How to support the setup of specific low-power radio equipment

Abstract

To set a channel and a position of a specific small power radio while avoiding a radio wave interference with the existed radio.SOLUTION: A setting support method of a specific small power radio, contains steps of: creating an occupation map to which an occupation probability that is obtained by a radio wave and is set so as to be higher as a reception continuous time is longer is set to each of a plurality of grids on the basis of a radio wave in each of the plurality of grids obtained by dividing a section and a measurement result obtained by measuring the reception continuous time; and determining a channel of a relay and a position of the relay so that the grid of which the occupation does not exist in a path from a start point to a termination point.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a method for supporting the setting of a specified low-power radio device. [Background technology]

[0002] The automatic collection system disclosed in Patent Document 1 includes multiple specified low-power radio devices. The multiple specified low-power radio devices form a multi-hop network. The multi-hop system is a system in which packets are transmitted from a slave device to a master device by each specified low-power radio device sequentially transmitting packets to adjacent specified low-power radio devices. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-56661 Summary of the Invention [Problem to be solved by the invention]

[0004] When constructing a multi-hop network, it is necessary to set the channel and location of the specified low-power radio device while avoiding radio interference with existing radio devices. [Means for solving the problem]

[0005] A configuration support method for specified low-power radio devices that solves the above problem is a configuration support method for specified low-power radio devices that supports the configuration of a plurality of specified low-power radio devices when constructing a multi-hop network by arranging the plurality of specified low-power radio devices in an area, and includes: creating an occupancy map for each channel, based on measurement results of measuring the radio wave channel and the radio wave reception duration for each of a plurality of grids that divide the area, and setting an occupancy probability for the radio waves for each of the plurality of grids such that the occupancy probability is set higher as the reception duration is longer; and determining the channel and position of a repeater that is to be arranged between the master unit and the slave unit of the plurality of specified low-power radio devices, when a grid of the occupancy map whose occupancy probability is less than a threshold is defined as a grid where communication is possible on the channel corresponding to the occupancy map, using a position of a slave unit that is a source of a packet among the plurality of specified low-power radio devices as a start point and a position of a master unit that is a destination of the packet among the plurality of specified low-power radio devices as an end point, so that there is no grid whose occupancy probability is equal to or greater than the threshold on a path from the start point to the end point.

[0006] Each specified low-power radio device has a set time limit for transmitting radio waves per unit time. Therefore, even if there are existing radio devices in the area where the specified low-power radio device is to be deployed, the same channel can be shared for a set period of time. For grids with short radio wave reception durations, the specified low-power radio device may be able to communicate by sharing the channel. By increasing the occupancy probability the longer the radio wave reception duration, it is possible to determine for each grid whether radio wave interference with existing radio devices is likely to occur. The configuration support method for specified low-power radio devices determines the repeater channel and repeater position so that there are no grids with an occupancy probability above a threshold on the route from the start point to the end point. By setting the repeater channel and repeater position accordingly, the specified low-power radio device channel and location can be set while avoiding radio wave interference with existing radio devices.

[0007] The configuration support method for the above-mentioned specific low-power radio device includes calculating a cost for each route when there are multiple routes, and determining the channel of the repeater and the position of the repeater means determining the channel of the repeater and the position of the repeater according to the route that minimizes the cost, and the cost may be higher as the number of repeaters increases.

[0008] The above-mentioned method for supporting the configuration of a specific low-power radio device includes calculating a cost for each route when there are multiple routes, and determining the channel of the repeater and the position of the repeater means determining the channel of the repeater and the position of the repeater according to the route that minimizes the cost, and the cost may be increased as the total value of the occupancy probability of the grids through which the route passes is higher.

