Transmitting device and transmitting method

Abstract

This transmission device comprises: a signal generation unit that generates a radio signal having a designated beam direction angle; and an airy beam generation unit that generates an airy beam by changing the phase of the radio signal.

Description

[Technical Field]

[0001] The present invention relates to a transmitting device and a transmitting method. [Background technology]

[0002] Normally, electromagnetic waves have the property of spreading and propagating linearly in the direction of propagation. However, by applying amplitude-phase conversion to a radio signal incident on a two-dimensional plane, it is possible to generate an Airy beam, which has the property of bending the trajectory of the main lobe in the direction of propagation.

[0003] Airy beams have the property of forming communication areas with extremely low received power, but the trajectory of the main lobe of an Airy beam is limited, and the beam direction cannot be controlled. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] D. Zhang, B. Chen, Z. Ba, S. Ni, J. Cao, and X. Wang, “Generation of Broadband THz Airy Beams Applying 3D Printing Technique”, 13th European Conference on Antennas and Propagation (EuCAP 2019) [Non-patent document 2] NK Efremidis, Z. Chen, M. Segev, and DN Christodoulides, “Airy beams and accelerating waves: an overview of recent advances“, Optica, vol.6, pp.686-701 (2019) Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a transmitting device and a transmitting method that can control the beam direction of an Airy beam. [Means for solving the problem]

[0006] One aspect of the present invention is a transmitting device comprising a signal generating unit that generates a radio signal having a specified beam direction angle, and an Airy beam generating unit that generates an Airy beam by changing the phase of the radio signal.

[0007] One aspect of the present invention is a transmission method that generates a radio signal having a specified beam direction angle and generates an Airy beam by changing the phase of the radio signal. [Effects of the Invention]

[0008] The transmitting device and transmitting method of the present invention can control the beam direction of an Airy beam. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an example of a configuration of a transmission device 100 according to a first embodiment. [Figure 2] FIG. 1 shows a transmitting antenna 130 and the beam emitted. [Figure 3] 1 shows an example of the configuration of an Airy beam generating unit 140. [Figure 4] 10 is another example of the configuration of the Airy beam generating unit 140. [Figure 5] 1 is an example of a cross-sectional view of an xz plane of a generated Airy beam when the Airy beam generating unit 140 is placed on the xy plane. [Figure 6] 1 is an example showing Airy beams generated by two transmitting devices 100-1 and 100-2. [Figure 7] FIG. 10 is a diagram illustrating an example of a configuration of a transmission device 100 according to a second embodiment. [Figure 8] FIG. 1 is a front view of a planar Airy beam generating unit 140. [Figure 9] 10 is a diagram showing the intensity distribution of the Airy beam transmitted from the Airy beam generating unit 140 (the intensity distribution on the opposing surface of the Airy beam generating unit 140). FIG. [Figure 10] FIG. 10 is a front view of a planar Airy beam generating unit 140 when the spatial multiplexing level is 8. [Figure 11] 10 is a diagram showing the intensity distribution of the Airy beam transmitted from the Airy beam generating unit 140 (the intensity distribution on the opposing surface of the Airy beam generating unit 140). FIG. [Figure 12] FIG. 10 illustrates adjusting the size of the antenna. [Figure 13] FIG. 10 illustrates adjusting the size of the antenna. DETAILED DESCRIPTION OF THE INVENTION

[0010] (First embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 shows an example of the configuration of a transmission device 100 according to the first embodiment. As shown in Fig. 1, the transmission device 100 according to the first embodiment includes a beam direction angle specifying unit 110, a signal generating unit 120, a transmitting antenna 130, and an Airy beam generating unit 140.

[0011] The beam direction angle designation unit 110 designates the direction angle θ of the beam emitted from the transmitting antenna 130 .

[0012] The signal generation unit 120 generates, from the input data, a digital signal to be transmitted on a carrier wave. The signal generation unit 120 converts the digital signal into an analog signal, converts the frequency of the analog signal into the frequency band of the carrier wave, and outputs the analog signal to the transmitting antenna 130. The signal generation unit 120 generates a radio signal based on the direction angle specified by the beam direction angle specification unit 110. The method of generating the radio signal will be described later. The transmitting antenna 130 radiates the analog signal generated by the signal generation unit 120.

[0013] Fig. 2 is a diagram showing a transmitting antenna 130 and a beam emitted. The transmitting antenna 130 is made up of multiple adjacent antennas 131. In the example shown in Fig. 2, the transmitting antenna 130 is made up of four adjacent antennas 131-1, 131-2, 131-3, and 131-4. If the distance between adjacent antennas 131 is d, the angle of the beam emitted from the transmitting antenna 130 with respect to the z direction is θ, the wavelength of the radio signal supplied to antenna 131 is λ, and the phase difference of the analog signals supplied to adjacent antennas 131 is Δφ, then these have the relationship shown in Equation (1).

