Simulation device and program

Abstract

To speed up processing for calculating radio-wave propagation characteristics even when propagation paths of radio waves vary on the basis of changes in object positions within a computation target area.SOLUTION: A simulation device 1 includes a computation unit 2 that calculates propagation characteristics of radio waves propagating between a transmission unit that radiates radio waves and a reception unit that receives the radio waves in a target region in which objects are present. The computation unit calculates one or more propagation paths of the radio waves propagating from any first position in the target region to a second position different from the first position, calculates a first propagation characteristic of the radio waves received at the second position on the basis of the propagation paths, places the second position at locations of a plurality of grid points set within the target region, executes a first simulation that repeatedly calculates the plurality of first propagation characteristics, and stores first calculation results of the first simulation in a storage unit.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a simulation device and a program capable of calculating the propagation state of radio waves.

Background Art

[0002] In a wireless communication network, the quality of wireless communication varies due to the effects of diffraction, reflection, interference, transmission, etc. on radio waves in the radio wave propagation path. Conventionally, as a method for predicting the quality in a communication area of a wireless network, radio wave propagation simulation methods such as the ray tracing method are known (see, for example, Non-Patent Document 1 and Non-Patent Document 2). The ray tracing method is a method for calculating, by simulation, the propagation characteristics of radio waves between two nodes that transmit and receive radio waves.

[0003] In the ray tracing method, first, a three-dimensional environment model related to the communication area is input into a computer. The above three-dimensional model uses data of an existing geographic information system or building system, or is created by a computer. Next, using the information of the transmission and reception points arranged in the three-dimensional environment model, the propagation path of radio waves (rays) between the transmission and reception points is calculated. Rays are affected by reflection, diffraction, and transmission by objects existing in the environment. In order to calculate accurate radio wave propagation channel information in the simulation, it is necessary to input the accurate positions and shapes of the objects existing in the radio wave propagation path into the computer.

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] When applying the ray tracing method to an area where there are moving objects, it is necessary to reconstruct the three-dimensional environmental model according to the movement state of the objects and repeatedly perform simulations regarding radio wave propagation. For example, when applying the ray tracing method to an area where there are objects that do not stay in one place, such as pedestrians and vehicles, and conducting an evaluation taking into account the influence of these moving objects, it is necessary to repeatedly perform simulations regarding radio wave propagation. Therefore, when calculating the radio wave propagation characteristics of an area where there are moving objects based on existing simulation methods, there are problems that the amount of calculation increases and the calculation process becomes complicated.

[0006] An object of the present invention is to provide a simulation apparatus and a program capable of accelerating a process of calculating radio wave propagation characteristics even when the radio wave propagation path varies based on a change in the position of an object in a calculation target area.

Means for Solving the Problems

[0007] One aspect of the present invention includes an arithmetic unit that calculates the propagation characteristics of radio waves propagating between a transmission unit that radiates radio waves and a reception unit that receives the radio waves in a target area where an object exists. The arithmetic unit calculates one or more propagation paths of the radio waves propagating from an arbitrary first position in the target area to a second position different from the first position, and calculates a first propagation characteristic of the radio waves received at the second position based on the propagation paths. The second position is arranged at the positions of a plurality of grid points set in the target area, and a first simulation for repeatedly calculating a plurality of the first propagation characteristics is executed, and a first calculation result of the first simulation is stored in a storage unit. It is a simulation device.

Effects of the Invention

[0008] According to the present invention, it is possible to significantly reduce the amount of calculation and the calculation time required for simulation for evaluating the performance of a wireless communication system in an actual communication area.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

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Embodiment for Carrying Out the Invention

[0010] As shown in FIG. 1, the simulation device 1 is realized by an information processing device such as a personal computer, for example. The simulation device 1 is a device for executing a simulation for evaluating the performance of a wireless communication system in a communication area. The simulation device 1 includes an arithmetic unit 2 that executes arithmetic processing. The simulation device 1 includes a storage unit 3 in which data and programs necessary for the arithmetic operation are stored. The arithmetic unit is configured to execute a program stored in the storage unit 3 by a hardware processor such as a CPU (Central Processing Unit), for example.

[0011] The calculation unit 2 may be implemented by hardware (including circuitry) such as LSI (Large Scale Integration), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array), GPU (Graphics Processing Unit), etc., or may be implemented by the cooperation of software and hardware. The program may be stored in a storage device such as an HDD (Hard Disk Drive) or a flash memory that the storage unit 3 has in advance, or may be stored in a removable storage medium such as a DVD or a CD-ROM, and may be installed by attaching the storage medium to a drive device.

