Communication path determination device and communication path determination method

Abstract

A communication path determination device (10) determines a communication path on a communication network having a plurality of nodes (N) and a plurality of links (R) connecting the plurality of nodes by free-space optical communications, and is provided with an information processing unit (11). The information processing unit executes: acquisition processing (S11) for acquiring weather information and the communication quality of at least one link among the plurality of links; prediction processing (S12) for, on the basis of the weather information and the communication quality of the at least one link, predicting communication qualities of the plurality of links after a predetermined time; and determination processing (S13) for, on the basis of the predicted communication qualities, determining a communication path after the predetermined time.

Description

COMMUNICATION PATH DETERMINATION DEVICE, COMMUNICATION PATH DETERMINATION METHOD, COMMUNICATION DEVICE, COMMUNICATION CONTROL DEVICE, AND COMMUNICATION SYSTEM

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

[0002] Free-space optical communications (FSOC), which uses optical beams for communication, is being developed (see Patent Document 1). FSOC is expected to be a technology that can improve communication speeds in wireless communication networks.

[0003] Japanese Patent Application Publication No. 2008-28632

[0004] However, in FSOC, communication may be interrupted by meteorological events such as heavy rain, strong winds, etc. Heavy rain and strong winds are meteorological events that occur locally and in a short period of time, and are therefore difficult to forecast.

[0005] One aspect of the present invention has been made in consideration of the above-mentioned problems, and one example of its objective is to provide a communication path determination device, a communication path determination method, a communication device, a communication control device, and a communication system that can determine future communication paths taking into account the effects of local weather events.

[0006] A communication path determination device according to one aspect of the present invention is a communication path determination device that determines a communication path on a communication network having a plurality of nodes and a plurality of links that connect the plurality of nodes via optical space communication, and is equipped with an information processing unit, which performs an acquisition process that acquires weather information and the communication quality of at least one link among the plurality of links, a prediction process that predicts the communication quality of the plurality of links after a predetermined time based on the weather information and the communication quality of the at least one link, and a determination process that determines a communication path after the predetermined time based on the predicted communication quality.

[0007] A communication path determination method according to one aspect of the present invention is a communication path determination method for determining a communication path on a communication network having a plurality of nodes and a plurality of links connecting the plurality of nodes via optical space communication, and includes an acquisition process for acquiring weather information and the communication quality of at least one link among the plurality of links, a prediction process for predicting the communication quality of the plurality of links after a predetermined time based on the weather information and the communication quality of the at least one link, and a determination process for determining a communication path after the predetermined time based on the predicted communication quality.

[0008] A communication device according to one aspect of the present invention is a communication device for placement at one node on a communication network having a plurality of nodes and a plurality of links connecting the plurality of nodes via optical space communication, and is equipped with a communication device for placement at another node on the communication network, an optical transceiver for performing optical space communication, and an information processing unit, wherein the information processing unit performs an acquisition process for acquiring weather information and the communication quality of at least one link among the plurality of links, a prediction process for predicting the communication quality on the plurality of links after a predetermined time based on the weather information and the communication quality of the at least one link, and a notification process for notifying the predicted communication quality.

[0009] A communication control device according to one aspect of the present invention includes a second information processing unit that executes a determination process to determine a communication path after the predetermined time based on the predicted communication quality notified from the communication device.

[0010] A communication system according to one aspect of the present invention includes a communication device and a communication control device.

[0011] According to one aspect of the present invention, it is possible to provide a communication path determination device, a communication path determination method, a communication device, a communication control device, and a communication system that can determine future communication paths taking into account the effects of local weather events.

[0012] FIG. 1 is a block diagram showing an example of the configuration of a communication path determination device according to a first embodiment. FIG. 2 is a flow diagram showing an example of the processing flow in a communication path determination method according to the first embodiment. FIG. 3 is a schematic diagram showing an example of the configuration of a communication network according to a second embodiment. FIG. 4 is a block diagram showing an example of the configuration of a communication path determination device according to the second embodiment. FIG. 5 is a flow diagram showing an example of the processing flow in a communication path determination method according to the second embodiment. FIG. 6 is a schematic diagram showing an example of a moving weather event. FIG. 7 is a schematic diagram showing an example of the configuration of a communication system according to a third embodiment. FIG. 8 is a block diagram showing the hardware configuration of a computer that is an example of an implementation of a communication path determination device according to each exemplary embodiment of the present invention.

