JP2005303669A - Radio lan system, transmission power control method, position managing method and transmission power control program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately control the transmission power of an access point and a client terminal and to reduce the power consumption of the access point and the client terminal. <P>SOLUTION: A GPS receiving part 21 receives a GPS signal and obtains access point position information. A GPS receiving part 31 receives the GPS signal and obtains terminal position information. A radio LAN client 30 transmits the terminal position information to a radio LAN access point 20. The radio LAN access point 20 determines a transmission power value on the basis of the access point position information and the terminal position information and controls the transmission power of respective radio LAN devices 20 and 30. Further, the radio LAN access point 20 is provided with a position information database 22 for storing position management information to collectively manage the positions of the respective radio LAN devices 20 and 30. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wireless LAN system, a transmission power control method, and a transmission power control program for controlling transmission power (output power) of a wireless LAN access point and a client terminal. The present invention also relates to a location management method for managing the locations of wireless LAN access points and client terminals.

  FIG. 9 is an explanatory diagram showing the concept of the wireless LAN system. As shown in FIG. 9, in the wireless LAN system, each client terminal 930 used by the user transmits and receives wireless signals to and from the access point 920 of the wireless LAN.

  Patent Document 1 describes a communication system that can perform transmission power control of a mobile station transmission module and a base station transmitter using geographic information of a mobile station using GPS. Patent Document 2 describes a mobile communication terminal apparatus that reduces power consumption by changing the detection level detection interval based on the measurement result of the distance between the terminal and the base station using GPS. ing.

JP-T-2001-526845 (page 11, FIG. 3-5) Japanese Patent Laying-Open No. 2003-163627 (paragraphs 0011-0023, FIG. 1-2)

  In the wireless LAN system shown in FIG. 9, the access point 920 and the client terminal 930 cannot automatically adjust the transmission power. Therefore, the access point 920 and the client terminal 930 may consume excessive power in order to transmit a radio signal. In addition, unauthorized access to the access point 920 cannot be detected, and communication using a wireless LAN may not be secured.

  Further, in order to distribute the load of packet processing of the wireless LAN access point 20, it is conceivable to group the client terminals 930 using two wireless channels (radio frequencies). However, if the same SSID (Service Set Identity) is used, the client terminal 930 may receive a signal of a radio channel with a higher reception strength, and thus the client terminals 930 may not be grouped well.

  In the communication system described in Patent Document 1, it is possible to automatically adjust the transmission power of the base station and the mobile station using the geographical information of the mobile station. However, in the wireless LAN system, since the access point 920 is small and light, not only the client terminal 930 is moved, but also the access point 920 itself is easily moved. Therefore, even if the communication system described in Patent Document 1 is applied to a wireless LAN, the transmission power of the access point 920 and the client terminal 930 may not be appropriately controlled only by using the geographical information of the client terminal 930. Absent.

  Moreover, the mobile communication terminal device described in Patent Document 2 only controls the detection interval of the reception level, and cannot control the transmission power of the mobile communication terminal device and the base station.

  Therefore, the present invention provides a wireless LAN system, a transmission power control method, and a transmission power control program that can appropriately control the transmission power of an access point and a client terminal and can reduce the power consumption of the access point and the client terminal. For the purpose. It is another object of the present invention to provide a location management method capable of grasping whether or not there is an unauthorized access to a wireless LAN access point.

  A wireless LAN system according to the present invention includes a terminal location calculation unit that obtains terminal location information that indicates the location of a client terminal, an access point location calculation unit that obtains access point location information that indicates the location of a wireless LAN access point, and a terminal location calculation Based on the terminal position information obtained by the means and the access point position information obtained by the access point position calculating means, the transmission power determining means for determining the transmission power value, and the transmission power value determined by the transmission power determining means And a transmission power control means for controlling the transmission power of the client terminal and the access point.

  The wireless LAN system includes a wireless LAN access point that performs wireless communication with the client terminal. In the wireless LAN system, the client terminal includes terminal location calculation means for obtaining terminal location information indicating the location of the client terminal, terminal location Terminal information transmitting means for transmitting the terminal position information obtained by the calculating means to the access point, the access point received from the client terminal and the access point position calculating means for obtaining access point position information indicating the position of the access point Based on the terminal position information and the access point position information obtained by the access point position calculating means, the transmission power determining means for determining the transmission power value, the client terminal based on the transmission power value determined by the transmission power determining means, and Send access point It may include a transmission power control means for controlling the force.

  Further, the transmission power determining means determines the transmission power value of the access point based on the terminal position information and the access point position information, and the transmission power control means is based on the transmission power value determined by the transmission power determining means. The transmission power of the access point may be changed.

  Further, the transmission power determining means determines the transmission power value of the client terminal based on the terminal position information and the access point position information, and the transmission power control means is a power including the transmission power value determined by the transmission power determining means. Value information (output power information) may be transmitted to the client terminal, and the client terminal may change the transmission power of the client terminal based on the power value information received from the transmission power control means.

