WO2021261031A1 - Système de prédiction de propagations, procédé de prédiction de propagations et support d'enregistrement stockant un programme de prédiction de propagations - Google Patents

Système de prédiction de propagations, procédé de prédiction de propagations et support d'enregistrement stockant un programme de prédiction de propagations Download PDF

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Publication number
WO2021261031A1
WO2021261031A1 PCT/JP2021/010539 JP2021010539W WO2021261031A1 WO 2021261031 A1 WO2021261031 A1 WO 2021261031A1 JP 2021010539 W JP2021010539 W JP 2021010539W WO 2021261031 A1 WO2021261031 A1 WO 2021261031A1
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Prior art keywords
clutter
dominant
base station
loss
propagation
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PCT/JP2021/010539
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English (en)
Japanese (ja)
Inventor
威生 藤井
直 宮本
啓太 片桐
宏一 安達
光哉 佐藤
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国立大学法人電気通信大学
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Priority claimed from JP2020170283A external-priority patent/JP2022007866A/ja
Application filed by 国立大学法人電気通信大学 filed Critical 国立大学法人電気通信大学
Publication of WO2021261031A1 publication Critical patent/WO2021261031A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B17/00—Monitoring; Testing
    • H04B17/30—Monitoring; Testing of propagation channels
    • H04B17/373—Predicting channel quality or other radio frequency [RF] parameters
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/14—Spectrum sharing arrangements between different networks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
    • H04W16/18—Network planning tools
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W24/00—Supervisory, monitoring or testing arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W24/00—Supervisory, monitoring or testing arrangements
    • H04W24/06—Testing, supervising or monitoring using simulated traffic

Definitions

  • the present invention relates to a propagation prediction system, a propagation prediction method, and a recording medium containing a propagation prediction program, and in particular, a propagation prediction system for predicting propagation loss between base stations of two wireless communication systems using the same frequency, propagation. It can be suitably used as a recording medium in which a prediction method and a propagation prediction program are stored.
  • the frequency band used in wireless communication is finite, and with the spread of mobile terminals that perform wireless communication, there is a demand for a method of using the frequency band more efficiently. From this point of view, a technique for allocating the same frequency band to a plurality of wireless communication systems is being studied.
  • control is performed to stop at least a part of the lower priority secondary radio communication system using the same frequency at the time and region where the higher priority primary radio communication system performs wireless communication. Can be considered.
  • This control may be performed by predicting the interference power to the primary base station included in the primary wireless communication system for each of the secondary base stations included in the secondary wireless communication system. This interference power may be predicted based on the propagation loss between the primary base station and the secondary base station.
  • wireless communication systems with higher priority include wireless relay transmission systems for television broadcasting and wireless communication systems related to disaster prevention or defense.
  • wireless communication system having a lower priority wireless communication using a mobile phone, a smartphone, or the like, particularly wireless communication by carrier aggregation that bundles and uses a plurality of frequency bands can be mentioned.
  • Non-Patent Document 1 (ITU-R (Radiocommunication Sector of International Telecommunication Union), "Recommunication ITU-R P.2108-0 (06/2017) Redocommunication Section ], June 20, 2017, Internet ⁇ URL: https://www.itu.int/dms_pubrec/itu-r/rec/p/R-REC-P.2108-0-201706-I ! PDF- E.pdf>) discloses a calculation method for modeling the propagation environment of electromagnetic waves and approximately predicting the propagation loss due to clutter existing in this propagation environment.
  • Non-Patent Document 1 the elevation difference of the transmitting side antenna, the receiving side antenna, the clutter, etc. is not taken into consideration, and the propagation predicted when there is a clutter such as a building significantly higher than the antenna. The loss error increases.
  • the propagation prediction system includes an arithmetic unit and an input / output unit.
  • the arithmetic unit estimates the propagation path between the primary base station and the secondary base station, and predicts the propagation loss in the propagation path.
  • the input / output device outputs an output signal according to the propagation loss.
  • the arithmetic unit is the first dominant clutter that has the maximum elevation angle when the apex of the clutter is seen from the primary base station, and the clutter from the secondary base station. Select the second dominant clutter that has the maximum elevation angle when looking at the apex of.
  • the arithmetic unit is the distance from the primary base station to the first dominant clutter, the distance from the first dominant clutter to the second dominant clutter, the distance from the second dominant clutter to the secondary base station, and the primary base. Based on the respective altitudes of the station, the first dominant clutter, the second dominant clutter, and the secondary base station, the component of the propagation loss caused by the first dominant clutter and the second dominant clutter is calculated as the clutter loss. do.
  • the arithmetic unit predicts the propagation loss by approximating the component of the propagation loss excluding the clutter loss to the free space loss.
  • the propagation prediction method estimates the propagation path between the primary base station and the secondary base station, predicts the propagation loss of the propagation path, and outputs an output signal according to the propagation loss. Including that. Predicting propagation loss is to select the first dominant clutter that has the maximum elevation angle from the primary base station to the apex of the clutter from the clutters located between the primary base station and the secondary base station. This includes selecting the second dominant clutter that has the maximum elevation angle when the apex of the clutter is seen from the secondary base station from the clutters arranged between the primary base station and the secondary base station.
  • Predicting propagation loss also means the distance from the primary base station to the first dominant clutter, the distance from the first dominant clutter to the second dominant clutter, and the distance from the second dominant clutter to the secondary base station. Due to the first dominant clutter and the second dominant clutter of the propagation loss, based on the distance of the primary base station, the first dominant clutter, the second dominant clutter, and the respective altitudes of the secondary base stations. Includes calculating the component as a clutter loss. Predicting the propagation loss further includes approximating the components of the propagation loss excluding the clutter loss to the free space loss.
