JP7380899B2 - Wireless communication system, field strength control method, software radio, and program for field strength control - Google Patents

Description

This disclosure relates to a wireless communication system, a field strength control method, a software radio, and a program for controlling field strength, and particularly to a wireless communication system suitable for controlling field strength to satisfy regulations for weak radio stations. , relates to a field strength control method, a software defined radio, and a program for field strength control.

Patent Document 1 discloses a wireless communication device that can suppress wasteful power consumption of a communication partner. This device detects the field strength of radio waves received from a communication partner and determines whether the value is within a preset reference range. Additionally, this device instructs the communication partner to change the transmission output so that the field strength of the radio waves received from the communication partner falls within the reference range. As a result, the device described in Patent Document 1 realizes a system that can control the field strength of radio waves used for communication.

Japanese Patent Publication No. 2007-259055

In Japan, when using a wireless device as a weak radio station that does not require notification as a wireless station, the electric field strength at a distance of 3 meters from the wireless device must be kept below the allowable value specified by the Ministry of Internal Affairs and Communications regulations. There is.

The device described in Patent Document 1 instructs to change the transmission output according to the received field strength of radio waves from the communication partner. In other words, this device instructs the communication partner to increase or decrease its transmission output in a state where the transmission power value, antenna gain, and distance from the communication partner are unknown.

In this case, the transmission power value of the communication partner itself is not subject to control, and naturally, the electric field strength at a position 3 m away from the communication partner is also not subject to control. For this reason, when the technology described in Patent Document 1 is applied to a weak radio station, it is difficult to reliably keep the field strength of the radio waves sent from the communication partner below the permissible value of the field strength allowed for the weak radio station. Can not.

The present disclosure utilizes software-defined radio technology to control transmission power so that the field strength of radio waves transmitted from a communication partner is below the regulations allowed for wireless stations, thereby meeting regulations imposed on wireless stations. The first objective is to provide a wireless communication system that can satisfy the following.

Additionally, the present disclosure utilizes software defined radio technology to control transmission power so that the field strength of radio waves transmitted from a communication partner is below the regulations allowed by the wireless station, thereby reducing the burden imposed on the wireless station. A second object of the present invention is to provide a transmission power control method that can satisfy the above regulations.

Additionally, the present disclosure utilizes software defined radio technology to control transmission power so that the field strength of radio waves transmitted from a communication partner is below the regulations allowed by the wireless station, thereby reducing the burden imposed on the wireless station. The third objective is to provide a software defined radio that can satisfy the above regulations.

Additionally, the present disclosure utilizes software defined radio technology to control transmission power so that the field strength of radio waves transmitted from a communication partner is below the regulations allowed by the wireless station, thereby reducing the burden imposed on the wireless station. A fourth purpose is to provide a transmission power control program that can satisfy the above regulations.

In order to achieve the above object, a first aspect includes a hardware resource for wireless communication that can be reconfigured by changing software, and a memory that stores software for making the hardware resource compatible with wireless communication. , a wireless communication system utilizing a software defined radio, comprising: a control unit that reconfigures the hardware resources using software stored in the memory; and an antenna that transmits and receives radio signals; The first memory area stores antenna gain information that is the relationship between the gain of the antenna and the frequency, and the tolerance information that is the relationship between the allowable value of electric field strength specified for the wireless station and the frequency. a second memory area, the control unit performs a selection process of selecting a communication method and a frequency band to be used for communication, a process of configuring a communication line using the communication method and the frequency band, and a process that the wireless station satisfies. a process of calculating a specified distance propagation loss L occurring in the frequency band at a position separated from the antenna by a distance specified as a position at which the electric field strength to be compared with a power tolerance value R is to be measured; and the first memory. gain read processing for reading out the gain G exhibited by the antenna in the frequency band from the region; processing for reading out the allowable value R in the frequency band from the second memory region; and transmission power reading according to P = R - G + L. It is desirable to perform the process of calculating the upper limit value of P.

