JP2019009803A - Reception strength calculation device, reception strength calculation method, program - Google Patents

Abstract

To provide a technique for calculating reception strength accurately, while taking account of measurement accuracy of an actual measurement value.SOLUTION: In a reception strength calculation device, an actual measurement value acquisition unit 62 acquires an actual measurement value of reception strength, when receiving radio waves transmitted from an origination point at a plurality of respective actual measurement points. A theoretical value acquisition unit 60 acquires a theoretical value of reception strength at a reception point corresponding to each of the actual measurement values of a plurality of reception strength acquired by the actual measurement value acquisition unit. A derivation unit 38 derives difference between the actual measurement value of reception strength and the theoretical value of reception strength, at each actual measurement point, on the basis of a plurality of actual measurement values of reception strength, and a plurality of theoretical values of reception strength. An object point theoretical value acquisition unit 64 acquires the theoretical value of reception strength at a reception point becoming an object of reception strength calculation. A correction unit 36 performs correction for the theoretical value of reception strength acquired by the object point theoretical value acquisition unit, on the basis of the difference at each actual measurement point.SELECTED DRAWING: Figure 8

Description

The present invention relates to a reception strength acquisition technique, and more particularly to a reception strength calculation apparatus, a reception strength calculation method, and a program that use theoretical values and actual measurement values.

In mobile phone systems and commercial wireless systems, it is required to display the reception status of radio waves transmitted from the base station device in an easy-to-understand manner for each area. For example, by collecting radio field intensity, location information, time, etc. from the terminal device, and overlaying these on map information,
The actual radio wave condition at a certain point is confirmed from a point different from that point. At that time, the theoretical value of radio wave propagation is corrected by the actually measured value. Furthermore, if the distance from the actual measurement point is small,
Correction to a value close to the actual measurement value is made, and if the distance from the actual measurement point is large, correction to a value close to the theoretical value is made (for example, see Patent Document 1).

International Publication No. 10/067560 Pamphlet

By creating a map of radio wave reception status, the user can intuitively grasp the radio wave status at an arbitrary point. However, the accuracy of this map depends on the number of points from which measured values are obtained, and many measurement points are required to create a highly accurate map. Some actual measurement values have high measurement accuracy and some measurement accuracy is low, and the accuracy of the map varies depending on the measurement accuracy of the actual measurement values.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique for accurately calculating reception intensity in consideration of measurement accuracy of actual measurement values.

  In order to solve the above problems, a reception intensity calculation device according to an aspect of the present invention includes a target point theoretical value acquisition unit that acquires a theoretical value of reception intensity at a target point that is a target for calculating radio wave reception intensity; An actual value acquisition unit that acquires an actual value of received intensity at one or more actual measurement points located within a predetermined distance from the target point, a theoretical value acquired by the target point theoretical value acquisition unit, and the actual value acquisition A correction unit that calculates a correction value of the received intensity at the target point using the actual measurement value acquired by the unit, and the correction unit determines the number of actual measurement values acquired by the actual measurement value acquisition unit. Accordingly, the correction value is calculated by changing the influence of the actually measured value.

  Another aspect of the present invention is a reception strength calculation method. This method includes a step of obtaining a theoretical value of reception intensity at a target point for which radio wave reception intensity is calculated, and measurement of reception intensity at one or more measurement points located within a predetermined distance from the target point. A calculation step of calculating a correction value of received intensity at the target point using the theoretical value and the actual measurement value, and in the calculation step, the number of the actual measurement values is calculated. Accordingly, the correction value is calculated by changing the influence of the actually measured value.

It should be noted that any combination of the above-described constituent elements and a conversion of the expression of the present invention between a method, an apparatus, a system, a recording medium, a computer program, etc. are also effective as an aspect of the present invention.

  According to the present invention, it is possible to accurately calculate the reception intensity in consideration of the measurement accuracy of the actual measurement value.

It is a figure which shows the structure of the communication system which concerns on Example 1 of this invention. It is a figure which shows the structure of the receiving strength calculation apparatus of FIG. It is a figure which shows the outline | summary of the process in the determination part of FIG. It is a figure which shows the relationship between the difference hold | maintained in the determination part of FIG. 2, and a correction range. It is a flowchart which shows the output procedure of the map by the receiving intensity calculation apparatus of FIG. It is a figure which shows the outline | summary of the acquisition process of the receiving strength which concerns on Example 2 of this invention. It is a flowchart which shows the correction | amendment procedure by the receiving intensity calculation apparatus which concerns on Example 2 of this invention. It is a figure which shows the structure of the receiving strength calculation apparatus which concerns on Example 3 of this invention. It is a figure which shows the outline | summary of the acquisition process of the receiving strength by the receiving strength calculation apparatus of FIG. It is a figure which shows the relationship between the number of receiving points hold | maintained in the determination part of FIG. 8, and W (N). FIGS. 11A and 11B are diagrams illustrating correction values calculated by the correction unit in FIG. It is a flowchart which shows the output procedure of the map by the receiving intensity calculation apparatus of FIG. It is a figure which shows the structure of the receiving strength calculation apparatus which concerns on Example 4 of this invention. It is a figure which shows the relationship between the dispersion | variation degree hold | maintained in the determination part of FIG. 13, and Q (V). FIGS. 15A and 15B are diagrams illustrating correction values calculated by the correction unit in FIG. It is a flowchart which shows the output procedure of the map by the receiving intensity calculation apparatus of FIG.

