JP2013210878A - Radio id authentication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a time for a sequence to acquire an ID signal.SOLUTION: A radio ID authentication system 1 uses an ID acquisition apparatus 2 for repeatedly transmitting an ID start signal for acquiring an ID at predetermined intervals, and an authentication key 3 for transmitting an ID signal synchronously with the ID start signal. When the authentication key 3 receives the ID start signal, the authentication key 3 transmits the ID signal in transmission timing frames which are individually and randomly changed in a repeated transmission period of the ID start signal. When the ID acquisition apparatus 2 normally receives the ID signal from the authentication key 3, the ID acquisition apparatus 2 transmits an ID transmission stop instruction with information about the authentication key 3. When the authentication key 3 receives the ID transmission stop instruction transmitted to the authentication key 3 from the ID acquisition apparatus 2, the authentication key 3 stops transmitting the ID signal.

Description

  The present invention provides a wireless ID using an ID acquisition machine that periodically and repeatedly transmits an ID activation signal for acquiring an ID, and an authentication key that transmits an ID signal in synchronization with the ID activation signal from the ID acquisition machine. It relates to an authentication system.

  A function in which a reader reads data of a plurality of wireless ID tags simultaneously, a so-called anti-collision function is conventionally known. FIG. 5 shows a schematic configuration of a wireless ID authentication system having an anti-collision function. In the wireless ID authentication system 51 of FIG. 5, when the ID acquisition device (reader) 52 transmits an ID activation signal (ID transmission request: arrow A in FIG. 5), the authentication key (wireless ID tag) that has received this ID activation signal. 53 transmits an ID signal (unique identification number: arrow B in FIG. 5) in synchronization with the ID activation signal. At that time, there may be a case where a large number of authentication keys 53 exist simultaneously in the communicable area (signal reachable range) of the ID activation signal from the ID acquisition machine 52. In this case, each of the plurality of authentication keys 53 reacts simultaneously to the ID activation signal from the ID acquisition device 52 and transmits an ID signal respectively.

  Here, among the plurality of authentication keys 53-1, 53-2,..., 53-n of the wireless ID authentication system 51 of FIG. When the authentication key 53-2 transmits an ID signal, interference occurs between the two, and the ID signal from the two authentication keys 53-1, 53-2 may not be correctly received by the ID acquisition device 52.

  In order to solve this problem of interference, each authentication key 53 (53-1, 53-2,..., 53-n) repeatedly transmits an ID signal for a predetermined number of transmissions. The transmission interval at which the ID signal is repeatedly transmitted is different for each authentication key 53, (2) when multiple types of transmission intervals are allocated to each authentication key 53, and (3) each authentication key 53 is randomly transmitted each time. There are cases where data is sent at intervals. For example, in the RFID tag disclosed in Patent Document 1 below, anti-collision is performed by transmitting its own ID with a predetermined time delay with respect to a call from a reader (ID acquisition machine).

JP 2011-039730 A

  However, in the conventional wireless ID authentication system 51, in order to reduce interference between the ID acquisition device 52 and the plurality of authentication keys 53, the number of transmissions of the ID signal of each authentication key 53 is increased, or the transmission interval is increased. There is a problem that the time required for the sequence required to transmit the ID activation signal from the ID acquisition device 52 and acquire the ID signals from the plurality of authentication keys 53 increases.

  Further, even if the ID acquisition unit 52 has already read the ID signal from the authentication key 53, the authentication key 53 always transmits the ID signal a predetermined number of times thereafter, so that unnecessary signal transmission / reception is repeated. End up. For this reason, when the authentication key 53 uses various batteries such as a dry battery, a button battery, and a rechargeable battery as a drive source, there is a problem that power is consumed wastefully and the battery of the authentication key 53 is consumed quickly.

  Therefore, the present invention has been made in view of the above problems, and can shorten the sequence time for acquiring the ID signal. In addition, when the authentication key uses a battery as a driving source, it is useless. It is an object of the present invention to provide a wireless ID authentication system that can suppress battery consumption without consuming electric power.

