Communication system, management control device, and control method

Abstract

A communication system is provided with: one or more wireless stations that wirelessly communicate with one or more terminals; a plurality of distributed stations connected with the one or more wireless stations directly or via other devices; a coordination information collection unit that acquires coordination information indicating the state of communication between the plurality of distributed stations and the one or more terminals at a predetermined cycle; an optical path switching control unit that controls switching of optical paths between the one or more wireless stations and the plurality of distributed stations when it is determined, on the basis of the cooperation information, that switching of optical paths between the one or more wireless stations and the plurality of distributed stations is necessary; and a sleep control unit that, after the optical path has been switched, shifts the distributed stations capable of sleep to a sleep state.

Description

Technical Field

[0001] The invention relates to a communication system, a management control device and a control method. Background Art

[0002] In a conventional communication system in which wireless communication is performed between a terminal and each base station, each base station calculates the throughput and autonomously goes into sleep mode when the throughput exceeds a threshold, thereby achieving power saving. In such a communication system, a terminal connected to a sleep base station is instructed to switch to a base station with the highest throughput, so that the terminal can continue to communicate.

[0003] Prior art literature Non-patent literature Non-patent literature 1: Yong Sheng Soh, Tony QS Quek, and Marios Kountouris, “Dynamic Sleep Mode Strategies in Energy Efficient Cellular Networks”, IEEE, Communications Theory, pp. 31313136, June 2013. Summary of the invention

[0004] Problems to be solved by the invention However, in the previous communication system, the terminal connected to the dormant base station switches to a base station that has been connected to multiple terminals, which may lead to deterioration of communication quality. In addition, in the previous communication system, since each base station independently determines whether to sleep, it is not possible to optimize the whole system, and the effect of power saving may be limited.

[0005] In view of the above circumstances, an object of the present invention is to provide a technology capable of increasing the power saving effect without deteriorating the communication quality.

[0006] Solutions to Solve Problems One embodiment of the present invention is a communication system, which comprises: one or more wireless stations for wirelessly communicating with one or more terminals; multiple distribution stations connected to the one or more wireless stations directly or via other devices; a collaboration information collection unit for acquiring collaboration information at a prescribed period, the collaboration information indicating the status of communication between the multiple distribution stations and the one or more terminals; an optical path switching control unit for controlling the switching of optical paths between the one or more wireless stations and the multiple distribution stations when it is determined based on the collaboration information that the switching of optical paths between the one or more wireless stations and the multiple distribution stations is necessary; and a sleep control unit for causing the sleep-capable distribution stations to transition to a sleep state after the optical paths are switched.

[0007] One embodiment of the present invention is a management control device, which comprises: a collaboration information collection unit, which obtains collaboration information at a prescribed period, wherein the collaboration information shows the status of communication between multiple distribution stations and one or more terminals, wherein the multiple distribution stations are connected to one or more wireless stations directly or via other devices, and the one or more wireless stations communicate wirelessly with the one or more terminals; an analysis unit, which determines whether switching of optical paths and sleep control between the one or more wireless stations and the multiple distribution stations are required based on the collaboration information; an optical path switching control unit, which controls switching of optical paths between the one or more wireless stations and the multiple distribution stations when it is determined that switching of optical paths between the one or more wireless stations and the multiple distribution stations is required; and a sleep control unit, which causes the distribution stations that can sleep to transition to a sleep state after switching the optical paths.

[0008] One embodiment of the present invention is a control method, wherein cooperation information is obtained at a prescribed period, the cooperation information indicating the state of communication between a plurality of distribution stations and one or more terminals, the plurality of distribution stations are connected to one or more wireless stations directly or via other devices, and the one or more wireless stations communicate wirelessly with the one or more terminals; when it is determined based on the cooperation information that switching of optical paths between the one or more wireless stations and the plurality of distribution stations is required, switching of optical paths between the one or more wireless stations and the plurality of distribution stations is controlled; after switching of the optical paths, distribution stations that are capable of sleep are transferred to a sleep state.

[0009] Effects of the Invention According to the present invention, it is possible to increase the power saving effect without deteriorating the communication quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a diagram for explaining the overall configuration and processing overview of the mobile NW system of the present invention. Figure 2 It is a diagram showing a configuration example of the mobile NW system according to the first embodiment. Figure 3 This is a flowchart showing an example of the flow of the sleep process executed by the management control device according to the first embodiment. Figure 4 This is a flowchart showing an example of the flow of the sleep process executed by the management control device according to the first embodiment. Figure 5 This is a sequence diagram showing an example of a detailed flow of the sleep process executed by the mobile NW system according to the first embodiment. Figure 6This is a flowchart showing an example of the flow of the sleep release process executed by the management control device according to the first embodiment. Figure 7 This is a sequence diagram showing an example of a detailed flow of the sleep release process executed by the mobile NW system according to the first embodiment. Figure 8 It is a diagram showing a configuration example of a mobile NW system according to a modification example of the first embodiment. Fig. 9 It is a diagram showing a configuration example of a mobile NW system according to a modification of the first embodiment. Fig.10 This is a sequence diagram showing an example of a detailed flow of a sleep process executed by the mobile NW system according to a modification of the first embodiment. Fig.11 This is a sequence diagram showing an example of a detailed flow of a sleep release process executed by the mobile NW system according to the modification of the first embodiment. Fig.12 It is a diagram showing a configuration example of a mobile NW system according to the second embodiment. Fig.13 This is a flowchart showing an example of the flow of the sleep process executed by the management control device according to the second embodiment. Fig.14 This is a flowchart showing an example of the flow of the sleep process executed by the management control device according to the second embodiment. Fig.15 This is a sequence diagram showing an example of a detailed flow of the sleep process executed by the mobile NW system according to the second embodiment. Fig.16 This is a flowchart showing an example of the flow of the sleep release process executed by the management control device according to the second embodiment. Fig.17 This is a sequence diagram showing an example of a detailed flow of the sleep release process executed by the mobile NW system according to the second embodiment. Fig.18 This is a sequence diagram showing an example of a detailed flow of the sleep process executed by the mobile NW system according to the modification example of the second embodiment. Fig.19 This is a sequence diagram showing an example of a detailed flow of a sleep release process executed by the mobile NW system according to the modification of the second embodiment. Fig. 20 This is a flowchart showing an example of the flow of the sleep process executed by the management control device according to the third embodiment. Fig.21 This is a flowchart showing an example of the flow of the sleep process executed by the management control device according to the third embodiment. Fig. 22This is a sequence diagram showing an example of a detailed flow of the sleep process executed by the mobile NW system according to the third embodiment. Fig.23 This is a flowchart showing an example of the flow of the sleep release process executed by the management control device according to the third embodiment. Fig.24 This is a sequence diagram showing an example of a detailed flow of the sleep release process executed by the mobile NW system according to the third embodiment. Fig.25 This is a sequence diagram showing an example of a detailed flow of a sleep process executed by the mobile NW system according to a modification of the third embodiment. Fig.26 This is a sequence diagram showing an example of a detailed flow of a sleep release process executed by the mobile NW system according to a modification of the third embodiment. Fig. 27 It is a diagram showing a configuration example of a mobile NW system according to a fourth embodiment. Fig.28 This is a flowchart showing an example of the flow of the sleep process executed by the management control device according to the fourth embodiment. Fig.29 This is a flowchart showing an example of the flow of the sleep process executed by the management control device according to the fourth embodiment. Fig.30 This is a sequence diagram showing an example of a detailed flow of the sleep process executed by the mobile NW system according to the fourth embodiment. Fig.31 This is a flowchart showing an example of the flow of the sleep release process executed by the management control device according to the fourth embodiment. Fig.32 This is a sequence diagram showing an example of a detailed flow of a sleep release process executed by the mobile NW system according to the fourth embodiment. Fig.33 This is a sequence diagram showing an example of a detailed flow of a sleep process executed by the mobile NW system according to a modification of the fourth embodiment. Fig.34 This is a sequence diagram showing an example of a detailed flow of a sleep release process executed by the mobile NW system according to a modification of the fourth embodiment. DETAILED DESCRIPTION

[0011] Hereinafter, one embodiment of the present invention will be described with reference to the drawings. (Overview of overall structure and processing) Figure 1This is a diagram for explaining the overall structure and processing overview of the mobile NW system of the present invention. First, the overall structure of the mobile NW system is described. The mobile NW system is an example of a communication system. The mobile NW system is, for example, a fifth-generation mobile communication system (hereinafter referred to as "5G"). The mobile NW system includes one or more wireless stations 12, a switching device 13, a plurality of distribution stations 14, a collection station 15, a core device 16, and a management control device 20.

[0012] The wireless station 12 and the switching device 13, the switching device 13 and the distribution station 14, the distribution station 14 and the collection station 15, and the collection station 15 and the core device 16 are connected by optical fibers for transmitting optical signals. The switching device 13 and the management control device 20, and the distribution station 14 and the management control device 20 are connected by wires or optical fibers for transmitting electrical signals. Figure 1 In the example shown, there are four wireless stations 12 and two distribution stations 14. In addition, a plurality of switching devices 13 may be provided, but in the following description, a case where only one switching device is provided will be described as an example.

[0013] Each wireless station 12 has one or more antennas and performs wireless communication with the terminal 11. For example, each wireless station 12 receives a signal sent from the terminal 11 and sends the received signal to the distribution station 14 connected via the switching device 13. Each wireless station 12 sends the signal received via the switching device 13 to the terminal 11. The wireless station 12 is, for example, an RU (Radio Unit) in the 5G communication standard.

[0014] The switch 13 is provided between the wireless station 12 and the distribution station 14. The switch 13 switches the optical path according to the instruction from the management control device 20. The optical path is the path of the optical signal. The switch 13 switches the connection between the wireless station 12 and the distribution station 14 by switching the optical path.

[0015] The distribution station 14 receives an uplink signal sent by the wireless station 12 via the switching device 13. The distribution station 14 sends a downlink signal to the wireless station 12 via the switching device 13. In addition, the uplink signal is a signal sent by the terminal 11, and the downlink signal is a signal destined for the terminal 11. Each distribution station 14 transitions to a sleep state according to an instruction from the management control device 20. The sleep state is a state in which power saving can be achieved by stopping some functions. The distribution station 14 is, for example, a DU (Distributed Unit) in the 5G communication standard. The information obtained by the management control device 20 from the distribution station 14 is called collaboration information. Collaboration information is information showing the communication status between each distribution station 14 and the terminal 11.

[0016] The collaboration information includes, for example, information related to the number of terminals 11 accommodated by each distribution station 14 (hereinafter referred to as the "accommodated terminal number"). The collaboration information includes, for example, the maximum number of terminals accommodated by the distribution station 14. The maximum number of terminals accommodated by the distribution station 14 refers to the maximum number that the distribution station 14 can accommodate. The collaboration information includes, for example, information about the wireless stations 12 connected to the distribution station 14 of the optical path (hereinafter referred to as the "connected wireless station information"). The collaboration information includes, for example, information related to the processing load of the distribution station 14 (hereinafter referred to as the "processing load information"). The processing load information may also be, for example, information about the usage rate of the memory of the distribution station 14 or information about the usage rate of the CPU (Central Processing Unit). The collaboration information includes, for example, information related to the processing delay of each distribution station 14 (hereinafter referred to as the "processing delay information"). The collaboration information includes, for example, information related to the transmission delay between the terminal 11 and each distribution station 14 (hereinafter referred to as the "delay information").

[0017] The aggregation station 15 aggregates the uplink signals sent by the distribution stations 14. The aggregation station 15 distributes the downlink signals. The aggregation station 15 is, for example, a CU (Centralized Unit) in the 5G communication standard.

[0018] The core device 16 performs signal processing on the uplink signal aggregated by the aggregation station 15. The core device 16 transmits a signal obtained as a result of performing the signal processing on the uplink signal to the external network. The core device 16 receives a signal from the external network.

[0019] The core device 16 performs predetermined signal processing on the signal received from the external network. The core device 16 transmits the signal obtained as a result of performing signal processing on the signal received from the external network as a downlink signal to the aggregation station 15. The signal processing is, for example, the transfer of user data in the UPF (User Plane Function) of the 5G core network.

[0020] The management control device 20 obtains the cooperation information from the distribution station 14. The management control device 20 determines whether the switching of the optical path and the sleep control are required based on the obtained cooperation information. When the management control device 20 determines that the switching of the optical path and the sleep control are required, it performs the switching control process of the optical path and the sleep control process. The switching control process of the optical path is a process of switching the optical path between the wireless station 12 and the distribution station 14. For example, the management control device 20 instructs the switching device 13 to control the switching of the optical path between the wireless station 12 and the distribution station 14. The sleep control process is a process of executing the sleep or releasing the sleep for the distribution station 14.

