Radio wave relay system, structure, reflection region placement method, and reflection region placement program

Abstract

According to one embodiment of the present invention, provided is a radio wave relay system in which a plurality of reflection regions at differing positions each have a plurality of structures that reflect radio waves, wherein: in a first region, which is at the same height from the ground as a reception region that has been set in advance as a region where a wireless communication device should be able to receive radio waves, reflection regions that reflect radio waves in the horizontal direction toward the reception region are disposed in a greater number than reflection regions that reflect radio waves in other directions; and in a second region, which is at a different height from the ground compared to the reception region, reflection regions that reflect radio waves toward the reception region at a maximum reflection angle are disposed in a greater number than reflection regions that reflect radio waves in other directions.

Description

Radio wave relay system, structure, reflection area arrangement method, and reflection area arrangement program

[0001] The present invention relates to a radio wave relay system, a structure, a reflection area arrangement method, and a reflection area arrangement program.

[0002] In wireless communication systems, a technique for eliminating blind zones using a non-powered repeater (hereinafter referred to as a reflector) is known. By reflecting radio waves, the reflector may enable communication even with a terminal located outside the line of sight of the base station (see, for example, Non-Patent Document 1).

[0003] Tamami Maruyama and two others, "Research on Directional Reflectors to Eliminate Radio Wave Outage Areas," NTT DOCOMO Technical Journal, Vol. 17, No. 3, pp. 70-73, Oct. 2009.

[0004] However, for example, in a wireless communication system using high frequency, if a reflector only reflects regularly, the reflected waves may not reach the receiving device depending on the installation position of the reflector and the position of the receiving device, resulting in a dead zone. Furthermore, in the past, even if the reflector was directionally controllable, there were cases where it was not possible to obtain sufficient shielding properties for the receiving area that was previously set as the area where the wireless communication device should be able to receive radio waves.

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a radio wave relay system, a structure, a reflection area placement method, and a reflection area placement program that enable radio waves to be efficiently reflected to a reception area that has been preset as an area in which a wireless communication device should be able to receive radio waves.

[0006] A radio wave relay system according to one embodiment of the present invention is a radio wave relay system having a plurality of structures in which a plurality of reflective areas at different positions each reflect radio waves, and is characterized in that in a first area which is at the same height from the ground surface as a receiving area which has been preset as an area in which a wireless communication device should be able to receive radio waves, the reflective areas which reflect radio waves horizontally toward the receiving area are arranged so that there are more of them than the reflective areas which reflect radio waves in other directions, and in a second area which is at a different height from the ground surface than the receiving area, the reflective areas which reflect radio waves at the maximum reflection angle toward the receiving area are arranged so that there are more of them than the reflective areas which reflect radio waves in other directions.

[0007] Furthermore, a structure according to one embodiment of the present invention is a structure in which multiple reflective areas at different positions each reflect radio waves, and in a first area which is at the same height from the ground surface as a receiving area which has been preset as an area in which a wireless communication device should be able to receive radio waves, the reflective areas which reflect radio waves horizontally toward the receiving area are arranged so that there are more of them than the reflective areas which reflect radio waves in other directions, and in a second area which is at a different height from the ground surface than the receiving area, the reflective areas which reflect radio waves at the maximum angle toward the receiving area are arranged so that there are more of them than the reflective areas which reflect radio waves in other directions.

[0008] Furthermore, a reflection area placement method according to one embodiment of the present invention is a reflection area placement method for placing a plurality of reflection areas, each of which reflects radio waves, on a structure, and is characterized by including a first step of placing, in a first area that is the same height from the ground surface as a reception area that has been preset as an area in which a wireless communication device should be able to receive radio waves, the reflection areas that reflect radio waves horizontally toward the reception area so that they are more numerous than the reflection areas that reflect radio waves in other directions, and a second step of placing, in a second area that is a different height from the ground surface than the reception area, the reflection areas that reflect radio waves toward the reception area at the maximum reflection angle so that they are more numerous than the reflection areas that reflect radio waves in other directions.

[0009] Furthermore, a reflection area placement program according to one embodiment of the present invention is a reflection area placement program that causes a computer to execute a process for determining the placement of a plurality of reflection areas, each of which reflects radio waves, on a structure, and that causes the computer to execute the following steps: a first step of placing a first area, which is at the same height from the ground surface as a reception area that has been preset as an area in which a wireless communication device should be able to receive radio waves, so that the number of reflection areas that reflect radio waves horizontally toward the reception area is greater than the number of reflection areas that reflect radio waves in other directions; and a second step of placing a second area, which is at a different height from the ground surface than the reception area, so that the number of reflection areas that reflect radio waves toward the reception area at the maximum reflection angle is greater than the number of reflection areas that reflect radio waves in other directions.