[0012] The simulation device 1 includes an input unit 5 for inputting information necessary for calculation. The input unit 5 is composed of, for example, a device for inputting information such as a keyboard device or a touch panel. The simulation device 1 includes a display unit 4 for outputting the calculation result calculated by the calculation unit 2. The display unit 4 is composed of, for example, a display device such as a liquid crystal display or an organic EL (Electro-Luminescence) display. The display unit 4 may be composed of a touch panel, and in that case, it may be configured as the input unit 5 by displaying a display image for receiving an input operation.

[0013] With the above configuration, the simulation device 1 calculates the propagation characteristics of radio waves in the communication area based on the information of the communication area to be calculated input to the input unit 5, and displays the calculation result on the display unit 4. The simulation device 1 calculates, for example, the propagation characteristics of radio waves propagating between a first position and a second position arranged in a modeled communication area based on the ray tracing method (see Non-Patent Document 1 and Non-Patent Document 2). The simulation device 1 is configured to execute a first simulation for generating a database in advance in calculating the propagation characteristics of radio waves in the communication area, and a second simulation for calculating the propagation characteristics of radio waves in the communication area at high speed using the first calculation result of the first simulation.

[0014] FIG. 2 shows a target area T simulating a communication area, which is used for the first simulation. The target area T is, for example, displayed as a display image on the display unit 4. The communication area may be an indoor facility or an outdoor facility. The target area T is a spatial model used for calculation. In the target area T, a space L through which radio waves propagate, a reflecting surface T1 on which radio waves are reflected, etc. are set. The target area T is set to an arbitrary shape according to the shape of the communication area to be calculated. The space L is, for example, air. The reflecting surface T1 is the wall surface of a building or the surface of an object. In the target area T, a first position C1 of a transmission unit that radiates radio waves and a second position C2 of a reception unit that receives radio waves are arranged.

[0015] The first position C1 is set, for example, in a transmission unit that radiates radio waves. The first position C1 is arranged at an arbitrary position within the target area T. The second position C2 is set, for example, in a reception unit that receives radio waves or an object affected by radio waves. The second position C2 is arranged at a position different from the first position C1. The second position C2 is arranged at the positions of a plurality of grid points K set within the target area T. The plurality of grid points K are set, for example, at positions in a matrix at equal intervals so that two-dimensional coordinates can be set within the target area T. The first position C1 may also be arranged at the position of the grid point K. The arrangement method of the grid points K is an example and may be arranged based on an arbitrary arrangement method.

[0016] The radio wave (ray) radiated from the first position C1 propagates to the second position C2 through a plurality of propagation paths. In the illustrated example, a propagation path S1 that directly propagates from the first position C1 to the second position C2 and a propagation path S2 of a reflected wave that is radiated from the first position C1, hits the reflecting surface T1, is reflected, and propagates to the second position C2 are shown. The illustrated propagation paths are an example, and two or more propagation paths may exist in the target area T.

[0017] The calculation unit 2 executes a simulation based on the ray tracing method for one grid point (second position). The calculation unit 2 calculates the first propagation characteristic of the radio wave propagating from the first position C1 to the second position C2 based on the received power P of the radio wave received at the second position C2.

[0018] The calculation unit 2 uses the following data to execute a simulation for calculating the first propagation characteristic of the radio wave for each of n (n: natural number) propagation paths at the second position. The emission angle of the radio wave at the first position C1: Φ Tx,i The incident angle of the radio wave at the second position C2: Φ Rx,i The complex amplitude of the received signal: s i The propagation delay of the received signal: τ i The received power P at the second position is defined by the following formula (1). P = Σ i s i (1)

[0019] The calculation unit 2 calculates one or more propagation paths that propagate from the first position C1 to the second position C2. For example, based on the received power P at the second position C2, the calculation unit 2 calculates the first propagation characteristics of the radio wave received at the second position C2. The calculation unit 2 places the second position C2 at the position of the grid point K set in the target area T and executes a first simulation that repeatedly calculates a plurality of first propagation characteristics. The calculation unit 2 places the second position at different grid point K positions and calculates different first propagation characteristics. For example, the calculation unit 2 rearranges the second position C2 at all the grid points K and repeatedly executes the calculation of the first propagation characteristics to calculate all the first propagation characteristics. The calculation unit 2 stores the first calculation result of the first simulation including the calculated plurality of first propagation characteristics in the storage unit 3.

