an example will be described in which there are four remote stations 14, and traffic information is used as the cooperation information.

[0046] The information analysis unit 222 acquires the latest cooperation information for each remote station 14 stored in the information storage unit 221 (step S201). In the management control device 20, cooperation information is collected at a predetermined cycle before the processing of Fig. 4 is executed. Therefore, the information storage unit 221 accumulates cooperation information for each remote station 14 at each predetermined cycle. Therefore, when the processing of Fig. 4 is started, the information analysis unit 222 acquires the latest cooperation information for each remote station 14 at the start of the processing of Fig. 4.

[0047] Furthermore, the information analysis unit 222 may acquire the cooperation information again in accordance with the frequency of the sleep control determination. When acquiring the cooperation information again in accordance with the frequency of the sleep control determination, the information analysis unit 222 requests the information collection unit 21 to collect the cooperation information at the timing when the sleep control determination is made. The information collection unit 21 acquires the cooperation information from each remote station 14 in response to the request from the information analysis unit 222 and stores the information in the information storage unit 221. The information analysis unit 222 acquires the cooperation information stored in the information storage unit 221. This allows the information analysis unit 222 to acquire the cooperation information in accordance with the frequency of the sleep control determination.

[0048] The information analysis unit 222 calculates the traffic volume of each of the remote stations 14-1 to 14-4 based on the latest obtained cooperation information for each remote station 14. Then, the information analysis unit 222 sorts the remote stations 14-1 to 14-4 in ascending order of the calculated traffic volumes (step S202).

[0049] The information analysis unit 222 determines an addition target A for the traffic volume (step S203). The addition target A is, for example, the remote station 14 with the smallest traffic volume. Next, the information analysis unit 222 determines an addition target B for the traffic volume (step S204). The addition target B is, for example, the remote station 14 with the second smallest traffic volume. The information analysis unit 222 adds up the traffic volume of addition target A and the traffic volume of addition target B to determine a traffic volume addition value T ｔｏｔａｌ is calculated (step S205).

[0050] The information analysis unit 222 calculates the calculated traffic volume sum T ｔｏｔａｌThe information analyzer 222 compares the calculated traffic volume sum T ｔｏｔａｌ is compared with the threshold value of the remote station 14 corresponding to the addition target A.

[0051] The information analysis unit 222 calculates the traffic volume sum T ｔｏｔａｌ The information analysis unit 222 determines whether the traffic volume sum T ｔｏｔａｌ is not greater than the threshold (step S206-NO), the information analysis unit 222 adds the smallest traffic volume among the traffic volumes that have not been added, thereby obtaining a new traffic volume addition value T ｔｏｔａｌ is calculated (step S207).

[0052] Thereafter, the information analysis unit 222 executes the process of step S206 again. In this case, the information analysis unit 222 calculates the newly calculated traffic volume sum T ｔｏｔａｌ The information analysis unit 222 determines whether the traffic volume sum T ｔｏｔａｌ is greater than the threshold (step S206-YES), the information analysis unit 222 determines the distributed station 14 to which the traffic is to be aggregated (step S208). Specifically, the information analysis unit 222 determines the distributed station 14 with the largest traffic volume from among the distributed stations 14 whose traffic volumes were added up before the threshold was exceeded as the distributed station 14 to which the traffic is to be aggregated.

[0053] For example, if the distributed stations 14 having the traffic volumes added up before exceeding the threshold are the distributed stations 14-1 to 14-3, the information analysis unit 222 determines the distributed station 14 with the largest traffic volume from among the distributed stations 14-1 to 14-3 as the aggregation destination distributed station 14. Here, it is assumed that the distributed station 14-1 is determined as the aggregation destination.

[0054] Thereafter, the information analyzer 222 notifies the control unit 23 of control information including an optical path control instruction and a sleep instruction. The information analyzer 222 includes, for example, information indicating the distributed stations 14 from which the switching is to be performed (e.g., the distributed stations 14-2 and 14-3) and information indicating the distributed station 14 to which the switching is to be performed (e.g., the distributed station 14-1) in the optical path control instruction. Furthermore, the information analyzer 222 includes, for example, information indicating the distributed stations 14 to be put to sleep (e.g., the distributed stations 14-2 and 14-3) in the sleep instruction.

[0055] The optical path control unit 231 determines the distributed station 14 that will be the source of optical path switching and the distributed station 14 that will be the destination of optical path switching, based on the optical path control instructions included in the control information notified from the information analysis unit 222. Here, it is assumed that the optical path control unit 231 has determined the distributed station 14-1 as the destination of optical path switching and the distributed stations 14-2 and 14-3 as the source of optical path switching. The optical path control unit 231 transmits optical path control information including information indicating the destination distributed station and source distributed station of the determined optical path switching to the transfer device 13 (step S209).

[0056] As a result, the transfer device 13 switches the optical path route by switching the optical paths heading toward the distributed stations 14-2 and 14-3 to those heading toward the distributed station 14-1. Here, the optical path control unit 231 may transmit an optical path control instruction to the switching source distributed station of the determined optical path and the radio station 12 connected to the switching source distributed station.

[0057] The sleep control unit 232 determines which distributed stations 14 are to go to sleep based on the sleep instruction included in the control information notified by the information analysis unit 222. Here, it is assumed that the sleep control unit 232 has determined that the distributed stations 14-2 and 14-3 are to go to sleep. The sleep control unit 232 transmits a sleep instruction to the determined distributed stations 14-2 and 14-3 (step S210). This allows the distributed stations 14-2 and 14-3 to transition to a sleep state.

[0058] 4 shows a configuration in which sleep control is performed after optical path switching control is performed, but optical path switching control may be performed after sleep control is performed. Furthermore, while FIG. 4 shows a configuration in which the sleep control unit 232 puts only the remote station 14 to sleep, the sleep control unit 232 may put both the remote station 14 to sleep and the radio station 12 connected to the remote station 14 to sleep to sleep, or may put the radio station 12 to sleep.

[0059] Fig. 5 is a flowchart showing an example of the flow of sleep release processing executed by the management control device 20 in the first embodiment. The processing in Fig. 5 is executed at a timing according to the sleep control determination frequency determined in Fig. 3. Note that, here, an example will be described in which there are four remote stations 14, and traffic information is used as the cooperation information.

[0060] The information analysis unit 222 acquires the latest cooperation information for each remote station 14 stored in the information storage unit 221 (step S301). In the management control device 20, cooperation information is collected at a predetermined cycle before the processing of Fig. 5 is executed. Therefore, the information storage unit 221 accumulates cooperation information for each remote station 14 at each predetermined cycle. Therefore, when the processing of Fig. 5 is started, the information analysis unit 222 acquires the latest cooperation information for each remote station 14 at the start of the processing of Fig. 5.

[0061] Furthermore, the information analysis unit 222 may acquire the cooperation information again in accordance with the frequency of the sleep control determination. When acquiring the cooperation information again in accordance with the frequency of the sleep control determination, the information analysis unit 222 requests the information collection unit 21 to collect the cooperation information at the timing when the sleep control determination is made. The information collection unit 21 acquires the cooperation information from each remote station 14 in response to the request from the information analysis unit 222 and stores the information in the information storage unit 221. The information analysis unit 222 acquires the cooperation information stored in the information storage unit 221. This allows the information analysis unit 222 to acquire the cooperation information in accordance with the frequency of the sleep control determination.

[0062] The information analysis unit 222 calculates the traffic volume of each of the remote stations 14-1 to 14-4 based on the latest obtained cooperation information for each remote station 14 (step S302). The information analysis unit 222 compares the traffic volume of each of the remote stations 14-1 to 14-4 with a threshold. The threshold used here may be the same as or different from the threshold used in FIG. 4.

[0063] The information analysis unit 222 determines whether there is any remote station 14 whose traffic volume exceeds the threshold (step S303). If the information analysis unit 222 determines that there is no remote station 14 whose traffic volume exceeds the threshold (step S303-NO), the management control device 20 ends the processing in FIG.

[0064] On the other hand, if the information analysis unit 222 determines that there is a distributed station 14 whose traffic volume exceeds the threshold (step S303—YES), the information analysis unit 222 determines which distributed station 14 is to be woken up (step S304). Here, it is assumed that the distributed station 14 whose traffic volume exceeds the threshold is the distributed station 14-1. The information analysis unit 222 identifies the other distributed station 14 with the largest traffic volume among the sleeping distributed stations 14-2 to 14-4 among the traffic volumes aggregated at the distributed station 14-1. The following two methods can be used to identify this distributed station 14.

[0065] (Identification Method 1) Assuming that the terminal 11 will return the connection to the original remote station 14, the information analysis unit 222 first calculates the traffic volume of the terminal 11 and calculates the traffic volume of the sleeping remote station 14. The information analysis unit 222 then identifies the remote station 14 with the largest traffic volume among the calculated traffic volumes as the other remote station 14 with the largest traffic volume among the traffic volumes aggregated in the remote station 14-1.

[0066] (Identification Method 2) First, the information analysis unit 222 predicts the remote station 14 that will connect after the terminal 11 wakes up from sleep based on the location of the terminal 11. Next, the information analysis unit 222 calculates the traffic volume of the sleeping remote station 14 based on the prediction result. Then, the information analysis unit 222 identifies the remote station 14 with the largest traffic volume among the calculated traffic volumes as the other remote station 14 with the largest traffic volume among the traffic volumes aggregated to the remote station 14-1.

[0067] It is assumed that the distributed station 14-2 is identified as the other distributed station 14 with the highest traffic volume by one of the above identification methods. The information analyzer 222 determines the identified distributed station 14-2 as the distributed station 14 to be released from sleep mode. The information analyzer 222 then notifies the control unit 23 of control information including an optical path control instruction and a sleep release instruction. The information analyzer 222 includes information indicating the distributed station 14 to be switched to (e.g., the distributed station 14-2) in the optical path control instruction. Furthermore, the information analyzer 222 includes information indicating the distributed station 14 to be released from sleep mode (e.g., the distributed station 14-2) in the sleep release instruction.

[0068] The optical path control unit 231 determines the remote station 14 that will be the control target of the optical path based on the optical path control instruction included in the control information notified by the information analysis unit 222. Here, the optical path control unit 231 determines the remote station 14-2 as the control target of the optical path. The optical path control unit 231 transmits optical path control information including information indicating the remote station that will be the control target of the determined optical path to the transfer device 13 (step S305). As a result, the transfer device 13 forms an optical path toward the remote station 14-2.

