JP6513590B2 - Wireless communication system and communication method of wireless communication system - Google Patents

Description

  The present invention relates to a wireless communication system and a communication method of the wireless communication system.

  In wireless communication systems, techniques have been proposed to increase transmission capacity by multiplexing electromagnetic waves using orbital angular momentum (OAM: Orbital Angular Momentum) (for example, Non-Patent Documents 1 and 2). That is, when the phase distributions of the electromagnetic waves having different OAM modes are orthogonal to each other, the electromagnetic waves of each OAM mode can be separated by the processing of the receiving station. Thus, electromagnetic waves can be multiplexed and transmitted using the OAM.

O. Edfors and A. J. Johansson, “Is orbital angular moment (OAM) based radio communication an unexploited area?”, IEEE transactions on antenna and propagation, Vol. 60, No. 2, pp. 1126-1131, 2012 M. Tamagnone, JS Santiago, S. Capdevila, JR Mosig, J. Perruisseau-Carrier, "The orbital angular momentum (OAM) multiplexing controversy: OAM as a subset of MIMO", IEEE 9th Conference on Antennas and Propagation, pp. 1 -5, 2015

  The electromagnetic wave of OAM propagates in space while maintaining the spiral phase distribution. In addition, the energy of the OAM electromagnetic wave is spatially diffused.

  For this reason, in order to receive OAM electromagnetic waves with a predetermined reception power, it is necessary to increase the aperture diameter of the antenna according to the propagation distance, and the scale of the wireless communication system increases as the propagation distance increases. .

  An object of the present invention is to provide a wireless communication system and a communication method of the wireless communication system which can receive an electromagnetic wave of OAM with high accuracy as compared with the prior art without increasing the aperture diameter of the antenna.

A first invention is a wireless communication system including a transmitting station, a receiving station, and a beam control element, wherein the transmitting station modulates an electromagnetic wave based on a signal including data to be transmitted, and a modulator the transmission circular array antenna having a plurality of transmit antenna elements for radiating modulated electromagnetic waves and a transmitting antenna unit including a plurality of sets in the beam control element inputs the electromagnetic wave radiated from the transmit antenna section, is input comprising electromagnetic wave lens unit for outputting the changed radial, the receiving station includes a receiving antenna unit including a plurality of sets of receive circular array antenna having a plurality of receive antenna elements for receiving an output electromagnetic wave from the lens unit, and a demodulator for receiving the antenna unit demodulates the received signal of the electromagnetic wave received, the transmitting antenna unit is disposed on a vertical two-dimensional plane with respect to the optical axis of the lens portion , And the receiving antenna unit has a plurality of receiving circular array antennas disposed on a two-dimensional plane perpendicular to the optical axis direction of the lens unit, and the transmitting station A signal generation unit that generates a reference signal that causes each of the transmission circular array antennas to emit an electromagnetic wave; and a control unit that causes each of the transmission circular array antennas to emit an electromagnetic wave of the reference signal. The measurement unit includes a measurement unit that measures the reception state of an electromagnetic wave of the received reference signal for each transmission circular array antenna and outputs the measurement result to the transmission station, and the control unit determines the signal including data based on the measurement result. the transmission circular array antenna for radiating electromagnetic waves, select from a plurality of sets of transmitting circular array antenna.

In the first invention, the lens unit may send electromagnetic image of the radiated from Shinen shaped array antenna, at a position where the receiving antenna unit is arranged so as to form an image with the size of the receiving Shinen shaped array antenna , Disposed between the transmitting antenna unit and the receiving antenna unit.

In the first invention, the transmitting antenna unit has a plurality of sets of transmitting circular array antennas arranged concentrically on a two-dimensional plane perpendicular to the optical axis direction of the lens unit, and the receiving antenna unit is on the vertical two-dimensional plane with respect to the optical axis of the lens portion has a plurality of sets of received circular antenna arrays arranged concentrically, the lens unit, the radiation from each of multiple sets of transmitting circular array antenna electromagnetic image of being found at a position where the receiving antenna unit is arranged so as to form an image in one of the magnitude of the multiple sets of received circular array antenna, disposed between the receiving antenna unit and the transmitting antenna unit Be done.

In the first invention, the transmitting station includes an OAM mode selector which selects an Orbital Angular Momentum (OAM) mode to be modulated in the modulator based on information added to a signal including data, The unit modulates an electromagnetic wave having the OAM mode selected by the OAM mode selection unit based on a signal including data, and the transmission antenna unit emits an electromagnetic wave having the OAM mode modulated by the modulation unit.

A second invention is a communication method of a wireless communication system including a transmitting station, a receiving station, and a beam control element, wherein the transmitting station modulates an electromagnetic wave based on a signal including data to be transmitted. A self- element includes a first transmission step in which a transmitting station radiates a modulated electromagnetic wave using a transmission antenna unit including a plurality of transmission circular array antennas having a plurality of transmission antenna elements, and a beam control element An imaging step in which an electromagnetic wave radiated from a transmitting antenna unit is input using a lens unit, and the radiation direction of the input electromagnetic wave is changed and output, and a receiving circular array in which a receiving station has a plurality of receiving antenna elements using the reception antenna unit including a plurality of sets of antennas, a first reception step of receiving the output electromagnetic wave from the lens unit, the receiving station, the electromagnetic reception antenna unit receives And a demodulation step of demodulating the received signal, the transmitting antenna unit includes a plurality of sets of transmitting circular antenna arrays disposed on a vertical two-dimensional plane with respect to the optical axis of the lens unit, the receiving antenna unit Has a plurality of sets of receiving circular array antennas arranged on a two-dimensional plane perpendicular to the optical axis direction of the lens unit, and the transmitting station radiates an electromagnetic wave of a reference signal to each of the transmitting circular array antennas A second transmitting step of causing the receiving station to receive an electromagnetic wave of a reference signal radiated by each of the transmitting circular array antennas using the receiving antenna unit; and a receiving station receiving the electromagnetic wave by the receiving antenna unit Measuring the reception state of the electromagnetic waves of the reference signal for each transmitting circular array antenna and outputting the measurement result to the transmitting station, and the measurement result received by the transmitting station from the receiving station Based on the transmission circular array antenna for radiating electromagnetic waves of a signal including data, Ru further a selection step of selecting from a plurality of sets of transmitting circular array antenna.