[0020] The first calculation result of the first propagation characteristics is used as a database for executing a second simulation that calculates the second propagation characteristics of the radio wave between the first position C1 and the second position C2 when a new object is placed in the target area T.

[0021] FIG. 3 illustrates the target area T used in the second simulation. In the illustrated example, the target area T is set in a two-dimensional plane in the horizontal direction. The target area T has a reflecting surface T1 set according to the shape of the actual calculation target. In the target area T, there are a transmitting unit that radiates radio waves, a receiving unit that receives radio waves, and an object. The transmitting unit is arranged at the first position C1. The transmitting unit is, for example, a radio base station that transmits radio waves. The transmitting unit may be a moving body such as a communication terminal device that can move within the target area and transmits radio waves.

[0022] The object is arranged at an arbitrary second position. The object may be a stationary object such as a building existing in the target area, or a moving body such as a vehicle or a pedestrian. The receiving unit is arranged at the third position C3. The receiving unit is a moving body that receives radio waves such as a movable communication terminal device existing in the target area. The receiving unit may be a radio base station that receives radio waves within the target area.

[0023] The calculation unit 2 executes a second simulation that calculates the second propagation characteristics of radio waves propagating between the transmission unit and the reception unit based on the arrangement relationship among the transmission unit, the object, and the reception unit within the target area T using the ray tracing method. The calculation unit 2 calculates the second propagation characteristics of radio waves propagating from the transmission unit to the reception unit in a state where an object is arranged within the target area T. The calculation unit 2 calculates one or more propagation paths of radio waves propagating from the transmission unit (the first position C1) to the reception unit (the third position). In the example of Fig. 3(A), there are three propagation paths S1 to S3. At this time, the calculation unit 2 may utilize the first calculation result of the first simulation in calculating one or more propagation paths of radio waves propagating from the transmission unit to the reception unit.

[0024] The calculation unit 2 calculates the influence exerted by the object arranged at the second position C2 within the target area T on the propagation path. In the example of Fig. 3(B), the object is arranged at an arbitrary second position. The calculation unit 2 extracts the positions of the grid points Kp and kq (p, q: natural numbers) corresponding to the position of the object. The calculation unit 2 calculates the propagation path between the transmission unit and the object based on the influence of the object using the previously calculated first calculation result. The calculation unit 2 determines, for example, whether there exists a propagation path of radio waves propagating from the transmission unit at the positions of the grid points Kp and kq by utilizing the first calculation result corresponding to the positions of the grid points Kp and kq.

[0025] The calculation unit 2, for example, in a state where an object is arranged at the second position C2, refers to the first calculation result at the second position (grid point Kp), and determines that there exists a propagation path S1A through which radio waves reach the object by utilizing the first calculation result. The propagation path S1A from the transmission unit to the object indicates that the object shields the propagation path S1 at the position of the grid point Kp. The calculation unit 2 determines that there exists a propagation path S1 that is shielded between the transmission unit and the reception unit. When the calculation unit 2 determines that there exists a propagation path S1 that is shielded between the transmission unit and the reception unit, the calculation unit 2 calculates the shielding loss generated due to the existence of the propagation path shielded by the object among the propagation paths. The calculation unit 2 calculates the second propagation characteristics based on the calculation result of the shielding loss.

[0026] As shown in FIG. 4, for example, the calculation unit 2 calculates the knife-edge diffraction loss caused by the diffraction of radio waves by an object and calculates the shielding loss of the radio waves propagating to the receiving unit. The knife-edge diffraction loss is a method for calculating the diffraction loss of radio waves when the corner of an object blocking the line of sight of the radio waves is an ideal knife-edge with a conductive thickness that can be ignored. In the illustrated example, the knife-edge diffraction caused by an object with a cylindrical (r: radius) cross-section is shown. When knife-edge diffraction occurs, the radio waves propagating to the object diffract, and the diffracted waves with diffraction loss propagate along the propagation path S1d to the receiving unit (see FIG. 3(B)). The cross-sectional shape of the object may be not only cylindrical but also any shape. The calculation unit 2 calculates the influence of radio waves such as diffraction generated according to the cross-sectional shape of the object.

