JP2009005250A - Radio wave propagation analyzer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology capable of efficiently perform radio wave propagation analysis even though there exist many radio wave reception nodes. <P>SOLUTION: A position information acquisition part 11 acquires position information of a radio wave transmission node and a plurality of radio wave reception nodes. A radio wave propagation analyzer 12 performs the radio wave propagation analysis between the radio wave transmission node and the radio wave reception nodes. In that case, the radio wave propagation analyzer 12 does not perform the radio wave propagation analysis in the same analysis method on all of the radio wave reception nodes, but is able to change the analysis method of the radio wave propagation analysis for each radio wave reception node. For example, the high-precision electric wave propagation analysis is performed on the electric wave reception node which requires the high-precision electric wave propagation analysis, and the simple electric wave propagation analysis is performed on the electric wave reception node other than the above electric wave reception node. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a radio wave propagation analysis apparatus that performs radio wave propagation analysis between a radio wave transmission node and a plurality of radio wave reception nodes.

  In recent years, the field of use of wireless network technologies such as vehicle mutual information communication, mobile phones, and wireless LANs has expanded due to their usefulness.

  In general, a radio wave emitted from a transmission point of a radio wave such as a transmission antenna goes straight in a radial pattern around the transmission point. However, when there are obstacles (buildings, vehicles, etc.) beyond that, the radio waves are reflected, transmitted, and diffracted by the obstacles, spread in various directions, and attenuate.

  The above-mentioned radio wave propagation characteristics (reflection, transmission, diffraction, etc.) greatly affect the data communication performance of the wireless network system. Therefore, when manufacturing and selling products that include wireless network technology such as vehicle mutual information communication, mobile phones, and wireless LANs, how radio waves propagate in the target space as a pre-stage of manufacturing and sales. It is necessary to investigate how far radio waves can reach.

  Such a radio wave propagation characteristic is analyzed by computer simulation because it requires a large-scale device or requires a lot of labor and cost when measured using an experimental device or a prototype. Many techniques for propagation analysis are used.

  Such analysis methods include an electromagnetic field analysis method and a geometric optical method.

  In the electromagnetic field analysis method, Maxwell's electromagnetic field equation is solved by using, for example, an FDTD (Finite Difference Time Domain) method, and the electric field strength distribution is estimated based on the result. However, in this method, the calculation amount becomes enormous in the frequency band above the UHF band where the wavelength is shorter than the dimension of the model to be analyzed.

  The geometric optical method (ray tracing method) calculates electric field strength from trajectory information of a light beam transmitted from a transmission point and reaching a reception point, assuming that a radio wave is a geometric optical beam. The method of deriving the trajectory can be broadly classified into two methods: a mirror image point method (imaging method) and a ray launching method.

  In the mirror image point method, a reflection point is derived from a combination of a transmission point, a reception point, and all reflection surfaces to obtain a ray trajectory, and the ray trajectory can be obtained precisely. However, since the amount of calculation is proportional to the power of the number of reflections of the number of reflection surfaces, it becomes enormous when the shape of the analysis structure is complicated.

  In the ray launching method, light rays are discretely emitted from the transmission point at every transmission angle interval, the trajectory is sequentially tracked, and for each of the light rays that have reached the reception space defined around the reception point, A complex reception level is derived from propagation loss such as distance loss, polarization loss, and reflection loss, and the reception level is derived by phase-combining each ray. Therefore, since the amount of calculation processing is proportional to the number of reflecting surfaces, even when the shape of the analysis structure is complicated, it is small compared to the mirror image point method. However, since the reception point is defined in the reception space, the accuracy is poor compared to the mirror image point method that can accurately derive the ray trajectory.

  As a prior art of the above radio wave propagation analysis, in Patent Document 1, after deriving a plurality of light ray information, the space is divided into a plurality of pieces, and only the light ray information in the space where the reception space exists is read out and used. A radio wave propagation analysis method is disclosed.

  In Patent Document 2, an arrival chief ray that reaches the first reception space is specified from among a plurality of chief rays transmitted at the first transmission angle, and an angular interval smaller than the first transmission angle is set near the arrival chief ray. Discloses a radio wave propagation analysis method for transmitting a plurality of sub-beams and identifying a reaching sub-beam that reaches the second reception space.

  In Patent Document 3, a radio wave propagation path from a transmission point to a reception area (an area having a predetermined area from the reception point) is obtained by the ray launching method, and the radio wave is reflected only on an object surface existing in the radio wave propagation path. As an example, a radio wave propagation estimation program for obtaining a radio wave propagation path from a transmission point to a reception point by an imaging method is disclosed.

This type of analysis method requires a very long processing time if a high-accuracy analysis method is used when there are multiple radio wave receiving nodes. There is a problem of getting worse. Therefore, there is a demand for a technique that can efficiently perform radio wave propagation analysis even when there are many radio wave receiving nodes.
JP 2001-136130 A JP 2001-133494 A JP 2006-28785A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a technique capable of efficiently performing radio wave propagation analysis even when there are a large number of radio wave receiving nodes.

  In order to achieve the above object, the present invention adopts the following configuration.