Further, a second aspect includes a hardware resource for wireless communication that can be reconfigured by changing software, a memory that stores software for making the hardware resource compatible with wireless communication, and a memory that stores software for making the hardware resource compatible with wireless communication. A field strength control method utilizing a software defined radio comprising a control unit that reconfigures the hardware resources using software, and an antenna that transmits and receives radio signals, the method comprising: a relationship between the gain of the antenna and the frequency; storing antenna gain information in a first memory area; storing tolerance information in a second memory area, which is a relationship between a frequency and an electric field strength tolerance defined for a wireless station; A step of selecting a communication method and a frequency band to be used for communication, a step of configuring a communication line using the communication method and the frequency band, and a position at which to measure the electric field strength to be compared with a tolerance value R that the wireless station should satisfy. calculating a specified distance propagation loss L occurring in the frequency band at a position separated from the antenna by a specified distance; and reading out a gain G exhibited by the antenna in the frequency band from the first memory area. The method preferably includes the steps of: reading an allowable value R in the frequency band from the second memory area; and calculating an upper limit value of the transmission power P according to P = R - G + L.

Further, a third aspect includes a hardware resource for wireless communication that can be reconfigured by changing software, a memory that stores software for making the hardware resource compatible with wireless communication, and a memory that stores software for making the hardware resource compatible with wireless communication. A software defined radio device comprising: a control unit that reconfigures the hardware resources using software; and an antenna that transmits and receives radio signals; and a second memory area that stores permissible value information that is a relationship between a permissible value of electric field strength defined for a wireless station and a frequency, and the control unit is configured to control the communication A selection process for selecting a method and a frequency band, a process for configuring a communication line using the communication method and the frequency band, and a position defined as a position at which to measure the electric field strength to be compared with a tolerance value R that the wireless station should satisfy. a process of calculating a specified distance propagation loss L that occurs in the frequency band at a position separated from the antenna by a distance corresponding to the antenna; and a gain read process of reading out the gain G that the antenna exhibits in the frequency band from the first memory area. It is desirable to execute the following steps: read out the allowable value R in the frequency band from the second memory area; and calculate the upper limit value of the transmission power P according to P = R - G + L.

Further, the fourth aspect is a transmission power control program, and preferably includes a program for causing a computer to realize the functions of the software defined radio according to the third aspect.

According to the first to fourth aspects, it is possible to provide users with good communication by utilizing software defined radio technology and utilizing various communication methods and frequency bands. Then, the transmission power P can be set for each frequency band used so that the electric field strength is equal to or less than the tolerance value R imposed on the wireless station. Therefore, according to these aspects, high quality communication can be provided to the user while satisfying the regulations of the wireless station.

This shows the permissible value of electric field strength stipulated by the Ministry of Internal Affairs and Communications of Japan for weak radio stations. 1 is a diagram showing a configuration of a software defined radio according to Embodiment 1 of the present disclosure; FIG. 3 is a block diagram for explaining elements configured inside the software defined radio shown in FIG. 2. FIG. 4 is a flowchart for explaining the content of processing executed by the software defined radio shown in FIG. 3. FIG. FIG. 3 is a diagram showing the configuration of a software defined radio according to a second embodiment of the present disclosure. 6 is a block diagram for explaining elements configured inside the software defined radio shown in FIG. 5. FIG. 7 is a flowchart for explaining the content of processing executed by the software defined radio shown in FIG. 6. FIG.

Embodiment 1.
[Weak radio station]
FIG. 1 shows the permissible values of electric field strength stipulated by the Ministry of Internal Affairs and Communications of Japan for weak radio stations. Specifically, FIG. 1 stipulates that the allowable value of electric field strength that a weak radio station must satisfy is as follows.
Frequency band below 322MHz: 500μV/m
Frequency band from 322MHz to 10GHz: 35μV/m
Frequency band from 10GHz to 150GHz: 35-500μV/m
Frequency band above 150GHz: 500μV/m

In Japan, a wireless device whose electric field strength at a distance of 3 meters is less than the above-mentioned allowable value is permitted to be used as a weak radio station that does not require a license. This embodiment discloses a wireless device that can establish communications using various frequency bands and that can reliably satisfy the requirements regarding the permissible value of weak radio stations in the plurality of frequency bands.

