JP2013157771A - Radio communication system and radio communication method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication system which is suitable for preventing interferences in radio communication performed.SOLUTION: In the radio communication system, a GPS receiving unit 11 detects the location of a mobile station 1. On the basis of the detected location of the mobile station 1, a transmission power control unit 14 determines whether a prescribed condition for controlling the transmission power of the mobile station 1 is satisfied. When the prescribed condition is determined to be satisfied, the transmission power control unit 14 controls the transmission power of the mobile station 1 so that the power of a transmission wave from the mobile station 1 at the position of a receiving station which could suffer interferences by the transmission wave does not exceed a permissible interference power at the receiving station.

Description

  The present invention relates to a wireless communication system, a wireless communication method, and a program.

  In a wireless communication system including a movable wireless station (mobile station), the communication state changes variously according to the position of the mobile station. For this reason, various techniques for performing wireless communication in a suitable communication state regardless of changes in the position of the mobile station have been developed.

  For example, in Patent Document 1, a mobile station (portable station) detects the position of its own station, and transmits its own transmission power to an appropriate transmission power calculated based on the detected position of the own station and the antenna directivity characteristics of the satellite. A satellite communication system for controlling power is disclosed. With this technology, it is possible to control the transmission power to an appropriate value according to the change in the communication state caused by the change in the antenna directivity characteristic of the satellite depending on the position of the mobile station, which is suitable regardless of the position of the mobile station. Wireless communication can be performed in the communication state.

Japanese Patent Laid-Open No. 9-8721

  In the satellite communication system as described above, as a result of the movement of the mobile station, the mobile station may be located in the vicinity of another receiving station that is not related to communication, and the transmission wave from the mobile station may cause interference to the other receiving station. . However, Patent Document 1 does not disclose a control technique for preventing interference with other receiving stations not related to communication. Therefore, there has been a demand for a technique for performing wireless communication while appropriately preventing interference according to the position of the mobile station with respect to a receiving station that may receive interference due to a transmission wave from the mobile station.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a wireless communication system, a wireless communication method, and a program suitable for performing wireless communication while preventing interference. .

  To achieve the above object, a wireless communication system according to a first aspect of the present invention controls a transmission power of a mobile station based on a detection unit that detects the position of the mobile station and the detected position of the mobile station. A determination unit that determines whether or not a predetermined condition to be satisfied is satisfied, and a position of a reception station that may be interfered by a transmission wave from the mobile station when the determination unit determines that the predetermined condition is satisfied And a control unit that controls the transmission power of the mobile station so that the power of the transmission wave at the mobile station does not exceed the allowable interference power of the receiving station.

  According to the present invention, it is possible to provide a wireless communication system, a wireless communication method, and a program suitable for performing wireless communication while preventing interference.

It is a figure for demonstrating the outline | summary of the radio | wireless communications system which concerns on embodiment of this invention. 1 is a block diagram showing a schematic configuration example of a radio communication system according to a first embodiment. 3 is a block diagram showing an example of a physical configuration of a mobile station apparatus according to Embodiment 1. FIG. It is a figure which shows an example of the data of the other receiving station stored in the database of a ground station. It is a figure which shows an example of a prohibition area | region. (A) is a figure showing an example of a control field. (B) is a figure which shows an example of the correspondence of a control area | region and the allowable value of transmission power. 6 is a flowchart illustrating an example of operation of transmission power control processing according to Embodiment 1; It is a figure which shows another example of a prohibition area | region. (A) is a figure showing another example of a control field. (B) is a figure which shows another example of the correspondence of a control area | region and the allowable value of transmission power. 5 is a diagram for illustrating an overview of a radio communication system according to Embodiment 2. FIG. 6 is a block diagram illustrating a schematic configuration example of a radio communication system according to Embodiment 2. FIG. 6 is a flowchart illustrating an example of operation of transmission power control processing according to the second embodiment. It is a figure for demonstrating a mode that a transmission wave is shielded. 6 is a block diagram illustrating a schematic configuration example of a radio communication system according to Embodiment 3. FIG. It is a figure which shows an example of the correspondence of a modulation system and required CN ratio.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent parts are denoted by the same reference numerals.

Embodiment 1 FIG.
As shown in FIG. 1, the radio communication system according to the present embodiment is realized in a satellite communication system in which a mobile station 1 communicates with a ground station 3 via a communication satellite 2.

  The mobile station 1 is a wireless station that can move. In the present embodiment, the mobile station 1 is mounted on a helicopter as shown in FIG. 1 and can move in the air. The mobile station 1 includes a wireless communication device for performing wireless communication with the communication satellite 2, and exchanges data with the ground station 3 via the communication satellite 2. The satellite communication system in the present embodiment is a so-called helisat communication system (a helicopter-mounted satellite communication system), and the mobile station 1 uses the communication satellite 2 to acquire data acquired at the destination while moving in various places. 3 is provided. By passing through the communication satellite 2, it is affected by the positional relationship between the mobile station 1 and the ground station 3, such as when the mobile station 1 is hidden behind a mountain shadow and cannot transmit and receive radio waves to and from the ground station 3. Instead, communication is possible between the mobile station 1 and the ground station 3.

  The communication satellite 2 is an artificial satellite launched into outer space for the purpose of wireless communication. The communication satellite 2 includes a wireless communication device for performing wireless communication using radio waves such as millimeter waves, centimeter waves, and microwaves, and wirelessly communicates with the mobile station 1 and the ground station 3 while orbiting outside the atmosphere. I do. In the present embodiment, the communication satellite 2 mainly plays a role of relaying communication between the mobile station 1 and the ground station 3.

  The ground station 3 is a ground radio station for communication with the communication satellite 2. The ground station 3 includes, for example, a parabolic antenna, tracks the communication satellite 2 orbiting outside the atmosphere, and performs radio communication with the communication satellite 2 by transmitting and receiving radio waves in the direction of the communication satellite 2. In addition, the ground station 3 includes various data for managing the operation of the mobile station 1 and provides them to the mobile station 1 via the communication satellite 2 as necessary.

  On the other hand, the other receiving stations 4a to 4n shown in FIG. 1 are receiving stations different from the ground station 3 with which the mobile station 1 communicates. Among various receiving stations installed on the ground, the mobile stations This is a receiving station that may be interfered by a transmission wave from 1. That is, when the mobile station 1 moves in various places, if the mobile station 1 moves to the vicinity of a radio station that uses a frequency band that overlaps the frequency band of the transmission wave used by the mobile station 1, the transmission wave from the mobile station 1 is transmitted. Is expected to cause interference in the received wave at the receiving station. The other receiving stations 4a to 4n are receiving stations that the mobile station 1 may approach, and are receiving stations that use a frequency band that overlaps the frequency band of the transmission wave used by the mobile station 1. .

  Such other receiving stations 4a to 4n include, for example, radio astronomy, as long as the receiving station uses a frequency band that overlaps the frequency band of the transmission wave used by the mobile station 1 in addition to a communication radio station. Reception facilities are also included. Further, the other receiving stations 4a to 4n are not limited to fixed stations fixed at predetermined positions on the ground, but also include movable receiving facilities.

  As shown in FIG. 2, the mobile station device 10 is installed in the mobile station 1, and the ground station server 30 is installed in the ground station 3. Hereinafter, the configurations of the mobile station apparatus 10 and the ground station server 30 will be described with reference to FIG.

  The mobile station apparatus 10 includes a GPS receiver 11, a calculator 12, a storage unit 13, a transmission power controller 14, a transmitter 15, a data generator 16, and a receiver 17.

  The GPS receiver 11 has a function as a detector that detects the position of the mobile station 1. That is, the GPS receiver 11 receives a signal from a GPS (Global Positioning System) satellite orbiting the sky, and detects the current position (for example, latitude / longitude) of the mobile station 1 based on the received signal. To do. Information on the detected position is supplied to the calculation unit 12.

  The calculation unit 12 has a function of performing various calculations necessary for transmission power control processing. For example, the calculation unit 12 calculates the distance between the current position of the mobile station 1 supplied from the GPS reception unit 11 and the positions of the other reception stations 4a to 4n under the control of the CPU or the like. Based on the allowable interference power of the other receiving stations 4a to 4n, a transmission prohibition condition and a transmission power condition, which will be described later, are calculated. The data of the positions and allowable interference powers of the other receiving stations 4a to 4n used at this time are stored in advance in the database 33 of the ground station 3, received from the ground station 3 by the receiving unit 17, and supplied to the calculating unit 12. Is done. Data on the distance between the current position of the mobile station 1 calculated by the calculation unit 12 and the positions of the other receiving stations 4a to 4n is supplied to the transmission power control unit 14.

  The storage unit 13 is a storage area for storing various data necessary for transmission power control processing. For example, data of transmission prohibition conditions and transmission power conditions are stored in the storage unit 13. Here, the transmission prohibition condition and the transmission power condition are conditions determined in advance so that the transmission waves from the mobile station 1 to the communication satellite 2 do not interfere with the other receiving stations 4a to 4n. Will be described later.

  The transmission power control unit 14 has a function of controlling transmission power. The transmission power control unit 14 is configured so that the current position or transmission power of the mobile station 1 supplied from the calculation unit 12 satisfies the transmission prohibition condition or the transmission power condition stored in the storage unit 13 under the control of the CPU or the like. A function as a determination unit for determining whether or not, and a function as a control unit for controlling the transmission power of the mobile station 1 based on this determination. The transmission power control unit 14 controls the transmission power by transmitting a transmission stop control signal to the data generation unit 16 or transmitting a transmission power control signal to the transmission unit 15.

