Reflective structure, wireless communication system, and method for installing reflective structure

Abstract

The purpose of the present disclosure is to provide a technique that makes it possible to reflect radio waves without installing a reflective structure in an inclined manner. A reflective structure according to the present disclosure comprises radio wave reflectors. The reflectors are repeatedly arranged one-dimensionally or two-dimensionally, and the reflectors respectively have radio wave reflection surfaces that are inclined in the same direction.

Description

Reflective structure, wireless communication system, and method for installing a reflective structure

[0001] The present disclosure relates to a reflective structure that reflects radio waves, a wireless communication system using the reflective structure, and a method for installing the reflective structure.

[0002] When there are blind areas where radio waves from the transmitter cannot reach directly due to buildings or topography, the visibility environment can be improved by installing reflective structures (also called reflectors) around such areas (see Non-Patent Document 1).

[0003] Tamami Maruyama, Tatsuo Furuno, Shinji Kamibayashi, "Study on Directional Control Reflectors to Eliminate Radio Wave Dead Zones," NTT DOCOMO Technical Journal, Vol. 17, No. 3, pp. 70-73, Oct. 2009.

[0004] In some cases, the reflecting structure itself is installed at an angle to reflect incoming radio waves, but the reflecting structure is often large, and installing it at an angle requires a large space.

[0005] In order to solve the above-mentioned problems, the present disclosure aims to provide a radio wave reflecting structure that does not need to be installed at an angle, a wireless communication system, and a method for installing a reflecting structure.

[0006] An aspect of the present disclosure is preferably a reflective structure comprising radio wave reflectors, the reflectors being repeatedly arranged one-dimensionally or two-dimensionally, and each of the reflectors having a radio wave reflecting surface inclined in the same direction.

[0007] The reflective structure of the present disclosure has reflectors arranged repeatedly one-dimensionally or two-dimensionally. Because the radio wave reflecting surfaces of the reflectors are inclined in the same direction, radio waves can be reflected without the need to install the reflective structure at an angle.

[0008] Fig. 1 is a configuration example of a wireless communication system using a reflective structure according to embodiment 1. Fig. 2 is a top view of the reflective structure according to embodiment 1. Fig. 3 is a side view of the reflective structure according to embodiment 1. Fig. 4 is a top view of a reflective structure according to a modified example of embodiment 1.

[0009] Embodiments of the present disclosure will be described with reference to the drawings. The same or corresponding components will be designated by the same reference numerals, and repeated description may be omitted.

[0010] 1 shows an example of the configuration of a wireless communication system 200 using a reflective structure 100 according to embodiment 1. The reflective structures 100 are installed in multiple locations, such as the top of a mountain 30, the rooftop and wall of a building 40, and roadside gutters. Radio waves 50 from a transmitter 10 are reflected by one or more reflective structures 100 and relayed to a receiver 20.

[0011] In the following, a case will be described in which the reflective structure 100 is provided as a cover (also called a grating) for a street gutter.

[0012] 2 and 3 are top views of the reflecting structure 100 according to the first embodiment. In a two-dimensional lattice-shaped frame 120 that functions as a cover for a gutter, a plate-shaped reflector 110 is provided in each gap formed by the lattice. The radio wave reflecting surfaces 111 of each reflector 110 are inclined in the same direction. As the radio wave reflecting surfaces 111 are inclined in the same direction, the reflecting structure 100 reflects the incoming radio waves 50 in one direction.

[0013] 2, the radio wave reflecting surface 111 faces between the direction in which it protrudes from the surface formed by the frame body 120 (Z direction) and the longitudinal direction of the surface (X direction). This is suitable for reflecting radio waves 50 arriving from directly above and in the longitudinal direction of the frame body 120, as well as from directions between these.

[0014] 3, the radio wave reflecting surface 111 faces between the direction in which it protrudes from the surface formed by the frame body 120 (Z direction) and the short side direction of the surface (Y direction), which is suitable for reflecting radio waves 50 arriving from directly above the frame body 120, the short side direction, and directions between these.

[0015] 4 is a side view of the reflecting structure 100 according to embodiment 1. Each radio wave reflecting surface 111 is inclined in the same direction and has a sawtooth shape in side view.

[0016] The inclination of the radio wave reflecting surface 111 is adjusted so that the radio wave 50 arriving from a specific direction is reflected in a desired direction. Specifically, the reflection direction can be adjusted by adjusting the inclination angle θ shown in FIG.

[0017] The specific direction is, for example, the direction from which the radio waves 50 arrive at the installation location. The desired direction is, for example, the direction of a blind zone where the radio waves 50 from the transmitter 10 have difficulty reaching directly. Alternatively, it may be the direction in which the receiver 20 is located. By reflecting the radio waves 50 in these directions, the visibility in the wireless communication system 200 is improved, and the blind zone can be eliminated.