  • the recording medium in which the propagation prediction program is stored is a recording medium in which the program for realizing a predetermined function in the computer is stored.
  • a predetermined function includes estimating the propagation path between the primary base station and the secondary base station, predicting the propagation loss of the propagation path, and outputting an output signal according to the propagation loss.
  • Predicting propagation loss is to select the first dominant clutter that has the maximum elevation angle from the primary base station to the apex of the clutter from the clutters located between the primary base station and the secondary base station. This includes selecting the second dominant clutter that has the maximum elevation angle when the apex of the clutter is seen from the secondary base station from the clutters arranged between the primary base station and the secondary base station.
  • Predicting propagation loss also means the distance from the primary base station to the first dominant clutter, the distance from the first dominant clutter to the second dominant clutter, and the distance from the second dominant clutter to the secondary base station.
  • the component of the propagation loss due to the 1st dominant clutter and the 2nd dominant clutter based on the distance of the primary base station, the 1st dominant clutter, the 2nd dominant clutter and the secondary base station respectively. Includes calculating as a clutter loss. Predicting the propagation loss further includes approximating the components of the propagation loss excluding the clutter loss to the free space loss.
  • FIG. 1 is a diagram showing a configuration example of a propagation prediction system according to an embodiment.
  • FIG. 2A is a block circuit diagram showing a configuration example of a server of a propagation prediction system according to an embodiment.
  • FIG. 2B is a block circuit diagram showing an example of the configuration of the server shown in FIG. 2A from a functional point of view.
  • FIG. 3 is a flowchart showing a configuration example of a propagation prediction method according to an embodiment.
  • FIG. 4 is a diagram for explaining a method of selecting a dominant clutter in one embodiment.
  • FIG. 5 is a diagram for explaining parameters derived from the positional relationship between the antenna and the dominant clutter according to the embodiment.
  • FIG. 1 is a diagram showing a configuration example of a propagation prediction system according to an embodiment.
  • FIG. 2A is a block circuit diagram showing a configuration example of a server of a propagation prediction system according to an embodiment.
  • FIG. 2B is a block circuit diagram showing an example of the configuration of the
  • FIG. 6 is a diagram for explaining a case where the dominant clutter corresponding to the two antennas is the same in one embodiment.
  • FIG. 7 is a flowchart showing a modified example of the propagation prediction method according to the embodiment.
  • FIG. 8A is a flowchart showing another modification of the propagation prediction method according to the embodiment.
  • FIG. 8B is a flowchart showing still another modification of the propagation prediction method according to the embodiment.
  • FIG. 8C is a flowchart showing a modified example of the propagation prediction method according to the embodiment.
  • FIG. 9 is a diagram for explaining parameters derived from the positional relationship between two antennas having different altitudes and a dominant clutter in one embodiment.
  • the propagation prediction system 1 is connected to the primary radio communication system 4 and the secondary radio communication system 5.
  • the primary wireless communication system 4 and the secondary wireless communication system 5 are external to the propagation prediction system 1
  • the primary wireless communication system 4 and the secondary wireless communication system 5 are propagation prediction systems. It does not necessarily exclude the case included in 1.
  • the primary wireless communication system 4 is a transmission / reception system of an FPU (Field Pickup Unit: wireless relay transmission device)
  • the FPU is used, for example, for material transmission for relaying and broadcasting a marathon.
  • the primary wireless communication system 4 includes a primary base station 41 and a primary mobile station 42.
  • the primary base station 41 and the primary mobile station 42 perform wireless communication using a predetermined frequency band assigned to the primary wireless communication system 4.
  • the secondary wireless communication system 5 is a cellular system.
  • the cellular system is used for wireless communication of, for example, mobile phones and smartphones.
  • the secondary wireless communication system 5 includes a secondary base station 51A, 51B, 51C, 51D, 51E, a secondary operation server 50 that controls the secondary base stations 51A, 51B, 51C, 51D, 51E, and a secondary mobile station (not shown).
  • a secondary base station 51A, 51B, 51C, 51D, and 51E may be simply referred to as the secondary base station 51.
  • the total number of secondary base stations 51 is 5, but the present embodiment is not limited to this total number. Further, the present embodiment is not limited to the total number of secondary mobile stations.
  • the secondary base station 51 and the secondary mobile station perform wireless communication using a predetermined frequency band assigned to the secondary wireless communication system 5.
  • the secondary wireless communication system 5 uses a frequency band that can interfere with the frequency band of the primary wireless communication system 4 .
  • the primary wireless communication system 4 preferentially uses the frequency in this band with respect to the secondary wireless communication system 5, and the secondary wireless communication system 5 uses the frequency in the same band within a range that does not interfere with the primary wireless communication system 4. do.
  • This frequency band may be, for example, a frequency band used in 5G (fifth generation mobile communication system).
  • the propagation prediction system 1 controls the suppression of interference from the secondary wireless communication system 5 to the primary wireless communication system 4 by predicting the propagation loss between the primary wireless communication system 4 and the secondary wireless communication system 5. Therefore, first, the propagation prediction system 1 acquires operational information from each of the primary wireless communication system 4 and the secondary wireless communication system 5.
  • the primary operation information 44 of the primary wireless communication system 4 may be provided to the propagation prediction system 1 from the primary base station 41, or may be provided to the propagation prediction system 1 from a primary operation server (not shown).