Example 1
Before describing the present invention specifically, an outline will be given first. Embodiment 1 of the present invention relates to a communication system in which a reception intensity calculation device is wired to a base station device wirelessly connected to a terminal device. It is important for a telecommunications carrier to grasp the radio wave condition within the coverage. Especially in urban areas, there are many shielding objects such as buildings, and it is desirable to consider the influence on the radio wave condition in advance. This is because, in a low power environment, when the user of the terminal device performs communication, there is a possibility that the quality of communication may deteriorate. In addition, grasping such a weak power environment is useful for improving the radio wave condition such as installing a base station device at an appropriate position. Furthermore, the terminal device is used not only in an urban area but also in a region with many undulations such as a mountain or a village away from a daily living area.

On the other hand, a model that theoretically calculates received power (reception strength) of a terminal device based on the positional relationship between the base station device and the terminal device is known. For example, the Okumura-Kashiwa model that takes distance attenuation, shielding loss, and diffraction loss into consideration. By using such a theoretical model, it is possible to predict the radio wave condition in a wide area with a relatively small number of steps and a small cost. However, the theoretical model is an approximation of the real world to the last, and the calculation accuracy of the radio wave condition is not necessarily high. On the other hand, if the radio wave condition at each point is actually measured, a high-accuracy radio wave condition map can be created, but it requires a very large number of man-hours and a large cost. Therefore, in the reception strength calculation device according to the present embodiment, the measured value of the radio wave condition is collected from the terminal device that has actually started operation, and the theoretical value of the reception strength calculated using the theoretical model and a limited number Effectively create highly accurate radio wave condition maps by effectively using the actual measured values.

For example, the reception strength calculation device sets the theoretical value of the reception strength so that the influence of the actual measurement value increases as the distance from the point where the actual measurement value is obtained, and the influence of the actual measurement value decreases as the distance increases. to correct. Further, the reception intensity calculation device determines a correction range around the measurement point and a correction range in which the theoretical value should be corrected based on the difference between the actual measurement value and the theoretical value of the reception intensity. .

FIG. 1 shows a configuration of a communication system 100 according to Embodiment 1 of the present invention. Communication system 10
0 includes the reception intensity calculation device 10, the map DB 12, the network 14, the base station device 16, and the terminal device 18. The network 14, the base station device 16, and the terminal device 18 constitute a mobile phone system and a commercial wireless system. Since the network 14, the base station device 16, and the terminal device 18 included in these systems are well-known techniques, description thereof is omitted here. In FIG. 1, a point where the base station device 16 is installed (hereinafter referred to as “transmission point”) is indicated as “T”, and a point where the terminal device 18 exists (hereinafter referred to as “measurement point”) is “ P ". Here, the radio wave is actually transmitted from the transmission point, and the radio wave is actually received at the actual measurement point. In addition, the location that is expected to receive radio waves from the point of origin (hereinafter referred to as “the point of reception”)
“Q1” to “Q13” are indicated. Although omitted in FIG. 1, a reception point is also set as an actual measurement point.

The terminal device 18 measures the reception intensity of the radio wave received at the actual measurement point, and transmits the actual measurement value of the reception intensity to the base station device 16. The reception strength calculation device 10 is connected to the base station device 16 via the network 14 and receives an actual measurement value of the reception strength from the terminal device 18. On the other hand, the reception intensity calculation device 10 calculates a theoretical value of the reception intensity when a radio wave from a transmission point is received at each reception point. Further, the reception intensity calculation device 10 corrects the theoretical value at the reception point arranged in the vicinity of the actual measurement point based on the received actual measurement value. The range of the reception point where the theoretical value is corrected is called “correction range”. The reception intensity calculation device 10 generates a radio wave state map by combining the theoretical value at each reception point and the corrected theoretical value with the geographic information data acquired from the map DB 12.

FIG. 2 shows a configuration of the reception strength calculation apparatus 10. The reception intensity calculation device 10 includes a geographic information data acquisition unit 20, a radio wave condition calculation unit 22, and a geographic information data / radio wave condition synthesis unit 26. The radio wave condition calculation unit 22 includes a first acquisition unit 30, a second acquisition unit 32, a determination unit 34, and a correction unit 36.

