Transmission device

Abstract

A transmission device that transmits a signal to a reception device provided with a plurality of reception antennas disposed at mutually different positions, the transmission device comprising a beam generation unit that generates a plurality of airy beams and transmits transmission data using the generated plurality of airy beams, which are adjusted so that main lobes of the airy beams having properties of spatially asymmetric radio waves are directed to the positions of the mutually different reception antennas and side lobes of the airy beams are not directed to the positions of any of the reception antennas.　

Description

Transmitting device

[0001] The present invention relates to a transmitting device.

[0002] Conventionally, in order to realize high-speed and large-capacity transmission, the use of wireless communication using high frequency bands such as millimeter waves, sub-THz waves, and terahertz (THz) waves has been considered. In addition, in high frequency bands such as sub-THz waves, efforts have been made to suppress interference by using an Airy beam, which has the characteristic of radio waves being spatially asymmetric (see, for example, Patent Document 1 and Non-Patent Document 1).

[0003] International Publication No. 2022 / 145008

[0004] Doohwan Lee, Yasunori Yagi, and Hiroyuki Shiba, “Multishape radio: new approach to utilizing the physical properties of electromagnetic waves”, IEICE Communications Express, Vol.11, No.9, 571-576.

[0005] Utilizing a MIMO (Multi-Input Multi-Output) spatial multiplexing scheme enables communication with a larger capacity. However, conventional MIMO (Multi-Input Multi-Output) spatial multiplexing schemes suffer from interference between multiple signals in a line-of-sight (LOS) environment. Wireless communication using high frequency bands has a wide bandwidth, which poses a problem in that it requires enormous computational resources for MIMO channel estimation and MIMO equalization processing of interfering signals.

[0006] In view of the above circumstances, an object of the present invention is to provide a technique that enables spatial multiplexing communication while reducing the signal processing load on a communication device.

[0007] One aspect of the present invention is a transmitting device that transmits signals to a receiving device equipped with multiple receiving antennas arranged at different positions, and is equipped with a beam generating unit that generates multiple Airy beams that have the property of causing radio waves to be spatially asymmetric, and are adjusted so that the main lobes of each Airy beam are directed toward the positions of different receiving antennas, and the side lobes of each Airy beam are not directed toward the positions of any of the receiving antennas, and transmits transmission data using the generated multiple Airy beams.

[0008] According to the present invention, it is possible to perform spatial multiplexing communication while reducing the signal processing load on a communication device.

[0009] FIG. 1 is a diagram illustrating an example of the configuration of a communication system according to a first embodiment; FIG. 2 is a diagram illustrating a side view of a transmission example of a transmission device according to the first embodiment; FIG. 3 is a diagram illustrating an example of the configuration of a communication system according to a second embodiment; FIG. 4 is a diagram illustrating a top view of a transmission example of a transmission device according to the second embodiment.

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] First Embodiment Fig. 1 is a diagram showing an example of the configuration of a communication system 100 according to a first embodiment. The communication system 100 includes a transmitting device 10 and a receiving device 20. The transmitting device 10 and the receiving device 20 perform wireless communication using a high frequency band. Here, the high frequency band refers to frequency bands such as millimeter waves, sub-THz waves, and terahertz waves (THz).

[0012] The transmitting device 10 is a device that transmits data to be transmitted (hereinafter referred to as "transmission data") using a high frequency band. The transmitting device 10 wirelessly transmits the transmission data to the receiving device 20 using an Airy beam. An Airy beam is characterized by radio waves that are spatially asymmetric. In other words, an Airy beam is characterized by asymmetric side lobes. Based on this characteristic, the transmitting device 10 of the present invention generates multiple Airy beams and performs spatial multiplexing transmission by adjusting the radio waves (e.g., side lobes) between the generated Airy beams so as not to interfere with each other.

[0013] For example, the transmitting device 10 can adjust the phase pattern set on the lens used to generate the Airy beam so that radio waves (e.g., side lobes) do not interfere with each other. The phase pattern set on the lens is a phase pattern that can generate an Airy beam. This allows the transmitting device 10 to suppress interference between Airy beams even when multiple Airy beams are transmitted simultaneously. The method of rotating the phase pattern set on the lens may involve physically rotating the lens. Alternatively, the lens may be made up of multiple phase-controllable elements, and the phase may be set using a method in which the phase of each element is set to be the same as when the lens is physically rotated.