In the second invention, the lens unit may send electromagnetic image of the radiated from Shinen shaped array antenna, at a position where the receiving antenna unit is arranged so as to form an image with the size of the receiving Shinen shaped array antenna , Disposed between the transmitting antenna unit and the receiving antenna unit.

In the second invention, the transmitting antenna unit has a plurality of sets of transmitting circular array antennas arranged concentrically on a two-dimensional plane perpendicular to the optical axis direction of the lens unit, and the receiving antenna unit is on the vertical two-dimensional plane with respect to the optical axis of the lens portion has a plurality of sets of received circular antenna arrays arranged concentrically, the lens unit, the radiation from each of multiple sets of transmitting circular array antenna electromagnetic image of being found at a position where the receiving antenna unit is arranged so as to form an image in one of the magnitude of the multiple sets of received circular array antenna, disposed between the receiving antenna unit and the transmitting antenna unit Be done.

In the second invention, the transmitting station, based on information added to the signal containing the data, orbital angular momentum for modulating (OAM: Orbital Angular Momentum) comprises an OAM mode selection step of selecting a mode, the modulation step , an electromagnetic wave having a OAM mode selected by the OAM mode selecting step, and modulated based on the signal including the data in the first transmission step, emits electromagnetic waves having OAM mode that has been modulated by the modulation step.

  The present invention can receive OAM electromagnetic waves with higher accuracy than in the prior art by using the imaging action of the lens without increasing the aperture diameter of the antenna.

FIG. 1 illustrates an embodiment of a wireless communication system. It is a figure which shows an example of the transmitting antenna shown in FIG. FIG. 2 shows an example of the arrangement of a transmitting antenna, a receiving antenna and a beam control element shown in FIG. FIG. It is a figure which shows an example of distribution of the energy according to the radiation angle of the electromagnetic waves for every OAM mode radiated | emitted by the transmitting antenna shown in FIG. FIG. 7 illustrates another embodiment of a wireless communication system. It is a figure which shows an example of the transmitting antenna shown in FIG. It is a figure which shows an example of arrangement | positioning of the transmitting antenna shown in FIG. 5, a receiving antenna, and a beam control element. It is a figure which shows an example of the communication processing in the radio | wireless communications system shown in FIG.

  Hereinafter, embodiments will be described using the drawings.

  FIG. 1 illustrates one embodiment of a wireless communication system.

  The wireless communication system SYS illustrated in FIG. 1 includes a transmitting station 10, a receiving station 20, and a beam control element 30. The transmitting station 10 and the receiving station 20 are connected to each other via radio.

  The transmission station 10 includes an IF (Interface) unit 11, an S / P (Serial-to-Parallel) unit 12, a modulation unit 13, and a transmission antenna ANT.

  The IF unit 11 is an input interface or the like, and receives a signal including data transmitted from a mobile communication terminal such as a smartphone or a tablet terminal, or a signal including data from a network. The IF unit 11 outputs the received signal (hereinafter, also referred to as “transmission signal sequence”) to the S / P unit 12.

  The S / P unit 12 converts the transmission signal sequence from a serial signal to a parallel signal. The S / P unit 12 outputs the transmission signal sequence converted to the parallel signal to the modulation unit 13.

  The modulation unit 13 refers to the preamble added to the head of the transmission signal sequence received from the S / P unit 12 and acquires OAM information indicating the OAM mode for modulating the electromagnetic wave. Based on the acquired OAM information, the modulation unit 13 modulates each stream of the transmission signal sequence converted into the parallel signal into electromagnetic waves of OAM of different modes. Then, the modulation unit 13 multiplexes the electromagnetic waves of OAM in each mode and outputs the multiplexed electromagnetic waves to the transmission antenna ANT.

  Note that a processor or the like included in the transmission station 10 may function as an OAM mode selection unit that selects an OAM mode with reference to, for example, the preamble added to the beginning of the transmission signal sequence. In this case, the processor or the like outputs OAM information indicating the selected OAM mode to the modulation unit 13.

  The transmitting antenna ANT is a circular array antenna in which a plurality of antenna elements EA are arranged circumferentially, and has at least one set of circular array antennas. The transmitting antenna ANT radiates the OAM electromagnetic wave received from the modulator 13 toward the receiving station 20. The transmitting antenna ANT will be described with reference to FIG.

  The receiving station 20 has a receiving antenna ANR and a demodulator 21.

  The receiving antenna ANR, like the transmitting antenna ANT, is a circular array antenna in which a plurality of antenna elements EA are arranged on the circumference, and has at least one set of circular array antennas. The receiving antenna ANR receives the electromagnetic wave having the OAM emitted by the transmitting station 10 through the beam control element 30, and outputs the received signal of the received electromagnetic wave of the OAM to the demodulator 21. The receiving antenna ANR will be described with reference to FIG.

  The demodulation unit 21 performs demodulation processing on the received signal of the OAM electromagnetic wave. Then, the receiving station 20 outputs the transmission signal sequence to an external mobile communication terminal, a network, or the like, which is a transmission destination indicated by the preamble of the transmission signal sequence subjected to demodulation processing, through an output interface or the like included in the receiving station 20. Do.