The geographic information data acquisition unit 20 is connected to the map DB 12 and acquires geographic information data in the coverage from the map DB 12. In the geographical information data, for each reception point where the reception intensity is to be calculated, the position information (latitude, longitude) and the altitude H in consideration of the antenna height of the terminal device 18
m information is included. For example, the reception point may be set on a main road, a building, or the like. The geographic information data includes location information (latitude, longitude) of the transmission point and information about the antenna height Hb of the terminal device 18.

The first acquisition unit 30 calculates a theoretical value of the reception intensity when the radio wave transmitted from the transmission point of the geographic information data is received at each of the plurality of reception points. The theoretical value of the reception intensity at the reception point Q1 on the geographic information data is indicated as S [Q1]. Other reception points are also shown in the same manner. Furthermore, the theoretical value of the reception intensity at the reception point corresponding to the actual measurement point P on the geographic information data is indicated as S [P]. For example, the Okumura-Kashiwa model is used to calculate the theoretical value of the reception intensity in the first acquisition unit 30.

The second acquisition unit 32 is connected to the network 14 (not shown) and receives an actual measurement value of the received intensity from the base station device 16. The second acquisition unit 32 also acquires position information of a reception point where an actual measurement value of reception intensity is measured. That is, the second acquisition unit 32 uses the reception point corresponding to one of the plurality of reception intensity theoretical values acquired by the first acquisition unit 30 as the actual measurement point, and calculates the actual measurement value of the reception intensity at the actual measurement point. get. The measured value of the received intensity at the measured point P is R
[P] is indicated.

The determination unit 34 determines the difference between the measured value R [P] of the received intensity acquired by the second acquiring unit 32 and the theoretical value S [P] of the received intensity at the measured point acquired by the first acquiring unit 30, for example. Then, an absolute value difference (| S [P] −R [P] |) is calculated. When the difference between the theoretical value and the actual measurement value is large, there is a high possibility that the influence of local factors (a specially shaped building, local noise generation, etc.) is large. Here, in order to reduce these local influences when correcting the theoretical value of the received strength, the determination unit 34 increases the size of the variable correction range according to the difference between the theoretical value of the received strength and the measured value. To decide. FIG. 3 shows an outline of processing in the determination unit 34. Base station device 16
The terminal device 18, the transmission point, the reception point, and the actual measurement point are shown in the same manner as in FIG. In FIG.
A circular area having a radius r centered on the actual measurement point “P” where the terminal device 18 is located is a correction range 50.
As shown. As described above, the size of the correction range 50 is determined by the determination unit 34.

FIG. 4 shows the relationship between the difference held in the determination unit 34 and the correction range. The horizontal axis indicates the absolute value difference (| S [P] −R [P] |), and the vertical axis indicates the radius r of the correction range 50. As illustrated, the radius r increases as (| S [P] -R [P] |) decreases. When the difference is small, it is considered that the influence of local factors is small, and the correction range 50 is set wide. on the other hand,
The radius r decreases as (| S [P] -R [P] |) increases. If the difference is large,
The correction range 50 is set to be narrow considering that the influence of local factors is great. Returning to FIG. When determining the size of the correction range 50, the determination unit 34 refers to the relationship illustrated in FIG. 4 and determines the radius r of the correction range 50 so that the correction range 50 is increased as the difference is reduced. .
Here, the theoretical value of the reception intensity at the reception point included in the correction range 50 is a correction target. In the case where the actually measured value is smaller than the theoretical value, the influence of the shielding loss due to the building and the interference caused by the radio waves transmitted from other wireless devices is large. On the other hand, when the measured value is larger than the theoretical value, the shielding loss due to the building is reduced.

The correction unit 36 corrects the theoretical value of the reception intensity at the reception point included in the correction range 50 determined by the determination unit 34 based on the actual measurement value of the reception intensity acquired by the second acquisition unit 32. Execute. More specifically, the reception intensity E [x] at the reception point x within the correction range 50 of the radius r centered on the actual measurement point P is expressed as in Expression (1). The reception strength E [x] corresponds to a correction result of the theoretical value of the reception strength.

In Expression (1), k1 [x] and k2 [x] are coefficients determined by the reception point x and satisfy the condition of Expression (2).

Further, k2 [x] has a monotonously decreasing characteristic that decreases as the distance between the actual measurement point P and the reception point x increases, and is expressed by an exponential function, for example.

