Estimation device and estimation method

Abstract

To provide an estimation apparatus and estimation method that can estimate the beam direction and beam width of a beam transmitted from a base station antenna without performing a pre-calculation using a map.SOLUTION: An estimation apparatus 1 includes: an antenna device 10 that has multiple antenna elements Rx1 to RxN and receives multiple beams of a transmission signal transmitted from a base station antenna Tx as a reception signal at multiple measurement points in a measurement area; a position orientation acquisition device 13 that acquires the position and orientation of each measurement point where the antenna device 10 is arranged; a data recording device 14 that records the data of the reception signal received by the antenna device 10 arranged at each measurement point and the data of the position and orientation of each measurement point acquired by the position orientation acquisition device 13; and a signal processing device 20 that estimates the beam direction and beam width of each beam from the data of the reception signal and the data of the position and orientation of each measurement point recorded in the data recording device 14.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an estimation device and an estimation method for estimating a beam shape of a radio wave transmitted from a base station. [Background technology]

[0002] In recent years, the fifth generation mobile communication system has been put into operation as a mobile communication system, and the number of compatible mobile terminals is increasing. Among them, millimeter waves, which have high frequencies that can realize ultra-high speed communication, are also used. Millimeter wave radio waves are characterized by strong directivity, vulnerability to obstruction, and large distance attenuation. Therefore, in order to obtain sufficient power for communication with mobile terminals, the antenna beam formed by the base station is a complex one consisting of multiple beams with narrow beam widths. Moreover, information on the beam shape of the antenna beam, such as the beam direction and beam width, is not disclosed because it differs depending on the base station and to ensure confidentiality. However, when a base station is installed, information on the antenna beams of base stations existing in the vicinity is necessary to avoid interference with existing systems.

[0003] In addition, in systems that use radio waves with frequencies lower than millimeter waves, communication is possible even in the shadow of a building due to the diffraction of radio waves, but because millimeter waves have a high degree of directivity, if they are blocked by a building the communication area is limited. For this reason, technology is being developed to install reflectors, etc., with the aim of expanding the communication area. To calculate the installation position of the reflector, it is necessary to understand parameters such as the beam direction and beam width of the existing base station antenna.

[0004] A known method for estimating antenna beam parameters is to construct a radio wave map, determine whether the observation data is line-of-sight or non-line-of-sight using a Fresnel zone and a height map, select line-of-sight measurement data, and perform weighted averaging to estimate the parameters (see, for example, Non-Patent Document 1).Another known estimation method is to use the correlation coefficient between the received power distribution measured by placing a wireless sensor in the field and the estimated power distribution obtained by calculation (see, for example, Non-Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Non-Patent Document 1] Shogo Matsuo, Hirofumi Nakajo, Nao Miyamoto, Takeo Fujii, Kenji Wakafuji, "A study on millimeter wave beam pattern estimation method based on radio wave map and multi-beam antenna model," IEICE Technical Report RCS2022-120 (August 2022) [Non-Patent Document 2] Yoshio Kunisawa, Hiroki Matsuno, Takahiro Hayashi, and Yoshiaki Amano, "A Study on Estimation of Direction of Directional Antenna for Dynamic Spectrum Sharing," IEICE General Conference 2020, B-17-4, March 2020 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the conventional methods disclosed in Non-Patent Documents 1 and 2 require pre-calculation using a 3D map, etc., for each area to be estimated. Although the 3D map, etc. required for pre-calculation may be updated as needed, it is assumed that the data may differ from that during field measurement, which may result in a large error.

[0007] The present invention has been made to solve such conventional problems, and aims to provide an estimation device and an estimation method that can estimate the beam direction and beam width of a beam transmitted from a base station antenna without performing pre-calculation using a map. [Means for solving the problem]

[0008] In order to solve the above problem, an estimation device according to the present invention includes an antenna device having a plurality of antenna elements, the antenna device receiving a plurality of beams of a transmission signal transmitted from a base station antenna as received signals by the plurality of antenna elements at a plurality of measurement points within a measurement area, a position and orientation acquisition device acquiring a position and orientation of each of the measurement points at which the antenna device is disposed, a data recording device recording data of the received signal received by the antenna device disposed at each of the measurement points and data of the position and orientation of each of the measurement points acquired by the position and orientation acquisition device, and a signal processing device estimating a beam direction and beam width of each of the beams from the data of the received signal recorded in the data recording device and the data of the position and orientation of each of the measurement points, the signal processing device including a reference signal extraction unit extracting a reference signal included in the received signal, a channel response generation unit generating a channel response of each of the beams from a known reference signal included in the transmission signal and the reference signal extracted from the received signal by the reference signal extraction unit, and a direction of arrival estimation unit that estimates a direction of arrival in which each of the beams has the highest power level for each of the measurement points based on a channel response of the beam; a base station position estimation unit that estimates a position of the base station antenna using the direction of arrival estimated by the direction of arrival estimation unit; a received power calculation unit that calculates received power of the plurality of antenna elements at each of the measurement points; a power distribution calculation unit that calculates a maximum position that is a position of the maximum value of the power distribution of each of the beams in the measurement area and a beam boundary that is a position 3 dB lower than the maximum value, based on the position of each of the measurement points, the position of the base station antenna estimated by the base station position estimation unit, and the received power calculated by the received power calculation unit; a beam direction estimation unit that estimates a beam direction of each of the beams based on the position of the base station antenna estimated by the base station position estimation unit and the maximum position of each of the beams calculated by the power distribution calculation unit; and a beam width estimation unit that estimates a beam width of the beam based on the beam boundary of each of the beams calculated by the power distribution calculation unit.