  The transmitter 15 has a function of transmitting a signal to the communication satellite 2. The transmission unit 15 transmits a signal to the communication satellite 2 with the transmission power controlled by the transmission power control unit 14. More specifically, the transmission unit 15 includes a modulation unit 15a, an upconverter 15b, and a power amplification unit 15c. The modulation unit 15a modulates a transmission wave having a predetermined frequency generated for transmission with a data signal supplied from the data generation unit 16, and generates an intermediate frequency signal. The up-converter 15b converts the intermediate frequency signal modulated by the modulation unit 15a into a radio frequency signal for radiating toward the communication satellite 2 as a radio wave. The power amplifying unit 15 c includes a variable resistor 15 d and adjusts the amplification factor by changing the resistance value of the variable resistor 15 d in accordance with the transmission power control signal from the transmission power control unit 14. As a result, the power amplifying unit 15 c amplifies the radio frequency signal supplied from the up-converter 15 b to the power necessary for radiating toward the communication satellite 2.

  The data generation unit 16 has a function of generating data to be transmitted to the communication satellite 2. The data generation unit 16 generates data to be provided to the ground station 3 such as observation data obtained by moving the mobile station 1 to various places, status data indicating the state of the mobile station 1, and the like. 15 is supplied. In addition, when receiving a transmission stop control signal from the transmission power control unit 14, the data generation unit 16 stops supplying data to the transmission unit 15. While the supply of data to the transmission unit 15 is stopped, the data generation unit 16 holds the generated data in a predetermined storage area until a signal indicating that transmission should be resumed is received, and transmission is resumed. After that, the data is supplied to the transmitter 15.

  The receiving unit 17 has a function of receiving a signal transmitted from the communication satellite 2. The receiving unit 17 receives the data of the positions and allowable interference powers of the other receiving stations 4 a to 4 n transmitted from the ground station 3 through the communication satellite 2. The received data is supplied to the calculation unit 12 and used for various calculations for transmission power control processing. Note that the receiving unit 17 in FIG. 2 is not directly connected to the antenna device 18 for easy understanding, but actually receives a signal from the communication satellite 2 using the antenna device 18.

  On the other hand, the ground station server 30 includes a ground station transmission unit 31, a ground station reception unit 32, and a database 33.

  The ground station transmission unit 31 has a function of transmitting a signal to the communication satellite 2. The ground station transmission unit 31 acquires, for example, the data of the positions and allowable interference powers of the other reception stations 4a to 4n stored in the database 33, and transmits the data to the communication satellite 2, so that these data are transmitted to the mobile station 1. To supply. In addition, the ground station transmission unit 31 transmits various information necessary for the operation of the mobile station 1 to the mobile station 1 via the communication satellite 2. 2 is not directly connected to the antenna device 34 for easy understanding, but actually transmits a signal to the communication satellite 2 using the antenna device 34.

  The ground station receiving unit 32 has a function of receiving a signal transmitted from the communication satellite 2. The ground station receiving unit 32 receives various data transmitted from the mobile station 1 to the ground station 3 via the communication satellite 2 using the antenna device 34.

  The database 33 is realized by a large-capacity storage device such as a hard disk drive, for example, and stores various data for the mobile station 1 to perform transmission power control processing. Specifically, as will be described in detail later, the database 33 stores data on the position and allowable interference power for the other receiving stations 4a to 4n.

  The mobile station apparatus 10 having the above functions is physically configured as shown in FIG. 3, and includes a CPU (Central Processing Unit) 10a, a ROM (Read Only Memory) 10b, and a RAM (Random Access Memory). 10c, input device 10d, output device 10e, transmission device 10f, and reception device 10g.

  The CPU 10a is interconnected with each component by a system bus which is a transmission path for transferring commands and data, and is in accordance with computer programs and various data necessary for operation control of the entire mobile station device 10 recorded in the ROM 10b. Operate. Then, the CPU 10a controls the operation of each unit while temporarily storing the computer program and data read from the ROM 10b and other data necessary for the progress of the processing in the RAM 10c.

  In the ROM 10b, various computer programs for operating the mobile station device 10 are recorded in advance, and various processes are executed while being read into the RAM 10c by the CPU 10a. The ROM 10b functions as, for example, the storage unit 13, records the transmission prohibition condition and the transmission power condition in advance, and the recorded transmission prohibition condition and the transmission power condition are read by the CPU 10a, and is transmitted to the transmission power control unit 14. Supplied.

  The RAM 10c is for temporarily storing data and programs, and holds programs and data read from the ROM 10b and other data necessary for the mobile station apparatus 10 to perform various processes.

  The input device 10d is composed of, for example, a keyboard and a mouse, and is used by an operator to input various operation instructions to the mobile station device 10. The output device 10e is composed of, for example, a CRT (Cathode Ray Tube), an LCD (Liquid Crystal Display), or the like, and displays images representing various types of information generated by the processing of the mobile station device 10. For example, the receiving device 10g may function as the input device 10d by allowing an instruction input to the mobile station device 10 to be received from the ground station 3 via the communication satellite 2. Further, the output device 10f may function as the output device 10e by displaying the output display for the processing of the mobile station device 10 on the ground station 3.

  The transmitting device 10f is for transmitting a radio signal in a frequency band determined in advance by the Radio Law and performing wireless communication with the communication satellite 2, and a circuit for generating a signal of a predetermined frequency, An amplifier circuit that increases power and a modulation circuit that modulates a carrier wave having a predetermined frequency with a signal including information to be transmitted are included. For example, the transmission device 10 f functions as the transmission unit 15 under the control of the CPU 10 a and transmits a transmission signal toward the communication satellite 2 via the antenna device 18.

  The receiving device 10g is for receiving a radio signal of a predetermined frequency band transmitted from the communication satellite 2, and amplifies a signal received via the antenna device 18 and demodulates the amplified signal. Thus, it is configured by a demodulator or the like that restores information. For example, the receiving device 10 g functions as the receiving unit 17 under the control of the CPU 10 a and receives a signal transmitted from the communication satellite 2 via the antenna device 18. In addition to receiving signals for wireless communication with the communication satellite 2, the receiving device 10g functions as the GPS receiving unit 11 under the control of the CPU 10a, for example, and receives signals from the GPS satellites. The current position information of the mobile station 1 is acquired.

  In addition, the mobile station device 10 may include a large-capacity storage device such as a hard disk drive and function as the storage unit 13. The mobile station device 10 may include a device in which an input unit such as a touch panel and a display unit are combined, and may function as the input device 10d or the output device 10e.

  Similarly to the mobile station device 10, the ground station server 30 includes a CPU, a ROM, a RAM, an input device, an output device, a transmission device, a reception device, a hard disk drive, and the like. Then, the CPU controls the operation of each unit such as the ground station transmission unit 31 and the ground station reception unit 32 while temporarily storing the computer program and data read from the ROM in the RAM.

  In the database 33 provided in the ground station server 30, as shown in FIG. 4, the position data and the data of allowable interference power are stored in advance for each of the other receiving stations 4 a to 4 n.

  Here, in the position data, latitude and longitude are used as objective information indicating the location where the other receiving stations 4a to 4n are located. In the example shown in FIG. 4, the other receiving station A is located at 35.65 degrees north latitude and 139.69 degrees east longitude, the other receiving station B is located 33.71 degrees north latitude and 138.02 degrees east longitude, The other receiving station C is located at 32.30 degrees north latitude and 133.56 degrees east longitude, and the other receiving station D is located at 38.06 degrees north latitude and 140.35 degrees east longitude. Thus, the database 33 stores the position of each of the other receiving stations 4a to 4n in association with the latitude / longitude.

  The position data stored in the database 33 is not limited to being expressed by latitude / longitude, but may be expressed by, for example, relative coordinates from a predetermined position.

  In addition to such position data, the database 33 of the ground station 3 stores allowable interference power data for each of the other receiving stations 4a to 4n. Here, the allowable interference power is also referred to as an allowable interference level, and is a value of power (typically an upper limit value) that allows each of the other receiving stations 4a to 4n to receive interference caused by transmission waves from radio stations other than its own station. ). That is, the allowable interference power indicates a limit of interference that can be allowed by a predetermined local station assuming that the other receiving stations 4a to 4n are each interfered by a transmission wave from a wireless station other than the local station. It is.

  Specifically, in the example illustrated in FIG. 4, the allowable interference power of the other receiving station A is −117 dBm / MHz, the allowable interference power of the other receiving station B is −51 dBm / MHz, and the other receiving station C The allowable interference power is -133 dBm / MHz, and the allowable interference power of the other receiving station D is -86 dBm / MHz. Thus, the database 33 stores data of allowable interference power unique to each of the other receiving stations 4a to 4n.

  The data about the other receiving stations 4a to 4n stored in the database 33 is updated as necessary. In particular, when a movable receiving station is included in the other receiving stations 4a to 4n, the position of the receiving station can change greatly. Therefore, the position data stored in the database 33 is, for example, periodically or the position of the movable receiving station is larger than a predetermined distance so that the position data of the appropriate receiving station can be provided to the mobile station device 10 as much as possible. It is updated when it changes.

  Based on the positions of the other receiving stations 4a to 4n and the allowable interference power, the calculation unit 12 of the mobile station apparatus 10 determines the transmission prohibition condition and the transmission power condition, and sets the transmission prohibition condition and the transmission power condition. Are stored in the storage unit 13.

  Here, the transmission prohibition condition means that transmission of transmission waves from the mobile station 1 should be stopped so that the transmission waves transmitted from the mobile station 1 to the communication satellite 2 do not interfere with the other receiving stations 4a to 4n. It is a condition. The transmission prohibition conditions are the positional relationship between the mobile station 1 and the other receiving stations 4a to 4n, the allowable interference power of the other receiving stations 4a to 4n, and the magnitude of the transmission power that may be used by the mobile station 1. It is determined based on.