In order to achieve the above object, a wireless ID authentication system according to claim 1 includes an ID acquisition unit that repeatedly transmits an ID activation signal for acquiring an ID, and an ID signal in synchronization with the ID activation signal. In a wireless ID authentication system using an authentication key for transmitting
The authentication key, when receiving the ID activation signal, transmits an ID signal by a transmission timing frame that is randomly changed individually within the period of the repeated transmission,
When the ID acquisition machine normally receives the ID signal from the authentication key, it transmits an ID transmission stop command together with information on the authentication key,
The authentication key stops transmission of an ID signal when receiving an ID transmission stop command addressed to itself from the ID acquisition machine.

The wireless ID authentication system according to claim 2 is the wireless ID authentication system according to claim 1,
The transmission timing frame is one transmission mode determined and selected from a plurality of different transmission modes,
The plurality of transmission modes include a retransmission cycle for transmitting an ID signal in a different slot for each transmission mode,
The authentication key transmits an ID signal in a transmission timing frame according to one transmission mode selected and determined from the plurality of transmission modes when the ID activation signal is received.

The wireless ID authentication system according to claim 3 is the wireless ID authentication system according to claim 2,
The plurality of transmission modes further include an initial cycle common to each transmission mode for transmitting an ID signal in a fixed slot.

The wireless ID authentication system according to claim 4 is the wireless ID authentication system according to claim 2 or 3,
The retransmission cycle comprises a plurality of cycles;
The authentication key transmits an ID signal in a transmission timing frame that is randomly changed for each retransmission cycle.

The wireless ID authentication system according to claim 5 is the wireless ID authentication system according to any one of claims 1 to 4,
When the ID acquisition device does not detect transmission of an ID signal from the authentication key in response to the ID activation signal, the ID acquisition device skips reception in the cycle and transmits the next ID activation signal.

The wireless ID authentication system according to claim 6 is the wireless ID authentication system according to any one of claims 1 to 5,
The authentication key includes an active tag that operates using various batteries as a driving source.

The wireless ID authentication system according to claim 7 is the wireless ID authentication system according to any one of claims 2 to 6,
The authentication key divides the encrypted ID value into a plurality of blocks by several digits, and the value indicated by one block selected from the divided blocks is used as the mode number of the transmission mode. It is characterized by determining.

  According to the present invention, when there are a plurality of authentication keys at the same time in the communicable area, the authentication key for which the ID acquisition device has already acquired the ID signal is in a non-responsive state for a certain period (for example, several seconds) by a transmission stop command. Since unnecessary ID signal transmissions are reduced, the number of IDs transmitted from the authentication key is reduced, the interference rate is reduced, the sequence execution time can be saved, and the sequence time can be shortened compared to the prior art. Can do.

  Further, when an authentication key using various batteries as a drive source is used, the number of transmissions is reduced, so that power is not consumed wastefully, battery consumption of the authentication key is suppressed, and power saving can be achieved. it can.

1 is a block configuration diagram of a wireless ID authentication system according to the present invention. It is a figure which shows an example of the transmission timing frame of the radio | wireless ID authentication system which concerns on this invention. It is a figure which shows an example of the ID signal after the encryption used when determining a transmission timing frame. It is operation | movement explanatory drawing between the ID acquisition machine and authentication key in the wireless ID authentication system which concerns on this invention. It is explanatory drawing of a common wireless ID authentication system.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the present invention is not limited to this embodiment, and all other forms, examples, operational techniques, etc. that can be implemented by those skilled in the art based on this form are included in the scope of the present invention. .

  The wireless ID authentication system 1 of this example has an anti-collision function and uses an ID acquisition machine 2 and an authentication key 3 as shown in FIG. The ratio of interference when a plurality of authentication keys 3 are simultaneously present in the communicable area (signal reachable range) is reduced, and the time required for the sequence in which the ID acquisition device 2 acquires ID signals from the plurality of authentication keys 3 is shortened. I am trying. Further, when the authentication key 3 is battery driven, wasteful power consumption is suppressed, battery consumption is reduced, and power saving is achieved.