[0009] With this configuration, the estimation device of the present invention can estimate the direction of arrival of the direct wave of the transmission signal from the base station antenna, and can therefore estimate the beam direction and beam width of the beam transmitted from the base station antenna without performing pre-calculation using a map.

[0010] Furthermore, an estimation method according to the present invention is an estimation method using an estimation device including: an antenna device having a plurality of antenna elements, the plurality of beams of a transmission signal transmitted from a base station antenna being received as reception signals by the plurality of antenna elements at a plurality of measurement points within a measurement area; a position and orientation acquisition device acquiring a position and orientation of each of the measurement points at which the antenna devices are disposed; a data recording device recording data of the reception signals received by the antenna devices disposed at each of the measurement points and data of the position and orientation of each of the measurement points acquired by the position and orientation acquisition device; and a signal processing device estimating a beam direction and beam width of each of the beams from the data of the reception signals recorded in the data recording device and the data of the position and orientation of each of the measurement points, the estimation method including the steps of: a reference signal extraction step of extracting a reference signal included in the reception signal; a channel response generation step of generating a channel response of each of the beams from a known reference signal included in the transmission signal and the reference signal extracted from the reception signal by the reference signal extraction step; a direction of arrival estimation step of estimating, for each of the measurement points, the direction of arrival with the highest power level of each of the beams based on the direction of arrival estimation step; a base station position estimation step of estimating a position of the base station antenna using the direction of arrival estimated by the direction of arrival estimation step; a received power calculation step of calculating received power of the plurality of antenna elements at each of the measurement points; a power distribution calculation step of calculating, based on the position of each of the measurement points, the position of the base station antenna estimated by the base station position estimation step, and the received power calculated by the received power calculation step, a maximum position which is a position of the maximum value of the power distribution of each of the beams in the measurement area and a beam boundary which is a position 3 dB lower than the maximum value; a beam direction estimation step of estimating a beam direction of each of the beams based on the position of the base station antenna estimated by the base station position estimation step and the maximum position of each of the beams calculated by the power distribution calculation step; and a beam width estimation step of estimating a beam width of the beam based on the beam boundary of each of the beams calculated by the power distribution calculation step. Effect of the Invention

[0011] The present invention provides an estimation device and an estimation method capable of estimating the beam direction and beam width of a beam transmitted from a base station antenna without performing pre-calculation using a map. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram illustrating a configuration of an estimation device according to an embodiment of the present invention. [Diagram 2] 1A shows an example in which the antenna device and the position and orientation acquisition device in an estimation device according to an embodiment of the present invention are configured as an integrated device, and FIG. 1B shows an example in which the antenna device, the position and orientation acquisition device, and the data recording device in an estimation device according to an embodiment of the present invention are configured as an integrated device. [Diagram 3] 1A and 1B are schematic diagrams showing the configuration of an antenna device, in which (a) is a perspective view and (b) is a plan view. [Figure 4] FIG. 2 is a diagram showing an example of the positional relationship between a base station antenna and multiple measurement points. [Diagram 5] 1 is a block diagram showing a configuration of a signal processing device in an estimation device according to an embodiment of the present invention. [Figure 6] 1 is a diagram for explaining a method for estimating the position of a base station antenna by a signal processing device. [Figure 7] Graph (a) shows the maximum position and the position -3 dB from the maximum of the power distribution of the beam transmitted from the base station antenna, and graph (b) shows the elevation / depression angle θ of the beam of the transmitted signal. [Figure 8] 1 is a graph showing an example of fitting a beam transmitted from a base station antenna; [Figure 9] Graph (a) is a graph for explaining the horizontal beam width of a beam of a transmission signal, and graphs (b) and (c) are graphs for explaining the vertical beam width of a beam of a transmission signal. [Figure 10]11 is a graph showing an error between beam parameters obtained by a ray tracing simulation and the estimation results of the beam parameters obtained by the estimation device according to the embodiment of the present invention. [Figure 11] 4 is a flowchart for explaining a process of an estimation method using the estimation device according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an estimation device and an estimation method according to the present invention will be described with reference to the drawings.