  In order to determine the transmission prohibition condition, the receiving unit 17 of the mobile station device 10 transmits the data of the positions of the other receiving stations 4a to 4n and the allowable interference power stored in the database 33 of the ground station 3 via the communication satellite 2. Receive. And when the calculation part 12 considers the propagation loss by the distance of a transmission wave, and transmits a transmission wave with the transmission power which may be used in an own station, each position of other receiving stations 4a-4n An area (hereinafter referred to as a prohibited area) in which the power of the transmitted wave that has reached 1 exceeds the allowable interference power is obtained. The transmission prohibition condition is determined to be satisfied when the position of the mobile station 1 falls within the calculated prohibited area.

  For example, the prohibited area for the other receiving station 4a is a circular area whose distance from the other receiving station 4a is within the prohibited distance 51 as shown in FIG. When the mobile station 1 enters the inside of the prohibited area 50, that is, when the distance between the mobile station 1 and the other receiving station 4a is less than the prohibited distance 51, the transmission wave transmitted from the mobile station 1 is transmitted to the other receiving station 4a. Even if the frequency reaches, the power is not sufficiently attenuated, and the power of the transmission wave exceeds the allowable interference power of the other receiving station 4a. As a result, the other receiving stations 4a are affected by interference. On the other hand, when the mobile station 1 is located outside the prohibited area 50, that is, when the distance between the mobile station 1 and the other receiving station 4a exceeds the prohibited distance 51, the transmission wave from the mobile station 1 is used. Even if it is transmitted with the maximum power, it is attenuated until it reaches the other receiving station 4a, and the power of the transmission wave becomes less than the allowable interference power. As a result, the other receiving stations 4a are not affected by interference. For this reason, when the mobile station 1 is within the prohibited distance 51 from the other receiving station 4a, the transmission power control unit 14 stops transmission and prevents interference with the other receiving station 4a.

  Such a prohibited distance 51 is determined according to the allowable interference power unique to the other receiving stations 4a to 4n. For example, the forbidden distance 51 of a receiving station having a relatively large allowable interference power is larger than the forbidden distance 51 of a receiving station having a relatively small allowable interference power. The calculation unit 12 obtains the forbidden area 50 based on the forbidden distance 51 for each of the other receiving stations 4a to 4n. The obtained prohibited area 50 is held in the storage unit 13 as a transmission prohibition condition.

  The transmission power condition is for preventing other receiving stations 4a to 4n from receiving interference due to the transmission wave transmitted from the mobile station 1 to the communication satellite 2 as in the transmission prohibition condition. The condition is a condition for stopping transmission from the mobile station 1, whereas the transmission power condition is a condition for determining a power value for controlling the transmission power of the mobile station 1. That is, the transmission power condition is a condition for enabling the mobile station 1 to transmit a transmission wave with a transmission power that does not interfere with the other receiving stations 4a to 4n. Either one of the transmission prohibition condition and the transmission power condition can be selected by an operator, for example, and either condition is selected and used depending on the situation.

  Specifically, in order to determine the transmission power condition, the receiving unit 17 of the mobile station apparatus 10 uses the data of the positions of the other receiving stations 4a to 4n and the allowable interference power stored in the database 33 of the ground station 3, Receive via the communication satellite 2. Then, the calculation unit 12 determines a plurality of regions (hereinafter referred to as control regions) based on the positions of the other receiving stations for each of the other receiving stations 4a to 4n, and moves to each of the determined plurality of control regions. The transmission power allowable value that can be used by the station 1 is associated. The transmission power condition is that the position of the mobile station 1 enters one of a plurality of defined control areas, and the transmission power of the mobile station 1 corresponds to the transmission power associated with the control area that enters the inside. It is defined as being satisfied when the allowable value is exceeded.

  Specifically, as shown in FIG. 6A, the control region for the other receiving station 4a is formed by three concentric circles centered on the position of the other receiving station 4a and having radii of control distances 61a to 61c, respectively. A description will be given by taking as an example a case defined by three divided areas. The control area 60a is a donut-shaped area in which the distance from the position of the other receiving station 4a is less than the control distance 61a and equal to or greater than the control distance 61b. The control area 60b has a distance from the position of the other receiving station 4a. It is a donut-shaped area that is less than the control distance 61b and greater than or equal to the control distance 61c, and the control area 60c is a circular area that is less than the control distance 61c from the position of the other receiving station 4a.

  And the calculation part 12 considers the propagation loss by the distance of a transmission wave, and calculates the allowable value of the transmission power of the mobile station 1 about each of these three control area | regions 60a-60c. Here, the permissible value of the transmission power is used by the mobile station 1 in the region where the power of the transmission wave that has reached the position of the other receiving station 4a does not exceed the allowable interference power of the other receiving station 4a. This is a possible transmission power value (typically an upper limit value).

  More specifically, with reference to the example of FIG. 6B, the calculation unit 12 causes the three control regions 60a to 60c to have 100 W and 50 W, respectively, so as to be inversely correlated with the distances from the other receiving stations 4a. , 20 W is allowed. That is, in the control area 60a that is relatively far from the other receiving stations 4a than in the other areas, the degree of propagation loss due to the distance of the transmission wave is large, so that the allowable value is relatively larger than the other areas of 100W. Are associated. Conversely, in the control region 60c that is relatively close to the position of the other receiving station 4a than in the other regions, the degree of propagation loss due to the distance of the transmission wave is small, so that it is relatively smaller than the other region of 20W. Allowable values are associated.

  It should be noted that the allowable value of the transmission power shown in FIG. 6B is for ease of explanation, and various other values are determined according to how to define the control areas 60a to 60c, allowable interference power, and the like. May be used. Further, the number of control areas 60 is not limited to three as described above, and may be one or two, or more control areas 60 may be defined.

  The calculation unit 12 determines such control areas 60a to 60c for each of the other receiving stations 4a to 4n, calculates an allowable value of transmission power for each of the determined control areas 60a to 60c, and sets the transmission power condition as a transmission power condition. Stored in the storage unit 13. Since the other receiving stations 4a to 4n have different inherent allowable interference powers, the size of the calculated allowable value is different for each of the other receiving stations 4a to 4n. When the mobile station 1 enters one of the control areas 60a to 60c, the transmission power control unit 14 controls the transmission power so as not to exceed the allowable value associated with the control area in which the mobile station 1 is located, The interference with other receiving stations 4a to 4n is prevented.

  Note that such processing for determining the transmission prohibition condition or the transmission power condition may not be performed in the mobile station apparatus 10. That is, for example, an information processing device different from the mobile station device 10 acquires the data of the positions and allowable interference powers of the other receiving stations 4a to 4n from the database 33 of the ground station 3, and prohibits transmission based on the acquired data. Conditions or transmission power conditions may be determined, and the mobile station apparatus 10 may perform only the process of storing the predetermined transmission prohibition conditions or transmission power conditions in the storage unit 13.

  Next, transmission power control processing of the radio communication system according to the present embodiment will be described with reference to the flowchart of FIG. As shown in FIG. 7, the transmission power control process in the present embodiment is divided into a process on the mobile station 1 side and a process on the ground station 3 side.

  The transmission power control process shown in this flowchart is performed while the mobile station 1 is moving between various places while transmitting a transmission wave to the communication satellite 2, for example, at a regular timing or the mobile station 1 Is started at the timing when the position has moved by a predetermined distance or more.

  When the process is started, first, in the process on the mobile station 1 side, the GPS receiver 11 of the mobile station apparatus 10 detects the position of the own station (step S101). That is, the GPS receiving unit 11 receives a signal from a GPS satellite, and detects the current position of the mobile station 1 as, for example, latitude / longitude information based on the received signal. The detected position data is temporarily held in the RAM 10c or the like.

  When the GPS receiving unit 11 detects the position of the mobile station 1, next, in the mobile station 1, the transmission unit 15 of the mobile station device 10 sends the position data of the other receiving stations 4 a to 4 n to the ground station 3. An acquisition request is transmitted (step S102). That is, the transmitter 15 generates a request signal for acquiring data on the positions of the other receiving stations 4 a to 4 n stored in advance in the database 33 of the ground station 3, and transmits the ground station via the communication satellite 2. Send to 3.

  On the other hand, in the processing on the ground station 3 side, the ground station receiving unit 32 of the ground station server 30 receives the acquisition request transmitted from the mobile station 1 (step S103). Specifically, in the ground station 3, the ground station receiving unit 32 determines whether the acquisition request transmitted from the mobile station 1 is included in the signal received from the communication satellite 2. Wait for an acquisition request. When the ground station receiving unit 32 actually receives the acquisition request, the processing on the ground station 3 side proceeds to the following step S104.

  When the ground station receiving unit 32 receives the acquisition request, in the ground station 3, the ground station transmitting unit 31 of the ground station server 30 acquires the position data of the other receiving stations 4a to 4n from the database 33 (step S104). And the ground station transmission part 31 transmits the acquired position data of the other receiving stations 4a-4n to the mobile station 1 (step S105). That is, the ground station transmission unit 31 accesses the database 33 and acquires data on the positions of the other receiving stations 4a to 4n stored in advance. Then, the ground station transmission unit 31 generates a signal including the acquired position data of the other receiving stations 4 a to 4 n as a response to the received acquisition request, and transmits the signal to the mobile station 1 via the communication satellite 2. After the process of step S105 is completed, the process on the ground station 3 side ends.

  The ground station transmission unit 31 does not have to acquire data about all of the other reception stations 4 a to 4 n from the database 33 and transmit the data to the mobile station 1. For example, the ground station transmission unit 31 obtains only data of reception stations in the vicinity of the current position of the mobile station 1, thereby narrowing down to only reception stations that may be interfered by transmission waves from the mobile station 1. May be acquired. Specifically, the ground station receiving unit 32 receives the detected current position data of the mobile station 1 together with the acquisition request, and the ground station transmitting unit 31 is in the vicinity of the current position of the mobile station 1, for example, Only data of a receiving station within a predetermined distance from the current position of the mobile station 1 may be acquired and transmitted to the mobile station 1.

