JP2016100667A - Calculation device, calculation method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a calculation device for calculating reception signal strength of a radio wave in a building.SOLUTION: A calculation device 1 comprises: a radio wave information storage unit 12 in which radio wave information including a frequency of a radio wave transmitted from a wave source and information on strength of the radio wave is stored; a building information storage unit 13 in which building information including building position information showing a position of a building and a frequency characteristic of a radio wave screened out by a partition body of the building is stored; and a calculation unit 14 for calculating, by using the radio wave information and the building information, reception signal strength of the radio wave transmitted from the wave source, in the building.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a calculation device or the like that calculates signal intensity of a radio wave transmitted from a wave source in a building.

  In recent years, effective use of frequency bands (white space) that are not used spatially and temporally as one of the means to improve frequency utilization efficiency to cope with the tightness of frequency resources and the explosive increase in mobile traffic. Is mentioned. As described above, in order to efficiently use the vacant frequency band, it is necessary to appropriately grasp the spatial and temporal vacancy conditions for each frequency.

As such a white space detection method, for example, there is a method using a spectrum sensing technique. In this method, the white space region can be detected by determining the presence or absence of a spectrum at the position where the sensor (receiving device) is arranged.
For example, a device described in Patent Document 1 is known as a device for detecting an unused frequency spectrum.

Special table 2012-529196 gazette

Conventionally, a white space is defined without distinguishing between the inside and the outside of a building on the assumption that the building transmits radio waves. However, in reality, radio waves may be attenuated on the outer walls of buildings, walls of rooms, windows, etc. In such cases, for example, outside the building is not white space, but inside the building It can be a white space.
Generally speaking, there has been a demand for knowing the signal strength of radio waves in a building in consideration of the attenuation of radio waves in a building partition.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a calculation device or the like that can calculate the signal strength of radio waves in a building.

In order to achieve the above object, a calculation apparatus according to the present invention includes a radio wave information storage unit that stores radio wave information having a frequency of a radio wave transmitted from a wave source and information on the strength of the radio wave, and a building that indicates a position of the building. The building information storage unit that stores the building information including the position information and the frequency characteristics of the radio wave shielded by the building partition, and the radio wave transmitted from the wave source using the radio wave information and the building information. And a calculation unit for calculating the received signal strength at.
With such a configuration, it is possible to know the received signal strength of radio waves in a building using building information including frequency characteristics of radio waves shielded by the building partition. As a result, for example, it is possible to determine whether or not communication using radio waves having the same frequency as radio waves from a wave source can be performed in a building.

In the calculation device according to the present invention, the radio wave information includes the transmission power of the radio wave transmitted from the wave source and the position of the wave source, and the calculation unit includes the radio wave information and the building position information, and a predetermined radio wave. The received signal strength of the radio wave at the position of the building may be calculated using the attenuation characteristics of the building, and the received signal strength in the building may be calculated using the received signal strength, the frequency characteristics, and the frequency of the radio wave.
With such a configuration, even if the attenuation characteristic of the radio wave from the wave source is not known, the received signal strength of the radio wave in the building can be calculated.

In the calculation device according to the present invention, the radio wave information includes the reception position of the radio wave transmitted from the wave source, the received signal strength of the radio wave received at the reception position, the transmission power of the radio wave transmitted from the wave source, and the wave source The calculation unit calculates the received signal strength at the position of the building by calculating the attenuation characteristics of the radio wave transmitted from the wave source using the radio wave information and the building position information, and the received signal strength and frequency characteristics. The received signal strength in the building may be calculated using the frequency of the radio wave.
With such a configuration, the attenuation characteristic of the radio wave from the wave source is calculated, and the received signal intensity of the radio wave in the building is calculated using the attenuation characteristic. Therefore, more accurate calculation of the received signal intensity can be realized.

In the calculation device according to the present invention, the radio wave information includes a plurality of sets of reception positions of radio waves transmitted from the wave source and received signal strengths of radio waves received at the reception positions. The received signal strength at the position of the building may be specified using the position information, and the received signal strength in the building may be calculated using the received signal strength, frequency characteristics, and radio wave frequency.
With such a configuration, since the received signal strength of the radio wave in the building is calculated using the received signal strength itself included in the radio wave information, there is an advantage that the received signal strength in the building can be calculated more easily.

In the calculation device according to the present invention, the radio wave information includes a plurality of sets of reception positions of radio waves transmitted from the wave source and received signal strengths of radio waves received at the reception positions. The received signal strength at the position of the building may be estimated using the position information, and the received signal strength within the building may be calculated using the received signal strength, frequency characteristics, and radio wave frequency.
With such a configuration, for example, even if the received signal strength in the vicinity of the building is not included in the radio wave information, the received signal strength at the position of the building is estimated by interpolation or the like using the surrounding received signal strength. Thus, the calculation of the received signal strength more accurately in the building can be realized.

In the calculation device according to the present invention, the radio wave information and the calculation result by the calculation unit are used to estimate the range where the radio wave from the wave source reaches, and to output the range estimated by the range estimation unit And an output unit.
With such a configuration, for example, the reach of radio waves can be estimated.

  According to the calculation device and the like according to the present invention, it is possible to know the signal strength of radio waves in a building.

The block diagram which shows the structure of the calculation apparatus by Embodiment 1 of this invention. The flowchart which shows operation | movement of the calculation apparatus by the embodiment The flowchart which shows operation | movement of the calculation apparatus by the embodiment The flowchart which shows operation | movement of the calculation apparatus by the embodiment The flowchart which shows operation | movement of the calculation apparatus by the embodiment The figure which shows the structure of the information communication system containing the calculation apparatus by the embodiment The figure which shows an example of the building information in the embodiment The figure for demonstrating an example of the building location information in the embodiment The figure which shows an example of the change according to the frequency of the shield characteristic by the partition of the building in the embodiment The figure for demonstrating calculation of the signal strength in the building in the embodiment The figure for demonstrating calculation of the signal strength in the building in the embodiment The figure which shows an example of the attenuation characteristic function in the same embodiment The figure for demonstrating specification of the signal strength of the electromagnetic wave in the position of the building in the embodiment The figure for demonstrating estimation of the signal strength of the electromagnetic wave in the position of the building in the embodiment The figure which shows an example of the reachable range and white space in the embodiment The figure which shows an example of the reachable range and white space in the embodiment The block diagram which shows another example of a structure of the calculation apparatus by the embodiment Schematic diagram showing an example of the appearance of the computer system in the embodiment The figure which shows an example of a structure of the computer system in the embodiment

  Hereinafter, a calculation apparatus according to the present invention will be described using embodiments. In the following embodiments, components and steps denoted by the same reference numerals are the same or equivalent, and repetitive description may be omitted.

(Embodiment 1)
A calculation apparatus according to Embodiment 1 of the present invention will be described with reference to the drawings. The calculation device according to the present embodiment calculates the signal strength of radio waves in a building using the frequency characteristics of radio waves shielded by a building partition.

  FIG. 1 is a block diagram showing a configuration of a calculation apparatus 1 according to the present embodiment. The calculation device 1 according to the present embodiment includes a reception unit 11, a radio wave information storage unit 12, a building information storage unit 13, a calculation unit 14, a range estimation unit 15, and an output unit 16.

  The accepting unit 11 accepts radio wave information to be described later and accumulates it in the radio wave information storage unit 12. The accepting unit 11 may accept information other than the radio wave information. The reception unit 11 may receive radio wave information input from an input device (for example, a keyboard, a mouse, a touch panel, etc.), for example, and receive radio wave information transmitted via a wired or wireless communication line. Alternatively, radio wave information read from a predetermined recording medium (for example, an optical disk, a magnetic disk, a semiconductor memory, etc.) may be received. The reception unit 11 may or may not include a device (for example, a modem or a network card) for reception. The receiving unit 11 may be realized by hardware, or may be realized by software such as a driver that drives a predetermined device.