  The transmission power determining means has a correspondence table in which the terminal distance indicating the distance of the client terminal from the access point is associated with the transmission power value, and the terminal distance is determined based on the terminal position information and the access point position information. The transmission power value may be determined based on the obtained correspondence table and the obtained terminal distance.

  Further, a grouping unit that divides a plurality of client terminals into groups may be provided, and the transmission power determination unit may determine a transmission power value for each group divided by the grouping unit. According to such a configuration, it is possible to distribute the packet processing load of the access point.

  Further, the grouping means sets a boundary at a predetermined distance from the access point, and sets a plurality of client terminals to a group of client terminals that are closer to the access point than the boundary, and positions that are not closer to the access point than the boundary. And may be divided into groups of client terminals.

  The wireless LAN system includes a location management information storage unit that stores location management information for managing the locations of the client terminal and the access point, and a location management information storage unit based on the terminal location information and the access point location information. Position management information updating means for updating the stored position management information may be provided. According to such a configuration, it is possible to grasp whether or not there is unauthorized access to the access point by collectively managing the location management information by the access point. Note that managing the positions of the client terminal and the access point means storing, for example, location management information including the position information of the client terminal and the access point and updating as needed.

  The wireless LAN system also includes an administrator terminal that can access the access point, and the administrator terminal displays the location of the client terminal and the access point based on the location management information stored in the location management information storage means. A screen may be displayed. According to such a configuration, an administrator who manages the access point and the client terminal can grasp whether or not there is unauthorized access to the access point.

  A transmission power control method according to the present invention is a transmission power control method for controlling the transmission power of a wireless LAN access point and a client terminal that performs wireless communication with the access point, and obtains terminal position information indicating the position of the client terminal. A step of determining access point position information indicating a position of the access point, a step of determining a transmission power value based on the determined terminal position information and access point position information, and based on the determined transmission power value And controlling the transmission power of the client terminal and the access point.

  A location management method according to the present invention is a location management method for managing the location of a wireless LAN access point and a client terminal that performs wireless communication with the access point, the location management for managing the location of the client terminal and the access point. Based on the step of storing information, the step of obtaining terminal location information indicating the location of the client terminal, the step of obtaining access point location information indicating the location of the access point, and the obtained terminal location information and access point location information, Updating the stored location management information, and an administrator terminal accessible to the access point displaying a display screen showing the location of the client terminal and the access point based on the stored location management information. It is characterized by that.

  A transmission power control program according to the present invention is a transmission power control program for controlling the transmission power of a wireless LAN access point and a client terminal that performs wireless communication with the access point, from a client terminal to a client terminal. Transmission power based on the process of receiving the terminal position information indicating the position of the access point, the process of determining the access point position information indicating the position of the access point, the terminal position information received from the client terminal and the determined access point position information A process for determining the value and a process for controlling the transmission power of the client terminal and the access point based on the determined transmission power value are executed.

  According to the present invention, the transmission power value is determined based on the location information of the access point and the client terminal. Then, the transmission power of the access point and the client terminal is controlled based on the determined transmission power value. Therefore, the transmission power of the access point and the client terminal can be appropriately controlled, and the power consumption of the access point and the client terminal can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, the application concept of the transmission power control method and the location management method according to the present invention will be described.

  FIG. 1 is an explanatory diagram showing the concept of a wireless LAN system to which a transmission power control method and a location management method according to the present invention are applied. As shown in FIG. 1, the wireless LAN system includes an access point (hereinafter referred to as a wireless LAN access point) 20 and client terminals (hereinafter referred to as wireless LAN clients) 30a and 30b. Hereinafter, the wireless LAN clients 30a and 30b are simply referred to as the wireless LAN client 30 when comprehensively expressed or when referring to any wireless LAN client. In the present embodiment, when the wireless LAN access point 20 and the wireless LAN client 30 are comprehensively expressed, they are referred to as wireless LAN devices.

  In the present embodiment, each of the wireless LAN devices 20 and 30 is equipped with a GPS device, receives a GPS signal from the GPS satellite 10 and obtains position information. The wireless LAN access point 20 determines the transmission power value of the wireless LAN devices 20 and 30 based on the position information obtained by the wireless LAN devices 20 and 30. The wireless LAN access point 20 controls the transmission power of each of the wireless LAN devices 20 and 30 based on the determined transmission power value. In the present embodiment, the position information indicating the position of the wireless LAN access point 20 required by the wireless LAN access point 20 is referred to as access point position information. Further, the position information indicating the position of the wireless LAN client 30 required by the wireless LAN client 30 is referred to as terminal position information.

  The wireless LAN access point 20 includes a database that stores location management information for managing the location of each of the wireless LAN devices 20 and 30. The wireless LAN access point 20 collectively manages the positions of the wireless LAN devices 20 and 30 by updating the position management information stored in the database as needed based on the access point position information and the terminal position information.