[0014] 1, an estimation device 1 of this embodiment includes an antenna device 10, a position and orientation acquisition device 13, a data recording device 14, a signal processing device 20, a display device 40, and an operation device 41. Each device is connected to each other by wireless communication or wired communication.

[0015] 2(a) shows a configuration in which the antenna device 10 and the position / orientation acquisition device 13 are configured as an integrated device that can be loaded onto a drone or the like, the antenna device 10 and the position / orientation acquisition device 13 are each connected to a data recording device 14 via wireless communication, and the data recording device 14 and the signal processing device 20 are connected via wired communication. The data recording device 14 and the signal processing device 20 may be configured in a cloud server.

[0016] 2(b) shows a configuration in which the antenna device 10, the position and orientation acquisition device 13, and the data recording device 14 are configured as an integrated device that can be loaded onto a drone or the like, the antenna device 10 and the position and orientation acquisition device 13 are each connected to the data recording device 14 by wired communication, and the data recording device 14 and the signal processing device 20 are connected by wireless communication. The signal processing device 20 may be configured in a cloud server.

[0017] The antenna device 10 receives a plurality of beams of a transmission signal transmitted from a base station antenna Tx of a base station 100 at a plurality of measurement points 30 (see FIG. 4) within a measurement area MA. The antenna device 10 has a plurality of N antenna elements Rx1 to RxN that receive the transmission signal transmitted from the base station antenna Tx as a received signal, and a receiver 11 having the same number of receiving units 11-1 to 11-N as the plurality of N antenna elements Rx1 to RxN. Each of the antenna elements Rx1 to RxN is, for example, a planar antenna such as a microstrip antenna.

[0018] Each of the receiving units 11-1 to 11-N performs receiving processes such as amplification, frequency conversion, and analog-to-digital conversion on the received signal (wireless signal) received by the corresponding antenna element Rx1 to RxN. Note that the number of the receiving units 11-1 to 11-N may be less than the number of the antenna elements Rx1 to RxN. In that case, it is sufficient that the antenna elements Rx1 to RxN can be switched using a switch or the like to be connected to each of the receiving units 11-1 to 11-N.

[0019] 3(a) and (b) are schematic diagrams showing a configuration example of the antenna device 10. In the example of Fig. 3(a) and (b), N=8, and four antenna elements Rx1 to Rx4 are provided at height h1 and four antenna elements Rx5 to Rx8 are provided at height h2 on four side surfaces of a rectangular prism-shaped pillar 12.

[0020] As shown in Fig. 3(a), the set of four antenna elements Rx1 to Rx4 and the set of four antenna elements Rx5 to Rx8 are arranged so that they are spaced 0.5λ apart in the height direction. Also, as shown in Fig. 3(b), the four antenna elements Rx1 to Rx4 are arranged so that the centers of adjacent antenna elements are spaced 0.5λ apart in the horizontal direction. Similarly, the four antenna elements Rx5 to Rx8 are arranged so that the centers of adjacent antenna elements are spaced 0.5λ apart in the horizontal direction. Here, λ is the wavelength of the millimeter wave beam transmitted from the base station antenna Tx.

[0021] 4 shows an example of the positional relationship between the base station antenna Tx and the multiple measurement points 30. In the figure, a black circle indicates the position of the base station antenna Tx, and a white square indicates the position of each measurement point 30. For example, when the beam transmitted from the base station antenna Tx is a millimeter wave, the multiple measurement points 30 may be provided in a range of 100 m x 100 m that is assumed to be a communication area. The antenna device 10 is arranged such that, for example, the midpoint between the center position of the set of four antenna elements Rx1 to Rx4 and the center position of the set of four antenna elements Rx5 to Rx8 coincides with each measurement point 30.

[0022] The position and orientation acquisition device 13 is a device that acquires the position and orientation of each measurement point 30 where the antenna device 10 is arranged. The position and orientation acquisition device 13 is configured, for example, by a GPS compass that acquires the orientation of the measurement point 30 from the relative positional relationship between two Global Positioning System (GPS) antennas and acquires the position of the measurement point 30. The position and orientation acquisition device 13 is not limited to a GPS compass as long as it is capable of acquiring the positions and orientations of a plurality of measurement points 30, and may be an electronic compass, a gyro compass, a quantum sensor, or the like.

[0023] The data recording device 14 is a device equipped with storage for recording data of received signals received and processed by the antenna device 10 placed at each measurement point 30, and data on the position and orientation of each measurement point 30 acquired by the position and orientation acquisition device 13.

[0024] The signal processing device 20 is a device that estimates the beam direction and beam width of the beam of the transmission signal transmitted from the base station antenna Tx from the above data recorded in the data recording device 14 (data of the received signal and data of the position and direction of each measurement point 30).

[0025] As shown in FIG. 5, the signal processing device 20 includes a signal synchronization unit 21, a reference signal extraction unit 22, a channel response generation unit 23, an arrival direction estimation unit 24, a base station position estimation unit 25, a received power calculation unit 26, a power distribution calculation unit 27, a beam direction estimation unit 28, and a beam width estimation unit 29.

