JP2022094197A - Position estimation device, position estimation method, and program - Google Patents

Abstract

To provide a position estimation device for estimating an installation position of a base station, a transmission power and a radio wave transmission direction in a spectrum sharing system.SOLUTION: A position estimation device includes a detection unit 20 for detecting a communication signal, and an arithmetic unit 12 for estimating an installation position, a transmission direction, and a transmission power of the communication signal based on detection values of a reception power and an arrival direction of the communication signal and a position of the detection unit which are detected by the detection unit at least at two locations. The arithmetic unit sets parameters including the installation position, the transmission direction, and the transmission power based on the detected values. The arithmetic unit calculates a direction error between the arrival direction and an estimated transmission direction calculated including the parameters. The arithmetic unit calculates a power error between the reception power and an estimated reception power calculated including the parameters. The arithmetic unit changes the parameters in the retrieval region where ranges of the parameters are set. The arithmetic unit calculates the parameters for minimizing the sum of errors of the direction error and the power error. The calculation unit estimates the installation position, the transmission power, and the transmission direction of a base station based on the calculated parameters.SELECTED DRAWING: Figure 1

Description

The present invention relates to a position estimation device, a position estimation method, and a program for improving the utilization efficiency of radio waves.

In recent years, the communication speed in wireless communication has increased, and the communication capacity has also increased. In wireless communication, in order to improve the efficiency of radio wave utilization, a frequency sharing system is operated in which communication systems of different operators use radio waves of the same frequency in a predetermined frequency band. In a frequency sharing system, frequency bands that are free for each time or region are assigned to different communication systems while suppressing radio wave interference.

In the frequency sharing system, there are a Primary User (PU, primary user) who uses the first communication system and a Secondary User (SU, secondary user) who uses a second communication system different from the first communication system. The PU has a high communication right, and the SU has a lower priority than the PU. In the frequency sharing system, when the PU is communicating in a predetermined frequency band, SU communication may be allocated to an empty area other than the area in which the PU is communicating.

In order to prevent interference between the first communication of the first communication system used by the PU and the second communication of the second communication system used by the SU, in the communication environment of the frequency sharing system, a free area in the first communication is previously reserved. Need to be detected.

S. Nardone, A. Lindgren, and Kai Gong, “Fundamental properties and performance of conventional bearings-only target motion analysis,” IEEE Transactions on Automatic Control, vol. 29, no. 9, pp. 775-787, 1984. A. Molisch, “Wireless Communications”, John Wiley & Sons Ltd., 2011 ISBN: 978-0-470-74187-0

Of the wireless base stations, temporary wireless base stations and some wireless base stations that do not require a license are not registered in the wireless license database, and the installation location may be unknown. Further, when the base station transmits and receives by an antenna having directivity, it is necessary to accurately estimate the radio wave transmission angle of the base station in order to detect the free area of the frequency.

The present invention provides a position estimation device, a position estimation method, and a program capable of estimating the installation position, transmission power, and radio wave transmission direction of a base station in a frequency sharing system and extracting an empty area in a predetermined frequency band. The purpose.

One aspect of the present invention is a position estimation device that estimates the installation position, transmission power, and transmission direction of a base station that transmits a directional communication signal, the detection unit that detects the communication signal, and the detection. Calculation to estimate the installation position, the transmission direction, and the transmission power of the communication signal based on the detected values of the reception power, the arrival direction, and the position of the detection unit of the communication signal detected at at least two places by the unit. The calculation unit includes the unit, and the calculation unit sets parameters including the installation position, the transmission direction, and the transmission power based on the detection value, and calculates the arrival direction and the estimation including the parameters. The direction error with the transmission direction is calculated, the power error between the received power and the estimated received power calculated including the parameter is calculated, and the parameter is changed in the search area in which the range of the parameter is set. It is a position estimation device that calculates the parameter that minimizes the sum of the errors of the direction error and the power error, and estimates the installation position, the transmission power, and the transmission direction based on the calculated parameters.

