Transmitting device and transmitting method

Abstract

This transmission device comprises: a lattice point array antenna provided with a plurality of antenna elements on a polyhedron; and a control unit that selects, as a UCA and from the plurality of antenna elements in the lattice point array antenna, a plurality of antenna elements existing on a discretionary circle, and that causes the selected UCA to perform OAM transmission.

Description

[Technical field]

[0001] The present invention relates to a technique for spatially multiplexing and transmitting wireless signals using the orbital angular momentum (OAM) of electromagnetic waves. [Background technology]

[0002] In recent years, in order to improve transmission capacity, spatial multiplexing transmission technology of radio signals using OAM has been studied (for example, Non-Patent Document 1). In electromagnetic waves with OAM, equiphase surfaces are distributed in a spiral shape along the propagation direction centered on the propagation axis. Since electromagnetic waves with different OAM modes propagating in the same direction have orthogonal spatial phase distributions in the direction of the rotation axis, it is possible to multiplex and transmit signals by separating the signals of each OAM mode modulated with different signal sequences at the receiving station.

[0003] In a wireless communication system using this OAM multiplexing technology, a uniform circular array antenna (hereinafter referred to as UCA (Uniform Circular Array)) in which multiple antenna elements are arranged at equal intervals in a circle is used to generate, combine, and transmit multiple OAM modes, thereby achieving spatial multiplexing transmission of different signal sequences (for example, Non-Patent Document 2). For example, a Butler circuit (Butler matrix circuit) is used to generate signals for multiple OAM modes. However, the use of a Butler circuit is just one example.

[0004] In addition, signals of the same OAM mode can be multiplexed and transmitted by multiple UCAs of different diameters arranged concentrically. On the receiving side, multiplexed signals in the same OAM mode can be separated by MIMO technology. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] J. Wang et al., "Terabit free-space data transmission employing orbital angular momentum multiplexing," Nature Photonics, Vol.6, pp.488-496, July 2012. [Non-Patent Document 2] Y. Yan et al., "High-capacity millimeter-wave communications with orbital angular momentum multiplexing," Nature Commun., vol.5, p.4876, Sep. 2014. Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, transmission equipment using UCA enables large-capacity communications, but in the future, it will be desirable to support mobile communications. In order to apply OAM multiplexing transmission technology to mobile communications, multi-directional support and mobility tracking capabilities are required to transmit signals in multiple directions.

[0007] However, with conventional wireless transmission technology using UCA, in order to separate multiple OAM mode signals without interference between the modes, the transmitting antenna and the receiving antenna must be installed in opposing positions directly in front of each other, and axial alignment is required, which results in issues such as incompatibility with multiple directions and poor movement tracking.

[0008] The present invention has been made in consideration of the above-mentioned points, and has an object to provide a technique that enables multi-directional support and movement tracking in a transmitting device using UCA. [Means for solving the problem]

[0009] According to the disclosed technology, there is provided a lattice point array antenna having a plurality of antenna elements on a polyhedron, a control unit that selects a plurality of antenna elements present on an arbitrary circle from the plurality of antenna elements in the lattice point array antenna as a UCA and causes OAM transmission to be performed by the selected UCA; The control unit orients each antenna element constituting the selected UCA in a transmission direction. A transmitting device is provided. Effect of the Invention

[0010] According to the disclosed technology, a technology is provided that enables multi-directional support and movement tracking in a transmitting device using UCA. [Brief description of the drawings]