[0026] The signal synchronization unit 21 uses a synchronization signal included in the received signal received and processed by the antenna device 10 and a corresponding known synchronization signal to perform at least one of time domain synchronization (timing synchronization of symbols, slots, etc.) and frequency domain synchronization (compensation for carrier frequency offset) on the received signal received and processed by the antenna device 10. For example, in the case of the 5G NR (New Radio) standard, at least one of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) included in an SS / PBCH block (Synchronization Signal / Physical Broadcast Channel Block: SSB) is used as a synchronization signal by the signal synchronization unit 21.

[0027] Furthermore, the signal synchronizer 21 acquires an SSB index for identifying the SSB based on the PBCH included in the SSB of the received signal. Since the SSB index has a one-to-one correspondence with the beam radiated from the base station antenna Tx, the signal synchronizer 21 can identify which beam radiated from the base station antenna Tx the received signal corresponds to.

[0028] The reference signal extraction unit 22 is configured to extract a reference signal included in the received signal synchronized by the signal synchronization unit 21. For example, in the case of the 5G NR standard, the reference signal extraction unit 22 extracts reference signals such as a Channel State Information Reference Signal (CSI-RS), a Demodulation Reference Signal (DM-RS), a Tracking Reference Signal (TRS), and a Phase Tracking Reference Signal (PT-RS).

[0029] The channel response generating unit 23 generates a channel response for each beam radiated from the base station antenna Tx for each measurement point 30 from a known reference signal included in the transmission signal transmitted from the base station antenna Tx and a reference signal extracted from the reception signal by the reference signal extracting unit 22. The channel response includes information on the amplitude fluctuation amount and phase fluctuation amount of the reference signal extracted from the reception signal with respect to the known reference signal. For example, in the case of the 5G NR standard, reference signals such as CSI-RS, DM-RS, TRS, and PT-RS extracted from the reception signal by the reference signal extracting unit 22 and the corresponding known reference signals are used to generate a channel response by the channel response generating unit 23.

[0030] The arrival direction estimation unit 24 calculates the arrival direction characteristic of each beam of the transmission signal from the base station antenna Tx for each measurement point 30 based on the channel response of each beam at each measurement point 30 generated by the channel response generation unit 23, and estimates the arrival direction having the highest power level in the calculated arrival direction characteristic of each beam for each measurement point 30. That is, the arrival direction estimation unit 24 estimates the arrival direction of the direct wave of the transmission signal from the base station antenna Tx. For example, the arrival direction estimation unit 24 may be any one that performs arrival direction estimation using an algorithm such as a well-known beamformer, MUSIC (Multiple Signal Classification) method, or FISTA (Fast Iterative Shrinkage-Thresholding Algorithm).

[0031] Specifically, the direction of arrival estimation unit 24 calculates the azimuth angle dependency of the direction of arrival of each beam of the transmission signal from the base station antenna Tx for each measurement point 30 using a set of four antenna elements Rx1 to Rx4 or a set of four antenna elements Rx5 to Rx8, and estimates for each measurement point 30 the azimuth angle showing the highest power level in the calculated azimuth angle dependency.

[0032] Moreover, the arrival direction estimation unit 24 calculates the elevation / depression angle dependency of the arrival direction of each beam of the transmission signal from the base station antenna Tx for each measurement point 30 using a set of four antenna elements Rx1 to Rx4, and estimates the elevation / depression angle showing the highest power level in the calculated elevation / depression angle dependency for each measurement point 30. Similarly, the arrival direction estimation unit 24 calculates the elevation / depression angle dependency of the arrival direction of each beam of the transmission signal from the base station antenna Tx for each measurement point 30 using a set of four antenna elements Rx5 to Rx8, and estimates the elevation / depression angle showing the highest power level in the calculated elevation / depression angle dependency for each measurement point 30.

[0033] The base station position estimation unit 25 estimates the position of the base station antenna Tx by using the direction of arrival at each measurement point 30 for each beam estimated by the direction of arrival estimation unit 24. When estimating the position of the base station antenna Tx, the base station position estimation unit 25 may use the directions of arrival obtained at all measurement points 30, or may use the directions of arrival obtained at some of the measurement points 30.

[0034] FIG. 6 is a diagram for explaining a method for estimating the position of a base station antenna Tx in a horizontal plane (the xy plane on which multiple measurement points 30 are arranged) by the base station position estimation unit 25, and shows a portion of the arrival direction estimated by the arrival direction estimation unit 24 using FISTA, which is one type of compressed sensing.

[0035] As shown in Fig. 6, the base station position estimation unit 25 estimates the position of the intersection of straight lines (arrows in Fig. 6) in the xy plane defined by the azimuth angles φa, φb, and φc of the directions of arrival at, for example, three measurement points 30a, 30b, and 30c, as the position of the base station antenna Tx in the xy plane. If the straight lines of the directions of arrival at each measurement point 30 do not intersect at a single point, the base station position estimation unit 25 estimates the center of gravity of a polygon formed by those intersections as the position of the base station antenna Tx in the xy plane.