  In this embodiment, any user of the wireless LAN client 30 manages the wireless LAN devices 20 and 30. Hereinafter, among users of the wireless LAN client 30, a user who manages the wireless LAN devices 20 and 30 is simply referred to as an administrator. The wireless LAN client 30 used by the administrator is called an administrator terminal. In the present embodiment, the administrator operates the administrator terminal and refers to the position of each wireless LAN device 20, 30 using a browser or the like based on the position management information managed by the wireless LAN access point 20. be able to.

  In the present embodiment, the wireless LAN clients 30 can be grouped using two wireless channels (radio frequencies). In the present embodiment, the administrator can set a boundary (hereinafter referred to as a channel change line) 50 for switching a wireless channel at a predetermined distance from the wireless LAN access point 20 by operating the administrator terminal. Then, the wireless LAN clients 30 can be grouped into a wireless LAN client 30a outside the channel change line 50 and a wireless LAN client 30b inside the channel change line 50 with respect to the wireless LAN access point 20. .

  In the present embodiment, a region outside the channel change line 50 with respect to the wireless LAN access point 20 is referred to as a far channel range, and a region inside the channel change line 50 is referred to as a near channel range. A radio channel used in the far channel range is called a far channel, and a radio channel used in the near channel range is called a near channel. The wireless LAN client 30a grouped in the far channel range is called a far client, and the wireless LAN client 30b grouped in the near channel range is called a near client. In the present embodiment, it is possible to use only one wireless channel without grouping the wireless LAN clients 30.

  Next, the configuration will be described. FIG. 2 is a block diagram showing an example of the configuration of the wireless LAN system.

  As shown in FIG. 2, the wireless LAN access point 20 includes a GPS receiving unit 21, a position information database 22, a position management unit 23, output control units 24 and 25, packet processing units 26 and 27, and transceivers 28 and 29.

  Specifically, the GPS receiving unit 21 is a GPS device mounted on the wireless LAN access point 20. The GPS receiving unit 21 has a function of receiving a GPS signal from the GPS satellite 10 and obtaining access point position information based on the received GPS signal.

  Specifically, the position information database 22 is realized by a storage device of the wireless LAN access point 20. The location information database 22 stores location management information. FIG. 3 is an explanatory diagram illustrating an example of information stored in the position information database 22. As shown in FIG. 3, the location information database 22 includes, as location management information, a wireless LAN device name 301, location information 302 of the wireless LAN device, a terminal distance 303, a terminal orientation 304, use channel information 305, The update time 306 is stored in association with it.

  The wireless LAN device name 301 is the name and identification information of each wireless LAN device 20, 30. In the present embodiment, as shown in FIG. 3, the location information database 22 stores the wireless LAN device name 301 “AP” for the wireless LAN access point 20 and the wireless LAN device name 301 “CL1” for the wireless LAN client 30. , “CL2”,. The position information 302 is the latitude and longitude of each wireless LAN device 20, 30. The terminal distance 303 is the distance from the wireless LAN access point 20 of the wireless LAN client 30. The terminal orientation 304 is the orientation of the wireless LAN client 30 with respect to the wireless LAN access point 20. For example, the position information database 22 stores the terminal orientation “S” when the orientation is south.

  The used channel information 305 is information for specifying a wireless channel used by the wireless LAN client 30. In the present embodiment, the position information database 22 stores the used channel information 305 “9” when using a far channel, and stores the used channel information 305 “5” when using a nearby channel. The update time 306 is the time when the location information of the wireless LAN devices 20 and 30 is updated.

  Specifically, the location management unit 23 is realized by the CPU of the wireless LAN access point 20 that operates according to a program. When the position information 302 is updated, the position management unit 23 updates the position management information stored in the position information database 22. In the present embodiment, the location management unit 23 obtains the terminal distance and the terminal orientation based on the location information 302 of the wireless LAN access point 20 and the wireless LAN client 30, and obtains the terminal distance 303 and the terminal orientation 304 of the location information database 22. Update.

  In the present embodiment, the location information database 22 stores location management information, and the location management unit 23 updates the location management information as needed, so that the wireless LAN access point 20 manages the location of the wireless LAN devices 20 and 30. .

  Specifically, the output control units 24 and 25 are realized by a CPU and a storage device of the wireless LAN access point 20 that operates according to a program. The output control units 24 and 25 have a function of determining the transmission power value of the wireless LAN client 30 based on the terminal distance 303. For example, the output control units 24 and 25 store in advance a correspondence table indicating a correspondence relationship between the terminal distance 303 and the transmission power value of the wireless LAN client 30. Then, the output control units 24 and 25 obtain the transmission power value of the wireless LAN client 30 based on the terminal distance 303 and the correspondence table. Further, the output control units 24 and 25 have a function of outputting information including the determined transmission power value (hereinafter referred to as output power information) to the packet processing units 26 and 27.

