JP5770691B2 - Wireless communication system and wireless communication method - Google Patents

Description

  The present invention relates to a wireless communication system and a wireless communication method provided with an array antenna including a plurality of antenna elements.

  In recent years, it has been required to realize gigabit-class high-speed wireless communication in a limited frequency band. One of the implementation methods is a MIMO (Multiple-Input Multiple-Output) transmission technology. In MIMO transmission, different signals are transmitted from multiple transmitting antennas at the same time and at the same frequency, and each signal is separated by signal processing on the receiver side by using a multipath environment between the transmitter and the receiver. And decrypt. Thereby, it is possible to improve the communication speed according to the number of transmitting / receiving antenna elements without expanding the use frequency band.

  Normally, MIMO transmission assumes a multipath environment. When the environment between the transmitter and the receiver is not a multipath environment, the propagation paths of a plurality of signals transmitted and received are substantially equal, and the spatial correlation increases. For this reason, signal separation becomes difficult and the channel capacity decreases. However, in recent years, for example, as shown in Non-Patent Document 1, the MIMO transmission technology is also used in short-range communication in which the transmission antenna and the reception antenna are close to each other and the environment between the transmitter and the receiver is not a multipath environment. It has been noted that it can be applied. Hereinafter, MIMO transmission in near field communication is referred to as near field MIMO transmission.

  According to the technique of Non-Patent Document 1, in short-range MIMO transmission, the antenna spacing is appropriately set according to the distance between the transmitter and the receiver, so that the antenna can be used even in a multipath environment. The spatial correlation between them becomes low, and a high channel capacity can be achieved. Non-Patent Document 2 proposes a short-range ultrahigh-speed wireless relay system that uses the inside of an obstacle such as a concrete wall as a propagation path. According to this short-range ultrahigh-speed wireless relay system, high-speed communication by short-range MIMO transmission is possible even in an environment where a line-of-sight antenna cannot be obtained due to a wall or the like at a short distance.

  Further, in Non-Patent Document 2, studies for increasing the channel capacity in short-distance MIMO transmission are performed. However, in order to realize actual MIMO transmission, in addition to a technique for increasing the channel capacity, a signal processing technique in the transceiver is required. Regarding this signal processing technique, Non-Patent Document 1 is known as the characteristic of eigenmode transmission (hereinafter referred to as EM-BF), which is known as an optimal transmission / reception method for MIMO transmission, and a method for performing signal processing only on the receiving side. The characteristics of zero forcing (hereinafter referred to as ZF) are compared. Non-Patent Document 2 shows that the characteristics of the EM-BF and the characteristics of the ZF substantially coincide with each other due to the optimum element spacing of the array antenna.

FIG. 12 is an explanatory diagram illustrating an arrangement example of antenna elements in short-range MIMO transmission. In FIG. 12, the number of antenna elements Tx _j on the transmission side (j is a positive integer satisfying 1 ≦ j ≦ M and M is a positive integer satisfying M ≧ 2) and the antenna element Rx _i (reception side). i is a positive integer satisfying 1 ≦ i ≦ M. The antenna element Tx _j on the transmission side is arranged on the plane PT, and the antenna element Rx _i on the reception side is in the propagation space FS with the antenna element Tx _j on the transmission side on the plane PR parallel to the plane PT. It is arrange | positioned so that it may oppose on both sides. The distance between the plane PT and the plane PR is D. Hereinafter, the distance D between the plane PT and the plane PR is referred to as “transmission / reception interval D”. In addition, on both the transmitter side and the receiver side, the distance between any two adjacent antenna elements is d. In the following, for simplification of description, the case of M = 2, that is, the case of 2 × 2 (two inputs and two outputs) near field MIMO transmission will be described.

  FIG. 13 is a model diagram of 2 × 2 short-range MIMO transmission. In the 2 × 2 short-distance MIMO transmission shown in FIG. 13, when the channel matrix H is expressed by Equation (1), the received signal is expressed by Equation (2).

Here, in the expressions (1) and (2), the element h _ij (i and j are positive integers of 2 or less) is a signal propagated through the channel from the transmitting antenna element Tx _j to the receiving antenna element Rx _i . Is a matrix element that indicates the change rate of the phase and amplitude of, for example, by complex number expression. Further, s _j is a signal transmitted from the transmitting antenna element Tx _j, r _i is a matrix element representing the signal received by the receiving antenna element Rx _i, n _i is a matrix representing the noise added to the received signal Is an element.

  In addition, when a reception weight matrix W for signal separation in 2 × 2 MIMO transmission is expressed as in Expression (3), a signal output to each receiving circuit after reception weight calculation is expressed in Expression (4).

In Expressions (3) and (4), matrix elements w _ij (i and j are each a positive integer equal to or less than 2) are data series corresponding to the data series s ′ transmitted by the transmitting antenna element Tx _i . In order to extract s ′ _i , the weight multiplied by the signal received by the receiving antenna element Rx _j is shown.

In 2 × 2 short-range MIMO transmission, the antenna element spacing d is such that the phase difference θ _H = tan ⁻¹ (h ₂₁ / h ₁₁ ) = tan ⁻¹ (h ₁₂ / h ₂₂ ) of each channel is 90 degrees. The channel capacity is maximized when is set. Hereinafter, the antenna element interval d that maximizes the channel capacity is referred to as “optimal element interval d _opt ”.

When the antenna element interval d is set to the optimum element interval d _opt , the channel matrix H of 2 × 2 short-distance MIMO transmission is approximated by Equation (5). Here, in Expression (5), a propagates the amplitude of the signal propagated through the channel from the transmission antenna element Tx ₁ to the reception antenna element Rx ₁ and the channel from the transmission antenna element Tx ₁ to the reception antenna element Rx ₂ . Represents the ratio to the amplitude of the measured signal.

At this time, the reception weight matrix W _{ZF in ZF} is approximated by Equation (6).

  From Equation (5) and Equation (6), the product of the channel matrix and the reception weight matrix is represented by a diagonal matrix as shown in Equation (7). That is, the signals transmitted from the respective transmission antennas are separated by multiplying the reception weight in the receiver, and are received without causing interference.

Honma, Nishimori, Seki, Mizoguchi, “Evaluation of Transmission Capacity in Near-field MIMO Communication” IEICE Technical Report, AP2008-125, Nov. 2008 Seki, Nishimori, Honma, Nishikawa, “Short-range Ultra-high-speed Relay System” IEICE Technical Report, AP2008-124, Nov. 2008

As described above, in 2 × 2 short-distance MIMO transmission, the phase difference θ _H = tan ⁻¹ (h ₂₁ / h ₁₁ ) = tan ⁻¹ (h ₁₂ / h ₂₂ ) of each channel is 90 degrees. The channel capacity is maximized when the distance d between the antenna elements is set.
However, normally, at the design stage of a planar array antenna as shown in FIG. 12, a specific transmission / reception interval D is assumed, and the interval d of the antenna elements is set to a specific value according to the transmission / reception interval D. In this antenna manufacturing process, antenna elements are arranged on one substrate at a specific interval d set in the above-described design stage. Therefore, not only the phase difference theta _H of each channel 90 degrees and the transmission and reception intervals other than transmission and reception interval D assumed in the design stage, there is a problem that the characteristics of short-range MIMO transmission is deteriorated.

  In addition, the above-described problem is caused by setting the transmission / reception interval D as shown in Non-Patent Document 2, as in a system that performs short-distance MIMO transmission by installing transmitters / receivers on both sides of a wall between rooms or indoors / outdoors. It becomes even more noticeable when it cannot be adjusted to an arbitrary interval.