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[0014] When d and λ are constants, θ can be changed by changing Δφ. That is, the signal generator 120 calculates the phase difference Δφ of the radio signals based on the beam direction angle θ specified by the beam direction angle specify unit 110 and equation (1), and supplies analog signals to the antennas 131 of the transmitting antenna 130 so that the phase difference of the analog signals supplied to the adjacent antennas 131 becomes the calculated Δφ.

[0015] The Airy beam generator 140 generates an Airy beam by changing the phase of the beam emitted from the transmitting antenna 130. The Airy beam generator 140 generates an Airy beam, for example, by imparting a phase to the beam using multiple antenna elements. FIG. 3 shows an example of the configuration of the Airy beam generator 140. FIG. 3 is a front view of the planar Airy beam generator 140. The Airy beam generator 140 shown in FIG. 3 is a metasurface (metamaterial) antenna having multiple antenna elements (patch antennas) on a planar substrate. For example, each antenna element is equipped with a variable phase shifter, which can impart a predetermined phase to the electromagnetic wave (radio wave) for each antenna element. The degree of curvature of the Airy beam changes depending on the phase imparted to each antenna element.

[0016] The Airy beam generator 140 may generate an Airy beam by changing the phase of the beam radiated from the transmitting antenna 130 by changing the thickness of the dielectric material through which the beam passes across the plane. FIG. 4 shows another configuration example of the Airy beam generator 140. In this configuration example, the Airy beam generator 140 has, for example, a circular shape when viewed from the front. FIG. 4 shows a cross-sectional view of the Airy beam generator 140 taken along a plane including the axis of the radio wave transmission direction of the transmitting antenna 130. In the example shown in FIG. 4, the Airy beam generator 140 includes a phase modulation lens 143 and a Fourier transform lens 144. If the plane viewed from the front of the transmitting antenna 130 is defined as an xy plane, the phase modulation lens 143 imparts a phase to each point (xy coordinate) on the xy plane, thereby generating an Airy beam.

[0017] Specifically, the Airy beam generating unit 140 generates an Airy beam by imparting the amplitude and phase u(x, y) shown in equation (2) to a beam on the xy plane. In equation (2), a is an arbitrary constant that determines the degree of curvature of the Airy beam.

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[0018] FIG. 5 shows an example of a cross-sectional view of the xz plane of the generated Airy beam when the Airy beam generating unit 140 is placed on the xy plane. FIG. 5A shows the case where the beam angle θ is 0 degrees, and FIG. 5B shows the case where the beam angle θ is 45 degrees. In the example shown in FIG. 5A, the Airy beam bends upward, with side lobes occurring at the bottom of the beam and no side lobes occurring at the top of the beam. In the example shown in FIG. 5B, the Airy beam bends upward, with side lobes occurring at the bottom of the beam and no side lobes occurring at the top of the beam. FIGS. 5A and 5B show that the direction of the Airy beam changes depending on the beam angle.

[0019] FIG. 6 shows an example of Airy beams generated by two transmitting devices 100-1 and 100-2. Transmitting device 100-1 and transmitting device 100-2 transmit beams with angles of opposite positive and negative. At this time, a side lobe is generated at the bottom of the Airy beam transmitted from transmitting device 100-1, but no side lobe is generated at the top. A side lobe is generated at the top of the Airy beam transmitted from transmitting device 100-2, but no side lobe is generated at the bottom. Therefore, transmitting device 100-1 and transmitting device 100-2 can form an area where no side lobes are generated.

[0020] (Second embodiment) 7 is a diagram showing an example of the configuration of a transmitting device 100 according to the second embodiment. In the second embodiment, data transmitted by the transmitting device 100 is received by the receiving device 200. Hereinafter, the transmitting device 100 and the receiving device 200 will be collectively referred to as a wireless communication system 10. Receiving device 200 includes a receiving unit 210, a receiving intensity measuring unit 220, and a feedback unit 230. Receiving unit 210 receives an analog signal transmitted from transmitting device 100 via an antenna. Receiving unit 210 may receive the signal using a configuration similar to that of Airy beam generating unit 140 included in transmitting device 100, or may be a general antenna that does not include a special configuration for an Airy beam.