[0013] [First Embodiment] A first embodiment of the present invention will be described in detail with reference to the drawings. This embodiment is the basis for the embodiments described below.

[0014] (Configuration of communication path determination device) The configuration of a communication path determination device according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a block diagram showing an example configuration of a communication path determination device 10 according to a first embodiment. The communication path determination device 10 has an information processing unit 11, and determines a communication path on a communication network having a plurality of nodes and a plurality of links connecting the plurality of nodes by optical space communication. The information processing unit 11 executes a communication path determination method S10.

[0015] 2 is a flow diagram showing an example of the processing flow of the communication path determination method S10 according to the first embodiment. It is a block diagram showing an example of the configuration of a processing system controlled by a communication path determination device. The communication path determination method S10 includes an acquisition process (step S11) and a prediction process (step S12).

[0016] (1) Acquisition Process (Step S11) The information processing unit 11 acquires weather information and the communication quality of at least one link among a plurality of links.

[0017] (2) Prediction Process (Step S12) The information processing unit 11 predicts the communication quality of the plurality of links after a predetermined time based on the weather information and the communication quality of at least one link. For example, the information processing unit 11 estimates that a weather event has occurred at a specific location (e.g., the location of a link whose communication quality has deteriorated) based on the weather information and the communication quality of at least one link. Furthermore, the information processing unit 11 estimates the location of the weather event after a predetermined time based on the weather information and the communication quality of at least one link, and predicts the communication quality of the plurality of links after a predetermined time based on the estimated location.

[0018] (3) Determination Process (Step S13) The information processing unit 11 determines a communication path after a predetermined time based on the predicted communication quality.

[0019] As described above, the communication path determination device 10 according to this embodiment is a communication path determination device that determines a communication path on a communication network having a plurality of nodes and a plurality of links that connect the plurality of nodes via optical space communication, and is equipped with an information processing unit 11. The information processing unit 11 executes an acquisition process (step S11) that acquires weather information and the communication quality of at least one link Ri among the plurality of links, a prediction process (step S12) that predicts the communication quality of the plurality of links after a predetermined time based on the weather information and the communication quality of the at least one link, and a determination process (step S13) that determines a communication path after a predetermined time based on the predicted communication quality.

[0020] That is, the communication path determination device 10 estimates the location after a predetermined time from the weather event based on weather information and the communication quality of at least one link, thereby predicting the communication quality of multiple links after the predetermined time, and determines the communication path after the predetermined time based on the predicted communication quality. Therefore, the communication path determination device 10 according to this embodiment can determine future communication paths taking into account the influence of local weather events.

[0021] The communication path determination method S10 of this embodiment is a communication path determination method for determining a communication path on a communication network having a plurality of nodes and a plurality of links connecting the plurality of nodes via optical space communication, and includes an acquisition process (step S11) for acquiring weather information and the communication quality of at least one link among the plurality of links, a prediction process (step S12) for predicting the communication quality of the plurality of links after a predetermined time based on the weather information and the communication quality of the at least one link, and a determination process (step S13) for determining a communication path after the predetermined time based on the predicted communication quality.

[0022] That is, in the communication path determination method S10, by estimating the location after a predetermined time from a weather event based on weather information and the communication quality of at least one link, the communication quality of multiple links after the predetermined time is predicted, and a communication path after the predetermined time is determined based on the predicted communication quality. Therefore, the communication path determination method S10 according to this embodiment can determine a future communication path taking into account the influence of a local weather event.

[0023] Second Embodiment A second embodiment of the present invention will be described in detail with reference to the drawings. Note that components having the same functions as those described in the first embodiment are denoted by the same reference numerals, and their description will be omitted as appropriate.

[0024] Fig. 3 is a schematic diagram showing an example of the configuration of a communication network 100 according to the second embodiment. Fig. 4 is a block diagram showing an example of the configuration of a communication path determination device 110 according to the second embodiment.

[0025] The communication network 100 includes a plurality of nodes N and a plurality of links R that connect the plurality of nodes N by optical space communication. The communication network 100 further includes a communication path determination device 110 and a weather information server 120.