The present invention has been made in order to solve the above-described problems, and an object of the present invention is to make the actual transmission / reception interval deviate from the transmission / reception interval assumed in the design stage of the planar array antenna, and the channel phase difference θ _H is a desired value. To provide a wireless communication system and a wireless communication method capable of bringing the phase difference θ _{H of the} channel close to a desired value without changing the interval between the antenna elements even when it deviates from (for example, 90 degrees). is there.

The present invention has been made to solve the above-described problems, and a wireless communication system according to an aspect of the present invention includes a transmission array antenna including a plurality of transmission antenna elements, and a plurality of transmission antenna elements facing each other. A radio communication system comprising a receiving array antenna composed of a plurality of receiving antenna elements that are arranged between the transmitting array antenna and the receiving array antenna and have a relative permittivity according to an applied temperature A phase rotating unit that rotates a phase of a radio wave propagating in the dielectric layer according to the temperature, and a heat generating unit that applies the temperature to the dielectric layer. A phase for estimating a phase difference of a channel formed between each transmitting antenna element of the transmitting array antenna and each receiving antenna element of the receiving array antenna Based on the phase difference estimated by the estimation unit and the phase difference estimation unit, by controlling the heat generation amount of the heat generation unit of the phase rotation unit, the desired channel capacity can be obtained. And a phase difference adjusting unit that adjusts the phase difference.

A wireless communication system according to an aspect of the present invention includes a transmission array antenna configured by a plurality of transmission antenna elements, and a reception array antenna configured by a plurality of reception antenna elements respectively facing the plurality of transmission antenna elements. A dielectric communication system comprising: a dielectric layer disposed between the transmitting array antenna and the receiving array antenna and having a relative dielectric constant that changes according to an applied electric field strength; and the dielectric layer A pair of electrodes for applying the electric field, a phase rotating unit for rotating the phase of the radio wave propagating in the dielectric layer according to the strength of the electric field, and each transmitting antenna of the transmitting array antenna A phase difference estimation unit for estimating a phase difference of a channel formed between an element and each reception antenna element of the reception array antenna, and the phase difference estimation unit. A phase difference adjustment unit that adjusts the phase difference of the channel so as to obtain a desired channel capacity by controlling a voltage between the pair of electrodes of the phase rotation unit based on the estimated phase difference. And the dielectric layer has a first path between the transmitting antenna element of the transmitting array antenna and the receiving antenna element of the receiving array antenna, which are in a mutually opposing arrangement relationship, and oblique directions with respect to each other. In the second path between the transmitting antenna element of the transmitting array antenna and the receiving antenna element of the receiving array antenna, which are in the arrangement relationship located in FIG. 1, the thickness of the dielectric layer is different. To do.

A wireless communication system according to an aspect of the present invention includes a transmission array antenna configured by a plurality of transmission antenna elements, and a reception array antenna configured by a plurality of reception antenna elements respectively facing the plurality of transmission antenna elements. A dielectric communication system comprising: a dielectric layer disposed between the transmitting array antenna and the receiving array antenna and having a relative dielectric constant that changes according to an applied electric field strength; and the dielectric layer A pair of electrodes for applying the electric field, a phase rotating unit for rotating the phase of the radio wave propagating in the dielectric layer according to the strength of the electric field, and each transmitting antenna of the transmitting array antenna A phase difference estimation unit for estimating a phase difference of a channel formed between an element and each reception antenna element of the reception array antenna, and the phase difference estimation unit. A phase difference adjustment unit that adjusts the phase difference of the channel so as to obtain a desired channel capacity by controlling a voltage between the pair of electrodes of the phase rotation unit based on the estimated phase difference. And the dielectric layer has a cavity formed along a first path between the transmitting antenna elements of the transmitting array antenna and the receiving antenna elements of the receiving array antenna that are in a mutually opposing arrangement relationship. And a structure in which a dielectric material is located in a second path between the transmitting antenna elements of the transmitting array antenna and the receiving antenna elements of the receiving array antenna, which are arranged in an oblique direction relative to each other, or A cavity is formed along the second path and a dielectric material is located in the first path.

A wireless communication system according to an aspect of the present invention includes a transmission array antenna configured by a plurality of transmission antenna elements, and a reception array antenna configured by a plurality of reception antenna elements respectively facing the plurality of transmission antenna elements. A dielectric communication system comprising: a dielectric layer disposed between the transmitting array antenna and the receiving array antenna and having a relative dielectric constant that changes according to an applied electric field strength; and the dielectric layer A pair of electrodes for applying the electric field, a phase rotating unit for rotating the phase of the radio wave propagating in the dielectric layer according to the strength of the electric field, and each transmitting antenna of the transmitting array antenna A phase difference estimation unit for estimating a phase difference of a channel formed between an element and each reception antenna element of the reception array antenna, and the phase difference estimation unit. A phase difference adjustment unit that adjusts the phase difference of the channel so as to obtain a desired channel capacity by controlling a voltage between the pair of electrodes of the phase rotation unit based on the estimated phase difference. And the dielectric layer has a first path between the transmitting antenna element of the transmitting array antenna and the receiving antenna element of the receiving array antenna, which are in a mutually opposing arrangement relationship, and oblique directions with respect to each other. The second path between the transmitting antenna element of the transmitting array antenna and the receiving antenna element of the receiving array antenna, which are in the arrangement relationship located in FIG. Features.

A wireless communication method according to an aspect of the present invention is a wireless communication method using the wireless communication system described above, in which the phase difference estimation unit is configured to transmit each of the transmission antenna elements of the transmission array antenna and the reception array antenna. A phase difference estimation step for estimating a phase difference of a channel formed between each receiving antenna element; and the phase difference adjustment unit is configured to perform the phase rotation based on the phase difference estimated in the phase difference estimation step. A phase difference adjusting step of adjusting a phase difference of the channel so as to obtain a desired channel capacity by controlling a voltage between the pair of electrodes included in the unit or a heat generation amount of the heat generating unit. Features.

  According to the present invention, when the transmission / reception interval deviates from the transmission / reception interval assumed at the time of designing the planar array antenna and the phase difference of each channel deviates from the phase difference when the channel capacity of short-distance MIMO transmission is maximized. However, the phase difference of each channel can be brought close to a desired phase difference when the channel capacity is maximized without changing the spacing of the antenna elements. Therefore, it is possible to suppress a decrease in channel capacity and to suppress deterioration in characteristics of short-distance MIMO transmission.

It is a block diagram which shows an example of schematic structure of the radio | wireless communications system in the 1st Embodiment of this invention. It is explanatory drawing which shows an example of a structure of the radome in the 1st Embodiment of this invention. It is explanatory drawing which shows an example of the path | route in the dielectric material layer of each channel in the 1st Embodiment of this invention. It is a flowchart which shows an example of the communication procedure of the 1st Embodiment of this invention. It is explanatory drawing which shows an example of a structure of the radome in the 2nd Embodiment of this invention. It is a flowchart which shows an example of the communication procedure of the 2nd Embodiment of this invention. It is explanatory drawing which shows an example of a structure of the radome in the 3rd Embodiment of this invention. It is explanatory drawing which shows an example of a structure of the radome in the 4th Embodiment of this invention. It is explanatory drawing which shows an example of a structure of the radome in the 5th Embodiment of this invention. It is explanatory drawing which shows an example of a structure of the radome in the 6th Embodiment of this invention. It is a block diagram which shows an example of schematic structure of the radio | wireless communications system in the 6th Embodiment of this invention. It is explanatory drawing which shows the example of arrangement | positioning of the antenna element in short distance MIMO transmission. It is a model figure of 2x2 short distance MIMO transmission.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In addition, the same code | symbol represents the same element over all embodiment and all drawings demonstrated below.