[0009] The configuration support method for the above-mentioned specific low-power radio device includes calculating a cost for each route when there are multiple routes, and determining the channel of the repeater and the position of the repeater means determining the channel of the repeater and the position of the repeater according to the route that minimizes the cost, and the cost may be higher the longer the route. [Effects of the Invention]

[0010] According to the present invention, it is possible to set the channel and the position of a specified low-power radio device while avoiding radio wave interference with existing radio devices. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of an area where specific low-power radio devices are deployed. [Figure 2] 10 is a flowchart showing a method for supporting the setting of a specified low-power radio device. [Figure 3] FIG. 2 is a schematic diagram showing the arrangement positions of measuring instruments. [Figure 4] 1 is a schematic diagram showing a setting support device for a specified low-power radio device; [Figure 5] 10(a) to 10(d) are diagrams showing occupancy maps. [Figure 6] FIG. 1 shows a three-dimensional occupancy map. [Figure 7] (a) to (d) are diagrams showing specific low-power radio devices as nodes. [Figure 8] (a) to (c) are diagrams showing routes. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment of a method for supporting the setting of a specified low-power radio device will be described. <Specified low power radio equipment> As shown in Fig. 1, a plurality of specified low-power radio devices X1, X2, X3, X4, and X5 are located in an area A1. The area A1 may be, for example, a factory, an airport, a public facility, or a commercial facility. The area A1 includes a road R and buildings B1 and B2.

[0013] The specified low-power radio devices X1 to X5 are radio devices that communicate using a specified low-power radio system. The specified low-power radio system is a communication system that does not require a license under the Radio Act. The specified low-power radio system may be, for example, a communication system that communicates using the 920 MHz band. The specified low-power radio system that communicates using the 920 MHz band may be, for example, a communication system based on the Wi-SUN communication standard.

[0014] The plurality of specified low power radio devices X1 to X5 construct a multi-hop network. The multi-hop network is a network in which each of the specified low power radio devices X1 to X5 transmits a packet to its adjacent neighboring specified low power radio devices X1 to X5 in sequence, so that the packet is received by the specified low power radio device X2, which is the destination of the packet, from the specified low power radio device X1, which is the source of the packet. The specified low power radio device X1, which is the source of the packet, among the plurality of specified low power radio devices X1 to X5, is referred to as the slave device X1. The specified low power radio device X2, which is the destination of the packet, among the plurality of specified low power radio devices X1 to X5, is referred to as the master device X2. The specified low power radio devices X3 to X5, which are located between the master device X2 and the slave device X1, among the plurality of specified low power radio devices X1 to X5, are referred to as repeaters X3 to X5.

[0015] <How to support the setup of specific low-power radio equipment> When constructing a multi-hop network by placing a plurality of specified low-power radio devices X1 to X5 in the above-mentioned area A1, a configuration support method for specified low-power radio devices that supports the configuration of the plurality of specified low-power radio devices X1 to X5 will be described. The configuration support method for specified low-power radio devices determines the channels of the repeaters X3 to X5 and the positions of the repeaters X3 to X5.

[0016] 2, the setting support method for specified low-power radio devices X1 to X5 includes a preparation stage and a determination stage. The preparation stage is a stage for collecting information required to determine the channels of repeaters X3 to X5 and the positions of repeaters X3 to X5. The determination stage is a stage for determining the channels of repeaters X3 to X5 and the positions of repeaters X3 to X5 based on the information collected in the preparation stage.

[0017] <Preparation stage> 2 and 3, in step S1, measuring instruments M1 are placed in a plurality of grids G1 obtained by dividing an area A1. In the example shown in FIG. 3, the area A1 is divided into 36 grids G1. The grids G1 are square. The length of one side of the grid G1 can be set arbitrarily as long as it is shorter than the communication distance of the specified low-power radio devices X1 to X5.

[0018] The measuring device M1 may be placed only in those grids G1 that can receive radio waves of the specified low-power wireless system. For example, a grid G1 corresponding to a location where the walls of buildings B1 and B2 are present is a grid G1 that cannot receive radio waves of the specified low-power wireless system because the walls block the radio waves. Even in the grid G1 corresponding to buildings B1 and B2, if the measuring device M1 can be placed near a window of the building B1 or B2, the grid G1 is a grid G1 that can receive radio waves of the specified low-power wireless system. A grid G1 that corresponds to outdoors is a grid G1 that can receive radio waves of the specified low-power wireless system. In this way, based on the result of determining whether or not radio waves of the specified low-power wireless system can be received for each grid G1, the measuring device M1 may be placed only in those grids G1 that can receive radio waves of the specified low-power wireless system. The measuring device M1 may be placed in all grids G1. The measuring device M1 may be placed at the center of the grid G1 or at a position offset from the center of the grid G1. It is preferable that measuring device M1 is provided at a location where repeaters X3 to X5 can be placed. The placement of measuring device M1 is determined by the users of specified low-power radio devices X1 to X5.