[Configuration of Embodiment 1]
FIG. 2 shows the configuration of software defined radio 10 used in the wireless communication system according to Embodiment 1 of the present disclosure. As shown in FIG. 2, the software defined radio 10 is connected to an antenna 12 and can perform wireless communication with other wireless devices via the antenna 12.

The antenna 12 supports a wide range of frequencies and can send and receive wireless signals in various frequency bands. Antenna gain G generally changes depending on the frequency used for wireless communication. The antenna 12 used in this embodiment also has a characteristic that the gain changes depending on the frequency used.

The software defined radio 10 includes hardware that can be reconfigured using software. In this embodiment, the communication method (WiFi (registered trademark) method, LTE method, etc.) and frequency band used for wireless communication can be changed by changing the software as necessary.

As shown in FIG. 2, the software defined radio 10 includes an FPGA (Field Programmable Gate Array) 14. The FPGA 14 is a device that can program various logic circuit configurations by rewriting software. In the software defined radio 10, the FPGA 14 functions as a baseband processing unit that processes baseband signals transmitted through communication. The FPGA 14 may be replaced with a general computer or DSP (Digital Signal Processor).

The software defined radio 10 includes an AD/DA converter 16 and an RF front end section 18. The AD/DA converter 16 and the RF front end section 18 process high frequency signals between the antenna 12 and the FPGA 12.

The software defined radio 10 further includes a control section 20. The control unit 20 includes various interfaces and a built-in CPU, memory, and the like. The control unit 20 controls the FPGA 14, the AD/DA converter 16, and the RF front end unit 18 by proceeding with processing according to a program stored in the memory. Specifically, the control unit 20 detects a request to the software defined radio 10 and reconfigures the hardware in response to the request.

The software defined radio 10 can change the communication method by changing the software and reconfiguring the hardware resources. In the example shown in FIG. 2, the software defined radio 10 is configured with hardware corresponding to three communication methods A to C.

The software defined radio 10 can also change the frequency band used for communication and the width of the frequency band. In the example shown in FIG. 2, three rectangular frames 22, 24, and 26 labeled "communication method A" to "communication method C" are shown within the frame of the software defined radio 10. These rectangular frames 22, 24, and 26 represent the frequency bands of communication lines configured within the software defined radio 10.

Specifically, the positions of the rectangular frames 22, 24, and 26 in the vertical direction in the drawing represent the height of the "frequency band." Further, the vertical widths of the rectangular frames 22, 24, and 26 represent the "width" of each frequency band. That is, the three rectangular frames 22, 24, and 26 shown in FIG. 2 illustrate the following three events.

1. Three communication lines corresponding to each of the rectangular frames 22, 24, and 26 are prepared within the software defined radio 10 by reconfiguring the hardware resources. Hereinafter, for convenience, they will be referred to as "communication lines 22, 24, and 26."
2. The communication lines 22, 24, and 26 use different frequency bands, and the frequency bands become lower in the order of the communication lines 22, 24, and 26.
3. The frequency bandwidths of communication lines 22, 24, and 26 must all be the same.

The software defined radio 10 transmits data and audio signals supplied by wire from external devices etc. via communication lines 22 , 24 , 26 , and also transmits wireless signals received by the antenna 12 to the communication lines 22 , 24 . , 26, it can be converted into data or audio signals.

The software defined radio 10 stores antenna gain information 28 in its built-in memory. The antenna gain information 28 includes the relationship between the gain G and the frequency for each of the plurality of antennas that are assumed to be used.

The software defined radio 10 also stores tolerance information 30 in its built-in memory. The tolerance information 30 includes the tolerance information shown in FIG. 1, that is, the relationship between the frequency and the tolerance value of the electric field strength at a distance of 3 m from the wireless device.

