Transmission device, communication system, and communication method

Abstract

This transmission device that communicates with a reception device comprises: a transmission antenna that is installed at a predetermined angle in the transmission device and transmits a transmission signal to the reception device; a beam generation unit that generates, for the transmission signal transmitted by the transmission antenna, a circular Airy beam so as to have a predetermined focal length; and a control unit that controls at least one of the predetermined focal length and the predetermined angle on the basis of the reception intensity of the circular Airy beam fed back from the reception device.

Description

Transmitting device, communication system, and communication method

[0001] The present invention relates to a transmitting device, a communication system, and a communication method.

[0002] In wireless transmission, in high-frequency bands such as millimeter waves and sub-terahertz waves, radio waves tend to propagate in a straight line, making diffraction difficult. Therefore, communication becomes difficult due to obstacles and other factors. To eliminate interference, it is necessary to perform digital signal processing such as beamforming, or to control the phase and amplitude distribution of radio waves to form beams without causing interference. Beamforming increases the amount of signal processing. Furthermore, when controlling the phase and amplitude distribution, it is difficult to avoid obstacles using conventional lens control. Therefore, it is necessary to control the phase and amplitude distribution so that communication can be established and high-quality communication can be achieved even when there are obstacles between the transmitter and receiver. Non-Patent Document 1 discloses an Airy beam, which has side lobes that exist only in specific regions and have no intensity in other regions.

[0003] R. Kadlimatti, “Millimeter-Wave Nondiffracting Circular Airy OAM Beams”, IEEE Trans. on Antennas and Propagation, Vol. 67, No. 1, pp. 260-269 (2019).

[0004] The technology in Non-Patent Document 1 discloses an Airy Beam, and so even if an obstacle exists between the transmitting device and the receiving device, it is believed that the transmitting device can transmit a signal to a receiving device located behind the obstacle. However, with the technology disclosed in Non-Patent Document 1, if an obstacle exists between the transmitting device and the receiving device and the reception quality at the receiving device is poor, it is not possible to improve the reception quality at the receiving device.

[0005] In view of the above circumstances, the present invention aims to provide a technology that can improve the reception quality of a receiving device even when an obstacle exists between a transmitting device and a receiving device and the reception quality of the receiving device is poor.

[0006] One aspect of the present invention is a communication system comprising a transmitting device and a receiving device, wherein the transmitting device comprises a transmitting antenna installed at a predetermined angle to the transmitting device and transmitting a transmission signal to the receiving device, and a beam generating unit that generates a circular Airy beam for the transmission signal transmitted by the transmitting antenna so that the transmission signal has a predetermined focal length, the receiving device comprises a beam receiving unit that receives the circular Airy beam generated by the beam generating unit, a receiving strength measuring unit that measures the receiving strength of the Airy beam received by the beam receiving unit, and a feedback transmitting unit that feeds back the receiving strength measured by the receiving strength measuring unit to the transmitting device, and the transmitting device further comprises a control unit that controls at least one of the predetermined focal length and the predetermined angle based on the receiving strength fed back from the feedback transmitting unit.

[0007] Another aspect of the present invention is a transmitting device that communicates with a receiving device, comprising: a transmitting antenna that is installed at a predetermined angle to the transmitting device and transmits a transmission signal to the receiving device; a beam generating unit that generates a circular Airy beam so that the transmission signal transmitted by the transmitting antenna has a predetermined focal length; and a control unit that controls at least one of the predetermined focal length and the predetermined angle based on the reception strength of the circular Airy beam that is fed back from the receiving device.

[0008] Yet another aspect of the present invention is a communication method used in a communication system comprising a transmitting device and a receiving device, comprising: a transmitting process in which the transmitting device transmits a transmission signal to the receiving device from a transmitting antenna installed at a predetermined angle on the transmitting device; a beam generation process in which the transmitting device generates a circular Airy beam for the transmission signal generated in the transmitting process so that the circular Airy beam has a predetermined focal length; a beam reception process in which the receiving device receives the circular Airy beam generated in the beam generation process; a reception intensity measurement process in which the receiving device measures the reception intensity of the Airy beam received in the beam reception process; a feedback process in which the receiving device feeds back the reception intensity measured in the intensity measurement process; and the transmitting device controls at least one of the predetermined focal length and the predetermined angle based on the reception intensity fed back in the feedback process.

