JP6235991B2 - 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, with the increase in communication volume, 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 at the same time from a plurality of transmission antennas at the same time, and each signal is processed by signal processing on the receiver side by using a multipath environment between the transmitter and the receiver. Separate 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 transmission antenna and the reception antenna are arranged close to each other, and the environment between the transmitter and the receiver is not a multipath environment. It is attracting attention that MIMO transmission technology is applicable. 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, by appropriately setting the element spacing in the array antenna in accordance with the distance between the transmitter and the receiver, even in a case where the multipath environment is not used. The spatial correlation between the antennas 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 1 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.

  Currently, a non-contact high-speed transfer system that applies high-speed download of large-capacity content from an information terminal (for example, a so-called kiosk terminal) to a mobile terminal by applying the above-described short-distance MIMO transmission to millimeter wave communication is being studied. In this non-contact high-speed transfer system, the antenna becomes small by using the millimeter wave band, so that a plurality of antenna elements can be mounted on a small terminal.

FIG. 10 is an explanatory diagram showing an arrangement example of antenna elements in short-range MIMO transmission. In FIG. 13, the number of transmission antenna elements Tx _j (j is a natural number of 1 ≦ j ≦ M and M is a natural number of M ≧ 2) constituting the array antenna TXA on the transmission side, and the reception side The number of receiving antenna elements Rx _i (i is a natural number of 1 ≦ i ≦ M) constituting each array antenna RXA is M. The transmitting antenna element Tx _j is arranged on the plane PT, and the receiving antenna element Rx _i is opposed to the transmitting antenna element Tx _j across the propagation space FS on the plane PR parallel to the plane PT. Is arranged. 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. 11 is a model diagram of 2 × 2 short-range MIMO transmission. In the 2 × 2 short-distance MIMO transmission shown in FIG. 11, the channel matrix H of the propagation path between the transmitting antenna elements Tx ₁ and Tx ₂ and the receiving antenna elements Rx ₁ and Rx ₂ is expressed by Expression (1). The signals r ₁ and r ₂ are expressed by Expression (2).

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

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

In Expressions (3) and (4), the matrix element w _ij (where i and j are natural numbers less than or equal to 2) is the data series s corresponding to the data series S ′ transmitted by the transmission antenna element Tx _i . 'Indicates a weight by which a signal received by the receiving antenna element Rx _j is multiplied in order to extract _i .

In 2 × 2 short-range MIMO transmission, the propagation channel phase difference θ _H1 = tan ⁻¹ (h ₂₁ / h ₁₁ ) = − 90 ° and θ _H2 = tan ⁻¹ (h ₁₂ / h ₂₂ ) = In the case of −90 °, that is, when the distance d of the antenna elements is set so that the phase difference of the propagation channel is 90 degrees, the channel capacity is maximized. 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.

Nishimori, Seki, Honma, Hiraga, Mizoguchi, “Study on transmission method suitable for short-range MIMO communication” IEICE Tech. Bulletin, AP2009-83, Sep. 2009. 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-range MIMO transmission, the phase difference θ _H1 = tan ⁻¹ (h ₂₁ / h ₁₁ ) and the phase difference θ _H2 = tan ⁻¹ (h ₁₂ / h ₂₂ ) of the propagation channel are In each case, the channel capacity is maximized when the distance d between the antenna elements is set so that the phase difference is 90 degrees. However, in an actual usage scene, it is assumed that a positional deviation occurs between the transmission array antenna and the reception array antenna.

  FIG. 12 is a diagram illustrating an application example of short-range MIMO transmission. For example, in the example shown in FIG. 12A, when a user downloads content while holding the mobile terminal MT over the information terminal ST, the array antenna STA of the information terminal ST and the array antenna MTA of the mobile terminal MT The space between them becomes a blind spot from the user, and the positional relationship between the array antenna STA of the information terminal ST and the array antenna MTA of the mobile terminal MT cannot be visually confirmed. For this reason, it is difficult to align both antennas so that both array antennas are in an ideal facing state. FIG. 12A shows a case where the mobile terminal MT performs communication in a state where the mobile terminal MT is separated from the information terminal ST by a minute distance, but the touch portion (not shown) of the information terminal ST in which the array antenna STA is installed is used. Even when communication is performed by touching (contacting) the portable terminal MT, the antenna may be displaced for the same reason.

  Further, as shown in FIG. 12B, as another method of antenna alignment, a simple fitting-type connector CN such as a LAN (Local Area Network) connector is provided on the installation base HD of the information terminal ST, For example, the portable terminal MT may be fixedly installed in the connector CN of the installation table HD. According to this method, it is possible to suppress the positional deviation between both antennas within about ± 0.5 mm, but it is difficult to achieve an ideal facing state.

  Also, in the system that performs near-field MIMO transmission with transmitters and receivers facing each other on both sides of a wall between rooms or indoors and outdoors that is presented in Non-Patent Document 2, the walls of the transceiver The positional relationship between the two antennas cannot be confirmed visually. Therefore, in this case as well, it is difficult to align both antennas so that they are in an ideal facing state.

As described above, when the antennas of both the transmitter and the receiver deviate from the optimum positional relationship, the channel matrix H does not become a symmetric matrix, that is, the phase difference θ _H1 and the phase difference θ _{H2 of} the propagation channel are respectively The phase difference is not 90 degrees, and the short-range MIMO transmission characteristics deteriorate.

  The present invention has been made in view of such circumstances, and the purpose of the present invention is to make the positional relationship between the transmitting array antenna and the receiving array antenna for performing short-range MIMO transmission deviate from the desired positional relationship. Provided are a radio communication system and a radio communication method capable of bringing a phase difference of a propagation channel close to a desired value even when the phase difference of the propagation channel is deviated from a desired value (for example, a phase difference of 90 degrees). There is.

  The present invention has been made to solve the above-described problem, 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 reception antenna elements. A radio communication system comprising a receiving array antenna, arranged in a radiation direction of a radio wave radiated from each transmitting antenna element of the transmitting array antenna, and a signal radiated from each transmitting antenna element of the transmitting array antenna A reflection part that reflects in the direction of each receiving antenna element of the receiving array antenna, and a phase difference of a propagation 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 estimation unit to be estimated and the phase difference estimated by the phase difference estimation unit, the inclination of the reflection unit is estimated. And a control unit for controlling either or both of the position, a configuration of a wireless communication system, characterized by comprising.

  In the wireless communication system, for example, the control unit includes a phase rotation amount of a radio wave in a first path from a first transmission antenna element of the transmission array antenna to a first reception antenna element of the reception array antenna, and the A first phase difference that is a difference between a phase rotation amount of a radio wave in a second path from the first transmitting antenna element to the second receiving antenna element of the receiving array antenna; and a second phase of the transmitting array antenna Phase rotation amount of radio wave in the third path from the transmitting antenna element to the first receiving antenna element and phase rotation of radio wave in the fourth path from the second transmitting antenna element to the second receiving antenna element One or both of the inclination and the position of the reflecting portion are controlled based on a second phase difference that is a difference from the quantity.