In Equation (1) and Equation (2), for example, when k1 [x] = 1 and k2 [x] = 0, this corresponds to using only theoretical values. In that case, the information of the actual measurement value R [P] is not considered at all. Therefore, when correcting the reception intensity at each reception point within the radius r from the actual measurement point P, the correction unit 36 increases the influence of the actual measurement value R [P] as the point is closer to the actual measurement point P. The farther from the point P, the greater the influence of the theoretical value S [x]. By performing such correction, it is possible to prevent a sudden change in reception intensity even when the number of measurement points is small, and a highly accurate radio wave situation map that changes smoothly is created. .

The geographic information data / radio wave condition combining unit 26 creates a radio wave condition map by superimposing the received intensity acquired by the radio wave condition calculating unit 22 on the geographic information data acquired by the geographic information data acquiring unit 20. Here, the reception strength superimposed on the geographic information data corresponds to a theoretical value of the reception strength and a correction result of the theoretical value of the reception strength. Further, the geographic information data / radio wave condition combining unit 26 outputs the generated radio wave condition map to a screen display device (not shown).

The configuration of the reception intensity calculation device 10 is, in terms of hardware, a CPU of an arbitrary computer,
It can be realized by a memory or other LSI, and in terms of software, it is realized by a program loaded in the memory. Here, functional blocks realized by their cooperation are depicted. Accordingly, those skilled in the art will understand that these functional blocks can be realized in various forms by hardware only, software only, or a combination thereof.

The operation of the reception strength calculation apparatus 10 having the above configuration will be described. FIG. 5 is a flowchart illustrating a map output procedure performed by the reception intensity calculation apparatus 10. The geographic information data acquisition unit 20 acquires geographic information data (S10). The first acquisition unit 30 calculates a theoretical value (S12
). The second acquisition unit 32 acquires actual measurement values (S14). The determination unit 34 calculates the difference (S
16) A correction range is determined (S18). The correction unit 36 performs correction (S20). The geographic information data / radio wave condition synthesis unit 26 synthesizes the geographic information data and the reception intensity (S22),
The map is output (S24).

According to the present embodiment, the correction based on the actual measurement value is executed for the theoretical value, so that the calculation accuracy of the reception strength can be improved. Also, if there is no actual measurement value, a theoretical value is used, so that a radio wave situation map can be created while suppressing an increase in actual measurement cost. In addition, a highly accurate radio wave situation map can be efficiently created from a small number of actually measured values. In addition, the number of terminal devices necessary for creating the radio wave condition map can be reduced, and the cost can be reduced. Further, since the correction range is determined to be larger as the difference between the actual measurement value and the theoretical value is smaller, the reception intensity can be acquired in consideration of the measurement accuracy of the actual measurement value. Further, as the distance from the actual measurement point to the reception point becomes shorter, the influence of the actual measurement value of the reception intensity increases, so that appropriate correction can be performed for each point on the map, and the calculation accuracy of the reception intensity can be improved.
(Example 2)
Next, Example 2 will be described. As in the first embodiment, the second embodiment collects measured values of radio wave conditions from terminal devices that have actually started operation, and has a limited number of theoretical values of received intensity calculated using a theoretical model. The present invention relates to the efficient creation of a highly accurate radio wave situation map by effectively utilizing actual measurement values. In the second embodiment, as in the first embodiment, the size of the correction range is adjusted. On the other hand, the second embodiment corresponds to a process in the case where two actually measured points are close to each other and thus their correction ranges overlap. The communication system 100 and the reception intensity calculation device 10 according to the second embodiment have the same configuration as that shown in FIGS. Here, the difference will be mainly described.

FIG. 6 shows an overview of reception intensity acquisition processing according to Embodiment 2 of the present invention. Here, FIG.
Only the measurement points and reception points in FIG. 3 are shown. Here, the first actual measurement point “P1” and the second actual measurement point “P2” are shown as the actual measurement points. Further, a plurality of reception points “Q1 to Q17” are shown around these actual measurement points.

The second acquisition unit 32 in FIG. 2 performs the first measurement value of the first reception intensity at the first measurement point “P1” and the first
A measured value of the second received intensity at the second measured point “P2” different from the measured point “P1” is acquired. The determination unit 34 receives the theoretical value S [P1] of the reception strength and the actual measurement value R [P1] of the first reception strength.
], The size of the first correction range 52 shown in FIG. 6 is determined. Further, the correction unit 36 receives the theoretical value S [x] of the reception intensity and the actual measurement value R [P1] of the first reception intensity for the reception points included in the first correction range 52 determined by the determination unit 34. Based on the above, a correction value E [x] of the theoretical value of the reception intensity is calculated.