[0019] The measuring instrument M1 is a device capable of receiving radio waves of a specified low-power radio system. That is, the measuring instrument M1 is capable of receiving radio waves that may interfere with radio waves transmitted by the specified low-power radio devices X1 to X5 when the specified low-power radio devices X1 to X5 are placed in the area A1. The measuring instrument M1 does not have to be capable of transmitting radio waves of a specified low-power radio system. The measuring instrument M1 is provided to measure the radio wave environment caused by existing radio devices. The measuring instrument M1 measures the radio wave channel and the duration of radio wave reception. In detail, the measuring instrument M1 measures the duration of radio wave reception, the number of times radio waves are received, and the radio wave reception strength for each radio wave channel. The duration of radio wave reception is the time during which radio waves are continuously received per unit time. The number of times radio waves are received is the number of times radio waves are received per unit time. The reception strength is the strength of the received radio waves. The reception strength may be the average value of radio waves received multiple times.

[0020] Next, in step S2, the measuring instrument M1 performs measurement. This allows measurement results to be obtained for each grid G1, measuring the radio wave channel and the duration of radio wave reception. In this embodiment, the measurement results include the number of times radio waves are received and the radio wave reception strength.

[0021] <Decision stage> 4, in the determination stage, a setting support device 10 for a specified low-power radio device executes processing based on the measurement results obtained in the preparation stage. The setting support device 10 is a computer. The setting support device 10 includes a processor and a storage unit. The setting support device 10 determines the channels of repeaters X3 to X5 and the positions of repeaters X3 to X5 by executing predetermined processing according to a program, for example.

[0022] As shown in FIGS. 2 and 5, in step S3, the setting assistance device 10 creates occupancy maps 21, 22, 23, and 24 based on the measurement results. The occupancy maps 21 to 24 are maps that show the radio wave environment caused by existing wireless devices in the area A1. The occupancy maps 21 to 24 are maps in which the occupancy probability caused by radio waves is set for each grid G2. The upper limit of the occupancy probability is 100%. The grid G2 of the occupancy maps 21 to 24 is the same as the grid G1 set in the area A1. The occupancy maps 21 to 24 are created for each channel.

[0023] The setting support device 10 creates occupancy maps 21-24 by plotting the measurement results obtained in the preparation stage on grid G2 for each channel. The setting support device 10 increases the occupancy probability the longer the duration of radio wave reception. The setting support device 10 increases the occupancy probability the more times radio waves are received. The setting support device 10 increases the occupancy probability the stronger the radio wave reception strength. The setting support device 10 also assigns occupancy probabilities to adjacent grids G2 according to the strength of the radio wave reception strength. The occupancy probabilities assigned to adjacent grids G2 increase as the radio wave reception strength increases. The setting support device 10 sets the occupancy probability to 100% for grids G2 in which a measuring instrument M1 is not placed.

[0024] As shown in FIG. 5, for example, assume that four occupancy maps 21 to 24 corresponding to four channels are obtained. In FIG. 5, the occupancy probability is represented by the shading of the grid G2. The darker the shading, the higher the occupancy probability. For convenience of illustration, the occupancy probability is represented in five stages, but the occupancy probability may also be a continuously changing value. The four channels include a first channel, a second channel, a third channel, and a fourth channel. Each channel has a different frequency bandwidth.

[0025] Figure 5(a) shows a first occupancy map 21 representing the occupancy probability of radio waves on the first channel. Figure 5(b) shows a second occupancy map 22 representing the occupancy probability of radio waves on the second channel. Figure 5(c) shows a third occupancy map 23 representing the occupancy probability of radio waves on the third channel. Figure 5(d) shows a fourth occupancy map 24 representing the occupancy probability of radio waves on the fourth channel.

