JP6304653B2 - Interference estimation system, wireless device - Google Patents

Description

  The present invention relates to an interference estimation system and a radio apparatus that estimate interference with a radio system using a common or close frequency band.

  Free space available to other users (secondary usage system) without affecting primary users in the frequency band assigned to broadcasting etc. (primary usage system) in order to use frequency resources effectively The practical application of a technology that shares the frequency (white space) of the same channel that has a sufficiently small influence on the channel or the primary use system is being studied. The white space in the UHF band where the primary usage system is a television broadcasting system is called TV white space (TVWS). As a secondary user of TVWS, an area broadcasting system, a specific radio microphone, a sensor network, a wireless LAN, Broadband services such as wireless access systems are being considered.

  When using the TVWS system, it is essential that the secondary usage system does not interfere with the primary usage system. In order to estimate the amount of interference that the secondary usage system gives to the primary usage system, a propagation loss model is required.

  The broadcasting area of the primary usage system is estimated by a method determined by the authorities. However, a method of estimating interference that the secondary usage system gives to the primary usage system when using TVWS is not specifically defined. Therefore, the interference evaluation to the primary usage system given by the secondary usage system is performed by applying free space propagation loss and taking a large margin.

  However, if the conventional interference evaluation method is applied to the secondary usage system as it is, the conditions will be severer, so the secondary usage system is practically very small compared to the primary usage system. The secondary usage system itself cannot be operated. In addition, since the conventional interference evaluation method is based on the premise that the transmitter and the receiver are fixed, it is difficult to realize the secondary usage system as a mobile system.

JP 2011-33583 A JP 2007-81941 A

  As described above, the conventional interference estimation system and the wireless device have problems that it is difficult to operate the secondary usage system and it is difficult to realize the secondary usage system as a mobile system. The present invention has been made in order to solve such a problem, and provides an interference estimation system and a radio apparatus capable of realizing interference evaluation of a secondary usage system and realizing the secondary usage system as a mobile system. The purpose is that.

（ただしL_Iは前記伝搬損失、h_b1は前記送信アンテナの地上高、h_m1は前記受信アンテナの地上高）の演算式に基づき前記送信アンテナおよび前記受信アンテナ間の距離dを算出する距離取得部と、前記送信点の位置情報および前記距離取得部が算出した距離dに基づいて前記第2の無線システムが前記第1の無線システムへ影響を与えない領域の領域情報を生成するマップ生成部とを具備する。 In the interference estimation system of the embodiment, the second radio system that uses the frequency band is lower than the first radio system because the frequency band to be used overlaps or is close to the first radio system and the first radio system uses the second radio system. The interference estimation system for estimating the presence or absence of interference given to the radio system of 1, the transmission position information of the second radio system, transmission frequency information, transmission output information, gain information and ground height information of the transmission antenna, A storage unit for storing gain information and ground height information of the receiving antenna of the second wireless system, and allowable electric field strength information of the radio wave transmitted from the second wireless system allowed from the first wireless system; Based on the transmission output information, the gain information of the transmission antenna, and the allowable electric field strength information, a loss for calculating the minimum propagation loss allowed for the second radio system Using a calculation unit, a propagation loss the loss calculation unit has calculated, the transmission frequency information, the ground clearance information and ground clearance information of the receiving antennas of the transmitting antenna,

(Where L _I is the propagation loss, h _b1 is ground clearance, h _m1 is ground height of the receiving antenna of the transmitting antenna) distance acquisition of calculating the distance d between the transmitting antenna and the receiving antenna based on the arithmetic expression And a map generation unit that generates region information of a region where the second wireless system does not affect the first wireless system based on the position information of the transmission point and the distance d calculated by the distance acquisition unit It comprises.

  ADVANTAGE OF THE INVENTION According to this invention, the interference estimation system and radio | wireless apparatus which can implement | achieve the interference evaluation of a secondary usage system and can implement | achieve a secondary usage system as a mobile system can be provided.