  In addition, the wireless ID authentication system 1 of this example includes, for example, apartment houses such as condominiums, commercial office buildings, public facilities, elevator halls in large facilities such as hotels, entrance / exit gates to specific areas partitioned in the floor, guest rooms, Installed in tenants, lockers, etc. Moreover, in the following description, the process between the ID activation signal that is repeatedly transmitted by the ID acquisition machine 2 at a predetermined cycle and the next ID activation signal are defined as one sequence.

  The ID acquisition device 2 is configured by a reader / writer device that acquires an ID signal from the authentication key 3 through wireless communication with the authentication key 3, and includes various types of power sources such as a commercial power supply (AC100V), a dry battery, a button battery, and a rechargeable battery. As shown in FIG. 1, a battery is used as a drive source, and a wireless communication unit 2a, a storage unit 2b, and a control unit 2c are provided.

  The wireless communication unit 2a performs wireless communication with one or a plurality of authentication keys 3 existing in the communicable area under the control of the control unit 2c, and the authentication key 3 existing in the communicable area. An ID activation signal (ID transmission request: arrow A in FIG. 1) for acquiring an ID signal is repeatedly transmitted at a predetermined cycle (polling).

  In addition, the wireless communication unit 2a receives the encrypted ID signal transmitted from the authentication key 3 in the communicable area with the transmission of the ID activation signal.

  Further, the wireless communication unit 2a checks the validity of the ID signal when the ID signal is normally received from the authentication key 3, that is, when an ID signal exceeding a certain reception level value is received, and / or by detecting a code error. When the result is normal, the ID signal received (or information identifying the authentication key 3 that transmitted the ID signal) is specified so that the transmission of the ID signal from the authentication key 3 is stopped for a certain period (for example, several seconds). ) Together with an ID transmission stop command.

  The storage unit 2b is composed of, for example, a magnetic or optical storage medium or a semiconductor memory such as a ROM or a RAM. The storage unit 2b receives a reference reception level value for determining whether or not the level of the ID signal received from the authentication key 3 exceeds a certain value, and a code for decoding the ID signal received from the authentication key 3 ( Rolling code, challenge data, etc.), ID value for verifying the decrypted ID signal (whether use of the wireless ID authentication system 1 is permitted), necessary for authenticating the ID signal such as the reception time limit Various kinds of information are stored.

  The control unit 2c controls the wireless communication unit 2a so as to repeatedly transmit (polling) the ID activation signal at a predetermined cycle.

  Further, in each sequence, the control unit 2c, when the wireless communication unit 2a normally receives the ID signal from the authentication key 3, together with the received ID signal (or information specifying the authentication key 3 that transmitted the ID signal). The wireless communication unit 2a is controlled to transmit an ID transmission stop command.

  Furthermore, in order to save sequence execution time in each sequence, the control unit 2c determines that the wireless communication unit 2a does not detect transmission of the ID signal from the authentication key 3 in response to the ID activation signal (for example, the wireless communication unit). When the level of the received signal by 2a is compared with the received level value stored in the storage unit 2b and it is determined that no received signal exceeding the received level value is detected, the wireless communication unit 2a is within a predetermined reception limit time. When the ID signal from the authentication key 3 is not received), the wireless communication unit 2a is controlled so as to skip the repetition of the reception cycle in the sequence and round it up to transmit the next ID activation signal.

  The authentication key 3 (3-1, 3-2,..., 3-n) is owned by each user of the wireless ID authentication system 1, and is a short-range wireless communication (communication distance) using an electromagnetic field or a radio wave. : RFID tags (Radio Frequency Identification Tags) consisting of a CPU, ROM, RAM, flash RAM, etc. that can be several centimeters to several meters), or various media (for example, card-like storage media and mobile phones) Including smartphones).

  As shown in FIG. 1, the authentication key 3 includes a wireless communication unit 3a, a storage unit 3b, and a control unit 3c. In the case where the wireless ID tag is used as the authentication key 3, a passive tab that operates using radio waves from the ID acquisition device 2 as an energy source, for example, an active that operates using various batteries such as a dry battery, a button battery, and a rechargeable battery as a driving source. A semi-active tag is used which has a function of an active tag with a built-in tag and battery, but starts communication in a host system in a passive manner.

