JP2008118419A - Repeater, radio communication terminal, communication system, and communication method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure security in radio communication while suppressing the burden of an operator. <P>SOLUTION: This radio communication terminal requesting authentication transmits authentication request information 212 several times while changing the strength of a communication radio wave. Each time this repeater (access point) receives the authentication request information 212, a measuring part 500 measures the strength of the communication radio wave to generate measurement information 511. A determination part 501 compares the strength of the communication radio wave with threshold information 512, determines strength larger than the threshold information 512 as "1" and strength smaller than the threshold information 512 as "0" to generate determination information 513. An authentication part 503 compares the determination information 513 with authentication information 514 to thereby authenticate the radio communication terminal requesting authentication. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technique for safely performing wireless communication. More specifically, the present invention relates to a technique for authenticating a communication terminal that performs wireless communication in a repeater.

  In a communication system using wireless communication, it is necessary to limit wireless communication terminals that permit access in order to prevent unauthorized access from the outside. In order to solve this problem, a technique is known in which an operator inputs a WEP key to a wireless communication terminal, and the content of communication is encrypted with the WEP key to perform wireless communication.

  However, since information such as a WEP key is used every time wireless communication is performed, it is required to be complicated information. On the other hand, the task of accurately inputting complicated information for the operator is heavy. In particular, when an additional wireless communication terminal is added, a general user must input such information as an operator, which is a further problem.

  For example, Patent Document 1 proposes a technique in which authentication information is transmitted from a wireless communication terminal and a WEP key is transmitted from a repeater only when the authentication information can be received with a communication radio wave equal to or greater than a certain threshold. . In other words, a wireless communication terminal that transmits authentication information from a neighborhood with a relatively good radio wave condition recognizes that it is a legitimate wireless communication terminal, thereby reducing the burden on the operator by omitting complicated information input.

Japanese Patent Laid-Open No. 2006-100757

  However, the technique described in Patent Document 1 has a problem that if the authentication information can be received even once, it is recognized as a legitimate wireless communication terminal. That is, when the wireless communication is not established, increasing the strength of the communication radio wave to be transmitted is a general solution on the wireless communication terminal side. There was a problem that was too low.

  The present invention has been made in view of the above problems, and an object of the present invention is to ensure security in wireless communication while suppressing the burden on an operator.

  In order to solve the above problems, the invention of claim 1 is a repeater that performs wireless communication with one or more wireless communication terminals, and includes a wireless communication unit that transmits and receives information using communication radio waves, and a plurality of bits. A storage unit that stores the authentication information, and a measurement unit that measures the strength of a communication radio wave when the authentication request information is received each time the wireless communication unit receives the authentication request information from a wireless communication terminal And comparing the strength of the communication radio wave when the one authentication request information is received with a threshold based on the measurement result of the measurement unit, and determining the state of the communication radio wave when the one authentication request information is received A determination unit that determines that the wireless communication terminal is 1 or 0; and an authentication unit that authenticates the wireless communication terminal based on a determination result of the determination unit and authentication information stored in the storage unit. .

  The invention according to claim 2 is the repeater according to the invention of claim 1, wherein the authentication information is information including at least one 1-state bit and at least one 0-state bit. The determination unit determines the threshold based on a measurement result of the measurement unit.

  According to a third aspect of the present invention, there is provided a computer-readable program, and the execution of the program by the computer transmits and receives information by a communication step and a storage step of storing authentication information consisting of a plurality of bits. A wireless communication step, and in the wireless communication step, each time one authentication request information is received from a wireless communication terminal, a measurement step of measuring the strength of a communication radio wave when the one authentication request information is received, and Based on the measurement result in the measurement step, the communication radio wave intensity when the one authentication request information is received is compared with a threshold value, and the state of the communication radio wave when the one authentication request information is received is 1 or 0. The wireless communication based on the determination step of determining that it is, the determination result in the determination step and the authentication information stored in the storage step. Characterized in that to execute the authentication process for authenticating the terminal.

  According to a fourth aspect of the present invention, there is provided a wireless communication terminal that performs wireless communication with a repeater, an operation unit that receives a passcode, a storage unit that stores the passcode received by the operation unit, and a communication Based on a wireless communication unit that transmits information to the repeater by radio waves and a passcode stored in the storage unit, the number of times of authentication request information to be transmitted to the repeater is determined, and one authentication request A communication control unit that controls the wireless communication unit by determining the strength of communication radio waves when transmitting information for each piece of the authentication request information.

  The invention according to claim 5 is the wireless communication terminal according to the invention of claim 4, wherein the communication control unit determines the number of transmissions according to the number of bits of the passcode received by the operation unit. It is characterized by that.

  The invention of claim 6 is a computer-readable program, and the execution of the program by the computer stores in the computer an input step for receiving a passcode and a passcode received in the input step. A step of determining the number of times of transmission of the authentication request information based on the pass code stored in the storage step, and the strength of the communication radio wave when transmitting the one piece of authentication request information. A strength determination step for determining each authentication request information, and a wireless communication step for transmitting the authentication request information to the repeater by the number of transmissions determined in the number determination step with the communication radio wave determined in the strength determination step. Are executed.

  The invention of claim 7 is a communication system in which one or more wireless communication terminals perform wireless communication with a repeater, wherein the repeater transmits and receives information by communication radio waves, and a plurality of wireless communication units. Each time the wireless communication unit receives a piece of authentication request information from a wireless communication terminal, the storage unit that stores the authentication information consisting of bits measures the strength of the communication radio wave when the piece of authentication request information is received. Based on the measurement result of the measurement unit and the measurement unit, the communication radio wave intensity when the one authentication request information is received is compared with a threshold value, and the communication radio wave when the one authentication request information is received is compared. A determination unit that determines that the state is 1 or 0, and an authentication unit that authenticates the one wireless communication terminal based on a determination result of the determination unit and authentication information stored in the storage unit, The wireless communication terminal has a passcode Based on the operation unit that is received, the storage unit that stores the passcode received by the operation unit, the wireless communication unit that transmits information to the repeater by communication radio waves, and the passcode stored in the storage unit, In addition to determining the number of times authentication request information to be transmitted to the repeater is transmitted, the wireless communication unit is controlled by determining the strength of a communication radio wave for transmitting the one authentication request information for each authentication request information. And a communication control unit.

  The invention according to claim 8 is the communication system according to the invention of claim 7, wherein the communication control unit includes a transmission number in the authentication request information, and the measurement unit includes a transmission number included in the authentication request information. And the strength of the communication radio wave when the authentication request information is received.