It is a figure explaining a two-wave propagation model. FIG. 6 is a diagram showing a transmission condition and a reception condition in Experiment 1. FIG. 4 is a diagram showing a measurement result of Experiment 1. FIG. 4 is a diagram showing a measurement result of Experiment 1. FIG. 4 is a diagram showing a measurement result of Experiment 1. FIG. 4 is a diagram showing a measurement result of Experiment 1. FIG. 4 is a diagram showing a measurement result of Experiment 1. FIG. 10 is a diagram showing a transmission condition and a reception condition in Experiment 2. FIG. 6 is a diagram showing a measurement result of Experiment 2. It is a figure which shows the propagation model which combined the 2 wave propagation model and the free space propagation model with 6 dB offset. It is a figure which shows the propagation model which combined the 2 wave propagation model and the free space propagation model with 6 dB offset, and a measurement result. It is a figure explaining the influence which the altitude difference of a transmission point and a receiving point gives. It is a figure explaining the propagation model used in the interference estimation system of embodiment. It is a block diagram which shows the structure of the interference estimation system of embodiment. It is a figure which shows an example of topographic information. It is a flowchart which shows operation | movement of the interference estimation system of embodiment. It is a block diagram which shows the structure of the radio | wireless apparatus of embodiment. It is a flowchart which shows operation | movement of the radio | wireless apparatus of embodiment.

(Interference evaluation of secondary usage system)
In order for the secondary usage system to use TVWS, it is a condition that no interference is given to the primary usage system. When the interference area of the secondary usage system (the margin of the service area taken to avoid interference) overlaps with the service area of the primary usage system using the same channel, the secondary usage system uses TVWS. Can not do it. Therefore, the secondary usage system using TVWS needs to grasp its own interference area. The interference area is obtained by connecting points where the electric field strength at a specific point obtained by using its own transmission output power, gain of the transmission antenna, and propagation loss in space becomes a predetermined level at which interference can occur. Can do. In order to obtain the propagation loss in space, it is necessary to define a radio wave propagation model.

  In general, a radio wave propagation model of a wireless system is developed for the purpose of evaluating a service area of a primary usage system, and is intended for a system with a relatively large scale. Specifically, the radio wave propagation model defined in the Ministry of Posts and Telecommunications Notification No. 640 and used for determining the receivable area of a wide-area television broadcasting system has a high transmission antenna height of several tens of meters and a transmission distance of 1 km to A long distance of several tens of kilometers is assumed. The radio wave propagation model that evaluates the primary usage system is intended for systems that can use their own frequency band in preference to others, so the secondary usage system has a lower priority of frequency usage than the primary usage system. It cannot be applied as it is to the evaluation.

  Since the secondary usage system using TVWS is in a position where no interference (interference) should be given to the primary usage system, the scale of the system is originally small. Specifically, the transmission distance of the secondary usage system is a relatively short distance of several kilometers or less, and the antenna height of the base station of the secondary usage system is low (about 10 m or less). For example, the transmission output is 1 W or less, and considering the antenna gain, the ERP can be about 10 W or less. Therefore, it is necessary to formulate a radio wave propagation model for evaluating a secondary usage system under conditions that do not cause interference in the primary usage system, assuming a system scale that does not affect others.

  Based on the above, the radio wave propagation model of the secondary usage system needs to be modeled when the received power is maximized in the line-of-sight environment in order to evaluate a small-scale system with the maximum interference power. In other words, when constructing a radio wave propagation model for the secondary usage system, there should be no influence on the receiver of the primary usage system outside the interference area where the transmission side of the secondary usage system interferes. Evaluation is required when the propagation attenuation from the transmission side of the next-use system is minimized.

(Propagation loss model for line-of-sight environment)
Since the secondary usage system is a relatively small system, a propagation model in a line-of-sight environment is desirable. Under the line-of-sight environment, there are two types of propagation: direct propagation from the transmitting antenna to the receiving antenna and propagation reaching the ground, which can cause interference with each other. growing. Therefore, it seems desirable to use a two-wave model of ground reflection.

ただし、Δlは行路長差であり、λは波長である。 As shown in Fig. 1, the height of the base station antenna (transmitting antenna) from the flat ground is h _b , the height of the mobile station antenna (receiving antenna) is h _m , and the horizontal distance between them is d, and the distance between transmission and reception Is a certain distance, and the propagation loss L _g of the two-wave model when the reflection coefficient is approximated to −1 is expressed by Equation 1.

