Transmitting device and transmitting method

Abstract

A transmission device according to the present invention comprises: a transmission antenna that transmits an airy beam; a distance acquisition unit that acquires the distance between the transmission antenna and a reception antenna that receives the airy beam; and a control unit that, in accordance with said distance, adjusts the angle of the transmission antenna or the initial phase applied to electric waves transmitted from the transmission antenna.

Description

[Technical field]

[0001] The present invention relates to a wireless communication technology using Airy Beams. [Background technology]

[0002] Normally, electromagnetic waves have the property of spreading and propagating linearly in the direction of propagation. However, there exists an Airy beam, which has the property of bending its trajectory in one direction by giving an antenna a special initial phase distribution (for example, Non-Patent Document 1).

[0003] Moreover, in recent years, there has been progress in the study of spatial multiplexing transmission technology for wireless signals using Orbital Angular Momentum (OAM), which is expected to improve transmission capacity in communications in which the transmitting antenna and the receiving antenna are installed facing each other directly.

[0004] By using Airy Beam, it is expected that high-capacity communication can be performed even when the transmitting antenna and receiving antenna are not directly facing each other, but in the prior art, specific technical aspects of wireless communication using Airy Beam have not been sufficiently considered. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] R. Kadlimatti and PV Parimi, "Millimeter-Wave Nondiffracting Circular Airy OAM Beams," in IEEE Transactions on Antennas and Propagation, vol. 67, no. 1, pp. 260-269, Jan. 2019, doi: 10.1109 / TAP.2018.2876713. Summary of the Invention [Problem to be solved by the invention]

[0006] When wireless communication is performed using the above-mentioned Airy beam, the trajectory of the radio waves transmitted from the transmitting antenna curves, and depending on the distance between the transmitting antenna and the receiving antenna, the Airy beam radio waves (especially the main lobe) may not reach the receiving antenna.

[0007] The present invention has been made in consideration of the above points, and aims to provide a technology that enables a receiving antenna to properly receive an Airy beam transmitted from a transmitting antenna when wireless communication is performed using an Airy beam. [Means for solving the problem]

[0008] According to the disclosed technology, there is provided a transmitting antenna for transmitting an Airy beam; a distance acquisition unit that acquires a distance between the transmitting antenna and a receiving antenna that receives the Airy beam; The angle of the transmitting antenna is adjusted according to the distance. and a control unit for adjusting an initial phase to be applied to a radio wave transmitted from the transmitting antenna; , The control unit adjusts the angle using the size of the transmitting antenna and the distance. A transmitting device is provided. Effect of the Invention

[0009] According to the disclosed technology, when wireless communication is performed using Airy beams, the receiving antenna can properly receive the Airy beams transmitted from the transmitting antenna. [Brief description of the drawings]

[0010] [Figure 1] 1 is a system configuration diagram according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a diagram showing the intensity distribution of radio waves regarding an Airy beam. [Diagram 3] FIG. 1 is a diagram showing an image of a cross section of an Airy beam. [Figure 4] FIG. 2 is a diagram illustrating an example of the configuration of a transmitting antenna 110. [Diagram 5] FIG. 2 is a diagram illustrating an example of the configuration of a transmitting antenna 110. [Figure 6] FIG. 1 is a diagram for explaining a technique for reducing interference. [Figure 7] FIG. 1 is a diagram for explaining a technique for reducing interference. [Figure 8] FIG. 1 is a diagram for explaining Example 1-1. [Figure 9] FIG. 13 is a diagram for explaining Example 1-2. [Figure 10] FIG. 13 is a diagram for explaining Example 1-2. [Figure 11] FIG. 13 is a diagram for explaining Example 1-3. [Figure 12] FIG. 13 is a diagram for explaining Example 1-3. [Figure 13] FIG. 13 is a diagram for explaining Example 1-4. [Figure 14] FIG. 13 is a diagram for explaining Example 1-4. [Figure 15] FIG. 2 is a diagram for explaining Example 2-1. [Figure 16] FIG. 2 is a diagram for explaining Example 2-2. [Figure 17] FIG. 2 is a diagram for explaining Example 2-2. [Figure 18] FIG. 13 is a diagram for explaining Example 3-1. [Figure 19] FIG. 13 is a diagram for explaining Example 3-1. [Figure 20] FIG. 13 is a diagram for explaining Example 3-1. [Figure 21] FIG. 13 is a diagram for explaining Example 3-2. [Figure 22] FIG. 13 is a diagram for explaining Example 3-2. [Figure 23] FIG. 13 is a diagram for explaining a calculation example of θ. [Figure 24] FIG. 13 is a diagram for explaining a calculation example of θ. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] 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.

[0012] (System configuration, Airy Beam overview) Fig. 1 shows an example of the configuration of a wireless communication system common to the first to third embodiments. As shown in Fig. 1, the wireless communication system in this embodiment has a transmitting device 100 and a receiving device 200. The transmitting device 100 has a transmitting antenna 110, a transmitting unit 120, a signal processing unit 130, a control unit 140, and a distance acquisition unit 150. The receiving device 200 has a receiving antenna 210, a receiving unit 220, a signal processing unit 230, and a control unit 240. Note that, for convenience of illustration, the transmitting device 100 and the receiving device 200 are placed close to each other, but in reality they are farther apart.

[0013] 1, the transmitting device 100 and the receiving device 200 are shown separately, but the transmitting device 100 and the receiving device 200 may be provided in one device (device A). In this case, communication is performed between device A and the other device. Also, the distance acquisition unit 150 may not be provided.

