Communication system, management control device, communication station, and control method

Abstract

This communication system comprises: at least one terminal accommodation station that communicates with at least one terminal; a plurality of communication stations connected to the at least one terminal accommodation station directly or through another device; an association information collection unit that acquires, from the communication stations, association information indicating the state of communication between the communication stations and the at least one terminal; an optical path switching control unit that controls switching of an optical path between the at least one terminal accommodation station and the plurality of communication stations when switching of the optical path between the at least one terminal accommodation station and the plurality of communication stations is determined to be necessary on the basis of the association information; and a sleep control unit for causing a communication station, which can be set to sleep, to transition to a sleep state before or after switching of the optical path.　

Description

Communication system, management control device, communication station, and control method

[0001] This application claims priority to PCT / JP2022 / 20495, filed in Japan on May 17, 2022, the contents of which are incorporated herein by reference.

[0002] In conventional communication systems that perform wireless communication between terminals and base stations, each base station calculates its throughput and autonomously goes into sleep mode when the throughput exceeds a threshold, thereby saving power. In such communication systems, terminals connected to a sleeping base station are instructed to hand over to the base station with the highest throughput, allowing the terminal to continue communication.

[0003] Yong Sheng Soh, Tony QSQuek, and Marios Kountouris, “Dynamic Sleep Mode Strategies in Energy Efficient Cellular Networks”, IEEE, Communications Theory, pp.3131 3136, June 2013.

[0004] However, in conventional communication systems, a terminal connected to a sleeping base station may hand over to a base station already connected to a large number of terminals, resulting in a deterioration in communication quality. Furthermore, in conventional communication systems, each base station autonomously determines whether to sleep, which prevents overall optimization and potentially limits the effectiveness of power saving. Note that this problem is not limited to communication systems that perform wireless communication between terminals and each base station, but can also occur in communication systems that perform wired communication between terminals and terminal-accommodating stations that are connected to terminals by wire.

[0005] In view of the above circumstances, an object of the present invention is to provide a technique that can increase the effect of power saving without deteriorating communication quality.

[0006] One aspect of the present invention is a communication system comprising: one or more terminal accommodating stations that communicate with one or more terminals; a plurality of communication stations that are connected to the one or more terminal accommodating stations directly or via other devices; a coordination information collection unit that acquires coordination information from the communication stations indicating the state of communication between the communication 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 terminal accommodating stations and the plurality of communication stations when it is determined based on the coordination information that switching of the optical paths between the one or more terminal accommodating stations and the plurality of communication stations is necessary; and a sleep control unit that transitions communication stations that are capable of sleeping into a sleep state before or after the optical path switching is performed.

[0007] One aspect of the present invention is a management control device comprising: a communication station connected directly or via another device to one or more terminal accommodating stations that communicate with one or more terminals; a coordination information collection unit that acquires coordination information from the communication station indicating the state of communication between the one or more terminals; an analysis unit that determines whether or not optical path switching and sleep control are necessary between the one or more terminal accommodating stations and multiple communication stations based on the coordination information; an optical path switching control unit that controls the switching of optical paths between the one or more terminal accommodating stations and the multiple communication stations when it is determined that optical path switching between the one or more terminal accommodating stations and the multiple communication stations is necessary; and a sleep control unit that transitions communication stations that are capable of sleeping into a sleep state before or after the optical path switching is performed.

[0008] One aspect of the present invention is a communication station connected to a terminal accommodating station that communicates with a terminal, the communication station comprising: a transmitting unit that transmits coordination information indicating the state of communication with the terminal to a management control device; a receiving unit that receives an optical path switching instruction indicating that the management control device has determined, based on the coordination information, that it is necessary to switch the optical path between the terminal accommodating station and the communication station; and a sleep processing unit that transitions to a sleep state before or after the optical path switching based on the optical path switching instruction is performed.

[0009] One aspect of the present invention is a control method that acquires coordination information from one or more terminal accommodating stations that communicate with one or more terminals, indicating the state of communication between the one or more terminals and a communication station that is connected to the one or more terminal accommodating stations directly or via another device, and when it is determined based on the coordination information that switching of optical paths between the one or more terminal accommodating stations and multiple communication stations is necessary, controls switching of optical paths between the one or more terminal accommodating stations and the multiple communication stations, and transitions communication stations that are capable of sleeping into a sleep state before or after the switching of optical paths is performed.

[0010] According to the present invention, it is possible to increase the effect of power saving without deteriorating the communication quality.

[0011] 1 is a diagram for explaining an overview of the overall configuration and processing of a mobile NW system in an embodiment. FIG. 1 is a diagram illustrating an example of a configuration of a mobile NW system in a first embodiment. FIG. 2 is a flowchart illustrating an example of the flow of sleep processing executed by a management control device in the first embodiment. FIG. 3 is a flowchart illustrating an example of the flow of sleep processing executed by a management control device in the first embodiment. FIG. 4 is a sequence diagram illustrating an example of a detailed flow of sleep processing executed by a mobile NW system in the first embodiment. FIG. 5 is a flowchart illustrating an example of the flow of sleep release processing executed by a management control device in the first embodiment. FIG. 6 is a sequence diagram illustrating an example of a detailed flow of sleep release processing executed by a mobile NW system in the first embodiment. FIG. 7 is a diagram illustrating an example of a configuration of a mobile NW system in a modified example of the first embodiment. FIG. 8 is a diagram illustrating an example of a configuration of a mobile NW system in a modified example of the first embodiment. FIG. 9 is a sequence diagram illustrating an example of a detailed flow of sleep processing executed by a mobile NW system in a modified example of the first embodiment. FIG. 10 is a diagram illustrating an example of a configuration of a mobile NW system in a second embodiment. FIG. 11 is a flowchart illustrating an example of the flow of sleep processing executed by a management control device in the second embodiment. FIG. 12 is a sequence diagram illustrating an example of a detailed flow of sleep processing executed by a mobile NW system in the second embodiment. FIG. 10 is a flowchart showing an example of the flow of a sleep wake-up process executed by a management control device in a second embodiment; FIG. 11 is a sequence diagram showing an example of a detailed flow of a sleep wake-up process executed by a mobile NW system in a modified example of the second embodiment; FIG. 12 is a sequence diagram showing an example of a detailed flow of a sleep wake-up process executed by a mobile NW system in a modified example of the second embodiment; and FIG. 13 is a flowchart showing an example of the flow of a sleep wake-up process executed by a management control device in a third embodiment.10 is a flowchart showing an example of the flow of sleep processing executed by the management control device in the third embodiment. FIG. 11 is a sequence diagram showing an example of a detailed flow of sleep processing executed by the mobile NW system in the third embodiment. FIG. 12 is a flowchart showing an example of the flow of sleep release processing executed by the management control device in the third embodiment. FIG. 13 is a sequence diagram showing an example of a detailed flow of sleep release processing executed by the mobile NW system in the third embodiment. FIG. 14 is a sequence diagram showing an example of a detailed flow of sleep release processing executed by the mobile NW system in the third embodiment. FIG. 15 is a diagram showing an example of a configuration of a mobile NW system in the fourth embodiment. FIG. 16 is a flowchart showing an example of the flow of sleep processing executed by the management control device in the fourth embodiment. FIG. 17 is a flowchart showing an example of the flow of sleep processing executed by the management control device in the fourth embodiment. FIG. 18 is a sequence diagram showing an example of a detailed flow of sleep processing executed by the mobile NW system in the fourth embodiment. FIG. 10 is a sequence diagram showing an example of a detailed flow of a sleep wake-up process performed by a mobile NW system in a modified example of the fourth embodiment. FIG. 11 is a diagram for explaining an overview of the overall configuration and processing of a wired NW system in an embodiment. FIG. 12 is a diagram showing an example of the configuration of a wired NW system in a fifth embodiment. FIG. 13 is a flowchart showing an example of the flow of a sleep process performed by a management control device in a fifth embodiment. FIG. 14 is a flowchart showing an example of the flow of a sleep process performed by a management control device in a fifth embodiment. FIG. 15 is a sequence diagram showing an example of a detailed flow of a sleep process performed by a wired NW system in a fifth embodiment.10 is a flowchart showing an example of the flow of sleep wake-up processing executed by the management control device in the fifth embodiment. FIG. 11 is a sequence diagram showing an example of a detailed flow of sleep wake-up processing executed by the wired NW system in the fifth embodiment. FIG. 12 is a diagram showing an example of a configuration of a wired NW system in a modified example of the fifth embodiment. FIG. 13 is a diagram showing an example of a configuration of a wired NW system in the modified example of the fifth embodiment. FIG. 14 is a sequence diagram showing an example of a detailed flow of sleep wake-up processing executed by the wired NW system in the modified example of the fifth embodiment. FIG. 15 is a diagram showing an example of a configuration of a wired NW system in the sixth embodiment. FIG. 16 is a flowchart showing an example of the flow of sleep processing executed by the management control device in the sixth embodiment. FIG. 17 is a sequence diagram showing an example of a detailed flow of sleep processing executed by the wired NW system in the sixth embodiment. FIG. 18 is a flowchart showing an example of the flow of sleep wake-up processing executed by the management control device in the sixth embodiment. FIG. 19 is a sequence diagram showing an example of a detailed flow of sleep wake-up processing executed by the wired NW system in the sixth embodiment. FIG. 10 is a sequence diagram showing an example of a detailed flow of a sleep release process executed by a wired NW system in a modified example of the sixth embodiment. FIG. 11 is a flowchart showing an example of a flow of a sleep process executed by a management control device in the seventh embodiment. FIG. 12 is a flowchart showing an example of a flow of a sleep release process executed by a management control device in the seventh embodiment. FIG. 13 is a sequence diagram showing an example of a detailed flow of a sleep release process executed by a wired NW system in the seventh embodiment. FIG. 14 is a sequence diagram showing an example of a detailed flow of a sleep release process executed by a wired NW system in the seventh embodiment.10 is a sequence diagram showing an example of a detailed flow of a sleep release process executed by a wired NW system in a modified example of the seventh embodiment. FIG. 11 is a diagram showing an example of a configuration of a wired NW system in an eighth embodiment. FIG. 12 is a flowchart showing an example of a flow of a sleep process executed by a management control device in the eighth embodiment. FIG. 13 is a flowchart showing an example of a flow of a sleep release process executed by a management control device in the eighth embodiment. FIG. 14 is a sequence diagram showing an example of a detailed flow of a sleep release process executed by a wired NW system in an eighth embodiment. FIG. 15 is a sequence diagram showing an example of a detailed flow of a sleep release process executed by a wired NW system in a modified example of the eighth embodiment.

[0012] An embodiment of the present invention will be described below with reference to the drawings. (Overall Configuration and Processing Overview of a Mobile Network System) FIG. 1 is a diagram for explaining an overview of the overall configuration and processing of a mobile network system in an embodiment. First, the overall configuration of the mobile network system will be described. The mobile network system is an example of a communication system. The mobile network system is, for example, a fifth-generation mobile communication system (hereinafter referred to as "5G"). The mobile network system includes one or more radio stations 12, a switching device 13, multiple distributed stations 14, a central station 15, a core device 16, and a management control device 20.

[0013] Optical fibers that transmit optical signals are connected between the radio stations 12 and the switching device 13, between the switching device 13 and the distributed stations 14, between the distributed stations 14 and the central station 15, and between the central station 15 and the core device 16. Electrical lines or optical fibers that transmit electrical signals are connected between the switching device 13 and the management and control device 20, and between the distributed stations 14 and the management and control device 20. The example shown in Fig. 1 shows a case where there are four radio stations 12 and two distributed stations 14. Note that multiple switching devices 13 may be provided, but the following explanation will be given using a case where there is one device.

[0014] Each wireless station 12 includes one or more antennas and performs wireless communication with the terminal 11. For example, each wireless station 12 receives a signal transmitted from the terminal 11 and transmits the received signal to a remote station 14 connected via a switching device 13. Each wireless station 12 transmits the received signal to the terminal 11 via the switching device 13. The wireless station 12 is, for example, an RU (Radio Unit) in the 5G communication standard. The wireless station 12 is one aspect of a terminal accommodating station.

[0015] The switching device 13 is provided between the radio station 12 and the remote station 14. The switching device 13 switches the optical path in accordance with instructions from the management control device 20. The optical path is the route of the optical signal. The switching device 13 switches the connection between the radio station 12 and the remote station 14 by switching the optical path.

[0016] The distributed station 14 receives an uplink signal transmitted by the radio station 12 via the switching device 13. The distributed station 14 transmits a downlink signal to the radio station 12 via the switching device 13. The uplink signal is a signal transmitted by the terminal 11, and the downlink signal is a signal addressed to the terminal 11. Each distributed station 14 transitions to a sleep state in accordance with an instruction from the management control device 20. The sleep state is a state in which power saving is possible by suspending some functions. The distributed station 14 is, for example, a distributed unit (DU) in the 5G communication standard. Information that the management control device 20 acquires from the distributed station 14 is called cooperation information. The cooperation information is information indicating the state of communication between each distributed station 14 and the terminal 11. The distributed station 14 is one aspect of a communication station.

[0017] The cooperation information includes, for example, information regarding the number of terminals 11 that each distributed station 14 can accommodate (hereinafter referred to as the "number of accommodated terminals"). The cooperation information includes, for example, the maximum number of terminals that each distributed station 14 can accommodate. The maximum number of terminals that each distributed station 14 can accommodate is the maximum number of terminals that each distributed station 14 can accommodate. The cooperation information includes, for example, information regarding the radio stations 12 to which each distributed station 14 of the optical path is connected (hereinafter referred to as "connected radio station information"). The cooperation information includes, for example, information regarding the processing load of each distributed station 14 (hereinafter referred to as "processing load information"). The processing load information may be, for example, information regarding the memory usage rate of the distributed station 14 or information regarding the usage rate of the CPU (Central Processing Unit). The cooperation information includes, for example, information regarding the processing delay of each distributed station 14 (hereinafter referred to as "processing delay information"). The cooperation information includes, for example, information regarding the transmission delay between the terminal 11 and each distributed station 14 (hereinafter referred to as "delay information").

[0018] The central station 15 aggregates the uplink signals transmitted from the remote stations 14. The central station 15 distributes the downlink signals. The central station 15 is, for example, a centralized unit (CU) in the 5G communication standard.

[0019] The core device 16 performs signal processing on the upstream signals aggregated by the aggregation station 15. The core device 16 transmits signals obtained as a result of the signal processing on the upstream signals to an external network. The core device 16 receives signals from an external network.

[0020] The core device 16 performs predetermined signal processing on signals received from an external network. The core device 16 transmits signals obtained as a result of performing the signal processing on the signals received from the external network as downlink signals to the aggregation station 15. The signal processing is, for example, the transfer of user data in a User Plane Function (UPF) of the 5G core network.

[0021] The management control device 20 acquires cooperation information from the remote station 14. Based on the acquired cooperation information, the management control device 20 determines whether optical path switching and sleep control are necessary. When it is determined that optical path switching and sleep control are necessary, the management control device 20 performs optical path switching control processing and sleep control processing. The optical path switching control processing is processing to switch the optical path between the radio station 12 and the remote station 14. For example, the management control device 20 instructs the switching device 13 to control the switching of the optical path between the radio station 12 and the remote station 14. The sleep control processing is processing to put the remote station 14 into sleep mode or to release the sleep mode.

[0022] Next, an overview of the processing of the mobile network system will be explained. The upper diagram of Fig. 1 shows the connection state of the mobile network system before optical path switching, and the lower diagram of Fig. 1 shows the connection state of the mobile network system after optical path switching. The upper diagram of Fig. 1 shows an example in which radio stations 12-1 and 12-2 are connected to remote station 14-1, and radio stations 12-3 and 12-4 are connected to remote station 14-2.

[0023] The management control device 20 determines whether to perform optical path switching control processing based on the cooperation information collected from each distributed station 14. The management control device 20 determines to perform optical path switching control processing when there is a distributed station 14 that can transition to a sleep state. A distributed station 14 that can transition to a sleep state is, for example, a distributed station 14 that does not accommodate a terminal 11.

[0024] On the other hand, if there is no remote station 14 that can transition to the sleep state, the management control device 20 determines not to perform optical path switching control processing. If the management control device 20 determines to perform optical path switching control processing, it instructs the switching device 13 to switch the optical path. The switching device 13 switches the optical path between the radio station 12 and the remote station 14 in accordance with the instruction from the management control device 20. After completing the optical path switching, the switching device 13 notifies the management control device 20 of the completion of the optical path switching.

[0025] When the management control device 20 receives notification of the completion of optical path switching from the switching device 13, it transmits a sleep permission notification to the distributed station 14 that can transition to the sleep state. The sleep permission notification is a signal including an instruction to transition the distributed station 14 to the sleep state. As a result, the distributed station 14 that can transition to the sleep state transitions to the sleep state.

[0026] 1 shows an example in which wireless stations 12-1 to 12-4 are connected to distributed station 14-1 and distributed station 14-2 has transitioned to a sleep state. In this way, in the mobile NW system 100, based on cooperation information collected from each distributed station 14, a terminal 11 connected to a distributed station 14 that can transition to a sleep state is connected to another distributed station 14, thereby transitioning the distributed station 14 that can transition to a sleep state to a sleep state. Hereinafter, a distributed station 14 that can transition to a sleep state will be referred to as a "switching source distributed station," and a distributed station 14 that will be the new connection destination of the terminal 11 connected to the switching source distributed station will be referred to as a "switching destination distributed station."

[0027] (First embodiment) Fig. 2 is a diagram showing a configuration example of a mobile NW system 100 in the first embodiment. The mobile NW system 100 in the first embodiment includes one or more radio stations 12, a switching device 13, a plurality of remote stations 14, a central station 15, a core device 16, and a management and control device 20. The radio stations 12, the switching device 13, the remote stations 14, the central station 15, and the core device 16 have been described in Fig. 1 , so description thereof will be omitted. The management and control device 20 includes a cooperation information collection unit 21, an analysis unit 22, and a control unit 23.

[0028] The cooperation information collection unit 21 includes an acquisition unit 211. The acquisition unit 211 collects cooperation information from the remote stations 14 at predetermined intervals.

[0029] The analysis unit 22 includes a cooperation information storage unit 221 and a real-time analysis unit 222. The cooperation information storage unit 221 records the collected cooperation information in a predetermined storage device. The real-time analysis unit 222 analyzes the state of communication between each distributed station 14 and the terminal 11, such as the amount of change in the number of connections of the distributed station 14 per unit time, based on the cooperation information. Specifically, the real-time analysis unit 222 determines whether or not optical path switching and sleep control are required, based on the cooperation information.

[0030] For example, the real-time analysis unit 222 determines that optical path switching and sleep control are necessary when all of the terminals 11 accommodated in the source distributed station can be accommodated in another distributed station 14. In this case, the real-time analysis unit 222 notifies the control unit 23 of information indicating the distributed station 14 to which the optical path is to be switched and information indicating the distributed station 14 to be put to sleep.

[0031] For example, the real-time analysis unit 222 determines that optical path switching and sleep control are necessary when the number of terminals 11 accommodated in the distributed station 14 exceeds the maximum number of terminals that can be accommodated. In this case, the real-time analysis unit 222 notifies the control unit 23 of information indicating the distributed station 14 to which the optical path is to be switched and information indicating the distributed station 14 that is to be released from sleep.

[0032] 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 distributed node 14 to which the optical path is to be switched based on the analysis result of the real-time analysis unit 222, and instructs the switching device 13 to switch the optical path. For example, the optical path switching control unit 231 determines the distributed node 14 to which the optical path is to be switched based on information indicating the distributed node 14 to which the optical path is to be switched, which is notified by the real-time analysis unit 222.

[0033] The sleep control unit 232 causes the remote station 14 to put into sleep mode or to cancel sleep mode based on the analysis result of the real-time analysis unit 222 .

[0034] 3 is a flowchart showing an example of the flow of sleep processing executed by the management control device 20 in the first embodiment. In FIG. 3, an example is explained in which the cooperation information includes at least information on the number of terminals accommodated in each remote station 14 and information on the maximum number of terminals accommodated. The processing flow in FIG. 3 is repeatedly executed at a predetermined cycle.

[0035] The acquisition unit 211 acquires cooperation information from each remote station 14 (step S101). The acquisition unit 211 stores the acquired cooperation information for each remote station 14 in the cooperation information storage unit 221 (step S102). The real-time analysis unit 222 calculates the number of terminals that can be added to each remote station 14 based on the cooperation information for each remote station 14 stored in the cooperation information storage unit 221 (step S103). Here, the number of terminals that can be added refers to the number of terminals 11 that can be added to the remote station 14 in addition to the number of terminals that the remote station 14 currently accommodates. For example, the number of terminals that can be added can be obtained by subtracting the number of accommodated terminals from the maximum number of terminals that can be accommodated.

[0036] The real-time analysis unit 222 determines whether a first switching condition is satisfied (step S104). The first switching condition indicates that switching of the optical path between the radio station 12 and the remote station 14 is necessary, and is, for example, that the number of terminals that can be added to a certain remote station 14 is greater than the number of terminals that can be accommodated in the remote station 14 that is the target of sleep determination.

[0037] If the real-time analysis unit 222 determines that the first switching condition is satisfied (step S104—YES), it notifies the control unit 23 of an optical path switching instruction and a sleep control instruction. The optical path switching control unit 231 instructs the switching device 13 to switch the optical path of the radio station 12 connected to the source distributed station based on the optical path switching instruction notified from the real-time analysis unit 222 (step S105). Specifically, the optical path switching control unit 231 instructs the optical path of the radio station 12 connected to the source distributed station to be directed toward the destination distributed station.

[0038] The sleep control unit 232 transmits a sleep permission notification to the source distributed station (step S106). For example, the sleep control unit 232 may transmit a sleep instruction to the source distributed station when an optical path switching completion notification is received from the radio station 12 connected to the source distributed station and from the destination distributed station. The optical path switching completion notification is a signal including content indicating that the optical path switching has been completed. This allows the source distributed station to transition to a sleep state.

[0039] In the process of step S104, if the real-time analysis unit 222 determines that the first switching condition is not satisfied (step S104—NO), it determines whether or not there are other distributed stations 14 (step S107). The other distributed stations 14 are, for example, distributed stations 14 that have not been compared with the distributed station 14 that is the target of sleep determination. If the real-time analysis unit 222 determines that there are no other distributed stations 14 (step S107—NO), it ends the process.

[0040] On the other hand, if the real-time analysis unit 222 determines that there are other remote stations 14 (step S107-YES), it selects information on the number of terminals that can be added for the other remote stations 14 (step S108).The real-time analysis unit 222 executes the process of step S104 again using the information on the number of terminals that can be added for the selected other remote stations 14.

[0041] 4 is a flowchart showing an example of the flow of sleep processing executed by the management control device 20 in the first embodiment. Note that the processing shown in FIG. 4 will be described as a more specific example of the processing shown in FIG. 3.

[0042] The acquisition unit 211 acquires, from each remote station 14, the maximum number of terminals that each remote station can accommodate, information on connected radio stations, and information on the number of terminals that each remote station can accommodate, as cooperation information (step S201).

[0043] The acquisition unit 211 stores the acquired cooperation information for each distributed station 14 in the cooperation information storage unit 221 (step S202). The real-time analysis unit 222 calculates the number of additional terminals that each distributed station 14 can accommodate based on the cooperation information for each distributed station 14 stored in the cooperation information storage unit 221 (step S203). Next, the real-time analysis unit 222 assigns the value 1 to the constant i (step S204). i represents, for example, the distributed station 14-i that will be the switching destination. When i = 1, the distributed station 14-1 will be the switching destination distributed station. i has a value in the range of 1≦i≦I. I is the total number of distributed stations 14.

[0044] Next, the real-time analysis unit 222 assigns the value (i+1) to k (step S205). k represents, for example, the remote station 14-k that will be the source of switching. When k=2 (i=1), the remote station 14-2 will be the source of switching. k has a value in the range 2≦k≦K. K is the total number of remote stations 14 minus 1, that is, K=(I−1).

[0045] After that, the real-time analysis unit 222 ｉ -u ｉ >u ｋ It is determined whether or not the following is satisfied (step S206). ｉ represents the maximum number of terminals that can be accommodated by the remote station 14-i, and u ｉ represents the number of terminals accommodated in the remote station 14-i, and u ｋ represents the number of terminals accommodated in the remote station 14-k. ｉ -u ｉ >u ｋ is a specific example of the first switching condition. As an example, assume that the maximum number of terminals that the distributed station 14-1 can accommodate is 1000, the maximum number of terminals that the distributed station 14-1 can accommodate is 100, the maximum number of terminals that the distributed station 14-2 can accommodate is 800, and the maximum number of terminals that the distributed station 14-2 can accommodate is 200.

[0046] When i=1, k=2, it is expressed as follows: １ -u １ ⇒1000-100=900

[0047] Based on the above results, U １ -u １ >u ２ The real-time analysis unit 222 determines whether the first switching condition (for example, U ｉ -u ｉ >u ｋ ) is satisfied (step S206-YES), the control unit 23 is notified of an instruction to switch the optical path and an instruction to perform sleep control.