Subsequently, the determination unit 34 determines the size of the second correction range 54 shown in FIG. 6 based on the theoretical value S [P2] of the received intensity and the actually measured value R [P2] of the second received intensity. To decide. Further, the correction unit 36 receives the theoretical value S [x] of the reception intensity and the actual measurement value R [P2] of the second reception intensity for the reception points included in the second correction range 54 determined by the determination unit 34. Based on the above, a correction value E [x] of the theoretical value of the reception intensity is calculated. However, at this time, the first correction range 52 and the second correction range 54
For the reception points Q4, Q5, Q6, and Q7 in the area where and overlap, the theoretical values S [Q4], S [
Instead of Q5], S [Q6], and S [Q7], correction values E [Q4], E [Q5], E [Q6], and E [Q7 of theoretical values of the received intensity calculated in the first correction range 52 are used. ] And the correction value of the theoretical value in the second correction range 54 is calculated by replacing the theoretical value correction values E [Q4], E [Q5], E [in place of S [x] in Equation (1). Q6] and E [Q7] are used. As a result, the first
The correction values of the theoretical values of the reception points Q4, Q5, Q6, and Q7 in the region where the correction range 52 and the second correction range 54 overlap are further corrected. For these calculations, the equations (1) and (2) are used.

FIG. 7 is a flowchart illustrating a correction procedure by the reception intensity calculation apparatus 10 according to the second embodiment of the present invention. The determination unit 34 and the correction unit 36 correct the theoretical value based on the first actually measured value and the theoretical value (S40). The determination unit 34 and the correction unit 36 further correct the corrected theoretical value based on the corrected theoretical value and the second actually measured value (S42). Even when there are three or more actually measured values and their correction ranges overlap, the same processing may be performed.

According to the present embodiment, the theoretical value is corrected by the first actual measurement value, and then the corrected theoretical value is further corrected by the second actual measurement value. Therefore, the two actual measurement points are close to each other. However, the first actual measurement value and the second actual measurement value can be reflected in the theoretical value. In addition, since two actually measured values are used, the accuracy of the reception strength can be improved.
(Example 3)
Next, Example 3 will be described. The third embodiment relates to correcting the theoretical value of the reception intensity based on the actual measurement value of the reception intensity as before. Up to now, the theoretical value of the reception intensity at the reception point included in the correction range is corrected based on the actual measurement value of the reception intensity at the measurement point. on the other hand,
In the third embodiment, the theoretical value of the received intensity at the point (target point) where the received intensity is calculated is corrected based on the measured values of the received intensity at a plurality of measured points in the vicinity of the target point. Execute. At this time, in order to improve the accuracy of the correction, the correction is performed so that the influence of the actual measurement value is changed according to the number of the actual measurement values.

FIG. 8 shows the configuration of the reception strength calculation apparatus 10 according to the third embodiment of the present invention. The reception intensity calculation device 10 includes a geographic information data acquisition unit 20, a radio wave condition calculation unit 22, and a geographic information data / radio wave condition synthesis unit 26. The radio wave condition calculation unit 22 includes a theoretical value acquisition unit 60, an actual measurement value acquisition unit 62, a determination unit 34, a correction unit 36, a derivation unit 38, and a target point theoretical value acquisition unit 64.

The actual measurement value acquisition unit 62 acquires the actual measurement value of the reception intensity when the radio wave transmitted from the transmission point is received at each of the plurality of actual measurement points. The theoretical value acquisition unit 60 includes a theoretical value acquisition unit 60.
The theoretical value of the reception intensity at the reception point corresponding to each of the plurality of actual measurement values of the reception intensity acquired in step S1 is acquired. Here, it is assumed that the theoretical values at the actual measurement points can be acquired without any exception.

FIG. 9 shows an outline of reception strength acquisition processing by the reception strength calculation apparatus 10. Here, it is assumed that the target point for the theoretical value correction process is “target point” x. The target point x may be an actual measurement point, but in the following description, the target point x is not an actual measurement point, and an actual measurement value of reception intensity is not acquired. Next, an actual measurement point where an actual measurement value is obtained is specified in the vicinity of the target point x. For example, an actual measurement point whose distance from the target point x is within a predetermined value or less is specified. In FIG. 9, the range where the distance from the target point x is a predetermined value or less is the calculation range 5
It is shown as 6. The actual measurement points included in the calculation range 56 are indicated as Q1 to Q12. If the number of actual measurement points included in the calculation range 56 is large, N actual measurement points may be selected in order of increasing distance from the target point x, and the remaining actual measurement points may be ignored. In the following, in order to generalize the description, QN that is the Nth actual measurement point is used instead of Q12. The theoretical values at the actual measurement points Q1 to QN are indicated as S [Q1] to S [QN], and the actual measurement values are R [Q1] to R [Q
N]. Further, the distance from the target point x to the points Q1 to QN is set to D [Q1] to D [Q.
N]. Returning to FIG.