[0026] In optical space communication, communication is performed by transmitting and receiving optical beams between nodes N. For example, visible light or infrared light can be used as the optical beam. Optical space communication is characterized by ease of installation, high secrecy (the thin optical beam makes eavesdropping difficult), and high communication speed.

[0027] Here, optical free-space communication through the atmosphere is easily affected by atmospheric conditions. A localized meteorological event, such as heavy rain or strong winds, may degrade the communication quality of link R. For example, a localized and short-term communication failure (interruption of communication) may occur.

[0028] The communication path determination device 110 predicts the communication quality of each link R after a predetermined time (future) and determines the communication path after the predetermined time. For example, when transmitting information from node Ns to node Ne, by selecting link R, it is possible to appropriately select the path from node Ns to node Ne. Then, when a local communication interruption occurs in the communication network 100, the communication path determination device 110 determines a communication path that avoids link R where communication is interrupted. As a result, it is possible to maintain good communication conditions on the communication network 100.

[0029] The communication path determination device 110 can be arranged as a communication device at each node N. That is, the communication path determination device 110 functions as a communication device to be arranged at one node on a communication network 100 having a plurality of nodes N and a plurality of links R connecting the plurality of nodes by optical space communication. In the following, the description will be continued assuming that the communication path determination device 110 is arranged at each node N.

[0030] The communication path determination device 110 includes an information processing unit 111 , a communication control unit 112 , an optical transmitting / receiving unit 113 , and a storage unit 114 .

[0031] The information processing unit 111 executes a communication path determination method S100 (described later). The communication control unit 112 controls communication by the optical transmitting / receiving unit 113.

[0032] The optical transmitter / receiver 113 performs optical space communication between the node N where the communication path determination device 110 is located and an adjacent node N. The optical transmitter / receiver 113 functions as an optical transmitter / receiver for performing optical space communication with a communication device located at another node on the communication network 100.

[0033] At this time, the optical transceiver 113 can switch the node N with which to communicate. For ease of understanding, as shown in Fig. 3, two or more nodes can be selected as communication partners in two directions (x direction and y direction). For example, node Ni can switch the communication path by selecting four nodes as communication partners in the x direction and y direction.

[0034] The storage unit 114 stores the location information of the node N.

[0035] The weather information server 120 is a server device that stores weather information and provides it to the communication path determination device 110 via the communication network 100 or other communication means. The weather information is, for example, information on wind speed and rainfall in the area where the communication network 100 is located. Here, the wind speed information is preferably provided as a wind speed vector that also includes wind direction. The wind speed and rainfall information may be information on average wind speed and rainfall (average wind speed and average rainfall), but may also include information on wind speed and rainfall related to short-term strong winds and heavy rainfall (for example, localized strong winds and localized heavy rainfall).

[0036] (Communication path determination method S100) Fig. 5 is a flowchart showing an example of the processing flow of the communication path determination method S100 according to the second embodiment. Details of the communication path determination method S100 will be described below with reference to Fig. 5.

[0037] (1) Acquisition Process (Step S11) The information processing unit 111 acquires weather information and the communication quality of at least one link among the multiple links R.

[0038] The information processing unit 111 can acquire weather information (e.g., weather forecast information) from the weather information server 120. The weather information is, for example, information on average wind speed (e.g., average wind speed vector) and average rainfall. The weather information may also include information on maximum instantaneous wind speed or maximum instantaneous rainfall.

[0039] The information processing unit 111 can acquire the communication quality of the link R connected to the optical transceiver 113 (node ​​Ni) of its own device. The information processing unit 111 can provide the communication quality of the link R acquired from the optical transceiver 113 of its own device to another communication path determination device 110 via the communication network 100 or other communication means. On the other hand, the information processing unit 111 can acquire the communication quality of the link R connected to another node Nj from another communication path determination device 110.

[0040] The communication quality is, for example, the intensity of the optical beam received from link R, the bit error rate (BER), and the signal-to-noise ratio (SNR). Of these, the intensity of the optical beam can be easily used as an index of communication quality. In optical space communications, the intensity of the optical beam fluctuates depending on atmospheric conditions (for example, strong winds or heavy rain), and when the intensity of the optical beam decreases beyond a certain level, the bit error rate also deteriorates rapidly.

