JP3893802B2 - Mobile object identification system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mobile object identification system including an interrogator and a responder.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a moving body identification system using a non-contact IC card system described in JP-A-8-123919 is known.
[0003]
FIG. 6 shows a communication method of a conventional non-contact IC card system. In this system, for example, when a plurality of cards 601a, 601b, and 601c enter the communication area, the read / write device 602 can access the cards 601a, 601b, and 601c in the communication area, and the cards 601a, 601b, and 601c. Determines the timing for returning the response block 604 including the ID code from the first condition 603 indicated by the read / write device 602 and its own ID code, and the response sent by the cards 601a, 601b, 601c to the read / write device 602. A block 604 is received, a data collision is detected, a condition is changed based on the result, and a resend request 605 for a response block including an ID code is made.
[0004]
For example, the card 601a retransmits the response block 606 after TO from the retransmission request, and the other cards 601b and 601c retransmit the response block 606 after TO + T (ID). The read / write device 602 processes the response block 606a from the card 601a that has not collided. Further, a resend request 607 is made, and the card 601b resends the response block 608 after TO from the resend request and the other card 601c resembles TO + T (ID). By repeating this, a response block is received from the card 601 without collision, and communication with a plurality of cards is performed.
[0005]
[Problems to be solved by the invention]
This mobile object identification system is required to be small and inexpensive and to read information from a plurality of responders in the same area in a short time.
[0006]
It is an object of the present invention to configure a system that can read information from a plurality of responders in the same area in a short time with a small size and low cost.
[0007]
[Means for Solving the Problems]
In order to solve this problem, the present invention comprises a plurality of stepwise modulators on the responder side, and is configured to change the communication quality according to the communication conditions.
[0008]
Thereby, it is possible to configure a mobile object identification system that is small and inexpensive and can read data of a plurality of responders in the same area in a short time.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The invention according to claim 1 of the present invention includes a signal source that generates an output signal, a modulation unit that modulates an output signal from the signal source, an antenna that transmits an output signal modulated by the modulation unit, and the antenna A demultiplexer for demultiplexing a reflected wave as a response signal received from the output signal, a demodulator for demodulating the response signal, a data processor for processing a signal from the demodulator, and data of the processor An interrogator having a control unit for controlling the interrogator, and a responder antenna for receiving a signal transmitted from the interrogator and transmitting a reflected wave as the response signal to the antenna of the interrogator A demodulator that demodulates the received input signal; Every demodulation A control unit for outputting a control signal for controlling a modulation degree of an input signal used for the response signal, and using the control signal, Every demodulation In addition, the input signal used for the response signal is amplitude-modulated by controlling a switch that switches the two absorbers having different combinations from the first, second, and third absorbers that are amplitude-modulated by different absorption amounts. And a transponder having a modulation section that outputs the response signal.
[0010]
As a result, the transponder amplitude-modulates the signal from the interrogator using absorbers with different absorption amounts, so that waves with different degrees of modulation are reflected as response signals for each transponder, and the interrogator has a plurality of transponders. By separating the response signals from each other according to the difference in modulation degree, it is possible to simultaneously demodulate the response signals from each responder. It has the effect that it can be read.
[0011]
Furthermore, The responder selects an arbitrary modulation factor, so that a wave with a different modulation factor is reflected as a response signal at each communication, and the interrogator separates response signals from multiple responders according to the difference in the modulation factor. By making it possible to simultaneously demodulate the response signals from the responders, there is an effect that the data of a plurality of responders in the same area can be read in a short time with a small size and low cost.
[0012]
Claim 2 The invention according to claim 1 is the mobile unit identification system according to claim 1, in the first time. Demodulated signal Is The above By switching the first and second absorbers, Above From the interrogator input Signal , Amplitude modulation to reflected wave as response signal Demodulated signal Is Above Amplitude modulation by switching the first and third absorbers Rumo The response of the responder that the interrogator failed to read the data in the first communication by switching the modulation degree during the first communication and the modulation degree during the second and subsequent communication. By separating and demodulating the signal according to the difference in modulation degree, it has the effect of being small and inexpensive and capable of reading data from a plurality of responders in the same area in a short time.