[0048] The optical path switching control unit 231 instructs the switching device 13 to switch the optical path of the radio station 12 connected to the distributed station 14-k based on the optical path switching instruction 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 radio station 12 connected to the distributed station 14-k (e.g., the distributed station 14-2) to point to the distributed station 14-i (e.g., the distributed station 14-1), which is the switching destination distributed station. The sleep control unit 232 transmits a sleep permission notification to the distributed station 14-k (e.g., the distributed station 14-2) (step S208).

[0049] On the other hand, as an example, consider a case where the maximum number of terminals accommodated in the remote station 14-1 is 1000, the maximum number of terminals accommodated in the remote station 14-1 is 500, the maximum number of terminals accommodated in the remote station 14-2 is 800, and the maximum number of terminals accommodated in the remote station 14-2 is 700. When i=1 and k=2, it is expressed as follows. U １ -u １ ⇒1000-500=500

[0050] Based on the above results, U １ -u １ >u ２ The real-time analysis unit 222 determines whether the first switching condition (for example, U ｉ -u ｉ >u ｋ If it is determined that the condition k is not satisfied (step S206--NO), it is determined whether k is the maximum value (step S209).

[0051] If the real-time analysis unit 222 determines that k is not the maximum value (step S209-NO), it adds 1 to the value of k (step S210). Thereafter, the real-time analysis unit 222 executes the process of step S206 again. For example, as in the example described above, if i=1, k=2, and k is not the maximum value, the real-time analysis unit 222 adds 1 to the value of k to make k=3. Then, the real-time analysis unit 222 calculates U １ -u １ >u ３ Determine whether or not the following is satisfied.

[0052] On the other hand, if the real-time analysis unit 222 determines that k is the maximum value (YES in step S209), it determines whether i is the maximum value (step S211). If the real-time analysis unit 222 determines that i is the maximum value (YES in step S211), it ends the process.

[0053] On the other hand, if the real-time analysis unit 222 determines that i is not the maximum value (step S211—NO), it adds 1 to the value of i (step S212). Thereafter, the real-time analysis unit 222 executes the process of step S205 again. For example, if i=1, k=3, and k is the maximum value but i is not the maximum value, the real-time analysis unit 222 adds 1 to the value of i to set it to i=2.

[0054] Then, in the process of step S205, the real-time analysis unit 222 assigns the value (i+1) to k (step S205). In this case, i=2 and k=3. After that, in the process of step S206, the real-time analysis unit 222 assigns U ２ -u ２ >u ３ Determine whether or not the following is satisfied.

[0055] 5 is a sequence diagram showing an example of a detailed flow of sleep processing executed by the mobile NW system 100 in the first embodiment. In the explanation of FIG. 5, it is assumed that the distributed station 14-1 is a switching destination distributed station and the distributed station 14-2 is a switching source distributed station. Here, the switching destination distributed station 14-1 and the switching source distributed station 14-2 are used for explanation.

[0056] The acquisition unit 211 of the management control device 20 acquires cooperation information from the switching destination remote station 14-1 and the switching source remote station 14-2 at a predetermined cycle (steps S301 and S302). The acquisition unit 211 stores the acquired cooperation information in the cooperation information storage unit 221. When the cooperation information is stored in the cooperation information storage unit 221, the real-time analysis unit 222 performs optical path switching and sleep control determination (step S303).

[0057] The optical path switching and sleep control determination in step S303 is a determination 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. If the first switching condition is satisfied, the real-time analysis unit 222 instructs the optical path switching control unit 231 to perform optical path switching control and instructs the sleep control unit 232 to perform sleep control.

[0058] 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 regarding the switching destination of the optical path. In the example shown in FIG. 5, the optical path switching destination information includes information indicating the switching destination distributed station 14-1 as the switching destination of the optical path. When the switching device 13 is notified of the optical path switching destination information from the management and control device 20, it instructs the radio station 12 connected to the switching source distributed station 14-2, the switching destination distributed station 14-1, and the switching source distributed station 14-2 to switch the optical path (step S305). For example, the switching device 13 instructs the radio station 12 connected to the switching source distributed station 14-2 to switch the optical path to the switching destination distributed station 14-1, instructs the switching destination distributed station 14-1 to switch so that an optical path is connected to the radio station 12 connected to the switching source distributed station 14-2, and instructs the switching source distributed station 14-2 not to set an optical path.

[0059] The radio station 12 connected to the switching source distributed station 14-2, the switching destination distributed station 14-1, and the switching source distributed station 14-2 prepare to switch the optical path (steps S306, S307, and S308). The radio station 12 connected to the switching source distributed station 14-2, the switching destination distributed station 14-1, and the switching source distributed station 14-2 transmit 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.

[0060] When the switching device 13 receives optical path switching response notifications from the radio stations 12 connected to the switching source distributed station 14-2, the switching destination distributed station 14-1, and the switching source distributed station 14-2, it transmits an optical path switching start notification to the radio stations 12 connected to the radio stations 12 connected to the switching source distributed station 14-2 and the switching destination distributed station 14-1 (step S312). The optical path switching start notification is a signal including a command to start switching the optical path.

[0061] The radio station 12 connected to the source distributed station 14-2 and the destination distributed station 14-1 switch their optical paths in response to receiving the optical path switching start notification (steps S313 and S314). This process switches the optical path of the radio station 12 connected to the source distributed station 14-2 so that it is directed toward the destination distributed station 14-1. That is, the radio station 12 and the destination distributed station 14-1 become capable of communicating with each other.

[0062] The destination remote station 14-1 transmits a path switching request to the core device 16 (step S315). The path switching request is a signal including a request to switch the communication path in the core device 16. The core device 16 switches the path in response to receiving the path switching request (step S316).

[0063] When the path switching is completed, the core device 16 transmits a path switching response notification to the target remote station 14-1 (step S317). The path switching response notification is a signal including information indicating that the communication path switching in the core device 16 has been completed.

[0064] When the optical path switching is completed, the radio station 12 transmits 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 optical path switching has been completed. When the optical path switching is completed, the switching destination distributed station 14-1 transmits an optical path switching completion notification to the management control device 20 (step S319).

[0065] When the sleep control unit 232 receives an optical path switching completion notification from the destination of the optical path switching start notification, it transmits a sleep permission notification to the switching source distributed station 14-2 (step S320). When the switching source distributed station 14-2 receives the sleep permission notification from the management and control device 20, it transmits a sleep response notification to the management and control device 20 (step S321). The sleep response notification is a signal including content indicating that the sleep permission notification has been received. After transmitting the sleep response notification, the switching source distributed station 14-2 transitions to a sleep state (step S322).

[0066] 6 is a flowchart showing an example of the flow of sleep release processing executed by the management control device 20 in the first embodiment. The acquisition unit 211 acquires, as cooperation information, information on the number of accommodated terminals and information on sleeping distributed stations 14-k from each distributed station 14 (step S401). The acquisition unit 211 notifies the analysis unit 22 of the acquired information on the number of accommodated terminals and information on sleeping distributed stations 14-k.

[0067] The real-time analysis unit 222 reads information on the maximum number of terminals that can be accommodated by each remote station 14 and information on the wireless stations 12 that were connected to the sleeping remote station 14-k from the cooperation information storage unit 221 (step S402).The real-time analysis unit 222 calculates the number of terminals that can be additionally accommodated by each remote station 14 based on the cooperation information for each remote station 14 stored in the cooperation information storage unit 221 (step S403).

[0068] Next, the real-time analysis unit 222 assigns the value 1 to the constant i (step S404). ｉ <u ｉ It is determined whether or not the following is satisfied (step S405). ｉ <u ｉ The condition indicated by is a specific example of the first sleep release condition. ｉ <u ｉ ) is satisfied (step S405-YES), it is determined that the sleeping remote station 14-k needs to be woken up and the optical path needs to be switched.

[0069] The real-time analysis unit 222 notifies the control unit 23 of the determination result. The sleep control unit 232 transmits an instruction to the sleeping remote station 14-k to cancel the sleep state based on the determination result (step S406). The optical path switching control unit 231 acquires information about the radio station 12 that was connected to the remote station 14-k before the sleep state from the information acquired in the processing of step S402. The optical path switching control unit 231 instructs the radio station 12 that was connected to the remote station 14-k before the sleep state to change its connection to the remote station 14-k.

[0070] In the process of step S405, the real-time analysis unit 222 determines whether the first sleep cancellation condition (for example, U ｉ <u ｉ If it is determined that the condition i is not satisfied (step S405—NO), it determines whether i is the maximum value (step S408). If it is determined that i is the maximum value (step S408—YES), the real-time analysis unit 222 ends the process.

[0071] On the other hand, if the real-time analysis unit 222 determines that i is not the maximum value (step S408—NO), it adds 1 to the value of i (step S409). Thereafter, the real-time analysis unit 222 executes the process of step S405 again.

[0072] Here, the processing in Fig. 6 will be explained using specific numerical values. As an example, it is assumed that the total number of remote stations 14 is 2 (I = 2), the maximum number of terminals that the remote station 14-1 can accommodate is 1000, the number of terminals that the remote station 14-1 can accommodate is 800, the maximum number of terminals that the remote station 14-2 can accommodate is 800, and the number of terminals that the remote station 14-2 can accommodate is 1000.

[0073] If i=1, U １ <u １ The real-time analysis unit 222 determines whether the first sleep release condition (for example, U ｉ <u ｉIf it is determined that the condition i is not satisfied (step S405-NO), it is determined whether i is the maximum value (step S408). Since i=1 at present, the real-time analysis unit 222 determines that i is not the maximum value.

[0074] The real-time analysis unit 222 adds 1 to the value of i to set it to i=2. The real-time analysis unit 222 executes the process of step S405 again. When i=2, U ２ <u ２ Since the relationship 800<1000 holds, the first sleep cancellation condition is satisfied. Then, the processes of steps S406 and S407 are executed.

[0075] 7 is a sequence diagram showing an example of a detailed flow of a sleep release process executed by the mobile network system 100 according to the first embodiment. In the explanation of FIG. 7, it is assumed that the remote station 14-2 is in a sleep state.

[0076] The remote station 14-2 is in a sleep state (step S501). The acquisition unit 211 of the management control device 20 acquires cooperation information from the remote station 14-1 at a predetermined cycle (step S502). The acquisition unit 211 stores the acquired cooperation information in the cooperation information storage unit 221. When the cooperation information is stored in the cooperation information storage unit 221, the real-time analysis unit 222 performs optical path switching and sleep control determination (step S503). The optical path switching and sleep control determination in step S503 is based on whether or not the sleep release condition is met. Here, it is assumed that the sleep release condition is met.

[0077] The sleep control unit 232 of the management control device 20 transmits a sleep release notification to the remote station 14-2 (step S504). The sleep release notification is a signal including information indicating that the sleep state is to be released. In response to receiving the sleep release notification, the remote station 14-2 transmits a sleep release response notification to the management control device 20 (step S505). The sleep release response notification is a signal including information indicating that the sleep release notification has been received.

[0078] 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 is notified of the optical path switching destination information from the management and control device 20, it instructs the radio station 12, the aggregation station 14-1, and the aggregation station 14-2 to switch the optical paths (step S507).

[0079] The radio station 12, the remote station 14-1, and the remote station 14-2 prepare to switch the optical path (steps S508, S509, and S510). When the radio station 12, the remote station 14-1, and the remote station 14-2 have completed the preparation for switching the optical path, they transmit an optical path switching response notification indicating that the preparation for switching has been completed to the switching device 13 (steps S511, S512, and S513).

[0080] When the switching device 13 receives the optical path switching response notifications from the wireless station 12, the distributed station 14-1, and the distributed station 14-2, it transmits an optical path switching start notification to the wireless station 12, the distributed station 14-1, and the distributed station 14-2 (step S514).

[0081] In response to receiving the optical path switching start notification, the radio station 12, the remote station 14-1, and the remote station 14-2 switch their optical paths (steps S515, S516, and S517). The remote station 14-1 transmits a path switching request to the core device 16 (step S518). The core device 16 switches the path in response to receiving the path switching request (step S519). When the path switching is complete, the core device 16 transmits a path switching response notification to the remote station 14-1 (step S520).

[0082] When the switching of the optical path is completed, the radio station 12 transmits an optical path switching completion notification to the management control device 20 (step S521). When the switching of the optical path is completed, the remote station 14-1 transmits an optical path switching completion notification to the management control device 20 (step S522). When the switching of the optical path is completed, the remote station 14-2 transmits an optical path switching completion notification to the management control device 20 (step S523).

[0083] The mobile network system 100 configured as described above includes one or more radio stations 12 that perform wireless communication with one or more terminals 11, multiple distributed stations 14 connected to the one or more radio stations 12 via a switching device 13, a cooperation information collector 21 that periodically acquires cooperation information indicating the state of communication between the multiple distributed stations 14 and the one or more terminals 11, an optical path switching controller 231 that controls the switching of the optical paths between the one or more radio stations 12 and the multiple distributed stations 14 when it is determined based on the cooperation information that switching of the optical paths between the one or more radio stations 12 and the multiple distributed stations 14 is necessary, and a sleep controller 232 that transitions the sleep-enabled distributed stations to a sleep state after the optical path switching is performed. This allows the optical path switching and sleep control to be performed while analyzing the load of each distributed station 14. This enables increased power saving without degrading communication quality.

[0084] (Variation 1 of First Embodiment) In the above-described embodiment, the configuration has been described in which the management control device 20 directly acquires the cooperation information from the remote station 14. The management control device 20 may acquire the cooperation information via another device. Here, the other device is, for example, a wireless controller. FIG. 8 is a diagram showing a configuration example of a mobile NW system 100a in Variation 1 of the first embodiment. The mobile NW system 100a includes one or more wireless stations 12, a switching device 13, multiple remote stations 14, a central station 15, a core device 16, a management control device 20, and a wireless controller 30a. As shown in FIG. 8, in the mobile NW system 100a, a wireless controller 30a is provided between the management control device 20 and the remote station 14.

[0085] The wireless controller 30a acquires cooperation information from each remote station 14 via wireless communication at a predetermined cycle. The wireless controller 30a transmits the acquired cooperation information to the management control device 20 via wireless communication. The wireless controller 30a may receive a sleep control instruction from the management control device 20 and transmit it to the remote station from which the switch is made. This configuration makes it possible to collect cooperation information via wireless communication.

[0086] (Variation 2 of First Embodiment) In the above-described embodiment, the configuration has been shown in which the management control device 20 performs optical path switching control processing and sleep control processing. Alternatively, the switching device 13 may be configured to perform optical path switching control processing and sleep control processing. Fig. 9 is a diagram showing an example configuration of a mobile NW system 100b in Variation 2 of the first embodiment. The mobile NW system 100b includes one or more radio stations 12, a switching device 13b, multiple distributed stations 14, a central station 15, a core device 16, and a management control device 20b.

[0087] 9, the switching device 13b includes a control unit 23, while the management control device 20b does not include a control unit 23. The real-time analysis unit 222 of the management control device 20b notifies the switching device 13b of the analysis result. Note that the real-time analysis unit 222 may notify the switching device 13b of the analysis result only when optical path switching and sleep control are performed. The control unit 23 of the switching device 13b performs optical path switching control processing and sleep control processing based on the analysis result notified from the management control device 20b.

[0088] Fig. 10 is a sequence diagram showing an example of a detailed flow of sleep processing executed by the mobile NW system 100b in Modification 2 of the first embodiment. In Fig. 10, the same processes as those in Fig. 5 are assigned the same reference numerals as those in Fig. 5, and the description thereof will be omitted. In the description of Fig. 10, the distributed station 14-1 is the target distributed station, and the distributed station 14-2 is the source distributed station. Here, the description will be given by referring to the target distributed station 14-1 and the source distributed station 14-2.

[0089] After the processes from step S301 to step S303 are executed, if the first switching condition is satisfied, the real-time analysis unit 222 instructs the switching device 13b to perform optical path switching control and sleep control (step S601). The switching device 13b receives the instructions transmitted from the management control device 20b.

[0090] The optical path switching control unit 231 of the switching device 13b determines the optical path switching destination from 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 radio station 12 connected to the switching source distributed station 14-2, the switching destination distributed station 14-1, and the switching source distributed station 14-2 to switch the optical path (step S604). Thereafter, the processes from step S306 to step S317 are executed.

[0091] When the switching of the optical path is completed, the radio station 12 transmits an optical path switching completion notification to the switching device 13b (step S605). The radio station 12 may also transmit the optical path switching completion notification to the management and control device 20b. When the switching of the optical path is completed, the switching destination distributed station 14-1 transmits an optical path switching completion notification to the switching device 13b (step S606). The radio station 12 may also transmit the optical path switching completion notification to the management and control device 20b.

[0092] When the sleep control unit 232 included in the switching device 13b receives the optical path switching completion notification from the destination of the optical path switching start notification, it transmits a sleep permission notification to the switching source distributed station 14-2 (step S607). When the switching source distributed station 14-2 receives the sleep permission notification from the switching device 13b, it transmits a sleep response notification to the switching device 13b (step S608). After transmitting the sleep response notification, the switching source distributed station 14-2 transitions to a sleep state (step S322).

[0093] 11 is a sequence diagram showing an example of a detailed flow of a sleep wake-up process executed by the mobile NW system 100b in the second modification of the first embodiment. In FIG. 11, the same processes as those in FIG. 7 are denoted by the same reference numerals as those in FIG. 7, and the description thereof will be omitted. In the description of FIG. 11, it is assumed that the remote station 14-2 is in a sleep state.

[0094] After the processes from step S501 to step S503 are executed, if the sleep release condition is satisfied, the real-time analyzer 222 instructs the switching device 13b to perform optical path switching control and sleep control (step S701). The switching device 13b receives the instructions transmitted from the management control device 20b.

[0095] The sleep control unit 232 of the switching device 13b transmits a sleep release notification to the remote station 14-2 based on the information included in the received instruction (step S702). In response to receiving the sleep release notification, the remote station 14-2 transmits a sleep release response notification to the switching device 13b (step S703).

[0096] The optical path switching control unit 231 of the switching device 13b determines the switching destination of the optical path from 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). Thereafter, the processes from step S507 to step S520 are executed.

[0097] When the optical path switching is completed, the radio station 12 transmits an optical path switching completion notice to the switching device 13b (step S706). When the optical path switching is completed, the remote station 14-1 transmits an optical path switching completion notice to the switching device 13b (step S707). When the optical path switching is completed, the remote station 14-2 transmits an optical path switching completion notice to the switching device 13b (step S708).

[0098] Second Embodiment The second embodiment differs from the first embodiment in that the cooperation information further includes processing load information (for example, information on the memory usage rate for each remote station or information on the CPU usage rate). In the second embodiment, the information on the memory usage rate for each remote station will be described as an example of the processing load information.

[0099] 12 is a diagram illustrating a configuration example of a mobile network system 100c according to the second embodiment. The mobile network system 100c according to the second embodiment includes one or more wireless stations 12, a switching device 13, a plurality of remote stations 14, a central station 15, a core device 16, and a management and control device 20c. The management and control device 20c includes a cooperation information collection unit 21c, an analysis unit 22c, and a control unit 23.

[0100] The cooperation information collection unit 21c includes an acquisition 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 analysis unit 22c as cooperation information.

[0101] The analysis unit 22c includes a cooperation information storage unit 221 and a real-time analysis unit 222c. Based on the cooperation information, the real-time analysis unit 222c analyzes the communication status in the mobile NW system 100c, such as the amount of change in the number of connections of the remote station 14 per unit time. Specifically, the real-time analysis unit 222c divides the memory usage rate by the current number of accommodated terminals to roughly estimate the memory usage rate per unit. Furthermore, the real-time analysis unit 222c multiplies the number of accommodated terminals of other remote stations 14 by the memory usage rate per unit of the target remote station 14, and determines to switch the optical path and go to sleep if the memory usage rate does not exceed 100% and the number of accommodated terminals of the remote station 14 is less than the number of terminals that the target remote station 14 can additionally accommodate.

[0102] 13 is a flowchart showing an example of the flow of sleep processing executed by the management control device 20c in the second embodiment. In Fig. 13, the same processes as those in Fig. 3 are denoted by the same reference numerals as those in Fig. 3, and the description thereof will be omitted.

[0103] The cooperation information collection unit 21c acquires cooperation information from each distributed station 14 (step S801). Specifically, the acquisition unit 211 acquires, as cooperation information, information on at least the number of accommodated terminals and information on the maximum number of accommodated terminals from each distributed station 14. Furthermore, the distributed station monitoring unit 212c measures the memory usage rate for each distributed station 14. The cooperation information collection unit 21c accumulates the acquired cooperation information for each distributed station 14 in the cooperation information storage unit 221 (step S802). Specifically, the cooperation information collection unit 21c accumulates, as cooperation information, information on the memory usage rate for each distributed station 14 in the cooperation information storage unit 221, in addition to the cooperation information including, from each distributed station 14, information on at least the number of accommodated terminals and information on the maximum number of accommodated terminals.

[0104] The real-time analysis unit 222c calculates the number of additional terminals that can be accommodated by each of the distributed stations 14 (step S803), based on the cooperation information for each of the distributed stations 14 stored in the cooperation information storage unit 221. Furthermore, the real-time analysis unit 222c estimates the memory usage rate of each of the distributed stations 14, based on the cooperation information for each of the distributed stations 14 stored in the cooperation information storage unit 221 (step S804).

[0105] The real-time analysis unit 222c determines whether a second switching condition is satisfied (step S805). The second switching condition indicates that switching of the optical path between the radio station 12 and the remote station 14 is necessary, and is, for example, that the number of terminals that can be added to a certain remote station 14 is greater than the number of terminals that can be accommodated in the remote station 14 that is the target of sleep determination, and that the memory usage rate does not exceed 100%.

[0106] If the real-time analysis unit 222c determines that the second switching condition is satisfied (step S805—YES), the process from step S105 onward is executed. On the other hand, if the real-time analysis unit 222c determines that the second switching condition is not satisfied (step S805—NO), the process from step S107 onward is executed.

[0107] Fig. 14 is a flowchart showing an example of the flow of sleep processing executed by the management control device 20c in the second embodiment. The processing shown in Fig. 14 will be described by more specifically showing the processing shown in Fig. 13. In Fig. 14, the same processes as those in Fig. 4 are assigned the same reference numerals as those in Fig. 4, and descriptions thereof will be omitted.

[0108] The acquisition unit 211 acquires, as cooperation information, the maximum number of terminals that each remote station can accommodate, information on connected radio stations, and information on the number of terminals that each remote station can accommodate, from each remote station 14. Furthermore, the remote station monitoring unit 212c acquires information on the memory usage rate of each remote station 14 (step S901).

[0109] The acquisition unit 211 stores the acquired cooperation information for each distributed station 14 in the cooperation information storage unit 221. The distributed station monitoring unit 212c stores the acquired information on the memory usage rate of each distributed station 14 as cooperation information (step S902). The real-time analysis unit 222c calculates the number of additional terminals that each distributed station 14 can accommodate, based on the cooperation information for each distributed station 14 stored in the cooperation information storage unit 221 (step S903). Furthermore, the real-time analysis unit 222c estimates the memory usage rate per distributed station 14, based on the cooperation information for each distributed station 14 stored in the cooperation information storage unit 221 (step S904).

[0110] Next, the real-time analysis unit 222c assigns the value 1 to the constant i (step S905). Next, the real-time analysis unit 222c assigns the value (i+1) to k (step S906). After that, the real-time analysis unit 222c calculates 100-M ｉ >m ｉ ×u ｋ , and U ｉ -u ｉ >u ｋ It is determined whether or not the following condition is satisfied (step S907). ｉ represents the memory usage rate of the remote station 14-i, and m ｉ represents the memory usage rate per unit of each remote station 14. ｉ is calculated in the process of step S904. ｉ >m ｉ ×u ｋ , and U ｉ -u ｉ>u ｋ The condition indicated by is a specific example of the second switching condition.

[0111] If the real-time analysis unit 222c determines that the second switching condition is satisfied (YES in step S907), it executes the processes from step S207 onward. On the other hand, if the real-time analysis unit 222c determines that the second switching condition is not satisfied (NO in step S907), it executes the processes from step S209 onward.

[0112] 14 will be described using specific numerical values. As an example, let us assume that the maximum number of terminals accommodated in the remote station 14-1 is 1000, the number of terminals accommodated in the remote station 14-1 is 100, and the memory usage rate M １ is 20%, the maximum number of terminals accommodated in the distributed station 14-2 is 800, the number of terminals accommodated in the distributed station 14-2 is 200, and the memory usage rate M ２ In this case, in the process of step S904, the real-time analysis unit 222c calculates m as an approximate value of the memory usage rate per remote station 14. １ =20 / 100=0.2,m ２ = 30 / 200 = 0.15. １ represents an approximate value of the memory usage rate per unit of the remote station 14-1, and m ２ represents an approximate value of the memory usage rate per remote station 14-2.