  The radio wave propagation analysis device according to the present invention is a radio wave propagation analysis device that performs radio wave propagation analysis between a radio wave transmission node and a plurality of radio wave reception nodes, and acquires position information of the radio wave transmission node and the plurality of radio wave reception nodes. And a radio wave propagation analysis unit for performing radio wave propagation analysis between the radio wave transmission node and the radio wave reception node. The radio wave propagation analysis unit is used for radio wave propagation analysis from a plurality of analysis methods. An analysis method can be selected, and a radio wave propagation analysis method can be made different for each radio wave reception node.

  In the radio wave propagation analyzing apparatus according to the present invention, the radio wave propagation analysis method can be made different for each radio wave receiving node. As a result, for example, a radio wave receiving node that requires high accuracy analysis can use a high accuracy analysis method, and a radio wave reception node that does not require high accuracy analysis can use a simple analysis method. Even if there are many receiving nodes, efficient radio wave propagation analysis can be achieved.

It is preferable that the radio wave propagation analysis means makes the radio wave propagation analysis analysis method different between a specific radio wave reception node identified from the plurality of radio wave reception nodes and a radio wave reception node other than the specific radio wave reception node. . For example, a radio wave reception node that requires high-accuracy analysis is identified (the identified radio wave reception node is referred to as a specific radio wave reception node). A simple analysis method may be used for radio wave receiving nodes other than the node. As a result, an efficient radio wave propagation analysis can be achieved even if there are many radio wave receiving nodes.

  It is preferable that the radio wave propagation analysis unit varies the analysis method of the radio wave propagation analysis according to a distance between the radio wave transmission node and the radio wave reception node. For example, it may be necessary to know in detail the influence of radio waves on radio wave reception nodes that are closer to the radio wave transmission node (for example, products such as pre-crash safety systems in automobiles are simulated). Etc.) In this case, a radio wave receiving node that is close to the radio wave transmitting node uses a high-accuracy analysis method, and a radio wave receiving node that is far from the radio wave transmitting node uses a simple analysis method. Even if there are many, efficient radio wave propagation analysis can be achieved.

  It is preferable that the radio wave propagation analysis means makes the radio wave propagation analysis analysis method different between a radio wave reception node in a partial area that is a part of an area to be analyzed and a radio wave reception node outside the partial area. As a result, it is possible to separate an area that requires high-precision analysis from an area that is sufficient by simple analysis. Further, by changing the analysis method for each partial area, the user can easily change the analysis method, and efficient radio wave propagation analysis can be achieved even if there are many radio wave receiving nodes.

  The radio wave propagation analyzing means performs a radio wave propagation analysis only for a representative node of the partial area for each partial area that is a part of the analysis target area, and the result of the radio wave propagation analysis is performed on all the areas in the partial area. It is preferable to regard it as a result of radio wave propagation analysis for each of the radio wave receiving nodes. For example, when the radio wave propagation analysis is low accuracy (simple), there is no great difference in the results of the radio wave propagation analysis for each of a plurality of radio wave receiving nodes that are close to each other. Therefore, one of a plurality of radio wave reception nodes existing in the partial area, or a virtual radio wave reception node at the center position of the plurality of radio wave reception nodes, the center position of the partial area, or the like is set as the representative node. For the partial area, radio wave propagation analysis is performed only for the representative node. In other words, one-to-one (radio wave transmission node vs. radio wave reception node) radio wave propagation analysis is performed for radio wave reception nodes that require high-accuracy radio wave propagation analysis, and for other radio wave reception nodes. One-to-multiple radio wave propagation analysis is performed. Then, by considering the result as a radio wave propagation analysis result for each of the plurality of radio wave receiving nodes in the partial area, it is more efficient than performing radio wave propagation analysis for each of all the radio wave receiving nodes. Radio wave propagation analysis can be performed (this means that even if the analysis method used is the same, the analysis method of the radio wave propagation analysis is substantially different).

  The plurality of analysis methods preferably have different analysis algorithms. For example, a high-accuracy radio wave propagation analysis algorithm may be used for a radio wave reception node that requires high-accuracy radio wave propagation analysis, and a simple radio wave propagation analysis algorithm may be used for radio wave reception nodes other than the radio wave reception node. As a result, it is more efficient than using a highly accurate radio wave propagation analysis algorithm for all radio wave receiving nodes, and more accurate than using a simple radio wave propagation analysis algorithm for all radio wave receiving nodes. Propagation analysis can be achieved.

  The plurality of analysis methods preferably have different analysis parameters. For example, analysis parameters may be set in detail for a radio wave reception node that requires high-accuracy radio wave propagation analysis, and rough analysis parameters may be set for radio wave reception nodes other than the radio wave reception node. This enables more efficient radio wave propagation analysis than setting detailed analysis parameters for all radio wave receiving nodes and more accurate than setting rough analysis parameters for all radio wave receiving nodes. I can plan.

Further, the present invention may be regarded as a radio wave propagation analysis apparatus having at least a part of the above means, or a radio wave propagation analysis method including at least a part of the above processing, or a radio wave propagation analysis for realizing such a method. It can also be understood as a program or a storage medium storing the program. Each of the above means and processes can be combined with each other as much as possible to constitute the present invention.