  The beam control element 30 has, for example, a lens 31 of a convex lens. The beam control element 30 receives the electromagnetic wave transmitted from the transmitting antenna ANT of the transmitting station 10 using the lens 31, changes the radiation direction of the input electromagnetic wave, and outputs it. The lens 31 is a single convex lens, but may be a combination of a plurality of lenses. The lens 31 may be an element having the same function as that of the convex lens instead of the convex lens.

  The beam control element 30 may be included in the transmitting station 10 or the receiving station 20.

  The arrangement of the transmitting station 10, the receiving station 20, and the beam control element 30 will be described with reference to FIG.

  FIG. 2 shows an example of the transmitting antenna ANT shown in FIG. As shown in FIG. 2, the transmitting antenna ANT has N sets of circular array antennas SA (SA (1) -SA (N)). Each of the circular array antennas SA of the transmitting antenna ANT has different radii R1 (R11 to R1N) and is arranged concentrically. Then, for example, eight antenna elements EA are arranged at intervals of an angle 2π / 8 on the circumference of each circular array antenna SA. When the number of antenna elements EA included in each circular array antenna SA is M, the antenna elements EA are arranged at an interval of an angle 2π / M.

  The number N of sets of circular array antennas SA in the transmitting antenna ANT and the number of antenna elements EA included in each circular array antenna SA are appropriately determined according to the size of the wireless communication system SYS and the required quality of communication. Is preferred.

  Next, a method of modulating an electromagnetic wave having a mode of OAM using the transmission antenna ANT will be described. For example, the circular array antenna SA (n) (n is an integer of 1 to N) shown in FIG. 2 emits an electromagnetic wave having a single OAM mode j (j is an integer of 0 to M-1) In this case, each antenna element EA emits an electromagnetic wave of a signal waveform whose phase differs by 2πj / M. Thus, the circular array antenna SA (n) emits an electromagnetic wave of the OAM mode j.

  In addition, when radiating electromagnetic waves in two or more OAM modes, the circular array antenna SA (n) radiates from the antenna element an electromagnetic wave obtained by combining the signal waveforms of the respective OAM modes. For example, when the OAM mode is j1 and j2, the circular array antenna SA (n) has a signal waveform whose phase is different by 2πj1 / M for each antenna element EA and a signal waveform whose phase is different 2πj2 / M for each antenna element EA. And radiates an electromagnetic wave of a signal waveform synthesized from Thus, the circular array antenna SA (n) can simultaneously emit electromagnetic waves in the OAM modes j1 and j2. Note that j1 and j2 are integers from 0 to M-1.

  On the other hand, the receiving antenna ANR, like the transmitting antenna ANT shown in FIG. 2, has L sets of circular array antennas arranged concentrically with different radii R2 (R21-R2L). Then, similarly to the transmitting antenna ANT, eight antenna elements EA are arranged at intervals of an angle 2π / 8 on the circumference of each of the circular array antennas of the receiving antenna ANR. The number L of sets of circular array antennas of the receiving antenna ANR may be the same as or different from the number N of sets of circular array antennas of the transmitting antenna ANT. Further, the number of antenna elements EA included in each circular array antenna of the receiving antenna ANR may be the same as or different from the number of antenna elements EA included in each circular array antenna SA of the transmitting antenna ANT.

  The receiving antenna ANR is any one of the receiving antenna ANR that receives the electromagnetic wave of OAM emitted by the circular array antenna SA (n) (n is an integer from 1 to N) of the transmitting antenna ANT via the beam control element 30. Receive with a set of circular array antennas. The receiving antenna ANR outputs the received signal of the received electromagnetic wave to the demodulator 21.

  When the electromagnetic wave of OAM is in a single OAM mode, the demodulation unit 21 processes the phase shift so that the phases of the received signals are aligned between the antenna elements EA of the circular array antenna of the receiving antenna ANR that has received the electromagnetic wave of OAM. Run. The demodulation unit 21 restores the modulation signal by adding the signal waveforms of the reception signals of the respective antenna elements EA whose phases are aligned with each other. Then, the demodulation unit 21 demodulates the restored modulated signal.

  On the other hand, when the electromagnetic wave of OAM has a plurality of OAM modes, the demodulator 21 receives IDFT (received at the same time in each antenna element EA of the circular array antenna of the receiving antenna ANR which has received the electromagnetic wave of OAM). Inverse discrete Fourier transform) processing is performed to separate received signals in each OAM mode. Then, the demodulator 21 demodulates the separated received signals in each of the OAM modes.

  FIG. 3 shows an example of the arrangement of the transmitting antenna ANT, the receiving antenna ANR and the beam control element 30 shown in FIG. In FIG. 3, a set of circular array antennas of radius R11 (ie, the circular array antenna SA (1) shown in FIG. 2) is shown as a transmit antenna ANT, and a set of circular arrays of radius R21 is shown as a receive antenna ANR. Indicates an antenna. Further, in FIG. 3, a lens 31 having a diameter dL and a focal length f is shown as the beam control element 30. The diameter dL of the lens 31 is preferably set according to the beam width of the electromagnetic wave emitted from the transmission antenna ANT.

  In FIG. 3, the direction of the optical axis of the lens 31 is taken as the X axis, and the directions perpendicular to the direction of the optical axis of the lens 31 are taken as the Y axis and the Z axis. Then, in FIG. 3, the transmission antenna ANT is disposed on the YZ plane so that the origin of the XYZ coordinates coincides with the center of the circular array antenna SA (1) of the transmission antenna ANT. In addition, the receiving antenna ANR is disposed in the YZ plane at a distance x so as to face the transmitting antenna ANT so that the X axis passes through the center of the circular array antenna included in the receiving antenna ANR. That is, the center of the transmitting antenna ANT, the center of the receiving antenna ANR, and the optical axis of the lens 31 are disposed on the X axis.