  In the wireless communication system, for example, when the first phase difference is larger than the second phase difference, the control unit moves in a direction from the first transmission antenna element toward the second transmission antenna element. The reflecting portion is moved.

  In the wireless communication system, for example, the phase difference estimation unit estimates a plurality of phase differences corresponding to the plurality of transmission antenna elements, and the control unit estimates the plurality of phase differences estimated by the phase difference estimation unit. And controlling the tilt or position of the reflector so as to obtain a desired channel capacity by repeatedly performing a process for controlling either or both of the tilt and the position of the reflector. To do.

  In the wireless communication system, for example, the control unit includes a plurality of phase differences with respect to a positional deviation from an optimal positional relationship between the transmission array antenna and the reception array antenna at an arbitrary initial value of the inclination or position of the reflection unit. , Holding a table in which the inclination or position of the reflection unit for approximating the phase difference at which the desired channel capacity can be obtained in the positional deviation amount, and based on the plurality of phase differences estimated by the phase difference estimation unit Then, the tilt or position of the reflecting portion for obtaining a phase difference that obtains a desired channel capacity is obtained from the table, and the reflecting or the reflecting portion is set to the tilt or position obtained from the table. It is characterized by controlling the inclination or position of the part.

  A wireless communication method according to an aspect of the present invention includes a transmission array antenna including a plurality of transmission antenna elements, a reception array antenna including a plurality of reception antenna elements, and radiation from each transmission antenna element of the transmission array antenna. A reflection unit that is arranged in a radiation direction of the radio wave and reflects a signal radiated from each transmission antenna element of the transmission array antenna in a direction of each reception antenna element of the reception array antenna. A wireless communication method comprising: a phase difference estimation procedure for estimating a phase difference of a propagation channel formed between each transmitting antenna element of the transmitting array antenna and each receiving antenna element of the receiving array antenna; and the phase difference Based on the phase difference estimated by the estimation procedure, either or both of the inclination and the position of the reflecting portion. Having a configuration of a wireless communication method characterized by comprising: a control step of controlling the.

  In the wireless communication method, for example, in the control procedure, the phase rotation amount of the radio wave in the first path from the first transmission antenna element of the transmission array antenna to the first reception antenna element of the reception array antenna A first phase difference that is a difference between a phase rotation amount of a radio wave in a second path from the first transmitting antenna element to the second receiving antenna element of the receiving array antenna; and a second phase of the transmitting array antenna Phase rotation amount of radio wave in the third path from the transmitting antenna element to the first receiving antenna element and phase rotation of radio wave in the fourth path from the second transmitting antenna element to the second receiving antenna element One or both of the inclination and the position of the reflecting portion is controlled based on a second phase difference that is a difference from the quantity.

  In the wireless communication method, for example, in the control procedure, when the first phase difference is larger than the second phase difference, the first transmission antenna element is directed to the second transmission antenna element. The reflecting portion is moved.

  In the wireless communication method, for example, in the phase difference estimation procedure, phase differences corresponding to the plurality of transmission antenna elements are estimated, and in the control procedure, based on the plurality of phase differences estimated by the phase difference estimation unit. The tilt or position of the reflector is controlled so that a desired channel capacity can be obtained by repeatedly performing either or both of the processes for controlling the tilt and position of the reflector.

  In the wireless communication method, for example, in the control procedure, a plurality of phase differences with respect to a positional deviation from an optimal positional relationship between the transmitting array antenna and the receiving array antenna at an arbitrary initial value of the inclination or the position of the reflecting unit; Based on the phase difference estimated in the phase difference estimation procedure from the table in which the inclination or position of the reflecting unit for approximating the phase difference at which the desired channel capacity is obtained in the positional deviation amount is associated, Acquire the tilt or position of the reflecting part to approximate the phase difference from which the capacitance is obtained, and control the tilt or position of the reflecting part so that the tilt or position of the reflecting part becomes the tilt or position acquired from the table It is characterized by doing.

  According to the present invention, even when the positions of the transmission array antenna and the reception array antenna deviate from the optimum positional relationship, the phase difference of the propagation channel between the transmission array antenna and the reception array antenna is changed to a desired phase difference. You can get closer. 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 schematic structure of the radio | wireless communications system in the 1st Embodiment of this invention. It is explanatory drawing which shows the relationship between the inclination of a reflection part in 1st Embodiment of this invention, and a phase difference, (A) shows an example of the correspondence of the inclination of a reflection part, and a phase difference, (B) It is a figure which shows the relationship between a transmission array antenna, a reflection part, a propagation channel, and a receiving array antenna. It is explanatory drawing which shows the phase difference adjustment effect in the 1st Embodiment of this invention. It is a flowchart which shows the phase difference adjustment procedure in the 1st Embodiment of this invention. It is an antenna block diagram in the case of 4 branches of the 1st Embodiment of this invention. It is explanatory drawing which shows the phase difference adjustment effect in the 2nd Embodiment of this invention, (A) shows an example of the correspondence of the position shift of a receiving array antenna, and a phase difference, (B) is a transmitting array antenna. It is a figure which shows the relationship between a reflection part, a propagation channel, and a receiving array antenna. It is a flowchart which shows the phase difference adjustment procedure in the 2nd Embodiment of this invention. It is a block diagram which shows schematic structure of the radio | wireless communications system in the 3rd Embodiment of this invention. It is a flowchart which shows the phase difference adjustment procedure in the 3rd 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. It is a figure which shows the example of application of near field MIMO transmission.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<First Embodiment>
FIG. 1 is a configuration diagram showing a schematic configuration of a wireless communication system 1 according to the first embodiment of the present invention. The wireless communication system 1 is a wireless communication system including a transmission array antenna 120 composed of a plurality of transmission antenna elements and a reception array antenna 210 composed of a plurality of reception antenna elements, and is 2 × 2 MIMO (2 Two-sequence (data sequence S1 and data sequence S2) data communication from the information terminal ST to the portable terminal MT is performed by (input 2-output MIMO) transmission. The wireless communication system 1 includes an information terminal 100 and a mobile terminal 200.

The information terminal 100 includes transmission units 111 and 112, a transmission array antenna 120 including a plurality of transmission antenna elements Tx ₁ and Tx ₂ , a radio wave absorber 130, a plurality of reflection units 141, a control unit 150, and an actuator 161. 162. The mobile terminal 200 includes a reception array antenna 210 including a plurality of reception antenna elements Rx ₁ and Rx ₂ , a weight calculation unit 220, reception units 231 and 232, and a phase difference estimation unit 240.

Transmitting unit 111 acquires a data series S1, performs coding processing and modulation, etc., to generate a transmission signal of the data sequence S1, and outputs the generated transmission signal to the transmitting antenna element Tx _1. The transmission unit 112 acquires a data series S2, performs the processing of coding and modulation, etc., to generate a transmission signal of the data sequence S2, and outputs the generated transmission signal to the transmitting antenna element Tx _2. Here, the data series S1 and the data series S2 may be independent data series or may be correlated data series.