One aspect of the present invention is a position estimation method for estimating the installation position, transmission power, and transmission direction of a base station that transmits a directional communication signal, and the communication signal is detected by a detection unit at at least two locations. Then, based on the detected values of the received power, the arrival direction, and the position of the detection unit of the detected communication signal, the parameters including the installation position, the transmission direction, and the transmission power are set, and the arrival direction is set. And, the direction error with the estimated transmission direction calculated including the parameter is calculated, the power error between the received power and the estimated received power calculated including the parameter is calculated, and the range of the parameter is set. The parameter is changed in the searched search area, the parameter that minimizes the sum of the errors of the direction error and the power error is calculated, and the installation position, the transmission power, and the transmission power are calculated based on the calculated parameters. This is a position estimation method that calculates an estimated value in the transmission direction.

One aspect of the present invention is a program executed in a position estimation device that estimates the installation position, transmission power, and transmission direction of a base station that transmits a directional communication signal, and is executed by a detection unit at at least two locations. The communication signal is detected, and parameters including the installation position, the transmission direction, and the transmission power are set based on the detected values of the received power, the arrival direction, and the position of the detection unit of the detected communication signal. The direction error between the arrival direction and the estimated transmission direction calculated including the parameter is calculated, and the power error between the received power and the estimated received power calculated including the parameter is calculated. The parameter is changed in the search area in which the parameter range is set, the parameter that minimizes the sum of the errors of the direction error and the power error is calculated, and the installation position and the said are based on the calculated parameter. It is a program to calculate the transmission power and the estimated value of the transmission direction.

In the frequency sharing system, the installation position of the base station, the radio wave strength, and the radio wave transmission direction can be estimated, and an empty area in a predetermined frequency band can be extracted.

It is a block diagram which shows the structure of the position estimation apparatus which concerns on embodiment. It is a figure which conceptually shows the radio wave available area estimated by a position estimation device. It is a figure which conceptually shows the existing estimation method of the installation position of a base station. It is a figure which conceptually shows the detection method in a detection part. It is a figure which conceptually shows the calculation method of the estimated value of an installation position. It is a figure which conceptually shows the error of the estimated value of the installation position when the transmission radio wave of a base station is transmitted in a wide angle. It is a figure which conceptually shows the error of the estimated value of the installation position when the transmission radio wave of a base station is transmitted in a narrow angle. It is a figure which conceptually shows the state which a base station communicates with a directional antenna. It is a figure which conceptually shows the state which a base station communicates with a directional antenna. It is a figure which conceptually shows the installation position of the base station which concerns on embodiment, and the method of estimating the transmission angle. It is a figure which conceptually shows the estimation method of the received power of the base station which concerns on embodiment. It is a figure which conceptually shows the search grid used for estimating the installation position of a base station. It is a figure which conceptually shows the search grid used for estimating the transmission angle and transmission power of a base station. It is a figure which conceptually shows the calculation method of a base station installation position, transmission power, and transmission direction. It is a flow chart showing the processing of the position estimation method. It is a figure which compares the accuracy of a position estimator and an existing method.

Hereinafter, the position estimation device, the position estimation method, and the embodiment of the program according to the present invention will be described. The position estimation device estimates, for example, the installation position and transmission direction of a base station that transmits a communication signal having directivity based on a received signal acquired from a detection unit.

As shown in FIG. 1, the position estimation device 10 has, for example, a calculation unit 12 that performs calculation processing, a storage unit 14 that stores various data required for calculation, and a display that displays a predetermined image based on the calculation result. A unit 16 is provided.

The arithmetic unit 12 is realized by, for example, a hardware processor such as a CPU (Central Processing Unit) executing a program (software). Some or all of these components are hardware (circuit parts) such as LSI (Large Scale Integration), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array), GPU (Graphics Processing Unit). It may be realized by (including circuits), or it may be realized by the cooperation of software and hardware. The program may be stored in advance in a storage device such as an HDD (Hard Disk Drive) or a flash memory, or may be stored in a removable storage medium such as a DVD or a CD-ROM, and the storage medium is stored in the drive device. It may be installed by being attached.