Where Δl is the path length difference and λ is the wavelength.

The path length difference Δl is expressed by Equation 2.

In the range where Δl> λ / 2, the direct wave and the ground reflected wave interfere with each other and fading occurs, and the average value L _g1 is expressed by Equation 3 where the free space propagation loss is L _f. The

On the other hand, when the distance d increases and enters the region of Δl <λ / 2, the path length difference between the direct wave and the ground reflected wave monotonically approaches 0, so that they cancel each other and rapidly attenuate. Since Equation 4 holds in the region of Δl << λ / 2, the propagation loss L _g2 is expressed by Equation 5.

That is, in the two-wave model, the attenuation changes from an attenuation proportional to d ^{2 of} free space propagation to an attenuation proportional to d ⁴ at a certain distance. This change point is called a breakpoint. The break point can be defined by a point where Δl = λ / 2 at which monotonic decrease starts (Formula 6) or an intersection of Formula 3 and Formula 5 (Formula 7).

すなわち、自由空間伝搬損失は距離の2乗、波長の-2乗に比例することが分かる。 (Propagation loss model as a comparative example)
As models used for radio wave propagation in a relatively short distance, there are a free space propagation loss model, a model recommended by the International Telecommunications Union Radiocommunication Division (ITU-R), and the like. The propagation loss in free space, that is, the free space propagation loss L _f is expressed by Equation 8.

In other words, the free space propagation loss is proportional to the square of the distance and the -2 of the wavelength.

ここでdは伝搬距離[m]、R_bpはブレークポイントまでの距離[m]を示している。ブレークポイントまでの距離R_bpは、数式10にて求めることができる。

数式10は、数式6と同様である。 As an ITU-R recommendation model, there is an outdoor short-distance propagation model corresponding to each environment (ITU-R recommendation P.1411). ITU-R Recommendation P.1411 has a street canyon model in the UHF band as a model corresponding to the line-of-sight environment, which consists of two slopes and breakpoints. The lower limit value L _{LoS, l} of the propagation loss by the street canyon model of ITU-R recommendation P.1411 is given by Equation 9.

Here, d represents the propagation distance [m], and R _bp represents the distance [m] to the breakpoint. The distance R _bp to the breakpoint can be obtained by Equation 10.

Expression 10 is the same as Expression 6.

下限値L_LoS,lを与える数式9は、大地反射を考慮した2波モデルの近似式と考えられる。 Further, in Equation 9, the transmission loss L _{bp at} the break point is given by Equation 11.

Equation 9 that gives the lower limit L _{LoS, l} is considered to be an approximate equation of a two-wave model that takes into account ground reflection.

上限値L_LoS,uの数式12には20dBのフェージングがあり、ブレークポイントより近い距離においては、シャドウイングの影響のため、数式9と異なり距離減衰係数が25となっている。 Further, the upper limit value L _{LoS, u} of the propagation loss is given by the following equation.

Equation 12 of the upper limit L _{LoS, u} has a fading of 20 dB, and the distance attenuation coefficient is 25 at a distance closer to the breakpoint due to the influence of shadowing, unlike Equation 9.

(Experiment 1)
An experiment was conducted to compare the two-wave model used in the interference estimation system of the embodiment with a free space propagation loss model as a comparative example and a propagation model defined in ITU-R recommendation P.1411. As shown in Fig. 2, at the point a, transmission power is set to 0 dBm for a transmission antenna height of 1.5 m, 13.9 m, and 25.8 m using a transmission antenna with a gain of 1.6 dBi, and an antenna height of 1.2 m Received using a receiving antenna with a gain of 9.4 dBi in the directivity direction at point d. Similarly, at point b, the transmission power is 0 dBm at an antenna height of 27.2 m, and transmission is performed using a transmission antenna with a gain of 1.6 dBi. At a point d of antenna height 1.2 m, a receiving antenna with a directivity direction gain of 9.4 dBi is set. Received using. Note that point d is received while moving.

