JP2011029992A - Bidirectional radio connection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bidirectional radio connection system for performing a bidirectional radio connection via a wall or the like. <P>SOLUTION: The bidirectional radio connection system includes: a first antenna assembly 100 which is installed in a wall-back space (BAS) 8 of a wall 10 and includes a large-aperture horn type reflector and a first antenna for collecting radio waves transmitted through the wall 10; a second antenna assembly 200 composed of a second antenna and a reflection plate to which an output of the first antenna is directly connected via a line; a wall-back space transmitting/receiving station 300 which is disposed in the wall-back space (BAS) 8, includes a third antenna and operates at a first carrier frequency (f1); and an amplification and connection means 4, 5, 6 for amplifying and connecting a receiving output of the second antenna to the first antenna. A wall-front space transmitting/receiving station 500 and the wall-back space transmitting/receiving station 300 are bidirectionally radio-connected via the wall 10. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a bidirectional wireless connection system in two spaces (for example, indoor and outdoor) separated by a concrete wall or the like in an area in a city covered by the latest wireless communication network such as Wi-Fi.
More specifically, the bidirectional wireless connection system according to the present invention relates to a bidirectional wireless connection system using a part of the concrete wall or the like as a part of a communication path.

In urban areas covered by the latest wireless communication networks such as Wi-Fi, the network in the building and the network outside the building are connected via an antenna installed on the rooftop. That is, normally, a concrete wall of a building is treated as a reflector / scatterer, and a communication path is designed (Non-Patent Documents 1 and 2). The loss of the wall is treated as large, and wireless connection using radio waves that have passed through the wall has not been considered.
The antenna device described in Patent Document 1 proposes an antenna device that receives signals in one space and amplifies them in the other space and emits them as radio waves in a space divided by walls or walls that are not suitable for passing radio waves. .
In the invention described in Patent Document 2, a hole is made in a wall to enable communication between antennas in both spaces.

  If it can be wirelessly connected through a concrete wall, there is no need to install an antenna on the roof, which is very convenient.

JP-A-8-331028 JP 2007-270459 A

Amir Adler and Moshe Salhov, "A Carrier-Grade Wireless LAN Network Implementation", IEEE Microwave Magazine, Vol.9, No.4, pp.108-119, August 2008. Simon R. Saunders, "Antennas and Propagation for Wireless Communication Systems", Chapter 1 Introduction, pp.7-8 and Chapter 13 Picocells, pp.272-273, John Wiely & Sons, Ltd., 1998.

A conventional wireless communication network regards a concrete wall or the like as an obstacle to communication, and provides a radio wave transmission window on the wall or a communication path that bypasses the wall and connects the space inside the wall and the space outside the wall. Equipment related to the communication path between the space inside the wall and the space outside the wall, and the regeneration and emission of radio waves to the outdoor space are subject to licensing related to the Radio Law and are not easily accessible by anyone.
An object of the present invention is to consider the influence of radio wave propagation loss due to an existing wall, and at a carrier frequency (for example, f1 = 2.4 GHz) permitted to be used in particular, a part of the wall becomes itself. Provides a two-way wireless connection system that can be used as part of the communication path (downlink) from the wall to the terminal inside the wall and as part of the communication path from the wall to the wall (uplink) without any special processing. There is to do.
Still another detailed object of the present invention is to use a radio station (compliant with IEEE802.1.1g / IEEE802.1.1b) that does not require a license other than a specific low-power radio station as a repeater, and the amplifier gain is external. The two-way wireless connection system is configured such that the radiated electric field is set to be equal to or less than the specified value, and the radiated electric field to the outside of the wall is also set to the specified value or less.

In order to achieve the above object, a bidirectional wireless connection system according to claim 1 according to the present invention is provided.
A bidirectional wireless connection system in a wall front space-wall rear space (FAS-BAS) divided by walls,
A wall front space transceiver station located in the wall front space (FAS) and operating at a first carrier frequency (f1);
A first antenna assembly having a large-aperture horn-type reflector installed on a wall rear space (BAS) exposed surface of the wall and collecting radio waves transmitted through the wall; and a first antenna;
A second antenna assembly comprising a second antenna and a reflector plate, the output of the first antenna being directly connected via a line;
A wall rear space transceiver station disposed in a wall rear space (BAS) and including a third antenna and operating at a first carrier frequency (f1);
Amplifying connection means for amplifying the reception output of the second antenna and connecting to the first antenna;
The transmission output of the front space transmitting / receiving station transmitted through the wall is received by the first antenna assembly, radiated from the second antenna of the second antenna assembly, and the third antenna in a region including the near field of the second antenna assembly. The downlink received at
The radio wave from the third antenna is received by the second antenna, and amplified by the amplifier of the amplification connection means as long as the power radiated from the wall does not exceed the maximum output allowed for the space transmitting / receiving station behind the wall. An uplink radiating from the first antenna to the wall front space (FAS);
Is formed.

A bidirectional wireless connection system according to claim 2 according to the present invention is the bidirectional wireless connection system according to claim 1,
The first, second and third antennas are dipole antennas.
The bidirectional wireless connection system according to claim 3 according to the present invention is the bidirectional wireless connection system according to claim 2,
The first antenna of the first antenna assembly is shielded in the wall rear space except in the transmission / reception direction, and does not leak the amplified radio wave into the wall rear space.
If this leak occurs, the system will be undesirably damaged, so a complete leak prevention structure is used.

A bidirectional wireless connection system according to claim 4 according to the present invention is the bidirectional wireless connection system according to claim 1,
The wall rear space transmitting / receiving station is a relay device that communicates with one or more stations in the wall rear space at a second carrier frequency (f2) different from the first carrier frequency, and the one or more stations and the wall It is characterized by enabling two-way communication with a forward space transmitting / receiving station.
The bidirectional wireless connection system according to claim 5 according to the present invention is the bidirectional wireless connection system according to claim 4,
The first carrier frequency is 2.4 GHz, and the second carrier frequency is 5.2 GHz.

