Location determination system, location determination device, location determination method, and location determination program

Abstract

A station placement determination system according to one embodiment has: a ray tracing unit for performing ray tracing from a transmission point for a region including an RIS station placement candidate region comprising a set of small regions obtained by subdividing the region into a plurality; a first calculation unit for calculating, on the basis of the ray tracing results, a propagation path power and a reflection point position for each propagation path along which an electromagnetic wave is propagated from the transmission point to a reception region by line of sight after being reflected one time within the station placement candidate region; a station placement region determination unit for determining the small region including the most reflection point positions to be an RIS station placement region; a second calculation unit for calculating, for the station placement region, a propagation path incidence angle having the maximum propagation path power calculated by the first calculation unit and a reflection angle to the reception region from a centroid based on the reflection point positions; and an output unit that outputs the station placement region and each of values indicating the incidence angle and the reflection angle.

Description

Technical Field

[0001] The present invention relates to a location determination system, a location determination device, a location determination method, and a location determination program.

Background Art

[0002] In order to achieve high-speed and large-capacity wireless access, attention has been paid to utilizing high-frequency bands that can secure a wide bandwidth. For example, in the fifth-generation mobile communication system, the 28 GHz band is used, and in the IEEE 802.11ad (millimeter-wave wireless LAN system), which is a wireless LAN standard, the 60 GHz band is used to achieve high-speed and large-capacity.

[0003] Radio waves in high-frequency bands are more likely to attenuate and are less diffractive than those in low-frequency bands. Therefore, when utilizing high-frequency bands, there are problems such as short transmission distances and significant deterioration of reception quality due to shielding.

[0004] For example, in order to relay electromagnetic waves to a receiving point that is blocked in sight from a transmitting point, there is a repeater device called a RIS (Reconfigurable Intelligent Surface) reflector that can electrically change element characteristics and dynamically control the reflection characteristics of electromagnetic waves.

[0005] Also, a method for calculating the location of a radio base station that relays electromagnetic waves is known (see, for example, Non-Patent Document 1).

Prior Art Documents

Non-Patent Documents

[0006]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] To enhance the effectiveness of repeaters such as RIS reflectors, it is necessary to place the RIS reflectors in a location where they can receive sufficient power from the transmitting station.

[0008] However, conventional technology could only calculate the location of wireless base stations that emit radio waves themselves, and it was difficult to calculate and determine the appropriate location for repeaters such as RIS reflectors.

[0009] The present invention has been made in view of the above-mentioned problems, and aims to provide a location determination system, location determination device, location determination method, and location determination program that can determine a suitable location for an RIS reflector that does not emit electromagnetic waves itself in order to increase the relay power. [Means for solving the problem]

[0010] A location determination system according to one aspect of the present invention, in a case where electromagnetic waves transmitted from a transmission point are relayed by reflection to a receiving point within a line-of-sight shielded receiving area, the location determination system determines the location of an RIS reflector, comprising: a ray tracing unit that performs ray tracing from the transmission point to a region including a candidate location area of ​​the RIS reflector, which consists of a collection of subdivided small regions; and a propagation path for each propagation path that propagates the electromagnetic waves from the transmission point to the receiving area in line of sight after one reflection within the candidate location area, based on the ray tracing results performed by the ray tracing unit. The system is characterized by comprising: a first calculation unit that calculates propagation power and reflection point positions; a location area determination unit that determines the small region containing the most reflection point positions calculated by the first calculation unit as the location area of ​​the RIS reflector; a second calculation unit that calculates, for the location area determined by the location area determination unit, the incidence angle of the propagation path with the maximum propagation path power calculated by the first calculation unit, and the reflection angle from the centroid based on the reflection point positions calculated by the first calculation unit to the receiving area; and an output unit that outputs the location area determined by the location area determination unit, as well as values ​​indicating the incidence angle and reflection angle calculated by the second calculation unit.