[0021] Next, an overview of the processing of the mobile NW system will be described. Figure 1 The figure above shows the connection status of the mobile NW system before the optical path switching. Figure 1 The following figure shows the connection status of the mobile NW system after the optical path is switched. Figure 1 In the above figure, an example is shown in which the wireless stations 12-1 and 12-2 are connected to the distribution station 14-1 and the wireless stations 12-3 and 12-4 are connected to the distribution station 14-2.

[0022] The management control device 20 determines whether to perform the optical path switching control process based on the cooperation information collected from each distribution station 14. The management control device 20 determines to perform the optical path switching control process when there is a distribution station 14 that can be transferred to the sleep state. The distribution station 14 that can be transferred to the sleep state is, for example, a distribution station 14 that does not accommodate the terminal 11.

[0023] On the other hand, when there is no distribution station 14 that can be transferred to the sleep state, the management control device 20 determines not to perform the switching control process of the optical path. When the management control device 20 determines to perform the switching control process of the optical path, it instructs the switching device 13 to switch the optical path. The switching device 13 switches the optical path between the wireless station 12 and the distribution station 14 according to the instruction from the management control device 20. After the switching of the optical path is completed, the switching device 13 notifies the management control device 20 of the completion of the switching of the optical path.

[0024] When receiving the notification of completion of optical path switching from the switching device 13, the management control device 20 sends a sleep permission notification to the distribution station 14 that can be transferred to the sleep state. The sleep permission notification is a signal including an instruction for transferring the distribution station 14 to the sleep state. As a result, the distribution station 14 that can be transferred to the sleep state transfers to the sleep state.

[0025] exist Figure 1 The following figure shows an example in which wireless stations 12-1 to 12-4 are connected to distribution station 14-1 and distribution station 14-2 is transferred to the sleep state. In this way, in the mobile NW system 100, based on the cooperation information collected from each distribution station 14, the terminal 11 connected to the distribution station 14 that can transfer to the sleep state is connected to another distribution station 14, thereby transferring the distribution station 14 that can transfer to the sleep state to the sleep state. Hereinafter, the distribution station 14 that can transfer to the sleep state is described as a switching source distribution station, and the distribution station 14 that will become the new connection destination of the terminal 11 connected to the switching source distribution station is described as a switching destination distribution station.

[0026] (First Embodiment) Figure 21 is a diagram showing a configuration example of a mobile NW system 100 according to the first embodiment. The mobile NW system 100 according to the first embodiment includes one or more wireless stations 12, a switching device 13, a plurality of distribution stations 14, a collection station 15, a core device 16, and a management control device 20. The wireless stations 12, the switching devices 13, the distribution stations 14, the collection station 15, and the core device 16 are configured as follows: Figure 1 The management control device 20 includes a coordination information collecting unit 21 , an analyzing unit 22 , and a control unit 23 .

[0027] The coordination information collecting unit 21 includes an acquiring unit 211. The acquiring unit 211 collects coordination information from the distribution stations 14 at a predetermined period.

[0028] The analysis unit 22 includes a coordination information accumulation unit 221 and a real-time analysis unit 222. The coordination information accumulation unit 221 records the collected coordination information in a predetermined storage device. The real-time analysis unit 222 analyzes the communication status between each distribution station 14 and the terminal 11, such as the change in the number of connections of the distribution station 14 per unit time, based on the coordination information. Specifically, the real-time analysis unit 222 determines whether the switching of the optical path and the sleep control are required based on the coordination information.

[0029] For example, the real-time analysis unit 222 determines that the switching of the optical path and the sleep control are necessary when all the terminals 11 accommodated in the switching source distribution station can be accommodated in other distribution stations 14. In this case, the real-time analysis unit 222 notifies the control unit 23 of information indicating the distribution station 14 that is the switching destination of the optical path and information indicating the distribution station 14 that is the sleep target.

[0030] For example, when the number of terminals 11 accommodated in the distribution station 14 exceeds the maximum number of accommodated terminals, the real-time analysis unit 222 determines that the switching of the optical path and the sleep control are necessary. In this case, the real-time analysis unit 222 notifies the control unit 23 of information indicating the distribution station 14 to be the switching destination of the optical path and information indicating the distribution station 14 to be the object of sleep release.

[0031] The control unit 23 includes an optical path switching control unit 231 and a sleep control unit 232. The optical path switching control unit 231 determines the distribution station 14 to be the switching destination of the optical path based on the analysis result of the real-time analysis unit 322, and instructs the switching device 13 to switch the optical path. For example, the optical path switching control unit 231 determines the distribution station 14 to be the switching destination of the optical path based on the information indicating the distribution station 14 to be the switching destination of the optical path notified from the real-time analysis unit 222.

[0032] The sleep control unit 232 causes the distributed station 14 to execute sleep or cancel sleep based on the analysis result of the real-time analysis unit 322 .

[0033] Figure 3 1 is a flowchart showing an example of the process of the sleep process executed by the management control device 20 of the first embodiment. Figure 3 In the description, the case where the cooperation information includes at least the information on the number of accommodated terminals of each distribution station 14 and the information on the maximum number of accommodated terminals is taken as an example. Figure 3 The processing flow is repeated at a specified cycle.

[0034] The acquisition unit 211 acquires the cooperation information from each distribution station 14 (step S101). The acquisition unit 211 accumulates the obtained cooperation information of each distribution station 14 in the cooperation information accumulation unit 221 (step S102). The real-time analysis unit 222 calculates the number of terminals that can be additionally accommodated in each distribution station 14 based on the cooperation information of each distribution station 14 accumulated in the cooperation information accumulation unit 221 (step S103). Here, the number of terminals that can be additionally accommodated means the number of terminals 11 that can be additionally accommodated in addition to the number of terminals currently accommodated in the distribution station 14. For example, the number of terminals that can be additionally accommodated is obtained by subtracting the number of accommodated terminals from the maximum number of accommodated terminals.

[0035] The real-time analysis unit 222 determines whether the first switching condition is satisfied (step S104). The first switching condition is a condition indicating the need to switch the optical path between the wireless station 12 and the distribution station 14, for example, the number of additional accommodating terminals of a certain distribution station 14 is greater than the number of accommodating terminals of the distribution station 14 that is the subject of the sleep judgment.

[0036] When the real-time analysis unit 222 determines that the first switching condition is satisfied (step S104 is "yes"), it notifies the control unit 23 of the switching instruction of the optical path and the instruction of the sleep control. The optical path switching control unit 231 instructs the switching device 13 to switch the optical path of the wireless station 12 connected to the switching source distribution station based on the switching instruction of the optical path notified from the real-time analysis unit 222 (step S105). Specifically, the optical path switching control unit 231 instructs so that the optical path of the wireless station 12 connected to the switching source distribution station is directed to the switching destination distribution station.

[0037] The sleep control unit 232 sends a sleep permission notification to the switching source distribution station (step S106). For example, the sleep control unit 232 may send a sleep instruction to the switching source distribution station when receiving an optical path switching completion notification from the wireless station 12 connected to the switching source distribution station and the switching destination distribution station. The optical path switching completion notification is a signal including content indicating that the switching of the optical path is completed. As a result, the switching source distribution station can transition to the sleep state.

[0038] In the process of step S104, when the real-time analysis unit 222 determines that the first switching condition is not satisfied (step S104 is "No"), it determines whether there are other distribution stations 14 (step S107). Other distribution stations 14 refer to distribution stations 14 that are not compared with the distribution stations 14 that are the target of sleep determination, for example. When the real-time analysis unit 222 determines that there are no other distribution stations 14 (step S107 is "No"), the process ends.

[0039] On the other hand, when the real-time analysis unit 222 determines that there are other distribution stations 14 ("Yes" in step S107), it selects the information of the number of additionally accommodating terminals of the other distribution stations 14 (step S108). The real-time analysis unit 222 uses the information of the number of additionally accommodating terminals of the selected other distribution stations 14 to execute the process of step S104 again.

[0040] Figure 4 : is a flowchart showing an example of the process of the sleep process executed by the management control device 20 of the first embodiment. Figure 4 The processing illustrated in the figure more specifically shows Figure 3 The content of the processing is shown.

[0041] The acquisition unit 211 acquires the maximum number of accommodated terminals, connected wireless station information, and information on the number of accommodated terminals of each distribution station from each distribution station 14 as coordination information (step S201).

[0042] The acquisition unit 211 accumulates the acquired cooperation information of each distribution station 14 in the cooperation information accumulation unit 221 (step S202). The real-time analysis unit 222 calculates the number of terminals that can be additionally accommodated in each distribution station 14 based on the cooperation information of each distribution station 14 accumulated in the cooperation information accumulation unit 221 (step S203). Next, the real-time analysis unit 222 substitutes a value of 1 into the constant i (step S204). i represents, for example, the distribution station 14-i that becomes the switching destination. When i=1, the distribution station 14-1 becomes the switching destination distribution station. i is a value of 1≤i≤I. I is the total number of distribution stations 14.

[0043] Next, the real-time analysis unit 222 substitutes the value of (i+1) into k (step S205). k represents, for example, the distribution station 14-k that becomes the switching source. In the case of k=2 (i=1), the distribution station 14-2 becomes the switching source distribution station. k is a value of 2≤k≤K. K is the total number of distribution stations 14-1, that is, K=(I-1).

[0044] Then, the real-time analysis unit 222 determines whether U i -u i >u k (Step S206).i represents the maximum number of terminals that can be accommodated by the distribution station 14-i, u i represents the number of terminals accommodated by the distribution station 14-i, u k Indicates the number of terminals accommodated by the distribution station 14-k. i -u i >u k The conditions shown are specific examples of the first switching conditions. As an example, it is assumed that the maximum number of terminals accommodated by the distribution station 14-1 is 1000, the number of terminals accommodated by the distribution station 14-1 is 100, the maximum number of terminals accommodated by the distribution station 14-2 is 800, and the number of terminals accommodated by the distribution station 14-2 is 200.

[0045] When i=1 and k=2, it is expressed as follows: ·

[0046] According to the above results, U1-u1>u2 is 900>200, which satisfies the first switching condition. i -u i >u k ) (step S206 is "Yes"), the control unit 23 is notified of the switching instruction of the optical path and the instruction of the sleep control.

[0047] The optical path switching control unit 231 instructs the switching device 13 to switch the optical path of the wireless station 12 connected to the distribution station 14-k based on the switching instruction of the optical path notified from the real-time analysis unit 222 (step S207). Specifically, the optical path switching control unit 231 instructs the switching device 13 to switch the optical path of the wireless station 12 connected to the distribution station 14-k (for example, the distribution station 14-2) to the distribution station 14-i (for example, the distribution station 14-1). The sleep control unit 232 sends a sleep permission notification to the distribution station 14-k (for example, the distribution station 14-2) (step S208).

[0048] On the other hand, as an example, consider the case where the maximum number of terminals accommodated by the distribution station 14-1 is 1000, the number of terminals accommodated by the distribution station 14-1 is 500, the maximum number of terminals accommodated by the distribution station 14-2 is 800, and the number of terminals accommodated by the distribution station 14-2 is 700. When i=1 and k=2, it is expressed as follows: ·

[0049] According to the above results, U1-u1>u2 is 500<700, which does not meet the first switching condition. i -u i >u k) (step S206 is "No"), determine whether k is the maximum value (step S209).

[0050] When the real-time analysis unit 222 determines that k is not the maximum value (step S209 is "No"), it adds 1 to the value of k (step S210). Thereafter, the real-time analysis unit 222 performs the processing of step S206 again. For example, as in the above example, when i=1, k=2 and k is not the maximum value, the real-time analysis unit 222 adds 1 to the value of k, and becomes k=3. Then, the real-time analysis unit 222 determines whether U1-u1>u3 is satisfied.

[0051] On the other hand, when the real-time analysis unit 222 determines that k is the maximum value (step S209: Yes), it determines whether i is the maximum value (step S211). When the real-time analysis unit 222 determines that i is the maximum value (step S211: Yes), it ends the process.

[0052] On the other hand, when the real-time analysis unit 222 determines that i is not the maximum value (step S211 is "No"), it adds 1 to the value of i (step S212). Then, the real-time analysis unit 222 performs the processing of step S205 again. For example, when i=1, k=3, k is the maximum value and i is not the maximum value, the real-time analysis unit 222 adds 1 to the value of i, and it becomes i=2.

[0053] Then, the real-time analysis unit 222 substitutes the value of (i+1) into k in the process of step S205 (step S205). In this case, i=2 and k=3. Then, the real-time analysis unit 222 determines whether U2-u2>u3 is satisfied in the process of step S206.

