JP4737146B2 - Portable terminal device, key, and wireless authentication system - Google Patents

Description

  The present invention relates to a wireless authentication system that performs wireless authentication between a mobile terminal device and a key, and sounds a warning sound when a key that has been successfully wirelessly authenticated with the mobile terminal device fails in wireless authentication. The present invention relates to a mobile terminal device that performs wireless authentication with a plurality of keys, and a key that performs wireless authentication with the mobile terminal device.

A mobile terminal device typified by a mobile phone and a key (a key is a wireless communication circuit having at least an antenna and an IC chip, and information stored in the IC chip is transmitted and received between the mobile terminal device and the antenna via the antenna. An anti-theft system is proposed that prevents the object to which the key is attached from being stolen by using a wireless authentication technique (for example, Patent Document 1) performed between the key and the object. For example, as shown in the schematic diagram of the conventional anti-theft system shown in FIG. 5, keys are attached to the PC 911, the camera 912, and the sunglasses 13, and the authentication areas (shown in FIGS. 5 (a) and 5 (b)). Any one of the PC 911, the camera 912, and the sunglasses 13 located inside the circle centered on the mobile terminal device 91) is a non-authentication area (the mobile terminal shown in FIGS. 5A and 5B). When it is carried to the outside of the circle centering on the device 91, there is one in which the object carried to the portable terminal device 91 or the non-authentication area emits a notification sound.
Japanese Patent No. 293276

  However, the above antitheft system has the following problems. That is, as the number of objects to which keys are attached increases, when the mobile terminal device 91 at the center of the authentication area moves, the position of any one of the objects may change from the authentication area to the non-authentication area. As a result, the mobile terminal device or the key may output an alarm sound even though the object is not carried. The problem that such unnecessary alarm sounds frequently occur is a major problem related to the reliability of the anti-theft system.

  The present invention has been made in view of the above circumstances, and suppresses the output of an alarm sound even if the number of objects to which keys are attached increases even though the objects are not carried. An object of the present invention is to provide a portable terminal device and a key that can be used, and a wireless authentication system.

A first aspect of the invention is a wireless unit that performs wireless communication with a first key or a second key, and a detection unit that detects reception intensity of radio waves received from the first key or the second key by the wireless unit. And a notification unit, and a message including communication information of the first key and the second key transmitted from the first key by the wireless unit, and receiving the message according to the communication status A control unit configured to perform a notification process , wherein the control unit receives from the first key out of reception strengths from the first key and the second key detected by the detection unit at a predetermined time interval; In the message transmitted from the first key, the radio wave reception intensity changes within a predetermined range, and the radio wave reception intensity received from the second key does not change from the previous reception intensity. The second key is transmitted to the mobile terminal device in the communication information of When the electric field strength when the changes from the field strength of the last transmission, a mobile terminal apparatus that the control to perform the notification process to the notification unit, a reception strength between the key and the mobile terminal device, from the key The communication information can be used to grasp the positional relationship between the key and the mobile terminal device, and the information between the keys can be used to grasp the positional relationship between the mobile terminal device and the key before performing the notification process. Can

The second invention is a wireless authentication system including a mobile terminal device and the key in the first invention, accurately grasped the positional relationship between the portable terminal apparatus and the key to the notification determination be able to.

  According to the portable terminal device, the key, and the wireless authentication system of the present invention, even if the number of objects to which the key is attached increases, an alarm sound is output even though the object is not carried. Can be suppressed.

  Hereinafter, a wireless authentication system according to an embodiment of the present invention will be described. First, referring to an example of the configuration diagram of the wireless authentication system of the embodiment of the present invention shown in FIG. 1 and another example of the configuration diagram of the wireless authentication system of the embodiment of the present invention shown in FIG. An outline of processing by the wireless authentication system according to the embodiment of the present invention will be described.