The storage unit 14 is a storage device such as an HDD (Hard Disk Drive) or a flash memory. In addition to the data such as the threshold value described later, a program for executing the processing of the calculation unit 12 is stored. Data and programs may be stored in an external server connected to the network.

As the display unit 16, for example, a display device such as a liquid crystal display, an LED (Light Emitting Diode) display, an organic EL (Organic Electro-Luminescence) display, a digital mirror device, or a plasma display is used.

The detection unit 20 intercepts the communication signal and detects the received signal in the communication environment in which the communication signal is transmitted from the base station. The detection unit 20 includes, for example, an antenna having directivity. For example, the detection unit 20 rotates the antenna, fixes the antenna in the direction in which the reception intensity of the received signal is highest, measures the received signal, and acquires the measured values of the radio wave strength and the antenna angle (arrival direction of the radio wave). .. One or more detection units 20 may be provided. One or more of the plurality of detection units 20 may output the detection value to the calculation unit 12. The detection unit 20 may output the detection value to the calculation unit 12 through the network. Further, the detection unit 20 also detects its own position data based on the GPS coordinate data. The detection unit 20 measures the antenna angle with, for example, a magnetic compass.

Next, the measurement method of the position estimation device 10 will be described.

As shown in FIG. 2, the position estimation device 10 estimates the first communication area R1 of the first communication system (primary user) in which the base station 30 communicates with another base station 40. The base stations 30 and 40 communicate using, for example, an antenna having directivity. By estimating the first communication area R1 with which the base stations 30 and 40 are communicating, it is possible to estimate the second communication area R2 to which the communication radio waves of the base stations 30 and 40 do not reach. In the frequency sharing technique in which different wireless communication systems use the same frequency band, the communication of the second communication system (secondary user) can be assigned to the second communication area R2.

As shown in FIGS. 3 to 5, for example, a method of measuring the transmitted radio wave from the base station 30 to estimate the position of the base station 30 has been proposed (see, for example, Non-Patent Document 1). The estimated position p of the base station 30 is estimated based on the detection result of the detection unit 20 including the antenna having directivity. For example, in the first communication area R1 of the base station 30, measured values are acquired at a plurality of measurement points.

The detection unit 20 includes, for example, an antenna having directivity. In the measurement, the antenna of the detection unit 20 is rotated to measure the angle in the direction in which the intensity of the received radio wave is the highest. The measured angle is estimated to be the arrival angle of the transmitted radio wave φ ~ _{R, 1} , φ ~ _{R, 2} , ... φ ~ _{R, N} (N: number of measurement points). The i-th measured arrival angle φ ~ _{R, i} includes the direction error ε _{φ, i} .

方向誤差は、到来方向の測定値φ~_Ｒ,iと、パラメータを含んで算出される推定送信方向φ_Ｒ,i（ｐ）との差分により算出される。 The direction error is calculated using the following equation (1), where the i-th estimated angle φ _{R, i} (p) of the estimated position p with p as a parameter and the measured values φ to _{R, i} .

The direction error is calculated by the difference between the measured values φ to _{R, i} in the arrival direction and the estimated transmission direction φ _{R, i} (p) calculated including the parameters.

図５に示されるように、基地局３０の推定位置ｐ＾は、誤差の総和e(p)が最小となる位置である。推定位置ｐ＾は、ｐをパラメータとして変化させ、誤差の総和e(p)を最小化して算出される。 The total error e (p) of the measured values φ to _{R, i} at a plurality of measurement points is calculated using the following equation (2).

As shown in FIG. 5, the estimated position p ^ of the base station 30 is a position where the total error e (p) is minimized. The estimated position p ^ is calculated by changing p as a parameter and minimizing the total error e (p).

As shown in FIG. 6, when the transmission radio wave of the base station 30 is transmitted at a wide angle, and when the arrival angle measured by the detection unit 20 contains a small angle error, it is included in the calculation result of the estimated position. The effect on the error is small.