[0054] Figure 5 is a sequence diagram showing an example of a detailed flow of the sleep process performed by the mobile NW system 100 according to the first embodiment. Figure 5 In the description, it is assumed that the distribution station 14-1 is the switching destination distribution station and the distribution station 14-2 is the switching source distribution station. Here, the description is given as the switching destination distribution station 14-1 and the switching source distribution station 14-2.

[0055] The acquisition unit 211 of the management control device 20 acquires the coordination information from the switching destination distribution station 14-1 and the switching source distribution station 14-2 at a predetermined period (step S301, step S302). The acquisition unit 211 accumulates the acquired coordination information in the coordination information accumulation unit 221. When the coordination information is accumulated in the coordination information accumulation unit 221, the real-time analysis unit 222 performs switching of the optical path and sleep control judgment (step S303).

[0056] The switching of the optical path and the sleep control judgment in step S303 is a judgment of whether the first switching condition in step S104 is satisfied. Here, it is assumed that the first switching condition in step S104 is satisfied. When the first switching condition is satisfied, the real-time analysis unit 222 instructs the optical path switching control unit 231 to perform the switching control of the optical path, and instructs the sleep control unit 232 to perform the sleep control.

[0057] The optical path switching control unit 231 notifies the switching device 13 and the aggregation station 15 of the optical path switching destination information (step S304). The optical path switching destination information is information related to the switching destination of the optical path. Figure 5 In the example shown, the optical path switching destination information includes information indicating that the switching destination distribution station 14-1 is the switching destination of the optical path. When the optical path switching destination information is notified from the management control device 20, the switching device 13 instructs the wireless station 12 connected to the switching source distribution station 14-2, the switching destination distribution station 14-1, and the switching source distribution station 14-2 to switch the optical path (step S305). For example, the switching device 13 instructs the wireless station 12 connected to the switching source distribution station 14-2 to switch the optical path to the switching destination distribution station 14-1, instructs the switching destination distribution station 14-1 to switch so that the wireless station 12 connected to the switching source distribution station 14-2 is connected to the optical path, and instructs the switching source distribution station 14-2 not to set the optical path.

[0058] The wireless station 12 connected to the switching source distribution station 14-2, the switching destination distribution station 14-1, and the switching source distribution station 14-2 prepare for the switching of the optical path (steps S306, S307, and S308). The wireless station 12 connected to the switching source distribution station 14-2, the switching destination distribution station 14-1, and the switching source distribution station 14-2 send an optical path switching response notification to the switching device 13 (steps S309, S310, and S311). The optical path switching response notification is a signal including content indicating that the optical path switching destination information has been received.

[0059] When the switching device 13 receives the optical path switching response notification from the wireless station 12 connected to the switching source distribution station 14-2, the switching destination distribution station 14-1, and the switching source distribution station 14-2, the switching device 13 sends an optical path switching start notification to the wireless station 12 connected to the switching source distribution station 14-2 and the switching destination distribution station 14-1 (step S312). The optical path switching start notification is a signal including a command to start switching of the optical path.

[0060] The wireless station 12 connected to the switching source distribution station 14-2 and the switching destination distribution station 14-1 switch the optical path in response to the reception of the optical path switching start notification (step S313, step S314). Through this process, the optical path of the wireless station 12 connected to the switching source distribution station 14-2 is switched toward the switching destination distribution station 14-1. That is, the wireless station 12 and the switching destination distribution station 14-1 become in a state where they can communicate.

[0061] The switching destination distribution station 14-1 transmits a path switching request to the core device 16 (step S315). The path switching request is a signal including content requesting switching of the communication path in the core device 16. In response to receiving the path switching request, the core device 16 switches the path (step S316).

[0062] When the path switching is completed, the core device 16 transmits a path switching response notification to the switching destination distribution station 14-1 (step S317). The path switching response notification is a signal including content showing that the switching of the communication path in the core device 16 is completed.

[0063] When the optical path switching is completed, the wireless station 12 sends an optical path switching completion notification to the management control device 20 (step S318). The optical path switching completion notification is a signal including content indicating that the switching of the optical path is completed. When the switching of the optical path is completed, the switching destination distribution station 14-1 sends an optical path switching completion notification to the management control device 20 (step S319).

[0064] When the sleep control unit 232 receives the optical path switching completion notification from the destination of the optical path switching start notification, it sends a sleep permission notification to the switching source distribution station 14-2 (step S320). When the switching source distribution station 14-2 receives the sleep permission notification from the management control device 20, it sends a sleep response notification to the management control device 20 (step S321). The sleep response notification is a signal including content indicating that the sleep permission notification has been received. After sending the sleep response notification, the switching source distribution station 14-2 transitions to the sleep state (step S322).

[0065] Figure 6 4 is a flowchart showing an example of the process of the sleep release process executed by the management control device 20 of the first embodiment. The acquisition unit 211 acquires the number of accommodated terminals and the information of the dormant distributed station 14-k from each distributed station 14 as the cooperation information (step S401). The acquisition unit 211 notifies the analysis unit 22 of the acquired information of the number of accommodated terminals and the dormant distributed station 14-k.

[0066] The real-time analysis unit 222 reads the information of the maximum number of terminals accommodated in each distribution station 14 and the information of the wireless station 12 connected to the dormant distribution station 14-k from the cooperation information accumulation unit 221 (step S402). The real-time analysis unit 222 calculates the number of additionally accommodable terminals in each distribution station 14 based on the cooperation information of each distribution station 14 accumulated in the cooperation information accumulation unit 221 (step S403).

[0067] Next, the real-time analysis unit 222 substitutes a value of 1 into the constant i (step S404). The real-time analysis unit 222 determines whether U i i (Step S405). i i The conditions shown are specific examples of the first sleep release condition. When the real-time analysis unit 222 determines that the first sleep release condition (for example, U i i ) (step S405 is "Yes"), the distribution station 14-k that is determined to be in sleep mode is released from sleep mode and the optical path is switched.

[0068] The real-time analysis unit 222 notifies the control unit 23 of the determination result. The sleep control unit 232 sends a sleep-release instruction to the sleep distribution station 14-k based on the determination result (step S406). The optical path switching control unit 231 obtains information about the wireless station 12 connected to the distribution station 14-k before the sleep, from the information obtained in the process of step S402. The optical path switching control unit 231 instructs the wireless station 12 connected to the distribution station 14-k before the sleep to change the connection to the distribution station 14-k.

[0069] In the process of step S405, the real-time analysis unit 222 determines that the first sleep release condition (for example, U i i ) (step S405 is "No"), it is determined whether i is the maximum value (step S408). When the real-time analysis unit 222 determines that i is the maximum value (step S408 is "Yes"), the processing ends.

[0070] On the other hand, when the real-time analysis unit 222 determines that i is not the maximum value (No in step S408), it adds 1 to the value of i (step S409). Then, the real-time analysis unit 222 executes the process of step S405 again.

[0071] Here, in Figure 6 ​​​​In the processing, specific numerical values are used for illustration. As an example, assume that the total number of distribution stations 14 is 2 (I = 2), the maximum number of terminals accommodated by distribution station 14-1 is 1000, the number of terminals accommodated by distribution station 14-1 is 800, the maximum number of terminals accommodated by distribution station 14-2 is 800, and the number of terminals accommodated by distribution station 14-2 is 1000.

[0072] When i = 1, U1 < u1 is 1000 > 800, and the first sleep release condition is not satisfied. The real-time analysis unit 222 determines that the first sleep release condition is not satisfied (for example, U i <u i ) (step S405 is "No"), and determines whether i is the maximum value (step S408). Currently, since i = 1, the real-time analysis unit 222 determines that i is not the maximum value.

[0073] The real-time analysis unit 222 adds 1 to the value of i, and i becomes 2. The real-time analysis unit 222 executes the process of step S405 again. When i = 2, U2 < u2 is 800 < 1000, and the first sleep release condition is satisfied. Then, the processes of steps S406 and S407 are executed.

[0074] Figure 7 It is a sequence diagram showing an example of the detailed process of the sleep release process executed by the mobile NW system 100 of the first embodiment. In addition, in the Figure 7 description, it is assumed that distribution station 14-2 is in a sleep state.

[0075] Distribution station 14-2 is in a sleep state (step S501). The acquisition unit 211 of the management control device 20 acquires cooperation information from distribution station 14-1 at a prescribed cycle (step S502). The acquisition unit 211 accumulates the acquired cooperation information in the cooperation information accumulation unit 221. When the cooperation information is accumulated in the cooperation information accumulation unit 221, the real-time analysis unit 222 performs optical path switching and sleep control judgment (step S503). The optical path switching and sleep control judgment in step S503 is whether the sleep release condition is satisfied. Here, it is assumed that the sleep release condition is satisfied.

[0076] The sleep control unit 232 of the management control device 20 sends a sleep release notice to distribution station 14-2 (step S504). The sleep release notice is a signal including content indicating the release of the sleep state. In response to the reception of the sleep release notice, distribution station 14-2 sends a sleep release response notice to the management control device 20 (step S505). The sleep release response notice is a signal including content indicating the reception of the sleep release notice.

[0077] The optical path switching control unit 231 notifies the switching device 13 and the aggregation station 15 of the optical path switching destination information (step S506). When the switching device 13 receives the optical path switching destination information from the management control device 20, it instructs the wireless station 12, the distribution station 14-1, and the distribution station 14-2 to switch the optical path (step S507).

[0078] The wireless station 12, the distribution station 14-1 and the distribution station 14-2 prepare for the switching of the optical path (steps S508, S509 and S510). When the wireless station 12, the distribution station 14-1 and the distribution station 14-2 have completed the switching preparation of the optical path, an optical path switching response notification showing the completion of the switching preparation is sent to the switching device 13 (steps S511, S512 and S513).

[0079] When receiving the optical path switching response notification from the wireless station 12, the distribution station 14-1 and the distribution station 14-2, the switching device 13 transmits an optical path switching start notification to the wireless station 12, the distribution station 14-1 and the distribution station 14-2 (step S514).

[0080] The wireless station 12, the distribution station 14-1, and the distribution station 14-2 switch the optical path in response to the reception of the optical path switching start notification (steps S515, S516, and S517). The distribution station 14-1 sends a path switching request to the core device 16 (step S518). The core device 16 switches the path in response to the reception of the path switching request (step S519). When the path switching is completed, the core device 16 sends a path switching response notification to the distribution station 14-1 (step S520).

[0081] When the optical path switching is completed, the wireless station 12 sends an optical path switching completion notification to the management control device 20 (step S521). When the optical path switching is completed, the distribution station 14-1 sends an optical path switching completion notification to the management control device 20 (step S522). When the optical path switching is completed, the distribution station 14-2 sends an optical path switching completion notification to the management control device 20 (step S523).

[0082] According to the mobile NW system 100 configured as described above, there are provided one or more wireless stations 12 that wirelessly communicate with one or more terminals 11, a plurality of distribution stations 14 that are connected to the one or more wireless stations 12 via a switching device 13, a coordination information collecting unit 21 that acquires coordination information showing the communication status between the plurality of distribution stations 14 and the one or more terminals 11 at a predetermined period, an optical path switching control unit 231 that controls the switching of the optical paths between the one or more wireless stations 12 and the plurality of distribution stations 14 when it is determined based on the coordination information that the switching of the optical paths between the one or more wireless stations 12 and the plurality of distribution stations 14 is necessary, and a sleep control unit 232 that causes the distribution stations that can sleep to shift to the sleep state after the switching of the optical paths. Thus, the switching of the optical paths and the sleep control are performed while analyzing the load of each distribution station 14. Therefore, the effect of power saving can be increased without deteriorating the communication quality.

[0083] (Variation 1 of the First Embodiment) In the above embodiment, the management control device 20 directly obtains the coordination information from the distribution station 14. The management control device 20 may obtain the coordination information via other devices. Here, the other devices are, for example, wireless controllers. Figure 8 1 is a diagram showing a configuration example of a mobile NW system 100a according to a first modification of the first embodiment. The mobile NW system 100a includes one or more wireless stations 12, a switching device 13, a plurality of distribution stations 14, a collection station 15, a core device 16, a management control device 20, and a wireless controller 30a. Figure 8 As shown, in the mobile NW system 100 a , a wireless controller 30 a is provided between the management control device 20 and the distribution station 14 .

[0084] The wireless controller 30a obtains the coordination information from each distribution station 14 at a predetermined period through wireless communication. The wireless controller 30a transmits the obtained coordination information to the management control device 20 through wireless communication. In addition, the wireless controller 30a may receive a sleep control instruction from the management control device 20 and transmit it to the switching source distribution station. With this configuration, it is possible to collect cooperation information through wireless communication.