The transmission antenna element Tx ₁ is an element for wirelessly transmitting the transmission signal output from the transmission unit 111. The transmission antenna element Tx ₂ is an element for the transmission signals outputted from the transmitting unit 112 wirelessly transmits. The transmission antenna element Tx ₁ and the transmission antenna element Tx ₂ have antenna directivities perpendicular to and opposite to the front direction of the information terminal 100 shown in FIG. 1 (the direction in which the position of the mobile terminal 200 is assumed). It is arranged to face.

Specifically, the transmitting antenna element Tx ₁ is arranged so that the radiation direction of the radio wave faces in a direction orthogonal to the front direction. The transmission antenna element Tx ₂ is a direction in which the radiating direction of the radio wave is perpendicular to the front direction, it is arranged so as to face in the opposite direction to the radial direction of the transmitting antenna element Tx _1. That is, the transmitting antenna element Tx ₁ and the transmitting antenna element Tx ₂ are arranged so that the antenna directivity is set in the direction orthogonal to the front direction and in the opposite directions.

In FIG. 1, for ease of understanding, the transmitting antenna element Tx ₁ and the transmitting antenna element Tx ₂ are schematically shown. However, the transmitting antenna elements Tx ₁ and Tx ₂ are each, for example, a microstrip antenna. It is composed of an antenna with a small thickness. Further, the transmission antenna element Tx ₁ and the transmission antenna element Tx ₂ are arranged at substantially the same position so that the radiating points of the mutual transmission signals are substantially the same. In the following, for convenience of explanation, it is assumed there is no deviation of the position of mutual transmit antenna elements Tx _1, Tx _2, also, the radiation point of the signal by the transmitting antenna elements Tx ₁ and transmitting antenna element Tx ₂ is consistent It is assumed that the origin (0, 0) of the xy coordinates shown in FIG.

Here, the x-axis direction of the xy coordinate system shown in FIG. 1 indicates the front direction of the information terminal 100 (the propagation direction of radio waves from the information terminal 100 to the mobile terminal 200), and the y-axis direction is orthogonal to the x-axis direction. The direction to do. However, as long as the effects of the present invention can be obtained, the radiation points of the transmitting antenna elements Tx ₁ and Tx ₂ may not exactly coincide with each other and may be separated from each other.

The reflection units 141 and 142 are elements for reflecting signals radiated from the transmission antenna elements Tx ₁ and Tx ₂ of the transmission array antenna 120 in the direction of the reception antenna elements Rx ₁ and Rx ₂ of the reception array antenna 210. is there. The reflectors 141 and 142 can be made of any member as long as it has the property of reflecting radio waves. In the first embodiment, the reflectors 141 and 142 are plate-like members, but the limitation is that the signal transmitted from the transmission array antenna 120 can be reflected toward the reception array antenna 210. The shapes of the reflecting portions 141 and 142 can be arbitrarily set.

Reflectors 141 and 142 are arranged in the radiation direction of the radio wave radiated from each transmission antenna element of transmission array antenna 120. Specifically, the reflecting unit 141 is arranged in the radial direction of the radio wave radiated from the transmitting antenna element Tx _1. The reflection surface of the reflection unit 141 forms an angle φ ₁ (hereinafter referred to as an inclination φ ₁ ) with respect to the front direction of the information terminal 100, and the center position of the reflection unit 141 is from the radiation point of the transmission antenna element Tx _1. front direction of the transmitting antenna element Tx ₁ are arranged in spaced (radiation direction of radio wave) a distance d / 2 position. That is, the coordinates (x, y) of the center position of the reflecting portion 141 are set to (0, d / 2). In the first embodiment, the inclination phi ₁ of the reflective part 141 refers to the angle of counterclockwise positive direction with reference of the x-axis, the inclination phi ₂ of the reflecting section 142, clock as a reference in the positive direction of the x-axis The angle around.

The reflection portion 142 is disposed in the radial direction of the radio wave radiated from the transmitting antenna element Tx _2. The reflection surface of the reflection unit 142 forms an angle φ ₂ (hereinafter referred to as an inclination φ ₂ ) with respect to the front direction of the information terminal 100, and the center position of the reflection unit 142 is from the radiation point of the transmission antenna element Tx _2. The transmitting antenna element Tx2 is disposed at a position separated by a distance d / _{2 in} the front direction (radiation direction of radio waves). That is, the coordinates (x, y) of the center position of the reflecting portion 142 are set to (0, −d / 2). Therefore, the center position of the reflecting portion 141 and the center position of the reflecting portion 142 are separated by a distance d.

The control unit 150 is an element for controlling one or both of the inclination and the position of the reflection units 141 and 142 based on the phase difference estimated by the phase difference estimation unit 240 described later. In the first embodiment, the control unit 150 controls only the inclination of the reflection units 141 and 142. The control unit 150 includes a propagation channel phase difference θ _H1 = tan ⁻¹ (h ₂₁ / h ₁₁ ) and a phase difference θ _H2 = tan ⁻¹ (h ₁₂ / h) between the transmission array antenna 120 and the reception array antenna 210. based on the information of _22), by driving the actuators 161 and 162 mechanically controls the inclination phi ₂ of inclination phi ₁ and the reflecting portion 142 of the reflecting section 141.

Here, the phase difference θ _H1 is determined from the phase rotation amount of the radio wave in the path (h ₁₁ ) from the transmission antenna element Tx ₁ of the transmission array antenna 120 to the reception antenna element Rx ₁ of the reception array antenna 210 and the transmission antenna element Tx _1. 6 is a table showing a difference from a phase rotation amount of a radio wave in a path (h ₂₁ ) of the receiving array antenna 210 to the receiving antenna element Rx ₂ . Further, the phase difference θ _H2 is the amount of radio wave phase rotation in the path (h ₁₂ ) from the transmission antenna element Tx ₂ to the reception antenna element Rx ₁ of the transmission array antenna 120 and the transmission antenna element Tx ₂ to the reception antenna element Rx ₂ . Is the difference from the amount of phase rotation of the radio wave in the path (h ₂₂ ).

More specifically, the information terminal 100 transmits a training signal for estimating the phase difference of the propagation channel before transmitting the data sequence S1 and the data sequence S2. Control unit 150, based on the information of the phase difference theta _H1 and the phase difference theta _H2 fed back from the phase difference estimation unit 240 described later of the mobile terminal 200 receives the training signal, a phase difference theta _H1 and the phase difference theta _H2 There by driving the actuator 161, 162 to be closer to the phase difference of 90 degrees, respectively, to mechanically control the inclination phi ₂ of inclination phi ₁ and the reflecting portion 142 of the reflecting section 141.