  In the radio wave propagation analyzing apparatus according to the present invention, the radio wave propagation analysis method can be made different for each radio wave receiving node. As a result, for example, a radio wave receiving node that requires high accuracy analysis can use a high accuracy analysis method, and a radio wave reception node that does not require high accuracy analysis can use a simple analysis method. Even if there are many receiving nodes, efficient radio wave propagation analysis can be achieved.

  Exemplary embodiments of the present invention will be described in detail below with reference to the drawings.

<Device configuration>
FIG. 1 is a block diagram showing a functional configuration of a radio wave propagation analyzing apparatus according to an embodiment of the present invention. This radio wave propagation analyzer is a device that performs radio wave propagation analysis (simulation of radio wave propagation) between a radio wave transmission node and a plurality of radio wave reception nodes. For example, a vehicle equipped with a vehicle mutual information communication function is commercialized. Therefore, it is used for simulating whether the function operates normally (investigating radio wave propagation characteristics) or the like. In the present embodiment, a case where the radio wave transmission node and the radio wave reception node are vehicles (radio wave transmission vehicles, radio wave reception vehicles) will be described. Note that this radio wave propagation analyzer is not limited to the radio wave propagation characteristics between vehicles, but the radio waves between various radio wave transmission nodes and radio wave reception nodes, such as between a person carrying a communication terminal and a vehicle equipped with a communication function. It can be used to investigate propagation characteristics.

  The radio wave propagation analysis apparatus includes a plurality of functional elements shown in FIG. 1, that is, a position information acquisition unit 11, a radio wave propagation analysis unit 12, a result storage unit 13, and a display unit 14. In the present embodiment, these functional elements are realized by an arithmetic processing unit of a computer executing software (program) and controlling hardware resources such as a hard disk, a memory, and a display as necessary. However, these functional elements may be configured by a dedicated chip.

  The position information acquisition unit 11 has a function of acquiring position information (position information) of the radio wave transmitting vehicle and the plurality of radio wave receiving vehicles. The position information acquisition unit 11 may request the user to input position information, acquire the input information, or store the position information in a storage device such as a hard disk in advance. You may acquire position information. Furthermore, in addition to the position information of the radio wave transmission vehicle and the radio wave reception vehicle, the position information acquisition unit 11 of the present embodiment has information on the size and speed thereof, road information (road position, shape (straight line, curve, etc.), Information on parameters necessary for analysis (parameter information) such as information on the width (such as the width) and obstacle information (such as the position and size of the building) is acquired (the information may be two-dimensional information, 3D information may be used). Note that the parameter information may not be acquired by the position information acquisition unit 11. The radio wave propagation analysis apparatus may be provided with other functions for acquiring the information and acquired individually.

  The radio wave propagation analysis unit 12 has a function of performing radio wave propagation analysis between the radio wave transmitting vehicle and the radio wave receiving vehicle. Radio wave propagation analysis by the radio wave propagation analysis unit 12 is based on existing radio waves such as electromagnetic field analysis methods, geometrical optical analysis methods, and methods using statistical formulas (methods using the Okumura-Kashiwa curve, Sakagami formula, Ikegami formula, etc.). Any technique of propagation analysis may be applied (including techniques described in other patent documents).

In general, high-accuracy radio wave propagation analysis requires a large amount of computation and a long processing time. On the other hand, radio wave propagation analysis (simple radio wave propagation analysis) that can be performed in a short processing time requires a small amount of computation but has low analysis accuracy. For this reason, when performing high-accuracy radio wave propagation analysis, if there are multiple radio wave reception nodes, a very long processing time will be required. It will be lower.

  Therefore, the radio wave propagation analysis unit 12 of the present embodiment can select an analysis method used for radio wave propagation analysis from a plurality of analysis methods, and can make the radio wave propagation analysis analysis method different for each radio wave receiving vehicle. did. In order to make the analysis method different for each radio wave receiving vehicle, for example, an analysis algorithm, an analysis parameter, and the like may be made different. Specifically, high-accuracy analysis algorithms (or analysis parameters, etc.) may be used for radio wave receiving vehicles that require high-accuracy radio wave propagation analysis, and simple analysis algorithms ( Alternatively, analysis parameters or the like may be used. The analysis parameter is a parameter necessary for the analysis, for example, spatial resolution, temporal resolution, obstacle shape, etc. (In the case of using the ray launching method, the transmission angle interval of light rays is used as the analysis parameter. Also good).

  As a result (by making the analysis method different for each radio receiving vehicle), the processing time is different for each radio receiving vehicle, the calculation amount is different for each radio receiving vehicle, and the analysis accuracy is improved for each radio receiving vehicle. It is possible to make it different. The analysis method selection process (a method for making the analysis method different for each radio wave receiving vehicle) will be described in detail later.

  The result storage unit 13 is a storage device that stores the result output from the radio wave propagation analysis unit 12. As the storage device, any specific technique such as a nonvolatile memory or a hard disk may be applied. Note that the result of the radio wave propagation analysis includes a received electric field strength of radio waves, a radio wave path, radio wave delay information, and the like.

  As the display unit 14, any specific technique such as a liquid crystal display may be applied.

<Radio wave propagation analysis function>
The function and processing flow of the radio wave propagation analyzer will be described with reference to the flowchart of FIG.

  When the radio wave propagation analysis process is activated, the position information acquisition unit 11 acquires position information and parameter information (size and speed of the radio transmission vehicle and radio reception vehicle, road information, and information on the obstacle) (step S11). ). Note that the user can check the position information and parameter information on the display unit 14 as necessary.