  When the electromagnetic wave emitted by the transmitting antenna ANT is imaged at the position of the distance x at which the receiving antenna ANR is arranged, by the lens 31 of the focal distance f arranged at the position a distant from the transmitting antenna ANT, The condition of 1) is satisfied.

1 / a + 1 / (x-a) = 1 / f (1)
The magnification k of the image of the transmitting antenna ANT formed at the position of the receiving antenna ANR is calculated using the equation (2).

k = (x-a) / a (2)
When the size of the image of the transmitting antenna ANT of radius R11 is the size of the receiving antenna ANR of radius R21, the magnification k is R21 / R11. Accordingly, the distance a at which the lens 31 is disposed is expressed as Expression (3) using Expression (2) and the radii R11 and R21 of the transmission antenna ANT and the reception antenna ANR.

a = x × R11 / (R11 + R21) (3)
Further, the focal length f of the lens 31 is related to the radius R11 of the transmitting antenna ANT and the radius R21 of the receiving antenna ANR as in the equation (4) based on the equations (1) and (3).

f = x x R11 / (R11 + R21) x (1-R11 / (R11 + R21)) (4)
That is, each of the transmitting antenna ANT, the receiving antenna ANR, and the beam control element 30 is disposed on the X axis so as to satisfy the conditions of equations (3) and (4).

  Although FIG. 3 shows the case where the transmitting antenna ANT uses a circular array antenna of radius R11 and the receiving antenna ANR uses a circular array antenna of radius R21, each of the transmitting antenna ANT and the receiving antenna ANR has another radius Also in the case of using the circular array antenna of the above, the distance a and the focal distance f of the lens 31 are calculated using the equations (1) and (2).

  A circular array antenna SA (i) of radius R1i of the transmitting antenna ANT and a circular array antenna of radius R2m of the receiving antenna ANR which satisfy the conditions of the equations (3) and (4) are R2m = k × When the condition of R1i is satisfied, communication between the circular array antenna SA (1) of radius R11 of the transmitting antenna ANT and the circular array antenna of radius R21 of the receiving antenna ANR, and the circular array antenna SA of radius R1i of the transmitting antenna ANT Communication between (i) and a circular array antenna of radius R2 m of the receiving antenna ANR may be performed simultaneously. Here, i is an integer of 2 or more and N or less, and m is an integer of 2 or more and L or less.

  In this case, the electromagnetic wave radiated from the circular array antenna SA (1) of the transmitting antenna ANT is received by the circular array antenna of radius R21 of the receiving antenna ANR, and is input to the demodulator 21. On the other hand, the electromagnetic wave radiated from the circular array antenna SA (i) of the transmitting antenna ANT is received by the circular array antenna of radius R 2 m of the receiving antenna ANR, and is input to the demodulator 21. The demodulation unit 21 independently demodulates the reception signal input from the circular array antenna of radius R21 of the reception antenna ANR and the reception signal input from the circular array antenna of radius R2 m.

  FIG. 4 shows an example of energy distribution according to the radiation angle of the electromagnetic wave for each OAM mode radiated by the transmission antenna ANT shown in FIG. The horizontal axis in FIG. 4 indicates the radiation angle θ of the electromagnetic wave of OAM emitted by the transmission antenna ANT with reference to the direction of the X axis (the optical axis of the lens 31). The vertical axis in FIG. 4 represents the energy ratio between the total radiation energy of the electromagnetic wave emitted by the transmitting antenna ANT and the accumulated value of the radiation energy of the electromagnetic wave radiated at the radiation angle from 0 degrees to θ degrees.

  In order to obtain the distribution shown in FIG. 4, the number of antenna elements EA of the circular array antenna of radius R11 of the transmitting antenna ANT and the circular array antenna of radius R21 of the receiving antenna ANR is twelve. Further, the frequency of the electromagnetic wave of OAM is 60 GHz, the radius R11 is 0.5 cm (that is, one wavelength of the electromagnetic wave), and the radius R21 is 10 cm. In addition, the distance x between the transmitting antenna ANT and the receiving antenna ANR is 10 meters, and the transmitting station 10, the receiving station 20 and the beam control element 30 are at a height of 0.125 centimeters (0.25 wavelength) from the ground. It is supposed to be deployed.

  As shown in FIG. 4, for example, when the OAM mode is "1", the radiation angle θ at which the energy ratio is 80 percent indicates 27 degrees. When the radiation angle θ is 27 degrees and the beam control element 30 is not disposed, the beam width of the electromagnetic wave of OAM mode “1” at the position of 10 meters where the receiving antenna ANR is disposed is 5.09 meters. However, when the lens 31 whose focal length f is 45.35 centimeters is disposed at a position of 47.62 centimeters (distance a) from the transmitting antenna ANT, the OAM mode “1” at the location where the receiving antenna ANR is disposed The beam width of the electromagnetic wave is 10 centimeters (ie, radius R21 of the receiving antenna ANR). That is, by disposing the beam control element 30, the spread of the electromagnetic wave in the OAM mode "1" can be reduced by 0.020 times. Further, the spread of the electromagnetic wave when the OAM mode is “0”, “2”, “3” can be reduced as in the case of the OAM mode “1”. Thereby, the scale of the wireless communication system SYS can be suppressed.

  The diameter dL of the lens 31 when the OAM mode is “1” is preferably larger than 2 × 47.62 centimeters (distance a) × tan (27 degrees) (that is, 48.53 centimeters).

  As described above, in the embodiment shown in FIGS. 1 to 4, the beam control element 30 is disposed such that the size of the image of the transmission antenna ANT is equal to the size of the reception antenna ANR at the position where the reception antenna ANR is disposed. . That is, the beam width of the electromagnetic wave of OAM radiated from the transmitting antenna ANT can be made the size of the receiving antenna ANR by the imaging action of the lens 31 of the beam control element 30. As a result, the wireless communication system SYS can receive the electromagnetic waves of OAM with higher accuracy than in the conventional case without increasing the aperture diameter of the receiving antenna ANR, and can reduce the size of the wireless communication system SYS.

