Wireless Communication Method and Wireless Communication System

Abstract

A wireless communication method according to one embodiment of the present invention is for transmitting, by a plurality of node stations that are movable and are equipped with transmission buffers, data via switchable wireless communication routes, the method comprising: an acquisition step for acquiring, for each change in communication status, correspondence information sets corresponding to the data amounts transmitted by the respective node stations; a changing step for changing, on the basis of the acquired correspondence information sets, a cost value per unit of link speed between the plurality of node stations; a calculation step for calculating cost values between the plurality of node stations by using the changed cost value; and a determination step for determining a route in which the total calculated cost values becomes minimum, as a communication route.

Description

Technical Field

[0001] The present invention relates to a wireless communication method and a wireless communication system.

Background Art

[0002] In recent years, mobile communication systems have developed, and it has become possible to enjoy mobile services in most parts of the ground. In addition, ultra-coverage is one of the requirements in the fifth-generation (Beyond 5G) or sixth-generation mobile communication systems expected to be commercialized in the future.

[0003] Ultra-coverage means expanding the service area to places where the cost of laying existing base stations is high, such as mountains, seas, and the air, or where it is difficult to lay base stations, or places where it is difficult to lay base stations. In addition, strengthening the country against natural disasters is also required, and the emergence of a communication system that is resistant to ground disasters is desired.

[0004] In order to realize such a wireless communication system, a non-terrestrial network (NTN) using geostationary satellites, medium earth orbit (MEO) satellites, low earth orbit (LEO) satellites, high altitude platform stations (HAPS), unmanned aerial vehicles (UAVs), and drones has been in the spotlight (see, for example, Non-Patent Document 1).

[0005] In the NTN, satellites and HAPS connect communication links to each other to form a network, and further connect to the ground mobile network via a ground base station. Satellites and HAPS are equipped with a mobile base station function.

[0006] Then, the packets of the traffic transmitted by the terminal station are packet - transferred by the routing function to the satellites and HAPS connected to the terrestrial base station, and sent to the Internet network. Packets transmitted from the Internet network to other terminal stations also undergo similar processing by the routing function.

Prior Art Documents

Non - Patent Documents

[0007]

Non - Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] In a network such as NTN where there are large differences in delay and speed for each communication link, a method of calculating the cost value for each link and determining the route has been studied. For example, when determining a communication route in NTN, a route with the minimum total cost value calculated for each communication link is selected as the communication route.

[0009] However, in high - frequency band wireless communication used in satellites and HAPS, etc., when the communication situation fluctuates due to rainfall attenuation, etc., there is a problem that traffic may concentrate on some links with low cost values, resulting in congestion.

[0010] The present invention has been made in view of the above - described problems, and an object thereof is to provide a wireless communication method and a wireless communication system capable of efficiently performing wireless communication while reducing the concentration of traffic on a specific communication route even when the communication situation fluctuates among a plurality of wireless communication devices.

Means for Solving the Problems

[0011] A wireless communication method according to an embodiment of the present invention is a wireless communication method in which a plurality of mobile node stations having transmission buffers transmit data via a switchable wireless communication path. The method includes: an acquisition step of respectively acquiring correspondence information corresponding to the amount of data transmitted by each of the node stations every time the communication situation changes; a change step of changing a cost value per unit link speed among the plurality of node stations based on each of the acquired correspondence information; a calculation step of calculating cost values among the plurality of node stations using the changed cost values; and a determination step of determining, as a communication path, a path for which the total of the calculated cost values is minimized.

[0012] A wireless communication system according to an embodiment of the present invention is a wireless communication system in which a plurality of mobile node stations having transmission buffers transmit data via a switchable wireless communication path. The system includes: an acquisition unit that respectively acquires correspondence information corresponding to the amount of data transmitted by each of the node stations every time the communication situation changes; a change unit that changes a cost value per unit link speed among the plurality of node stations based on each of the correspondence information acquired by the acquisition unit; a calculation unit that calculates cost values among the plurality of node stations using the cost values changed by the change unit; and a determination unit that determines, as a communication path, a path for which the total of the cost values calculated by the calculation unit is minimized.

Advantages of the Invention

[0013] According to the present invention, even when the communication situation varies among a plurality of wireless communication devices, wireless communication can be efficiently performed while reducing the concentration of traffic on a specific communication path.