The deriving unit 38 has a plurality of measured values R [Q1] of a plurality of reception strengths acquired by the measured value acquiring unit 62.
˜R [QN] and the theoretical values S [Q1] of the plurality of reception strengths acquired by the theoretical value acquisition unit 60
Based on S [QN], the difference Δ [Q1] between the measured value of the received strength and the theoretical value of the received strength
Δ [QN] is derived for each measured point. For example, Δ [Q1] = R [Q1] −S [Q1].

The determination unit 34 determines the coefficient W (N) in accordance with the number of actually measured reception strength values acquired by the actual value acquisition unit 62, that is, the number of actual measurement points included in the calculation range 56 of FIG. . Here, W (N) is a function having the number N of actual measurement points as an input. FIG. 10 shows the relationship between the number of actually measured points held in the determination unit 34 and the coefficient W (N). The horizontal axis indicates the number N of actual measurement points, and the vertical axis indicates the coefficient W (N). For example, the coefficient W (N) has such characteristics that the smaller the N, the smaller the output and the larger the N, the larger the output. In this example, the output value of the coefficient W (N) is in the range of 0-1. Note that the minimum value of the coefficient W (N) may be a value greater than 0 instead of 0, and the maximum value of the coefficient W (N) may be a value greater than 1. Returning to FIG.

The target point theoretical value acquisition unit 64 acquires the theoretical value of the reception intensity at the target point x. The theoretical value of the reception intensity at the target point is indicated as S [x]. It is assumed that the measured value of the received intensity is not acquired at the target point.

The correction unit 36 receives the theoretical value S [x] of the received intensity acquired by the target point theoretical value acquisition unit 64.
On the other hand, correction based on the differences Δ [Q1] to Δ [QN] for each actual measurement point derived by the deriving unit 38 is executed. In this correction, the radio wave intensity E [x] at the target point x is expressed by Equation (3).
It is equivalent to calculating based on.

Here, α [i] (i = 1 to N) is a distance D [Qi from the target point x to the actual measurement point Qi.
], And has a monotonically decreasing characteristic in which α [i] decreases as D [Qi] increases. When the theoretical value S [x] is corrected in this manner, the influence of the actually measured value becomes strong when the target point x is close to the actually measured point Qi. This corresponds to the large influence of the difference. On the other hand, when the target point x is far from the actual measurement point Qi, the influence of the theoretical value becomes strong. Note that one Qk of the actual measurement points Qi (i = 1 to N) may coincide with the target point x. In this case, D [Qk] = 0, and α [k] takes the maximum value. For this reason, the influence of Qk is greater than that of other measured points Qj (j = 1 to N, j ≠ k), but not only the measured value of Qk but also the measured value of Qj is reflected and the radio field intensity E [X] is calculated.

In addition, when W (N) is included, the number of actually measured values is small (for example, N = 1)
), Since W (N) is small, the reception intensity (correction value) E [x] is calculated that has a small effect on the actual measurement value and a large effect on the theoretical value. Therefore, the correction value is close to the theoretical value S [x] at the target point x. On the other hand, when the number of actually measured values is large (for example, N = 10), W (N) is large. Therefore, the radio field intensity (correction value) E has a large influence of the actually measured value and a small influence of the theoretical value. [X] is calculated. That is, the influence of the difference is adjusted according to the coefficient W (N) corresponding to the number N of actual measurement points existing in the vicinity of the target point x on which the theoretical value is corrected. Here, each actual measurement value includes a measurement error and local factors. When N is large, the error of each actual measurement value can be canceled (averaged), so the influence of the actual measurement value is increased.

11A to 11B show correction values calculated by the correction unit 36. FIG. FIG. 11 (a)
Indicates a case where the number N of actually measured values is small, and FIG. 11B shows a case where the number N of actually measured values is large. In FIGS. 11A to 11B, C1 and C3 are correction values when W (N) is not used, and correspond to processing when W (N) = 1 is fixed in equation (3). . In this state, the theoretical value TH is corrected regardless of the number of actually measured values. C2 is a correction value according to the equation (3) when the number N of actually measured values is small, and is shown to be a value close to the theoretical value TH.
C4 is a correction value according to the equation (3) when the number N of actually measured values is large, and shows that the value is considerably larger than the theoretical value TH.

FIG. 12 is a flowchart illustrating a map output procedure performed by the reception intensity calculation apparatus 10. The geographic information data acquisition unit 20 acquires geographic information data (S60). Theoretical value acquisition unit 6
0 calculates a theoretical value (S62). The actual measurement value acquisition unit 62 acquires actual measurement values (S64).
. The deriving unit 38 calculates the difference (S66). The determination unit 34 determines W (N) (S6
8). The correction unit 36 performs correction (S70). Geographic information data / radio wave condition synthesis unit 26
Combines the geographic information data and the received intensity (S72), and outputs a map (S74).