[0036] The estimation result of the base station position in the xy plane by the base station position estimation unit 25 is obtained from a set of four antenna elements Rx1 to Rx4 arranged at the same height h1 in the antenna device 10, or a set of four antenna elements Rx5 to Rx8 arranged at the same height h2 in the antenna device 10.

[0037] In addition, when the height direction is the z-axis direction, the base station position estimation unit 25 can also estimate the base station position in a vertical plane (a plane perpendicular to the xy plane) including the measurement point 30, that is, the height of the base station antenna Tx. The result of estimating the height of the base station antenna Tx by the base station position estimation unit 25 is obtained by, for example, determining the position of the intersection point in the same manner as the method of estimating the base station position in the xy plane using the elevation and depression angles of the arrival direction obtained from the set of four antenna elements Rx1 to Rx4 and the elevation and depression angles of the arrival direction obtained from the set of four antenna elements Rx5 to Rx8. In the antenna device 10, if another set of antenna elements is further provided at a height different from the set of four antenna elements Rx1 to Rx4 and the set of four antenna elements Rx5 to Rx8, the base station position estimation unit 25 can obtain the result of estimating the height of the base station antenna Tx by also using the elevation and depression angles obtained from the set of antenna elements to determine the position of the intersection point (or the center of gravity of the polygon).

[0038] The received power calculation unit 26 calculates the maximum received power P r The following calculation is made:

[0039] The power distribution calculation unit 27 calculates the power distribution based on the positions of the measurement points 30 acquired by the position and direction acquisition device 13, the positions of the base station antennas Tx estimated by the base station position estimation unit 25, and the received power P r Based on this, the power distribution P of each beam in the measurement area MA is a The following calculation is made:

[0040] More specifically, the power distribution calculation unit 27 calculates a distance d from the position of the base station antenna Tx estimated by the base station position estimation unit 25 to each measurement point 30, and calculates a free space path loss (FSPL) [dB] according to the following formula (1) using the calculated distance d and the wavelength λ of the beam transmitted from the base station antenna Tx.

[0041]

number

[0042] The received power P at each measurement point 30 r [dBm] is expressed by the following formula (2). Here, G t [dBi] is the antenna gain of the base station antenna Tx, and G r [dBi] is the antenna gain of multiple antenna elements Rx1 to RxN, and P t [dBm] is the transmission power of the base station antenna Tx.

[0043]

number

[0044] Next, the power distribution calculation unit 27 calculates the received power P r From the known antenna gain G of multiple antenna elements Rx1 to RxN r By subtracting and compensating for FSPL, the power distribution P of each beam in the measurement area MA is obtained. a Here, the transmission power P t is assumed to be constant.

[0045]

number

[0046] Next, the power distribution calculation unit 27 calculates the power distribution P of each beam in the measurement area MA by the interpolation method. aFurthermore, the power distribution calculation unit 27 calculates the position of the maximum value of the power distribution P a The position (hereinafter referred to as the "beam boundary") that is -3 dB from the maximum value of is calculated by the interpolation method. FIG. 7(a) shows the power distribution P a The maximum value of is indicated by an asterisk (*), and the position -3 dB from the maximum is indicated by a curve marked -3. Hereinafter, this curve will be referred to as the 3 dB curve.

[0047] The beam direction estimation unit 28 estimates the beam direction of each beam based on the position of the base station antenna Tx estimated by the base station position estimation unit 25 and the maximum value position of each beam calculated by the power distribution calculation unit 27. The beam direction is indicated by the azimuth angle and the elevation / depression angle as seen from the base station antenna Tx.

[0048] As shown in FIG. 7(a), the beam direction estimation unit 28 calculates the power distribution P a In Fig. 7(a), the position of the base station antenna Tx projected on the xy plane and the power distribution P a The x'-axis is taken as the direction connecting the maximum position of the x-axis and the x'-axis. In this case, the angle between the x'-axis and the x-axis is the azimuth angle φ.

[0049] As shown in FIG. 7B, the beam direction estimation unit 28 calculates the elevation / depression angle θ of the beam of the transmission signal based on the position of the base station antenna Tx and the power distribution P a The difference between the horizontal and vertical distances of the maximum values ​​of the

[0050] Here, the difference in vertical distance Δh is expressed as the difference between the height hb of the base station antenna Tx and the height ha of the measurement point 30. Also, the difference in horizontal distance Δl is expressed as the difference between the position of the base station antenna Tx projected on the xy plane and the power distribution P aThat is, the elevation / depression angle θ is calculated by atan(Δh / Δl). Note that the elevation / depression angle θ can be obtained at any height on the xy plane at which the multiple measurement points 30 are arranged, provided that the height provides sufficient received power.