  The invention of claim 9 is a communication method in which one or more wireless communication terminals perform wireless communication with a repeater, wherein the first storage step stores authentication information consisting of a plurality of bits in the repeater; An authentication process based on an input step of receiving a passcode in the wireless communication terminal, a second storage step of storing the passcode received in the input step in the wireless communication terminal, and a passcode stored in the second storage step The number-of-times determining step for determining the number of times of transmission of request information, the strength determining step for determining the strength of communication radio waves when transmitting one piece of authentication request information for each piece of one piece of authentication request information, and the step of determining the strength A wireless transmission step of transmitting authentication request information from the wireless communication terminal by the number of transmissions determined in the number of times determination step with a communication radio wave of a determined strength; A radio reception step for receiving the authentication request information transmitted in step 1 and a communication radio wave when the one authentication request information is received each time one authentication request information is received from the wireless communication terminal in the radio reception step. A measurement step of measuring the strength of the communication, and based on a measurement result in the measurement step, the strength of the communication radio wave when the one authentication request information is received and a threshold value are compared, and the one authentication request information is received A determination step of determining that the state of the communication radio wave is 1 or 0, an authentication step of authenticating the wireless communication terminal based on the determination result in the determination step and the authentication information stored in the first storage step; It is characterized by providing.

  According to the first to third and seventh to ninth aspects of the invention, each time one piece of authentication request information is received from the wireless communication terminal, the strength of the communication radio wave when the one piece of authentication request information is received is measured. It is possible to easily and safely authenticate the wireless communication terminal by determining that the state of the communication radio wave when receiving the authentication request information is 1 or 0 and authenticating the authentication radio wave by comparing with the authentication information. it can.

  In the invention according to claim 2, the authentication information is information including at least one 1-state bit and at least one 0-state bit, and the determination unit is based on the measurement result of the measurement unit, By determining the threshold value, the threshold value can be determined according to the communication state when authentication is performed.

  In the inventions according to claims 4 to 6, the number of times of authentication request information to be transmitted to the repeater is determined based on the pass code, and the strength of the communication radio wave when transmitting one authentication request information is set to one. By determining each authentication request information, security can be improved without requiring a complicated passcode.

  In the invention according to claim 8, the communication control unit includes the transmission number in the authentication request information, and the measurement unit includes the transmission number included in the authentication request information, and the strength of the communication radio wave when the authentication request information is received. , It is possible to easily determine whether or not the authentication request information has been received for each transmitted authentication request information. Therefore, the authentication accuracy is improved.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings.

<1. Embodiment>
FIG. 1 is a diagram showing a door phone system 1 which is a communication system according to the present invention. The door phone system 1 includes an indoor cordless handset 2, an outdoor cordless handset 3, an outdoor camera 4, and a main unit 5. The door phone system 1 has a function of notifying the home (resident) of the presence or absence of a visitor and a function of providing an extension call between the indoor cordless handsets 2.

  In general, information transmitted and received by the door phone system 1 is of a nature that should be limited to the householder, and in particular in wireless communication, it is necessary to prevent unauthorized access from the outside. In addition, the wireless communication terminals (indoor unit 2 and outdoor camera 4) used in the door phone system 1 may be added after installation, and in that case, registration (activation) of the wireless communication terminal added by a householder is usually performed. ) Is executed.

  Note that the communication system according to the present invention is not limited to the door phone system 1 and can be applied to a general system using a wireless LAN, for example.

  FIG. 2 is a block diagram showing the configuration of the indoor cordless handset 2. The indoor cordless handset 2 that is a wireless communication terminal in the present invention includes a CPU 20, a storage device 21, an operation unit 22, a display unit 23, a speaker 24, a microphone 25, and a wireless communication unit 27.

  The CPU 20 operates in accordance with the program 210 stored in the storage device 21 to calculate various data and generate control signals. As shown in FIG. 2, CPU20 is connected with each structure of the indoor subunit | mobile_unit 2 by bus wiring, and controls these structures with the produced | generated control signal. Details of operations and functions of the CPU 20 will be described later.

  The storage device 21 includes various ROMs and RAMs, and stores programs 210 and various data.

  The operation unit 22 includes a plurality of buttons. The operator can input necessary instruction information to the indoor cordless handset 2 (door phone system 1) by operating the operation unit 22. The instruction information input by the operator includes response information for answering a call, a pass code, and the like.

  The display unit 23 includes a liquid crystal display, LEDs, and the like, and has a function of displaying various information and notifying the operator of various states. For example, the display unit 23 displays information indicating whether or not the authentication by the main unit 5 is successful.

  The speaker 24 is a general audio reproduction device and has a function of reproducing audio based on an electric signal. As voice included in the voice information reproduced by the speaker 24, voice transmitted from the outdoor cordless handset 3 or other indoor cordless handset 2 through the main unit 5 (voice in an external line / extension call), or the storage device 21 There is a pre-stored ring tone.

  The microphone 25 has a function of converting sound around the indoor cordless handset 2 into an electrical signal. The microphone 25 is mainly used to convert the voice of an operator who uses the indoor cordless handset 2 into voice information.

  The wireless communication unit 27 has a function of connecting the indoor cordless handset 2 and the main unit 5 in a state where information can be exchanged by wireless communication. Specifically, a transmission antenna, a reception antenna, and the like for realizing wireless communication are applicable.

  FIG. 3 is a diagram showing functional blocks of the indoor unit 2 together with the information flow. The communication control unit 200 and the timer 201 shown in FIG. 3 are functional blocks realized mainly by the CPU 20 operating according to the program 210.

  The communication control unit 200 refers to the passcode 211 received by the operation unit 22 and determines the number N of times for transmitting the authentication request information 212 based on the referenced passcode 211. Each time one piece of authentication request information 212 is transmitted, the strength of the communication radio wave that transmits the authentication request information 212 is determined (that is, the strength of communication radio waves for N times is determined).

  Further, the communication control unit 200 includes in the authentication request information 212 a transmission number (a number from 1 to N) indicating what number of transmission the authentication request information 212 relates to.

  Further, the communication control unit 200 includes the time transmitted from the timer 201 in the authentication request information 212. As a result, the authentication request information 212 transmitted from the indoor child device 2 includes the time transmitted from the indoor child device 2.

  The timer 201 measures the time and transmits the result to the communication control unit 200.

  FIG. 4 is a diagram illustrating the structure of the authentication request information 212. As shown in FIG. 4, the authentication request information 212 includes a command identifier 213, a manufacturer identification code 214, time information 215, and a transmission number 216.

  The command identifier 213 is information for identifying that the information is the authentication request information 212, and is mainly information that is referred to by the main unit 5 that receives the authentication request information 212. The command identifier 213 is previously determined as fixed information in the door phone system 1.