The radio wave information storage unit 12 stores radio wave information. The radio wave information is information having the frequency of the radio wave transmitted from the wave source and information on the intensity of the radio wave. The information on the strength of the radio wave is information that allows the reception signal strength at the position of the building to be known for the radio wave from the wave source. For example, the transmission power of the radio wave transmitted from the wave source and the position of the wave source Well, it may be the reception position of the radio wave transmitted from the wave source, the received signal strength of the radio wave received at the reception position, the transmission power of the radio wave transmitted from the wave source, and the position of the wave source. A plurality of sets of received radio wave reception positions and received signal strengths of radio waves received at the reception positions may be used. The radio wave information may include other information necessary for knowing the received signal strength at the location of the building. The information may be, for example, the height of the transmission antenna.
Storage in the radio wave information storage unit 12 may be temporary storage in a RAM or the like, or may be long-term storage. The radio wave information storage unit 12 can be realized by a predetermined recording medium (for example, a semiconductor memory, a magnetic disk, an optical disk, etc.).

  The building information storage unit 13 stores one or more pieces of building information. The building information is information including building position information indicating the position of the building and frequency characteristics of radio waves shielded by the partition of the building. The building position information may be information indicating the pinpoint position of the building, or may be information indicating the shape of the building together with the position of the building. The information indicating the position of the pinpoint may be, for example, latitude and longitude, or may be a coordinate value based on a certain position. The same applies to other positions. The information indicating the shape of the building may be information indicating the shape of the building in a two-dimensional plane as shown in FIG. 4B, for example, and information on the height direction of the building (for example, the height of the building, the building It may also be information indicating the shape of each height. The building partition may be, for example, an outer wall or window of a building, a wall of a room, or the like. In the present embodiment, the case where the partition of the building is the outer wall of the building will be mainly described. The frequency characteristic of the radio wave shielded by the building partition indicates the radio wave shielding amount or the radio wave attenuation amount for each frequency by the building partition. That is, it is possible to know the degree to which radio waves of a certain frequency are shielded (attenuated) by the building partition by the frequency characteristics. Therefore, when the received signal strength outside a building at a certain frequency is known, the received signal strength inside the partition of the radio wave is calculated by using the frequency characteristics of the radio wave shielded by the partition of the building. It will be possible.

  The process in which building information is memorize | stored in the building information storage part 13 is not ask | required. For example, building information may be stored in the building information storage unit 13 via a recording medium, and building information transmitted via a communication line or the like is stored in the building information storage unit 13. Alternatively, the building information input via the input device may be stored in the building information storage unit 13. The storage in the building information storage unit 13 may be a temporary storage in a RAM or the like, or a long-term storage. The building information storage unit 13 can be realized by a predetermined recording medium (for example, a semiconductor memory, a magnetic disk, an optical disk, etc.).

  Note that the radio wave information storage unit 12 and the building information storage unit 13 may be realized by the same recording medium or may be realized by separate recording media. In the former case, the area that stores the radio wave information is the radio wave information storage unit 12, and the area that stores the building information is the building information storage unit 13.

  The calculation unit 14 uses the radio wave information stored in the radio wave information storage unit 12 and the building information stored in the building information storage unit 13 to calculate the received signal intensity in the building of the radio wave transmitted from the wave source. calculate. When there are a plurality of buildings, the calculation unit 14 may calculate the received signal strength in the building for each building. Strictly speaking, the received signal strength in the building is the received signal strength in the space surrounded by the partition of the building. First, the calculation unit 14 calculates the received signal strength of the radio wave from the wave source at the position of the building using the radio wave information and the building information. The received signal strength of the radio wave from the wave source at the building position is the received signal strength outside the building at the building location. Various methods for calculating the received signal strength at the position of the building will be described later.

Next, the calculation unit 14 uses the frequency of the radio wave included in the radio wave information, the frequency characteristic of the radio wave shielded by the building partition, and the received signal strength of the radio wave at the building position calculated as described above. The received signal strength after the radio signal received signal strength at the building position is attenuated by the building partition, that is, the received signal strength in the building is calculated. Specifically, the calculation unit 14 uses the frequency characteristic of the radio wave shielded by the building partition included in the building information to reduce the attenuation of the radio wave corresponding to the frequency of the radio wave from the wave source included in the radio wave information. Specify the degree. The degree of attenuation of the radio wave indicates the degree to which the radio wave is attenuated by the building partition, and may be, for example, the amount of radio wave shielding or the amount of radio wave attenuation. Thereafter, using the degree of attenuation of the radio wave and the received signal strength of the radio wave at the building position, calculation unit 14 calculates the received signal strength of the radio wave in the building. Specifically, when the received signal strength of the radio wave at the i-th building position is P _{rx, i} (dBm) and the shield amount (attenuation amount) at the i-th building is SH _i (dB). , The received signal strength P _{rxin, i} (dBm) of the radio wave in the i-th building is expressed by the following equation.
P _{rxin, i} = P _{rx, i} −SH _i
Therefore, the calculation part 14 can calculate the received signal strength of the radio wave in each building using the above formula.

  Next, a method for calculating the received signal strength at the building position by the calculation unit 14 will be described. (1) When a predetermined attenuation characteristic is used, (2) When the calculated attenuation characteristic is used, (3) When the received signal strength included in the radio wave information is used as the received signal strength at the building position, (4 A description will be given separately for the case where the received signal strength estimated from the received signal strength included in the radio wave information is the received signal strength at the building position.

(1) When a predetermined attenuation characteristic is used In this case, the radio wave information stored in the radio wave information storage unit 12 includes the frequency of the radio wave transmitted from the wave source and the transmission power of the radio wave transmitted from the wave source. And the position of the wave source. The transmission power is usually antenna power including the influence of the gain of the transmission antenna. The same applies to the following description.

The calculation unit 14 calculates the received signal strength at the building position using the radio wave information and the building position information and a predetermined radio wave attenuation characteristic as follows. P _{rx, i} is the received signal strength (dBm) at the position of the i-th building, P _tx is the transmission power (dBm) of the radio wave from the wave source, and F (x _i , f) is It is a function (hereinafter also referred to as “attenuation characteristic function”) indicating the attenuation characteristic of a radio wave having a propagation distance of x _i (km) and a frequency of f (MHz). The attenuation characteristic is a characteristic of propagation loss (path loss). Further, the propagation distance x _i that is an argument of the attenuation characteristic function F (x _i , f) is the distance from the wave source to the i-th building, and the position of the wave source included in the radio wave information and the i-th building information It can be calculated using the building location information included. Further, the frequency included in the radio wave information is used as the frequency f that is an argument of the attenuation characteristic function F (x _i , f).
P _{rx, i} = P _tx -F (x _i , f)

Here, the case where the attenuation characteristic function F (x _i , f) is expressed as in the following equation will be described, but this need not be the case. However, a is a distance attenuation coefficient, b is a frequency characteristic coefficient, and c is another coefficient. These coefficients are determined according to the model to be adopted, as will be described later.
F (x _i , f) = a × Log (x _i ) + b × Log (f) + c
Here, the coefficients a, b, and c in the case of the free space model, the ground wave two-wave model, and the Okumura-Kashiwa model will be described.

[Free space model]
In the case of a free space model, the coefficients a, b, and c may be set as follows.
a = b = 20
c = 32.44

[Two-wave model of ground reflection]
In the case of a two-wave model of ground reflection, the coefficients a, b, and c may be set as follows.
(A) 1000 × For ^{_{x i <2 1/2 × kh b}} h m a = b = 20
c = 20.4
(B) 1000 × _x ^i> For ^{_{2 1/2 × kh b h m a}} = 40
b = 0
c = 120−20 × Log (h _b h _m )

Here, h _b is the transmitting antenna height (m), and _hm is the receiving antenna height (m). K is a wave number (= 2π / λ = 2πf / c). Note that λ is the wavelength of the radio wave transmitted from the wave source, and c is the propagation speed (light speed). Further, in the case of ^{_{1000 × x i = 2 1/2 ×}} kh b h m is the (A), it may be either (B).