[0014] The transmitting antenna 110 in this embodiment can generate an Airy beam whose trajectory has a property of bending in one direction by giving a special initial phase distribution. Specifically, when the antenna is viewed as a two-dimensional plane, the Airy beam can be generated by giving, for example, a third-order phase change to the two-dimensional plane. The receiving antenna 210 may have the same configuration as the transmitting antenna 110, or may be a general antenna that does not have a special configuration for the Airy beam.

[0015] The signal processing unit 130 of the transmitting device 100 generates, from the input data, a digital signal to be transmitted on a carrier wave. The transmitting 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 110.

[0016] The distance acquisition unit 140 acquires the distance between the transmitting antenna 110 and the receiving antenna 210. Any method may be used to acquire the distance. For example, the distance may be acquired from an external server, the positions of the transmitting antenna 110 and the receiving antenna 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.

[0017] The control unit 140 determines the angle of the transmitting antenna 110 based on, for example, the distance between the transmitting antenna 110 and the receiving antenna 210, and notifies the transmitting antenna 110 of the angle. The transmitting antenna 110 includes an angle adjustment mechanism (angle adjustment unit) and adjusts the angle using the angle adjustment mechanism.

[0018] In addition, the control unit 140 can determine the initial phase of each antenna element of the transmitting antenna 110 based on, for example, the distance between the transmitting antenna 110 and the receiving antenna 210, notify the transmitting unit 120 or the transmitting antenna 110 of the determined initial phase, and generate an Airy beam using the initial phase.

[0019] The transmitting unit 120, the signal processing unit 130, the control unit 140, and the distance acquisition unit 150 may be called a transmitting circuit, a signal processing circuit, a control circuit, and a distance acquisition circuit, respectively. Moreover, the "signal processing unit 130, the control unit 140, and the distance acquisition unit 150" may be collectively called a processor (or a CPU).

[0020] The receiving unit 220 of the receiving device 200 converts an analog signal received by the receiving antenna 210 into a digital signal and transmits it to the signal processing unit 230. The signal processing unit 230 generates data from the digital signal. The signal processing unit 230 can also perform interference removal processing such as MIMO equalization processing and SIC. The control unit 240 can instruct the signal processing unit 230 whether to perform interference removal processing or not depending on the transmission method of the transmitting antenna 110 (e.g., depending on whether the first embodiment or the second embodiment is used).

[0021] The receiving unit 220, the signal processing unit 230, and the control unit 240 may be called a receiving circuit, a signal processing circuit, and a control circuit, respectively. Moreover, the "signal processing unit 230 and the control unit 240" may be collectively called a processor (or a CPU).

[0022] Fig. 2 is a diagram showing an example of the intensity distribution of radio waves on a certain plane facing the transmitting antenna 110 that generates the Airy beam. In Fig. 2, the darker the area, the stronger the power. As shown in Fig. 2, the Airy beam has a spread (side lobes) of 90 degrees in the x-axis and y-axis directions around the main lobe, which has strong power. Therefore, interference with other radio waves occurs in places with this spread.

[0023] Fig. 3 is a diagram showing an image of a cross section of an Airy beam on an xz plane when the transmitting antenna 110 is placed on the xy plane. In the example shown in Fig. 3, the beam is shown to be curved to the right. In addition, in the example shown in Fig. 3, there is a side lobe on the left side of the main lobe.

[0024] Fig. 4 shows an example of the configuration of a transmitting antenna 110 that generates an Airy beam. Fig. 4 is a front view of a planar transmitting antenna 110. As shown in Fig. 4, the antenna has a configuration in which a plurality of antenna elements (which may be called patch antennas) are provided on a planar substrate. For example, each antenna element has a variable phase shifter, and it is possible to give a predetermined initial phase to an electromagnetic wave (radio wave) for each antenna element. The degree of bending of the Airy beam can be changed depending on the initial phase given to each antenna element.

[0025] FIG. 5 is a diagram showing another example of the configuration of the transmitting antenna 110 that generates an Airy beam. In this example, the shape of the transmitting antenna 110 as viewed from the front is, for example, circular. FIG. 5 shows an image of a cross section of the transmitting antenna 110 cut along a plane including the axis of the radio wave transmission direction of the transmitting antenna 110. As shown in FIG. 5, the transmitting antenna 110 in this example has an antenna 111 that outputs radio waves, a plane wave generating lens 112, a phase modulation lens 113, and a Fourier transform lens 114. If the plane as viewed from the front of the transmitting antenna 110 is an xy plane, the phase modulation lens can give an initial phase to each point (xy coordinates) on the xy plane. By using a phase modulation lens that realizes a desired initial phase, a desired Airy beam can be generated.

[0026] In addition, in the configuration of FIG. 5, if the radio wave transmitted from the antenna 111 is a plane wave or close to a plane wave, the plane wave generating lens 112 may be omitted. For example, if the distance from the antenna 111 to the phase modulation lens 113 is 50 times the wavelength or more, the radio wave transmitted from the antenna 111 is close to a plane wave, so the plane wave generating lens 112 may be omitted. Even if this is not the case, the plane wave generating lens 112 may be omitted by sacrificing the characteristics of the bending radio wave to some extent. In the latter case, the side lobes and the like will be slightly disturbed from the desired bending radio wave, but there is an advantage in that the entire antenna can be made compact by eliminating the plane wave generating lens 112. Alternatively, by using an antenna that transmits a plane wave as the antenna 111, the plane wave generating lens 112 can be omitted without sacrificing performance.

[0027] Hereinafter, the first to third embodiments of the present invention will be described as embodiments of the present invention. Although the first to third embodiments may use either the configuration of Fig. 4 or the configuration of Fig. 5, it is assumed that the configuration of Fig. 4 is mainly used as an example.