[0009] According to the present invention, even when an obstacle exists between the transmitting device and the receiving device and the receiving quality at the receiving device is poor, the receiving quality at the receiving device can be improved.

[0010] FIG. 1 is a schematic configuration diagram of a communication system according to an embodiment of the present invention. FIG. 2 is a sequence diagram showing a processing flow of the communication system according to the embodiment of the present invention. FIG. 3 is a schematic diagram explaining a communication system according to an embodiment of the present invention. FIG. 4 is a graph showing an example of characteristics when an embodiment of the present invention is used. FIG. 5 is a graph showing another example of characteristics when an embodiment of the present invention is used. FIG. 6 is a first diagram showing an overview of the operation of a communication system according to an embodiment of the present invention. FIG. 7 is a second diagram showing an overview of the operation of a communication system according to an embodiment of the present invention. FIG. 8 is a third diagram showing an overview of the operation of a communication system according to an embodiment of the present invention.

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a schematic diagram of a communication system 100 according to an embodiment of the present invention. The communication system 100 includes a transmitting device 10 and a receiving device 20. The transmitting device 10 includes a transmitting device control unit 11, a transmitting device storage unit 12, a transmission signal generation unit 13, a transmitting antenna 14, and a beam generation unit 15.

[0012] The transmitting device control unit 11 includes a CPU (Central Processing Unit) and is connected to the transmitting device storage unit 12, the transmission signal generation unit 13, the transmitting antenna 14, and the beam generation unit 15. The transmitting device control unit 11 controls each unit of the transmitting device 10.

[0013] The transmitting device control unit 11 includes a focal length control unit 111 and an angle control unit 112. The focal length control unit 111 controls the focal length of the circular Airy beam generated by the beam generation unit 15 based on information fed back from the receiving device 20. The angle control unit 112 controls the angles of the transmitting antenna 14 and the beam generation unit 15 installed in the transmitting device 10 based on information fed back from the receiving device 20. The transmitting device storage unit 12 is connected to the transmitting device control unit 11. The transmitting device storage unit 12 includes storage devices such as a memory and an HDD (Hard Disk Drive), and stores data necessary for operating the transmitting device 10, data to be transmitted to the receiving device 20, etc.

[0014] The transmission signal generation unit 13 is connected to the transmission device control unit 11 and the transmission antenna 14. The transmission signal generation unit 13 generates a transmission signal by performing transmission processing such as modulation and encoding on data to be transmitted from the transmission device 10 to the receiving device 20. The transmission antenna 14 is connected to the angle control unit 112, the transmission signal generation unit 13, and the beam generation unit 15. The transmission antenna 14 transmits the transmission signal generated by the transmission signal generation unit 13 to the receiving device 20. The beam generation unit 15 is connected to the focal length control unit 111, the angle control unit 112, and the transmission antenna 14. Based on the control of the focal length control unit 111, the beam generation unit 15 generates a circular Airy beam having a predetermined focal length zf for the transmission signal transmitted from the transmission antenna 14. The beam generation unit 15 has a phase modulation lens 151 and a Fourier transform lens 152, which will be described later in FIG. 3, and adjusts the positional relationship between the phase modulation lens 151 and the Fourier transform lens 152 to adjust the focal length zf. The transmitting antenna 14 and the beam generating unit 15 are installed at a predetermined angle in the transmitting device 10 , and the angle can be changed based on the control of the angle control unit 112 .