  First, a wireless authentication technique performed between the mobile terminal device and the key will be described. In FIG. 1, an area surrounded by a circle centering on the mobile terminal device 1 and in which the mobile terminal device 1 can communicate with the keys 21, 22, and 23 located inside the circle is referred to as an authentication area. Conversely, an area outside the circle centered on the mobile terminal device 1 and in which the mobile terminal device 1 cannot communicate with the keys 21, 22, 23 located outside the circle is referred to as an unauthenticated area. ing. When the key 21, 22, 23 is present in the non-authentication area, the mobile terminal device 1 has a weak reception strength (RSSI: Received Signal Strength Indicator) received from the keys 21, 22, 23. It is determined that the authentication between the terminals 22 and 23 has failed (hereinafter, the state in which the mobile terminal device and the key have failed authentication may be referred to as a standby mode). On the other hand, when the keys 21, 22, and 23 exist in the authentication area, the mobile terminal device 1 performs wireless communication with the keys 21, 22, and 23 to receive an authentication code, and the authentication code is a predetermined one. If it is, it is determined that the authentication has succeeded (hereinafter, the state in which the mobile terminal device and the key have been successfully authenticated may be referred to as an authentication mode). To do. Hereinafter, the content of data transmitted and received for the wireless authentication process between the mobile terminal device 1-keys 21, 22, and 23 will be described.

  The mobile terminal device 1 transmits a code for authentication (hereinafter referred to as an identification ID) assigned at the time of pairing with the keys 21, 22, and 23 in advance at a constant cycle, The keys 21, 22, and 23 are waiting to receive an identification ID transmitted from the mobile terminal device 1 in a slot with a fixed period assigned to each key. In this process and subsequent processes, the processes of the keys 21, 22, 23 and the portable terminal device 1 may be reversed.

  When the keys 21, 22, and 23 are located in a non-authentication area where the mobile terminal device 1 cannot communicate, the keys 21, 22, and 23 cannot receive the identification ID transmitted from the mobile terminal device 1. , Keep the standby mode. Thereafter, when the keys 21, 22, 23 move from the non-authentication area to the authentication area, the keys 21, 22, 23 receive the identification ID, and the identification ID received from the mobile terminal device 1 and the keys 21, 22, 23 As soon as it is determined that the previously paired identification ID stored in the device matches, the mobile terminal device 1 is informed that these identification IDs match (that is, there is a key paired within a certain distance). Notification is made and the mode is shifted to the authentication mode.

When the mobile terminal device 1 is notified from the keys 21, 22, and 23 that the identification IDs match, the mobile terminal device 1 periodically authenticates with the keys 21, 22, and 23 using the challenge and response method. Specifically, when the mobile terminal device 1 receives a signal notifying that the identification IDs match from the keys 21, 22, and 23, the mobile terminal device 1 transmits a challenge request to the keys 21, 22, and 23, and receives the challenge request. The keys 21, 22, and 23 transmit a challenge signal generated by generating a random number to the mobile terminal device 1, and the mobile terminal device 1 that has received the challenge signal generates the challenge signal by performing encryption processing. The response signal is transmitted to the keys 21, 22, and 23. The keys 21, 22, and 23 that have received the response signal determine that the authentication is successful when the decrypted response signal matches the challenge signal, and decrypt the decrypted response signal. If the response signal and the challenge signal do not match, it is determined that the authentication has failed. In the authentication mode, various signals transmitted and received between the mobile terminal device 1 and the keys 21, 22, and 23 are
Since the identification ID of the mobile terminal device 1 and the identification IDs of the keys 21, 22, and 23 for transmitting or receiving the signal are included, the mobile terminal device 1 includes the keys 21, 22, 23, it is determined which key 21, 22, 23 is transmitted by various signals, and the keys 21, 22, 23 are also keys included in the various signals transmitted by the mobile terminal device 1. With reference to the identification IDs 21, 22, and 23, it is determined whether or not various signals are transmitted to the own device. When the authentication is successful, the mobile terminal device 1 performs the above process again at a predetermined time interval. On the other hand, when the authentication is unsuccessful, the mobile terminal device 1 shifts to a standby mode and starts transmitting an identification ID. Even if the transmission / reception of the signal is interrupted during authentication using the challenge-and-response method between the mobile terminal device 1-keys 21, 22, and 23, the mobile terminal device 1 shifts to the standby mode and is identified. The transmission of the ID is started.