[0085] (Variation 2 of the first embodiment) In the above embodiment, the management control device 20 performs the switching control process of the optical path and the sleep control process. On the other hand, the switching device 13 may perform the switching control process of the optical path and the sleep control process. Fig. 9The figure shows a configuration example of a mobile NW system 100b according to Modification 2 of the first embodiment. The mobile NW system 100b includes one or more wireless stations 12, a switching device 13b, a plurality of distribution stations 14, a hub station 15, a core device 16, and a management control device 20b.

[0086] like Fig. 9 As shown, the switching device 13b includes the control unit 23, and the management control device 20b does not include the control unit 23. The real-time analysis unit 222 of the management control device 20b notifies the switching device 13b of the analysis result. In addition, the real-time analysis unit 222 may also notify the switching device 13b of the analysis result only when the optical path switching and sleep control are performed. The control unit 23 of the switching device 13b performs the optical path switching control processing and the sleep control processing based on the analysis result notified from the management control device 20b.

[0087] Fig.10 1 is a sequence diagram showing an example of a detailed flow of the sleep process executed by the mobile NW system 100b according to the second modification of the first embodiment. Fig.10 In Figure 5 Same treatment, annotated with Figure 5 The same symbols are used and the description is omitted. Fig.10 In the description, it is assumed that the distribution station 14-1 is the switching destination distribution station and the distribution station 14-2 is the switching source distribution station. Here, the description is given as the switching destination distribution station 14-1 and the switching source distribution station 14-2.

[0088] After executing the processes from step S301 to step S303, the real-time analysis unit 222 instructs the switching device 13b to switch the optical path and perform sleep control if the first switching condition is satisfied (step S601). The switching device 13b receives the instruction sent from the management control device 20b.

[0089] The optical path switching control unit 231 of the switching device 13b determines the switching destination of the optical path based on the information included in the received instruction (step S602). The optical path switching control unit 231 notifies the aggregation station 15 of the optical path switching destination information (step S603). Thereafter, the optical path switching control unit 231 instructs the wireless station 12 connected to the switching source distribution station 14-2, the switching destination distribution station 14-1, and the switching source distribution station 14-2 to switch the optical path (step S604). Then, the processing of steps S306 to S317 is executed.

[0090] When the optical path switching is completed, the wireless station 12 sends an optical path switching completion notification to the switching device 13b (step S605). In addition, the wireless station 12 may also send an optical path switching completion notification to the management control device 20b. When the optical path switching is completed, the switching destination distribution station 14-1 sends an optical path switching completion notification to the switching device 13b (step S606). In addition, the wireless station 12 may also send an optical path switching completion notification to the management control device 20b.

[0091] When the sleep control unit 232 of the switching device 13b receives the optical path switching completion notification from the destination of the optical path switching start notification, it sends a sleep permission notification to the switching source distribution station 14-2 (step S607). When the switching source distribution station 14-2 receives the sleep permission notification from the switching device 13b, it sends a sleep response notification to the switching device 13b (step S608). After sending the sleep response notification, the switching source distribution station 14-2 transitions to the sleep state (step S322).

[0092] Fig.11 1 is a sequence diagram showing an example of a detailed flow of the sleep release process executed by the mobile NW system 100b according to the second modification of the first embodiment. Fig.11 In Figure 7 Same treatment, annotated with Figure 7 The same symbols are used and the description is omitted. Fig.11 In the description, it is assumed that the distribution station 14-2 is in a sleep state.

[0093] After executing the processes from step S501 to step S503, the real-time analysis unit 222 instructs the switching device 13b to switch the optical path and perform the sleep control if the sleep release condition is satisfied (step S701). The switching device 13b receives the instruction sent from the management control device 20b.

[0094] The sleep control unit 232 of the switching device 13b transmits a sleep release notification to the distribution station 14-2 based on the information included in the received instruction (step S702). In response to receiving the sleep release notification, the distribution station 14-2 transmits a sleep release response notification to the switching device 13b (step S703).

[0095] The optical path switching control unit 231 of the switching device 13b determines the switching destination of the optical path based on the information included in the received instruction (step S704). The optical path switching control unit 231 of the switching device 13b notifies the aggregation station 15 of the optical path switching destination information (step S705). Then, the processing of steps S507 to S520 is executed.

[0096] When the optical path switching is completed, the wireless station 12 sends an optical path switching completion notification to the switching device 13b (step S706). When the optical path switching is completed, the distribution station 14-1 sends an optical path switching completion notification to the switching device 13b (step S707). When the optical path switching is completed, the distribution station 14-2 sends an optical path switching completion notification to the switching device 13b (step S708).

[0097] (Second Embodiment) The second embodiment differs from the first embodiment in that the coordination information further includes processing load information (e.g., information on the usage rate of the memory of each distribution station or information on the usage rate of the CPU). In the second embodiment, the information on the usage rate of the memory of each distribution station is used as an example of the processing load information.

[0098] Fig.12 1 is a diagram showing a configuration example of a mobile NW system 100c according to a second embodiment. The mobile NW system 100c according to the second embodiment includes one or more wireless stations 12, a switching device 13, a plurality of distribution stations 14, a collection station 15, a core device 16, and a management control device 20c. The management control device 20c includes a collaboration information collection unit 21c, an analysis unit 22c, and a control unit 23.

[0099] The coordination information collecting unit 21c includes an acquiring unit 211 and a distributed station monitoring unit 212c. The distributed station monitoring unit 212c monitors each distributed station 14 and measures the memory usage rate for each distributed station 14. The distributed station monitoring unit 212c outputs information on the memory usage rate measured for each distributed station 14 to the analyzing unit 22c as coordination information.

[0100] The analysis unit 22c includes a collaboration information accumulation unit 221 and a real-time analysis unit 222c. The real-time analysis unit 222c analyzes the communication status in the mobile NW system 100c, such as the change in the number of connections of the distribution station 14 per unit time, based on the collaboration information. Specifically, the real-time analysis unit 222c divides the memory usage rate by the current number of accommodated terminals to calculate the memory usage rate of each. In addition, the real-time analysis unit 222c multiplies the number of accommodated terminals of other distribution stations 14 by the memory usage rate of each of the target distribution stations 14. When the memory usage rate does not exceed 100% and the number of accommodated terminals of the distribution station 14 is less than the number of terminals that can be additionally accommodated in the target distribution station 14, the optical path switching and sleep are determined.

[0101] Fig.13 2 is a flowchart showing an example of the process of the sleep process executed by the management control device 20c of the second embodiment. Fig.13 In Figure 3 Same treatment, annotated with Figure 3 The same symbols are used and the description is omitted.

[0102] The collaboration information collecting unit 21c obtains collaboration information from each distribution station 14 (step S801). Specifically, the acquiring unit 211 obtains at least information on the number of accommodated terminals and information on the maximum number of accommodated terminals from each distribution station 14 as collaboration information. Furthermore, the distribution station monitoring unit 212c measures the memory usage rate for each distribution station 14. The collaboration information collecting unit 21c accumulates the acquired collaboration information of each distribution station 14 in the collaboration information accumulating unit 221 (step S802). Specifically, the collaboration information collecting unit 21c accumulates the information on the memory usage rate of each distribution station 14 in the collaboration information accumulating unit 221 as collaboration information in addition to the collaboration information including at least information on the number of accommodated terminals and information on the maximum number of accommodated terminals from each distribution station 14.

[0103] The real-time analysis unit 222c calculates the number of terminals that can be additionally accommodated in each distribution station 14 based on the cooperation information of each distribution station 14 accumulated in the cooperation information accumulation unit 221 (step S803). In addition, the real-time analysis unit 222c roughly estimates the memory usage rate of each distribution station 14 based on the cooperation information of each distribution station 14 accumulated in the cooperation information accumulation unit 221 (step S804).

[0104] The real-time analysis unit 222c determines whether the second switching condition is satisfied (step S805). The second switching condition is a condition indicating that the optical path between the wireless station 12 and the distribution station 14 needs to be switched, for example, the number of additional accommodating terminals of a certain distribution station 14 is greater than the number of accommodating terminals of the distribution station 14 that is the target of the sleep determination and the memory usage rate does not exceed 100%.

[0105] When the real-time analysis unit 222c determines that the second switching condition is satisfied (step S805: Yes), the processing from step S105 onwards is performed. On the other hand, when the real-time analysis unit 222c determines that the second switching condition is not satisfied (step S805: No), the processing from step S107 onwards is performed.

[0106] Fig.14 2 is a flowchart showing an example of the process of the sleep process executed by the management control device 20c of the second embodiment. Fig.14 The processing illustrated in the figure more specifically shows Fig.13 The content of the processing shown. Fig.14 In Figure 4 Same treatment, annotated with Figure 4 The same symbols are used and the description is omitted.

[0107] The acquisition unit 211 acquires the maximum number of accommodated terminals, connected wireless station information, and accommodated terminal number information of each distribution station as coordination information from each distribution station 14. In addition, the distribution station monitoring unit 212c acquires memory usage information of each distribution station 14 (step S901).

[0108] The acquisition unit 211 accumulates the acquired coordination information of each distribution station 14 in the coordination information accumulation unit 221. The distribution station monitoring unit 212c accumulates the acquired information of the memory usage rate of each distribution station 14 as coordination information (step S902). The real-time analysis unit 222c calculates the number of terminals that can be additionally accommodated in each distribution station 14 based on the coordination information of each distribution station 14 accumulated in the coordination information accumulation unit 221 (step S903). Furthermore, the real-time analysis unit 222c roughly calculates the memory usage rate of each distribution station 14 based on the coordination information of each distribution station 14 accumulated in the coordination information accumulation unit 221 (step S904).

[0109] Next, the real-time analysis unit 222c substitutes the value of 1 into the constant i (step S905). Next, the real-time analysis unit 222c substitutes the value of (i+1) into k (step S906). Then, the real-time analysis unit 222c determines whether 100-M is satisfied. i >m i ×u k AndU i -u i >u k (Step S907). i represents the memory usage of the distribution station 14-i, m i Indicates the memory usage rate of each distribution station 14. i Calculated in the process of step S904. 100-M i >m i ×u k AndU i -u i >u k The conditions shown are specific examples of the second switching conditions.

[0110] When the real-time analysis unit 222c determines that the second switching condition is satisfied (step S907: Yes), the real-time analysis unit 222c performs the processing from step S207 onwards. On the other hand, when the real-time analysis unit 222c determines that the second switching condition is not satisfied (step S907: No), the real-time analysis unit 222c performs the processing from step S209 onwards.

[0111] Here, in Fig.14In the processing of , specific numerical values ​​are used for explanation. As an example, it is assumed that the maximum number of terminals accommodated in the distribution station 14-1 is 1000, the number of terminals accommodated in the distribution station 14-1 is 100, and the memory usage rate M1 of the distribution station 14-1 is 20%, the maximum number of terminals accommodated in the distribution station 14-2 is 800, the number of terminals accommodated in the distribution station 14-2 is 200, and the memory usage rate M2 of the distribution station 14-2 is 30%. In this case, in the processing of step S904, the real-time analysis unit 222c calculates m1=20 / 100=0.2 and m2=30 / 200=0.15 as the estimated values ​​of the memory usage rate of each distribution station 14. m1 represents the estimated value of the memory usage rate of each distribution station 14-1, and m2 represents the estimated value of the memory usage rate of each distribution station 14-2.

[0112] In the process of step S907, the real-time analysis unit 222c determines whether the 100-M i >m i ×u k AndU i -u i >u k When i=1 and k=2, it is expressed as follows: · · ·

[0113] According to the above results, 100-M i >m i ×u k AndU i -u i >u k 180>40 and 900>200. In this case, the real-time analysis unit 222c determines that the second switching condition is satisfied. Therefore, the real-time analysis unit 222c switches the judgment so that the wireless station 12 connected to the distribution station 14-2 is connected to the distribution station 14-1, and judges the sleep state so that the distribution station 14-2 is transferred to the sleep state. The real-time analysis unit 222c notifies the optical path switching control unit 231 of the result of switching the judgment so that the wireless station 12 connected to the distribution station 14-2 is connected to the distribution station 14-1, and notifies the sleep control unit 232 of the judgment result that the sleep state causes the distribution station 14-2 to transfer to the sleep state.

[0114] Thus, the optical path switching control unit 231 controls the switching of the optical path based on the notification from the real-time analysis unit 222c so that the wireless station 12 connected to the distribution station 14-2 is connected to the distribution station 14-1. The sleep control unit 232 controls the sleep mode based on the notification from the real-time analysis unit 222c so that the distribution station 14-2 shifts to the sleep mode.

