JP5592927B2 - Propagation characteristic estimation device, propagation characteristic estimation method, and propagation characteristic estimation program - Google Patents

Description

  The present invention relates to a propagation characteristic estimation device, a propagation characteristic estimation method, and a propagation characteristic estimation program in a wireless communication system.

  Propagation loss estimation methods in wireless communication systems are roughly classified into two types: site specific and site general. Site-specific estimation is an estimation method that enables estimation of propagation loss specific to a specific location. On the other hand, site general estimation is an estimation method for estimating a general tendency of propagation characteristics that is not unique to a place.

  ITU-R recommendation P.I. 1812 (Non-Patent Document 1) uses a propagation characteristic estimation method that enables site-specific estimation, and mainly uses topographic information and land use distribution issued by the Geospatial Information Authority of Japan to determine the effect of surrounding buildings as clutter height. Propagation loss is estimated by taking this into consideration. This estimation method uses topographic information and land use distribution information.

  Here, with reference to FIG. 8, the structure of the propagation characteristic estimation apparatus which performs propagation characteristic estimation by a prior art is demonstrated. FIG. 8 is a block diagram showing a configuration of a propagation characteristic estimation apparatus that performs propagation characteristic estimation according to the prior art. In FIG. 4, reference numeral 1 is a terrain database (DB) in which terrain information is stored in advance. Reference numeral 2 denotes a land use distribution database (DB) in which land use distribution information is stored in advance. Reference numeral 3 denotes a calculation result storage unit that stores a result (estimation result) of calculating propagation characteristics. Reference numeral 4 denotes a parameter input unit for setting parameters necessary for estimating propagation characteristics. Reference numeral 5 denotes an array initialization unit that initializes an array used for calculation for estimating propagation characteristics.

  Reference numeral 6 denotes a line-of-sight propagation loss calculation unit that calculates line-of-sight propagation loss. Reference numeral 7 denotes a diffraction loss calculation unit for calculating a loss due to diffraction. Reference numeral 8 denotes an atmospheric scattering calculation unit for calculating the influence of scattering by the atmosphere. Reference numeral 9 denotes a singular propagation calculation unit for calculating the influence of singular propagation. Reference numeral 10 denotes an additional loss calculation unit for the surrounding building that calculates the additional loss due to the surrounding building. Reference numeral 11 denotes a place rate calculation unit for calculating the place rate. Reference numeral 12 denotes a building intrusion loss calculation unit for calculating the building intrusion loss.

  Next, the processing operation of the propagation characteristic estimation apparatus shown in FIG. 8 will be described with reference to FIG. FIG. 9 is a flowchart showing the processing operation of the propagation characteristic estimation apparatus shown in FIG. First, the parameter input unit 4 inputs parameters (frequency, transmission / reception point position, etc.) necessary for propagation characteristic estimation (step S11). The array initialization unit 5 initializes the array used for calculation of propagation characteristic estimation, and calculates each calculation unit (line-of-sight propagation loss calculation unit 6, diffraction loss calculation unit 7, atmospheric scattering calculation unit 8, singular propagation calculation unit 9 The additional loss calculation unit 10 by the surrounding building, the location rate calculation unit 11 and the building intrusion loss calculation unit 12) read data from the terrain DB1 and the land use DB2 (step S12), and create a profile obtained by adding clutter height to the terrain. (Step S13).

  Next, the line-of-sight propagation loss calculation unit 6 calculates an estimated value of line-of-sight propagation loss (step S14). Next, the diffraction loss calculator 7 calculates an estimated value of diffraction loss (step S15). Subsequently, the atmospheric scattering calculation unit 8 calculates an estimated value of the influence of atmospheric scattering (step S16).

  Next, the singular propagation calculation unit 9 calculates an estimated value of the influence of singular propagation such as a duct (step S17). Subsequently, the additional loss calculation unit 10 due to the surrounding building calculates an estimated value of the additional loss due to the surrounding building (step S18). Next, the location rate calculation unit 11 calculates the location rate (step S19). Finally, the building penetration loss calculation unit 12 calculates an estimated value of the building penetration loss (step S20). And each calculation part (line-of-sight propagation loss calculation part 6, diffraction loss calculation part 7, atmospheric scattering calculation part 8, singular propagation calculation part 9, additional loss calculation part 10 by surrounding buildings, place rate calculation part 11, building penetration loss The estimated value in the calculation unit 12) is added to obtain the propagation characteristic estimated value.