When using two-wave model of the earth reflection, it is necessary to acquire the receive antenna height h _m. The height of the receiving antenna may be, for example, the position in the height direction of the building for calculating the received signal strength, or may be a predetermined value (for example, 10 meters or 20 meters). Good. In addition, if the radio wave information includes the transmission antenna height h _b , that is, the height of the antenna of the wave source, it may be used. If it is not included in the radio wave information, it is determined in advance. A value (eg, 50 meters, etc.) may be used.

[Okumura-Sakai model]
In the case of the Okumura-Kashiwa model, that is, in the case of an urban area model, the coefficients a, b, and c may be set as follows.
a = 44.9−6.55 × Log (h _b )
b = 26.16-1.1 × _h m +1.56
_{c = 69.55-13.82 × Log (h b} ) + 0.7 × h m -0.8

Here, h _b is the transmitting antenna height (m), and _hm is the receiving antenna height (m). Also, this model can be used only when the transmission antenna height h _{b and the} like are in the following range. Note that the reception antenna height and the transmission antenna height may be reversed. That is, h _b may be a receiving antenna height (m), and _hm may be a transmitting antenna height (m).
30 <h _b <200
1 <h _m <10
150 <f <2200
1 <x _i <20
The reception antenna height h _m and the transmission antenna height h _b when using the Okumura-Kashiwa model may be the same as in the case of the two-wave model of ground reflection.

  Here, it will be briefly described which of the three models is used by the calculation unit 14 to calculate the received signal strength at the building position. For example, the calculation unit 14 may set only the free space model from the wave source to each building position and use only the coefficients a, b, and c of the free space model. For example, when each building is arranged so as to be visible (when the calculation target building is a high-rise building, etc.), the free space model from the wave source to the building can be used as such. On the other hand, the calculation unit 14 determines whether there are many high-rise buildings or the like between the wave source and the building by using the position of the wave source, the position of the building, and map information stored in a recording medium (not shown). However, if there are not many high-rise buildings, and it is considered to be a prospect, use a free-space model or a two-wave model of ground reflection, and if there are many high-rise buildings, etc. The Okumura-Kashiwa model may be used. A simple explanation will be given as to whether to select a free space model or a two-wave model of ground reflection when it is considered to be a line of sight. When the receiving antenna height is sufficiently high and the frequency is high, there is no problem even if the free space model is used because the distance to the break point at which the first Fresnel zone begins to be shielded by the ground is large. Otherwise, the effect of shielding the first Fresnel zone cannot be ignored, so it is preferable to use a two-wave model of ground reflection. Therefore, for example, the free space model is adopted when the receiving antenna height at the receiving position (here, the position of the i-th building) is equal to or higher than the threshold value related to the antenna height and the frequency f is equal to or higher than the threshold value related to the frequency. If this is not the case, a two-wave model of ground reflection may be employed. As the reception antenna height, for example, a representative value of the height of the i-th building may be used. The representative value of the height of the building may be, for example, the average of the height of each floor of the building (usually a value obtained by multiplying the height of the building by 0.5). It may be an average height of each floor of the building in consideration of the weight according to the area.

(2) When using the calculated attenuation characteristics In this case, the radio wave information stored in the radio wave information storage unit 12 includes the frequency of the radio wave transmitted from the wave source, the reception position of the radio wave transmitted from the wave source, It is assumed that the received signal strength of the radio wave received at the reception position, the transmission power of the radio wave transmitted from the wave source, and the position of the wave source are included. The radio wave information preferably includes a plurality of sets of reception positions and reception signal strengths.

  Here, a method for obtaining a set of reception position and reception signal strength included in the radio wave information will be briefly described. Such a set may be acquired by the receiving device 3 shown in FIG. 3, for example. The information communication system shown in FIG. 3 includes a calculation device 1, a wave source 2, and a plurality of reception devices 3. The calculation device 1 and the plurality of reception devices 3 include a wired or wireless communication line 100. Connected through. The communication line 100 may be, for example, the Internet, an intranet, a public telephone line network, or the like.

  The receiving device 3 receives radio waves from the wave source 2. The receiving device 3 usually acquires the received signal from the wave source 2 in response to the reception of the radio wave, but this need not be the case. The received signal may be, for example, IQ data of a baseband signal, a complex amplitude value, or the like. When the reception signal is not acquired, the reception device 3 may acquire the reception power of the radio wave from the wave source 2. The receiving device 3 may receive a radio wave of that frequency when it knows the frequency of the radio wave transmitted from the wave source 2, and if it does not know the frequency of the radio wave transmitted from the wave source, Sensing may be performed for a predetermined frequency band. Moreover, when the position of the receiving device 3 is unknown, the receiving device 3 may perform a process of acquiring the position. When the receiving device 3 is movable, it is preferable to perform processing for obtaining the position of the receiving device 3. The number and arrangement location of the receiving devices 3 are not limited, but it is preferable that a sufficient number of receiving devices 3 for estimating the attenuation characteristic function exist as uniformly as possible around the wave source 2. Moreover, although FIG. 3 shows a case where a plurality of receiving apparatuses 3 exist, this need not be the case. Radio waves from the wave source 2 at a plurality of points may be received by one movable receiving device 3. 3 shows a case where the receiving antenna of the receiving device 3 is a parabolic antenna, it goes without saying that this need not be the case.

  When acquisition of the position of the own apparatus is performed by the receiving apparatus 3, the acquisition of the position may be performed using, for example, a GPS (Global Positioning System) or an autonomous navigation apparatus such as a gyro. Alternatively, it may be performed using a nearest base station such as a mobile phone or a wireless LAN, or may be performed by other methods.

In addition, the reception device 3 may calculate a reception signal strength described later using the acquired reception signal and reception power. The received signal strength is the strength (spatial power value) of the radio wave immediately before passing through the receiving antenna of the receiving device 3. Therefore, the received signal strength does not include the influence of the gain of the receiving antenna, and is expressed by the following equation. In the following equation, the reception power is the power of the signal received by the reception device 3 via the reception antenna.
Received signal strength = Received power-Receive antenna gain

  The set of the received signal strength and the reception position transmitted from the reception device 3 may be received by the reception unit 11 of the calculation device 1 and accumulated in the radio wave information storage unit 12. Note that the reception power may be transmitted from the reception device 3, and the reception signal strength may be calculated from the reception power in the calculation device 1. In this case, it is assumed that the calculation device 1 can know the reception antenna gain of each reception antenna. In addition, here, a case has been described in which a set of received signal strength and reception position is transmitted from the receiving device 3, but this need not be the case. The combination of the received signal strength and the receiving position may be received by the receiving unit 11 and stored in the radio wave information storage unit 12 by another method (for example, manually input by the user).

The calculation unit 14 calculates the attenuation characteristic of the radio wave transmitted from the wave source using the radio wave information and the building position information, and calculates the received signal strength at the building position using the calculated attenuation characteristic. Note that calculating the radio wave attenuation characteristic means calculating the radio wave attenuation characteristic function. In addition, when the radio wave attenuation characteristic function F (x _i , f) is expressed by the following equation, the radio wave attenuation characteristic function is calculated by calculating the coefficients a, b, and c of the following equation: It may be. The method will be described below.
F (x _i , f) = a × Log (x _i ) + b × Log (f) + c

The frequency f when calculating the attenuation characteristic function and the frequency f when calculating the received signal strength at the building position are the same frequency of the radio wave transmitted from the wave source. Therefore, the radio wave attenuation characteristic function can be expressed by the following equation. However, a _{c1 = b × Log (f s} ) + c, f s is the radio frequency from the wave source.
F (x _i , f _s ) = a × Log (x _i ) + c1

The relationship between the received signal strength P _{rx, j at} the j-th receiving position, the transmission power P _tx of the radio wave from the wave source, and the attenuation characteristic function F (x _j , f _s ) is as follows: . The distance x _j from the wave source to the jth reception position can be calculated using the position of the wave source included in the radio wave information and the jth reception position. The received signal strength P _{rx, j at} the j-th receiving position and the transmission power P _tx of the radio wave from the wave source are included in the radio wave information. Therefore, the calculation unit 14 can calculate the coefficients a and c1 of the attenuation characteristic function by using, for example, the least square method. The calculated coefficient may be stored in a recording medium (not shown). In this way, the attenuation characteristic function is calculated.
P _{rx, j} = P _tx −F (x _j , f _s )

  In addition, in the receiving device 3, when a sensing result of a certain frequency band is acquired and the sensing result is included in the radio wave information, the calculation unit 14 uses the sensing result to transmit the radio wave transmitted from the wave source. The received signal strength according to the frequency may be specified.