A bidirectional wireless connection system according to claim 6 according to the present invention is the bidirectional wireless connection system according to claim 5,
The third antenna is arranged in the near field of the second antenna so that the input radio wave to the third antenna can be received with substantially the same intensity as the incident wave to the concrete wall.
The bidirectional wireless connection system according to claim 7 according to the present invention is the bidirectional wireless connection system according to claim 5,
When the amplification degree G _amp of the amplifier is L ^U _total as the propagation loss of the uplink,
It is set to satisfy L ^U _total + G _amp = 0.
The bidirectional wireless connection system according to claim 8 according to the present invention is the bidirectional wireless connection system according to claim 5,
The relay device uses a specific low power device that does not require a license.

ADVANTAGE OF THE INVENTION According to this invention, a wall (for example, concrete wall) transmission bidirectional | two-way wireless connection system can be provided. For example, the propagation loss at the first frequency f1 (= 2.4 GHz) with a concrete wall thickness W (= 10 cm) is about -8.9 dB from experiments and simulations. They are collected by a large aperture horn antenna placed behind the wall, sent to the second antenna via a coaxial line, and re-radiated to the indoor space. A region where the intensity of the re-radiated electric field is close to the incident wave can be created. A relay device is arranged in this area.
In the uplink, radio waves from the relay device can be received by the second antenna and radiated to the outdoor space via the amplifier and the large aperture horn antenna.

It is a graph which shows the simulation result of the electric field strength distribution along the propagation axis (straight line perpendicular to a wall) of the wall (without the dielectric layer for impedance matching) of the bidirectional wireless connection system according to the present invention. 3 is a graph showing a simulation result when a dielectric layer for impedance matching of λ / 4 is mounted behind the wall shown in FIG. 1 (BAS side). 1 is a block diagram of a bidirectional wireless connection system according to the present invention. It is a perspective view which shows embodiment of a 1st antenna assembly and a 2nd antenna assembly. It is a perspective view which shows the state which has arrange | positioned the 1st antenna assembly and the 2nd antenna assembly on the concrete wall back surface. FIG. 6 is a graph illustrating a radio wave propagation when a 2.4 GHz plane wave (1 V / m) is irradiated from the left in the embodiment shown in FIG. 5 by 3D simulation, and the result is shown as a profile of the electric field intensity on the electric field intensity monitor line. It is a figure which shows the structure of the 3rd dipole antenna of a relay apparatus, the position of the electric field monitor line in a coaxial line, and also shows the relational expression of the electric field strength E (rho) in a coaxial line, and the voltage _Vcoax on a coaxial line. It is a graph which shows the simulation result at the time of using the 3rd dipole antenna of the structure shown in FIG. 7 in the position of 3 cm from a 2nd dipole antenna, and using as a standard antenna for electric field strength measurement. The model used for the radio wave propagation simulation from the 3rd dipole antenna of a relay apparatus to the 2nd dipole antenna of a 2nd antenna assembly is shown. 10 is a graph showing an electric field intensity profile on the electric field monitor line shown in FIG. 9. It is a perspective view of the model used for the simulation of the radio wave propagation from the 1st antenna assembly to the wall front space. It is a perspective view which shows the electric field perpendicular | vertical component distribution snapshot in the model shown in FIG. 13 is a graph showing an electric field intensity profile on the electric field monitor line shown in FIG. 12. It is a graph which shows S11 which anticipated the 1st dipole antenna from the input port of the model shown in FIG. It is a graph which shows the far directivity pattern of the wall front space in the model shown in FIG. It is the top view (a) and side view (b) which show arrangement | positioning of the apparatus of a transmission loss experiment. It is a graph which shows the electric field strength distribution measurement result on an anechoic box central axis. It is the top view (a) and side view (b) which show arrangement | positioning of the apparatus of a downlink radio | wireless connection experiment. It is the graph which shows the result of the downlink radio wave propagation experiment and shows the electric field strength distribution on the central axis of the anechoic box. It is a graph which shows the result of an uplink radio | wireless connection experiment.

Hereinafter, embodiments of the bidirectional wireless connection system according to the present invention will be described in detail with reference to the drawings.
First, an outline of the bidirectional wireless connection system of the present invention will be shown with reference to FIG. 3 showing the overall configuration, and then the principle and operation of this system will be described in terms of items. Then, the structure of each part is demonstrated in detail.

[Schematic configuration of the system of the present application]
FIG. 3 is a block diagram of a bidirectional wireless connection system according to the present invention.
In the space to which the bidirectional wireless connection system according to the present invention is applied, a FAS (concrete wall front space) 7 and a BAS (concrete wall rear space) 8 are separated by a concrete wall 10. The opening of the first antenna assembly 100 is closely arranged on the back surface of the concrete wall 10 (BAS 8 side). The first antenna assembly 100 includes a horn type reflector having a large aperture surface and a first antenna (first dipole antenna 1: see FIG. 4) that receives radio waves collected by the reflector.
The second antenna assembly 200 includes a flat reflector and a second antenna (second dipole antenna 2: see FIG. 4) that receives radio waves collected by the flat reflector.
In the downlink, the output (coaxial output) of the first dipole antenna 1 is directly connected to the coaxial input end of the second dipole antenna 2 (which is the output end in the uplink) via the circulator 4, the coaxial line, and other circulators 5. Connected. That is, the first dipole antenna 1 and the second dipole antenna 2 are directly connected back to back in the downlink.
In the uplink, the coaxial output end of the second dipole antenna 2 is amplified by connecting to an amplifier (G _amp ) 6 via a circulator 5, and the output of the amplifier 6 is coaxially input to the first dipole antenna 1 via a circulator 4. Connected to the end (output end in downlink).
In the vicinity of the second dipole antenna 2 of the second antenna assembly 200, the third dipole antenna 3 of the relay device 300 which is a relay station with a router is disposed. The relay device 300 communicates with, for example, the user PCs (400-1 to 400-n) in the BAS 8 by using radio waves of other frequencies f2 (5.2 GHz).
The third dipole antenna 3 of the relay device 300 is used not only as a transmission / reception antenna with the second dipole antenna 2, but also as a transmission / reception antenna with an antenna (not shown) of the user PC (400-1 to 400-n). The
As the third dipole antenna 3, a dual-frequency antenna is usually used. In the downlink operation, the radio wave f1 (2.4 GHz) from the second dipole antenna 2 of the second antenna assembly 200 is received, amplified in the relay device 300, and the radio wave f2 (5.2 GHz) of other frequencies. To the user PC. In the uplink operation, after receiving the radio wave f2 (5.2 GHz) from the user PC through the dual frequency shared antenna, it is converted to the frequency f1 (2.4 GHz), and the second dipole antenna of the second antenna assembly 200 is converted. 2 is transmitted. The radio wave received by the second antenna assembly 200 is amplified by the amplifier 6 and radiated from the first dipole antenna 1 of the first antenna assembly 100. And it permeate | transmits the concrete wall 10 and is discharge | released to FAS7 and is transmitted to the transmission / reception equipment 500 (for example, base station) of FAS space. It is assumed that relay device 300 is a specific low power device that does not require a license.