  In the ground station 3, the processes of steps S103 to S105 are repeated as necessary. Specifically, the ground station receiving unit 32 continuously waits for an acquisition request from the mobile station 1. Each time the ground station receiving unit 32 receives the acquisition request, the ground station transmitting unit 31 acquires the position data of the other receiving stations 4 a to 4 n from the database 33 and transmits it to the mobile station 1.

  When the ground station transmission unit 31 transmits the acquired data, the reception unit 17 of the mobile station device 10 receives the position data of the other reception stations 4a to 4n transmitted from the ground station 3 (step S106). Specifically, in the mobile station 1, the receiving unit 17 determines whether or not the signal received from the communication satellite 2 includes a response from the ground station 3 to the acquisition request transmitted by the local station. The position data of the receiving stations 4a to 4n are awaited. When the receiving unit 17 actually receives the position data of the other receiving stations 4a to 4n, the processing on the ground station 3 side proceeds to the following step S107.

  When the receiving unit 17 receives the position data of the other receiving stations 4a to 4n, the calculating unit 12 of the mobile station apparatus 10 next calculates the distance from the position of the own station to the positions of the other receiving stations 4a to 4n. (Step S107). That is, the calculation unit 12 determines the position of its own station based on the current position data of the mobile station 1 detected in step S101 and the position data of the other receiving stations 4a to 4n received in step S106. To the positions of the other receiving stations 4a to 4n is calculated for each of the other receiving stations 4a to 4n.

  Next, the transmission power control unit 14 of the mobile station device 10 determines whether or not the current control mode is the transmission prohibition mode (step S108). Here, the transmission prohibition mode is a mode in which the transmission prohibition condition is used among the two conditions of the transmission prohibition condition and the transmission power condition stored in the storage unit 13. On the other hand, of the two conditions, the mode in which the transmission power condition is used is hereinafter referred to as a transmission power mode. Of these two conditions, the transmission power control unit 14 selects the transmission prohibition condition when the current control mode is the transmission prohibition mode, and transmits the transmission power condition when the current control mode is the transmission power mode. Are used for transmission power control processing.

  When it is determined that the current mode is the transmission prohibition mode (step S108; YES), the transmission power control unit 14 determines whether or not the current position of the mobile station 1 satisfies the transmission prohibition condition (step S109). . That is, the transmission power control unit 14 reads out the transmission prohibition condition stored in the storage unit 13, that is, the data in the prohibition area 50 associated with each of the other receiving stations 4 a to 4 n in advance, and the current mobile station 1. It is determined whether or not the position is inside the prohibited area 50 of any of the other receiving stations 4a to 4n.

  More specifically, since the forbidden area 50 is a circular area having a radius around the position of each of the other receiving stations 4a to 4n as shown in FIG. The power control unit 14 determines whether or not each of the distances from the local station to the other receiving stations 4a to 4n calculated in step S107 is smaller than the forbidden distance 51 of the corresponding other receiving station. Then, when the calculated distance is smaller than the position prohibition distance 51 of the corresponding other receiving station, the transmission power control unit 14 has the current position of the mobile station 1 inside the prohibited area 50, that is, It is determined that the transmission prohibition condition is satisfied.

  When it is determined that the current position of the mobile station 1 satisfies the transmission prohibition condition (step S109; YES), that is, the current position of the mobile station 1 is in the prohibited area 50 of any of the other receiving stations 4a to 4n. If it is determined that it is inside, the transmission power control unit 14 stops transmission (step S110). That is, when the current position of the mobile station 1 is inside the prohibited area 50, when a transmission wave is transmitted from the mobile station 1 toward the communication satellite 2 with normal transmission power, It will interfere with the receiving station. In order to prevent this, the transmission power control unit 14 reduces the value of the transmission power to zero so that the transmission wave is not transmitted.

  Specifically, the transmission power control unit 14 sends a transmission stop control signal to the data generation unit 16 so that the data generated by the data generation unit 16 is not supplied to the transmission unit 15. Data generated after receiving the transmission stop control signal is held in a storage area such as the RAM 10c until a signal to resume transmission is received.

  On the other hand, when it is not determined that the current position of the mobile station 1 satisfies the transmission prohibition condition (step S109; NO), that is, the current mobile station 1 position is in which prohibited area of the other receiving stations 4a to 4n. If it is determined that it is not even inside 50, it is assumed that it does not interfere with any of the other receiving stations 4a to 4n, so the transmission power control unit 14 skips the process of step S110. And do not stop sending.

  On the other hand, the transmission power control process in the transmission power mode will be described below with respect to the transmission power control process in the transmission prohibition mode. In step S108, when it is determined that the current mode is not the transmission prohibition mode (step S108; NO), that is, when it is determined that the current mode is the transmission power mode, the transmission power control unit 14 determines that the transmission power of the current mobile station 1 is It is determined whether or not a transmission power condition is satisfied (step S109).

  That is, the transmission power control unit 14 reads out the data of the control areas 60a to 60c previously associated with the other receiving stations 4a to 4n from the storage unit 13, and the current position of the mobile station 1 is changed to the other receiving stations 4a to 4n. It is determined whether or not it is inside one of the control areas 60a to 60c of the stations 4a to 4n. When it is determined that the current position of the mobile station 1 is inside one of the control areas 60a to 60c, the transmission power control unit 14 associates with the control area determined to be inside. The permissible transmission power value is read from the storage unit 13 to determine whether or not the current transmission power of the mobile station 1 exceeds the read permissible value. The transmission power condition is satisfied when the current transmission power of the mobile station 1 exceeds the read allowable value.

  This will be described more specifically with reference to FIGS. 6 (a) and 6 (b). In the example shown in FIG. 6A, the control areas 60a to 60c are areas divided by three concentric circles centered on the position of the other receiving station 4a and having radii of control distances 61a to 61c, respectively. . Therefore, the transmission power control unit 14 compares the distances from the own station to the other receiving stations 4a to 4n calculated in step S107 with the control distances 61a to 61c of the corresponding other receiving stations. Then, the transmission power control unit 14 determines whether or not the current position of the mobile station 1 is inside any one of the control areas 60a to 60c based on the comparison result.

  For example, when the distance from the mobile station 1 to the other receiving station 4a is larger than the maximum control distance 61a among the three control distances 61a to 61c, the current position of the mobile station 1 is in the control areas 60a to 60c. The transmission power condition is not satisfied because it is outside any region. On the other hand, when the distance from the position of the mobile station 1 to the position of the other receiving station 4a is smaller than the control distance 61a, the current position of the mobile station 1 is inside any one of the control areas 60a to 60c. Will enter. In this case, the transmission power control unit 14 determines in which of the control areas 60a to 60c the current mobile station 1 is located, the distance from the mobile station 1 to the other receiving stations, and the control distances 61a to 61c. Judgment based on the comparison.

  And the transmission power control part 14 acquires the data of the allowable value of the transmission power previously matched with the control area | region where the mobile station 1 is located from the memory | storage part 13, and the present transmission power exceeds the acquired allowable value It is determined whether or not. Specifically, using the example shown in FIG. 6B, the transmission power control unit 14 acquires an allowable value of 100 W when the position of the mobile station 1 is inside the control region 60a. When it is inside the control area 60b, an allowable value of 50W is acquired, and when it is inside the control area 60c, an allowable value of 20W is acquired, and the current transmission power exceeds the acquired allowable value. It is determined whether or not. When it is determined that the current transmission power exceeds the acquired allowable value, the transmission power condition is satisfied.

  Returning to the flowchart of FIG. 7, when it is determined that the current transmission power of the mobile station 1 satisfies the transmission power condition (step S111; YES), the transmission power control unit 14 does not exceed the acquired allowable value. The transmission power is controlled (step S112). That is, the transmission power control unit 14 lowers the transmission power to an allowable value or less in order to prevent interference with other receiving stations located in the vicinity. Specifically, the transmission power control unit 14 sends a transmission power control signal to the power amplification unit 15c of the transmission unit 15 and adjusts the amplification factor of the transmission power by changing the resistance value of the variable resistor 15d. Control not to exceed the acquired tolerance.

  On the other hand, if it is not determined that the transmission power of the current mobile station 1 satisfies the transmission power condition (step S111; NO), that is, which control region of the other receiving stations 4a to 4n is the current position of the mobile station 1 If it is determined that the current transmission power of the mobile station 1 is not within the 60a to 60c, or is less than or equal to the allowable value of the transmission power associated with the control region within the Therefore, the transmission power control unit 14 skips the process of step S112 and does not control the transmission power because it is assumed that no interference is caused to any of the receiving stations 4a to 4n.

  After the transmission power control process based on the transmission prohibition condition or the transmission power condition as described above, the transmission power control process of the radio communication system according to the present embodiment ends.

  Since the mobile station 1 can move to various places, the above-described transmission power control process is performed, for example, so as not to interfere with any of the other receiving stations 4a to 4n at the destination. It is typically performed repeatedly or repeatedly every time the mobile station 1 moves more than a predetermined distance.

  As described above, the radio communication system according to the present embodiment has the transmission prohibition condition and the transmission power condition for each of the other receiving stations 4a to 4n that may be interfered by the transmission wave from the mobile station 1. Are stored in the storage unit 13 in advance. Then, it is determined whether or not the current position of the mobile station 1 satisfies the transmission prohibition condition, or whether or not the current transmission power of the mobile station 1 satisfies the transmission power condition. Control transmission power. As a result, even if the mobile station 1 moves in various places and moves to the vicinity of any of the other receiving stations 4a to 4n that are not involved in wireless communication with the mobile station 1, the transmission power is automatically controlled. Therefore, wireless communication can be performed while preventing interference with other receiving stations.