Brief Description of the Drawings

[0014]

Figure 1

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Figure 11

Figure 12

Mode for Carrying Out the Invention

[0015] First, the background leading to the present invention will be described with reference to FIG. 12. FIG. 12 is a diagram showing a configuration example of a wireless communication system 1. As shown in FIG. 12, the wireless communication system 1 includes, for example, base stations (ground base stations) 2-1 to 2-5 and node stations 3-1 to 3-5, and a plurality of terminal stations (ground terminal stations) 4-1 to 4-4 are respectively connectable.

[0016] The node stations 3-1 to 3-5 are wireless communication devices that move non-locally such as unmanned aerial vehicles or satellites, each having a mobile base station function, and for example, connecting communication links a to f to constitute an NTN.

[0017] When determining the communication path, the wireless communication system 1 selects, as the communication path, the path for which the sum of the cost values calculated for each communication link is minimized. The cost value is calculated by the following formula (1). For example, the link speed and the link delay are fixed values set by the user.

[0018]

Equation

[0019] For example, when the reference value of the speed is 100 Mbps, the cost value of a communication link with a speed of 10 Mbps is "10", and the cost value of a communication link with a speed of 100 Mbps is "1". That is, the cost value per unit link speed (for example, 1 Mbps) of a 10 Mbps communication link is 10 times that of a 100 Mbps communication link. Then, the wireless communication system 1 selects a faster communication link.

[0020] Also, when the reference value of the delay is 1 s, the cost value of a communication link with a delay of 10 ms is "100", and the cost of a communication link with a delay of 100 ms is "10". Then, the wireless communication system 1 selects a communication link with lower delay.

[0021] In this way, the wireless communication system 1 is configured to calculate the cost value by the above formula (1) and easily select a high-speed and low-delay communication link as the communication path.

[0022] In the example shown in FIG. 12, for example, assume that the cost value of communication link a is "1", the cost value of communication link b is "2", the cost value of communication link c is "4", the cost value of communication link d is "1", the cost value of communication link e is "30", and the cost value of communication link f is "30".

[0023] For example, when the communication links (feeder links) between the base station 2-1 and the node station 3-1, and between the base station 2-2 and the node station 3-2 are each blocked by a rain cloud or the like (when communication becomes impossible), traffic (data) is transferred to a node station having a feeder link capable of communicating with the base station (terrestrial base station).

[0024] At this time, the wireless communication system 1 selects a communication path with the minimum total cost value. That is, the terminal station 4-1 is connected to the base station 2-4 via communication links a and b with the minimum total cost value of 3 (=1 + 2). The terminal station 4-2 is connected to the base station 2-4 via the communication link b with the minimum total cost value of 2.

[0025] Therefore, traffic from the terminal station 4-1 and traffic from the terminal station 4-2 will concentrate on the communication link b, and congestion may occur.

[0026] Therefore, the wireless communication system 1a according to an embodiment described below is configured to be able to perform wireless communication efficiently while reducing the concentration of traffic on a specific communication path even when the communication status among a plurality of wireless communication devices fluctuates.

[0027] FIG. 1 is a diagram showing a configuration example of a wireless communication system 1a according to an embodiment. As shown in FIG. 1, the wireless communication system 1a according to an embodiment includes, for example, a plurality of base stations (terrestrial base stations) 5 and a plurality of node stations 6, and a plurality of terminal stations (terrestrial terminal stations) 7 are each connectable.

[0028] The node station 6 is a geostationary satellite (GEO), a medium earth orbit satellite (MEO), a low earth orbit satellite (LEO), a high altitude pseudo satellite (HAPS), a drone, an unmanned aerial vehicle (UAV), or an aircraft, etc.

[0029] Each of the node stations 6 connects communication links to each other and also connects a communication link to the base station 5, forming a network for each type of node station. For example, the node station network A includes a plurality of node stations 6 that are geostationary satellites, and the node station network B includes a plurality of node stations 6 that are unmanned aerial vehicles.

[0030] Also, each of the plurality of base stations 5 is connected to the network control device 8 and the Internet 12 via the mobile network 10. The network control device 8 acquires information from each node station 6 and the like via the mobile network 10. The network control device 8 may acquire information periodically, or may receive information from the node station 6 when an event such as feeder link disconnection occurs.

[0031] When specifying any one of a plurality of configurations such as the node station 6, it shall be described and distinguished as node station 6-1, node station 6-2, node station 6-3, ···

[0032] Each of the node stations 6 is a wireless communication device that moves non-locally, such as an unmanned aerial vehicle or a satellite equipped with a transmission buffer, and each has a mobile base station function including a routing function, and each connects communication links to form an NTN.