[0027] The calculation unit 2 calculates the knife-edge diffraction loss J(v) [dB] of the radio waves from the transmitting unit to the receiving unit by the object based on the following general formulas (2) and (3).

Equation

Equation

[0028] The calculation unit 2 adds the diffracted wave with diffraction loss caused by the influence of the object at the position of the grid point Kp and the other propagating radio waves, and calculates the propagation path of the radio waves between the transmission unit and the reception unit. The calculation unit 2 calculates the second propagation characteristic of the radio waves propagating from the transmission unit to the reception unit based on the radio wave intensity of the radio waves received by the reception unit based on the calculation result. The calculation unit 2 outputs the second calculation result of the second simulation to the display unit 4. When diffraction loss occurs due to the influence of a plurality of objects, the calculation unit 2 may add a plurality of diffracted waves with diffraction loss and the other propagating radio waves, and calculate the propagation path of the radio waves between the transmission unit and the reception unit.

[0029] When the shape of the object includes one or more grid points, the calculation unit associates the object with a grid point group including one or more grid points selected according to the shape of the object from among the plurality of grid points. The calculation unit 2 calculates a plurality of propagation losses for each grid point included in the grid point group using the first calculation result, and calculates a plurality of second propagation characteristics between the transmission unit and the reception unit affected by the grid point group. The calculation unit 2 calculates the second propagation characteristic of the radio waves propagating between the transmission unit and the reception unit affected by the grid point group based on the calculation results of the plurality of second propagation characteristics.

[0030] As shown in FIG. 5, the calculation unit 2 calculates the second propagation characteristic of the radio waves propagating from the transmission unit arranged at the first position C1 to the reception unit arranged at the third position C3 in the target area T where the new object B is arranged. When a radio wave is reflected by the object B and a reflected wave is generated, the calculation unit 2 calculates the second propagation characteristic with the influence of the reflected wave added.

[0031] As shown in FIG. 6, the calculation unit 2 sets a grid point group KG including three grid points Kr, Ks, and Kt corresponding to the shape of the reflection surface of the object B as the object B. The calculation unit 2 refers to, for example, the first calculation result of the first simulation and calculates the propagation path of the radio waves propagating from the first position C1 to the grid point Ks. The calculation unit 2 determines whether there is a propagation path of the reflected wave propagating to the grid point Ks among the propagation paths of the radio waves propagating to the grid point Ks.

[0032] As shown in FIG. 7, when there is a propagation path S6 of the reflected wave at the lattice point Ks, the calculation unit 2 calculates the reflection point or diffraction point R1 immediately before the reflected wave that propagates to the lattice point Ks in the propagation path S6. The calculation unit 2 determines whether the reflected wave reflected from the reflection point or diffraction point R1 is reflected by the object B and propagates to the receiving unit arranged at the third position C3. The calculation unit 2, for example, sets a partial element Bs of the object B corresponding to the lattice point Ks. The calculation unit 2 sets a mirror image position C3A of the third position C3 with respect to the partial element Bs. The mirror image position C3A is set to calculate the presence of the reflected wave that is reflected by the partial element Bs and propagates to the third position C3.

[0033] The calculation unit 2 calculates a virtual reflection region H2 where there is a reflected wave (radio wave) radiated from the reflection point or diffraction point R1. The virtual reflection region H2 is a virtual region that includes the partial element Bs among the reflected waves radiated along the propagation path S6 from the reflection point or diffraction point R1. Similarly, the calculation unit 2 calculates a virtual reflection region H1 where there is a radio wave radiated from the first position C1. The virtual reflection region H1 is a virtual region that includes the partial element Bs among the radio waves radiated along the propagation path S5 from the first position C1.

[0034] The calculation unit 2 determines whether the mirror image position C3A is included in the calculated virtual reflection regions H1 and H2. When the mirror image position C3A is included in the virtual reflection regions H1 and H2, the calculation unit 2 determines that the reflected wave reaches the receiving unit arranged at the third position C3. In the illustrated example, the mirror image position C3A is included in the virtual reflection region H1. The calculation unit 2, for example, in addition to the received power of the radio wave propagating along the propagation path S1 and the reflected wave propagating along the propagation path S2 (see FIG. 5) received by the receiving unit arranged at the third position C3, adds the received power of the reflected wave that propagates via the propagation path S5 and is reflected by the lattice point Ks, and calculates the second propagation characteristic of the radio wave at the third position C3.