[0028] (First embodiment) Wireless communication technologies using the millimeter wave, sub-THz, or THz bands have the advantage of being able to improve transmission capacity by using a wide bandwidth. On the other hand, when implementing spatial multiplexing technologies such as MIMO technology, the signal processing load increases due to the wider bandwidth. There is a practical limit to the signal processing capabilities of wireless communication devices, and spatial multiplexing technologies using wide bandwidths have been restricted in terms of signal processing load.

[0029] In other words, there is a problem that the number of spatial multiplexing is limited or the available bandwidth is limited due to the limitation of the signal processing capacity. Also, there is a problem of how to remove interference between signals by low-load signal processing.

[0030] In the first embodiment, the above problem is solved by using the characteristics of an Airy beam. That is, as described above, an Airy beam has a characteristic that a side lobe appears only on one side of the receiving side. In conventional technology, this characteristic is hardly used in wireless communication, but in the first embodiment, the above problem is solved by utilizing this characteristic.

[0031] <Overview and Example 1-1> The outline of the first embodiment will be described with reference to Figures 6 to 8. Figure 8 is a configuration diagram according to Example 1-1 of the first embodiment, and Figures 6 and 7 are explanatory diagrams using the conventional technology for comparison with Figure 8.

[0032] In all cases of FIGS. 6 to 8, the transmitting antenna 110 has sub-transmitting antennas #1 and #2, and the receiving antenna 210 has sub-receiving antennas #1 and #2, and performs spatial multiplexing communication with a spatial multiplex number of 2.

[0033] When performing spatial multiplexing of wireless signals using multiple antennas, it is necessary to remove interference between the antennas. Figure 6 shows an example of removing interference between antennas by signal processing. The example in Figure 6 has the problem of increasing the amount of signal processing.

[0034] Fig. 7 shows an example of a case where interference is removed by placing a physical shield between the transmitting antenna 110 and the receiving antenna 210. In the example of Fig. 7, the burden of having to provide the shield is imposed.

[0035] Fig. 8 shows Example 1-1 of the first embodiment. In Example 1-1, as shown in Fig. 8, Airy beams are simultaneously transmitted from each of the two sub-transmitting antennas of the transmitting antenna 110, and beams are generated on the transmitting side so that the side lobes of each Airy beam appear outside the antenna. This makes it possible to carry two different data on each beam and perform spatial multiplexing.

[0036] In FIG. 8, a communication path for a stream from the sub transmitting antenna #1 to the sub receiving antenna #1 is called a wireless communication path 1, and a communication path for a stream from the sub transmitting antenna #2 to the sub receiving antenna #2 is called a wireless communication path 2.

[0037] At this time, the side lobe of the Airy beam transmitted from the sub-transmitting antenna #1 appears on the opposite side of the wireless communication path 2 with respect to the wireless communication path 1. Also, the side lobe of the Airy beam transmitted from the sub-transmitting antenna #2 appears on the opposite side of the wireless communication path 2 with respect to the wireless communication path 1.

[0038] Therefore, the main lobe and side lobe of the Airy beam transmitted from sub-transmitting antenna #1 do not interfere with the side lobe of the Airy beam transmitted from sub-transmitting antenna #2. Also, the main lobe and side lobe of the Airy beam transmitted from sub-transmitting antenna #2 do not interfere with the side lobe of the Airy beam transmitted from sub-transmitting antenna #1. This enables interference-free signal transmission without the need for signal processing or obstructions.

[0039] The number of sub-antennas of each of the transmitting antenna 110 and the receiving antenna 210 is not limited to two as in Example 1-1. It may be any number equal to or greater than three. Below, a case in which the number of sub-antennas of each of the transmitting antenna 110 and the receiving antenna 210 is four will be described as Example 1-2, and a case in which the number of sub-antennas of each of the transmitting antenna 110 and the receiving antenna 210 is eight will be described as Example 1-3.

[0040] <Example 1-2> Example 1-2 shows an example in which the number of sub-antennas of each of the transmitting antenna 110 and the receiving antenna 210 is four.

[0041] Fig. 9 shows the configuration of the transmitting antenna 110 as viewed from the front. The receiving antenna 210 has a similar configuration. As shown in Fig. 9, the transmitting antenna 110 has sub-transmitting antennas #1 to #4, each of which has multiple antenna elements as shown in the figure and is capable of generating an Airy beam.

[0042] The receiving antenna 210 includes sub-receiving antennas #1 to #4 similar to those shown in Fig. 9. The sub-receiving antennas #1 to #4 do not need to have the function of generating an Airy beam. 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.

[0043] Fig. 10 is a diagram showing the intensity distribution of the Airy beam transmitted from the transmitting antenna 110 (the intensity distribution on the opposing surface of the transmitting antenna 110). As shown in Fig. 10, the side lobe of each sub-transmitting antenna occurs on the side opposite to the side on which the other sub-transmitting antenna exists. This makes it possible to perform spatial multiplexing transmission with a spatial multiplexing number of 4 without interference between the sub-transmitting antennas.

[0044] <Example 1-3> Example 1-3 shows a case where the number of sub-antennas of each of the transmitting antenna 110 and the receiving antenna 210 is eight.

[0045] Fig. 11 shows the configuration of the transmitting antenna 110 as viewed from the front. The receiving antenna 210 has a similar configuration. As shown in Fig. 11, the transmitting antenna 110 has sub-transmitting antennas #1 to #8, each of which has multiple antenna elements as shown in the figure and is capable of generating an Airy beam.