[0115] Fig.15 1 is a sequence diagram showing an example of a detailed flow of the sleep process executed by the mobile NW system 100c according to the second embodiment. Fig.15 In Figure 5 Same treatment, annotated with Figure 5 The same symbols are used and the description is omitted. Fig.15 In the description, it is assumed that the distribution station 14-1 is the switching destination distribution station and the distribution station 14-2 is the switching source distribution station. Here, the description is given as the switching destination distribution station 14-1 and the switching source distribution station 14-2.

[0116] The coordination information collecting unit 21c of the management control device 20c obtains coordination information from the switching destination distribution station 14-1 and the switching source distribution station 14-2 at a predetermined period (step S1001, step S1002). In addition, the coordination information obtained in step S1001 and step S1002 includes information on the number of accommodated terminals and the maximum number of accommodated terminals, as well as information on the usage rate of the memory of each distribution station 14. The coordination information collecting unit 21c accumulates the obtained coordination information in the coordination information accumulating unit 221.

[0117] When the cooperation information is accumulated in the cooperation information accumulation unit 221, the real-time analysis unit 222c performs the switching of the optical path and the sleep control judgment (step S1003). The switching of the optical path and the sleep control judgment in step S1003 are the judgments of whether the second switching condition in step S805 is satisfied. Here, it is assumed that the second switching condition in step S805 is satisfied. When the second switching condition is satisfied, the real-time analysis unit 222c performs the processing after step S304.

[0118] Fig.16 2 is a flowchart showing an example of the process of the sleep release process executed by the management control device 20c of the second embodiment. Fig.16 In Figure 6 Same treatment, annotated with Figure 6 The same symbols are used and the description is omitted.

[0119] The acquisition unit 211 acquires the number of accommodated terminals and the information of the dormant distribution station 14-k from each distribution station 14 as the coordination information. In addition, the distribution station monitoring unit 212c acquires the information of the memory usage rate of each distribution station 14 as the coordination information (step S1101). The acquisition unit 211 notifies the acquired information of the number of accommodated terminals, the dormant distribution station 14-k, and the information of the memory usage rate to the analysis unit 22c.

[0120] The real-time analysis unit 222c of the analysis unit 22c reads the information of the maximum number of accommodated terminals of each distribution station 14 and the information of the wireless station 12 connected to the dormant distribution station 14-k from the cooperation information accumulation unit 221 (step S1102). The real-time analysis unit 222c calculates the number of additionally accommodable terminals of each distribution station 14 based on the obtained cooperation information of each distribution station 14 (step S1103).

[0121] Next, the real-time analysis unit 222c substitutes a value of 1 into the constant i (step S1104). The real-time analysis unit 222c determines whether U i i or T1 <M i Any one of (step S1105). i i or T1 <M i The conditions shown are specific examples of the second sleep release condition. Under the second sleep release condition, T1 < M i This means that the memory utilization M of the distribution station 14-i i Exceeds a threshold value T1 (for example, a predetermined value such as 80, 90, 100%).

[0122] The real-time analysis unit 222c determines that the second sleep release condition (for example, U i i or T1 <M i ) (step S1105: YES), it is determined that the optical path needs to be switched and the dormant distribution station 14-k needs to be de-hibernated.

[0123] The real-time analysis unit 222c notifies the control unit 23 of the determination result. Then, the processing after step S406 is executed. On the other hand, if the real-time analysis unit 222c determines that the second sleep release condition (for example, U i i or T1 <M i ) (step S1105 is "No"), execute the processing of step S408.

[0124] Fig.17 1 is a sequence diagram showing an example of a detailed flow of the sleep release process executed by the mobile NW system 100c according to the second embodiment. Fig.17 In Figure 7 Same treatment, annotated with Figure 7 The same symbols are used and the description is omitted. Fig.17 In the description, it is assumed that the distribution station 14-2 is in a sleep state.

[0125] ​​​​The distribution station 14-2 is in a dormant state (step S501). The coordination information collecting unit 21c of the management control device 20c obtains coordination information from the distribution station 14-1 at a predetermined period (step S1201). In addition, the coordination information obtained in step S1201 includes information on at least the number of accommodated terminals and the maximum number of accommodated terminals, as well as information on the usage rate of the memory of each distribution station 14. The coordination information collecting unit 21c accumulates the obtained coordination information in the coordination information accumulating unit 221.

[0126] When the cooperation information is accumulated in the cooperation information accumulation unit 221, the real-time analysis unit 222c performs the switching of the optical path and the sleep control judgment (step S1202). The switching of the optical path and the sleep control judgment in step S1202 are to determine whether the sleep release condition is satisfied. Here, it is assumed that the sleep release condition is satisfied. When the sleep release condition is satisfied, the real-time analysis unit 222c performs the processing after step S504.

[0127] According to the mobile NW system 100c of the second embodiment constructed as described above, the same effect as that of the first embodiment can be obtained. Specifically, in the mobile NW system 100c, the management control device 20c further obtains information on the usage rate of the memory of each distribution station 14 as cooperation information, and determines whether the switching of the optical path is required based on the cooperation information. When the management control device 20c determines that the switching of the optical path is required, it controls the switching of the optical path between one or more wireless stations 12 and multiple distribution stations 14. In addition, after switching the optical path, the management control device 20c causes the distribution station that can sleep to transfer to the sleep state. Thus, while analyzing the load of each distribution station 14, the switching of the optical path and the control of sleep are performed. Therefore, the effect of power saving can be increased without deteriorating the communication quality.

[0128] (Variation 1 of the Second Embodiment) In the above embodiment, the management control device 20c directly obtains the cooperation information from the distribution station 14. The management control device 20c may also obtain the cooperation information via other devices. Here, the other device is, for example, a wireless controller. In such a configuration, the mobile NW system 100c is newly equipped with a wireless controller 30a, and the wireless controller 30a is provided between the management control device 20c and the distribution station 14.

[0129] The wireless controller 30a obtains the cooperation information from each distribution station 14 at a predetermined period through wireless communication. The wireless controller 30a transmits the obtained cooperation information to the management control device 20c through wireless communication. In addition, the wireless controller 30a may receive a sleep control instruction from the management control device 20c and transmit it to the switching source distribution station. With this configuration, it is possible to collect cooperation information through wireless communication.

[0130] (Variation 2 of the Second Embodiment) In the above-mentioned embodiment, a structure is shown in which the management control device 20c performs switching control processing and sleep control processing of the optical path. In contrast, it is also possible to configure the switching device 13 to perform switching control processing and sleep control processing of the optical path. In the case of such a structure, the switching device 13 includes a control unit 23, and the management control device 20c does not include the control unit 23. The real-time analysis unit 222c of the management control device 20c notifies the switching device 13 of the analysis result. In addition, the real-time analysis unit 222c may also notify the switching device 13 of the analysis result only when switching and sleep control of the optical path are performed. The control unit 23 of the switching device 13 performs switching control processing and sleep control processing of the optical path based on the analysis result notified from the management control device 20c.

[0131] Fig.18 1 is a sequence diagram showing an example of a detailed flow of the sleep process executed by the mobile NW system 100c according to the second modification of the second embodiment. Fig.18 In Fig.15 Same treatment, annotated with Fig.15 The same symbols are used and the description is omitted.

[0132] After executing the processes from step S1001 to step S1003, the real-time analysis unit 222c instructs the switching device 13b to switch the optical path and perform sleep control if the second switching condition is satisfied (step S1301). The switching device 13b receives the instruction sent from the management control device 20c.

[0133] The optical path switching control unit 231 of the switching device 13b determines the switching destination of the optical path based on the information included in the received instruction (step S1302). The optical path switching control unit 231 notifies the aggregation station 15 of the optical path switching destination information (step S1303). Thereafter, the optical path switching control unit 231 instructs the wireless station 12 connected to the switching source distribution station 14-2, the switching destination distribution station 14-1, and the switching source distribution station 14-2 to switch the optical path (step S1304). Then, the processing of steps S306 to S317 is performed.

[0134] When the optical path switching is completed, the wireless station 12 sends an optical path switching completion notification to the switching device 13b (step S1305). In addition, the wireless station 12 may also send an optical path switching completion notification to the management control device 20c. When the optical path switching is completed, the switching destination distribution station 14-1 sends an optical path switching completion notification to the switching device 13 (step S1306). In addition, the wireless station 12 may also send an optical path switching completion notification to the management control device 20c.

[0135] When the sleep control unit 232 of the switching device 13b receives the optical path switching completion notification from the destination of the optical path switching start notification, it sends a sleep permission notification to the switching source distribution station 14-2 (step S1307). When the switching source distribution station 14-2 receives the sleep permission notification from the switching device 13, it sends a sleep response notification to the switching device 13b (step S1308). After sending the sleep response notification, the switching source distribution station 14-2 transitions to the sleep state (step S322).

[0136] Fig.19 1 is a sequence diagram showing an example of a detailed flow of the sleep release process executed by the mobile NW system 100c according to the second modification of the second embodiment. Fig.19 In Fig.17 Same treatment, annotated with Fig.17 The same symbols are used and the description is omitted. Fig.17 In the description, it is assumed that the distribution station 14-2 is in a sleep state.

[0137] After executing the processes of step S501, step S1201, and step S1202, the real-time analyzer 222c instructs the switching device 13b to switch the optical path and perform the sleep control if the sleep release condition is satisfied (step S1401). The switching device 13b receives the instruction sent from the management control device 20c.

[0138] The sleep control unit 232 of the switching device 13b transmits a sleep release notification to the distribution station 14-2 based on the information included in the received instruction (step S1402). In response to receiving the sleep release notification, the distribution station 14-2 transmits a sleep release response notification to the switching device 13b (step S1403).

[0139] The optical path switching control unit 231 of the switching device 13b determines the switching destination of the optical path based on the information included in the received instruction (step S1404). The optical path switching control unit 231 of the switching device 13b notifies the aggregation station 15 of the optical path switching destination information (step S1405). Then, the processing of steps S507 to S520 is executed.

[0140] When the optical path switching is completed, the wireless station 12 sends an optical path switching completion notification to the switching device 13b (step S1406). When the optical path switching is completed, the distribution station 14-1 sends an optical path switching completion notification to the switching device 13b (step S1407). When the optical path switching is completed, the distribution station 14-2 sends an optical path switching completion notification to the switching device 13b (step S1408).

[0141] (Third Embodiment) The third embodiment differs from the second embodiment in that the coordination information further includes processing load information (e.g., information on the memory usage rate or CPU usage rate of each distribution station) and processing delay information of each distribution station. The system configuration is the same as that of the second embodiment. The third embodiment is described by taking the information on the memory usage rate of each distribution station as an example of the processing load information.

[0142] The management control device 20c determines the optical path switching and the sleep based on the information of the number of terminals of each distribution station 14, the information of the memory usage rate of each distribution station 14, and the processing delay information of each distribution station 14. For example, the distribution station monitoring unit 212c monitors each distribution station 14 and measures the memory usage rate of each distribution station 14. In addition, the distribution station monitoring unit 212c monitors each distribution station 14 and collects the processing delay information of each distribution station 14. The distribution station monitoring unit 212c outputs the information of the memory usage rate measured for each distribution station 14 and the processing delay information of each distribution station 14 to the analysis unit 22c as the coordination information.

[0143] Fig. 20 2 is a flowchart showing an example of the process of the sleep process executed by the management control device 20c of the third embodiment. Fig. 20 In Fig.13 Same treatment, annotated with Fig.13 The same symbols are used and the description is omitted.

[0144] The collaboration information collecting unit 21c obtains collaboration information from each distribution station 14 (step S1501). Specifically, the acquisition unit 211 obtains at least information on the number of accommodated terminals and information on the maximum number of accommodated terminals from each distribution station 14 as collaboration information. In addition, the distribution station monitoring unit 212c measures the memory usage rate for each distribution station 14 and obtains processing delay information for each distribution station 14. The collaboration information collecting unit 21c accumulates the acquired collaboration information for each distribution station 14 in the collaboration information accumulation unit 221 (step S1502). Specifically, the collaboration information collecting unit 21c accumulates the memory usage rate information for each distribution station 14 and the processing delay information for each distribution station 14 in the collaboration information accumulation unit 221 as collaboration information, in addition to the collaboration information including at least information on the number of accommodated terminals and information on the maximum number of accommodated terminals from each distribution station 14.

[0145] The real-time analysis unit 222c calculates the number of terminals that can be additionally accommodated in each distribution station 14 based on the cooperation information of each distribution station 14 accumulated in the cooperation information accumulation unit 221 (step S1503). In addition, the real-time analysis unit 222c roughly estimates the memory usage rate of each distribution station 14 based on the cooperation information of each distribution station 14 accumulated in the cooperation information accumulation unit 221 (step S1504).