  • the secondary operation information 54 of the secondary wireless communication system 5 is provided to the propagation prediction system 1 from the secondary operation server 50 included in the secondary wireless communication system 5.
  • the propagation prediction system 1 predicts the propagation loss of each secondary base station 51 based on these operational information, and makes the interference power from the secondary base station 51 to the primary base station 41 equal to or less than a desired threshold value. Control is performed to limit the operation of the wireless communication system 5. This threshold may be determined based on the protection norms for protecting the primary radio communication system 4. Further, in this control, the propagation prediction system 1 generates and outputs an output signal 14 according to the propagation loss of each secondary base station 51, and the secondary operation server 50 stops each of the secondary base stations 51 based on the output signal 14. Alternatively, it may be performed by operating it.
  • the propagation prediction system 1 calculates the propagation loss between the primary wireless communication system 4 and the secondary wireless communication system 5 in order to calculate this interference power. In order to calculate this propagation loss, the propagation prediction system 1 refers to the three-dimensional map information of the area where the primary wireless communication system 4 and the secondary wireless communication system 5 are arranged.
  • the three-dimensional map information includes position information indicating the horizontal position and altitude of the clutter arranged between the primary wireless communication system 4 and the secondary wireless communication system 5.
  • Clutter is a general term for objects other than topography that exist on the surface of the earth, and refers to, for example, buildings and vegetation.
  • the position information of the clutter may represent the horizontal position and altitude of the apex where the diffraction of the electromagnetic wave can occur in the clutter.
  • the three-dimensional map information includes the position information indicating the horizontal position and altitude of the primary wireless communication system 4, particularly the primary base station 41, and the horizontal position of the secondary wireless communication system 5, particularly the secondary base station 51. It also includes location information that represents altitude.
  • the position information of the primary base station 41 may represent the horizontal position and altitude of the antenna included in the primary base station 41.
  • the position information of the secondary base station 51 may represent the horizontal position and altitude of the antenna included in the secondary base station 51.
  • the propagation prediction system 1 may hold the three-dimensional map information of the area where the primary wireless communication system 4, the secondary wireless communication system 5 and the clutter are arranged in advance, or acquire it from the outside as needed. May be good.
  • the server 2 includes a bus 21, an input / output device 22, an arithmetic unit 23, a storage device 24, and an external storage device 25.
  • the input / output device 22 inputs / outputs information, signals, etc. to / from the external configuration of the server 2.
  • the arithmetic unit 23 can realize a predetermined function by reading and executing the program stored in the storage device 24.
  • the storage device 24 stores programs, data, and the like to be read by the arithmetic unit 23 in order to realize a predetermined function.
  • the external storage device 25 can read programs, data, and the like from the recording medium 26, and can write the programs, data, and the like to the recording medium 26.
  • the recording medium 26 may be non-temporary and tangible.
  • the input / output device 22, the arithmetic unit 23, the storage device 24, and the external storage device 25 can communicate with each other via the bus 21.
  • the server 2 includes a communication unit 201, a clutter selection unit 202, a propagation loss calculation unit 203, and a control unit 204.
  • Each of the communication unit 201 and the control unit 204 is a functional unit realized by the input / output device 22, the arithmetic unit 23, and the storage device 24 in cooperation with each other.
  • Each of the clutter selection unit 202 and the propagation loss calculation unit 203 is a functional unit realized by the arithmetic unit 23 and the storage device 24 in cooperation with each other.
  • the functions of the communication unit 201, the clutter selection unit 202, the propagation loss calculation unit 203, and the control unit 204 will be described later.
  • step S01 is executed, and the three-dimensional map information is prepared in the storage device 24.
  • the three-dimensional map information includes the primary wireless communication system 4 including the primary base station 41, the secondary wireless communication system 5 including the secondary base station 51, and the clutter of the primary base station 41 and the secondary base station 51. It belongs to the area where it is located. A part or all of the three-dimensional map information may be read from the outside by the communication unit 201 of the server 2 and stored in the storage device 24.
  • Step S02 is executed after step S01, and the communication unit 201 of the server 2 acquires the primary operation information 44 from the primary base station 41 or the primary operation server, and acquires the secondary operation information 54 from the secondary operation server 50.
  • the primary operation information 44 includes the horizontal position and altitude of the primary base station 41, the frequency band used by the primary radio communication system 4, the strength of the radio signal transmitted from the primary mobile station 42 and reaching the primary base station 41, and the primary radio communication system.
  • Various information indicating the time zone in which 4 operates may be included.
  • the secondary operation information 54 includes the horizontal position and altitude of the secondary base station 51, the frequency band used by the secondary wireless communication system 5, the strength of the radio signal transmitted from the secondary base station 51, and the secondary base station 51, respectively.
  • Information indicating the horizontal position and altitude of each of the primary base station 41 and the secondary base station 51 may be supplied from any one of the three-dimensional map information, the primary operation information 44, and the secondary operation information 54. However, it may be supplied in duplicate from a plurality of units. With respect to the operation information supplied in duplicate, which operation information the server 2 adopts may be appropriately determined based on criteria such as, for example, the latest operation information being adopted.
  • Step S03 is executed after step S02, and the clutter selection unit 202 of the server 2 is placed between the primary base station 41 and the secondary base station 51 from among the clutters arranged between the primary base station 41 and the secondary base station 51.
  • Election a dominant clutter whose effect on propagation loss is dominant.
  • FIG. 4 an example of a method of selecting a dominant clutter in one embodiment will be described.