  In the experiment, the gain due to the directivity of the transmitting antenna and the receiving antenna was considered. That is, based on the positional relationship information of the transmitting and receiving antennas, the directivity gain in the line-of-sight direction of the used antenna was calculated to correct the received power. Furthermore, the propagation characteristics were calculated and evaluated in consideration of the loss of the cable used.

  The results of Experiment 1 are shown in FIGS. Fig. 3 shows the measurement results when the antenna height of the transmitting antenna at point a is 1.5 m, Fig. 4 shows the same antenna height of 13.9 m, and Fig. 5 shows the same antenna height of 25.8 m. Show. FIG. 6 shows the measurement results when the antenna height of the transmitting antenna is 27.2 m at point b. As shown in Figs. 3 to 6, the measured value of propagation loss exceeds the free space propagation loss model at a short distance from the breakpoint, but agrees with the propagation model of ITU-R P.1411 shown in Equation 9. I understand that From the breakpoint, it is smaller than the ITU-R P.1411 model, which is consistent with the two-wave model.

  Here, in the results shown in FIGS. 4 to 6, measurement data having a distance between transmission and reception of 400 m or more, which becomes an environment outside the line of sight due to the inclination of the course, is omitted. Since the model used for verification includes the term of antenna height, it is possible to cope with the case where the antenna height of the transmission / reception antenna is changed.

  FIG. 7 shows the measurement results when the antenna height of the transmitting antenna is 5.0 m at point b. As shown in FIG. 7, in the propagation between the points c and e, the lower limit value of the measured propagation loss is larger than the free space propagation loss at a short distance from the break point, and the ITU-RP.1411 model at the distance from the break point. It can be seen that it is smaller and consistent with the two-wave model.

(Experiment 2)
Similar to Experiment 1, an experiment was performed to compare the two-wave model used in the interference estimation system of the embodiment and the free space propagation loss model as a comparative example. As shown in FIG. 8, the antenna height is 20 m at the transmission point, the transmission power is 30 dBm, and transmission is performed using a transmission antenna having a gain of 7.7 dBi, and the reception antenna having a gain of 2.2 dBi at the reception point having an antenna height of 1.7 m. Received using.

  The result of Experiment 2 is shown in FIG. As shown in FIG. 9, in the line-of-sight environment, it is shown that the measured received power distribution increases by about 6 dB at the maximum from the estimated value based on the free space propagation loss model. Further, according to FIG. 9, since the presence of breakpoints is shown, it can be seen that the two-wave model based on ground reflection is followed. On the other hand, it is shown that the received power increases again at a point far from the break point.

  Based on the results shown in Fig. 9, we examined a model in which a loss curve according to the two-wave model and a curve with a loss 6 dB smaller than the free space loss were connected at a breakpoint. FIG. 10 shows a model combining the two-wave model and the free space loss model. FIG. 11 superimposes the combined model shown in FIG. 10 on the result of FIG. As shown in Fig. 11, it can be seen that the measured received power distribution deviates from a model combining the two-wave model and free space loss at a relatively long distance (about several hundred meters or more) (in the figure). (Shaded area). Also, the right side of the figure shows the received power distribution that seems to be due to the topography (mountainous area), which also deviates from the combined model.

  The difference between the measured value and the combination model shown in FIG. 11 is considered to be due to the large difference in elevation between the transmission point and the reception point. That is, as shown in FIG. 12, since the difference in elevation between the transmission point and the reception point is large, the difference in the path length between the direct wave and the reflected wave is not small even in the distance, and as a result, the break point is shifted to the far side. become. From this, as shown in Fig. 13, it can be seen that when the horizontal distance between the transmission point and the reception point exceeds approximately 1 km, the antenna height should be estimated at a height that takes into account the altitude, not the ground height. Dashed line).

(Propagation model used in the interference estimation system of the embodiment)
Based on the above experimental results, the propagation model used in the interference estimation system of the embodiment uses Equation 13 in which 6 dB is subtracted from the free space propagation loss in consideration of fading due to two waves at a short distance from the breakpoint. Is considered reasonable,

On the other hand, it is appropriate to use the attenuation curve expressed by Equation 5 beyond the breakpoint. At this time, the breakpoint can be obtained by Equation 14 from Equation 5 and Equation 13.

