Communication system, management control device, and control method

Abstract

This communication system comprises: one or more wireless stations that perform wireless communication with one or more terminals; a plurality of distributed stations that are connected directly or through other devices to the one or more wireless stations; a cooperation information collection unit that acquires cooperation information indicative of the state of communication between the plurality of distributed stations and the one or more terminals at a prescribed period; an optical path switching control unit that, when it is determined that it is necessary to switch optical paths between the one or more wireless stations and the plurality of distributed stations on the basis of the cooperation information, controls switching of the optical paths between the one or more wireless stations and the plurality of distributed stations; and a sleep control unit that shifts a distributed station capable of sleep to a sleep state after the optical path switching is performed.　

Description

Communication system, management control device and control method

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

[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 be handed 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 or not to sleep, which may prevent overall optimization and limit the effectiveness of power saving.

[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 radio stations that perform wireless communication with one or more terminals; a plurality of distributed stations that are connected to the one or more radio stations directly or via other devices; a coordination information collection unit that acquires coordination information indicating the state of communication between the plurality of distributed stations and the one or more terminals at a predetermined period; an optical path switching control unit that controls the switching of the optical paths between the one or more radio stations and the plurality of distributed stations when it is determined based on the coordination information that switching of the optical paths between the one or more radio stations and the plurality of distributed stations is necessary; and a sleep control unit that transitions a distributed station that is capable of sleeping into a sleep state after the optical path switching has been performed.

[0007] One aspect of the present invention is a management and control device that includes: a coordination information collection unit that acquires coordination information indicating the state of communication between one or more terminals and multiple distributed stations that are connected directly or via other devices to one or more radio stations that perform wireless communication with 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 radio stations and the multiple distributed stations based on the coordination information; an optical path switching control unit that controls optical path switching between the one or more radio stations and the multiple distributed stations when it is determined that optical path switching between the one or more radio stations and the multiple distributed stations is necessary; and a sleep control unit that transitions a distributed station that is capable of sleeping into a sleep state after the optical path switching is performed.

[0008] One aspect of the present invention is a control method that acquires, at a predetermined period, coordination information indicating the state of communication between one or more terminals and multiple distributed stations that are connected directly or via other devices to one or more radio stations that perform wireless communication with one or more terminals, and when it is determined based on the coordination information that it is necessary to switch the optical path between the one or more radio stations and the multiple distributed stations, controls the switching of the optical path between the one or more radio stations and the multiple distributed stations, and transitions a distributed station that is capable of sleeping into a sleep state after the optical path switching has been performed.

[0009] According to the present invention, it is possible to increase the effect of power saving without deteriorating the communication quality.

[0010] 1 is a diagram for explaining an overview of the overall configuration and processing of a mobile NW system according to the present invention. FIG. 1 is a diagram illustrating an example of a configuration of a mobile NW system according to a first embodiment. FIG. 2 is a flowchart illustrating an example of the flow of sleep processing executed by a management control device according to the first embodiment. FIG. 3 is a flowchart illustrating an example of the flow of sleep processing executed by a management control device according to 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 according to the first embodiment. FIG. 5 is a flowchart illustrating an example of the flow of sleep release processing executed by a management control device according to 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 according to the first embodiment. FIG. 7 is a diagram illustrating an example of a configuration of a mobile NW system according to a modification of the first embodiment. FIG. 8 is a diagram illustrating an example of a configuration of a mobile NW system according to a modification 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 according to a modification of the first embodiment. FIG. 10 is a diagram illustrating an example of a configuration of a mobile NW system according to a second embodiment. FIG. 11 is a flowchart illustrating an example of the flow of sleep processing executed by a management control device according to 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 according to 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. 13 is a sequence diagram illustrating an example of a detailed flow of a sleep wake-up process executed by a mobile network system in a modified example of the fourth embodiment.

[0011] An embodiment of the present invention will be described below with reference to the drawings. (Overall Configuration and Processing Overview) Fig. 1 is a diagram for explaining the overall configuration and processing overview of a mobile network system according to the present invention. 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.

[0012] 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.

[0013] 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, a radio unit (RU) in the 5G communication standard.

[0014] 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.

[0015] 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.

[0016] 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").

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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."

[0026] (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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] The control unit 23 includes an optical path switching control unit 231 and a sleep control unit 232. The optical path switching control unit 231 determines the distributed node 14 to which the optical path is to be switched based on the analysis result of the real-time analysis unit 322, and instructs the switching device 13 to switch the optical path. For example, the optical path switching control unit 231 determines the 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.