  • three clutters 63, 64, and 65 are present between the first antenna 61 of the primary base station 41 and the second antenna 62 of the secondary base station 51.
  • the altitudes of the first antenna 61 and the second antenna 62 are the same, but the present embodiment is not limited to this example.
  • Each of the clutters 63, 64, and 65 is arranged so as to have a portion that blocks a virtual straight path 612 connecting the first antenna 61 and the second antenna 62.
  • each of the clutters 63, 64, and 65 is arranged between the first antenna 61 and the second antenna 62, and the altitude thereof is higher than the altitudes of the first antenna 61 and the second antenna 62.
  • the electromagnetic wave emitted from the first antenna 61 can reach the second antenna 62 by diffracting at the ends of the clutters 63, 64, and 65.
  • the electromagnetic wave radiated from the second antenna 62 can reach the first antenna 61 by diffracting at the ends of the clutters 63, 64, 65.
  • diffraction causes propagation loss.
  • the clutters 63, 64, and 65 have vertices 631, 641, and 651, respectively.
  • the propagation loss may be calculated in consideration of all the diffractions generated at these vertices 631, 641, and 651, but the amount of calculation for that purpose can be relatively enormous. Therefore, in the present embodiment, among the clutters arranged between the first antenna 61 and the second antenna 62, the first dominant clutter, in which the influence of the propagation loss on the first antenna 61 is dominant, and the first.
  • the approximation is made by selecting the second dominant clutter in which the influence of the propagation loss on the two antennas 62 is dominant, and ignoring the propagation loss caused by the remaining clutter.
  • the clutter 64 is selected as the first dominant clutter corresponding to the first antenna 61.
  • the criterion for selection is that the clutter has the maximum elevation angle when the vertices 631, 641 and 651 of the clutter 63, 64 and 65 are viewed from the first antenna 61.
  • the path 613 which is a straight line connecting the first antenna 61 and the apex 631 of the clutter 63 is blocked by the clutter 64
  • the path 615 which is a straight line connecting the first antenna 61 and the apex 651 of the clutter 65 is also blocked by the clutter 64. It is blocked.
  • the path 614 which is a straight line connecting the first antenna 61 and the apex 641 of the clutter 64, is not blocked by the other clutters 63 and 65. Therefore, it is considered that the propagation loss of the electromagnetic wave transmitted and received by the first antenna 61 is larger when diffracted by the clutter 64 than when diffracted by the clutter 63 or 65.
  • the clutter 65 is selected as the second dominant clutter corresponding to the second antenna 62.
  • the criterion for selection is that the clutter has the maximum elevation angle when the vertices 631, 641 and 651 of the clutter 63, 64 and 65 are viewed from the second antenna 62.
  • the path 623 which is a straight line connecting the second antenna 62 and the apex 631 of the clutter 63, is blocked by the clutters 64 and 65
  • the path 624 which is a straight line connecting the second antenna 62 and the apex 641 of the clutter 64, is a clutter. It is blocked by 65.
  • the path 615 which is a straight line connecting the second antenna 62 and the apex 651 of the clutter 65, is not blocked by the other clutters 63 and 64. Therefore, it is considered that the propagation loss of the electromagnetic wave transmitted and received by the second antenna 62 is larger when diffracted by the clutter 65 than when diffracted by the clutter 63 or 64.
  • the clutter having the maximum clearance coefficient of the clutter with respect to the antenna may be used as the dominant clutter.
  • the clearance coefficient is a parameter related to the loss that the electromagnetic wave propagates through the obstacle.
  • the propagation loss of the propagation path between the first antenna 61 and the second antenna 62 is the first.
  • the components excluding the clutter loss due to the 1 dominant clutter 64 and the 2nd dominant clutter 65 are calculated and / or predicted by approximating the free space loss.
  • the propagation loss at 645 and path 614 is approximated to the propagation loss in free space at the distance of path 612.
  • the propagation path between the first antenna 61 and the second antenna 62 is a free space at a distance of the path 612.
  • the propagation loss is approximated. calculate.
  • the propagation loss in each of the path 625, the path 645, and the path 614 is the propagation loss in the free space of the same distance. May be good.
  • the first antenna 61 and the second antenna 62 are arranged by selecting the first dominant clutter 64 corresponding to the first antenna 61 and the second dominant clutter 65 corresponding to the second antenna 62. It is estimated that the propagation path between them is a set of paths 625, 645 and 614 that pass through the apex 641 of the first dominant clutter 64 and the apex 651 of the second dominant clutter 65.
  • Non-Patent Document 1 (ITU-R (Radiocommunication Sector of International Telecommunication Union), "Recommunication ITU-R P.2108-0 (06/2017) Radiocommunication , [Online], June 20, 2017, Internet ⁇ URL: https://www.itu.int/dms_pubrec/itu-r/rec/p/R-REC-P.2108-0-201706-I !!
  • the clutter model defined in PDF-E.pdf> has been improved. By doing so, in the present embodiment, the propagation loss can be accurately calculated and / or predicted.
  • the clutter selection unit 202 selects a plurality of second dominant clutters corresponding to the plurality of secondary base stations 51, respectively.
  • the clutter selection unit 202 stores information representing the selected dominant clutter in the storage device 24.
  • step S04 is executed after step S03, and the propagation loss calculation unit 203 of the server 2 interferes with the primary base station 41 in the frequency band used by the secondary base station 51. Calculate the propagation loss at frequencies included in the frequency band where can occur.
  • the first clutter loss which is a component caused by the first dominant clutter, is the distance from the primary base station 41 to the first dominant clutter and the primary. It can be calculated based on the respective altitudes of the base station 41 and the first dominant clutter.