<First Embodiment>
[Description of configuration]
A configuration of the wireless communication system 1 according to the first embodiment of the present invention will be described.
FIG. 1 is a configuration diagram schematically showing an example of the configuration of the wireless communication system 1. The wireless communication system 1 includes a communication device 100 that functions as a transmitter and a communication device 700 that functions as a receiver. In 2 × 2 MIMO (two-input two-output MIMO) transmission, the communication device 100 communicates with the communication device 700. Data communication of two series (data series S1 and data series S2) is performed. Here, the communication device 100 transmits the data series S1 and S2, and includes transmission units 111 and 112, a plurality of transmission antenna elements 131 and 132, a radome 140, and a control device 150.

Among these, the transmission part 111 produces | generates the transmission signal of data series S1, and the transmission part 112 produces | generates the transmission signal of data series S2. The transmission antenna element 131 transmits the transmission signal of the data series S1 as a radio signal, and the transmission antenna element 132 transmits the transmission signal of the data series S2 as a radio signal. The radome 140 functions as a cover for protecting the transmission antenna elements 131 and 132, and also functions as a phase rotation unit that rotates the phase of each radio signal channel transmitted as a radio wave from the transmission antenna elements 131 and 132. Details thereof will be described later. Controller 150 functions as a phase difference adjusting section for adjusting a phase difference theta _H channel of the radio signal in the radome 140.

On the other hand, the communication device 700 is for receiving the data series S1 and S2, and includes receiving units 711 and 712, a weight calculation circuit 720, a plurality of receiving antenna elements 731 and 732, a radome 740, and a control device. 750 and a phase difference estimator 760. Among these, the radome 740 functions as a phase rotation unit that rotates the phase of the channel of the received radio signal, like the radome 140 described above. The receiving antenna elements 731 and 732 receive radio signals. The weight calculation circuit 720 performs signal separation by multiplying a reception signal obtained by receiving a radio signal by a reception weight. The receiving units 711 and 712 perform processing such as demodulation and decoding on the received signal. The control device 750 controls the phase difference between channels in the radome 740. The phase difference estimator 760 estimates the phase difference θ _H of the channel of the received signal and feeds back information about the phase difference θ _H to the communication apparatus 100.

Next, the configuration of the transmission antenna elements 131 and 132 and the reception antenna elements 731 and 732 will be described in detail.
In the present embodiment, the two transmission antenna elements 131 and 132 constituting the communication device 100 are arranged on the same plane with a distance d. Further, the two receiving antenna elements 731 and 732 constituting the communication device 700 are also arranged on the same plane with a distance d. The plane on which the transmission antenna elements 131 and 132 are arranged and the plane on which the reception antenna elements 731 and 732 are arranged are parallel to each other. The distance between the plane on which the transmitting antenna elements 131 and 132 are arranged and the plane on which the receiving antenna elements 731 and 732 are arranged, that is, the transmission / reception interval is D.

  Hereinafter, an antenna having a plurality of antenna elements arranged on the same plane is referred to as an array antenna. In the present embodiment, the transmission antenna element 131 and the transmission antenna element 132 constitute a transmission array antenna 130, and the reception antenna element 731 and the reception antenna element 732 constitute a reception array antenna 730. In addition, the reception antenna element 731 and the reception antenna element 732 are arranged at positions facing the transmission antenna element 131 and the transmission antenna element 132, respectively. Specifically, the reception antenna element 731 is disposed at a position facing the transmission antenna element 131, and the reception antenna element 732 is disposed at a position facing the transmission antenna element 132.

As described above, in the present embodiment, each of the communication device 100 and the communication device 700 includes two antenna elements. Therefore, the wireless communication system 1 performs data communication of two series (data series S1 and data series S2) from the communication apparatus 1 to the communication apparatus 2 in 2 × 2 MIMO (2-input 2-output MIMO) transmission. It is configured.
In addition, it is not limited to the above-mentioned example, The number of transmitting antenna elements and the number of receiving antenna elements corresponding to this are arbitrary.

Next, the configuration of the radomes (phase rotation units) 140 and 740 will be described with reference to FIG.
FIG. 2 is an explanatory diagram illustrating a configuration of the radome 140 included in the communication device 100 according to the first embodiment. In the present embodiment, the radome 140 having a function as a phase rotation unit is disposed in front of the transmission array antenna 130 so as to be positioned between the transmission array antenna 130 and the reception array antenna 730. The radome 140 includes a dielectric layer 1401 having a thickness T made of a liquid crystal whose relative dielectric constant changes according to the strength of the applied electric field, and a dielectric layer for applying the electric field to the dielectric layer 1401. A pair of electrodes 1402 and 1403 arranged on both surfaces of 1401 is provided, and the phase of the radio wave propagating in the dielectric layer 1401 is rotated according to the strength of the electric field. A radio signal (radio wave) transmitted from the transmission array antenna 130 is radiated to the propagation space after passing through the radome 140. The radome 740 is configured similarly to the radome 140.
The dielectric layer 1401 (7401) and the electrodes 1402 and 1403 (7402 and 7403) may be provided separately from the radome body.

  Similarly to the radome 140 described above, the radome 740 included in the communication device 700 includes a dielectric layer 7401 having a thickness T made of liquid crystal and a pair of electrodes 7402 and 7403 disposed on both surfaces of the dielectric layer 7401. Composed. The radome 740 is disposed in front of the reception array antenna 730, and a radio signal that has arrived at the communication device 700 from the communication device 100 passes through the radome 740 and is received by the reception array antenna 730.

  In the present embodiment, in the process in which the radio signal transmitted from each transmitting antenna element of the transmitting array antenna 130 is propagated to each receiving antenna of the receiving array antenna 730, the radome 140 is not affected. Electrodes 1402 and 1403 (7402 and 7403) are arranged on the dielectric layer 1401 (7401) of (740). For example, as shown in FIG. 2, electrodes 1402, 1403 (7402, 7403) are arranged on the outer periphery of the dielectric layer 1401 (7401). However, the present invention is not limited to this example, and the electrodes 1402 and 1403 (7402 and 7403) are limited to the extent that the signal strength of a radio signal required for communication can be obtained without hindering the function as the phase rotation unit. It may be arranged on the dielectric layer 1401 (7401) in any way.

[Description of operation]
Next, the operation of the wireless communication system 1 according to the present embodiment will be described.
In communication apparatus 100 functioning as a transmitter, transmission section 111 acquires data sequence S1, performs processing such as encoding and modulation, generates a transmission signal of data sequence S1, and outputs it to antenna element 131. Similarly, the transmission unit 112 acquires the data series S2, performs processing such as encoding and modulation, generates a transmission signal of the data series S2, and outputs the transmission signal to the antenna element 132. Here, the data series S1 and the data series S2 may be independent from each other or may be series having correlation.

  Subsequently, the transmission antenna element 131 transmits the transmission signal output from the transmission unit 111 as a radio signal (radio wave). Similarly, the transmission antenna element 132 transmits the transmission signal output from the transmission unit 112 as a radio signal (radio wave). These radio signals are incident on the radome 140.

In the radome 140, a voltage is applied between the electrode 1402 and the electrode 1403 of the dielectric layer 1401 under the control of the control device 150 that is performed based on phase difference information described later fed back from the phase difference estimation unit 760. The This voltage changes the relative dielectric constant ε _r of the liquid crystal of the dielectric layer 1401 in accordance with the strength of the electric field formed in the dielectric layer 1401 between the electrode 1402 and the electrode 1403. When the relative dielectric constant ε _r of the liquid crystal in the dielectric layer 1401 changes, the wavelength of the radio wave inside the dielectric layer 1401 changes. Here, assuming that the frequency of the radio wave used in the wireless communication system 1 is f ₀ and the free space wavelength is λ ₀ , the wavelength of the radio wave is reduced to 1 / √ε _r times in the dielectric layer 1401. Hereinafter, the wavelength of the radio wave in the dielectric layer 1401 is represented by the symbol λ. That is, the relationship λ = λ ₀ / √ε _r holds.