  In the wireless communication system of the present embodiment, the receiving unit 17 receives a signal from the ground station 3 via the communication satellite 2 in order to control the transmission power of the mobile station 1, thereby The position data of the other receiving stations 4a to 4n stored in the database 33 are acquired. However, in the wireless communication system of the present invention, the process of acquiring the position data of the other receiving stations 4a to 4n stored in the database 33 of the ground station 3 (steps S102 to S106 in the flowchart of FIG. 7) is not executed. May be. For example, once the position data of the other receiving stations 4a to 4n is acquired from the database 33 of the ground station 3 and stored in the storage unit 13, the mobile station device 10 thereafter transmits the other receiving stations 4a to 4n. Need not be acquired from the database 33 of the ground station 3. Thereby, it is possible to control the transmission power quickly. In particular, when there is no movable receiving station among the other receiving stations 4a to 4n, the position data of the other receiving stations stored in the database 33 is less frequently updated. This is effective for transmission power control.

  In the radio communication system according to the present embodiment, data of two conditions, that is, a transmission prohibition condition and a transmission power condition are stored in the storage unit 13, and the mobile station apparatus 10 selects one of the two conditions. Used. However, the wireless communication system of the present invention holds data of these two conditions in advance and is not limited to selecting and using one of them, but holding only data of one of these two conditions in advance. In addition, it may be used. That is, the wireless communication system of the present invention may not always store the transmission prohibition condition data in the storage unit 13, for example, and may always control the transmission power according to the transmission power condition, or may store the transmission power condition in the storage unit 13. The data may not be stored, and transmission may always be stopped according to the transmission prohibition condition.

  Further, in the wireless communication system of the present embodiment, the prohibited area 50 that defines the transmission prohibition condition is represented as a circular area that is within the prohibited distance 51 from the position of each of the other receiving stations 4a to 4n. However, in the wireless communication system of the present invention, the area for defining the transmission prohibition condition is not limited to the circular area, but may be any area.

  For example, as shown in FIG. 8, a transmission prohibition condition may be defined by a square prohibition area 80 including another receiving station 4a. In this case, when the transmission wave transmitted with a transmission power of a size that the local station may use reaches the other reception station 4a, the calculation unit 12 converts the power of the transmission wave to the other reception station. A region that exceeds the allowable interference power of 4a is obtained in advance as a square-shaped prohibited region 80. The storage unit 13 stores the calculated position data (for example, latitude / longitude information) of the four vertices of the square-shaped prohibited area 80. When the transmission power control process is executed, the transmission power control unit 14 compares the positions of the four vertices stored in the storage unit 13 with the current position of the mobile station 1 detected by the GPS reception unit 11. Then, it is determined whether or not the position of the mobile station 1 is inside the prohibited area 80. When the position of the mobile station 1 is inside the prohibited area 80, the transmission prohibition condition is satisfied.

  Further, like the prohibited area, the control area is not limited to an area defined by a circular area. That is, in the wireless communication system of the present embodiment, the control areas 60a to 60c for determining the transmission power condition are three areas centered on the position of the other receiving station 4a and having the control distances 61a to 61c as radii, respectively. Represented as However, in the wireless communication system of the present invention, the region for determining the transmission power condition is not limited to a plurality of regions divided by concentric circles, and may be any region.

  For example, as shown in FIG. 9A, nine square control areas 90a to 90i arranged in a grid pattern may be used to define the transmission power condition. In this case, the calculation unit 12 is arranged such that the control area 90e including the other receiving station 4a is disposed in the center, and the other eight control areas 90a to 90d and 90f to 90i are disposed so as to surround the control area 90e. The control areas 90a to 90i are defined.

  Then, for example, as shown in FIG. 9B, the calculation unit 12 sets the allowable value of the transmission power of the mobile station 1 for each of these nine control regions 90a to 90i based on the propagation loss due to the transmission wave distance. Calculate and associate with each. More specifically, among the nine control areas 90a to 90i arranged in a grid, the four control areas 90a, 90c, 90g, and 90i arranged at the four corners are relative to the positions of the other receiving stations 4a. Away. For this reason, the calculation unit 12 associates these regions with a relatively large allowable value of 50 W than other regions. The calculation unit 12 then associates an allowable value of 40 W with the four control areas 90b, 90d, 90f, and 90h that are next away from the position of the other receiving station 4a. Then, the calculation unit 12 associates a relatively small allowable value of 20 W with the control region 90e disposed at the center because it is relatively close to the position of the other receiving station 4a.

  9A and 9B, the number and size of the control areas, the arrangement method, the allowable value of the transmission power associated with each, etc. are only examples, and the radio of the present invention. In a communication system, in order to determine transmission power conditions, various numbers and sizes of control areas may be arranged in various ways, and various allowable values of transmission power may be associated with each. For example, more control areas are defined, and transmission power allowable values having different magnitudes are associated with the control areas, thereby enabling more precise control of the transmission power of the mobile station 1.

  Further, the prohibited area or the control area may be determined by including not only two-dimensional position data such as latitude / longitude but also vertical position data in a three-dimensional space. For example, the database 33 of the ground station server 30 stores in advance position data including vertical position data in the three-dimensional space, that is, altitude (elevation) information, for the other receiving stations 4a to 4n. And the calculation part 12 of the mobile station apparatus 10 determines a prohibition area | region and a control area | region as a three-dimensional area | region based on the positional data containing the height information about the other receiving stations 4a-4n acquired from the database 33, The data is stored in the storage unit 13 as data for determining the transmission prohibition condition and the transmission power condition. On the other hand, in the transmission power control process, the GPS receiving unit 11 detects the current position of the mobile station 1 including the altitude information, and the transmission power control unit 14 prohibits the detected current position of the mobile station 1. Whether it is inside the area or the control area is determined including altitude information, and the transmission power is controlled based on this determination.

  For example, when the mobile station 1 is flying at an altitude relatively far from the ground surface, even if the mobile station 1 is located near the latitude / longitude of any of the other receiving stations 4a to 4n, The possibility that the transmission wave interferes with the other receiving station is relatively low. Therefore, the forbidden area and the control area calculated in consideration of the altitude information are more compact than those calculated without considering the altitude information, and the area in which the mobile station 1 can transmit can be expanded. it can.

Embodiment 2. FIG.
Hereinafter, the radio communication system according to Embodiment 2 of the present invention will be described in detail.

  The radio communication system according to the first embodiment detects the position of the mobile station 1 and transmits the mobile station 1 based on the determination whether the detected position has entered a predetermined prohibited area or control area. Power was controlled. On the other hand, the radio communication system according to the present embodiment detects not only the position of mobile station 1 but also the direction, the distance from the position of mobile station 1 to the positions of other receiving stations 4a to 4n, and transmission. The transmission power is controlled based on the wave direction dependency.

  For example, assume that the mobile station 1, the communication satellite 2, and the other receiving station 4a are in a positional relationship as shown in FIG. The transmission wave from the mobile station 1 is transmitted toward the communication satellite 2, but also propagates in the direction toward the other reception station 4a that is off the off-axis angle θ from the directivity direction of the transmission wave. Further, the transmission wave is attenuated according to the propagation distance D from the position of the mobile station 1 to the position of the other receiving station 4a. The radio communication system according to the present embodiment calculates the power of the transmission wave at the position of the other receiving station 4a based on the direction dependency of the transmission wave and the propagation distance D, and propagates the power of the transmitted wave. The transmission power is controlled so that does not exceed the allowable interference power of each of the other receiving stations 4a to 4n.

  As shown in FIG. 11, the radio communication system according to the present embodiment is similar to the first embodiment described above, and the mobile station device 10 installed in the mobile station 1 and the ground station server 30 installed in the ground station 3. And.

  The mobile station apparatus 10 includes a GPS receiver 11, a calculator 12, a storage unit 13, a transmission power controller 14, a transmitter 15, a data generator 16, and a receiver 17. In the following, differences from the first embodiment will be mainly described for each of these parts.

  The GPS receiving unit 11 detects the current position of the mobile station 1 in the first embodiment, but further detects the current direction of the mobile station 1 (for example, an azimuth angle with reference to east, west, south, and north) in the present embodiment. To do. That is, the GPS receiving unit 11 receives a signal from a GPS satellite and detects the current direction of the mobile station 1 moving to various places, that is, which direction it is facing, based on the received signal. .

  Note that the orientation of the mobile station 1 is not limited to detection based on a signal from a GPS satellite. For example, the mobile station 1 includes an orientation sensor such as a compass or an inclination sensor such as a gyro, and the orientation of the mobile station 1 It may be used for detection.

  In Embodiment 1, the calculation unit 12 calculates the distance between the mobile station 1 and the other receiving stations 4a to 4n. In the present embodiment, the calculation unit 12 further functions as a directivity direction calculation unit that calculates the directivity direction of the transmission wave based on the direction of the mobile station 1 supplied from the GPS reception unit 11, and the antenna off-axis of the mobile station Function as a transmission power density calculation unit for calculating the transmission power density of the transmission wave based on the characteristics, a propagation loss calculation unit for calculating the propagation loss of the transmission wave, and other reception based on the transmission power density and the propagation loss It has a function as a power calculator that calculates the power of the transmission wave from the mobile station 1 at the positions of the stations 4a to 4n.