[0069] The sleep control unit 232 determines the remote station 14 to be released from sleep mode based on the sleep release instruction included in the control information notified by the information analysis unit 222. Here, the sleep control unit 232 determines the remote station 14-2 as the remote station to be released from sleep mode. The sleep control unit 232 transmits the sleep release instruction to the determined remote station 14-2 (step S306). This allows the remote station 14-2 to be released from sleep mode.

[0070] Although FIG. 5 shows a configuration in which the sleep control unit 232 only wakes up the remote station 14, if the wireless station 12 is also asleep, the sleep control unit 232 may wake up the sleeping wireless station 12.

[0071] The mobile network system 100 configured as described above includes an information collection unit 21 that acquires cooperation information and flow information, and an analysis unit 22 that determines the frequency of sleep control determination based on the acquired flow information and determines whether to execute sleep control based on the cooperation information at the determined frequency. This increases the frequency of determination as to whether to execute sleep control. This increases the sleep frequency of the central station 15. This improves the power saving effect.

[0072] The analysis unit 22 determines the frequency of sleep control determination by using flow information such as timetables, traffic information, or event information so that sleep control determination is terminated at a timing that contributes to an increase or decrease in traffic. This allows the analysis unit 22 to execute sleep control at a timing when a sleep effect is expected. This increases the sleep frequency of the aggregation station 15. This makes it possible to improve the power saving effect.

[0073] (Variation 1 of the First Embodiment) In the above-described embodiment, a configuration has been shown in which the management control device 20 performs optical path control processing and sleep control processing. In contrast, a forwarding device may be configured to perform optical path control processing and sleep control processing. FIG. 6 is a diagram showing an example configuration of a mobile NW system 100a in Variation 1 of the first embodiment. The mobile NW system 100a includes a plurality of wireless stations 12-1 to 12-M, a forwarding device 13, a plurality of remote stations 14-1 to 14-N, a management control device 20a, and an external server 25.

[0074] 6, the transfer device 13 includes a control unit 23, while the management control device 20a does not include a control unit 23. The information analysis unit 222 of the management control device 20a notifies the transfer device 13 of control information. Note that the information analysis unit 222 may notify the transfer device 13 of control information only when optical path control and sleep control are performed. The control unit 23 of the transfer device 13 performs optical path control processing and sleep control processing based on the control information notified from the management control device 20a.

[0075] The control unit 23 of the transfer device 13 includes an optical path control unit 231 and a sleep control unit 232. The optical path control unit 231 performs the same processing as the optical path control unit 231 described above. The sleep control unit 232 performs the same processing as the sleep control unit 232 described above.

[0076] (Variation 2 of First Embodiment) In the above-described embodiment, a configuration has been shown in which the management control device 20 performs optical path control processing and sleep control processing. Alternatively, a configuration may be adopted in which the management control device performs sleep control processing and the forwarding device performs optical path control processing. FIG. 7 is a diagram showing an example configuration of a mobile NW system 100b in Variation 2 of the first embodiment. The mobile NW system 100b includes a plurality of radio stations 12-1 to 12-M, a forwarding device 13b, a plurality of remote stations 14-1 to 14-N, a management control device 20b, and an external server 25.

[0077] 7, the transfer device 13b includes a control unit 131. The control unit 131 includes an optical path control unit 231. The control unit 23b of the management control device 20b includes a sleep control unit 232. The information analysis unit 222 of the management control device 20b notifies the transfer device 13b of control information including information indicating the distributed station 14 that is the source of optical path switching and information indicating the distributed station 14 that is the destination of optical path switching, and notifies the control unit 23b of control information including information indicating the distributed station 14 that is the target of sleep control.

[0078] The information analysis unit 222 may notify the control information only when optical path control and sleep control are performed. The control unit 131 of the transfer device 13b performs optical path control processing based on the control information notified from the management control device 20b. The control unit 23b of the management control device 20b performs sleep control processing based on the control information notified from the information analysis unit 222. The optical path control unit 231 included in the control unit 131 of the transfer device 13b performs processing similar to that of the optical path control unit 231 described above.

[0079] (Variation 3 of First Embodiment) In the above-described embodiment, the configuration has been described in which the management control device 20 performs optical path control processing and sleep control processing. However, the optical path control processing and sleep control processing may be performed by different devices. FIG. 8 is a diagram showing an example configuration of a mobile NW system 100c in Variation 3 of the first embodiment. The mobile NW system 100c includes multiple radio stations 12-1 to 12-M, a transfer device 13, multiple remote stations 14-1 to 14-N, an external server 25, an optical transmission management control device 65, and a wireless transmission management control device 70. As shown in FIG. 8, the mobile NW system 100c includes the optical transmission management control device 65 and the wireless transmission management control device 70 instead of the management control device 20.

[0080] The optical transmission management control device 65 controls the optical transmission section. The optical transmission management control device 65 includes an information collection unit 21, an analysis unit 22, and a control unit 66. The information collection unit 21 and the analysis unit 22 perform the same processes as the information collection unit 21 and the analysis unit 22 provided in the management control device 20 described above. The control unit 66 includes an optical path control unit 231. The optical path control unit 231 performs the same processes as the optical path control unit 231 provided in the management control device 20 described above.

[0081] The wireless transmission management control device 70 controls the wireless transmission section. The wireless transmission management control device 70 includes a control unit 71. The control unit 71 includes a sleep control unit 232. The sleep control unit 232 performs the same processing as the sleep control unit 232 included in the management control device 20 described above.

[0082] The information analyzer 222 of the optical transmission management controller 65 transmits control information including information indicating the radio stations 12 and remote stations 14 that are to be subjected to sleep control to the radio transmission management controller 70. Based on the control information transmitted from the optical transmission management controller 65, the radio transmission management controller 70 causes the radio stations 12 and remote stations 14 that are to be subjected to sleep control to put into sleep mode or to cancel sleep mode.

[0083] With this configuration, different processes such as optical path switching and sleep control can be performed by a plurality of devices, thereby reducing the amount of processing performed by a single device.

[0084] (Variation 4 of the First Embodiment) In the above-described embodiment, the configuration has been described in which the management control device 20 performs optical path control processing and sleep control processing. However, the optical path control processing and sleep control processing may be performed by different devices. FIG. 9 is a diagram showing a configuration example of a mobile NW system 100d in Variation 4 of the first embodiment. The mobile NW system 100d includes multiple radio stations 12-1 to 12-M, a transfer device 13, multiple remote stations 14-1 to 14-N, an external server 25, an optical transmission management control device 65, and a wireless transmission management control device 70. As shown in FIG. 9, the mobile NW system 100d includes the optical transmission management control device 65 and the wireless transmission management control device 70 instead of the management control device 20.

[0085] The optical transmission management control device 65 shown in Fig. 9 controls the optical transmission section. The optical transmission management control device 65 shown in Fig. 9 includes a control unit 66. The control unit 66 includes an optical path control unit 231. The optical path control unit 231 performs the same processing as the optical path control unit 231 included in the management control device 20 described above.

[0086] The wireless transmission management control device 70 shown in Fig. 9 controls the wireless transmission section. The wireless transmission management control device 70 shown in Fig. 9 includes an information collection unit 21, an analysis unit 22, and a control unit 71. The information collection unit 21 and the analysis unit 22 perform the same processes as the information collection unit 21 and the analysis unit 22 provided in the management control device 20 described above. The control unit 71 includes a sleep control unit 232. The sleep control unit 232 performs the same processes as the sleep control unit 232 provided in the management control device 20 described above.

[0087] The information analyzer 222 of the wireless transmission management controller 70 transmits control information including information indicating the remote station 14 from which the optical path is switched and information indicating the remote station 14 to which the optical path is switched to, to the optical transmission management controller 65. The optical transmission management controller 65 switches the optical path based on the control information transmitted from the wireless transmission management controller 70.

[0088] With this configuration, different processes such as optical path switching and sleep control can be performed by a plurality of devices, thereby reducing the amount of processing performed by a single device.

[0089] (Fifth Modification of the First Embodiment) The mobile network system 100c shown in Fig. 8 may be configured as shown in Fig. 10. Fig. 10 is a diagram illustrating a configuration example of a mobile network system 100e in a fifth modification of the first embodiment. The mobile network system 100e includes a plurality of radio stations 12-1 to 2-M, a transfer device 13, a plurality of remote stations 14-1 to 14-N, an external server 25, an optical transmission management controller 65, a radio transmission management controller 70, and an orchestrator 75. As shown in Fig. 10, the mobile network system 100e further includes the orchestrator 75 in addition to the mobile network system 100c.

[0090] The orchestrator 75 is provided above the optical transmission management control device 65 and the wireless transmission management control device 70, and is a higher-level device that controls the optical transmission management control device 65 and the wireless transmission management control device 70. The orchestrator 75 transfers signals between the optical transmission management control device 65 and the wireless transmission management control device 70. The orchestrator 75 includes a signal transfer unit 751. The signal transfer unit 751 receives control information addressed to the wireless transmission management control device 70 and transmitted from the optical transmission management control device 65. The signal transfer unit 751 transfers the received control information to the wireless transmission management control device 70.

[0091] The optical transmission management control device 65 performs the same processing as the optical transmission management control device 65 shown in Fig. 8 except that it transmits control information addressed to the wireless transmission management control device 70 to the orchestrator 75. The wireless transmission management control device 70 performs the same processing as the wireless transmission management control device 70 shown in Fig. 8 except that it receives control information from the orchestrator 75.

[0092] (Variation 6 of the First Embodiment) The mobile NW system 100d shown in Fig. 9 may be configured as shown in Fig. 11. Fig. 11 is a diagram illustrating a configuration example of a mobile NW system 100f in Variation 6 of the first embodiment. The mobile NW system 100f includes a plurality of radio stations 12-1 to 12-M, a transfer device 13, a plurality of remote stations 14-1 to 14-N, an external server 25, an optical transmission management controller 65, a radio transmission management controller 70, and an orchestrator 75. As shown in Fig. 11, the mobile NW system 100f further includes the orchestrator 75 in addition to the mobile NW system 100d.

[0093] The orchestrator 75 is provided above the optical transmission management control device 65 and the wireless transmission management control device 70, and is a higher-level device that controls the optical transmission management control device 65 and the wireless transmission management control device 70. The orchestrator 75 transfers signals between the optical transmission management control device 65 and the wireless transmission management control device 70. The orchestrator 75 includes a signal transfer unit 751. The signal transfer unit 751 receives control information addressed to the optical transmission management control device 65 and transmitted from the wireless transmission management control device 70. The signal transfer unit 751 transfers the received control information to the optical transmission management control device 65.