  The manufacturer identification code 214 is information for identifying the manufacturer of the door phone system 1, but is not an essential information item, and may be information such as a product number, for example. In this way, by including arbitrary information in the authentication request information 212, the authentication accuracy can be further improved.

  As described above, the time information 215 and the transmission number 216 are information included by the communication control unit 200 before transmission, and are different information (contents) for each authentication request information 212 transmitted N times.

  Returning to FIG. 1, the outdoor unit 3 includes an operation button (not shown), and is mainly operated by a visitor who has visited the residence. When the operation button is operated by the visitor, the outdoor unit 3 generates visit information indicating that the operation button has been operated and transmits it to the main unit 5. That is, by receiving visit information from the outdoor unit 3, the main unit 5 detects that there is a visitor.

  As shown in FIG. 1, the outdoor unit 3 is connected to the main unit 5 via a cable, and performs wired communication with the main unit 5. Thus, the door phone system 1 may include a wired communication terminal that performs wired communication, like the outdoor slave unit 3.

  The outdoor unit 3 includes a speaker, a microphone, and a camera (not shown), and can make a voice call with the indoor unit 2 connected to the line by the main unit 5. It is also possible to send image information to the destination. That is, the voice uttered by the visitor is converted into voice information by the microphone and transmitted, and the visitor is imaged by the camera and the image information is transmitted. Moreover, the audio | voice information received from the indoor subunit | mobile_unit 2 is reproduced | regenerated with a speaker.

  FIG. 5 is a block diagram showing the configuration of the outdoor camera 4. As with the indoor unit 2, the outdoor camera 4 that is a wireless communication terminal in the present invention includes a CPU 40, a storage device 41, an operation unit 42, a display unit 43, an imaging unit 44, and a wireless communication unit 47.

  The CPU 40 operates in accordance with a program 410 stored in the storage device 41, thereby calculating various data and generating control signals. As shown in FIG. 4, the CPU 40 is connected to each component of the outdoor camera 4 by bus wiring, and controls these components by the generated control signal. Note that the CPU 40 implements the same functional blocks as the communication control unit 200 and the timer 201 by operating according to the program 410.

  The storage device 41 includes various ROMs and RAMs, and stores a program 410 and various data (passcode 211 and authentication request information 212).

  The operation unit 42 includes a plurality of buttons. The operator can input necessary instruction information to the outdoor camera 4 by operating the operation unit 42. In particular, in the outdoor camera 4 in the present embodiment, a pass code is input from the operation unit 42.

  The display unit 43 is composed of LEDs and the like, and has a function of displaying various information by blinking them and notifying the operator of various states. For example, the display unit 43 displays information indicating whether or not the authentication by the main unit 5 has been successful.

  The imaging unit 44 has a function as a general digital camera, and acquires image information by imaging a predetermined imaging area. The imaging unit 44 in the present embodiment captures a moving image, but may of course be a still image.

  The wireless communication unit 47 has a function of connecting the outdoor camera 4 and the main unit 5 in a state where information can be exchanged by wireless communication. Specifically, a transmission antenna, a reception antenna, and the like for realizing wireless communication are applicable.

  With such a configuration, the outdoor camera 4 is connected to the main unit 5 by the wireless communication unit 47, and the imaging unit 44 performs imaging based on a control signal from the main unit 5. Further, the image information acquired by imaging is transmitted to the main unit 5 by the wireless communication unit 47.

  FIG. 6 is a block diagram showing the configuration of the main unit 5. The main unit 5 includes a CPU 50, a storage device 51, an operation unit 52, a display unit 53, a wireless communication unit 57, and a wired communication unit 58, and has a function as a router that relays communication between devices included in the door phone system 1. .

  As described above, in the door phone system 1, the indoor unit 2 and the outdoor camera 4 are configured as wireless communication terminals that perform wireless communication. Accordingly, when the indoor cordless handset 2 and the outdoor camera 4 perform communication (wireless communication), the main unit 5 functions as an access point (relay device).

  The CPU 50 operates in accordance with a program 510 stored in the storage device 51, thereby calculating various data and generating control signals. As shown in FIG. 6, the CPU 50 is connected to each component of the main unit 5 by bus wiring, and controls these components by the generated control signal. The operation and function of the CPU 50 will be described later.

  The storage device 51 includes various ROMs, RAMs, and the like, and stores a program 510 and various data (parameter information and the like).

  The operation unit 52 includes a plurality of buttons. The operator of the main unit 5 can input necessary instruction information to the main unit 5 (door phone system 1) by operating the operation unit 52.

  The display unit 53 includes LEDs, lamps, and the like, and has a function of notifying the operator of various states according to the blinking state. The display unit 53 may include a liquid crystal display that displays various types of information as images.

  The wireless communication unit 57 has a function of connecting a configuration for wireless data communication (in the present embodiment, the indoor slave unit 2 and the outdoor camera 4) and the main unit 5 in a state where data communication is possible. Specifically, it includes a transmitting antenna and a receiving antenna for realizing wireless communication.

  The wired communication unit 58 has a function of connecting a configuration (outdoor slave unit 3) that performs wired data communication and the main unit 5 in a state where data communication is possible. Specifically, the terminal etc. which connect the various cables for communication correspond.

  FIG. 7 is a diagram showing the functional blocks of the main unit 5 together with the flow of information. The measurement unit 500, the determination unit 501, the timer 502, and the authentication unit 503 illustrated in FIG. 7 are functional blocks realized mainly by the CPU 50 operating according to the program 510.

  Measurement unit 500 measures the strength of communication radio waves when wireless communication unit 57 receives information. Then, based on whether or not the command identifier 213 is included in the received information, it is determined whether or not the information is the authentication request information 212. Further, when the received information is the authentication request information 212, the strength of the communication radio wave when the authentication request information 212 is received is stored in the storage device 51 as the measurement information 511.

  That is, the measurement unit 500 has a function of measuring the strength (reception strength) of communication radio waves used for transmitting one authentication request information 212 and generating measurement information 511.

  Whether determination unit 501 has received at least one or more authentication request information 212 received from one wireless communication terminal (indoor child device 2 or outdoor camera 4) by referring to authentication request information 212 and timer 502 Detect whether or not.

  In the door phone system 1 according to the present embodiment, for example, when a certain indoor unit 2 is registered in the main unit 5, the authentication request information 212 is transmitted from the indoor unit 2 a plurality of times (N times). Therefore, when performing authentication, the main unit 5 needs to detect whether or not all the authentication request information 212 (N authentication request information 212) transmitted from the terminal requesting authentication has been received. A specific operation for detecting reception completion will be described later.