  Here, a specific calculation method for the diffraction loss estimation process (step S15) shown in FIG. 9 will be described with reference to FIG. FIG. 6 is a diagram showing a specific calculation method for the diffraction loss estimation process (step S15) shown in FIG. In the diffraction loss estimation process, as shown in FIG. In 1812, a model in which a maximum of three diffraction points existing between transmission and reception are set based on the structure of the topography is used, and the height of each point is related to the clutter type and the clutter height according to the land use distribution information. Add the recommended clutter heights obtained with reference to, and add each diffraction loss.

Rec. ITU-R P.1812: "A path-specific propagation prediction method for point-to-area terrestrial services in the VHF and UHF bands," ITU-R Recommendations, Volume 2012 P Series-Part 2, ITU, Geneva.

  ITU-R recommendation P.I. Although 1812 advocates site-specific estimation methods, there are many areas where it is difficult to obtain building information such as the shape, location, and height information of buildings when viewed globally, so the effects of buildings, vegetation, etc. In the diffraction loss estimation, site general modeling is performed as the clutter height, and loss estimation is performed based on the modeled value.

  However, this clutter height is only a recommended value, and it is necessary to change the clutter height according to the actual building situation, and it is difficult to set an appropriate clutter height from the actual building situation. There is a problem that it is difficult to improve the accuracy of the estimated value.

  On the other hand, in Japan in recent years, an environment in which building information such as building shape, location, and height information can be used as a database has been developed. By using this database, values such as average building height can be calculated, but it is clear that clutter height is different from average building height and how clutter height is statistically calculated from the building database. Since there is no definition, there is also a problem that it is difficult to estimate the additional loss due to surrounding buildings using an appropriate clutter height.

  The present invention has been made in view of such circumstances, and provides a propagation characteristic estimation device, a propagation characteristic estimation method, and a propagation characteristic estimation program capable of improving the calculation accuracy of a propagation characteristic estimation value in a wireless communication system. With the goal.

  The present invention is a propagation characteristic estimation apparatus for estimating propagation characteristics in a wireless communication system, and includes a terrain database in which terrain data is stored in advance, a building database in which building data is stored in advance, and land use distribution data in advance. Land use distribution database, the topographic data stored in the topographic database, the building data stored in the building database, and clutter height data based on the land use distribution data stored in the land use distribution database The profile height is added to the position of the building between the transmission / reception points, and a profile with a predetermined clutter height added to the building position is added to the profile position. , Diffraction loss calculation means for calculating diffraction loss, and propagation loss within line of sight Based on the line-of-sight propagation loss calculation means for calculating, the surrounding building additional loss calculation means for calculating the additional loss due to the surrounding building, the diffraction loss, the line-of-sight propagation loss, and the additional loss due to the surrounding building, Propagation characteristic estimating means for calculating an estimated value of the propagation characteristic is provided.

  In order to estimate propagation characteristics in a wireless communication system, the present invention provides a terrain database in which terrain data is stored in advance, a building database in which building data is stored in advance, and a land use distribution in which land use distribution data is stored in advance. A propagation characteristic estimation method performed by a propagation characteristic estimation apparatus comprising a database, wherein the terrain data stored in the terrain database, the building data stored in the building database, and stored in a land use distribution database In addition, referring to the clutter height data based on the land use distribution data, the height of the building is added to the position of the building between the transmission and reception points, and the profile is added to the clutter height data in addition to the position of the building. Referring to the profile creation step A diffraction loss calculation step, a line-of-sight propagation loss calculation step for calculating line-of-sight propagation loss, a surrounding building additional loss calculation step for calculating additional loss due to surrounding buildings, the diffraction loss, and the line-of-sight propagation loss And a propagation characteristic estimation step of calculating an estimated value of the propagation characteristic based on the additional loss due to the surrounding building.