  The mobile terminal device 1 performs wireless authentication processing with the keys 21, 22, and 23 as described above, and receives authentication from the keys 21, 22, and 23 when the authentication with the keys 21, 22, and 23 is successful. Measurement of reception intensity (RSSI) of radio waves transmitting various signals is started. The mobile terminal device 1 stores the reception intensity every time it measures the reception intensity (RSSI) of the radio wave transmitting various signals in the authentication mode. In FIG. 1A, at a certain time t1. The reception intensity (RSSI1) of the radio wave received from the key 21 is “10”, the reception intensity (RSSI2) of the radio wave received from the key 22 is “7”, and the reception intensity (RSSI3) of the radio wave received from the key 23 is “7”. , And are stored as

  FIG. 2 shows another example of the configuration diagram of the wireless authentication system according to the embodiment of the present invention. The keys 21, 22, and 23 are configured to be able to measure the reception intensity of radio waves received from keys other than the portable terminal device and the own device (the configuration will be described later). FIG. 2 shows a case where the key 22 measures their reception intensity. In addition, although the portable terminal device 1 is also measuring the reception intensity | strength of the electromagnetic wave received from the keys 21, 22, and 23, when the key moves like FIG. 2, since the measured reception intensity does not change, FIG. Does not show the reception intensity measured by the mobile terminal device.

  The key 22 stores the reception intensity every time the reception intensity (RSSI) of radio waves transmitted from the portable terminal device 1 and the keys 21 and 23 is transmitted. ), At a certain time t1, the reception intensity (RSSI4) of the radio wave received from the key 21 is "6", the reception intensity (RSSI5) of the radio wave received from the mobile terminal device 1 is "7", and the radio wave received from the key 23 Reception strength information (RSSI6) is stored as “12”, and when the key 22 transmits to the mobile terminal device 1, the reception strength information of the radio waves received from the keys 21 and 23 (RSSI4 is “6” and RSSI6). Is transmitted including “12”).

  After that, as shown in FIG. 6B, when the object to which the key 22 is attached is carried around the mobile terminal device 1 (time t <b> 2), the key 22 is received from the key 21. The radio wave reception intensity (RSSI4) changes to "3", and the key 22 changes to the radio wave reception intensity (RSSI6 changes to "6" (the key 22 receives the radio wave reception intensity from the mobile terminal device 1). (RSSI5) does not change.) These reception strengths are similarly stored once in the key 22, and when the key 22 transmits toward the mobile terminal device 1, reception of radio waves received from the keys 21 and 23 is received. Transmit including the strength information (RSSI4 is “3”, RSSI6 is “6”).

  On the other hand, the mobile terminal device 1 can obtain the reception intensity from the radio wave transmitted from each key, and can obtain the reception intensity between the keys based on the reception intensity information included in the message transmitted from each key.

For example, in the mobile terminal device 1, when the received strength information received from the key 22 at time t 1 is compared with the received electric field strength information received at time t 2, the received strength (RSSI 4) between the key 22 and the key 21 is “6”. ”To“ 3 ”, and information in which the reception strength (RSSI6) between the key 22 and the key 23 is changed from“ 12 ”to“ 6 ”can be obtained. At the same time, in the mobile terminal device 1, considering that the reception intensity (RSSI5) transmitted from the key 22 does not change to “7” at the time t1 and the time t2, the key 21 and the key 23 are It can be determined that the distance between the mobile terminal device 1 and the key 22 is increasing at t1 and time t2, and a notification operation such as outputting a warning sound is performed in the mobile terminal device 1.

  As described above, a certain key 22 is made to measure the reception intensity of radio waves transmitted by other keys 21 and 23, and when the key 22 transmits a message to the mobile terminal device 1, it is attached and received as reception intensity information. Thus, in the mobile terminal device 1, in addition to the positional relationship between a certain key and the mobile terminal device 1, information for determining the positional relationship between the keys can be obtained. Thereby, even when the object to which the key 22 is attached moves along a circle centering on the mobile terminal device 1, the positional relationship can be grasped and a notification operation such as a warning sound can be performed. Therefore, the user of the mobile terminal device 1 can notice that the object is being carried.