[Principle and operation of the system]
Next, the principle and operation of the system will be described separately.
(1) The concrete wall 10 shown as an example in the present invention weakens radio waves. However, about 10% of the energy is transmitted. 0.36 is transmitted as the electric field intensity ratio.
In the present invention, a part of the wall surface of the concrete wall 10 is used as a part of the radio wave path (uplink / downlink).
(2) The radio wave attenuated by the concrete wall 10 is collected over a wide area using the antenna assembly (first antenna assembly 100) having a large opening in the indoor space (BAS8).
(3) The collected power is sent to the indoor second antenna assembly 200 and re-radiated from the second antenna (second dipole antenna 2) to the indoor (BAS8) as a beam having a narrow cross-sectional area. A radio wave space in which the electric field strength reduced by the concrete wall is restored can be created in the indoor space. In other words, by appropriately designing the first antenna assembly 100 and the second antenna assembly 200, a space having an electric field strength equivalent to the radio wave incident on the concrete wall 10 can be created in the indoor space (BAS8). .
(4) The third antenna (third dipole antenna 3) of the relay device 300 is disposed in this region and is closely coupled to the second dipole antenna 2.
As the relay device 300, a commercially available device corresponding to a wireless station (compliant with IEEE802.1.1g / IEEE802.1.1b) that does not require a license other than a specific low-power wireless station can be used. The amplifier gain of the relay device 300 is set so that the radiation field to the outside is not more than a specified value.
(註: IEEE802.1.1g / IEEE802.1.1b: International standard for wireless network connection procedures)
(5) It is preferable that the second dipole antenna 2 and the third dipole antenna 3 are coupled in close proximity so that the input electric field to the third dipole antenna 3 is substantially the same as the virtual electric field strength when there is no wall.
(6) The antenna coupling of the second dipole antenna 2 and the third dipole antenna 3 is shared by bidirectional communication (downlink / uplink).
That is, the downlink signal is transmitted in the flow of second dipole antenna 2 → third dipole antenna 3 → relay device 300 → user PCs 400-1 to 400-n.
The uplink signal is transmitted in the flow of user PCs 400-1 to 400-n → relay device 300 → third dipole antenna 3 → second dipole antenna 2.
(7) The second dipole antenna 2 is a radio wave received from the third dipole antenna 3 (a radio wave obtained by the relay apparatus 300 converting the uplink signal f2 from the user PCs 400-1,..., 400-n to the uplink f1. ) Toward the first dipole antenna 1 of the first antenna assembly 100.
(8) The first antenna assembly 100 irradiates the back surface of the concrete wall 10 (surface on the indoor space BAS side) with the radio wave energy. The irradiation area is the same as the area used for reception in the downlink. Since the light is enlarged and incident on the back surface of the concrete wall 10 as opposed to the downlink, the density is reduced.
(9) Since this weak incident wave is further weakened by the wall, an amplifier 6 is inserted in the uplink to compensate for this.
(10) The gain of the amplifier 6 is set as follows.
It is necessary to set the power radiated to the front space (FAS) 7 (= surface of the wall) of the concrete wall 10 to a value that does not exceed the maximum output power allowed by the relay device 300.
That is, the gain of the amplifier 6 is
(I) Power transmission rate loss from the antenna (third dipole antenna 3) of the relay device 300 to the second dipole antenna 2,
(Ii) the reverse gain of the first dipole antenna 1 that gives the relationship between the input to the first dipole antenna 1 and the electric field strength created on the back of the wall;
(iii) Attenuation of electric field strength by the concrete wall 10
((I) + (ii) + (iii)), that is, a value that cancels out the total attenuation.

[Introducing the concept of other important principles (operational antenna factor in close range)]
(11) The third dipole antenna 3 and the second dipole antenna 2 operate in the vicinity of each other.
Since an analysis generally applicable to the antenna operation in this vicinity region (a radiation electromagnetic field cannot be applied) is not known, in the present invention, the analysis is accurately performed using a three-dimensional electromagnetic field simulation technique. See (15) below for near-field coupling.
In order to help understand the numerical analysis results, further post processing is performed.
(12) The concept of antenna factor AF is introduced in the post-analysis process.
The antenna factor is suitable for quantitatively displaying the performance of an antenna operating in the vicinity region. The antenna factor is a coefficient that combines the electric field strength in the open area space where the antenna is placed and the voltage on the input coaxial line or the output coaxial line of the antenna, and is defined by the following equation.
AF = E / V _i (unit: 1 / m)
E = Electric field in Volts per meter
V _i = Voltage at the antenna terminal in Volts
(13) Radio wave propagation connecting the wall front space 7 (air), the wall 10, the λ / 4 impedance matching layer 11, the first dipole antenna 1, the coaxial line, the second dipole antenna 2, and the third dipole antenna 3 of the relay device 300. The electric field strength along the road is calculated by a three-dimensional electromagnetic field simulation, and the operation performance of the entire antenna system is derived from the three-dimensional electromagnetic field simulation result using the concept of the antenna factor.
(14) In the uplink operation, the radio wave amplified by the amplifier 6 is sent to the first antenna assembly 100 and radiated to the wall front space 7 through the horn reflector and the concrete wall 10. At that time, if radio waves leak into the indoor space from the side wall of the first antenna assembly 100 or the connection portion between the horn and the concrete wall 10, they interfere with radio waves that are the source of amplifier input, and the operation of the entire system becomes unstable. In order to avoid this, the output is usually changed. In the present invention, a horn type reflector using metal plates on the top, bottom, left and right is used, and the horn type reflector and the concrete wall are brought into close contact with each other, and the joint portion is covered with a radio wave absorber, or a quarter wavelength choke flange is provided. Depending on the method of use, etc., radio waves leaking into the room are suppressed and the need for frequency conversion is avoided.
(15) Near field coupling In the near field (Near field region and Antenna region), electrostatic effect and magnetostatic effect are strong.
Electrostatic effect: An effect in which electric charges existing on an antenna (dipole) induce an electric field in the surrounding space. Magnetostatic effect: An effect in which a current existing on an antenna (dipole) induces a magnetic field in the surrounding space. When the charge and current change with time, the electrostatic effect and magnetostatic effect change with time.
A radiation electromagnetic field is formed when the electrostatic effect and the magnetostatic effect change with time.
In the distance, the radiated electromagnetic field component is the main component. Analysis becomes easy.
The region where the electrostatic effect and the magnetostatic effect are converted into a radiated electromagnetic field is the Antenna region, which is a Near field region. Since it is difficult to express with an analytical mathematical expression, a three-dimensional numerical simulation is required.