[0113] In the process of step S907, the real-time analysis unit 222c ｉ >m ｉ ×u ｋ , and U ｉ -u ｉ >u ｋ When i=1 and k=2, it is expressed as follows: 100-M ｉ ⇒100-20=80 ・m ｉ ×u ｋ ⇒0.2×200=40 ・U ｉ -u ｉ ⇒1000-100=900

[0114] Based on the above results, 100-Mｉ >m ｉ ×u ｋ , and U ｉ -u ｉ >u ｋ are 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 makes a switching decision to connect the radio station 12 connected to the remote station 14-2 to the remote station 14-1, and makes a sleep decision to transition the remote station 14-2 to a sleep state. The real-time analysis unit 222c notifies the optical path switching control unit 231 of the result of the switching decision to connect the radio station 12 connected to the remote station 14-2 to the remote station 14-1, and notifies the sleep control unit 232 of the result of the sleep decision to transition the remote station 14-2 to a sleep state.

[0115] As a result, the optical path switching control unit 231 controls the switching of the optical path in accordance with the notification from the real-time analysis unit 222c so as to connect the radio station 12 connected to the remote station 14-2 to the remote station 14-1. The sleep control unit 232 controls the sleep so as to transition the remote station 14-2 to a sleep state in accordance with the notification from the real-time analysis unit 222c.

[0116] Figure 15 is a sequence diagram showing an example of a detailed flow of sleep processing executed by the mobile NW system 100c in the second embodiment. In Figure 15, the same processes as those in Figure 5 are assigned the same reference numerals as in Figure 5, and descriptions thereof will be omitted. In the description of Figure 15, it is assumed that the distributed station 14-1 is the target distributed station and the distributed station 14-2 is the source distributed station. Here, the description will be given by referring to the target distributed station 14-1 and the source distributed station 14-2.

[0117] The cooperation information collection unit 21c of the management control device 20c acquires cooperation information from the switching destination remote station 14-1 and the switching source remote station 14-2 at a predetermined period (steps S1001 and S1002). Note that the cooperation information acquired in steps S1001 and S1002 includes at least information on the number of accommodated terminals, information on the maximum number of accommodated terminals, and the like, as well as information on the memory usage rate of each remote station 14. The cooperation information collection unit 21c stores the acquired cooperation information in the cooperation information storage unit 221.

[0118] When the coordination information is accumulated in the coordination information accumulation unit 221, the real-time analysis unit 222c performs optical path switching and sleep control determination (step S1003). The optical path switching and sleep control determination in step S1003 is a determination 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. If the second switching condition is satisfied, the real-time analysis unit 222c executes the processing from step S304 onwards.

[0119] 16 is a flowchart showing an example of the flow of a sleep wake-up process executed by the management control device 20c in the second embodiment. In Fig. 16, the same processes as those in Fig. 6 are denoted by the same reference numerals as those in Fig. 6, and the description thereof will be omitted.

[0120] The acquisition unit 211 acquires, as cooperation information, the number of accommodated terminals and information on sleeping distributed stations 14-k from each distributed station 14. Furthermore, the distributed station monitoring unit 212c acquires, as cooperation information, information on memory usage rates for each distributed station 14 (step S1101). The acquisition unit 211 notifies the analysis unit 22c of the acquired number of accommodated terminals, information on sleeping distributed stations 14-k, and information on memory usage rates.

[0121] The real-time analysis unit 222c of the analysis unit 22c reads information on the maximum number of terminals that can be accommodated by each remote station 14 and information on the wireless stations 12 that were connected to the sleeping remote station 14-k from the cooperation information storage unit 221 (step S1102).The real-time analysis unit 222c calculates the number of terminals that can be additionally accommodated by each remote station 14 based on the obtained cooperation information for each remote station 14 (step S1103).

[0122] Next, the real-time analysis unit 222c assigns the value 1 to the constant i (step S1104). ｉ <u ｉ , or T1<M ｉ It is determined whether any one of the following conditions is satisfied (step S1105). ｉ <u ｉ , or T1<M ｉ The condition shown in is a specific example of the second sleep wake-up condition. ｉ is the memory usage rate M of the remote station 14-i. ｉ exceeds a threshold T1 (for example, a predetermined value such as 80, 90, or 100%).

[0123] The real-time analysis unit 222c determines whether a second sleep cancellation condition (e.g., U ｉ <u ｉ , or T1<M ｉ ) is satisfied (step S1105-YES), it is determined that the optical path needs to be switched and the sleeping remote station 14-k needs to be woken up.

[0124] The real-time analysis unit 222c notifies the control unit 23 of the determination result. Then, the processes from step S406 onward are executed. Meanwhile, the real-time analysis unit 222c determines whether the second sleep cancellation condition (for example, U ｉ <u ｉ , or T1<M ｉ ) is not satisfied (step S1105-NO), the process of step S408 is executed.

[0125] 17 is a sequence diagram showing an example of a detailed flow of a sleep release process executed by the mobile network system 100c in the second embodiment. In FIG. 17, the same processes as those in FIG. 7 are denoted by the same reference numerals as those in FIG. 7, and the description thereof will be omitted. In the description of FIG. 17, it is assumed that the remote station 14-2 is in a sleep state.

[0126] The remote station 14-2 is in a sleep state (step S501). The cooperation information collection unit 21c of the management control device 20c acquires cooperation information from the remote station 14-1 at a predetermined cycle (step S1201). Note that the cooperation information acquired in step S1201 includes information on at least the number of accommodated terminals, information on the maximum number of accommodated terminals, and the like, as well as information on the memory usage rate for each remote station 14. The cooperation information collection unit 21c stores the acquired cooperation information in the cooperation information storage unit 221.

[0127] When the cooperation information is accumulated in the cooperation information accumulation unit 221, the real-time analysis unit 222c performs optical path switching and sleep control determination (step S1202). The optical path switching and sleep control determination in step S1202 is based on whether the sleep cancellation condition is satisfied. Here, it is assumed that the sleep cancellation condition is satisfied. If the sleep cancellation condition is satisfied, the real-time analysis unit 222c executes the processing from step S504 onwards.

[0128] The mobile network system 100c of the second embodiment configured as described above can achieve the same effects as those of the first embodiment. Specifically, in the mobile network system 100c, the management and control device 20c further acquires information on the memory usage rate of each remote station 14 as cooperation information and determines whether or not an optical path switching is necessary based on the cooperation information. When it is determined that an optical path switching is necessary, the management and control device 20c controls the switching of the optical paths between one or more radio stations 12 and multiple remote stations 14. Furthermore, after the optical path switching is performed, the management and control device 20c transitions the remote stations that can sleep to a sleep state. This allows the management and control device 20c to control the switching of the optical paths and the sleep state while analyzing the load of each remote station 14. This makes it possible to increase the power saving effect without degrading communication quality.

[0129] (Variation 1 of the Second Embodiment) In the above-described embodiment, the configuration has been described in which the management control device 20c directly acquires the cooperation information from the remote station 14. The management control device 20c may acquire the cooperation information via another device. Here, the other device is, for example, a wireless controller. In such a configuration, the mobile NW system 100c newly includes a wireless controller 30a, and the wireless controller 30a is provided between the management control device 20c and the remote station 14.

[0130] The wireless controller 30a acquires cooperation information from each remote station 14 via wireless communication at a predetermined cycle. The wireless controller 30a transmits the acquired cooperation information to the management control device 20c via wireless communication. The wireless controller 30a may receive a sleep control instruction from the management control device 20c and transmit it to the remote station from which the switch is made. This configuration makes it possible to collect cooperation information via wireless communication.

[0131] (Variation 2 of Second Embodiment) In the above-described embodiment, the configuration has been shown in which the management control device 20c performs optical path switching control processing and sleep control processing. In contrast, the switching device 13 may be configured to perform optical path switching control processing and sleep control processing. In such a configuration, the switching device 13 includes a control unit 23, and the management control device 20c does not include a control unit 23. The real-time analysis unit 222c of the management control device 20c notifies the switching device 13 of the analysis result. Note that the real-time analysis unit 222c may notify the switching device 13 of the analysis result only when optical path switching and sleep control are performed. The control unit 23 of the switching device 13 performs optical path switching control processing and sleep control processing based on the analysis result notified from the management control device 20c.

[0132] 18 is a sequence diagram showing an example of a detailed flow of a sleep process executed by the mobile NW system 100c in Modification 2 of the second embodiment. In Fig. 18, the same processes as those in Fig. 15 are denoted by the same reference numerals as those in Fig. 15, and the description thereof will be omitted.

[0133] After the processes from step S1001 to step S1003 are executed, if the second switching condition is satisfied, the real-time analysis unit 222c instructs the switching device 13b to perform optical path switching control and sleep control (step S1301). The switching device 13b receives the instructions transmitted from the management control device 20c.

[0134] The optical path switching control unit 231 of the switching device 13b determines the optical path switching destination from 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 radio station 12 connected to the switching source distributed station 14-2, the switching destination distributed station 14-1, and the switching source distributed station 14-2 to switch the optical path (step S1304). Thereafter, the processes from step S306 to step S317 are executed.

[0135] When the switching of the optical path is completed, the radio station 12 transmits an optical path switching completion notification to the switching device 13b (step S1305). The radio station 12 may also transmit the optical path switching completion notification to the management and control device 20c. When the switching of the optical path is completed, the switching destination distributed station 14-1 transmits an optical path switching completion notification to the switching device 13 (step S1306). The radio station 12 may also transmit the optical path switching completion notification to the management and control device 20c.

[0136] When the sleep control unit 232 included in the switching device 13b receives the optical path switching completion notification from the destination of the optical path switching start notification, it transmits a sleep permission notification to the switching source distributed station 14-2 (step S1307). When the switching source distributed station 14-2 receives the sleep permission notification from the switching device 13, it transmits a sleep response notification to the switching device 13b (step S1308). After transmitting the sleep response notification, the switching source distributed station 14-2 transitions to a sleep state (step S322).

[0137] 19 is a sequence diagram showing an example of a detailed flow of a sleep release process executed by the mobile NW system 100c in the second modification of the second embodiment. In FIG. 19, the same processes as those in FIG. 17 are denoted by the same reference numerals as those in FIG. 17, and the description thereof will be omitted. In the description of FIG. 17, it is assumed that the remote station 14-2 is in a sleep state.

[0138] After the processes of steps S501, S1201, and S1202 are executed, if the sleep release condition is satisfied, the real-time analysis unit 222c instructs the switching device 13b to perform optical path switching control and sleep control (step S1401). The switching device 13b receives the instructions transmitted from the management control device 20c.

[0139] The sleep control unit 232 of the switching device 13b transmits a sleep release notification to the remote station 14-2 based on the information included in the received instruction (step S1402). In response to receiving the sleep release notification, the remote station 14-2 transmits a sleep release response notification to the switching device 13b (step S1403).

[0140] The optical path switching control unit 231 of the switching device 13b determines the switching destination of the optical path from 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). Thereafter, the processes from step S507 to step S520 are executed.

[0141] When the switching of the optical path is completed, the radio station 12 transmits an optical path switching completion notice to the switching device 13b (step S1406). When the switching of the optical path is completed, the remote station 14-1 transmits an optical path switching completion notice to the switching device 13b (step S1407). When the switching of the optical path is completed, the remote station 14-2 transmits an optical path switching completion notice to the switching device 13b (step S1408).

[0142] (Third Embodiment) In the third embodiment, the configuration differs from that of the second embodiment in that the cooperation information further includes processing load information (for example, information on memory usage rate for each remote station or information on CPU usage rate) and processing delay information for each remote station. Note that the system configuration is the same as that of the second embodiment. In the third embodiment, information on memory usage rate for each remote station will be described as an example of processing load information.

[0143] The management control device 20c determines optical path switching and sleep based on information on the number of terminals for each distributed station 14, information on the memory usage rate for each distributed station 14, and processing delay information for each distributed station 14. For example, the distributed station monitoring unit 212c monitors each distributed station 14 and measures the memory usage rate for each distributed station 14. Furthermore, the distributed station monitoring unit 212c monitors each distributed station 14 and collects processing delay information for each distributed station 14. The distributed station monitoring unit 212c outputs the information on the memory usage rate measured for each distributed station 14 and the processing delay information for each distributed station 14 to the analysis unit 22c as collaboration information.

[0144] 20 is a flowchart showing an example of the flow of sleep processing executed by the management control device 20c in the third embodiment. In Fig. 20, the same processes as those in Fig. 13 are denoted by the same reference numerals as in Fig. 13, and the description thereof will be omitted.

[0145] The cooperation information collection unit 21c acquires cooperation information from each distributed station 14 (step S1501). Specifically, the acquisition unit 211 acquires, as cooperation information, from each distributed station 14, information on at least the number of accommodated terminals and information on the maximum number of accommodated terminals. Furthermore, the distributed station monitoring unit 212c measures the memory usage rate for each distributed station 14 and acquires processing delay information for each distributed station 14. The cooperation information collection unit 21c accumulates the acquired cooperation information for each distributed station 14 in the cooperation information storage unit 221 (step S1502). Specifically, the cooperation information collection unit 21c accumulates, as cooperation information, information on the memory usage rate for each distributed station 14 and the processing delay information for each distributed station 14 in the cooperation information storage unit 221, in addition to the cooperation information including, from each distributed station 14, information on at least the number of accommodated terminals and information on the maximum number of accommodated terminals.

[0146] The real-time analysis unit 222c calculates the number of additional terminals that can be accommodated by each of the distributed stations 14 based on the cooperation information for each of the distributed stations 14 stored in the cooperation information storage unit 221 (step S1503). Furthermore, the real-time analysis unit 222c estimates the memory usage rate of each of the distributed stations 14 based on the cooperation information for each of the distributed stations 14 stored in the cooperation information storage unit 221 (step S1504).

[0147] The real-time analysis unit 222c determines whether a third switching condition is satisfied (step S1505). The third switching condition is a condition indicating that switching of the optical path between the radio station 12 and the remote station 14 is necessary, and is, for example, that the number of terminals that can be added to a certain remote station 14 is greater than the number of terminals that can be accommodated in the remote station 14 that is the target of sleep determination, that the memory usage rate does not exceed 100%, and that the processing delay of the remote station 14 that is the target of sleep determination does not exceed a threshold.

[0148] If the real-time analysis unit 222c determines that the third switching condition is satisfied (step S1505—YES), the process proceeds to step S105. On the other hand, if the real-time analysis unit 222c determines that the third switching condition is not satisfied (step S1505—NO), the process proceeds to step S107.

[0149] Fig. 21 is a flowchart showing an example of the flow of sleep processing executed by the management control device 20c in the third embodiment. Note that the processing shown in Fig. 21 will be described by more specifically showing the processing shown in Fig. 20. In Fig. 21, processing that is the same as that in Fig. 14 is assigned the same reference numerals as in Fig. 14, and description thereof will be omitted.

[0150] The acquisition unit 211 acquires, as cooperation information, the maximum number of terminals that each remote station can accommodate, information on connected radio stations, and information on the number of terminals that each remote station can accommodate, from each remote station 14. Furthermore, the remote station monitoring unit 212c acquires information on the memory usage rate and processing delay information of each remote station 14 (step S1601).

[0151] The acquisition unit 211 stores the acquired cooperation information for each distributed station 14 in the cooperation information storage unit 221. Furthermore, the distributed station monitoring unit 212c stores the acquired memory usage rate information and processing delay information for each distributed station 14 as cooperation information (step S1602). The real-time analysis unit 222c calculates the number of additional terminals that each distributed station 14 can accommodate, based on the cooperation information for each distributed station 14 stored in the cooperation information storage unit 221 (step S1603). Furthermore, the real-time analysis unit 222c estimates the memory usage rate per distributed station 14, based on the cooperation information for each distributed station 14 stored in the cooperation information storage unit 221 (step S1604).

[0152] Next, the real-time analysis unit 222c assigns the value 1 to the constant i (step S1605). Next, the real-time analysis unit 222c assigns the value (i+1) to k (step S1606). After that, the real-time analysis unit 222c calculates 100-M ｉ >m ｉ ×u ｋ , and U ｉ -u ｉ >u ｋ , and T>t ｉ It is determined whether or not T satisfies the threshold value (step S1607). ｉ represents the processing delay of the remote station 14-i. ｉ >m ｉ ×u ｋ , and U ｉ -u ｉ >u ｋ , and T>t ｉ The condition indicated by is a specific example of the third switching condition.

[0153] If the real-time analysis unit 222c determines that the third switching condition is satisfied (YES in step S1607), it executes the processes from step S207 onward. On the other hand, if the real-time analysis unit 222c determines that the third switching condition is not satisfied (NO in step S1607), it executes the processes from step S209 onward.

[0154] Figure 22 is a sequence diagram showing an example of a detailed flow of sleep processing executed by the mobile NW system 100c in the third embodiment. In Figure 22, the same processes as those in Figure 15 are assigned the same reference numerals as those in Figure 15, and their description will be omitted. In the description of Figure 22, it is assumed that the distributed station 14-1 is the target distributed station and the distributed station 14-2 is the original distributed station. Here, the description will be given by referring to the target distributed station 14-1 and the original distributed station 14-2.

[0155] The cooperation information collection unit 21c of the management control device 20c acquires cooperation information from the switching destination remote station 14-1 and the switching source remote station 14-2 at a predetermined period (steps S1701 and S1702). Note that the cooperation information acquired in steps S1701 and S1702 includes at least information on the number of accommodated terminals, information on the maximum number of accommodated terminals, etc., as well as information on the memory usage rate of each remote station 14 and processing delay information for each remote station 14. The cooperation information collection unit 21c stores the acquired cooperation information in the cooperation information storage unit 221.

[0156] When the cooperation information is accumulated in the cooperation information accumulation unit 221, the real-time analysis unit 222c performs optical path switching and sleep control determination (step S1703). The optical path switching and sleep control determination in step S1703 is a determination 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. If the fifth switching condition is satisfied, the real-time analysis unit 222c executes the processing from step S304 onwards.

[0157] 23 is a flowchart showing an example of the flow of a sleep release process executed by the management control device 20c in the third embodiment. In Fig. 23, the same processes as those in Fig. 16 are denoted by the same reference numerals as in Fig. 16, and the description thereof will be omitted.

[0158] The acquisition unit 211 acquires, as cooperation information, the number of accommodated terminals and information on sleeping distributed stations 14-k from each distributed station 14. Furthermore, the distributed station monitoring unit 212c acquires, as cooperation information, information on memory usage rate for each distributed station 14 and processing delay information for each distributed station 14 (step S1751). The acquisition unit 211 notifies the analysis unit 22c of the acquired number of accommodated terminals, information on sleeping distributed stations 14-k, information on memory usage rate, and processing delay information for each distributed station 14.

[0159] The real-time analysis unit 222c of the analysis unit 22c reads information on the maximum number of terminals that can be accommodated by each remote station 14 and information on the wireless stations 12 that were connected to the sleeping remote station 14-k from the cooperation information accumulation unit 221 (step S1752).The real-time analysis unit 222c calculates the number of terminals that can be additionally accommodated by each remote station 14 based on the obtained cooperation information for each remote station 14 (step S1753).

[0160] Next, the real-time analysis unit 222c assigns the value 1 to the constant i (step S1754). ｉ <u ｉ , or T1<M ｉ , or T<t ｉ It is determined whether any one of the following conditions is satisfied (step S1755). ｉ <u ｉ , or T1<M ｉ , or T<t ｉ The condition shown in is a specific example of the third sleep wake-up condition. ｉ means that the processing delay of the remote station 14-i has exceeded the threshold.

[0161] The real-time analysis unit 222c determines whether a third sleep cancellation condition (e.g., U ｉ <u ｉ , or T1<M ｉ , or T<t ｉ ) is satisfied (step S1755-YES), it is determined that it is necessary to switch the optical path and to wake up the sleeping remote station 14-k.

[0162] The real-time analysis unit 222c notifies the control unit 23 of the determination result. Then, the processing from step S406 onward is executed. On the other hand, the real-time analysis unit 222c determines whether the third sleep cancellation condition (for example, U ｉ <u ｉ , or T1<M ｉ , or T<t ｉ ) is not satisfied (step S1755--NO), the process of step S408 is executed.

[0163] 24 is a sequence diagram showing an example of a detailed flow of a sleep release process executed by the mobile NW system 100c in the third embodiment. In FIG. 24, the same processes as those in FIG. 17 are denoted by the same reference numerals as those in FIG. 17, and the description thereof will be omitted. In the description of FIG. 17, it is assumed that the remote station 14-2 is in a sleep state.

[0164] The remote station 14-2 is in a sleep state (step S501). The cooperation information collection unit 21c of the management control device 20c acquires cooperation information from the remote station 14-1 at a predetermined cycle (step S1801). It is assumed that the cooperation information acquired in step S1801 includes information on memory usage rates and processing delay information for each remote station 14. The cooperation information collection unit 21c stores the acquired cooperation information in the cooperation information storage unit 221.

[0165] When the cooperation information is accumulated in the cooperation information accumulation unit 221, the real-time analysis unit 222c performs optical path switching and sleep control determination (step S1802). The optical path switching and sleep control determination in step S1802 is based on whether the sleep cancellation condition is satisfied. Here, it is assumed that the sleep cancellation condition is satisfied. If the sleep cancellation condition is satisfied, the real-time analysis unit 222c executes the processing from step S504 onwards.

[0166] The mobile network system 100c according to the third embodiment configured as described above can achieve the same effects as those of the first embodiment. Specifically, in the mobile network system 100c according to the third embodiment, the management and control device 20c further acquires, as cooperation information, information on the memory usage rate of each remote station 14 and information on the processing delay of each remote station 14, and determines whether or not an optical path switching is necessary based on the cooperation information. When it is determined that an optical path switching is necessary, the management and control device 20c controls the switching of the optical paths between one or more radio stations 12 and the multiple remote stations 14. Furthermore, after the optical path switching is performed, the management and control device 20c transitions the remote stations capable of sleeping to a sleep state. As a result, the optical path switching and sleep control are performed while analyzing the load of each remote station 14. This makes it possible to increase the power saving effect without degrading communication quality.

[0167] (Variation 1 of the Third Embodiment) In the above-described embodiment, the configuration has been described in which the management control device 20c directly acquires the cooperation information from the remote station 14. The management control device 20c may acquire the cooperation information via another device. Here, the other device is, for example, a wireless controller. In such a configuration, the mobile NW system 100c newly includes a wireless controller 30a, and the wireless controller 30a is provided between the management control device 20c and the remote station 14.

[0168] The wireless controller 30a acquires cooperation information from each remote station 14 via wireless communication at a predetermined cycle. The wireless controller 30a transmits the acquired cooperation information to the management control device 20c via wireless communication. The wireless controller 30a may receive a sleep control instruction from the management control device 20c and transmit it to the remote station from which the switch is made. This configuration makes it possible to collect cooperation information via wireless communication.

[0169] (Variation 2 of Third Embodiment) In the above-described embodiment, the configuration has been shown in which the management control device 20c performs optical path switching control processing and sleep control processing. In contrast, the switching device 13 may be configured to perform optical path switching control processing and sleep control processing. In such a configuration, the switching device 13 includes a control unit 23, and the management control device 20c does not include a control unit 23. The real-time analysis unit 222c of the management control device 20c notifies the switching device 13 of the analysis result. Note that the real-time analysis unit 222c may notify the switching device 13 of the analysis result only when optical path switching and sleep control are performed. The control unit 23 of the switching device 13 performs optical path switching control processing and sleep control processing based on the analysis result notified from the management control device 20c.

[0170] 25 is a sequence diagram showing an example of a detailed flow of a sleep process executed by the mobile NW system 100c in Modification 2 of the third embodiment. In FIG. 25, the same processes as those in FIG. 22 are denoted by the same reference numerals as those in FIG. 22, and the description thereof will be omitted.

[0171] After the processes from step S1701 to step S1703 are executed, if the third switching condition is satisfied, the real-time analysis unit 222c instructs the switching device 13b to perform optical path switching control and sleep control (step S1901). The switching device 13b receives the instructions transmitted from the management control device 20c.

[0172] The optical path switching control unit 231 of the switching device 13b determines the optical path switching destination from 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 radio station 12 connected to the switching source distributed station 14-2, the switching destination distributed station 14-1, and the switching source distributed station 14-2 to switch the optical path (step S1904). Thereafter, the processes from step S306 to step S317 are executed.

[0173] When the switching of the optical path is completed, the radio station 12 transmits an optical path switching completion notification to the switching device 13b (step S1905). The radio station 12 may also transmit the optical path switching completion notification to the management and control device 20c. When the switching of the optical path is completed, the switching destination distributed station 14-1 transmits an optical path switching completion notification to the switching device 13 (step S1906). The radio station 12 may also transmit the optical path switching completion notification to the management and control device 20c.

[0174] When the sleep control unit 232 included in the switching device 13b receives the optical path switching completion notification from the destination of the optical path switching start notification, it transmits a sleep permission notification to the switching source distributed station 14-2 (step S1907). When the switching source distributed station 14-2 receives the sleep permission notification from the switching device 13, it transmits a sleep response notification to the switching device 13b (step S1908). After transmitting the sleep response notification, the switching source distributed station 14-2 transitions to a sleep state (step S322).