[0011] Furthermore, in a location determination device according to one aspect of the present invention, when electromagnetic waves transmitted from a transmitting point are relayed by reflection to a receiving point within a receiving area shielded by line of sight, the location determination device for determining the location of an RIS reflector calculates the propagation path power and reflection point position for each propagation path that propagates electromagnetic waves from the transmitting point to the receiving area in line of sight after one reflection within the candidate location area, based on the ray tracing results obtained by performing ray tracing from the transmitting point to an area including a candidate location area of ​​an RIS reflector which consists of a collection of multiple subdivided small areas. The system is characterized by comprising: a first calculation unit; a location area determination unit that determines the small region containing the most reflection point positions calculated by the first calculation unit as the location area of ​​the RIS reflector; a second calculation unit that calculates, for the location area determined by the location area determination unit, the incidence angle of the propagation path with the maximum propagation path power calculated by the first calculation unit, and the reflection angle from the centroid based on the reflection point positions calculated by the first calculation unit to the receiving area; and an output unit that outputs the location area determined by the location area determination unit, as well as values ​​indicating the incidence angle and reflection angle calculated by the second calculation unit.

[0012] Furthermore, in a location determination method according to one aspect of the present invention, when electromagnetic waves transmitted from a transmitting point are relayed by reflection to a receiving point within a line-of-sight shielded receiving area, the location determination method for determining the location of an RIS reflector includes a ray tracing step of performing ray tracing from the transmitting point on an area including a candidate location area for the RIS reflector, which consists of a collection of subdivided small areas, and based on the ray tracing results performed in the ray tracing step, determining the propagation path power and reflection point position of each propagation path that propagates the electromagnetic waves from the transmitting point to the receiving area in line of sight after one reflection within the candidate location area. The system is characterized by including: a first calculation step for calculating the location; a location area determination step for determining the small region containing the most reflection point locations calculated in the first calculation step as the location area of ​​the RIS reflector; a second calculation step for calculating, for the location area determined in the location area determination step, the incidence angle of the propagation path that maximizes the propagation path power calculated in the first calculation step, and the reflection angle from the centroid based on the reflection point locations calculated in the first calculation step to the receiving area; and an output step for outputting the location area determined in the location area determination step, as well as values ​​indicating the incidence angle and reflection angle calculated in the second calculation step. [Effects of the Invention]

[0013] According to the present invention, it is possible to determine an optimal placement location for an RIS reflector that does not emit electromagnetic waves itself, in order to increase the relayed power. [Brief explanation of the drawing]

[0014] [Figure 1] This diagram schematically shows the environment in which the placement position of an RIS reflector should be determined by a placement determination system according to one embodiment. [Figure 2] This figure schematically shows the wall surface in the environment shown in Figure 1. [Figure 3] This figure shows an example configuration of a location determination system according to one embodiment. [Figure 4] This flowchart shows an example of the operation of a location determination system according to one embodiment. [Figure 5] It is a diagram showing an example of the hardware configuration of a placement determination device according to an embodiment.

Mode for Carrying Out the Invention

[0015] When explaining a placement determination system according to an embodiment, first, the environment that is the target for which the placement position of the RIS reflector is to be determined by the placement determination system will be described using FIGS. 1 and 2.

[0016] FIG. 1 is a diagram schematically showing an environment that is the target for which the placement position of the RIS reflector is to be determined by a placement determination system according to an embodiment. FIG. 2 is a diagram schematically showing the wall surface 100 in the environment shown in FIG. 1.

[0017] Note that the RIS reflector for which the placement (position) is to be determined is assumed to be a repeater for relaying the electromagnetic wave transmitted from the transmission point to the reception point in the reception area that is blocked in direct view by reflection. However, when using the placement determination system, the reception area does not necessarily have to be blocked in direct view from the transmission point.

[0018] As shown in FIG. 1, in the environment that is the target for which the placement position of the RIS reflector is to be determined, a plurality of shielding objects W such as walls are arranged. The transmission point Tx where the transmission device for transmitting electromagnetic waves (radio waves) is arranged and the reception area Rx where the reception device receives the electromagnetic waves are blocked by the shielding object W in direct view.