Thus, in the first embodiment, the control unit 150, based on the phase difference theta _H1 indicated by the information fed back from the mobile terminal 200 and the phase difference theta _H2, reflecting the inclination phi ₁ of the reflecting portion 141 It controls the inclination phi ₂ parts 142.
Note that means for feeding back the phase difference information (θ _H1 , θ _H2 ) estimated by the phase difference estimation unit 240 of the portable terminal 200 to the control of the information terminal 100 is TDD (time division duplex) or FDD (frequency division duplex). ) Etc., and any means can be used, and is not limited to a specific means.

The radio wave absorber 130 is disposed inside the information terminal 100 so as to be positioned between the transmission array antenna 120 and the reception array antenna 210. The radio wave absorber 130 is for suppressing a signal that goes directly from the transmission array antenna 120 to the reception array antenna 210. That is, the radio wave absorber 130 attenuates the power of the signal radiated from the transmission antenna element Tx ₁ and the transmission antenna element Tx ₂ and directly arriving at the reception antenna element Rx ₁ and the reception antenna element Rx ₂ to a negligible level. .

Actually, even if the radio wave absorber 130 is provided, there is no signal that goes directly from the transmission array antenna 120 to the reception array antenna 210. However, in the following description, the transmission array antenna 120 directly connects to the reception array antenna 210. signals directed to specific is negligible, the receive antenna elements Rx ₁ receive antenna element Rx ₂ shall only signals reflected by the reflecting portion 141 and the reflecting portion 142 arrives.

Note that any member can be used in place of the radio wave absorber 130 as long as the power of signals arriving in series from the transmitting array antenna 120 to the receiving array antenna 210 can be suppressed to a negligible level.
Further, the half widths of the directivities of the transmitting antenna elements Tx ₁ and Tx ₂ are narrow, the direct wave from the transmitting antenna element Tx ₁ to the receiving antenna element Rx ₁ and the direct wave from the transmitting antenna element Tx ₂ to the receiving antenna element Rx ₂ . When the wave power is sufficiently small, the wave absorber 130 or the like may be omitted.

The mobile terminal 200 is an element for extracting each series of data from a signal transmitted from the information terminal 100. In the portable terminal 200, each of the receiving antenna elements Rx ₁ and the receiving antenna element Rx _2, a radio signal transmitted from the transmitting antenna element Tx _1, a radio signal transmitted from the transmitting antenna element Tx _2, the two radio signals Is received as a synthesized radio signal. Radio signals received by the receiving antenna element Rx ₁ and the receiving antenna element Rx ₂ are input to the weight calculation unit 220.

Here, the receiving antenna element Rx ₁ and the receiving antenna element Rx ₂ are arranged at positions spaced apart from each other by a distance d in the y-axis direction of the xy coordinate system of FIG. 1, and the receiving antenna element Rx ₁ and the receiving antenna The distance d between the element Rx ₂ is the same as the distance d between the reflection part 141 and the reflection part 142. Further, the receiving antenna element Rx ₁ and the receiving antenna element Rx ₂ are arranged at a position away from the radiation points of the antennas Tx ₁ and Tx ₂ of the transmitting array antenna 120 by a distance D in the x-axis direction of the xy coordinate system of FIG. ing.

When the receiving antenna element Rx ₁ is arranged at the coordinates (D, d / 2) and the receiving antenna element Rx ₂ is arranged at the position of the coordinates (D, -d / 2), the transmission antenna array 120 Assume that the receiving array antenna 210 is in an optimal positional relationship and the channel capacity is maximized. With reference to such an optimal positional relationship, the positional deviation distance of the receiving array antenna 210 in the y-axis direction is represented by Δy.

The weight calculation unit 220 is an element for performing signal separation by multiplying a signal received by the receiving antenna element Rx ₁ and a signal received by the receiving antenna element Rx ₂ by a receiving weight by digital signal processing or an analog circuit. It is. Weight computation unit 220, among the signals obtained by the signal separation of the outputs a signal of the data sequence S1 'of transmit antenna elements Tx ₁ corresponds to the signal sequence S1 for transmitting to the receiving unit 231. The wait operation unit 220, among the signals obtained by the signal separation of the outputs a signal of the data sequence S2 'that transmit antenna elements Tx ₂ corresponding to the signal of the data sequence S2 for transmitting to the receiving unit 232.

  The receiving unit 231 performs processing such as demodulation and decoding on the signal of the data sequence S1 'output from the weight calculation unit 220, and restores and outputs the data sequence S1. In addition, the reception unit 232 performs processing such as demodulation and decoding on the signal of the data sequence S2 'output from the weight calculation unit 220, and restores and outputs the data sequence S2.

The phase difference estimation unit 240 of the mobile terminal 200 calculates the phase difference θ _H1 and phase difference θ _H2 of the propagation channel formed between each transmission antenna element of the transmission array antenna 120 and each reception antenna element of the reception array antenna 210. This is an element for estimation. The phase difference estimation unit 240 feeds back the phase difference information estimated using the training signal transmitted from the information terminal 100 to the control unit 150 of the information terminal 100.

Next, with reference to the evaluation results by simulation shown in FIG. 2 and FIG. 3, the effectiveness regarding the control of the phase difference of the propagation channel by the wireless communication system 1 of the present invention will be described.
FIG. 2 is a diagram for explaining the relationship between the inclinations φ ₁ and φ ₂ of the reflectors 141 and 142 and the phase differences θ _H1 and θ _H2 in the first embodiment of the present invention. 2A shows an example of a correspondence relationship between the inclinations φ ₁ and φ ₂ of the reflecting portions 141 and 142 and the phase differences θ _H1 and θ _H2 , and FIG. 2B shows the relationship between the transmission array antenna 120 and FIG. it is a diagram showing a relationship between the reflective portion 141 and 142 elements _h 11 of the channel matrix of the propagation _channel, and _{h 21,} h 12, h ₂₂ and the receiving array antenna 210.

In FIG. 2 (A), the abscissa x represents the inclination phi ₂ of inclination phi ₁ and the reflecting portion 142 of the reflecting section 141, the vertical axis y represents a phase difference theta _H1 and the phase difference theta _H2 propagation channel. The xy coordinate system in FIG. 2 matches the xy coordinate system in FIG. In the example of FIG. 2A, the frequency of the signal transmitted from the transmission array antenna 120 is set to 60.48 GHz, and the transmission / reception interval D between the transmission array antenna 120 and the reception array antenna 210 is set to 20 mm. The distance d between the reflecting portion 141 and the reflecting portion 142, that is, the element spacing d of the receiving array antenna 210 is set to 7.2 mm, and the positional deviation Δy of the receiving array antenna 210 is set to 1 mm.

As understood from FIG. 2 (A), the by increasing the inclination phi ₂ of inclination phi ₁ and the reflecting portion 142 of the reflecting section 141, respectively, a phase difference theta _H1 and the absolute value of the phase difference theta _H2 propagation channel Can be reduced. Further, by decreasing the inclination phi ₂ of inclination phi ₁ and the reflecting portion 142 of the reflecting section 141, respectively, it is possible to increase the absolute value of the phase difference theta _H1 and the phase difference theta _H2 propagation channel.