[0021] The reception strength measurement unit 220 measures the reception strength of a received signal. The feedback unit 230 feeds back the measurement result of the reception strength to the transmitting device 100. The feedback unit 230 may perform the feedback by sending a signal to the transmitting device 100 using normal wireless communication. In the second embodiment, the beam direction angle designation unit 110 of the transmitting device 100 designates the beam direction angle θ based on the feedback from the receiving device 200. For example, the transmitting device 100 changes the angle of the beam radiated from the transmitting antenna 130 according to a predetermined schedule and transmits multiple Airy beams as preambles to the receiving device 200. In the receiving device 200, the reception intensity measurement unit 220 measures the reception intensity of each Airy beam, and the feedback unit 230 feeds back to the transmitting device 100 the timing, time, or order in which the Airy beam with the highest reception intensity was received. The beam direction angle designation unit 110 designates the beam direction angle θ corresponding to the fed-back timing, time, or order as the angle of the beam radiated from the transmitting antenna 130.

[0022] The transmitting device 100 may include information about the beam direction angle θ in a preamble transmitted to the receiving device 200. At this time, the receiving device 200 measures the reception strength and reads out the information about the beam direction angle θ. The feedback unit 230 feeds back to the transmitting device 100 the beam direction angle θ indicated by the information included in the Airy beam with the maximum reception strength. The beam direction angle designation unit 110 designates the fed-back beam direction angle θ as the angle of the beam to be radiated from the transmitting antenna 130. When the preamble transmitted by the transmitting device 100 includes information about the beam direction angle θ, the transmitting device does not need to change the beam direction angle θ according to a predetermined schedule to transmit the Airy beam.

[0023] The feedback unit 230 may feed back the correspondence between the reception strength of the Airy Beam and the timing, time, order, or beam direction angle θ at which the Airy Beam was received to the transmitting device 100. In this case, the transmitting device 100 determines the timing, time, order, or beam direction angle θ corresponding to the maximum reception strength based on the correspondence between the reception strength of the Airy Beam that has been fed back and the timing, time, order, or beam direction angle θ at which the Airy Beam was received, and specifies the beam direction angle θ.

[0024] The transmitting device 100 may specify the beam direction angle θ based on the reception strength of the Airy beam, which differs depending on multiple predetermined positions of the receiving device 200. The transmitting device 100 acquires information on the beam direction angle θ and the reception strength of the Airy beam for each position of the receiving device 200, and determines a beam direction angle θ at which the reception strength is equal to or greater than a predetermined threshold when the receiving device 200 is located at one of the multiple positions, but at which the reception strength is equal to or less than the predetermined threshold when the receiving device 200 is located at all positions other than the one position among the multiple positions, and specifies this as the angle of the beam to be radiated from the transmitting antenna 130. In other words, when the receiving devices 200 are installed at all of the multiple predetermined positions, the transmitting device 100 can deliver an Airy beam with a reception strength equal to or greater than the predetermined threshold to only one receiving device 200 when radiating a beam at the determined beam direction angle θ.

[0025] Furthermore, the transmitting device 100 may acquire the distance between the antennas of the transmitting device 100 and the receiving device 200. Any method for acquiring the distance may be used. For example, the distance may be acquired from an external server, or the positions of the transmitting antenna 130 or the Airy beam generating unit 140 and the antenna of the receiving unit 210 may be acquired using a GPS function, and the distance may be calculated from the positions, or the distance may be calculated using a signal delay time. The transmitting device 100 may determine the beam direction angle θ based on the distance between the antennas of the transmitting device 100 and the receiving device 200 .

[0026] The transmitting device 100 may be equipped with a plurality of transmitting antennas 130 and Airy beam generating units 140 as sub-transmitting antennas and sub-Airy beam generating units, and may perform spatial multiplexing communications. Fig. 8 is a front view of the planar Airy beam generating unit 140. The Airy beam generating unit 140 shown in Fig. 8 is equipped with sub-Airy beam generating units #1 to #4, each of which has a plurality of antenna elements as shown, and is capable of generating an Airy beam.

[0027] The receiver 200 also has four different antennas to achieve spatial multiplexing communication, but does not necessarily have a sub-Airly beamformer. The sub-transmitting antennas #1 and #3 face the sub-receiving antennas #3 and #1, and the sub-transmitting antennas #2 and #4 face the sub-receiving antennas #4 and #2.

[0028] Fig. 9 is a diagram showing the intensity distribution of the Airy beam transmitted from the Airy beam generating unit 140 (the intensity distribution on the opposing surface of the Airy beam generating unit 140). As shown in Fig. 9, the side lobes of each sub-Airy beam generating unit are generated on the side opposite to the side where other sub-sub Airy beam generating units are present. This enables spatial multiplexing transmission with a spatial multiplexing number of 4 to be performed without interference between the sub-sub Airy beam generating units.