  The system according to the present invention described above is a two-way wireless connection system in FAS-BAS divided by walls, and the configuration of the system needs to be changed in accordance with the characteristics of the wall against radio waves. Therefore, first, the behavior of a typical concrete wall will be clarified, the matching wall to which the present application system is applied will be described, and an embodiment for this will be described.

[Radio wave propagation loss due to concrete walls]
Consider a case where a 2.4 GHz plane wave is incident on a concrete wall (thickness 10 cm) that separates a wall front space (FAS) and a wall rear space (BAS).
The simulation result of the electric field intensity distribution along the propagation axis (straight line perpendicular to the wall) is shown in FIG.
A finite integration method (Finite Integration Method, Microwave Studio Ver.5.1, DST) was used for this simulation. The dielectric properties of the concrete were ε _r = 9.81 and tan δ = 0.091.
These values are measured values of the sample concrete used in the experiments described later.
FIG. 1 shows an electric field intensity profile on the propagation axis when an incident wave (incident plane wave intensity E _incident is 1 V / m, frequency 2.4 GHz) is incident on a concrete wall 10 having a thickness of 10 cm from the left. It can be seen that the _transmitted wall electric field intensity E _transmitted is 0.36 V / m.
The wall transmission coefficient (WF) is defined as in equation (1).
WF = (E _transmitted / E _incident ) = 0.36 (1)
The radio wave propagation loss L _w due to the wall is L _w = 20 log ₁₀ WF = 20 log ₁₀ 0.36 = −8.87 dB (2)

[Radio wave propagation loss due to matching walls]
Next, FIG. 2 shows a simulation result of the electric field intensity distribution on the propagation axis in the case of using a matching wall in which a dielectric layer for impedance matching of λ / 4 is mounted behind the above-mentioned concrete wall (BAS side).
The transmitted electric field strength is improved to 0.41 V / m. The reflection from the back surface of the concrete wall 10 was suppressed by the λ / 4 dielectric layer 11, and the multiple reflection inside the wall was suppressed. As a result, the propagation loss due to the wall is L _w = 20 log ₁₀ 0.41 = −7.74 dB (3)
And improved by 1.13 dB.
As shown in FIG. 2, the reflection coefficient at the boundary surface between the front surface (FAS7) of the concrete wall 10 and the air is 0.51. From this reflection coefficient, the approximate dielectric constant ε _{r of the} concrete is calculated.
(4)
This ε _r value is close to the original value of 9.81.
As shown in FIG. 2, a plane wave of 1 V / m is incident on a concrete wall 10 having a thickness of 10 cm from the left. A dielectric (PET) layer 11 having a thickness of 1.8 cm is mounted on the back surface of the concrete wall 10 (BAS 8 side). The electric field intensity profile on the propagation axis under this condition, and the transmitted wave electric field intensity is 0.41 V / m. The frequency of the incident wave is 2.4 GHz, the concrete dielectric properties ε _r = 9.81 and tan δ = 0.091 are the same as those of the above-described typical wall, and the relative dielectric constant of the dielectric (PET) layer 11 having a thickness of 1.8 cm. The rate ε _rm = 3.14.

Furthermore, when a dielectric layer is mounted on the front side in addition to the back side of the wall, the propagation loss is L _w = 20 log ₁₀ 0.48 = −6.38 dB (5)
To reduce. However, since it is actually difficult to work outside the wall (front surface), a method that can be realized only by working inside the wall (back surface) in the bidirectional wireless connection system according to the present invention will be described. -6.38 dB is propagation loss due to absorption of concrete, and the remaining (-8.87 + 6.38) =-2.49 dB is the contribution of reflection at the interface.

[First antenna assembly, second antenna assembly]
FIG. 4 is a perspective view showing an embodiment of the first antenna assembly 100 and the second antenna assembly 200.
As shown in FIG. 4A, the first antenna assembly 100 includes a large aperture horn reflector, a first dipole antenna 1 and an input / output coaxial line.
The large aperture horn type reflector includes a horn 101 and upper and lower metal plates 102 and 103.
The opening 104 of the large aperture horn reflector, which is brought into close contact with the concrete wall 10 directly or via the dielectric layer 11, is 25 cm × 36 cm, and the metal plates 102 and 103 arranged above and below are Each is 25.5 cm × 36 cm.
The basic configuration of the first, second and third dipole antennas is common.
The total length of the first dipole antenna 1 consisting of 1a, gap, and 1b (not shown; corresponding to 3a, gap, and 3b in FIG. 7) is 4.17 cm, 4.53 cm from the bottom of the horn (reflector apex angle). Placed in position. One 1a (corresponding to 3a in FIG. 7) of the first dipole antenna 1 is the central conductor 1d (not shown; corresponding to 3d in FIG. 7) of the 50Ω coaxial line, and the other 1b (corresponding to 3b in FIG. 7) is the outer conductor. 1c (not shown; corresponding to 3c in FIG. 7).
As shown in FIG. 4B, the second antenna assembly 200 is a coaxial line connected to the flat plate reflector 201 (12.5 cm × 12.5 cm), the second dipole antenna 2 and the first dipole antenna 1. It is configured. The total length (2a, gap, and 2b) of the second dipole antenna 2 is 4.67 cm, and is arranged at a position 2.32 cm from the flat plate reflector 201.
In the uplink operation, the radio wave connected through the circulator 5 and amplified by the amplifier 6 enters the first antenna assembly 100 from the coaxial line input end face, and enters the coaxial line, the first dipole antenna 1 and the horn type reflector. The horn-shaped reflector passes through the concrete wall 10 and is radiated to the wall front space 7. At that time, it is necessary to prevent radio waves from leaking out from the side surface of the first antenna assembly 100 and the joint portion with the concrete wall 10 into the wall rear space 8. Therefore, leaking radio waves from the joints by covering the joint between the horn tip (opening surface) and the concrete wall 10 with a radio wave absorber (not shown) or attaching a quarter-wave choke flange. Suppress.