[0013]
Claim 3 In the mobile object identification system according to claim 1, Above The absorption amount of the first absorber is 0 dB, Above The absorption amount of the second absorber is 10 dB, Above The absorption amount of the third absorber is 20 dB. Rumo The interrogator separates the response signals from multiple responders by the difference in the degree of modulation by performing amplitude modulation with a large degree of modulation and amplitude modulation with a small degree of modulation. By making it possible to simultaneously demodulate the response signals, there is an effect that the data of a plurality of responders in the same area can be read in a short time with a small size and low cost.
[0014]
Claim 4 In the mobile object identification system according to claim 1, Above The response signal of the transponder is , It consists of a data string that includes a solid recognition data string and an information data string. Above By switching the first and third absorbers, Above From the interrogator input The signal is amplitude-modulated to a reflected wave as a response signal. Above Amplitude modulation by switching the first and second absorbers Rumo Even if the solid recognition data sequence and the information data sequence are simultaneously transmitted from a plurality of responders, the responder switches between the modulation factor at the time of transmitting the solid recognition data sequence and the modulation factor at the time of transmission of the information data sequence. The interrogator can separate the response signals according to the difference in modulation degree and simultaneously demodulate them, so that the data of multiple responders in the same area can be read in a short time with a small size and low cost. Have
[0015]
The invention according to claim 5 is a signal source that generates an output signal, a modulation unit that modulates an output signal from the signal source, an antenna that transmits an output signal modulated by the modulation unit, and an antenna that is received by the antenna. A demultiplexer for demultiplexing the reflected wave as the response signal from the output signal, a demodulator for demodulating the response signal, a data processor for processing the signal from the demodulator, and an interrogator based on the data of the processor An interrogator having a control unit for controlling the interrogator, a signal transmitted from the interrogator, an antenna for a responder that transmits a response signal to the antenna of the interrogator, and a demodulator of the received input signal Depending on the number of communications with the demodulator and the interrogator, the demodulator Every demodulation A control unit that outputs a control signal for controlling the modulation degree of the input signal used for the response signal, and first, second, and third phase shifters that perform phase modulation with different phase amounts using the control signal. Depending on the number of times of communication with the interrogator, the demodulator Every demodulation And a modulator that controls a switch that switches between the two phase shifters having different combinations, phase-modulates an input signal used for the response signal, and outputs the response signal as the response signal; , Including a mobile object identification system.
[0016]
As a result, the transponder phase-modulates the signal from the interrogator using phase shifters with different phase amounts, so that waves with different degrees of modulation are reflected as response signals for each transponder, and the interrogator has multiple responses. By separating the response signals from the transponders according to the difference in the modulation degree and demodulating the response signals from each transponder at the same time, the data of multiple transponders in the same area can be reduced in a short time. It has the effect that it can be read by.
[0017]
Furthermore, When the transponder selects an arbitrary modulation factor, waves with different modulation factors are reflected as response signals at each communication, and the interrogator separates response signals from multiple responders according to the difference in modulation factor. By making it possible to simultaneously demodulate the response signals from the transponders, there is an effect that the data of a plurality of transponders in the same area can be read in a short time with a small size and low cost.
[0018]
Claim 6 The invention according to claim 1 is the mobile object identification system according to claim 6, wherein the first time Demodulated signal Is The above By switching the first and second phase shifters, Above From the interrogator input Signal , Phase-modulate the reflected wave as a response signal. Demodulated signal Is Above Phase modulation by switching the first and third phase shifters Rumo The response of the responder that the interrogator failed to read the data in the first communication by switching the modulation degree during the first communication and the modulation degree during the second and subsequent communication. By separating and demodulating the signal according to the difference in modulation degree, it has the effect of being small and inexpensive and capable of reading data from a plurality of responders in the same area in a short time.
[0019]
Claim 7 The invention according to claim 6 is the mobile object identification system according to claim 6, Above The phase amount of the first phase shifter is 0 degree, Above The phase amount of the second phase shifter is 170 degrees, Above The phase amount of the third phase shifter is 180 degrees. Rumo The interrogator separates the response signals from multiple responders by the difference in the degree of modulation by performing phase modulation with a large degree of modulation and phase modulation with a small degree of modulation. By making it possible to simultaneously demodulate the response signals, there is an effect that the data of a plurality of responders in the same area can be read in a short time with a small size and low cost.