  In the above description, the case where the attenuation characteristic function does not depend on the direction from the wave source (isotropic case) has been described, but this need not be the case. When there are a sufficient number of sets of received signal strengths and receiving positions in each direction, the calculation unit 14 may calculate an attenuation characteristic function for each direction from the wave source. In this case, for example, the azimuth angle from the wave source may be θ, and the coefficients a and c1 of the attenuation characteristic function may be calculated for each range of the azimuth angle θ. Specifically, using a set of the reception position and the received signal strength included in the range of the azimuth angle θ in the range of 0 to 30 degrees (deg), the attenuation characteristic function corresponding to the range of the azimuth angle (that is, the coefficient a , C1), and the attenuation characteristic function may be calculated for all ranges of the azimuth angle θ every 30 degrees. Note that the azimuth angle may be, for example, an azimuth angle with the wave source as the center and 0 degrees north and 90 degrees east. It goes without saying that the range of the azimuth angle may be every angle other than 30 degrees.

  Moreover, the calculation part 14 calculates the received signal strength in a building position using the attenuation characteristic function calculated as mentioned above. The method is the same as in the case of (1) except that the calculated attenuation characteristic function is used, and the description thereof is omitted. When the attenuation characteristic function is calculated for each azimuth angle range, the calculation unit 14 calculates the received signal strength at the building position using the attenuation characteristic function corresponding to the azimuth angle of the building position. .

  In addition, the transmission power of the radio wave transmitted from the wave source included in the radio wave information and the position of the wave source may be information set using the license law of the wave source, or the reception position or reception It may be information estimated from the signal strength. In the latter, a method for estimating transmission power and the like based on the reception position and the like will be described later.

(3) When the received signal strength included in the radio wave information is the received signal strength at the building position In this case, the radio wave information stored in the radio wave information storage unit 12 includes the frequency of the radio wave transmitted from the wave source, It is assumed that a reception position of a radio wave transmitted from a wave source and a plurality of sets of received signal strengths of radio waves received at the reception position are included. The receiving positions are preferably present as evenly as possible around the wave source.

  The calculation unit 14 specifies the received signal strength at the building position using the radio wave information and the building position information. That is, the calculation unit 14 selects the received signal strength at the building position from the received signal strength included in the radio wave information. In the specification, it is preferable to specify the received signal strength similar to the building position. Therefore, for example, the calculation unit 14 may specify a reception position in the vicinity of the building position, and specify the reception signal strength of the radio wave received at the reception position as the reception signal strength at the building position. Specifically, as shown in FIG. 6A, an area for receiving radio waves from a wave source may be divided into a plurality of cells, and each cell may include one reception position. The reception position is indicated by a triangular figure. When the cell C101 includes a building identified by the building ID “B101” (hereinafter, referred to as “building B101”. The same applies to other building IDs), the calculation unit 14 May specify the received signal strength of the receiving position R101 included in the same cell C101 as the received signal strength at the position of the building B101. In FIG. 6A, the case where the region is divided into a plurality of cells has been described, but this need not be the case. The calculation unit 14 may specify the received signal strength corresponding to the reception position closest to a certain building position as the received signal strength at the building position.

(4) When the received signal strength estimated from the received signal strength included in the radio wave information is used as the received signal strength at the building position Also in this case, the radio wave stored in the radio wave information storage unit 12 as in (3) above It is assumed that the information includes multiple sets of the frequency of the radio wave transmitted from the wave source, the reception position of the radio wave transmitted from the wave source, and the received signal strength of the radio wave received at the reception position. . The receiving positions are preferably present as evenly as possible around the wave source.

  The calculation unit 14 estimates the received signal strength at the building position using the radio wave information and the building position information. That is, the calculation unit 14 estimates the received signal strength at the building position by, for example, interpolation or extrapolation using the received signal strength included in the radio wave information. In the estimation, it is preferable to specify the received signal strength near the building position and estimate using the received signal strength. Therefore, for example, the calculation unit 14 identifies a plurality of reception positions in the vicinity of the building position, and uses the received signal strength of the radio wave received at those reception positions to interpolate or extrapolate at the building position. The received signal strength may be estimated. Specifically, as shown in FIG. 6B, the area for receiving the radio wave from the wave source is divided into a plurality of cells, and a reception position may be included in some cells. In FIG. 6B, the reception position is indicated by a triangular figure. Further, in FIG. 6B, it may be considered that the cells are divided into smaller cells than in FIG. 6A. Since the reception position is not included in the cell C202 including the building B201, the calculation unit 14 sets the reception signal strength at the position of the building B201 to the reception positions R201 and R202 of the adjacent cells C201 and C203, respectively. The average of the corresponding received signal strengths may be calculated. For example, when estimating the received signal strength at the position of the building B202, the calculation unit 14 receives received signals corresponding to the receiving positions R201 and R203 of the cells C201 and C207 adjacent to the cell C204 in which the building B202 is included. An average intensity may be calculated. For example, when estimating the received signal strength at the position of the building B203, the calculation unit 14 receives the receiving positions R201, R202, R203 of the cells C201, C203, C207, C209 adjacent to the cell C205 including the building B203. , R204, the average of the received signal strengths corresponding respectively. When the position of a building exists in a cell where the reception position exists (for example, cell C201), the calculation unit 14 determines the received signal strength at the position of the building as in (3) above. You may identify the received signal strength corresponding to the receiving position contained in the same cell. Although the case where the interpolation is to calculate the average has been described here, the interpolation using the distance between the position of the building and a plurality of reception positions may be performed. Specifically, when the distances from the position of a certain building to the two reception positions are L1 and L2, the calculation unit 14 calculates the received signal intensity corresponding to each of the two reception positions. , L1: L2 may be estimated as the received signal strength at the position of the building (linear interpolation). Moreover, although the case where the interpolation was performed was demonstrated here, you may perform an extrapolation. Moreover, although FIG. 6B demonstrated the case where the area | region was divided | segmented into the some cell, it may not be so. The calculation unit 14 specifies a plurality of reception positions in order from a certain building position, and uses the received signal strength corresponding to the plurality of reception positions to calculate the received signal strength at the building position by interpolation, extrapolation, or the like. It may be estimated. The plurality of reception positions may be, for example, two reception positions, or three or more reception positions. In addition, when the distance between the reception position closest to a certain building position and the building position is closer than a predetermined threshold, the calculation unit 14 calculates the received signal strength corresponding to the reception position as the building position. It is good also as receiving signal strength in.