  The present invention is a propagation characteristic estimation program for causing a computer to function as the propagation characteristic estimation apparatus.

  According to the present invention, it is possible to improve the calculation accuracy of the propagation characteristic estimation value.

It is a block diagram which shows the structure of one Embodiment of this invention. It is a flowchart which shows the processing operation of the propagation characteristic estimation apparatus shown in FIG. It is a figure which shows the specific calculation method about the diffraction loss estimation process (step S5) shown in FIG. It is the figure which compared the calculation method of "diffraction loss estimation" in a prior art and this invention. It is a figure which shows the method of calculating the additional loss by the surrounding building shown in FIG. It is a figure which shows the difference in the calculation method of the propagation characteristic when not using it, when using the data of building DB13. It is a figure which shows the result of having compared the measurement result, the propagation characteristic estimation result by this invention, and the propagation characteristic estimation result by a prior art. It is a block diagram which shows the structure of the propagation characteristic estimation apparatus which performs the propagation characteristic estimation by a prior art. It is a flowchart which shows the processing operation of the propagation characteristic estimation apparatus shown in FIG. It is explanatory drawing which shows the specific calculation method about the diffraction loss estimation process (step S15) shown in FIG.

  Hereinafter, a propagation characteristic estimation apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the embodiment. In this figure, the same parts as those in the conventional apparatus shown in FIG. The apparatus shown in this figure is different from the conventional apparatus in that a building database (DB) 13 in which building data is stored in advance is newly provided.

  Next, the processing operation of the propagation characteristic estimation apparatus shown in FIG. 1 will be described with reference to FIG. FIG. 2 is a flowchart showing the processing operation of the propagation characteristic estimation apparatus shown in FIG. First, the parameter input unit 4 inputs parameters (frequency, transmission / reception point position, etc.) necessary for propagation characteristic estimation (step S1). Then, the array initialization unit 5 initializes the array used for calculation of propagation characteristic estimation. Subsequently, each calculation unit (line-of-sight propagation loss calculation unit 6, diffraction loss calculation unit 7, atmospheric scattering calculation unit 8, singular propagation calculation unit 9, additional loss calculation unit 10 by surrounding buildings, place rate calculation unit 11, building intrusion The loss calculation unit 12) reads data from the terrain DB1, the land use DB2, and the building DB 13 (step S2), and creates a profile based on the building, terrain, and clutter height (step S3).

  Next, the line-of-sight propagation loss calculation unit 6 calculates an estimated value of line-of-sight propagation loss (step S4). Next, the diffraction loss calculator 7 calculates an estimated value of the diffraction loss (step S5). Subsequently, the atmospheric scattering calculation unit 8 calculates an estimated value of the influence of atmospheric scattering (step S6).

  Next, the singular propagation calculation unit 9 calculates an estimated value of the influence of singular propagation such as a duct (step S7). Subsequently, the additional loss calculation unit 10 due to the surrounding building calculates an estimated value of the additional loss due to the surrounding building (step S8). Next, the location rate calculation unit 11 calculates the location rate (step S9). Finally, the building penetration loss calculation unit 12 calculates an estimated value of the building penetration loss (step S10). And each calculation part (line-of-sight propagation loss calculation part 6, diffraction loss calculation part 7, atmospheric scattering calculation part 8, singular propagation calculation part 9, additional loss calculation part 10 by surrounding buildings, place rate calculation part 11, building penetration loss The estimated value in the calculation unit 12) is added to obtain the estimated propagation characteristic value and stored in the calculation result storage unit 3.

  In the above description, the configuration for estimating line-of-sight propagation loss, diffraction loss, atmospheric scattering effects, singular propagation, location rate, and building entry loss has been described. And it is good also as an estimated value of a propagation characteristic by calculating only a diffraction loss and the additional loss by a surrounding building.