FIG. 3 is a diagram showing the effect of phase difference adjustment in the first embodiment of the present invention.
3, the horizontal axis indicates the positional deviation Δy (mm) of the receiving array antenna 210 in the y-axis direction of the xy coordinate system shown in FIG. 1 or FIG. 2, and the left vertical axis indicates the phase differences θ _H1 and θ _H2 . The right vertical axis indicates the inclination of the reflecting portion. In the example of FIG. 3, the frequency of the signal transmitted from the transmission array antenna 120 is set to 60.48 GHz, the transmission / reception interval D between the transmission array antenna 120 and the reception array antenna 210 is set to 20 mm, and the reflection unit The distance d between 141 and the reflector 142, that is, the element distance d of the receiving array antenna 210 is set to 7.2 mm. For comparison, FIG. 3 also shows the characteristics of the phase difference with respect to the positional deviation in the case of normal 2 × 2 MIMO transmission that does not use the reflection unit 141. The element interval d of the transmission array antenna 120 is determined by the reception array antenna 210. It is set to 7.2 mm similarly to the above.

As can be seen from FIG. 3, when the reflectors 141 and 142 are not used, the phase difference θ _H1 and the phase difference θ _{H2 of} the propagation channel are each 90 degrees as the positional deviation Δy of the receiving array antenna 210 increases. It shows a tendency to deviate from the phase difference. In contrast, when using a reflective portion 141 and 142, controls the inclination phi ₂ of inclination phi ₁ and the reflecting portion 142 of the reflecting section 141, the values shown on the right vertical axis of Figure 3 corresponding to the displacement Δy As a result, the phase difference θ _H1 and the phase difference θ _H2 of the propagation channel can each be close to a phase difference of 90 degrees. Therefore, the channel capacity can be improved.

Next, a flowchart of phase difference adjustment in the present embodiment will be described with reference to FIG.
First, when the user holds or installs portable terminal 200 over information terminal 100 (step ST1), information terminal 100 transmits a training signal before transmitting signals of data series S1 and data series S2 (step ST2). . The mobile terminal 200 receives the training signal, and the phase difference estimation unit 240 estimates a plurality of phase differences of the propagation channels corresponding to the plurality of transmission antenna elements Tx ₁ and Tx ₂ . Then, after estimating the plurality of phase differences of the propagation channel, the phase difference estimation unit 240 feeds back information on the phase difference to the control unit 150 of the information terminal 100 (step ST3).

Based on the plurality of phase differences estimated by the phase difference estimation unit 240, the control unit 150 repeatedly performs the process of controlling the inclinations φ ₁ and φ ₂ of the reflection units 141 and 142, thereby obtaining a desired channel capacity. Thus, the inclinations φ ₁ and φ ₂ of the reflecting portions 141 and 142 are controlled. Specifically, if the numerical value of the phase difference fed back from the phase difference estimation unit 240 of the mobile terminal 200 is within a predetermined range based on the 90 degree phase difference (step ST4: YES), the information terminal 100 The control unit 150 finishes adjusting the inclinations of the reflecting units 141 and 142 (step ST7), and the information terminal 100 starts transmission of signals of the data series S1 and the data series S2. If the value of the phase difference fed back does not fall within a predetermined range based on the 90 ° phase difference (step ST4: NO), the control unit 150 causes the actuator 161, the actuator 161, to approach the phase difference of 90 °. By driving 162, each inclination of the reflection parts 141 and 142 is mechanically controlled, and it is determined whether each inclination of the reflection parts 141 and 142 has reached the upper limit of the movable range (step ST5).

  If the inclinations of the reflecting parts 141 and 142 do not reach the upper limit of the movable range (step ST5: NO), the inclinations of the reflecting parts 141 and 142 are set so that the phase difference approaches 90 degrees. Control is repeated (step ST6). Then, when the deviation from the 90-degree phase difference falls within a predetermined range in the process of the above repeating process (step ST5: YES), the control unit 150 ends the adjustment of each inclination of the reflecting units 141 and 142. Then (step ST7), the information terminal 100 starts signal transmission.

The present invention is not limited to the 2 × 2 MIMO transmission described above, and can be extended to 4 × 4 MIMO transmission.
FIG. 5 shows an antenna configuration on the information terminal 100 side in the case of 4 × 4 MIMO transmission. The transmitting antenna element Tx ₁ , the transmitting antenna element Tx ₂ , the transmitting antenna element Tx _3, and the transmitting antenna element Tx ₄ are arranged so that the antenna directivity is directed in the direction perpendicular to the front direction of the information terminal and opposite to each other. Yes. Reflecting unit 141, an angle phi ₁ with respect to the front direction of the information terminal 100, the center of the reflecting section 141 is spaced apart by a distance d / 2 in the front direction of the transmitting antenna element Tx _1. The reflection unit 142, an angle phi ₂ with respect to the front direction of the information terminal 100, the center of the reflecting section 142 is spaced apart by a distance d / 2 in the front direction of the transmitting antenna element Tx _2. The reflection unit 143, an angle phi ₃ with respect to the front direction of the information terminal 100, the center of the reflecting section 143 is spaced apart by a distance d / 2 in the front direction of the transmitting antenna element Tx _3. Moreover, the reflection part 144 makes an angle φ ₄ with respect to the front direction of the information terminal 100, and the center of the reflection part 144 is arranged at a distance d / 2 in the front direction of the transmission antenna element Tx ₄ .

Actuators 161 to 164 controlled by the control unit 150 are connected to the reflection units 141 to 144, respectively, and each actuator can change the inclination of each reflection unit by a control signal from the control unit 150. . The control unit 150 controls the actuators 161 and 162 based on information on the phase difference θ _H1 = tan ⁻¹ (h ₂₁ / h ₁₁ ) and the phase difference θ _H2 = tan ⁻¹ (h ₁₂ / h ₂₂ ) of the propagation channel. driven, mechanically controlled inclination phi ₂ of inclination phi ₁ and the reflecting portion 142 of the reflecting section 141. The control unit 150 also determines the actuator 163 based on the information on the phase difference θ _H3 = tan ⁻¹ (h ₄₃ / h ₃₃ ) and the phase difference θ _H4 = tan ⁻¹ (h ₃₄ / h ₄₄ ) of the propagation channel. 164 drives the mechanically controlled with the inclination phi ₃ of the reflecting portion 143 of the inclination phi ₄ of the reflecting portion 144.

More specifically, the information terminal 100 transmits a training signal for estimating the phase difference of the propagation channel before transmitting the data series S1 to S4, and the phase difference estimation unit 240 of the mobile terminal 200 The phase difference information estimated using the training signal is fed back to the control unit 150 of the information terminal 100. Based on the information on the fed back phase differences θ _H1 , θ _H2 , θ _H3 , θ _H4 , the control unit 150 _converts each of the phase differences θ _H1 , θ _H2 , θ _H3 , θ _H4 to a phase difference of 90 degrees. The actuators 161 to 164 are driven so as to approach each other, and the inclinations φ ₁ , φ ₂ , φ ₃ , and φ ₄ of the reflecting portions 141 to 144 are mechanically controlled. Others are the same as the radio | wireless communications system applied to the above-mentioned 2x2 MIMO transmission.