  Further, the output control units 24 and 25 have a function of determining the transmission power values of the transceivers 28 and 29 based on the terminal distance 303. For example, the output control units 24 and 25 store in advance a correspondence table indicating a correspondence relationship between the terminal distance 303 and the transmission power values of the transceivers 28 and 29. Then, the output control units 24 and 25 obtain the transmission power values of the transceivers 28 and 29 based on the terminal distance 303 and the correspondence table. Further, the output control units 24 and 25 have a function of changing the transmission power of the transceivers 28 and 29 based on the determined transmission power value.

  In the present embodiment, the output control units 24 and 25 control the transmission power of the transceivers 28 and 29 by changing the transmission power based on the determined transmission power value. The output control units 24 and 25 control the transmission power of the wireless LAN client 30 by causing the wireless LAN client 30 to change the transmission power based on the output power information as will be described later.

  The packet processing units 26 and 27 have a function of performing packet processing of data transmitted and received by the wireless LAN access point 20. The packet processing units 26 and 27 output the output power information from the output control units 24 and 25 to the transceivers 28 and 29. Further, the packet processing units 26 and 27 store the terminal location information received by the transceivers 28 and 29 in the location information database 22 as the location information 302.

  Specifically, the transceivers 28 and 29 are wireless transmission / reception units of the wireless LAN access point 20. The transceivers 28 and 29 have a function of transmitting and receiving wireless signals to and from the wireless LAN client 30.

  In the present embodiment, the output control unit 24, the packet processing unit 26, and the transceiver 28 are used to determine the transmission power value of the remote client 30a and to perform data transmission / reception processing to the remote client 30a. Further, the output control unit 25, the packet processing unit 27, and the transceiver 29 are used to determine the transmission power value of the neighboring client 30b and to perform data transmission / reception processing to the neighboring client 30b. In this embodiment, when only one wireless channel is used without grouping the wireless LAN clients 30, only the output control unit 24, the packet processing unit 26, and the transceiver 28 are used.

  The wireless LAN client 30 is an information processing terminal such as a personal computer or a telephone that performs communication using an IP telephone service. As shown in FIG. 2, the wireless LAN client 30 includes a GPS receiving unit 31, an output control unit 32, a packet processing unit 33, and a transceiver 34. For example, a wireless LAN client 30 that is a personal computer is equipped with a wireless LAN connection device (such as a wireless LAN card) for connecting to a wireless LAN. The wireless LAN connection device includes a GPS receiving unit 31, an output control unit 32, a packet processing unit 33, and a transceiver 34.

  Specifically, the GPS receiving unit 31 is a GPS device included in the wireless LAN connection device. The GPS receiving unit 31 has a function of receiving a GPS signal from the GPS satellite 10 and obtaining terminal position information based on the received GPS signal.

  Specifically, the output control unit 32 is realized by a CPU of a wireless LAN connection device that operates according to a program. The output control unit 32 has a function of adjusting the transmission power value of the transceiver 34. In the present embodiment, the output control unit 32 changes the transmission power of the transceiver 34 based on the transmission power value included in the output power information.

  The packet processing unit 33 has a function of performing packet processing of data transmitted and received by the wireless LAN client 30. The packet processing unit 33 outputs the terminal position information obtained by the GPS receiving unit 31 to the transceiver 34. In addition, the packet processing unit 33 outputs the output power information received by the transceiver 34 to the output control unit 32.

  Specifically, the transceiver 34 is a wireless transmission / reception unit of a wireless LAN connection device. The transceiver 34 has a function of transmitting and receiving wireless signals to and from the wireless LAN access point 20.

  In FIG. 2, one remote client 30a and one neighboring client 30b are shown as the wireless LAN client 30, but the wireless LAN system includes a plurality of remote clients 30a and a plurality of neighboring clients 30b.

  In the present embodiment, the terminal position calculation means is realized by the GPS receiver 31. The access point position calculating means is realized by the GPS receiving unit 21. The transmission power determination means is realized by the output control units 24 and 25 and the position management unit 23. The transmission power control means is realized by the output control units 24 and 25, the packet processing units 26 and 27, and the transceivers 28 and 29. The terminal information transmission unit is realized by the packet processing unit 33 and the transceiver 34. The grouping means is realized by the manager terminal and the position management unit 23. The location management information storage means is realized by the location information database 22. The position information update unit is realized by the position management unit 23.

  In the present embodiment, the storage device of the wireless LAN access point 20 stores various programs for controlling the transmission power of the wireless LAN devices 20 and 30. For example, the storage device of the wireless LAN access point 20 includes a process for receiving, from a client terminal, terminal position information indicating the position of the client terminal, a process for obtaining access point position information indicating the position of the access point, and a client A process for determining a transmission power value based on the terminal position information received from the terminal and the obtained access point position information, and a process for controlling the transmission power of the client terminal and the access point based on the determined transmission power value The transmission power control program for executing is stored.