[0146] The real-time analysis unit 222c determines whether the third switching condition is satisfied (step S1505). The third switching condition is a condition indicating that the optical path between the wireless station 12 and the distribution station 14 needs to be switched, for example, the number of additional accommodating terminals of a certain distribution station 14 is greater than the number of accommodating terminals of the distribution station 14 that is the subject of the sleep judgment, the memory usage rate does not exceed 100%, and the processing delay of the distribution station 14 that is the subject of the sleep judgment does not exceed a threshold.

[0147] When the real-time analysis unit 222c determines that the third switching condition is satisfied (step S1505: Yes), the processing from step S105 onwards is performed. On the other hand, when the real-time analysis unit 222c determines that the third switching condition is not satisfied (step S1505: No), the processing from step S107 onwards is performed.

[0148] Fig.21 : is a flowchart showing an example of the process of the sleep process executed by the management control device 20c of the third embodiment. Fig.21 The processing illustrated in the figure more specifically shows Fig. 20 The content of the processing shown. Fig.21 In Fig.14 Same treatment, annotated with Fig.14 The same symbols are used and the description is omitted.

[0149] The acquisition unit 211 acquires the maximum number of accommodated terminals, connected wireless station information, and accommodated terminal number information of each distribution station as cooperation information from each distribution station 14. In addition, the distribution station monitoring unit 212c acquires memory usage information and processing delay information of each distribution station 14 (step S1601).

[0150] The acquisition unit 211 accumulates the acquired coordination information of each distribution station 14 in the coordination information accumulation unit 221. Furthermore, the distribution station monitoring unit 212c accumulates the acquired information of the memory usage rate and the processing delay information of each distribution station 14 as coordination information (step S1602). The real-time analysis unit 222c calculates the number of terminals that can be additionally accommodated in each distribution station 14 based on the coordination information of each distribution station 14 accumulated in the coordination information accumulation unit 221 (step S1603). Furthermore, the real-time analysis unit 222c roughly calculates the memory usage rate of each distribution station 14 based on the coordination information of each distribution station 14 accumulated in the coordination information accumulation unit 221 (step S1604).

[0151] Next, the real-time analysis unit 222c substitutes the value of 1 into the constant i (step S1605). Next, the real-time analysis unit 222c substitutes the value of (i+1) into k (step S1606). Then, the real-time analysis unit 222c determines whether 100-M is satisfied. i >m i ×u k AndU i -u i >u k And T>t i (Step S1607). T represents a threshold value. In the third embodiment, t i Indicates the processing delay of the distribution station 14-i. 100-M i >m i ×u k AndU i -u i >u k And T>t i The conditions shown are specific examples of the third switching conditions.

[0152] When the real-time analysis unit 222c determines that the third switching condition is satisfied (step S1607: Yes), the processing from step S207 onwards is performed. On the other hand, when the real-time analysis unit 222c determines that the third switching condition is not satisfied (step S1607: No), the processing from step S209 onwards is performed.

[0153] Fig. 22 1 is a sequence diagram showing an example of a detailed flow of the sleep process executed by the mobile NW system 100c according to the third embodiment. Fig. 22In Fig.15 Same treatment, annotated with Fig.15 The same symbols are used and the description is omitted. Fig. 22 In the description, it is assumed that the distribution station 14-1 is the switching destination distribution station and the distribution station 14-2 is the switching source distribution station. Here, the description is given as the switching destination distribution station 14-1 and the switching source distribution station 14-2.

[0154] The coordination information collecting unit 21c of the management control device 20c obtains coordination information from the switching destination distribution station 14-1 and the switching source distribution station 14-2 at a predetermined period (step S1701, step S1702). In addition, the coordination information obtained in step S1701 and step S1702 includes information on the usage rate of the memory of each distribution station 14 and processing delay information of each distribution station 14 in addition to at least information on the number of accommodated terminals and information on the maximum number of accommodated terminals. The coordination information collecting unit 21c accumulates the obtained coordination information in the coordination information accumulating unit 221.

[0155] When the cooperation information is accumulated in the cooperation information accumulation unit 221, the real-time analysis unit 222c performs the switching of the optical path and the sleep control judgment (step S1703). The switching of the optical path and the sleep control judgment in step S1703 are the judgments of whether the third switching condition in step S1505 is satisfied. Here, it is assumed that the third switching condition in step S1505 is satisfied. When the fifth switching condition is satisfied, the real-time analysis unit 222c performs the processing after step S304.

[0156] Fig.23 2 is a flowchart showing an example of the process of the sleep release process executed by the management control device 20c of the third embodiment. Fig.23 In Fig.16 Same treatment, annotated with Fig.16 The same symbols are used and the description is omitted.

[0157] The acquisition unit 211 acquires the number of accommodated terminals and the information of the dormant distribution station 14-k from each distribution station 14 as the coordination information. In addition, the distribution station monitoring unit 212c acquires the information of the memory usage rate of each distribution station 14 and the processing delay information of each distribution station 14 as the coordination information (step S1751). The acquisition unit 211 notifies the acquired information of the number of accommodated terminals, the dormant distribution station 14-k, the information of the memory usage rate, and the processing delay information of each distribution station 14 to the analysis unit 22c.

[0158] The real-time analysis unit 222c of the analysis unit 22c reads the information of the maximum number of accommodated terminals of each distribution station 14 and the information of the wireless station 12 connected to the dormant distribution station 14-k from the cooperation information accumulation unit 221 (step S1752). The real-time analysis unit 222c calculates the number of additionally accommodable terminals of each distribution station 14 based on the obtained cooperation information of each distribution station 14 (step S1753).

[0159] Next, the real-time analysis unit 222c substitutes a value of 1 into the constant i (step S1754). The real-time analysis unit 222c determines whether U i i or T1 <M i or T <t i Any one of (step S1755). i i or T1 <M i or T <t i The conditions shown are specific examples of the third sleep release condition. Under the third sleep release condition, T<t i This means that the processing delay of the distribution station 14-i exceeds the threshold.

[0160] The real-time analysis unit 222c determines that the third sleep release condition (for example, U i i , or T1 <M i , or T <t i ) (step S1755 is "Yes"), it is determined that the optical path needs to be switched and the dormant distribution station 14-k needs to be de-hibernated.

[0161] The real-time analysis unit 222c notifies the control unit 23 of the determination result. Then, the processing after step S406 is executed. On the other hand, if the real-time analysis unit 222c determines that the third sleep release condition (for example, U i i , or T1 <M i , or T <t i ) (step S1755 is "No"), execute the processing of step S408.

[0162] Fig.24 1 is a sequence diagram showing an example of a detailed flow of the sleep release process executed by the mobile NW system 100c according to the third embodiment. Fig.24 In Fig.17 Same treatment, annotated with Fig.17 The same symbols are used and the description is omitted. Fig.17 In the description, it is assumed that the distribution station 14-2 is in a sleep state.

[0163] ​​​​The distribution station 14-2 is in a dormant state (step S501). The coordination information collecting unit 21c of the management control device 20c obtains coordination information from the distribution station 14-1 at a predetermined period (step S1801). In addition, the coordination information obtained in step S1801 includes information on the usage rate of the memory of each distribution station 14 and processing delay information. The coordination information collecting unit 21c accumulates the obtained coordination information in the coordination information accumulating unit 221.

[0164] When the cooperation information is accumulated in the cooperation information accumulation unit 221, the real-time analysis unit 222c performs the switching of the optical path and the sleep control judgment (step S1802). The switching of the optical path and the sleep control judgment in step S1802 are to determine whether the sleep release condition is satisfied. Here, it is assumed that the sleep release condition is satisfied. When the sleep release condition is satisfied, the real-time analysis unit 222c performs the processing after step S504.

[0165] According to the mobile NW system 100c of the third embodiment constructed as described above, the same effect as that of the first embodiment can be obtained. Specifically, in the mobile NW system 100c of the third embodiment, the management control device 20c further obtains information on the usage rate of the memory of each distribution station 14 and the processing delay information of each distribution station 14 as cooperation information, and determines whether the switching of the optical path is required based on the cooperation information. When it is determined that the switching of the optical path is required, the management control device 20c controls the switching of the optical paths between one or more wireless stations 12 and multiple distribution stations 14. In addition, after switching the optical path, the management control device 20c causes the distribution station that can sleep to transfer to the sleep state. Thus, while analyzing the load of each distribution station 14, the switching of the optical path and the control of sleep are performed. Therefore, the effect of power saving can be increased without deteriorating the communication quality.

[0166] (Variation 1 of the Third Embodiment) In the above embodiment, the management control device 20c directly obtains the cooperation information from the distribution station 14. The management control device 20c may also obtain the cooperation information via other devices. Here, the other device is, for example, a wireless controller. In such a configuration, the mobile NW system 100c is newly equipped with a wireless controller 30a, and the wireless controller 30a is provided between the management control device 20c and the distribution station 14.

[0167] The wireless controller 30a obtains the cooperation information from each distribution station 14 at a predetermined period through wireless communication. The wireless controller 30a transmits the obtained cooperation information to the management control device 20c through wireless communication. In addition, the wireless controller 30a may receive a sleep control instruction from the management control device 20c and transmit it to the switching source distribution station. With this configuration, it is possible to collect cooperation information through wireless communication.

[0168] (Variation 2 of the Third Embodiment) In the above-mentioned embodiment, a structure is shown in which the management control device 20c performs switching control processing and sleep control processing of the optical path. In contrast, it is also possible to configure the switching device 13 to perform switching control processing and sleep control processing of the optical path. In the case of such a structure, the switching device 13 includes a control unit 23, and the management control device 20c does not include the control unit 23. The real-time analysis unit 222c of the management control device 20c notifies the switching device 13 of the analysis result. In addition, the real-time analysis unit 222c may also notify the switching device 13 of the analysis result only when switching and sleep control of the optical path are performed. The control unit 23 of the switching device 13 performs switching control processing and sleep control processing of the optical path based on the analysis result notified from the management control device 20c.

[0169] Fig.25 : is a sequence diagram showing an example of a detailed flow of the sleep process executed by the mobile NW system 100c according to the second modification of the third embodiment. Fig.25 In Fig. 22 Same treatment, annotated with Fig. 22 The same symbols are used and the description is omitted.

[0170] After executing the processes from step S1701 to step S1703, the real-time analysis unit 222c instructs the switching device 13b to switch the optical path and perform sleep control if the third switching condition is satisfied (step S1901). The switching device 13b receives the instruction sent from the management control device 20c.

[0171] The optical path switching control unit 231 of the switching device 13b determines the switching destination of the optical path based on the information included in the received instruction (step S1902). The optical path switching control unit 231 notifies the aggregation station 15 of the optical path switching destination information (step S1903). Thereafter, the optical path switching control unit 231 instructs the wireless station 12 connected to the switching source distribution station 14-2, the switching destination distribution station 14-1, and the switching source distribution station 14-2 to switch the optical path (step S1904). Then, the processing of steps S306 to S317 is performed.

[0172] When the optical path switching is completed, the wireless station 12 sends an optical path switching completion notification to the switching device 13b (step S1905). In addition, the wireless station 12 may also send an optical path switching completion notification to the management control device 20c. When the optical path switching is completed, the switching destination distribution station 14-1 sends an optical path switching completion notification to the switching device 13 (step S1906). In addition, the wireless station 12 may also send an optical path switching completion notification to the management control device 20c.

[0173] When the sleep control unit 232 of the switching device 13b receives the optical path switching completion notification from the destination of the optical path switching start notification, it sends a sleep permission notification to the switching source distribution station 14-2 (step S1907). When the switching source distribution station 14-2 receives the sleep permission notification from the switching device 13, it sends a sleep response notification to the switching device 13b (step S1908). After sending the sleep response notification, the switching source distribution station 14-2 transitions to the sleep state (step S322).

[0174] Fig.26 1 is a sequence diagram showing an example of a detailed flow of the sleep release process executed by the mobile NW system 100c according to the second modification of the third embodiment. Fig.26 In Fig.23 Same treatment, annotated with Fig.23 The same symbols are used and the description is omitted.

[0175] After executing the processes of step S501, step S1801 and step S1802, the real-time analyzer 222c instructs the switching device 13b to switch the optical path and perform the sleep control if the sleep release condition is satisfied (step S2001). The switching device 13b receives the instruction sent from the management control device 20c.

[0176] The sleep control unit 232 of the switching device 13b sends a sleep release notification to the distribution station 14-2 based on the information included in the received instruction (step S2002). In response to receiving the sleep release notification, the distribution station 14-2 sends a sleep release response notification to the switching device 13b (step S2003).

[0177] The optical path switching control unit 231 of the switching device 13b determines the switching destination of the optical path based on the information included in the received instruction (step S2004). The optical path switching control unit 231 of the switching device 13b notifies the aggregation station 15 of the optical path switching destination information (step S2005). Then, the processing of steps S507 to S520 is executed.