[0041] (2) Prediction Process (Step S12) The information processing unit 111 predicts the communication quality of the plurality of links after a predetermined time based on the weather information and the communication quality of at least one link (Step S12).

[0042] For example, in this prediction process, the information processing unit 11 estimates the location of a weather event that will degrade the communication quality of link R based on the acquired communication quality (of link R). Examples of such weather events include localized heavy rain and localized strong winds. Localized heavy rain and localized strong winds are difficult to forecast, and therefore estimating the location based on the communication quality of link R is effective.

[0043] More specifically, in the prediction process, the information processing unit 111 estimates the location of the weather event based on the location of the link whose acquired communication quality is below a predetermined standard. In other words, it can be considered that a local weather event has occurred near the link R whose communication quality is below a predetermined standard, causing a decrease in the communication quality of this link R.

[0044] In the prediction process, the information processing unit 111 estimates the moving direction and moving speed of the weather event, and predicts the communication quality at a plurality of links R after a predetermined time based on the estimated position, moving direction, and moving speed of the weather event. That is, the direction and speed at which the weather event will move from the estimated position are estimated, and the communication quality of the links R in the communication network 100 associated with the movement of this weather event is estimated. As the weather event moves, the communication quality of the links R whose communication quality has deteriorated due to the weather event improves, and the communication quality of the links R whose communication quality was good deteriorates.

[0045] The moving direction and moving speed of a weather event can be estimated based on the average wind speed vector. That is, the weather information includes information on the average wind speed vector, and the information processing unit 111 can estimate the moving direction and moving speed of a weather event based on this average wind speed vector.

[0046] A decrease in communication quality due to a weather event can be predicted, for example, by the maximum instantaneous wind speed or maximum instantaneous rainfall. That is, the weather information includes information on the maximum instantaneous wind speed or maximum instantaneous rainfall, and the information processing unit 111 may predict the communication quality on multiple links R after a predetermined time based on the estimated position, moving direction, moving speed, and maximum instantaneous wind speed or maximum instantaneous rainfall of the weather event.

[0047] 6 is a schematic diagram showing an example of a moving weather event. Hereinafter, the prediction of communication quality for each of the weather events of strong wind and heavy rain will be described with reference to FIG.

[0048] (a) Decrease in communication quality due to strong winds The following describes the calculation of the decrease in communication quality of link R due to strong winds. When a decrease in communication quality due to strong winds is found in link R connected to node Ni, the risk of strong winds at other node N changes. Then, the communication quality of the links connected to the node where the risk of strong winds has increased decreases.

[0049] Suppose node Ni has a link whose communication quality is below a predetermined standard. For example, suppose there is an interruption (e.g., a momentary blackout) in communication on link Rij of node Ni. In this case, the estimated instantaneous wind speed Wi' (vector) at node Ni is expressed as follows: Wi' = s(Δt) × (x, y) Δt: communication interruption time s(Δt): function indicating wind pressure stiffness at the position of node Ni (x, y): wind speed vector

[0050] The function s(Δt) is expressed, for example, as follows: s(Δt)=ki×Δt １／２ ki: Coefficient of wind pressure stiffness at node Ni

[0051] The strong wind risk area r(t) is expressed as follows: r(t) = vi + Wi' x t + mi vi: position vector of node Ni t: elapsed time from the start time t0 of communication interruption mi: expected margin of strong wind wave front at node Ni

[0052] The estimated margin mi can be expressed as follows: mi = ((α × γ) / β) × (1, -x / y) -u < γ < u α: Parameter representing the average wind speed β: Parameter representing the ratio of the maximum instantaneous wind speed to the average wind speed γ, u: Adjustment parameters for the strong wind wave front

[0053] The strong wind risk qj(t) at any node Nj is expressed as follows: qj(t) = δ / (vj - r(t)) ２ δ: risk intensity adjustment parameter vj: position vector of node Nj

[0054] Based on the strong wind risk qj(t) calculated as described above, the communication quality on link R can be estimated.

[0055] (b) Decrease in communication quality due to heavy rain The following describes the calculation of the decrease in communication quality of link R due to heavy rain. When a decrease in communication quality due to heavy rain is found in link R connected to node Ni, the risk of heavy rain at another node N changes. Then, the communication quality of the link connected to the node where the risk of heavy rain has increased decreases.