[0094] The optical transmission management control device 65 performs the same processing as the optical transmission management control device 65 shown in Fig. 9 except that it receives control information from the orchestrator 75. The wireless transmission management control device 70 performs the same processing as the wireless transmission management control device 70 shown in Fig. 9 except that it transmits control information addressed to the optical transmission management control device 65 to the orchestrator 75.

[0095] (Seventh Modification of the First Embodiment) The mobile network system 100 may be configured as shown in FIG. 12 . FIG. 12 is a diagram illustrating a configuration example of a mobile network system 100g according to the seventh modification of the first embodiment. The mobile network system 100g includes a plurality of radio stations 12-1 to 12-M, a transfer device 13, a plurality of remote stations 14-1 to 14-N, an external server 25, an optical transmission management controller 65, and a wireless transmission management controller 70. As shown in FIG. 12 , the mobile network system 100g includes the optical transmission management controller 65 and the wireless transmission management controller 70 instead of the management controller 20. The mobile network system 100g is configured such that the optical transmission management controller 65 and the wireless transmission management controller 70 each receive cooperation information from each remote station 14.

[0096] The optical transmission management control device 65 shown in Fig. 12 includes an information collection unit 67, an analysis unit 68, and a control unit 66. The information collection unit 67 includes an acquisition unit 671. The acquisition unit 671 performs the same processing as the acquisition unit 211 included in the management control device 20 described above. The analysis unit 68 includes an information storage unit 681 and an information analysis unit 682. The information storage unit 681 and the information analysis unit 682 perform the same processing as the information storage unit 221 and the information analysis unit 222 included in the management control device 20 described above. The control unit 66 includes an optical path control unit 231. The optical path control unit 231 performs the same processing as the optical path control unit 231 included in the management control device 20 described above.

[0097] The wireless transmission management control device 70 includes an information collection unit 72, an analysis unit 73, and a control unit 71. The information collection unit 72 includes an acquisition unit 721. The acquisition unit 721 performs the same processing as the acquisition unit 211 included in the management control device 20 described above. The analysis unit 73 includes an information storage unit 731 and an information analysis unit 732. The information storage unit 731 and the information analysis unit 732 perform the same processing as the information storage unit 221 and the information analysis unit 222 included in the management control device 20 described above. The control unit 71 includes a sleep control unit 232. The sleep control unit 232 performs the same processing as the sleep control unit 232 included in the management control device 20 described above.

[0098] The timing at which the optical transmission management control device 65 performs the optical path control processing and the timing at which the wireless transmission management control device 70 performs the sleep control processing may be timings determined by each device. The mobile NW system 100g may include an orchestrator 75 that controls the optical transmission management control device 65 and the wireless transmission management control device 70, and the orchestrator 75 may synchronize the timing at which the optical transmission management control device 65 performs the optical path control processing and the timing at which the wireless transmission management control device 70 performs the sleep control processing.

[0099] (Variation 8 of the First Embodiment) The cooperation information may include, for example, information regarding the number of terminals 11 accommodated by each distributed station 14 (hereinafter referred to as the "number of accommodated terminals"). The cooperation information may include, for example, information regarding the processing load of the distributed station 14 (hereinafter referred to as the "processing load information"). The processing load information may be, for example, information regarding the memory usage rate of the distributed station 14 or information regarding the usage rate of the CPU (Central Processing Unit). The cooperation information may include information regarding the communication quality of the terminals 11 connected to each distributed station 14 (hereinafter referred to as the "communication quality information"). The communication quality information may be, for example, a modulation and coding scheme (MCS), a reference signal received power (RSRP), a reference signal received quality (RSRQ), a signal-to-noise ratio (SINR), packet delay, location information, etc.

[0100] When the cooperation information includes information regarding the number of accommodated terminals, the information analysis unit 222 may use the information regarding the number of accommodated terminals to select a sleep control target (for example, a sleep target or a sleep release target). In this configuration, the information analysis unit 222 may select a remote station to be subject to sleep control, in the same way as when traffic information is used.

[0101] First, the information analysis unit 222 sorts the distributed stations 14 in ascending order of the number of accommodated terminals, as specified by the information on the number of accommodated terminals. Then, the information analysis unit 222 adds up the distributed stations 14 with the fewest accommodated terminals, in ascending order of the number of accommodated terminals. The information analysis unit 222 compares the summed total with a threshold and adds up the numbers of accommodated terminals in ascending order until the threshold is exceeded. Based on the summed number of accommodated terminals before the threshold is exceeded, the information analysis unit 222 selects a sleep target from among the multiple distributed stations 14 corresponding to the summed number of accommodated terminals. Next, the information analysis unit 222 determines a distributed station to be aggregated from among the multiple distributed stations 14 corresponding to the summed number of accommodated terminals. For example, the information analysis unit 222 determines the distributed station that accommodates the most terminals 11 within the summed number of accommodated terminals within the range that does not exceed the threshold as the distributed station to be aggregated. Then, the information analysis unit 222 determines a distributed station 14 other than the aggregation target to be sleep targets from among the multiple distributed stations 14 corresponding to the summed number of accommodated terminals.

[0102] When the cooperation information includes processing load information and communication quality information, the information analysis unit 222 may select a sleep control target (e.g., a sleep target or a sleep release target) using the processing load information or communication quality information in addition to the traffic information. For example, when selecting a sleep control target using communication quality information in addition to traffic information, the information analysis unit 222 determines to perform sleep control when a condition based on the traffic information and a condition based on the communication quality information are satisfied. The condition based on the communication quality information may be, for example, a condition based on whether a path after sleep is feasible (e.g., whether quality degradation occurs). In this case, even if the information analysis unit 222 determines a sleep target and a remote station 14 to be a target of optical path control based on a condition based on traffic information, quality degradation may occur after path switching. Therefore, even if the information analysis unit 222 determines a sleep target and a remote station 14 to be a target of optical path control based on a condition based on traffic information, the information analysis unit 222 may not execute sleep if quality degradation occurs on the path after optical path control.

[0103] Second Embodiment In a second embodiment, a configuration will be described in which a base station is provided in which a wireless station, a remote station, and a central station are integrated.

[0104] (Outline of the Second Embodiment) FIG. 13 is a diagram for explaining an overview of the overall configuration and processing of a mobile network system in the second embodiment. First, the overall configuration of the mobile network system in the second embodiment will be explained. The mobile network system in the second embodiment is an example of a communication system. The mobile network system in the second embodiment is, for example, 5G. The mobile network system in the second embodiment includes a transfer device 13, multiple base stations 17-1 to 17-M, one or more servers 19, a management control device 20, and an external server 25.

[0105] Optical fibers that transmit optical signals are connected between each base station 17 and the transfer device 13, and between the transfer device 13 and the server 19. Optical fibers or electrical lines that transmit electrical signals are connected between the transfer device 13 and the management control device 20, between each base station 17 and the management control device 20, and between the management control device 20 and the external server 25.

[0106] 13 shows an example in which there are M base stations 17 and one server 19. There is no particular limit to the number of base stations 17 and servers 19. Note that although multiple transfer devices 13 may be provided, the following description will be given taking the case of one device as an example.

[0107] Each base station 17 is a device that integrates a wireless station, a remote station, and a central station. The base station 17 is equipped with one or more antennas and performs wireless communication with one or more terminals 11 located within its communication area. For example, each base station 17 transmits signals transmitted from one or more terminals 11 to the server 19 via the transfer device 13. Each base station 17 transmits signals received via the transfer device 13 to one or more terminals 11. The base station 17 transmits cooperation information to the management control device 20. The base station 17 transmits signals received via the transfer device 13 to the terminal 11.

[0108] If the base station 17 is equipped with multiple antennas, the base station 17 may perform wireless communication with one or more terminals 11 by beamforming. The base station 17 transitions to a sleep state in accordance with a sleep instruction transmitted from the management control device 20. The base station 17 releases the sleep state in accordance with a sleep release instruction transmitted from the management control device 20. The base station 17 is one aspect of a communication station.

[0109] The transfer device 13 in the second embodiment is provided between the base station 17 and the server 19. The transfer device 13 switches the optical path in accordance with optical path control information transmitted from the management control device 20. The transfer device 13 switches the connection between the base station 17 and the server 19 by switching the optical path. For example, when the transfer device 13 receives optical path control information for the optical path transmitted from the management control device 20, it executes switching so that the optical path is connected between the base station 17, which is the switching destination of the optical path, and the server 19.

[0110] The coordination information in the second embodiment includes, for example, traffic information of each base station 17. The traffic information is the same as that in the first embodiment. Furthermore, the base station 17 controls the optical path in accordance with an optical path control instruction transmitted from the management control device 20. When the base station 17 receives an optical path switching start instruction after receiving the optical path control instruction, it stops setting up the optical path between the base station 17 and the transfer device 13.

[0111] The management control device 20 in the second embodiment is a device that manages the entire mobile NW system. The management control device 20 acquires cooperation information from each base station 17. The management control device 20 uses a cooperation interface when acquiring cooperation information from each base station 17. The management control device 20 determines whether optical path control and sleep control are necessary based on the acquired cooperation information. If the management control device 20 determines that optical path control and sleep control are necessary, it performs optical path control processing and sleep control processing. The optical path control processing in the second embodiment is processing that switches optical paths between the base station 17 and the forwarding device 13 and generates optical paths. The sleep control processing in the second embodiment is processing that instructs the base station 17 that is the target of sleep control to go to sleep, or that cancels the sleep state.

[0112] Furthermore, the management control device 20 acquires the flow information from the external server 25. The management control device 20 determines the sleep control determination frequency based on the flow information. The method of determining the sleep control determination frequency is the same as in the first embodiment.

[0113] Next, an overview of the processing of the mobile network system will be explained. The upper diagram of Fig. 13 shows the connection state of the mobile network system before optical path switching, and the lower diagram of Fig. 13 shows the connection state of the mobile network system after optical path switching. The upper diagram of Fig. 13 shows an example in which terminals 11-1 and 11-2 are connected to base station 17-1, base station 17-1 is connected to server 19 via transfer device 13, terminals 11-3 and 11-4 are connected to base station 17-M, and base station 17-M is connected to server 19 via transfer device 13.