[0020]
Claim 8 The invention according to claim 6 is the mobile object identification system according to claim 6, Above The response signal of the transponder is , Consists of a data string including a solid recognition data string and an information data string, and by switching the first and third phase shifters when transmitting the solid recognition data string, Above The signal from the interrogator is phase-modulated to the reflected wave as the response signal, Above Phase modulation by switching the first and second phase shifters Rumo Even if the solid recognition data sequence and the information data sequence are simultaneously sent from a plurality of responders, the responder switches between the modulation factor at the time of transmission of the solid recognition data sequence and the modulation factor at the time of transmission of the information data sequence. The interrogator can separate the response signals according to the difference in modulation degree and simultaneously demodulate them, so that the data of multiple responders in the same area can be read in a short time with a small size and low cost. Have
[0021]
The invention according to claim 9 is a signal source that generates an output signal, a modulation unit that modulates an output signal from the signal source, an antenna that transmits an output signal modulated by the modulation unit, and an antenna that is received by the antenna. A demultiplexer for demultiplexing the reflected wave as the response signal from the output signal, a demodulator for demodulating the response signal, a data processor for processing the signal from the demodulator, and an interrogator based on the data of the processor An interrogator having a control unit for controlling the interrogator, a signal transmitted from the interrogator, an antenna for a responder that transmits a response signal to the antenna of the interrogator, and a demodulator of the received input signal Depending on the number of communications with the demodulator and the interrogator, the demodulator Every demodulation In addition, a control unit that outputs a control signal for controlling the modulation degree and reflection amount of the input signal used for the response signal, an attenuator that outputs an attenuation signal with a different attenuation amount, and phase-modulating the attenuation signal with a different phase amount Different combinations of the first, second, and third phase shifters, and the attenuated signal and the phase shifter, depending on the number of communications with the interrogator. Every demodulation And a switching unit that controls the phase using the control signal, phase-modulates and outputs the response signal as a response signal. .
[0022]
As a result, the responder responds to waves with different reflection amounts and modulation factors for each responder by phase-modulating the signal from the interrogator using an attenuator with different attenuation and a phase shifter with different phase. Reflected as a signal, the interrogator separates the response signals from multiple responders according to the difference in reflection amount and degree of modulation, and allows the response signals from each responder to be demodulated simultaneously, making it compact and inexpensive Thus, the data of a plurality of responders in the same area can be read in a short time.
[0023]
Furthermore, The responder selects an arbitrary modulation factor, so that each time communication is performed, waves with different modulation factors are reflected as response signals, and the interrogator separates response signals from multiple responders according to the difference in modulation factor. By making it possible to simultaneously demodulate the response signals from the responders, there is an effect that the data of a plurality of responders in the same area can be read in a short time with a small size and low cost.
[0024]
Furthermore, The transponder selects an arbitrary amount of attenuation and modulation degree, so that a wave having a different reflection amount and modulation degree is reflected as a response signal at every communication, and the interrogator receives response signals from a plurality of transponders as signal strength and Separating according to the difference in modulation degree and allowing the response signals from each responder to be demodulated at the same time, the data of multiple responders in the same area can be read in a short time with a small size and low cost. Has an effect.
[0025]
Claim 10 The invention described in claim 9 In the mobile object identification system described in 1), the first time Demodulated signal Is Above From the interrogator input Attenuate the signal with an attenuator, Above By switching the first and second phase shifters, phase modulation is performed on the reflected wave as the response signal, and the second time Demodulated signal Is The above Without using an attenuator Above Phase modulation is performed by switching the first and second phase shifters, and the third time Demodulated signal Is The above Without using an attenuator Above Phase modulation by switching the first and third phase shifters Rumo Because the transponder switches between the amount of reflection and the modulation factor during communication, the interrogator separates and demodulates the response signal of the transponder that failed to read the data according to the difference in the modulation factor. The data of a plurality of responders in the same area can be read in a short time.
[0026]
Claim 11 The invention described in claim 9 In the mobile object identification system described in Above The phase amount of the first phase shifter is 0 degree, Above The phase amount of the second phase shifter is 170 degrees, Above The phase amount of the third phase shifter is 180 degrees. Rumo The interrogator separates the response signals from multiple responders by the difference in the degree of modulation by performing phase modulation with a large degree of modulation and phase modulation with a small degree of modulation. By making it possible to simultaneously demodulate the response signals, there is an effect that the data of a plurality of responders in the same area can be read in a short time with a small size and low cost.