  In addition, although the structure which makes the carried key 22 measure the reception intensity | strength of the electromagnetic wave from the other keys 21 and 23 was demonstrated, the portable terminal device 1 is also provided by providing the other keys 21 and 23 with the same structure. Similar effects can be obtained. For example, the key 21 is made to measure the reception intensity of the radio wave transmitted by the other keys 22 and 23, and when the key 21 transmits to the mobile terminal device 1, the reception including the data indicating the state of the key 22 and the key 23 is included. When the configuration for transmitting the strength information is provided, in the mobile terminal device 1, the reception strength between the key 21 and the mobile terminal device 1 does not change, and the reception strength of the radio wave between the carried key 22 and the key 23 changes. In such a case, a notification operation such as an alarm sound is performed in the mobile terminal device 1.

  Next, the configuration of a key for measuring the reception intensity of a radio wave transmitted by another key and transmitting an alarm request signal to the mobile terminal device according to the reception intensity, and the specific flow of the process will be described. FIG. 3 shows a functional block diagram of the portable terminal device and the key according to the embodiment of the present invention.

  The mobile terminal device 1 according to the embodiment of the present invention includes a wireless authentication unit 11, a mobile communication wireless control unit 12, an output unit 13, an operation key 14, and a mobile terminal control unit 15. The portable key 2 according to the embodiment of the present invention includes a wireless authentication unit 21.

  In the wireless authentication unit 11 of the mobile terminal device 1, the authentication wireless control unit 111 is configured to transmit radio waves for short-range communication or UWB (Ultra Wide Band) used in RFID (Radio Frequency Identification) via an antenna. : Ultra-wideband radio) or the like is used to control transmission / reception of a signal including the identification code of the key 2 set as a pair with the portable terminal device 1 by pairing processing based on a predetermined communication protocol. The authentication wireless control unit 111 includes circuits such as an amplifier circuit, a modulation circuit, a demodulation circuit, an encoding circuit, and a decoding circuit.

The authentication control unit 113 calculates the reception intensity of radio waves used in wireless communication (for example, based on the voltage level and S / N ratio of radio waves input to the demodulation circuit, the error rate of data decoded by the decoding circuit, etc.) And the received intensity is determined to be greater than or less than a preset threshold value (numerical value for distinguishing the authentication area and the non-authentication area). If the measured reception intensity is equal to or greater than the threshold, the authentication control unit 113 subsequently acquires the identification ID of the key 2 included in the decoded data in advance by a pairing process performed with the key 2. If it matches, the usage restriction release signal notifying that the authentication with the key 2 is successful is output to the mobile terminal control unit 15, and if it does not match, the authentication with the key 2 is failed. The use restriction request signal to be notified is output to the mobile terminal control unit 15. On the other hand, if the measured reception intensity is less than the threshold value, the authentication control unit 113 outputs a use restriction request signal notifying that the authentication with the key 2 has failed to the mobile terminal control unit 15.

  Further, if the measured reception intensity is equal to or greater than the threshold value, the authentication control unit 113 receives the measured reception intensity in association with the identification ID of the key 2 included as data in the radio wave whose reception intensity is measured. The intensity is stored in the intensity storage unit 112. Further, even if the measured reception intensity is less than the threshold value, the authentication control unit 113 uses the measured reception intensity as long as the identification ID can be specified from the data obtained by decoding the radio wave having the reception intensity. Is stored in the reception intensity storage unit 112 in association with the identification ID of the key 2 included as data in the measured radio wave. Each time the authentication control unit 113 receives a radio wave including the identification ID from the key 2 (or every time the radio wave is received a predetermined number of times), the authentication control unit 113 sequentially receives the measured reception intensity in association with the identification ID of the key 2. The intensity is stored in the intensity storage unit 112.

  Further, the authentication control unit 113 measures the reception intensity of radio waves used in wireless communication, associates the reception intensity information included in the decoded data with the identification ID for each key, and stores the reception intensity information in the reception intensity recording unit 112. Remember.