  • the second clutter loss which is a component caused by the second dominant clutter, is the distance from the secondary base station 51 to the second dominant clutter. And the altitude of each of the secondary base station 51 and the second dominant clutter.
  • clutter loss A h is the standard model of non-patent document 1 is defined by the following (1a) formula and (1b) Formula (suburban, urban, trees, forests, dense urban) and has units of dB (Decibel).
  • J ( ⁇ ) is a parameter related to the loss due to diffraction, and its unit is dB.
  • ⁇ is the clearance coefficient of the dominant clutter, and its unit is dimensionless.
  • "6.03” is an approximated constant, and depending on the approximated condition, for example, “6.02", “6.04", "any numerical value from 6.00 to 6.06", etc. , Can be changed to another value.
  • "H” is the altitude of the antenna, and its unit is m (meter).
  • R” is the altitude of the dominant clutter 64 corresponding to this antenna, the unit of which is m.
  • each of the altitude h of the antenna and the altitude R of the dominant clutter 64 shown in FIG. 5 are altitudes with respect to the same horizontal plane. These altitudes may be defined as above sea level, or may be defined by adding the altitude above sea level to the height above sea level, but the present embodiment is not limited to these examples. In either case, since the difference between the altitude h and the altitude R is used in the calculation of the clutter loss and / or the propagation loss in the present embodiment, the altitude of the reference horizontal plane may be arbitrary.
  • Equation (1a) is applied when the condition of "h ⁇ R" is satisfied, that is, when the dominant clutter blocks the virtual straight line connecting the first antenna 61 and the second antenna 62. Further, the equation (1b) is applied when the condition of "h ⁇ R" is satisfied, that is, when the electromagnetic wave can be directly propagated along this virtual straight line between the first antenna 61 and the second antenna 62. Will be done.
  • the calculation method of the equation (1a) will be described.
  • the clearance coefficient ⁇ used in the equation (2) is defined as the following equation (3).
  • K nu is a parameter related to frequency.
  • h dif is the difference between the altitude R of the dominant clutter 64 and the altitude h of the first antenna 61, and the unit thereof is m.
  • ⁇ cult is an elevation angle when the apex 641 of the dominant clutter 64 is viewed from the first antenna 61, and the unit thereof is deg (degrees).
  • the value of the elevation angle when looking above the horizontal direction is positive, but the depression angle when looking below the horizontal direction may be treated as an elevation angle having a negative value.
  • the frequency parameter K nu used in the equation (3) is defined as the following equation (4).
  • "f” is a frequency, and its unit is GHz (gigahertz).
  • the altitude difference h def used in the equation (3) is defined as the following equation (5).
  • the elevation angle ⁇ clut used in the equation (3) is defined as the following equation (6).
  • "w s" as shown in FIG. 5, a horizontal distance to the vertex 641 of the dominant clutter 64 from the first antenna 61, the unit is m.
  • the distance w s may correspond to a parameter defined as a road width in the standard model of Non-Patent Document 1.
  • the dominant in this frequency band is based on the position and altitude information of each of the first antenna 61 and the dominant clutter 64 and the value of the frequency contained in the frequency band used.
  • the clutter loss due to the clutter 64 can be calculated.
  • the clutter loss can be similarly calculated for the dominant clutter corresponding to the second antenna 62.
  • the propagation path from the primary base station 41 to the secondary base station 51 is approximated to free space.
  • this propagation path is divided by the dominant clutter 64 and the second dominant clutter 65
  • the propagation path to the two dominant clutter 65 and the propagation path from the second dominant clutter 65 to the secondary base station 51 are approximated to free space, respectively.
  • the propagation loss that is, the free space loss in each of these free spaces is defined by the following equation (7).
  • L 0 is a free space loss, the unit of which is dimensionless, but the propagation loss of the unit is dB by calculating 10 times its log (logarithm with a base of 10). Can be calculated.
  • D is the distance at which the electromagnetic wave propagates in the propagation path as a free space, and its unit is m.
  • ⁇ is a wavelength corresponding to the frequency used, and its unit is m.
  • the overall propagation loss from the primary base station 41 to the secondary base station 51 is predicted. be able to.
  • Step S05 is executed after step S04, and the control unit 204 of the server 2 generates an output signal 14 according to the propagation loss calculated in step S04 and outputs the output signal 14 to the secondary operation server 50.
  • the propagation loss threshold value may be set so that the interference power from the secondary base station 51 to the primary base station 41 exceeds another predetermined threshold value.
  • the interference power can be calculated from the power and propagation loss of the radio signal transmitted from the secondary base station 51.
  • the output signal 14 output by the control unit 204 may be a control signal for the secondary operation server 50 to stop the secondary base station 51 in which the interference power to the primary base station 41 exceeds a predetermined protection standard.
  • the secondary operation server 50 may stop the secondary base station 51 in which the interference power to the primary base station 41 exceeds a predetermined protection standard in response to the output signal 14.
  • step S05 When step S05 is completed, the flowchart of FIG. 3 ends.
  • FIG. 6 another example of the method of selecting the dominant clutter in one embodiment will be described.
  • the example of FIG. 6 is the example of FIG. 4 with the following changes added. That is, the altitude of the clutter 65 is lowered.
  • the second dominant clutter corresponding to the second antenna 62 was the clutter 65 in the example of FIG. 4, but the clutter 64 in the example of FIG.