  An example of position information in this embodiment is shown in FIG. The position information in FIG. 3 includes information on one radio wave transmission vehicle 31, 13 radio wave reception vehicles 32, 14 buildings 33, and two roads 34.

  Next, the radio wave propagation analyzing unit 12 performs a radio wave propagation analysis between the radio wave transmitting vehicle and the radio wave receiving vehicle (step S12). At that time, the radio wave propagation analysis unit 12 can change the analysis method of the radio wave propagation analysis for each radio wave receiving vehicle.

  Then, the result of step S12 is stored in the result storage unit 13 (step S13). The user can check the stored result on the display unit 14.

<Analysis method selection process>
As described above, the radio wave propagation analysis for each of a plurality of radio wave receiving vehicles requires a very long processing time when using a high-precision analysis method, and the processing time is shortened when using a simple analysis method, Analysis accuracy will deteriorate. However, actually, of the multiple electric wave receiving vehicles,
Radio reception vehicles that require high-accuracy radio wave propagation analysis are limited, and there is almost no case where a high-precision analysis method must be used for each of all radio wave reception vehicles. Therefore, in the present embodiment, efficient radio wave propagation analysis is performed while maintaining the target accuracy by changing the analysis technique for each radio wave receiving vehicle (analysis technique selection process).

  A specific example (analysis method selection processing 1 to 4) of the analysis method selection processing (one processing in step S12) will be described in detail with reference to the flowcharts of FIGS. In step S12, any of the analysis method selection processes 1 to 4 described below may be used, or a method combining them may be used. The analysis method selection processing method may be automatically selected by the radio wave propagation analysis device, or may be selected by the user according to the purpose.

<Analysis method selection process 1>
In analysis method selection processing 1, at least one of a plurality of radio wave receiving vehicles is specified, and analysis is performed between the specified radio wave receiving vehicle (specific radio wave receiving vehicle) and a radio wave receiving vehicle other than the specific radio wave receiving vehicle. Different methods. This processing method has a small number of special radio wave receiving vehicles (radio wave receiving vehicles that require highly accurate radio wave propagation analysis compared to other radio wave receiving vehicles, or radio wave receiving vehicles that are sufficient with simple radio wave propagation analysis). Effective when present.

  For example, the position information acquisition unit 11 may specify the specific radio wave receiving vehicle by requesting the user to input information for specifying the specific radio wave receiving vehicle and acquiring the information. The information may be specified by being stored in a storage device such as a hard disk and acquiring the information from the storage device (note that the position information acquisition unit 11 may not acquire the information. The propagation analyzer may be provided with other functions for acquiring the information.) The information for specifying the specific radio wave receiving vehicle may be any information as long as the specific radio wave receiving vehicle can be specified, such as the identifier of the specific radio wave receiving vehicle, the position, and the distance from the radio wave transmitting vehicle.

  The specific radio wave receiving vehicle may be specified by the radio wave propagation analysis device based on road information or the like.

  For example, in the case of a simulation of a traffic accident prevention system, a radio wave receiving vehicle in a positional relationship that is likely to cause a traffic accident with respect to a radio wave transmitting vehicle may be specified based on position information, parameter information, and the like. Specifically, when the radio wave transmitting vehicle is in the vicinity of the intersection, whether or not the radio wave receiving vehicle in the vicinity of the same intersection is in a positional relationship that is likely to cause a traffic accident is determined based on the speed of each other. Then, when it is determined that the vehicle is in a positional relationship that is likely to cause a traffic accident, the radio wave receiving vehicle may be a specific radio wave receiving vehicle.

  As another example, in a simulation assuming that the radio wave transmitting vehicle performs unicast communication or multicast communication, the radio wave receiving vehicle that is the communication partner vehicle may be the specific radio wave receiving vehicle.

  In the present embodiment, a highly accurate analysis method is used for a specific radio wave receiving vehicle, and a simple analysis method is used for other radio wave receiving vehicles.

  FIG. 8 is a diagram illustrating an example of an analysis target in the present embodiment (the same components are given the same reference numerals). The example of FIG. 8 shows a case where one of the plurality of radio wave receiving vehicles 82 is specified as the specific radio wave receiving vehicle 81.

  The flowchart in FIG. 4 shows a specific example of the analysis technique selection process 1.

First, the radio wave propagation analysis unit 12 selects one of a plurality of radio wave receiving vehicles (step S).
21).

  Then, the radio wave propagation analysis unit 12 determines whether or not the radio wave receiving vehicle selected in step S21 is a specific radio wave receiving vehicle (step S22). When the selected radio wave receiving vehicle is a specific radio wave receiving vehicle (step S22; YES), a highly accurate radio wave propagation analysis is performed on the radio wave receiving vehicle (step S23), and the process proceeds to step S25. If the selected radio wave receiving vehicle is not a specific radio wave receiving vehicle (step S22; NO), simple radio wave propagation analysis is performed on the radio wave receiving vehicle (step S24), and the process proceeds to step S25.