In the configuration of FIG. 1, only the information terminal 100 includes the reflection units 141 and 142 and controls the inclinations φ ₁ and φ ₂ of the reflection units 141 and 142, but the information terminal 100 and the portable terminal 200 are Each of them may have a reflecting portion, and both may be configured to control the inclination of the reflecting portion.
In addition, a case has been described where the information terminal 100 transmits a training signal to the mobile terminal 200 and the phase difference estimation unit 240 of the mobile terminal 200 estimates the phase difference θ _H1 and the phase difference θ _H2 of the propagation channel from the training signal. The information terminal 100 may include the phase difference estimation unit 240, and the information terminal 100 may estimate the phase difference using the training signal transmitted by the mobile terminal 200.

Further, although the case where the training signal is used to estimate the phase differences θ _H1 and θ _H2 of the propagation channel has been described, the phase difference may be estimated by blind estimation without using the training signal.
Further, in the present embodiment, the phase differences θ _H1 and θ _H2 of the propagation channels are close to a phase difference of 90 degrees, but the present invention is not limited to this, and the channel capacity can be improved. The phase differences θ _H1 and θ _H2 of the propagation channels may be close to arbitrary desired values. The same applies to other embodiments described later.

<Second Embodiment>
In the first embodiment, the case where the inclinations φ ₁ and φ ₂ of the reflecting portions 141 and 142 are controlled has been described. In the second embodiment, the positions of the reflecting portions 141 and 142 are controlled. The apparatus configuration of the second embodiment is the same as that of the first embodiment except that the control unit 150 controls the positions of the reflection units 141 and 142 instead of the inclination of the reflection units 141 and 142.

The information terminal 100 transmits a training signal for estimating the phase differences θ _H1 and θ _H2 of the propagation channels before transmitting the data series S1 and the data series S2, and the phase difference estimation unit 240 of the mobile terminal 200 The phase difference information estimated using the training signal transmitted from the information terminal 100 is fed back to the control unit 150 of the information terminal 100. The control unit 150 determines the position based on the information of the phase difference θ _H1 = tan ⁻¹ (h ₂₁ / h ₁₁ ) and the phase difference θ _H2 = tan ⁻¹ (h ₁₂ / h ₂₂ ) fed back from the mobile terminal 200. Actuators 161 and 162 are driven so that the phase differences θ _H1 and θ _H2 approach the phase difference of 90 degrees, and the positions of the reflecting portions 141 and 142 are mechanically controlled as described below. Thus, the respective deviation amounts of the propagation channel phase differences θ _H1 and θ _H2 from the desired 90-degree phase difference are within a predetermined range in which the desired channel capacity can be obtained.

For example, when the receiving array antenna 210 is shifted in the direction from the receiving antenna element Rx ₂ to the receiving antenna element Rx ₁ as shown in FIG. 2, the path length from the transmitting antenna element Tx ₁ to the receiving antenna element Rx ₁ ; Since the path length difference from the transmitting antenna element Tx ₁ to the receiving antenna element Rx ₂ is small, the absolute value | θ _H1 | of the propagation channel phase difference θ _H1 is also small. On the other hand, since the difference between the path length from the transmitting antenna element Tx ₂ to the receiving antenna element Rx ₁ and the path length from the transmitting antenna element Tx ₂ to the receiving antenna element Rx ₂ becomes large, the absolute difference of the phase difference θ _H2 of the propagation channel The value | θ _H2 | also increases. Therefore, by referring to the value of | θ _H1 | or | θ _H2 |, the direction of positional deviation of the receiving array antenna 210 can be detected.

The control unit 150 moves the center positions of the reflection units 141 and 142 so as to compensate for the detected positional deviation of the reception array antenna 210. Specifically, as illustrated in the example of FIG. 2, the control unit 150 corresponds to the transmission antenna element Tx ₁ having an absolute value | θ _H2 | of the phase difference θ _H2 of the propagation channel corresponding to the transmission antenna element Tx _2. When the phase difference θ _H1 of the propagation channel is larger than the absolute value | θ _H1 |, the direction from the transmitting antenna element Tx ₂ toward the transmitting antenna element Tx ₁ is detected as the position shift direction of the receiving array antenna 210. In this case, the control unit 150 moves the reflecting units 141 and 142 in the direction from the transmission antenna element Tx ₂ toward the transmission antenna element Tx ₁ . The control unit 150 moves the reflection unit 141 and the reflection unit 142 in the same direction as the detected position shift direction of the reception array antenna 210 by, for example, the same distance as the position shift Δymm of the reception array antenna 210 to thereby propagate the propagation channel. Both of the phase differences θ _H1 and θ _H2 are brought close to the phase difference of 90 degrees. However, the present invention is not limited to this example, and the amount of deviation of each of the phase differences θ _H1 and θ _H2 of the propagation channel from the desired phase difference is limited to be within a predetermined range where a desired channel capacity can be obtained. The amount of movement of each of the reflecting part 141 and the reflecting part 142 is arbitrary. In this case, the movement amount of the reflection unit 141 and the movement amount of the reflection unit 142 may be different from each other.

FIG. 6 is a diagram showing the effect of phase difference adjustment in the second embodiment of the present invention. Here, FIG. 6A shows an example of a correspondence relationship between the positional deviation Δy of the reception array antenna 210 and the phase differences θ _H1 and θ _H2 , and FIG. 6B shows the transmission array antenna 120 and the reflectors 141, 142 is a diagram illustrating a relationship between the element h ₁₁ , h ₂₁ , h ₁₂ , h ₂₂ of the channel matrix 142 of the propagation channel and the receiving array antenna 210. In FIG. 6, the horizontal axis indicates the positional deviation Δymm of the receiving array antenna 210, and the left vertical axis indicates the phase difference θ _H1 and the phase difference θ _H2 . FIG. 6 shows the result when the reflecting portions 141 and 142 are moved by the actuators 161 and 162 by the same distance as the positional deviation Δy (mm) of the receiving array antenna 210. In the example of FIG. 6, the frequency of the signal transmitted from the transmission array antenna 120 is set to 60.48 GHz, the transmission / reception interval D between the transmission array antenna 120 and the reception array antenna 210 is set to 20 mm, and reflection is performed. The distance d between the part 141 and the reflecting part 142, that is, the element distance d of the receiving array antenna 210 is set to 7.2 mm, and the inclinations of the reflecting parts 141 and 142 are set to 40 degrees.