[0046] The receiving antenna 210 includes sub-receiving antennas #1 to #8 similar to those shown in Fig. 11. The sub-receiving antennas #1 to #8 do not need to have a function for generating an Airy beam. The sub-transmitting antennas #1, #8, #7 face the sub-receiving antennas #7, #8, #1, the sub-transmitting antennas #2, #6 face the sub-receiving antennas #6, #2, and the sub-transmitting antennas #3, #4, #5 face the sub-receiving antennas #5, #4, #3.

[0047] Fig. 12 is a diagram showing the intensity distribution of the Airy beam transmitted from the transmitting antenna 110 (the intensity distribution on the opposing surface of the transmitting antenna 110). As shown in Fig. 12, the side lobes of each sub-antenna appear on the outer side with respect to the center side of the eight sub-transmitting antennas.

[0048] In this case, for example, no interference occurs between the side lobe of sub-transmitting antenna #1 and the side lobes of sub-transmitting antennas #3 to #7, but interference may occur between the side lobe of sub-transmitting antenna #1 and the side lobes of sub-transmitting antennas #2 and #8.

[0049] Thus, Example 1-3 is an example that allows some interference. That is, in Example 1-3, radio waves are transmitted so as to allow partial overlap of side lobes. For the part where the side lobes overlap, the receiving device 200 performs interference removal using a method such as SIC (successive interference cancellation). This allows the number of spatial multiplexes to be increased while maintaining a lower amount of calculation than the equalization process of full MIMO.

[0050] <Example 1-4> Example 1-4 is applicable to any of Examples 1-1 to 1-3. Example 1-4 is also applicable to the second and third embodiments. In Example 1-4, the degree of bending of the Airy beam is adjusted by adaptively adjusting the size of an antenna composed of multiple antenna elements in a sub-transmitting antenna constituting the transmitting antenna 110. This makes it possible to adjust the distance or position to which the Airy beam reaches. Such size adjustment can be performed by the control unit 140, for example.

[0051] An example will be described with reference to Fig. 13 and Fig. 14. As shown in Fig. 13, in one sub-transmitting antenna, 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.

[0052] Fig. 14 shows a state where the transmitting antenna 110 shown in Fig. 13 is viewed obliquely. 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 antenna located farther away.

[0053] In other words, by adjusting the area of ​​the multiple antenna elements in the transmitting antenna 110 for generating an Airy beam, the distance that the Airy beam reaches can be adjusted so that radio waves reach the desired position of the receiving antenna 110.

[0054] <Advantages of the First Embodiment> The technology according to the first embodiment makes it possible to increase the amount of data that can be simultaneously transmitted and received without increasing the signal processing load in wireless communication using the millimeter wave band, sub-THz band, or THz band and using a wide band. In other words, spatial multiplexing transmission using a wide band can be achieved with low-load signal processing. This allows an increase in transmission capacity.

[0055] Second embodiment Next, a second embodiment will be described. In wireless communication technology using the millimeter wave band, sub-THz band, or THz band, it is desirable to increase the spatial utilization efficiency of radio waves by narrowing the beam width and creating a closed space such as a personal cell, that is, an environment in which radio waves do not leak to other areas. However, in conventional technology, side lobes of radio waves exist, making it difficult to reduce the leakage of radio waves.

[0056] In the second embodiment, the above problem is solved by using the characteristics of an Airy beam. That is, as described above, an Airy beam has a characteristic that a side lobe appears only on one side of the receiving side. In conventional technology, this characteristic is hardly used in wireless communication, but in the second embodiment, the above problem is solved by utilizing this characteristic.

[0057] <Example 2-1> Example 2-1 of the second embodiment will be described with reference to Fig. 15. As shown in Fig. 15, the transmitting antenna 110 has a sub-transmitting antenna #1 and a sub-transmitting antenna #2, and the receiving antenna 210 has a sub-receiving antenna #1 and a sub-receiving antenna #2, and performs spatial multiplexing communication with a spatial multiplexing number of 2.

[0058] In Example 2-1, as shown in Fig. 15, Airy beams are simultaneously transmitted from each of the two sub-transmitting antennas of the transmitting antenna 110, and the transmitting side generates beams so that the side lobes of each Airy beam appear inside the antenna. This makes it possible to carry two different data on each beam for spatial multiplexing, and to create a closed space by preventing the data from leaking to the outside. In the receiving device 200, each data is extracted by performing interference removal processing such as MIMO equalization processing.

[0059] In FIG. 15, the communication path of the stream from the sub transmitting antenna #1 to the sub receiving antenna #1 is called wireless communication path 1, and the communication path of the stream from the sub transmitting antenna #2 to the sub receiving antenna #2 is called wireless communication path 2.

[0060] At this time, the side lobe of the Airy beam transmitted from the sub-transmitting antenna #1 appears on the wireless communication channel 2 side relative to the wireless communication channel 1. Moreover, the side lobe of the Airy beam transmitted from the sub-transmitting antenna #2 appears on the wireless communication channel 1 side relative to the wireless communication channel 2. Conversely, a region without a side lobe of the Airy beam transmitted from the sub-transmitting antenna #1 appears on the opposite side of the wireless communication channel 2 side relative to the wireless communication channel 1. Moreover, a region without a side lobe of the Airy beam transmitted from the sub-transmitting antenna #2 appears on the opposite side of the wireless communication channel 1 side relative to the wireless communication channel 2.

[0061] Therefore, the main lobe and side lobe of the Airy beam transmitted from sub-transmitting antenna #1, and the main lobe and side lobe of the Airy beam transmitted from sub-transmitting antenna #2 appear in the closed internal space sandwiched between wireless communication paths 1 and 2, thereby suppressing leakage of radio waves to the outside.