[0011] [Figure 1] FIG. 13 is a diagram illustrating an example of phase setting of a UCA for generating an OAM mode signal. [Diagram 2] 1A to 1C are diagrams illustrating examples of phase distribution and signal intensity distribution of an OAM multiplexed signal. [Diagram 3] FIG. 1 is a diagram showing an example of an antenna configuration having multiple UCAs arranged concentrically. [Figure 4] FIG. 1 is a diagram for explaining a basic concept of a technique according to an embodiment of the present invention. [Diagram 5] 1 is a diagram showing an example of a lattice point array antenna according to an embodiment of the present invention; [Figure 6] 1A and 1B are diagrams illustrating examples of arrangements of antenna elements according to an embodiment of the present invention. [Figure 7] FIG. 2 is a diagram for explaining an antenna element. [Figure 8] 1 is a diagram showing an example of a lattice point array antenna according to an embodiment of the present invention; [Figure 9] FIG. 2 is a diagram illustrating a configuration example of a transmitting device according to an embodiment of the present invention. [Figure 10] FIG. 2 is a diagram illustrating a configuration example of a transmitting device according to an embodiment of the present invention. [Figure 11] FIG. 2 is a diagram illustrating a configuration example of a transmitting device according to an embodiment of the present invention. [Figure 12]2 is a diagram illustrating an example of the configuration of a changeover switch unit 30. FIG. [Figure 13] 2 is a diagram illustrating an example of the configuration of an OAM mode generation unit 40. FIG. [Figure 14] 4 is a flowchart showing a flow of signal processing. [Figure 15] FIG. 13 is a diagram showing an example of transmission by a selected UCA. [Figure 16] FIG. 13 is a diagram showing an example of transmission by a selected UCA. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention (the present embodiment) will be described with reference to the drawings. The embodiment described below is merely an example, and the embodiment to which the present invention is applied is not limited to the following embodiment.

[0013] (Basic operation example) First, a basic setting and operation example relating to UCA used in the transmitting device in this embodiment will be described.

[0014] Figure 1 shows an example of phase setting of a UCA for generating an OAM mode signal. The UCA shown in Figure 1 is a UCA consisting of eight antenna elements.

[0015] In Fig. 1, signals of OAM modes 0, 1, 2, 3, ... on the transmitting side are generated by the phase difference of the signals supplied to each antenna element (indicated by ●) of the UCA. In other words, a signal of OAM mode n is generated by setting the phase of the signal supplied to each antenna element so that the phase rotates n times (n x 360 degrees). For example, when the UCA is composed of m = 8 antenna elements as shown in Fig. 1 and a signal of OAM mode n = 2 is generated, a phase difference of 360n / m = 90 degrees (0 degrees, 90 degrees, 180 degrees, 270 degrees, 0 degrees, 90 degrees, 180 degrees, 270 degrees) is set counterclockwise for each antenna element so that the phase rotates two times as shown in Fig. 1 (3).

[0016] Note that a signal with the phase rotation direction reversed to that of an OAM mode n signal is called OAM mode -n. For example, the phase rotation direction of a positive OAM mode signal is counterclockwise, and the phase rotation direction of a negative OAM mode signal is clockwise.

[0017] By generating different signal sequences as signals of different OAM modes and transmitting the generated signals simultaneously, wireless communication can be performed using spatial multiplexing in which multiple OAM modes are multiplexed. Also, the same signal sequence may be generated as signals of different OAM modes and the generated signals may be transmitted simultaneously.

[0018] In order to separate the OAM multiplexed signals on the receiving side, the phase of each antenna element of the UCA on the receiving side is set to be opposite to the phase of the antenna elements on the transmitting side.

[0019] Figure 2 shows examples of phase distribution and signal intensity distribution of OAM multiplexed signals. In Figures 2(1) and (2), the arrows represent the phase distribution of OAM mode 1 and OAM mode 2 signals as viewed from the end face (orthogonal propagation plane) perpendicular to the propagation direction from the transmitting side. The arrows start at 0 degrees, the phase changes linearly, and end at 360 degrees. In other words, an OAM mode n signal propagates while its phase rotates n times (n x 360 degrees) on the orthogonal propagation plane. Note that the arrows of the phase distribution of OAM mode -1 and -2 signals point in opposite directions.