ここで、R_bppは送信点からブレークポイントの水平距離（数式14）、h_b1およびh_m1はそれぞれ送信アンテナ地上高および受信アンテナ地上高、h_b2およびh_m2はそれぞれ送信アンテナ標高および受信アンテナ標高である。なお、d>1kmとなる条件下においては、数式15の第1式、すなわちd≦R_bppであるものとして伝搬損失L_Iを算出してもよい。すなわち、与干渉エリア推定のための伝搬損失モデルを数式16により算出してもよい。

Furthermore, when the distance between the transmission and reception points exceeds approximately 1 km, it is desirable to use a height that includes the altitude as the antenna height. From the above, the propagation loss model for estimating the interference area of the secondary user based on the two-wave model can be summarized by Equation 15.

Where R _bpp is the horizontal distance from the transmission point to the breakpoint (Formula 14), h _b1 and h _m1 are the transmission antenna ground height and reception antenna ground height, and h _b2 and _{hm 2} are the transmission antenna elevation and reception antenna elevation, respectively. It is. Note that, under the condition where d> 1 km, the propagation loss L _I may be calculated assuming that the first equation of Equation 15, that is, d ≦ R _bpp is _satisfied . In other words, a propagation loss model for estimating the interference area may be calculated using Equation 16.

(Configuration of interference estimation system of embodiment)
Subsequently, the configuration of the interference estimation system of the embodiment will be described. As shown in FIG. 14, the interference estimation system 1 according to the embodiment includes an input unit 10, a terrain information acquisition unit 20, an interference area determination unit 30, a contour map generation unit 40, a storage unit 50, a terrain information database 60, and a display. Part 70 is provided.

  The input unit 10 is the position information of the transmission point of the target secondary usage system, altitude information, transmission frequency, transmission output, gain and directivity characteristics of the transmission antenna, antenna height of the transmission antenna, antenna height of the assumed reception antenna, It is an input interface that accepts various parameters such as reference information for determining interference. The input unit 10 is realized by, for example, a keyboard or a communication interface. The storage unit 50 is an auxiliary storage device such as a memory or a hard disk, and stores information received by the input unit 10.

The terrain information acquisition unit 20 is a calculation unit that acquires terrain information around the transmission point from the terrain information database 60 based on the position information of the transmission point stored in the storage unit 50. The interference area determination unit 30 calculates the propagation loss L _I using various parameters stored in the storage unit 50 and Equations 14 and 15 (or Equation 16), and the target secondary usage system becomes the primary usage system. The limit distance that gives interference is calculated. That is, the interference area determination unit 40 uses the propagation loss LI to give an interference area that the target secondary usage system gives to the primary usage system (if the primary usage system exists in that area, the interference is given) A region).

  The contour map generator 40 generates the contour map information on the map from the information on the interference area defined by the interference area determination unit 30. The terrain information database 60 is a database that stores terrain information of a region including a transmission point of a target secondary usage system. The terrain information database 60 can provide altitude information around the transmission point as shown in FIG. 15, for example, using the position information as a query. The elevation information around the transmission point includes, for example, elevation information for every 10 degrees from the transmission point and for each distance.

  The display unit 70 is an output interface that outputs interference area information generated by the contour map generation unit 40 such as an LED display. The display unit 70 is not limited to display as an image, and may output information itself.

(Operation of the interference estimation system of the embodiment)
Next, the operation of the interference estimation system 1 according to the embodiment will be described with reference to FIG. When the user inputs the parameters of the secondary usage system to the input unit 10, the input unit 10 stores the received information in the storage unit 50 (step 100, hereinafter referred to as “S100”).