  When the authentication key 3 exists in the communicable area and the wireless communication unit 3a receives an ID activation signal from the ID acquisition device 2, the wireless communication unit 3a synchronizes with the ID activation signal to transmit a transmission timing frame (transmission mode) described later. ) Transmits an ID signal (arrow B in FIG. 1).

  Further, the wireless communication unit 3a receives an ID transmission stop command transmitted from the ID acquisition device 2 when the authentication key 3 exists in the communicable area. If the received ID transmission stop command is addressed to itself, the wireless communication unit 3a ignores the activation signal from the ID acquisition unit 2 and stops transmitting the ID signal for a certain period thereafter (for example, several seconds). ing.

  Further, when the wireless communication unit 3a transmits the ID signal again after a certain period of time has elapsed from the state where the transmission of the ID signal is stopped, the wireless communication unit 3a will be described later in the first sequence in which the ID activation signal is received from the ID acquisition device 2. The ID signal is transmitted in the transmission timing frame of the transmission mode determined by the method, or the transmission timing frame of the previous transmission mode (stored in the storage unit 3b) selected immediately before stopping the transmission of the ID signal.

  The storage unit 3b is composed of, for example, a magnetic or optical storage medium or a semiconductor memory such as a ROM or a RAM. The storage unit 3b has its own ID value (information for identifying the authentication key 3, such as individual identification information such as a manufacturing number), the previous transmission mode selected immediately before stopping the transmission of the ID signal, and will be described later in one sequence. The upper limit value of the number of retransmissions in the retransmission cycle in the transmission timing frame is stored. The upper limit value of the number of retransmissions can be set as the same number or a different number for each sequence.

  When the wireless communication unit 3a receives an ID activation signal from the ID acquisition device 2, the control unit 3c transmits an ID signal in a transmission timing frame (any of transmission modes 1 to n) determined by a method described later. Therefore, the wireless communication unit 3a is controlled.

  When the control unit 3c transmits the ID signal again from the state where the transmission of the ID signal is stopped, the control unit 3c transmits the transmission timing frame of the transmission mode determined by the method described later or the previous transmission mode stored in the storage unit 3b. The wireless communication unit 3a is controlled to transmit the ID signal within the transmission timing frame.

  In addition, when the wireless communication unit 3b receives the ID signal and the ID transmission stop command from the ID acquisition unit 2, the control unit 3c determines whether the ID signal and the ID transmission stop command are addressed to itself. When it is determined that it is addressed to itself, the wireless communication unit 3b is controlled to stop the transmission of the ID signal by ignoring the activation signal from the ID acquisition device 2 for a certain period thereafter (for example, several seconds). .

  Here, the transmission timing frame of the ID signal that each authentication key 3 transmits in synchronization with the ID activation signal from the ID acquisition device 2 will be described. The transmission timing frame is determined by selecting any one transmission mode from among a plurality of transmission modes 1 to n (n is a natural number).

  Hereinafter, a case where one transmission mode is selected from the four transmission modes 1 to 4 will be described as an example. As shown in FIG. 2, each of the four transmission modes 1 to 4 includes an initial cycle c1 and two retransmission cycles c2 (c2a, c2b).

  The initial cycle c1 is a cycle in which an ID signal is transmitted in a fixed initial slot, and is common to the transmission modes 1 to 4.

  The retransmission cycle c2 is a cycle in which the ID signal is transmitted in slots (slots 1 to 4) having different periods for the respective transmission modes 1 to 4.

  Specifically, in the example of FIG. 2, retransmission cycles c2a and c2b in transmission mode 1 are slot 1, retransmission cycles c2a and c2b in transmission mode 2 are slots 2, and retransmission cycles c2a and c2b in transmission mode 3 are slots. 3. Retransmission cycles c2a and c2b in transmission mode 4 transmit ID signals in slot 4 respectively.

  In the example of FIG. 2, two retransmission cycles c2 are illustrated, but the number is not limited to two, and may be one or three or more.

  Then, when determining the transmission timing frame, for example, an encrypted ID value is used as a random value in order to give different properties for each random ID and ID, and each authentication key 3 is used when transmitting an ID signal. The transmission timing frame to be changed is randomly changed for each retransmission cycle c2a, c2b.