  In addition, the determination unit 501 generates threshold information 512 with reference to the measurement information 511 in a state where reception is completed. The determination unit 501 in the present embodiment obtains the maximum value V of the communication radio wave intensity recorded in the measurement information 511, sets the threshold value Q to 3 / 4V, and generates threshold value information 512.

  Further, the determination unit 501 refers to the measurement information 511 and compares the intensity of the communication radio wave when the one authentication request information 212 is received with the threshold information 512. Then, if the intensity of the communication radio wave compared is greater than the threshold value Q, the state of the communication radio wave is determined as “1”, and otherwise, the state of the communication radio wave is determined as “0”. Based on the determination result, determination information 513 is generated. That is, the determination information 513 is generated every time reception of a series of authentication request information 212 is completed.

  The timer 502 measures the time and transmits the result to the determination unit 501.

  The authentication unit 503 compares the determination information 513 and the authentication information 514 and determines the wireless communication terminals (the indoor unit 2 and the outdoor camera 4) that have transmitted the authentication request information 212 based on whether or not they match. Certify.

  The above is description of the structure and function of the door phone system 1 in this Embodiment. Next, the operation of the door phone system 1 will be described.

  In the door phone system 1, since information on wireless communication is not known to others, information is transmitted between the main unit 5 as an access point and a regular wireless communication terminal (the indoor handset 2 and the outdoor camera 4 used by a householder). Send and receive encrypted. Information (WEP key) necessary for encryption (decryption) is transmitted from the main unit 5 to a wireless communication terminal authenticated as a legitimate wireless communication terminal. Therefore, the indoor cordless handset 2 and the outdoor camera 4 cannot be used in the door phone system 1 unless authenticated by the main unit 5 in advance.

  8 and 9 are flowcharts showing the operation of the indoor cordless handset 2. 8 and 9 mainly show processing in which the indoor unit 2 requests the main unit 5 for authentication.

  In the present embodiment, the authentication information 514 stored in advance in the main unit 5 is multi-bit information set individually for each main unit 5. Further, the authentication information 514 in the present embodiment is arbitrary information in which the state of at least one bit is “1” and the state of at least one bit is “0”. For example, “0” or “00” that does not include the state of “1” in the binary representation, “1” or “11” that does not include the state of “0”, “0” or “1” that is not a plurality of bits, etc. Although it cannot be set as the authentication information 514, it may be “01”. In the door phone system 1, “01” and “001” in the authentication information 514 are clearly distinguished.

  It is assumed that a legitimate operator who authenticates the indoor unit 2 is separately informed using the authentication information 514 as a passcode. For example, the pass code is described in a product warranty or manual, and the operator can know the pass code by looking at it.

  In the following, a case where the authentication information 514 is “0101” in binary notation will be described as an example, but the content of the authentication information 514 is not limited to this.

  When the power of the indoor child device 2 is turned on, the indoor child device 2 stands by until a passcode is input by the operator (step S11).

  In order to make the indoor cordless handset 2 usable in the door phone system 1, the operator operates the operation unit 22 of the indoor cordless handset 2 and inputs a previously known passcode. It is assumed that the operator performs authentication work in the vicinity of the main unit 5 before installing the indoor cordless handset 2 and the outdoor camera 4 (before installing in each room or outdoors).

  When the operation unit 22 is operated and a pass code is input, the indoor unit 2 determines Yes in step S <b> 11 and stores the input pass code in the storage device 21 as the pass code 211.

  Next, the communication control unit 200 acquires the passcode 211 from the storage device 21 (step S12), and determines the number N of times to transmit the authentication request information 212 based on the acquired passcode 211 (step S13). Here, the communication control unit 200 sets the digit number of the most significant bit of the passcode 211 to “N”. It does not matter whether the content of the most significant bit is “0” or “1”. For example, the number N may be determined by simply counting the number of “0” and “1” input as the passcode.

  Next, the communication control part 200 determines the intensity | strength of the communication electromagnetic wave for transmitting the one authentication request information 212 for every time based on the passcode 211 acquired at step S12 (step S14).

  Specifically, for each bit of the passcode 211, it is determined whether the content is “1” or “0”. When the content is “1”, the communication radio wave intensity is set to “100”, “ When it is “0”, it is determined as “50”. That is, if the pass code 211 is “0101”, the strength of the communication radio wave to be transmitted is determined as “100, 50, 100, 50” (transmitted from the lower bits).

  Note that “100” in the example shown here means 100% of the maximum intensity that the wireless communication unit 27 can transmit, and “50” means 50%. However, it is not limited to such a value.

  When the intensity of the communication radio wave is determined, the communication control unit 200 sets the counter to 1 (step S15). That is, the counter is reset to 1. The counter referred to here is information for counting the number of times the authentication request information 212 is transmitted.

  Next, the communication control unit 200 includes the value indicated in the counter as the transmission number 216 in the authentication request information 212 (step S21), refers to the timer 201, and authenticates the time at that time as the time information 215. It is included in the request information 212 (step S22). As a result, authentication request information 212 to be transmitted next is prepared.

  Since the authentication request information 212 in the present embodiment is information transmitted before authentication, it can be said that there is a high possibility that the authentication request information 212 will be decrypted compared to subsequent communication. In addition, there is a problem that if information with similar contents is transmitted many times, the possibility of further decryption increases. However, since the time information 215 is included in the authentication request information 212 in this way, the information to be communicated is scrambled, so that the transmission content can be decrypted by a third party who intercepts the communication for authentication. Can be suppressed.

  When the authentication request information 212 is prepared, the communication control unit 200 transmits the communication radio wave intensity corresponding to the counter value at that time to the wireless communication unit 27. Thereby, the wireless communication part 27 sets the intensity | strength of the communication electromagnetic wave at the time of transmitting the authentication request information 212 (step S23).

  Note that the communication control unit 200 in the present embodiment controls the wireless communication unit 27 to transmit the corresponding authentication request information 212 in order from the lower bit of the passcode 211. That is, the transmission number 216 matches the bit number (digit number) of the input passcode.

  If the passcode is normally input in the example shown here, the communication control unit 200 transmits “100” as the communication radio wave intensity to the wireless communication unit 27 in the first and third times, and the second and fourth times. At the second time, “50” is transmitted to the wireless communication unit 27 as the strength of the communication radio wave.

  When the strength of the communication radio wave is set based on the numerical value transmitted from the communication control unit 200, the wireless communication unit 27 acquires the one authentication request information 212 from the storage device 21, and uses the communication radio wave with the set strength, It transmits toward the unit 5 (step S24). The authentication request information 212 transmitted at this time is received by the main unit 5. The operation of the main unit 5 that has received the authentication request information 212 will be described later.