  Whenever a new pair of reception strength and identification ID is stored in the reception strength storage unit 112, the reception strength processing unit 114 receives the reception strength of the pair and the identification stored in the reception strength storage unit 112. Of the reception strengths specified by the ID, the next new reception strength is compared. Similarly, each time a new pair of reception strength information and identification ID is recorded in the reception strength storage unit 112, the reception strength information of the pair and the identification ID recorded in the reception strength recording unit 112 are used. Of the specified received strength information, next, the new received strength information is compared.

  When the two types of information are compared, for example, if there is a difference that the received intensity can be regarded as the same and the received intensity information cannot be regarded as the same, the alarm request signal is sent to the portable terminal control unit. 15 is output. The “difference that cannot be regarded as the same” includes, for example, a state in which the new reception strength information is increased or decreased by ± 20% or more compared to the next new reception strength information. .

  The portable terminal control unit 15 places restrictions on the execution of the various functions that can be executed by the portable terminal device 1 during the period when the use restriction request signal is notified from the authentication control unit 113. As an example of the restriction by the mobile terminal control unit 15, control is performed so that the mobile communication radio control unit 12 that controls radio communication processing with the mobile phone base station does not perform part or all of the communication processing. Control so that the speaker 131 of the output unit 13 does not output sound, the microphone 132 does not pick up sound, the LCD 133 does not display sound, or the operation keys 14 do not accept input operations. And so on. Further, when the alarm request signal is notified from the authentication control unit 113, the portable terminal control unit 15 outputs a predetermined notification method, for example, the sound on the speaker 131 of the output unit 13, or the LCD 133 outputs an image or Control to display characters.

In addition, in the wireless authentication unit 24 of the key 2, the wireless control unit 241 transmits, via an antenna, radio waves for short-range communication used in RFID (Radio Frequency Identification) or UWB (Ultra Wide Band): The transmission / reception of a signal including the identification code of the portable terminal device 1 set as a pair with the key 2 by pairing processing is controlled based on a predetermined communication protocol. The wireless control unit 241 includes circuits such as an amplifier circuit, a modulation circuit, a demodulation circuit, an encoding circuit, and a decoding circuit. The authentication processing unit 243 calculates based on reception intensity of radio waves used in wireless communication (for example, voltage level and S / N ratio of radio waves input to the demodulation circuit, error rate of data decoded by the decoding circuit, etc.) Measured). The reception strength storage 242 is stored in the authentication processing unit 2
The identification ID obtained by demodulating the data transmitted from the key other than the mobile terminal device 1 and the key 2 processed in 43 and the reception intensity of each are stored. The key control unit 244 is transmitted from a key other than the key 2 recorded in the reception strength recording unit 242 when the wireless portable terminal device 1 and the key 2 perform pairing processing or authentication processing periodically. The identification ID and the received intensity information are combined to generate data to be transmitted to the mobile terminal device 1, and a process of transmitting the data via the wireless control unit 241 is performed.

  Next, the flow of processing by the portable terminal device and the key according to the embodiment of the present invention configured as described above is shown in FIG. 4, and wireless communication performed by the portable terminal device and the key according to the embodiment of the present invention is shown in FIG. A description will be given with reference to a processing time chart. In addition, the time chart shown in FIG. 4 has shown the timing with which a signal is transmitted / received by the radio | wireless authentication system which consists of one portable terminal device 1 and two keys (key 21 and key 22).

  The mobile terminal device 1 that has succeeded in wireless authentication with each of the keys 21 and 22 and has shifted to the authentication mode uses the modulated signals modulated by various signals in the slots assigned to the keys 21 and 22 respectively. 21 and the key 22. The mobile terminal device 1 first transmits a challenge request (denoted as REQ in FIG. 4) to the slot assigned to the key 21 (step 11). When the key 21 receives a challenge request from the mobile terminal device 1 (step 21a), the key 21 transmits a challenge signal generated by generating a random number (referred to as RES in FIG. 4) to the mobile terminal device 1 ( Step 22a).