[First antenna assembly, second antenna assembly, second antenna and third antenna]
FIG. 5 is a perspective view showing a state in which the first antenna assembly 100 and the second antenna assembly 200 are arranged on the back surface of the concrete wall.
As described above, the first antenna assembly 100 includes a large aperture horn type reflector and a dipole antenna, and the second antenna assembly 200 includes a flat plate reflector and a dipole antenna.
The distance between the second dipole antenna 2 of the second antenna assembly 200 and the third dipole antenna 3 of the relay device 300 is 3 cm.
The role of the concrete wall back antenna assembly in the downlink is to collect radio waves transmitted and attenuated through the concrete wall 10 over a wide area to the first dipole antenna 1 and send it to the second dipole antenna 2, and near the dipole of the second dipole antenna 2. A region having a high electric field strength is created and coupled to the third dipole antenna 3 of the relay device 300 arranged there.

[Downlink simulation]
In the model of FIG. 5, radio wave propagation when irradiated with a 2.4 GHz plane wave (1 V / m) from the left was analyzed by 3D simulation. The electric field strength profile on the electric field strength monitor line is shown in FIG. FIG. 6 shows an enlarged scale of the vertical scale at the bottom, and also displays a value converted to voltage on the coaxial line.
From FIG. 6, the plane wave electric field intensity incident on the front surface of the concrete wall is E _incident = 1.0 V / m, the intensity of the radio wave after passing through the wall is E _transmitted = 0.36 V / m, and the first dipole antenna 1 to the second dipole antenna. The voltage of the wave traveling on the coaxial line toward V ₂ is V _coax12 = 0.0257 V, and the radiation electric field intensity at the position where the third dipole antenna 3 of the relay device 300 is disposed (3 cm from the second dipole antenna 2) is It can be understood that E (3 cm) = 0.961 V / m, and the coaxial line voltage connected to the third dipole antenna 3 of the relay apparatus 300 is V _coaxRep = 0.0147V.
From FIG.
(6)
Can be written. k = 9.920 × 10 ⁻⁴ is a coefficient for converting the electric field intensity on the monitor line in the coaxial line into a voltage.
here,
AF ^D ₁ is an antenna factor of the first dipole antenna 1 in the downlink, and AF ^D ₂ is an antenna factor of the second dipole antenna 2 in the downlink.
Since electric field strength Eρ in the coaxial line is not determined to depend on the distance from the central axis of the monitor line unique, it is also shown the values in terms of voltage V _coax coaxial line. The conversion process is shown in FIG.

FIG. 7 shows the structure of the third dipole antenna 3 of the relay device 300 and the position of the electric field monitor line in the coaxial line.
3a and 3b of the 3rd dipole antenna 3 are 2.4 cm, respectively.
The position of the electric field monitor line in the coaxial line is 0.083 cm from the central axis of the coaxial line. The conversion formula between the electric field on the electric field monitor line and the coaxial line voltage is shown in the upper part of the figure.
(6)
(7)
It is. The design requirements for the downlink are:
WF = 0.36 (8)
Under the conditions of
E (3cm) / E _incident ≒ 1 (9)
Is to realize.
In the design example of FIG. 5, the radio wave attenuated by the wall is collected from a wide area by the first antenna assembly 100 having a horn-type reflector having a large aperture surface, and a high output voltage V _coax12 is _generated . This is fed to the second antenna assembly 200 and re-radiated to create a region satisfying the expression (9) in the vicinity thereof.
The third dipole antenna 3 of the relay device 300 is disposed in this area. The second antenna assembly 200 includes the flat plate reflector 201 and the second dipole antenna 2 as described above. Since the third dipole antenna of the relay device 300 also serves as a transmission / reception antenna in the 5.2 GHz band, a flat reflector is employed. Now, from the equations (6)-(8),
WF × AF ^D ₂ ≒ AF ^D ₁ (10)
Then, the equation (9) is satisfied.