The range estimation unit 15 uses the radio wave information and the calculation result by the calculation unit 14 to estimate the range in which the radio wave from the wave source reaches. The range may be, for example, a range where radio waves from a wave source can be used, or a range affected by radio waves from the wave source. When the wave source is a mobile phone base station, for example, the former range is a range in which a mobile phone call can be made, and the latter range may not be able to make a mobile phone call. It may be in a range where radio waves having a frequency cannot be used for other purposes. In addition, when it can be considered that the area | region other than this range is a white space, the range estimation part 15 can also be considered that the white space is substantially estimated. The white space is a regional area where radio waves from the wave source do not reach. In the case of (1) and (2) above, the range estimation unit 15 uses a predetermined attenuation characteristic or a threshold value with which the received signal power is predetermined using the attenuation characteristic calculated by the calculation unit 14, for example. The distance from the wave source to be calculated may be calculated, and a region connecting the arrival ends of the radio waves that are points according to the distance may be set as a range where the radio waves reach. Specifically, when the attenuation characteristic function is shown in FIG. 5C, the position of the distance d at which the received signal strength becomes the threshold value P ^TH may be set as the radio wave arrival end. Even in a building that is closer to the wave source than the position of the distance d, if the received signal strength calculated by the calculation unit 14 is smaller than the threshold value ^PTH , the building is in a range where radio waves do not reach. In the cases (3) and (4), the range estimation unit 15 determines that a cell having a received signal strength larger than the threshold value P ^TH is a cell in the reachable range, and a white space for a cell that is not so. It may be a cell. Even in a building included in a cell in the reachable range, if the received signal strength calculated by the calculation unit 14 is smaller than the threshold ^PTH , the building is in a range where radio waves do not reach. In the case of (4) above, since there is a cell whose received signal strength is unknown, the received signal strength can be calculated for that cell by interpolation or extrapolation of the received signal strength of a neighboring cell. Good.

  Moreover, the range estimation part 15 may perform separately the process which specifies a white space. When there is only one wave source, as described above, it is possible to specify the white space as a result by specifying the reach range of radio waves, but if there are multiple wave sources, The area where radio waves from the wave source do not reach is white space. Therefore, the range estimation unit 15 may specify a white space that is an area that is not included in any radio wave reachable range. As a result, as long as it is possible to distinguish the radio wave reachable range and white space from the other radio wave reachable areas and white spaces, there is no limitation on the method for specifying the radio wave reachable range or white space. For example, the range estimation unit 15 may acquire information indicating the outline of a region such as a radio wave reachable range.

  The output unit 16 performs output related to the range estimated by the range estimation unit 15. The output may be, for example, outputting information indicating a radio wave reachable range or white space, or outputting a determination result as to whether a certain position is included in the radio wave reachable range or white space. It may be. In the case of outputting the determination result, for example, the output unit 16 may make a determination using the estimation result by the range estimation unit 15, or another component may make the determination. Note that the position to be determined may be received by the receiving unit 11, for example.

  Here, the output may be, for example, display on a display device (for example, a CRT or a liquid crystal display), transmission via a communication line to a predetermined device, printing by a printer, or output to a recording medium. It may be accumulated or delivered to another component. The output unit 16 may or may not include a device that performs output (for example, a display device or a transmission device). The output unit 16 may be realized by hardware, or may be realized by software such as a driver that drives these devices.

  Next, operation | movement of the calculation apparatus 1 is demonstrated using the flowchart of FIG. 2A-FIG. 2D. 2A to 2D are flowcharts showing the operation of the calculation apparatus 1 when calculating the received signal strength at the building position by the methods (1) to (4), respectively.

First, the flowchart of FIG. 2A will be described. In this flowchart, as described above, the received signal strength at the building position is calculated by the method (1).
(Step S101) The calculation unit 14 sets the counter i to 1.

  (Step S102) The calculation unit 14 calculates the received signal strength at the position indicated by the building position information included in the i-th building information by the method (1). The received signal strength may be stored in a recording medium (not shown).

  (Step S103) The calculation unit 14 uses the received signal strength calculated in step S102, the frequency included in the radio wave information, and the frequency characteristics included in the i-th building information to receive the signal in the i-th building. Calculate the signal strength. The received signal strength may be stored in a recording medium (not shown).

  (Step S104) The calculation unit 14 increments the counter i by one.

  (Step S105) The calculation unit 14 determines whether or not the i-th building information exists. If the i-th building information exists, the process returns to step S102; otherwise, the process proceeds to step S106.

  (Step S <b> 106) The range estimation unit 15 estimates the reach of radio waves using the calculation result obtained by the calculation unit 14. The radio wave reachable range as the estimation result may be stored in a recording medium (not shown).

  (Step S <b> 107) The output unit 16 performs output related to the range estimation result by the range estimation unit 15. Then, a series of processes relating to estimation of the reach of radio waves ends.

  Note that white space may be detected in step S106 of the flowchart of FIG. 2A. Further, although this flowchart does not include a process for receiving transmission power or the like, it goes without saying that the reception unit 11 may receive transmission power or the like and store it in the radio wave information storage unit 12.

  Next, the flowchart of FIG. 2B will be described. In this flowchart, as described above, the received signal strength at the building position is calculated by the method (2). The processes other than step S201 are the same as those in the flowchart of FIG. 2A, and a description thereof will be omitted.

(Step S201) The calculation unit 14 calculates attenuation characteristics of the radio wave transmitted from the wave source using the radio wave information. Information indicating the attenuation characteristic, for example, the attenuation characteristic function, the coefficient of the attenuation characteristic function, and the like may be stored in a recording medium (not shown).
In step S102, the received signal strength at the building position is calculated using the attenuation characteristic calculated in step S201.

  Next, the flowchart of FIG. 2C will be described. In this flowchart, as described above, the received signal strength at the building position is calculated by the method (3). The processes other than step S301 are the same as those in the flowchart of FIG. 2A, and a description thereof will be omitted.

(Step S301) The calculation unit 14 uses the radio wave information and the building position information, and is transmitted from the wave source at the position indicated by the building position information included in the i-th building information as described in (3) above. Specify the received signal strength of radio waves. The received signal strength may be stored in a recording medium (not shown).
In step S103, the received signal strength in the building is calculated using the received signal strength calculated in step S301.

  Next, the flowchart of FIG. 2D will be described. In this flowchart, as described above, the received signal strength at the building position is calculated by the method (4). The processes other than steps S401 and S402 are the same as those in the flowchart of FIG. 2A, and a description thereof will be omitted.

  (Step S401) The calculation unit 14 uses the radio wave information and the building position information to specify a reception position close to the position indicated by the building position information included in the i-th building information as described in (4) above. . The specified reception position may be stored in a recording medium (not shown).

(Step S402) The calculation unit 14 calculates the received signal strength at the position indicated by the building position information included in the i-th building information, using the received signal strength corresponding to the receiving position specified in step S401. The calculated received signal strength may be stored in a recording medium (not shown). In addition, when the calculation unit 14 specifies one reception position in step S401, the reception signal intensity corresponding to the reception position is set to the reception signal at the position indicated by the building position information included in the i-th building information. If two or more reception positions are specified in step S401, the i-th building information is obtained by interpolation or extrapolation using a plurality of reception signal intensities corresponding to the two or more reception positions. You may estimate the received signal strength in the position which the building position information contained in shows.
In step S103, the received signal strength in the building is calculated using the received signal strength calculated in step S402.

  Next, operation | movement of the calculation apparatus 1 by this Embodiment is demonstrated using a specific example. In this specific example, the received signal strength at the building position is calculated by the method (2). In the radio wave information storage unit 12, the frequency of the radio wave transmitted from the wave source, the transmission power of the radio wave, the position of the wave source, the reception position of the radio wave transmitted from the wave source, and the radio wave received at the reception position It is assumed that a plurality of sets of received signal strengths are stored.

  Further, it is assumed that the building information storage unit 13 stores the building information shown in FIG. 4A. 4A, the building ID for identifying the building, the building position information indicating the position of the building identified by the building ID, and the frequency of the radio wave shielded by the partition of the building identified by the building ID. The characteristic is associated. The building position information is information such as latitude / longitude and other coordinates indicating the position. Further, the frequency characteristic is information in which a frequency and a degree of shielding at the frequency are associated with each other as shown in FIG. 4C, for example. FIG. 4C shows the shield characteristic (dB) in a predetermined frequency band. If the shield characteristic corresponding to a certain frequency is SH (dB), the radio wave of that frequency is attenuated by SH (dB) by passing through the building partition.