As shown in FIG. 7, when the transmitted radio wave of the base station 30 has directivity and is transmitted at a narrow angle, and when the arrival angle measured by the detection unit 20 includes a small angle error. The influence on the error included in the calculation result of the estimated position may be large.

As shown in FIGS. 8 and 9, when the transmission radio waves of the base stations 30 and 40 have directivity and the communication radio waves are transmitted and received in the narrow angle first communication region R1, they can be shared in the frequency sharing system. In order to detect an empty area (second communication area R2) having a high frequency, it is necessary to estimate the transmission direction of the transmitted radio wave in addition to the installation position of the base station 30.

Hereinafter, a method of estimating the installation position of the base station 30 and the transmission direction of the transmitted radio wave in the position estimation device 10 will be described. For example, the position estimation device 10 estimates the installation position and the transmission direction of the base station 30 based on the detection values of the plurality of arrival directions and the received powers detected by the detection unit 20 in addition to the method described in Patent Document 1. do.

As shown in FIG. 10, the detection unit 20 is used to determine the arrival directions φ to _{R, i} and the received powers P to _{R, i} of the transmission signal transmitted from the base station 30 that transmits the communication signal having directivity. To detect. The detection unit 20 rotates the antenna (see FIG. 4) to detect the communication signal of the base station 30. In the detection unit 20, the antenna is fixed at the angle of the antenna at which the communication signal is detected to be the highest, and the arrival direction φ ~ _{R, i} (angle data), the received power P ~ _{R, i} , and the position of the detection unit 20 at that time. Store the detected value. The detection unit 20 detects the received powers P to _{R, i} of the communication signal, the arrival directions φ to _{R, i} , and the detection values of the positions of the detection unit 20 at at least two places. The installation position p of the base station 30 is set as a parameter. Further, q = [ _PT φ _T ] including the transmission direction φ _T and the transmission power _PT is set as parameters.

式（３）に示されるように、電力誤差は、受信電力P~_R,iとパラメータを含んで算出される推定受信電力P_R,i(p,q)との差分である。 The direction error included in the arrival angles φ to _{R, i} detected by the detection unit 20 is calculated by the above equation (1) with p as a parameter. The power error included in the received powers P to _{R, i} detected by the detection unit 20 is calculated by the following equation (3) with p and q as parameters.

As shown in the equation (3), the power error is the difference between the received powers P to _{R, i} and the estimated received powers P _{R, i} (p, q) calculated including the parameters.

但し、λ：波長、Ｇ_Ｒ：検出部２０の受信アンテナの利得、Ｇ_Ｔ，φ：送信方向の角度の利得パターン、d_i：ｐに基づいて算出された基地局３０と検出部２０との間の距離である。 As shown in FIG. 11, the estimated received power PR _{, i} (p, q) is calculated by, for example, the following equation (4) using the method described in Patent Document 2.

However, λ: wavelength, _GR : gain of the receiving antenna of the detection unit 20 _{, GT, φ} : gain pattern of the angle in the transmission direction, _di : p, and the base station 30 and the detection unit 20 calculated based on p. The distance between.

但し、Ｎ：検出部２０の検出位置の数、σ^２ _φ：送信方向のエラー分散、σ^２ _Ｐ：受信電力のエラー分散である。式（５）において、符号が正となるように、正規化された方向誤差の二乗和と、正規化された電力誤差の二乗和との和に基づいて、誤差の総和であるエラーe(p,q)が算出される。演算部１２は、式（５）を用いてパラメータｐ，ｑを変化させた数値計算を行う。 The estimated value of the installation position of the base station 30, the transmission direction, and the estimated value of the transmission power (estimated transmission power) are the direction error calculated based on the equation (1) and the equation (3) with p and q as parameters. It is determined by calculating the parameter that minimizes the total error (error e (p, q)) with the power error calculated based on. The error e (p, q) is calculated using, for example, the following equation (5).