[0056] Suppose that node Ni has a link whose communication quality is below a predetermined standard. For example, suppose that communication is interrupted (e.g., momentary blackout) on link Rij of node Ni. In this case, the estimated instantaneous rainfall si' at node Ni is expressed as follows: si' = max (rth + φ × Δt, s) rth: rainfall threshold (rainfall amount estimated to cause communication to become impossible due to the effects of rainfall) φ: adjustment parameter Δt: communication interruption time s: rainfall (rainfall amount indicated in weather information, e.g., weather forecast)

[0057] The rainfall threshold rth can be calculated, for example, by the following formula: rth = rb × u rb: standard rainfall threshold, i.e., the amount of rain (e.g., 100 mm / h) at which communication is interrupted at a standard communication distance (e.g., 1 km) u: communication distance (distance between nodes, i.e., length of the link) The standard rainfall threshold rb can be determined by prior measurement.

[0058] The heavy rain risk area r(t) is expressed as follows: r(t) = vi + Wav × t + mi vj: position vector of node Ni Wav: average wind speed vector t: elapsed time from the start time t0 of communication interruption mi: estimated margin of heavy rain area

[0059] The estimated margin mi can be expressed as follows: mi = ((γ × s) / s') × (1, -x / y) -u < γ < u s': Estimated rainfall (rainfall estimated from communication interruption time Δt) γ, u: Adjustment parameters for heavy rain area Note that the estimated rainfall s' is set so as not to be smaller than the rainfall s (s' ≧ s).

[0060] The risk of heavy rain qj(t) at any node Nj is expressed as follows: qj(t) = δ / (vj - r(t)) ２ δ: risk intensity adjustment parameter vj: position vector of node Ni

[0061] Based on the heavy rain risk qj(t) calculated as described above, the communication quality on link R can be estimated.

[0062] (3) Determination Process (Step S13) The information processing unit 11 determines a communication path after a predetermined time based on the predicted communication quality.

[0063] For example, in the determination process, the information processing unit 111 can determine a communication path by excluding, from multiple links R, links whose predicted communication quality is lower than a predetermined standard. As shown in Fig. 6, as time t passes from t1 to t3, a weather event F(t) moves from F(t1) to F(t3). The information processing unit 111 can select communication path K1 instead of communication path K0 to avoid link R whose communication quality is predicted to deteriorate as the weather event F(t) approaches.

[0064] For ease of understanding, it is assumed here that the communication path determination device 110(i) is located at node Ni, receives information from node Ns, and forwards the information to node Ne. However, the communication path determination device 110(i) may be located at any node of the communication network 100.

[0065] On the other hand, in the determination process, the information processing unit 111 may set multiple communication costs C corresponding to each of multiple links R based on the predicted communication quality, and determine the communication route based on the multiple communication costs C.

[0066] An example of a method for determining a communication route based on the communication cost C of link R will be described below. The communication cost C(k, t) of link Rk can be defined, for example, as follows: C(k, t) = C(h, g, t) = Co(h, g) + qh(t) + qg(t) Co(h, g): communication cost between nodes Nh and Ng, which are the start and end points of link Rk k: identifier of link Rk t: time qh: risk at node Nh (risk of strong winds, risk of heavy rain, or total risk of strong winds and heavy rain) qg: risk at node Ng (risk of strong winds, risk of heavy rain, or total risk of strong winds and heavy rain)

[0067] The communication cost Co(h, g) is determined based on the communication distance L(h, g) and the congestion state D, and is expressed by the following formula, for example: Co(h, g) = μ × L(h, g) × D = μ × |vh - vg| × D μ: Adjustment parameter L(h, g): Communication distance between nodes Nh and Ng D: Congestion state of link Rk, for example, measured or estimated utilization rate of the link vh: Position vector of node Nh vg: Position vector of node Ng

[0068] The communication cost C(K, t) of a communication route K is expressed as the sum of the communication costs C(k, t) of the links R included in the communication route K: C(K, t) = ΣC(k, t)

[0069] The information processing unit 111 selects the communication route K that minimizes the communication cost C(K, t). Note that this selection can be performed using a known algorithm such as Dijkstra's algorithm.