When the wavelength λ changes according to the relative dielectric constant ε _r of the liquid crystal of the dielectric layer 1401, the amount of phase rotation of a radio signal (radio wave) propagating through the thickness T of the dielectric layer 1401 changes. Therefore, by controlling the voltage (electric field strength) applied between the electrodes 1402 and 1403 and changing the relative permittivity ε _r of the liquid crystal forming the dielectric layer 1401, the transmitting array antenna 130 and the receiving array antenna are changed. The amount of phase rotation of the radio signal with respect to 730 can be changed, and the phase difference θ _H of the channel of the radio signal can be adjusted.

FIG. 3 is an explanatory diagram illustrating an example of a path in the dielectric layer of each channel according to the present embodiment and illustrating adjustment of the phase difference of the channel.
As shown in FIG. 3, the path P21 from the transmitting antenna element 131 to the receiving antenna element 732 forms an angle θ with respect to the path P11 from the antenna element 131 to the antenna element 731, and the propagation distance inside the dielectric layer 1401. Is T / cos θ (where 0 ° <θ <90 °). Therefore, the amount of phase rotation of the radio signal while propagating inside the dielectric layer 1401 (distance T) in the path P11 from the antenna element 131 to the antenna element 731 and the dielectric in the path P21 from the antenna element 131 to the antenna element 732 The difference from the phase rotation amount of the radio signal while propagating inside the body layer 1401 (distance T / cos θ) is T (1 / cos θ−1) / λ × 360 degrees.

Since the wavelength λ of the radio signal inside the dielectric layer 1401 changes according to the relative dielectric constant ε _r of the liquid crystal of the dielectric layer 1401, each path can be changed by changing the relative dielectric constant ε _r. It is possible to control the phase difference θ _H of the radio signal that passes through and reaches the receiving side. That is, the transmission / reception interval D deviates from the transmission / reception interval assumed in the design stage of the planar array antenna, and the channel phase difference θ _H deviates from the phase difference θ _H = 90 degrees at which the channel capacity of short-distance MIMO transmission is maximized. Even in this case, the channel phase difference θ _H can be brought close to 90 degrees without changing the distance d between the antenna elements.

On the other hand, in the radome 740 of the communication device 700, similarly to the radome 140 of the communication device 100 described above, under the control of the control device 750 performed based on phase difference information described later fed back from the phase difference estimation unit 760. The voltage (electric field strength) applied between the electrode 7402 and the electrode 7403 is controlled. As a result, the relative dielectric constant ε _r of the liquid crystal of the dielectric layer 7401 constituting the radome 740 is changed, and the phase difference θ _H of the channel of the radio signal arriving at the receiving antenna array 730 is brought close to 90 degrees.

Next, a description will be given feedback of the phase difference information to be used for adjusting the phase difference theta _H of the aforementioned channel.
Here, the channel matrix element h _ij between the transmission antenna elements TXA1 and TXA2 and the reception antenna elements RXA1 and RXA2 shown in FIG. 13 is used, and the channel from the transmission antenna element 131 to the reception antenna element 731 is used. The matrix element is h ₁₁ , the matrix element of the channel from the transmission antenna element 131 to the reception antenna element 732 is h ₂₁ , the matrix element of the channel from the transmission antenna element 132 to the reception antenna element 731 is h ₁₂ , and the reception is performed from the transmission antenna element 132. the matrix elements of the channel to the antenna element 732 is expressed as _{h 22.}

The phase difference estimation unit 760 of the communication apparatus 700 estimates a phase difference θ _H of a channel formed between each transmission antenna element of the transmission array antenna 130 and each reception antenna element of the reception array antenna 730. In the present embodiment, the phase difference estimation unit 760 estimates the phase difference θ _H from the relational expression θ _H = tan ⁻¹ (h ₂₁ / h ₁₁ ) = tan ⁻¹ (h ₁₂ / h ₂₂ ). Then, the phase difference estimation unit 760 feeds back the information of the estimated phase difference θ _{H to} the control device 150 and the control device 750 as phase difference information.

The control device 150 of the communication device 100 controls the voltage applied between the electrode 1402 and the electrode 1403 included in the radome 140 based on the channel phase difference information estimated by the phase difference estimation unit 760. Similarly, the control device 750 controls the voltage applied between the electrode 7402 and the electrode 7403 included in the radome 740 based on the phase difference information. Thus, control device 150 and control device 750 control the electric field strengths in dielectric layer 1401 and dielectric layer 7401, respectively, and feedback control the phase difference θ _{H of the} channel so that a desired channel capacity can be obtained. To do.

In the present embodiment, the communication device 100, before transmitting the data sequence S1 and data sequence S2, and transmits a training signal for estimating a phase difference theta _H channel. Then, the phase difference estimation unit 760 of the communication device 700 uses the information of the phase difference θ _H estimated using the training signal transmitted from the communication device 100 as the above-described phase difference information and the control device 150 of the communication device 100 and the communication device. Feedback is made to the control device 750 of 700. Based on the information on the phase difference θ _H fed back from the phase difference estimation unit 760, the control device 150 and the control device 750 cause the electrode 1402 and the electrode 1403 of the radome 140 so that the phase difference θ _H approaches 90 degrees. And the voltage (electric field strength) between the electrodes 7402 and 7403 of the radome 740 are controlled.
Note that means and a method for feeding back the phase difference information estimated by the phase difference estimating unit 760 of the communication device 700 to the control device 150 of the communication device 100 are TDD (time division duplex), FDD (frequency division duplex), and the like. Any means and techniques can be used and are not limited to any particular means.

Subsequently, the communication apparatus 700 extracts each series of data from the radio signal received from the communication apparatus 100 as described below.
Each of the reception antenna element 731 and the reception antenna element 732 is a radio signal obtained by combining a radio signal transmitted from the transmission antenna element 131 and a radio signal transmitted from the transmission antenna element 132 and both radio signals. And output to the weight calculation circuit 720. That is, the reception antenna element 731 receives a radio signal obtained by combining the radio signal transmitted from the transmission antenna element 131 and the radio signal transmitted from the transmission antenna element 132. The reception antenna element 732 also receives a radio signal obtained by combining the radio signal transmitted from the transmission antenna element 131 and the radio signal transmitted from the transmission antenna element 132.

  The weight calculation circuit 720 performs signal separation by multiplying the signal received by the reception antenna element 731 and the signal received by the reception antenna element 732 by the reception weight. Then, the weight calculation circuit 720 obtains a signal of the sequence S1 ′ corresponding to the signal of the sequence S1 transmitted by the transmitting antenna element 131 by the above signal separation, and outputs the signal of the sequence S1 ′ to the receiving unit 711. . Further, the weight calculation circuit 720 obtains a signal of the sequence S2 ′ corresponding to the signal of the data sequence S2 transmitted by the transmitting antenna element 132 by the signal separation described above, and outputs the signal of the sequence S2 ′ to the receiving unit 712. To do.

The receiving unit 711 performs a process such as demodulation and decoding on the signal of the sequence S1 ′ output from the weight calculation circuit 720, and generates a data sequence S1 ′. The receiving unit 712 performs processing such as demodulation and decoding on the signal of the sequence S2 ′ output from the weight calculation circuit 720 to generate a data sequence S2 ′.
As described above, the data sequences S1 and S2 transmitted from the communication device 100 on the transmission side are restored as the data sequences S1 ′ and S2 ′ in the communication device 700 on the reception side.