  Next, the operation will be described. FIG. 4 is a flowchart showing an example of processing for acquiring the location information of each wireless LAN device 20, 30 and updating location management information, and processing for controlling the transmission power of each wireless LAN device 20, 30.

  Each of the wireless LAN devices 20 and 30 receives GPS signals at predetermined time intervals and obtains position information (step S101). The wireless LAN client 30 transmits the obtained terminal location information to the wireless LAN access point 20 (step S102). The wireless LAN access point 20 receives terminal location information from the wireless LAN client 30 (step S103). The wireless LAN access point 20 stores the position information of each of the wireless LAN devices 20 and 30 in the position information database 22 (step S104).

  Specifically, the GPS receiving unit 21 obtains access point position information and updates the position information 302 of the wireless LAN access point 20 stored in the position information database 22. Further, the packet processing units 26 and 27 update the position information 302 of the wireless LAN client 30 stored in the position information database 22 based on the terminal position information received by the transceivers 28 and 29. Further, the location management unit 23 obtains the terminal distance and the terminal orientation based on the updated location information 302 and updates the terminal distance 303 and the terminal orientation 034 stored in the location information database 22.

  As described above, the position management information stored in the position information database 22 is updated as needed by repeatedly executing the processing from step S101 to step S104. Note that the wireless LAN access point 20 is considered to be moved less than the wireless LAN client 30. Therefore, the location information of the wireless LAN access point 20 may be updated at a longer time interval than the wireless LAN client 30.

  Next, an operation for performing transmission power control of each of the wireless LAN devices 20 and 30 will be described. The administrator terminal starts transmission power control processing of the wireless LAN devices 20 and 30 when an instruction to execute transmission power control is input by the administrator. The administrator operates the administrator terminal and inputs an instruction to select whether to group the wireless LAN clients 30 using two wireless channels or to use only one wireless channel without grouping. The administrator terminal determines whether an instruction to use two wireless channels has been input by the administrator (step S105).

  First, a case where the wireless LAN clients 30 are grouped using two wireless channels to control transmission power will be described. FIG. 5 is an explanatory diagram showing a concept when the wireless LAN clients 30 are grouped to control transmission power. As shown in FIG. 5, in this example, transmission power is controlled separately for a group of remote clients 30a existing outside the channel change line 50 and a group of neighboring clients 30b existing inside the channel change line 50. .

  If it is determined in step S105 that an instruction to use two wireless channels has been input, the administrator terminal displays a setting screen for the channel change line 50 and prompts the administrator to input a setting value for the channel change line 50. Prompt. When the setting value is input by the administrator, the administrator terminal determines the channel change line 50 according to the input setting value (step S106). In the present embodiment, a case will be described in which the administrator terminal determines the channel change line 50 at 5 meters from the wireless LAN access point 20. In addition, the administrator terminal transmits information on the determined channel change line 50 to the wireless LAN access point 20 and prompts the wireless LAN access point 20 to execute transmission power control.

  The location management unit 23 determines whether the wireless LAN client 30 is located inside the channel change line 50 based on the terminal distance 303 in the location information database 22 (step S107). If it is determined that it is not inside the channel change line 50, the location management unit 23 determines the radio channel used by the wireless LAN client 30 as the far channel (step S108). If it is determined that it is located inside the channel change line 50, the position management unit 23 determines the wireless channel used by the wireless LAN client 30 as a neighboring channel (step S109). The location management unit 23 executes the processing from step S107 to step S109 for all the wireless LAN clients 30 included in the wireless LAN system.

  For example, in the example shown in FIG. 3, since the terminal distances of the wireless LAN clients “CL1”, “CL2”, and “CL4” are smaller than the channel change line 50 “5 m”, the location management unit 23 determines the neighboring channel. Further, since the terminal distances of the wireless LAN clients “CL3” and “CL5” are larger than the channel change line 50 “5 m”, the location management unit 23 determines the far channel.

  The location management unit 23 stores the determined radio channel information in the location information database 22 as used channel information 305 (step S110). That is, the location management unit 23 groups the wireless LAN clients 30 into the remote client 30a and the nearby client 30b.

  The position management unit 23 instructs the output control units 24 and 25 to execute transmission power control. The output control units 24 and 25 execute transmission power control processing for each of the wireless LAN devices 20 and 30 in accordance with instructions from the location management unit 23 (step S111).

  In step S <b> 111, the location management unit 23 extracts the terminal distances 303 of all the remote clients 30 a from the location information database 22 and outputs them to the output control unit 24. Then, the output control unit 24 determines the transmission power value of each remote client 30a. In this case, the output control unit 24 determines the transmission power value to an optimum value that is a level at which the wireless LAN access point 20 can receive the wireless signal transmitted by the remote client 30a and is not an excessively large level. Then, the output control unit 24 outputs output power information including the determined transmission power value to the packet processing unit 26.