The proximity coupling between the second dipole antenna and the third dipole antenna will be further described. As described above, FIG. 6 shows the result of analyzing the downlink operation using the simulation model of FIG. First, the state of the electric field in the space behind the wall will be described.
FIG. 6 shows a state in which a plane wave is irradiated from the front of the wall and the radio wave propagates to the indoor space behind the wall as an electric field intensity distribution along the electric field monitor line. The horizontal axis in FIG. 6 is the distance cm on the monitor line (the starting point is the left end of the model), and the vertical axis is the electric field strength V / m. Note that the vertical scale is changed midway.
In FIG. 6, a region 7 is a wall front space, a region 10 is a concrete wall (thickness 10 cm), and a region 8 is a wall rear space. The positions of the first dipole antenna 1, the second dipole antenna 2, and the third dipole antenna 3 are indicated by 1, 2, and 3, respectively. The area between the rear face of the wall and the first dipole antenna 1 is surrounded by a horn-shaped reflector, the space between the first dipole antenna 1 and the second dipole antenna 2 is the space inside the 50Ω coaxial line, and the second dipole antenna 2 is behind A radio wave is re-radiated to the indoor space (BAS8), and a third dipole antenna 3 is disposed at a position 3 in the vicinity thereof. A short 50Ω coaxial line is connected to the third dipole antenna 3 as a reception signal output line.
The waveform in region 7 is a standing wave generated by an incident plane wave (1 V / m) and a reflected wave reflected from the front surface of the wall.
The waveform in the region 10 is a standing wave generated by interference between a wave propagating inside the wall while being attenuated from left to right and a wave reflected from the rear surface of the wall and propagated while being attenuated from right to left.
The waveform between 1 and 2 is a waveform in which a standing wave generated by a slight impedance mismatch is superimposed on a wave transmitted from the first dipole antenna 1 to the second dipole antenna 2.
The waveform between 2 and 3 shows the electric field strength of the radio wave radiated to the BAS 8.
The short horizontal line behind 3 is a waveform indicating the electric field strength distribution in the 50Ω received signal output coaxial line of the third dipole antenna 3. Since the coaxial line is matched and terminated at 50Ω, the standing wave component is zero.
The coaxial line has an inner conductor radius of 0.0457 cm, an outer conductor inner diameter of 0.151 cm, an outer conductor outer diameter of 0.18 cm, a dielectric inner diameter of 0.0457 cm, and a dielectric outer diameter of 0.151 cm. The electric field monitor line is located at a radius of 0.083 cm from the center of the coaxial line.
From the average value of the waveform of the region 7, the incident wave electric field strength is 1 V / m. From the average value of the waveform of the region 10 and the result of FIG. 1, the electric field strength after transmission through the wall is 0.36 V / m, 1 and 2 From the average value of the waveform between the first dipole antenna 1 and the second dipole antenna 2 through the coaxial line, the electric field strength of the wave is 25.93 V / m (0.0257 V in terms of coaxial line voltage) It became.
In order to calculate the radiated electric field intensity at a position 3 cm from the second dipole antenna 2, the third dipole antenna 3 is used as a standard antenna for measuring electric field intensity. The electric field strength in the output coaxial line of the third dipole antenna 3 is 14.77 V / m from FIG. 6 and is 0.0147 V in terms of the coaxial line voltage.
FIG. 8 shows an enlarged electric field intensity distribution in the vicinity of the third dipole antenna used as the standard dipole antenna.
As shown in FIG. 8, when this standard dipole antenna is arranged in a space where a plane wave having an electric field strength of 1 V / m is propagated, the voltage induced in the 50Ω output coaxial line is 0.0153V.
The antenna factor (AF) of this standard dipole antenna is AF _standard = E _incident / V _coax = 1 / 0.0153 = 65.36 (11)
It becomes.
When the above two relationships are combined, the radiation field intensity at a position 3 cm from the second dipole antenna 2 is E (3 cm) = 65.36 × 0.0147 = 0.916 V / m (12)
Is calculated.

[Uplink simulation as a whole]
In the uplink simulation, radio wave propagation from the third dipole antenna 3 of the relay device 300 to the second dipole antenna 2 and radio wave propagation from the first dipole antenna 1 of the first antenna assembly 100 to the outdoor space (FAS7). Perform in two stages.

[Uplink simulation from repeater to second dipole antenna]
FIG. 9 shows a model used for a radio wave propagation simulation from the third dipole antenna 3 of the relay device 300 to the second dipole antenna 2 of the second antenna assembly 200.
2.4 GHz and 1 W are applied to the coaxial line input port of the relay device 300 to simulate radio wave propagation to the second dipole antenna 2.
FIG. 10 shows the electric field intensity profile on the electric field monitor line.
As shown in FIG. 10, V _coaxRep = 6.791V and V _coax2 = 3.689V.
From FIG. 10, the input to the third dipole antenna 3 of the relay device 300 is P _in (third dipole antenna 3) = (6.791 ² /50)=0.922W (13)
The output of the second dipole antenna 2 of the second antenna assembly 200 is P _out (second dipole antenna 2) = (3.698 ² /50)=0.274 W (14)
The ratio T _RepToAnt2 (3 cm) of power transmitted to the second dipole antenna 2 that is 3 cm away from the third dipole antenna 3 of the relay device 300 is T _RepToAnt2 (3 cm) = (0.274 / 0.922) = 0.297 (15)
It is.
Here, this is treated as an apparent radio wave propagation loss L _RepToAnt2 (3 cm). Radio wave propagation loss is T _RepToAnt2 (3 cm) = L _RepToAnt2 (3 cm) = 0.297
or (16)
L _RepToAnt2 (3 cm) (dB) = ₁₀ log ₁₀ 0.297 = −5.28 dB
It becomes.
By the way, the radio wave propagation loss when the distance between the third dipole antenna 3 and the second dipole antenna 2 of the relay device 300 is 12 cm is L _RepToAnt2 (12 cm) = 0.0465.
or (17)
L _RepToAnt2 (12 cm) (dB) = ₁₀ log ₁₀ 0.0465 = −13.33 dB
It becomes. In the experiment described later, the distance was set to 12 cm.

[Uplink simulation from the first dipole antenna to the space in front of the wall]
FIG. 11 is a perspective view of a model used for a radio wave propagation simulation from the first dipole antenna 1 to the wall front space (FAS) 7 of the first antenna assembly 100, and the first through the concrete wall 10 having a thickness of 10 cm. 2 is a radiation characteristic simulation model of the dipole antenna 1.
2.4 GHz, 1 W was applied to the input port of the 50Ω coaxial line connected to the first dipole antenna 1 to excite radio waves.
12 is an electric field vertical component distribution snapshot in three orthogonal planes, and FIG. 13 is a graph showing electric field intensity profiles on the electric field monitor lines C1, C2, and C3 in FIG.

FIG. 14 shows an S11 frequency locus in which the first dipole antenna 1 is viewed from the input port. Under the matching state of FIG. 14, the voltage V _coax1 on the input coaxial line is 6.015V, and the input power of the first dipole antenna 1 is P _in (first dipole antenna 1)
= (6.015 ² /43.41) = 0.833W (18)
The reference impedance in this numerical calculation was 43.41Ω.
A far directivity pattern (linear scale) is shown in FIG.
In FIG. 15, the radiation efficiency is the ratio of the radiated power to the power applied to the input port of the first dipole antenna 1. Therefore, radiation efficiency = 0.1666 gives a propagation loss (L _{ant1 To Air} ) from the first dipole antenna 1 to the front wall space (FAS) 7.
L _ant1ToAir = 0.1666
or (19)
L _ant1ToAir (dB) = ₁₀ log ₁₀ 0.1666 = −7.78 dB
It becomes.
Radiation efficiency = 0.1666 corresponds to a concrete wall transmission coefficient of 0.407, which is slightly higher than 0.36. This is considered to be a reflection suppressing effect by the λ / 4 dielectric layer 11 inserted between the wall back surface and the first antenna assembly 100 (see FIG. 2).