For comparison, FIG. 6 also shows the characteristics of the phase difference with respect to the positional deviation in the case of normal 2 × 2 MIMO transmission that does not use the reflection units 141 and 142. The element spacing d of the transmission array antenna 120 is the reception array. Similar to the antenna 210, it is set to 7.2 mm. As can be seen from FIG. 6, when the reflection units 141 and 142 are not used, as the positional deviation Δy of the receiving array antenna 210 increases, the phase difference θ _H1 and the phase difference θ _H2 are respectively determined from the phase difference of 90 degrees. Shows a tendency to shift. On the other hand, when the reflecting portions 141 and 142 are used, by controlling the positions of the reflecting portions 141 and 142, the phase difference θ _H1 and the phase difference θ _H2 can be brought close to a phase difference of 90 degrees, respectively. .

Next, a flowchart of phase difference adjustment in the present embodiment will be described with reference to FIG.
First, when the user holds or installs portable terminal 200 over information terminal 100 (step ST21), information terminal 100 transmits a training signal before transmitting signals of data series S1 and data series S2 (step ST22). ). The mobile terminal 200 receives the training signal, and the phase difference estimation unit 240 estimates a plurality of phase differences θ _H1 and θ _H2 corresponding to the plurality of transmission antenna elements Tx ₁ and Tx ₂ . Then, after estimating the phase difference of the propagation channel, the phase difference estimation unit 240 feeds back the phase difference information to the control unit (step ST23).

The control unit 150 repeatedly obtains a desired channel capacity by repeatedly performing the process of controlling the positions of the reflection units 141 and 142 based on the plurality of phase differences θ _H1 and θ _H2 estimated by the phase difference estimation unit 240. In this way, the positions of the reflecting portions 141 and 142 are controlled. Specifically, the control unit 150 sets the numerical values of the phase differences θ _H1 and θ _H2 fed back from the phase difference estimation unit 240 of the mobile terminal 200 within a predetermined range based on the phase difference of 90 degrees. It is determined whether or not (step ST24). If the values of the fed back phase differences θ _H1 and θ _H2 are within a predetermined range (step ST24: YES), control unit 150 ends the adjustment of the positions of reflecting units 141 and 142 (step ST26). The information terminal 100 starts transmission of signals of the data series S1 and the data series S2.

On the other hand, if the numerical values of the phase differences θ _H1 and θ _H2 fed back from the mobile terminal 200 do not fall within a predetermined range based on the phase difference of 90 degrees (step ST24: NO), the control unit 150 The positions of the reflecting parts 141 and 142 are mechanically controlled by the actuators 161 and 162 so as to approach the phase difference of 90 degrees, and it is determined whether the positions of the reflecting parts 141 and 142 have reached the upper limit of the movable range ( Step ST25). And the control part 150 controls each position of the reflection parts 141 and 142 so that the numerical value of fed back phase difference (theta) _H1 , (theta) _H2 may approach 90 degree phase difference (step ST26).

If the positions of the reflecting portions 141 and 142 do not reach the upper limit of the movable range (step ST25: NO), the control unit 150 causes the phase differences θ _H1 and θ _H2 to approach the 90-degree phase difference. The respective positions of the reflecting portions 141 and 142 are repeatedly controlled (step ST26). When the deviation from the 90-degree phase difference falls within a predetermined range in the process of the above-described repetition processing (step ST25: YES), the control unit 150 ends the adjustment of the positions of the reflecting units 141 and 142. Then (step ST27), the information terminal 100 starts signal transmission.

<Third Embodiment>
Next, a third embodiment of the present invention will be described.
In the first embodiment and the second embodiment described above, the inclination and position of the reflecting portion are gradually changed so that the phase difference of the propagation channel approaches 90 degrees. However, the third embodiment Then, the control value is acquired from the database and brought close to the desired 90 degree phase difference in a single process. This makes it possible to shorten the adjustment time before starting data communication. In the third embodiment, the configuration shown in FIG. 1 of the first embodiment is partially used.

FIG. 8 is a configuration diagram illustrating a schematic configuration of the wireless communication system 3 according to the third embodiment of the present invention. The wireless communication system 3 according to the third embodiment shown in FIG. 8 further includes a setting value DB (DB: database) 170 in the configuration of the wireless communication system 1 according to the first embodiment shown in FIG. The setting value DB 170 stores a positional deviation Δy from the optimal positional relationship between the transmitting array antenna 120 and the receiving array antenna 210 at an arbitrary initial value of the inclination or position of the reflecting portions 141 and 142, and a phase difference θ _H1 in the positional deviation Δy. , Θ _H2 is held in a table (not shown) in which the optimum values of the inclination or the position of the reflecting part for bringing the desired channel capacity close to a desired 90 degree phase difference is obtained.

Based on the estimated phase difference information fed back from the mobile terminal 200, the control unit 150 reflects the phase differences θ _H1 and θ _H2 from the setting value DB 170 to a desired 90-degree phase difference. Get the optimal value of the slope or position of the. Then, the control unit 150 causes the actuators 161 and 162 in the first embodiment shown in FIG. 1 to incline or position the reflecting units 141 and 142 so that the inclinations or positions of the reflecting units 141 and 142 become the optimum values, respectively. To control. Others are the same as those in the first embodiment or the second embodiment.

Next, a flowchart of phase difference adjustment in the present embodiment will be described with reference to FIG.
First, when the user holds or installs portable terminal 200 over information terminal 100 (step ST31), information terminal 100 transmits a training signal before transmitting signals of data series S1 and data series S2 (step ST32). ). The mobile terminal 200 receives the training signal, and after the phase difference estimation unit 240 estimates the phase differences θ _H1 and θ _H2 of the propagation channels, the phase difference information is fed back to the control unit 150 (step ST33). If the numerical values of the phase differences θ _H1 and θ _H2 fed back from the phase difference estimation unit 240 are within a predetermined range based on the phase difference of 90 degrees (step ST34: YES), the control unit 150 reflects the light. The adjustment of the inclinations or positions of the units 141 and 142 is ended (step ST36), and the information terminal 100 starts transmission of signals of the data series S1 and the data series S2.

On the other hand, if the numerical values of the phase differences θ _H1 and θ _H2 fed back from the mobile terminal 200 are not within a predetermined range based on the desired 90-degree phase difference (step ST34: NO), the control unit 150 obtains the optimum value of the inclination or position of the reflecting portions 141 and 142 for making the phase differences θ _H1 and θ _H2 approach the phase difference of 90 degrees from the set value DB 170, and the inclination or position of the reflecting portions 141 and 142. The actuators 161 and 162 are driven so that the inclination or the position of the reflecting portions 141 and 142 is controlled so that becomes an optimum value (step ST35). Thereafter, the information terminal 100 starts signal transmission.
In the third embodiment, the case where only one of the inclination and the position of the reflecting portions 141 and 142 is controlled has been described. However, the present invention is not limited to this example, and both the inclination and the position of the reflecting portions 141 and 142 are controlled. May be controlled.