[Features of Embodiment 1]
In order to use the software defined radio 10 as a weak radio station, it is necessary to suppress the electric field strength at a position 3 m away from the antenna 12 to below the allowable value shown in FIG. As described above, the gain of the antenna 12 changes depending on the frequency used for communication. Further, the electric field strength at a distance of 3 m changes depending on the gain of the antenna 12. Therefore, in order to obtain the maximum output permissible as a weak radio station in various frequency bands, it is necessary to appropriately change the transmission output according to the frequency used for communication.

In order to meet the above requirements, the software defined radio 10 of this embodiment satisfies conditions 1 to 12 described below.
1. The software defined radio 10 includes an input interface for allowing a user to input information.
2. The user can specify a combination of communication method and frequency band via the input interface. When this designation is made, the software defined radio 10 configures a communication line corresponding to the designated communication method and frequency band.
3. The user can specify transmission capacity and transmission quality via the input interface. When this designation is made, the software defined radio 10 searches for a communication method and frequency band that embody the designated transmission capacity and transmission quality, and configures a communication line corresponding to the search results.

4. Information on the gain G regarding the antenna 12 attached to the software defined radio 10 is extracted from the antenna gain information 28, and further, with reference to that information, the gain G exhibited by the antenna 12 for the frequency used for communication is calculated. read out.
5. The propagation loss L that occurs at a position 3 m away from the antenna 12 at the frequency used for communication is calculated according to a known formula for free space propagation loss.
6. From the tolerance information 30, the tolerance value R of the electric field strength at the frequency used for communication is read.

7. Transmission power P to satisfy the conditions of a weak radio station is calculated based on the following relational expression. Note that the formula used to explain the present disclosure is a calculation formula expressed in dB.
P = R - G + L ... (1)
The electric field strength R3 at a position 3 m away from the antenna 12 is the value obtained by subtracting the propagation loss L at the 3 m position from the value obtained by adding the gain G to the transmission power P, and therefore can be expressed by the following equation.
R3 = P + G - L...(2)
In order to meet the requirements for a weak radio station, R3 must be kept below R. Then, by replacing R3 with R and rearranging the above equation (2) with respect to P, the above equation (1) is obtained. Therefore, according to the above equation (1), it is possible to calculate the maximum transmission power P that satisfies the conditions for a weak radio station.

8. Once the transmission power P that satisfies the conditions for a weak radio station is calculated, communication is performed using the communication method and frequency band that are the premise of the calculation.

[Specific configuration of Embodiment 1]
FIG. 3 is a block diagram for explaining elements configured inside the software defined radio 10 shown in FIG. 2 to realize the above functions.
As shown in FIG. 3, the software defined radio 10 includes a radio wave transmitter 32. The radio wave transmitter 32 modulates data and the like provided via wire from an external device into a transmission signal, and supplies the signal with transmission power P to the antenna 12.

A command for the transmission power P is given to the radio wave transmitter 32 from the transmission power calculator 34. The transmission power calculation unit 34 calculates the transmission power P by the following process.
1. The gain G of the antenna 12 at the frequency used for communication is read from the antenna gain information 28.
2. From the tolerance information 30, the tolerance value R of the electric field strength at the frequency used for communication is read.
The 3.3m propagation loss calculation unit 36 reads out the propagation loss (hereinafter referred to as "3m propagation loss L") that occurs at a position 3m away from the antenna 12 at the frequency used for communication.
4. Transmission power P is calculated by substituting allowable value R, gain G, and 3m propagation loss L into the above equation (1).

The 3m propagation loss calculation unit 36 calculates the 3m propagation loss L occurring at the frequency used for communication according to the free space propagation loss formula.

The frequency used for communication is selected by the line information selection section 38. The line information selection unit 38 selects the conditions of the communication line used for wireless communication, specifically, the combination of the communication method and frequency band used in the communication line. Line information 40 is input to the line information selection section 38 by the user. The user can directly input a combination of communication method and frequency band as the line information 40. In this case, the line information selection unit 38 selects the input communication method and frequency band to be used for communication.