[0114] The management control device 20 determines the sleep control determination frequency based on the flow information transmitted from the external server 25. Then, the management control device 20 determines whether or not to perform optical path switching control processing in accordance with the determined sleep control determination frequency. For example, the management control device 20 determines whether or not to perform optical path switching control processing based on the latest cooperation information collected from each base station 17 at a timing according to the determined sleep control determination frequency.

[0115] The management control device 20 determines that sleep control is necessary when one base station 17 can accommodate the traffic of other base stations 17, based on the cooperation information collected from each base station 17. That is, the management control device 20 performs optical path control processing and sleep control processing when one base station 17 can accommodate the traffic of other base stations 17, based on the cooperation information collected from each base station 17. In this way, by accommodating the traffic of other base stations 17 in one base station 17, it is possible to transition the other base stations 17 that no longer have traffic to a sleep state.

[0116] When performing optical path control processing, the management control device 20 instructs the transfer device 13 to switch the optical path. The transfer device 13 switches the optical path between the transfer device 13 and the base station 17 in accordance with the instruction from the management control device 20. After completing the optical path switching, the transfer device 13 notifies the management control device 20 of the completion of the optical path switching.

[0117] When the management control device 20 receives a notification of completion of optical path switching from the transfer device 13, it transmits a sleep permission notification to the base station 17 that can transition to a sleep state. As a result, the base station 17 that can transition to a sleep state transitions to the sleep state.

[0118] The lower diagram of Figure 13 shows an example in which terminals 11-1 to 11-4 are connected to base station 17-M and base station 17-1 is transitioning to a sleep state. In this way, the mobile NW system 200 determines the frequency of sleep control determination based on flow information acquired from the external server 25. Then, based on cooperation information collected from each base station 17, the management control device 20 transitions the base station 17 that can transition to a sleep state to a sleep state by connecting the terminal 11 connected to the base station 17 that can transition to a sleep state to another base station 17 in accordance with the determined frequency. Hereinafter, the base station 17 that is the source of switching the optical path will be referred to as a switching source base station, and the base station 17 that is the destination of switching the optical path will be referred to as a switching destination base station.

[0119] (Details of the Second Embodiment) Fig. 14 is a diagram showing an example of the configuration of a mobile NW system 200 in the second embodiment. The mobile NW system 200 in the second embodiment includes a transfer device 13, multiple base stations 17-1 to 17-M, one or more servers 19, a management control device 20, and an external server 25. The transfer device 13, the base stations 17, the server 19, and the external server 25 have been described in Fig. 13, so description thereof will be omitted.

[0120] The management control device 20 includes an information collection unit 21, an analysis unit 22, and a control unit 23. The information collection unit 21 includes an acquisition unit 211. The acquisition unit 211 acquires various types of information. The acquisition unit 211 collects cooperation information from, for example, the base stations 17 at a predetermined cycle or at any timing. The acquisition unit 211 collects traffic information of each base station 17 as cooperation information. Furthermore, the acquisition unit 211 acquires flow information from an external server 25.

[0121] The analysis unit 22 includes an information storage unit 221 and an information analysis unit 222. The information storage unit 221 records the coordination information and flow information collected by the acquisition unit 211 in a predetermined storage device. The information analysis unit 222 determines the sleep control determination frequency based on the flow information recorded in the information storage unit 221. The specific determination method is the same as in the first embodiment. Furthermore, the information analysis unit 222 analyzes the state of communication between each base station 17 and the terminal 11 based on the coordination information in accordance with the determined sleep control determination frequency. Specifically, the information analysis unit 222 determines whether optical path control and sleep control are necessary based on the coordination information.

[0122] The information analysis unit 222 determines that optical path control and sleep control are necessary when any of the base stations 17 can accommodate all of the terminals 11 accommodated by one base station 17. In this case, the information analysis unit 222 notifies the control unit 23 of control information including an optical path control instruction and a sleep instruction. The optical path control instruction in the second embodiment is an instruction to request switching of the optical path, and includes, for example, information indicating the base station 17 that is the source of the optical path switching and information indicating the base station 17 that is the destination of the optical path switching. The sleep instruction in the second embodiment is an instruction to execute sleep, and includes, for example, information indicating the base station 17 that is the sleep target. The method of selecting the sleep target in the information analysis unit 222 is the same as in the first embodiment.

[0123] Furthermore, when the traffic volume of a certain base station 17 exceeds a threshold, the information analysis unit 222 determines that optical path control and sleep control are necessary. In this case, the information analysis unit 222 notifies the control unit 23 of control information including an optical path control instruction and a sleep release instruction. The sleep release instruction in the second embodiment is an instruction to execute sleep release, and includes, for example, information indicating the base station 17 to be released from sleep. The method of selecting the base station to be released from sleep in the information analysis unit 222 is the same as in the first embodiment.

[0124] The control unit 23 includes an optical path control unit 231 and a sleep control unit 232. The optical path control unit 231 determines the base station 17 that will be the source of optical path switching and the base station 17 that will be the destination of optical path switching based on the analysis results of the information analysis unit 222. For example, the optical path control unit 231 determines the base station 17 that will be the source of optical path switching based on information that indicates the base station 17 that will be the source of optical path switching, which is included in the control information notified from the information analysis unit 222. For example, the optical path control unit 231 determines the base station 17 that will be the destination of optical path switching based on information that indicates the base station 17 that will be the destination of optical path switching, which is included in the control information notified from the information analysis unit 222.

[0125] The optical path control unit 231 transmits optical path control information including information indicating the base station 17 to which the determined optical path is to be switched to, to the transfer device 13. As a result, the optical path control unit 231 instructs the transfer device 13 to switch the optical path. Furthermore, the optical path control unit 231 transmits an optical path control instruction to the base station 17 to which the determined optical path is to be switched.

[0126] Based on the analysis result of the information analysis unit 222, the sleep control unit 232 causes the base station 17 that is the target of sleep control to execute sleep or cancel sleep.

[0127] Fig. 15 is a flowchart showing an example of the flow of sleep processing executed by the management control device 20 in the second embodiment. The processing in Fig. 15 is executed at a timing according to the sleep control determination frequency determined by the information analysis unit 222. The process of determining the sleep control determination frequency in the information analysis unit 222 is the same as that in Fig. 3, and it is sufficient to read the remote station 14 in Fig. 3 as the base station 17. Note that, here, an example in which there are four base stations 17 will be described, and traffic information will be used as the cooperation information.

[0128] The information analysis unit 222 acquires the latest cooperation information for each base station 17 stored in the information storage unit 221 (step S401). In the management control device 20, cooperation information is collected at a predetermined cycle before the processing of Fig. 15 is executed. Therefore, the information storage unit 221 accumulates the cooperation information for each base station 17 at each predetermined cycle. Therefore, when the processing of Fig. 15 is started, the information analysis unit 222 acquires the latest cooperation information for each base station 17 at the start of the processing of Fig. 15.

[0129] Furthermore, the information analysis unit 222 may acquire the cooperation information again in accordance with the frequency of the sleep control determination. When acquiring the cooperation information again in accordance with the frequency of the sleep control determination, the information analysis unit 222 requests the information collection unit 21 to collect the cooperation information at the timing when the sleep control determination is made. The information collection unit 21 acquires the cooperation information from each base station 17 in response to the request from the information analysis unit 222 and stores the information in the information storage unit 221. The information analysis unit 222 acquires the cooperation information stored in the information storage unit 221. This allows the information analysis unit 222 to acquire the cooperation information in accordance with the frequency of the sleep control determination.

[0130] The information analysis unit 222 calculates the traffic volume of each of the base stations 17-1 to 17-4 based on the latest obtained cooperation information for each base station 17. Then, the information analysis unit 222 sorts the base stations 17-1 to 17-4 in ascending order of the calculated traffic volumes (step S402).

[0131] The information analysis unit 222 determines an addition target A for the traffic volume (step S403). The addition target A is, for example, the base station 17 with the smallest traffic volume. Next, the information analysis unit 222 determines an addition target B for the traffic volume (step S404). The addition target B is, for example, the base station 17 with the second smallest traffic volume. The information analysis unit 222 adds up the traffic volume of addition target A and the traffic volume of addition target B to determine a traffic volume addition value T ｔｏｔａｌ is calculated (step S405).

[0132] The information analysis unit 222 calculates the calculated traffic volume sum T ｔｏｔａｌ The information analyzer 222 compares the calculated traffic volume sum value T ｔｏｔａｌ is compared with the threshold value of the base station 17 corresponding to the addition target A.

[0133] The information analysis unit 222 calculates the traffic volume sum T ｔｏｔａｌThe information analysis unit 222 determines whether the traffic volume sum T ｔｏｔａｌ is not greater than the threshold (step S406-NO), the information analysis unit 222 adds the smallest traffic volume among the traffic volumes that have not been added, thereby obtaining a new traffic volume addition value T ｔｏｔａｌ is calculated (step S407).

[0134] Thereafter, the information analysis unit 222 executes the process of step S406 again. In this case, the information analysis unit 222 calculates the newly calculated traffic volume sum T ｔｏｔａｌ The information analysis unit 222 determines whether the traffic volume sum T ｔｏｔａｌ is greater than the threshold (step S406-YES), the information analysis unit 222 determines the base station 17 to be aggregated (step S408). Specifically, the information analysis unit 222 determines the base station 17 with the largest traffic volume from among the base stations 17 whose traffic volumes were added up before the threshold was exceeded as the base station 17 to be aggregated.

[0135] For example, if the base stations 17 having the traffic volumes added up before exceeding the threshold are base stations 17-1 to 17-3, the information analysis unit 222 may determine the base station 17 having the largest traffic volume from among the base stations 17-1 to 17-3 as the aggregation destination base station 17. Note that the method for determining the aggregation destination base station 17 is not limited to the above method and other methods may be used. Here, it is assumed that base station 17-1 is determined as the aggregation destination.

[0136] Thereafter, the information analysis unit 222 notifies the control unit 23 of control information including an optical path control instruction and a sleep instruction. The information analysis unit 222 includes, for example, information indicating the switching source base station 17 (e.g., base stations 17-2 and 17-3) and information indicating the switching destination base station 17 (e.g., base station 17-1) in the optical path control instruction. Furthermore, the information analysis unit 222 includes, for example, information indicating the base station 17 to be put to sleep (e.g., base stations 17-2 and 17-3) in the sleep instruction.