[0027]
Claim 1 2 The invention described in claim 9 In the mobile object identification system described in Above Attenuator attenuation is 10 dB Rumo Because the responder uses reflected waves with different reflection amounts as response signals, the interrogator separates the response signals from multiple responders by the difference in modulation degree, and simultaneously demodulates the response signals from each responder This makes it possible to read the data of a plurality of responders in the same area in a short time with a small size and low cost.
[0028]
Claim 13 The invention described in claim 9 In the mobile object identification system described in Above The response signal of the transponder is , Solid recognition data sequence and information data sequence When Is included, and when sending a solid recognition data string Above Without using an attenuator Above By switching the first and third phase shifters, phase modulation is performed on the reflected wave as a response signal, and at the time of information data string transmission Above Attenuate with an attenuator Above Phase modulation by switching the first and third phase shifters Rumo Even if a solid recognition data sequence and an information data sequence are simultaneously sent from a plurality of responders, the responder switches the modulation degree at the time of transmission of the solid recognition data sequence and the reflection amount at the time of transmission of the information data sequence. The interrogator can separate the response signals according to the difference in the amount of reflection and simultaneously demodulate them, making it possible to read the data of multiple responders in the same area in a short time with a small size and low cost. Have
[0029]
Claim 14 The invention described in claim 9 In the mobile object identification system described in Above The response signal of the transponder is , Solid recognition data sequence and information data sequence When When the first solid recognition data string is sent Above The signal from the interrogator Above Attenuate with an attenuator Above By switching the first and third phase shifters, phase modulation is performed on the reflected wave as a response signal, and at the time of the first information data string transmission Above The signal from the interrogator Above Attenuate with an attenuator Above Phase modulation is performed by switching the first and second phase shifters, and when the second and subsequent solid recognition data strings are transmitted. Above Without using an attenuator Above By switching the first and third phase shifters, phase modulation is performed on the reflected wave as a response signal, and when the information data string is transmitted for the second and subsequent times. Above Without using an attenuator Above Phase modulation by switching the first and second phase shifters Rumo The response of the transponder that the interrogator failed to read data in the first communication by switching the modulation degree during the first communication and the modulation degree during the second and subsequent communication by the transponder. By separating and demodulating the signal according to the difference in modulation degree, it has the effect of being small and inexpensive and capable of reading data from a plurality of responders in the same area in a short time.
[0030]
Claim 15 The invention described in claim 1, 5 and 9 The moving body identification system according to any one of In the above Recognize transmission stop command from interrogator, Above Stop transmission of response signal from transponder Rumo The transponder that has completed communication receives the transmission stop command from the interrogator and stops transmitting the response signal, thereby reducing the number of responders that the interrogator communicates at the same time, and separating and demodulating the response signal. This makes it easy to read data from a plurality of transponders in the same area in a short time with a small size and low cost.
[0031]
Claim 16 The invention described in claim 1, 5 and 9 An interrogator having an antenna that transmits an output signal to any of the above, a reception antenna that receives a response signal, and a responder that communicates with the interrogator. Rumo By separating the transmission antenna and the reception antenna, the interrogator separates and demodulates the response signal to reduce interference caused by the transmission signal, thereby reducing the size and cost of multiple responders in the same area. The data can be read in a short time.
[0032]
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[0033]
(Embodiment 1)
FIG. 1 is a block diagram of a mobile unit identification system according to Embodiment 1 of the present invention, and there are two responders 103a and 103b for one interrogator 102. FIG. In FIG. 1, an interrogator-side antenna 101 and a responder-side antenna 104 function as an antenna for microwave communication between the interrogator 102 and the responder 103, and are composed of, for example, a single or a plurality of patch antennas. Yes.
[0034]
The microwave signal generated by the signal source 105 of the interrogator 102 is modulated by the modulation unit 115 and then distributed to the transmission side and the reception side by the distribution circuit 106. The signal on the transmission side passes through the demultiplexer 107 and is interrogated. It is transmitted from the side antenna 101.
[0035]
The transmitted microwave signal is received by the responder side antenna 104 of the responders 103a and 103b, and is ASK-modulated by changing the reflectance by the ASK modulator 109 according to the control signal emitted from the controller 108. It is transmitted from the side antenna 104 to the interrogator 102.