  Specifically, a case where the ID value after encryption of the ID signal is 32 bits and the plurality of transmission modes 1 to n are four (n = 4) will be described as an example.

  In this case, as shown in FIG. 3, the 32-bit encrypted ID value is converted into 16 block blocks 1 to 16 (block number) each having 2 bits as a bit value unit indicating the mode numbers 1 to 4 of the transmission modes 1 to 4. 1 to 16), and the value (any one of 00, 01, 10, and 11) indicated by 2 bits, which is each bit value unit of the 16 divided blocks Block 1 to 16, is the mode number of the transmission modes 1 to 4. Assign to 1-4 respectively.

  For example, “00” is transmission mode 1 (mode number 1), “01” is transmission mode 2 (mode number 2), “10” is transmission mode 3 (mode number 3), and “11” is transmission mode 4 (mode number). 4).

  Then, for each retransmission cycle c2 (c2a, c2b) in one sequence, one block is selected randomly or regularly from the 16 blocks Blocks 1 to 16, and the transmission mode is determined. For example, with respect to the retransmission cycle c2b in one sequence of FIG. 2, when one randomly selected block is the block Block 3, the transmission mode 1 indicated by the 2-bit value “00” of the block Block 3 of FIG. It is determined as a transmission timing frame.

  When one block is regularly selected from the 16 blocks Block 1 to 16, for example, the block Block 1 on the least significant bit side is selected from the 16 blocks Block 1 to 16, and is retransmitted ( One block is selected by incrementing the block number used for each retransmission cycle c2a, c2b). Also, the block number 16 selected from the most significant bit block 16 among the 16 blocks Block 1 to 16 is selected, and one block is selected by decrementing the block number used for each retransmission (retransmission cycle c2a, c2b). May be.

  In this way, the ID value after encryption is divided into a plurality of blocks according to the number of selectable transmission modes 1 to n, the bit value of each block is referred to as the mode number of the transmission mode, A transmission timing frame is determined by selecting a transmission mode. Further, within one sequence, the transmission timing is made random by changing the block to be referenced each time retransmission is performed.

  The authentication key 3 receives any of the transmission modes 1 to n determined by the above-described method when receiving the ID activation signal from the ID acquisition device 2 (in the example of FIG. 2, any of the transmission modes 1 to 4). The ID signal is transmitted within the transmission timing frame. Further, the transmission mode is changed every time retransmission is performed, and the ID signal is transmitted in the transmission timing frame according to the changed transmission mode.

  When determining the transmission timing frame, the greater the number of transmission modes and the greater the number of retransmission cycles, the lower the possibility of collision within one transmission (one sequence), but the sequence is completed. Will increase the execution time. For this reason, it is preferable to set the number of transmission modes and the number of retransmission cycles in consideration of implementation.

  Further, although the randomness of the transmission timing is reduced, the transmission mode of each authentication key 3 may be changed for each sequence. In this case, when an ID activation signal is received from the ID acquisition device 2, transmission modes within one sequence can be determined collectively.

  As described above, if the encrypted ID value is used to determine the transmission timing frame, it is possible to prevent leakage of ID information due to analysis of the transmission timing. In addition, if ID code encryption is used in combination with a rolling code method, challenge / response method, etc., the ID value itself after encryption changes, which is disadvantageous in that there are many overlapping transmission timings with other authentication keys 3. It is possible to prevent the condition from being repeated with the specific authentication key 3.

  Next, the operation of the wireless ID authentication system 1 configured as described above will be described with reference to FIG.

  ST1: The ID acquisition device 2 repeatedly transmits an ID activation signal for acquiring an ID signal from a plurality of authentication keys 3 existing in the communicable area at a predetermined period (polling).

  ST2: Each of the plurality of authentication keys 3 existing in the communicable area receives the ID activation signal from the ID acquisition device 2, and determines the transmission timing frame by the method described above. Specifically, one of the four transmission modes 1 to 4 in FIG. 2 is selected to determine a transmission timing frame. The transmission mode is changed for each retransmission cycle c21 and c2b or for each sequence.