[0137] The optical path control unit 231 determines the base station 17 that will be the source of optical path switching and the base station 17 that will be the destination of optical path switching, based on the optical path control instructions included in the control information notified from the information analysis unit 222. Here, it is assumed that the optical path control unit 231 has determined base station 17-1 as the destination of optical path switching and base stations 17-2 and 17-3 as the source of optical path switching. The optical path control unit 231 transmits optical path control information including information indicating the destination base station and source base station of the determined optical path to the transfer device 13 (step S409).

[0138] As a result, the transfer device 13 switches the optical path route by switching the optical paths heading toward the base stations 17-2 and 17-3 to head toward the base station 17-1. Here, the optical path control unit 231 may transmit an optical path control instruction to the switching source base station of the determined optical path.

[0139] The sleep control unit 232 determines the base station 17 to be put to sleep based on the sleep instruction included in the control information notified from the information analysis unit 222. Here, it is assumed that the sleep control unit 232 has determined base station 17-2 and base station 17-3 as the base stations to be put to sleep. The sleep control unit 232 transmits a sleep instruction to the determined base stations 17-2 and 17-3 (step S410). This allows the sleep-target base stations 17-2 and 17-3 to transition to a sleep state.

[0140] Although FIG. 15 shows a configuration in which sleep control is performed after optical path switching control is performed, optical path switching control may be performed after sleep control is performed.

[0141] Fig. 16 is a flowchart showing an example of the flow of sleep release processing executed by the management control device 20 in the second embodiment. The processing in Fig. 16 is executed at a timing according to the sleep control determination frequency determined by the information analysis unit 222. The processing for determining the sleep control determination frequency in the information analysis unit 222 is the same as that in Fig. 3, and it is sufficient to read the remote station 14 in Fig. 3 as the base station 17. Note that, here, an example in which there are four base stations 17 will be described, and traffic information will be used as the cooperation information.

[0142] The information analysis unit 222 acquires the latest cooperation information for each base station 17 stored in the information storage unit 221 (step S501). In the management control device 20, cooperation information is collected at a predetermined cycle before the processing of Fig. 16 is executed. Therefore, the information storage unit 221 accumulates the cooperation information for each base station 17 at each predetermined cycle. Therefore, when the processing of Fig. 16 is started, the information analysis unit 222 acquires the latest cooperation information for each base station 17 at the start of the processing of Fig. 16.

[0143] Furthermore, the information analysis unit 222 may acquire the cooperation information again in accordance with the frequency of the sleep control determination. When acquiring the cooperation information again in accordance with the frequency of the sleep control determination, the information analysis unit 222 requests the information collection unit 21 to collect the cooperation information at the timing when the sleep control determination is made. The information collection unit 21 acquires the cooperation information from each base station 17 in response to the request from the information analysis unit 222 and stores the information in the information storage unit 221. The information analysis unit 222 acquires the cooperation information stored in the information storage unit 221. This allows the information analysis unit 222 to acquire the cooperation information in accordance with the frequency of the sleep control determination.

[0144] The information analysis unit 222 calculates the traffic volume of each of the base stations 17-1 to 17-4 based on the latest obtained cooperation information for each base station 17 (step S502). The information analysis unit 222 compares the traffic volume of each of the base stations 17-1 to 17-4 with a threshold. The threshold used here may be the same as or different from the threshold used in FIG. 15.

[0145] The information analysis unit 222 determines whether there is any base station 17 whose traffic volume exceeds the threshold (step S503). If the information analysis unit 222 determines that there is no base station 17 whose traffic volume exceeds the threshold (step S503-NO), the management control device 20 ends the processing in FIG. 16.

[0146] On the other hand, if the information analysis unit 222 determines that there is a base station 17 whose traffic volume exceeds the threshold (step S503—YES), the information analysis unit 222 determines the base station 17 to be the target for waking up from sleep mode (step S503). Here, it is assumed that the base station 17 whose traffic volume exceeds the threshold is base station 17-1. The information analysis unit 222 identifies, from among the sleeping base stations 17-2 to 17-4, the other base station 17 with the highest traffic volume among the traffic volumes aggregated at base station 17-1. As a method for identifying this base station, either (Identification Method 1) or (Identification Method 2) described in the first embodiment is used.

[0147] Assume that base station 17-2 is identified as the other base station 17 with the highest traffic volume by one of the above identification methods. The information analysis unit 222 determines the identified base station 17-2 as the base station 17 to be released from sleep mode. Thereafter, the information analysis unit 222 notifies the control unit 23 of control information including an optical path control instruction and a sleep release instruction. The information analysis unit 222 includes information indicating the switching destination base station 17 (e.g., base station 17-2) in the optical path control instruction. Furthermore, the information analysis unit 222 includes information indicating the base station 17 to be released from sleep mode (e.g., base station 17-2) in the sleep release instruction.

[0148] The optical path control unit 231 determines the base station 17 to be the control target of the optical path based on the optical path control instruction included in the control information notified from the information analysis unit 222. Here, the optical path control unit 231 determines the base station 17-2 as the control target of the optical path. The optical path control unit 231 transmits optical path control information including information indicating the base station 17 to be the control target of the determined optical path to the transfer device 13 (step S505). As a result, the transfer device 13 forms an optical path directed to the base station 17-2.

[0149] The sleep control unit 232 determines the base station 17 to be released from sleep mode based on the sleep release instruction included in the control information notified by the information analysis unit 222. Here, the sleep control unit 232 determines the base station 17-2 as the base station to be released from sleep mode. The sleep control unit 232 transmits the sleep release instruction to the determined base station 17-2 (step S506). This allows the base station 17-2 to be released from sleep mode.

[0150] The mobile network system 100 according to the second embodiment configured as described above includes an information collection unit 21 that acquires cooperation information and flow information, and an analysis unit 22 that determines the frequency of sleep control determination based on the acquired flow information and determines whether to execute sleep control based on the cooperation information at the determined frequency. This increases the frequency of determination as to whether to execute sleep control. This increases the sleep frequency of the base station 17. This improves the power saving effect.

[0151] (Variation 1 of the Second Embodiment) In the above-described embodiment, the configuration has been shown in which the management control device 20 performs optical path control processing and sleep control processing. In contrast, the forwarding device may be configured to perform optical path control processing and sleep control processing. In such a configuration, the mobile NW system 200 includes a forwarding device 13a shown in FIG. 6 instead of the forwarding device 13, and a management control device 20a shown in FIG. 6 instead of the management control device 20. In terms of specific processing, the radio station 12 and the remote station 14 can be read as base stations 17.

[0152] (Variation 2 of Second Embodiment) In the above-described embodiment, a configuration has been shown in which the management control device 20 performs optical path control processing and sleep control processing. Alternatively, a configuration may be adopted in which the management control device performs sleep control processing and the forwarding device performs optical path control processing. In such a configuration, the mobile NW system 200 includes a forwarding device 13b shown in FIG. 7 instead of the forwarding device 13, and a management control device 20b shown in FIG. 7 instead of the management control device 20. In terms of specific processing, the radio station 12 and the remote station 14 can be read as base stations 17.

[0153] (Variation 3 of the Second Embodiment) In the above-described embodiment, a configuration has been shown in which the management control device 20 performs optical path control processing and sleep control processing. However, the optical path control processing and sleep control processing may be performed by different devices. In such a configuration, the mobile NW system 200 includes an optical transmission management control device 65 and a wireless transmission management control device 70 shown in FIG. 8 instead of the management control device 20. For specific processing, the radio station 12 and the remote station 14 can be read as the base station 17.

[0154] (Variation 4 of the Second Embodiment) In the above-described embodiment, a configuration has been shown in which the management control device 20 performs optical path control processing and sleep control processing. However, the optical path control processing and sleep control processing may be performed by different devices. In such a configuration, the mobile NW system 200 includes an optical transmission management control device 65 and a wireless transmission management control device 70 shown in FIG. 9 instead of the management control device 20. For specific processing, the radio station 12 and the remote station 14 can be read as the base station 17.

[0155] (Fifth Modification of the Second Embodiment) The mobile NW system 200 may be configured as shown in Fig. 10. When configured in this manner, the mobile NW system 200 includes an optical transmission management control device 65, a radio transmission management control device 70, and an orchestrator 75 shown in Fig. 10 instead of the management control device 20. For specific processing, the radio station 12 and the remote station 14 can be read as the base station 17.

[0156] (Variation 6 of the Second Embodiment) The mobile NW system 200 may be configured as shown in Fig. 11. When configured in this manner, the mobile NW system 200 includes an optical transmission management control device 65, a radio transmission management control device 70, and an orchestrator 75 shown in Fig. 11 instead of the management control device 20. For specific processing, the radio station 12 and the remote station 14 can be read as the base station 17.

[0157] (Seventh Modification of the Second Embodiment) The mobile NW system 200 may be configured as shown in Fig. 12. In this configuration, the mobile NW system 200 includes an optical transmission management control device 65 and a radio transmission management control device shown in Fig. 12 instead of the management control device 20. In terms of specific processing, the radio station 12 and the remote station 14 can be read as the base station 17.

[0158] (Variation 8 of the Second Embodiment) The cooperation information may include, for example, information on the number of terminals accommodated in each base station 17. The cooperation information may include, for example, processing load information of the base station 17. The processing load information in the second embodiment may be, for example, information on memory usage rate or CPU usage rate of the base station 17. The cooperation information may include communication quality information of the terminals 11 connected to each base station 17.

[0159] When the cooperation information includes information regarding the number of accommodated terminals, the information analysis unit 222 may select a base station to be subjected to sleep control (for example, a base station to be subjected to sleep control or a base station to be subjected to sleep cancellation) using the information regarding the number of accommodated terminals. When configured in this manner, the information analysis unit 222 may select a base station to be subjected to sleep control in the same way as when traffic information is used.

[0160] First, the information analysis unit 222 sorts the base stations 17 in ascending order of the number of accommodated terminals, as specified by the information regarding the number of accommodated terminals. Then, the information analysis unit 222 adds up the base stations 17 with the fewest accommodated terminals, in ascending order of the number of accommodated terminals. The information analysis unit 222 compares the summed total with a threshold and adds up the base stations 17 with the fewest accommodated terminals until the threshold is exceeded. Based on the summed number of accommodated terminals before the threshold is exceeded, the information analysis unit 222 selects a base station 17 to be put to sleep from among the multiple base stations 17 corresponding to the summed number of accommodated terminals. Next, the information analysis unit 222 determines a base station 17 to be put to sleep from among the multiple base stations 17 corresponding to the summed number of accommodated terminals. For example, the information analysis unit 222 determines the base station 17 to be the aggregation destination, which is the base station 17 that accommodates the most terminals 11 within the summed number of accommodated terminals within the range that does not exceed the threshold. Then, the information analysis unit 222 determines a base station 17 other than the aggregation destination, as a base station 17 to be put to sleep from among the multiple base stations 17 corresponding to the summed number of accommodated terminals.