  FIG. 5 shows another embodiment of a wireless communication system. In addition, about the element which has the same or similar function as the element demonstrated in FIG. 1, the same or similar code | symbol is attached | subjected, and detailed description is abbreviate | omitted about these.

  The wireless communication system SYS1 illustrated in FIG. 5 includes a transmitting station 10A, a receiving station 20A, and a beam control element 30.

  The transmission station 10A includes an IF unit 11, an S / P unit 12, a modulation unit 13, a control unit 14, a reference signal generation unit 15, and a transmission antenna ANTa.

  The control unit 14 is realized, for example, by a processor or the like included in the transmission station 10A executing a control program stored in a storage device such as a hard disk device included in the transmission station 10A, and controls the operation of the transmission station 10A. Do. For example, the control unit 14 may use the IF unit 11 or the IF unit to measure the signal-to-noise ratio (SNR) or the BER (Bit Error Rate) of the electromagnetic wave received by the receiving antenna 20A measured by the receiving station 20A. The signal is received via an input interface included in a transmitting station 10A different from the one 11 shown in FIG. The control unit 14 selects, based on the received measurement result, a set of circular array antennas that radiates an electromagnetic wave of OAM among a plurality of sets of circular array antennas included in the transmission antenna ANTa. Further, the control unit 14 causes the reference signal generation unit 15 to generate a reference signal that causes the reception station 20A to measure the SNR, BER, and the like of the electromagnetic wave emitted by the transmission antenna ANTa. Then, the control unit 14 sequentially transmits the OAM electromagnetic waves modulated based on the generated reference signal to each of a plurality of sets of circular array antennas of the transmission antenna ANTa.

  A processor or the like included in the transmitting station 10A may function as, for example, an OAM mode selection unit that selects an OAM mode with reference to the preamble added to the beginning of the transmission signal sequence. In this case, the processor or the like outputs OAM information indicating the selected OAM mode to the modulation unit 13.

  The reference signal generation unit 15 generates a reference signal for causing the receiving station 20A to measure the SNR, BER, etc. of the electromagnetic waves radiated by each circular array antenna of the transmission antenna ANTa based on the control instruction from the control unit 14. , The generated reference signal is output to the transmitting antenna ANTa.

  The transmitting antenna ANTa is a circular array antenna in which a plurality of antenna elements EA are arranged on the circumference, and has a plurality of sets of circular array antennas. The transmission antenna ANTa is selected by the modulation unit 13 based on a transmission signal sequence received through the IF unit 11 using a pair of circular array antennas selected by the control unit 14 among a plurality of circular array antennas. It emits modulated OAM electromagnetic waves. In addition, the transmission antenna ANTa radiates the electromagnetic wave of the reference signal generated by the reference signal generation unit 15 to each of the plurality of sets of circular array antennas based on the control instruction of the control unit 14. The transmitting antenna ANTa will be described with reference to FIG.

  The receiving station 20A has a receiving antenna ANRa, a demodulator 21 and a measuring unit 22.

  The receiving antenna ANRa, like the transmitting antenna ANTa, is a circular array antenna in which a plurality of antenna elements EA are arranged on the circumference, and has at least one set of circular array antennas. The receiving antenna ANRa receives the electromagnetic wave having the OAM emitted by the transmitting station 10A through the beam control element 30, and outputs the received signal of the received electromagnetic wave of the OAM to the demodulator 21. Further, when the electromagnetic wave emitted by the transmitting station 10A is a reference signal, the receiving antenna ANRa outputs the received signal of the received electromagnetic wave to the measuring unit 22. The receiving antenna ANRa will be described with reference to FIG.

  Preferably, the receiving station 20A uses a variable phase shifter or the like to compensate for phase distortion occurring in the received signal due to the imaging action, and then output the received signal to the demodulator 21 and the measurer 22.

  The measurement unit 22 measures the SNR, the BER, and the like of the reception signal of the electromagnetic wave of the reference signal which is radiated by each circular array antenna of the transmission antenna ANTa of the transmission station 10A and is received by the reception antenna ANRa. The measurement unit 22 feeds back the measurement result to the transmitting station 10A in a wired or wireless manner via an output interface or the like included in the receiving station 20A. The SNR, the BER, and the like are examples of the reception state.

  FIG. 6 shows an example of the transmitting antenna ANTa shown in FIG. FIG. 6 shows, for example, six sets of circular array antennas SAa having a radius R11 or a radius R12 among N sets of circular array antennas SAa (SAa (1) -SAa (N)) included in the transmission antenna ANTa. Each of the circular array antennas SAa of the transmitting antenna ANTa is arranged on the YZ plane perpendicular to the optical axis (X axis) of the lens 31 so that the centers of the respective circular array antennas SAa do not overlap. For example, the circular array antenna SAa (2) is arranged at a distance h from the center of the circular array antenna SAa (1) and at an angle φ with respect to the Y axis. Then, eight antenna elements EA are arranged at intervals of an angle 2π / 8 on the circumference of each circular array antenna SAa, similarly to the circular array antenna SA shown in FIG.

  The radii of the circular array antennas SAa may be all the same or all different. In addition, the number N of sets of circular array antennas in the transmitting antenna ANTa and the number of antenna elements EA of each circular array antenna are appropriately determined according to the size of the radio communication system SYS1 and the required quality of communication. preferable.