  When the mobile terminal device 1 receives a challenge signal from the key 21 (step 12), the mobile terminal device 1 measures the reception strength of the signal and receives the measured reception strength (RSSI K1) in association with the identification ID of the key 21. Store in the intensity storage unit 112. Further, since the challenge signal includes reception intensity information to be described later, the reception intensity information is recorded in the reception intensity recording unit 112 together with the identification ID.

  On the other hand, the key 22 measures the reception strength of the challenge signal from the key 21 (step 22b), and stores the received strength information as the received strength information by associating the measured received strength (RSSI K1 ′) with the identification ID of the key 21. Store in the unit 242.

  Subsequently, the mobile terminal device 1 transmits a challenge request to the slot assigned to the key 22 (step 13).

  When the key 22 receives the challenge request from the mobile terminal device 1 (step 23b), the key 22 measures the reception strength of the signal, and associates the measured reception strength (RSSI T2) with the identification ID of the mobile terminal device 1. Stored in the received intensity storage unit 242. Further, the key 22 transmits a challenge signal generated by generating a random number to the mobile terminal device 1 (step 24b). At this time, in the message transmitted to the mobile terminal device 1, the reception strength (RSSI K1 ′) recorded from the key 21 and the identification ID of the key 21 recorded in the reception strength recording unit 242 in step 22 b are used as reception strength information. Send including.

  On the other hand, the key 21 measures the reception intensity of the challenge request (step 23a), and stores the measured reception intensity (RSSI T2 ′) and the identification ID of the mobile terminal device 1 in the reception intensity storage unit 242 in association with each other. .

When the mobile terminal device 1 receives the challenge signal from the key 22 (step 14), the mobile terminal device 1 measures the reception strength of the signal and receives the measured reception strength (RSSI K2) and the identification ID of the key 22 in association with each other. Store in the intensity storage unit 112. In addition, reception intensity information (RSSI K1 ′) in the challenge signal is also recorded in the reception intensity recording unit 112.

  On the other hand, the key 21 measures the reception intensity of the challenge signal (step 24a), and associates the measured reception intensity (RSSI K2 ′) with the identification ID of the key 22 in the reception intensity storage unit 242 as reception intensity information. Remember.

  Further, again, the portable terminal device 1 repeats the processing from step 11 to step 14 described above, the key 21 repeats the processing from step 21a to step 24a, and the key 22 repeats the processing from step 21b to step 24b. Since the description of the processing is as described above, it is omitted.

  In FIG. 4, the reference numerals from step 15 to step 18 are used for the process by the mobile terminal device 1 that is repeated, and the reference numerals from step 25 a to the step 28 a are used for the process by the key 21 that is repeated. The reference numerals from step 25b to step 28b are respectively assigned to the processes.

  In FIG. 4, the reception strength measured by the key 21 in step 25a is (RSSI T3), the reception strength measured by the key 21 in step 27a (RSSI T4 ′), and the reception strength measured by the key 21 in step 28a. (RSSI K4 ′), the reception strength measured by the key 22 in step 25b (RSSI T3 ′), the reception strength measured by the key 22 in step 26b (RSSI K3 ′), and the reception strength measured by the key 22 in step 27b. Is described as (RSSI T4 ′).

  The portable terminal device 1 records the reception intensity of the challenge signal transmitted from the key shown in FIG. 4 in the reception intensity recording unit 112 and also records the reception intensity information in the challenge signal. When the mobile terminal device 1 obtains at least twice the reception strength received individually from other keys and the reception strength information included in the message, the mobile terminal device 1 takes a difference between the information.

  For example, the received intensity transmitted from the key 21 is “[RSSI K (2n + 1)] − [RSSI K (2n−1)]” (where n = 1, 2, 3,...) In the received strength information in the transmitted message, “[RSSI K (2n + 2) ′] − [RSSI K (2n) ′]” (where n = 1, 2, 3,...) In the reception strength to be transmitted, “[RSSI K (2n + 2)] − [RSSI K (2n)]” (where n = 1, 2, 3,...), Reception in the message transmitted from the key 21. In the intensity information, “[RSSI K (2n + 1) ′] − [RSSI K (2n−1) ′]” (where n = 1, 2, 3,...).