[0035] The calculation unit 2 adds the influences of the reflected waves at each lattice point Kr, Ks, Kt included in the lattice point group KG, and calculates the second propagation characteristic of the radio wave at the third position C3. The calculation unit 2 adds the plurality of second propagation characteristics at the third position C3 obtained by adding the influences of the reflected waves at the plurality of lattice points Kr, Ks, Kt included in the lattice point group KG, and calculates the second propagation characteristic of the radio wave at the third position C3.

[0036] Based on the above processing, the calculation unit 2 refers to the first calculation result at the second position C2 in the state where an object is arranged at the second position C2 in the target area T, and calculates the reflected wave generated by the radio wave propagating to the object. When a reflected wave is generated by the radio wave reflecting from the object in the propagation path of the radio wave propagating to the object and the reflected wave reaches the receiving unit, the calculation unit 2 executes a second simulation that adds the reflected waves to calculate the second propagation characteristic. The calculation unit 2 outputs the second calculation result of the second simulation to the display unit 4.

[0037] FIG. 8 shows a method of calculating the influence when the existing object B is removed at the second position C2 between the transmission unit arranged at the first position C1 and the reception unit arranged at the third position C3 in the target area T. In the illustrated example, a propagation path S7 through which the reflected wave reflected by the reflecting surface T1 propagates to the receiving unit is shown. It is assumed that the propagation path S7 is calculated based on the second calculation result obtained by executing the second simulation in the state where the object B exists. Due to the presence of the object B, a part of the propagation path S8 of the radio wave propagating between the transmission unit and the reception unit is blocked.

[0038] In this state, the calculation unit 2 calculates the second propagation characteristic of the radio wave between the transmission unit and the reception unit that changes when the object B is removed. The calculation unit 2 refers to the second calculation result, and when the object is removed, determines whether the propagation path increases compared to the state before the object is removed. When the propagation path increases compared to the state before the object is removed, the calculation unit 2 adds the increased propagation path to calculate the second propagation characteristic.

[0039] As shown in FIG. 9, the calculation unit 2 sets a lattice point group KG including three lattice points Ku, Kv, and Kw corresponding to the shape of the reflecting surface of the object B as the object B. The calculation unit 2 calculates, for example, the propagation path of the radio wave propagating from the first position C1 to the lattice point Kv with reference to the first calculation result of the first simulation. The calculation unit 2 determines whether there is a propagation path of the radio wave propagating to the lattice point Kv among the propagation paths of the radio wave propagating to the lattice point Kv.

[0040] The calculation unit 2 sets a partial element Bs of the object B corresponding to the lattice point Kv. The calculation unit 2 determines whether the radio wave radiated from the first position C1 passes through the partial element Bs and propagates to the receiving unit arranged at the third position C3. The calculation unit 2 calculates a virtual reflection region H3 where the radio wave radiated from the first position C1 exists. The virtual reflection region H3 is a virtual region including the partial element Bs among the radio waves radiated along the propagation path S7 from the first position C1. The calculation unit 2 determines whether the third position C3 is included in the calculated virtual reflection region H3.

[0041] When the third position C3 is included in the virtual reflection region H3, the calculation unit 2 determines that the radio wave reaches the receiving unit arranged at the third position C3. In the illustrated example, the third position C3 is included in the virtual reflection region H3. The calculation unit 2 adds, for example, the received power of the radio wave propagating along the propagation path S8 in addition to the received power of the radio wave propagating along the propagation path S7 to the receiving unit arranged at the third position C3 due to the removal of the partial element Bs, and calculates the second propagation characteristic of the radio wave at the third position C3.

[0042] The calculation unit 2 determines whether there is a propagation path at each of the lattice points Ku, Kv, and Kw included in the lattice point group KG in order to calculate the change in the second propagation characteristic when the object B is removed, and calculates the second propagation characteristic of the radio wave that changes at the third position C3. The calculation unit 2 calculates the second propagation characteristic of the radio wave that changes at the third position C3 by adding the radio waves that increase at the third position C3 by calculating the propagation paths of the radio waves propagating to the plurality of lattice points Ku, Kv, and Kw included in the lattice point group KG.