[0161] When the cooperation information includes processing load information and communication quality information, the information analysis unit 222 may select a sleep control target (e.g., a sleep target or a sleep release target) using the processing load information or communication quality information in addition to the traffic information. For example, when selecting a sleep control target using communication quality information in addition to traffic information, the information analysis unit 222 determines to perform sleep control when a condition based on the traffic information and a condition based on the communication quality information are satisfied. The condition based on the communication quality information may be, for example, a condition based on whether a path after sleep is feasible (e.g., whether quality degradation occurs). In this case, even if the information analysis unit 222 determines the base station 17 to be the sleep target and the base station 17 to be the optical path control target based on the condition based on the traffic information, quality degradation may occur after the path is switched. Therefore, even if the information analysis unit 222 determines the base station 17 to be the sleep target and the base station 17 to be the optical path control target based on the condition based on the traffic information, the information analysis unit 222 may not execute sleep if quality degradation occurs on the path after optical path control.

[0162] (Third Embodiment) In the above-described first and second embodiments, configurations for solving problems that arise in mobile network systems have been described. Specifically, in the first and second embodiments, configurations for solving a problem that arises in a mobile network system in which wireless communication is performed between a terminal and each base station, each base station autonomously determines whether or not to sleep, which may prevent overall optimization and limit the effect of power saving. However, such problems are not limited to mobile network systems, but may also arise in wired network systems in which terminals are connected by wire. Therefore, in the third embodiment, a configuration for solving the above problems that may arise in wired network systems will be described.

[0163] (Overall Configuration and Processing Overview of Wired Network System) FIG. 17 is a diagram for explaining an overview of the overall configuration and processing of a wired network system in an embodiment. First, the overall configuration of the wired network system will be described. The wired network system is an example of a communication system. The wired network system is, for example, a PON (Passive Optical Network). In the following explanation, a case where the wired network system is a PON will be explained, but the wired network system may have other configurations as long as terminals are connected by wire. For example, the wired network system may have a configuration in which terminals are connected point-to-point. The wired network system includes an external server 25, one or more ONUs 42, a transfer device 43, multiple OLTs 44, a concentrator 45, a core device 46, and a management control device 50.

[0164] Optical fibers that transmit optical signals are connected between each ONU 42 and the transfer device 43, between the transfer device 43 and each OLT 44, between each OLT 44 and the concentrator 45, and between the concentrator 45 and the core device 46. Electrical lines or optical fibers that transmit electrical signals are connected between the transfer device 43 and the management control device 50, between each OLT 44 and the management control device 50, and between the management control device 50 and the external server 25. The example shown in Figure 17 shows a case where there are four ONUs 42 and two OLTs 44. Note that multiple transfer devices 43 may be provided, but the following explanation will be given using a case where there is one.

[0165] The ONUs 42 are optical subscriber line terminals provided in user premises that terminate optical signals. One or more terminals 41 are connected to each ONU 42 via wires such as electrical lines. Each ONU 42 performs wired communication with the terminals 41. For example, each ONU 42 receives an electrical signal transmitted from the terminal 41 and converts the received electrical signal into an optical signal. Each ONU 42 transmits the converted optical signal to the OLT 44 connected thereto via a transfer device 43. Each ONU 42 receives the optical signal via the transfer device 43. Each ONU 42 converts the received optical signal into an electrical signal and transmits it to the terminal 41. The ONUs 42 are one aspect of other devices.

[0166] The transfer device 43 is provided between the ONU 42 and the OLT 44. The transfer device 43 is a switch that connects the ONU 42 and the OLT 44 via an optical path. The transfer device 43 switches the optical path in accordance with optical path control information transmitted from the management control device 50. The transfer device 43 switches the connection between the ONU 42 and the OLT 44 by switching the optical path.

[0167] The OLT 44 is an optical line termination device provided on the electric utility side and terminates optical signals. The OLT 44 receives upstream signals transmitted from one or more ONUs 42 via a transfer device 43. The OLT 44 transmits downstream signals to one or more ONUs 42 connected via the transfer device 43. The upstream signals transmitted from one or more ONUs 42 are signals obtained by converting signals transmitted from the terminal 41 into optical signals, and the downstream signals are optical signals addressed to the terminal 41. Each OLT 44 transitions to a sleep state in accordance with a sleep instruction transmitted from the management control device 50. Information acquired by the management control device 50 from the OLT 44 is called coordination information. The coordination information in the third embodiment is information indicating the state of communication between each OLT 44 and the terminal 41. The OLT 44 is one aspect of a communication station.

[0168] The cooperation information in the third embodiment includes, for example, information on the traffic volume of each remote station 14. The traffic information is the same as in the first embodiment.

[0169] The OLT 44 includes at least a transmitter, a receiver, and a sleep processor. The transmitter transmits coordination information to the management controller 50 either in response to a request from the management controller 50 or independently. The receiver receives an optical path control instruction from the management controller 50. The OLT 44 receiving an optical path control instruction from the management controller 50 indicates that the management controller 50 has determined, based on the coordination information, that it is necessary to switch the optical path between the ONU 42 and the OLT 44. The sleep processor transitions to a sleep state after switching the optical path based on the optical path control instruction. Furthermore, the OLT 44 includes an optical path switching processor for performing optical path switching processing.

[0170] The concentrator 45 aggregates the upstream signals transmitted by the OLTs 44. The concentrator 45 distributes the downstream signals.

[0171] The core device 46 performs signal processing on the upstream signals aggregated by the concentrator 45. The core device 46 transmits signals obtained as a result of the signal processing performed on the upstream signals to a server (not shown). The core device 46 transmits signals transmitted from the server (not shown) to the concentrator 45.

[0172] The core device 46 performs predetermined signal processing on the signal received from the server (not shown). The core device 46 transmits the signal obtained as a result of the signal processing performed on the signal received from the server (not shown) to the concentrator 45 as a downstream signal.

[0173] The management control device 50 is a device that manages the entire wired network system. The management control device 50 acquires coordination information from each OLT 44. When acquiring coordination information from each OLT 44, the management control device 50 uses a coordination interface. The management control device 50 determines whether optical path control and sleep control are necessary based on the acquired coordination information. If it is determined that optical path control and sleep control are necessary, the management control device 50 performs optical path control processing and sleep control processing. The optical path control processing in the third embodiment is processing that switches optical paths between the ONU 42 and the OLT 44 and generates optical paths. The sleep control processing in the third embodiment is processing that instructs the OLT 44 to go to sleep or cancels the sleep state.

[0174] Furthermore, the management control device 50 acquires the flow information from the external server 25. The management control device 50 determines the sleep control determination frequency based on the flow information. The method of determining the sleep control determination frequency is the same as in the first embodiment.

[0175] Next, an overview of the processing of the wired network system will be explained. The upper diagram of Fig. 17 shows the connection state of the wired network system before optical path switching, and the lower diagram of Fig. 17 shows the connection state of the wired network system after optical path switching. The upper diagram of Fig. 17 shows an example in which ONUs 42-1 and 42-2 are connected to OLT 44-1, and ONUs 42-3 and 42-4 are connected to OLT 44-2.

[0176] The management control device 50 determines the sleep control determination frequency based on the flow information transmitted from the external server 25. Then, the management control device 50 determines whether or not to perform optical path switching control processing in accordance with the determined sleep control determination frequency. For example, the management control device 50 determines whether or not to perform optical path switching control processing based on the latest coordination information collected from each OLT 44 at a timing according to the determined sleep control determination frequency.

[0177] The management control device 50 performs optical path control processing and sleep control processing when one OLT 44 can accommodate traffic of another OLT 44 based on the coordination information collected from each OLT 44. For example, the management control device 50 performs optical path control processing and sleep control processing in OLT 44-2 when traffic of OLT 44-1 can be accommodated. In this way, by accommodating traffic of another OLT 44 in one OLT 44, the other OLT 44 can be transitioned to a sleep state.

[0178] When the management control device 50 determines to perform optical path control processing, it instructs the transfer device 43 to switch the optical path. The transfer device 43 switches the optical path between the transfer device 43 and the OLT 44 in accordance with the instruction from the management control device 50. After completing the optical path switching, the transfer device 43 notifies the management control device 50 of the completion of the optical path switching.

[0179] When the management control device 50 receives the notification of completion of optical path switching from the transfer device 43, it transmits a sleep permission notification to the OLT 44 that can transition to the sleep state. As a result, the OLT 44 that can transition to the sleep state transitions to the sleep state.

[0180] The lower diagram of Figure 17 shows an example in which ONUs 42-1 to 42-4 are connected to OLT 44-1 and OLT 44-2 has transitioned to a sleep state. In this way, in the wired network system, the frequency of sleep control determination is determined based on the flow information acquired from the external server 25. Then, based on the linkage information collected from each OLT 44, the management control device 50 transitions the OLT 44 that can transition to a sleep state to a sleep state by connecting the terminal 41 connected to the OLT 44 that can transition to a sleep state to another OLT 44 in accordance with the determined frequency. Hereinafter, the OLT 44 that can transition to a sleep state will be referred to as a switching source OLT, and the OLT 44 that will be the new connection destination of the terminal 41 connected to the switching source OLT will be referred to as a switching destination OLT. A specific configuration will be described below.

[0181] 18 is a diagram showing an example of the configuration of a wired NW system 300 according to the third embodiment. The wired NW system 300 according to the fifth embodiment includes an external server 25, a plurality of ONUs 42-1 to 42-M, a transfer device 43, a plurality of OLTs 44-1 to 44-N, a concentrator 45, a core device 46, and a management control device 50. The external server 25, the ONUs 42, the transfer device 43, the OLT 44, the concentrator 45, and the core device 46 have been described in FIG. 17, and therefore description thereof will be omitted.