  When various parameters are stored in the storage unit 50, the terrain information acquisition unit 20 radiates from the transmission point based on the position information of the transmission point stored in the storage unit 50 and the terrain information stored in the terrain information database 60. The altitude information for each predetermined angle is generated (S110). As shown in FIG. 15, in the altitude information generated by the topographic information acquisition unit 20, the azimuth at the transmission point, the distance from the transmission point, and the altitude are associated with each other. The terrain information acquisition unit 20 also provides altitude information at the position of the transmitting antenna and altitude information at the position of the receiving antenna according to the position information of the transmitting antenna and the position information of the receiving antenna.

The interference area determination unit 30 determines the transmission power stored in the storage unit 50, the gain of the transmission antenna at the azimuth angle, and the electric field strength allowed for the primary usage system for the reference azimuth angle (for example, 0 degrees). Based on this, the propagation loss L _I is calculated when the electric field strength is reached at the azimuth angle (when the maximum electric field strength is reached) (S120).

  Next, the interference area determination unit 30 uses the transmission antenna height and the reception antenna height stored in the storage unit 50, and further uses the transmission antenna height and the reception antenna height and Equations 14 and 15 or Equation 16, and The distance d is calculated (S130). The interference area determination unit 30 can acquire the elevation information of the transmission point from the terrain information acquisition unit 20 using the position information of the transmission point stored in the storage unit 50 as a query. The altitude information at the position of the receiving antenna can be acquired by giving the position information, the azimuth angle and the distance d to the transmission point to the terrain information acquisition unit 20. The altitude information at the position of the antenna is obtained while inquiring the terrain information acquisition unit 20.

The interference area determination unit 30 adds a predetermined angle (for example, 10 degrees) to the azimuth angle (S150) when the calculation has not been completed for all azimuths (No in S140), and propagates at the new azimuth angle. Calculate the loss L _I. Thereafter, similarly, the interference area determination unit 30 calculates the distance d at the azimuth angle (S130).

When the interfering area determination unit 30 has finished the calculation for all the azimuths (Yes in S140), the contour map generation unit 40 calculates the distance d information for all the azimuths calculated by the interfering area determination unit 30 and the terrain Using the terrain information stored in the information database 60, the contour map information indicating the boundary line at which the secondary usage system can interfere with the primary usage system is generated (S160).
When the contour diagram information is generated, the display unit 70 presents the contour diagram information to the user.

  Thus, according to the interference estimation system of this embodiment, since the propagation loss model according to Equations 14 and 15 or Equation 16 is used, the secondary usage system whose frequency overlaps or is close to that of the primary usage system is the primary usage system. The area information that does not interfere with the image can be obtained. By ensuring that such area information and service area information of the primary usage system do not overlap, it is possible to easily demarcate where the secondary usage system can be operated.

  Further, since the interference estimation system of this embodiment uses position information and a propagation loss model according to Equations 14 and 15 or Equation 16, even when a secondary usage system that does not interfere with the primary usage system moves. As long as the position information of the transmission point is prepared, it can be easily determined whether or not the primary use system is interfered. Therefore, a secondary use system that moves can be realized by using it together with a positioning unit such as GPS. Moreover, since the interference estimation system of this embodiment can speed up the estimation calculation, the secondary usage system can be realized as a mobile system.

(Configuration of Wireless Device of Embodiment)
Here, with reference to FIG. 17, a secondary usage system using the interference estimation system of the embodiment will be described. As shown in FIG. 17, the wireless device 2 of this embodiment includes an input unit 10, a position information acquisition unit 15, a terrain information acquisition unit 20, a white space information acquisition unit 25, and an interference area determination unit 30. A contour map generator 40, a storage unit 50, a white space database (WSDB) 55, a terrain information database 60, and a radio unit 80. Since radio apparatus 2 shown in FIG. 17 incorporates the interference estimation system shown in FIG. 14, common elements are denoted by common reference numerals, and redundant description is omitted.

  The position information acquisition unit 15 is a calculation unit that acquires or generates position information indicating the position of the wireless device 2. The position information acquisition unit 15 acquires its own position as a parameter including latitude, longitude, altitude, and the like, for example, like GPS (Global Positioning System). The location information acquisition unit 15 is not limited to the one that calculates the location information using a satellite such as GPS, and generates location information by receiving radio waves from a radio base station installed on the ground. There may be.