  • the first dominant clutter corresponding to the first antenna 61 is the clutter 64 in FIG. 6 as in the case of FIG. That is, in the example of FIG. 6, the first dominant clutter and the second dominant clutter are the same clutter 64.
  • the calculation of the propagation loss of the dominant clutter in step S04 of the flowchart of FIG. 3 is performed when the first dominant clutter 64 and the second dominant clutter 65 are different clutters as illustrated in FIG.
  • the first dominant clutter 64 and the second dominant clutter 64 may be the same dominant clutter 64 as illustrated in the above, and may be performed by different methods. An example of such a modification will be described with reference to the flowchart of FIG.
  • step S11 is executed, and the propagation loss calculation unit 203 determines whether the first dominant clutter and the second dominant clutter are the same clutter. In order to make this determination, the propagation loss calculation unit 203 may read out the result of selecting the dominant clutter stored in the storage device 24 by the clutter selection unit 202.
  • step S12 is executed after step S11. ..
  • the propagation loss calculation unit 203 calculates the overall propagation loss between the first antenna 61 of the primary base station 41 and the second antenna 62 of the secondary base station 51 as follows.
  • the first clutter loss and the second clutter loss due to the diffraction generated in the first dominant clutter 64 and the second dominant clutter 65 are each used by equations (1a) to (7). To calculate.
  • step S12 When step S12 is completed, the flowchart of FIG. 7 ends, and the process proceeds to step S05 of the flowchart of FIG.
  • the propagation loss calculation unit 203 calculates the overall propagation loss between the first antenna 61 of the primary base station 41 and the second antenna 62 of the secondary base station 51 as follows.
  • the clutter loss in the same dominant clutter 64 is the shorter of the first distance from the primary base station 41 to the dominant clutter 64 and the second distance from the secondary base station 51 to the dominant clutter 64.
  • the clutter loss of the dominant clutter 64 is calculated based on the distance of.
  • the propagation path from the primary base station 41 to the first dominant clutter 64 and the propagation path from the first dominant clutter 64 to the second antenna 62 are approximated to free space, respectively.
  • the free space loss in each of these free spaces is defined as the above-mentioned equation (7).
  • step S13 When step S13 is completed, the flowchart of FIG. 7 ends, and the process proceeds to step S05 of the flowchart of FIG.
  • the dominant clutter corresponding to the first antenna 61 and the second antenna 62 is the same clutter depending on whether or not the flowchart of FIG. 7 is processed, the clutter caused by this dominant clutter. It is possible to select whether the loss is added once or twice in the overall propagation loss between the first antenna 61 and the second antenna 62. This selection may be made depending on the shape of the apex of the dominant clutter and the like. As an example, if the dominant clutter is a rectangular parallelepiped building or the like and there is a sufficiently long distance between the apex facing the first antenna 61 and the apex facing the second antenna 62, FIG. 7 shows. If the flow chart is not processed, the accuracy of predicting the propagation loss may be higher. On the contrary, if the distance between the apex facing the first antenna 61 and the apex facing the second antenna 62 is sufficiently short, the flow chart processing of FIG. 7 is more accurate in predicting the propagation loss. May be higher.
  • step S21 is executed, and the propagation loss calculation unit 203 determines whether or not the altitude of the dominant clutter is equal to or higher than the threshold value.
  • the propagation loss calculation unit 203 may read out the selection result of the dominant clutter stored in the storage device 24 by the clutter selection unit 202 in step S03 of the flowchart of FIG. Further, the propagation loss calculation unit 203 may read out the altitude of the dominant clutter stored in the database or the storage device 24 (not shown).
  • step S22 is executed after step S21.
  • the propagation loss calculation unit 203 replaces the altitude of this dominant clutter with this threshold value.
  • step S22 is completed, the flowchart of FIG. 8A ends, processing returns to step S04 of the flowchart of FIG. 3 or step S12 or step S13 of the flowchart of FIG. 7, and the propagation loss calculation unit 203 dominates the replaced altitude.
  • the clutter loss and propagation loss are calculated using the clutter altitude.
  • step S21 if the altitude of the dominant clutter selected in step S03 is less than a predetermined threshold value (No), the flowchart of FIG. 8A ends, and the process is performed in step S04 or the flowchart of FIG.
  • the propagation loss calculation unit 203 calculates the clutter loss and the propagation loss by using the altitude that has not been replaced as the altitude of the dominant clutter.
  • step S31 is executed, and the propagation loss calculation unit 203 determines whether or not the altitude difference between the dominant clutter and the corresponding base station is equal to or greater than the threshold value.
  • the propagation loss calculation unit 203 may read out the selection result of the dominant clutter stored in the storage device 24 by the clutter selection unit 202 in step S03 of the flowchart of FIG. Further, the propagation loss calculation unit 203 may read out the altitudes of the primary base station 41, the secondary base station 51, and the dominant clutter stored in the database or the storage device 24.
  • step S32 is executed after step S31.
  • the propagation loss calculation unit 203 replaces the altitude of the dominant clutter with a value at which the altitude difference is equal to the threshold value.
  • step S32 is completed, the flowchart of FIG. 8B ends, processing returns to step S04 of the flowchart of FIG. 3 or step S12 or step S13 of the flowchart of FIG. 7, and the propagation loss calculation unit 203 dominates the replaced altitude.
  • the clutter loss and propagation loss are calculated using the clutter altitude.
  • step S31 when the altitude of the dominant clutter selected in step S03 is less than a predetermined threshold value (No), the flowchart of FIG. 8B ends, and the process is performed in step S04 or the flowchart of FIG.