[0062] In other words, it is possible to prevent radio waves from either sub-transmitting antenna #1 or sub-receiving antenna #2 from leaking outside the wireless communication path between the main lobe of the Airy beam from sub-transmitting antenna #1 to sub-receiving antenna #1 and the main lobe of the Airy beam from sub-transmitting antenna #2 to sub-receiving antenna #2.

[0063] The number of sub-antennas of each of the transmitting antenna 110 and the receiving antenna 210 is not limited to two as in Example 2-1, but may be any number equal to or greater than three.

[0064] <Example 2-2> In Example 2-2, an example will be described in which the number of sub-antennas of each of the transmitting antenna 110 and the receiving antenna 210 is four.

[0065] Fig. 16 shows the configuration of the transmitting antenna 110 as viewed from the front. The receiving antenna 210 has a similar configuration. As shown in Fig. 16, the transmitting antenna 110 has sub-transmitting antennas #1 to #4, each of which has multiple antenna elements as shown in the figure and is capable of generating an Airy beam.

[0066] The receiving antenna 210 includes sub-receiving antennas #1 to #4 similar to those shown in Fig. 16. The sub-receiving antennas #1 to #4 do not need to have the function of generating an Airy beam. 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.

[0067] Fig. 17 is a diagram showing the intensity distribution of the Airy beam transmitted from the transmitting antenna 110 (the intensity distribution on the opposing surface of the transmitting antenna 110). As shown in Fig. 17, the side lobe of each sub-transmitting antenna occurs on the side where the other sub-antennas exist. In other words, the side lobe of each sub-antenna occurs on the center side of the four sub-transmitting antennas. This makes it possible to perform spatial multiplexing transmission with a spatial multiplexing number of 4 while suppressing interference to the outside of the sub-transmitting antennas.

[0068] <Effects of the second embodiment> The technology according to the second embodiment can create an environment in which radio waves do not leak outside of desired areas in wireless communication using the millimeter wave band, sub-THz band, or THz band and using a wide band, and can improve space utilization efficiency. In other words, the number of users who can communicate in a certain area can be increased, and the total capacity of transmission and reception performed in a certain area (space) can be improved. In addition, a space in which radio waves do not leak can be created.

[0069] <Combination of the first and second embodiments> It is also possible to switch between the method of the first embodiment, which prevents interference between Airy beams, and the method of the second embodiment, which allows interference between Airy beams and prevents interference outside the wireless communication path between multiple Airy beams.

[0070] For example, in an environment where interference to the outside of the Airy beam can be tolerated, the transmitting device 100 decides to use the method of the first embodiment and performs antenna control of the first embodiment. Also, in an environment where interference to the outside of the Airy beam cannot be tolerated, the transmitting device 100 decides to use the method of the second embodiment and performs antenna control of the second embodiment.

[0071] When the transmitting device 100 determines the method, it notifies the receiving device 200 of the determined method. The receiving device 200 performs reception processing according to the notified method. For example, when the receiving device 200 is notified that the method of the second embodiment is to be used, it performs interference removal processing in signal reception from the transmitting antenna 110.

[0072] Third embodiment Next, a third embodiment will be described. The third embodiment can be applied to any system configuration that includes a transmitting antenna 110 that transmits an Airy beam. The third embodiment may be applied to the first embodiment or the second embodiment.

[0073] In a real environment where communication is performed between the transmitting device 100 and the receiving device 200, if the distance between the transmitting device and the receiving device changes, it is necessary to be able to respond to the change in the distance between the transmitting device and the receiving device. When using conventional unbending radio waves, transmission and reception could be performed by facing the transmitting antenna 110 and the receiving antenna 120 regardless of the distance.

[0074] On the other hand, when using a curved radio wave such as an Airy beam, the trajectory of the radio wave curves, so it is necessary to ensure that the main lobe of the Airy beam transmitted from the transmitting antenna 110 reaches the position of the receiving antenna 120.

[0075] <Summary> In order to solve the above problems, in the third embodiment, an example in which the transmitting device 100 is equipped with a mechanical distance adjustment mechanism is described as Example 3-1, and an example in which the position where the Airy beam arrives is adjusted by adjusting the initial phase for generating the Airy beam in the transmitting antenna 110 is described as Example 3-2.

[0076] Although it is assumed that Examples 3-1 and 3-2 are implemented in combination, each of Examples 3-1 and 3-2 may be implemented independently.

[0077] Specifically, in Example 3-1, a mechanical distance adjustment mechanism adjusts the degree to which the curved radio waves are transmitted obliquely so that the main lobe of the Airy beam can be received by the receiving antenna 210. Also, in Example 3-2, the degree to which the Airy beam is curved is adjusted by adjusting the initial phase of the Airy beam generation so that the receiving antenna 210 can receive the main lobe of the Airy beam.

[0078] In either case of Example 3-1 or Example 3-2, by acquiring the distance between the transmitting antenna 110 and the receiving antenna 210 by the distance acquisition unit 150, the control unit 140 can determine the angle of the transmitting antenna 110 or the initial phase of the transmitting antenna 110 based on the distance. Also, the control unit 140 may determine both the angle of the transmitting antenna 110 and the initial phase of the transmitting antenna 110 based on the distance. Each example will be described below.

[0079] <Example 3-1> In Example 3-1, as the distance adjustment mechanism described above, the transmitting device 100 is provided with an angle adjustment mechanism (angle adjustment unit) that adjusts the physical angle (direction) of the transmitting antenna 110. An image of appropriately transmitting an Airy beam to the receiving side by adjusting the angle is shown in Fig. 18. In Fig. 18, there is a transmitting device and a receiving device on one side, and also a transmitting device and a receiving device on the other side, and by adjusting the angle of the transmitting antenna, the main lobe of the Airy beam is allowed to reach the receiving antenna.