Next, with reference to the flowchart of FIG.
First, in step S101, the communication apparatus 100 transmits a training signal before transmitting radio signals of the data series S1 and the data series S2. Subsequently, in step S102, the communication device 700 receives a training signal transmitted from the communication device 100, a phase difference estimation unit 760, after estimating the phase difference theta _H of each channel, information of the phase difference theta _H Is fed back to the control devices 150 and 750 as phase difference information.

Subsequently, in step S103, the control devices 150 and 750, based on the fed back phase difference information, the voltage (electric field strength) applied between the electrode 1402 and the electrode 1403 of the radome 140 and the electrode 7402 of the radome 740. And the voltage (electric field strength) applied between the antenna 7403 and the electrode 7403 are controlled so that the channel phase difference θ _H between the antenna elements approaches 90 degrees. Subsequently, in step S104, after the adjustment of the phase difference theta _H above, the communication apparatus 100 starts transmission of a radio signal data series S1 and data sequence S2.

In the configuration of FIG. 1, the communication device 100 on the transmission side and the communication device 700 on the reception side are each provided with a radome 140 and a radome 740, and the relative permittivity of the dielectric layer constituting the radome on both the transmission side and the reception side is set. However, only one of the communication device 100 and the communication device 700 may include a radome, and the relative dielectric constant of the dielectric layer may be controlled.
Further, in the present embodiment has described the case of estimating the phase difference theta _H of each channel using a training signal for estimating a phase difference theta _H channel, the phase difference of each channel without using a training signal You may use what is called blind estimation which estimates (theta) _H.
Furthermore, in the present embodiment, the channel phase difference θ _H is close to 90 degrees, but the present invention is not limited to this, and the channel phase difference θ _H may be close to any desired value. The same applies to other embodiments described later.

<Second Embodiment>
Next, a second embodiment of the present invention will be described.
For simplification of description, elements common to the first embodiment and the apparatus configuration will be described with reference to the reference numerals shown in FIG.

  In the first embodiment described above, the relative dielectric constant of the liquid crystal constituting the dielectric layer 1401 and the dielectric layer 7401 is controlled by the applied electric field strength. The relative dielectric constant of this dielectric layer is the dielectric layer. It can also be controlled by changing the temperature. Therefore, in the second embodiment, the relative dielectric constant of the dielectric layer constituting the radome is controlled by temperature. Therefore, the radio communication system according to the present embodiment replaces each of the radomes 140 and 740 with the radome 240 shown in FIG. 5 in the configuration of the radio communication system 1 according to the first embodiment shown in FIG. It has a device configuration. In the present embodiment, the control units 150 and 750 are different from the first embodiment in that the amount of heat generated by the heat generating unit 2402 is controlled.

  Specifically, the wireless communication system according to the present embodiment includes a radome 240 instead of each of the radomes 140 and 740 in the configuration of the first embodiment shown in FIG. The radome 240 is disposed between the transmitting array antenna 130 and the receiving array antenna 730, and applies a temperature to the dielectric layer 2401 whose relative dielectric constant changes according to the applied temperature, and the dielectric layer 2401. And a heat generating part 2402 for functioning as a phase rotating part for rotating the phase of the radio wave propagating through the dielectric layer 2401 in accordance with the heat generating temperature of the heat generating part 2402. Further, in the present embodiment, the control devices 150 and 750 control the heat generation amount of the heat generating unit 2402 included in the radome 240 based on the phase difference estimated by the phase difference estimating unit 760, thereby obtaining a desired channel capacity. It functions as a phase difference adjusting unit that adjusts the phase difference of the channel so as to be obtained. Other apparatus configurations are the same as those of the first embodiment.

FIG. 5 is an explanatory diagram illustrating the configuration of the radome 240 included in each communication device that configures the wireless communication system according to the second embodiment.
The radome 240 provided in each communication device on the transmission side and the reception side includes a dielectric layer 2401 and a heat generating portion (temperature variable portion) 2402 having a variable heat generation temperature. In the present embodiment, the heat generating portion 2402 is attached to one surface side of the dielectric layer 2401. However, the heat generating portion 2402 may be attached to both surfaces of the dielectric layer 2401 without being limited to this example.
For simplification of description, the radome included in the communication device on the transmission side and the radome included in the communication device on the reception side are represented by reference numeral 240, but the radomes included in the communication devices on the transmission side and the reception side are separated. Elements.

  A radome 240 included in the transmission-side communication device is disposed in front of the transmission array antenna 130 of FIG. The radio signal transmitted from the transmission array antenna 130 is radiated to the propagation space after passing through the inside of the radome 240. Similarly, the radome 240 included in the communication device on the reception side is disposed in front of the reception array antenna 730 in FIG. A radio signal that has arrived at the communication device on the reception side passes through the inside of the radome 240 of the communication device on the reception side and is received by the reception array antenna 730 shown in FIG.

In the radome 240 on the transmission side, the relative dielectric constant ε _{r of the} dielectric layer 1 changes according to the temperature set by the control device 150. As described in the first embodiment, the amount of phase rotation of a radio signal (radio wave) propagating in the dielectric layer 2401 changes according to the relative permittivity ε _r . Therefore, by controlling the heat generation amount of the heat generating part 2402, the temperature of the dielectric layer 2401 is controlled and the relative dielectric constant ε _r of the dielectric layer 2401 is changed. Thus, it is possible to control the phase difference theta _H channel of the radio signal incoming to the communication apparatus on the receiving side through the respective paths, the phase difference theta _H of each channel without changing the spacing d of the antenna elements 90 It becomes possible to approach the degree.

On the other hand, in the radome 240 included in the communication device on the reception side, the temperature of the dielectric layer 2401 is controlled by controlling the amount of heat generated by the heat generating portion 2402, as in the radome 240 included in the communication device on the transmission side. The relative dielectric constant ε _r of 2401 is changed. Thus, approximating the phase difference theta _H of each channel 90 degrees.

Based on the information of the phase difference θ _H = tan ⁻¹ (h ₂₁ / h ₁₁ ) = tan ⁻¹ (h ₁₂ / h ₂₂ ) of each channel, the transmission side control device and the reception side control device respectively. The temperature of the dielectric layer 2401 of the transmitting radome 240 and the temperature of the dielectric layer 2401 of the receiving radome 240 are controlled. More specifically, the transmission-side communication device transmits a training signal for estimating the channel phase difference θ _H before transmitting the data sequence S1 and the data sequence S2. The phase difference estimation unit 760 of the reception side communication apparatus estimates the channel phase difference θ _H using the training signal transmitted from the transmission side communication apparatus, and uses the estimated phase difference θ _H as the estimated phase difference. Information is fed back to the control device 150 of the communication device on the transmission side and the control device 750 of the communication device on the reception side. Controller 750 of the control unit 150 and the reception side of the transmission side, based on the information of the feedback from the phase difference estimation unit 760 phase difference theta _H, as the phase difference theta _H approaches 90 degrees, the heat generating portion 2402 The amount of heat generated is controlled, and the temperature of the dielectric layer 2401 is controlled.

  Next, with reference to the flowchart of FIG. 6, the operation procedure of the wireless communication system according to the present embodiment will be comprehensively described. Basically, the second embodiment is the same as the first embodiment except that the relative permittivity of the dielectric layer constituting the radome included in each communication device on the transmission side and the reception side is controlled by temperature.

First, in step S201, the communication device on the transmission side transmits a training signal before transmitting radio signals of the data series S1 and the data series S2. Subsequently, in step S202, the receiving-side communication device receives the training signal transmitted from the transmitting-side communication device, the phase difference estimation unit 760, after estimating the phase difference theta _H of each channel, the phase difference information theta _H is fed back to the control unit 750 of the transmitting side and the receiving side control unit 150 as a phase difference information.