[0036]
The ASK modulation unit 109 includes a reflection condition switching unit 113, a 0 dB absorber 112a, a 10 dB absorber 112b, and a 20 dB absorber 112c. Based on the random number generated by the random number generation unit 117 by the control unit 108 during each communication. ASK modulation is performed by selecting and switching two arbitrary absorbers.
[0037]
The ASK-modulated microwaves transmitted from the responders 103a and 103b are received by the interrogator antenna 101, distributed to the receiver by the duplexer 107, demodulated by the reception demodulator 110, and processed by the data processor 111. Data from the responders 103a and 103b is read.
[0038]
As described above, each of the responders 103a and 103b performs amplitude modulation on the signal from the interrogator 102 using an arbitrary absorber having a different absorption amount every time communication is performed, so that the response from each of the responders 103a and 103b. The signal has a different degree of modulation for each communication, and the interrogator 102 separates the response signals from the plurality of responders 103a and 103b according to the difference in the degree of modulation, and simultaneously demodulates the response signals from the responders 103a and 103b. This enables the interrogator 102 to read the data of the plurality of responders 103a and 103b in a short time even if the plurality of responders 103a and 103b in the communication area simultaneously transmit response signals. A body identification system can be realized.
[0039]
In the above description, the absorbers 112a, 112b, and 112c have been described as being configured in three stages of 0 dB, 10 dB, and 20 dB. However, the present invention can also be implemented by dividing the structure into more stages.
[0040]
In the above description, the example has been described in which the two responders, ie, the first responder 103a and the second responder 103b are used. However, the present invention can be similarly implemented even when there are three or more responders. is there.
[0041]
Further, the responders 103a and 103b that have been able to read data by the interrogator 102 by communication may receive the transmission stop signal transmitted from the interrogator 102 and stop the transmission of data. .
[0042]
(Embodiment 2)
FIG. 2 shows a block diagram of a mobile object identification system according to Embodiment 2 of the present invention. 2 is different from the first embodiment in FIG. 1 in that ASK modulation with a different modulation degree is performed according to the number of communications. In FIG. 2, an interrogator-side antenna 201 and a responder-side antenna 204 function as an antenna for microwave communication between the interrogator 202 and the responders 203a and 203b, and are composed of, for example, a single or a plurality of patch antennas. Has been.
[0043]
The microwave signal generated by the signal source 205 of the interrogator 202 is modulated by the modulator 215 and then distributed to the transmission side and the reception side by the distribution circuit. The signal on the transmission side passes through the demultiplexer 207 and is transmitted to the interrogator side. It is transmitted from the antenna 201. The transmitted microwave signals are received by the responder side antennas 204 of the responders 203a and 203b, and are ASK modulated by changing the reflectance by the ASK modulation unit 209 according to the control signal emitted from the control unit 208. It is transmitted from the side antenna 204 to the interrogator 202.
[0044]
The ASK modulation unit 209 includes a reflection condition switching unit 213, a 0 dB absorber 212a, a 10 dB absorber 212b, and a 20 dB absorber 212c, and is turned on by switching between the 0 dB absorber 212a and the 10 dB absorber 212B in the first communication. -ASK modulation with an OFF ratio of 10 dB.
[0045]
The ASK-modulated microwaves transmitted from the responders 203a and 203b are received by the interrogator antenna 201, distributed to the receiver by the duplexer 207, demodulated by the reception demodulator 210, and processed by the data processor 211. Data from the responders 203a and 203b is read.
[0046]
When the data can be read by the first communication, the transmission signal is modulated by the control signal issued from the control unit 214 of the interrogator 202, and a data transmission stop request is transmitted to the responders 203a and 203b. . The responders 203a and 203b that have not received the cancellation request perform ASK modulation with an ON-OFF ratio of 20 dB by switching between the 0 dB absorber 212a and the 20 dB absorber 212c, and retransmit the signal.
[0047]
As described above, each of the responders 203a and 203b decreases the ON-OFF ratio during the first communication and increases the ON-OFF ratio during the second and subsequent communication, whereby the interrogator 202 performs the first communication. By separating and demodulating the response signals of the responders 203a and 203b that have failed to read data at the difference in modulation degree, even if a plurality of responders 203a and 203b in the communication area simultaneously transmit response signals, A moving body identification system in which the interrogator 202 can read the data of the plurality of responders 203a and 203b in a short time can be realized.
[0048]
In the above description, the example in which the absorber 212 is configured in three stages of 0 dB, 10 dB, and 20 dB has been described.