  First, the calculation unit 14 calculates an attenuation characteristic function every 30 degrees from the azimuth angle θ = 0 degrees to 330 degrees from the wave source using the reception position, the received signal strength, the position of the wave source, and the like (step S201). . At that time, the calculation unit 14 calculates the attenuation characteristic function of the azimuth angle θ as a reception position included in a range of 30 degrees from θ-15 degrees to θ + 15 degrees, and a received signal intensity corresponding to the reception position. Shall be used to calculate.

Thereafter, the calculation unit 14 calculates the received signal strength at the building position and the received signal strength in the building in order from the first building information shown in FIG. 4A. Specifically, first, the calculation unit 14 uses the building position information (X101, Y101) of the building B101 and the position of the wave source, the azimuth angle θ of the position of the building B101, and the distance from the wave source to the building B101. d is calculated. Here, it is assumed that the azimuth angle θ is in the range of 285 degrees ≦ θ <315 degrees. Then, the calculation unit 14 reads the attenuation characteristic function corresponding to the azimuth angle of 300 degrees, and specifies the received signal strength at the distance d from the wave source (step S102). Moreover, the calculation part 14 specifies the grade (dB) of the shield corresponding to the frequency of the electromagnetic wave transmitted from the wave source using the frequency characteristic F101 of the shield corresponding to the building B101. Then, the calculation unit 14 calculates the reception signal strength P _B101 inside the building B101 by calculating the reception signal strength obtained by subtracting the specified degree of shielding from the reception signal strength at the distance d from the wave source (step S1). S103). For example, as shown in FIG. 5A, when the received signal strength P _B101 is smaller than the threshold value P ^TH , the radio wave from the wave source does not reach inside the building B101. On the other hand, for example, as shown in FIG. 5B, when the received signal strength P _B101 is larger than the threshold value P ^TH , the radio wave from the wave source has reached the inside of the building B101. In FIGS. 5A and 5B, the degree of shielding of the partition of building B101 is indicated by a double arrow. Thereafter, the calculation unit 14 repeatedly executes the same processing for other buildings (steps S102 to S105).

When the received signal strengths in all buildings are calculated, the range estimation unit 15 specifies the distance d at which the received signal strength is the threshold value ^PTH for each attenuation characteristic function, as shown in FIG. 5C. The position of the distance d is the arrival end of the radio wave. 7A and 7B are diagrams illustrating an example of the position of the radio wave reachable range. The boundary of the radio wave arrival range may pass through each of the radio wave arrival ends as shown in FIG. 7A, or may not be as shown in FIG. 7B. In the latter case, for example, the range estimation unit 15 uses a set of the specific azimuth angle θ and the distance d acquired (θ, d) is plotted. And what corresponds to the curve specified so that the distance between the plotted point and the curve may be the closest may be the boundary line of the radio wave reachable range. The radio wave arrival distance is the distance from the wave source to the radio wave arrival end. For each building, whether or not radio waves reach the building is determined separately as described above. The determination may also be made by the range estimation unit 15. For example, for the buildings B101 and B106, it is assumed that the received signal strength in the building is smaller than the threshold value ^PTH even if the building position is included in the radio wave reachable range. Then, as shown in FIG. 7A and the like, the buildings B101 and B106 become white spaces. On the other hand, for example, for the buildings B103 and B104, it is assumed that the received signal strength in the building is larger than the threshold value ^PTH . Then, as shown in FIG. 7A and the like, buildings B103 and B104 are included in the radio wave reachable range. In addition, for a building outside the reachable range, that is, in a white space, the received signal strength at that position is smaller than the threshold value P ^TH , so the received signal strength in the building is also smaller than the threshold value P ^TH . For this reason, for example, the reach range of the radio wave from the wave source may be specified, and the received signal strength in the building may be calculated only for the buildings included in the range.

  In this specific example, the case where the position of the building is indicated by the position of the pinpoint has been described, but this need not be the case. For example, the building position information of the building B101 may also indicate the shape of the building. In that case, as shown in FIG. 4B, the building position information includes information (X101-1, Y101-1), (X101-2, Y101-2),. X101-6, Y101-6). In that case, for example, it becomes possible to indicate more precisely whether or not the image is included in the white space.

  As described above, according to the calculation device 1 according to the present embodiment, it is possible to know the received signal strength of radio waves in a building. As a result, it is possible to determine whether the interior of a building is white space, and to determine whether communication within the same frequency as the radio wave transmitted from the wave source can be performed separately. You can also. For example, even if a building's partition is shielded about the frequency of radio waves transmitted from the wave source, whether the building is white space is determined according to the proximity to the wave source and the degree of shielding. There is. In such a case, it becomes possible to know whether or not the inside of the building is a white space by using the calculation device 1. In addition, even if there is a change in the wave source, for example, a change in transmission power, a change in radio wave frequency, a change in the position of the wave source, etc. You can easily know if it is space.

  A method for estimating transmission power and the like based on the reception position and the like will be described. When performing such processing, as shown in FIG. 8, the calculation apparatus 1 further includes a wave source calculation unit 18 that calculates the position of the wave source and the transmission power based on the reception position and the received signal strength. May be.

  First, a method by which the wave source calculation unit 18 specifies the position of the wave source will be described. The wave source calculation unit 18 calculates the position of the wave source 2 specified using radio waves from the wave source 2 received by the plurality of receiving devices 3. Here, as a method by which the wave source calculation unit 18 calculates the position of the wave source 2, a calculation method by TDoA (Time Difference of Arrival) and a calculation method by DoA (Direction of Arrival) will be described. The position of the wave source 2 may be calculated by other methods.

[Calculation method using TDoA]
In this case, the radio wave information storage unit 12 stores the reception signal received from the wave source, the reception time (reception time) of the reception signal, and the reception position of the reception signal for three or more reception positions. It shall be. Therefore, in this case, the reception unit 11 may also receive the reception signal received from the wave source at the reception position and the reception time point together with the reception position and the like, and store the reception signal in the radio wave information storage unit 12. The wave source calculation unit 18 calculates the position of the wave source using the reception signals corresponding to the plurality of reception positions, the reception time points of the reception signals, and the plurality of reception positions stored in the radio wave information storage unit 12. Specifically, the wave source calculation unit 18 calculates the time difference at which the same radio wave transmitted from the wave source arrives at the reception position using the cross-correlation of the reception signals received at three or more reception positions. The wave source calculation unit 18 can calculate the time difference using the reception time point. Further, the wave source calculation unit 18 calculates a propagation distance difference from the wave source to a plurality of reception positions by multiplying the time difference by the speed of the radio wave (the speed of light). A curve with a constant difference in distance from a certain position is a hyperbola. Accordingly, the distance from the wave source to the receiving position R301, when the difference between the distance from the wave source to the receiving position R302 is _{L ab,} the wave source, a receiving position R301, and two focus a receiving position R302 It will be located on the hyperbola. Note that the difference between each distance from the point on the hyperbola to the two focal points is _Lab . In the case of using observation data transmitted from three reception positions, the wave source calculation unit 18 can specify a hyperbola for the combination of the other two reception positions in the same manner. You may calculate the position of the wave source 2 by calculating the intersection of a hyperbola. For details of the position calculation method by TDoA, refer to the following document, for example.
Literature: K. Ho, Y. Chan, “Solution and performance analysis of geolocation by tdoa”, IEEE Transactions on Aerospace and Electronic Systems, vol. 29, no. 4, p. 1311-1322, October 1993