[0051] The beam width estimation unit 29 estimates the beam width of the beam of the transmission signal based on the beam boundary of each beam calculated by the power distribution calculation unit 27. Hereinafter, a method of estimating the beam width by the beam width estimation unit 29 will be described.

[0052] First, the beam width estimation unit 29 estimates the power distribution P a The data of the 3 dB curve is fitted to an ellipse to determine the minor axis radius a and the major axis radius b. The least squares method can be used for this fitting, but other algorithms may also be used.

[0053] FIG. 8 shows an example of fitting by the beam width estimation unit 29. In FIG. 8, the solid line indicates the power distribution P a 8 shows the 3 dB curve of the power distribution P obtained by the power distribution calculation unit 27. a 4 shows the maximum position of

[0054] 9(a) to (c) show examples of calculations of the beam width of a transmission signal beam by the beam width estimation unit 29. As shown in Fig. 9(a), if the apparent angle of the minor axis of the ellipse obtained by the above fitting, as seen from the position where the base station antenna Tx is projected onto the xy plane, is φ0, then φ0 becomes the horizontal beam width.

[0055] In Fig. 9(a), the position of the base station antenna Tx projected on the xy plane and the x1 axis and x2 axis taken in the direction connecting the ends B1 and B2 of the two major axes of the ellipse obtained by the above fitting are also shown. As shown in Fig. 9(b) and (c), if the elevation and depression angles of the base station antenna Tx as seen from the ends B1 and B2 on the x1z plane and the x2z plane are θ1 and θ2, respectively, then θ2-θ1 is the vertical beam width.

[0056] The signal processing device 20 is configured by a control device such as a computer including, for example, a central processing unit (CPU), a graphics processing unit (GPU), a field programmable gate array (FPGA), a read only memory (ROM), a random access memory (RAM), and a hard disk drive (HDD). For example, the signal processing device 20 can configure at least a part of the signal synchronization unit 21, the reference signal extraction unit 22, the channel response generation unit 23, the direction of arrival estimation unit 24, the base station position estimation unit 25, the received power calculation unit 26, the power distribution calculation unit 27, the beam direction estimation unit 28, and the beam width estimation unit 29 in software by execution of a predetermined program by the CPU or the GPU. The above programs are stored in the ROM or the HDD in advance. Alternatively, the above programs may be provided or distributed in a state in which they are recorded in a computer-readable recording medium such as a compact disc or a DVD in an installable or executable format. Alternatively, the above programs may be stored in a computer connected to a network such as the Internet, and provided or distributed by downloading via the network.

[0057] The display device 40 is composed of a display device such as an LCD (Liquid Crystal Display) or a CRT (Cathode Ray Tube), and is adapted to display the estimation results of the azimuth angle, elevation angle, horizontal beam width, and vertical beam width of each beam based on a control signal from the signal processing device 20. Furthermore, the display device 40 is adapted to display operation objects such as buttons, soft keys, pull-down menus, and text boxes for setting various conditions.

[0058] The operation device 41 is for accepting operation input by a user, and is configured, for example, as a touch panel equipped with a touch sensor for detecting a contact position by a touch operation on an input surface corresponding to the display screen of the display device 40. Alternatively, the operation device 41 may be configured to include an input device such as a keyboard or a mouse. For example, a user can input operation input to the operation device 41 to input the wavelength λ of a beam transmitted from the base station antenna Tx, known antenna gains G r etc. can be set.

[0059] The effects of the estimation device 1 according to this embodiment will be confirmed by simulation below.

[0060] First, a beam with desired parameters (azimuth angle, elevation angle, horizontal beam width, vertical beam width) is generated by ray tracing simulation, and the received power P r Here, it is assumed that the base station antenna Tx is installed on the roof of a building with a height of 11 m, and that a plurality of measurement points 30 are arranged in a grid pattern in a measurement area MA, which is assumed to be a communication area, as shown in Fig. 4. It is also assumed that the number of beams from the base station antenna Tx is 12.

[0061] FIG. 10 shows the received power P rUsing the above, the error between the result of estimating the beam parameters using the estimation method by the estimation device 1 of the present invention and the desired parameters of the beam generated by the ray tracing simulation is expressed as the root mean squared error (RMSE) [deg] of 12 beams. In this simulation, the grid spacing of the measurement points 30 is changed in the range of 1 m to 8 m. From the results shown in FIG. 10, it was confirmed that if the grid spacing of the measurement points 30 is about 5 m or less, the beam parameters can be estimated with an RMSE of about 1°.

[0062] An example of the process of an estimation method using the estimation device 1 according to this embodiment will be described below with reference to the flowchart in Fig. 11. In the following process, after data of all beams is acquired at one measurement point 30, similar processes are sequentially performed at other measurement points 30.

[0063] First, the antenna device 10 and the position and orientation acquisition device 13 mounted on a drone or the like are placed at any one of a plurality of measurement points 30 within a measurement area MA (step S1).