[0019] Also, the wall surface 100 is a structure on which the RIS reflector can be installed. As also shown in FIG. 2, the wall surface 100 is composed of, for example, a set of a plurality of small regions S subdivided in a square lattice pattern (3 in the vertical direction and 11 in the horizontal direction), and includes a placement candidate area A for the RIS reflector and a non-placement candidate area B for the RIS reflector.

[0020] The placement candidate area A for the RIS reflector is an area that can form a propagation path for propagating the electromagnetic wave to the reception area Rx in direct view after one reflection within the placement candidate area A from the transmission point Tx, as exemplified in FIG. 1.

[0021] Next, a specific configuration example of the station placement determination system 1 according to an embodiment will be described. FIG. 3 is a diagram showing a configuration example of the station placement determination system 1 according to an embodiment. As shown in FIG. 3, the station placement determination system 1 includes, for example, a ray tracing unit 2 and a station placement determination device 3.

[0022] The ray tracing unit 2 performs ray tracing from the transmission point Tx on the area including the station placement candidate area A of the wall surface 100 (FIG. 1), and outputs the result of the ray tracing to the station placement determination device 3.

[0023] The station placement determination device 3 includes, for example, a storage unit 31, a first calculation unit 32, a station placement area determination unit 33, a second calculation unit 34, and an output unit 35.

[0024] The storage unit 31 is a storage device having, for example, a result storage unit 311, a candidate area storage unit 312, and a reception area storage unit 313.

[0025] The result storage unit 311 stores the result of the ray tracing executed by the ray tracing unit 2. The candidate area storage unit 312 stores information indicating the position of each small area S of the wall surface 100, information indicating the position (range) of the station placement candidate area A, and the like. The reception area storage unit 313 stores information indicating the position (range) of the reception area Rx and the like.

[0026] The first calculation unit 32 accesses the storage unit 31, and based on the ray tracing result executed by the ray tracing unit 2, calculates the propagation path power and the reflection point position of each propagation path that propagates electromagnetic waves from the transmission point Tx to the reception area Rx in a straight line after one reflection within the station placement candidate area A, and outputs the calculated results to the station placement area determination unit 33 and the second calculation unit 34.

[0027] The station placement area determination unit 33 accesses the storage unit 31, determines the small area S that most includes the reflection point positions calculated by the first calculation unit 32 as the station placement area C (see FIG. 2) of the RIS reflector, and outputs the determined result to the second calculation unit 34 and the output unit 35.

[0028] The second calculation unit 34 calculates, for the location area C determined by the location area determination unit 33, the incident angle of the propagation path where the propagation path power calculated by the first calculation unit 32 is maximum, and the reflection angle from the centroid based on the reflection point position calculated by the first calculation unit 32 to the receiving area Rx, and outputs the calculated results to the output unit 35.

[0029] Furthermore, the second calculation unit 34 may calculate the reflection angle to the centroid of the receiving region Rx, or the reflection angle to any receiving point within the receiving region Rx. Here, the second calculation unit 34 uses, for example, the geometric center, or a geometric center weighted according to the propagation path power, as the centroid.

[0030] For example, the second calculation unit 34 sets the lower left of the small region S as the origin and the length of one side of the small region S as a, and calculates the centroid of the small region S, which has become the local area C, as (a / 2, a / 2) (see Figure 2).

[0031] The output unit 35 outputs the location area determined by the location area determination unit 33, as well as the values ​​indicating the incident angle and reflection angle calculated by the second calculation unit 34.

[0032] Next, an example of the operation of the location determination system 1 will be described. Figure 4 is a flowchart of an example of the operation of the location determination system 1 according to one embodiment. As shown in Figure 4, the location determination system 1 calculates the propagation path power and reflection point position from the transmission point Tx to the receiving area Rx (receiving point) by ray tracing (S100).