However, N: the number of detection positions of the detection unit 20, σ ² _φ : error dispersion in the transmission direction, and σ ² _P : error dispersion of received power. In equation (5), the error e (p) is the sum of the errors based on the sum of the squared sum of the normalized directional errors and the squared sum of the normalized power errors so that the sign is positive. , Q) is calculated. The calculation unit 12 performs numerical calculation by changing the parameters p and q using the equation (5).

As shown in FIG. 12, in the estimation of the installation position of the base station 30 using the equation (5), the search grid G1 (search area) for the installation position including the position of the base station 30 is set. The search grid G1 has M (M: natural numbers) on the coordinates set by the predetermined gain within the region of the predetermined range p (x _min -x _max , y _min -y _max ) set on the coordinates. Has a grid. The gains of the plurality of grids are set with the desired accuracy and the processing power of the computer. The estimated value of the installation position of the base station 30 is calculated by applying the coordinates of each grid to the equation (5).

As shown in FIG. 13, in the estimation of the transmission power of the base station 30 using the equation (5), the search grid G2 for the transmission power showing the relationship between the transmission direction φ _T of the base station 30 and the transmission power _PT . (Search area) is set. The search grid G2 is on the coordinates set by the predetermined gain within the region of the predetermined range q (φ _{T, min} −φ _{T, max} , P _{T, min} −P _{T, max} ) set on the coordinates. It has k (k: natural numbers) grids. The gains of the plurality of grids are set with the desired accuracy. The estimated value of the transmission power of the base station 30 is calculated by applying the coordinates of each grid to the equation (5). The calculation unit 12 changes the parameters p and q corresponding to the plurality of grids, and calculates the estimated values of the installation position p of the base station 30, the transmission direction φ _T , and the transmission power _PT of the communication signal.

As shown in FIG. 14, each coordinate in each grid in the search grids G1 and G2 is applied to the equation (5), and the minimum value of the error e (p, q) is searched. The parameters p and q that minimize the error e (p, q) are calculated by the search. Based on the calculated parameters p and q, the estimated values of the installation position p of the base station 30, the transmission direction φ _T , and the transmission power _PT of the communication signal are calculated.

The display unit 16 displays a display image based on the calculation result of the calculation unit 12. For example, the calculation unit 12 may generate an image showing the position, transmission direction, and transmission power of the base station 30 on the map data and display it on the display unit 16.

Next, the flow of processing of the position estimation method using the position estimation device 10 will be described.

As shown in FIG. 15, the arithmetic unit 12 causes the detection unit 20 to detect the communication signal of the base station 30 at at least two places (step S100). The calculation unit 12 sets parameters including the installation position, the transmission direction, and the transmission power based on the detected values of the received power, the arrival direction, and the position of the detection unit of the communication signal detected by the detection unit 20 (step). S102). The calculation unit 12 calculates a direction error between the arrival direction and the estimated transmission direction calculated including the parameter (step S104).

The calculation unit 12 calculates a power error between the received power and the estimated received power calculated including the parameter (step S106). The calculation unit 12 calculates the total error based on the sum of the squared sum of the normalized direction errors and the squared sum of the normalized power errors. The calculation unit 12 changes the parameter in the search area in which the parameter range is set, and calculates the parameter that minimizes the sum of the direction error and the power error (step S108). The calculation unit 12 calculates an estimated value of the installation position and the transmission direction based on the calculated parameter (step S110).

FIG. 16 shows a CDF (cumulative distribution function) of the position error between the estimated value of the installation position of the base station 30 by the position estimation device 10 and the estimated value by the existing method described in Non-Patent Document 1. Has been done. The position error _ed of the installation position is calculated by the equation (6) assuming that the estimated value of the installation position of the base station 30 is p ^ and the actual position of the base station 30 is p _true .

The central distance error of the estimated value of the installation position calculated by the position estimation device 10 is 164.0 m, whereas the estimated value of the installation position by the conventional method is 326.9 m. According to the position estimation device 10, the accuracy is improved by about 160 m as compared with the conventional method. According to the position estimation device 10, it is possible to significantly reduce the error of the estimated value of the installation position of the base station 30 as compared with the existing method. According to the position estimation device 10, for example, in an outdoor communication environment, it is possible to estimate the installation position of the base station, the transmission power, and the radio wave transmission direction, and perform ray tracing to track the communication radio wave.