[Details of uplink design conditions]
The radio wave propagation loss (L ^U _total ) from the relay device 300 to the wall front space (FAS) 7 is the propagation loss from the relay device 300 to the second dipole antenna 2 (see equation (16)) and the first dipole antenna 1 to the wall. It is given by the sum of the propagation loss up to the front space (FAS) 7 (see equation (19)). That means
L ^U _total (dB) = L _RepToAnt2 (dB) + L _ant1ToAir (dB)
= −5.28−7.78 = −13.06 dB (20)
It becomes. Insert an amplifier with gain G _amp (dB) in the uplink path,
L ^U _total + G _amp = 0 (21)
Set the gain to satisfy. This is the uplink design condition.
Under this design condition, the electric field intensity radiated to the external space of the wall does not exceed the intensity of the electric field radiated by the relay device in the room.
Further, in the first antenna assembly 100, a horn type reflector is used, and the opening 104 thereof is used in close contact with the back surface of the wall 10 through the dielectric layer 11.
The amplified radio wave is confined inside the horn and is not radiated into the indoor space.
If the horn opening size is large, a highly directional beam can be formed in the outdoor space.
In this design example, directivity (linear scale) = 34.22.

[Design system performance evaluation experiment Propagation loss measurement]
FIG. 16 shows a layout of the transmission loss experiment. In the figure, the upper part (a) is a plan view and the lower part (b) is a side view. The shape and size of the anechoic box used in the transmission loss experiment is as follows.
Left anechoic box length x width x height = 100cm x 65cm x 65cm
Right anechoic box length x width x height = 150cm x 65cm x 65cm
Propagation loss is measured using a wall sample (70 cm × 70 cm × 10 cm) using typical architectural concrete (2.3 × 10 ³ kg / m ³ ).
A wall sample (112.7 kg) was sandwiched between left and right anechoic boxes and held vertically as shown in FIG. The anechoic box has a structure in which an electromagnetic wave absorbing plate having a thickness of 2 mm is pasted on the surface of an aluminum plate. This radio wave absorbing plate is designed to function as a non-reflective surface at 2.5 GHz in the state of being lined with a conductor plate. It did not function as a non-reflective surface when pasted on a concrete board.
In order to avoid this problem, transmission loss was measured by irradiating only the central part of the wall with no aluminum plate on the vertical side of the concrete wall parallel to the electric field. A dipole antenna with a reflector in the left anechoic box was excited with an input signal of 2.4 GHz and 0 dBm from an excitation source. In this state, the standard dipole antenna was scanned on the central axis of the anechoic box to measure the electric field strength distribution. A spectrum analyzer (Spectrum Master, MS2721, Anritsu) was used for electric field strength measurement. The measurement results are shown in FIG.

FIG. 17 is a graph showing the measurement result of the electric field intensity distribution on the central axis of the anechoic box.
The concrete wall thickness is 10 cm, the vertical axis indicates the electric field strength (mV / m), and the horizontal axis indicates the distance (cm) on the axis.
From FIG. 17, the propagation loss L _w is L _w (dB) = 20 log ₁₀ (5.00 / 13.85) = − 8.85 dB (22)
The reflection coefficient Γ at the front surface of the wall is Γ = (21.00-13.85) /13.85=0.516 (23)
Ignoring the influence of the reflection from the rear surface of the wall and approximating the relative permittivity of the concrete wall, ε _r = ((1 + 0.516) / (1−0.516)) ² = 9.81 (24)
The relative dielectric constant thus obtained was used for the simulation.

[Design system performance evaluation experiment Downlink radio wave propagation experiment]
FIG. 18 shows the arrangement of the apparatus for the downlink radio wave propagation experiment. The upper part (a) of FIG. 18 is a plan view, and the lower part (b) is a side view.
The shape of the anechoic box is as described above.
The structure of the first antenna assembly 100 is as shown in FIG. That is, the opening of the first antenna assembly 100 is 36 cm wide × 25 cm long. A metal reflector was attached to the upper and lower sides of the corner reflector to make a horn-type reflector. The distance between the first dipole antenna 1 with a total length of 4.17 cm and the reflector apex angle (the bottom of the horn) is 4.53 cm. The feed line is a 50Ω semi-ridged coaxial line. As shown in FIG. 4B, the second antenna assembly 200 is a 12.5 cm × 12.5 cm flat reflector dipole antenna (the flat reflector 201 and the second dipole antenna 2).
As shown in FIG. 18, in the arrangement of the apparatus for the downlink wireless connection experiment, a PET (polyethylene terephthalate) (ε _r = 3.05) layer (λ / 4 impedance matching layer) having a thickness of 1.8 cm is provided on the rear surface of the concrete wall. It is attached. The first antenna assembly 100 (including the high gain first dipole antenna 1) and the second antenna assembly 200 (including the low gain second dipole antenna 2) were directly connected back to back in the right anechoic box.
The aforementioned λ / 4 impedance matching layer was inserted between the concrete wall and the first antenna assembly 100. The matching layer is formed by laminating 2 mm and 3 mm thick PET plates.
Standing waves were measured with layer thicknesses of 1.2, 1.8, 2.0, and 2.2 cm. The standing wave ratio was minimized at 1.8 cm. From the measurement results was obtained PET layer within the wavelength lambda _PET and the relative dielectric constant epsilon _PET.
12.5 / (ε _PET ) ^1/2 = 7.2 or ε _PET = (12.5 / 7.2) ² = 3.01
(25)
This value is required for the λ / 4 impedance matching layer.
(26)
Close to. Under the above arrangement, the antenna in the left anechoic box was excited, and the electric field strength distribution on the central axis of the left and right anechoic boxes was measured. The measurement results are shown in FIG.
FIG. 19 is a graph showing the results of a downlink radio wave propagation experiment.
This figure shows the electric field strength distribution on the central axis of the anechoic box, the vertical axis is the electric field strength (mV / m), and the horizontal axis is the distance (cm) on the central axis of the anechoic box.
The electric field strength in the vicinity of the second dipole antenna 2 of the second antenna assembly 200 was 13.85 mV / m or more, and the electric field intensity incident on the front surface of the concrete wall was 13.85 mV / m.
That is, this experimental result showed that the electric field strength exceeded the electric field strength of the concrete wall incident wave of 13.85 mV / m in the vicinity of the second dipole antenna 2.