[0026] As shown in Figure 6, a three-dimensional occupancy map 20 is obtained by overlapping four occupancy maps 21-24 so that grids G2 with the same coordinates overlap. The three-dimensional occupancy map 20 represents the position of the grid G2 using X and Y coordinates, and the channel using Z coordinate. Multiple grids G2 overlapping on the Z coordinate form a voxel.

[0027] As shown in FIG. 2, in step S4, the setting support device 10 generates a route from the starting point to the end point. The starting point is the position of the slave device X1 in the area A1. The end point is the position of the master device X2 in the area A1. At least one starting point is set. In this embodiment, there is one starting point, but there may be multiple starting points. One end point is set. The starting point and the end point are input by, for example, the user of the setting support device 10.

[0028] The setting assistance device 10 regards the three-dimensional occupancy map 20 as a map and generates a route in accordance with the following first to fourth conditions: The route is represented by a node graph with the specified low-power radio devices X1 to X5 as nodes and communications between the specified low-power radio devices X1 to X5 as edges.

[0029] First condition: A node cannot be placed on a grid G2 whose occupancy probability is higher than a threshold. Second condition: The edge cannot pass through a grid G2 whose occupancy probability is higher than a threshold. Third condition: The edge cannot be longer than a certain value.

[0030] Fourth condition: Only one node on the same channel can exist within a certain distance. The threshold value for the first condition and the threshold value for the second condition are the same value. The higher the occupancy probability, the more likely radio wave interference with existing radio devices will occur when specified low-power radio devices X1 to X5 are placed in grid G2. For this reason, a value that allows for radio wave interference is set as the threshold, and grid G2 with an occupancy probability below the threshold is defined as grid G2 where communication is possible on channels corresponding to occupancy maps 21 to 24. In other words, grid G2 with an occupancy probability equal to or greater than the threshold is defined as grid G2 where communication is not possible on channels corresponding to occupancy maps 21 to 24. The threshold value can be set to any value.

[0031] The predetermined value of the third condition is the communicable distance of the specified low-power radio devices X1 to X5. The certain distance in the fourth condition is a value determined by, for example, the communication method. 7 shows nodes N1 to N9 arranged in accordance with the first to fourth conditions, and edges E1 to E10 connecting the nodes N1 to N9. The nodes N1 to N9 are arranged in some voxels of the three-dimensional occupancy map 20. That is, the nodes N1 to N9 are arranged in grids G2 of the same coordinates in each of the occupancy maps 21 to 24. The node N1 represents the slave device X1. The grid G2 in which the node N1 is arranged is the start point G3. The node N9 represents the master device X2. The grid G2 in which the node N9 is arranged is the end point G4. The nodes N2 to N8 indicative of candidates for relays are arranged in each of the occupancy maps 21 to 24.

[0032] Of the edges E1 to E10 shown in each of the occupancy maps 21 to 24, the solid edges indicate that communication is possible using the channel corresponding to that occupancy map 21 to 24. Of the edges E1 to E10 shown in each of the occupancy maps 21 to 24, the dashed edges indicate that communication is not possible on the channel corresponding to that occupancy map 21 to 24 due to the fourth condition. Of the nodes N1 to N9 shown in each of the occupancy maps 21 to 24, the nodes N1 to N9 that are not connected by the edges E1 to E10 cannot communicate with each other on the channel corresponding to that occupancy map 21 to 24 due to the first to third conditions.

[0033] As shown in Figure 7(a), in the first occupancy map 21, node N1 and node N2 are connected by a solid edge E1. Node N1 and node N6 are connected by a solid edge E3. Node N4 and node N5 are connected by a solid edge E5. Node N3 and node N5 are connected by a solid edge E6. Therefore, nodes N1 and N2, nodes N1 and N6, nodes N4 and N5, and nodes N3 and N5 can communicate via the first channel.

[0034] 7(b), nodes N7 and N8 are connected by a solid edge E9 in the second occupancy map 22. Therefore, nodes N7 and N8 can communicate with each other via the second channel.

[0035] 7(c), in the third occupancy map 23, node N1 and node N4 are connected by a solid edge E4. Node N5 and node N8 are connected by a solid edge E7. Therefore, node N1 and node N4, and node N5 and node N8 can communicate via the third channel.