[0070] As described above, the communication path determination device 110 predicts the communication quality of multiple links after a predetermined time based on weather information and the communication quality of at least one link, and determines a communication path after the predetermined time based on the predicted communication quality. Therefore, the communication path determination device 110 according to this embodiment can determine future communication paths taking into account the influence of local weather events.

[0071] [Third Embodiment] A third embodiment of the present invention will be described in detail with reference to the drawings. Note that components having the same functions as those described in the first embodiment are denoted by the same reference numerals, and their description will be omitted as appropriate.

[0072] 7 is a schematic diagram illustrating an example of the configuration of a communication system 200 according to the third embodiment. The communication system 200 includes a communication device 210a(i) and a communication control device 210b. The communication device 210a(i) is a communication device to be placed at one node Ni on a communication network including multiple nodes Ni and multiple links R that connect the multiple nodes Ni by optical space communication.

[0073] The communication device 210a(i) includes an information processing unit 211a and an optical transmitting / receiving unit 213. The optical transmitting / receiving unit 213 is an optical transmitting / receiving unit for performing optical space communication with a communication device disposed in another node Ni on the communication network.

[0074] The information processing unit 211a executes an acquisition process for acquiring weather information and the communication quality of at least one link among the multiple links, a prediction process for predicting the communication quality of the multiple links after a predetermined time based on the weather information and the communication quality of the at least one link, and a notification process for notifying the predicted communication quality.

[0075] The information processing unit 211a acquires the communication quality of the link R to which the own device (communication device 210a(i)) is connected, and notifies other devices (other communication devices 210a(j)).

[0076] The communication control device 210b has an information processing unit 211a, a communication control unit 212, and a storage unit 214. The information processing unit 211a executes a determination process to determine a communication path after a predetermined time based on the predicted communication quality notified from the communication device 210a(i). The communication control unit 212 controls communication by the communication device 210a(i) based on the determined communication path. The storage unit 214 stores location information of the node N.

[0077] The communication control device 210b may be placed in each node N, or may be placed in the communication network independently of the node N. For example, one communication control device 210b may be placed in the communication network to control communication in the communication device 210a(i) placed in each node N.

[0078] Here, the communication device 210a(i) predicts the communication quality of multiple links after a predetermined time and notifies the communication control device 210b of the predicted communication quality. In contrast, the communication device 210a(i) may notify the communication control device 210b of the communication quality of link R to which the communication device 210a(i) is connected, and the communication control device 210b may predict the communication quality of multiple links after a predetermined time based on weather information and the communication quality of the links notified by the communication device 210a(i).

[0079] [Example of Software Implementation] Some or all of the functions of the information processing unit 111 may be implemented by hardware such as an integrated circuit (IC chip), or may be implemented by software.

[0080] In the latter case, the information processing unit 111 is realized, for example, by a computer that executes instructions of a program, which is software that realizes each function. An example of such a computer (hereinafter referred to as computer C) is shown in FIG. 8. The computer C includes, for example, at least one processor C1 and at least one memory C2. The memory C2 stores a program P for operating the computer C as the information processing unit 111. In the computer C, the processor C1 reads and executes the program P from the memory C2, thereby realizing each function of the information processing unit 111.

[0081] The processor C1 may be, for example, a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), a micro processing unit (MPU), a floating point number processing unit (FPU), a physics processing unit (PPU), a tensor processing unit (TPU), a quantum processor, a microcontroller, or a combination thereof. The memory C2 may be, for example, a flash memory, a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof.

[0082] The computer C may further include a RAM (Random Access Memory) for expanding the program P during execution and for temporarily storing various data. The computer C may also include a communication interface for transmitting and receiving data to and from other devices. The computer C may also include an input / output interface for connecting input / output devices such as a keyboard, a mouse, a display, and a printer.

[0083] The program P can also be recorded on a non-transitory, tangible recording medium M that can be read by the computer C. Such a recording medium M can be, for example, a tape, a disk, a card, a semiconductor memory, or a programmable logic circuit. The computer C can acquire the program P via such a recording medium M. The program P can also be transmitted via a transmission medium. Such a transmission medium can be, for example, a communication network or broadcast waves. The computer C can also acquire the program P via such a transmission medium.