  ST3: The plurality of authentication keys 3 existing in the communicable area transmit ID signals in the determined transmission timing frames. Specifically, when the transmission mode 2 is selected in the first retransmission cycle c2a by the above-described transmission timing frame determination method with a certain authentication key 3, as shown in FIG. 2, in the initial slot of the initial cycle c1. After transmitting the ID signal, the ID signal is transmitted in slot 2 of the retransmission cycle c2a. Subsequently, when the transmission mode 4 is selected in the retransmission cycle c2b, the ID signal is transmitted in the slot 4 of the retransmission cycle c2b.

  Similarly, in the other authentication keys 3, one transmission mode is selected from a plurality of transmission modes 1 to n for each retransmission cycle or for each sequence by the transmission timing frame determination method described above. To determine the transmission timing frame.

  ST4: The ID acquisition unit 2 determines whether or not the ID signal is transmitted from the authentication key 3 accompanying the transmission of the ID activation signal, the reception level determination of the ID signal from the authentication key 3, and the ID value determination (code error detection, correctness). Discrimination). That is, when receiving the ID signal from the authentication key 3, the ID acquisition device 2 determines whether or not the level of the received ID signal exceeds the reception level value of the storage unit 2b. When the ID acquisition device 2 determines that the level of the ID signal received from the authentication key 3 has been received normally exceeding the reception level value, the ID acquisition device 2 recognizes that there is transmission of the ID signal from the authentication key 3 and receives the signal. As the ID value discrimination of the ID signal, the code error detection and the legitimacy discrimination are performed.

  When the ID acquisition unit 2 determines in each sequence that there is no transmission of the ID signal from the authentication key 3 accompanying the transmission of the ID activation signal (for example, the level of the signal received by the wireless communication unit 2a and the storage in the storage unit 2b). When the wireless communication unit 2a does not receive an ID signal from the authentication key 3 within a predetermined reception time limit when it is determined that a reception signal exceeding the reception level value is not detected by comparing with the received reception level value Etc.), the repetition of the reception cycle in the sequence is skipped and rounded up, and the next ID activation signal is transmitted.

  ST5, ST6: When the ID error detection of the received ID signal is normally performed and the ID value is normally authenticated, the ID acquisition device 2 identifies the normally authenticated ID signal (or the authentication key 3 that transmitted the ID signal). Information) and an ID transmission stop command are transmitted in the next slot.

  For example, when the ID signal transmitted from the authentication key 3 in the slot 2 of the retransmission cycle c2b in the transmission mode 2 is received, the code error detection of the ID signal is normally performed, and the normal authentication is performed when the ID value is normally authenticated. An ID transmission stop command is transmitted at the timing of the next slot 3 together with the ID signal (or information specifying the authentication key 3 that transmitted the ID signal).

  ST7: When the authentication key 3 receives the ID signal and the ID transmission stop command from the ID acquisition device 2, it determines whether the ID signal and the ID transmission stop command are addressed to itself, and determines that it is addressed to itself. Then, for a certain period thereafter (for example, several seconds), the activation signal from the ID acquisition device 2 is ignored, and the transmission of the ID signal is temporarily stopped. The transmission mode of the previous transmission timing frame selected immediately before the ID transmission is stopped is stored in the storage unit 3b.

  Then, the authentication key 3 that has stopped transmitting the ID signal has a transmission mode transmission timing frame determined by the above-described method in the first sequence in which the ID activation signal is received from the ID acquisition device 2 after a certain period of time has elapsed. Alternatively, the ID signal is transmitted again in the transmission timing frame of the previous transmission mode stored in the storage unit 3b, and thereafter, the above-described operation is executed.

  As described above, in the wireless ID authentication system 1 of the present example, transmission of unnecessary ID signals is reduced by the transmission stop command for the authentication key 3 for which the ID acquisition device 2 has already acquired the ID signal. That is, the authentication key 3 that has received the transmission stop command is in a non-responsive state for a certain period (for example, several seconds). As a result, when there are a plurality of authentication keys 3 at the same time within the communicable area (signal reachable range) of the ID activation signal from the ID acquisition device 2, the number of IDs transmitted from the authentication key 3 decreases, so It is expected that the signal collision will be effectively eliminated.