[0175] 26 is a sequence diagram showing an example of a detailed flow of a sleep wake-up process executed by the mobile NW system 100c in Modification 2 of the third embodiment. In Fig. 26, the same processes as those in Fig. 23 are denoted by the same reference numerals as those in Fig. 23, and the description thereof will be omitted.

[0176] After the processes of steps S501, S1801, and S1802 are executed, if the sleep release condition is satisfied, the real-time analysis unit 222c instructs the switching device 13b to perform optical path switching control and sleep control (step S2001). The switching device 13b receives the instructions transmitted from the management control device 20c.

[0177] The sleep control unit 232 of the switching device 13b transmits a sleep release notification to the remote station 14-2 based on the information included in the received instruction (step S2002). In response to receiving the sleep release notification, the remote station 14-2 transmits a sleep release response notification to the switching device 13b (step S2003).

[0178] The optical path switching control unit 231 of the switching device 13b determines the switching destination of the optical path from 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). Thereafter, the processes from step S507 to step S520 are executed.

[0179] When the switching of the optical path is completed, the radio station 12 transmits an optical path switching completion notice to the switching device 13b (step S2006). When the switching of the optical path is completed, the remote station 14-1 transmits an optical path switching completion notice to the switching device 13b (step S2007). When the switching of the optical path is completed, the remote station 14-2 transmits an optical path switching completion notice to the switching device 13b (step S2008).

[0180] Fourth Embodiment The fourth embodiment differs from the first embodiment in that the cooperation information further includes information on transmission delays between the terminal 11 and each remote station 14 .

[0181] 27 is a diagram illustrating a configuration example of a mobile NW system 100d according to the 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 remote stations 14, a central station 15, a core device 16, and a management and control device 20d. The management and control device 20d includes a cooperation information collection unit 21d, an analysis unit 22d, and a control unit 23.

[0182] The cooperation information collection unit 21d includes an acquisition unit 211 and a delay measurement unit 213d. The delay measurement unit 213d measures the transmission delay between the terminal 11 and each remote station 14. For example, the delay measurement unit 213d measures the transmission delay between the terminal 11 and each remote station 14 based on a round-trip time (RTT) obtained as a result of transmitting a Ping. The delay measurement unit 213d outputs information on the propagation delay measured for each remote station 14 to the analysis unit 22d as cooperation information.

[0183] The analysis unit 22d includes a cooperation information storage unit 221 and a real-time analysis unit 222d. Based on the cooperation information, the real-time analysis unit 222d analyzes the communication status in the mobile NW system 100d, such as the amount of change in the number of connections of the remote station 14 per unit time. Specifically, the real-time analysis unit 222d divides the delay time by the number of currently accommodated terminals to estimate the delay time per unit. Furthermore, the real-time analysis unit 222d multiplies the number of accommodated terminals in other remote stations 14 by the delay time per unit of the target remote station 14, and determines to switch the optical path and go to sleep if the delay time does not exceed a threshold and the number of accommodated terminals in the remote station 14 is less than the number of terminals that the target remote station 14 can additionally accommodate.

[0184] 28 is a flowchart showing an example of the flow of sleep processing executed by the management control device 20d in the fourth embodiment. In Fig. 28, the same processes as those in Fig. 3 are denoted by the same reference numerals as in Fig. 3, and the description thereof will be omitted.

[0185] The delay measurement unit 213d measures the transmission delay between the terminal 11 and each remote station 14 (step S2101). The cooperation information collection unit 21d acquires cooperation information from each remote station 14 (step S2102). Specifically, the acquisition unit 211 acquires, as cooperation information, information on at least the number of accommodated terminals and information on the maximum number of accommodated terminals from each remote station 14. The cooperation information collection unit 21d accumulates the acquired cooperation information for each remote station 14 in the cooperation information storage unit 221 (step S2103). Specifically, the cooperation information collection unit 21d accumulates, as cooperation information, information on the transmission delay between the terminal 11 and each remote station 14 in the cooperation information storage unit 221, in addition to the cooperation information including, from each remote station 14, information on at least the number of accommodated terminals and information on the maximum number of accommodated terminals.

[0186] The real-time analysis unit 222d calculates the number of terminals that can be added to each distributed station 14 based on the cooperation information for each distributed station 14 stored in the cooperation information storage unit 221 (step S2104). Furthermore, the real-time analysis unit 222d estimates the delay time of each distributed station 14 based on the information on the transmission delay between the terminal 11 and each distributed station 14 stored in the cooperation information storage unit 221 (step S2105).

[0187] The real-time analysis unit 222d determines whether a fourth switching condition is satisfied (step S2106). The fourth switching condition indicates that switching of the optical path between the radio station 12 and the remote station 14 is necessary, and is, for example, that the number of terminals that can be added to a certain remote station 14 is greater than the number of terminals that can be accommodated in the remote station 14 that is the target of sleep determination, and that the transmission delay does not exceed a threshold.

[0188] If the real-time analysis unit 222d determines that the fourth switching condition is satisfied (step S2106—YES), the process from step S105 onward is executed. On the other hand, if the real-time analysis unit 222d determines that the second switching condition is not satisfied (step S2106—NO), the process from step S107 onward is executed.

[0189] Fig. 29 is a flowchart showing an example of the flow of sleep processing executed by the management control device 20d in the fourth embodiment. Note that the processing shown in Fig. 29 will be described by more specifically showing the processing shown in Fig. 28. In Fig. 29, the same processing as in Fig. 4 is assigned the same reference numerals as in Fig. 4, and description thereof will be omitted.

[0190] The delay measurement unit 213d measures a transmission delay between the terminal 11 and each remote station 14 (step S2201). The acquisition unit 211 acquires, from each remote station 14, the maximum number of terminals that each remote station can accommodate, connected radio station information, and information on the number of terminals that each remote station can accommodate, as cooperation information (step S2202).

[0191] The acquisition unit 211 stores the acquired cooperation information for each distributed station 14 in the cooperation information storage unit 221 (step S2203). The real-time analysis unit 222d calculates the number of additional terminals that each distributed station 14 can accommodate, based on the cooperation information for each distributed station 14 stored in the cooperation information storage unit 221 (step S2204). Furthermore, the real-time analysis unit 222d estimates the transmission delay per distributed station 14, based on information about the measured transmission delay between the terminal 11 and each distributed station 14 (step S2205).

[0192] Specifically, the real-time analysis unit 222d calculates the transmission delay value T of the remote station 14-i obtained in the process of step S2201. ｉThe number of terminals accommodated in the remote station 14-i is u ｉ Divide by (T ｉ / u ｉ ) by reducing the transmission delay t ｉ Next, the real-time analysis unit 222d assigns the value 1 to the constant i (step S2206). Next, the real-time analysis unit 222d assigns the value (i+1) to k (step S2207).

[0193] After that, the real-time analysis unit 222d ｉ -u ｉ >u ｋ , and T>t ｉ × (u ｉ +u ｋ ) is satisfied (step S2208). ｉ is the transmission delay t per remote station 14-i ｉ Represents U ｉ -u ｉ >u ｋ , and T>t ｉ × (u ｉ +u ｋ ) is a specific example of the fourth switching condition. If the real-time analysis unit 222d determines that the fourth switching condition is satisfied (step S2208—YES), it executes the processes from step S207 onwards. On the other hand, if the real-time analysis unit 222d determines that the second switching condition is not satisfied (step S2208—NO), it executes the processes from step S209 onwards.

[0194] Fig. 30 is a sequence diagram showing an example of a detailed flow of sleep processing executed by the mobile NW system 100d in the fourth embodiment. In Fig. 30, the same processes as those in Fig. 5 are assigned the same reference numerals as those in Fig. 5, and the description thereof will be omitted. In the description of Fig. 30, it is assumed that the distributed station 14-1 is the target distributed station and the distributed station 14-2 is the source distributed station. Here, the description will be given by referring to the target distributed station 14-1 and the source distributed station 14-2.

[0195] The cooperation information collection unit 21d of the management control device 20d acquires cooperation information from the switching destination remote station 14-1 and the switching source remote station 14-2 at a predetermined period (steps S2301 and S2302). Note that the cooperation information acquired in steps S2301 and S2302 includes at least information on the number of accommodated terminals, information on the maximum number of accommodated terminals, and the like, as well as information on transmission delays between the terminal 11 and each remote station 14. The cooperation information collection unit 21d stores the acquired cooperation information in the cooperation information storage unit 221.

[0196] When the cooperation information is accumulated in the cooperation information accumulation unit 221, the real-time analysis unit 222d performs optical path switching and sleep control determination (step S2303). The optical path switching and sleep control determination in step S2303 is a determination 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. If the fourth switching condition is satisfied, the real-time analysis unit 222d executes the processing from step S304 onwards.

[0197] 31 is a flowchart showing an example of the flow of a sleep release process executed by the management control device 20d in the fourth embodiment. In Fig. 31, the same processes as those in Fig. 6 are denoted by the same reference numerals as in Fig. 6, and the description thereof will be omitted.

[0198] The delay measurement unit 213d measures the transmission delay between the terminal 11 and each remote station 14 (step S2401). The acquisition unit 211 acquires, as cooperation information, the number of accommodated terminals and information on sleeping remote stations 14-k from each remote station 14 (step S2402). The acquisition unit 211 notifies the analysis unit 22d of the acquired number of accommodated terminals, information on sleeping remote stations 14-k, and information on transmission delay.

[0199] The real-time analysis unit 222d of the analysis unit 22d reads information on the maximum number of terminals that can be accommodated by each remote station 14 and information on the wireless stations 12 that were connected to the sleeping remote station 14-k from the cooperation information storage unit 221 (step S2403).The real-time analysis unit 222d calculates the number of terminals that can be additionally accommodated by each remote station 14 based on the obtained cooperation information for each remote station 14 (step S2404).

[0200] Next, the real-time analysis unit 222d assigns the value 1 to the constant i (step S2405). ｉ <u ｉ , or T<t ｉ It is determined whether any one of the following conditions is satisfied (step S2406). ｉ <u ｉ , or T<t ｉ The condition shown in is a specific example of the fourth sleep cancellation condition. ｉ means that the transmission delay between the terminal 11 and the remote station 14-i exceeds the threshold. That is, the transmission delay t ｉ means that the threshold has been exceeded.

[0201] The real-time analysis unit 222d determines whether a fourth sleep cancellation condition (e.g., U ｉ <u ｉ , or T<t ｉ ) is satisfied (step S2406-YES), it is determined that the optical path needs to be switched and the sleeping remote station 14-k needs to be woken up.

[0202] The real-time analysis unit 222d notifies the control unit 23 of the determination result. Then, the processes from step S406 onward are executed. On the other hand, the real-time analysis unit 222d determines whether the fourth sleep cancellation condition (for example, U ｉ <u ｉ , or T<t ｉ ) is not satisfied (step S2406--NO), the process of step S408 is executed.

[0203] 32 is a sequence diagram showing an example of a detailed flow of a sleep release process executed by the mobile NW system 100d in the fourth embodiment. In FIG. 32, the same processes as those in FIG. 7 are denoted by the same reference numerals as those in FIG. 7, and the description thereof will be omitted. In the description of FIG. 32, it is assumed that the remote station 14-2 is in a sleep state.

[0204] The remote station 14-2 is in a sleep state (step S501). The cooperation information collection unit 21d of the management control device 20d acquires cooperation information from the remote station 14-1 at a predetermined cycle (step S2501). Note that the cooperation information acquired in step S2501 includes information on at least the number of accommodated terminals, information on the maximum number of accommodated terminals, and the like, as well as information on transmission delays between the terminal 11 and each remote station 14. The cooperation information collection unit 21d stores the acquired cooperation information in the cooperation information storage unit 221.

[0205] When the cooperation information is accumulated in the cooperation information accumulation unit 221, the real-time analysis unit 222d performs optical path switching and sleep control determination (step S2502). The optical path switching and sleep control determination in step S2502 is based on whether the sleep cancellation condition is satisfied. Here, it is assumed that the sleep cancellation condition is satisfied. If the sleep cancellation condition is satisfied, the real-time analysis unit 222d executes the processing from step S504 onwards.

[0206] The mobile NW system 100d configured as described above can achieve the same effects as those of the first embodiment. Specifically, in the mobile NW system 100d, the management and control device 20d further acquires information on transmission delays between the terminal 11 and each remote station 14 as cooperation information and determines whether or not an optical path switching is necessary based on the cooperation information. When it is determined that an optical path switching is necessary, the management and control device 20d controls the optical path switching between one or more radio stations 12 and the multiple remote stations 14. Furthermore, after the optical path switching is performed, the management and control device 20d transitions the remote stations that can sleep to a sleep state. As a result, the optical path switching and sleep are controlled while analyzing the load of each remote station 14. Therefore, it is possible to efficiently achieve power saving throughout the entire system.

[0207] (Variation 1 of the Fourth Embodiment) In the above-described embodiment, the configuration has been described in which the management control device 20d directly acquires the cooperation information from the remote station 14. The management control device 20d may acquire the cooperation information via another device. Here, the other device is, for example, a wireless controller. In such a configuration, the mobile NW system 100d newly includes a wireless controller 30a, and the wireless controller 30a is provided between the management control device 20d and the remote station 14.

[0208] The wireless controller 30a acquires cooperation information from each remote station 14 via wireless communication at a predetermined cycle. The wireless controller 30a transmits the acquired cooperation information to the management control device 20d via wireless communication. The wireless controller 30a may receive a sleep control instruction from the management control device 20d and transmit it to the remote station from which the switch is made. This configuration makes it possible to collect cooperation information via wireless communication.

[0209] (Variation 2 of Fourth Embodiment) In the above-described embodiment, the configuration has been shown in which the management control device 20d performs optical path switching control processing and sleep control processing. In contrast, the switching device 13 may be configured to perform optical path switching control processing and sleep control processing. In such a configuration, the switching device 13 includes a control unit 23, and the management control device 20d does not include a control unit 23. The real-time analysis unit 222d of the management control device 20d notifies the switching device 13 of the analysis result. Note that the real-time analysis unit 222d may notify the switching device 13 of the analysis result only when optical path switching and sleep control are performed. The control unit 23 of the switching device 13 performs optical path switching control processing and sleep control processing based on the analysis result notified from the management control device 20d.

[0210] 33 is a sequence diagram showing an example of a detailed flow of sleep processing executed by the mobile NW system 100d in Modification 2 of the fourth embodiment. In Fig. 33, the same processes as those in Fig. 30 are denoted by the same reference numerals as those in Fig. 30, and descriptions thereof will be omitted.

[0211] After the processes from step S2301 to step S2303 are executed, if the fourth switching condition is satisfied, the real-time analysis unit 222d instructs the switching device 13b to perform optical path switching control and sleep control (step S2601). The switching device 13b receives the instructions transmitted from the management control device 20d.

[0212] The optical path switching control unit 231 of the switching device 13b determines the optical path switching destination from 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 radio station 12 connected to the switching source distributed station 14-2, the switching destination distributed station 14-1, and the switching source distributed station 14-2 to switch the optical path (step S2604). Thereafter, the processes from step S306 to step S317 are executed.

[0213] When the switching of the optical path is completed, the radio station 12 transmits an optical path switching completion notification to the switching device 13b (step S2605). The radio station 12 may also transmit the optical path switching completion notification to the management and control device 20d. When the switching of the optical path is completed, the switching destination distributed station 14-1 transmits an optical path switching completion notification to the switching device 13 (step S2606). The radio station 12 may also transmit the optical path switching completion notification to the management and control device 20d.

[0214] When the sleep control unit 232 included in the switching device 13b receives the optical path switching completion notification from the destination of the optical path switching start notification, it transmits a sleep permission notification to the switching source distributed station 14-2 (step S2607). When the switching source distributed station 14-2 receives the sleep permission notification from the switching device 13, it transmits a sleep response notification to the switching device 13b (step S2608). After transmitting the sleep response notification, the switching source distributed station 14-2 transitions to a sleep state (step S322).

[0215] 34 is a sequence diagram showing an example of a detailed flow of a sleep release process executed by the mobile NW system 100d in the second modification of the fourth embodiment. In FIG. 34, the same processes as those in FIG. 31 are denoted by the same reference numerals as those in FIG. 31, and the description thereof will be omitted. In the description of FIG. 31, it is assumed that the remote station 14-2 is in a sleep state.

[0216] After the processes of steps S501, S2501, and S2502 are executed, if the sleep release condition is satisfied, the real-time analysis unit 222d instructs the switching device 13b to perform optical path switching control and sleep control (step S2701). The switching device 13b receives the instructions transmitted from the management control device 20d.

[0217] The sleep control unit 232 of the switching device 13b transmits a sleep release notification to the remote station 14-2 based on the information included in the received instruction (step S2702). In response to receiving the sleep release notification, the remote station 14-2 transmits a sleep release response notification to the switching device 13b (step S2703).

[0218] The optical path switching control unit 231 of the switching device 13b determines the switching destination of the optical path from 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). Thereafter, the processes from step S507 to step S520 are executed.

[0219] When the optical path switching is completed, the radio station 12 transmits an optical path switching completion notice to the switching device 13b (step S2706). When the optical path switching is completed, the remote station 14-1 transmits an optical path switching completion notice to the switching device 13b (step S2707). When the optical path switching is completed, the remote station 14-2 transmits an optical path switching completion notice to the switching device 13b (step S2708).

[0220] (Variation 1 common to the first to fourth embodiments) The mobile network systems 100, 100a, 100c, and 100d may not include the switching device 13. In this configuration, each radio station 12 and each remote station 14 are connected in advance in a full-mesh network configuration. Furthermore, when switching an optical path, the optical path switching control unit 231 instructs the radio station 12 and the remote station 14 that are targets of optical path switching to switch the optical path. For example, the optical path switching control unit 231 transmits an optical path switching instruction (e.g., the process of step S305 in FIG. 5 ) to the radio station 12 and the remote station 14 that are targets of optical path switching, and after receiving an optical path switching response notification from the radio station 12 and the remote station 14, transmits an optical path switching start notification (e.g., the process of step S312 in FIG. 5 ) to the radio station 12 and the remote station 14 that are targets of optical path switching.

[0221] (Variation 2 Common to the First to Fourth Embodiments) In each embodiment, the configuration has been described in which the former distributed station transitions to a sleep state when the management and control devices 20, 20c, and 20d issue a sleep instruction to the former distributed station. The former distributed station may be configured to transition to a sleep state autonomously, regardless of a sleep instruction from the management and control devices 20, 20c, and 20d. In this configuration, the former distributed station transitions to a sleep state autonomously when an autonomous sleep condition is satisfied. The autonomous sleep condition is a condition for the former distributed station to transition to a sleep state autonomously, such as no wireless stations 12 being connected to the former distributed station (no wireless stations 12 being connected to the former distributed station) or no traffic flowing in for a certain period of time ΔT. In this configuration, the former distributed station includes a sleep control unit. The sleep control unit included in the former distributed station transitions its own device (the former distributed station) to a sleep state when the autonomous sleep condition is satisfied. Note that this configuration is also applicable when the switching device 13b includes the control unit 23.

[0222] (Variant 3 common to the first to fourth embodiments) In addition to the number of accommodated terminals, the information collected by the management control devices 20, 20c, and 20d can also include the number of terminals in each remote station 14, the number of terminals in each radio station 12, the actual traffic volume, and the value obtained by multiplying the number of accommodated terminals by the average throughput of one terminal.

[0223] (Modification 4 common to the first to fourth embodiments) In each of the embodiments shown in the first to fourth embodiments, a configuration has been shown in which the distributed station 14 to be put to sleep (e.g., the switching source distributed station) is put to sleep after the optical path switching is completed in Figures 3, 4, 5, 10, 13, 14, 15, 18, 20, 21, 22, 25, 28, 29, 30, and 33. Specifically, a configuration has been shown in which the management and control devices 20, 20b, 20c, and 20d put the distributed station 14 to be put to sleep (e.g., the switching source distributed station) to sleep after the optical path switching is completed (e.g., after receiving an optical path switching completion notification).

[0224] In contrast to this, the mobile NW systems 100, 100a, 100b, 100c, and 100d in Figures 3, 4, 5, 10, 13, 14, 15, 18, 20, 21, 22, 25, 28, 29, 30, and 33 may be configured to switch the optical path after putting the remote station 14 to be put to sleep (e.g., the switching source remote station) to sleep. When configured in this way, the management and control devices 20, 20b, 20c, and 20d execute switching of the optical path after putting the remote station 14 to be put to sleep (e.g., the switching source remote station) to sleep. Here, "after putting the distributed station 14 to be put to sleep (e.g., the source distributed station) to sleep" may mean after the management control devices 20, 20b, 20c, 20d receive a sleep response notification from the distributed station 14 to be put to sleep (e.g., the source distributed station), or may mean after sending a sleep permission notification to the distributed station 14 to be put to sleep (e.g., the source distributed station).

[0225] (Fifth Embodiment) In the first to fourth embodiments described above, configurations for solving problems that arise in mobile network systems have been described. Specifically, in the first to fourth embodiments, configurations for solving a problem that occurs in a mobile network system in which wireless communication is performed between a terminal and each base station, each base station autonomously determines whether or not to sleep, which may prevent overall optimization and result in limited power-saving effects. However, such problems are not limited to mobile network systems, but may also occur in wired network systems in which terminals are connected via wires. Therefore, in the fifth embodiment, a configuration for solving the above problems that may also occur in wired network systems will be described.

[0226] (Overall configuration and processing overview of wired network system) FIG. 35 is a diagram for explaining an overview of the overall configuration and processing of a wired network system in an embodiment. First, the overall configuration of the wired network system will be explained. The wired network system is an example of a communication system. The wired network system is, for example, a PON (Passive Optical Network). In the following explanation, a case where the wired network system is a PON will be explained, but the wired network system may have other configurations as long as terminals are connected by wire. For example, the wired network system may have a configuration in which terminals are connected point-to-point. The wired network system includes one or more ONUs 42, a switching device 43, multiple OLTs 44, a concentrator 45, a core device 46, and a management control device 50.

[0227] Optical fibers that transmit optical signals are connected between the ONUs 42 and the switching devices 43, between the switching devices 43 and the OLT 44, between the OLT 44 and the concentrator 45, and between the concentrator 45 and the core device 46. Electrical lines or optical fibers that transmit electrical signals are connected between the switching devices 43 and the management control device 50, and between the OLT 44 and the management control device 50. The example shown in Figure 35 shows a case where there are four ONUs 42 and two OLTs 44. Note that multiple switching devices 43 may be provided, but the following explanation will be given taking the case where there is one device as an example.

[0228] The ONUs 42 are optical subscriber line terminals provided in user premises that terminate optical signals. One or more terminals 41 are connected to each ONU 42 via wires such as electrical wires. Each ONU 42 performs wired communication with the terminals 41. For example, each ONU 42 receives an electrical signal transmitted from the terminal 41 and converts the received electrical signal into an optical signal. Each ONU 42 transmits the converted optical signal to the OLT 44 connected via a switching device 43. Each ONU 42 receives the optical signal via the switching device 43. Each ONU 42 converts the received optical signal into an electrical signal and transmits it to the terminal 41. The ONU 42 is one aspect of a terminal accommodation station.

[0229] The switching device 43 is provided between the ONU 42 and the OLT 44. The switching device 43 switches the optical path in accordance with an instruction from the management control device 50. The switching device 43 switches the connection between the ONU 42 and the OLT 44 by switching the optical path.

[0230] The OLT 44 is an optical line termination provided on the electric utility side and terminates optical signals. The OLT 44 receives upstream signals transmitted by the ONUs 42 via the switching device 43. The OLT 44 transmits downstream signals to the ONUs 42 via the switching device 43. The upstream signals are signals transmitted by the terminals 41 converted into optical signals, and the downstream signals are optical signals addressed to the terminals 41. Each OLT 44 transitions to a sleep state in accordance with instructions from the management control device 50. Information acquired by the management control device 50 from the OLT 44 is called coordination information. The coordination information in the fifth to eighth embodiments described below is information indicating the state of communication between each OLT 44 and the terminals 41. The OLT 44 is one aspect of a communication station.

[0231] The coordination information includes, for example, information regarding the number of accommodated terminals. Note that, in the fifth to eighth embodiments, the information regarding the number of accommodated terminals represents information regarding the number of terminals 41 accommodated per OLT 44. The coordination information includes, for example, the maximum number of terminals accommodated per OLT 44. The maximum number of terminals accommodated per OLT 44 is the maximum number of terminals that the OLT 44 can accommodate. The coordination information includes, for example, information regarding the ONUs 42 connected to the OLT 44 of the optical path (hereinafter referred to as "connected ONU information"). The coordination information includes, for example, processing load information. Note that, in the fifth to eighth embodiments, the processing load information is information regarding the processing load of the OLT 44, and may be, for example, information regarding the memory usage rate or the CPU usage rate of the OLT 44. The coordination information includes, for example, processing delay information. Note that, in the fifth to eighth embodiments, the processing delay information represents information regarding the processing delay for each OLT 44. The coordination information includes, for example, delay information. Note that, in the fifth to eighth embodiments, the delay information represents information regarding the transmission delay between the terminal 41 and each OLT 44.