[0178] When the optical path switching is completed, the wireless station 12 sends an optical path switching completion notification to the switching device 13b (step S2006). When the optical path switching is completed, the distribution station 14-1 sends an optical path switching completion notification to the switching device 13b (step S2007). When the optical path switching is completed, the distribution station 14-2 sends an optical path switching completion notification to the switching device 13b (step S2008).

[0179] (Fourth Embodiment) The fourth embodiment is different from the first embodiment in that the coordination information also includes information on the transmission delay between the terminal 11 and each distribution station 14 .

[0180] Fig. 27 1 is a diagram showing a configuration example of a mobile NW system 100d according to a fourth embodiment. The mobile NW system 100d according to the fourth embodiment includes one or more wireless stations 12, a switching device 13, a plurality of distribution stations 14, a collection station 15, a core device 16, and a management control device 20d. The management control device 20d includes a coordination information collection unit 21d, an analysis unit 22d, and a control unit 23.

[0181] The coordination information collecting unit 21d includes an acquiring unit 211 and a delay measuring unit 213d. The delay measuring unit 213d measures the transmission delay between the terminal 11 and each distribution station 14. For example, the delay measuring unit 213d measures the transmission delay between the terminal 11 and each distribution station 14 based on the RTT (Round-Trip Time) obtained as a result of sending Ping. The delay measuring unit 213d outputs the information of the propagation delay measured for each distribution station 14 to the analyzing unit 22d as coordination information.

[0182] The analysis unit 22d includes a collaboration information accumulation unit 221 and a real-time analysis unit 222d. The real-time analysis unit 222d analyzes the communication status in the mobile NW system 100d, such as the change in the number of connections of the distribution station 14 per unit time, based on the collaboration information. Specifically, the real-time analysis unit 222d divides the delay time by the current number of accommodated terminals to calculate the delay time of each one. In addition, the real-time analysis unit 222d multiplies the number of accommodated terminals of other distribution stations 14 by the delay time of each of the target distribution stations 14. When the delay time does not exceed the threshold and the number of accommodated terminals of the distribution station 14 is less than the number of terminals that can be additionally accommodated in the target distribution station 14, the optical path switching and sleep are determined.

[0183] Fig.28 2 is a flowchart showing an example of the process of the sleep process executed by the management control device 20d according to the fourth embodiment. Fig.28 In Figure 3 Same treatment, annotated with Figure 3 The same symbols are used and the description is omitted.

[0184] The delay measuring unit 213d measures the transmission delay between the terminal 11 and each distribution station 14 (step S2101). The cooperation information collecting unit 21d obtains cooperation information from each distribution station 14 (step S2102). Specifically, the obtaining unit 211 obtains at least information on the number of accommodated terminals and information on the maximum number of accommodated terminals from each distribution station 14 as cooperation information. The cooperation information collecting unit 21d accumulates the obtained cooperation information of each distribution station 14 in the cooperation information accumulation unit 221 (step S2103). Specifically, the cooperation information collecting unit 21d accumulates information on the transmission delay between the terminal 11 and each distribution station 14 in the cooperation information accumulation unit 221 as cooperation information in addition to cooperation information including at least information on the number of accommodated terminals and information on the maximum number of accommodated terminals from each distribution station 14.

[0185] The real-time analysis unit 222d calculates the number of terminals that can be additionally accommodated in each distribution station 14 based on the cooperation information of each distribution station 14 accumulated in the cooperation information accumulation unit 221 (step S2104). In addition, the real-time analysis unit 222d estimates the delay time of each distribution station 14 based on the information on the transmission delay between the terminal 11 and each distribution station 14 accumulated in the cooperation information accumulation unit 221 (step S2105).

[0186] The real-time analysis unit 222d determines whether the fourth switching condition is satisfied (step S2106). The fourth switching condition is a condition indicating that the optical path between the wireless station 12 and the distribution station 14 needs to be switched, for example, the number of additional accommodating terminals of a certain distribution station 14 is greater than the number of accommodating terminals of the distribution station 14 that is the target of the sleep determination and the transmission delay does not exceed the threshold.

[0187] When the real-time analysis unit 222d determines that the fourth switching condition is satisfied (step S2106: Yes), it executes the processing from step S105 onwards. On the other hand, when the real-time analysis unit 222d determines that the second switching condition is not satisfied (step S2106: No), it executes the processing from step S107 onwards.

[0188] Fig.29 This is a flowchart showing an example of the process of the sleep process executed by the management control device 20d of the fourth embodiment. Fig.29 The processing illustrated in the figure more specifically shows Fig.28 The content of the processing shown. Fig.29 In Figure 4 Same treatment, annotated with Figure 4 The same symbols are used and the description is omitted.

[0189] The delay measuring unit 213d measures the transmission delay between the terminal 11 and each distribution station 14 (step S2201). The acquiring unit 211 acquires the maximum number of accommodated terminals, connected wireless station information, and accommodated terminal number information of each distribution station as coordination information from each distribution station 14 (step S2202).

[0190] The acquisition unit 211 accumulates the acquired coordination information of each distribution station 14 in the coordination information accumulation unit 221 (step S2203). The real-time analysis unit 222d calculates the number of terminals that can be additionally accommodated in each distribution station 14 based on the coordination information of each distribution station 14 accumulated in the coordination information accumulation unit 221 (step S2204). Furthermore, the real-time analysis unit 222d roughly estimates the transmission delay of each distribution station 14 based on the information of the measured transmission delay between the terminal 11 and each distribution station 14 (step S2205).

[0191] Specifically, the real-time analysis unit 222d calculates the transmission delay value T of the distribution station 14-i obtained in the process of step S2201. i Divided by the number of terminals u accommodated by the distribution station 14-i i After (T i / u i ), to estimate the transmission delay t of each distribution station 14-i i Next, the real-time analysis unit 222d substitutes the value of 1 into the constant i (step S2206). Next, the real-time analysis unit 222d substitutes the value of (i+1) into k (step S2207).

[0192] Then, the real-time analysis unit 222d determines whether i -u i >u k And T>t i ×(u i +u k )(Step S2208). t in the fourth embodiment i represents the transmission delay t of each of the distribution stations 14-i i .U i -u i >u k And T>t i ×(u i +u k ) is a specific example of the fourth switching condition. When the real-time analysis unit 222d determines that the fourth switching condition is satisfied (step S2208 is "Yes"), it executes the processing after step S207. On the other hand, when the real-time analysis unit 222d determines that the second switching condition is not satisfied (step S2208 is "No"), it executes the processing after step S209.

[0193] Fig.30 1 is a sequence diagram showing an example of a detailed flow of the sleep process executed by the mobile NW system 100d according to the fourth embodiment. Fig.30 In Figure 5 Same treatment, annotated with Figure 5 The same symbols are used and the description is omitted. Fig.30 In the description, it is assumed that the distribution station 14-1 is the switching destination distribution station and the distribution station 14-2 is the switching source distribution station. Here, the description is given as the switching destination distribution station 14-1 and the switching source distribution station 14-2.

[0194] The coordination information collecting unit 21d of the management control device 20d obtains coordination information from the switching destination distribution station 14-1 and the switching source distribution station 14-2 at a predetermined period (step S2301, step S2302). In addition, the coordination information obtained in step S2301 and step S2302 includes information on the number of accommodated terminals and the maximum number of accommodated terminals, as well as information on the transmission delay between the terminal 11 and each distribution station 14. The coordination information collecting unit 21d accumulates the obtained coordination information in the coordination information accumulating unit 221.

[0195] When the cooperation information is accumulated in the cooperation information accumulation unit 221, the real-time analysis unit 222d performs the switching of the optical path and the sleep control judgment (step S2303). The switching of the optical path and the sleep control judgment in step S2303 are the judgments of whether the fourth switching condition in step S2106 is satisfied. Here, it is assumed that the fourth switching condition in step S2106 is satisfied. When the fourth switching condition is satisfied, the real-time analysis unit 222d performs the processing after step S304.

[0196] Fig.31 2 is a flowchart showing an example of the process of the sleep release process executed by the management control device 20d according to the fourth embodiment. Fig.31 In Figure 6 Same treatment, annotated with Figure 6 The same symbols are used and the description is omitted.

[0197] The delay measuring unit 213d measures the transmission delay between the terminal 11 and each distribution station 14 (step S2401). The acquisition unit 211 acquires the number of accommodated terminals and the information of the dormant distribution station 14-k from each distribution station 14 as the cooperation information (step S2402). The acquisition unit 211 notifies the acquired number of accommodated terminals, the information of the dormant distribution station 14-k, and the transmission delay information to the analysis unit 22d.

[0198] The real-time analysis unit 222d of the analysis unit 22d reads the information of the maximum number of accommodated terminals of each distribution station 14 and the information of the wireless station 12 connected to the dormant distribution station 14-k from the cooperation information accumulation unit 221 (step S2403). The real-time analysis unit 222d calculates the number of additionally accommodable terminals of each distribution station 14 based on the obtained cooperation information of each distribution station 14 (step S2404).

[0199] Next, the real-time analysis unit 222d substitutes a value of 1 into the constant i (step S2405). The real-time analysis unit 222d determines whether U i i or T <t i (Step S2406). i i or T <t i The condition shown is a specific example of the fourth sleep release condition. Under the fourth sleep release condition, T <t i This means that the transmission delay between the terminal 11 and the distribution station 14-i exceeds the threshold. In other words, this means that the transmission delay t of each distribution station 14-i exceeds the threshold. i Exceeded the threshold.

[0200] The real-time analysis unit 222d determines that the fourth sleep release condition (for example, U i i or T <t i ) (step S2406 is "Yes"), it is determined that the optical path needs to be switched and the dormant distribution station 14-k needs to be de-hibernated.

[0201] The real-time analysis unit 222d notifies the control unit 23 of the determination result. Then, the processing after step S406 is executed. On the other hand, if the real-time analysis unit 222d determines that the fourth sleep release condition (for example, U i i or T <t i ) (step S2406 is "No"), execute the processing of step S408.

[0202] Fig.32 1 is a sequence diagram showing an example of a detailed flow of the sleep release process executed by the mobile NW system 100d according to the fourth embodiment. Fig.32 In Figure 7 Same treatment, annotated with Figure 7 The same symbols are used and the description is omitted. Fig.32 In the description, it is assumed that the distribution station 14-2 is in a sleep state.

[0203] ​​​​The distribution station 14-2 is in a dormant state (step S501). The coordination information collecting unit 21d of the management control device 20d obtains coordination information from the distribution station 14-1 at a predetermined period (step S2501). In addition, the coordination information obtained in step S2501 includes information on the number of accommodated terminals and the maximum number of accommodated terminals, as well as information on the transmission delay between the terminal 11 and each distribution station 14. The coordination information collecting unit 21d accumulates the obtained coordination information in the coordination information accumulating unit 221.

[0204] When the cooperation information is accumulated in the cooperation information accumulation unit 221, the real-time analysis unit 222d performs the switching of the optical path and the sleep control judgment (step S2502). The switching of the optical path and the sleep control judgment in step S2502 are to determine whether the sleep release condition is satisfied. Here, it is assumed that the sleep release condition is satisfied. When the sleep release condition is satisfied, the real-time analysis unit 222d performs the processing after step S504.

[0205] According to the mobile NW system 100d constructed as described above, the same effect as that of the first embodiment can be obtained. Specifically, in the mobile NW system 100d, the management control device 20d further obtains information on the transmission delay between the terminal 11 and each distribution station 14 as cooperation information, and determines whether the optical path switching is required based on the cooperation information. When the management control device 20d determines that the optical path switching is required, it controls the switching of the optical paths between one or more wireless stations 12 and multiple distribution stations 14. In addition, after switching the optical paths, the management control device 20d causes the distribution stations that can sleep to transfer to the sleep state. Thus, while analyzing the load of each distribution station 14, the switching of the optical paths and the control of sleep are performed. Therefore, it is possible to efficiently achieve power saving as a whole system.

[0206] (Variation 1 of the Fourth Embodiment) In the above embodiment, the management control device 20d directly obtains the cooperation information from the distribution station 14. The management control device 20d may also obtain the cooperation information via other devices. Here, the other device is, for example, a wireless controller. In such a configuration, the mobile NW system 100d is newly equipped with a wireless controller 30a, and the wireless controller 30a is provided between the management control device 20d and the distribution station 14.

[0207] The wireless controller 30a obtains the cooperation information from each distribution station 14 at a predetermined period through wireless communication. The wireless controller 30a transmits the obtained cooperation information to the management control device 20d through wireless communication. In addition, the wireless controller 30a may receive a sleep control instruction from the management control device 20d and transmit it to the switching source distribution station. With this configuration, it is possible to collect cooperation information through wireless communication.