[0049]
Further, in the above description, an example in which two responders, the first responder 203a and the second responder 203b, are described. However, the present invention can be similarly implemented even when there are three or more responders. is there.
[0050]
In the above description, the example of the configuration in which all the responders 203a and 203b switch the modulation degree in the second and subsequent communications has been described. However, the modulation degree is switched by the responders 203a and 203b at different communication times. The configuration can be similarly implemented.
[0051]
(Embodiment 3)
FIG. 3 shows a block diagram of a mobile object identification system according to Embodiment 3 of the present invention. 3 differs from the first embodiment of FIG. 1 in that PSK modulation is performed using phase shifters having different phase amounts. In FIG. 3, the microwave signal generated by the signal source 305 of the interrogator 302 is distributed to the transmission side and the reception side by the distribution circuit 306, and the signal on the transmission side is transmitted from the interrogator side antenna 301 through the demultiplexer 307. The
[0052]
The transmitted microwave signal is received by the responder side antenna 304 of the responder 303, and is PSK modulated by changing the phase by the PSK modulation unit 309 according to the control signal emitted from the control unit 308. To the interrogator 302.
[0053]
The PSK modulation unit 309 includes a reflection condition switching unit 313, a 0-degree phase shifter 312a, a 170-degree phase shifter 312b, and a 180-degree phase shifter 312c, and the 0-degree phase shifters 312a and 170 at the first communication. PSK modulation is performed by switching the phase shifter 312b.
[0054]
The PSK modulated microwaves transmitted from the responders 303 a and 303 b are received by the interrogator antenna 301, distributed to the receiving side by the demultiplexer 307, demodulated by the reception demodulator 310, and processed by the data processor 311. Data from the responders 303a and 303b is read.
[0055]
When the data can be read by the first communication, the transmission signal is modulated by the control signal issued from the control unit 314 of the interrogator 302, and the data transmission stop request is transmitted to the responders 303a and 303b. . The responders 303a and 303b that have not received the cancellation request perform PSK modulation by switching between the 0-degree phase shifter 312a and the 180-degree phase shifter 312c, and retransmit the signal.
[0056]
As described above, the responders 303a and 303b 1 By changing the modulation degree of the response signal of the first communication and the communication after the second communication, the response signal of the responders 303a and 303b in which the interrogator 302 failed to read the data in the first communication is different in the modulation degree. Thus, even if a plurality of responders 303a and 303b in the communication area simultaneously transmit response signals, the interrogator 302 can read the data of the plurality of responders 303a and 303b in a short time. A body identification system can be realized.
[0057]
In the above description, the example in which the phase shifter 312 is configured in three stages of 0 degrees, 170 degrees, and 180 degrees has been described.
[0058]
In the above description, the example has been described in which the two responders, the first responder 303a and the second responder 303b, are used, but the present invention can be similarly implemented even if there are three or more responders. is there.
[0059]
In the above description, the example in which the PSK modulation is performed by combining the 0 degree phase shifter 312a and the 170 degree phase shifter 312b or the 0 degree phase shifter 312a and the 180 degree phase shifter 312c has been described. A configuration in which the 0-degree phase shifter 312a is combined as a 10-degree phase shifter and a 20-degree phase shifter can be similarly implemented.
[0060]
In the above description, an example using PSK modulation has been described. However, a 0-degree phase shifter, an 80-degree phase shifter, a 90-degree phase shifter, a 170-degree phase shifter, a 180-degree phase shifter, and a 260-degree phase shifter. The same can be implemented using QPSK modulation using a phase shifter and a 270 degree phase shifter.
[0061]
In the above description, the example in which the modulation degree of the response signal is changed between the first communication and the second and subsequent communication has been described. However, several times, for example, the third and fourth communication are performed. Alternatively, the modulation degree of the answer signal may be changed.
[0062]
In the above description, the example in which the modulation degree of the response signal is changed during the first communication and the second and subsequent communication has been described. However, the modulation degree may be appropriately changed during communication. Good.