[0080] An example of angle adjustment using an angle adjustment mechanism is shown in Fig. 19. Here, it is assumed that there is an angle adjustment mechanism at the connection part between the transmitting antenna 110 and the main body of the transmitting device 100.

[0081] As an example, the transmitting device 100 and the receiving device 200 are each provided at a certain height from the ground, and the transmitting antenna 110 is oriented horizontally before the angle adjustment by the angle adjustment mechanism. In other words, when the transmitting antenna 110 is viewed as a plane, the perpendicular line of the plane is parallel to the ground surface. Fig. 19(a) shows a state in which the angle adjustment mechanism has tilted the transmitting antenna 110 upward by θ1 degrees. Fig. 19(b) shows a state in which the angle adjustment mechanism has tilted the transmitting antenna 110 upward by θ2 degrees. Fig. 19(c) shows a state in which the angle adjustment mechanism has tilted the transmitting antenna 110 upward by θ3 degrees, where θ1<θ2<θ3.

[0082] For example, let us assume that all of the Airy beams in Fig. 19(a) to (c) are bent toward the ground, and the order of magnitude of the bending is (a)<(b)<(c) in Fig. 19. In this case, the transmitting antenna 110 in (a) can transmit radio waves to the receiving antenna 210 located at the farthest position, and the transmitting antenna 110 in (c) can transmit radio waves to the receiving antenna 210 located at the closest position. The transmitting antenna 110 in (b) can transmit radio waves to the receiving antenna 210 located between them. Fig. 20 shows an image of the main lobe of the Airy beam reaching the receiving side when θ1=5 degrees, θ2=10 degrees, and θ3=15 degrees.

[0083] For example, in the example of Figure 20, when the distance acquisition unit 150 acquires the distance A shown in (a) as the distance between the transmitting antenna 110 and the receiving antenna 210, the control unit 140 controls the initial phase of the transmitting antenna 110 so that the degree of curvature of the Airy beam is as shown in Figure 20(a), and sets the angle of the transmitting antenna 110 to the angle shown in Figure 20(a).

[0084] Also, for example, when it is determined that the initial phase of the transmitting antenna 110 will have a degree of curvature of the Airy beam as shown in Figure 20(a), if the distance acquisition unit 150 acquires the distance A shown in (a) as the distance between the transmitting antenna 110 and the receiving antenna 210, the control unit 140 sets the angle of the transmitting antenna 110 to the angle shown in Figure 20(a).

[0085] Also, for example, when it is determined that the initial phase of the transmitting antenna 110 will have a degree of curvature of the Airy beam as shown in Figure 20(a), if the distance acquisition unit 150 acquires a distance between the transmitting antenna 110 and the receiving antenna 210 that is shorter than the distance A shown in (a), the control unit 140 sets the angle of the transmitting antenna 110 to an angle smaller than the angle shown in Figure 20(a).

[0086] <Example 3-2> When using a configuration of the transmitting antenna 110 consisting of a plurality of antenna elements as shown in Fig. 4, each antenna element is provided with a variable phase shifter. The degree of bending of the Airy beam can be set by setting the initial phase (initial phase of the transmitted electromagnetic wave (radio wave)) in each antenna element. When using a configuration of the transmitting antenna 110 using a phase modulation lens (which may be called a phase modulation plate) as shown in Fig. 5, when the transmitting antenna 110 is viewed as an xy plane, the degree of bending of the Airy beam can be set by setting the initial phase given to each xy coordinate position in the phase modulation lens. When using a phase modulation lens, multiple phase modulation lenses each having a different initial phase distribution are prepared, and a phase modulation lens with a desired degree of bending is selected and used.

[0087] A method for setting the initial phase to be given to the radio wave transmitted from the transmitting antenna 110 will be described below.

[0088] i(∂φ / ∂ξ)+(1 / 2)(∂ 2 φ / ∂s 2 )=0 One solution to the above Schrödinger equation is the following Airy accelerating solution (hereafter referred to as the Airy equation), which governs the behavior of an Airy beam.

[0089] φ(ξ,s)=Ai(s-(ξ / 2) 2 )exp(i(sξ / 2)-i(ξ 3 / 12)) The symbols in the Airy system have the following meanings:

[0090] Ai: Airy function φ: electric field envelope s=x / x0: dimensionless traverse coordinate x0: arbitrary traverse scale ξ=z / kx0 2 :normalized propagation distance k=2πn / λ0 Here, a one-dimensional antenna is assumed, where x is the axial position in the direction of the transmitting antenna (the direction in which the antenna elements are arranged), and z is the position (distance) in the direction in which the radio waves propagate.

[0091] The Airy formula expresses the strength and phase of radio waves (main lobe) when they propagate along a parabolic trajectory, and as a result, expresses the trajectory that the radio waves will curve in space. Radio waves that appear in the Airy formula in this way are called Airy beams. If the initial conditions of an Airy beam are known using the Airy formula, it is possible to know what kind of parabolic trajectory the Airy beam will follow. Conversely, it is possible to know what initial conditions are necessary for the Airy beam to follow a certain parabolic trajectory. In this case, the initial condition refers to the initial phase.

[0092] In Example 3-2, the latter feature is utilized. That is, for the desired trajectory (degree of curvature) of the Airy beam, the initial phase of each antenna element (xy coordinate points when the transmitting antenna is viewed as an xy plane) that is the initial condition is calculated, and the transmitting antenna 110 is set to output radio waves of that phase, thereby generating an Airy beam (curving radio waves) with a desired trajectory. The initial conditions required for the Airy beam to have a certain parabolic trajectory can be found by calculation using the Airy formula. The specific method in Example 3-2 is explained below.