Subsequently, in step S203, the control devices 150 and 750 control the heat generation amount of the heat generating portion 2402 of each radome 240 included in the communication device on the reception side and the transmission side based on the fed back phase difference information, and each antenna The phase difference θ _H of the channel between elements is brought close to 90 degrees. Subsequently, in step S204, after the adjustment of the phase difference theta _H above, the communication apparatus on the transmission side starts the transmission of the wireless signal of the data sequence S1 and data sequence S2.

As in the first embodiment, only one of the communication device on the transmission side or the communication device on the reception side may include the radome 240 and control the relative dielectric constant of the dielectric layer.
Similarly to the first embodiment, the algorithm for estimating the phase difference θ _{H of the} channel may be blind estimation that does not use a training signal.

<Third Embodiment>
Next, a third embodiment of the present invention will be described.
In the first embodiment and the second embodiment described above, the shape of the radomes 140, 740, 240 is a flat plate, and the relative dielectric constant of the dielectric layer of the flat radome is controlled. In the third embodiment, the phase difference θ _H of the channel is adjusted by processing the shape of the dielectric layer constituting the radome into a shape other than the flat plate shape. In the present embodiment, a radome composed of a dielectric layer having a thicker shape in an oblique direction as compared to the front direction of the antenna element is used. Except for the configuration relating to the shape of the dielectric layer constituting the radome, the configuration of the wireless communication system according to the present embodiment is the same as that of the first or second embodiment described above.

  FIG. 7 is an explanatory diagram illustrating a configuration of a radome 340 included in the wireless communication system according to the third embodiment. As shown in FIG. 7, regarding the thickness of the dielectric layer 3401 constituting the radome 340, the thickness of the portions 3402, 3403 located in the front direction of the transmitting antenna elements 131, 132 is Ta, When the thickness of the dielectric layer 3401 is T, the relationship of T> Ta is established. That is, the dielectric layer 3401 has a shape in which the thickness Ta in the front direction of the antenna element is set smaller than the thickness T of other portions.

  In such a configuration, the dielectric layer 3401 in the path toward the oblique direction of the transmission antenna element, that is, the path P21 from the transmission antenna element 131 to the reception antenna element 732 or the path 12 from the transmission antenna element 132 to the reception antenna element 731. The internal propagation distance is T / cos θ. Here, θ is an angle between the route P11 and the route P21, or an angle between the route P22 and the route P12, and takes a value in a range of 0 ° <θ <90 °. Further, the propagation distance inside the dielectric layer 3401 in the path in the front direction of the antenna element, that is, the path P11 from the transmission antenna element 131 to the reception antenna element 731 or the path P22 from the transmission antenna element 132 to the reception antenna element 732 is Ta It is.

Therefore, the phase rotation amount of the radio signal propagating through the dielectric layer 3401 in the path in the front direction of the transmitting antenna element and the phase of the radio signal propagating through the dielectric layer 3401 in the path in the oblique direction of the transmission antenna element The difference from the rotation amount is (T / cos θ−Ta) / λ × 360 degrees. Here, since T> Ta, the difference in phase rotation amount T (1 / cos θ−1) / λ × 360 degrees due to the radomes 140, 240, and 740 in the first and second embodiments described above. a large value, the greater the change in the phase difference theta _H of each path due to the change in the relative dielectric constant epsilon _r of the dielectric layer 3401. Therefore, according to the present embodiment, than the case of using a flat radome in the first embodiment and the second embodiment, it is possible to make the phase difference theta _H more 90 degrees.

  As described above, the dielectric layer 3401 according to the present embodiment is positioned obliquely with respect to the first path (for example, the path P11) between the transmitting antenna element and the receiving antenna element that are in a mutually opposing arrangement relationship. In the second path (for example, path P21) between the transmitting antenna element and the receiving antenna element in the arrangement relationship, the thickness of the dielectric layer 3401 is different.

  In the present embodiment, as shown in FIG. 7, a case where a radome 340 composed of a dielectric layer 3401 having a thicker shape is used in an oblique direction as compared to the front direction of the transmitting antenna element will be described. However, the present invention is not limited to this example, and the thickness in the front direction compared to the oblique direction of the transmitting antenna element is limited, as long as the phase difference of the channel can be adjusted so as to suppress the decrease in channel capacity. The shape may be large. Further, the radome 340 formed of the dielectric layer 3401 having a shape having two types of thicknesses (T and Ta) according to the positional relationship between the transmitting antenna element and the receiving antenna element has been described. The number of types of the thickness is arbitrary as long as the thickness of the element has a difference between the thickness in the front direction and the thickness in the oblique direction.

<Fourth Embodiment>
Next, a fourth embodiment of the present invention will be described.
In the first to third embodiments described above, the dielectric layer also exists in the front direction of the transmitting antenna element, and the radio signal propagates through the dielectric layer in the process of arrival of the radio signal at the opposing receiving antenna element. However, in the fourth embodiment, a radome composed of a dielectric layer having a shape in which no dielectric material exists only in the front direction of the transmitting antenna element (that is, the receiving antenna element) is used. explain. Other configurations are the same as those in the first to third embodiments.

FIG. 8 is an explanatory diagram showing the configuration of the radome 440 in the fourth embodiment.
As shown in FIG. 8A, in the front direction of the transmission antenna elements 131 and 132, that is, the path P11 from the antenna element 131 to the reception antenna element 731 and the path P22 from the transmission antenna element 132 to the reception antenna element 732, Cavities 4402 and 4403 are formed in the dielectric layer 4401 constituting the radome 440. As shown in FIG. 8B, the cavities 4402 and 4403 are formed as through holes penetrating from one surface of the dielectric layer 4401 to the other surface. The radio signals transmitted from the transmitting antenna element 131 and the transmitting antenna element 132 propagate through the space in the cavity without propagating through the dielectric material forming the dielectric layer 4401, respectively, and receive antenna element 731 and Arrives at the receiving antenna element 732.

On the other hand, similarly to the first to third embodiments described above, the oblique direction of the transmission antenna element, that is, the path P21 from the transmission antenna element 131 to the reception antenna element 732, or the transmission antenna element 132 to the reception antenna element 731. The propagation distance of the radio signal inside the dielectric layer 4401 in the path P22 is T / cos θ (where 0 degree <θ <90 degrees).
Accordingly, the amount of phase rotation of the radio signal changes only in the oblique direction of the antenna element due to the change in the relative dielectric constant ε _r of the dielectric layer 4401, so that compared to the case where the radome in the first to third embodiments is used. , change in the phase difference theta _H channels of each path is also increased, the phase difference theta _H of the channel more can be close to 90 degrees.

  As described above, the dielectric layer 4401 according to the present embodiment has a cavity (for example, a cavity) along the first path (for example, the path P11) between the transmitting antenna element and the receiving antenna element that are in a mutually opposing arrangement relationship. 4402) and a structure in which the dielectric material is positioned in the second path (for example, path P21) between the transmitting antenna element and the receiving antenna element that are disposed in an oblique direction relative to each other.

  In the present embodiment, as shown in FIG. 8, the case where a radome 440 including a dielectric layer 4401 having a shape in which a cavity is formed only in the front direction of the transmitting antenna elements 131 and 132 has been described. However, a dielectric layer having a shape in which a cavity is formed only in an oblique direction of the antenna element may be used as long as the phase difference of the channel can be adjusted so that a decrease in channel capacity is suppressed. That is, the dielectric layer 4401 according to the present embodiment has a cavity (not shown) along the second path (for example, path P21) between the transmitting antenna element and the receiving antenna element that are disposed in an oblique direction with respect to each other. ) And a structure in which a dielectric material is located in a first path (for example, path P11) between the transmitting antenna element and the receiving antenna element that are in a mutually opposing arrangement relationship.