[0015] An Airy beam has the property that side lobes exist only in specific regions and have no intensity in other regions. Furthermore, a circular Airy beam (CAB) in which this Airy beam distribution is concentric has a distribution with no intensity near the central axis extending up to a specific distance. Furthermore, even if there is an obstacle in the part of the circular Airy beam where there is no intensity, the circular Airy beam has the property of being self-repairing, so that it can propagate while maintaining the circular Airy beam. A circular Airy beam is a beam that has an Airy beam distribution with a radius r of the main lobe so that the area near the center of the propagation axis becomes null. ０ The circular Airy beam has the property that its intensity increases sharply at a specific distance zf. The circular Airy beam has a phase distribution φ １ (r) can be generated by giving b ０ is the phase constant. ０is the radius of the main lobe. r is the distance from the central axis. k is a value expressed by the formula k = λ / 2π. f １ is the focal length of the lens.

[0016]

[0017] The following equation (2) holds true:

[0018]

[0019] Therefore, a variable phase plate is used as the beam generator 15, ０ and r ０ By controlling the distance zf, it is possible to control the distance zf according to the distance to the receiving device 20.

[0020] 1 includes a receiving device control unit 21, a receiving device storage unit 22, a receiving antenna 23, a beam receiving unit 24, a reception intensity measurement unit 25, and a feedback transmission unit 26. The receiving device control unit 21 includes a CPU (Central Processing Unit) and the like. The receiving device control unit 21 is connected to the receiving device storage unit 22, the beam receiving unit 24, the reception intensity measurement unit 25, and the feedback transmission unit 26. The receiving device control unit 21 controls each unit of the receiving device 20.

[0021] The receiving device storage unit 22 is connected to the receiving device control unit 21. The receiving device storage unit 22 includes a storage device such as a memory or a hard disk drive (HDD), and stores data necessary for operating the receiving device 20, data transmitted from the transmitting device 10, etc. The receiving antenna 23 is connected to the beam receiving unit 24. The receiving antenna 23 receives the circular Airy beam transmitted from the transmitting device 10 and outputs it to the beam receiving unit 24.

[0022] The beam receiving unit 24 is connected to the receiving device control unit 21, the receiving antenna 23, and the receiving intensity measurement unit 25. The beam receiving unit 24 performs decoding processing, demodulation processing, etc. on the signal output from the receiving antenna 23. The receiving intensity measurement unit 25 is connected to the receiving device control unit 21 and the beam receiving unit 24. The receiving intensity measurement unit 25 measures the receiving intensity of the circular Airy beam transmitted from the transmitting device 10 and received by the receiving device 20.

[0023] The feedback transmission unit 26 is connected to the receiving device control unit 21. The feedback transmission unit 26 acquires the reception strength measured by the reception strength measurement unit 25 via the receiving device control unit 21 and transmits it to the transmission device 10.

[0024] 2 is a sequence diagram showing the processing flow of the communication system 100 according to an embodiment of the present invention. First, the transmission signal generation unit 13 of the transmitting device 10 generates a transmission signal to be transmitted to the receiving device 20, and transmits the signal from the transmitting antenna 14 installed at a predetermined angle on the transmitting device 10 (step S11). Next, the beam generation unit 15 of the transmitting device 10 generates a circular Airy beam for the transmission signal transmitted in step S11 so as to have a predetermined focal length (step S12).

[0025] The beam receiving unit 24 of the receiving device 20 receives the circular Airy beam transmitted from the transmitting device 10 in step S12 via the receiving antenna 23 (step S13). Next, the reception intensity measuring unit 25 of the receiving device 20 measures the reception intensity of the circular Airy beam received by the beam receiving unit 24 in step S13 (step S14). Next, the feedback transmitting unit 26 of the receiving device 20 transmits information about the reception intensity measured in step S14 to the transmitting device 10 (step S15).