  In step S25, the radio wave propagation analysis unit 12 determines whether there is another radio wave receiving vehicle. When there is another radio wave receiving vehicle (step S25; YES), the radio wave receiving vehicle is selected (step S21), and steps S21 to S25 are repeated until there is no other radio wave receiving vehicle. When radio wave propagation analysis is performed on all radio wave receiving vehicles (step S25; NO), the analysis method selection process 1 is terminated.

  As described above, the radio wave propagation analysis in the present embodiment is performed by the radio wave propagation analysis for the specific radio wave receiving vehicle and the radio wave propagation analysis for the radio wave receiving vehicle other than the specific radio wave receiving vehicle by the method of the analysis method selection process 1. The radio wave propagation analysis method can be made different (in the example of FIG. 8, a high-precision analysis method is used only for the radio wave receiving vehicle 81, and the radio wave propagation vehicle 82 is simple for other radio wave receiving vehicles 82. Analytical methods are used). This makes it possible to perform radio wave propagation analysis more efficiently than using a highly accurate analysis method for all radio wave receiving vehicles and more accurate than using a simple analysis method for all radio wave receiving vehicles. .

<Analysis method selection process 2>
In the analysis method selection process 2, the analysis method of the radio wave propagation analysis is varied according to the distance between the radio wave transmitting vehicle and the radio wave receiving vehicle. When simulating a system for preventing traffic accidents such as a pre-crash safety system, the importance of analysis differs depending on the distance from the radio wave receiving vehicle. This processing method is effective in such a case. For example, a radio wave receiving vehicle that is closer to the radio wave transmission vehicle uses a more accurate analysis method, or a distance from the radio wave transmission vehicle is longer. It is possible to use a highly accurate analysis method for radio wave receiving vehicles, and to use a high accuracy analysis method when the distance from the radio wave transmitting vehicle is near a certain distance. The distance between the radio wave transmitting vehicle and the radio wave receiving vehicle may be a linear distance, or a route may be searched based on road information, and may be the distance of the searched route. It may vary depending on the direction.

  In the present embodiment, when the distance between the radio wave transmission vehicle and the radio wave reception vehicle is less than the distance La, the radio wave propagation analysis unit 12 uses a highly accurate analysis method, and the distance between the radio wave transmission vehicle and the radio wave reception vehicle is the distance La. As described above, the standard analysis method is used when the distance is less than the distance Lb, and information that the simple analysis method is used when the distance between the radio wave transmission vehicle and the radio wave reception vehicle is equal to or greater than the distance Lb is set in advance. Note that the information may be any information as long as the analysis method can be varied depending on the distance. For example, the analysis method may be determined by the value of a function that uses the distance as a variable. Further, the information may not be set in advance, but may be provided in the radio wave propagation analysis device with a function of acquiring the information, or may be acquired by the position information acquisition unit 11. In that case, the function may request the user to input the information, acquire the input information, or store the information in a storage device such as a hard disk in advance. You may get it.

  The flowchart in FIG. 5 shows a specific example of the analysis technique selection process 2.

First, the radio wave propagation analysis unit 12 selects one of a plurality of radio wave receiving vehicles (step S).
31).

  Next, the radio wave propagation analyzing unit 12 calculates the distance between the radio wave transmitting vehicle and the radio wave receiving vehicle selected in step S31 (step S32). FIG. 9 is a diagram illustrating an example of an analysis target in the present embodiment (the same components are given the same reference numerals). In the example of FIG. 9, among the plurality of radio wave receiving vehicles 32 in FIG. 3, the distance between each of the five radio wave receiving vehicles 91 and the radio wave transmitting vehicle 31 is less than the distance La, and each of the three radio wave receiving vehicles 92 is In this example, the distance to the radio wave transmission vehicle 31 is not less than the distance La and less than the distance Lb, and the distance between each of the five radio wave reception vehicles 93 and the radio wave transmission vehicle 31 is not less than the distance Lb.

  Then, the radio wave propagation analysis unit 12 selects a radio wave propagation analysis analysis method for the radio wave receiving vehicle according to the distance calculated in step S32 (step S33). In this embodiment, when the distance between the radio wave transmitting vehicle and the radio wave receiving vehicle <distance La, a highly accurate analysis method is selected (step S34), and distance La ≦ distance between the radio wave transmitting vehicle and the radio wave receiving vehicle <distance Lb. In this case, a standard analysis method is selected (step S35), and if the distance Lb ≦ the distance between the radio wave transmission vehicle and the radio wave reception vehicle, a simple analysis method is selected (step S36). In the example of FIG. 9, when the radio wave receiving vehicle 91 is selected in step S31, a highly accurate analysis method is selected, and when the radio wave receiving vehicle 92 is selected, a standard analysis method is selected and the radio wave receiving vehicle is selected. When 93 is selected, a simple analysis method is selected.

  Next, the radio wave propagation analysis unit 12 performs radio wave propagation analysis using the analysis method selected in step S33 (step S37).

  When the radio wave propagation analysis for the radio wave receiving vehicle selected in step S31 is completed (after step S37), the radio wave propagation analysis unit 12 determines whether there is another radio wave receiving vehicle (step S38). If there is another radio wave receiving vehicle (step S38; YES), the radio wave receiving vehicle is selected (step S31), and steps S31 to S38 are repeated until there is no other radio wave receiving vehicle. When radio wave propagation analysis is performed on all radio wave receiving vehicles (step S38; NO), the analysis method selection process 2 is terminated.