  Further, the output control unit 24 determines the transmission power value of the transceiver 28. In this case, based on the terminal distance 303, the output control unit 24 identifies the far client 30a farthest from the wireless LAN access point 20 (hereinafter referred to as the farthest client) among the far clients 30a. Further, the output control unit 24 determines the transmission power value to an optimum value that is a level at which the farthest client can receive the wireless signal transmitted by the wireless LAN access point 20 and is not an excessively large level. Then, the output control unit 24 changes the transmission power of the transceiver 28 based on the determined transmission power value.

  In step S <b> 111, the location management unit 23 extracts the terminal distances 303 of all the nearby clients 30 b from the location information database 22 and outputs them to the output control unit 25. Then, the output control unit 25 determines the transmission power value of each neighboring client 30b by the same processing as the output control unit 24. Then, the output control unit 25 outputs output power information including the determined transmission power value to the packet processing unit 27.

  Further, the output control unit 25 determines the transmission power value of the transceiver 29 by the same processing as the output control unit 24. Then, the output control unit 24 changes the transmission power of the transceiver 29 based on the determined transmission power value. The wireless LAN access point 20 transmits output power information to the wireless LAN client 30. The wireless LAN client 30 changes the transmission power of the transceiver 34 based on the received output power information.

  As described above, the transmission power values of the wireless LAN devices 20 and 30 can be optimized by executing the processing from step S105 to step S111. Further, since the wireless LAN clients 30 can be grouped using two wireless channels, the load of packet processing of the wireless LAN access point 20 can be distributed. Further, the wireless LAN clients 30 can be grouped into the remote client 30a and the nearby client 30b. Since the transmission power is smaller as the terminal distance is smaller, the wireless LAN access point 20 can reduce the transmission power value to the neighboring client 30b as compared with the transmission power value to the far client 30a. Therefore, the power consumption of the wireless LAN access point 20 when the wireless LAN clients 30 are grouped can be reduced.

  In step S103, the wireless LAN access point 20 may receive the terminal position information and detect the reception intensity. For example, even when the wireless LAN access point 20 is close, radio waves may not reach the wireless LAN client 30 due to an obstruction. In this case, in step S107, the location management unit 23 determines whether or not the wireless LAN client 30 is located inside the channel change line 50 and determines whether or not the reception intensity is greater than a predetermined level. to decide. And even if it is a case where it is located inside the channel change line 50, if it judges that a received electric field strength is not larger than the predetermined level determined beforehand, the position management part 23 will set the wireless channel which the wireless LAN client 30 uses. The remote channel having a large transmission power value is determined. By doing so, it is possible to appropriately control the transmission power of the wireless LAN client 30 at a position where radio waves are difficult to reach.

  In step S106, the wireless LAN access point 20 may automatically determine the channel change line 50. In this case, if it is determined in step S105 that an instruction to use two wireless channels is input, the administrator terminal transmits an instruction to execute transmission power control to the wireless LAN access point 20. Then, the location management unit 23 determines the channel change line 50 based on, for example, the terminal distance 303 stored in the location information database 22 so that the number of the far clients 30a and the neighboring clients 30b are the same.

  The wireless LAN access point 20 transmits a confirmation packet for confirming connection to each wireless LAN client 30 as needed at predetermined time intervals (step S112). When each wireless LAN client 30 receives the confirmation packet from the wireless LAN access point 20, it transmits a response packet to the wireless LAN access point 20.

  The wireless LAN access point 20 determines whether or not a packet drop has occurred between the wireless LAN access point 20 and the wireless LAN client 30 (step S113). For example, the wireless LAN access point 20 determines that a drop has not occurred when a response packet is received from the wireless LAN client 30, and determines that a drop has occurred when a response packet has not been received.

  If it is determined in step S113 that a drop has occurred, the wireless LAN access point 20 executes the process of step S111 again, and optimizes the transmission power of the wireless LAN devices 20 and 30. By doing so, the transmission power can be controlled in real time when the wireless LAN devices 20 and 30 are moved.

  Next, a case where transmission power is controlled using only one radio channel will be described. FIG. 6 is an explanatory diagram showing a concept when transmission power is controlled using only one radio channel. As shown in FIG. 6, in this example, transmission power is controlled without grouping the wireless LAN clients 30.

  If it is determined in step S105 that an instruction to use only one wireless channel is input, the administrator terminal transmits an instruction to execute transmission power control to the wireless LAN access point 20 without executing step S106.

  The location management unit 23 stores the radio channel information in the location information database 22 (step S110). In this case, the location management unit 23 stores the channel information 305 “9” for all the wireless LAN clients 30.

  The position management unit 23 instructs the output control unit 24 to execute transmission power control. In this case, the position management unit 23 instructs only the output control unit 24 to execute transmission power control. The output control unit 24 executes transmission power control processing for each of the wireless LAN devices 20 and 30 in accordance with the instruction from the location management unit 23 (step S111). Further, the wireless LAN client 30 changes the transmission power based on the output power information from the wireless LAN access point 20. Note that the processing after step S112 is the same as the case where grouping is performed using two radio channels.