According to the present embodiment, since the reception intensity at the target point is calculated using a plurality of actual measurement values, the accuracy of the reception intensity can be improved. Further, when the number of actually measured values is small, the correction value is calculated without increasing the influence of the actually measured values, so that the influence of errors included in the actually measured values can be reduced. Further, when there are a large number of actually measured values, variations in the actually measured values can be offset (averaged). Moreover, since the dispersion | variation in an actual measurement value is canceled, a local factor can be canceled. In addition, since the theoretical value is corrected smoothly, a highly accurate radio wave situation map can be created.
(Example 4)
Next, Example 4 will be described. The fourth embodiment relates to correcting the theoretical value of the reception intensity based on the actual measurement value of the reception intensity as before. Further, in the fourth embodiment, as in the third embodiment, the reception intensity at a plurality of measurement points existing in the vicinity of the target point is compared with the theoretical value of the reception intensity at the target point where the theoretical value is corrected. The correction is executed based on the actual measurement value. At this time, in order to improve the accuracy of the correction, correction is performed so as to change the influence of the actual measurement value according to the degree of variation of the actual measurement value existing in the vicinity of the target point x.

FIG. 13 shows the configuration of the reception strength calculation apparatus 10 according to the fourth embodiment of the present invention. The configuration requirements included in the reception intensity calculation device 10 are the same as those in FIG. 8, but some of the connections and functions are different.
The theoretical value acquisition unit 60, the actual measurement value acquisition unit 62, and the derivation unit 38 execute the same processing as in FIG. The determination unit 34 calculates an index V indicating the degree of variation of the differences Δ [Q1] to Δ [QN] for each actual measurement point derived by the deriving unit 38. As index V, variance (sample variance, unbiased variance),
Numerical values such as standard deviation, average deviation, and difference between the third quartile value and the first quartile value can be used.
For example, when the variance is used as the index V, it is calculated according to the equation (4). here,
Δm is an average value of N differences.

The determination unit 34 determines the coefficient Q (V) according to the index V. Here, Q (V) is a function having the index V as an input. FIG. 14 shows the relationship between the degree of variation held in the determination unit 34 and Q (V). The horizontal axis indicates the index V of the variation degree, and the vertical axis indicates the coefficient Q (V
). For example, the coefficient Q (V) has such characteristics that the smaller the V, the larger the output and the larger the V, the smaller the output. In this example, the output value of the coefficient Q (V) is in the range of 0-1. Note that the minimum value of the coefficient Q (V) may be a value larger than 0 instead of 0.
The maximum value of (V) may be larger than 1. Returning to FIG.

The correction unit 36 receives the theoretical value S [x] of the received intensity acquired by the target point theoretical value acquisition unit 64.
On the other hand, correction based on the differences Δ [Q1] to Δ [QN] for each actual measurement point derived by the deriving unit 38 is executed. In this correction, the radio wave intensity E [x] at the target point x is expressed by Equation (5).
It is equivalent to calculating based on.

In addition, when Q (V) is included, when the difference Δ [Qi] at each measurement point has a large degree of variation, since Q (V) is small, the influence of the actual measurement is small and the influence of the theoretical value The reception intensity (correction value) E [x] that increases the force is calculated. That is, the correction value is close to the theoretical value S [x] at the target point x. On the other hand, the difference Δ [
When the degree of variation of Qi] is small, since Q (V) is large, the influence of the actual measurement value is large, and the influence of the theoretical value is reflected in the reception intensity (correction value) E [x].

FIGS. 15A and 15B are diagrams illustrating correction values calculated by the correction unit 36. FIG. FIG.
5A shows a case where the degree of variation of the difference Δ [Qi] is large, and FIG. 15B shows a case where the difference Δ [Qi] is small. In FIGS. 15A to 15B, C5 and C7 are correction values when Q (V) is not used, and correspond to processing when Q (V) = 1 is fixed in equation (5). . In this state, the theoretical value TH is corrected regardless of the number of actually measured values. C6 is a correction value according to the equation (5) when the degree of variation is large, and is shown to be a value close to the theoretical value TH. C8 is a correction value according to the equation (5) when the degree of variation is small, and shows that the value is considerably larger than the theoretical value TH.

That is, the influence of the difference is adjusted according to the coefficient Q (V) corresponding to the degree of variation of the actual measurement value in the vicinity of the target point x where the theoretical value is corrected. Here, when the variation in the actual measurement value is large, it is considered that the measurement error and local factors are large, and it is better not to change the theoretical value greatly. When the variation is small, it is considered that there are few measurement errors and local factors, so the theoretical value may be changed significantly.

FIG. 16 is a flowchart illustrating a map output procedure performed by the reception intensity calculation apparatus 10. The geographic information data acquisition unit 20 acquires geographic information data (S90). Theoretical value acquisition unit 6
0 calculates the theoretical value (S92). The actual measurement value acquisition unit 62 acquires actual measurement values (S94).
. The deriving unit 38 calculates the difference (S96). The determination unit 34 calculates V (S98) and Q
(V) is determined (S100). The correction unit 36 performs correction (S102). The geographic information data / radio wave condition combining unit 26 combines the geographic information data and the received intensity (S104), and outputs a map (S106).