[0029] Next, a case where the transmitting antenna 130 and the Airy beam forming unit 140 each have eight sub-transmitting antennas and eight sub-Airy beam forming units, that is, a case where the spatial multiplexing number is eight, will be described. FIG. 10 is a front view of the planar Airy beam generator 140 when the spatial multiplexing level is 8. The receiving device 200 also has eight different antennas to achieve spatial multiplexing communication, but does not necessarily have to have sub-Airy beam generators. As shown in FIG. 10, the Airy beam generator 140 has sub-Airy beam generators #1 to #8, each of which has multiple antenna elements as shown and is capable of generating an Airy beam. The sub-transmitting antennas #1, #8, and #7 face the sub-receiving antennas #7, #8, and #1, the sub-transmitting antennas #2 and #6 face the sub-receiving antennas #6 and #2, and the sub-transmitting antennas #3, #4, and #5 face the sub-receiving antennas #5, #4, and #3.

[0030] Fig. 11 is a diagram showing the intensity distribution of the Airy beam transmitted from the Airy beam generating unit 140 (the intensity distribution on the opposing surface of the Airy beam generating unit 140). As shown in Fig. 11, the side lobes of each sub-antenna appear on the outer side of the center of the eight sub-Airy beam generating units.

[0031] In this case, for example, no interference occurs between the side lobe of sub-Airy beam generating unit #1 and the side lobes of sub-Airy beam generating units #3 to #7, but interference may occur between the side lobe of sub-Airy beam generating unit #1 and the side lobes of sub-Airy beam generating units #2 and #8.

[0032] As described above, the above example is an example in which partial interference is tolerated. That is, in the above example, the transmitting device 100 transmits radio waves so as to allow partial overlap of side lobes. For the overlapping side lobes, the receiving device 200 performs interference cancellation using a method such as SIC (successive interference cancellation). This makes it possible to increase the number of spatial multiplexing signals while maintaining a lower amount of calculation than full MIMO equalization processing.

[0033] The degree of curvature of the Airy beam is adjusted by adaptively adjusting the size of the antennas composed of multiple antenna elements in the sub-Airy beam generators that make up the Airy beam generator 140. This makes it possible to adjust the reach distance or position of the Airy beam. Such size adjustment can be performed by the transmitter 100, for example.

[0034] An example will be described with reference to Figures 12 and 13. As shown in Figure 12, in one sub-Airy beam generating unit, an area indicated by A and an area indicated by B are shown. The size of the area indicated by A is larger than the size of the area indicated by B. In other words, the number of antenna elements included in the area indicated by A is greater than the number of antenna elements included in the area indicated by B.

[0035] Fig. 13 shows an oblique view of the Airy beam generating unit 140 shown in Fig. 12. As shown in Fig. 14, when multiple antenna elements in area A are selected, the degree of bending of the Airy beam is greater than when multiple antenna elements in area B are selected. When multiple antenna elements in area B are selected, the main lobe can be delivered to a receiving device that is located farther away.

[0036] In other words, in the Airy beam generating unit 140, by adjusting the areas of the multiple antenna elements used to generate the Airy beam, the distance the Airy beam reaches can be adjusted so that the radio waves reach the desired position of the receiving device 200. [Explanation of symbols]

[0037] 10 wireless communication system, 100 transmitting device, 110 beam direction angle designation unit, 120 signal generation unit, 130 transmitting antenna, 131 antenna, 140 Airy beam generation unit, 142 plane wave generating lens, 143 phase modulation lens, 144 Fourier transform lens, 200 receiving device, 210 receiving unit, 220 reception intensity measurement unit, 230 feedback unit

Claims

1. a transmitting antenna for transmitting a radio signal having a specified beam direction angle; an Airy beam generating unit that generates an Airy beam by changing the phase of the radio signal; Equipped with The beam direction angle is specified based on the reception intensity of the Airy beam at the receiving side. Transmitting device.

2. A transmitting antenna for transmitting a radio signal having a specified beam direction angle; an Airy beam generating unit that generates an Airy beam by changing the phase of the radio signal; Equipped with the Airy beam generating unit includes a plurality of sub-Airy beam generating units each generating an Airy beam, and performs spatial multiplexing with a spatial multiplexing number of 4 or more. Transmitting device.

3. Transmits a radio signal with a specified beam direction angle, A transmission method for generating an Airy beam by changing the phase of the radio signal, The beam direction angle is specified based on the reception intensity of the Airy beam at the receiving side. Sending method.

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