[0232] The OLT 44 includes at least a transmitter, a receiver, and a sleep processor. The transmitter transmits coordination information to the management controller 50 either upon request from the management controller 50 or independently. The receiver receives an optical path switching instruction from the management controller 50. The OLT 44 receiving an optical path switching instruction from the management controller 50 indicates that the management controller 50 has determined, based on the coordination information, that it is necessary to switch the optical path between the ONU 42 and the OLT 44. The sleep processor transitions to a sleep state after the optical path is switched based on the optical path switching instruction. Furthermore, the OLT 44 includes an optical path switching processor for performing optical path switching processing.

[0233] The concentrator 45 aggregates the upstream signals transmitted by the OLTs 44. The concentrator 45 distributes the downstream signals.

[0234] The core device 46 performs signal processing on the upstream signals aggregated by the concentrator 45. The concentrator 45 transmits the signals obtained as a result of the signal processing performed on the upstream signals to an external network. The core device 46 receives signals from the external network.

[0235] The core device 46 performs predetermined signal processing on signals received from an external network, and transmits the signals obtained as a result of the signal processing performed on the signals received from the external network to the concentrator 45 as downstream signals.

[0236] The management control device 50 acquires cooperation information from the OLT 44. The management control device 50 determines whether optical path switching and sleep control are necessary based on the acquired cooperation information. When it is determined that optical path switching and sleep control are necessary, the management control device 50 performs optical path switching control processing and sleep control processing. The optical path switching control processing in the fifth to eighth embodiments is processing for switching the optical path between the ONU 42 and the OLT 44. For example, the management control device 50 instructs the switching device 43 to control the switching of the optical path between the ONU 42 and the OLT 44. The sleep control processing in the fifth to eighth embodiments is processing for executing sleep for the OLT 44 or canceling sleep.

[0237] Next, an overview of the processing of the wired network system will be explained. The upper diagram of Fig. 35 shows the connection state of the wired network system before optical path switching, and the lower diagram of Fig. 35 shows the connection state of the wired network system after optical path switching. The upper diagram of Fig. 35 shows an example in which ONUs 42-1 and 42-2 are connected to OLT 44-1, and ONUs 42-3 and 42-4 are connected to OLT 44-2.

[0238] The management control device 50 determines whether to perform optical path switching control processing based on the coordination information collected from each OLT 44. The management control device 50 determines to perform optical path switching control processing when there is an OLT 44 that can transition to a sleep state. An OLT 44 that can transition to a sleep state is, for example, an OLT 44 that does not accommodate a terminal 41.

[0239] On the other hand, if there is no OLT 44 that can transition to a sleep state, the management control device 50 determines not to perform optical path switching control processing. If the management control device 50 determines to perform optical path switching control processing, it instructs the switching device 43 to switch the optical path. The switching device 43 switches the optical path between the ONU 42 and the OLT 44 in accordance with the instruction from the management control device 50. After completing the optical path switching, the switching device 43 notifies the management control device 50 of the completion of the optical path switching.

[0240] When the management control device 50 receives a notification of completion of optical path switching from the switching device 43, it transmits a sleep permission notification to the OLT 44 that can transition to a sleep state. The sleep permission notification in the fifth to eighth embodiments is a signal that includes an instruction to transition the OLT 44 to a sleep state. As a result, the OLT 44 that can transition to a sleep state transitions to the sleep state.

[0241] The lower diagram of Figure 35 shows an example in which ONUs 42-1 to 42-4 are connected to OLT 44-1 and OLT 44-2 has transitioned to a sleep state. In this way, in a wired network system, based on the coordination information collected from each OLT 44, a terminal 41 connected to an OLT 44 capable of transitioning to a sleep state is connected to another OLT 44, thereby transitioning the OLT 44 capable of transitioning to a sleep state to a sleep state. Hereinafter, an OLT 44 capable of transitioning to a sleep state will be referred to as a switching source OLT, and an OLT 44 that will be the new connection destination of a terminal 41 connected to the switching source OLT will be referred to as a switching destination OLT. Specific configurations will be described below using the fifth to eighth embodiments as examples.

[0242] Fifth Embodiment Fig. 36 is a diagram showing an example of the configuration of a wired network system 200 according to a fifth embodiment. The wired network system 200 according to the fifth embodiment includes one or more ONUs 42, a switching device 43, a plurality of OLTs 44, a concentrator 45, a core device 46, and a management control device 50. The ONUs 42, the switching device 43, the OLTs 44, the concentrator 45, and the core device 46 have been described in Fig. 35 , and therefore further description thereof will be omitted. The management control device 50 includes a collaboration information collection unit 51, an analysis unit 52, and a control unit 53.

[0243] The linkage information collection unit 51 includes an acquisition unit 511. The acquisition unit 511 collects linkage information from the OLT 44 at a predetermined interval or at an arbitrary timing. The arbitrary timing may be, for example, when a predetermined time arrives or when an instruction to collect linkage information is input to the management control device 50 from outside.

[0244] The analysis unit 52 includes a linkage information storage unit 521 and a real-time analysis unit 522. The linkage information storage unit 521 records the collected linkage information in a predetermined storage device. The real-time analysis unit 522 analyzes the state of communication between each OLT 44 and the terminal 41, such as the amount of change in the number of connections of the OLT 44 per unit time, based on the linkage information. Specifically, the real-time analysis unit 522 determines whether or not optical path switching and sleep control are required, based on the linkage information.

[0245] For example, the real-time analysis unit 522 determines that optical path switching and sleep control are necessary when all terminals 41 accommodated in the switching source OLT can be accommodated in another OLT 44. In this case, the real-time analysis unit 522 notifies the control unit 53 of information indicating the OLT 44 to which the optical path is switched and information indicating the OLT 44 to be put into sleep mode.

[0246] For example, the real-time analysis unit 522 determines that optical path switching and sleep control are necessary when the number of terminals 41 accommodated by the OLT 44 exceeds the maximum number of terminals that can be accommodated. In this case, the real-time analysis unit 522 notifies the control unit 53 of information indicating the OLT 44 to which the optical path is to be switched and information indicating the OLT 44 to be subject to sleep cancellation.

[0247] The control unit 53 includes an optical path switching control unit 531 and a sleep control unit 532. The optical path switching control unit 531 determines the OLT 44 to which the optical path is to be switched based on the analysis result of the real-time analysis unit 522, and instructs the switching device 43 to switch the optical path. For example, the optical path switching control unit 531 determines the OLT 44 to which the optical path is to be switched based on information indicating the OLT 44 to which the optical path is to be switched, which is notified from the real-time analysis unit 522.

[0248] The sleep control unit 532 causes the OLT 44 to put into sleep mode or to cancel sleep mode based on the results of the analysis by the real-time analysis unit 522 .

[0249] Fig. 37 is a flowchart showing an example of the flow of sleep processing executed by the management control device 50 in the fifth embodiment. Fig. 37 illustrates an example in which the cooperation information includes at least information on the number of terminals accommodated in each OLT 44 and information on the maximum number of terminals accommodated. The processing flow in Fig. 37 is repeatedly executed at a predetermined cycle.

[0250] The acquisition unit 511 acquires cooperation information from each OLT 44 (step Sa101). The acquisition unit 511 stores the acquired cooperation information for each OLT 44 in the cooperation information storage unit 521 (step Sa102). The real-time analysis unit 522 calculates the number of additional terminals that can be accommodated for each OLT 44 based on the cooperation information for each OLT 44 stored in the cooperation information storage unit 521 (step Sa103). Here, the number of additional terminals that can be accommodated refers to the number of terminals 41 that can be additionally accommodated in addition to the number of terminals currently accommodated by the OLT 44. For example, the number of additional terminals that can be accommodated can be obtained by subtracting the number of accommodated terminals from the maximum number of accommodated terminals.

[0251] The real-time analysis unit 522 determines whether a fifth switching condition is satisfied (step Sa104). The fifth switching condition is a condition indicating that switching of the optical path between the ONU 42 and the OLT 44 is necessary, such as the number of terminals that can be added to a certain OLT 44 being greater than the number of terminals that can be accommodated by the OLT 44 that is the target of sleep determination.

[0252] If the real-time analysis unit 522 determines that the fifth switching condition is satisfied (step Sa104—YES), it notifies the control unit 53 of an optical path switching instruction and a sleep control instruction. The optical path switching control unit 531 instructs the switching device 43 to switch the optical path of the ONU 42 connected to the switching source OLT based on the optical path switching instruction notified from the real-time analysis unit 522 (step Sa105). Specifically, the optical path switching control unit 531 instructs the optical path of the ONU 42 connected to the switching source OLT to be directed to the switching destination OLT.

[0253] The sleep control unit 532 transmits a sleep permission notification to the switching source OLT (step Sa106). For example, the sleep control unit 532 may transmit a sleep instruction to the switching source OLT when an optical path switching completion notification is received from the ONU 42 connected to the switching source OLT and the switching destination OLT. This allows the switching source OLT to transition to a sleep state.

[0254] In the processing of step Sa104, if the real-time analysis unit 522 determines that the fifth switching condition is not satisfied (step Sa104—NO), it determines whether or not there are other OLTs 44 (step Sa107). The other OLTs 44 are, for example, OLTs 44 that have not been compared with the OLT 44 that is the target of sleep determination. If the real-time analysis unit 522 determines that there are no other OLTs 44 (step Sa107—NO), it ends the processing.

[0255] On the other hand, if the real-time analysis unit 522 determines that there is another OLT 44 (step Sa107—YES), it selects information on the number of terminals that can be added to the other OLT 44 (step Sa108). The real-time analysis unit 522 executes the process of step Sa104 again using the information on the number of terminals that can be added to the other OLT 44 that has been selected.

[0256] 38 is a flowchart showing an example of the flow of sleep processing executed by the management control device 50 in the fifth embodiment. Note that the processing shown in FIG. 38 will be described as a more specific example of the processing shown in FIG. 37.

[0257] The acquisition unit 511 acquires, from each OLT 44, the maximum number of terminals that can be accommodated in each OLT 44, connected ONU information, and information on the number of terminals that can be accommodated in each OLT 44 as cooperation information (step Sa201).

[0258] The acquisition unit 511 accumulates the acquired association information for each OLT 44 in the association information accumulation unit 521 (step Sa202). The real-time analysis unit 522 calculates the number of additional terminals that each OLT 44 can accommodate based on the association information for each OLT 44 accumulated in the association information accumulation unit 521 (step Sa203). Next, the real-time analysis unit 522 assigns a value of 1 to the constant i (step Sa204). In the fifth to eighth embodiments, i represents, for example, the OLT 44-i that is the switching destination. When i=1, OLT 44-1 is the switching destination OLT. i has a value in the range of 1≦i≦I. I is the total number of OLTs 44.

[0259] Next, the real-time analysis unit 522 assigns the value of (i+1) to k (step Sa205). In the fifth to eighth embodiments, k represents, for example, the OLT 44-k that is the switching source. When k=2 (i=1), OLT 44-2 becomes the switching source OLT. k has a value in the range of 2≦k≦K. K is the total number of OLTs 44 minus 1, that is, K=(I−1).

[0260] After that, the real-time analysis unit 522 ｉ -u ｉ >u ｋ In the fifth to eighth embodiments, it is determined whether U ｉ represents the maximum number of terminals accommodated in the OLT 44-i, and in the fifth to eighth embodiments, u ｉ represents the number of terminals accommodated in the OLT 44-i, and in the fifth to eighth embodiments, u ｋ represents the number of terminals accommodated in the OLT 44-k. ｉ -u ｉ >u ｋ is a specific example of the fifth switching condition. As an example, it is assumed that the maximum number of terminals that can be accommodated in OLT 44-1 is 1000, the number of terminals that can be accommodated in OLT 44-1 is 100, the maximum number of terminals that can be accommodated in OLT 44-2 is 800, and the number of terminals that can be accommodated in OLT 44-2 is 200.

[0261] When i=1, k=2, it is expressed as follows: １ -u １⇒1000-100=900

[0262] Based on the above results, U １ -u １ >u ２ The real-time analysis unit 522 determines whether the fifth switching condition (for example, U ｉ -u ｉ >u ｋ ) is satisfied (step Sa206-YES), the control unit 53 is notified of an instruction to switch the optical path and an instruction to perform sleep control.

[0263] The optical path switching control unit 531 instructs the switching device 43 to switch the optical path of the ONU 42 connected to the OLT 44-k based on the optical path switching instruction notified from the real-time analysis unit 522 (step Sa207). Specifically, the optical path switching control unit 531 instructs the optical path of the ONU 42 connected to the OLT 44-k (e.g., OLT 44-2) to be directed to the switching destination OLT, OLT 44-i (e.g., OLT 44-1). The sleep control unit 532 transmits a sleep permission notification to the OLT 44-k (e.g., OLT 44-2) (step Sa208).

[0264] On the other hand, as an example, consider a case where the maximum number of terminals accommodated in OLT 44-1 is 1000, the number of terminals accommodated in OLT 44-1 is 500, the maximum number of terminals accommodated in OLT 44-2 is 800, and the number of terminals accommodated in OLT 44-2 is 700. When i=1 and k=2, it is expressed as follows. U １ -u １ ⇒1000-500=500

[0265] Based on the above results, U １ -u １ >u ２ The real-time analysis unit 522 determines whether the fifth switching condition (for example, U ｉ -u ｉ >u ｋ If it is determined that the condition k is not satisfied (step Sa206-NO), it is determined whether k is the maximum value (step Sa209).

[0266] If the real-time analysis unit 522 determines that k is not the maximum value (step Sa209-NO), it adds 1 to the value of k (step Sa210). Thereafter, the real-time analysis unit 522 executes the process of step Sa206 again. For example, as in the example described above, if i=1, k=2, and k is not the maximum value, the real-time analysis unit 522 adds 1 to the value of k to make k=3. Then, the real-time analysis unit 522 executes the process of step Sa206 again. １ -u １ >u ３ Determine whether or not the following is satisfied.

[0267] On the other hand, if the real-time analysis unit 522 determines that k is the maximum value (YES in step Sa209), it determines whether i is the maximum value (step Sa211). If the real-time analysis unit 522 determines that i is the maximum value (YES in step Sa211), it ends the process.

[0268] On the other hand, if the real-time analysis unit 522 determines that i is not the maximum value (step Sa211—NO), it adds 1 to the value of i (step Sa212). Thereafter, the real-time analysis unit 522 executes the process of step Sa205 again. For example, if i=1, k=3, and k is the maximum value but i is not the maximum value, the real-time analysis unit 522 adds 1 to the value of i to set i=2.

[0269] Then, in the process of step Sa205, the real-time analysis unit 522 assigns the value (i+1) to k (step Sa205). In this case, i=2 and k=3. Thereafter, in the process of step Sa206, the real-time analysis unit 522 assigns U ２ -u ２ >u ３ Determine whether or not the following is satisfied.

[0270] 39 is a sequence diagram showing an example of a detailed flow of sleep processing executed by the wired network system 200 in the fifth embodiment. In the explanation of FIG. 39, it is assumed that the OLT 44-1 is the switching destination OLT and the OLT 44-2 is the switching source OLT. Here, the explanation will be given by referring to the switching destination OLT 44-1 and the switching source OLT 44-2.

[0271] The acquisition unit 511 of the management control device 50 acquires cooperation information from the switching destination OLT 44-1 and the switching source OLT 44-2 at a predetermined cycle or at any timing (steps Sa301 and Sa302). The acquisition unit 511 stores the acquired cooperation information in the cooperation information storage unit 521. When the cooperation information is stored in the cooperation information storage unit 521, the real-time analysis unit 522 performs optical path switching and sleep control determination (step Sa303).

[0272] The optical path switching and sleep control determination in step Sa303 is a determination of whether the fifth switching condition in step Sa104 is satisfied. Here, it is assumed that the fifth switching condition in step Sa104 is satisfied. If the fifth switching condition is satisfied, the real-time analysis unit 522 instructs the optical path switching control unit 531 to perform optical path switching control and instructs the sleep control unit 532 to perform sleep control.

[0273] The optical path switching control unit 531 notifies the switching device 43 and the concentrator 45 of the optical path switching destination information (step Sa304). The optical path switching destination information is information related to the switching destination of the optical path. In the example shown in Fig. 39, the optical path switching destination information includes information indicating the switching destination OLT 44-1 as the switching destination of the optical path. When the switching device 43 is notified of the optical path switching destination information from the management control device 50, it instructs the ONUs 42 connected to the switching source OLT 44-2, the switching destination OLT 44-1, and the switching source OLT 44-2 to switch the optical paths (step Sa305). For example, the switching device 43 instructs the ONU 42 connected to the source OLT 44-2 to switch the optical path to the destination OLT 44-1, instructs the destination OLT 44-1 to switch so that an optical path is connected to the ONU 42 connected to the source OLT 44-2, and instructs the source OLT 44-2 not to set an optical path.

[0274] The ONU 42 connected to the switching source OLT 44-2, the switching destination OLT 44-1, and the switching source OLT 44-2 prepare to switch the optical path (steps Sa306, Sa307, and Sa308). The ONU 42 connected to the switching source OLT 44-2, the switching destination OLT 44-1, and the switching source OLT 44-2 transmit an optical path switching response notification to the switching device 43 (steps Sa309, Sa310, and Sa311).

[0275] When the switching device 43 receives an optical path switching response notification from the ONU 42 connected to the source OLT 44-2, the destination OLT 44-1, and the source OLT 44-2, it sends an optical path switching start notification to the ONU 42 connected to the ONU 42 connected to the source OLT 44-2 and the destination OLT 44-1 (step Sa312).

[0276] The ONU 42 connected to the switching source OLT 44-2 and the switching destination OLT 44-1 switch their optical paths in response to receiving the optical path switching start notification (steps Sa313 and Sa314). This process switches the optical path of the ONU 42 connected to the switching source OLT 44-2 to the switching destination OLT 44-1. That is, the ONU 42 and the switching destination OLT 44-1 become capable of communicating with each other.

[0277] The switching destination OLT 44-1 transmits a path switching request to the core device 46 (step Sa315). The core device 46 switches the path in response to the path switching request (step Sa316). When the path switching is complete, the core device 46 transmits a path switching response notification to the switching destination OLT 44-1 (step Sa317).

[0278] When the optical path switching is completed, the ONU 42 transmits an optical path switching completion notification to the management and control device 50 (step Sa318). When the switching of the optical path is completed, the switching destination OLT 44-1 transmits an optical path switching completion notification to the management and control device 50 (step Sa319).

[0279] When the sleep control unit 532 of the management control device 50 receives an optical path switching completion notification from the destination of the optical path switching start notification, it transmits a sleep permission notification to the switching source OLT 44-2 (step Sa320). When the switching source OLT 44-2 receives the sleep permission notification from the management control device 50, it transmits a sleep response notification to the management control device 50 (step Sa321). After transmitting the sleep response notification, the switching source OLT 44-2 transitions to a sleep state (step Sa322).

[0280] 40 is a flowchart showing an example of the flow of a sleep release process executed by the management control device 50 in the fifth embodiment. The acquisition unit 511 acquires the number of accommodated terminals and information on sleeping OLTs 44-k as collaboration information from each OLT 44 (step Sa401). The acquisition unit 511 notifies the analysis unit 52 of the acquired information on the number of accommodated terminals and sleeping OLTs 44-k.

[0281] The real-time analysis unit 522 reads information on the maximum number of terminals that can be accommodated in each OLT 44 and information on the ONUs 42 that were connected to the sleeping OLT 44-k from the cooperation information storage unit 521 (step Sa402).The real-time analysis unit 522 calculates the number of terminals that can be additionally accommodated in each OLT 44 based on the cooperation information for each OLT 44 stored in the cooperation information storage unit 521 (step Sa403).

[0282] Next, the real-time analysis unit 522 assigns the value 1 to the constant i (step Sa404). ｉ <u ｉ It is determined whether or not the following is satisfied (step Sa405). ｉ <u ｉ The condition indicated by is a specific example of the first sleep release condition. ｉ <u ｉ ) is satisfied (step Sa405-YES), it is determined that the sleep state of the sleeping OLT 44-k needs to be released and the optical path needs to be switched.

[0283] The real-time analysis unit 522 notifies the control unit 53 of the determination result. The sleep control unit 532 sends an instruction to the sleeping OLT 44-k to cancel the sleep state based on the determination result (step Sa406). The optical path switching control unit 531 obtains information about the ONUs 42 that were connected to the OLT 44-k before the sleep state from the information obtained in the processing of step Sa402. The optical path switching control unit 531 instructs the ONUs 42 that were connected to the OLT 44-k before the sleep state to change their connection to the OLT 44-k.

[0284] In the process of step Sa405, the real-time analysis unit 522 determines whether the first sleep release condition (e.g., U ｉ <u ｉ If it is determined that the condition i is not satisfied (step Sa405—NO), the real-time analysis unit 522 determines whether i is the maximum value (step Sa408). If it is determined that i is the maximum value (step Sa408—YES), the real-time analysis unit 522 ends the process.

[0285] On the other hand, if the real-time analysis unit 522 determines that i is not the maximum value (step Sa408—NO), it adds 1 to the value of i (step Sa409). Thereafter, the real-time analysis unit 522 executes the process of step Sa405 again.

[0286] Here, the processing in Fig. 40 will be explained using specific numerical values. As an example, it is assumed that the total number of OLTs 44 is 2 (I = 2), the maximum number of terminals that OLT 44-1 can accommodate is 1000, the number of terminals that OLT 44-1 can accommodate is 800, the maximum number of terminals that OLT 44-2 can accommodate is 800, and the number of terminals that OLT 44-2 can accommodate is 1000.

[0287] If i=1, U １ <u １ The real-time analysis unit 522 determines whether the first sleep wakeup condition (for example, U ｉ <u ｉIf it is determined that the condition i is not satisfied (step Sa405—NO), it is determined whether i is the maximum value (step Sa408). Since i=1 at present, the real-time analysis unit 522 determines that i is not the maximum value.

[0288] The real-time analysis unit 522 adds 1 to the value of i to set it to i=2. The real-time analysis unit 522 executes the process of step Sa405 again. When i=2, U ２ <u ２ Since the first sleep cancellation condition is satisfied, the process proceeds to steps Sa406 and Sa407.

[0289] 41 is a sequence diagram showing an example of a detailed flow of a sleep release process executed by the wired network system 200 according to the fifth embodiment. In the explanation of FIG. 41, it is assumed that the OLT 44-2 is in a sleep state.

[0290] The OLT 44-2 is in a sleep state (step Sa501). The acquisition unit 511 of the management control device 50 acquires cooperation information from the OLT 44-1 at a predetermined interval or at any timing (step Sa502). The acquisition unit 511 stores the acquired cooperation information in the cooperation information storage unit 521. When the cooperation information is stored in the cooperation information storage unit 521, the real-time analysis unit 522 performs optical path switching and sleep control determination (step Sa503). The optical path switching and sleep control determination in step Sa503 is based on whether or not the sleep release condition is met. Here, it is assumed that the sleep release condition is met.

[0291] The sleep control unit 532 of the management control device 50 transmits a sleep release notification to the OLT 44-2 (step Sa504). In response to receiving the sleep release notification, the OLT 44-2 transmits a sleep release response notification to the management control device 50 (step Sa505).

[0292] The optical path switching control unit 531 notifies the optical path switching destination information to the switching device 43 and the concentrator 45 (step Sa506). When the switching device 43 is notified of the optical path switching destination information from the management control device 50, it instructs the ONU 42, OLT 44-1, and OLT 44-2 to switch the optical paths (step Sa507).

[0293] The ONU 42, the OLT 44-1, and the OLT 44-2 prepare to switch the optical path (steps Sa508, Sa509, and Sa510). When the ONU 42, the OLT 44-1, and the OLT 44-2 have completed the preparation for switching the optical path, they transmit an optical path switching response notification indicating that the preparation for switching has been completed to the switching device 43 (steps Sa511, Sa512, and Sa513).

[0294] When the switching device 43 receives the optical path switching response notifications from the ONU 42, the OLT 44-1, and the OLT 44-2, it transmits an optical path switching start notification to the ONU 42, the OLT 44-1, and the OLT 44-2 (step Sa514).

[0295] In response to receiving the optical path switching start notification, the ONU 42, OLT 44-1, and OLT 44-2 switch the optical paths (steps Sa515, Sa516, and Sa517). The OLT 44-1 transmits a path switching request to the concentrator 45 (step Sa518). The concentrator 45 switches the path in response to receiving the path switching request (step Sa519). When the path switching is complete, the concentrator 45 transmits a path switching response notification to the OLT 44-1 (step Sa520).

[0296] When the optical path switching is completed, the ONU 42 transmits an optical path switching completion notification to the management and control device 50 (step Sa521). When the optical path switching is completed, the OLT 44-1 transmits an optical path switching completion notification to the management and control device 50 (step Sa522). When the optical path switching is completed, the OLT 44-2 transmits an optical path switching completion notification to the management and control device 50 (step Sa523).