[0036] 7(d), in the fourth occupancy map 24, node N2 and node N3 are connected by a solid edge E2. Node N6 and node N7 are connected by a solid edge E8. Node N8 and node N9 are connected by a solid edge E10. Therefore, node N2 and node N3, node N6 and node N7, and node N8 and node N9 can communicate with each other via the fourth channel.

[0037] The route can be generated using a route search algorithm. The route search algorithm may be, for example, A* or RRT (Rapidly-exploring Random Tree). The route is formed by connecting the start point G3 to the end point G4 with solid edges E1 to E10.

[0038] 8, in this embodiment, three routes R1, R2, and R3 are generated. The three routes R1 to R3 include a first route R1, a second route R2, and a third route R3. Each of the routes R1 to R3 is a route in which there is no grid G2 with an occupancy probability equal to or greater than a threshold between a start point G3 and an end point G4.

[0039] As shown in FIG. 8(a), the first route R1 is a route passing through node N1 → edge E3 → node N6 → edge E8 → node N7 → edge E9 → node N8 → edge E10 → node N9.

[0040] As shown in FIG. 8(b), the second route R2 is a route passing through node N1 → edge E1 → node N2 → edge E2 → node N3 → edge E6 → node N5 → edge E7 → node N8 → edge E10 → node N9.

[0041] As shown in FIG. 8(c), the third route R3 is a route passing through node N1 → edge E4 → node N4 → edge E5 → node N5 → edge E7 → node N8 → edge E10 → node N9.

[0042] As shown in FIG. 2, in step S5, the setting support device 10 selects one route from the first route R1, the second route R2, and the third route R3. The setting support device 10 calculates the cost for each of the first route R1, the second route R2, and the third route R3. The setting support device 10 increases the cost the more nodes N2 to N8 each route R1, R2, and R3 passes through. Because the nodes N2 to N8 represent relays, the greater the number of relays, the higher the cost. The setting support device 10 increases the cost the longer the total length of the edges E1 to E10 of each route R1 to R3 from the start point G3 to the end point G4. Since the longer the total length of the edges E1 to E10, the longer the routes R1 to R3, the higher the cost. The setting support device 10 increases the cost the higher the total value of the occupancy probability of the grid G2 through which each route R1 to R3 passes.

[0043] 8(a), the number of nodes N2 to N8 passed by the first route R1 is 3. The total length of edges E1 to E10 of the first route R1 from the starting point G3 to the ending point G4 is 9.2. The total occupancy probability of grid G2 passed by the first route R1 is 1.

[0044] 8(b), the number of nodes N2 to N8 passed by the second route R2 is 4. The total length of edges E1 to E10 of the second route R2 from the starting point G3 to the ending point G4 is 10. The total occupancy probability of the grid G2 passed by the second route R2 is 2.

[0045] 8(c), the number of nodes N2 to N8 passed by the third route R3 is 3. The total length of edges E1 to E10 of the third route R3 from the starting point G3 to the ending point G4 is 9.2. The total occupancy probability of grid G2 passed by the third route R3 is 3.

[0046] In the above example, the total length of edges E1 to E10 is calculated by assuming that one side of grid G2 is 1. The sum of the occupancy probabilities of grid G2 passed by each of routes R1 to R3 is the number of times that the routes have passed through grid G2 with an occupancy probability higher than the lowest occupancy probability expressed on a five-level scale. In other words, when calculating the sum of the occupancy probabilities of grid G2 passed by each of routes R1 to R3, the lowest occupancy probability expressed on a five-level scale is considered to be 0, and any occupancy probability higher than the lowest occupancy probability is considered to be 1. The sum of the occupancy probabilities of grid G2 passed by each of routes R1 to R3 may be a value obtained by adding up the occupancy probabilities associated with the grid G2 passed by each of routes R1 to R3 as they are.