  The storage unit 13 stores data on the antenna off-axis characteristics of the mobile station 1. Here, the antenna off-axis characteristic is an index indicating how much electromagnetic waves are emitted in a direction deviating from the antenna axial direction. For example, the angle from the antenna axis (off-axis angle θ) It is represented by a correspondence relationship between the intensity ratio between the electromagnetic wave radiated in the angle direction and the electromagnetic wave radiated in the axial direction.

  The transmission power control unit 14 determines whether or not the power of the transmission wave from the mobile station 1 at the position of the other receiving stations 4a to 4n exceeds the allowable interference power of the other receiving stations 4a to 4n. And a function as a control unit that controls the transmission power of the mobile station 1 based on this determination, and transmits a transmission stop control signal or a transmission power control signal to the transmission unit 15 as in the first embodiment. Thus, the transmission power is controlled.

  On the other hand, the ground station server 30 includes a ground station transmission unit 31, a ground station reception unit 32, and a database 33. Each of these units basically functions in the same manner as each unit in the first embodiment. On the other hand, the database 33 of the ground station server 30 stores the data of the positions and allowable interference powers of the other receiving stations 4a to 4n in the first embodiment, but in the present embodiment, the other receiving stations 4a to 4n are further stored. 4n surrounding terrain data is stored.

  Here, the terrain data is data that mainly indicates an aspect such as the undulation of the ground surface, and is represented by, for example, the correspondence between latitude / longitude and altitude at each point on the ground surface. The database 33 stores terrain data in advance for each of the surrounding areas of the other receiving stations 4a to 4n.

  Next, transmission power control processing of the radio communication system according to the present embodiment will be described with reference to the flowchart of FIG. As shown in FIG. 11, the transmission power control process in this embodiment is divided into a process on the mobile station 1 side and a process on the ground station 3 side.

  The transmission power control process shown in this flowchart is performed while the mobile station 1 is moving between various places while transmitting a transmission wave to the communication satellite 2, for example, at a regular timing or the mobile station 1 Is started at the timing when the position has moved by a predetermined distance or more.

  When the process is started, first, in the process on the mobile station 1 side, the GPS receiving unit 11 of the mobile station apparatus 10 detects the position and orientation of the own station (step S201). That is, the GPS receiving unit 11 receives a signal from a GPS satellite and detects the current position and orientation of the mobile station 1 based on the received signal. The current position of the mobile station 1 is detected as three-dimensional information such as latitude, longitude, and altitude. The current orientation of the mobile station 1 is detected as azimuth information with reference to east, west, south, and north, for example. The detected position and orientation data are temporarily stored in the RAM 10c or the like.

  When the GPS receiving unit 11 detects the position of the mobile station 1, next, in the mobile station 1, the transmitting unit 15 of the mobile station device 10 acquires data of the other receiving stations 4 a to 4 n toward the ground station 3. A request is transmitted (step S202). That is, the transmitter 15 generates a request signal for acquiring data on the position, allowable interference power, and terrain for the other receiving stations 4a to 4n stored in the database 33 of the ground station 3 in advance. Then, the data is transmitted to the ground station 3 via the communication satellite 2.

  On the other hand, in the processing on the ground station 3 side, the ground station receiving unit 32 of the ground station server 30 receives the acquisition request transmitted from the mobile station 1 (step S203). Specifically, in the ground station 3, the ground station receiving unit 32 determines whether the acquisition request transmitted from the mobile station 1 is included in the signal received from the communication satellite 2. Wait for an acquisition request. When the ground station receiving unit 32 actually receives the acquisition request, the processing on the ground station 3 side proceeds to the following step S204.

  When the ground station receiving unit 32 receives the acquisition request, in the ground station 3, the ground station transmitting unit 31 of the ground station server 30 acquires the position, allowable interference power, and terrain data of the other receiving stations 4 a to 4 n from the database 33. (Step S204). Then, the ground station transmission unit 31 transmits the acquired data of the other reception stations 4a to 4n to the mobile station 1 (step S205). That is, the ground station transmission unit 31 accesses the database 33 and acquires data on the positions, allowable interference power, and terrain of the other reception stations 4a to 4n stored in advance. Then, the ground station transmission unit 31 generates a signal including the acquired data as a response to the received acquisition request, and transmits the signal to the mobile station 1 via the communication satellite 2. After the process of step S205 is completed, the process on the ground station 3 side ends.

  The ground station transmission unit 31 does not have to acquire data about all of the other reception stations 4 a to 4 n from the database 33 and transmit the data to the mobile station 1. For example, the ground station transmission unit 31 obtains only data of reception stations in the vicinity of the current position of the mobile station 1, thereby narrowing down to only reception stations that may be interfered by transmission waves from the mobile station 1. May be acquired. Specifically, the ground station receiving unit 32 receives the detected current position data of the mobile station 1 together with the acquisition request, and the ground station transmitting unit 31 is in the vicinity of the current position of the mobile station 1, for example, Only data of a receiving station within a predetermined distance from the current position of the mobile station 1 may be acquired and transmitted to the mobile station 1.

  In the ground station 3, the processes of steps S203 to S205 are repeated as necessary. Specifically, the ground station receiving unit 32 continuously waits for an acquisition request from the mobile station 1. Each time the ground station receiving unit 32 receives the acquisition request, the ground station transmitting unit 31 acquires data of the other receiving stations 4 a to 4 n from the database 33 and transmits the data to the mobile station 1.

  When the ground station transmission unit 31 transmits the acquired data, the transmission power control process returns to the process on the mobile station 1 side, and the reception unit 17 of the mobile station apparatus 10 receives the other reception stations 4a to 4a transmitted from the ground station 3. 4n data is received (step S206). Specifically, in the mobile station 1, the receiving unit 17 determines whether or not the signal received from the communication satellite 2 includes a response from the ground station 3 to the acquisition request transmitted by the local station. Data of the receiving stations 4a to 4n. When the receiving unit 17 actually receives the data of the other receiving stations 4a to 4n, the processing on the ground station 3 side proceeds to the following step S207.

  When the receiving unit 17 receives the data of the other receiving stations 4a to 4n, next, the calculation unit 12 of the mobile station apparatus 10 determines the distance from the position of the mobile station 1 to the positions of the other receiving stations 4a to 4n, that is, The propagation distance D is calculated (step S207). That is, the calculation unit 12 determines the position of its own station based on the current position data of the mobile station 1 detected in step S201 and the position data of the other receiving stations 4a to 4n received in step S206. To the positions of the other receiving stations 4a to 4n, the propagation distance D is calculated for each of the other receiving stations 4a to 4n.

  When the propagation distance D from the position of the own station to the positions of the other receiving stations 4a to 4n is calculated, the calculation unit 12 next determines the orientation of the mobile station 1 and the positional relationship between the mobile station 1 and the communication satellite 2. Based on the above, the directivity direction of the transmission wave transmitted from the mobile station 1 to the communication satellite 2 is calculated (step S208). That is, since the direction of the antenna device 18 for the transmission unit 15 of the mobile station 1 to efficiently transmit a transmission wave toward the communication satellite 2 depends on the current direction of the mobile station 1, the calculation unit 12 Using the current direction data of the mobile station 1 detected by the GPS receiver 11, the directivity direction of the transmission wave is calculated.

  After calculating the directivity direction of the transmission wave, the calculation unit 12 calculates the transmission power density radiated in the direction of the other receiving stations 4a to 4n when the transmission wave is transmitted in the calculated directivity direction ( Step S209). In general, the power of the transmission wave radiated from the antenna device 18 having directivity is the largest in the axial direction of the antenna, and becomes smaller as it deviates from the axis. The calculation unit 12 calculates how much the power of the transmission wave radiated in the direction of the other receiving stations 4a to 4n is weakened compared to the case where the power is radiated in the axial direction of the antenna.

  Specifically, the calculation unit 12 is based on the current position data of the mobile station 1 detected by the GPS reception unit 11 and the position data of the other reception stations 4 a to 4 n received from the ground station 3. The direction from the current position to each of the other receiving stations 4a to 4n is calculated. Then, the calculation unit 12 calculates the angle between the calculated direction from the current position of the mobile station 1 to each position of the other receiving stations 4a to 4n and the directivity direction of the transmission wave, that is, an off-axis angle. Calculate θ. And based on the antenna off-axis characteristic memorize | stored in the memory | storage part 13, the transmission power density when transmitting to the calculated off-axis angle (theta) is acquired. In general, the larger the off-axis angle θ, the smaller the transmission power density radiated in that direction.

  After calculating the transmission power density in the direction of the other receiving stations 4a to 4n, the calculation unit 12 calculates the propagation loss of the transmission wave (step S210). That is, the calculation unit 12 determines that the transmission wave is different from the position of the mobile station 1 based on the propagation distance D from the position of the mobile station 1 calculated in step S207 to each position of the other receiving stations 4a to 4n. The degree of attenuation is calculated up to the respective positions of the receiving stations 4a to 4n.

  At this time, the calculation unit 12 also uses the terrain data acquired from the database 33 of the ground station 3 to calculate the propagation loss of the transmission wave. For example, as shown in FIG. 13, when a mountain exists as the shield S between the position of the mobile station 1 and the positions of the other receiving stations 4a to 4n, the transmission wave is caused by the mountain. Because it is shielded, the degree of propagation loss is greater than when there are no mountains. Therefore, the calculation part 12 acquires the information of the shield S between the mobile station 1 and the other receiving stations 4a-4n based on the terrain data around the other receiving stations 4a-4n. And the calculation part 12 calculates the propagation loss of a transmission wave based on the information of the acquired shield S. FIG.

  When the propagation loss is calculated, the calculation unit 12 next calculates the transmission power density and propagation loss based on the calculated data of allowable interference power of the other receiving stations 4a to 4n acquired from the database 33 of the ground station 3. The power when the transmission wave transmitted from the mobile station 1 propagates to the respective positions of the other receiving stations 4a to 4n is calculated (step S211).