[0064] Next, the antenna device 10 receives the beam of the transmission signal transmitted from the base station antenna Tx as a reception signal by the multiple antenna elements Rx1 to RxN, and performs reception processing such as amplification, frequency conversion, and analog-to-digital conversion on the reception signal (step S2).

[0065] Next, the signal synchronization unit 21 performs at least one of time domain synchronization and frequency domain synchronization on the received signal using a synchronization signal contained in the received signal that has been received and processed by the antenna device 10 and a corresponding known synchronization signal (signal synchronization step S3).

[0066] Next, the signal synchronizer 21 acquires an SSB index for identifying the SSB based on the PBCH included in the SSB of the received signal, and identifies the beam transmitted from the base station antenna Tx (step S4).

[0067] Next, the reference signal extractor 22 extracts a reference signal contained in the received signal synchronized by the signal synchronizer 21 (reference signal extracting step S5).

[0068] Next, the channel response generation unit 23 generates a channel response of the beam identified in step S4 from a known reference signal contained in the transmission signal transmitted from the base station antenna Tx and a reference signal extracted from the received signal by reference signal extraction step S5 (channel response generation step S6).

[0069] Next, the signal processing device 20 judges whether or not the channel responses of all beams that can be transmitted from the base station antenna Tx have been generated in the channel response generating step S6. If the channel responses of all beams have been generated in the channel response generating step S6 (step S7: YES), the signal processing device 20 executes the processes in and after step S8. If the channel responses of all beams have not been generated in the channel response generating step S6 (step S7: NO), the signal processing device 20 executes the processes in and after step S2 again for beams for which the channel responses have not yet been obtained.

[0070] Next, the signal processing device 20 judges whether the antenna device 10 and the position and orientation acquisition device 13 are placed at all the measurement points 30 in the measurement area MA. If the antenna device 10 and the position and orientation acquisition device 13 are placed at all the measurement points 30 in the measurement area MA (step S8: YES), the signal processing device 20 executes the processes of step S9 and onward. If the antenna device 10 and the position and orientation acquisition device 13 are not placed at all the measurement points 30 in the measurement area MA (step S8: NO), the signal processing device 20 executes the processes of step S1 and onward again to place the antenna device 10 and the position and orientation acquisition device 13 at the measurement points 30 where the antenna device 10 and the position and orientation acquisition device 13 are not yet placed.

[0071] Next, the arrival direction estimation unit 24 calculates the arrival direction characteristics of each beam of the transmission signal from the base station antenna Tx for each measurement point 30 based on the channel response of each beam at each measurement point 30 generated in the channel response generation step S6, and estimates the arrival direction with the highest power level for each measurement point 30 in the calculated arrival direction characteristics of each beam (arrival direction estimation step S9).

[0072] The base station position estimation unit 25 estimates the position of the base station antenna Tx by using the direction of arrival at each measurement point 30 for each beam estimated in the direction of arrival estimation step S9 (base station position estimation step S10).

[0073] The received power calculation unit 26 calculates the maximum received power P r (received power calculation step S11).

[0074] The power distribution calculation unit 27 uses the positions of the measurement points 30 acquired by the position and direction acquisition device 13, the positions of the base station antennas Tx estimated in the base station position estimation step S10, and the received power P r Based on this, the power distribution P of each beam in the measurement area MA is a The maximum value position, which is the position of the maximum value of the power distribution, and the beam boundary, which is the position 3 dB lower than the maximum value, are calculated (power distribution calculation step S12).

[0075] The beam direction estimation unit 28 estimates the beam direction of each beam, i.e., the azimuth angle and elevation / depression angle of the maximum value position of each beam as seen from the base station antenna Tx, based on the position of the base station antenna Tx estimated in the base station position estimation step S10 and the maximum value position of each beam calculated in the power distribution calculation step S12 (beam direction estimation step S13).

[0076] The beam width estimation unit 29 estimates the beam width of the beam of the transmission signal, i.e., the horizontal beam width and vertical beam width in the xy plane on which the measurement point 30 exists, based on the beam boundaries of each beam calculated in the power distribution calculation step S12 (beam width estimation step S14).

[0077] Next, the display device 40 displays the estimated azimuth angle, elevation angle, horizontal beam width, and vertical beam width of each beam (step S15).

[0078] As described above, the estimation device 1 according to this embodiment is configured to estimate the arrival direction of multiple beams of a transmission signal transmitted from the base station antenna Tx for each measurement point 30, and estimate the position of the base station antenna Tx using the estimated arrival directions of the multiple beams. Here, the estimation device 1 according to this embodiment is configured to estimate the arrival direction of each beam with the highest power level for each measurement point 30. Furthermore, the estimation device 1 according to this embodiment is configured to estimate the beam direction and beam width of each beam based on the position of the base station antenna Tx and the power distribution of each beam.