[0033] Next, the station location determination system 1 selects a small region S containing the most reflection point locations from among the candidate station location regions A that have a line of sight to the receiving region Rx (receiving point) as the station location region C for the RIS reflector (S102).

[0034] Subsequently, the station location determination system 1 calculates the incidence angle of the propagation path with the maximum propagation path power for the station location area C, and the reflection angle from the centroid based on the reflection point position to the receiving area Rx (S104).

[0035] The location determination system 1 then outputs values ​​indicating the location area, the angle of incidence, and the angle of reflection (S106).

[0036] Thus, the station location determination system 1 determines the small region S containing the most reflection point locations as the station location region C for the RIS reflector. For the station location region C, it calculates the incidence angle of the propagation path that maximizes the propagation path power and the reflection angle from the centroid based on the reflection point locations to the receiving region. Therefore, it can determine a suitable station location for the RIS reflector, which does not emit electromagnetic waves itself, in order to increase the relay power.

[0037] In other words, the station location determination system 1 can maximize the incoming power to the RIS reflector and maximize the relay power to the receiving point.

[0038] Furthermore, each function of the station location determination device 3 may be partially or entirely composed of hardware such as a PLD (Programmable Logic Device) or FPGA (Field Programmable Gate Array), or it may be composed of a program executed by a processor such as a CPU.

[0039] For example, the location determination device 3 according to the present invention can be implemented using a computer and a program, and the program can be recorded on a storage medium or provided via a network.

[0040] Figure 5 shows an example of the hardware configuration of a location determination device 3 according to one embodiment. As shown in Figure 5, for example, the location determination device 3 has an input unit 50, an output unit 51, a communication unit 52, a CPU 53, a memory 54, and an HDD 55 connected via a bus 56, and is equipped with computer functions. The location determination device 3 is also configured to be able to input and output data to and from a computer-readable storage medium 57.

[0041] The input unit 50 is, for example, a keyboard and mouse. The output unit 51 is, for example, a display device such as a display, and corresponds to the output unit 35 described above. The communication unit 52 is a wired or wireless network interface.

[0042] The CPU 53 controls each component of the location determination device 3 and performs predetermined processing. The memory 54 and HDD 55 are storage units that store data, etc., and correspond to the storage unit 31 described above.

[0043] The storage medium 57 is capable of storing programs and the like that which cause the location determination device 3 to perform its functions. Note that the architecture of the location determination device 3 is not limited to the example shown in Figure 5.

[0044] Here, "computer" includes hardware such as the operating system and peripheral devices. Furthermore, "computer-readable storage medium" refers to storage devices such as flexible disks, magneto-optical disks, ROMs, CD-ROMs, and other portable media.

[0045] Furthermore, "computer-readable storage medium" may include devices that dynamically hold programs for a short period of time, such as communication lines used when transmitting programs over networks such as the Internet or communication lines such as telephone lines, as well as devices that hold programs for a certain period of time, such as volatile memory inside computers that act as servers or clients in such cases.

[0046] While embodiments of the present invention have been described above with reference to the drawings, it is clear that the above-described embodiments are merely illustrative examples of the present invention, and the present invention is not limited to the above-described embodiments. Therefore, additions, omissions, substitutions, and other modifications of components may be made without departing from the technical concept and scope of the present invention. [Explanation of Symbols]

[0047] 1...Location determination system, 2...Ray tracing unit, 3...Location determination device, 31...Storage unit, 32...First calculation unit, 33...Location area determination unit, 34...Second calculation unit, 35...Output unit, 50...Input unit, 51...Output unit, 52...Communication unit, 53...CPU, 54...Memory, 55...HDD, 56...Bus, 57...Storage medium, 100...Wall surface, 311...Result storage unit, 312...Candidate area storage unit, 313...Received area storage unit