  Now, with reference to FIG. 3, a specific calculation method for the diffraction loss estimation process (step S5) shown in FIG. 2 will be described. FIG. 3 is a diagram showing a specific calculation method for the diffraction loss estimation process (step S5) shown in FIG. The diffraction loss estimation process is performed using a profile obtained from the terrain DB1, the building DB13, and the recommended clutter height. That is, in the diffraction loss estimation process, as shown in FIG. 3, a maximum of three diffraction points are set using a profile reflecting the building DB 13, the topography DB1, and the clutter height, and each diffraction loss is added.

  FIG. 4 is a diagram comparing the calculation method of “diffraction loss estimation” in the prior art and the present invention. As shown in FIG. 4, in the conventional method, a profile created by referring to a table in which the clutter type and the representative value of the clutter height are related is used for the calculation of the propagation characteristics. In order to improve the accuracy, it is necessary to change to a value of the clutter height suitable for the location.

  On the other hand, in the method according to the present invention, by referring to the data stored in the building DB 13, as shown in FIG. 4, the building DB 13, the terrain DB 1, and the profile reflecting the clutter height are used up to 3 Since the diffraction points of the points are set and the respective diffraction losses are added, the estimation accuracy can be improved. In particular, in the method according to the present invention, the calculation formula of diffraction loss is the same as that of the conventional method, but the profile required for the calculation is created in consideration of the building, terrain, and clutter height, so that the propagation characteristics The accuracy of the estimated value can be improved.

Next, a method for calculating the additional loss due to the surrounding building shown in FIG. 2 will be described with reference to FIG. FIG. 5 is a diagram illustrating a method of calculating the additional loss due to the surrounding building illustrated in FIG. The additional loss Ah is calculated by the equation (1). Since the equation (1) is a known calculation equation, detailed description thereof is omitted.

  In order to calculate the equation (1), the necessary parameters are defined as shown in FIG. The clutter height R is not the actual height of the building stored in the building DB 13, but a representative value in a table in which the clutter type shown in FIG. 5 is associated with the representative value of the clutter height R. As for the distance between the building and the transmission / reception point, a fixed representative value (27 m) is used instead of the actual distance stored in the building DB 13.

  FIG. 6 is a diagram illustrating a difference in calculation method of propagation characteristics between the case where the data of the building DB 13 is used and the case where the data is not used in the mountainous area and the plain area. As shown in FIG. 6, by using a profile based on data stored in the actual building DB 13, it is possible to estimate the propagation loss without calculating an appropriate clutter height. In large cities, the recommended clutter height is as low as 20m, so it is more accurate without using the data stored in the building DB13 to calculate the appropriate clutter height as described above. High estimation is possible.

  In this way, by using the data stored in the terrain DB 1 and the building DB 13 and performing the propagation loss estimation based on the profile close to the actual state, the propagation loss estimation accuracy is conventionally improved without calculating an appropriate clutter height. It becomes possible to improve from the law.

  Next, with reference to FIG. 7, the result of comparing the measurement result of the propagation characteristic, the propagation characteristic estimation result according to the present invention, and the propagation characteristic estimation result according to the prior art will be described. FIG. 7 is a diagram illustrating a result of comparing the propagation characteristic measurement result, the propagation characteristic estimation result according to the present invention, and the propagation characteristic estimation result according to the prior art. As shown in FIG. 7, the propagation characteristic estimation result according to the present invention is closer to the measured value than the propagation characteristic estimation result according to the conventional method.

  As described above, when calculating the diffraction loss in the propagation characteristic estimation method for calculating the propagation characteristic by calculating the line-of-sight propagation loss, the diffraction loss, and the additional loss due to surrounding buildings, and adding these losses, As a profile to be used for the terrain profile, add the height of the building to the position of the building between the transmission and reception points in the terrain profile (excluding the surroundings of the transmission and reception point), and add the specified clutter height to the position of the building. Created and used. This differs in that the building is taken into account when creating the profile compared to the prior art.

  With this configuration, it is possible to improve the estimation accuracy of the propagation loss as compared with the prior art. In large cities, the influence of surrounding buildings is so great that the estimation accuracy is improved by taking into account the influence of surrounding buildings, while in small and medium cities, the influence of surrounding buildings is not so great. If the influence is taken into account, the loss is overestimated, and the estimation accuracy tends to deteriorate instead. The propagation characteristic estimation method described above is mainly suitable for a propagation characteristic estimation method for large cities.