[0079] As a result, the estimation device 1 of this embodiment can estimate the direction of arrival of the direct wave of the transmission signal from the base station antenna Tx, and can estimate the beam direction and beam width of the beam transmitted from the base station antenna Tx without performing pre-calculation using a map. [Explanation of symbols]

[0080] 1 Estimation device 10 Antenna device 11 Receiver 11-1~11-N Receiver 13 Position / azimuth acquisition device 14 Data recording device 20 Signal Processing Device 21 Signal Synchronization Section 22 Reference signal extraction section 23 Channel response generator 24 Direction of Arrival Estimator 25 Base station position estimation section 26 Received power calculation unit 27 Power distribution calculation section 28 Beam direction estimation unit 29 Beam width estimation unit 30,30a,30b,30c measurement points 100 base stations Tx base station antenna Rx1~RxN antenna elements MA Measurement Area

Claims

1. an antenna device (10) having a plurality of antenna elements (Rx1 to RxN) and receiving a plurality of beams of a transmission signal transmitted from a base station antenna (Tx) as a reception signal by the plurality of antenna elements at a plurality of measurement points (30) within a measurement area (MA); A position and orientation acquisition device (13) that acquires the position and orientation of each of the measurement points where the antenna devices are arranged; a data recording device (14) for recording data of the received signals received by the antenna devices arranged at each of the measurement points and data of the positions and directions of each of the measurement points acquired by the position and direction acquisition device; a signal processing device (20) that estimates a beam direction and a beam width of each of the beams from the data of the received signal recorded in the data recording device and the data of the position and direction of each of the measurement points; The signal processing device includes: A reference signal extraction unit (22) that extracts a reference signal included in the received signal; a channel response generating unit (23) that generates a channel response of each of the beams from a known reference signal included in the transmission signal and the reference signal extracted from the reception signal by the reference signal extracting unit; an arrival direction estimation unit (24) that estimates an arrival direction in which each of the beams has the highest power level for each of the measurement points based on the channel response of each of the beams generated by the channel response generation unit; a base station position estimation unit (25) that estimates a position of the base station antenna using the arrival direction estimated by the arrival direction estimation unit; a reception power calculation unit (26) for calculating reception power of the plurality of antenna elements at each of the measurement points; a power distribution calculation unit (27) that calculates a maximum position, which is a position of a maximum value of the power distribution of each of the beams in the measurement area, and a beam boundary, which is a position 3 dB lower than the maximum value, based on the positions of each of the measurement points, the position of the base station antenna estimated by the base station position estimation unit, and the received power calculated by the received power calculation unit; a beam direction estimation unit (28) that estimates a beam direction of each of the beams based on the position of the base station antenna estimated by the base station position estimation unit and the maximum value position of each of the beams calculated by the power distribution calculation unit; a beam width estimation unit (29) that estimates a beam width of the beam based on the beam boundary of each of the beams calculated by the power distribution calculation unit.

2. an antenna device (10) having a plurality of antenna elements (Rx1 to RxN) and receiving a plurality of beams of a transmission signal transmitted from a base station antenna (Tx) as a reception signal by the plurality of antenna elements at a plurality of measurement points (30) within a measurement area (MA); A position and orientation acquisition device (13) that acquires the position and orientation of each of the measurement points where the antenna devices are arranged; a data recording device (14) for recording data of the received signals received by the antenna devices arranged at each of the measurement points and data of the positions and directions of each of the measurement points acquired by the position and direction acquisition device; and a signal processing device (20) that estimates a beam direction and a beam width of each of the beams from the data of the received signal recorded in the data recording device and the data of the positions and directions of each of the measurement points, the estimation method using the estimation device (1), comprising: A reference signal extraction step (S5) of extracting a reference signal included in the received signal; A channel response generating step (S6) of generating a channel response of each of the beams from a known reference signal included in the transmission signal and the reference signal extracted from the reception signal by the reference signal extracting step; an arrival direction estimating step (S9) of estimating an arrival direction having the highest power level of each of the beams for each of the measurement points based on the channel response of each of the beams generated by the channel response generating step; a base station position estimating step (S10) of estimating a position of the base station antenna using the arrival direction estimated by the arrival direction estimating step; A reception power calculation step (S11) of calculating reception power of the plurality of antenna elements at each of the measurement points; a power distribution calculation step (S12) of calculating a maximum position, which is a position of a maximum value of the power distribution of each of the beams in the measurement area, and a beam boundary, which is a position 3 dB lower than the maximum value, based on the positions of each of the measurement points, the positions of the base station antennas estimated by the base station position estimation step, and the received power calculated by the received power calculation step; a beam direction estimation step (S13) of estimating a beam direction of each of the beams based on the position of the base station antenna estimated by the base station position estimation step and the maximum value position of each of the beams calculated by the power distribution calculation step; A beam width estimation step (S14) of estimating a beam width of the beam based on the beam boundary of each of the beams calculated by the power distribution calculation step.

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