  On the other hand, the receiving antenna ANRa has a plurality of sets of circular array antennas in the same manner as the transmitting antenna ANTa shown in FIG. 6, and each circular array antenna has a distance x so that the centers of the respective circular array antennas do not overlap each other. Placed on the YZ plane at Then, in each of the circular array antennas of the receiving antenna ANRa, eight antenna elements EA are circumferentially arranged at an angle 2π / 8, as in the case of the transmitting antenna ANTa. The number of sets of circular array antennas of the receiving antenna ANRa may be the same as or different from the number of sets of circular array antennas of the transmitting antenna ANTa. Further, the number of antenna elements EA included in each circular array antenna of the receiving antenna ANRa may be the same as or different from the number of antenna elements EA included in each circular array antenna of the transmitting antenna ANTa. Furthermore, the radius of each circular array antenna of the receiving antenna ANRa may be all the same or all different.

  FIG. 7 shows an example of the arrangement of the transmitting antenna ANTa, the receiving antenna ANRa and the beam control element 30 shown in FIG. The same or similar elements as or to the elements described with reference to FIG.

  In FIG. 7, two sets of circular array antennas SAa (1) and SAa (2) of radius R11 are shown as transmitting antennas ANTa, and one set of circular arrays of radius R21 is shown as receiving antenna ANRa.

  Further, in FIG. 7, the circular array antenna SAa (1) of the transmitting antenna ANTa is disposed on the YZ plane such that the origin of the XYZ coordinates coincides with the center of the circular array antenna SAa (1). Further, as shown in FIG. 6, the circular array antenna SAa (2) is disposed on the YZ plane such that the center of the circular array antenna SAa (2) is located at the distance h and the angle φ. On the other hand, the receiving antenna ANRa is opposed to the circular array antenna SAa (1) of the transmitting antenna ANTa so that the X axis passes through the center of the circular array antenna of the receiving antenna ANRa, as in the receiving antenna ANR shown in FIG. In the YZ plane. That is, the center of the circular array antenna SA (1) of the transmitting antenna ANTa, the center of the receiving antenna ANRa, and the optical axis of the lens 31 are disposed on the X axis. In addition, the transmission antenna ANTa, the reception antenna ANRa, and the lens 31 are disposed so as to satisfy the conditions of Expression (3) and Expression (4).

  In this case, the electromagnetic wave of the OAM radiated by the circular array antenna SAa (1) of the transmitting antenna ANTa shown in FIG. 7 is located at the position where the receiving antenna ANRa is arranged, similarly to the transmitting antenna ANT shown in FIG. An image is formed by the lens 31 with the size of the radius R21. On the other hand, since the circular array antenna SAa (2) shown in FIG. 7 is disposed at the offset position of the distance h and the angle φ with respect to the optical axis (X axis) of the lens 31, the circular array antenna SAa (2) The electromagnetic wave of the OAM emitted by) forms an image 40 at a position different from the position of the antenna ANta. For this reason, it becomes difficult for the electromagnetic waves of OAM radiated by the circular array antenna SAa (2) to be received by the receiving antenna ANRa with predetermined receiving power.

  When the offset of image 40 with respect to the position of antenna ANTa is distance h ′ and angle φ ′, the distance between image 40 and circular array antenna SAa (2) of transmitting antenna ANTa is h ′ = (x−a) × It is related to h / a and the angle φ ′ = π + φ.

  For example, when the position of the receiving station 20A is shifted due to a disaster such as an earthquake or an artificial action, and the position of the receiving antenna ANRa becomes the position of the image 40, the receiving antenna ANRa is a circular array antenna SAa of the transmitting antenna ANTa. It becomes difficult to receive OAM electromagnetic waves radiated by (1) with predetermined reception power. On the other hand, the receiving antenna ANRa can receive the electromagnetic wave of OAM radiated by the circular array antenna SAa (2) of the transmitting antenna ANTa with predetermined receiving power. That is, as shown in FIG. 6, the transmitting antenna ANTa distributes and arranges each of the N sets of circular array antennas SAa on the YZ plane, whereby the receiving antenna ANRa of the receiving station 20A is any of the transmitting antennas ANTa. It can receive OAM electromagnetic waves emitted by a set of circular array antennas SAa.

  Therefore, the control unit 14 generates a reference signal to the reference signal generation unit 15 in order to select one set of circular array antennas SAa that radiates the electromagnetic wave of OAM among the N sets of circular array antennas SAa of the transmission antennas ANTa. Let Then, the control unit 14 sequentially transmits the OAM electromagnetic waves modulated based on the reference signal generated by the reference signal generation unit 15 to each of the N sets of circular array antennas SAa of the transmission antenna ANTa. The control unit 14 receives, from the receiving station 20A, the measurement results by the measurement unit 22 such as the SNR and the BER of the electromagnetic waves radiated by the respective circular array antennas SAa of the transmission antenna ANTa. For example, the control unit 14 selects the circular array antenna SAa in which the highest SNR (or the lowest BER) is measured, with reference to the received measurement result.

  FIG. 8 shows an example of communication processing in the wireless communication system SYS1 shown in FIG. For example, the process of steps S100 to S170 is performed by the transmitting station 10A. Also, the processing from step S200 to step S240 is executed by the receiving station 20A. That is, FIG. 8 shows an embodiment of a communication method of the wireless communication system.

  The process shown in FIG. 8 is started when the transmitting station 10A receives a transmission signal sequence.

  In step S100, the control unit 14 causes the reference signal generation unit 15 to generate a reference signal.

  In step S110, the control unit 14 causes the OAM electromagnetic waves modulated based on the reference signal generated in step S100 to be sequentially transmitted to each of the circular array antennas SAa (1) -SAa (N) of the transmission antenna ANTa. Therefore, initialize the variable i to 1.

  In step S120, the control unit 14 causes the circular array antenna SAa (i) to radiate the OAM electromagnetic wave modulated based on the reference signal generated in step S100.

  In step S130, the control unit 14 receives, from the receiving station 20A, measurement results such as SNR and BER for the electromagnetic wave emitted in step S120. Then, the control unit 14 stores the received measurement result in the storage device of the transmitting station 10A in association with the circular array antenna SAa (i).