[0182] The management control device 50 includes an information collection unit 51, an analysis unit 52, and a control unit 53. The information collection unit 51 includes an acquisition unit 511. The acquisition unit 511 acquires various types of information. The acquisition unit 511 collects coordination information from, for example, the OLT 44 at a predetermined cycle or at any timing. The acquisition unit 511 collects traffic information of each OLT 44 as coordination information. Furthermore, the acquisition unit 511 acquires flow information from the external server 25.

[0183] The analysis unit 52 includes an information storage unit 521 and an information analysis unit 522. The information storage unit 521 records the coordination information and flow information collected by the acquisition unit 511 in a predetermined storage device. The information analysis unit 522 determines the sleep control determination frequency based on the flow information recorded in the information storage unit 521. The specific determination method is the same as in the first embodiment. Furthermore, the information analysis unit 522 analyzes the state of communication between each OLT 44 and the terminal 11 based on the coordination information in accordance with the determined sleep control determination frequency. Specifically, the information analysis unit 522 determines whether optical path control and sleep control are necessary based on the coordination information.

[0184] The information analysis unit 522 determines that optical path control and sleep control are necessary when all terminals 41 accommodated by one OLT 44 can be accommodated by another OLT 44. In this case, the information analysis unit 522 notifies the control unit 53 of control information including an optical path control instruction and a sleep instruction. The optical path control instruction in the third embodiment is an instruction to request switching of the optical path, and includes, for example, information indicating the OLT 44 that is the source of the optical path switching and information indicating the OLT 44 that is the destination of the optical path switching. The sleep instruction in the third embodiment is an instruction to execute sleep, and includes, for example, information indicating the OLT 44 that is the sleep target. The method of selecting the sleep target in the information analysis unit 522 is the same as in the first embodiment.

[0185] Furthermore, when the traffic volume of a certain OLT 44 exceeds a threshold, the information analysis unit 522 determines that optical path control and sleep control are necessary. In this case, the information analysis unit 522 notifies the control unit 53 of control information including an optical path control instruction and a sleep release instruction. The sleep release instruction in the third embodiment is an instruction to execute sleep release, and includes, for example, information indicating the OLT 44 to be released from sleep. The method of selecting the OLT 44 to be released from sleep in the information analysis unit 522 is the same as in the first embodiment.

[0186] The control unit 53 includes an optical path control unit 531 and a sleep control unit 532. The optical path control unit 531 determines the OLT 44 that will be the source of optical path switching and the OLT 44 that will be the destination of optical path switching based on the analysis results of the information analysis unit 522. For example, the optical path control unit 531 determines the OLT 44 that will be the source of optical path switching based on information that indicates the OLT 44 that will be the source of optical path switching, which is included in the control information notified from the information analysis unit 522. For example, the optical path control unit 531 determines the OLT 44 that will be the destination of optical path switching based on information that indicates the OLT 44 that will be the destination of optical path switching, which is included in the control information notified from the information analysis unit 522.

[0187] The optical path control unit 531 transmits optical path control information including information indicating the OLT 44 to which the determined optical path is to be switched to the transfer device 43. As a result, the optical path control unit 531 instructs the transfer device 43 to switch the optical path. Furthermore, the optical path control unit 531 transmits an optical path control instruction to the OLT 44 to which the determined optical path is to be switched.

[0188] The sleep control unit 532 causes the OLT 44 that is the target of sleep control to execute sleep or cancel sleep based on the analysis result of the information analysis unit 522 .

[0189] Fig. 19 is a flowchart showing an example of the flow of sleep processing executed by the management control device 50 in the third embodiment. The processing in Fig. 19 is executed at a timing according to the sleep control determination frequency determined by the information analysis unit 522. The processing for determining the sleep control determination frequency in the information analysis unit 522 is the same as that in Fig. 3, and the acquisition unit 211, information storage unit 221, information analysis unit 222, and remote station 14 in Fig. 3 can be read as the acquisition unit 511, information storage unit 521, information analysis unit 522, and OLT 44. Note that the following description will be given taking an example in which there are four OLTs 44, and traffic information as the linkage information.

[0190] The information analysis unit 522 acquires the latest collaboration information for each OLT 44 stored in the information storage unit 521 (step S601). In the management control device 50, collaboration information is collected at a predetermined cycle until the processing of FIG. 19 is executed. Therefore, the collaboration information for each OLT 44 is accumulated at the predetermined cycle in the information storage unit 521. Therefore, when the processing of FIG. 19 is started, the information analysis unit 522 acquires the latest collaboration information for each OLT 44 at the start of the processing of FIG. 19.

[0191] Furthermore, the information analysis unit 522 may acquire the cooperation information again in accordance with the frequency of the sleep control determination. When acquiring the cooperation information again in accordance with the frequency of the sleep control determination, the information analysis unit 522 requests the information collection unit 51 to collect the cooperation information at the timing when the sleep control determination is made. The information collection unit 51 acquires the cooperation information from each OLT 44 in response to the request from the information analysis unit 522 and accumulates the information in the information accumulation unit 521. The information analysis unit 522 acquires the cooperation information accumulated in the information accumulation unit 521. This allows the information analysis unit 522 to acquire the cooperation information in accordance with the frequency of the sleep control determination.

[0192] The information analysis unit 522 calculates the traffic volume of each of the OLTs 44-1 to 44-4 based on the latest obtained cooperation information for each OLT 44. Then, the information analysis unit 522 sorts the OLTs 44-1 to 44-4 in ascending order of the calculated traffic volumes (step S602).

[0193] The information analysis unit 522 determines an addition target A for the traffic volume (step S603). The addition target A is, for example, the OLT 44 with the smallest traffic volume. Next, the information analysis unit 522 determines an addition target B for the traffic volume (step S604). The addition target B is, for example, the OLT 44 with the second smallest traffic volume. The information analysis unit 522 adds up the traffic volume of addition target A and the traffic volume of addition target B to determine a traffic volume addition value T ｔｏｔａｌ is calculated (step S605).

[0194] The information analysis unit 522 calculates the calculated traffic volume sum T ｔｏｔａｌThe threshold value in the third embodiment is a value for control determination, and may be the same for each OLT 44, or may be a different value for each OLT 44. The threshold value may be calculated based on the cooperation information, or may be stored in advance by the information analysis unit 522 for each OLT 44. The information analysis unit 522 compares the calculated traffic volume sum value T ｔｏｔａｌ is compared with the threshold value of the OLT 44 corresponding to the addition target A.

[0195] The information analysis unit 522 calculates the traffic volume sum T ｔｏｔａｌ The information analysis unit 522 determines whether the traffic volume sum T ｔｏｔａｌ is not greater than the threshold (step S606-NO), the information analysis unit 522 adds the smallest traffic volume among the traffic volumes that have not been added, thereby obtaining a new traffic volume addition value T ｔｏｔａｌ is calculated (step S607).

[0196] Thereafter, the information analysis unit 522 executes the process of step S606 again. In this case, the information analysis unit 522 calculates the newly calculated traffic volume sum T ｔｏｔａｌ The information analysis unit 522 determines whether the traffic volume sum T ｔｏｔａｌ is greater than the threshold (step S606-YES), the information analysis unit 522 determines the OLT 44 to be the aggregation destination (step S607). Specifically, the information analysis unit 522 determines the OLT 44 with the largest traffic volume from among the OLTs 44 having the traffic volumes added up to the time when the traffic volume exceeded the threshold, as the aggregation destination OLT 44.

[0197] For example, if the OLTs 44 having the traffic volumes added up to the time before exceeding the threshold are OLTs 44-1 to 44-3, the information analysis unit 522 may determine the OLT 44 having the largest traffic volume from among the OLTs 44-1 to 44-3 as the aggregation destination OLT 44. Note that the method for determining the aggregation destination OLT 44 is not limited to the above method and other methods may also be used. Here, it is assumed that OLT 44-1 is determined as the aggregation destination.

[0198] Thereafter, the information analysis unit 522 notifies the control unit 53 of control information including an optical path control instruction and a sleep instruction. The information analysis unit 522 includes, for example, information indicating the switching source OLT 44 (e.g., OLTs 44-2 and 44-3) and information indicating the switching destination OLT 44 (e.g., OLT 44-1) in the optical path control instruction. Furthermore, the information analysis unit 522 includes, for example, information indicating the sleep target OLT 44 (e.g., OLTs 44-2 and 44-3) in the sleep instruction.

[0199] The optical path control unit 531 determines the OLT 44 that will be the source of optical path switching and the OLT 44 that will be the destination of optical path switching, based on the optical path control instruction included in the control information notified from the information analysis unit 522. Here, it is assumed that the optical path control unit 531 determines OLT 44-1 as the destination of optical path switching and OLTs 44-2 and 44-3 as the source of optical path switching. The optical path control unit 531 transmits optical path control information including information indicating the destination OLT and source OLT of the determined optical path to the transfer device 43 (step S609).

[0200] As a result, the transfer device 43 switches the optical path route by switching the optical paths heading toward the OLTs 44-2 and 44-3 to those heading toward the OLT 44-1. Here, the optical path control unit 531 may transmit an optical path control instruction to the switching source OLT of the determined optical path.

[0201] The sleep control unit 532 determines the OLT 44 to be put into sleep mode based on the sleep instruction included in the control information notified from the information analysis unit 522. Here, it is assumed that the sleep control unit 532 has determined OLT 44-2 and OLT 44-3 as the sleep targets. The sleep control unit 532 transmits a sleep instruction to the determined OLT 44-2 and OLT 44-3 (step S610). This allows the sleep-target OLT 44-2 and OLT 44-3 to transition to a sleep state.

[0202] Although FIG. 19 shows a configuration in which sleep control is performed after optical path switching control is performed, optical path switching control may be performed after sleep control is performed.

[0203] Fig. 20 is a flowchart showing an example of the flow of sleep release processing executed by the management control device 50 in the third embodiment. The processing in Fig. 20 is executed at a timing according to the sleep control determination frequency determined by the information analysis unit 522. The processing for determining the sleep control determination frequency in the information analysis unit 522 is the same as that in Fig. 3, and the acquisition unit 211, information storage unit 221, information analysis unit 222, and remote station 14 in Fig. 3 can be read as the acquisition unit 511, information storage unit 521, information analysis unit 522, and OLT 44. Note that the following description will be given taking an example in which there are four OLTs 44, and traffic information as the linkage information.