[0033] And when the wireless communication system 1a transmits data via a switchable wireless communication path by a plurality of node stations 6, it selects, as the communication path, the path for which the total cost value calculated for each communication link is minimized.

[0034] Figure 2 is a diagram showing a configuration example of the node station 6. As shown in Figure 2, the node station 6 has, for example, a plurality of inter-node station communication units 60, an inter-terminal station communication unit 61, an inter-base station communication unit 62, a traffic monitor 63, a feeder link monitor 64, and a route control unit 65.

[0035] The node-to-node communication unit 60 conducts wireless communication by connecting a communication link with another adjacent node station 6. The terminal-to-terminal communication unit 61 conducts wireless communication by connecting a communication link with a terminal station 7 within a predetermined communication area. The base-station-to-base-station communication unit 62 conducts wireless communication by connecting a communication link with a base station 5 within a predetermined communication area.

[0036] The traffic monitor 63 detects, for example, the traffic volume of each of the node-to-node communication unit 60, the terminal-to-terminal communication unit 61, and the base-station-to-base-station communication unit 62, and outputs each of the detected traffic volumes to the route control unit 65. Further, the traffic monitor 63 measures the usage status of the transmission buffer of the node station 6.

[0037] The feeder link monitor 64 monitors the feeder link conducted by the base-station-to-base-station communication unit 62, and outputs the result of the monitored feeder link to the route control unit 65.

[0038] Based on, for example, each of the traffic volume and the usage status of the transmission buffer input from the traffic monitor 63, and the result of the feeder link input from the feeder link monitor 64, the route control unit 65 calculates the cost value of each of the plurality of communication links of the wireless communication system 1a, and determines and controls the communication path (route) of the packet (data) to be transmitted in the wireless communication system 1a.

[0039] That is, the route control unit 65 performs calculation of the cost value, exchange of the cost value with another adjacent node station 6, and determination of the communication path of the traffic.

[0040] FIG. 3 is a diagram showing a configuration example of the route control unit 65. As shown in FIG. 3, the route control unit 65 includes, for example, a storage unit 650, an acquisition unit 652, a calculation unit 654, a determination unit 656, and a modification unit 658.

[0041] The storage unit 650 is a memory or the like, and stores, for example, data necessary for the route control unit 65 to calculate the cost values of the plurality of communication links and control the communication path, and outputs the stored data in response to access from the calculation unit 654 and the determination unit 656.

[0042] The acquisition unit 652 acquires the traffic volume output by the traffic monitor 63, the usage status of the transmission buffer, and the results of the feeder link output by the feeder link monitoring unit 64, etc., and outputs them to the calculation unit 654 and the change unit 658.

[0043] For example, the acquisition unit 652 acquires the corresponding information corresponding to the data volume transmitted by each node station 6 each time the communication status changes, and outputs it to the calculation unit 654 and the change unit 658.

[0044] More specifically, the acquisition unit 652 acquires the usage rate of the transmission buffer of each node station 6 as the corresponding information. Further, the acquisition unit 652 may acquire, as the corresponding information, the data volume obtained by subtracting the data volume newly input to the node station 6 due to the switching of the communication path from the data volume transmitted by the node station 6. Further, the acquisition unit 652 may acquire the C / N (carrier-to-noise ratio) of the data received by each node station 6 as the corresponding information.

[0045] The calculation unit 654 calculates the cost value using the data stored in the storage unit 650 and the corresponding information (traffic volume, etc.) acquired by the acquisition unit 652, and calculates the cost values between the plurality of node stations 6 using the calculated cost value. Then, the calculation unit 654 outputs the calculated cost values between the plurality of node stations 6 to the storage unit 650 and the determination unit 656.

[0046] Further, when the change unit 658 described later changes the cost value, the calculation unit 654 calculates the cost values between the plurality of node stations 6 using the cost value changed by the change unit 658.

[0047] The determination unit 656 determines the path for which the total of the data stored in the storage unit 650 and the cost value calculated by the calculation unit 654 is minimized as the communication path, and outputs information indicating the determined communication path to each unit constituting the node station 6.

[0048] Further, when the cost values of all communication paths calculated by the calculation unit 654 are equal to or higher than a predetermined threshold value, the determination unit 656 may determine a predetermined specific communication path as the communication path for specific data.