Claims

1. In a system for determining the placement of RIS reflectors when electromagnetic waves transmitted from a transmission point are relayed by reflection to a receiving point within a receiving area shielded by line of sight, A ray tracing unit performs ray tracing from the transmission point on a region that includes a candidate area for the placement of a RIS reflector, which consists of a collection of subdivided sub-regions, A first calculation unit calculates the propagation path power and reflection point position for each propagation path that propagates electromagnetic waves from the transmission point to the reception area in line of sight after one reflection within the candidate station area, based on the ray tracing results performed by the ray tracing unit, A location area determination unit determines the small region containing the most reflection point positions calculated by the first calculation unit as the location area of ​​the RIS reflector, A second calculation unit calculates, with respect to the location area determined by the location area determination unit, the incidence angle of the propagation path where the propagation path power calculated by the first calculation unit is maximum, and the reflection angle from the centroid based on the reflection point position calculated by the first calculation unit to the receiving area. An output unit that outputs the location area determined by the location area determination unit, and the values ​​indicating the incident angle and reflection angle calculated by the second calculation unit. A location determination system characterized by having the following features.

2. The second calculation unit is, Calculating the angle of reflection to the centroid of the receiving area, or to any receiving point within the receiving area. The location determination system according to claim 1, characterized by the following:

3. The second calculation unit is, The centroid is the geometric center, or a geometric center weighted according to the propagation path power. A location determination system according to claim 1 or 2, characterized by the above.

4. In a case where electromagnetic waves transmitted from a transmission point are relayed by reflection to a receiving point within a receiving area shielded by line of sight, a location determination device for determining the location of a RIS reflector, A first calculation unit calculates the propagation path power and reflection point position for each propagation path that propagates electromagnetic waves from the transmission point to the receiving area in line of sight after one reflection within the candidate area, based on the ray tracing results obtained by performing ray tracing from the transmission point on an area including a candidate area for the placement of a RIS reflector, which is a collection of multiple subdivided sub-regions. A location area determination unit determines the small region containing the most reflection point positions calculated by the first calculation unit as the location area of ​​the RIS reflector, A second calculation unit calculates, with respect to the location area determined by the location area determination unit, the incidence angle of the propagation path where the propagation path power calculated by the first calculation unit is maximum, and the reflection angle from the centroid based on the reflection point position calculated by the first calculation unit to the receiving area. An output unit that outputs the location area determined by the location area determination unit, and the values ​​indicating the incident angle and reflection angle calculated by the second calculation unit. A location determination device characterized by having the following features.

5. The second calculation unit is, Calculating the angle of reflection to the centroid of the receiving area, or to any receiving point within the receiving area. The location determination device according to claim 4, characterized by the following:

6. The second calculation unit is, The centroid is the geometric center, or a geometric center weighted according to the propagation path power. A location determination device according to claim 4 or 5, characterized by the above.

7. In a method for determining the placement of an RIS reflector when electromagnetic waves transmitted from a transmission point are relayed by reflection to a receiving point within a receiving area shielded by line of sight, A ray tracing step is performed on a region that includes a candidate area for the placement of a RIS reflector, which consists of a collection of subdivided sub-regions, from the transmission point. A first calculation step calculates the propagation path power and reflection point position for each propagation path that propagates electromagnetic waves from the transmission point to the reception area in line of sight after one reflection within the candidate station area, based on the ray tracing results performed by the ray tracing step described above. A location area determination step in which the small region containing the most reflection point positions calculated in the first calculation step is determined as the location area of ​​the RIS reflector, A second calculation step is performed to calculate, with respect to the station location area determined by the station location area determination step, the incident angle of the propagation path that maximizes the propagation path power calculated in the first calculation step, and the reflection angle from the centroid based on the reflection point position calculated in the first calculation step to the receiving area. An output step that outputs the location area determined by the location area determination step, and the values ​​indicating the angle of incidence and the angle of reflection calculated by the second calculation step. A method for determining a location, characterized by including the following:

8. A location determination program for causing a computer to function as a component of the location determination device described in claim 4 or 5.

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