[0208] (Variation 2 of the Fourth Embodiment) In the above-mentioned embodiment, a structure is shown in which the management control device 20d performs switching control processing and sleep control processing of the optical path. In contrast, it is also possible to configure the switching device 13 to perform switching control processing and sleep control processing of the optical path. In the case of such a structure, the switching device 13 includes a control unit 23, and the management control device 20d does not include the control unit 23. The real-time analysis unit 222d of the management control device 20d notifies the switching device 13 of the analysis result. In addition, the real-time analysis unit 222d may also notify the switching device 13 of the analysis result only when switching and sleep control of the optical path are performed. The control unit 23 of the switching device 13 performs switching control processing and sleep control processing of the optical path based on the analysis result notified from the management control device 20d.

[0209] Fig.33 1 is a sequence diagram showing an example of a detailed flow of the sleep process executed by the mobile network system 100d according to the second modification of the fourth embodiment. Fig.33 In Fig.30 Same treatment, annotated with Fig.30 The same symbols are used and the description is omitted.

[0210] After executing the processes of step S2301 to step S2303, the real-time analysis unit 222d instructs the switching device 13b to switch the optical path and perform sleep control if the fourth switching condition is satisfied (step S2601). The switching device 13b receives the instruction sent from the management control device 20d.

[0211] The optical path switching control unit 231 of the switching device 13b determines the switching destination of the optical path based on the information included in the received instruction (step S2602). The optical path switching control unit 231 notifies the aggregation station 15 of the optical path switching destination information (step S2603). Thereafter, the optical path switching control unit 231 instructs the wireless station 12 connected to the switching source distribution station 14-2, the switching destination distribution station 14-1, and the switching source distribution station 14-2 to switch the optical path (step S2604). Then, the processing of steps S306 to S317 is executed.

[0212] When the optical path switching is completed, the wireless station 12 sends an optical path switching completion notification to the switching device 13b (step S2605). In addition, the wireless station 12 may also send an optical path switching completion notification to the management control device 20d. When the optical path switching is completed, the switching destination distribution station 14-1 sends an optical path switching completion notification to the switching device 13 (step S2606). In addition, the wireless station 12 may also send an optical path switching completion notification to the management control device 20d.

[0213] When the sleep control unit 232 of the switching device 13b receives the optical path switching completion notification from the destination of the optical path switching start notification, it sends a sleep permission notification to the switching source distribution station 14-2 (step S2607). When the switching source distribution station 14-2 receives the sleep permission notification from the switching device 13, it sends a sleep response notification to the switching device 13b (step S2680). After sending the sleep response notification, the switching source distribution station 14-2 transitions to the sleep state (step S322).

[0214] Fig.34 1 is a sequence diagram showing an example of a detailed flow of the sleep release process executed by the mobile NW system 100d according to the second modification of the fourth embodiment. Fig.34 In Fig.31 Same treatment, annotated with Fig.31 The same symbols are used and the description is omitted. Fig.31 In the description, it is assumed that the distribution station 14-2 is in a sleep state.

[0215] After executing the processes of step S501, step S2501 and step S2502, the real-time analyzer 222d instructs the switching device 13b to switch the optical path and perform the sleep control if the sleep release condition is satisfied (step S2701). The switching device 13b receives the instruction sent from the management control device 20d.

[0216] The sleep control unit 232 of the switching device 13b transmits a sleep release notification to the distribution station 14-2 based on the information included in the received instruction (step S2702). In response to receiving the sleep release notification, the distribution station 14-2 transmits a sleep release response notification to the switching device 13b (step S2703).

[0217] The optical path switching control unit 231 of the switching device 13b determines the switching destination of the optical path based on the information included in the received instruction (step S2704). The optical path switching control unit 231 of the switching device 13b notifies the aggregation station 15 of the optical path switching destination information (step S2705). Then, the processing from step S507 to step S520 is executed.

[0218] When the optical path switching is completed, the wireless station 12 sends an optical path switching completion notification to the switching device 13b (step S2706). When the optical path switching is completed, the distribution station 14-1 sends an optical path switching completion notification to the switching device 13b (step S2707). When the optical path switching is completed, the distribution station 14-2 sends an optical path switching completion notification to the switching device 13b (step S2708).

[0219] (Modification 1 common to the first to fourth embodiments) The mobile NW systems 100, 100a, 100c, and 100d may not include the switching device 13. In such a configuration, each wireless station 12 and each aggregation station 15 are connected in advance in a full mesh network form. Furthermore, when switching the optical path, the optical path switching control unit 231 instructs the wireless station 12 and the distribution station 14 that are the switching targets of the optical path to switch the optical path. For example, the optical path switching control unit 231 sends the switching instruction of the optical path (e.g. Figure 5 The optical path switching start notification (e.g., the processing of step S305) is sent to the wireless station 12 and the distribution station 14 that are the switching targets of the optical path. After receiving the optical path switching response notification from the wireless station 12 and the distribution station 14, the optical path switching start notification (e.g., Figure 5 The optical path is then sent to the wireless station 12 and the distribution station 14 that are the switching targets of the optical path.

[0220] (Modification 2 common to the first to fourth embodiments) In each embodiment, a structure is shown in which the switching source distribution station is transferred to the sleep state when the management control device 20, 20c, 20d issues a sleep instruction to the switching source distribution station. The switching source distribution station can also be configured to autonomously transfer to the sleep state without relying on the sleep instruction from the management control device 20, 20c, 20d. In the case of such a structure, the switching source distribution station autonomously transfers to the sleep state when the autonomous sleep condition is met. The autonomous sleep condition is a condition for the switching source distribution station to autonomously transfer to the sleep state, for example, there is no wireless station 12 connected to the device (the number of wireless stations 12 connected to the device is 0) or there is no business inflow during a certain time ΔT. In the case of such a structure, the switching source distribution station has a sleep control unit. The sleep control unit of the switching source distribution station causes the device to transfer to the sleep state when the autonomous sleep condition is met. In addition, this structure can also be applied when the control unit 23 is provided in the switching device 13b.

[0221] As information collected by the management control devices 20, 20c, and 20d, in addition to the number of accommodated terminals, the number of terminals in each distribution station 14, the number of terminals in each wireless station 12, the actual traffic volume, and the value obtained by multiplying the number of accommodated terminals by the average throughput of one terminal can be used.

[0222] At least part or all of the functional units of the management control devices 20, 20b, 20c, and 20d or part or all of the functional units of the switching devices 13 and 13b are implemented as software by executing a program stored in a storage device and a storage unit having a non-volatile recording medium (non-temporary recording medium) by a processor such as a CPU (Central Processing Unit). The program can be recorded in a computer-readable non-temporary recording medium. Examples of computer-readable non-temporary recording media include removable media such as floppy disks, magneto-optical disks, ROMs (Reader Only Memory), CD-ROMs (Compact Disc Reader Only Memory), and non-temporary recording media such as storage devices such as hard disks built into computer systems.

[0223] At least part or all of the functional units of the management control devices 20, 20b, 20c, and 20d or part or all of the functional units of the switching devices 13, 13b can also be implemented using hardware including electronic circuits (electronic circuits or circuits), such as LSI (Large Scale Integrated Circuit), ASIC (Application Specific Integrated Circuit), PLD (Programmable Logic Device) or FPGA (Field Programmable Gate Array).

[0224] As mentioned above, although the embodiment of the present invention is described in detail with reference to the drawings, the specific structure is not limited to this embodiment, and also includes the design etc. within the scope which does not deviate from the summary of the present invention.

[0225] Industrial Applicability The present invention can be applied to optical communication systems such as optical access systems.

[0226] Description of Reference Numerals 11…terminal, 12, 12-1 to 12-4…wireless station, 13, 13b…switching device, 14, 14-1 to 14-2…distribution station, 15…aggregation station, 16…core device, 20, 20b, 20c, 20d…management control device, 21, 21c, 21d…cooperative information collection unit, 21, 22…analysis unit, 23…control unit, 30a…wireless controller, 100, 100a, 100c, 100d…mobile NW system, 211…acquisition unit, 212c…distribution station monitoring unit, 213d…delay measurement unit, 221…cooperative information accumulation unit, 222…real-time analysis unit, 231…optical path switching control unit, 232…sleep control unit.

Claims

1. A communication system, wherein: have: One or more wireless stations for wireless communication with one or more terminals; a plurality of distribution stations connected to the one or more wireless stations directly or via other means; a coordination information collecting unit that obtains coordination information at a predetermined period, wherein the coordination information indicates a state of communication between the plurality of distribution stations and the one or more terminals; an optical path switching control unit that controls the switching of the optical paths between the one or more wireless stations and the plurality of distribution stations when it is determined based on the cooperation information that the switching of the optical paths between the one or more wireless stations and the plurality of distribution stations is required; as well as The sleep control unit causes the sleep-capable distribution station to shift to the sleep state after switching the optical path.

2. The communication system according to claim 1, wherein: The other device is a switching device for switching optical paths between the one or more wireless stations and the plurality of distribution stations. In the case where the switching device is provided, the optical path switching control unit instructs the switching device to switch the optical paths between the one or more wireless stations and the multiple distribution stations when it is determined based on the collaboration information that switching of the optical paths between the one or more wireless stations and the multiple distribution stations is required, The switching device switches the optical path in response to an instruction of the optical path switching control section, thereby switching the distribution station to which the one or more wireless stations are connected.

3. The communication system according to claim 1, wherein: The other device is a switching device for switching optical paths between the one or more wireless stations and the plurality of distribution stations. In the case where the switching device is provided, the switching device includes the optical path switching control unit and the sleep control unit. The optical path switching control unit receives a notification from the outside and controls the switching of the optical paths between the one or more wireless stations and the multiple distribution stations in response to the received notification, wherein the notification indicates that the switching of the optical paths between the one or more wireless stations and the multiple distribution stations is required.

4. The communication system according to any one of claims 1 to 3, wherein: The cooperation information at least includes information on the number of terminals accommodated by each distribution station and information on the maximum number of terminals accommodated by each distribution station. The method further comprises an analyzing unit, which determines that it is necessary to switch the optical path between the one or more wireless stations and the plurality of distribution stations when all the terminals accommodated by the distribution station to be determined as dormancy are accommodated in other distribution stations based on the information on the number of accommodated terminals of each distribution station and the information on the maximum number of accommodated terminals of each distribution station. The optical path switching control unit controls the switching of the optical path so that the wireless station connected to the distribution station that becomes the object of sleep determination is connected to the other distribution station. The sleep control unit shifts the distributed station that is the target of sleep determination to the sleep state as the distributed station capable of sleep.

5. The communication system according to claim 4, wherein: The cooperation information further includes at least one of processing load information related to the processing load of each distribution station, or information on transmission delay between the one or more terminals and the plurality of distribution stations. The analysis unit, based on the information on the number of terminals accommodated by each of the distribution stations, the information on the maximum number of terminals accommodated by each of the distribution stations, and the processing load information or the transmission delay information, can determine that it is necessary to switch the optical path between the one or more wireless stations and the multiple distribution stations when all the terminals accommodated by the distribution station that is the object of dormancy judgment are accommodated in other distribution stations.

6. The communication system according to claim 5, wherein: The processing load information includes information on the usage rate of the memory of each of the distribution stations.

7. A management control device, wherein: have: a cooperation information collecting unit that obtains cooperation information at a predetermined period, the cooperation information indicating the state of communication between a plurality of distribution stations and one or more terminals, the plurality of distribution stations being connected directly or via other devices to one or more wireless stations, the one or more wireless stations communicating wirelessly with the one or more terminals; an analyzing unit, which determines whether switching and sleep control of optical paths between the one or more wireless stations and the plurality of distribution stations are required based on the cooperation information; an optical path switching control unit, which controls the switching of the optical paths between the one or more wireless stations and the plurality of distribution stations when it is determined that the switching of the optical paths between the one or more wireless stations and the plurality of distribution stations is required; as well as The sleep control unit causes the sleep-capable distribution station to shift to the sleep state after switching the optical path.

8. A control method, wherein: Acquiring cooperation information at a predetermined period, the cooperation information indicating the state of communication between a plurality of distribution stations and one or more terminals, the plurality of distribution stations being connected directly or via other devices to one or more wireless stations, the one or more wireless stations communicating wirelessly with the one or more terminals; In a case where it is determined based on the cooperation information that switching of the optical paths between the one or more wireless stations and the plurality of distribution stations is required, controlling switching of the optical paths between the one or more wireless stations and the plurality of distribution stations; After the optical path is switched, the distribution station capable of sleeping is shifted to the sleeping state.

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