[0049] The change unit 658 changes the cost value per unit link speed among a plurality of node stations 6 based on each piece of correspondence information acquired by the acquisition unit 652, and outputs the changed cost value to the calculation unit 654.

[0050] That is, when the communication status of the communication link in the wireless communication system 1a fluctuates, the calculation unit 654 calculates the cost value among a plurality of node stations 6 using the cost value changed by the change unit 658 according to the communication status. Then, the determination unit 656 performs adaptive control for determining the communication path in the wireless communication system 1a according to the fluctuation of the communication status of the communication link.

[0051] Next, more specific operation examples (first operation example to fourth operation example) of the wireless communication system 1a will be described. FIG. 4 is a flowchart showing a first operation example of the wireless communication system 1a according to an embodiment.

[0052] As shown in FIG. 4, in step 100 (S100), the wireless communication system 1a determines, for example, whether the node station 6 performs centralized control of the determination of the communication path. When the node station 6 performs centralized control (S100: Yes), the process proceeds to the process of S102, and when the node station 6 does not perform centralized control (S100: No), the process proceeds to the process of S104.

[0053] In step 102 (S102), the node station 6 collects the usage rate of the transmission buffer from each node station 6.

[0054] In step 104 (S104), node station 6 checks the utilization rate of the transmission buffer of each node station 6. For example, node station 6 checks whether there is a change in the communication situation that requires a change in the cost value by using the utilization rate of the transmission buffer of each node station 6.

[0055] In step 106 (S106), node station 6 changes the cost value of each communication link according to the utilization rate of the transmission buffer.

[0056] In step 108 (S108), node station 6 calculates a communication path with the minimum total cost value of the communication links by using the changed cost value.

[0057] FIG. 5 is a diagram showing a first operation example of the wireless communication system 1a according to an embodiment. As shown in FIG. 5, for example, node station 6-1 transmits 1 Gbps of data to node station 6-2 via communication link a, and transmits the data to node station 6-3 via node station 6-2.

[0058] Node station 6 changes the cost value of the communication link according to the utilization rate of the transmission buffer. The transmission buffer utilization rate is calculated by the following formula (2).

[0059]

Equation

[0060] Also, the cost value at this time is calculated by the following formula (3).

[0061]

Equation

[0062] Here, assume that the number of input links to node station 6-2 is 1 and the utilization rate of the buffer is 75%. The traffic that can be input from communication link a to node station 6-2 is 1 Gbps × (1 - 0.75) = 0.25 Gbps.

[0063] In this case, the node station 6-2 changes the cost value with the link speed of the communication link a being 0.25 Gbps.

[0064] FIG. 6 is a flowchart showing a second operation example of the wireless communication system 1a according to an embodiment. As shown in FIG. 6, in step 200 (S200), the wireless communication system 1a determines, for example, whether the node station 6 performs centralized control of the determination of the communication path. When the node station 6 performs centralized control (S200: Yes), the process proceeds to the process of S202, and when the node station 6 does not perform centralized control (S200: No), the process proceeds to the process of S204.

[0065] In step 202 (S202), the node station 6 collects the states of the feeder links from each node station 6.

[0066] In step 204 (S204), the node station 6 detects the disconnection of the feeder link.

[0067] In step 206 (S206), the node station 6 calculates the communication path with the minimum total cost value and changes the communication path.

[0068] In step 208 (S208), the node station 6 changes the cost value of the communication route included in the new communication path.

[0069] FIG. 7 is a diagram showing a second operation example of the wireless communication system 1a according to an embodiment. As shown in FIG. 7, for example, the terminal station 7-1 attempts to transmit 1 Gbps of data to the base station 5-1 via the communication links a and b. At this time, when the feeder link (communication link b) between the node station 6-1 and the base station 5-1 is incommunicable due to rainfall or the like, after switching to a new communication path via the communication links a, c, and e, the wireless communication system 1a changes the cost value of the communication route included in the new communication path. In this case, the terminal station 7-1 transmits data to another base station (base station 5-2) via the node station 6-1 and the node station 6-2.

[0070] Specifically, node station 6 calculates the cost value according to the following formula (4).

[0071] [Number]

[0072] It is assumed that in the wireless communication system 1a, traffic of the link speed of the feeder link that has become communication-inaccessible at most (1 Gbps) is input to the communication link c included in the new communication path, and the cost value after the change is calculated with 4 Gbps obtained by subtracting 1 Gbps from the link speed (5 Gbps) of the communication link c as the link speed. That is, even if the link speed of the communication link c is 5 Gbps, node station 6-2 calculates the cost value with the link speed of the communication link c being 5 Gbps - 1 Gbps = 4 Gbps.