  • the propagation loss calculation unit 203 calculates the clutter loss and the propagation loss by using the altitude that has not been replaced as the altitude of the dominant clutter.
  • diffraction at the apex of the dominant clutter is performed by using an appropriate altitude threshold as the threshold of the altitude of the dominant clutter, as in the case of FIG. 8A.
  • an appropriate altitude threshold as the threshold of the altitude of the dominant clutter
  • This process requires a relatively small amount of calculation as a method for calculating the propagation loss due to diffraction on the side surface of the dominant clutter, and further leads to accurate prediction of the propagation loss.
  • the dominant clutter is selected as a preliminary step. Sometimes the same replacement is done. This will be described with reference to FIG. 8C.
  • step S41 the clutter selection unit 202 refers to the map information, lists the information of the clutter existing between the primary base station 41 and the secondary base station 51, and initializes the order of processing the clutter.
  • the order in which the clutter is processed may be, for example, the order closest to the primary base station.
  • the argument representing the order is initialized to zero, and the argument representing the total number of clutters listed is stored.
  • step S42 the clutter selection unit 202 reads the next clutter information from the clutter information listed. At this time, the argument indicating the order of processing the clutter is incremented.
  • step S43 it is determined whether or not the value obtained by subtracting the reference altitude from the altitude of the clutter from which the information is read is larger than a predetermined threshold value.
  • the reference altitude is equal to this altitude when the first antenna 61 of the primary base station 41 and the second antenna 62 of the secondary base station 51 have the same altitude.
  • the altitude of the point closest to the apex of the clutter included in the virtual straight line connecting the first antenna 61 and the second antenna 62. Is.
  • the value obtained by subtracting the reference altitude from the altitude of the clutter is equal to the vertical length from the apex of the clutter to the virtual straight line.
  • step S44 if the value obtained by subtracting the reference altitude from the altitude of the clutter from which the information is read is larger than the predetermined threshold value (Yes), the altitude of the clutter is set to another lower altitude in step S44. After the replacement, the process proceeds to step S45. On the contrary, when the value obtained by subtracting the reference altitude from the altitude of the clutter from which the information is read is not larger than the predetermined threshold value (No), the process proceeds to step S45 without executing step S44.
  • step S45 it is determined whether or not all the clutter information has been read. In other words, it is determined whether the argument indicating the order in which the clutters are processed has reached the argument indicating the total number of clutters listed. As a result of the determination, if all the clutter information has been read (Yes), the process proceeds to step S46. On the contrary, when the clutter for which the information has not been read remains (No), the process returns to step S42.
  • step S46 the clutter selection unit 202 extracts the dominant clutter. This operation is as shown in step S03 of the flowchart of FIG. When step S46 is completed, the flowchart of FIG. 8C ends, and the process proceeds to step S04 of the flowchart of FIG.
  • both the processing for extracting the dominant clutter and the processing for calculating the clutter loss derived from the dominant clutter are performed by similarly replacing the altitude of the clutter. Consistency can be achieved between processes.
  • the altitude h eb of the first antenna 61 is higher than the high R e of the clutter 66 influence the propagation loss is dominant for the first antenna 61, high R e of the dominant clutter 66 second 2 Higher than the altitude h et of the antenna 62.
  • each of these advanced h eb, h et, R e a highly referenced to the same horizontal plane.
  • this standard may be above sea level or at a height above the ground surface, but the present embodiment is not limited to these examples.
  • a virtual straight line connecting the first antenna 61 and the second antenna 62 is not horizontal.
  • the path 612 of the virtual straight line It may block.
  • the electromagnetic wave radiated from the second antenna 62 via the path 616 connecting the first antenna 61 and the apex 661 of the dominant clutter and the path 626 connecting the apex 661 and the second antenna 62 is the first antenna. 61 can be reached.
  • the altitude heb of the first antenna 61 and the altitude h et of the second antenna 62 are different by correcting the equation used for calculating the propagation loss in the first embodiment as follows. Even in this case, it is possible to calculate the propagation loss.
  • the definition of the clearance coefficient ⁇ is corrected from the equation (3) used in the first embodiment to the following equation (8).
  • K nu is a parameter related to the frequency defined in equation (4).
  • the “ h'dif ” is the length obtained by correcting the altitude difference h div of the above-mentioned equation (5).
  • the " ⁇ 'clut " is an angle corrected by the elevation angle ⁇ clut of the above-mentioned equation (6).
  • the length h'dim of the equation (8) is the length in the vertical direction from the apex 661 of the dominant clutter 66 to the virtual straight line connecting the first antenna 61 and the second antenna 62. And the unit is m.
  • the definition of the length h'dim is a correction of the definition of h def according to the equation (5) used in the first embodiment as shown in the following equation (9).
  • "R e" is highly dominant clutter 66
  • the unit is m.
  • “H et ” is the altitude of the second antenna 62, and its unit is m.
  • “H eb ” is the altitude of the first antenna 61, and its unit is m.
  • W s is the distance in the horizontal direction to the dominant clutter 66 from the first antenna 61, the unit is m.
  • D is the horizontal distance from the first antenna 61 to the second antenna 62, and the unit thereof is m.
  • Theta tr is the angle between the horizontal direction and the path 612 of a virtual straight line connecting the first antenna 61 and the second antenna 62, and the unit is deg (degrees).
  • the angle ⁇ 'clut in the equation (8) is a virtual straight line path 612 connecting the first antenna 61 and the second antenna 62, and the apex 661 of the first antenna 61 and the dominant clutter 66. It is an angle between the path 616 of a virtual straight line connecting the two, and its unit is deg (degree).