[0010] According to the present invention, it is possible to efficiently reflect radio waves to a reception area that is set in advance as an area where a radio communication device should be able to receive radio waves.

[0011] FIG. 1 is a schematic diagram showing a configuration example of a radio wave relay system according to an embodiment as viewed from the front and the side; FIG. 2 is a diagram showing a configuration example of a radio wave relay system according to an embodiment as viewed from the front; FIG. 3 is a diagram showing a configuration example of a radio wave relay system according to an embodiment as viewed from the side; FIG. 4 is a flowchart showing a reflective area arrangement method for arranging a plurality of reflectors that each reflect radio waves on a structure; FIG. 5 is a diagram showing a schematic overview of a radio wave relay system of a comparative example as viewed from above; FIG. 6 is a diagram showing a schematic example of an overview of a radio wave relay system according to an embodiment as viewed from above.

[0012] Before describing the radio wave relay system according to one embodiment, the background to the invention will be described. Fig. 5 is a diagram schematically illustrating an outline of a radio wave relay system of a comparative example, viewed from above.

[0013] 5, for example, base station 1 is placed on the roof of structure 2 such as a building. Also, assume that user A, who has a terminal that performs wireless communication with base station 1, is located between structure 2 and structure (such as a building) 3.

[0014] The high frequency radio waves transmitted from base station 1 may be blocked by a vehicle 4 passing between structure 2 and structure 3, and may not reach the terminal carried by user A. Furthermore, even if reflectors 5 and 6 are provided on structure 3, if reflectors 5 and 6 only provide regular reflection, the radio waves may not reach the terminal carried by user A.

[0015] Therefore, a radio wave relay system according to one embodiment is configured to enable radio waves to be efficiently reflected to a reception area that is set in advance as an area where radio waves should be receivable by a wireless communication device.

[0016] Figure 6 is a diagram illustrating a schematic overview of a radio wave relay system according to one embodiment, viewed from above. In Figure 6, components that are substantially the same as those shown in Figure 5 are assigned the same reference numerals. Reflectors 7 and 8 are provided on the structure 3 and are configured to provide irregular reflection, efficiently reflecting radio waves toward the receiving area. Therefore, even if the radio waves transmitted by the base station 1 are blocked by a vehicle 4, the radio waves can still reach the terminal carried by user A.

[0017] Here, each of the reflectors 7 and 8 may be configured with a plurality of independent reflectors. In this case, the independent reflectors form reflecting areas with different reflecting directions. Alternatively, each of the reflectors 7 and 8 may be configured as a single reflector having a plurality of reflecting areas with different reflecting directions.

[0018] Next, a radio wave relay system 10 according to an embodiment will be described in detail with reference to Figures 1 to 3. Figure 1 is a schematic diagram showing a configuration example of the radio wave relay system 10 according to an embodiment as viewed from the front and side. Figure 2 is a diagram showing a configuration example of the radio wave relay system 10 according to an embodiment as viewed from the front. Figure 3 is a diagram showing a configuration example of the radio wave relay system 10 according to an embodiment as viewed from the side.

[0019] The radio wave relay system 10 has a structure 20, such as one or more buildings, built on the ground. A reception area (a region of three-dimensional space surrounded by a dashed line in FIG. 1 ) is set in advance near the ground surface of the structure 20 as an area where a wireless communication device should be able to receive radio waves. In general, it is considered that the vertical or horizontal width (m) of the reception area in three-dimensional space on the ground surface is greater than the height (m) from the ground surface.

[0020] The structure 20 has a plurality of reflectors 30 at different positions on its surface at least in the vertical direction. The reflectors 30 form individual reflecting areas, each with a set reflection direction. The plurality of reflectors 30 may also be configured as a single reflector having a plurality of reflecting areas with different reflection directions. Note that a portion of the reflectors (reflecting areas) 30 may be a reflector that regularly reflects radio waves.

[0021] In the first area 100, which is at the same height from the ground as the receiving area, the number of reflectors 30 that reflect radio waves in the horizontal direction toward the receiving area is arranged so that it is greater than the number of reflectors 30 that reflect radio waves in other directions.

[0022] For example, the multiple reflectors 30 arranged at the same height as the receiving area are arranged so that the maximum number of reflectors is set to reflect radio waves transmitted from a base station (not shown) in a substantially horizontal direction.

[0023] In addition, in a second area 200 having a different height from the ground surface than the receiving area, the number of reflectors 30 that reflect radio waves toward the receiving area at the maximum reflection angle is arranged so that it is greater than the number of reflectors 30 that reflect radio waves in other directions.