  As described above, the radio wave propagation analysis in the present embodiment can vary the radio wave propagation analysis analysis method according to the distance between the radio wave transmission vehicle and the radio wave reception vehicle by the method of the analysis method selection process 2. This makes it possible to perform radio wave propagation analysis more efficiently than using a highly accurate analysis method for all radio wave receiving vehicles and more accurate than using a simple analysis method for all radio wave receiving vehicles. .

  In this embodiment, three distance ranges are set and different analysis methods are set for each range. However, the number of distance ranges may be any number, and the same analysis method may be used for different ranges. May be set.

<Analysis method selection process 3>
In the analysis method selection processing 3, the analysis method is made different between the radio wave receiving vehicle in the partial area and the radio wave receiving vehicle outside the partial area (the partial area is a part of the area to be analyzed). In this embodiment, since radio wave propagation analysis between vehicles is taken as an example, the partial area is preferably a region including a road, or a part of a road. It is preferable to select based on road information or the like.) This processing method is effective when an analysis method used for radio wave propagation analysis is predetermined for each region.

FIG. 10 is a diagram illustrating an example of an analysis target in the present embodiment. In the present embodiment, FIG.
And the analysis method used for the radio wave receiving vehicle in the partial area (in this embodiment, a highly accurate analysis method is used for the partial area 101) and the radio wave receiving vehicle outside the partial area. It is assumed that information with an analysis method (simple analysis method in the present embodiment) is set in advance (the information is referred to as analysis information). The partial area information may be any information that can represent a partial area of the target area, such as the position of the apex of the partial area, the center position, and its radius. In the present embodiment, only one partial area is set, but the number of partial areas may be any number. In that case, the analysis method may be different for each partial area. For radio wave receiving vehicles outside the partial area, the analysis method may be different for each radio wave receiving vehicle regardless of the number of partial areas.

  Note that the analysis information is not set in advance, but the radio wave propagation analysis device may have a function of acquiring the information, or may be acquired by the position information acquisition unit 11. In that case, the function of acquiring the analysis information may request the user to input the information, acquire the input analysis information, or store the analysis information in a storage device such as a hard disk in advance. Or from the storage device.

  Note that the analysis information may be determined based on position information, parameter information, and the like by the radio wave propagation analysis apparatus instead of setting and acquisition. For example, in the case of a simulation of a traffic accident prevention system, a region where a radio wave transmitting vehicle is likely to encounter a traffic accident, a region where the possibility of encountering a traffic accident is low is detected based on position information, parameter information, etc. The region may be a partial area. Specifically, when the radio wave transmitting vehicle is near an intersection, it is determined based on position information, parameter information, and the like whether or not the vicinity of the intersection is likely to cause a traffic accident. Then, when it is determined that a traffic accident is likely to occur, an area near the intersection (such as an area having a certain extent with the center of the intersection as a central position) may be set as a partial area. In such cases, it is considered that high-precision analysis is necessary for areas that are likely to cause traffic accidents. Therefore, high-precision analysis methods are set for such partial areas. A simple analysis method may be set for the partial area (or the radio wave receiving vehicle that does not belong to the partial area).

  The example of FIG. 10 shows a case where among the plurality of radio wave receiving vehicles 32 in FIG. 3, six radio wave receiving vehicles 102 belong to the partial area 101 and seven radio wave receiving vehicles 103 do not belong to the partial area.

  The flowchart in FIG. 6 shows a specific example of the analysis technique selection process 3.

  First, the radio wave propagation analysis unit 12 selects one of a plurality of radio wave receiving vehicles (step S41).

  Then, the radio wave propagation analysis unit 12 determines which partial area the radio wave receiving vehicle selected in step S41 belongs (does not belong to the partial area), and selects an analysis method (step S42). In the present embodiment, when the radio wave receiving vehicle belongs to the partial area 101, a highly accurate analysis method is selected (step S43), and when it does not belong to the partial area, a simple analysis method is selected (step S44).

  Next, the radio wave propagation analysis unit 12 performs radio wave propagation analysis using the analysis method selected in step S42 (step S45).

When the radio wave propagation analysis for the radio wave receiving vehicle selected in step S41 is completed (after step S45), the radio wave propagation analysis unit 12 determines whether there is another radio wave receiving vehicle (step S46). If there is another radio wave receiving vehicle (step S46; YES), the radio wave receiving vehicle is selected (step S41), and steps S41 to S46 are repeated until there is no other radio wave receiving vehicle. When the radio wave propagation analysis is performed on all the radio wave receiving vehicles (step S46; NO), the analysis method selection process 3 ends.

  As described above, the radio wave propagation analysis in the present embodiment is based on the analysis method selection process 3 and considers a partial area, radio wave propagation analysis for a radio receiving vehicle in the partial area, and radio wave receiving vehicle outside the partial area. The radio wave propagation analysis method can be made different from the radio wave propagation analysis. This makes it possible to perform radio wave propagation analysis more efficiently than using a highly accurate analysis method for all radio wave receiving vehicles and more accurate than using a simple analysis method for all radio wave receiving vehicles. .