[0073] FIG. 8 is a flowchart showing a third operation example of the wireless communication system 1a according to an embodiment. As shown in FIG. 8, in step 300 (S300), the wireless communication system 1a detects a decrease in the reception C / N of the feeder link.

[0074] In step 302 (S302), node station 6 changes the feeder link speed according to the reception C / N

[0075] In step 304 (S304), node station 6 changes the cost value according to the changed feeder link speed.

[0076] In step 306 (S306), node station 6 calculates a communication path with the minimum total cost value using the changed cost value.

[0077] That is, in the third operation example, the wireless communication system 1a adaptively controls the link speed according to the reception C / N of the feeder link (when the reception C / N decreases due to rainfall or the like, the link speed is decreased to continue communication), and calculates the cost value according to the changed link speed.

[0078] FIG. 9 is a flowchart showing a fourth operation example of the wireless communication system 1a according to an embodiment. As shown in FIG. 9, in step 400 (400), the wireless communication system 1a calculates a communication path with the minimum total cost value.

[0079] In step 402 (S402), the node station 6 determines whether the minimum value of the total cost value is equal to or greater than a predetermined threshold. When the minimum value of the total cost value is equal to or greater than the predetermined threshold (S402: Yes), the node station 6 proceeds to the process of S404, and when the minimum value of the total cost value is less than the predetermined threshold (S402: No), the node station 6 proceeds to the process of S408.

[0080] In step 404 (S404), the node station 6 determines whether the data to be routed for transmission through the communication path with the minimum total cost value equal to or greater than the predetermined threshold corresponds to predetermined specific traffic. When the data corresponds to the specific traffic (S404: Yes), the node station 6 proceeds to the process of S406, and when the data does not correspond to the specific traffic (S404: No), the node station 6 proceeds to the process of S408.

[0081] In step 406 (S406), the node station 6 determines the communication path for transmitting the data corresponding to the specific traffic to a predetermined fixed communication path regardless of the cost value.

[0082] In step 208 (S208), the node station 6 determines the communication path for transmitting the data that does not correspond to the specific traffic to the communication path with the minimum cost value.

[0083] FIG. 10 is a diagram showing a fourth operation example of the wireless communication system 1a according to an embodiment. The wireless communication system 1a sets a threshold for the total cost value, and assumes that all communication paths are congested when the total cost value of any communication path is equal to or greater than the predetermined threshold. Then, the wireless communication system 1a communicates the specific traffic using a predetermined fixed communication path regardless of the cost value.

[0084] In the example shown in FIG. 10, assume that the communication links between node station 6-1 and base station 5-1, between node station 6-2 and base station 5-2, and between node station 6-3 and base station 5-3 are each unavailable for communication due to rain clouds or the like.

[0085] At this time, in order to transmit the data transmitted by terminal station 7-1, the wireless communication system 1a transfers the data toward either base station 5-4 or base station 5-5 that is communicable. For example, communication path X using communication links a and b, communication path Y using communication links c and d, and communication path Z using communication links e and f can be used for data transfer.

[0086] For example, assume that the total cost values of communication paths X, Y, and Z are as follows. Communication path X: 20 Communication path Y: 18 Communication path Z: 40

[0087] Also, assume that the threshold value of the total cost value for the communication path is 15. Here, when the data transmitted by terminal station 7-1 corresponds to predetermined specific traffic, since the total cost value of communication path Y, which is the communication path with the minimum total cost value, exceeds the threshold value of 15, the wireless communication system 1a determines the predetermined fixed communication path Z as the communication path for the data transmitted by terminal station 7-1 regardless of the total cost value.

[0088] Note that node station 6 determines whether it is specific traffic using, for example, QCI (QoS Class Identifier) from terminal station 7. Also, the wireless communication system 1a may be configured to operate by combining the operations of the first operation example to the fourth operation example described above.

[0089] Next, a modified example of the wireless communication system 1a will be described. FIG. 11 is a diagram illustrating the configuration of a modified example (network control device 8a) of the network control device 8 in the wireless communication system 1a according to an embodiment.

[0090] The network control device 8a has, for example, a collection unit 80 and a route control unit 65. The collection unit 80 collects the data transmitted via the mobile network 10 and outputs it to the route control unit 65. The data collected by the collection unit 80 is the same as the data obtained by the node station 6 described above.