  That is, the calculation unit 12 calculates, based on the calculated transmission power density and propagation loss, the transmission power of the mobile station 1 and the power of the transmission wave propagated to the respective positions of the other receiving stations 4a to 4n. Calculate the ratio. And the calculation part 12 calculates the electric power of the transmission wave when it propagates to each position of the other receiving stations 4a-4n using the calculated ratio.

  When the power of the transmission wave when propagating to the respective positions of the other receiving stations 4a to 4n is calculated, the transmission power control unit 14 determines that the calculated power of the transmission wave is any one of the other receiving stations 4a to 4n. It is determined whether or not the interference power is exceeded (step S212). That is, in the mobile station apparatus 10, as a condition for controlling the transmission power of the mobile station 1, the allowable interference of the reception station to which the power of the transmission wave when propagating to the respective positions of the other reception stations 4a to 4n corresponds. A condition for controlling the transmission power when the power is exceeded is determined in advance and held in the storage unit 13 or the like. Then, the transmission power control unit 14 determines whether or not the calculated transmission wave power satisfies the held condition.

  When it is determined that the calculated transmission wave power exceeds the allowable interference power of any of the other receiving stations 4a to 4n (step S212; YES), the transmission power control unit 14 determines that the calculated transmission wave power is The transmission power is controlled so as not to exceed the allowable interference power (step S213). That is, the transmission power control unit 14 compares the calculated transmission wave power with the allowable interference power, and determines how much the transmission power is reduced so as not to interfere with the receiving station. Then, the transmission power control unit 14 sends a transmission power control signal to the power amplification unit 15c of the transmission unit 15, changes the resistance value of the variable resistor 15d, and adjusts the amplification factor of the transmission power, thereby adjusting the transmission power. Reduce. For example, when the power of the transmission wave when propagating to the position of any one of the other receiving stations 4a to 4n is twice the allowable interference power of the receiving station, the transmission power control unit 14 reduces transmission power in half.

  Alternatively, instead of sending the transmission power control signal to the transmission unit 15, the transmission power control unit 14 sends a transmission stop control signal to the data generation unit 16 so that the data generated by the data generation unit is not supplied to the transmission unit 15. Thus, transmission may be stopped.

  When the power of the transmission wave calculated for a plurality of receiving stations among the other receiving stations 4a to 4n exceeds the allowable interference power, the transmission power control unit 14 interferes with any receiving station. In order not to affect the transmission power, the transmission power is controlled so that the allowable interference power does not exceed the maximum allowable interference power of the receiving station.

  On the other hand, when it is determined that the calculated power of the transmission wave does not exceed any of the allowable interference powers of the other receiving stations 4a to 4n (step S212; NO), for any of the other receiving stations 4a to 4n Since it is assumed that no interference occurs, the transmission power control unit 14 skips the process of step S213 and does not control the transmission power.

  After the process as described above, the transmission power control process of the radio communication system according to the present embodiment ends.

  Since the mobile station 1 can move to various places, the above-described transmission power control process is performed, for example, so as not to interfere with any of the other receiving stations 4a to 4n at the destination. It is typically performed repeatedly or repeatedly every time the mobile station 1 moves more than a predetermined distance.

  As described above, the radio communication system according to the present embodiment detects the direction of the mobile station 1 in addition to the current position. Then, based on the propagation distance D and the direction dependency of the transmission wave, the power of the transmission wave when propagating to the positions of the other reception stations 4a to 4n is calculated, and the allowable interference power of the reception station corresponding to the calculated power The transmission power is controlled so as not to exceed. As a result, even if the mobile station 1 moves to any position, it is possible to more appropriately control the transmission power so as not to interfere with the other receiving stations 4a to 4n. Further, by detecting the direction of the mobile station 1, even if it is in the vicinity of the positions of the other receiving stations 4a to 4n, transmission can be performed without causing interference depending on the direction of the mobile station 1, so the mobile station 1 The effect of enlarging the transmittable area is obtained.

  Furthermore, the radio | wireless communications system which concerns on this Embodiment controls transmission power based also on the information of the shield S obtained from the topographical data around the other receiving stations 4a-4n. As a result, even in the vicinity of the positions of the other receiving stations 4a to 4n, transmission can be performed without causing interference depending on the surrounding terrain. Therefore, an effect of further expanding the transmission area of the mobile station 1 is obtained. It is done.

  In the wireless communication system of the present embodiment, the calculation unit 12 calculates the power when the transmission wave transmitted from the mobile station 1 propagates to the respective positions of the other receiving stations 4a to 4n, and transmits power control. The unit 14 controls the transmission power by determining whether or not the calculated transmission wave power exceeds the allowable interference power of any of the other receiving stations 4a to 4n (steps in the flowchart of FIG. 12). S211 to S213). However, for example, the calculation unit 12 calculates the upper limit value of the transmission power that can be used by the mobile station 1, and the transmission power control unit 14 determines whether or not the transmission power of the mobile station 1 exceeds the calculated upper limit value. By doing so, the transmission power may be controlled.

  Specifically, for example, the calculation unit 12 calculates the transmission power of the mobile station 1 based on the transmission power density and the propagation loss and the power of the transmission wave propagated to the respective positions of the other receiving stations 4a to 4n. A ratio is calculated, and using this ratio, an upper limit value of transmission power that can be used by the mobile station 1 so as not to exceed any allowable interference power of the other receiving stations 4a to 4n is calculated. Then, the transmission power control unit 14 may control the transmission power of the mobile station 1 so as not to exceed the calculated upper limit value. That is, in the radio communication system according to the present embodiment, whether or not the power of the transmitted wave that has propagated to the respective positions of the other receiving stations 4a to 4n exceeds the allowable interference power of each of the other receiving stations 4a to 4n. Any index may be used as long as it can be determined.

Embodiment 3 FIG.
Hereinafter, the radio communication system according to Embodiment 3 of the present invention will be described in detail.

  In the radio communication systems according to the first and second embodiments, the transmission power is controlled so that the other receiving stations 4a to 4n are not interfered by the transmission wave from the mobile station 1. On the other hand, the radio communication system according to the present embodiment further ensures the communication quality by changing the modulation method when controlling the transmission power.

  As shown in FIG. 14, the radio communication system according to the present embodiment is similar to the second embodiment described above, and the mobile station apparatus 10 installed in the mobile station 1 and the ground station server 30 installed in the ground station 3. And.

  The mobile station apparatus 10 includes a GPS receiver 11, a calculator 12, a storage unit 13, a transmission power controller 14, a transmitter 15, a data generator 16, and a receiver 17. The ground station server 30 includes a ground station transmission unit 31, a ground station reception unit 32, and a database 33. These units basically function in the same manner as the units in the second embodiment.

  On the other hand, mobile station apparatus 10 in the present embodiment further includes a modulation scheme changing unit 19. Further, the storage unit 13 in the present embodiment further stores modulation scheme candidate data in addition to the antenna off-axis characteristic data. The transmission power control unit 14 according to the present embodiment also has a function as a selection unit that selects a modulation scheme to be changed from the modulation scheme candidates stored in the storage unit 13. Is supplied to the modulation method changing unit 19.

  The modulation method changing unit 19 has a function as a changing unit that changes the modulation method. The modulation scheme changing unit 19 changes the modulation scheme to one modulation scheme selected from a plurality of modulation scheme candidates prepared in advance in accordance with the modulation scheme control signal from the transmission power control unit 14. The changed modulation scheme information is supplied to the modulation unit 15 a of the transmission unit 15 and reflected in the process of modulating the transmission wave with the data signal supplied from the data generation unit 16.

  A plurality of modulation scheme candidates for changing the modulation scheme are stored in the storage unit 13 in advance. Specifically, in the example illustrated in FIG. 15, the storage unit 13 includes 16 QAM (16 quadrature amplitude modulation), 8 PSK (8 phase-shift keying), QPSK (quadrature phase-shift keying), and BPSK (binary phase-shift keying). ) Are stored.

  Further, the storage unit 13 stores the required CN ratio in association with each of these four modulation schemes. Here, the CN (Carrier to Noise) ratio is the ratio of the magnitude of the carrier power and the noise power, and is one of the indexes indicating the quality of the transmitted signal. The required CN ratio is a limit CN ratio at which the receiver can stably demodulate the signal. If the CN ratio is smaller than the required CN ratio, it is difficult to transmit correct information.

  The required CN ratio generally becomes larger as the modulation method has a higher information rate, and the transmission signal is more susceptible to noise. Therefore, in order for the CN ratio of the transmission signal to be equal to or higher than the required CN ratio under a modulation scheme with a high information rate, it is necessary to transmit the signal with relatively large transmission power. For example, in the example of FIG. 15, the required CN ratio of 16QAM having the highest information rate among the four modulation scheme candidates is the maximum of 15 dB, and corresponds as the information rate decreases to 8PSK, QPSK, and BPSK. The required CN ratio gradually decreases, such as 10 dB, 6 dB, and 3 dB.

  In the radio communication system according to the present embodiment, similarly to the second embodiment, the transmission power control unit 14 of the mobile station apparatus 10 performs other reception based on the propagation distance D and the direction dependency of the transmission wave. The transmission power is controlled so as not to interfere with the stations 4a to 4n. On the other hand, in the radio communication system according to the present embodiment, the transmission power control unit 14 further stores a modulation scheme in which the CN ratio of the transmission wave transmitted with the controlled transmission power satisfies the required CN ratio. 13 is selected from four modulation scheme candidates stored in advance.