[0297] The wired network system 200 configured as described above includes one or more ONUs 42 that perform wired communication with one or more terminals 41, multiple OLTs 44 connected to the one or more ONUs 42 via a switching device 43, a collaboration information collector 51 that acquires collaboration information indicating the status of communication between the multiple OLTs 44 and the one or more terminals 41 at a predetermined interval or at any timing, an optical path switching controller 531 that controls the switching of the optical paths between the one or more ONUs 42 and the multiple OLTs 44 when it is determined based on the collaboration information that switching of the optical paths between the one or more ONUs 42 and the multiple OLTs 44 is necessary, and a sleep controller 532 that transitions the OLTs 44 that are capable of sleeping into a sleep state after the optical path switching is performed. This allows for the optical path switching and sleep control to be performed while analyzing the load of each OLT 44. This allows for increased power saving without degrading communication quality.

[0298] (Variation 1 of Fifth Embodiment) In the above-described embodiment, the configuration in which the management control device 50 directly acquires the collaboration information from the OLT 44 has been described. The management control device 50 may acquire the collaboration information via another device (e.g., a controller). FIG. 42 is a diagram showing a configuration example of a wired NW system 200a in Variation 1 of the fifth embodiment. The wired NW system 200a includes one or more ONUs 42, a switching device 43, multiple OLTs 44, a concentrator 45, a core device 46, a management control device 50, and a controller 60a. As shown in FIG. 42, in the wired NW system 200a, the controller 60a is provided between the management control device 50 and the OLT 44.

[0299] The controller 60a acquires cooperation information from each OLT 44 at a predetermined period or at any timing. The controller 60a transmits the acquired cooperation information to the management control device 50. The controller 60a may receive a sleep control instruction from the management control device 50 and transmit it to the switching source OLT. This configuration allows the management control device 50 to collect cooperation information via wireless communication.

[0300] (Variation 2 of Fifth Embodiment) In the above-described embodiment, a configuration has been shown in which the management control device 50 performs optical path switching control processing and sleep control processing. In contrast, a switching device 43 may be configured to perform optical path switching control processing and sleep control processing. Fig. 43 is a diagram showing a configuration example of a wired NW system 200b in Variation 2 of the fifth embodiment. The wired NW system 200b includes one or more ONUs 42, a switching device 43b, multiple OLTs 44, a concentrator 45, a core device 46, and a management control device 50b.

[0301] As shown in Fig. 43, the switching device 43b includes a control unit 53, while the management control device 50b does not include a control unit 53. The real-time analysis unit 522 of the management control device 50b notifies the switching device 43b of the analysis result. The real-time analysis unit 522 may notify the switching device 43b of the analysis result only when optical path switching and sleep control are performed. The control unit 53 of the switching device 43b performs optical path switching control processing and sleep control processing based on the analysis result notified from the management control device 50b.

[0302] Fig. 44 is a sequence diagram showing an example of a detailed flow of sleep processing executed by the wired NW system 200b in Modification 2 of the fifth embodiment. In Fig. 44, the same processes as those in Fig. 39 are assigned the same reference numerals as those in Fig. 39, and the description thereof will be omitted. In the description of Fig. 44, it is assumed that the OLT 44-1 is the switching destination OLT and the OLT 44-2 is the switching source OLT. Here, the description will be given by referring to the switching destination OLT 44-1 and the switching source OLT 44-2.

[0303] After the processes from step Sa301 to step Sa303 are executed, if the fifth switching condition is satisfied, the real-time analysis unit 522 instructs the switching device 43b to perform optical path switching control and sleep control (step Sa601). The switching device 43b receives the instructions transmitted from the management control device 50b.

[0304] The optical path switching control unit 531 of the switching device 43b determines the optical path switching destination from the information included in the received instruction (step Sa602). The optical path switching control unit 531 notifies the concentrator 45 of the optical path switching destination information (step Sa603). Thereafter, the optical path switching control unit 531 instructs the ONU 42 connected to the switching source OLT 44-2, the switching destination OLT 44-1, and the switching source OLT 44-2 to switch the optical path (step Sa604). Thereafter, the processes from step Sa306 to step Sa317 are executed.

[0305] When the optical path switching is completed, the ONU 42 transmits an optical path switching completion notification to the switching device 43b (step Sa605). The ONU 42 may also transmit the optical path switching completion notification to the management and control device 50b. When the switching destination OLT 44-1 completes the optical path switching, it transmits an optical path switching completion notification to the switching device 43b (step Sa606). The ONU 42 may also transmit the optical path switching completion notification to the management and control device 50b.

[0306] When the sleep control unit 532 provided in the switching device 43b receives an optical path switching completion notification from the destination of the optical path switching start notification, it transmits a sleep permission notification to the switching source OLT 44-2 (step Sa607). When the switching source OLT 44-2 receives the sleep permission notification from the switching device 43b, it transmits a sleep response notification to the switching device 43b (step Sa608). After transmitting the sleep response notification, the switching source OLT 44-2 transitions to a sleep state (step Sa322).

[0307] Fig. 45 is a sequence diagram showing an example of a detailed flow of a sleep release process executed by the wired network system 200b in Modification 2 of the fifth embodiment. In Fig. 45, the same processes as those in Fig. 41 are denoted by the same reference numerals as those in Fig. 41, and the description thereof will be omitted. In the description of Fig. 45, it is assumed that the OLT 44-2 is in a sleep state.

[0308] After the processes from step Sa501 to step Sa503 are executed, if the sleep release condition is satisfied, the real-time analyzer 522 instructs the switching device 43b to perform optical path switching control and sleep control (step Sa701). The switching device 43b receives the instructions transmitted from the management control device 50b.

[0309] The sleep control unit 532 of the switching device 43b transmits a sleep release notification to the OLT 44-2 based on the information included in the received instruction (step Sa702). In response to receiving the sleep release notification, the OLT 44-2 transmits a sleep release response notification to the switching device 43b (step Sa703).

[0310] The optical path switching control unit 531 of the switching device 43b determines the switching destination of the optical path from the information included in the received instruction (step Sa704). The optical path switching control unit 531 of the switching device 43b notifies the concentrator 45 of the optical path switching destination information (step Sa705). Thereafter, the processes from step Sa507 to step Sa520 are executed.

[0311] When the optical path switching is completed, the ONU 42 transmits an optical path switching completion notification to the switching device 43b (step Sa706). When the optical path switching is completed, the OLT 44-1 transmits an optical path switching completion notification to the switching device 43b (step Sa707). When the optical path switching is completed, the OLT 44-2 transmits an optical path switching completion notification to the switching device 43b (step Sa708).

[0312] Sixth Embodiment The sixth embodiment differs from the fifth embodiment in that the cooperation information further includes processing load information (for example, information on memory usage rate for each OLT 44 or information on CPU usage rate). In the sixth embodiment, the information on memory usage rate for each OLT 44 will be described as an example of the processing load information.

[0313] 46 is a diagram illustrating a configuration example of a wired network system 200c according to the sixth embodiment. The wired network system 200c according to the sixth embodiment includes one or more ONUs 42, a switching device 43, multiple OLTs 44, a concentrator 45, a core device 46, and a management control device 50c. The management control device 50c includes a collaboration information collector 51c, an analyzer 52c, and a controller 53.

[0314] The collaboration information collection unit 51c includes an acquisition unit 511 and a monitoring unit 512c. The monitoring unit 512c monitors each OLT 44 and measures the memory usage rate for each OLT 44. The monitoring unit 512c outputs information on the memory usage rate measured for each OLT 44 to the analysis unit 52c as collaboration information.

[0315] The analysis unit 52c includes an association information storage unit 521 and a real-time analysis unit 522c. Based on the association information, the real-time analysis unit 522c analyzes the communication status in the wired network system 200c, such as the amount of change in the number of connections of the OLT 44 per unit time. Specifically, the real-time analysis unit 522c divides the memory usage rate by the number of currently accommodated terminals to estimate the memory usage rate per unit. Furthermore, the real-time analysis unit 522c multiplies the number of accommodated terminals in other OLTs 44 by the memory usage rate per unit of the target OLT 44, and determines to switch the optical path and go to sleep if the memory usage rate does not exceed 100% and the number of accommodated terminals in the OLT 44 is less than the number of terminals that the target OLT 44 can additionally accommodate.

[0316] Fig. 47 is a flowchart showing an example of the flow of sleep processing executed by the management control device 50c in the sixth embodiment. In Fig. 47, the same processes as those in Fig. 37 are denoted by the same reference numerals as in Fig. 37, and the description thereof will be omitted.

[0317] The collaboration information collection unit 51c acquires collaboration information from each OLT 44 (step Sa801). Specifically, the acquisition unit 511 acquires, as collaboration information, information on at least the number of accommodated terminals and information on the maximum number of accommodated terminals from each OLT 44. Furthermore, the monitoring unit 512c measures the memory usage rate for each OLT 44. The collaboration information collection unit 51c accumulates the acquired collaboration information for each OLT 44 in the collaboration information storage unit 521 (step Sa802). Specifically, the collaboration information collection unit 51c accumulates, as collaboration information, information on the memory usage rate for each OLT 44 in the collaboration information storage unit 521, in addition to collaboration information including, from each OLT 44, information on at least the number of accommodated terminals and information on the maximum number of accommodated terminals.

[0318] The real-time analysis unit 522c calculates the number of additional terminals that can be accommodated by each OLT 44 based on the linkage information for each OLT 44 stored in the linkage information storage unit 521 (step Sa803). Furthermore, the real-time analysis unit 522c estimates the memory usage rate of each OLT 44 based on the linkage information for each OLT 44 stored in the linkage information storage unit 521 (step Sa804).

[0319] The real-time analysis unit 522c determines whether a sixth switching condition is satisfied (step Sa805). The sixth switching condition indicates that switching of the optical path between the ONU 42 and the OLT 44 is necessary, and for example, the number of terminals that can be added to a certain OLT 44 is greater than the number of terminals that can be accommodated in the OLT 44 that is the target of sleep determination, and the memory usage rate does not exceed 100%.

[0320] If the real-time analysis unit 522c determines that the sixth switching condition is satisfied (step Sa805—YES), the process from step Sa105 onward is executed. On the other hand, if the real-time analysis unit 522c determines that the sixth switching condition is not satisfied (step Sa805—NO), the process from step Sa107 onward is executed.

[0321] Fig. 48 is a flowchart showing an example of the flow of sleep processing executed by the management control device 50c in the sixth embodiment. Note that the processing shown in Fig. 48 will be described by showing more specific details of the processing shown in Fig. 47. In Fig. 48, processing that is the same as that in Fig. 38 is assigned the same reference numerals as in Fig. 38, and description thereof will be omitted.

[0322] The acquisition unit 511 acquires, as cooperation information, the maximum number of terminals that can be accommodated in each OLT 44, connected ONU information, and information on the number of terminals that can be accommodated in each OLT 44 from each OLT 44. Furthermore, the monitoring unit 512c acquires information on the memory usage rate of each OLT 44 (step Sa901).

[0323] The acquisition unit 511 accumulates the acquired association information for each OLT 44 in the association information accumulation unit 521. The monitoring unit 512c accumulates the acquired information on the memory usage rate of each OLT 44 as association information (step Sa902). The real-time analysis unit 522c calculates the number of additional terminals that can be accommodated by each OLT 44 based on the association information for each OLT 44 accumulated in the association information accumulation unit 521 (step Sa903). Furthermore, the real-time analysis unit 522c estimates the memory usage rate per OLT 44 based on the association information for each OLT 44 accumulated in the association information accumulation unit 521 (step Sa904).

[0324] Next, the real-time analysis unit 522c assigns the value 1 to the constant i (step Sa905). Next, the real-time analysis unit 522c assigns the value (i+1) to k (step Sa906). After that, the real-time analysis unit 522c calculates 100-M ｉ >m ｉ ×u ｋ , and U ｉ -u ｉ >u ｋ In the sixth to eighth embodiments, it is determined whether M ｉ represents the memory usage rate of the OLT 44-i, and m ｉ represents the memory usage rate per OLT 44. ｉ is calculated in the process of step Sa904. ｉ >m ｉ ×uｋ , and U ｉ -u ｉ >u ｋ The condition indicated by is a specific example of the sixth switching condition.

[0325] If the real-time analysis unit 522c determines that the sixth switching condition is satisfied (YES in step Sa907), it executes the processes from step Sa207 onward. On the other hand, if the real-time analysis unit 522c determines that the sixth switching condition is not satisfied (NO in step Sa907), it executes the processes from step Sa209 onward.

[0326] Here, the processing of Figure 48 will be explained using specific numerical values. As an example, assume that the maximum number of accommodating terminals in OLT 44-1 is 1000, the number of accommodating terminals in OLT 44-1 is 100, the memory utilization rate M1 of OLT 44-1 is 20%, the maximum number of accommodating terminals in OLT 44-2 is 800, the number of accommodating terminals in OLT 44-2 is 200, and the memory utilization rate M2 of OLT 44-2 is 30%. In this case, in the processing of step Sa904, the real-time analysis unit 522c calculates m1 = 20 / 100 = 0.2 and m2 = 30 / 200 = 0.15 as approximate values ​​of the memory utilization rate per OLT 44. m1 represents the approximate value of the memory utilization rate per OLT 44-1, and m2 represents the approximate value of the memory utilization rate per OLT 44-2.

[0327] In the process of step Sa907, the real-time analysis unit 522c ｉ >m ｉ ×u ｋ , and U ｉ -u ｉ >u ｋ When i=1 and k=2, it is expressed as follows: 100-M ｉ ⇒100-20=80 ・m ｉ ×u ｋ ⇒0.2×200=40 ・U ｉ -u ｉ ⇒1000-100=900

[0328] Based on the above results, 100-M ｉ >m ｉ×u ｋ , and U ｉ -u ｉ >u ｋ are 180 > 40 and 900 > 200. In this case, the real-time analysis unit 522c determines that the sixth switching condition is satisfied. Therefore, the real-time analysis unit 522c makes a switching decision to connect the ONU 42 connected to the OLT 44-2 to the OLT 44-1, and makes a sleep decision to transition the OLT 44-2 to a sleep state. The real-time analysis unit 522c notifies the optical path switching control unit 531 of the result of the switching decision to connect the ONU 42 connected to the OLT 44-2 to the OLT 44-1, and notifies the sleep control unit 532 of the result of the sleep decision to transition the OLT 44-2 to a sleep state.

[0329] As a result, the optical path switching control unit 531 controls the switching of the optical path so that the ONU 42 connected to the OLT 44-2 is connected to the OLT 44-1 in accordance with the notification from the real-time analysis unit 522c. The sleep control unit 532 controls the sleep so that the OLT 44-2 transitions to a sleep state in accordance with the notification from the real-time analysis unit 522c.

[0330] Figure 49 is a sequence diagram showing an example of a detailed flow of sleep processing executed by the wired network system 200c in the sixth embodiment. In Figure 49, the same processes as those in Figure 39 are assigned the same reference numerals as those in Figure 39, and their description will be omitted. In the description of Figure 49, it is assumed that the OLT 44-1 is the switching destination OLT and the OLT 44-2 is the switching source OLT. Here, the description will be given by referring to the switching destination OLT 44-1 and the switching source OLT 44-2.

[0331] The cooperation information collection unit 51c of the management control device 50c acquires cooperation information from the switching destination OLT 44-1 and the switching source OLT 44-2 at a predetermined period or at any timing (step Sa1001, step Sa1002). Note that the cooperation information acquired in step Sa1001 and step Sa1002 includes at least information on the number of accommodated terminals, information on the maximum number of accommodated terminals, etc., as well as information on the memory usage rate for each OLT 44. The cooperation information collection unit 51c stores the acquired cooperation information in the cooperation information storage unit 521.

[0332] When the coordination information is accumulated in the coordination information accumulation unit 521, the real-time analysis unit 522c performs optical path switching and sleep control determination (step Sa1003). The optical path switching and sleep control determination in step Sa1003 is a determination of whether the sixth switching condition in step Sa805 is satisfied. Here, it is assumed that the sixth switching condition in step Sa805 is satisfied. If the sixth switching condition is satisfied, the real-time analysis unit 522c executes the processing from step Sa304 onwards.

[0333] Fig. 50 is a flowchart showing an example of the flow of a sleep wake-up process executed by the management control device 50c in the sixth embodiment. In Fig. 50, the same processes as those in Fig. 40 are denoted by the same reference numerals as in Fig. 40, and the description thereof will be omitted.

[0334] The acquisition unit 511 acquires, as collaboration information, the number of accommodated terminals and information on sleeping OLTs 44-k from each OLT 44. Furthermore, the monitoring unit 512c acquires, as collaboration information, information on memory usage rates for each OLT 44 (step Sa1101). The acquisition unit 511 notifies the analysis unit 52c of the acquired number of accommodated terminals, information on sleeping OLTs 44-k, and information on memory usage rates.

[0335] The real-time analysis unit 522c of the analysis unit 52c reads information on the maximum number of terminals that can be accommodated in each OLT 44 and information on the ONUs 42 that were connected to the sleeping OLT 44-k from the cooperation information accumulation unit 521 (step Sa1102).The real-time analysis unit 522c calculates the number of terminals that can be additionally accommodated in each OLT 44 based on the obtained cooperation information for each OLT 44 (step Sa1103).

[0336] Next, the real-time analysis unit 522c assigns the value 1 to the constant i (step Sa1104). ｉ <u ｉ , or T １ <M ｉ It is determined whether any of the following conditions is satisfied (step Sa1105). ｉ <u ｉ , or T １ <M ｉ The condition shown in is a specific example of the second sleep wake-up condition. １ <M ｉ is the memory usage rate M of the OLT 44-i. ｉ is the threshold T １ (for example, a predetermined value such as 80, 90, or 100%).

[0337] The real-time analysis unit 522c determines whether a second sleep wakeup condition (e.g., U ｉ <u ｉ , or T １ <M ｉ ) is satisfied (step Sa1105-YES), it is determined that the optical path needs to be switched and the sleeping OLT 44-k needs to be woken up.

[0338] The real-time analysis unit 522c notifies the control unit 53 of the determination result. Then, the processing from step Sa406 onward is executed. Meanwhile, the real-time analysis unit 522c determines whether the second sleep cancellation condition (for example, U ｉ <u ｉ , or T １ <M ｉ If it is determined that the above condition is not satisfied (step Sa1105--NO), the process of step Sa408 is executed.

[0339] Fig. 51 is a sequence diagram showing an example of a detailed flow of a sleep release process executed by the wired network system 200c in the sixth embodiment. In Fig. 51, the same processes as those in Fig. 41 are denoted by the same reference numerals as those in Fig. 41, and the description thereof will be omitted. In the description of Fig. 51, it is assumed that the OLT 44-2 is in a sleep state.

[0340] The OLT 44-2 is in a sleep state (step Sa501). The cooperation information collection unit 51c of the management control device 50c acquires cooperation information from the OLT 44-1 at a predetermined period or at any timing (step Sa1201). Note that the cooperation information acquired in step Sa1201 includes at least information on the number of accommodated terminals, information on the maximum number of accommodated terminals, etc., as well as information on the memory usage rate for each OLT 44. The cooperation information collection unit 51c stores the acquired cooperation information in the cooperation information storage unit 521.

[0341] When the cooperation information is accumulated in the cooperation information accumulation unit 521, the real-time analysis unit 522c performs optical path switching and sleep control determination (step Sa1202). The optical path switching and sleep control determination in step Sa1202 is based on whether the sleep cancellation condition is satisfied. Here, it is assumed that the sleep cancellation condition is satisfied. If the sleep cancellation condition is satisfied, the real-time analysis unit 522c executes the processing from step Sa504 onwards.

[0342] The wired network system 200c of the sixth embodiment configured as described above can achieve the same effects as those of the fifth embodiment. Specifically, in the wired network system 200c, the management control device 50c further acquires information on the memory usage rate of each OLT 44 as cooperation information and determines whether or not an optical path switching is necessary based on the cooperation information. When it is determined that an optical path switching is necessary, the management control device 50c controls the switching of the optical paths between one or more ONUs 42 and multiple OLTs 44. Furthermore, after the optical path switching is performed, the management control device 50c transitions the OLTs 44 that are capable of sleeping into a sleep state. This allows the management control device 50c to control the switching of the optical paths and the sleep state while analyzing the load of each OLT 44. This makes it possible to increase the power saving effect without degrading communication quality.

[0343] (Variation 1 of the Sixth Embodiment) In the above-described embodiment, the management control device 50c directly acquires the cooperation information from the OLT 44. The management control device 50c may acquire the cooperation information via another device (for example, a controller). The wired NW system 200c newly includes a controller 60a, and the controller 60a is provided between the management control device 50c and the OLT 44.

[0344] The controller 60a acquires cooperation information from each OLT 44 at a predetermined period or at any timing. The controller 60a transmits the acquired cooperation information to the management control device 50c. The controller 60a may receive a sleep control instruction from the management control device 50c and transmit it to the switching source OLT. This configuration allows the management control device 50c to collect cooperation information via wireless communication.

[0345] (Variation 2 of Sixth Embodiment) In the above-described embodiment, the configuration has been shown in which the management control device 50c performs optical path switching control processing and sleep control processing. In contrast, the switching device 43 may be configured to perform optical path switching control processing and sleep control processing. In such a configuration, the switching device 43 includes a control unit 53, and the management control device 50c does not include a control unit 53. The real-time analysis unit 522c of the management control device 50c notifies the switching device 43 of the analysis result. Note that the real-time analysis unit 522c may notify the switching device 43 of the analysis result only when optical path switching and sleep control are performed. The control unit 53 of the switching device 43 performs optical path switching control processing and sleep control processing based on the analysis result notified from the management control device 50c.

[0346] Fig. 52 is a sequence diagram showing an example of a detailed flow of sleep processing executed by the wired NW system 200c in Modification 2 of the sixth embodiment. In Fig. 52, the same processes as those in Fig. 49 are denoted by the same reference numerals as those in Fig. 49, and the description thereof will be omitted.

[0347] After the processes from step Sa1001 to step Sa1003 are executed, if the sixth switching condition is satisfied, the real-time analysis unit 522c instructs the switching device 43b to perform optical path switching control and sleep control (step Sa1301). The switching device 43b receives the instructions transmitted from the management control device 50c.

[0348] The optical path switching control unit 531 of the switching device 43b determines the switching destination of the optical path from the information included in the received instruction (step Sa1302). The optical path switching control unit 531 notifies the concentrator 45 of the optical path switching destination information (step Sa1303). Thereafter, the optical path switching control unit 531 instructs the ONU 42 connected to the switching source OLT 44-2, the switching destination OLT 44-1, and the switching source OLT 44-2 to switch the optical path (step Sa1304). Thereafter, the processes from step Sa306 to step Sa317 are executed.

[0349] When the optical path switching is completed, the ONU 42 transmits an optical path switching completion notification to the switching device 43b (step Sa1305). The ONU 42 may also transmit the optical path switching completion notification to the management and control device 50c. When the optical path switching is completed, the switching destination OLT 44-1 transmits an optical path switching completion notification to the switching device 43 (step Sa1306). The ONU 42 may also transmit the optical path switching completion notification to the management and control device 50c.

[0350] When the sleep control unit 532 provided in the switching device 43b receives an optical path switching completion notification from the destination of the optical path switching start notification, it transmits a sleep permission notification to the switching source OLT 44-2 (step Sa1307). When the switching source OLT 44-2 receives the sleep permission notification from the switching device 43, it transmits a sleep response notification to the switching device 43b (step Sa1308). After transmitting the sleep response notification, the switching source OLT 44-2 transitions to a sleep state (step Sa322).

[0351] Fig. 53 is a sequence diagram showing an example of a detailed flow of a sleep release process executed by the wired network system 200c in Modification 2 of the sixth embodiment. In Fig. 53, the same processes as those in Fig. 51 are assigned the same reference numerals as those in Fig. 51, and the description thereof will be omitted. In the description of Fig. 51, it is assumed that the OLT 44-2 is in a sleep state.

[0352] After the processes of steps Sa501, Sa1201, and Sa1202 are performed, if the sleep release condition is satisfied, the real-time analysis unit 522c instructs the switching device 43b to perform optical path switching control and sleep control (step Sa1401). The switching device 43b receives the instructions transmitted from the management control device 50c.

[0353] The sleep control unit 532 of the switching device 43b transmits a sleep release notification to the OLT 44-2 based on the information included in the received instruction (step Sa1402). In response to receiving the sleep release notification, the OLT 44-2 transmits a sleep release response notification to the switching device 43b (step Sa1403).

[0354] The optical path switching control unit 531 of the switching device 43b determines the switching destination of the optical path from the information included in the received instruction (step Sa1404). The optical path switching control unit 531 of the switching device 43b notifies the concentrator 45 of the optical path switching destination information (step Sa1405). Thereafter, the processes from step Sa507 to step Sa520 are executed.

[0355] When the optical path switching is completed, the ONU 42 transmits an optical path switching completion notification to the switching device 43b (step Sa1406). When the optical path switching is completed, the OLT 44-1 transmits an optical path switching completion notification to the switching device 43b (step Sa1407). When the optical path switching is completed, the OLT 44-2 transmits an optical path switching completion notification to the switching device 43b (step Sa1408).