[0091] For example, the collection unit 80 collects the usage status of the transmission buffer acquired by each node station 6 and the feeder link state.

[0092] In addition, the network control device 8a has the same function as the route control unit 65 provided in the node station 6 (see FIG. 3) and adaptively controls the communication path in the wireless communication system 1a. Therefore, the wireless communication system 1a does not necessarily need to have the function of each node station 6 to adaptively control the communication path as long as the network control device 8a has the function of adaptively controlling the communication path.

[0093] In this way, the wireless communication system 1a respectively acquires the correspondence information corresponding to the data amount transmitted by each node station 6 every time the communication situation changes, and based on each of the acquired correspondence information, changes the cost value per unit link speed among the plurality of node stations 6. Therefore, even if the communication situation among the wireless communication devices such as the plurality of base stations 5, node stations 6, and terminal stations 7 changes, it is possible to efficiently perform wireless communication while reducing the concentration of traffic on a specific communication path.

[0094] Note that each function of the base station 5, node station 6, terminal station 7, and network control devices 8 and 8a may be configured in part or in whole by hardware such as a PLD (Programmable Logic Device) or FPGA (Field Programmable Gate Array), or may be configured as a program executed by a processor such as a CPU.

[0095] For example, the wireless communication system 1a according to the present invention can be realized using a computer and a program, and the program can be recorded on a storage medium or provided through a network.

Explanation of Signs

[0096] 1, 1a... wireless communication system, 2, 5... base station, 3, 6... node station, 4, 7... terminal station, 8, 8a... network control device, 10... mobile network, 12... Internet network, 60... communication section between node stations, 61... communication section between terminal stations, 62... communication section between base stations, 63... traffic monitor, 64... feeder link monitoring section, 65... route control section, 80... collection section, 650... storage section, 652... acquisition section, 654... calculation section, 656... determination section, 658... change section

Claims

1. In a wireless communication method in which a plurality of node stations each having a transmission buffer and moving transmit data via a switchable wireless communication path, an acquisition step of respectively acquiring corresponding information corresponding to the amount of data transmitted by each of the node stations every time the communication situation changes; a change step of changing a cost value per unit link speed among the plurality of node stations based on each of the acquired corresponding information; a calculation step of calculating cost values among the plurality of node stations using the changed cost values; a determination step of determining, as a communication path, a path in which the total of the calculated cost values is minimized characterized by including.

2. In the acquisition step, acquiring, as the corresponding information, the usage rate of the transmission buffer of each of the node stations The wireless communication method according to claim 1, characterized by the above.

3. In the acquisition step, acquiring, as the corresponding information, the amount of data obtained by subtracting the amount of data newly input to the node station due to the switching of the communication path from the amount of data transmitted by the node station The wireless communication method according to claim 1 or 2, characterized by the above.

4. In the acquisition step, acquiring, as the corresponding information, the C / N of the data received by each of the node stations The wireless communication method according to any one of claims 1 to 3, characterized by the above.

5. In the determination step, when the cost values of all communication paths calculated by the calculation step are equal to or greater than a predetermined threshold value, determining a predetermined specific communication path as a communication path for specific data The wireless communication method according to any one of claims 1 to 4, characterized by the above.

6. In a wireless communication system in which a plurality of node stations each having a transmission buffer and moving transmit data via a switchable wireless communication path, an acquisition unit that respectively acquires corresponding information corresponding to the amount of data transmitted by each of the node stations every time the communication situation changes; a change unit that changes a cost value per unit link speed among the plurality of node stations based on each of the corresponding information acquired by the acquisition unit; a calculation unit that calculates cost values among the plurality of node stations using the cost values changed by the change unit; a determination unit that determines, as a communication path, a path in which the total of the cost values calculated by the calculation unit is minimized characterized by having.

7. The acquisition unit is, Each of the node stations acquires, as the corresponding information, at least any one of the usage rate of the transmission buffer of each node station, the C / N of the data received by each node station, and the data amount obtained by subtracting, from the data amount transmitted by the node station, the data amount newly input to the node station due to the switching of the communication path The wireless communication system according to claim 6, characterized in that [

8. ] The determination unit When the cost values of all the communication paths calculated by the calculation unit are equal to or greater than a predetermined threshold value, determines a predetermined specific communication path as the communication path for specific data The wireless communication system according to claim 6 or 7, characterized in that

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