  Next, an operation in the case of performing location management of each wireless LAN device 20 and 30 will be described. FIG. 7 is an explanatory diagram showing an application concept of location management of the wireless LAN devices 20 and 30. In this example, the location management of the wireless LAN devices 20 and 30 is performed to monitor unauthorized access pretending to be a user with access authority to the network. Hereinafter, the terminal 40 that impersonates a user having access authority to the network is referred to as an unauthorized client. In the present embodiment, the wireless LAN access point 20 collectively manages the location of each of the wireless LAN devices 20 and 30 so that the administrator grasps unauthorized access from the unauthorized client 40.

  The administrator operates the administrator terminal to input instructions for displaying the positions of the wireless LAN devices 20 and 30. When an instruction is input by the administrator, the administrator terminal transmits a request for transmitting location management information to the wireless LAN access point 20. Then, the location management unit 23 of the wireless LAN access point 20 extracts the location management information of each of the wireless LAN devices 20 and 30 from the location information database 22 and transmits the extracted location management information to the administrator terminal.

  The administrator terminal displays a display screen for the positions of the wireless LAN devices 20 and 30 based on the received position management information. For example, the administrator terminal displays a display screen showing the positions of the wireless LAN devices 20 and 30 using a browser installed in the administrator terminal.

  FIG. 8 is an explanatory diagram illustrating an example of a display screen on which the positions of the wireless LAN devices 20 and 30 are displayed using a browser. As shown in FIG. 8, the administrator terminal displays a display screen illustrating the positions of the wireless LAN access point 20, the remote client 30a, and the nearby client 30b. For example, as shown in FIG. 8, the administrator terminal displays the position of the wireless LAN access point 20 at the center of the screen. Further, the administrator terminal displays the position of each wireless LAN client 30 based on the terminal distance 303 and the terminal direction 304 included in the position management information.

  As shown in FIG. 8, when the display of the wireless LAN client 30 is clicked by the user, the administrator terminal displays the SSID of the wireless LAN client 30, the access point name of the connection destination, the IP of the wireless LAN client 30. Displays the address, transmission power value (output power), and the wireless channel in use. For example, the wireless LAN access point 20 stores the SSID, IP address, and transmission power value of each wireless LAN client 30 in a database, and transmits these pieces of information together with location management information to the administrator terminal. Then, the administrator terminal displays the SSID, IP address, and transmission power value received from the wireless LAN access point 20. Further, the administrator terminal displays the used channel information 305 included in the location management information. Note that the administrator terminal may display the user name and account of the user of the wireless LAN client 30.

  The administrator visually confirms whether there is no access from an unauthorized client 40 other than the wireless LAN client 30 managed by the administrator by confirming the position of each wireless LAN client 30 on the display screen of the browser. can do. Further, it is possible to confirm whether or not there is an access from the unauthorized client 40 by confirming the ID information of the wireless LAN client 30 being accessed.

  In step S102 of FIG. 4, the wireless LAN client 30 may transmit the position information encrypted and compressed. By doing so, it is possible to prevent the unauthorized client 40 from improperly transmitting the location information to the wireless LAN access point 20 and impersonating the wireless LAN client 30, and to improve the reliability of location management.

  As described above, according to the present embodiment, the wireless LAN access point 20 determines the transmission power value of each wireless LAN device 20, 30 based on the position information of each wireless LAN device 20, 30. The wireless LAN access point 20 controls the transmission power of each of the wireless LAN devices 20 and 30 based on the determined transmission power value. Therefore, in the wireless LAN system, the transmission power of the access point and the client terminal can be appropriately controlled, and the power consumption of the access point and the client terminal can be reduced.

  Further, according to the present embodiment, the wireless LAN access point 20 collectively manages the location management information, and the administrator can confirm the location of each of the wireless LAN devices 20 and 30 using the administrator terminal. Therefore, the administrator can grasp whether or not there is an unauthorized access to the access point of the wireless LAN.

  Further, according to the present embodiment, the wireless LAN clients 30 can be grouped using two wireless channels. Accordingly, the packet processing load of the wireless LAN access point 20 can be distributed.

  The present invention can be applied to the use of controlling the transmission power of each client terminal and access point in a wireless LAN system. In particular, even when the access point is small and lightweight and easily moved, the transmission power of the client terminal and the access point can be appropriately controlled based on the position information. Further, the present invention can be applied to location management of each client terminal and access point in a wireless LAN system.