[0014] The receiving device 20 receives each of the radio waves transmitted from the transmitting device 10. The receiving device 20 demodulates a signal based on the received radio waves. Specifically, the receiving device 20 detects the spatial distribution based on the intensities of the main lobe and side lobes of the received radio waves (Airy beam) and demodulates the signal.

[0015] [Configuration of Transmitting Device 10] Next, we will explain the configurations of the transmitting device 10 and the receiving device 20. First, we will explain the configuration of the transmitting device 10. The transmitting device 10 includes N (N is an integer of 2 or more) generating units 11-1 to 11-N, a signal generating unit 12, and a control unit 13.

[0016] Generators 11-1 to 11-N are arranged in parallel. Generators 11-1 to 11-N generate Airy beams for transmitting transmission data. Each generator 11 is composed of a carrier wave generator 14 and a beam generator 15. Carrier wave generator 14 generates a carrier wave and modulates the generated carrier wave with the transmission data generated by signal generator 12. Carrier wave generator 14 outputs the modulated transmission data to beam generator 15 as radio waves.

[0017] The beam generator 15 generates an Airy beam for transmitting the transmission data based on the modulated transmission data output from the carrier generator 14. The beam generator 15 is composed of a phase setting lens 151 and a Fourier lens 152. The phase setting lens 151 is composed of a mechanism capable of rotating a phase pattern. Here, the mechanism capable of rotating a phase pattern is, for example, a metasurface. The phase setting lens 151 forms a phase pattern set by the controller 13 at a predetermined rotation angle. The phase pattern set in the phase setting lens 151 is calculated based on the following equation (1). In equation (1), β represents a scaling parameter, i represents an imaginary number, and k ｘ , k ｙ represents the xy coordinate system, and α is a constant. ｘ , k ｙ )=(0,0). Details of equation (1) are described in Non-Patent Document 1, and therefore will not be described here.

[0018]

[0019] The Fourier lens 152 is set to a phase pattern obtained by modulo calculating the phase of the convex lens by 360. The phase pattern of the Fourier lens 152 may be set in advance.

[0020] Each generator 11 is disposed opposite a corresponding receiver (receiving antenna) included in the receiving device 20. Each generator 11 generates an Airy beam adjusted so that the main lobes of the generated Airy beams are directed toward the positions of the different receivers and the side lobes of the Airy beams are not directed toward the positions of any of the receivers. Each generator 11 radiates the generated Airy beam into space.

[0021] The signal generating unit 12 outputs the generated transmission data to the generating unit 11 .

[0022] The control unit 13 sets a phase pattern for generating an Airy beam in the beam generation unit 15. Furthermore, the control unit 13 adjusts the phase pattern so that the main lobes of the Airy beams generated in each generation unit 11 are directed toward the positions of the receiving units provided in the different receiving devices 20, and so that the side lobes of the Airy beam are not directed toward the positions of any of the receiving units. Specifically, the control unit 13 rotates the phase pattern of the lens provided in the beam generation unit 15, thereby controlling so that the side lobes of the Airy beam are not directed toward the positions of any of the receiving units.

[0023] As described above, the transmitting device 10 controls the side lobes of the Airy beams generated by each generating unit 11 so that they do not point toward the positions of any of the receiving units provided in the receiving device 20. This makes it possible to suppress interference between simultaneously transmitted Airy beams. As a result, the transmitting device 10 realizes spatial multiplexing transmission using Airy beams.

[0024] [Configuration of Receiving Device 20] Next, the configuration of the receiving device 20 will be described. The receiving device 20 includes N receiving units 21-1 to 21-N and a signal demodulation unit 22. The receiving units 21-1 to 21-N are arranged in parallel so as to face each generating unit 11 included in the transmitting device 10. The receiving units 21-1 to 21-N are arranged in different positions from each other. The receiving units 21-1 to 21-N receive radio waves transmitted from each generating unit 11 of the transmitting device 10 and detect the intensity of the received radio waves. The signal demodulation unit 22 calculates the distribution of Airy beams based on the intensity of the radio waves detected by each receiving unit 21 and performs demodulation processing.