[0032] 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 322 .

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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).

[0042] 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.

[0043] 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).

[0044] 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.

[0045] When i=1, k=2, it is expressed as follows: １ -u １ ⇒1000-100=900

[0046] Based on the above results, U １ -u １ >u ２The 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.

[0047] 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., distributed station 14-2) to point to the distributed station 14-i (e.g., 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., distributed station 14-2) (step S208).

[0048] 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

[0049] 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).

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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).

[0056] 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.

[0057] The optical path switching control unit 231 notifies the switching device 13 and the aggregation station 15 of the optical path switching destination information (step S304). The optical path switching destination information is information 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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).

[0062] 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.

[0063] 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).

[0064] 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).

[0065] 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.

[0066] 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).

[0067] 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 ｉThe 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] If i=1, U １ <u １The real-time analysis unit 222 determines whether the first sleep release condition (for example, U ｉ <u ｉ If 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] The optical path switching control unit 231 notifies the switching device 13 and the aggregation station 15 of the optical path switching destination information (step S506). When the switching device 13 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).

[0078] 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).

[0079] 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).

[0080] 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).

[0081] 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).

[0082] 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.

[0083] (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.

[0084] 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.

[0085] (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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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).

[0092] 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.

[0093] 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.

[0094] 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).

[0095] 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.

[0096] 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).

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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).

[0104] 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%.

[0105] 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.

[0106] 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.

[0107] 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).

[0108] 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).

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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).

[0121] 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%).

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] (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.

[0129] 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.

[0130] (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.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] 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).

[0136] 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.

[0137] 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.

[0138] 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).

[0139] 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.

[0140] 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).

[0141] (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.

[0142] 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.

[0143] 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.

[0144] 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.

[0145] 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).

[0146] 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.

[0147] 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.

[0148] 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.

[0149] 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).

[0150] 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).

[0151] 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.

[0152] 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.

[0153] 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.

[0154] 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.

[0155] 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.

[0156] 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.

[0157] 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.

[0158] 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).

[0159] 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.

[0160] 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.

[0161] 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.

[0162] 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.

[0163] 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.

[0164] 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.

[0165] 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.

[0166] (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.

[0167] 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.

[0168] (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.

[0169] 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.

[0170] 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.

[0171] 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.

[0172] 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.

[0173] 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).

[0174] 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.

[0175] 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.

[0176] 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).

[0177] 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.

[0178] 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).

[0179] 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 .

[0180] 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.

[0181] 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.

[0182] 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.

[0183] 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.

[0184] 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.

[0185] 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).

[0186] 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.

[0187] 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.

[0188] 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.

[0189] 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).

[0190] 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).

[0191] 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).

[0192] 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.

[0193] 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.

[0194] 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.

[0195] 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.

[0196] 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.

[0197] 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.

[0198] 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).

[0199] 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.

[0200] 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.

[0201] 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.

[0202] 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.

[0203] 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.

[0204] 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.

[0205] 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.

[0206] (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.

[0207] 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.

[0208] (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.

[0209] 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.

[0210] 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.

[0211] 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.

[0212] 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.

[0213] 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).

[0214] 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.

[0215] 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.

[0216] 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).

[0217] 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.

[0218] 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).

[0219] (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 central station 15 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 central station 14 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 central station 14 to switch the optical path, and after receiving an optical path switching response notification from the radio station 12 and the central 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 central station 14 to switch the optical path.

[0220] (Variation 2 Common to the First to Fourth Embodiments) In each embodiment, the configuration has been described in which the former remote station transitions to a sleep state when the management and control devices 20, 20c, and 20d issue a sleep instruction to the former remote station. The former remote 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 remote station transitions to a sleep state autonomously when an autonomous sleep condition is satisfied. The autonomous sleep condition is a condition for the former remote station to transition to a sleep state autonomously, such as no wireless station 12 being connected to the former remote station (no wireless station 12 being connected to the latter station) or no traffic flowing in for a certain period of time ΔT. In this configuration, the former remote station includes a sleep control unit. The sleep control unit included in the former remote station transitions the former remote station to a sleep state when the autonomous sleep condition is satisfied. Note that this configuration is also applicable when the control unit 23 is included in the switching device 13b.

[0221] 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.

[0222] At least some or all of the functional units of the management control devices 20, 20b, 20c, and 20d, or some or all of the functional units of the switching devices 13 and 13b, are realized as software by a processor such as a central processing unit (CPU) executing a program stored in a storage device having a non-volatile storage medium (non-transitory storage medium) and a storage unit. The program may be recorded on a computer-readable non-transitory storage medium. Examples of computer-readable non-transitory storage media include portable media such as flexible disks, magneto-optical disks, 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.