[0047] The setting support device 10 selects one route with the smallest cost. The number of nodes N2 to N8 passed by the second route R2 is greater than the number of nodes N2 to N8 passed by the first route R1. The number of nodes N2 to N8 passed by the second route R2 is greater than the number of nodes N2 to N8 passed by the third route R3. The total length of edges E1 to E10 of the second route R2 is longer than the total length of edges E1 to E10 of the first route R1. The total length of edges E1 to E10 of the second route R2 is longer than the total length of edges E1 to E10 of the third route R3. Therefore, the cost of the second route R2 is greater than the cost of the first route R1 and the cost of the third route R3. The sum of the occupancy probabilities of grids G2 passed by the first route R1 is lower than the sum of the occupancy probabilities of grids G2 passed by the third route R3. Therefore, the cost of the first route R1 is lower than the cost of the third route R3. Therefore, the setting assistance device 10 selects the first route R1 as the route with the smallest cost.

[0048] As shown in FIG. 2, in step S6, the setting support device 10 determines the channels of the repeaters X3 to X5 and the positions of the repeaters X3 to X5 according to the first route R1 that minimizes the cost. In the example shown in FIG. 8(a), the positions corresponding to the node N6, the node N7, and the node N8 are determined as the positions of the repeaters X3 to X5. Because the edge E3 is an edge in the first occupancy map 21, the channel used for communication between the repeater X3 arranged corresponding to the node N6 and the slave X1 arranged corresponding to the node N1 is determined to be the first channel. Because the edge E8 is an edge in the fourth occupancy map 24, the channel used for communication between the repeater X3 arranged corresponding to the node N6 and the repeater X4 arranged corresponding to the node N7 is determined to be the fourth channel. Because the edge E9 is an edge in the second occupancy map 22, the channel used for communication between the repeater X4 arranged corresponding to the node N7 and the repeater X5 arranged corresponding to the node N8 is determined to be the second channel. Since edge E10 is an edge in the fourth occupancy map 24, the channel used for communication between repeater X5, which is placed corresponding to node N8, and parent device X2, which is placed corresponding to node N9, is determined to be channel 4.

[0049] [Operation of this embodiment] The users of the specified low power radio devices X1 to X5 set the repeaters X3 to X5 in accordance with the channels and positions of the repeaters X3 to X5 determined in step S6. The users place repeater X3 in a position corresponding to node N6. The users place repeater X4 in a position corresponding to node N7. The users place repeater X5 in a position corresponding to node N8. Then, the users set the channels of the specified low power radio devices X1 to X5 to the channels determined in step S6.

[0050] [Effects of this embodiment] (1) The specified low-power radio devices X1 to X5 are each assigned a time period during which they can transmit radio waves per unit time. Therefore, even if there are existing radio devices in the area A1 where the specified low-power radio devices X1 to X5 are located, they can share the same channel by dividing the time period. For a grid G2 with a short radio wave reception duration, the specified low-power radio devices X1 to X5 may be able to communicate by sharing the radio wave channel. Therefore, by increasing the occupancy probability as the radio wave reception duration increases, it is possible to determine whether radio wave interference with existing radio devices is likely to occur for each grid G2. The specified low-power radio device configuration support method can determine the channels of repeaters X3 to X5 and the positions of repeaters X3 to X5 so that there are no grids G2 with an occupancy probability above a threshold on the route R1 to R3 from the start point G3 to the end point G4. By setting the channels of repeaters X3 to X5 and the positions of repeaters X3 to X5 in accordance with this, it is possible to set the channels of specified low-power radio devices X1 to X5 and the positions of specified low-power radio devices X1 to X5 while avoiding radio interference with existing radio devices.

[0051] (2) When multiple routes R1 to R3 exist, the cost is calculated for each of the routes R1 to R3. The channels of the repeaters X3 to X5 and the positions of the repeaters X3 to X5 are determined according to the route R1 to R3 that minimizes the cost. The cost increases as the number of repeaters X3 to X5 increases. This makes it possible to prevent the number of repeaters X3 to X5 from increasing.

[0052] (3) The cost increases as the total value of the occupancy probability of the grid G2 through which the routes R1 to R3 pass increases. Therefore, it is possible to select routes R1 to R3 that are less likely to cause radio wave interference. (4) The cost increases as the routes R1 to R3 become longer. If the routes R1 to R3 are long, the communication distance increases, which can cause packet errors and radio wave attenuation. By increasing the cost as the routes R1 to R3 become longer, the communication distance can be prevented from increasing.