[0356] (Seventh embodiment) The seventh embodiment differs from the sixth embodiment in that the coordination information further includes processing load information (for example, information on memory usage rate for each OLT 44 or information on CPU usage rate) and processing delay information for each OLT 44. The system configuration is the same as that of the sixth embodiment. In the seventh embodiment, information on memory usage rate for each OLT 44 will be described as an example of processing load information.

[0357] The management control device 50c determines optical path switching and sleep based on information on the number of terminals for each OLT 44, information on memory usage for each OLT 44, and processing delay information for each OLT 44. For example, the monitoring unit 512c monitors each OLT 44 and measures the memory usage for each OLT 44. Furthermore, the monitoring unit 512c monitors each OLT 44 and collects processing delay information for each OLT 44. The monitoring unit 512c outputs the information on memory usage measured for each OLT 44 and the processing delay information for each OLT 44 to the analysis unit 52c as linkage information.

[0358] Fig. 54 is a flowchart showing an example of the flow of sleep processing executed by the management control device 50c in the seventh embodiment. In Fig. 54, the same processes as those in Fig. 47 are denoted by the same reference numerals as in Fig. 47, and the description thereof will be omitted.

[0359] The collaboration information collection unit 51c acquires collaboration information from each OLT 44 (step Sa1501). Specifically, the acquisition unit 511 acquires, as collaboration information, information on at least the number of accommodated terminals and information on the maximum number of accommodated terminals from each OLT 44. Furthermore, the monitoring unit 512c measures the memory usage rate for each OLT 44 and acquires processing delay information for each OLT 44. The collaboration information collection unit 51c accumulates the acquired collaboration information for each OLT 44 in the collaboration information storage unit 521 (step Sa1502). Specifically, the collaboration information collection unit 51c accumulates, as collaboration information, information on the memory usage rate for each OLT 44 and the processing delay information for each OLT 44 in the collaboration information storage unit 521, in addition to collaboration information including, from each OLT 44, information on at least the number of accommodated terminals and information on the maximum number of accommodated terminals.

[0360] The real-time analysis unit 522c calculates the number of additional terminals that can be accommodated by each OLT 44 based on the cooperation information for each OLT 44 stored in the cooperation information storage unit 521 (step Sa1503). Furthermore, the real-time analysis unit 522c estimates the memory usage rate of each OLT 44 based on the cooperation information for each OLT 44 stored in the cooperation information storage unit 521 (step Sa1504).

[0361] The real-time analysis unit 522c determines whether a seventh switching condition is satisfied (step Sa1505). The seventh switching condition is a condition indicating that switching of the optical path between the ONU 42 and the OLT 44 is necessary, and is, for example, that the number of terminals that can be added to a certain OLT 44 is greater than the number of terminals that can be accommodated in the OLT 44 that is the target of sleep determination, that the memory usage rate does not exceed 100%, and that the processing delay of the OLT 44 that is the target of sleep determination does not exceed a threshold.

[0362] If the real-time analysis unit 522c determines that the seventh switching condition is satisfied (step Sa1505—YES), the process from step Sa105 onward is executed. On the other hand, if the real-time analysis unit 522c determines that the seventh switching condition is not satisfied (step Sa1505—NO), the process from step Sa107 onward is executed.

[0363] Fig. 55 is a flowchart showing an example of the flow of sleep processing executed by the management control device 50c in the seventh embodiment. Note that the processing shown in Fig. 55 will be described by more specifically showing the processing shown in Fig. 54. In Fig. 55, processing that is the same as that in Fig. 48 is assigned the same reference numerals as in Fig. 48, and description thereof will be omitted.

[0364] The acquisition unit 511 acquires, as cooperation information, the maximum number of terminals accommodated in each OLT 44, connected ONU information, and information on the number of terminals accommodated in each OLT 44 from each OLT 44. Furthermore, the monitoring unit 512c acquires information on the memory usage rate and processing delay information of each OLT 44 (step Sa1601).

[0365] The acquisition unit 511 accumulates the acquired association information for each OLT 44 in the association information accumulation unit 521. Furthermore, the monitoring unit 512c accumulates the acquired memory usage rate information and processing delay information for each OLT 44 as association information (step Sa1602). The real-time analysis unit 522c calculates the number of additional terminals that can be accommodated by each OLT 44 based on the association information for each OLT 44 accumulated in the association information accumulation unit 521 (step Sa1603). Furthermore, the real-time analysis unit 522c estimates the memory usage rate per OLT 44 based on the association information for each OLT 44 accumulated in the association information accumulation unit 521 (step Sa1604).

[0366] Next, the real-time analysis unit 522c assigns the value 1 to the constant i (step Sa1605). Next, the real-time analysis unit 522c assigns the value (i+1) to k (step Sa1606). After that, the real-time analysis unit 522c calculates 100-M ｉ >m ｉ ×u ｋ , and U ｉ -u ｉ >u ｋ , and T>t ｉ It is determined whether or not T satisfies the threshold value (step Sa1607). ｉ represents the processing delay of the OLT 44-i. ｉ >m ｉ ×u ｋ , and U ｉ -u ｉ>u ｋ , and T>t ｉ The condition indicated by is a specific example of the seventh switching condition.

[0367] If the real-time analysis unit 522c determines that the seventh switching condition is satisfied (step Sa1607—YES), it executes the processes from step Sa207 onward. On the other hand, if the real-time analysis unit 522c determines that the seventh switching condition is not satisfied (step Sa1607—NO), it executes the processes from step Sa209 onward.

[0368] Figure 56 is a sequence diagram showing an example of a detailed flow of sleep processing executed by the wired network system 200c in the seventh embodiment. In Figure 56, the same processes as those in Figure 49 are assigned the same reference numerals as those in Figure 49, and their description will be omitted. In the description of Figure 56, it is assumed that the OLT 44-1 is the switching destination OLT and the OLT 44-2 is the switching source OLT. Here, the description will be given by referring to the switching destination OLT 44-1 and the switching source OLT 44-2.

[0369] The cooperation information collection unit 51c of the management control device 50c acquires cooperation information from the switching destination OLT 44-1 and the switching source OLT 44-2 at a predetermined period or at any timing (steps Sa1701 and Sa1702). Note that the cooperation information acquired in steps Sa1701 and Sa1702 includes at least information on the number of accommodated terminals, information on the maximum number of accommodated terminals, etc., as well as information on the memory usage rate for each OLT 44 and processing delay information for each OLT 44. The cooperation information collection unit 51c stores the acquired cooperation information in the cooperation information storage unit 521.

[0370] When the cooperation information is accumulated in the cooperation information accumulation unit 521, the real-time analysis unit 522c performs optical path switching and sleep control determination (step Sa1703). The optical path switching and sleep control determination in step Sa1703 is a determination of whether the seventh switching condition in step Sa1505 is satisfied. Here, it is assumed that the seventh switching condition in step Sa1505 is satisfied. If the fifth switching condition is satisfied, the real-time analysis unit 522c executes the processing from step Sa304 onwards.

[0371] Fig. 57 is a flowchart showing an example of the flow of a sleep release process executed by the management control device 50c in the seventh embodiment. In Fig. 57, the same processes as those in Fig. 50 are denoted by the same reference numerals as in Fig. 50, and the description thereof will be omitted.

[0372] The acquisition unit 511 acquires, as collaboration information, the number of accommodated terminals and information on sleeping OLTs 44-k from each OLT 44. Furthermore, the monitoring unit 512c acquires, as collaboration information, information on memory usage rates for each OLT 44 and processing delay information for each OLT 44 (step Sa1751). The acquisition unit 511 notifies the analysis unit 52c of the acquired number of accommodated terminals, information on sleeping OLTs 44-k, information on memory usage rates, and processing delay information for each OLT 44.

[0373] The real-time analysis unit 522c of the analysis unit 52c reads information on the maximum number of terminals that can be accommodated in each OLT 44 and information on the ONUs 42 that were connected to the sleeping OLT 44-k from the association information accumulation unit 521 (step Sa1752).The real-time analysis unit 522c calculates the number of terminals that can be additionally accommodated in each OLT 44 based on the acquired association information for each OLT 44 (step Sa1753).

[0374] Next, the real-time analysis unit 522c assigns the value 1 to the constant i (step Sa1754). ｉ <u ｉ , or T １ <M ｉ , or T<t ｉ It is determined whether any one of the following conditions is satisfied (step Sa1755). ｉ <u ｉ , or T １ <M ｉ , or T<t ｉ The condition shown in is a specific example of the third sleep wake-up condition. ｉ means that the processing delay of the OLT 44-i exceeds the threshold.

[0375] The real-time analysis unit 522c determines whether a third sleep cancellation condition (e.g., U ｉ <u ｉ , or T １ <Mｉ , or T<t ｉ ) is satisfied (step Sa1755-YES), it is determined that the optical path needs to be switched and the sleeping OLT 44-k needs to be woken up.

[0376] The real-time analysis unit 522c notifies the control unit 53 of the determination result. Then, the processing from step Sa406 onward is executed. Meanwhile, the real-time analysis unit 522c determines whether the third sleep cancellation condition (for example, U ｉ <u ｉ , or T １ <M ｉ , or T<t ｉ ) is not satisfied (step Sa1755--NO), the process of step Sa408 is executed.

[0377] Fig. 58 is a sequence diagram showing an example of a detailed flow of a sleep release process executed by the wired network system 200c in the seventh embodiment. In Fig. 58, the same processes as those in Fig. 51 are assigned the same reference numerals as those in Fig. 51, and the description thereof will be omitted. In the description of Fig. 51, it is assumed that the OLT 44-2 is in a sleep state.

[0378] The OLT 44-2 is in a sleep state (step Sa501). The cooperation information collection unit 51c of the management control device 50c acquires cooperation information from the OLT 44-1 at a predetermined period or at any timing (step Sa1801). It is assumed that the cooperation information acquired in step Sa1801 includes information on memory usage rates and processing delay information for each OLT 44. The cooperation information collection unit 51c stores the acquired cooperation information in the cooperation information storage unit 521.

[0379] When the cooperation information is accumulated in the cooperation information accumulation unit 521, the real-time analysis unit 522c performs optical path switching and sleep control determination (step Sa1802). The optical path switching and sleep control determination in step Sa1802 is based on whether the sleep cancellation condition is satisfied. Here, it is assumed that the sleep cancellation condition is satisfied. If the sleep cancellation condition is satisfied, the real-time analysis unit 522c executes the processing from step Sa504 onwards.

[0380] The wired network system 200c of the seventh embodiment configured as described above can achieve the same effects as those of the fifth embodiment. Specifically, in the wired network system 200c of the seventh embodiment, the management control device 50c further acquires, as cooperation information, information on memory usage rates for each OLT 44 and processing delay information for each OLT 44, and determines whether or not optical path switching is necessary based on the cooperation information. When it is determined that optical path switching is necessary, the management control device 50c controls optical path switching between one or more ONUs 42 and multiple OLTs 44. Furthermore, after the optical path switching is performed, the management control device 50c transitions OLTs 44 that are capable of sleeping into a sleep state. This allows for control of optical path switching and sleep while analyzing the load of each OLT 44. This makes it possible to increase the power saving effect without degrading communication quality.

[0381] (Variation 1 of the Seventh Embodiment) In the above-described embodiment, the configuration has been described in which the management control device 50c directly acquires the cooperation information from the OLT 44. The management control device 50c may acquire the cooperation information via another device (for example, a controller). In such a configuration, the wired NW system 200c newly includes a controller 60a, and the controller 60a is provided between the management control device 50c and the OLT 44.

[0382] The controller 60a acquires cooperation information from each OLT 44 at a predetermined period or at any timing. The controller 60a transmits the acquired cooperation information to the management control device 50c. The controller 60a may receive a sleep control instruction from the management control device 50c and transmit it to the switching source OLT. This configuration allows the management control device 50c to collect cooperation information via wireless communication.

[0383] (Variation 2 of Seventh Embodiment) In the above-described embodiment, the configuration has been shown in which the management control device 50c performs optical path switching control processing and sleep control processing. In contrast, the switching device 43 may be configured to perform optical path switching control processing and sleep control processing. In such a configuration, the switching device 43 includes a control unit 53, and the management control device 50c does not include a control unit 53. The real-time analysis unit 522c of the management control device 50c notifies the switching device 43 of the analysis result. Note that the real-time analysis unit 522c may notify the switching device 43 of the analysis result only when optical path switching and sleep control are performed. The control unit 53 of the switching device 43 performs optical path switching control processing and sleep control processing based on the analysis result notified from the management control device 50c.

[0384] Fig. 59 is a sequence diagram showing an example of a detailed flow of sleep processing executed by the wired NW system 200c in Modification 2 of the seventh embodiment. In Fig. 59, the same processes as those in Fig. 56 are denoted by the same reference numerals as those in Fig. 56, and the description thereof will be omitted.

[0385] After the processes from step Sa1701 to step Sa1703 are executed, if the seventh switching condition is satisfied, the real-time analysis unit 522c instructs the switching device 43b to perform optical path switching control and sleep control (step Sa1901). The switching device 43b receives the instructions transmitted from the management control device 50c.

[0386] The optical path switching control unit 531 of the switching device 43b determines the switching destination of the optical path from the information included in the received instruction (step Sa1902). The optical path switching control unit 531 notifies the concentrator 45 of the optical path switching destination information (step Sa1903). Thereafter, the optical path switching control unit 531 instructs the ONU 42 connected to the switching source OLT 44-2, the switching destination OLT 44-1, and the switching source OLT 44-2 to switch the optical path (step Sa1904). Thereafter, the processes from step Sa306 to step Sa317 are executed.

[0387] When the optical path switching is completed, the ONU 42 transmits an optical path switching completion notification to the switching device 43b (step Sa1905). The ONU 42 may also transmit the optical path switching completion notification to the management and control device 50c. When the optical path switching is completed, the switching destination OLT 44-1 transmits an optical path switching completion notification to the switching device 43 (step Sa1906). The ONU 42 may also transmit the optical path switching completion notification to the management and control device 50c.

[0388] When the sleep control unit 532 included in the switching device 43b receives an optical path switching completion notification from the destination of the optical path switching start notification, it transmits a sleep permission notification to the switching source OLT 44-2 (step Sa1907). When the switching source OLT 44-2 receives the sleep permission notification from the switching device 43, it transmits a sleep response notification to the switching device 43b (step Sa1908). After transmitting the sleep response notification, the switching source OLT 44-2 transitions to a sleep state (step Sa322).

[0389] Fig. 60 is a sequence diagram showing an example of a detailed flow of a sleep wake-up process executed by the wired NW system 200c in Modification 2 of the seventh embodiment. In Fig. 60, the same processes as those in Fig. 57 are denoted by the same reference numerals as those in Fig. 57, and the description thereof will be omitted.

[0390] After the processes of steps Sa501, Sa1801, and Sa1802 are performed, if the sleep release condition is satisfied, the real-time analysis unit 522c instructs the switching device 43b to perform optical path switching control and sleep control (step Sa2001). The switching device 43b receives the instructions transmitted from the management control device 50c.

[0391] The sleep control unit 532 of the switching device 43b transmits a sleep release notification to the OLT 44-2 based on the information included in the received instruction (step Sa2002). In response to receiving the sleep release notification, the OLT 44-2 transmits a sleep release response notification to the switching device 43b (step Sa2003).

[0392] The optical path switching control unit 531 of the switching device 43b determines the switching destination of the optical path from the information included in the received instruction (step Sa2004). The optical path switching control unit 531 of the switching device 43b notifies the concentrator 45 of the optical path switching destination information (step Sa2005). Thereafter, the processes from step Sa507 to step Sa520 are executed.

[0393] When the optical path switching is completed, the ONU 42 transmits an optical path switching completion notification to the switching device 43b (step Sa2006). When the optical path switching is completed, the OLT 44-1 transmits an optical path switching completion notification to the switching device 43b (step Sa2007). When the optical path switching is completed, the OLT 44-2 transmits an optical path switching completion notification to the switching device 43b (step Sa2008).

[0394] Eighth Embodiment The eighth embodiment differs from the fifth embodiment in that the cooperation information further includes information on transmission delay between the terminal 41 and each OLT 44 .

[0395] 61 is a diagram illustrating a configuration example of a wired network system 200d according to the eighth embodiment. The wired network system 200d according to the eighth embodiment includes one or more ONUs 42, a switching device 43, multiple OLTs 44, a concentrator 45, a core device 46, and a management control device 50d. The management control device 50d includes a collaboration information collection unit 51d, an analysis unit 52d, and a control unit 53.

[0396] The cooperation information collection unit 51d includes an acquisition unit 511 and a delay measurement unit 513d. The delay measurement unit 513d measures the transmission delay between the terminal 41 and each OLT 44. For example, the delay measurement unit 513d measures the transmission delay between the terminal 41 and each OLT 44 based on the RTT obtained as a result of transmitting a Ping. The delay measurement unit 513d outputs information on the propagation delay measured for each OLT 44 to the analysis unit 52d as cooperation information.

[0397] The analysis unit 52d includes an association information storage unit 521 and a real-time analysis unit 522d. Based on the association information, the real-time analysis unit 522d analyzes the communication status in the wired network system 200d, such as the amount of change in the number of connections of the OLT 44 per unit time. Specifically, the real-time analysis unit 522d divides the delay time by the number of currently accommodated terminals to estimate the delay time per unit. Furthermore, the real-time analysis unit 522d multiplies the number of accommodated terminals in other OLTs 44 by the delay time per unit of the target OLT 44, and determines to switch the optical path and go to sleep if the delay time does not exceed a threshold and the number of accommodated terminals in the OLT 44 is less than the number of terminals that the target OLT 44 can additionally accommodate.

[0398] Fig. 62 is a flowchart showing an example of the flow of sleep processing executed by the management control device 50d in the eighth embodiment. In Fig. 62, the same processes as those in Fig. 37 are denoted by the same reference numerals as in Fig. 37, and the description thereof will be omitted.

[0399] The delay measurement unit 513d measures the transmission delay between the terminal 41 and each OLT 44 (step Sa2101). The cooperation information collection unit 51d acquires cooperation information from each OLT 44 (step Sa2102). Specifically, the acquisition unit 511 acquires, as cooperation information, information on at least the number of accommodated terminals and information on the maximum number of accommodated terminals from each OLT 44. The cooperation information collection unit 51d accumulates the acquired cooperation information for each OLT 44 in the cooperation information accumulation unit 521 (step Sa2103). Specifically, the cooperation information collection unit 51d accumulates, as cooperation information, information on the transmission delay between the terminal 41 and each OLT 44 in the cooperation information accumulation unit 521, in addition to the cooperation information including, from each OLT 44, information on at least the number of accommodated terminals and information on the maximum number of accommodated terminals.

[0400] The real-time analysis unit 522d calculates the number of terminals that can be added to each OLT 44 based on the linkage information for each OLT 44 stored in the linkage information storage unit 521 (step Sa2104). Furthermore, the real-time analysis unit 522d estimates the delay time of each OLT 44 based on the information on the transmission delay between the terminal 41 and each OLT 44 stored in the linkage information storage unit 521 (step Sa2105).

[0401] The real-time analysis unit 522d determines whether an eighth switching condition is satisfied (step Sa2106). The eighth switching condition indicates that switching of the optical path between the ONU 42 and the OLT 44 is necessary, and for example, the number of terminals that can be added to a certain OLT 44 is greater than the number of terminals that can be accommodated by the OLT 44 that is the target of sleep determination, and the transmission delay does not exceed a threshold.

[0402] If the real-time analysis unit 522d determines that the eighth switching condition is satisfied (step Sa2106—YES), the process from step Sa105 onward is executed. On the other hand, if the real-time analysis unit 522d determines that the sixth switching condition is not satisfied (step Sa2106—NO), the process from step Sa107 onward is executed.

[0403] Fig. 63 is a flowchart showing an example of the flow of sleep processing executed by the management control device 50d in the eighth embodiment. The processing shown in Fig. 63 will be described by more specifically showing the processing shown in Fig. 62. In Fig. 63, processing that is the same as that in Fig. 38 is assigned the same reference numerals as in Fig. 38, and description thereof will be omitted.

[0404] The delay measurement unit 513d measures the transmission delay between the terminal 41 and each OLT 44 (step Sa2201). The acquisition unit 511 acquires, from each OLT 44, the maximum number of terminals that can be accommodated in each OLT 44, connected ONU information, and information on the number of terminals that can be accommodated, as cooperation information (step Sa2202).

[0405] The acquisition unit 511 accumulates the acquired association information for each OLT 44 in the association information accumulation unit 521 (step Sa2203). The real-time analysis unit 522d calculates the number of additional terminals that each OLT 44 can accommodate based on the association information for each OLT 44 accumulated in the association information accumulation unit 521 (step Sa2204). Furthermore, the real-time analysis unit 522d estimates the transmission delay per OLT 44 based on the information on the measured transmission delay between the terminal 41 and each OLT 44 (step Sa2205).

[0406] Specifically, the real-time analysis unit 522d calculates the transmission delay value t of the OLT 44-i obtained in the process of step Sa2201.ｉ The number of terminals accommodated in the OLT 44-i is U ｉ Divide by (t ｉ / u ｉ ) by which the transmission delay t per OLT 44-i is ｉ Next, the real-time analysis unit 522d assigns the value 1 to the constant i (step Sa2206). Next, the real-time analysis unit 522d assigns the value (i+1) to k (step Sa2207).

[0407] After that, the real-time analysis unit 522d ｉ -u ｉ >u ｋ , and T>t ｉ × (U ｉ +u ｋ ) is satisfied (step Sa2208). ｉ is the transmission delay t per OLT 44-i ｉ Represents U ｉ -u ｉ >u ｋ , and T>t ｉ × (ui + u ｋ ) is a specific example of the eighth switching condition. If the real-time analysis unit 522d determines that the eighth switching condition is satisfied (step Sa2208—YES), it executes the processes from step Sa207 onwards. On the other hand, if the real-time analysis unit 522d determines that the sixth switching condition is not satisfied (step Sa2208—NO), it executes the processes from step Sa209 onwards.

[0408] Figure 64 is a sequence diagram showing an example of a detailed flow of sleep processing executed by the wired network system 200d in the eighth embodiment. In Figure 64, the same processes as those in Figure 39 are assigned the same reference numerals as in Figure 39, and the description thereof will be omitted. In the description of Figure 64, it is assumed that the OLT 44-1 is the switching destination OLT and the OLT 44-2 is the switching source OLT. Here, the description will be given by referring to the switching destination OLT 44-1 and the switching source OLT 44-2.

[0409] The cooperation information collection unit 51d of the management control device 50d acquires cooperation information from the switching destination OLT 44-1 and the switching source OLT 44-2 at a predetermined period or at any timing (steps Sa2301 and Sa2302). Note that the cooperation information acquired in steps Sa2301 and Sa2302 includes at least information on the number of accommodated terminals, information on the maximum number of accommodated terminals, etc., as well as information on transmission delays between the terminal 41 and each OLT 44. The cooperation information collection unit 51d stores the acquired cooperation information in the cooperation information storage unit 521.

[0410] When the cooperation information is accumulated in the cooperation information accumulation unit 521, the real-time analysis unit 522d performs optical path switching and sleep control determination (step Sa2303). The optical path switching and sleep control determination in step Sa2303 is a determination of whether the eighth switching condition in step Sa2106 is satisfied. Here, it is assumed that the eighth switching condition in step Sa2106 is satisfied. If the eighth switching condition is satisfied, the real-time analysis unit 522d executes the processing from step Sa304 onwards.

[0411] Fig. 65 is a flowchart showing an example of the flow of a sleep release process executed by the management control device 50d in the eighth embodiment. In Fig. 65, the same processes as those in Fig. 40 are denoted by the same reference numerals as in Fig. 40, and the description thereof will be omitted.

[0412] The delay measurement unit 513d measures the transmission delay between the terminal 41 and each OLT 44 (step Sa2401). The acquisition unit 511 acquires the number of accommodated terminals and information on sleeping OLTs 44-k as cooperation information from each OLT 44 (step Sa2402). The acquisition unit 511 notifies the analysis unit 52d of the acquired number of accommodated terminals, information on sleeping OLTs 44-k, and information on transmission delay.

[0413] The real-time analysis unit 522d of the analysis unit 52d reads information on the maximum number of terminals that can be accommodated for each OLT 44 and information on the ONUs 42 that were connected to the sleeping OLT 44-k from the cooperation information accumulation unit 521 (step Sa2403).The real-time analysis unit 522d calculates the number of terminals that can be additionally accommodated for each OLT 44 based on the obtained cooperation information for each OLT 44 (step Sa2404).

[0414] Next, the real-time analysis unit 522d assigns the value 1 to the constant i (step Sa2405). ｉ <u ｉ , or T<t ｉ It is determined whether any of the following conditions is satisfied (step Sa2406). ｉ <u ｉ , or T<t ｉ The condition shown in is a specific example of the fourth sleep cancellation condition. ｉ means that the transmission delay between the terminal 41 and the OLT 44-i exceeds the threshold. That is, the transmission delay t ｉ means that the threshold has been exceeded.