  The program for realizing the function of the processing unit in FIG. 1 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into the computer system and executed to execute propagation characteristic estimation processing. May be performed. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer system” includes a WWW system having a homepage providing environment (or display environment). The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Further, the “computer-readable recording medium” refers to a volatile memory (RAM) in a computer system that becomes a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. In addition, those holding programs for a certain period of time are also included.

  The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, what is called a difference file (difference program) may be sufficient.

  As mentioned above, although embodiment of this invention has been described with reference to drawings, the said embodiment is only the illustration of this invention, and it is clear that this invention is not limited to the said embodiment. is there. Accordingly, additions, omissions, substitutions, and other changes of the components may be made without departing from the technical idea and scope of the present invention.

  The present invention can be applied to uses where it is essential to improve the calculation accuracy of propagation characteristic estimation values in a wireless communication system.

  DESCRIPTION OF SYMBOLS 1 ... Topography DB, 3 ... Calculation result memory | storage part, 4 ... Parameter input part, 5 ... Array initialization part, 6 ... Line-of-sight propagation loss calculation part, 7 ... Diffraction loss Calculation part, 8 ... Atmospheric scattering calculation part, 9 ... Singular propagation calculation part, 10 ... Location rate calculation part, 12 ... Building penetration loss calculation part, 13 ... Building DB

Claims (3)

A propagation characteristic estimation device for estimating propagation characteristics in a wireless communication system,
A terrain database in which terrain data is stored in advance;
A building database pre-stored with building data;
A land use distribution database in which land use distribution data is stored in advance;
Said terrain data between the transmitting and receiving points of interest to estimate the terrain database stored the propagation characteristics, the said building data between buildings the transceiver point stored in the database, the stored land usage distribution database Referring to clutter height data based on the land use distribution data between the transmitting and receiving points, as well as additional building height, respectively the position of the building on the terrain between the transmitting and receiving points, predetermined clutter height in addition to the position of the building Profile creation means for creating a profile with each added,
Diffraction loss calculating means for calculating a diffraction loss between the transmitting and receiving points with reference to the profile;
Line-of- sight propagation loss calculation means for calculating line-of-sight propagation loss between the transmission and reception points ;
Surrounding building additional loss calculating means for calculating additional loss due to surrounding buildings between the transmission and reception points ;
And the diffraction loss, and propagation loss in the sight, based on the additional losses due to the ambient building, the propagation characteristic estimation apparatus being characterized in that a propagation characteristic estimation means for calculating an estimated value of the propagation characteristics . In order to estimate propagation characteristics in a wireless communication system, a terrain database in which terrain data is stored in advance, a building database in which building data is stored in advance, and a land use distribution database in which land use distribution data is stored in advance are provided. A propagation characteristic estimation method performed by the propagation characteristic estimation apparatus,
Said terrain data between the transmitting and receiving points of interest to estimate the terrain database stored the propagation characteristics, the said building data between buildings the transceiver point stored in the database, the stored land usage distribution database Referring to clutter height data based on the land use distribution data between the transmitting and receiving points, as well as additional building height, respectively the position of the building on the terrain between the transmitting and receiving point, the clutter height data in addition to the position of the building A profile creation step for creating a profile with each added,
A diffraction loss calculation step of calculating a diffraction loss between the transmission and reception points with reference to the profile;
Line-of- sight propagation loss calculation step for calculating line-of-sight propagation loss between the transmission and reception points ;
Surrounding building additional loss calculation step for calculating additional loss due to surrounding buildings between the transmission and reception points ;
And the diffraction loss, and propagation loss in the sight, based on the additional losses due to the ambient buildings, propagation characteristic estimation method characterized by having a propagation characteristic estimating step of calculating an estimated value of the propagation characteristics.   A propagation characteristic estimation program for causing a computer to function as the propagation characteristic estimation apparatus according to claim 1.

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