[0026] In step S15, the transmitter control unit 11 of the transmitter 10 acquires information on the reception strength fed back from the receiver 20 (step S16). Next, the transmitter control unit 11 of the transmitter 10 controls at least one of the focal length of the circular Airy beam and the angle of the transmitting antenna based on the reception strength fed back from the receiver 20 (step S17). Specifically, the angle control unit 112 included in the transmitter control unit 11 controls the angle of the transmitting antenna 14 and the beam generation unit 15 installed in the transmitter 10 based on the feedback information on the reception strength periodically transmitted from the receiver 20 so as to maximize the reception strength at the receiver 20. Alternatively, the focal length control unit 111 included in the transmitter control unit 11 controls the focal length of the circular Airy beam generated by the beam generation unit 15 based on the feedback information on the reception strength periodically transmitted from the receiver 20 so as to maximize the reception strength at the receiver 20.

[0027] 2, the case where at least one of the control by the focal length control unit 111 and the control by the angle control unit 112 is performed is described, but both controls may be performed. Because the width of the circular Airy beam generated by the beam generation unit 15 is narrow, when both the control by the focal length control unit 111 and the control by the angle control unit 112 are performed, it is preferable that the angle control unit 112 first controls the angles of the transmitting antenna 14 and the beam generation unit 15 so as to increase the received power at the receiving device 20, and then the focal length control unit 111 controls the focal length.

[0028] Fig. 3 is a schematic diagram illustrating a communication system 100 according to an embodiment of the present invention. Fig. 3 illustrates a case in which a circular Airy beam is transmitted from a transmitting device 10 to a receiving device 20, and an obstacle X1 is present between the transmitting device 10 and the receiving device 20. Note that Fig. 3 omits the illustration of components of the transmitting device 10 shown in Fig. 1 other than the transmission signal generating unit 13, the transmitting antenna 14, and the beam generating unit 15. The circular Airy beam generated by the beam generating unit 15 included in the transmitting device 10 is adjusted to avoid the obstacle X1 by adjusting the positional relationship between the phase modulation lens 151 and the Fourier transform lens 152 included in the beam generating unit 15, and then the circular Airy beam is adjusted to a focal length z ｆ By controlling the signal strength, the receiving device 20 can maximize the receiving strength.

[0029]

[0030] FIG. 4 shows the transmission frequency of the transmitting device 10 according to the embodiment of the present invention, which is 140 GHz. ０ When b is 0.2 m ０ and Z ｆ 4 is a graph showing an example of the relationship between b ０ As the value of z increases, the value of z shown on the vertical axis ｆ decreases.

[0031] FIG. 5 shows a case where the transmission frequency is 140 GHz and b ０ When r is 40 ０ and Z ｆ 5 is a graph showing an example of the relationship between r ０ As the value of z increases, the value of z shown on the vertical axis ｆ will rise.

[0032] 6, 7, and 8 are diagrams showing an overview of the operation of a communication system according to an embodiment of the present invention. Note that, among the components of the transmitting device 10 shown in Fig. 1, components other than the transmission signal generating unit 13, the transmitting antenna 14, and the beam generating unit 15 are omitted from the illustration. In Fig. 6, the center of the circular Airy beam transmitted from the transmitting device 10 is shifted from the position of the receiving device 20.

[0033] However, in Fig. 7, the angles of the transmitting antenna 14 and the beam generating unit 15 installed in the transmitting device 10 are adjusted by the angle control unit 112 so that the center of the circular Airy beam transmitted from the transmitting device 10 faces the direction of the receiving device 20. Furthermore, in Fig. 8, the focal length of the circular Airy beam generated by the beam generating unit 15 of the transmitting device 10 is z ｆ The focal length control unit 111 controls the focal length so that the focal length becomes equal to or larger than the focal length of the transmitting device 10. By performing such processing, the communication system 100 according to the present embodiment can improve the reception quality at the receiving device 20 even when an obstacle X1 exists between the transmitting device 10 and the receiving device 20 and the reception quality at the receiving device 20 is poor.