<Analysis method selection process 4>
In the analysis method selection processing 4, for each partial area, radio wave propagation analysis is performed only for the representative vehicle in that partial area. Then, the result of the radio wave propagation analysis is regarded as the result of the radio wave propagation analysis for each of all the radio wave receiving vehicles in the partial area. Thereby, the radio wave propagation analysis for the radio wave receiving vehicle other than the representative vehicle in the partial area can be omitted. Note that this processing method is used when a plurality of radio wave receiving vehicles exist at close distances and the analysis results are expected to be almost the same, or when the radio wave receiving vehicles have high accuracy radio waves. This is effective when propagation analysis is not required.

  The representative vehicle is, for example, one of the plurality of radio wave receiving vehicles 112 in the partial area 111 shown in FIG. 11 (representative vehicle 113 in FIG. 11). Further, a virtual radio wave receiving vehicle (representative vehicle 114 in FIG. 11) at the center position of a plurality of radio wave receiving vehicles in the partial area 111 may be used as the representative vehicle. Further, a virtual radio wave receiving vehicle (representative vehicle 115 in FIG. 11) at the center position of the partial area 111 or the like may be used as the representative vehicle.

  FIG. 12 is a diagram illustrating an example of an analysis target in the present embodiment. In this embodiment, it is assumed that the information of the partial area 121 and the partial area 122 shown in FIG. 12 is set in advance (in this embodiment, high-accuracy radio wave propagation analysis is required for radio wave receiving vehicles near intersections. And a partial area is provided at a position away from the intersection.) Although the analysis method is not described in detail in this embodiment, the same analysis method may be used for all radio wave propagation analysis, or may be different for each representative vehicle or for each radio wave receiving vehicle outside the partial area. .

  In the example of FIG. 12, among the plurality of radio wave receiving vehicles 32 in FIG. 3, four radio wave receiving vehicles 123 belong to the partial area 121, three radio wave receiving vehicles 124 belong to the partial area 122, and six radio wave receiving vehicles are received. The case where the vehicle 125 does not belong to a partial area is shown.

  The flowchart in FIG. 7 shows a specific example of the analysis technique selection process 4.

  First, the radio wave propagation analysis unit 12 selects one of a plurality of radio wave receiving vehicles (step S51).

Then, the radio wave propagation analyzing unit 12 determines whether or not the radio wave receiving vehicle selected in step S51 belongs to the partial area (step S52). If it is determined that it belongs to the partial area (step S52; YES), the representative vehicle of the partial area is determined (step S53), and the process proceeds to step S54. When it is determined that it does not belong to the partial area (step S52; NO), the process directly proceeds to step S54. In this embodiment, when the radio wave receiving vehicle 123 or the radio wave receiving vehicle 124 is selected in step S51, it is determined that the vehicle belongs to the partial area, and the representative vehicle 126 of the partial area 121 or the representative vehicle 127 of the partial area 122 shown in FIG. Is determined. When the radio wave receiving vehicle 125 is selected, it is determined that the vehicle does not belong to the partial area.

  In step S54, the radio wave propagation analysis unit 12 performs radio wave propagation analysis on the representative vehicle determined in step S53 or the radio wave reception vehicle that does not belong to the partial area selected in step S51.

  Next, the radio wave propagation analysis unit 12 determines whether or not the radio wave propagation analysis in step S54 is for the representative vehicle (step S55). If the radio wave propagation analysis is for the representative vehicle (step S55; YES), the process proceeds to step S56. If the radio wave propagation analysis is not for the representative vehicle (step S55; NO), the process proceeds to step S57. .

  In step S56, the radio wave propagation analyzing unit 12 sets the result of the radio wave propagation analysis for the representative vehicle obtained in step S54 as the result of the radio wave receiving vehicle in the partial area to which the representative vehicle belongs, and proceeds to step S57. At this time, the radio wave propagation analyzing unit 12 regards the radio wave receiving vehicle in the partial area to which the representative vehicle belongs as having been subjected to the radio wave propagation analysis, and excludes it from the processing target. In the present embodiment, the result of the representative vehicle 126 becomes the result of the radio wave receiving vehicle 123, and the result of the representative vehicle 127 becomes the result of the radio wave receiving vehicle 124.

  In step S57, the radio wave propagation analysis unit 12 determines whether there is another radio wave receiving vehicle. If there is another radio wave receiving vehicle (step S57; YES), the radio wave receiving vehicle is selected (step S51), and steps S51 to S57 are repeated until there are no other radio wave receiving vehicles. When radio wave propagation analysis has been performed for all radio wave receiving vehicles (step S57; NO), the analysis method selection process 4 ends.

  As described above, the radio wave propagation analysis in the present embodiment is performed by analyzing the radio wave propagation only for the representative vehicle in the partial area by using the method of the analysis method selection process 4. The result is the result of radio wave propagation analysis for each of all radio wave receiving vehicles in the partial area. This makes it possible to perform radio wave propagation analysis more efficiently than using a highly accurate analysis method for all radio wave receiving vehicles and more accurate than using a simple analysis method for all radio wave receiving vehicles. .

  In addition, although the said four methods were demonstrated as an analysis method selection process, it is not restricted to these, What kind of method may be used if it is a method which makes an analysis method different for every electromagnetic wave receiving vehicle.