In each of the above-described embodiments, the present invention is expressed as a wireless communication system, but the present invention can also be expressed as a wireless communication method. In this case, the wireless communication method according to the present invention radiates from a transmission array antenna configured from a plurality of transmission antenna elements, a reception array antenna configured from a plurality of reception antenna elements, and each transmission antenna element of the transmission array antenna. A reflection unit that is arranged in a radiation direction of the radio wave and reflects a signal radiated from each transmission antenna element of the transmission array antenna in a direction of each reception antenna element of the reception array antenna. A wireless communication method comprising: a phase difference estimation procedure for estimating a phase difference of a propagation channel formed between each transmitting antenna element of the transmitting array antenna and each receiving antenna element of the receiving array antenna; and the phase difference Based on the phase difference estimated by the estimation procedure, either one of the inclination and the position of the reflection unit or It can be expressed as a wireless communication method characterized by comprising: a control step of controlling the person.
In the wireless communication method corresponding to the wireless communication system according to each embodiment described above, the phase difference estimation procedure corresponds to the operation or processing of the phase difference estimation unit 240 in each embodiment, and the control procedure is the control unit in each embodiment. This corresponds to 150 operations or processes.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and arbitrary modifications and corrections can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1,3 ... Wireless communication system, 100 ... Information terminal, 111, 112 ... Transmission part, 120 ... Transmission array antenna, 130 ... Radio wave absorber, 141, 142 ... Reflection part, 150 ... Control part, 161, 162 ... Actuator, 170 ... setting value DB, 200 ... mobile terminal, 210 ... reception array antenna, 220 ... weight calculation unit, 231, 232 ... reception unit, 240 ... phase difference estimation unit, Tx ₁ , Tx ₂ , Rx ₁ , Rx ₂ ... antenna Element, ST1 to ST7, ST21 to ST27, ST31 to ST36 ... processing steps.

Claims (10)

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,
Wherein disposed from said transmit antenna elements in each transmitting antenna elements of the transmitting array antenna in the radiation direction of the radio waves radiated, reflected signals emitted from the transmitting antenna elements in the direction of the receiving antenna elements of the receiving array antennas A plurality of reflective portions to be
A phase difference estimation unit that estimates a phase difference of a propagation 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, a control unit that controls either or both of the inclination and the position of the reflection unit;
A wireless communication system comprising: The transmitting array antenna is
A first transmitting antenna element and a second transmitting antenna element;
The receiving array antenna is
A first receiving antenna element and a second receiving antenna element;
The controller is
Second from the previous SL first transmit antenna the first the and phase rotation amount of radio waves in the path of the first transmission antenna elements from element Previous Symbol first receive antenna element Previous Stories second receive antenna elements said first phase difference is a difference between the phase rotation amount of radio waves in the path, the pre-Symbol third phase rotation amount of radio waves in the path from the second transmit antenna element to said first receive antenna elements Based on the second phase difference, which is the difference from the phase rotation amount of the radio wave in the fourth path from the second transmitting antenna element to the second receiving antenna element, one of the inclination and the position of the reflecting portion. One or both are controlled. The wireless communication system according to claim 1, wherein one or both are controlled. The controller is
The said reflection part is moved to the direction which goes to the said 2nd transmission antenna element from the said 1st transmission antenna element, when the said 1st phase difference is larger than the said 2nd phase difference. The wireless communication system according to 2. The phase difference estimator is
Estimating a plurality of phase differences corresponding to the plurality of transmitting antenna elements;
The controller is
Based on the plurality of phase differences estimated by the phase difference estimation unit, by repeatedly performing a process of controlling either or both of the inclination and the position of the reflection unit, the desired channel capacity can be obtained. The wireless communication system according to any one of claims 1 to 3, wherein an inclination or a position of the reflection unit is controlled. The controller is
A desired channel capacity can be obtained in a plurality of phase differences with respect to a positional deviation from an optimum positional relationship between the transmitting array antenna and the receiving array antenna at an arbitrary initial value of the inclination or position of the reflecting section and the positional deviation amount. It holds a table in which the inclination or position of the reflecting portion is associated to approximate the phase difference, on the basis of the phase difference of the plurality of phase difference estimation unit has estimated the desired channel capacity from the table is obtained An inclination or position of the reflecting part for approaching a phase difference is acquired, and the inclination or position of the reflecting part is controlled so that the inclination or position of the reflecting part becomes the inclination or position acquired from the table. The wireless communication system according to any one of claims 1 to 3. A transmission array antenna composed of a plurality of transmission antenna elements;
A receiving array antenna composed of a plurality of receiving antenna elements;
Wherein disposed from said transmit antenna elements in each transmitting antenna elements of the transmitting array antenna in the radiation direction of the radio waves radiated, reflected signals emitted from the transmitting antenna elements in the direction of the receiving antenna elements of the receiving array antennas A plurality of reflective portions to be
A wireless communication method by a wireless communication system comprising:
A phase difference estimation procedure for estimating a phase difference of a propagation 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 procedure, a control procedure for controlling either or both of the inclination and the position of the reflection unit;
A wireless communication method comprising: The transmitting array antenna is
A first transmitting antenna element and a second transmitting antenna element;
The receiving array antenna is
A first receiving antenna element and a second receiving antenna element;
In the control procedure,
Second from the previous SL first transmit antenna the first the and phase rotation amount of radio waves in the path of the first transmission antenna elements from element Previous Symbol first receive antenna element Previous Stories second receive antenna elements said first phase difference is a difference between the phase rotation amount of radio waves in the path, the pre-Symbol third phase rotation amount of radio waves in the path from the second transmit antenna element to said first receive antenna elements Based on the second phase difference, which is the difference from the phase rotation amount of the radio wave in the fourth path from the second transmitting antenna element to the second receiving antenna element, one of the inclination and the position of the reflecting portion. One or both are controlled. The wireless communication method according to claim 6. In the control procedure,
The said reflection part is moved to the direction which goes to the said 2nd transmission antenna element from the said 1st transmission antenna element, when the said 1st phase difference is larger than the said 2nd phase difference. 8. The wireless communication method according to 7. In the phase difference estimation procedure,
Estimating a phase difference corresponding to the plurality of transmitting antenna elements;
In the control procedure,
Based on the plurality of phase differences estimated in the phase difference estimation procedure, by repeatedly performing a process for controlling either or both of the inclination and the position of the reflection unit, the desired channel capacity can be obtained. The wireless communication method according to any one of claims 6 to 8, wherein the inclination or the position of the reflection unit is controlled. In the control procedure,
A desired channel capacity can be obtained in a plurality of phase differences with respect to a positional deviation from an optimum positional relationship between the transmitting array antenna and the receiving array antenna at an arbitrary initial value of the inclination or position of the reflecting section and the positional deviation amount. Based on the plurality of phase differences estimated in the phase difference estimation procedure from the table in which the inclination or position of the reflecting unit for approaching the phase difference is associated, the phase difference for obtaining a desired channel capacity is obtained. The inclination or position of the reflection part is acquired, and the inclination or position of the reflection part is controlled so that the inclination or position of the reflection part becomes the inclination or position acquired from the table. The wireless communication method according to claim 8.

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