According to the position estimation device 10, ray tracing that tracks the communication radio wave can simulate the first communication area R1 and the other second communication area R2 of the transmission radio wave transmitted from the base station 30.

As described above, according to the position estimation device 10, it is possible to calculate the estimated value of the installation position of the base station, the transmission power, and the radio wave transmission direction in the frequency sharing system. According to the position estimation device 10, the first communication area R1 of the base station 30 can be estimated based on the calculated estimated value, and the second communication area R2 which is a free area in a predetermined frequency band can be extracted. According to the position estimation device 10, it is possible to improve the utilization efficiency of radio waves in the frequency sharing system.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and variations thereof are included in the scope of the invention described in the claims and the equivalent scope thereof, as are included in the scope and gist of the invention.

10 Position estimation device 12 Calculation unit 14 Storage unit 16 Display unit 20 Detection unit 30 Base station 40 Base station G1 Search grid G2 Search grid R1 First communication area R2 Second communication area

Claims (6)

A position estimation device that estimates the installation position, transmission power, and transmission direction of a base station that transmits a communication signal with directivity.
A detector that detects the communication signal and
The installation position, the transmission direction, and the transmission power of the communication signal are estimated based on the detection values of the reception power, the arrival direction, and the position of the detection unit of the communication signal detected at at least two places by the detection unit. With a calculation unit
The calculation unit sets parameters including the installation position, the transmission direction, and the transmission power based on the detected value.
Calculate the direction error between the arrival direction and the estimated transmission direction calculated including the parameters.
Calculate the power error between the received power and the estimated received power calculated including the parameters.
The parameter is changed in the search area in which the range of the parameter is set, the parameter that minimizes the sum of the errors of the direction error and the power error is calculated, and the installation position is based on the calculated parameter. A position estimation device that estimates the transmission power and the transmission direction. The search area is set by a plurality of grids set by a predetermined gain.
The position estimation device according to claim 1. The arithmetic unit changes the parameter corresponding to the plurality of grids.
The position estimation device according to claim 2. The arithmetic unit calculates the sum based on the sum of the normalized sum of squares of the direction errors and the sum of the normalized sums of squares of the power errors.
The position estimation device according to any one of claims 1 to 3. It is a position estimation method that estimates the installation position, transmission power, and transmission direction of a base station that transmits a communication signal with directivity.
The communication signal is detected by the detection unit at at least two places, and the communication signal is detected.
Based on the detected values of the received power, the arrival direction, and the position of the detection unit of the detected communication signal, parameters including the installation position, the transmission direction, and the transmission power are set.
Calculate the direction error between the arrival direction and the estimated transmission direction calculated including the parameters.
Calculate the power error between the received power and the estimated received power calculated including the parameters.
The parameter is changed in the search area in which the range of the parameter is set, and the parameter that minimizes the sum of the errors between the direction error and the power error is calculated.
Based on the calculated parameters, the estimated values of the installation position, the transmission power, and the transmission direction are calculated.
Position estimation method. A program executed by a position estimation device that estimates the installation position, transmission power, and transmission direction of a base station that transmits a directional communication signal.
The communication signal is detected by the detection unit at at least two places, and the communication signal is detected.
Based on the detected values of the received power, the arrival direction, and the position of the detection unit of the detected communication signal, the parameters including the installation position, the transmission direction, and the transmission power are set.
The direction error between the arrival direction and the estimated transmission direction calculated including the parameter is calculated.
The power error between the received power and the estimated received power calculated including the parameters is calculated.
The parameter is changed in the search area in which the range of the parameter is set, and the parameter that minimizes the sum of the errors between the direction error and the power error is calculated.
Based on the calculated parameters, the estimated values of the installation position, the transmission power, and the transmission direction are calculated.
program.

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