<Fifth Embodiment>
Next, a fifth embodiment of the present invention will be described.
In the third embodiment described above, the case where the radome 340 including the dielectric layer 3401 having a shape with different thicknesses according to the positional relationship between the transmitting antenna element and the receiving antenna element is described. In the embodiment, the case where the radome 440 including the dielectric layer 4401 having the shape in which the cavity where the dielectric material does not exist is formed only in either the front direction or the oblique direction of the transmitting antenna element has been described. In the fifth embodiment, a case will be described in which a radome having a dielectric layer composed of different types of dielectric materials is used in the front direction and the oblique direction of the transmitting antenna element. About another structure, it is the same as that of the above-mentioned 3rd or 4th embodiment.

FIG. 9 is an explanatory diagram illustrating a configuration of a radome 540 according to the fifth embodiment.
As shown in FIG. 9, the radome 540 includes a dielectric layer made of a dielectric material 5402 (relative permittivity ε _r1 ) in the front direction of the transmitting antenna element, that is, in the path P21 from the transmitting antenna element 131 to the receiving antenna element 731. In the path P22 from the transmitting antenna element 132 to the receiving antenna element 732, a dielectric layer made of a dielectric material 5403 (relative permittivity ε _r1 ) is provided. In addition, the radome 540 has a dielectric material 5401 (relative permittivity) in an oblique direction of the antenna element, that is, a path P21 from the transmitting antenna element 131 to the receiving antenna element 732 and a path P12 from the transmitting antenna element 132 to the receiving antenna element 732. a dielectric layer made of ε _r2 ).

Here, the dielectric material 5402 and the dielectric material 5403 are the same type of dielectric material, and these dielectric materials 5402 and 5403 are different in type from the dielectric material 5401 (that is, the relative dielectric constant is higher). Different materials). In this embodiment, two types of dielectric materials that are different between the front direction and the oblique direction of the transmitting antenna element are used, and the relative dielectric constant of these dielectric materials is changed, so that the channel position between the antenna elements is changed. the phase difference theta _H adjusted to be closer to 90 degrees.

As described above, the dielectric layer included in the radome 540 according to the present embodiment is inclined with respect to the first path (for example, the path P21) between the transmitting antenna element and the receiving antenna element that are in a mutually opposing arrangement relationship. The second path (for example, path P21) between the transmitting antenna element and the receiving antenna element in the arrangement relationship positioned in the direction is made of a dielectric material having a different relative dielectric constant. According to the present embodiment, if the relative dielectric constant of each dielectric material is selected, the channel phase difference θ _H is made closer to 90 degrees compared to the third or fourth embodiment described above. It becomes possible to adjust.

<Sixth Embodiment>
Next, a sixth embodiment of the present invention will be described.
In the first to fifth embodiments described above, the phase difference θ _H of the channel between the antenna elements is adjusted by changing the relative dielectric constant ε _r of the dielectric layer constituting the radome. In the sixth embodiment, even when the transmission / reception interval D deviates from the transmission / reception interval assumed in the design stage of the planar array antenna, the dielectric layer does not change the relative permittivity ε _r, and does not change. The phase difference θ _{H of the} channel is prevented from deviating from 90 degrees.

  FIG. 10 is an explanatory diagram showing the configuration of the radome 640 in the sixth embodiment. The dielectric layers 6401 and 6402 constituting the radome 640 have curved surfaces determined from the relationship among the transmission / reception interval D, the element interval d, the wavelength λ inside the dielectric layer of the radio wave, and the angle θ from the antenna element. It has a shape to include.

Hereinafter, the configuration of the curved surface of the dielectric layers 6401 and 6402 will be described.
When an array antenna having a certain antenna element interval d is used, if the transmission / reception interval D changes, the phase difference θ _H of the channel between the antenna elements deviates from the optimum 90 degrees at which the channel capacity becomes maximum, and The path between the transmitting and receiving antenna elements located in the oblique direction also changes. That is, the angle of the direction when viewing the receiving antenna element from the transmitting antenna element changes, and therefore, the propagation path of the radio signal inside the dielectric layer changes.

Therefore, in this embodiment, the dielectric layers 6401 and 6402 constituting the radome 640 transmit antenna elements such that the phase difference θ _{H of} each channel is constant at 90 degrees even when the transmission / reception interval D changes. The propagation distance of the radio signal inside the dielectric layer varies depending on the angle θ in the direction of viewing the receiving antenna element. As a result, even when the transmission / reception interval D changes, the radio signal arrives at the receiving antenna element through a path where the phase difference θ _{H of} each channel is 90 degrees. Therefore, the first to fifth embodiments are different from the first to fifth embodiments. Unlike, without changing the relative dielectric constant epsilon _r of the dielectric layer may correspond to a deviation of the reception interval D.

In the example shown in FIG. 10, when the transmission / reception interval D changes, for example, the angle θ in the direction of viewing the receiving antenna element 732 from the transmitting antenna element 131 changes. In accordance with the change in the angle θ, for example, the propagation path length Tx of the radio signal inside the dielectric layer 6401 on the path P21 from the transmitting antenna element 131 toward the receiving antenna element 732 in the oblique direction depends on the shape of the curved surface. The phase difference θ _{H of} each channel changes so as to be 90 degrees. Thus, transmission and reception interval D be varied, the phase difference theta _H channels are maintained at 90 degrees, a decrease in channel capacity can be prevented.

FIG. 11 is a configuration diagram illustrating a schematic configuration of the wireless communication system according to the present embodiment. In the wireless communication system according to the present embodiment, in the configuration of the first embodiment illustrated in FIG. 1 described above, the communication device 100 functioning as a transmitter includes a radome 640 illustrated in FIG. 10 instead of the radomes 140 and 740. . The communication device 700 functioning as a receiver includes a radome 764. This radome 764 basically has a curved surface in which the channel phase difference θ _H is maintained at 90 degrees, like the radome 640. It is comprised from the dielectric material layer which has.

As described above, the radio communication system according to the present embodiment includes the radomes 640 and 764 made of the dielectric layer disposed between the transmission array antenna and the reception array antenna, and the dielectric layer is configured to be connected to the transmission array antenna and the reception array antenna. With respect to the change in the transmission / reception interval D with the array antenna, the channel phase difference θ _H formed between each transmitting antenna element of the transmitting array antenna and each receiving antenna element of the receiving array antenna is expressed as the channel capacity. It has a shape including a curved surface formed so as to keep a substantially constant phase difference (for example, 90 degrees) to be maximized.

According to the present embodiment, since it is not necessary to control the relative permittivity ε _r of the radomes 640 and 764, it is not necessary to include the control devices 150 and 750 and the phase difference estimation unit 760 as shown in FIG. The configuration of the communication system can be simplified. About others, it is the same as that of 1st Embodiment.

  In the first to sixth embodiments of the present invention described above, the present invention has been described as a wireless communication system, but the present invention can also be expressed as a wireless communication method. In this case, the present invention provides, as a wireless communication method corresponding to the wireless communication systems of the first to fifth embodiments described above, for example, a transmission array antenna composed of a plurality of transmission antenna elements, and the plurality of transmission antennas. A receiving array antenna composed of a plurality of receiving antenna elements respectively facing the element, and disposed between the transmitting array antenna and the receiving array antenna, and having a relative dielectric constant according to the strength or temperature of an applied electric field A dielectric layer that changes and a pair of electrodes for applying the electric field to the dielectric layer, or a heating part for applying the temperature to the dielectric layer, and depending on the strength of the electric field or the temperature A wireless communication method using a wireless communication system, comprising: a phase rotation unit that rotates a phase of a radio wave propagating in the dielectric layer, wherein the transmission array A phase difference estimation step for estimating a phase difference of a channel formed between each transmission antenna element of the tenor and each reception antenna element of the reception array antenna, and based on the phase difference estimated in the phase difference estimation step A phase difference adjusting step of adjusting a phase difference of the channel so as to obtain a desired channel capacity by controlling a voltage between the pair of electrodes included in the phase rotating unit or a heat generation amount of the heat generating unit; , And can be expressed as a wireless communication method.