[0025] 2 is a side view of an example of transmission by the transmitting device 10 according to the first embodiment. As shown in FIG. 2, in the transmitting device 10, N generating units 11 are arranged in parallel (in a line in the Y direction). That is, in the transmitting device 10, N combinations of carrier wave generating units 14, phase setting lenses 151, and Fourier lenses 152 for generating one Airy beam are arranged in parallel (in a line in the Y direction). Similarly, in the receiving device 20, N receiving units 21 are arranged in parallel (in a line in the Y direction).

[0026] In this situation, the control unit 13 adjusts the phase pattern of the phase setting lens 151 by rotating it so that the side lobes of the Airy beams generated by each generator 11 are oriented in the Z-axis direction (the direction of gravity). This makes it possible to suppress interference between multiple Airy beams. Each receiver 21 included in the receiving device 20 can then receive the Airy beam generated by the corresponding generator 11.

[0027] 3 is a diagram showing an example of transmission from the transmitting device 10 in the first embodiment as viewed from above. In FIG. 3, inf1 to infN represent the reception intensity distribution when the transmitting device 10 is viewed from the receiving device 20. The transmitting device 10 can achieve spatial multiplexing with no or low interference by adjusting the direction of the Airy beam generated by each generating unit 11 so that the main lobe is positioned at the position of each receiving unit 21 provided in the receiving device 20.

[0028] 3, the control unit 13 adjusts the main lobe of the Airy beam generated by the carrier wave generation unit 14-1, phase setting lens 151-1, and Fourier lens 152-1 that constitute the generation unit 11 so that it comes to the position of the receiving unit 21-1. Similarly, the control unit 13 adjusts the main lobe of the Airy beam generated by the carrier wave generation unit 14-N, phase setting lens 151-N, and Fourier lens 152-N that constitute the generation unit 11 so that it comes to the position of the receiving unit 21-N.

[0029] As in FIG. 2, the control unit 13 adjusts the phase pattern of the phase setting lens 151 by rotating it so that the side lobes of the Airy beams generated by each generation unit 11 are oriented in the Z-axis direction.

[0030] According to the communication system 100 configured as described above, the transmitting device 10 generates a plurality of Airy beams adjusted so that the main lobes of each Airy beam are directed toward the positions of different receiving units 21 and the side lobes of each Airy beam are not directed toward the positions of any of the receiving units 21, and is equipped with a plurality of beam generating units 15 that transmit transmission data using the generated Airy beams.

[0031] As a result, no interference occurs between the multiple Airy beams generated by the transmitting device 10, or even if interference occurs, the interference is so small that it has no impact. Therefore, the receiving device 20 can perform reception processing with fewer computational resources than demodulation processing performed using a normal MIMO spatial multiplexing method. Therefore, spatial multiplexing communication can be performed while reducing the signal processing load on the communication device.

[0032] Second Embodiment In the first embodiment, a configuration was shown in which N generating units in a transmitting device and N receiving units in a receiving device are provided in parallel in one stage. In contrast, by providing N generating units in a transmitting device and N receiving units in a receiving device in multiple stages, communication with a larger capacity becomes possible. Therefore, in the second embodiment, a configuration in which N generating units in a transmitting device and N receiving units in a receiving device are provided in multiple stages will be described.

[0033] 4 is a diagram showing an example of the configuration of a communication system 100a according to the second embodiment. The communication system 100a includes a transmitting device 10a and a receiving device 20a. The transmitting device 10a and the receiving device 20a perform wireless communication using a high frequency band.

[0034] [Configuration of Transmitting Device 10a] The transmitting device 10a includes a plurality of generating units 11, a signal generating unit 12 (not shown), and a control unit 13 (not shown). The transmitting device 10a has a configuration different from that of the transmitting device 10 in that the transmitting device 10a includes a plurality of stages of N generating units 11 as the plurality of generating units 11. Note that in Fig. 4, the signal generating units 12 and the control unit 13 included in the transmitting device 10a are omitted.