According to the present embodiment, when the variation degree of the difference between the actual measurement value and the theoretical value is large, the correction value is calculated without increasing the influence of the actual measurement value. Can reduce the effects of In addition, when the degree of variation is small, correction is performed so that the influence of the actual measurement value becomes strong, so that the accuracy of the reception intensity can be improved. Moreover, since the theoretical value is smoothly corrected regardless of the degree of variation, a highly accurate radio wave situation map can be created.

In the above, this invention was demonstrated based on the Example. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to the combination of each component and each processing process, and such modifications are also within the scope of the present invention. .

In the fourth embodiment of the present invention, the degree of variation of the difference Δ [i] (i = 1 to N) between the actually measured value and the theoretical value is calculated. However, the present invention is not limited to this. For example, when the area near the target point x is narrow, or when the theoretical value can be regarded as almost constant in the vicinity area, the measured value R [
Qi] (i = 1 to N) may be calculated and used as the index V.
According to this modification, the degree of freedom of configuration can be improved.

DESCRIPTION OF SYMBOLS 10 Reception strength calculation apparatus, 12 Map DB, 14 Network, 16 Base station apparatus, 18 Terminal apparatus, 20 Geographic information data acquisition part, 22 Radio wave condition calculation part,
26 Geographic information data / radio wave condition synthesis unit, 30 first acquisition unit, 32 second acquisition unit,
34 determination unit, 36 correction unit, 38 derivation unit, 40 third acquisition unit, 60 theoretical value acquisition unit, 62 actual measurement value acquisition unit, 64 target point theoretical value acquisition unit, 100 communication system.

Claims (6)

A target point theoretical value acquisition unit for acquiring a theoretical value of reception strength at a target point for which the reception strength of radio waves is to be calculated;
An actual measurement value acquisition unit for acquiring an actual measurement value of reception intensity at one or more actual measurement points located within a predetermined distance from the target point;
A correction unit that calculates a correction value of the reception intensity at the target point using the theoretical value acquired by the target point theoretical value acquisition unit and the actual value acquired by the actual value acquisition unit;
With
The correction unit calculates the correction value by changing the influence of the actual measurement value according to the number of actual measurement values acquired by the actual measurement value acquisition unit. A theoretical value acquisition unit that acquires a theoretical value of received intensity at each of the one or more measurement points;
The correction unit derives a difference between the actual measurement value acquired by the actual measurement value acquisition unit and the theoretical value acquired by the theoretical value acquisition unit for each of the one or more actual measurement points, and derives one or more derived values A first value that aggregates the differences is calculated, a first coefficient that is larger as the number of actual measurement values acquired by the actual measurement value acquisition unit increases, and the first coefficient and the first coefficient are calculated. Adding the product value to the theoretical value acquired by the target point theoretical value acquisition unit to calculate the correction value,
The reception intensity calculation apparatus according to claim 1. The actual measurement value acquisition unit acquires actual measurement values of received intensity at a plurality of actual measurement points located within a predetermined distance from the target point,
The correction unit derives a plurality of differences between the actual measurement value acquired by the actual measurement value acquisition unit and the theoretical value acquired by the theoretical value acquisition unit, and between each of the plurality of actual measurement points and the target point And calculating a weighted average value of the plurality of derived differences as the first value using a second coefficient that becomes larger as the distance is shorter.
The reception intensity calculation apparatus according to claim 2. The correction unit uses the output value when the number of actual measurement values acquired by the actual measurement value acquisition unit is input to a function having a monotonically increasing characteristic as the first coefficient.
The reception intensity calculation device according to claim 2 or claim 3, wherein Obtaining a theoretical value of the reception strength at the target point for which the reception strength of the radio wave is calculated;
Obtaining an actual measurement value of reception intensity at one or more actual measurement points located within a predetermined distance from the target point;
A calculation step of calculating a correction value of the reception intensity at the target point using the theoretical value and the actual measurement value;
Including
In the calculation step, the correction value is calculated by changing the influence of the actual measurement value according to the number of the actual measurement values. Obtaining a theoretical value of the reception strength at the target point for which the reception strength of the radio wave is calculated;
Obtaining an actual measurement value of reception intensity at one or more actual measurement points located within a predetermined distance from the target point;
A calculation step of calculating a correction value of the reception intensity at the target point using the theoretical value and the actual measurement value;
A program for causing a computer to execute
In the calculation step, the correction value is calculated by changing the influence of the actual measurement value according to the number of the actual measurement values.

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