[0093] In Example 3-2, as an example, a desired trajectory is calculated by using x0, which is a scale factor in the Airy formula described above. This will be explained with reference to Figs. 21 and 22.

[0094] Here, the trajectory (degree of curvature) of the Airy beam shown in Fig. 21 is used as a reference, and the trajectory (degree of curvature) of the Airy beam is adjusted as shown in Fig. 22. Also, here, it is assumed that in Fig. 21, a transmitting antenna is on the x-axis and a receiving antenna is at point A, and in Fig. 22, a transmitting antenna is on the x-axis and a receiving antenna is at point B, and with regard to the distance from the transmitting antenna to the receiving antenna, the state in Fig. 21 is used as a reference, and an initial phase is set so as to obtain a desired distance in Fig. 22.

[0095] Let us assume that there is a transmitting antenna with a size of 40 cm (a length of 40 cm in one dimension) on the x-axis of Fig. 21 (the horizontal line above -20, 0, and 20), and for convenience, the position (x-coordinate) of that transmitting antenna is expressed as -20 to 20. The same is true for Fig. 22. The z-axis represents the distance of the radio waves radiated from the antenna. For convenience, the z-axis direction in Fig. 21 ranges from 0 to 1000, and the z-axis direction in Fig. 22 ranges from 0 to 2000.

[0096] In the example shown in Figure 21, when z = 0, the main lobe of the radio wave (where the intensity is at its maximum) is at x = 0, and due to radio wave propagation, when z = 1000, the location corresponding to x = 20 becomes the main lobe.

[0097] On the other hand, in the example of Fig. 22, when z=0, the main lobe of the radio wave is at x=0 as in Fig. 21, but when z=1000, the main lobe is near the location corresponding to x=5, and when z=2000, the main lobe is at the location corresponding to x=20. Therefore, compared to the case of Fig. 21, in the case of Fig. 22, it can be seen that the degree of bending of the Airy beam has changed, and the reach of the Airy beam (main lobe) for the same x coordinate position (here, x=20) has become longer. An example of a method for setting the initial phase of the transmitting antenna for such adjustments will be described below.

[0098] Here, it is assumed that the initial phase corresponding to the reference bending has already been calculated. For example, when the size of the transmitting antenna is 40 cm x 40 cm, the initial phase of the transmitting antenna for generating an Airy beam that bends 20 cm at a distance of 10 m from the transmitting antenna in the vertical direction has already been calculated. This assumption corresponds to the distance from the x-axis to point A in Figure 21 being 10 m.

[0099] The above-mentioned predetermined initial phase may be calculated directly by the control unit 140 from a two-dimensional equation of the above-mentioned Airy equation, or may be input from outside to the control unit 140 of the transmission device 100. When calculating the initial phase with respect to the reference, the scale factor x0 in the above-mentioned Airy equation is set to 1.

[0100] Here, assuming that the desired distance at position x where the reference distance is obtained is a times (a=2 in the case of Figure 22 where Figure 21 is used as the reference) the reference distance (10 m in the above example), an example of a method for setting the initial phase that can obtain a distance that is a times the reference distance will be described.

[0101] In the above Airy formula, k is calculated based on the wavelength length, etc., but when the same transmitting antenna elements are used and only the distance is changed, the value of k remains the same, so for simplicity in the following explanation, k = 1.

[0102] To obtain a distance a times the reference distance, the scale factor x0 can be set to √a (root a). If x0=√a, then s=x / √a. In other words, by scaling and setting the initial phase by 1 / √a, a distance a times the reference distance can be obtained. Specifically, when a=2, the initial phase at position x in the reference (e.g., FIG. 21) is set as the initial phase at position x / √2 in the desired state (e.g., FIG. 22). For example, if the initial phase at position 10 on the x-axis in the reference (e.g., FIG. 21) is 30°, then the initial phase at position 10 / √2 on the x-axis in the desired state (e.g., FIG. 22) is set as 30°.

[0103] In addition, if the reference state is shown in Figure 21 and the desired state is shown in Figure 22, the phase values ​​at positions less than x = -20 / √2 and positions greater than x = 20 / √2 in Figure 22 correspond to phase values ​​at positions that do not exist in Figure 21.

[0104] In such a case, only antenna elements in the range of x=-20 / √2 to 20 / √2 in Fig. 22 may be used. Also, the standard antenna size may be (40×√2)×(40×√2), and in this case, the initial phase for generating an Airy beam that is bent 20 cm in the x direction at a distance of 10 m vertically from the transmitting antenna may be calculated using the Airy formula (or input from outside), and this initial phase may be scaled and set by 1 / √a to obtain the desired state (e.g., Fig. 22).

[0105] In the above explanation, a one-dimensional antenna having only the x-axis has been used as an example for the sake of ease of understanding. However, for a two-dimensional antenna having both the x-axis and the y-axis, the equation for y can be obtained by replacing x with y in the Airy equation.

[0106] In this case, the phase of a point on the (x, y) coordinates of the transmitting antenna can be obtained by combining (multiplying) the phase obtained from the equation for x and the phase obtained from the equation for y.

[0107] Here, consider a transmitting antenna 110 with a size of A×A as shown in Fig. 23. In this case, assume that it is desired to deliver the main lobe of the Airy beam to a receiving antenna placed at point C at a distance d from the transmitting antenna as shown in Fig. 24.

[0108] In this case, the angle θ shown in FIG. 24 is set so that cos=A / d. In other words, θ=arccos(A / d). This makes it possible to determine the angle of the transmitting antenna 110. If d and θ are known, the length of F shown in FIG. 24 can be known, so that the initial phase can be calculated by the method described above. The calculated initial phase is set to the transmitting antenna 110.