[0084] [Additional Note 1] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. For example, embodiments obtained by appropriately combining the technical means disclosed in the above-described embodiments are also included in the technical scope of the present invention.

[0085] [Additional Note 2] Part or all of the above-described embodiment can also be described as follows: However, the present invention is not limited to the following described aspects.

[0086] (Supplementary Note 1) A communication path determination device is a communication path determination device that determines a communication path on a communication network having a plurality of nodes and a plurality of links connecting the plurality of nodes by optical space communication, and includes an information processing unit, and the information processing unit executes an acquisition process that acquires weather information and the communication quality of at least one link among the plurality of links, a prediction process that predicts the communication quality of the plurality of links after a predetermined time based on the weather information and the communication quality of the at least one link, and a determination process that determines a communication path after the predetermined time based on the predicted communication quality.

[0087] (Supplementary Note 2) In the communication path determination device of Supplementary Note 1, in the determination process, the information processing unit determines the communication path by excluding from the plurality of links any link whose predicted communication quality is lower than a predetermined standard.

[0088] (Supplementary Note 3) In the communication path determination device of Supplementary Note 1, in the determination process, the information processing unit sets a plurality of communication costs corresponding to each of the plurality of links based on the predicted communication quality, and determines the communication path based on the plurality of communication costs.

[0089] (Supplementary Note 4) In the communication path determination device according to any one of Supplementary Notes 1 to 3, the information processing unit estimates a position of a meteorological event that degrades the communication quality of the link based on the acquired communication quality in the prediction process.

[0090] (Supplementary Note 5) In the communication path determination device of Supplementary Note 4, the meteorological event is a localized heavy rain or a localized strong wind.

[0091] (Supplementary Note 6) In the communication path determination device of Supplementary Note 4, the information processing unit, in the prediction process, estimates a position of the weather event based on the position of a link whose acquired communication quality is equal to or lower than a predetermined standard.

[0092] (Supplementary Note 7) In the communication path determination device of Supplementary Note 4, the information processing unit estimates a moving direction and a moving speed of the weather event in the prediction process, and predicts communication quality on the plurality of links after the predetermined time based on the estimated position, moving direction, and moving speed of the weather event.

[0093] (Supplementary Note 8) In the communication path determination device of Supplementary Note 7, the meteorological information includes information on an average wind speed vector, and the information processing unit estimates a moving direction and a moving speed of the meteorological event based on the average wind speed vector.

[0094] (Supplementary Note 9) In the communication path determination device of Supplementary Note 7, the meteorological information includes information on a maximum instantaneous wind speed or a maximum instantaneous rainfall, and the information processing unit predicts communication quality on the plurality of links after the predetermined time based on the position, moving direction, and moving speed of the estimated meteorological event, and the maximum instantaneous wind speed or maximum instantaneous rainfall.

[0095] (Supplementary Note 10) A communication path determination method is a communication path determination method for determining a communication path on a communication network having a plurality of nodes and a plurality of links connecting the plurality of nodes by optical space communication, and includes: an acquisition process for acquiring weather information and a communication quality of at least one link among the plurality of links; a prediction process for predicting communication quality on the plurality of links after a predetermined time based on the weather information and the communication quality of the at least one link; and a determination process for determining a communication path after the predetermined time based on the predicted communication quality.

[0096] (Supplementary Note 11) A communication device is a communication device to be placed at one node on a communication network having a plurality of nodes and a plurality of links connecting the plurality of nodes by optical space communication, and includes a communication device to be placed at another node on the communication network, an optical transceiver for performing optical space communication, and an information processing unit, wherein the information processing unit executes an acquisition process to acquire weather information and the communication quality of at least one link among the plurality of links, a prediction process to predict the communication quality of the plurality of links after a predetermined time based on the weather information and the communication quality of the at least one link, and a determination process to determine a communication path after the predetermined time based on the predicted communication quality.

[0097] (Supplementary Note 12) A communication device is a communication device to be placed at one node on a communication network having a plurality of nodes and a plurality of links connecting the plurality of nodes by optical space communication, and includes a communication device to be placed at another node on the communication network, an optical transceiver for performing optical space communication, and an information processing unit, wherein the information processing unit executes an acquisition process to acquire weather information and the communication quality of at least one link among the plurality of links, a prediction process to predict the communication quality of the plurality of links after a predetermined time based on the weather information and the communication quality of the at least one link, and a notification process to notify the predicted communication quality.