The user can also input transmission capacity and transmission quality as the line information 40 instead of the communication method and frequency band. In this case, the line information selection unit 38 searches for a combination of a communication method and frequency band that satisfies the input transmission capacity and transmission quality, and selects the communication method and frequency band obtained as a result of the search to be used for communication. select. As a result, a communication line is set up to meet the user's request for communication.

FIG. 4 is a flowchart of processing executed in the control unit 20 of the software defined radio 10 to realize each function shown in FIG. In the routine shown in FIG. 3, first, a communication method and a frequency band used for communication are selected according to the line information 40 input by the user (step 100).

Next, the gain G of the antenna 12 at the selected frequency is read from the antenna gain information 28 (step 102).

Next, a 3m propagation loss L that occurs in a radio signal having the selected frequency at a position 3m away from the antenna 12 is calculated (step 104).

Further, from the tolerance information 30, a tolerance value R of electric field strength permitted for the frequency used for communication is read out (step 106).

When the above processing is completed, the transmission power P (=RG+L) is calculated according to the above equation (1) (step 108). As a result, the transmission power P that makes the electric field strength at the 3 m position match the allowable value R, that is, the maximum transmission power P that satisfies the requirements of the weak radio station, is calculated.

Once the transmission power P is calculated, communication using the transmission power P is started on the communication line using the communication method and frequency band selected in step 100 (step 110).

As described above, in the wireless communication system of this embodiment, the software defined radio 10 can appropriately configure a communication line that meets the user's request by rewriting the software. Then, the software defined radio 10 calculates the maximum transmission power P that satisfies the conditions for a weak radio station in the frequency band of the communication line, and starts communication with the transmission power P. Therefore, according to the system of the present embodiment, it is possible to efficiently operate the software defined radio 10 as a weak radio station while appropriately providing communication of good quality desired by the user.

Embodiment 2.
Next, a second embodiment of the present disclosure will be described with reference to FIGS. 5 to 7.
FIG. 5 is a diagram for explaining the configuration of the software defined radio 50 used in the wireless communication system of this embodiment. Note that in FIG. 5, the same elements as those shown in FIG. 2 are given the same reference numerals, and the description thereof will be omitted or simplified.

The software defined radio 50 of this embodiment includes an antenna module 52. Like the antenna 12 of the first embodiment, the antenna module 52 is compatible with a wide band of frequencies and has a characteristic that shows a gain G depending on the frequency. The antenna module 52 has a built-in memory. This memory stores the relationship between the gain G of the antenna module 52 and the frequency as antenna gain information 54.

The software defined radio 50 is realized by the same hardware configuration as the software defined radio 10 of the first embodiment. In this embodiment, the antenna gain information 54 described above is transferred to the memory built into the software defined radio 50. Hereinafter, the information stored in the software defined radio 50 through this transfer will be referred to as "antenna gain information 56." By referring to the antenna gain information 56, the software defined radio 50 can detect the gain G indicated by the antenna module 52 at the frequency used for communication.

[Features of Embodiment 2]
FIG. 6 is a block diagram for explaining the main elements configured inside the software defined radio 50 shown in FIG. 5. As shown in FIG. The configuration shown in FIG. 6 is similar to the configuration shown in FIG. 3 except for the following three points.
1. The antenna 12 is changed to an antenna module 52,
2. 3. Antenna gain information 54 stored in antenna module 52 is shown near antenna module 52; and 3. Antenna gain information 28 is replaced with antenna gain information 56.
Note that the same elements in FIG. 6 as those shown in FIG. 3 are given the same reference numerals, and the explanation thereof will be omitted or simplified.

As described above, the antenna gain information 56 is the antenna gain information 54 stored in the antenna module 52 that has been transferred. In the present embodiment, the transmission power calculation unit 34 reads out the allowable value R of electric field strength from the allowable value information 30, reads out the 3m propagation loss L from the 3m propagation loss calculation unit 36, and calculates the gain G indicated by the antenna module 52 from the antenna. Read out from the gain information 56. Then, by substituting them into the above equation (1), the maximum transmission power P (=RG+L) allowed for the weak radio station is calculated.