[0034] At least some of the functions of the components of the transmitting device 10 and the receiving device 20 in the above-described embodiments may be implemented by a computer. In this case, a program for implementing these functions may be recorded on a computer-readable recording medium, and the program may be loaded into a computer system and executed. The term "computer system" as used herein includes hardware such as an operating system (OS) and peripheral devices. The term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, read-only memories (ROMs), and CD-ROMs, as well as storage devices such as hard disks built into computer systems. The term "computer-readable recording medium" may also include media that dynamically store programs for a short period of time, such as communication lines used when transmitting programs via networks such as the Internet or telephone lines, or media that store programs for a fixed period of time, such as volatile memory within the computer systems that serve as servers or clients. The program may be designed to implement some of the above-described functions, or may be capable of implementing the above-described functions in combination with programs already stored in the computer system, or may be implemented using a programmable logic device such as an FPGA.

[0035] 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.

[0036] The present invention can be applied to a transmitting device, a communication system, a communication method, etc., in which it is necessary to improve the reception quality at a receiving device even when an obstacle exists between the transmitting device and the receiving device and the reception quality at the receiving device is poor.

[0037] REFERENCE SIGNS LIST 10... Transmitting device, 11... Transmitting device control unit, 12... Transmitting device storage unit, 13... Transmission signal generation unit, 14... Transmitting antenna, 15... Beam generation unit, 20... Receiving device, 21... Receiving device control unit, 22... Receiving device storage unit, 23... Receiving antenna, 24... Beam reception unit, 25... Receiving intensity measurement unit, 26... Feedback transmission unit, 100... Communication system, 111... Focal length control unit, 112... Angle control unit

Claims

1. A communication system comprising a transmitting device and a receiving device, wherein the transmitting device comprises: a transmitting antenna installed at a predetermined angle to the transmitting device and transmitting a transmission signal to the receiving device; and a beam generating unit that generates a circular Airy beam for the transmission signal transmitted by the transmitting antenna so that the transmission signal has a predetermined focal length; the receiving device comprises: a beam receiving unit that receives the circular Airy beam generated by the beam generating unit; a reception strength measuring unit that measures the reception strength of the Airy beam received by the beam receiving unit; and a feedback transmitting unit that feeds back the reception strength measured by the reception strength measuring unit to the transmitting device; and the transmitting device further comprises a control unit that controls at least one of the predetermined focal length and the predetermined angle based on the reception strength fed back from the feedback transmitting unit.

2. The communication system according to claim 1, wherein the control unit controls at least one of the predetermined focal length and the predetermined angle so that the reception strength fed back from the feedback transmission unit is maximized.

3. The communication system according to claim 1, wherein the control unit controls the predetermined angle before controlling the predetermined focal length.

4. The communication system according to claim 1, wherein the beam generating unit generates the circular Airy beam having the predetermined focal length using a variable phase plate.

5. A transmitting device that communicates with a receiving device, comprising: a transmitting antenna that is installed at a predetermined angle to the transmitting device and transmits a transmission signal to the receiving device; a beam generating unit that generates a circular Airy beam so that the transmission signal transmitted by the transmitting antenna has a predetermined focal length; and a control unit that controls at least one of the predetermined focal length and the predetermined angle based on the reception strength of the circular Airy beam that is fed back from the receiving device.

6. A communication method used in a communication system having a transmitting device and a receiving device, comprising: a transmitting step in which the transmitting device transmits a transmission signal to the receiving device from a transmitting antenna installed at a predetermined angle on the transmitting device; a beam generation step in which the transmitting device generates a circular Airy beam for the transmission signal generated in the transmitting step so that the circular Airy beam has a predetermined focal length; a beam reception step in which the receiving device receives the circular Airy beam generated in the beam generation step; a reception intensity measurement step in which the receiving device measures the reception intensity of the Airy beam received in the beam reception step; a feedback step in which the receiving device feeds back the reception intensity measured in the intensity measurement step; and a communication method in which the transmitting device controls at least one of the predetermined focal length and the predetermined angle based on the reception intensity fed back in the feedback step.

Images