[Calculation method by DoA]
In this case, the radio wave information storage unit 12 stores the direction of the wave source and the reception position for two or more reception positions. Therefore, in this case, the reception unit 11 may receive the direction of the wave source at the reception position as well as the reception position and the like, and store the reception direction in the radio wave information storage unit 12. In addition, in order to acquire the direction of a wave source, it is preferable that the receiving device 3 can change the directivity of radio wave reception. The directivity change may be made physically, for example, by rotating the directional antenna, or may be made electronically, such as by changing the directivity in the phased array antenna. The wave source calculation unit 18 calculates the position of the wave source using the direction of the wave source acquired at the plurality of reception positions and the plurality of reception positions stored in the radio wave information storage unit 12. In addition, when a certain reception position and the direction of the wave source from there are known, the wave source exists on a straight line passing through the position and extending in the direction. Therefore, the wave source calculation unit 18 can identify two straight lines by knowing the two reception positions and the direction of the wave source from each reception position, and the position of the wave source 2 that is the intersection of the straight lines. Can be calculated. In this case, it is preferable that the two reception positions and the position of the wave source do not exist on the same straight line. For details of the position calculation method using DoA, refer to the following document, for example.
Reference: SU Pillai, "Array Signal Processing", Springer-Verlag, 1989

  In addition, the wave source calculation unit 18 may calculate the position of the wave source using all the reception positions, or may calculate the position of the wave source using a part of the reception positions. In the latter case, for example, the wave source calculation unit 18 may calculate the position of the wave source by TDoA using the three reception positions having the highest received signal strength of the radio wave from the wave source, The position of the wave source may be calculated by DoA using any two of the reception positions. Further, the wave source calculation unit 18 may store the calculated position of the wave source in a recording medium (not shown). When the wave source calculation unit 18 does not calculate the position of the wave source, for example, the position of the wave source may be calculated by TDoA or DoA as described above by a device other than the calculation device 1.

Next, a method in which the wave source calculation unit 18 calculates the transmission power of the wave source will be described. The wave source calculation unit 18 estimates the transmission power of the wave source using the received signal strength included in the radio wave information and the distance from the wave source to the reception position. Note that the distance from the wave source to the reception position can be calculated using the position of the wave source calculated as described above and the reception position included in the radio wave information. The relationship between the transmission power P _tx and the received signal strength P _{rx, j} at the j-th receiving position is expressed by the following equation as described in (1) above. F (x _j , f) is an attenuation characteristic function corresponding to the distance x _j from the wave source to the j-th receiving position and the frequency f of the radio wave transmitted from the wave source.
P _{rx, j} = P _tx −F (x _j , f)

Further, when a model to be employed (for example, a free space model, a ground wave two-wave model, an Okumura-Hagi model, etc.) is determined, an attenuation characteristic function corresponding to the model is determined. Thus, its damping characteristic function, the distance x _i from the wave source to the i th reception position, by using the received signal strength at frequency f and i-th receiving position included in the radio wave information, the transmission power P _tx Can be calculated.

Here, a method for determining a model to be adopted will be briefly described. For example, the wave source calculation unit 18 may set only the free space model from the wave source to each reception position, and may use only the free space model. For example, in the case where each reception position is arranged so as to be visible, it is possible to use a free space model for everything from the wave source to the reception position. On the other hand, the wave source calculation unit 18 determines whether or not there is a line of sight from the wave source to the reception position using the amount of time variation of the received signal power and the delay profile. A model may be used, and the Okumura-Kashiwa model may be used when it is not a prospect. A method for determining whether the line of sight is out of sight or not using the delay profile is already known, and detailed description thereof is omitted. For example, the delay profile used in the determination may be generated by the wave source calculation unit 18 using a received signal (IQ signal data) included in the radio wave information, or the delay profile itself is included in the radio wave information. Also good. In the latter case, for example, the reception unit 11 may also receive the delay profile generated by the reception device 3 or the like and store it in the radio wave information storage unit 12. Incidentally, in the case not expected, Okumura - if that does not meet the above range h _b such a condition using the Hata model, for example, may be used a different propagation model. In addition, as described in the above (1), whether to select a free space model or a two-wave model of ground reflection when it is determined that the line of sight is determined using the delay profile, for example, The reception antenna height at the i-th reception position and the frequency f may be compared with a threshold value.

By calculating the transmission power as described above, the transmission power of the wave source is calculated for each reception position. Therefore, a method for estimating a single transmission power from the plurality of transmission powers will be described. Here, as a method for calculating the final transmission power P _tx from a plurality of transmission powers P _{tx, j} calculated using the above equation, a method using a maximum value and a method for performing statistical processing will be described. To do.

[Method using maximum value]
The wave source calculation unit 18 may set the maximum value among the calculated transmission powers P _{tx, j} as the final transmission power P _tx . Usually, it is considered that the transmission power calculated using the reception power received through the propagation path which is an ideal line of sight becomes the maximum value. Therefore, it is considered that the transmission power can be set to a more accurate value by setting the maximum value of the transmission power as the transmission power P _tx of the estimation result. Note that the transmission power P _tx may be the result of adding a positive value margin M to the maximum value. In this case, the estimated transmission power P _tx is, for example, as follows.
P _tx = max {P _{tx, j} } + M

[How to perform statistical processing]
The wave source calculation unit 18 may calculate a maximum value of a plurality of transmission powers by performing statistical processing, and may use the calculated maximum value as a final transmission power P _tx . Specifically, the wave source calculation unit 18 calculates the average E and the standard deviation σ of the transmission power {P _{tx, j} } using the calculated plurality of transmission powers P _{tx, j} . The wave source calculation unit 18 may set E + 3σ as the transmission power P _tx . By doing so, the maximum value of the transmission power considering the statistical variation can be used as the transmission power estimation result P _tx .

  Moreover, although this Embodiment mainly demonstrated the case where the partition which shields an electromagnetic wave was an outer wall of a building, it may not be so. For example, when the wall of a room is a partition that shields radio waves, the received signal strength inside the room may be calculated. Then, it may be determined whether or not the inside of the room is within the reach of radio waves. Further, in a single building, when the frequency characteristics of the partition are different for each room, for example, the calculation unit 14 may calculate the received signal strength in the building for each room, The range estimation unit 15 may determine whether each room is within the reach of radio waves or whether it is a white space.

  In addition, depending on the method of calculating the received signal strength at the building position, the received signal strength may differ depending on the height of the received position (for example, when a two-wave model of ground reflection or the Okumura-Sakai model is used). In such a case, when the building position information includes height information for each floor of the building, the received signal strength at the building position may be calculated for each floor of the building. .

  Moreover, although this Embodiment demonstrated the case where the calculation apparatus 1 was provided with the range estimation part 15, it may not be so. When it is only necessary to know the received signal strength in the building, the calculation device 1 may not include the range estimation unit 15. In that case, the output unit 16 may output the calculation result by the calculation unit 14.

  In the present embodiment, the case where the radio wave information storage unit 12 stores radio wave information related to one radio wave has been described, but this need not be the case. The radio wave information storage unit 12 may store radio wave information related to two or more radio waves. In that case, for each radio wave, calculation of the received signal strength in the building, estimation of the reach of the radio wave, and the like may be performed.

  In addition, it is considered that the frequency characteristics related to radio wave shielding by the partition are usually determined by the structure of the partition (for example, material, thickness, rebar spacing, etc.). Therefore, frequency characteristics corresponding to a plurality of structures of the partition are prepared in advance. For example, in the frequency characteristics shown in FIG. 4A, a frequency characteristic close to a predetermined frequency characteristic is set. Also good. By doing so, there is an advantage that it is not necessary to measure frequency characteristics for each partition.

  Further, in the present embodiment, the case has been described in which the range estimation unit 15 obtains the reach of radio waves outside the building and determines whether the inside of the building is the reach of radio waves. Good. The range estimation unit 15 may perform only the latter process, that is, determination of whether or not radio waves from the wave source have reached the building (determination of whether the building is a white space).

  In the above embodiment, each process or each function may be realized by centralized processing by a single device or a single system, or may be distributedly processed by a plurality of devices or a plurality of systems. It may be realized by doing.

  In the above embodiment, the information exchange between the components is performed by one component when, for example, the two components that exchange the information are physically different from each other. It may be performed by outputting information and receiving information by the other component, or when two components that exchange information are physically the same, one component May be performed by moving from the phase of the process corresponding to to the phase of the process corresponding to the other component.