[0018] When installing the reflecting structure 100, the worker determines the arrival direction of the radio waves 50 at the installation location by measuring RSSI or the like in advance. Furthermore, the worker installs the reflecting structure 100 so that the radio wave reflecting surface 111 of the reflector 110 faces the arrival direction of the radio waves 50. Alternatively, the worker installs the reflector 110 relative to a grating installed in a gutter. In this case, it is preferable to install the reflector 110 after adjusting the angle of the radio wave reflecting surface 111 so that the incoming radio waves 50 are reflected in the desired direction. Note that the installation method of the reflecting structure 100 is not limited to these methods.

[0019] As described above, in the reflecting structure 100 of the present disclosure, the reflectors 110 are arranged two-dimensionally and repeatedly. Since the radio wave reflecting surfaces 111 of the reflectors 110 are inclined in the same direction, the radio waves 50 can be reflected without tilting the reflecting structure 100 itself.

[0020] Furthermore, the reflective structure 100 of this embodiment can be provided in the form of a gutter cover. Generally, in order to newly install the reflective structure 100, it is necessary to secure an installation site, which entails the cost of the land and the installation work. By providing the gutter cover with the function of reflecting radio waves 50, it becomes unnecessary to secure an installation site. Furthermore, since the reflector 110 serves as a screen for the gutter, it is also effective from the viewpoint of environmental beautification. Furthermore, by providing a plurality of gutter covers with radio wave reflecting surfaces 111 oriented in different directions, as shown in FIGS. 2 and 3 , users can select and purchase a cover that is suitable for reflecting radio waves 50.

[0021] However, the reflective structure 100 of the present disclosure is not limited to being a gutter cover. The same effect as described above can be obtained by installing the reflective structure 100 on the top of a mountain 30, the roof or wall of a building 40, or the like.

[0022] The reflectors 110 may be repeatedly arranged in only one direction on a plane. The reflectors 110 do not necessarily have to be provided on the lattice-shaped frame 120. However, by arranging the reflectors 110 on the lattice-shaped frame 120, the strength of the reflective structure 100 can be increased.

[0023] <Modification> Fig. 5 is a top view of a reflective structure 100 according to a modification of the first embodiment. In a frame 120 having a one-dimensional lattice shape in a plan view, a reflector 110 for radio waves 50 is provided on the top surface of each lattice. The frame 120 functions as a cover for a gutter. The reflector 110 is, for example, a metal or dielectric plate, but is not limited thereto as long as it is made of a material and has a structure that can reflect radio waves 50. By tilting the radio wave reflecting surface 111 of each reflector 110 in the same direction, the same effect as that described in the first embodiment can be obtained.

[0024] The reflector 110 here includes a plurality of types of reflectors with different sizes of radio wave reflecting surface 111. This makes it possible to create a distribution of the reflectance of radio wave 50 within the surface of frame body 120.

[0025] The reflectors 110 may be arranged two-dimensionally and repeatedly on a plane. The radio wave reflecting surfaces 111 of the reflectors 110 do not necessarily have to be inclined in the same direction. By inclining the radio wave reflecting surfaces 111 of the reflectors 110 in different directions, the direction of the reflected radio waves 50 can be precisely controlled.

[0026] The present disclosure is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the present disclosure. Furthermore, the embodiments and modifications may be implemented in appropriate combinations, in which case the combined effects can be obtained.

[0027] 10: transmitter, 20: receiver, 30: mountain, 40: building, 50: radio wave, 100: reflective structure, 110: reflector, 111: radio wave reflective surface, 120: frame, 200: wireless communication system

Claims

1. A reflective structure comprising radio wave reflectors, which are repeatedly arranged one-dimensionally or two-dimensionally, and each of which has a radio wave reflecting surface that is inclined in the same direction.

2. A reflecting structure according to claim 1, further comprising a lattice-shaped frame, the reflectors being provided in the gaps formed by the lattices of the frame or on top of the lattices.

3. The reflecting structure according to claim 2, wherein the inclination of the radio wave reflecting surface is adjusted so that radio waves arriving from a specific direction are reflected in a desired direction.

4. The reflecting structure according to claim 3, wherein the frame is a cover for a street gutter.

5. The reflecting structure according to claim 4, wherein the reflector includes a plurality of types of reflectors with radio wave reflecting surfaces of different sizes.

6. A wireless communication system comprising a reflective structure according to any one of claims 1 to 5, a transmitter for transmitting the radio waves, and a receiver for receiving the radio waves, wherein the inclination of the radio wave reflecting surface of the reflector is adjusted so that the radio waves from the transmitter are reflected towards the receiver.

7. A method for installing a reflecting structure according to any one of claims 1 to 5, comprising installing the reflecting structure so that the radio wave reflecting surface faces the direction in which the radio waves arrive.

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