[0020] The signal intensity distribution and the position where the signal intensity is maximum differ for each OAM mode. However, the intensity distribution is the same for the same OAM mode with different signs. Specifically, the higher the order of the OAM mode, the farther the position where the signal intensity is maximum is from the propagation axis (Non-Patent Document 2). Here, the OAM mode with a larger value is called a higher order mode. For example, a signal of OAM mode 3 is a higher order mode than signals of OAM mode 0, OAM mode 1, and OAM mode 2.

[0021] Figure 2 (3) shows the position where the signal strength is maximum for each OAM mode as a circle. The higher the OAM mode, the farther the position where the signal strength is maximum is from the central axis. Also, the beam diameter of the OAM mode multiplexed signal expands depending on the propagation distance, so the circle showing the position where the signal strength is maximum for each OAM mode becomes larger.

[0022] Also, as shown in Fig. 3, for example, signals of the same OAM mode can be multiplexed and transmitted by a multiple UCA in which multiple UCAs of different diameters are arranged concentrically. On the receiving side, the multiplexed signals in the same OAM mode can be separated by MIMO technology. Fig. 3 shows an example of a multiple UCA in which four UCAs of different diameters are arranged concentrically.

[0023] (Summary of the embodiment of the present invention) As mentioned above, a transmitting device using UCA enables large-capacity communication, but conventional wireless transmission technology using UCA does not support multi-directional communication and has low mobility tracking capabilities.

[0024] Therefore, in this embodiment, an array antenna (called a "lattice point array antenna") is used in which multiple antenna elements are arranged at lattice points on each surface of a polyhedron. The lattice formed by multiple lattice points (lattice formed by lines connecting lattice points) may be any of an oblique lattice, rhombic lattice, central rectangular lattice, isosceles triangular lattice, hexagonal lattice, regular triangular lattice, square lattice, rectangular lattice, parallelepiped lattice, distorted oblique lattice, and other lattices. Note that the "lattice points" on each surface of the polyhedron in this embodiment may be points that are arranged according to some regularity.

[0025] In addition, the polyhedron on which the multiple antenna elements are arranged may be a cube, a rectangular parallelepiped, or a polyhedron other than a cube or a rectangular parallelepiped. In the following, an example in which a cube is used as the polyhedron will be described.

[0026] An example of a lattice point array antenna is shown in Figure 4. As shown in Figure 4, from among the multiple antenna elements that make up the lattice point array antenna, a UCA (multiple antenna elements on a circle) whose transmission axis is aligned with the transmission direction is selected for OAM multiplex transmission. This makes it possible to achieve multi-directional support and movement tracking. Note that transmission in one OAM mode may also be performed. "OAM transmission" includes OAM multiplex transmission.

[0027] (Example of lattice array antenna configuration) The lattice point array antenna in this embodiment has a plurality of antenna elements at lattice points on the surface of a polyhedron. The direction (orientation) of each antenna element is variable. The direction (orientation) of each antenna element may be fixed. In the following, a cube is used as an example of a polyhedron. The following explanation of a "cube" is similarly applicable to polyhedrons other than cubes.

[0028] An example of the configuration of a lattice point array antenna is shown in Fig. 5. The example in Fig. 5 is an example in which antenna elements are arranged at each lattice point (each vertex of a square) that constitutes a square lattice (a lattice in which squares share sides) on each surface of a cube. Specifically, each face that constitutes a cube is divided into thirds vertically and horizontally, and an antenna element is arranged at each vertex of the nine equally divided squares (each of which may be called a unit cell). However, if a vertex is shared by multiple squares, one antenna element is arranged at that vertex (lattice point). However, this is just an example, and multiple antenna elements with different orientations may be provided at one lattice point.

[0029] Each ■ indicates an antenna element. In addition, for multiple antenna elements (antenna elements that make up a UCA) that exist on one circle, the circle is drawn so that it passes through those multiple antenna elements. In the example of Figure 5, three circles (three UCAs) are shown on the xy plane in the foreground of the figure.