FIG. 7 is a flowchart of processing executed by the control unit 20 of the software defined radio 50 to realize the above functions. The flowchart shown in FIG. 7 is similar to the flowchart shown in FIG. 4 except that step 102 is replaced with step 112. Hereinafter, among the steps shown in FIG. 7, steps similar to those shown in FIG. 4 will be given the same reference numerals and the description thereof will be omitted or simplified.

In the routine shown in FIG. 7, following the processing in step 100, the gain G of the antenna module 52 at the selected frequency is read from the antenna gain information 56 (step 112).

Thereafter, in steps 104 and 106, the 3m propagation loss L and tolerance value R at the frequency to be used are respectively read out, and in step 108, the transmission power P (=RG+L) is calculated.

As explained above, the software defined radio 50 of this embodiment can calculate the maximum transmission power P allowed for a weak radio station, similarly to the software defined radio 10 of the first embodiment. Therefore, according to the wireless communication system of this embodiment, as in the case of Embodiment 1, the software defined radio 50 can be operated efficiently as a weak radio station while appropriately providing good quality communication desired by the user. can be provided to

[Modification of Embodiment 1 or 2]
By the way, in the first and second embodiments described above, the electric field strength at a position 3 m away from the wireless device is suppressed to below the allowable value R, based on the Japanese regulations for weak wireless stations. However, if the regulations for weak radio stations are different, the same process as in the first embodiment may be performed by using the 3 m as another distance according to the regulations.

Further, in the first and second embodiments described above, the target to which the calculation of the transmission power P is applied is limited to weak radio stations, but the present disclosure is not limited to this. The technology according to the present disclosure can be widely applied not only to weak radio stations but also to radio stations for which a permissible value for electric field strength is set.

Furthermore, in Embodiments 1 and 2 described above, the user is given the option to input the combination of communication method and frequency band, and the option to input the transmission capacity and transmission quality. The options are not limited to these. For example, only one of the communication method and frequency band may be input, and the other may be determined so that the standard transmission capacity and transmission quality are satisfied. Furthermore, it is also possible to obtain input for only one of the transmission capacity and transmission quality, and apply a reference value to the other to search for a communication system and frequency band.

Furthermore, in the first and second embodiments described above, the software defined radios 10 and 50 start communication after calculating the transmission power P. When the software defined radios 10 and 50 are used as weak radio stations, this function may be changed to a function that prohibits the start of communication until the transmission power P is determined.

Further, in the first and second embodiments described above, the software defined radios 10 and 50 start communication with the transmission power P calculated in step 108, but the present disclosure is not limited to this. For example, the transmission power P may be positioned as the upper limit of the transmission power used for communication, and the software defined radios 10 and 50 may use smaller transmission power as long as the desired transmission quality can be obtained.

Furthermore, in the second embodiment described above, the antenna gain information 54 stored in the memory of the antenna module 52 is transferred to the memory of the software defined radio 50, and the antenna gain information 56 stored in the software defined radio 50 is transmitted. It is used to calculate the electric power P. However, the present disclosure is not limited thereto, and the antenna gain information 54 stored in the antenna module 52 may be used to directly calculate the transmission power P.

10, 50 Software defined radio 12 Antenna 28, 54, 56 Antenna gain information 30 Tolerance information 34 Transmission power calculation section 36 3m propagation loss calculation section 52 Antenna module
L Propagation loss at a distance of 3m
R electric field strength tolerance
P transmit power
G gain