Then, based on the respective calculation results, it is determined whether or not the latest received intensity and received intensity information at the time of measurement have increased or decreased compared with the previous received intensity and received intensity information. When the above difference is “0”, it should be determined that the reception intensity has not changed. However, taking into consideration the influence of noise, etc. generated from other electronic devices, such as changes in the radio propagation environment, Next, the difference with respect to the new reception strength is calculated (that is, “{[RSSI K (2n + 1)] − [RSSI K (2n−1)]} / [RSSI K (2n−1)]”, “{[RSSI
K (2n + 2) ′] − [RSSI K (2n) ′]} / [RSSI K (2n) ′], “{[RSSI K (2n + 2)] − [RSSI K (2n)]} / [RSSI K (2n) ]] ”,“ {[RSSI K (2n + 1) ′] − [RSSI K (2n−1) ′]} / [RSSI K (2n−1) ′] ”).

For example, if the value obtained by calculating the difference is within a range of ± 20%, it is determined that the reception intensity has not changed. If the value is outside the range of ± 20%, it is determined that the reception intensity has changed. In addition,
The condition for recognizing whether or not the reception intensity has changed is not limited to the above "20%", but takes into account the influence of noise, etc. generated from other electronic devices, such as changes in the radio propagation environment. It is preferable to set appropriately.

  If the mobile terminal device 1 determines that the reception intensity of the radio wave transmitted from the key 21 or 22 does not change and the reception intensity information in the message transmitted from the key 21 or 22 changes, Notification processing such as alarm sound is performed.

  As described above, according to the mobile terminal device and the key of the embodiment of the present invention, the mobile terminal device can be used even when an object to which a certain key is attached moves along a circle centering on the mobile terminal device. Output alarm sound. For this reason, the user of the portable terminal device can notice without omission that the object is being carried.

  According to the portable terminal device, the key, and the wireless authentication system of the present invention, even if the number of objects to which the key is attached increases, an alarm sound is output even though the object is not carried. This is advantageous in that it can be suppressed, and is useful in the field of portable terminal devices that perform wireless authentication with a plurality of keys and keys that perform wireless authentication with the portable terminal device.

Configuration diagram (example) of wireless authentication system according to an embodiment of the present invention Configuration diagram of wireless authentication system according to an embodiment of the present invention (another example) Functional block diagram of portable terminal device and key according to an embodiment of the present invention Time chart of wireless communication processing performed by portable terminal device and key of embodiment of present invention Overview of conventional anti-theft system

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Portable terminal device 11 Wireless authentication part 111 Authentication wireless control part 112 Reception intensity memory | storage part 113 Authentication control part 114 Reception intensity processing part 12 Wireless communication control part 13 Output part 14 Operation key 15 Portable terminal control part 2 Key 21, 22, 23 Key 24 Wireless Authentication Unit 241 Authentication Wireless Control Unit 242 Reception Strength Storage Unit 243 Authentication Processing Unit 244 Key Control Unit 91 Mobile Terminal Device 911, 912, 913 Key

Claims (2)

A wireless unit that performs wireless communication with the first key or the second key, a detection unit that detects reception intensity of radio waves received from the first key or the second key by the wireless unit, a notification unit, Control that causes the wireless unit to receive a message including communication information of the first key and the second key transmitted from the first key, and causes the notification unit to perform notification processing according to the communication status with a part,
The control unit changes a reception intensity of the radio wave received from the first key among a reception intensity from the first key and the second key detected by the detection unit at a predetermined time interval within a predetermined range. In addition, the reception intensity of the radio wave received from the second key does not change from the previous reception intensity, and the communication information in the message transmitted from the first key indicates that the second key is A portable terminal device that performs control to cause the notification unit to perform a notification process when the electric field strength at the time of transmission to the portable terminal device changes from the previous electric field strength . A wireless authentication system comprising the mobile terminal device according to claim 1 and a key.