  Next, the communication control unit 200 determines whether or not the counter value is equal to the number of times N (step S25), and if not, increments the counter (step S26) and returns to step S21 to perform the process. repeat. In this way, step S24 is repeated until the counter value reaches N, and the authentication request information 212 is transmitted N times.

  In general, when a wireless communication terminal requests authentication, information corresponding to the authentication request information 212 is transmitted only once. However, the wireless communication terminal according to the present embodiment transmits the authentication request information 212 a plurality of times when receiving one authentication by repeating the process in step S25.

  Therefore, it is possible to suppress erroneous recognition of a wireless communication terminal that is not a regular wireless communication terminal as a regular wireless communication terminal, compared to a case where authentication is performed by one wireless communication. That is, the security level of the door phone system 1 can be improved without increasing the work burden on the operator.

  If the counter value is equal to the number of times N (Yes in step S25), it is determined that N transmissions have been completed. And it waits until the radio | wireless communication part 27 receives the authentication result information from the main body unit 5, and determines whether the said indoor subunit | mobile_unit 2 was normally authenticated based on the received authentication result information (step) S27).

  If the authentication fails (No in step S27), the indoor unit 2 ends the process. In this case, the indoor cordless handset 2 cannot be used in the door phone system 1. At this time, a message notifying that the authentication has failed may be displayed on the display unit 23.

  On the other hand, if the authentication is successful (Yes in step S27), the WEP key transmitted from the main unit 5 is acquired (step S28) and stored in the storage device 21. Thereby, in the subsequent wireless communication, the indoor unit 2 performs encryption based on the acquired WEP key, and transmits / receives data to / from the main unit 5. That is, the indoor cordless handset 2 is in a usable state in the door phone system 1.

  When acquiring the WEP key, the indoor unit 2 shifts to a normal standby state (step S29). Note that “normal standby” refers to standby in a usable state. That is, although not described in detail, normal processing such as notification processing when there is a visitor and extension call processing between a plurality of indoor handsets 2 is executed after being detected in the normal standby state in step S29. Is done.

  The above is mainly the operation of the indoor cordless handset 2 of the door phone system 1. Note that the processing for requesting authentication is the same for the outdoor camera 4 as described above, and therefore, the description of the operation when the outdoor camera 4 requests authentication is omitted.

  10 and 11 are flowcharts showing the operation of the main unit 5.

  When the power is turned on, the main unit 5 enters a standby state after executing predetermined initial settings. In this standby state, the main unit 5 monitors various states. For example, whether the outdoor handset 3 has been operated (visit information has been received), whether wireless communication has been requested from the indoor handset 2 or the outdoor camera 4.

  FIG. 10 shows only the monitoring steps necessary for authenticating the wireless communication terminal. Specifically, the presence / absence of wireless communication (step S31) and whether or not the reception of the authentication request information 212 has been completed (step S36).

  When the wireless communication unit 57 starts wireless communication in the standby state, the main unit 5 determines Yes in step S31. At this time, the measurement unit 500 measures the intensity of the communication radio wave received by the wireless communication unit 27 (step S32), and the wireless communication unit 27 transfers the received information to the storage device 51.

  When the information received by the wireless communication unit 27 is transferred to the storage device 51, the measurement unit 500 analyzes whether the information includes the command identifier 213 and determines whether the information is the authentication request information 212. Is determined (step S33).

  If the received information is not the authentication request information 212 (No in step S33), the main unit 5 returns to the standby state again. On the other hand, when the received information is the authentication request information 212 (Yes in step S33), the timer 502 sets the timer (step S34).

  In parallel with this processing, the measurement unit 500 generates measurement information 511 and stores the measured communication radio wave intensity according to the transmission number 216. As described above, each time the main unit 5 receives the authentication request information 212, the processing of steps S32 to S35 is executed, and the strength of the communication radio wave when the authentication request information 212 is received is stored in the measurement information 511. It is recorded together with the transmission number 216.

  A communication radio wave transmitted from a wireless communication terminal such as the indoor slave unit 2 or the outdoor camera 4 is attenuated when received by the main unit 5 and is therefore generally not received at the intensity at the time of transmission. However, since a legitimate operator can normally perform authentication work in the vicinity of the main unit 5, the intensity of the communication radio wave received during the authentication work is not extremely attenuated. Further, since the transmission of the authentication request information 212 a plurality of times is completed in a short time, it is usually unnecessary to consider that the communication state changes during this time.

  In the following description, it is assumed that communication radio waves transmitted from wireless communication terminals with an intensity of “100” and “50” are received by main body unit 5 with an intensity of “90” and “45”, respectively.

  Each time the strength of the communication radio wave is stored in the measurement information 511, the main unit 5 temporarily returns to the standby state.

  In the standby state, the main unit 5 periodically monitors whether the reception of the authentication request information 212 has been completed (step S36). If it is determined in step S36 that the reception has not been completed, the main unit 5 continues the standby state.

  Note that “reception completion” in step S36 is not completion of reception of a certain authentication request information 212 but completion of reception of all the authentication request information 212 necessary for one authentication. In the door phone system 1 according to the present embodiment, as described above, a plurality of authentication request information 212 is transmitted in the case of normal one authentication. Therefore, step S36 is provided so that authentication is started after the main unit 5 receives all the authentication request information 212 transmitted.

  The determination method in step S36 will be specifically described below. Note that the determination unit 501 acquires the number of bits n (n = 4 in the example shown here) of the authentication information 514 in advance.

  When step S <b> 36 is started, the determination unit 501 first determines whether the authentication request information 212 exists in the storage device 21. The case where the authentication request information 212 does not exist, that is, the state where the reception of the authentication request information 212 is not started yet, and in this case, the determination unit 501 determines that the reception is not completed.

  When the authentication request information 212 exists, the determination unit 501 further determines the transmission number 216 (the received maximum transmission number 216) included in the latest authentication request information 212 among the existing authentication request information 212. Obtained as number M, compare “M” with “n”, and if “M” is equal to or greater than “n”, it is determined that reception is complete.

  Thus, since the transmission request number 216 is included in the authentication request information 212, it can be efficiently determined whether or not all the authentication request information 212 has been received. Even when the nth authentication request information 212 is received, if a large number of passcode digits are input by mistake, the authentication request information 212 may be further transmitted.