[0223] At least some or all of the functional units of the management control devices 20, 20b, 20c, and 20d, or some or all of the functional units of the switching devices 13 and 13b, may be realized using hardware including electronic circuits (electronic circuits or circuitry) using, for example, an LSI (Large Scale Integrated circuit), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array).

[0224] 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.

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

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

Claims

1. One or more wireless stations that wirelessly communicate with one or more terminals; a plurality of remote stations connected to the one or more wireless stations directly or via other devices; a coordination information collector that acquires coordination information used for either sleep determination or optical path switching determination from each of the plurality of remote stations; an optical path switching control unit that controls switching of the optical paths between the one or more radio stations and the multiple distributed stations when it is determined based on the cooperation information that switching of the optical paths between the one or more radio stations and the multiple distributed stations is necessary; a sleep control unit that transitions a remote station capable of sleeping to a sleep state after switching of the optical path; A communication system comprising:

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

3. the other device is a switching device that switches optical paths between the one or more radio stations and the multiple remote 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 radio stations and the multiple distributed stations is necessary, and controls switching of the optical paths between the one or more radio stations and the multiple distributed stations in response to the received notification. The communication system according to claim 1 .

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

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

5. The communication system according to claim 4.

6. the processing load information includes information on a memory usage rate of each of the remote stations; 6. The communication system according to claim 5.

7. a coordination information collector that acquires coordination information used for either sleep determination or optical path switching determination from each of a plurality of remote stations that are connected directly or via another device to one or more wireless stations that perform wireless communication with one or more terminals; an optical path switching control unit that controls switching of the optical paths between the one or more radio stations and the multiple distributed stations when it is determined based on the cooperation information that switching of the optical paths between the one or more radio stations and the multiple distributed stations is necessary; a sleep control unit that transitions a remote station capable of sleeping to a sleep state after switching of the optical path; A management control device comprising:

8. acquires, from each of a plurality of distributed stations connected directly or via another device to one or more wireless stations that perform wireless communication with one or more terminals, cooperation information used for either sleep determination or optical path switching determination; when it is determined based on the cooperation information that switching of optical paths between the one or more radio stations and the multiple distributed stations is necessary, controlling switching of optical paths between the one or more radio stations and the multiple distributed stations; After the optical path is switched, the distributed station capable of sleeping is put into a sleeping state. Control methods.

9. One or more wireless stations that wirelessly communicate with one or more terminals; a plurality of remote stations connected to the one or more wireless stations directly or via other devices; a coordination information collector that acquires coordination information used for determining at least an optical path switching from each of the plurality of remote stations; an optical path switching control unit that controls switching of the optical paths between the one or more radio stations and the multiple distributed stations when it is determined based on the cooperation information that switching of the optical paths between the one or more radio stations and the multiple distributed stations is necessary; A communication system comprising:

10. The communication system according to claim 9 , further comprising a sleep control unit that causes a remote station capable of sleeping to transition to a sleep state.

11. A remote station connected to a radio station that performs wireless communication with one or more terminals, a transmitter that transmits at least association information used for determining switching of the optical path to the management control device; a receiving unit that receives an instruction for switching an optical path between the radio station and the remote station, the instruction indicating that the management control device has determined that switching of an optical path between the radio station and the remote station is necessary based on the cooperation information; a sleep processing unit that transitions to a sleep state after the optical path is switched in accordance with the optical path switching instruction; A distributed station comprising:

12. A control method performed by a remote station connected to a radio station that performs wireless communication with one or more terminals, comprising: Transmitting at least coordination information used for determining switching of the optical path to a management control device; receiving an instruction to switch an optical path between the radio station and the remote station, the instruction indicating that the management control device has determined, based on the cooperation information, that it is necessary to switch an optical path between the radio station and the remote station; transitioning to a sleep state after the optical path is switched in accordance with the optical path switching instruction; Control methods.

13. a coordination information collector that acquires coordination information used for determining at least an optical path switching from each of a plurality of remote stations that are connected directly or via another device to one or more wireless stations that perform wireless communication with one or more terminals; an optical path switching control unit that controls switching of the optical paths between the one or more radio stations and the multiple distributed stations when it is determined based on the cooperation information that switching of the optical paths between the one or more radio stations and the multiple distributed stations is necessary; A management control device comprising:

14. The management control device according to claim 13, further comprising a sleep control unit that causes a remote station capable of sleeping to transition to a sleep state.