[0415] The real-time analysis unit 522d determines whether the fourth sleep cancellation condition (for example, U ｉ <u ｉ , or T<t ｉ If it is determined that the above condition is satisfied (step Sa2406-YES), it is determined that it is necessary to switch the optical path and to wake up the sleeping OLT 44-k.

[0416] The real-time analysis unit 522d notifies the control unit 53 of the determination result. Then, the processing from step Sa406 onward is executed. Meanwhile, the real-time analysis unit 522d determines whether the fourth sleep cancellation condition (for example, U ｉ <u ｉ , or T<t ｉ If it is determined that the above condition is not satisfied (step Sa2406--NO), the process of step Sa408 is executed.

[0417] Fig. 66 is a sequence diagram showing an example of a detailed flow of a sleep release process executed by the wired network system 200d in the eighth embodiment. In Fig. 66, the same processes as those in Fig. 41 are assigned the same reference numerals as those in Fig. 41, and the description thereof will be omitted. In the description of Fig. 66, it is assumed that the OLT 44-2 is in a sleep state.

[0418] The OLT 44-2 is in a sleep state (step Sa501). The cooperation information collection unit 51d of the management control device 50d acquires cooperation information from the OLT 44-1 at a predetermined period or at any timing (step Sa2501). Note that the cooperation information acquired in step Sa2501 includes information on at least the number of accommodated terminals, information on the maximum number of accommodated terminals, etc., as well as information on transmission delays between the terminal 41 and each OLT 44. The cooperation information collection unit 51d stores the acquired cooperation information in the cooperation information storage unit 521.

[0419] When the cooperation information is accumulated in the cooperation information accumulation unit 521, the real-time analysis unit 522d performs optical path switching and sleep control determination (step Sa2502). The optical path switching and sleep control determination in step Sa2502 is based on whether the sleep cancellation condition is satisfied. Here, it is assumed that the sleep cancellation condition is satisfied. If the sleep cancellation condition is satisfied, the real-time analysis unit 522d executes the processing from step Sa504 onwards.

[0420] The wired network system 200d configured as described above can achieve the same effects as those of the fifth embodiment. Specifically, in the wired network system 200d, the management and control device 50d further acquires information on transmission delays between the terminal 41 and each OLT 44 as coordination information and determines whether or not optical path switching is necessary based on the coordination information. When it is determined that optical path switching is necessary, the management and control device 50d controls optical path switching between one or more ONUs 42 and multiple OLTs 44. Furthermore, after the optical path switching is performed, the management and control device 50d transitions OLTs 44 that are capable of sleeping into a sleep state. This allows for control of optical path switching and sleep while analyzing the load of each OLT 44. Therefore, it is possible to efficiently achieve power saving throughout the system.

[0421] (Variation 1 of the Eighth Embodiment) In the above-described embodiment, the configuration has been described in which the management control device 50d directly acquires the cooperation information from the OLT 44. The management control device 50d may acquire the cooperation information via another device (for example, a controller). In such a configuration, the wired NW system 200d is newly provided with a controller 60a, and the controller 60a is provided between the management control device 50d and the OLT 44.

[0422] The controller 60a acquires cooperation information from each OLT 44 at a predetermined period or at any timing. The controller 60a transmits the acquired cooperation information to the management control device 50d. The controller 60a may receive a sleep control instruction from the management control device 50d and transmit it to the switching source OLT. This configuration allows the management control device 50d to collect cooperation information via wireless communication.

[0423] (Variation 2 of Eighth Embodiment) In the above-described embodiment, the configuration has been shown in which the management control device 50d performs optical path switching control processing and sleep control processing. In contrast, the switching device 43 may be configured to perform optical path switching control processing and sleep control processing. In such a configuration, the switching device 43 includes a control unit 53, and the management control device 50d does not include a control unit 53. The real-time analysis unit 522d of the management control device 50d notifies the switching device 43 of the analysis result. Note that the real-time analysis unit 522d may notify the switching device 43 of the analysis result only when optical path switching and sleep control are performed. The control unit 53 of the switching device 43 performs optical path switching control processing and sleep control processing based on the analysis result notified from the management control device 50d.

[0424] Fig. 67 is a sequence diagram showing an example of a detailed flow of sleep processing executed by the wired NW system 200d in Modification 2 of the eighth embodiment. In Fig. 67, the same processes as those in Fig. 64 are denoted by the same reference numerals as those in Fig. 64, and the description thereof will be omitted.

[0425] After the processes from step Sa2301 to step Sa2303 are executed, if the eighth switching condition is satisfied, the real-time analysis unit 522d instructs the switching device 43b to perform optical path switching control and sleep control (step Sa2601). The switching device 43b receives the instructions transmitted from the management control device 50d.

[0426] The optical path switching control unit 531 of the switching device 43b determines the optical path switching destination from the information included in the received instruction (step Sa2602). The optical path switching control unit 531 notifies the concentrator 45 of the optical path switching destination information (step Sa2603). Thereafter, the optical path switching control unit 531 instructs the ONU 42 connected to the switching source OLT 44-2, the switching destination OLT 44-1, and the switching source OLT 44-2 to switch the optical path (step Sa2604). Thereafter, the processes from step Sa306 to step Sa317 are executed.

[0427] When the optical path switching is completed, the ONU 42 transmits an optical path switching completion notification to the switching device 43b (step Sa2605). The ONU 42 may also transmit the optical path switching completion notification to the management and control device 50d. When the optical path switching is completed, the switching destination OLT 44-1 transmits an optical path switching completion notification to the switching device 43 (step Sa2606). The ONU 42 may also transmit the optical path switching completion notification to the management and control device 50d.

[0428] When the sleep control unit 532 included in the switching device 43b receives an optical path switching completion notification from the destination of the optical path switching start notification, it transmits a sleep permission notification to the switching source OLT 44-2 (step Sa2607). When the switching source OLT 44-2 receives the sleep permission notification from the switching device 43, it transmits a sleep response notification to the switching device 43b (step Sa2608). After transmitting the sleep response notification, the switching source OLT 44-2 transitions to a sleep state (step Sa322).

[0429] Fig. 68 is a sequence diagram showing an example of a detailed flow of a sleep release process executed by the wired network system 200d in the second modification of the eighth embodiment. In Fig. 68, the same processes as those in Fig. 65 are denoted by the same reference numerals as those in Fig. 65, and the description thereof will be omitted. In the description of Fig. 65, it is assumed that the OLT 44-2 is in a sleep state.

[0430] After the processes of steps Sa501, Sa2501, and Sa2502 are performed, if the sleep release condition is satisfied, the real-time analysis unit 522d instructs the switching device 43b to perform optical path switching control and sleep control (step Sa2701). The switching device 43b receives the instructions transmitted from the management control device 50d.

[0431] The sleep control unit 532 of the switching device 43b transmits a sleep release notification to the OLT 44-2 based on the information included in the received instruction (step Sa2702). In response to receiving the sleep release notification, the OLT 44-2 transmits a sleep release response notification to the switching device 43b (step Sa2703).

[0432] The optical path switching control unit 531 of the switching device 43b determines the switching destination of the optical path from the information included in the received instruction (step Sa2704). The optical path switching control unit 531 of the switching device 43b notifies the concentrator 45 of the optical path switching destination information (step Sa2705). Thereafter, the processes from step Sa507 to step Sa520 are executed.

[0433] When the optical path switching is complete, the ONU 42 transmits an optical path switching completion notification to the switching device 43b (step Sa2706). When the optical path switching is complete, the OLT 44-1 transmits an optical path switching completion notification to the switching device 43b (step Sa2707). When the optical path switching is complete, the OLT 44-2 transmits an optical path switching completion notification to the switching device 43b (step Sa2708).

[0434] (Variation 1 common to the fifth to eighth embodiments) The wired network systems 200, 200a, 200c, and 200d may not include the switching device 13. In this configuration, each ONU 42 and each OLT 44 are connected in advance in a full-mesh network configuration. Furthermore, when switching an optical path, the optical path switching control unit 531 instructs the ONU 42 and OLT 44, which are targets of optical path switching, to switch the optical path. For example, the optical path switching control unit 531 transmits an optical path switching instruction (e.g., the process of step Sa305 in FIG. 39 ) to the ONU 42 and OLT 44, which are targets of optical path switching. Then, after receiving an optical path switching response notification from each of the ONU 42 to be switched and the OLT 44 to be switched, the optical path switching control unit 531 sends an optical path switching start notification (for example, the processing of step Sa312 in Figure 39) to the ONU 42 to be switched and the OLT 44 to be switched.

[0435] (Modification 2 Common to the Fifth to Eighth Embodiments) In the fifth to eighth embodiments, a configuration was shown in which the switching source OLT transitions to a sleep state when the management control devices 50, 50c, and 50d issue a sleep instruction to the switching source OLT as a trigger. The switching source OLT may be configured to transition to a sleep state autonomously, regardless of a sleep instruction from the management control devices 50, 50c, and 50d. In this configuration, the switching source OLT transitions to a sleep state autonomously when an autonomous sleep condition is satisfied. The autonomous sleep condition in Modification 2 common to the fifth to eighth embodiments is a condition for the switching source OLT to transition to a sleep state autonomously, such as no ONUs 42 connected to the switching source OLT (zero ONUs 42 connected to the switching source OLT) or no traffic flowing in for a certain period of time ΔT. In this configuration, the switching source OLT includes a sleep control unit. The sleep control unit included in the switching source OLT transitions the switching source OLT to a sleep state when the autonomous sleep condition is satisfied. Note that this configuration is also applicable to the case where the control unit 53 is included in the switching device 43b.

[0436] (Variant 3 common to the fifth to eighth embodiments) In addition to the number of accommodated terminals, the information collected by the management control devices 50, 50c, and 50d can also include the number of terminals in each OLT 44, the number of terminals in each ONU 42, the actual traffic volume, and the value obtained by multiplying the number of accommodated terminals by the average throughput of one terminal.

[0437] (Variation 4 common to the fifth to eighth embodiments) In each of the fifth to eighth embodiments shown in Figures 37, 38, 39, 44, 47, 48, 49, 52, 54, 55, 56, 59, 62, 63, 64, and 67, a configuration has been shown in which the OLT 44 to be put to sleep (for example, the switching source OLT) is put to sleep after the switching of the optical path is completed. Specifically, a configuration has been shown in which the management control devices 50, 50b, 50c, and 50d put the OLT 44 to be put to sleep (for example, the switching source OLT) to sleep after the switching of the optical path is completed (for example, after receiving an optical path switching completion notification).

[0438] 37, 38, 39, 44, 47, 48, 49, 52, 54, 55, 56, 59, 62, 63, 64, and 67, the optical path may be switched after the OLT 44 to be put to sleep (e.g., the switching source OLT) is put to sleep. When configured in this manner, the management control devices 50, 50b, 50c, and 50d execute optical path switching after putting the OLT 44 to be put to sleep (e.g., the switching source OLT) to sleep. For example, the management control devices 50, 50b, 50c, and 50d execute optical path switching by sending an optical path switching start notification to the target device after putting the OLT 44 to be put to sleep (e.g., the switching source OLT) to sleep. Here, "after putting the OLT 44 to be put to sleep (e.g., the source OLT) to sleep" may be after the management control device 50, 50b, 50c, 50d receives a sleep response notification from the OLT 44 to be put to sleep (e.g., the source OLT), or after sending a sleep permission notification to the OLT 44 to be put to sleep (e.g., the source OLT).

[0439] At least some or all of the functional units of the management control devices 20, 20b, 20c, 20d, 50, 50b, 50c, and 50d, or some or all of the functional units of the switching devices 13, 13b, 43, and 43b, are implemented as software by a processor such as a central processing unit (CPU) executing a program stored in a storage device having a non-volatile storage medium (non-transitory storage medium) and a storage unit. The program may be recorded on a computer-readable non-transitory storage medium. Examples of computer-readable non-transitory storage media include portable media such as flexible disks, magneto-optical disks, ROMs (read-only memories), and CD-ROMs (compact disc read-only memories), as well as storage devices such as hard disks built into computer systems.

[0440] At least some or all of the functional units of the management control devices 20, 20b, 20c, 20d, 50, 50b, 50c, and 50d, or some or all of the functional units of the switching devices 13, 13b, 43, and 43b, may be realized using hardware including electronic circuits (electronic circuits or circuitry) using, for example, LSIs (Large Scale Integrated circuits), ASICs (Application Specific Integrated Circuits), PLDs (Programmable Logic Devices), or FPGAs (Field Programmable Gate Arrays).

[0441] Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention.

[0442] The present invention can be applied to optical communication systems such as optical access systems.

[0443] REFERENCE SIGNS LIST 11...terminal, 12, 12-1 to 12-4...radio stations, 13, 13b, 43, 43b...switching devices, 14, 14-1 to 14-2...distributed stations, 15...aggregation stations, 16, 46...core devices, 20, 20b, 20c, 20d, 50, 50b, 50c, 50d...management control devices, 21, 21c, 21d, 51, 51c, 51d...coordination information collection units, 22, 52...analysis units, 23, 53...control units, 30a...wireless controllers, 42, 42-1 to 42-4...ONUs, 44, 44-1 to 44-2...OLTs, 45...line concentrators, 60a...controllers, 100, 100a, 100b, 100c, 100d...mobile network systems, 200, 200a, 200b, 200c, 200d... wired NW system, 211, 511... acquisition unit, 212c... remote station monitoring unit, 512c... monitoring unit, 213d, 513d... delay measurement unit, 221, 521... cooperation information accumulation unit, 222, 522... real-time analysis unit, 231, 531... optical path switching control unit, 232, 532... sleep control unit

Claims

1. one or more terminal accommodating stations for communicating with one or more terminals; a plurality of communication stations connected to the one or more terminal accommodating stations directly or via other devices; a cooperation information collection unit that acquires cooperation information indicating a state of communication between the communication station and the one or more terminals from the communication station; an optical path switching control unit that controls switching of the optical paths between the one or more terminal accommodating stations and the plurality of communication stations when it is determined based on the cooperation information that switching of the optical paths between the one or more terminal accommodating stations and the plurality of communication stations is necessary; a sleep control unit that causes a sleep-capable communication station to transition to a sleep state before or after switching of the optical path; A communication system comprising:

2. The one or more terminal accommodating stations are optical subscriber line terminals that terminate optical signals, the plurality of communication stations are optical line termination devices that terminate optical signals; The one or more terminals and the one or more terminal accommodating stations are connected by wire. The communication system according to claim 1 .

3. the other device is a switching device that switches optical paths between the one or more terminal accommodating stations and the plurality of communication stations; When 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 terminal accommodating stations and the multiple communication stations when it is determined based on the cooperation information that switching of the optical paths between the one or more terminal accommodating stations and the multiple communication stations is necessary; the switching device switches the optical path in response to an instruction from the optical path switching control unit, thereby switching the communication station to which the one or more terminal accommodating stations are connected; 3. A communication system according to claim 1 or 2.

4. the other device is a switching device that switches optical paths between the one or more terminal accommodating stations and the plurality of communication 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 an external device indicating that switching of the optical paths between the one or more terminal accommodating stations and the plurality of communication stations is necessary, and controls switching of the optical paths between the one or more terminal accommodating stations and the plurality of communication stations in response to the received notification.

3. A communication system according to claim 1 or 2.

5. The cooperation information includes at least information on the number of terminals accommodated by each communication station and information on the maximum number of terminals accommodated by each communication station, an analysis unit that determines, based on information on the number of terminals accommodated by each communication station and information on the maximum number of terminals accommodated by each communication station, that it is necessary to switch optical paths between the one or more terminal accommodating stations and the plurality of communication stations when all terminals accommodated by the communication station that is the subject of sleep determination can be accommodated by another communication station; the optical path switching control unit controls switching of the optical path so as to connect a terminal accommodating station connected to the communication station that is the subject of the sleep determination to the other communication station; the sleep control unit transitions the communication station that is the subject of the sleep determination to a sleep state as the communication station capable of sleeping; 3. A communication system according to claim 1 or 2.

6. The cooperation information further includes at least one of processing load information regarding a processing load for each communication station, or information regarding a transmission delay between the one or more terminals and the plurality of communication stations; the analysis unit determines, based on information on the number of terminals accommodated in each of the communication stations, information on the maximum number of terminals accommodated in each of the communication stations, and information on the processing load or transmission delay, that it is necessary to switch optical paths between the one or more terminal accommodating stations and the plurality of communication stations when all terminals accommodated in the communication station that is the subject of sleep determination can be accommodated in another communication station; 6. The communication system according to claim 5.

7. a communication station connected directly or via another device to one or more terminal accommodating stations that communicate with one or more terminals, and a cooperation information collection unit that acquires cooperation information indicating a state of communication between the one or more terminals and a communication station connected directly or via another device to the one or more terminals from the communication station; an analysis unit that determines whether or not switching of optical paths between the one or more terminal accommodating stations and a plurality of communication stations and sleep control are required based on the cooperation information; an optical path switching control unit that controls switching of the optical paths between the one or more terminal accommodating stations and the plurality of communication stations when it is determined that switching of the optical paths between the one or more terminal accommodating stations and the plurality of communication stations is necessary; a sleep control unit that causes a sleep-capable communication station to transition to a sleep state before or after switching of the optical path; A management control device comprising:

8. A communication station connected to a terminal accommodating station that communicates with a terminal, a transmission unit that transmits cooperation information indicating a state of communication with the terminal to a management control device; a receiving unit that receives an optical path switching instruction indicating that the management control device has determined that an optical path switching between the terminal accommodating station and the communication station is necessary based on the cooperation information; a sleep processing unit that transitions to a sleep state before or after the optical path is switched based on the optical path switching instruction; A communications station comprising:

9. acquiring, from a communication station connected directly or via another device to one or more terminal accommodating stations that communicate with one or more terminals, cooperation information indicating a state of communication between the one or more terminals and a communication station connected directly or via another device to the one or more terminal accommodating stations; when it is determined based on the cooperation information that switching of optical paths between the one or more terminal accommodating stations and a plurality of communication stations is necessary, controlling switching of optical paths between the one or more terminal accommodating stations and the plurality of communication stations; before or after the optical path is switched, a communication station capable of sleeping is shifted to a sleep state; Control methods.

10. one or more terminal accommodating stations for communicating with one or more terminals; a plurality of communication stations connected to the one or more terminal accommodating stations directly or via other devices; a cooperation information collection unit that acquires cooperation information indicating a state of communication between the communication station and the one or more terminals from the communication station; an optical path switching control unit that controls switching of the optical paths between the one or more terminal accommodating stations and the plurality of communication stations when it is determined based on the cooperation information that switching of the optical paths between the one or more terminal accommodating stations and the plurality of communication stations is necessary; a sleep control unit for causing a sleep-enabled communication station to transition to a sleep state before switching of the optical path; A communication system comprising:

11. one or more terminal accommodating stations for communicating with one or more terminals; a plurality of communication stations connected to the one or more terminal accommodating stations directly or via other devices; a cooperation information collection unit that acquires, from the communication station, cooperation information indicating a state of communication between the communication station and the one or more terminals, the cooperation information including any one of information on a processing load of the communication station, information on a processing delay of the communication station, and information on a transmission delay between the communication station and the one or more terminals; an optical path switching control unit that controls switching of the optical paths between the one or more terminal accommodating stations and the plurality of communication stations when it is determined based on the cooperation information that switching of the optical paths between the one or more terminal accommodating stations and the plurality of communication stations is necessary; a sleep control unit that causes a sleep-capable communication station to transition to a sleep state before or after switching of the optical path; A communication system comprising:

12. one or more terminal accommodating stations for communicating with one or more terminals; a plurality of communication stations connected to the one or more terminal accommodating stations directly or via other devices; a cooperation information collection unit that acquires cooperation information indicating a state of communication between the communication station and the one or more terminals from the communication station; an optical path switching control unit that controls switching of optical paths between the one or more terminal accommodating stations and the plurality of communication stations when all terminals accommodated in a communication station to be put to sleep among the plurality of communication stations can be accommodated in another communication station based on the cooperation information; a sleep control unit that transitions the communication station to be put into a sleep state before or after switching of the optical path is performed; A communication system comprising:

13. a communication station connected directly or via another device to one or more terminal accommodating stations that communicate with one or more terminals, and a cooperation information collection unit that acquires cooperation information indicating a state of communication between the one or more terminals and a communication station connected directly or via another device to the one or more terminals from the communication station; an analysis unit that determines whether or not switching of optical paths between the one or more terminal accommodating stations and a plurality of communication stations and sleep control are required based on the cooperation information; an optical path switching control unit that controls switching of the optical paths between the one or more terminal accommodating stations and the plurality of communication stations when it is determined that switching of the optical paths between the one or more terminal accommodating stations and the plurality of communication stations is necessary; a sleep control unit for causing a sleep-enabled communication station to transition to a sleep state before switching of the optical path; A management control device comprising:

14. a cooperation information collection unit that acquires, from a communication station, cooperation information indicating a state of communication between one or more terminal accommodating stations that communicate with one or more terminals and the one or more terminals, the cooperation information including any one of information on a processing load of the communication station, information on a processing delay of the communication station, and information on a transmission delay between the communication station and the one or more terminals; an analysis unit that determines whether or not switching of optical paths between the one or more terminal accommodating stations and a plurality of communication stations and sleep control are required based on the cooperation information; an optical path switching control unit that controls switching of the optical paths between the one or more terminal accommodating stations and the plurality of communication stations when it is determined that switching of the optical paths between the one or more terminal accommodating stations and the plurality of communication stations is necessary; a sleep control unit that causes a sleep-capable communication station to transition to a sleep state before or after switching of the optical path; A management control device comprising:

15. a communication station connected directly or via another device to one or more terminal accommodating stations that communicate with one or more terminals, and a cooperation information collection unit that acquires cooperation information indicating a state of communication between the one or more terminals and a communication station connected directly or via another device to the one or more terminals from the communication station; an analysis unit that determines that switching of optical paths between the one or more terminal accommodating stations and a plurality of communication stations and sleep control are necessary when all terminals accommodated in a communication station that is a sleep target can be accommodated in another communication station based on the cooperation information; an optical path switching control unit that controls switching of the optical paths between the one or more terminal accommodating stations and the plurality of communication stations when it is determined that switching of the optical paths between the one or more terminal accommodating stations and the plurality of communication stations is necessary; a sleep control unit that transitions the communication station to be a sleep target into a sleep state before or after switching of the optical path is performed; A management control device comprising:

16. Connects to a terminal host station that communicates with terminals hand, a transmission unit that transmits cooperation information indicating a state of communication with the terminal to a management control device; a receiving unit that receives an optical path switching instruction indicating that the management control device has determined that an optical path switching between the terminal accommodating station and the communication station is necessary based on the cooperation information; a sleep processing unit that transitions to a sleep state before the optical path is switched based on the optical path switching instruction; A communications station comprising:

17. A communication station connected to a terminal accommodating station that communicates with a terminal, a transmission unit that transmits, to a management control device, cooperation information indicating a state of communication with the terminal, the cooperation information including any one of information regarding a processing load of the communication station, information regarding a processing delay of the communication station, and information regarding a transmission delay between the communication station and the terminal; a receiving unit that receives an optical path switching instruction indicating that the management control device has determined that an optical path switching between the terminal accommodating station and the communication station is necessary based on the cooperation information; a sleep processing unit that transitions to a sleep state before or after the optical path is switched based on the optical path switching instruction; A communications station comprising:

18. acquiring, from a communication station connected directly or via another device to one or more terminal accommodating stations that communicate with one or more terminals, cooperation information indicating a state of communication between the one or more terminals and a communication station connected directly or via another device to the one or more terminal accommodating stations; when it is determined based on the cooperation information that switching of optical paths between the one or more terminal accommodating stations and a plurality of communication stations is necessary, controlling switching of optical paths between the one or more terminal accommodating stations and the plurality of communication stations; before switching of the optical path, a communication station capable of sleeping is put into a sleeping state; Control methods.

19. acquiring, from a communication station, cooperation information indicating a state of communication between one or more terminal accommodating stations that communicate with one or more terminals and a communication station that is connected directly or via another device to the one or more terminal accommodating stations, the one or more terminals, the cooperation information including any one of information regarding a processing load of the communication station, information regarding a processing delay of the communication station, and information regarding a transmission delay between the communication station and the one or more terminals; when it is determined based on the cooperation information that switching of optical paths between the one or more terminal accommodating stations and a plurality of communication stations is necessary, controlling switching of optical paths between the one or more terminal accommodating stations and the plurality of communication stations; before or after the optical path is switched, a communication station capable of sleeping is shifted to a sleep state; Control methods.

20. acquiring, from a communication station connected directly or via another device to one or more terminal accommodating stations that communicate with one or more terminals, cooperation information indicating a state of communication between the one or more terminals and a communication station connected directly or via another device to the one or more terminal accommodating stations; when all terminals accommodated in a communication station to be put to sleep among the plurality of communication stations can be accommodated in another communication station based on the cooperation information, controlling switching of optical paths between the one or more terminal accommodating stations and the plurality of communication stations; before or after the optical path is switched, the communication station to be put to sleep is shifted to a sleep state; Control methods.