[0043] The calculation unit may calculate the second propagation characteristic that changes for the moving object B. When the object B moves along a movement path along a predetermined direction, the calculation unit 2 calculates a plurality of second propagation characteristics considering the influence of a plurality of first simulation calculation results included in the lattice point group at the movement destination of the object B. The calculation unit 2 calculates the second propagation characteristic that changes based on the moving object based on the calculation results of the plurality of second propagation characteristics along the predetermined direction.

[0044] The calculation unit 2 may calculate the second propagation characteristic based on one or more of the reflection characteristic, diffraction characteristic, and transmission characteristic of the radio wave that changes based on the presence of the object. The reflection characteristic, diffraction characteristic, and transmission characteristic of the object are applied to the calculation process as parameters for factors that affect the propagation characteristic of the radio wave, such as the cross-sectional shape, surface shape, and material of the object. The calculation unit 2 adjusts each parameter according to the change in each characteristic and calculates the second propagation characteristic.

[0045] The calculation unit 2 corrects the first calculation result of the first simulation based on the following calculation method and calculates the second propagation characteristic of the radio wave when the reflected wave or radio wave increases at the third position C3. For example, in calculating the second propagation characteristic of the radio wave, the calculation unit 2 calculates the propagation delay and complex amplitude of a plurality of radio waves reaching the third position. The propagation delay is the delay amount that occurs at the timing when a plurality of radio waves reach the third position based on the difference in the path lengths of each propagation path. The calculation unit 2 calculates the complex amplitude of a plurality of radio waves based on the calculated propagation delay. The calculation unit 2 calculates the second propagation characteristic of the radio wave at the third position C3 by adding and subtracting the complex amplitudes given the propagation delay.

[0046] The calculation unit 2 calculates the propagation delay: τ” based on the following formula (4). τ” = τ i + l i ” / C (4) However, l i : The path length from the transmission unit or the reflection point to the lattice point l i ”: The extended path length from the lattice point to the third position τ i : Propagation time of radio wave to grid points C: Speed of light

[0047] The calculation unit 2 calculates the complex amplitude s of the radio wave that arrives while causing a propagation delay due to reflection, according to the following formula (5). i ” is calculated based on the following formula (5).

Equation

[0048] The calculation unit 2 calculates the complex amplitude of the radio wave newly generated by removing the object B based on the following formula (6).

Equation

[0049] The simulation executed in the simulation device 1 described above may be extended to the calculation of a three-dimensional communication area. The calculation unit 2 may execute simulations for a plurality of cross-sections of a three-dimensional target area in the horizontal plane direction and the vertical plane direction, and integrate the calculation results to calculate the second propagation characteristics in the three-dimensional communication area.

[0050] Fig. 10 shows the flow of processing of a simulation method for calculating the propagation characteristics of radio waves propagating from the transmitter to the receiver executed in the simulation device 1. The simulation method is executed based on a computer program installed in a computer mounted on the simulation device 1.

[0051] The calculation unit 2 calculates one or more propagation paths of radio waves that propagate from an arbitrary first position C1 in the target area T to a second position C2 different from the first position C1 (step S100). The calculation unit 2 calculates a first propagation characteristic of the radio waves received at the second position C2 based on the calculated propagation paths (step S102). The calculation unit 2 arranges the second position C2 at the positions of a plurality of grid points set in the target area T, and executes a first simulation for repeatedly calculating a plurality of first propagation characteristics (step S104). The calculation unit 2 stores the first calculation result of the first simulation in the storage unit 3 (step S106).

[0052] The calculation unit, within the target area, based on the arrangement relationship among the transmitter arranged at the first position, the object arranged at the second position, and the receiver arranged at an arbitrary third position, uses the previously calculated first calculation result to calculate the propagation path between the transmitter and the object based on the influence of the object (step S108). The calculation unit 2 adds the influence of the object, calculates the propagation path between the transmitter and the receiver, and executes a second simulation for calculating a second propagation characteristic based on the calculation result (step S110). The calculation unit 2 outputs the second calculation result of the second simulation to the display unit 4 (step S112).

[0053] As described above, according to the simulation device 1, by executing the first simulation for calculating the propagation characteristics of radio waves in the communication area in advance, it is possible to execute the second simulation for predicting the change in the propagation channel when the environment of the communication area changes and predict the change in the propagation channel. According to the simulation device 1, by executing the first simulation in advance, the calculation amount and calculation time when executing the second simulation can be significantly reduced, and it becomes possible to flexibly perform the performance evaluation of the wireless communication system in the actual communication area.