  In addition, the present invention provides, as a wireless communication method corresponding to the wireless communication system of the sixth embodiment described above, for example, a transmission array antenna composed of a plurality of transmission antenna elements, and a plurality of transmission antenna elements facing each other. A receiving array antenna comprising a plurality of receiving antenna elements, and a dielectric layer disposed between the transmitting array antenna and the receiving array antenna, and rotating a phase of a radio wave propagating through the dielectric layer A wireless communication method using a wireless communication system including a phase rotating unit to be formed between each transmitting antenna element of the transmitting array antenna and each receiving antenna element of the receiving array antenna by the phase rotating unit. Controlling the phase difference between channels, wherein the dielectric layer comprises the transmitting array antenna and the receiving array antenna. The phase difference between the channels formed between the transmitting antenna elements of the transmitting array antenna and the receiving antenna elements of the receiving array antenna is a measure for maximizing the channel capacity. It can be expressed as a wireless communication method characterized by having a shape including a curved surface that maintains a constant phase difference.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and can be arbitrarily modified or modified without departing from the gist of the present invention.
For example, in the above-described embodiment, the case where liquid crystal is used as the dielectric layer has been described. However, the present invention is not limited to this example, and any type can be used as long as it can be controlled by changing the relative dielectric constant. Dielectric materials may be used.
In the above-described embodiment, the communication device 100 is described as a transmitter and the communication device 700 is described as a receiver. However, each of the communication devices 100 and 700 is configured as a transceiver having both a transmission function and a reception function. Also good.

  DESCRIPTION OF SYMBOLS 1 ... Wireless communication system, 100, 700 ... Communication apparatus, 111, 112 ... Transmission part, 130 ... Transmission array antenna, 131, 132 ... Transmission antenna element, 140, 240, 340, 440, 540, 640, 740, 764 ... Radome, 150, 750... Control device, 711, 712. Receiving unit, 720. Weight calculating circuit, 730. Receiving array antenna, 731, 732. Receiving antenna element, 760.

Claims (5)

A wireless communication system comprising: a transmission array antenna composed of a plurality of transmission antenna elements; and a reception array antenna composed of a plurality of reception antenna elements respectively facing the plurality of transmission antenna elements,
A dielectric layer that is disposed between the transmitting array antenna and the receiving array antenna and has a relative dielectric constant that changes according to an applied temperature, and a heat generating unit that applies the temperature to the dielectric layer. A phase rotation unit that rotates the phase of the radio wave propagating in the dielectric layer according to the temperature;
A phase difference estimation unit that estimates a phase difference of a channel formed between each transmission antenna element of the transmission array antenna and each reception antenna element of the reception array antenna;
Based on the phase difference estimated by the phase difference estimation unit, the phase difference of the channel is adjusted to obtain a desired channel capacity by controlling the amount of heat generated by the heat generation unit of the phase rotation unit. And a phase difference adjustment unit. A wireless communication system comprising: a transmission array antenna composed of a plurality of transmission antenna elements; and a reception array antenna composed of a plurality of reception antenna elements respectively facing the plurality of transmission antenna elements,
A dielectric layer disposed between the transmitting array antenna and the receiving array antenna and having a relative permittivity that changes in accordance with an applied electric field strength, and a pair of electrodes for applying the electric field to the dielectric layer A phase rotation unit that rotates the phase of the radio wave propagating in the dielectric layer according to the strength of the electric field,
A phase difference estimation unit that estimates a phase difference of a channel formed between each transmission antenna element of the transmission array antenna and each reception antenna element of the reception array antenna;
Based on the phase difference estimated by the phase difference estimation unit, by controlling the voltage between the pair of electrodes of the phase rotation unit, the phase difference of the channel is adjusted so that a desired channel capacity is obtained. A phase difference adjustment unit to be adjusted;
Comprising
The dielectric layer is
A first path between a transmitting antenna element of the transmitting array antenna and a receiving antenna element of the receiving array antenna that are in a mutually opposing arrangement relationship, and the transmitting array antenna that is in an oblique relation to each other. in the second path between the receiving antenna elements of the transmitting antenna element and the receiving array antennas, radio communications systems that wherein the thickness of the dielectric layer have different shapes. A wireless communication system comprising: a transmission array antenna composed of a plurality of transmission antenna elements; and a reception array antenna composed of a plurality of reception antenna elements respectively facing the plurality of transmission antenna elements,
A dielectric layer disposed between the transmitting array antenna and the receiving array antenna and having a relative permittivity that changes in accordance with an applied electric field strength, and a pair of electrodes for applying the electric field to the dielectric layer A phase rotation unit that rotates the phase of the radio wave propagating in the dielectric layer according to the strength of the electric field,
A phase difference estimation unit that estimates a phase difference of a channel formed between each transmission antenna element of the transmission array antenna and each reception antenna element of the reception array antenna;
Based on the phase difference estimated by the phase difference estimation unit, by controlling the voltage between the pair of electrodes of the phase rotation unit, the phase difference of the channel is adjusted so that a desired channel capacity is obtained. A phase difference adjustment unit to be adjusted;
Comprising
The dielectric layer is
An arrangement in which a cavity is formed along a first path between the transmission antenna element of the transmission array antenna and the reception antenna element of the reception array antenna that are in an arrangement relationship facing each other, and is positioned obliquely to each other A structure in which a dielectric material is located in a second path between the transmitting antenna element of the transmitting array antenna and the receiving antenna element of the receiving array antenna, or a cavity is formed along the second path radio communications system that is characterized by having any of the structures of the structure dielectric material to said first path is positioned with. A wireless communication system comprising: a transmission array antenna composed of a plurality of transmission antenna elements; and a reception array antenna composed of a plurality of reception antenna elements respectively facing the plurality of transmission antenna elements,
A dielectric layer disposed between the transmitting array antenna and the receiving array antenna and having a relative permittivity that changes in accordance with an applied electric field strength, and a pair of electrodes for applying the electric field to the dielectric layer A phase rotation unit that rotates the phase of the radio wave propagating in the dielectric layer according to the strength of the electric field,
A phase difference estimation unit that estimates a phase difference of a channel formed between each transmission antenna element of the transmission array antenna and each reception antenna element of the reception array antenna;
Based on the phase difference estimated by the phase difference estimation unit, by controlling the voltage between the pair of electrodes of the phase rotation unit, the phase difference of the channel is adjusted so that a desired channel capacity is obtained. A phase difference adjustment unit to be adjusted;
Comprising
The dielectric layer is
A first path between a transmitting antenna element of the transmitting array antenna and a receiving antenna element of the receiving array antenna that are in a mutually opposing arrangement relationship, and the transmitting array antenna that is in an oblique relation to each other. the second and the route radio communications system that is characterized in that the dielectric constant is composed of different kinds of dielectric material between the transmitting antenna elements and receiving antenna elements of the receiving array antenna. A wireless communication method using the wireless communication system according to any one of claims 1 to 4 ,
Wherein the phase difference estimating section, a phase difference estimation step of estimating the phase difference between the channels formed between each receive antenna elements for each transmit antenna element and the receiving array antenna of the transmission array antenna,
The phase difference adjustment unit controls the voltage between the pair of electrodes of the phase rotation unit or the heat generation amount of the heat generation unit based on the phase difference estimated in the phase difference estimation step, A phase difference adjustment step of adjusting the phase difference of the channels so that a channel capacity of
A wireless communication method comprising:

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