  Therefore, although not shown in detail, the determination unit 501 provides a predetermined time interval from the reception of the latest authentication request information 212 to the determination in step S36. Although details will be described later, this suppresses misidentification of a wireless communication terminal (that is, a wireless communication terminal with an incorrect passcode) that has transmitted more than the required number of authentication request information 212 as a legitimate wireless communication terminal. it can. That is, it is possible to distinguish between the case where “00101” is input as the passcode and the case where “0101” is input.

  On the other hand, when “M” is less than “n”, the timer 502 set in step S34 is further referred to. In this timer 502, it is determined that reception has not been completed if a predetermined time provided for timeout has not elapsed, and it is determined that reception has been completed if it has elapsed.

  In this way, by providing a timeout by the timer 502, the process does not stop even if the transmitted authentication request information 212 is insufficient. In the present embodiment, the authentication request information 212 is transmitted a plurality of times as described above, but the authentication process can be temporarily ended even if a part of these information cannot be received. .

  FIG. 12 is a diagram illustrating an example of the measurement information 511. In the example shown in FIG. 8 and FIG. 9, the authorized wireless communication terminal transmits the authentication request information 212 four times in order from the first time with the communication radio wave having the intensity of “100, 50, 100, 50”.

  Therefore, if the wireless communication unit 57 of the main unit 5 receives this normally, as shown as measurement information 511a, the intensity of the received communication radio wave becomes “90, 45, 90, 45, 0,.・ ”Is recorded.

  However, for example, when the authentication request information 212 with the transmission number 216 of “2” has not been received, the maximum transmission number 216 (M) is “n” or more, so the timeout does not occur. As shown as information 511b, “90, 0, 90, 45, 0,...” Is recorded. Further, for example, when the authentication request information 212 whose transmission number 216 is “3” or later cannot be received, a time-out occurs, and as shown as measurement information 511c, “90, 45, 0, 0, 0,.・ 」

  An example in which an incorrect passcode is input will be described. For example, when “00101” is input as the passcode, as shown as measurement information 511d, “90, 45, 90, 45, 45,.・ ”Is recorded. Further, when “101” is input as the pass code, “90, 45, 90, 0, 0,...” Is recorded as shown as measurement information 511e.

  Although not shown in FIG. 10, when the reception of the authentication request information 212 necessary for authentication is completed (Yes in step S36), the main unit 5 deletes the authentication request information 212 received so far. Thereby, unless the authentication request information 212 is received again from the wireless communication terminal, the determination in step S36 is No even if the main unit 5 returns to the standby state.

  Next, the determination unit 501 obtains the threshold value Q based on the measurement information 511, and generates threshold value information 512 (step S37). In the example shown here, the maximum value V of the communication radio wave intensity recorded in the measurement information 511 is “90”. Therefore, the determination unit 501 calculates Q = 3 / 4V = 67.5 and the threshold value Q.

  As long as the authentication request information 212 is received (as long as the measurement information 511 is created), the strength of all communication radio waves cannot be “0”. A threshold value Q greater than "can always be determined.

  When the threshold value Q is determined in this way, when a communication radio wave having an intensity of “50, 50, 50, 50” is transmitted from the wireless communication terminal (when the input passcode is “0000”), it will be described later. In this process, “1111” is mistaken. However, as described above, since the authentication information 514 always includes the bit in the state of “0”, even if the pass code “0000” is mistakenly recognized as “1111”, this is the authentication information 514. Never match. That is, the authentication is never successful due to an incorrect passcode “0000”.

  On the other hand, since the authentication information 514 always includes a bit in the state of “1”, the pass code “0000” is not “normal” as the pass code. Therefore, even if a situation in which the pass code “0000” is mistakenly recognized as “1111” and does not match the authentication information 514 occurs, there is no problem in the authentication result.

  Thus, by obtaining the threshold value Q based on the maximum value V of the communication radio wave recorded during the authentication work, the threshold value Q can be determined according to the communication state of the environment where the door phone system 1 is installed.

  Note that, as described above, determining the threshold value Q according to the communication state corresponds to giving unlimited authentication opportunities to wireless communication terminals located within a communicable distance.

  However, as described above, since the authentication information 514 always includes a bit in the state of “0”, the strength of the communication radio wave to be transmitted is “50” in order to be normally authenticated in the door phone system 1. ”(It is difficult to reach far away), wireless communication with the main unit 5 must be possible.

  In other words, setting the authentication information 514 so that a bit in the “0” state is always included means that the position where authentication work that is normally authenticated is performed is limited to a relatively close range. This has the effect of effectively preventing unauthorized access from a distance.

  When the threshold information 512 is generated, the determination unit 501 sets a counter for designating information read from the measurement information 511 to 1 (step S38). As a result, reading is performed in order from the strength of the communication radio wave when the transmission number 216 is “1”.

  Next, the communication radio wave intensity of the transmission number indicated by the counter is acquired from the measurement information 511 (step S41), and it is determined whether or not the acquired communication radio wave intensity is “0” (step S42).

  As long as it is received by the wireless communication unit 57 of the main unit 5, the intensity of the communication radio wave at that time does not become “0”. That is, the strength recorded as “0” in the measurement information 511 indicates that the authentication request information 212 of the corresponding transmission number 216 has not been received. Accordingly, the determination in step S42 corresponds to determining whether or not the authentication request information 212 that includes the transmission number 216 having the value indicated by the counter has been received.

  By making such a determination, the door phone system 1 can distinguish between a case where the communication radio wave that received the authentication request information 212 was weak and a case where the authentication request information 212 could not be received in the first place.

  When the intensity of the acquired communication radio wave is not “0” (No in step S42), the state of the communication radio wave at that time is determined based on the intensity of the communication radio wave when the authentication request information 212 is received. Specifically, referring to the threshold information 512, it is determined whether or not the intensity is larger than the threshold Q obtained in step S37 (step S43).

  If the intensity of the communication radio wave is larger than the threshold value Q (Yes in step S43), “1” is stored in the bit corresponding to the value indicated by the counter (bit of the determination information 513) (step S44). On the other hand, when the intensity of the communication radio wave is equal to or less than the threshold value Q (No in step S43), “0” is stored in the bit corresponding to the value indicated by the counter (bit of the determination information 513) (step S45). That is, the determination information 513 is generated bit by bit by steps S44 and S45.

  When 1-bit information is written in the determination information 513 (when step S44 or S45 is executed), the determination unit 501 increments the counter (step S46) and proceeds to step S41 to read the next information from the measurement information 511. Return and repeat the process.

  In this way, determination information 513 is generated until the intensity of the communication radio wave acquired in step S41 becomes “0” (until determined as Yes in step S42).

  FIG. 13 is a diagram illustrating determination information 513. The determination information 513a, 513b, 513c, 513d, and 513e illustrated in FIG. 13 indicates the determination information 513 generated based on the measurement information 511a, 511b, 511c, 511d, and 511e illustrated in FIG.