[0109] <Effects of the third embodiment> The technology according to the third embodiment makes it possible to realize wireless communication using Airy beams even when the distance between the transmitting antenna and the receiving antenna is variable.

[0110] (Summary of the first embodiment) Regarding the first embodiment, this specification discloses at least a transmitting device and a wireless spatial multiplexing transmission method according to the following items. (Section 1) a transmitting antenna having a plurality of sub-transmitting antennas each transmitting an Airy beam; At the receiving side, spatial multiplexing is performed using the plurality of Airy beams transmitted from the plurality of sub-transmitting antennas so that interference is not caused by radio waves transmitted from the plurality of sub-transmitting antennas. Transmitting device. (Section 2) At a receiving side, a plurality of sub-receiving antennas corresponding to the plurality of sub-transmitting antennas are provided; Each of the sub-transmitting antennas transmits an Airy beam such that a side lobe of the transmitted Airy beam does not reach any sub-receiving antenna other than the corresponding sub-receiving antenna. A transmitting device as described in item 1. (Section 3) The transmitting antenna includes four or more sub-transmitting antennas, and the transmitting device performs spatial multiplexing with a spatial multiplexing number of four or more. A transmitting device as described in claim 1 or 2. (Section 4) A wireless spatial multiplexing transmission method implemented by a transmitting device having a transmitting antenna including a plurality of sub-transmitting antennas each of which transmits an Airy beam, comprising: At the receiving side, spatial multiplexing is performed using the plurality of Airy beams transmitted from the plurality of sub-transmitting antennas so that interference is not caused by radio waves transmitted from the plurality of sub-transmitting antennas. A wireless spatial multiplexing transmission method.

[0111] (Summary of the second embodiment) Regarding the second embodiment, this specification discloses at least a transmitting device and a wireless spatial multiplexing transmission method according to the following items. (Section 1) a transmitting antenna having a plurality of sub-transmitting antennas each transmitting an Airy beam; A plurality of sub-transmitting antennas are used for spatial multiplexing so that radio waves transmitted from the plurality of sub-transmitting antennas do not leak outside a wireless communication path between the plurality of sub-transmitting antennas and a receiving side. Transmitting device. (Section 2) At a receiving side, a plurality of sub-receiving antennas corresponding to the plurality of sub-transmitting antennas are provided; Each of the sub-transmitting antennas transmits an Airy beam such that a side lobe of the transmitted Airy beam occurs inside the wireless communication path. A transmitting device as described in item 1. (Section 3) The transmitting antenna includes four or more sub-transmitting antennas, and the transmitting device performs spatial multiplexing with a spatial multiplexing number of four or more. A transmitting device as described in claim 1 or 2. (Section 4) A wireless spatial multiplexing transmission method implemented by a transmitting device having a transmitting antenna including a plurality of sub-transmitting antennas each of which transmits an Airy beam, comprising: A plurality of sub-transmitting antennas are used for spatial multiplexing so that radio waves transmitted from the plurality of sub-transmitting antennas do not leak outside a wireless communication path between the plurality of sub-transmitting antennas and a receiving side. A wireless spatial multiplexing transmission method.

[0112] (Summary of the third embodiment) Regarding the third embodiment, this specification discloses at least the following transmitting device and transmitting method. (Section 1) a transmitting antenna for transmitting an Airy beam; a distance acquisition unit that acquires a distance between the transmitting antenna and a receiving antenna that receives the Airy beam; a control unit that adjusts an angle of the transmitting antenna or an initial phase to be applied to a radio wave transmitted from the transmitting antenna according to the distance; A transmitting device comprising: (Section 2) The control unit adjusts the angle depending on the distance and the degree of bending of the Airy beam. A transmitting device as described in item 1. (Section 3) The control unit determines the initial phase by using an initial phase that is a reference and a scale factor according to the distance. A transmitting device as described in claim 1 or 2. (Section 4) A transmission method performed by a transmitting device having a transmitting antenna that transmits an Airy beam, comprising: a distance acquisition step of acquiring a distance between the transmitting antenna and a receiving antenna that receives the Airy beam; a control step of adjusting an angle of the transmitting antenna or an initial phase to be given to a radio wave transmitted from the transmitting antenna according to the distance; A transmission method comprising:

[0113] 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]

[0114] 100 Transmitting device 110 Transmitting Antenna 120 Transmitter 130 Signal Processing Section 140 Control section 150 Distance acquisition part 200 Receiving device 210 Receiving antenna 220 Receiving unit 230 Signal Processing Unit 240 Control Unit

Claims

1. A transmitting antenna for transmitting an Airy beam; a distance acquisition unit that acquires a distance between the transmitting antenna and a receiving antenna that receives the Airy beam; a control unit that adjusts an angle of the transmitting antenna and an initial phase to be given to a radio wave transmitted from the transmitting antenna according to the distance; The control unit adjusts the angle using the size of the transmitting antenna and the distance. Transmitting device.

2. The control unit adjusts the angle depending on the distance and the degree of bending of the Airy beam. The transmitting device according to claim 1 .

3. The control unit determines the initial phase by using an initial phase that is a reference and a scale factor according to the distance.

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

4. A transmission method performed by a transmitting device having a transmitting antenna that transmits an Airy beam, comprising: a distance acquisition step of acquiring a distance between the transmitting antenna and a receiving antenna that receives the Airy beam; a control step of adjusting an angle of the transmitting antenna and an initial phase to be given to a radio wave transmitted from the transmitting antenna according to the distance; In the control step, the transmitting device adjusts the angle using the size of the transmitting antenna and the distance. Transmission method.

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