  In the above embodiment, information related to processing executed by each component, for example, information received, acquired, selected, generated, transmitted, or received by each component In addition, information such as threshold values, mathematical formulas, addresses, and the like used by each constituent element in processing may be temporarily or for a long time held in a recording medium (not shown), even if not specified in the above description. Further, the storage of information on the recording medium (not shown) may be performed by each component or a storage unit (not shown). Further, reading of information from the recording medium (not shown) may be performed by each component or a reading unit (not shown).

  In the above embodiment, when information used by each component, for example, information such as a threshold value, an address, and various setting values used by each component may be changed by the user, Even if it is not specified in the description, the user may be able to change the information as appropriate, or may not be so. If the information can be changed by the user, the change is realized by, for example, a not-shown receiving unit that receives a change instruction from the user and a changing unit (not shown) that changes the information in accordance with the change instruction. May be. The change instruction received by the receiving unit (not shown) may be received from an input device, information received via a communication line, or information read from a predetermined recording medium, for example. .

  Moreover, in the said embodiment, when two or more components included in the calculation apparatus 1 have a communication device, an input device, etc., two or more components may have a physically single device. Or you may have separate devices.

  In the above-described embodiment, each component may be configured by dedicated hardware, or a component that can be realized by software may be realized by executing a program. For example, each component can be realized by a program execution unit such as a CPU reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory. At the time of execution, the program execution unit may execute the program while accessing the storage unit or the recording medium. In addition, the software which implement | achieves the calculation apparatus 1 in the said embodiment is the following programs. That is, this program includes a radio wave information storage unit that stores radio wave information including information on the frequency of radio waves transmitted from the wave source and the intensity of the radio waves, building position information that indicates the position of the building, and building partitions. Using a radio wave information and a building information, a computer that can access a building information storage unit that stores building information including the frequency characteristics of the radio wave shielded by the radio wave is received in the building using the radio wave information and the building information. It is a program for making it function as a calculation part which calculates signal strength.

  In the program, the functions realized by the program do not include functions that can be realized only by hardware. For example, functions that can be realized only by hardware such as a modem or an interface card in an acquisition unit that acquires information, an output unit that outputs information, and the like are not included in at least the functions realized by the program.

  Further, this program may be executed by being downloaded from a server or the like, and a program recorded on a predetermined recording medium (for example, an optical disk such as a CD-ROM, a magnetic disk, a semiconductor memory, or the like) is read out. May be executed by Further, this program may be used as a program constituting a program product.

  Further, the computer that executes this program may be singular or plural. That is, centralized processing may be performed, or distributed processing may be performed.

  FIG. 9 is a schematic diagram showing an example of the external appearance of a computer that executes the program and realizes the calculation apparatus 1 according to the embodiment. The above-described embodiment can be realized by computer hardware and a computer program executed on the computer hardware.

  In FIG. 9, the computer system 900 includes a computer 901 including a CD-ROM drive 905, a keyboard 902, a mouse 903, and a monitor 904.

  FIG. 10 is a diagram showing an internal configuration of the computer system 900. In FIG. 10, in addition to the CD-ROM drive 905, a computer 901 is connected to an MPU (Micro Processing Unit) 911, a ROM 912 for storing a program such as a boot-up program, and the MPU 911. A RAM 913 that temporarily stores and provides a temporary storage space, a hard disk 914 that stores application programs, system programs, and data, and a bus 915 that interconnects the MPU 911, the ROM 912, and the like are provided. The computer 901 may include a network card (not shown) that provides connection to a LAN, WAN, or the like.

  A program that causes the computer system 900 to execute the function of the calculation apparatus 1 according to the above-described embodiment may be stored in the CD-ROM 921, inserted into the CD-ROM drive 905, and transferred to the hard disk 914. Instead, the program may be transmitted to the computer 901 via a network (not shown) and stored in the hard disk 914. The program is loaded into the RAM 913 when executed. The program may be loaded directly from the CD-ROM 921 or the network. Further, the program may be read into the computer system 900 via another recording medium (for example, a DVD) instead of the CD-ROM 921.

  The program does not necessarily include an operating system (OS), a third party program, or the like that causes the computer 901 to execute the function of the calculation device 1 according to the above-described embodiment. The program may include only a part of an instruction that calls an appropriate function or module in a controlled manner and obtains a desired result. How the computer system 900 operates is well known and will not be described in detail.

  Further, the present invention is not limited to the above-described embodiment, and various modifications are possible, and it goes without saying that these are also included in the scope of the present invention.

  As described above, according to the calculation device and the like according to the present invention, the effect that the signal intensity of the radio wave in the building can be obtained is obtained, and for example, it is useful as a device for detecting white space including in the building.

DESCRIPTION OF SYMBOLS 1 Calculation apparatus 2 Wave source 3 Receiving apparatus 11 Reception part 12 Radio wave information storage part 13 Building information storage part 14 Calculation part 15 Range estimation part 16 Output part 18 Wave source calculation part

Claims (8)

A radio wave information storage unit that stores radio wave information having a frequency of a radio wave transmitted from the wave source and information on the intensity of the radio wave;
A building information storage unit that stores building information including building position information indicating the position of the building and frequency characteristics of radio waves shielded by the partition of the building;
A calculation device comprising: a calculation unit that calculates the received signal strength of the radio wave transmitted from the wave source in the building using the radio wave information and the building information. The radio wave information has a transmission power of a radio wave transmitted from the wave source, and a position of the wave source,
The calculation unit calculates the received signal strength of the radio wave at the position of the building using the radio wave information and the building position information and a predetermined radio wave attenuation characteristic, and the received signal strength and the frequency characteristic The calculation apparatus according to claim 1, wherein the received signal strength in the building is calculated using the frequency of the radio wave. The radio wave information includes a reception position of a radio wave transmitted from the wave source, a received signal intensity of the radio wave received at the reception position, a transmission power of the radio wave transmitted from the wave source, and a position of the wave source. And
The calculation unit calculates attenuation characteristics of a radio wave transmitted from the wave source using the radio wave information and the building position information, calculates a received signal strength at the building position, and calculates the received signal strength, the frequency The calculation device according to claim 1, wherein the received signal strength in the building is calculated using characteristics and the frequency of the radio wave. The radio wave information has a plurality of sets of reception positions of radio waves transmitted from the wave source and received signal strengths of radio waves received at the reception positions,
The calculation unit uses the radio wave information and the building position information to identify a received signal strength at the building position, and uses the received signal strength, the frequency characteristic, and the frequency of the radio wave to The calculation device according to claim 1, wherein the reception signal strength at is calculated. The radio wave information has a plurality of sets of reception positions of radio waves transmitted from the wave source and received signal strengths of radio waves received at the reception positions,
The calculation unit estimates the received signal strength at the position of the building using the radio wave information and the building position information, and uses the received signal strength, the frequency characteristics, and the frequency of the radio wave to estimate the inside of the building. The calculation device according to claim 1, wherein the reception signal strength at is calculated. A range estimation unit that estimates a range where radio waves from the wave source reach using the radio wave information and a calculation result by the calculation unit;
The calculation device according to claim 1, further comprising: an output unit that performs output related to the range estimated by the range estimation unit. Radio wave information stored in a radio wave information storage unit that stores radio wave information including the frequency of radio waves transmitted from a wave source and information related to the intensity of the radio wave, building position information indicating the position of the building, and the building The received signal in the building of the radio wave transmitted from the wave source using the building information stored in the building information storage unit in which the building information including the frequency characteristics of the radio wave shielded by the partition is stored A calculation method comprising a calculation step for calculating intensity. Shielded by a radio wave information storage unit that stores radio wave information including the frequency of the radio wave transmitted from the wave source and information on the intensity of the radio wave, building position information indicating the position of the building, and a partition of the building A computer that can access a building information storage unit that stores building information including frequency characteristics of radio waves,
The program for functioning as a calculation part which calculates the received signal strength in the building of the radio wave transmitted from the wave source using the radio wave information and the building information.

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