It is explanatory drawing which shows the concept of the wireless LAN system to which the transmission power control method and position management method by this invention are applied. It is a block diagram which shows an example of a structure of a wireless LAN system. It is explanatory drawing which shows the example of the information which the position information database 22 memorize | stores. 5 is a flowchart showing an example of processing for acquiring location information of each wireless LAN device 20, 30 and updating location management information, and processing for controlling transmission power of each wireless LAN device 20, 30. It is explanatory drawing which shows the concept in case the wireless LAN client 30 is grouped and transmission power is controlled. It is explanatory drawing which shows the concept in case transmission power is controlled using only one radio channel. 2 is an explanatory diagram showing an application concept of location management of each wireless LAN device 20, 30. FIG. It is explanatory drawing which shows the example of the display screen which displayed the position of the wireless LAN apparatuses 20 and 30 using the browser. It is explanatory drawing which shows the concept of the conventional wireless LAN system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 GPS satellite 20 Wireless LAN access point 21 GPS receiving part 22 Position information database 23 Position management part 24, 25 Output control part 26, 27 Packet processing part 28, 29 Transceiver 30a, 30b Wireless LAN client 31 GPS receiving part 32 Output control part 33 Packet processing unit 34 Transceiver

Claims (12)

Terminal position calculating means for obtaining terminal position information indicating the position of the client terminal;
Access point position calculating means for obtaining access point position information indicating the position of the access point of the wireless LAN;
Transmission power determining means for determining a transmission power value based on the terminal position information obtained by the terminal position calculating means and the access point position information obtained by the access point position calculating means;
A wireless LAN system comprising: a transmission power control unit that controls transmission power of the client terminal and the access point based on a transmission power value determined by the transmission power determination unit. In a wireless LAN system equipped with a wireless LAN access point that performs wireless communication with a client terminal,
The client terminal is
Terminal position calculating means for obtaining terminal position information indicating the position of the client terminal;
Terminal information transmitting means for transmitting the terminal position information obtained by the terminal position calculating means to the access point,
The access point is
Access point position calculating means for obtaining access point position information indicating the position of the access point;
Transmission power determining means for determining a transmission power value based on the terminal position information received from the client terminal and the access point position information obtained by the access point position calculating means;
A wireless LAN system comprising: transmission power control means for controlling transmission power of the client terminal and the access point based on a transmission power value determined by the transmission power determination means. The transmission power determining means determines the transmission power value of the access point based on the terminal position information and the access point position information,
The wireless LAN system according to claim 1 or 2, wherein the transmission power control means changes the transmission power of the access point based on the transmission power value determined by the transmission power determination means. The transmission power determining means determines the transmission power value of the client terminal based on the terminal position information and the access point position information,
The transmission power control means transmits power value information including the transmission power value determined by the transmission power determination means to the client terminal,
The wireless LAN system according to any one of claims 1 to 3, wherein the client terminal changes transmission power of the client terminal based on power value information received from the transmission power control means. The transmission power determination means is
A correspondence table in which a terminal distance indicating a distance of the client terminal from the access point is associated with a transmission power value;
Find the terminal distance based on the terminal location information and access point location information,
The wireless LAN system according to any one of claims 1 to 4, wherein a transmission power value is determined based on the correspondence table and the obtained terminal distance. A grouping means for dividing a plurality of client terminals into groups,
The wireless LAN system according to any one of claims 1 to 5, wherein the transmission power determination unit determines a transmission power value for each group divided by the grouping unit. Grouping means are
Set a boundary at a predetermined distance from the access point,
The wireless client according to claim 6, wherein the plurality of client terminals are divided into a group of client terminals located closer to the access point than the boundary and a group of client terminals located closer to the access point than the boundary. LAN system. Location management information storage means for storing location management information for managing the location of the client terminal and access point;
The position management information update means for updating the position management information stored in the position management information storage means on the basis of the terminal position information and the access point position information. The wireless LAN system described in 1. It has an administrator terminal that can access the access point,
The wireless LAN system according to claim 8, wherein the manager terminal displays a display screen showing the positions of the client terminal and the access point based on the location management information stored in the location management information storage means. A transmission power control method for controlling transmission power of a wireless LAN access point and a client terminal that performs wireless communication with the access point,
Obtaining terminal location information indicating the location of the client terminal;
Obtaining access point location information indicating the location of the access point;
Determining a transmission power value based on the obtained terminal location information and access point location information;
And a step of controlling transmission power of the client terminal and the access point based on the determined transmission power value. A location management method for managing a location of a wireless LAN access point and a client terminal that performs wireless communication with the access point,
Storing location management information for managing the location of the client terminal and the access point;
Obtaining terminal location information indicating the location of the client terminal;
Obtaining access point location information indicating the location of the access point;
Updating the stored location management information based on the obtained terminal location information and the access point location information;
An administrator terminal that can access the access point includes a step of displaying a display screen showing the positions of the client terminal and the access point based on the stored position management information. Method. A transmission power control program for controlling transmission power of a wireless LAN access point and a client terminal that performs wireless communication with the access point,
On the computer,
Processing for receiving terminal position information indicating the position of the client terminal from the client terminal;
Processing for obtaining access point location information indicating the location of the access point;
Processing for determining a transmission power value based on the terminal location information received from the client terminal and the obtained access point location information;
A transmission power control program for executing processing for controlling transmission power of the client terminal and the access point based on the determined transmission power value.

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