[Uplink radio wave propagation experiment]
The experiment related to the uplink operation was performed mainly for confirming the radio wave propagation characteristics of the first antenna assembly 100 in the reverse direction (from indoor to outdoor).
In the uplink radio wave propagation experiment, the excitation antenna was removed from the left anechoic box of FIG. 18, and a bare dipole antenna was placed 12 cm from the second dipole antenna 2 in the right anechoic box. 0 dBm, 2.4 GHz was applied to this dipole antenna, and the electric field strength distribution on the central axis of the left anechoic box was measured. The measurement results are shown in FIG.
FIG. 20 is a graph showing the results of an uplink wireless connection experiment.
The vertical axis is the electric field strength (mV / m), the horizontal axis is the distance (cm) from the wall surface on the propagation axis, the measured electric field strength at the dipole position of the second dipole antenna 2 is 17.12 mV / m, the front of the concrete wall To 25 cm, the measured electric field strength is 1.92 mV / m.
When the uplink propagation loss L ^U _overall is estimated from the results of FIG. 20, L ^U _total (dB) = 20 log ₁₀ (1.92 / 17.12) = − 19.0 dB (27)
It becomes.
The radio wave propagation loss L _RepToAnt2 (12 cm) (dB) by simulation when the distance from the third dipole antenna 3 of the relay device 300 is 12 cm was _−13.33 dB as shown by the equation (17).
Ratio of input power to the input terminal of the first dipole antenna 1 and power radiated to the wall front space (FAS) 7 = 0.1666 (refer to the explanatory text of FIG. 15 radiation efficiency = 0.1666). Converting this to dB yields -7.78 dB (see equation (19)).
The power transmission loss from the third dipole antenna 3 to the wall front space (FAS) 7 is given by their sum.
Therefore,
L ^U _total (dB) =-13.33-7.78 = -21.11 dB (28)
Thus, the value obtained in the experiment is close to -19.0 dB.
It can be said that this shows the validity of the design method described in the uplink simulation.

Various modifications can be made within the scope of the present invention with respect to the embodiment described in detail above.
As an example, a dipole antenna is used in the link in the space behind the wall. A waveguide horn antenna; b. Various planar antennas (but in combination with a suitable horn reflector) can also be used. Although the horn-shaped corner reflector is used as the large-diameter reflector in the first antenna assembly 100, a parabolic reflector can also be used.

1 First antenna (dipole)
2 Second antenna (dipole)
3 Third antenna (dipole)
2a, 3a One of dipoles 2b, 3b The other of dipoles 2c, 3c Coaxial outer conductor 2d, 3d Coaxial center conductor 4,5 Circulator 6 Amplifier 7 Wall front space (FAS)
8 Wall rear space (BAS)
DESCRIPTION OF SYMBOLS 10 Concrete wall 11 Dielectric layer 100 1st antenna assembly 101 Horn 102 Upper metal plate 103 Lower metal plate 200 Second antenna assembly 201 Flat reflector 300 Relay device (relay station with router)
400-1 to 400-n User PC
500 Transmission / reception facilities (base station)

Claims (8)

A two-way wireless connection system in a wall front space-wall rear space divided by walls,
A wall front space transceiver station arranged in the wall front space and operating at a first carrier frequency;
A first antenna assembly having a large-aperture horn-type reflector, which is installed on a wall rear space exposed surface of the wall and picks up radio waves transmitted through the wall, and a first antenna;
A second antenna assembly comprising a second antenna and a reflector plate, the output of the first antenna being directly connected via a line;
A wall rear space transceiver station that is disposed in the wall rear space and includes a third antenna and operates at a first carrier frequency;
Amplifying connection means for amplifying the reception output of the second antenna and connecting to the first antenna;
The transmission output of the front space transmitting / receiving station transmitted through the wall is received by the first antenna assembly, radiated from the second antenna of the second antenna assembly, and the third antenna in a region including the near field of the second antenna assembly. The downlink received at
The radio wave from the third antenna is received by the second antenna, and amplified by the amplifier of the amplification connection means as long as the power radiated from the wall does not exceed the maximum output allowed for the space transmitting / receiving station behind the wall. An uplink radiating from the first antenna to the space ahead of the wall;
A two-way wireless connection system characterized by forming The bidirectional wireless connection system according to claim 1, wherein
The bidirectional wireless connection system, wherein the first, second and third antennas are dipole antennas. The bidirectional wireless connection system according to claim 2, wherein
The two-way wireless connection system, wherein the first antenna of the first antenna assembly is shielded in the wall rear space except in the transmission / reception direction, and the amplified radio wave is not leaked into the wall rear space. The bidirectional wireless connection system according to claim 1, wherein
The wall rear space transmission / reception station is a relay device that communicates with one or more stations in the wall rear space at a second carrier frequency different from the first carrier frequency, and the wall front space transmission / reception with the one or more stations. A bidirectional wireless connection system that enables bidirectional communication with a station. The bidirectional wireless connection system according to claim 4, wherein
The bidirectional wireless connection system, wherein the first carrier frequency is 2.4 GHz and the second carrier frequency is 5.2 GHz. The bidirectional wireless connection system according to claim 5, wherein
A two-way wireless connection system, wherein the third antenna is disposed in the near field of the second antenna, and can receive the input radio wave to the third antenna with substantially the same intensity as the incident wave to the concrete wall. The bidirectional wireless connection system according to claim 5, wherein
When the amplification degree G _amp of the amplifier is L ^U _total as the propagation loss of the uplink,
A bidirectional wireless connection system that is set to satisfy L ^U _total + G _amp = 0. The bidirectional wireless connection system according to claim 5, wherein
A bidirectional wireless connection system using a specific low power device that does not require a license for the relay device.