  In step S140, the control unit 14 increments the variable i by one.

  In step S150, the control unit 14 determines whether the variable i is smaller than the number N of sets of circular array antennas SAa. If the variable i is smaller than the number of sets N, the process of the transmitting station 10A proceeds to step S120. On the other hand, when the variable i is equal to or more than the number of sets N, the process of the transmitting station 10A proceeds to step S160.

  In step S160, the control unit 14 selects a circular array antenna SAa that radiates the electromagnetic wave of the transmission signal series OAM based on the measurement result of each circular array antenna SAa received in step S130. For example, the control unit 14 selects the circular array antenna SAa for which the highest SNR has been measured. Alternatively, the control unit 14 selects the circular array antenna SAa for which the lowest BER has been measured.

  In step S170, the control unit 14 causes the circular array antenna SAa of the transmission antenna ANTa selected in step S160 to emit an electromagnetic wave having the OAM modulated by the modulation unit 13 based on the transmission signal sequence. Then, the transmitting station 10A ends the communication process.

  Each time the transmission station 10A receives a transmission signal sequence, the transmission station 10A executes the processing from step S100 to step S170. Note that, for example, when the measurement unit 22 measures the SNR and the like of the reception signal of the transmission signal sequence, the transmitting station 10A refers to the measured SNR and the like and determines that the predetermined communication quality is maintained. The process from step S100 to step S150 may be omitted.

  On the other hand, in step S200, the receiving antenna ANRa receives the electromagnetic wave of the OAM, which is modulated based on the reference signal, emitted in step S120. Then, the receiving antenna ANRa outputs the received signal of the received electromagnetic wave to the measuring unit 22.

  In step S210, the measurement unit 22 measures the SNR, BER, and the like of the received signal of the electromagnetic wave received in step S200.

  In step S220, the measurement unit 22 transmits the measurement result measured in step S210 to the transmission station 10A.

  In step S230, the receiving antenna ANRa receives the electromagnetic wave of the OAM that is modulated based on the transmission signal sequence emitted in step S170. Then, the receiving antenna ANRa outputs the received signal of the received electromagnetic wave to the demodulator 21.

  In step S240, the demodulation unit 21 performs demodulation processing on the received signal of the electromagnetic wave received in step S230. Then, the demodulation unit 21 outputs the transmission signal sequence to an external mobile communication terminal, a network, or the like, which is a transmission destination indicated by the preamble of the transmission signal sequence subjected to demodulation processing, through an output interface or the like included in the receiving station 20. . Then, the receiving station 20A ends the communication process.

  The receiving station 20A executes the process from step S200 to step S240 every time the transmitting station 10A receives the transmission signal sequence.

  As described above, in the embodiments shown in FIG. 5 to FIG. 8, the beam control element 30 is disposed such that the size of the image of the transmission antenna ANTa becomes the size of the reception antenna ANRa at the position where the reception antenna ANRa is disposed. . That is, the beam width of the electromagnetic wave of OAM radiated from the transmitting antenna ANTa can be made the size of the receiving antenna ANRa by the imaging action of the lens 31 which the beam control element 30 has. As a result, the radio communication system SYS1 can receive the electromagnetic waves of OAM with higher accuracy than in the conventional case without increasing the aperture diameter of the receiving antenna ANRa, and the scale of the communication system SYS1 can be suppressed.

  Further, each of the N sets of circular array antennas SAa of the transmitting antenna ANTa is arranged on a two-dimensional plane perpendicular to the optical axis of the lens 31 so that the centers of the respective circular array antennas SAa do not overlap. Then, when transmitting the transmission signal sequence, the control unit 14 uses the reference signal from the reference signal generation unit 15 and the circular array antenna with the highest SNR (or lowest BER) of the electromagnetic wave received by the receiving station 20A. Select SAa. Thereby, even when the position of the receiving station 20A is shifted due to a disaster or the like, the wireless communication system SYS1 can transmit the transmission signal sequence.

  The features and advantages of the embodiments will be apparent from the foregoing detailed description. This is intended to cover the features and advantages of the embodiments as described above without departing from the spirit and scope of the claims. Also, all modifications and variations should be readily apparent to those skilled in the art. Accordingly, there is no intention to limit the scope of the embodiments having the invention to those described above, and it is also possible to rely on appropriate modifications and equivalents included in the scope disclosed in the embodiments.

10, 10A: transmitting station; 11: IF unit; 12: S / P unit; 13: modulation unit; 14: control unit; 15: reference signal generation unit; 20, 20A: reception station; 21: demodulation unit; 30 measurement unit 30 beam control element 31 lens 40 image ANT, ANTa transmit antenna ANR, ANRa receive antenna EA antenna element SA (1)-SA (N), SAa (1) -SAa (N) ... circular array antenna; SYS, SYS 1 ... wireless communication system

Claims (8)