[0063]
(Embodiment 4)
FIG. 4 shows a block diagram of a mobile object identification system according to Embodiment 4 of the present invention. 4 differs from the first embodiment of FIG. 1 in that PSK modulation is performed by combining a phase shifter and an attenuator having different phase amounts. In FIG. 4, the microwave signal generated by the signal source 405 of the interrogator 402 is distributed to the transmission side and the reception side by the distribution circuit 406, and the signal on the transmission side is transmitted from the interrogator side antenna 401 through the demultiplexer 407. The
[0064]
The transmitted microwave signal is received by the responder side antenna 404 of the responder 403, is PSK modulated by changing the phase by the PSK modulation unit 409 according to the control signal emitted from the control unit 408, and the responder side antenna 404 Is transmitted to the interrogator 402.
[0065]
The PSK modulation unit 409 includes a reflection condition switching unit 413, an attenuator 417, a 0 degree phase shifter 412a, and a 180 degree phase shifter 412b, and the signal attenuated by the attenuator 417 is 0 degree during the first communication. PSK modulation is performed by switching between the phase shifter 412a and the 180 degree phase shifter 412b.
[0066]
The attenuator 417 has an attenuation amount of 10 dB, for example. The PSK modulated microwaves transmitted from the responders 403a and 403b are received by the interrogator antenna 401, distributed to the receiving side by the duplexer 407, demodulated by the reception demodulator 410, and processed by the data processor 411. Data from the responders 403a and 403b is read.
[0067]
When the data can be read by the first communication, the transmission signal is modulated by the control signal issued from the control unit 414 of the interrogator 402, and a data transmission stop request is transmitted to the responders 403a and 403b. . The responders 403a and 403b that have not received the cancellation request perform PSK modulation on the signal that is not attenuated by the attenuator 417 by switching between the 0-degree phase shifter 412a and the 180-degree phase shifter 412b, and retransmit the signal.
[0068]
As described above, each of the responders 403a and 403b changes the modulation degree and the reflection amount of the response signal of the first communication and the second and subsequent communication, so that the interrogator 402 transmits the data in the first communication. Even if a plurality of responders 403a and 403b in the communication area simultaneously transmit response signals by separating and demodulating the response signals of the responders 403a and 403b that have failed to be read depending on the difference in modulation degree and reflection amount, It is possible to realize a moving body identification system in which the device 402 can read the data of the plurality of responders 403a and 403b in a short time.
[0069]
In the above description, the example in which the attenuation amount of the attenuator 417 is configured with 10 dB has been described. However, the present invention can be similarly implemented even with an attenuation device having other attenuation amounts such as 5 dB and 15 dB.
[0070]
Further, in the above description, an example in which two responders, the first responder 403a and the second responder 403b, are described, but the present invention can be similarly implemented even when three or more responders exist. is there.
[0071]
In the above description, an example in which one attenuator 417 is configured has been described. However, a configuration in which a plurality of attenuators, for example, 5 dB, 10 dB, and 15 dB are configured and switched can be similarly implemented.
[0072]
In the above description, an example using PSK modulation has been described. However, QPSK modulation using a 0 degree phase shifter, a 90 degree phase shifter, a 180 degree phase shifter, and a 270 degree phase shifter may be used. It can be implemented similarly.
[0073]
In the above description, the example using the 0-degree phase shifter 412a and the 180-degree phase shifter 412b has been described. However, other phase shifters, for example, the 170-degree phase shifter, are used to shift the phase together with the attenuation. It can be similarly implemented as a configuration for switching the amount of change.
[0074]
(Embodiment 5)
FIG. 5 shows a communication method of the mobile object identification system according to the fifth embodiment of the present invention. The data string is composed of a solid recognition data string and an information data string. The difference from the first embodiment is that ASK modulation with a different modulation degree is performed according to communication data.
[0075]
The responders 501a, 501b, 501c, and 501d that have sequentially entered the communication area receive the microwave signal transmitted from the interrogator 510, the modulation degree of the ON-OFF ratio 20 dB, and the information data string 503 when transmitting the solid recognition data string 502. At the time of transmission, a response signal is returned by reflecting with a modulation degree of 10 dB. The solid recognition data string 502 is smaller than the information data string 503. For example, the solid recognition data string 502 is 4 bytes and the information data string 503 is 128 bytes. The information data string 503a and the solid recognition data string 502b are simultaneously transmitted to the interrogator 510. The interrogator 510 separates and demodulates only the solid recognition data string 502b having a large modulation degree, and reads the data of the responder 501b.