[0035] As shown in FIG. 4, the transmitting device 10a includes generating units 11-1-1 to 11-1-N as a first-stage generating unit group. Furthermore, the transmitting device 10a includes generating units 11-2-1 to 11-2-N as a second-stage generating unit group. The operations performed by each generating unit 11 are the same as those in the first embodiment. Note that although the transmitting device 10a is shown as including two stages of generating unit groups, the transmitting device 10a may include three or more stages of generating unit groups.

[0036] The control unit 13 of the transmitting device 10a causes each generating unit 11 to generate a plurality of Airy beams so that the received signals received by each of the two stages of receiving units 21 provided in the receiving device 20a are above a threshold value due to interference.

[0037] [Configuration of Receiving Device 20a] The receiving device 20a includes a plurality of receiving units 21 and a signal demodulation unit 22 (not shown). The receiving device 20a has a configuration different from that of the receiving device 20 in that the receiving device 20a includes N receiving units 21 in multiple stages as the plurality of receiving units 21. Note that the signal demodulation unit 22 included in the receiving device 20a is not shown in FIG. 4.

[0038] As shown in Fig. 4, the receiving device 20a includes receiving units 21-1-1 to 21-1-N as a first-stage receiving unit group. Furthermore, the receiving device 20a includes receiving units 21-2-1 to 21-2-N as a second-stage receiving unit group. The operation performed by each receiving unit 21 is the same as in the first embodiment. Note that although the receiving device 20a is shown as including two stages of receiving unit groups, the receiving device 20a may include three or more stages of receiving unit groups.

[0039] 4, in the transmitting device 10a, N generating units 11 are arranged in parallel (in a line in the Y direction) in two stages. That is, in the transmitting device 10a, N combinations of carrier wave generating units 14, phase setting lenses 151, and Fourier lenses 152 for generating one Airy beam are arranged in parallel (in a line in the Y direction) in two stages. Similarly, in the receiving device 20a, N receiving units 21 are arranged in parallel (in a line in the Y direction) in two stages.

[0040] In this situation, the control unit 13 adjusts the phase pattern of the phase setting lens 151 by rotating it so that the side lobes of the Airy beams generated by the generators 11-1-1 to 11-1-N included in the first-stage generator group are oriented in the +Z-axis direction. Furthermore, the control unit 13 adjusts the phase pattern of the phase setting lens 151 by rotating it so that the side lobes of the Airy beams generated by the generators 11-2-1 to 11-2-N included in the second-stage generator group are oriented in the -Z-axis direction. In this way, the control unit 13 adjusts the phase pattern of the phase setting lens 151 by rotating it so that the side lobes of the Airy beams generated by the generators 11-1-1 to 11-1-N included in the first-stage generator group and the generators 11-2-1 to 11-2-N included in the second-stage generator group are oriented in a direction that minimizes interference with the side lobes of other Airy beams. This makes it possible to suppress interference between multiple Airy beams. Each receiving unit 21 included in the receiving device 20 can receive the Airy beam generated by the corresponding generating unit 11.

[0041] 5 is a diagram showing an example of transmission from the transmitter 10a in the second embodiment, viewed from above. In FIG. 5, inf1-1 to inf1-N and inf2-1 to inf2-N represent the reception intensity distribution when the transmitter 10a is viewed from the receiver 20a. For example, inf1-1 to inf1-N represent the reception intensity distribution when the transmitter 10a is viewed from the first-stage group of receivers provided in the receiver 20a. For example, inf2-1 to inf2-N represent the reception intensity distribution when the transmitter 10a is viewed from the second-stage group of receivers provided in the receiver 20a.

[0042] The transmitting device 10a can achieve interference-free or low-interference spatial multiplexing by adjusting the direction of the Airy beam generated by each generating unit 11 so that the main lobe is located at the position of each receiving unit 21 included in the receiving device 20a. In the example shown in Figure 5, the control unit 13 adjusts the main lobe of the Airy beam generated by the carrier wave generating unit 14-1, phase setting lens 151-1, and Fourier lens 152-1 constituting the generating unit 11 so that it is located at the position of the receiving unit 21-1. Similarly, the control unit 13 adjusts the main lobe of the Airy beam generated by the carrier wave generating unit 14-N, phase setting lens 151-N, and Fourier lens 152-N constituting the generating unit 11 so that it is located at the position of the receiving unit 21-N.