  As apparent from the determination information 513a, “0101” is normally combined from the measurement information 511a generated when the passcode “0101” is normally received.

  On the other hand, as is clear from the determination information 513b and 513c, when even a part of the transmitted authentication request information 212 cannot be received, the transmitted passcode “0101” cannot be normally combined. In other words, in the door phone system 1 according to the present embodiment, authentication does not succeed only by chance that communication is successful. Therefore, it is possible to effectively exclude a third party who tries to access illegally from a distance from the main unit 5 (a case where the communication state is relatively poor and reception is not possible).

  Further, as apparent from the judgment information 513d and 513e, even if the number of digits of the passcode is input incorrectly, the input passcode is correctly combined, resulting in an incorrect passcode. Therefore, the situation of successful authentication is suppressed.

  If it determines with Yes in step S42, the determination part 501 will complete | finish the production | generation of the determination information 513, and the authentication part 503 will determine whether the determination information 513 and the authentication information 514 correspond (step S47).

  If they do not match (No in step S47), the main unit 5 does not recognize the indoor handset 2 (the wireless communication terminal that has requested authentication) as a legitimate wireless communication terminal, and transmits a rejection notification as authentication result information (step S48). ).

  On the other hand, if they match (Yes in step S47), the main unit 5 recognizes the indoor handset 2 (the wireless communication terminal that has requested authentication) as a legitimate wireless communication terminal, and transmits a WEP key as authentication result information (step). S49).

  After executing step S48 or S49, the main unit 5 ends the authentication process and returns to the standby state shown in FIG.

  As described above, in the door phone system 1 according to the present embodiment, the input passcode is associated with the number of times the authentication request information 212 is transmitted and the strength of the communication radio wave when the authentication request information 212 is transmitted. It is possible to prevent erroneous registration of an unauthorized wireless communication terminal without requiring a complicated passcode. Therefore, security in wireless communication can be ensured without increasing the burden on the operator.

  Although detailed description is omitted, terminal identification information may be included in the authentication request information 212 on the assumption that the authentication request information 212 is received from a plurality of wireless communication terminals. At this time, authentication for a plurality of wireless communication terminals may be performed in parallel, or may be performed one by one (the terminal that has been delayed is put on standby or is temporarily rejected).

  Further, for example, when the main unit 5 is installed in each of two households, if the mutual recognition information 514 is common, each indoor unit 2 may be registered in the wrong main unit 5. Therefore, it is preferable that the authentication information 514 (passcode) is unique for each main unit 5.

  On the other hand, when unique authentication information 514 is given to each main unit 5, the number of bits of the authentication information 514 increases, and the number of times of communication for authentication (the number N of times of transmitting the authentication request information 212) increases. Thus, registration takes time.

  In order to avoid this, a plurality of types of authentication information 514 may be prepared in advance, and one of them may be initially set as the authentication information 514 to be used. Further, it may be configured such that the operator can change the initially set authentication information 514 by operating the operation unit 52 so that the initially set authentication information 514 does not overlap in the example of the two-family house.

  Further, when installing the main unit 5, the authentication information 514 may be arbitrarily determined by the operator and input by operating the operation unit 52 of the main unit 5.

  Also, the indoor cordless handset 2 of the door phone system 1 encrypts and transmits the authentication request information 212 with a common key (stored in advance if the device is a legitimate manufacturer). The main unit 5 decrypts the received authentication request information 212 with the common key and decrypts the manufacturer identification code 214. Then, it is determined whether or not it matches the information stored on the main unit 5 side. If they do not match, it is determined that the authentication has failed. Since there is a high possibility that a camouflaged terminal is generally not a product of a legitimate manufacturer, the main unit 5 can eliminate a camouflaged terminal whose radio wave intensity has been illegally strengthened, and can ensure a security level. .

<2. Modification>
Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made.

  For example, in the above-described embodiment, the functional blocks such as the communication control unit 200 have been described as being realized by software by a program. However, part or all of the functional blocks may be realized by hardware by a dedicated circuit.

  Moreover, each process shown in the said embodiment is an illustration to the last, Comprising: The content and order are not limited. That is, as long as the same effect can be obtained, the contents and order may be changed as appropriate.

  In the above embodiment, the authentication information 514 itself is input as the passcode, but the present invention is not limited to this. For example, the number of bits of the authentication information 514 and a number converted into a decimal number may be input as the passcode. That is, when the authentication information 514 is “0101”, “4 (bit number), 9 (decimal number representation of 101)” may be input as the passcode. In general, the binary number not only has a large number of digits but is also a number that is difficult for humans to understand (store), but the pass code is expressed in decimal numbers to reduce the burden on the operator.

  Further, the number of bits of the authentication information 514 may be determined in advance between the main unit and the wireless communication terminal. In this case, the security level is reduced, but the burden on the operator is reduced. That is, it may be determined according to the security level required for the network.

  Further, the authentication unit 503 does not necessarily have to make a determination based on the determination information 513 described in the above embodiment. For example, when the authentication information 514 is 4 bits, it is determined that the authentication has failed when the fifth authentication request information 212 is received, or when the third authentication request information 212 is received and a timeout occurs. May be.

  Further, the wireless communication terminal is not limited to dedicated hardware such as the indoor cordless handset 2 or the outdoor camera 4, and may be a general computer. The same applies to the main unit 5.

  Moreover, in the said embodiment, although calculated | required by calculation based on the measurement information 511, the threshold value Q may be previously determined as a fixed value as an appropriate value. In this case, it is preferable to set the authentication request information 514 so as to always include one or more states of “1”. Even when “1” is transmitted, since the wireless communication terminal in the range not exceeding the fixed threshold Q on the receiving side is determined to be “0”, authentication fails as a result. That is, by always transmitting “1” from the wireless communication terminal, the range (distance) in which authentication is permitted can be limited in advance, and the security level can be improved.

  In the above embodiment, if the strength of the communication radio wave at this time is equal to or less than the threshold value Q even though the authentication request information 212 is received, it is determined that the state of the communication radio wave is “0”. In other words, for the authentication request information 212 received with an intensity less than or equal to the threshold Q and greater than “0”, the state of the communication radio wave is determined to be “0”. However, another threshold value for determining whether or not the state of the communication radio wave is “0” may be set.