[0030] Fig. 6 is a diagram showing an example of the arrangement of antenna elements at the corners of a cube, such as that shown in A of Fig. 5. Since three faces meet at the corners of a cube, in the example of Fig. 6(a), one antenna element is arranged on each of the three faces. In addition, in the example of Fig. 6(b), one antenna element is provided, and the direction (orientation) of the antenna element is variable.

[0031] As an example, assume that each antenna element is a planar antenna element, and that the radiation intensity of the antenna element is greatest in the direction perpendicular to the plane.

[0032] The antenna elements placed at each lattice point on each face of the cube may be fixedly positioned so that the direction of the antenna element (the direction in which the radiation intensity is maximum) faces perpendicular to the face on which they are placed, or the direction of each antenna element may be variable.

[0033] An example of one directional antenna element arranged on the face of a cube is shown in Fig. 7. As shown in Fig. 7, the antenna element can be rotated on each of the x-axis, y-axis, and z-axis, so that the antenna element can be oriented in any direction.

[0034] Furthermore, among the antenna elements constituting the lattice point array antenna, the antenna elements constituting the UCA with the transmission axis aligned with the transmission direction may be selected in any manner. For example, as shown in Fig. 5, the antenna elements constituting the UCA may be selected for each face of a cube.

[0035] In this case, for example, a surface is selected whose vertical direction is closest to the direction from the lattice point array antenna toward the position of the receiving device (transmission axis), and one UCA (multiple antenna elements on a circle) or multiple UCAs with different diameters are selected on that surface to perform OAM multiplex transmission or OAM-MIMO multiplex transmission. In this case, the direction of the antenna elements of each UCA used for transmission may be adjusted so that it is in the direction toward the position of the receiving device (transmission axis).

[0036] Alternatively, a surface obtained by cutting a cube along an arbitrary plane and having a perpendicular direction from the lattice-point array antenna toward the position of the receiving device (transmission axis) may be selected, and one UCA (multiple antenna elements on a circle) or multiple UCAs with different diameters may be selected on that surface to perform OAM multiplex transmission or OAM-MIMO multiplex transmission. In this case, the direction of each antenna element of the UCA used for transmission is adjusted so that it faces the position of the receiving device (transmission axis).

[0037] For example, if the direction perpendicular to the plane that includes the centers of the four lattice points B, C, D, and E in Fig. 5 is the transmission axis, a UCA as shown in Fig. 8 can be configured with four antenna elements on a circle on the surface of a cube cut by said plane. The direction of each antenna element of the UCA is oriented in the direction of the transmission axis (the perpendicular direction to the paper surface of the figure).

[0038] In addition, when constructing a UCA with multiple antenna elements on a circle on a surface obtained by cutting a cube with an arbitrary plane, antenna elements that are somewhat away from the surface (for example, within a certain threshold value) may be considered to be on the surface.

[0039] As described above, when the transmission axis is oriented in any direction, a UCA can be configured by selecting multiple antenna elements arranged in a circle on a plane perpendicular to the transmission axis. In addition, since the direction of the antenna elements is variable, the directivity (the direction in which the radiation intensity is maximized) of each antenna element constituting the UCA can be oriented in the direction of the transmission axis.

[0040] In addition, by selecting multiple antenna elements arranged in a circle on a plane perpendicular to the transmission axis for each of multiple transmission axes, as shown in the image in Figure 4, it is possible to realize OAM multiplexed transmission in multiple directions using multiple UCAs simultaneously.

[0041] In addition, by selecting multiple faces (each face having multiple antenna elements) perpendicular to one transmission axis, or by selecting one face (for example, the surface of a cube), it is possible to select multiple antenna elements arranged on concentric circles with different diameters as shown in Figure 3, making it possible to perform OAM-MIMO multiplexed transmission in any direction.

[0042] In this embodiment, an example in which a plurality of antenna elements are arranged on the surface of a polyhedron is described, but the present invention is not limited to this. For example, antenna elements may also be arranged at lattice points inside the polyhedron. In this case, the arrangement of antenna elements shown in FIG. 3 can be realized depending on the cross section of the polyhedron.

[0043] (Example of transmitter configuration) An example of the configuration of a transmitting device 100 equipped with the above-mentioned lattice point array antenna is shown in Fig. 9. As shown in Fig. 9, the transmitting device 100 includes a lattice point array antenna, a changeover switch unit 30, an OAM mode generating unit 40, an analog signal processing unit 50, a digital signal processing unit 60, and a control unit 110.

[0044] In the example of Fig. 9, it is assumed that there are N selectable UCAs in the lattice point array antenna, which are shown as UCAs 10_1 to 10_N. In Fig. 9, each of UCAs 10_1 to 10_N is shown to be one UCA selected in the lattice point array antenna. The functional overview of each unit is as follows.

[0045] The digital signal processing unit 60 generates, from the input data, a digital signal to be transmitted on a carrier wave, and outputs the generated digital signal to the analog signal processing unit 50. The analog signal processing unit 50 converts the digital signal into an analog signal.

[0046] The OAM mode generation unit 40 generates one or more OAM mode signals from the input analog signal, and outputs the generated signals to the changeover switch unit 30.

[0047] The changeover switch unit 30 transmits the signal generated by the OAM mode generation unit 40 to the selected UCA or UCAs based on an instruction from the control unit 110. This makes it possible to perform one-way OAM multiplex transmission, multiple-way OAM multiplex transmission, one-way OAM-MIMO multiplex transmission, multiple-way OAM-MIMO multiplex transmission, simultaneous OAM multiplex transmission in one direction and OAM-MIMO multiplex transmission in another direction, and the like from the lattice point array antenna.

[0048] In the configuration example of Fig. 9, it is assumed that a Butler circuit or the like that creates an OAM mode signal from an analog signal is used as the OAM mode generation unit 40, but this is just one example. For example, an OAM mode signal may be generated by digital signal processing, and the digital OAM mode signal may be converted to an analog signal and supplied to the UCA. In this case, as shown in Fig. 10, the OAM mode generation unit 40 becomes part of the digital signal processing unit 60, and outputs the analog signal converted by the analog signal processing unit 50 to the changeover switch unit 30.

[0049] The connection by the changeover switch unit 30 may be a physical (mechanical) connection, or may be a method of selecting a specific frequency corresponding to the selected UCA.

[0050] In the case of the method of selecting a frequency, for example, as shown in Fig. 11, the changeover switch unit 30 includes a frequency conversion unit 31 and a plurality of band-limiting filters 32 that pass only frequencies corresponding to each UCA, and each band-limiting filter 32 is connected to a corresponding UCA. The control unit 110 instructs the frequency conversion unit 31 to change the frequency of the OAM mode signal input to the changeover switch unit 30 to a frequency that matches the corresponding UCA. Alternatively, instead of processing by the frequency conversion unit 31, the control unit 110 instructs the analog signal processing unit 50 to change the frequency of the carrier wave to a frequency that matches the UCA.

[0051] 12 shows a configuration example of the changeover switch unit 30 in the case where a plurality of OAM signals are transmitted using different UCAs, such as when an OAM signal in OAM mode 1 is transmitted using UCA_1 and an OAM signal in OAM mode 2 is transmitted using UCA_2. The changeover switch unit 30 shown in Fig. 11 is replaced with the changeover switch unit 30 of configuration pattern A in Fig. 12(a) or the changeover switch unit 30 of configuration pattern B in Fig. 12(b).

[0052] 12(a), there are provided M frequency conversion units 31_1 to 31_M corresponding to UCA groups 1 to M. Each UCA group is made up of one or more UCAs. Each frequency conversion unit 31 is connected to one or more band-limiting filters 32 connected to the UCAs of the corresponding UCA group via branches.

[0053] The signals output from each frequency conversion unit 31 are branched and supplied to each connected band limiting filter 32, and the signal is output from the band limiting filter 32 that can pass the signal. In configuration pattern A of Fig. 12(a), multiplexing is not performed between different frequency conversion units 31.

[0054] In configuration pattern A of Figure 12(a), as an example, when an OAM signal is transmitted using two UCAs, for example, one UCA is selected from UCA group 1 and one UCA is selected from UCA group M.

[0055] 12(b), configuration pattern B includes M frequency conversion units 31_1 to 31_M, and all UCAs are the selection range for each frequency conversion unit 31. Band-limiting filters 32_1 to 32_N are connected to each frequency conversion unit 31 via a branch. A signal output from each frequency conversion unit 31 is branched and supplied to each band-limiting filter 32, and a signal is output from the band-limiting filter 32 that can pass the signal.

[0056] In configuration pattern B of FIG. 12(b), multiplexing is performed between different frequency conversion units 31, but even if multiplexed, the signals will not mix if the frequency bands are different.

[0057] 12(b), as an example, when an OAM signal is transmitted using two UCAs, for example, UCA_1 and UCA_N are selected. In this case, a certain frequency conversion unit 31 outputs a signal to pass through a band-limiting filter 32_1 connected to UCA_1, and another frequency conversion unit 31 outputs a signal to pass through a band-limiting filter 32_N connected to UCA_N.

[0058] It is also possible to adopt a hybrid configuration having both the configuration of configuration pattern A (configuration for only demultiplexing) and the configuration of configuration pattern B (configuration for both demultiplexing and multiplexing).

[0059] 11 and 12 correspond to the configuration in FIG. 9, but even in the case of the configuration in FIG. 10, the configuration of the changeover switch unit 30 in the case of adopting a method for selecting a frequency is similar to the configuration of the changeover switch unit 30 shown in FIGS. 11 and 12.

[0060] An example of the configuration of the OAM mode generation unit 40 when using a Butler circuit is shown in Fig. 13. In the example shown in Fig. 13, there are four Butler circuits 41 to 44. The number of Butler circuits provided in the OAM mode generation unit 40 corresponds to the number of UCAs to be simultaneously selected from the lattice point array antenna. Fig. 13 shows four Butler circuits 41 to 44, but the number of four is just an example.

[0061] For example, when UCA_1, UCA_2, UCA_3, and UCA_4 are selected from the lattice point array antenna to simultaneously perform OAM multiplexing transmission in four directions, Butler circuits 41 to 44 transmit signals in one or more OAM modes to the corresponding UCAs (UCAs connected by changeover switch unit 30). For example, when multiplexing OAM mode 1 and OAM mode 2 in each UCA, a signal in OAM mode 1 and a signal in OAM mode 2 are supplied to each UCA.

[0062] In addition, for example, when four concentric UCAs with different diameters, UCA_1, UCA_2, UCA_3, and UCA_4, are selected from a lattice point array antenna and OAM-MIMO multiplexing transmission is performed, one or more OAM mode signals are supplied from each Butler circuit to the corresponding UCA in the same manner as described above.

[0063] As an example, if a UCA connected to one Butler circuit consists of eight antenna elements and multiplexes OAM mode 1 and OAM mode -1, the Butler circuit has eight output ports, and each output port outputs a signal that is a combination (multiplexed) of signals with a phase difference of 45° (360° / 8) counterclockwise and signals with a phase difference of -45° counterclockwise. The signal from each output port is supplied to the corresponding antenna element.

[0064] Then, each antenna element of the UCA outputs a signal that is a combination of two signals having the following phases:

[0065] Antenna element #1 = (0°, 0°), antenna element #2 = (45°, -45°), antenna element #3 = (90°, -90°), antenna element #4 = (135°, -135°), antenna element #5 = (180°, -180°), antenna element #6 = (225°, -225°), antenna element #7 = (270°, -270°), antenna element #8 = (315°, -315°).

[0066] (Example of operation) An example of the operation of the transmitting device 100 in this embodiment will be described with reference to the flowchart of FIG.

[0067] In S101, data is input to the digital signal processing unit 60. In S102, the digital signal processing unit 60 generates a digital signal to be transmitted on a carrier wave from the input data, and outputs the generated digital signal to the analog signal processing unit 50.

[0068] In S103, the analog signal processing unit 50 converts the digital signal into an analog signal (digital-analog conversion) and converts the frequency of the output signal into the carrier frequency band (e.g., 28 GHz band). The analog signal processing unit 50 inputs the generated analog signal to the OAM mode generation unit 40.

[0069] Here, assuming that OAM mode generation unit 40 is configured using the Butler circuit shown in FIG. 13 and OAM multiplexed transmission of OAM modes 1 and -1 is performed simultaneously using four UCAs, a signal to be transmitted in OAM mode 1 and a signal to be transmitted in OAM mode -1 are input from analog signal processing unit 50 to each Butler circuit in OAM mode generation unit 40.

[0070] In S104, each Butler circuit in the OAM mode generating unit 40 generates an OAM mode signal and outputs the generated signal from each output port. In S105, the changeover switch unit 30 supplies the signal to each antenna element of each UCA used for transmission, and in S106, transmission is performed.

[0071] (Regarding control) As described above, the transmitting device 100 can select a UCA having a transmission axis in any direction from the lattice point array antenna and perform OAM multiplexing transmission in that direction. The control for this purpose is executed by the control unit 110. An example of the control by the control unit 110 will be described below.

[0072] Here, it is assumed that the control unit 110 in the transmitting device 100 is aware of the position of each receiving device (which may be the direction in which the receiving device is located relative to the transmitting device 100). Any method may be used for the control unit 110 of the transmitting device 100 to understand the state of the receiving side (such as the position of the receiving device). For example, the control unit 110 may understand the position of the receiving device by receiving a reference signal transmitted from the receiving device, or may understand the position of the receiving device by receiving position information transmitted from the receiving device. Furthermore, the position of the receiving device (such as a fixed position, a planned position to which the receiving device is moved at each time, etc.) may be preset in the control unit 110.

[0073] For example, when the control unit 110 determines that a receiving device to which a signal is to be transmitted is located at position A shown in FIG. 15, the control unit 110 selects a UCA_X consisting of multiple antenna elements on a plane perpendicular to the direction (transmission axis) from the transmitting device 100 (lattice point array antenna) to position A, and instructs the changeover switch unit 30 to connect the selected UCA_X to the OAM mode generation unit 40, and the changeover switch unit 30 connects them in accordance with the instruction.

[0074] Furthermore, the control unit 110 instructs the lattice point array antenna to orient the direction of each antenna element in the selected UCA_X in the transmission direction (transmission axis direction), and the lattice point array antenna orients the direction of each antenna element in UCA_X in the transmission direction.

[0075] In addition, when it is possible to select multiple UCAs each consisting of multiple antenna elements on a plane perpendicular to the transmission axis, any or all of the multiple UCAs may be selected to perform OAM-MIMO multiplexing transmission.

[0076] In addition, when multiple UCAs consisting of multiple antenna elements on a plane perpendicular to the transmission axis can be selected, a signal may be transmitted from each UCA, and the UCA with the best reception quality may be selected and used based on feedback from the receiving device.

[0077] As shown in Fig. 16, even when a receiving device is located at a position B different from position A, UCA_Y suitable for position B is selected and transmission is performed in the same manner as in the case of Fig. 15. Transmission may also be performed using UCA_X and UCA_Y simultaneously.

[0078] 15 moves, the control unit 110 tracks the movement of the receiving device. That is, as described above, it is assumed that the control unit 110 always knows the position of the receiving device.

[0079] For example, when the angle between the transmission axis of UCA_X selected before the movement and the transmission axis after the movement becomes equal to or larger than a certain threshold, the control unit 110 switches the UCA for communication with the receiving device from UCA_X to another UCA. That is, if the position of the receiving device after the movement is position A', the control unit 110 selects UCA_X' consisting of multiple antenna elements on a plane perpendicular to the direction (transmission axis) from the transmitting device 100 (lattice point array antenna) to position A', and switches the UCA for communication with the receiving device from UCA_X to UCA_X'.

[0080] (Effects of the embodiment) The technology according to the present embodiment described above enables a transmitting device using UCA to support multiple directions and follow movement. In addition, OAM or OAM-MIMO multiplex transmission is possible by aligning axes in any multiple directions. Furthermore, it is possible to change the transmission axis by switching UCA and follow movement.

[0081] (Summary of the embodiment) This specification describes at least the transmission device and transmission method described in the following items. (Section 1) a lattice point array antenna having a plurality of antenna elements on a polyhedron; a control unit that selects a plurality of antenna elements present on an arbitrary circle from the plurality of antenna elements in the lattice point array antenna as a UCA and performs OAM transmission using the selected UCA; A transmitting device comprising: (Section 2) The control unit selects a plurality of UCAs from the plurality of antenna elements in the lattice point array antenna, and causes the selected plurality of UCAs to perform OAM transmission in a plurality of directions. A transmitting device as described in item 1. (Section 3) The control unit selects a plurality of UCAs having different diameters from the plurality of antenna elements in the lattice point array antenna, and performs OAM-MIMO transmission using the selected plurality of UCAs. A transmitting device as described in claim 1 or 2. (Section 4) The control unit switches the UCA in response to movement of the receiving device. A transmitting device according to any one of claims 1 to 3. (Section 5) The control unit orients each antenna element constituting the selected UCA in a transmission direction. A transmitting device according to any one of claims 1 to 4. (Section 6) A transmission method implemented by a transmitting device having a lattice point array antenna with a plurality of antenna elements on a polyhedron, comprising the steps of: A plurality of antenna elements present on an arbitrary circle are selected as UCAs from the plurality of antenna elements in the lattice point array antenna, and OAM transmission is performed using the selected UCAs. Transmission method.

[0082] Although the present embodiment has been described above, the present invention is not limited to such a specific embodiment, and various modifications and variations are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0083] 10 UCA 30 Changeover switch section 31 Frequency conversion section 32 Bandwidth Limiting Filter 40 OAM mode generation unit 50 Analog signal processing section 60 Digital Signal Processing Unit 100 Transmitting device 110 Control section

Claims

1. a lattice point array antenna having a plurality of antenna elements on a polyhedron; a control unit that selects a plurality of antenna elements present on an arbitrary circle from the plurality of antenna elements in the lattice point array antenna as a UCA and causes OAM transmission to be performed by the selected UCA, The control unit orients each antenna element constituting the selected UCA in a transmission direction. Transmitting device.

2. The control unit selects a plurality of UCAs from the plurality of antenna elements in the lattice point array antenna, and causes the selected plurality of UCAs to perform OAM transmission in a plurality of directions. The transmitting device according to claim 1 .

3. The control unit selects a plurality of UCAs having different diameters from the plurality of antenna elements in the lattice point array antenna, and causes OAM-MIMO transmission to be performed by the selected plurality of UCAs.

3. A transmitting device according to claim 1 or 2.

4. The control unit switches the UCA in response to movement of the receiving device.

4. A transmitting device according to claim 1, wherein the transmitting device is a digital signal processing device.

5. A transmission method implemented by a transmitting device having a lattice point array antenna with a plurality of antenna elements on a polyhedron, comprising the steps of: a transmission method for selecting a plurality of antenna elements present on an arbitrary circle from the plurality of antenna elements in the lattice point array antenna as a UCA, and performing OAM transmission using the selected UCA, The transmitting device orients each antenna element constituting the selected UCA in a transmitting direction. Transmission method.

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