  The white space database 55 is a database in which white space information related to white space such as position information, frequency information, transmission power information, transmission antenna gain information, and a cover area using those parameters is registered in advance. is there. The white space information acquisition unit 25 is a calculation unit that acquires the white space information from the white space database 55. When the position information is given, the white space database 55 outputs various parameters of the adjacent primary use system based on the position information. The white space database 55 is not limited to the one built in the wireless device 2, and may be connected via a network. In this case, the white space information acquisition unit 25 acquires white space information from the outside via the network.

  The radio unit 80 is a group of transmission / reception circuits that can transmit and receive in the frequency band of the secondary usage system. The radio unit 80 has a function of controlling transmission power in accordance with given transmission power information.

(Operation of Wireless Device of Embodiment)
Subsequently, with reference to FIG. 18, an operation of the wireless device 2 according to the embodiment will be described. When the user inputs the parameters of the secondary usage system to the input unit 10, the input unit 10 stores the received information in the storage unit 50. Further, the position information acquisition unit 15 acquires the position information of the wireless device 2 (S200). The position information acquisition unit 15 passes the acquired position information to the terrain information acquisition unit 20.

  The terrain information acquisition unit 20 generates altitude information for each predetermined angle radially from the transmission point based on the position information received from the position information acquisition unit 15 and the terrain information stored in the terrain information database 60 (S210). ). Further, the white space information acquisition unit 25 acquires, from the white space database 55, cover area information indicating the communication range of the adjacent primary use system based on the position information acquired by the position information acquisition unit 15. The cover area information of the primary usage system is information indicating an area in which transmission / reception of the primary usage system is guaranteed. If the primary usage system is a broadcast system, for example, an area where the received electric field intensity is 51 dBμV / m or more is a broadcast range (communication range: cover area).

The interference area determination unit 30 transmits the transmission power allowed for the wireless device 2 stored in the storage unit 50 for the reference azimuth angle (for example, 0 degrees), the gain of the transmission antenna of the wireless device 2 at the azimuth angle, based on the field intensity allowed for primary usage system, calculates the propagation loss L _I when (if the maximum electric field intensity) to be the electric field intensity in the azimuth (S220).

  Next, the interference area determination unit 30 transmits the transmission antenna height and the altitude of the wireless device 2 stored in the storage unit 50, the reception antenna height (for example, 10 m) of the primary usage system acquired by the white space information acquisition unit 25, and The distance d between the transmission and reception points is calculated using the altitude and the equations 14 and 15 or the equation 16 (S230). Since the altitude information at the position of the receiving antenna can be acquired by giving the position information, azimuth angle, and distance d of the radio device 2 to the terrain information acquisition unit 20, the interference area determination unit 30 calculates the distance d. The altitude information at the position of the receiving antenna is obtained while making an inquiry to the terrain information acquisition unit 20.

If the calculation is not completed for all azimuths by the interference area determination unit 30 (No in S240), a predetermined angle (for example, 10 degrees) is added to the azimuth (S250), and the propagation loss at the new azimuth Calculate L _I. Thereafter, similarly, the interference area determination unit 30 calculates the distance d at the azimuth angle (S230).

When the calculation is completed for all the azimuth area determination units 30 (Yes in S240), the contour map generation unit 40 includes information on the distance d for all the azimuths calculated by the interference area determination unit 30; Using the terrain information stored in the terrain information database 60, the secondary usage system generates contour map information indicating a boundary line that can interfere with the primary usage system (S260).
When the contour map information is generated, the contour map generation unit 40 passes the contour map information to the interference area determination unit 30.

  The interference area determination unit 30 uses the coverage area information of the adjacent primary use system acquired by the white space information 25 and the contour map information received from the contour map generation unit 40 to overlap each other as viewed from the wireless device 2. A search is made for an azimuth angle at which becomes the largest (S270). There may be a plurality of azimuth angles.

The interference area determination unit 30 calculates a distance d that does not overlap each other based on the cover area of the primary usage system and the contour diagram information of the wireless device 2 for the azimuth obtained as a result of the search, and the distance d Is used to calculate the propagation loss L _I. The interference area determination unit 30 calculates the allowable transmission power using the obtained propagation loss L _I (S280). The interference area determination unit 30 passes the obtained allowable transmission power to the radio unit 80 as transmission power information.