[0098] (Supplementary Note 13) In the communication device of Supplementary Note 12, the information processing unit acquires communication quality of a link to which the device itself is connected, and notifies the other device of the communication quality.

[0099] (Supplementary Note 14) The communication control device includes a second information processing unit that executes a determination process to determine a communication path after the predetermined time based on the predicted communication quality notified from the communication device of Supplementary Note 12.

[0100] (Supplementary Note 15) A communication system includes the communication device of Supplementary Note 12 and the communication control device of Supplementary Note 14.

[0101] (Supplementary Note 16) A communication path determination device is a communication path determination device that determines a communication path on a communication network having a plurality of nodes and a plurality of links connecting the plurality of nodes by optical space communication, and includes at least one processor, wherein the processor executes an acquisition process that acquires weather information and a communication quality of at least one link among the plurality of links, a prediction process that predicts the communication quality of the plurality of links after a predetermined time based on the weather information and the communication quality of the at least one link, and a determination process that determines a communication path after the predetermined time based on the predicted communication quality.

[0102] The communication path determination device may further include a memory that stores a program for causing the processor to execute the acquisition process, the prediction process, and the determination process. The program may also be recorded on a computer-readable, non-transitory, tangible recording medium.

[0103] REFERENCE SIGNS LIST 100 Communication network 110 Communication path determination device 111 Information processing unit 112 Communication control unit 113 Optical transmission / reception unit 114 Storage unit 120 Weather information server

Claims

1. A communication path determination device that determines a communication path on a communication network having a plurality of nodes and a plurality of links that connect the plurality of nodes by optical space communication, An information processing unit is provided, The information processing unit an acquisition process for acquiring weather information and communication quality of at least one link among the plurality of links; a prediction process for predicting communication quality of the plurality of links after a predetermined time based on the weather information and the communication quality of the at least one link; a determination process for determining a communication path after the predetermined time based on the predicted communication quality; A communication path determination device that executes the above.

2. In the determination process, the information processing unit 2. The communication path determination device according to claim 1, wherein the communication path is determined by excluding, from the plurality of links, links whose predicted communication quality is lower than a predetermined standard.

3. In the determination process, the information processing unit 2. The communication path determination device according to claim 1, further comprising: setting a plurality of communication costs corresponding to the plurality of links based on the predicted communication quality; and determining the communication path based on the plurality of communication costs.

4. In the prediction process, the information processing unit The communication path determination device according to claim 1 , further comprising: estimating a location of a weather event that degrades the communication quality of a link based on the acquired communication quality.

5. The communication path determination device according to claim 4 , wherein the weather event is a localized heavy rain or a localized strong wind.

6. In the prediction process, the information processing unit The communication path determination device according to claim 4 , wherein the location of the weather event is estimated based on the location of the link whose acquired communication quality is equal to or lower than a predetermined standard.

7. In the prediction process, the information processing unit Estimating the direction and speed of movement of the weather event; 5. The communication path determination device according to claim 4, further comprising: a predictor for predicting communication quality on the plurality of links after the predetermined time based on the estimated location, moving direction, and moving speed of the weather event.

8. The weather information includes information on average wind speed vectors, The communication path determination device according to claim 7 , wherein the information processing unit estimates a moving direction and a moving speed of the meteorological event based on the average wind speed vector.

9. The weather information includes information on a maximum instantaneous wind speed or a maximum instantaneous rainfall, 8. The communication path determination device according to claim 7, wherein the information processing unit predicts communication quality on the plurality of links after the predetermined time based on the location, direction of movement, and speed of movement of the estimated weather event, as well as the maximum instantaneous wind speed or maximum instantaneous rainfall.

10. A communication path determination method for determining a communication path on a communication network having a plurality of nodes and a plurality of links connecting the plurality of nodes by optical space communication, the method comprising: an acquisition process for acquiring weather information and communication quality of at least one link among the plurality of links; a prediction process for predicting communication quality of the plurality of links after a predetermined time based on the weather information and the communication quality of the at least one link; a determination process for determining a communication path after the predetermined time based on the predicted communication quality; A communication path determination method comprising: