Transmitting device and transmitting method

Abstract

Provided is a transmission device comprising: a spherical array antenna provided with a plurality of antenna elements on a spherical surface; and a control unit for selecting, as a uniform circular array (UCA), a plurality of antenna elements that are present on a discretionary circle from among the plurality of antenna elements of the spherical array antenna and causing OAM transmission to be carried out by the selected UCA.

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 spherical array antenna having a plurality of antenna elements on a spherical surface, a control unit that selects a plurality of antenna elements present on an arbitrary circle from the plurality of antenna elements in the spherical array antenna as a UCA and performs OAM transmission using the selected UCA; Each antenna element constituting the selected UCA can be rotated on each of the x-axis, y-axis, and z-axis, and the control unit orients each antenna element in the 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 spherical array antenna according to an embodiment of the present invention; [Figure 6] 1 is a diagram showing an example of a spherical array antenna according to an embodiment of the present invention; [Figure 7] 1 is a diagram showing an example of a spherical array antenna according to an embodiment of the present invention; [Figure 8] 1 is a diagram showing an example of a spherical array antenna according to an embodiment of the present invention; [Figure 9] FIG. 2 is a diagram for explaining an antenna element. [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]FIG. 2 is a diagram illustrating a configuration example of a transmitting device according to an embodiment of the present invention. [Figure 13] 2 is a diagram illustrating an example of the configuration of a changeover switch unit 30. FIG. [Figure 14] 2 is a diagram illustrating an example of the configuration of an OAM mode generation unit 40. FIG. [Figure 15] 4 is a flowchart showing a flow of signal processing. [Figure 16] FIG. 13 is a diagram showing an example of transmission by a selected UCA. [Figure 17] 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, a spherical array antenna in which multiple antenna elements are arranged on a spherical surface is used, and as shown in Fig. 4, a UCA with its transmission axis aligned with the transmission direction is selected from among the antenna elements constituting the spherical array to perform OAM multiplex transmission. This makes it possible to achieve multi-directional support and movement tracking. Note that the spheres constituting the "spherical surface" do not have to be exact spheres. Spheres with shapes that are somewhat distorted from a sphere are also acceptable. Also, transmission in one OAM mode may be performed. "OAM transmission" includes OAM multiplex transmission.

[0025] (Example of spherical array antenna configuration) The spherical array antenna in this embodiment has a plurality of antenna elements on the surface of a sphere, and the direction (orientation) of each antenna element is variable.

[0026] An example of the configuration of a spherical array antenna is shown in Figure 5. Figure 5 shows an image of the spherical array antenna as viewed from the direction of the transmission axis indicated by A. In Figure 5, the transmission axis indicated by A is oriented perpendicular to the plane of the paper on which the figure is being viewed, but for convenience of illustration, it is shown as if it is tilted.

[0027] Each square indicates an antenna element. In addition, for multiple antenna elements that exist on a circle, the circle is drawn so that it passes through those multiple antenna elements. Figure 6 shows an image of the spherical array antenna in Figure 5 viewed from an oblique angle.

[0028] Fig. 7 shows an example of a cross-sectional view of the spherical array antenna shown in Fig. 5 cut along a plane including the transmission axis A (a plane including the antenna elements). Fig. 7 shows an example in which each antenna element is a planar antenna element. Therefore, the cross section is linear. It is also assumed that the radiation intensity of the antenna element is maximum in the direction perpendicular to the plane.

[0029] As shown in the cross-sectional view of Figure 7, antenna elements are arranged on a circle in the cross section of a sphere. The direction of each antenna element (the direction with the maximum radiation strength) is oriented along the transmission axis. Note that in the example of Figure 7, all antenna elements are oriented along the transmission axis, but it is sufficient that only the antenna elements that make up the UCA used for transmission are oriented along the transmission axis.

[0030] Fig. 8 shows a cross-sectional view of the spherical array antenna shown in Fig. 5 cut along a plane (including the antenna elements) perpendicular to the transmission axis A. As shown in Fig. 8, one UCA is configured.

[0031] When the transmission axis A is oriented in an arbitrary direction, a UCA such as that shown in Fig. 8 can be configured by selecting multiple antenna elements arranged in a circle on a plane perpendicular to the transmission axis A. 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 that configures the UCA can be oriented in the direction of the transmission axis.

[0032] 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.

[0033] In addition, by selecting multiple planes perpendicular to one transmission axis, 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.

[0034] In this embodiment, an example in which multiple antenna elements are arranged on a spherical surface is described, but the present invention is not limited to this. For example, antenna elements may be arranged inside the sphere. In this case, the cross section of the sphere has the antenna elements arranged as shown in FIG. 3, for example.

[0035] An example of one antenna element arranged on a sphere is shown in Fig. 9. As shown in Fig. 9, 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.

[0036] (Example of transmitter configuration) An example of the configuration of a transmitting device 100 equipped with the above-mentioned spherical array antenna is shown in Fig. 10. As shown in Fig. 10, transmitting device 100 has a spherical 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.

[0037] In the example of Fig. 10, it is assumed that there are N selectable UCAs in the spherical array antenna, which are shown as UCAs 10_1 to 10_N. In Fig. 10, each of UCAs 10_1 to 10_N is shown to be one UCA selected in the spherical array antenna. The functional overview of each unit is as follows.

[0038] 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.

[0039] 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.

[0040] 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, multi-way OAM multiplex transmission, one-way OAM-MIMO multiplex transmission, multi-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 spherical array antenna.

[0041] 10, 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. 11, 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.

[0042] 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.

[0043] In the case of the method of selecting a frequency, for example, as shown in Fig. 12, 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.

[0044] 13 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. 12 is replaced with the changeover switch unit 30 of configuration pattern A in FIG. 13(a) or the changeover switch unit 30 of configuration pattern B in FIG. 13(b).

[0045] 13(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.

[0046] 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. 13(a), multiplexing is not performed between different frequency conversion units 31.

[0047] In configuration pattern A of Figure 13(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.

[0048] 13(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 the signal is output from the band-limiting filter 32 that can pass the signal.

[0049] In configuration pattern B of FIG. 13(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.

[0050] 13(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.

[0051] 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).

[0052] 12 and 13 correspond to the configuration in FIG. 10, but even in the case of the configuration in FIG. 11, the configuration of the changeover switch unit 30 in the case of adopting the method of selecting a frequency is similar to the configuration of the changeover switch unit 30 shown in FIGS. 12 and 13.

[0053] An example of the configuration of the OAM mode generation unit 40 when using a Butler circuit is shown in Fig. 14. In the example shown in Fig. 14, 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 spherical array antenna. Fig. 14 shows four Butler circuits 41 to 44, but the number of four is just an example.

[0054] For example, when UCA_1, UCA_2, UCA_3, and UCA_4 are selected from the spherical 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.

[0055] In addition, for example, when four concentric UCAs with different diameters, UCA_1, UCA_2, UCA_3, and UCA_4, are selected from a spherical 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.

[0056] 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.

[0057] Then, each antenna element of the UCA outputs a signal that is a combination of two signals having the following phases:

[0058] 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°).

[0059] (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.

[0060] 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.

[0061] 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.

[0062] Here, assuming that OAM mode generation unit 40 is configured using the Butler circuit shown in FIG. 14 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.

[0063] 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.

[0064] (Regarding control) As described above, the transmitting device 100 can select a UCA having a transmission axis in any direction from the spherical 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.

[0065] 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.

[0066] 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. 16, 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 (spherical 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.

[0067] Furthermore, control unit 110 instructs the spherical array antenna to orient each antenna element in the selected UCA_X in the transmission direction (transmission axis direction), and the spherical array antenna orients each antenna element in UCA_X in the transmission direction.

[0068] 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.

[0069] 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.

[0070] As shown in Fig. 17, 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. 16. Transmission may also be performed using UCA_X and UCA_Y simultaneously.

[0071] 16 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.

[0072] 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 (spherical array antenna) to position A', and switches the UCA for communication with the receiving device from UCA_X to UCA_X'.

[0073] (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.

[0074] (Summary of the embodiment) This specification describes at least the transmission device and transmission method described in the following items. (Section 1) a spherical array antenna having a plurality of antenna elements on a spherical surface; a control unit that selects a plurality of antenna elements present on an arbitrary circle from the plurality of antenna elements in the spherical array antenna as UCAs and performs OAM transmission using the selected UCAs; A transmitting device comprising: (Section 2) The control unit selects a plurality of UCAs from the plurality of antenna elements in the spherical 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 spherical 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 performed by a transmitting device having a spherical array antenna with a plurality of antenna elements on a spherical surface, comprising: A plurality of antenna elements present on an arbitrary circle are selected as UCAs from the plurality of antenna elements in the spherical array antenna, and OAM transmission is performed by the selected UCAs. Transmission method.

[0075] 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]

[0076] 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 spherical array antenna having a plurality of antenna elements on a spherical surface; a control unit that selects a plurality of antenna elements present on an arbitrary circle from the plurality of antenna elements in the spherical array antenna as a UCA and causes OAM transmission to be performed by the selected UCA, Each antenna element constituting the selected UCA can be rotated on each of the x-axis, y-axis, and z-axis, and the control unit orients each antenna element in the transmission direction. Transmitting device.

2. The control unit selects a plurality of UCAs from the plurality of antenna elements in the spherical 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 spherical array antenna, and causes OAM-MIMO transmission to be performed by the selected plurality of UCAs. The transmitting device according to claim 1 .

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 performed by a transmitting device having a spherical array antenna with a plurality of antenna elements on a spherical surface, comprising: a transmission method for selecting a plurality of antenna elements present on an arbitrary circle from the plurality of antenna elements in the spherical array antenna as a UCA, and performing OAM transmission using the selected UCA, Each antenna element constituting the selected UCA can be rotated on each of the x-axis, y-axis, and z-axis, and the transmitting device orients each antenna element in the transmission direction. Transmission method.

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