  Specifically, the transmission power control unit 14 compares the transmission power controlled so as not to interfere with the other receiving stations 4a to 4n and the power of the noise signal, and acquires the CN ratio of the transmission wave. Then, the transmission power control unit 14 specifies a required CN ratio that is maximum below the acquired CN ratio among the four required CN ratios, and selects a modulation scheme corresponding to the specified required CN ratio.

  For example, if the acquired CN ratio is 8 dB, the 16QAM and 8PSK modulation schemes are not selected because the calculated CN ratio is less than the required CN ratio of 15 dB and 10 dB, respectively. On the other hand, among the QPSK and BPSK modulation schemes associated with the required CN ratios of 6 dB and 3 dB that are equal to or less than the acquired CN ratio, the modulation of QPSK is associated with the required CN ratio of 6 dB having a larger required CN ratio. The method will be selected.

  When the modulation method is selected, the transmission power control unit 14 determines whether or not to change the modulation method by determining whether or not the selected modulation method is different from the current modulation method. When it is determined that the modulation method is to be changed, the transmission power control unit 14 sends a modulation method control signal to the modulation method change unit 19. Then, the modulation scheme changing unit 19 changes the modulation scheme to the selected modulation scheme. The changed modulation scheme information is supplied to the modulation section 15a and reflected in the transmission wave modulation processing.

  When the modulation method changing unit 19 changes the modulation method, the signal receiving side, that is, the demodulation method of the communication satellite 2 needs to be changed accordingly. Therefore, the modulation scheme information changed by the modulation scheme changing unit 19 is also supplied to the communication satellite 2 by the transmission wave before the modulation scheme is changed, and is reflected in the demodulation scheme of the receiving device of the communication satellite 2.

  As described above, the radio communication system according to the present embodiment, when controlling the transmission power so that the transmission wave from the mobile station 1 does not interfere with the other reception stations 4a to 4n, the CN of the transmission wave A modulation scheme in which the ratio is equal to or higher than the required CN ratio is selected from a plurality of modulation schemes held in advance, and the modulation scheme is changed to the selected modulation scheme. As a result, even when the transmission power is reduced so as not to interfere with the other receiving stations 4a to 4n and the CN ratio of the transmission wave is deteriorated, wireless communication is possible without degrading the communication quality as much as possible.

  The present invention can be variously modified and modified without departing from the broad spirit and scope of the present invention. The above-described embodiments are for explaining the present invention and do not limit the scope of the present invention.

  For example, the wireless communication system in the above embodiment is realized in a satellite communication system that performs wireless communication via the communication satellite 2. However, the wireless communication system of the present invention is not limited to the satellite communication system. For example, the wireless communication system of the present invention communicates via the communication satellite 2 such that the mobile station 1 directly performs wireless communication with the ground station 3 or wirelessly communicates with other mobile wireless stations. It doesn't have to be a thing. In other words, if the mobile station 1 is a system in which a transmission wave from the mobile station 1 when performing wireless communication may interfere with other receiving stations that are not originally involved in communication, the wireless of the present invention. A communication system can be applied.

  The wireless communication system in the above embodiment is realized in a so-called helisat communication system in which the mobile station 1 is mounted on a helicopter. However, the wireless communication system of the present invention can be applied to various mobile communication systems as well as the Helisat communication system. For example, the mobile station 1 is not limited to being mounted on a helicopter, but may be mounted on another aircraft such as an airplane or an airship. Further, the aircraft is not limited to an aircraft capable of flying, and may be mounted on a ship or a vehicle as long as it can move to various places.

  In addition, the wireless communication system in the above embodiment is composed of the mobile station device 10 and the ground station server 30 installed in the mobile station 1 and the ground station 3, respectively. However, the wireless communication system of the present invention is not limited to including the mobile station device 10 and the ground station server 30. For example, in the above embodiment, the mobile station device 10 is configured to include the database 33 provided in the ground station server 30 or necessary data among the data stored in advance in the database 33 is stored in the storage unit. The wireless communication system of the present invention may be configured by a single device called the mobile station device 10.

  Further, the other receiving stations 4a to 4n that may be interfered by the transmission wave from the mobile station 1 may be mounted on, for example, a vehicle, a ship, an aircraft, or the like and move in position. . In this case, the wireless communication system of the present invention obtains the latest information on where the movable receiving station is currently located so as not to interfere with such a movable receiving station. There is a need. For this reason, the wireless communication system of the present invention obtains the current position data of the movable receiving station, for example, periodically, and updates the position data stored in the database 33 to obtain the position data of the receiving station as much as possible. The latest information may be kept. Alternatively, the wireless communication system of the present invention obtains the position of the receiving station when the movable receiving station has moved more than a predetermined distance, and updates the position data stored in the database 33. The position data of the receiving station may be kept with a certain accuracy. With such a configuration, the wireless communication system of the present invention reduces the transmission power of the mobile station 1 so that it does not interfere with the destination receiving station even if the receiving station moves to various places. It becomes possible to control appropriately.

  In the above-described embodiment, the program executed by the CPU has been described as being stored in advance in a ROM, a storage unit, or the like. However, the present invention is not limited to this, and is for executing the above-described processing. This program may be applied to an existing general-purpose computer to function as the mobile station device 10 or the ground station server 30 according to the above embodiment.

  A method for providing such a program is arbitrary. For example, the program may be stored and distributed on a computer-readable recording medium (flexible disk, CD (Compact Disc) -ROM, DVD (Digital Versatile Disc) -ROM, etc.). Alternatively, the program may be stored in a storage on a network such as the Internet and provided by downloading it. Further, such a program may be provided as a single application software, or may be incorporated in the software of the device as one function of the device.

DESCRIPTION OF SYMBOLS 1 Mobile station 2 Communication satellite 3 Ground station 4a-4n Other receiving station 10 Mobile station apparatus 11 GPS receiving part 12 Calculation part 13 Memory | storage part 14 Transmission power control part 15 Transmission part 15a Modulation part 15b Up converter 15c Power amplification part 15d Variable Resistor 16 Data generation unit 17 Reception unit 18 Antenna device 19 Modulation method change unit 10a CPU
10b ROM
10c RAM
10d input device 10e output device 10f transmission device 10g reception device 30 ground station server 31 ground station transmission unit 32 ground station reception unit 33 database 34 antenna device 50 forbidden area 51 forbidden distance 60a-60c control area 61a-61c control distance 80 forbidden area 90a-90i control area

Claims (8)

A detection unit for detecting the position of the mobile station;
A determination unit that determines whether or not a predetermined condition for controlling transmission power of the mobile station is satisfied based on the detected position of the mobile station;
When the determination unit determines that the predetermined condition is satisfied, the power of the transmission wave at the position of the reception station that may be interfered by the transmission wave from the mobile station is the allowable interference power of the reception station. A control unit for controlling the transmission power of the mobile station so as not to exceed
A wireless communication system comprising: The receiving station is associated with a predetermined area based on the position of the receiving station and the allowable interference power,
The predetermined condition is satisfied when the position of the detected mobile station is within the area,
The control unit controls the transmission power of the mobile station to stop transmission of the mobile station when the determination unit determines that the predetermined condition is satisfied;
The wireless communication system according to claim 1. The receiving station is associated with a plurality of areas,
Each of the plurality of areas is associated with an allowable value of the transmission power of the mobile station that is determined in advance based on the distance from the area to the receiving station and the allowable interference power of the receiving station
The predetermined condition is that the detected position of the mobile station is inside any one of the plurality of areas, and an allowable value associated with the area where the mobile station is located inside is transmitted by the mobile station. Satisfied when power exceeds,
When the determination unit determines that the predetermined condition is satisfied, the control unit transmits the transmission power of the mobile station so as not to exceed an allowable value associated with a region where the mobile station is located inside. To control the
The wireless communication system according to claim 1. The detection unit further detects the orientation of the mobile station;
Based on the detected orientation of the mobile station, a directivity direction calculation unit that calculates the directivity direction of the transmission wave from the mobile station;
Transmission power density calculation for calculating the transmission power density of a transmission wave radiated from the detected mobile station position to the receiving station position based on the calculated directivity direction and the antenna off-axis characteristics of the mobile station And
A propagation loss calculation unit for calculating a propagation loss from the position of the detected mobile station to the position of the receiving station;
Based on the calculated transmission power density and the calculated propagation loss, a power calculator that calculates the power of the transmission wave at the position of the receiving station;
Further comprising
The predetermined condition is satisfied when the power of the calculated transmission wave exceeds the allowable interference power of the receiving station.
The wireless communication system according to claim 1. The propagation loss calculation unit calculates the propagation loss based on shielding information between the detected position of the mobile station and the position of the receiving station.
The wireless communication system according to claim 4. A selection unit that selects a modulation method in which a CN ratio of a transmission wave transmitted with the controlled transmission power is equal to or higher than a required CN ratio among a plurality of modulation methods;
A changing unit for changing a modulation method to the selected modulation method;
Further comprising
The radio | wireless communications system of any one of Claim 1 to 5. A detection step for detecting the position of the mobile station;
A determination step of determining whether or not a predetermined condition for controlling transmission power of the mobile station is satisfied based on the detected position of the mobile station;
When it is determined that the predetermined condition is satisfied by the determination step, the power of the transmission wave at the position of the reception station that may be interfered by the transmission wave from the mobile station is the allowable interference power of the reception station. Control step of controlling the transmission power of the mobile station so as not to exceed
A wireless communication method comprising: Computer
A detection unit for detecting the position of the mobile station;
A determination unit that determines whether or not a predetermined condition for controlling the transmission power of the mobile station is satisfied based on the detected position of the mobile station,
When the determination unit determines that the predetermined condition is satisfied, the power of the transmission wave at the position of the reception station that may be interfered by the transmission wave from the mobile station is the allowable interference power of the reception station. A control unit for controlling the transmission power of the mobile station so as not to exceed
Program to function as.

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