[0043] 4, the control unit 13 adjusts the phase pattern of the phase setting lens 151 by rotating it so that the side lobes of the Airy beams generated by each of the first-stage generators 11 are oriented in the +Z-axis direction. Similarly to FIG. 4, the control unit 13 adjusts the phase pattern of the phase setting lens 151 by rotating it so that the side lobes of the Airy beams generated by each of the second-stage generators 11 are oriented in the −Z-axis direction.

[0044] According to the communication system 100a configured as above, it is possible to obtain the same effects as those of the first embodiment.

[0045] Furthermore, in the communication system 100a, the generator 11 and receiver 21 are arranged in an array structure in the transmitter 10a and receiver 20a. Even in this configuration, interference between Airy beams can be suppressed by rotating the phase pattern of the one-phase setting lens 151. Therefore, spatial multiplexing transmission with a larger capacity than that of the first embodiment is possible.

[0046] A part (e.g., the control unit 13) or all of the transmitting device 10, 10a in the above-described embodiment may be realized by a computer. In this case, a program for realizing this function may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read and executed by a computer system. Note that the term "computer system" here includes hardware such as an OS (Operating System) and peripheral devices.

[0047] Furthermore, the term "computer-readable recording medium" refers to portable media such as flexible disks, magneto-optical disks, ROMs (Read Only Memory), and CD-ROMs, as well as storage devices such as hard disks built into computer systems. Furthermore, the term "computer-readable recording medium" may also include devices that dynamically store programs for a short period of time, such as communication lines used when transmitting programs over networks like the Internet or communication lines like telephone lines, and devices that store programs for a fixed period of time, such as volatile memory within the computer systems that serve as servers or clients in such cases. The above programs may also be recorded on computer-readable recording media. Examples of computer-readable recording media include portable media such as flexible disks, magneto-optical disks, ROMs, CD-ROMs, and semiconductor storage devices (e.g., solid-state drives (SSDs)), as well as storage devices such as hard disks and semiconductor storage devices built into computer systems. The above programs may also be transmitted via telecommunications lines.

[0048] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention.

[0049] The present invention can be applied to wireless communication technology using high frequency bands.

[0050] 10, 10a... Transmitting device, 11, 11-1 to 11-N... Generator, 12... Signal generator, 13... Control unit, 14, 14-1 to 14-N, 14-1-1 to 14-1-N, 14-2-1 to 14-2-N... Carrier wave generator, 15, 15-1 to 15-N, 15-1-1 to 15-1-N, 15-2-1 to 15-2-N... Beam generator, 20, 20a... Receiving device, 21, 21-1 to 21-N, 21-1-1 to 21-1-N, 21-2-1 to 21-2-N... Receiving unit, 22... Signal demodulator, 100, 100a... Communication system, 151, 151-1 to 151-N, 151-1-1 to 151-1-N, 151-2-1 to 151-2-N...phase setting lenses, 152, 152-1 to 152-N, 152-1-1 to 152-1-N, 152-2-1 to 152-2-N...Fourier lenses

Claims

1. A transmitting device that transmits signals to a receiving device equipped with multiple receiving antennas arranged at different positions, comprising: multiple beam generating units that generate multiple Airy beams, which have the property of causing radio waves to be spatially asymmetric, and are adjusted so that the main lobes of each Airy beam are directed toward the positions of different receiving antennas and the side lobes of each Airy beam are not directed toward the positions of any of the receiving antennas; and that transmits transmission data using the multiple Airy beams that have been generated.

2. The transmitting device according to claim 1, wherein the plurality of beam generating units are configured by arranging in parallel a combination of a plurality of lenses for generating the Airy beams.

3. The transmitting device described in claim 2, wherein the multiple beam generating units are configured by arranging the multiple lens combinations in parallel in at least two stages, and generate the multiple Airy beams in which the side lobes of each Airy beam generated by the multiple lens combinations arranged in parallel in the first stage are different from the side lobes of each Airy beam generated by the multiple lens combinations arranged in parallel in the second stage.

4. A transmitting device as described in claim 2 or 3, further comprising a control unit that controls the direction of the side lobes of each of the multiple Airy beams generated in the multiple beam generating units by rotating the phase patterns of some of the multiple lenses.

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