[0053] (5) The occupancy probability is calculated based on the duration of radio wave reception, the number of times radio waves are received, and the strength of the radio wave reception. Compared to calculating the occupancy probability based only on the duration of radio wave reception, this method can more accurately grasp the impact of radio waves from existing wireless devices.

[0054] [Example of change] The embodiment can be modified as follows: The embodiment and the following modifications can be combined with each other to the extent that they are not technically inconsistent.

[0055] When multiple routes R1 to R3 exist, any of the routes R1 to R3 may be selected. That is, any route R1 to R3 may be selected without calculating the cost. For example, a route R1 to R3 on which relays X3 to X5 are easily located may be selected.

[0056] Step S2 may be performed by moving a mobile object equipped with a measuring instrument M1 to each grid G2. By moving the mobile object, measurement results can be obtained for each grid G2, measuring the radio wave channel and radio wave reception duration. The mobile object may be, for example, an aircraft.

[0057] The occupancy probability may be calculated from only the duration of radio wave reception. The occupancy probability may be calculated from the duration of radio wave reception and the number of times the radio wave is received. The occupancy probability may be calculated from the duration of radio wave reception and the radio wave reception strength.

[0058] There may be multiple slave devices X1. In this case, a route to the master device X2 may be generated for each of the slave devices X1. Then, repeaters X3 to X5 may be disposed at common portions of the routes from the slave devices X1 to the master device X2.

[0059] If only one route is generated in step S4, the process of step S5 does not need to be performed. The cost may be calculated based on at least one of the number of relays, the sum of the occupancy probabilities of the grids G2 through which the routes R1 to R3 pass, and the lengths of the routes R1 to R3. [Explanation of symbols]

[0060] A1...area, G2...grid, G3...starting point, G4...end point, R1, R2, R3...route, X1, X2, X3, X4, X5...specific low-power radio equipment, 21, 22, 23, 24...occupancy map.

Claims

1. 1. A method for supporting configuration of specified low-power radio devices when constructing a multi-hop network by arranging a plurality of specified low-power radio devices in an area, comprising: creating an occupancy map for each channel, in which an occupancy probability by the radio waves is set for each of the plurality of grids obtained by dividing the area, based on a measurement result obtained by measuring the radio wave channel and the duration of reception of the radio waves, the occupancy probability being set so as to become higher as the duration of reception is longer; a setting support method for a specified low power radio device, the method comprising: determining the channel of a repeater and the position of a repeater to be placed between a parent device and a child device among the plurality of specified low power radio devices, such that, when a starting point is a position of a child device among the plurality of specified low power radio devices that is a source of a packet, and an end point is a position of a parent device among the plurality of specified low power radio devices that is a destination of the packet, and when a grid among the grids in the occupancy map whose occupancy probability is less than a threshold is defined as a grid where communication is possible on the channel corresponding to the occupancy map, no grid whose occupancy probability is greater than or equal to the threshold exists on a path from the starting point to the end point.

2. When there are a plurality of the routes, a cost is calculated for each of the routes; Determining the channel of the repeater and the location of the repeater comprises determining the channel of the repeater and the location of the repeater along the route that minimizes the cost; 2. The method for supporting the setting of a specified low-power radio device according to claim 1, wherein the cost is increased as the number of repeaters increases.

3. When there are a plurality of the routes, a cost is calculated for each of the routes; Determining the channel of the repeater and the location of the repeater comprises determining the channel of the repeater and the location of the repeater along the route that minimizes the cost; 3. The method for supporting configuration of a specified low-power radio device according to claim 1, wherein the cost is increased as the total value of the occupancy probabilities of the grids through which the route passes increases.

4. When there are a plurality of the routes, a cost is calculated for each of the routes; Determining the channel of the repeater and the location of the repeater comprises determining the channel of the repeater and the location of the repeater along the route that minimizes the cost; 3. The method for supporting the setting of a specified low-power radio device according to claim 1, wherein the cost is increased as the route is longer.

Images