15. A remote station connected to a radio station that performs wireless communication with one or more terminals, a transmitter that transmits at least association information used for determining switching of the optical path to the management control device; a receiving unit that receives an instruction for switching an optical path between the radio station and the remote station, the instruction indicating that the management control device has determined that switching of an optical path between the radio station and the remote station is necessary based on the cooperation information; A distributed station comprising:

16. The remote station according to claim 15 , further comprising: a sleep processing unit that transitions to a sleep state.

17. acquires at least coordination information used for determining switching of optical paths from each of a plurality of distributed stations connected directly or via another device to one or more radio stations that perform wireless communication with one or more terminals; when it is determined based on the cooperation information that switching of the optical paths between the one or more radio stations and the multiple distributed stations is necessary, controlling switching of the optical paths between the one or more radio stations and the multiple distributed stations. Control methods.

18. Transitioning a sleep-enabled distributed station into a sleep state; 20. The control method according to claim 17.

19. A control method performed by a remote station connected to a radio station that performs wireless communication with one or more terminals, comprising: Transmitting at least coordination information used for determining switching of the optical path to a management control device; receiving an instruction to switch the optical path between the radio station and the remote station, the instruction indicating that the management control device has determined that switching of the optical path between the radio station and the remote station is necessary based on the cooperation information; Control methods.

20. Go to sleep if possible, 20. The control method of claim 19.

21. One or more wireless stations that wirelessly communicate with one or more terminals; a plurality of remote stations connected to the one or more wireless stations directly or via other devices; a coordination information collector that acquires, from each of the plurality of remote stations, coordination information used for determining at least optical path switching, the coordination information being a combination of information about the one or more radio stations connected to the plurality of remote stations and information about communications between the plurality of remote stations; an optical path switching control unit that controls switching of the optical paths between the one or more radio stations and the multiple distributed stations when it is determined based on the cooperation information that switching of the optical paths between the one or more radio stations and the multiple distributed stations is necessary; A communication system comprising:

22. a coordination information collector that acquires, from each of a plurality of distributed stations that are connected directly or via another device to one or more radio stations that perform wireless communication with one or more terminals, coordination information used for at least determining switching of an optical path, the coordination information being a combination of information about the one or more radio stations connected to the plurality of distributed stations and information about communications between the plurality of distributed stations; an optical path switching control unit that controls switching of the optical paths between the one or more radio stations and the multiple distributed stations when it is determined based on the cooperation information that switching of the optical paths between the one or more radio stations and the multiple distributed stations is necessary; A management control device comprising:

23. A remote station connected to a radio station that performs wireless communication with one or more terminals, a transmitter that transmits cooperation information, which is a combination of information on the wireless station to be connected and information on communication of the remote station, to a management control device, the cooperation information being used at least for determining switching of the optical path; a receiving unit that receives an instruction for switching an optical path between the radio station and the remote station, the instruction indicating that the management control device has determined that switching of an optical path between the radio station and the remote station is necessary based on the cooperation information; a sleep processing unit that transitions to a sleep state after the optical path is switched in accordance with the optical path switching instruction; A distributed station comprising:

24. One or more wireless stations that wirelessly communicate with one or more terminals; a plurality of remote stations connected to the one or more wireless stations directly or via other devices; a management control device connected to each of the plurality of remote stations; a controller that receives a sleep control instruction transmitted from the management control device and causes a remote station capable of sleeping to transition to a sleep state in response to the received sleep control instruction; Equipped with The management control device includes: a coordination information collector that acquires coordination information used for determining at least an optical path switching from each of the plurality of remote stations; an optical path switching control unit that controls switching of the optical paths between the one or more radio stations and the multiple distributed stations when it is determined based on the cooperation information that switching of the optical paths between the one or more radio stations and the multiple distributed stations is necessary; a sleep control unit that transmits the sleep control instruction to the controller; A communication system comprising:

25. One or more wireless stations that wirelessly communicate with one or more terminals; a plurality of remote stations connected to the one or more wireless stations via other devices; a switching device for switching connections between the one or more wireless stations and the plurality of remote stations; a coordination information collector that acquires coordination information used for determining at least an optical path switching from each of the plurality of remote stations; an optical path switching control unit that controls switching of the optical paths between the one or more radio stations and the multiple distributed stations when it is determined based on the cooperation information that switching of the optical paths between the one or more radio stations and the multiple distributed stations is necessary; Equipped with The switching device is The communication system further comprises a sleep control unit that causes a remote station capable of sleeping to transition to a sleep state.