  In this embodiment, the format of the position information is not described. However, the position information is image data, character data, numerical data, or the like as long as the position information of the radio wave receiving vehicle and the radio wave transmission vehicle can be acquired. Any format may be used. The user can change the contents of the position information while confirming the position information on the display unit 14.

  In the present embodiment, a building is considered as an obstacle. However, the present invention is not limited to a building, and may be anything as long as it reflects, transmits, and absorbs radio waves. For example, a radio wave transmitting vehicle and a radio wave receiving vehicle can also be obstacles.

  In the present embodiment, the partial area in the analysis method selection unit 3 and the analysis method selection unit 4 is not described in detail. However, if the partial area can be considered as a region, any size, shape, position, etc. It may be something like this. For example, the area of the partial area may be increased according to the distance from the radio wave transmitting vehicle, or a region surrounded by a polygon such as a triangle or a quadrangle, a circle or an ellipse may be used as the partial area. An annular region may be considered.

FIG. 1 is a block diagram showing a functional configuration of the radio wave propagation analyzing apparatus. FIG. 2 is a flowchart showing the flow of processing of the radio wave propagation analyzer. FIG. 3 is a diagram illustrating an example of position information. FIG. 4 is a flowchart showing the flow of the analysis technique selection process 1. FIG. 5 is a flowchart showing the flow of the analysis technique selection process 2. FIG. 6 is a flowchart showing the flow of the analysis technique selection process 3. FIG. 7 is a flowchart showing the flow of the analysis technique selection process 4. FIG. 8 is a diagram illustrating an example of an analysis target in the analysis technique selection process 1. FIG. 9 is a diagram illustrating an example of an analysis target in the analysis technique selection process 2. FIG. 10 is a diagram illustrating an example of an analysis target in the analysis technique selection process 3. FIG. 11 is a diagram illustrating an example of a representative vehicle. FIG. 12 is a diagram illustrating an example of an analysis target in the analysis technique selection process 4.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Position information acquisition part 12 Radio wave propagation analysis part 13 Result storage part 14 Display part 31 Radio wave transmission vehicle 32 Radio wave reception vehicle 33 Building 81 Specific radio wave reception vehicle 82 Radio wave reception vehicle 91,92,93 Radio wave reception vehicle 101 Partial area 102,103 Radio wave receiving vehicle 111 Partial area 112 Radio wave receiving vehicle 113, 114, 115 Representative vehicle 121, 122 Partial area 123, 124, 125 Radio wave receiving vehicle 126, 127 Representative vehicle

Claims (9)

A radio wave propagation analysis device that performs radio wave propagation analysis between a radio wave transmission node and a plurality of radio wave reception nodes,
Position information acquisition means for acquiring position information of a radio wave transmission node and a plurality of radio wave reception nodes;
Radio wave propagation analysis means for performing radio wave propagation analysis between the radio wave transmission node and the radio wave reception node;
With
The radio wave propagation analysis means can select an analysis method used for radio wave propagation analysis from a plurality of analysis methods, and the radio wave propagation analysis method can be made different for each radio wave receiving node. Radio wave propagation analyzer. The radio wave propagation analysis means makes the radio wave propagation analysis analysis method different between a specific radio wave reception node specified from the plurality of radio wave reception nodes and a radio wave reception node other than the specific radio wave reception node. The radio wave propagation analysis apparatus according to claim 1. 3. The radio wave propagation analysis unit changes an analysis method of the radio wave propagation analysis according to a distance between the radio wave transmission node and the radio wave reception node. 4. The described radio wave propagation analyzer.   The radio wave propagation analysis means is characterized in that the radio wave propagation analysis method is made different between a radio wave receiving node in a partial area which is a part of an analysis target area and a radio wave receiving node outside the partial area. The radio wave propagation analyzer according to any one of claims 1 to 3. The radio wave propagation analyzing means performs a radio wave propagation analysis only for a representative node of the partial area for each partial area that is a part of the analysis target area, and the result of the radio wave propagation analysis is performed on all the areas in the partial area. The radio wave propagation analysis apparatus according to any one of claims 1 to 4, wherein the radio wave propagation analysis apparatus is regarded as a result of radio wave propagation analysis for each of the radio wave reception nodes. The radio wave propagation analysis apparatus according to any one of claims 1 to 5, wherein the plurality of analysis methods have different analysis algorithms. The radio wave propagation analysis apparatus according to claim 1, wherein the plurality of analysis methods have different analysis parameters. Computer
Obtaining position information of a radio wave transmission node and a plurality of radio wave reception nodes;
Performing radio wave propagation analysis between the radio wave transmission node and the radio wave reception node;
A radio wave propagation analysis method for performing
In the step of performing the radio wave propagation analysis,
A radio wave propagation analysis method that can select an analysis method to be used for radio wave propagation analysis from a plurality of analysis methods, and can vary the radio wave propagation analysis method for each radio wave receiving node. On the computer,
Obtaining position information of a radio wave transmission node and a plurality of radio wave reception nodes;
Performing radio wave propagation analysis between the radio wave transmission node and the radio wave reception node;
A radio wave propagation analysis program for executing
In the step of performing the radio wave propagation analysis,
A radio wave propagation analysis program that can select an analysis method to be used for radio wave propagation analysis from a plurality of analysis methods and can vary the radio wave propagation analysis method for each radio wave receiving node.

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