Claims (8)

a hardware resource for wireless communication that can be reconfigured by changing software; a memory that stores software for making the hardware resource compatible with wireless communication; A wireless communication system that utilizes a software defined radio that includes a control unit that reconfigures hardware resources and an antenna that transmits and receives wireless signals,
The software defined radio includes:
a first memory area that stores antenna gain information that is a relationship between the gain and frequency of the antenna;
and a second memory area storing tolerance information that is a relationship between the tolerance value of electric field strength specified for the wireless station and the frequency,
The control unit includes:
a selection process for selecting a communication method and frequency band to be used for communication;
processing for configuring a communication line using the communication method and the frequency band;
A process of calculating a specified distance propagation loss L occurring in the frequency band at a position separated from the antenna by a distance specified as a position at which the electric field strength to be compared with a tolerance value R that the wireless station should satisfy;
a gain reading process of reading out a gain G exhibited by the antenna in the frequency band from the first memory area;
a process of reading a tolerance value R in the frequency band from the second memory area;
A process of calculating an upper limit value of transmission power P according to P = R - G + L,
A wireless communication system that performs. The first memory area is provided in a memory built into the software defined radio,
The first memory area stores antenna gain information including a relationship between gain and frequency for each of a plurality of antennas that are assumed to be used,
2. The wireless communication system according to claim 1, wherein the gain reading process includes a process of reading a gain G that an antenna attached to the software defined radio indicates in the frequency band from the first memory area. The antenna is provided as part of an antenna module,
The wireless communication system according to claim 1, wherein the antenna module includes a memory including the first memory area. The software defined radio includes an input interface that accepts input from a user,
The selection process is
a process of accepting designation of a communication method and frequency band via the input interface;
a process of selecting a specified communication method and frequency band to be used for communication;
The wireless communication system according to any one of claims 1 to 3, comprising: The software defined radio includes an input interface that accepts input from a user,
The selection process is
a process of accepting specifications of transmission capacity and transmission quality via the input interface;
A process of searching for a communication method and frequency band that satisfy specified transmission capacity and transmission quality;
a process of selecting the communication method and frequency band obtained as a result of the search as those to be used for communication;
The wireless communication system according to any one of claims 1 to 4, comprising: a hardware resource for wireless communication that can be reconfigured by changing software; a memory that stores software for making the hardware resource compatible with wireless communication; A field strength control method utilizing a software defined radio equipped with a control unit that reconfigures wear resources and an antenna that transmits and receives wireless signals, the method comprising:
storing antenna gain information, which is the relationship between the antenna gain and frequency, in a first memory area;
storing tolerance information, which is a relationship between a frequency and an electric field strength tolerance defined for the wireless station, in a second memory area;
a step of selecting a communication method and frequency band to be used for communication;
configuring a communication line using the communication method and the frequency band;
Calculating a specified distance propagation loss L occurring in the frequency band at a position separated from the antenna by a distance specified as a position at which the electric field strength to be compared with a tolerance value R that the wireless station should satisfy;
reading a gain G exhibited by the antenna in the frequency band from the first memory area;
reading a tolerance value R in the frequency band from the second memory area;
calculating an upper limit value of transmission power P according to P = R - G + L;
Electric field strength control method including. a hardware resource for wireless communication that can be reconfigured by changing software; a memory that stores software for making the hardware resource compatible with wireless communication; A software defined radio comprising a control unit that reconfigures hardware resources and an antenna that transmits and receives wireless signals,
a first memory area that stores antenna gain information that is a relationship between the gain and frequency of the antenna;
and a second memory area storing tolerance information that is a relationship between the tolerance value of electric field strength specified for the wireless station and the frequency,
The control unit includes:
a selection process for selecting a communication method and frequency band to be used for communication;
processing for configuring a communication line using the communication method and the frequency band;
A process of calculating a specified distance propagation loss L occurring in the frequency band at a position separated from the antenna by a distance specified as a position at which the electric field strength to be compared with a tolerance value R that the wireless station should satisfy;
a gain reading process of reading out a gain G exhibited by the antenna in the frequency band from the first memory area;
a process of reading a tolerance value R in the frequency band from the second memory area;
A process of calculating an upper limit value of transmission power P according to P = R - G + L,
A software defined radio that runs A field strength control program comprising a program for causing a computer to realize the functions of the software defined radio according to claim 7.

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