A wireless communication system comprising a transmitting station, a receiving station, and a beam control element, comprising:
The transmitting station is
A modulation unit that modulates an electromagnetic wave based on a signal including data to be transmitted;
A transmitting antenna unit including a plurality of sets of transmitting circular array antennas having a plurality of transmitting antenna elements for emitting the electromagnetic waves modulated by the modulation unit;
The beam control element
As input electromagnetic wave radiated from the previous SL transmitting antenna unit, by changing the radial direction of the input electromagnetic wave comprises a lens unit for outputting,
The receiving station is
A receiving antenna unit including a plurality of sets of receiving circular array antennas having a plurality of receiving antenna elements for receiving an electromagnetic wave output from the lens unit;
And a demodulation unit that demodulates a reception signal of the electromagnetic wave received by the reception antenna unit ,
The transmitting antenna unit has a plurality of sets of transmitting circular array antennas arranged on a two-dimensional plane perpendicular to the optical axis direction of the lens unit,
The receiving antenna unit includes a plurality of sets of the receiving circular array antenna disposed on a two-dimensional plane perpendicular to the optical axis direction of the lens unit.
The transmitting station is
A signal generation unit that generates a reference signal that causes each of the transmission circular array antennas to emit an electromagnetic wave;
A control unit that causes each of the transmission circular array antennas to emit an electromagnetic wave of the reference signal;
The receiving station is
A measurement unit configured to measure the reception state of the electromagnetic wave of the reference signal received by the reception antenna unit for each of the transmission circular array antennas, and output the measurement result to the transmission station;
The wireless communication system , wherein the control unit selects a transmission circular array antenna for emitting an electromagnetic wave of a signal including the data from a plurality of sets of the transmission circular array antennas based on the result of the measurement . In the wireless communication system according to claim 1,
The lens unit, the image of the electromagnetic wave radiated from the transmission Shinen shaped array antenna, at a position where the receiving antenna unit is arranged so as to form an image with the size of the receiving Shinen shaped array antenna, wherein A wireless communication system, wherein the wireless communication system is disposed between a transmitting antenna unit and the receiving antenna unit. In the wireless communication system according to claim 1,
The transmitting antenna unit has a plurality of sets of transmitting circular array antennas arranged concentrically on a two-dimensional plane perpendicular to the optical axis direction of the lens unit,
The receiving antenna unit has a plurality of sets of the receiving circular array antennas arranged concentrically on a two-dimensional plane perpendicular to the optical axis direction of the lens unit,
The lens unit, the image of the electromagnetic waves radiated from each of the multiple sets of the transmitting circular array antenna, at a position where the receiving antenna unit is disposed, either the size of the double sets of said receiving circular antenna arrays A wireless communication system, wherein the wireless communication system is disposed between the transmitting antenna unit and the receiving antenna unit so as to form an image at a short distance. The wireless communication system according to any one of claims 1 to 3 .
The transmitting station includes an OAM mode selection unit that selects an orbital angular momentum (OAM) mode to be modulated in the modulation unit based on information added to a signal including the data.
The modulation unit modulates an electromagnetic wave having the OAM mode selected by the OAM mode selection unit based on a signal including the data.
The wireless communication system according to claim 1, wherein the transmission antenna unit radiates an electromagnetic wave having an OAM mode modulated by the modulation unit. A communication method of a wireless communication system comprising a transmitting station, a receiving station, and a beam control element, comprising:
A modulation step in which the transmitting station modulates an electromagnetic wave based on a signal including data to be transmitted;
A first transmission step in which the transmitting station radiates the modulated electromagnetic wave using a transmitting antenna unit including a plurality of sets of transmitting circular array antennas having a plurality of transmitting antenna elements;
An imaging step in which the beam control element receives an electromagnetic wave emitted from the transmission antenna part using a lens part included in the own element, changes a radiation direction of the input electromagnetic wave, and outputs the changed electromagnetic wave;
A first receiving step of receiving the electromagnetic wave output from the lens unit using the receiving antenna unit including a plurality of sets of receiving circular array antennas having a plurality of receiving antenna elements;
And a demodulation step of demodulating the reception signal of the electromagnetic wave received by the reception antenna unit .
The transmitting antenna unit has a plurality of sets of transmitting circular array antennas arranged on a two-dimensional plane perpendicular to the optical axis direction of the lens unit,
The receiving antenna unit includes a plurality of sets of the receiving circular array antenna disposed on a two-dimensional plane perpendicular to the optical axis direction of the lens unit.
A second transmitting step in which the transmitting station causes each of the transmitting circular array antennas to emit an electromagnetic wave of a reference signal;
A second receiving step in which the receiving station receives an electromagnetic wave of the reference signal emitted by each of the transmitting circular array antennas using the receiving antenna unit;
Measuring the reception state of the electromagnetic wave of the reference signal received by the reception antenna unit for each of the transmission circular array antennas, and outputting the measurement result to the transmission station;
Selecting, from the plurality of sets of transmission circular array antennas, a transmission circular array antenna that causes the transmitting station to emit an electromagnetic wave of a signal including the data based on the result of the measurement received from the receiving station;
A communication method of a wireless communication system , further comprising : In the communication method of the wireless communication system according to claim 5 ,
The lens unit, the image of the electromagnetic wave radiated from the transmission Shinen shaped array antenna, at a position where the receiving antenna unit is arranged so as to form an image with the size of the receiving Shinen shaped array antenna, wherein A communication method of a wireless communication system, which is disposed between a transmitting antenna unit and the receiving antenna unit. In the communication method of the wireless communication system according to claim 5 ,
The transmitting antenna unit has a plurality of sets of transmitting circular array antennas arranged concentrically on a two-dimensional plane perpendicular to the optical axis direction of the lens unit,
The receiving antenna unit has a plurality of sets of the receiving circular array antennas arranged concentrically on a two-dimensional plane perpendicular to the optical axis direction of the lens unit,
The lens unit, the image of the electromagnetic waves radiated from each of the multiple sets of the transmitting circular array antenna, at a position where the receiving antenna unit is disposed, either the size of the double sets of said receiving circular antenna arrays A communication method of a wireless communication system, which is disposed between the transmitting antenna unit and the receiving antenna unit so as to form an image at a short distance. The communication method of a wireless communication system according to any one of claims 5 to 7 .
The transmitting station includes an OAM mode selection step of selecting an Orbital Angular Momentum (OAM) mode to be modulated based on information added to a signal including the data.
In the modulation step , the electromagnetic wave having the OAM mode selected in the OAM mode selection step is modulated based on the signal including the data,
In the first transmission step , the electromagnetic wave having the OAM mode modulated in the modulation step is radiated.

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