  • the definition of the angle ⁇ 'clut is a correction of the definition of the elevation angle ⁇ clut according to the equation (6) used in the first embodiment as shown in the following equation (11).
  • the angle ⁇ 'clut is an elevation angle obtained from the first antenna 61 as seen from the apex 661 of the dominant clutter 66 when the path 612 of a virtual straight line connecting the first antenna 61 and the second antenna 62 is used as a reference. Can be regarded as.
  • the propagation loss can be calculated accurately.
  • the following changes are made as modified examples of the first embodiment and the second embodiment. That is, in the propagation loss between the primary base station 41 and the secondary base station 51, the first clutter loss which is a component caused by the first dominant clutter and the second clutter loss which is a component caused by the second dominant clutter.
  • the propagation loss is calculated by considering only one of the first clutter loss and the second clutter loss. At this time, of the first clutter loss and the second clutter loss, the other one not considered in the calculation of the propagation loss is replaced with the free space loss when calculating the propagation loss.
  • the definition of free space loss is as in Eq. (7) above.
  • the propagation loss is calculated by considering the smaller loss of the first clutter loss and the second clutter loss and replacing the larger loss with the free space loss.
  • the propagation loss is calculated by considering the larger loss of the first clutter loss and the second clutter loss and replacing the smaller loss with the free space loss. do.
  • the prediction of propagation loss can be accurately predicted, in particular, when a margin is set for the signal output when the frequency is shared between the primary wireless communication system 4 and the secondary wireless communication system 5. It can be carried out.
  • the clutter loss may be calculated using the three-dimensional map information which is divided into a plurality of areas and the altitude information is registered for each area.
  • the altitude information registered in these areas is the representative altitude of each area, and may be, for example, the average altitude in the area.
  • the selection of the dominant clutter and the calculation of the clutter loss due to the dominant clutter may be performed assuming that the clutter of the representative altitude exists at the representative position of each region, for example, at the geometric center position.
  • the region where the elevation angle of the region is maximum when viewed from the antenna is selected as the dominant region, and the distance from the antenna to the representative position of the dominant region, the height of the antenna, and the representative altitude are used. Then, the component due to the dominant region of the propagation loss may be calculated. Further, the area where the primary base station 41 and the secondary base station 51 are arranged is horizontally divided into a plurality of meshes with a predetermined unit length, and the average value of the altitudes of the clutter included in each mesh is calculated as the altitude of each mesh. Can be treated as. In this case, in step S03 of the flowchart of FIG.
  • the altitude of the clutter arranged between the primary base station 41 and the secondary base station 51 is set to the altitude of the mesh arranged between the primary base station 41 and the secondary base station 51. It can be highly replaced to elect the dominant mesh instead of the dominant clutter. Further, in step S04 of the flowchart of FIG. 3, the altitude of the dominant clutter can be replaced with the altitude of the dominant mesh, and the clutter loss and the propagation loss can be calculated.
  • a model of the clutter a model having a vertex at the uppermost position has been described, but the present disclosure is not limited to this, and it may be a structure formed in a rectangular parallelepiped shape, for example, a building.
  • the position of the geometric center of the building may be used as the position of the clutter, or the position of the wall surface on the side close to the antenna may be used.
  • a model may be adopted in which the apex of the clutter is directly above the position of the clutter and has the altitude of the clutter.
  • control unit 204 may generate and output an output signal 14 for displaying the propagation loss calculated in step S04 on an arbitrary display device.
  • the user of the propagation prediction system 1 may control the secondary base station 51 via the secondary operation server 50 according to the propagation loss displayed on the display device.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
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  • Quality & Reliability (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Grâce à la présente invention, la perte de propagation entre deux systèmes de communication sans fil est prédite avec précision. Parmi les fouillis placés entre deux stations de base, un fouillis dominant, dont l'angle d'élévation est maximal lorsque le sommet du fouillis est vu de chaque station de base, est sélectionné. Selon la distance entre chaque station de base et chaque fouillis dominant et leurs altitudes, une perte de fouillis de la perte de propagation d'une voie de propagation entre les deux stations de base est calculée, la perte de fouillis étant une composante résultant du fouillis dominant. Les composantes de la perte de propagation sont, à l'exclusion de la perte de fouillis, approximées à une perte d'espace libre pour prédire la perte de propagation. Un signal de sortie est émis selon la perte de propagation.
PCT/JP2021/010539 2020-06-25 2021-03-16 Système de prédiction de propagations, procédé de prédiction de propagations et support d'enregistrement stockant un programme de prédiction de propagations WO2021261031A1 (fr)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004508781A (ja) * 2000-09-07 2004-03-18 エリクソン　インコーポレイテッド 累積クラッタ経路損失を決定するシステムと方法
CN101098537A (zh) * 2006-06-30 2008-01-02 中兴通讯股份有限公司 一种无线通信中绕射损耗计算的方法
KR20140044658A (ko) * 2012-10-05 2014-04-15 티앤비전파기술 주식회사 전파의 전파 경로 분석 방법 및 장치

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JP2004508781A (ja) * 2000-09-07 2004-03-18 エリクソン　インコーポレイテッド 累積クラッタ経路損失を決定するシステムと方法
CN101098537A (zh) * 2006-06-30 2008-01-02 中兴通讯股份有限公司 一种无线通信中绕射损耗计算的方法
KR20140044658A (ko) * 2012-10-05 2014-04-15 티앤비전파기술 주식회사 전파의 전파 경로 분석 방법 및 장치

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