  When the signal collision is resolved, all the authentication keys 3 in the communicable area are already read by the ID acquisition unit 2 and are temporarily stopped in transmission, so that the ID signal is transmitted through one cycle. If it is not detected, it is possible to shift to the next sequence, save the sequence execution time, and shorten the sequence time as compared with the prior art.

  There are rare cases where signal collisions are not resolved over a long period of time. For this reason, in this example, an upper limit value of the number of retransmissions is provided for each authentication key 3. Thereby, even if a signal collision remains, the transmission of the ID signal can be stopped once and the next sequence can be performed. At this time, the state of the authentication key 3 (block number reference counter, transmission stop state) is reset.

  Even when the authentication key 3 using various batteries as a drive source is used, as described above, the number of transmissions is reduced and congestion of wireless use is alleviated. Therefore, battery consumption of the authentication key 3 can be suppressed, and power saving can be achieved.

  Furthermore, when each authentication key 3 determines a transmission timing frame, if the code (rolling code, challenge data, etc.) used for encryption is changed, the encrypted ID is also changed accordingly, and the transmission timing is also changed. Since the allocation status of each transmission mode of the frame changes completely, it is possible to avoid the same status being repeated.

  Incidentally, in the above-described embodiment, it has been described that one sequence includes the initial cycle c1 and the retransmission cycle c2 (two retransmission cycles c2a and c2b in the example of FIG. 2). Since it is not particularly necessary from the viewpoint of avoidance, it can be omitted.

  However, when there is no authentication key 3 in the communicable area or only one authentication key 3 is considered, it is preferable to provide an initial cycle c1 in the sequence in order to emphasize the response in that case. . In this initial cycle c1, all the authentication keys 3 transmit the ID signal. Therefore, if there is no authentication key 3 in the communicable area, only the initial cycle c1 is performed and the authentication key 3 is in the communicable area. 3 can be discriminated on the ID acquisition machine 2 side, and a transition to the next sequence can be made. As a result, the response when the authentication key 3 enters the communicable area can be improved.

DESCRIPTION OF SYMBOLS 1 Wireless ID authentication system 2 ID acquisition machine 2a Wireless communication part 2b Storage part 2c Control part 3 Authentication key 3a Wireless communication part 3b Storage part 3c Control part

Claims (7)

In a wireless ID authentication system using an ID acquisition machine that repeatedly transmits an ID activation signal for acquiring an ID and an authentication key that transmits an ID signal in synchronization with the ID activation signal,
The authentication key, when receiving the ID activation signal, transmits an ID signal by a transmission timing frame that is randomly changed individually within the period of the repeated transmission,
When the ID acquisition machine normally receives the ID signal from the authentication key, it transmits an ID transmission stop command together with information on the authentication key,
The wireless authentication system according to claim 1, wherein the authentication key stops transmission of an ID signal when receiving an ID transmission stop command addressed to itself from the ID acquisition machine. The transmission timing frame is one transmission mode determined and selected from a plurality of different transmission modes,
The plurality of transmission modes include a retransmission cycle for transmitting an ID signal in a different slot for each transmission mode,
The authentication key transmits an ID signal in a transmission timing frame according to one transmission mode selected and determined from the plurality of transmission modes when the ID activation signal is received. The wireless ID authentication system according to 1. The wireless ID authentication system according to claim 2, wherein the plurality of transmission modes further include an initial cycle common to each transmission mode in which an ID signal is transmitted in a fixed slot. The retransmission cycle comprises a plurality of cycles;
4. The wireless ID authentication system according to claim 2, wherein the authentication key transmits an ID signal in a transmission timing frame that is randomly changed for each retransmission cycle. 5. 2. The ID acquisition device according to claim 1, wherein when the transmission of the ID signal from the authentication key in response to the ID activation signal is not detected, reception of the ID activation signal is skipped and the next ID activation signal is transmitted. The wireless ID authentication system in any one of -4. 6. The wireless ID authentication system according to claim 1, wherein the authentication key includes an active tag that operates using various batteries as a driving source. The authentication key divides the encrypted ID value into a plurality of blocks by several digits, and the value indicated by one block selected from the divided blocks is used as the mode number of the transmission mode. The wireless ID authentication system according to claim 2, wherein the wireless ID authentication system is determined.

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