[0024] For example, the reflectors 30 are arranged at a height different from the receiving area so that the maximum number of reflectors 30 is set so that the direction of reflection of radio waves is almost vertical toward the receiving area.

[0025] Next, a method for arranging a plurality of reflectors (reflection areas) 30, each of which reflects radio waves, on the structure 20 will be described.

[0026] FIG. 4 is a flowchart showing a reflection area arrangement method for arranging a plurality of reflectors 30, each of which reflects radio waves, on the structure 20.

[0027] As shown in Figure 4, in the reflection area placement method, first, in the first step, in a first area 100 that is at the same height from the ground as the receiving area, reflectors 30 that reflect radio waves horizontally toward the receiving area are placed so that the number of reflectors 30 that reflect radio waves in the horizontal direction toward the receiving area is greater than the number of reflectors 30 that reflect radio waves in other directions (S100).

[0028] Next, in the second step, in the second area 200, which is at a different height from the ground surface than the receiving area, the reflectors 30 that reflect radio waves toward the receiving area at the maximum angle are arranged so that the number of reflectors 30 that reflect radio waves in other directions is greater than the number of reflectors 30 that reflect radio waves in other directions (S102).

[0029] Furthermore, the reflection area arrangement method (processing for determining the arrangement) shown in Fig. 4 may be executed by a computer. For example, a reflection area arrangement program causes a computer including a CPU and a memory to execute the first and second steps described above.

[0030] In this way, the radio wave relay system 10 can reflect radio waves in different directions depending on the height relative to the receiving area, concentrating the reflected waves in the receiving area and efficiently reflecting radio waves to the receiving area. In other words, the radio wave relay system 10 increases the propagation paths to the receiving device, improving shielding resistance and increasing received power.

[0031] REFERENCE SIGNS LIST 1... base station, 2, 3... structure, 4... vehicle, 7, 8... reflector, 10... radio wave relay system, 20... structure, 30... reflector, 100... first area, 200... second area

Claims

1. A radio wave relay system having a plurality of structures with a plurality of reflective areas at different positions that each reflect radio waves, wherein in a first area that is the same height from the ground as a predetermined receiving area in which radio waves should be able to be received by a wireless communication device, the reflective areas that reflect radio waves horizontally toward the receiving area are arranged so that there are more of them than there are of them that reflect radio waves in other directions, and in a second area that is a different height from the ground than the receiving area, the reflective areas that reflect radio waves toward the receiving area at the maximum reflection angle are arranged so that there are more of them than there are of them that reflect radio waves in other directions.

2. The radio wave relay system according to claim 1, characterized in that the reflective areas are each individual reflectors.

3. A radio wave relay system as described in claim 1 or 2, characterized in that a part of the reflective area is a reflector that regularly reflects radio waves.

4. A structure in which multiple reflective areas at different positions each reflect radio waves, wherein in a first area that is the same height from the ground as a predetermined receiving area in which a wireless communication device should be able to receive radio waves, the reflective areas that reflect radio waves horizontally toward the receiving area are arranged so that they are more numerous than the reflective areas that reflect radio waves in other directions, and in a second area that is a different height from the ground than the receiving area, the reflective areas that reflect radio waves toward the receiving area at the maximum angle of reflection are arranged so that they are more numerous than the reflective areas that reflect radio waves in other directions.

5. The structure of claim 4, wherein each of the reflective areas is an individual reflector.

6. A structure as claimed in claim 4 or 5, characterized in that a part of the reflective area is a reflector that regularly reflects radio waves.

7. A method for arranging a plurality of reflective areas, each of which reflects radio waves, on a structure, comprising: a first step of arranging, in a first area that is the same height from the ground surface as a predetermined receiving area in which a wireless communication device should be able to receive radio waves, the number of reflective areas that reflect radio waves horizontally toward the receiving area so that the number of reflective areas that reflect radio waves in other directions is greater than the number of reflective areas that reflect radio waves in other directions, in a second area that is a different height from the ground surface than the receiving area, so that the number of reflective areas that reflect radio waves toward the receiving area at the maximum reflection angle is greater than the number of reflective areas that reflect radio waves in other directions.

8. A reflective area placement program that causes a computer to execute a process for determining the placement of multiple reflective areas, each of which reflects radio waves, on a structure, comprising: a first step of placing, in a first area that is the same height from the ground as a predetermined receiving area in which a wireless communication device should be able to receive radio waves, the reflective areas that reflect radio waves horizontally toward the receiving area so that they are more numerous than the reflective areas that reflect radio waves in other directions; and a second step of placing, in a second area that is a different height from the ground than the receiving area, the reflective areas that reflect radio waves toward the receiving area at the maximum angle so that they are more numerous than the reflective areas that reflect radio waves in other directions.

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