  The radio unit 80 sets transmission power based on the received transmission power information (S290).

  According to the wireless device of this embodiment, the allowable transmission power that does not interfere with the adjacent primary usage system can be obtained dynamically, so that a mobile system using the secondary usage system can be realized.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 10 ... Input part, 20 ... Topographic information acquisition part, 30 ... Interference area determination part, 40 ... Contour map production | generation part, 50 ... Memory | storage part, 60 ... Topographic information database, 70 ... Display part.

Claims (4)

Presence or absence of interference that the second radio system that uses or overlaps with the first radio system and that has a lower priority than the first radio system uses the frequency band gives the first radio system An interference estimation system for estimating
Position information of transmission point of the second wireless system, transmission frequency information, transmission output information, gain information and ground height information of the transmission antenna, gain information and ground height information of the reception antenna of the second wireless system, and A storage unit that stores permissible electric field strength information of radio waves transmitted from the second radio system that are allowed from the first radio system;
Based on the transmission output information, the gain information of the transmission antenna and the allowable electric field strength information, a loss calculation unit that calculates the minimum propagation loss allowed for the second radio system;
Using the propagation loss calculated by the loss calculation unit, the transmission frequency information, the ground height information of the transmitting antenna and the ground height information of the receiving antenna,

(Where L _I is the propagation loss, h _b1 is ground clearance, h _m1 is ground height of the receiving antenna of the transmitting antenna) distance acquisition of calculating the distance d between the transmitting antenna and the receiving antenna based on the arithmetic expression And
A map generation unit that generates region information of a region where the second wireless system does not affect the first wireless system based on the position information of the transmission point and the distance d calculated by the distance acquisition unit. An interference estimation system characterized by that. A terrain information acquisition unit that acquires the elevation information of the transmission point and the elevation information at the position of the receiving antenna,
The distance acquisition unit further uses the altitude information acquired by the terrain information acquisition unit,

(Where L _I is the propagation loss, h _b1 is the ground height of the transmitting antenna, h _m1 is the ground height of the receiving antenna, h _b2 is the altitude of the transmitting antenna, and h _m2 is the altitude of the receiving antenna) 2. The interference estimation system according to claim 1, wherein a distance d between the transmitting antenna and the receiving antenna is calculated based on   3. The interference estimation system according to claim 1, wherein the distance acquisition unit calculates the distance d for each predetermined azimuth angle radially from the transmission point. A wireless device according to a second wireless system having a lower priority than the first wireless system using a frequency band that overlaps or is close to the first wireless system,
A location information acquisition unit that acquires location information of the self including the altitude;
A storage unit for storing transmission frequency information, transmission output information, transmission antenna gain information and antenna height information of the second wireless system;
Receiving antenna gain information and ground height information and altitude information of the first radio system, service area information indicating the position and range of the service area, and the second radio system allowed from the first radio system A white space information acquisition unit for acquiring allowable field strength information of radio waves transmitted by
Based on the transmission output information, the gain information of the transmission antenna and the allowable electric field strength information, a loss calculation unit that calculates the minimum propagation loss allowed for the second radio system;
Using the propagation loss calculated by the loss calculation unit, the transmission frequency information, the ground height information of the transmitting antenna and the ground height information of the receiving antenna,

(Where L _I is the propagation loss, h _b1 is the ground height of the transmitting antenna, h _m1 is the ground height of the receiving antenna, h _b2 is the altitude of the transmitting antenna, and h _m2 is the altitude of the receiving antenna) A distance acquisition unit that calculates a distance d to the receiving antenna based on
A map generation unit that generates region information of a region where the second wireless system does not affect the first wireless system based on the position information of the transmission point and the distance d calculated by the distance acquisition unit;
Based on the service area information of the first radio system and the area information, an interference determination unit that calculates a boundary point that most interferes with the first radio system;
A wireless device comprising: a power calculation unit that calculates a transmission output that does not interfere with the first wireless system based on the boundary point and the propagation loss.

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