[0204] The information analysis unit 522 acquires the latest collaboration information for each OLT 44 stored in the information storage unit 521 (step S701). In the management control device 50, collaboration information is collected at a predetermined cycle until the processing of FIG. 20 is executed. Therefore, the collaboration information for each OLT 44 is accumulated at the predetermined cycle in the information storage unit 521. Therefore, when the processing of FIG. 20 is started, the information analysis unit 522 acquires the latest collaboration information for each OLT 44 at the start of the processing of FIG. 20.

[0205] Furthermore, the information analysis unit 522 may acquire the cooperation information again in accordance with the frequency of the sleep control determination. When acquiring the cooperation information again in accordance with the frequency of the sleep control determination, the information analysis unit 522 requests the information collection unit 51 to collect the cooperation information at the timing when the sleep control determination is made. The information collection unit 51 acquires the cooperation information from each OLT 44 in response to the request from the information analysis unit 522 and accumulates the information in the information accumulation unit 521. The information analysis unit 522 acquires the cooperation information accumulated in the information accumulation unit 521. This allows the information analysis unit 522 to acquire the cooperation information in accordance with the frequency of the sleep control determination.

[0206] The information analysis unit 522 calculates the traffic volume of each of the OLTs 44-1 to 44-4 based on the latest obtained cooperation information for each OLT 44 (step S702). The information analysis unit 522 compares the traffic volume of each of the OLTs 44-1 to 44-4 with a threshold. The threshold used here may be the same as or different from the threshold used in FIG. 19.

[0207] The information analysis unit 522 determines whether there is an OLT 44 whose traffic volume exceeds the threshold (step S703). If the information analysis unit 522 determines that there is no OLT 44 whose traffic volume exceeds the threshold (step S703-NO), the management control device 50 ends the processing of FIG.

[0208] On the other hand, if the information analysis unit 522 determines that there is an OLT 44 whose traffic volume exceeds the threshold (step S703—YES), the information analysis unit 522 determines the OLT 44 to be woken up (step S704). Here, it is assumed that the OLT 44 whose traffic volume exceeds the threshold is OLT 44-1. The information analysis unit 522 identifies the other OLT 44 with the largest traffic volume among the traffic volumes aggregated to OLT 44-1 from among the sleeping OLTs 44-2 to 44-4. As a method of identification, either (Identification Method 1) or (Identification Method 2) described in the first embodiment is used.

[0209] It is assumed that OLT 44-2 is identified as the other OLT 44 with the highest traffic volume by any of the above identification methods. The information analysis unit 522 determines the identified OLT 44-2 as the OLT 44 to be released from sleep mode. Thereafter, the information analysis unit 522 notifies the control unit 53 of control information including an optical path control instruction and a sleep release instruction. The information analysis unit 522 includes information indicating the OLT 44 (e.g., OLT 44-2) to be switched to in the optical path control instruction. Furthermore, the information analysis unit 522 includes information indicating the OLT 44 (e.g., OLT 44-2) to be released from sleep mode in the sleep release instruction.

[0210] The optical path control unit 531 determines the OLT 44 that will be the control target of the optical path based on the optical path control instruction included in the control information notified from the information analysis unit 522. Here, the optical path control unit 531 determines the OLT 44-2 as the control target of the optical path. The optical path control unit 531 transmits optical path control information including information indicating the OLT that will be the control target of the determined optical path to the transfer device 43 (step S705). As a result, the transfer device 43 forms an optical path toward the OLT 44-2.

[0211] The sleep control unit 532 determines the OLT 44 to be released from sleep mode based on the sleep release instruction included in the control information notified from the information analysis unit 522. Here, the sleep control unit 532 determines the OLT 44-2 as the sleep release target. The sleep control unit 532 transmits a sleep release instruction to the determined OLT 44-2 (step S706). This allows the OLT 44-2 to be released from sleep mode.

[0212] The wired network system 300 configured as described above includes an information collection unit 51 that acquires collaboration information and flow information, and an analysis unit 52 that determines the frequency at which sleep control should be performed based on the acquired flow information and determines whether or not to perform sleep control based on the collaboration information at the determined frequency. This increases the frequency at which sleep control should be performed, thereby increasing the sleep frequency of the OLT 44. This improves power saving effects.

[0213] (Variation 1 of the Third Embodiment) The collaboration information may include, for example, information on the number of terminals accommodated in each OLT 44. The collaboration information may include, for example, processing load information of the OLT 44. The processing load information in the third embodiment may be, for example, information on the memory usage rate or CPU usage rate of the OLT 44. The collaboration information may include communication quality information of the terminals 41 connected to each OLT 44.

[0214] When the cooperation information includes information regarding the number of accommodated terminals, the information analysis unit 522 may select a sleep control target (for example, a sleep target or a sleep release target) using the information regarding the number of accommodated terminals. When configured in this manner, the information analysis unit 522 may select an OLT to be a sleep control target, in the same way as when traffic information is used.

[0215] First, the information analysis unit 522 sorts the OLTs 44 in order of the number of accommodated terminals identified by the information on the number of accommodated terminals. Then, the information analysis unit 522 adds up the OLTs 44 with the fewest number of accommodated terminals in order of the number of accommodated terminals. The information analysis unit 522 compares the added total with a threshold and adds up the OLTs 44 with the fewest number of accommodated terminals in order of the number of accommodated terminals until the threshold is exceeded. The information analysis unit 522 selects a sleep target from among the multiple OLTs 44 related to the added number of accommodated terminals, based on the added number of accommodated terminals before the threshold is exceeded. Next, the information analysis unit 522 determines an OLT to be the aggregation destination from among the multiple OLTs 44 related to the added number of accommodated terminals. For example, the information analysis unit 522 determines the OLT 44 that accommodates the most terminals 41 among the added number of accommodated terminals within the range that does not exceed the threshold as the aggregation destination OLT 44. Thereafter, the information analysis unit 522 determines, from among the plurality of OLTs 44 relating to the total number of accommodated terminals, the OLTs 44 other than the aggregation destination as targets for sleep.

[0216] When the collaboration information includes processing load information and communication quality information, the information analysis unit 522 may select a sleep control target (e.g., a sleep target or a sleep release target) using the processing load information or communication quality information in addition to the traffic information. For example, when selecting a sleep control target using communication quality information in addition to traffic information, the information analysis unit 522 determines to perform sleep control when a condition based on the traffic information and a condition based on the communication quality information are satisfied. The condition based on the communication quality information may be, for example, a condition based on whether a path after sleep is feasible (e.g., whether quality degradation occurs). In this case, even if the information analysis unit 522 determines the OLT 44 to be the sleep target and the OLT 44 to be the optical path control target based on a condition based on traffic information, quality degradation may occur after the path is switched. Therefore, even if the information analysis unit 522 determines the OLT 44 to be the sleep target and the OLT 44 to be the optical path control target based on a condition based on traffic information, the information analysis unit 522 may not execute sleep if quality degradation occurs on the path after optical path control.

[0217] At least some or all of the functional units of the management control devices 20, 20a, 20b, and 50, some or all of the functional units of the transfer devices 13, 13a, 13b, and 43, and some or all of the functional units of the OLT 44 are realized as software by a processor such as a central processing unit (CPU) executing a program stored in a storage device having a non-volatile storage medium (non-transitory storage medium) and a storage unit. The program may be recorded on a computer-readable non-transitory storage medium. Examples of computer-readable non-transitory storage media include portable media such as flexible disks, magneto-optical disks, read-only memories (ROMs), and compact disc read-only memories (CD-ROMs), and storage devices such as hard disks built into computer systems.

[0218] At least some or all of the functional units of the management control devices 20, 20a, 20b, 50, some or all of the functional units of the transfer devices 13, 13a, 13b, 43, or some or all of the functional units of the OLT 44 may be realized using hardware including electronic circuits (electronic circuits or circuitry) using, for example, an LSI (Large Scale Integrated circuit), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array).

[0219] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention.

[0220] The present invention can be applied to optical communication systems such as optical access systems.

[0221] 11, 41...terminal, 12, 12-1 to 12-M...radio station, 13, 13a, 13b, 43...transfer device, 14, 14-1 to 14-N...distributed station, 15...aggregation station, 16...core device, 17, 17-1 to 17-M...base station, 19...server, 20, 20a, 20b, 50...management control device, 21...information collection unit, 22...analysis unit, 23, 23b, 66, 71, 141...control unit, 25...external server, 42, 42-1 to 42-M...ONU, 44, 44-1 to 44-N...OLT, 45...line concentrator, 46...core device, 65...optical transmission management control device, 70...wireless transmission management control device, 75...orchestrator, 211, 671, 771... Acquisition unit, 221, 681, 731... Information accumulation unit, 222, 682, 732... Information analysis unit, 231... Optical path control unit, 232... Sleep control unit, 100, 100a, 100b, 100c, 100d, 100e, 100f, 100g, 200... Mobile NW system, 300... Wired NW system, 751... Signal transfer unit

Claims

1. A control device comprising: an information collection unit that acquires coordination information regarding a plurality of communication stations connected to one or more terminals directly or via other devices, and flow information regarding the flow of the one or more terminals; and an analysis unit that determines the frequency at which sleep control decisions should be made based on the acquired flow information, and determines whether or not sleep control based on the coordination information can be executed at the determined frequency.

2. The control device according to claim 1, wherein the analysis unit determines the frequency of performing the sleep control decision using information that contributes to an increase or decrease in traffic as the flow information.

3. The control device according to claim 1 or 2, wherein the analysis unit increases the frequency when an increase or decrease in traffic is expected based on the flow information.

4. The control device according to claim 1 or 2, wherein the flow information is a transportation timetable, and the analysis unit increases the frequency in accordance with the arrival and departure times of the transportation.

5. The control device according to claim 1 or 2, wherein the flow information is traffic information, and the analysis unit increases the frequency when congestion is expected to occur or when there is no congestion.

6. The control device according to claim 1 or 2, wherein the flow information is event information, and the analysis unit increases the frequency in accordance with the start or end time of the event.

7. A control device as described in claim 1 or 2, further comprising at least one of a sleep control unit that executes sleep control on one or more communication stations that are subject to sleep control before or after optical path control is performed, or an optical path control unit that controls the optical paths of the plurality of communication stations.

8. A control method comprising: acquiring coordination information regarding multiple communication stations connected to one or more terminals directly or via other devices, and flow information regarding the flow of said one or more terminals; determining the frequency at which sleep control decisions will be made based on said acquired flow information; and determining whether or not to execute sleep control based on said coordination information at said determined frequency.

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