It is a figure which shows the door phone system which is a communication system in this invention. It is a block diagram which shows the structure of an indoor subunit | mobile_unit. It is a figure which shows the functional block of an indoor subunit | mobile_unit with the flow of information. It is a figure which illustrates the structure of authentication request information. It is a block diagram which shows the structure of an outdoor camera. It is a block diagram which shows the structure of a main body unit. It is a figure which shows the functional block of a main body unit with the flow of information. It is a flowchart which shows operation | movement of an indoor subunit | mobile_unit. It is a flowchart which shows operation | movement of an indoor subunit | mobile_unit. It is a flowchart which shows operation | movement of a main body unit. It is a flowchart which shows operation | movement of a main body unit. It is a figure which shows the example of measurement information. It is a figure which illustrates determination information.

Explanation of symbols

1 door phone system 2 indoor unit 20, 40, 50 CPU
200 Communication control unit 201, 502 Timer 21, 41, 51 Storage device 210, 410, 510 Program 211 Pass code 212 Authentication request information 215 Time information 216 Transmission number 22, 42, 52 Operation unit 23, 43, 53 Display unit 27, 47, 57 Wireless communication unit 3 Outdoor unit 4 Outdoor camera 5 Main unit 500 Measurement unit 501 Determination unit 503 Authentication unit 511, 511a, 511b, 511c, 511d, 511e Measurement information 512 Threshold information 513, 513a, 513b, 513c, 513d , 513e judgment information 514 authentication information

Claims (9)

A repeater that performs wireless communication with one or more wireless communication terminals,
A wireless communication unit that transmits and receives information by communication radio waves;
A storage unit for storing authentication information consisting of a plurality of bits;
Each time the wireless communication unit receives one authentication request information from a wireless communication terminal, a measurement unit that measures the strength of a communication radio wave when the one authentication request information is received;
Based on the measurement result of the measurement unit, the communication radio wave intensity when the one authentication request information is received is compared with a threshold, and the state of the communication radio wave when the one authentication request information is received is 1 or A determination unit that determines to be 0;
An authentication unit that authenticates the wireless communication terminal based on a determination result of the determination unit and authentication information stored in the storage unit;
A repeater comprising: The repeater according to claim 1,
The authentication information is information including at least one 1-state bit and at least one 0-state bit;
The said determination part determines the said threshold value based on the measurement result of the said measurement part, The repeater characterized by the above-mentioned. A computer-readable program, wherein the execution of the program by the computer is performed on the computer,
A storage step of storing authentication information consisting of a plurality of bits;
A wireless communication process for transmitting and receiving information by communication radio waves;
In the wireless communication step, each time one authentication request information is received from a wireless communication terminal, a measurement step for measuring the strength of a communication radio wave when the one authentication request information is received;
Based on the measurement result in the measurement step, the communication radio wave intensity when the one authentication request information is received is compared with a threshold, and the state of the communication radio wave when the one authentication request information is received is 1 or A determination step of determining that it is 0;
An authentication step of authenticating the wireless communication terminal based on the determination result in the determination step and the authentication information stored in the storage step;
A program characterized in that is executed. A wireless communication terminal that performs wireless communication with a repeater,
An operation unit that accepts a passcode;
A storage unit for storing a passcode received by the operation unit;
A wireless communication unit that transmits information to the repeater by communication radio waves;
Based on the pass code stored in the storage unit, the number of times of transmission of the authentication request information to be transmitted to the repeater is determined, and the communication radio wave intensity at the time of transmitting the one authentication request information is the one authentication A communication control unit that determines the request information and controls the wireless communication unit;
A wireless communication terminal comprising: The wireless communication terminal according to claim 4,
The wireless communication terminal, wherein the communication control unit determines the number of transmissions according to the number of bits of a passcode received by the operation unit. A computer-readable program, wherein the execution of the program by the computer is performed on the computer,
An input process for accepting a passcode;
A storage step of storing the passcode received in the input step;
Based on the passcode stored in the storage step, the number of times determination step of determining the number of times authentication request information is transmitted,
A strength determination step for determining the strength of a communication radio wave when transmitting one authentication request information for each of the one authentication request information;
A wireless communication step of transmitting authentication request information to a repeater for the number of transmissions determined in the number of times determination step with the communication radio wave of the strength determined in the strength determination step;
A program characterized in that is executed. A communication system in which one or more wireless communication terminals perform wireless communication with a repeater,
The repeater is
A wireless communication unit that transmits and receives information by communication radio waves;
A storage unit for storing authentication information consisting of a plurality of bits;
Each time the wireless communication unit receives one authentication request information from a wireless communication terminal, a measurement unit that measures the strength of a communication radio wave when the one authentication request information is received;
Based on the measurement result of the measurement unit, the communication radio wave intensity when the one authentication request information is received is compared with a threshold, and the state of the communication radio wave when the one authentication request information is received is 1 or A determination unit that determines to be 0;
An authentication unit that authenticates the one wireless communication terminal based on a determination result of the determination unit and authentication information stored in the storage unit;
With
Wireless communication terminal
An operation unit that accepts a passcode;
A storage unit for storing a passcode received by the operation unit;
A wireless communication unit that transmits information to the repeater by communication radio waves;
Based on the pass code stored in the storage unit, the number of times of transmission of the authentication request information to be transmitted to the repeater is determined, and the strength of the communication radio wave when transmitting the one authentication request information is the one authentication A communication control unit that determines the request information and controls the wireless communication unit;
A communication system comprising: A communication system according to claim 7,
The communication control unit includes a transmission number in the authentication request information,
The measurement unit associates a transmission number included in authentication request information with the strength of a communication radio wave when the authentication request information is received. A communication method in which one or more wireless communication terminals perform wireless communication with a repeater,
A first storage step of storing authentication information consisting of a plurality of bits in the repeater;
An input step of accepting a passcode in the wireless communication terminal;
A second storage step of storing the passcode received in the input step in the wireless communication terminal;
A number-of-times determining step of determining the number of times of transmission of the authentication request information based on the passcode stored in the second storage step;
A strength determination step for determining the strength of a communication radio wave when transmitting one authentication request information for each of the one authentication request information;
A wireless transmission step of transmitting authentication request information from the wireless communication terminal by the number of transmissions determined in the number-of-times determination step with the communication radio wave of the strength determined in the strength determination step;
A wireless reception step of receiving the authentication request information transmitted in the wireless transmission step;
In the wireless reception step, each time one authentication request information is received from the wireless communication terminal, a measurement step of measuring a communication radio wave intensity when the one authentication request information is received;
Based on the measurement result in the measurement step, the communication radio wave intensity when the one authentication request information is received is compared with a threshold, and the state of the communication radio wave when the one authentication request information is received is 1 or A determination step of determining that it is 0;
An authentication step of authenticating the wireless communication terminal based on the determination result in the determination step and the authentication information stored in the first storage step;
A communication method comprising:

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