Explanation of Reference Numerals

[0054] 1 Simulation device, 2 Arithmetic unit, 3 Memory unit, 4 Display unit, 5 Input unit, B Object, Bs Sub-element, C1 First position, C2 Second position, C3 Third position, C3A Mirror image position, H1 Virtual reflection region, H2 Virtual reflection region, H3 Virtual reflection region, K Lattice point, KG Lattice point group, L Space, P Received power, R1 Reflection point or diffraction point, S1 Propagation path, T Target region, T1 Reflecting surface

Claims

1. In a target area where an object exists, it includes a calculation unit that calculates the propagation characteristics of the radio wave propagating between a transmission unit that radiates a radio wave and a reception unit that receives the radio wave. The calculation unit: Calculates one or more propagation paths of the radio wave propagating from an arbitrary first position in the target area to a second position different from the first position. Calculates a first propagation characteristic of the radio wave received at the second position based on the propagation path. Executes a first simulation in which the second position is arranged at the positions of a plurality of grid points set in the target area, and repeatedly calculates a plurality of the first propagation characteristics. Stores the first calculation result of the first simulation in a storage unit. A simulation device.

2. The calculation unit: In the target area, based on the arrangement relationship between the transmission unit arranged at the first position, the object arranged at the second position, and the reception unit arranged at an arbitrary third position, executes a second simulation that calculates a second propagation characteristic of the radio wave propagating between the transmission unit and the reception unit. In the second simulation, the calculation unit: Uses the first calculation result calculated in advance to calculate the propagation path between the transmission unit and the object based on the influence of the object. Adds the influence, calculates the propagation path between the transmission unit and the reception unit, and calculates the second propagation characteristic based on the calculation result. Outputs the second calculation result of the second simulation to a display unit. The simulation device according to Claim 1.

3. The calculation unit: Arranges the object in a grid point group including one or more grid points selected according to the shape of the object from among the plurality of grid points, and calculates a plurality of the second propagation characteristics. The simulation device according to Claim 2.

4. The calculation unit: In a state where the object is arranged at the second position, refers to the first calculation result at the second position. Calculates the shielding loss generated by the existence of the propagation path shielded by the object among the propagation paths, and calculates the second propagation characteristic based on the calculation result of the shielding loss. The simulation device according to Claim 3.

5. The calculation unit: In a state where the object is arranged at the second position, refers to the first calculation result at the second position. When the radio wave is reflected by the object in the propagation path to generate a reflected wave and the reflected wave reaches the receiving unit, the reflected waves are added to calculate the second propagation characteristic. The simulation apparatus according to claim 3.

6. The calculation unit Refers to the second calculation result, and when the object is removed, if the propagation path increases compared to the state before the object is removed, the increased propagation path is added to calculate the second propagation characteristic. The simulation apparatus according to claim 3.

7. The calculation unit Moves the lattice point group, calculates a plurality of the second propagation characteristics, Based on the plurality of the second propagation characteristics along a predetermined direction, calculates the second propagation characteristic based on the moving object. The simulation apparatus according to claim 3.

8. The calculation unit Calculates the second propagation characteristic based on one or more of the reflection characteristic, diffraction characteristic, and transmission characteristic of the radio wave that change based on the presence of the object. The simulation apparatus according to claim 2.

9. A program installed in a simulation apparatus for executing a simulation method of calculating a propagation characteristic of a radio wave that propagates between a transmission unit that radiates a radio wave and a reception unit that receives the radio wave in a target area where an object exists, causing a computer to Calculate one or more propagation paths of the radio wave that propagates from an arbitrary first position in the target area to a second position different from the first position, Calculate a first propagation characteristic of the radio wave received at the second position based on the propagation path, Execute a first simulation in which the second position is arranged at positions of a plurality of lattice points set in the target area and a plurality of the first propagation characteristics are repeatedly calculated, Store the first calculation result of the first simulation in a storage unit. Program.

10. Based on the arrangement relationship between the transmission unit arranged at the first position, the object arranged at the second position, and the reception unit arranged at an arbitrary third position in the target area, using the previously calculated first calculation result, calculate the propagation path between the transmission unit and the object based on the influence of the object, Add the influence, calculate the propagation path between the transmission unit and the reception unit, and execute a second simulation to calculate the second propagation characteristic of the radio wave that propagates between the transmission unit and the reception unit based on the calculation result. Causing the display unit to output the second calculation result of the second simulation The program according to claim 9

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