[0076]
Thereafter, a transmission stop command 504 is transmitted to the responder 501b to stop sending the response signal. Similarly, the information data string 503c and the solid recognition data string 505a, and the information data string 506c and the solid recognition data string 502d are transmitted at the same time. However, the interrogator 510 transmits only the solid recognition data strings 505a and 502d having a large modulation degree. Separation and demodulation are performed, and data of the responders 501a and 501d are read. The interrogator 510 manages the received solid recognition data strings 502 and 505, and continues reading as long as there is a responder 501 that has not read the information data strings 503 and 506 (the responder 501c in FIG. 5).
[0077]
As described above, each of the responders 501a, 501b, 501c, and 501d has a response signal at the time of solid recognition data string communication with a small data amount and a short communication time, and an information data string communication with a large data amount and a long communication time. By changing the modulation degree of the interrogator 510, the interrogator 510 can separate and recognize the solid recognition data strings of the plurality of responders 501a, 501b, 501c, and 501d by the difference in the modulation degree, and can manage the responders in the area. Therefore, even if a plurality of responders 501a, 501b, 501c, and 501d in the communication area transmit a response signal at the same time, the interrogator 510 does not read the data of the plurality of responders 501a, 501b, 501c, and 501d in a short time. A mobile object identification system that can be read without any problem can be realized.
[0078]
In the above description, an example in which the four responders 501a to 501d are used has been described. However, the present invention can be similarly implemented even when five or more responders exist.
[0079]
In the above description, the responders 501a, 501b, 501c, and 501d have been described as examples of configurations in which ASK modulation is performed. However, the present invention can be similarly applied even when the PSK modulation is performed using phase shifters having different modulation degrees. Is possible.
[0080]
In the above description, the example of the configuration in which only the response signal having a large modulation degree is demodulated has been described. However, the present invention can be similarly implemented even if the response signal having a small modulation degree is separated and demodulated.
[0081]
In the above description, the example of the configuration in which the transmission stop command is transmitted to the responders 501a, 501b, 501c, and 501d whose data has been read has been described. The present invention can also be implemented in the same manner by configuring the units 501a, 501b, 501c, and 501d to transmit a retransmission instruction for causing data to be retransmitted at a specific timing.
[0082]
【The invention's effect】
As described above, according to the present invention, it is possible to obtain an advantageous effect that a small and inexpensive mobile object identification system capable of reading a plurality of responders in the same area can be realized.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a moving object identification system according to a first embodiment of the present invention.
FIG. 2 is a block diagram showing a moving object identification system according to a second embodiment of the present invention.
FIG. 3 is a block diagram showing a moving object identification system according to a third embodiment of the present invention.
FIG. 4 is a block diagram showing a moving object identification system according to a fourth embodiment of the present invention.
FIG. 5 is a diagram showing a communication method of a mobile object identification system according to a fifth embodiment of the present invention.
FIG. 6 is a diagram for explaining a communication method of a conventional non-contact IC card system.
[Explanation of symbols]
101, 201, 301, 401, 501 Interrogator side antenna
102, 202, 302, 402, 510 Interrogator
103, 203, 303, 403 Responder
104, 204, 304, 404 Responder side antenna
105, 205, 305, 405 Signal source
106, 206, 306, 406 Distribution circuit
107, 207, 307, 407 duplexer
108, 208, 308, 408 control unit
109, 209 ASK modulator
110, 210, 310, 410 Reception demodulation unit
111, 211, 311, 411 Data processing unit
112, 212 Absorber
113, 213, 313, 413 switcher
114, 214, 314, 414 control unit
115, 215, 315, 415 modulator
116, 416 Demodulator
117 random number generator
309, 409 PSK modulator
312 and 412 phase shifters
417 Attenuator
502 Solid recognition data string
503 Information data string
504 Transmission stop command
505 Solid recognition data string
506 Information data string
507 Transmission stop command
508 Transmission stop command

Claims (16)

A signal source that generates an output signal, a modulation unit that modulates the output signal from the signal source, an antenna that transmits the output signal modulated by the modulation unit, and a reflected wave as a response signal received by the antenna is output A demultiplexer that demultiplexes the signal, a demodulator that demodulates the response signal, a data processor that processes a signal from the demodulator, and a controller that controls the interrogator based on the data of the processor Interrogator,
A signal sent from the interrogator is input, and a responder antenna that sends a reflected wave as the response signal to the antenna of the interrogator, a demodulator that demodulates the received input signal, a demodulator each demodulation controller for outputting a control signal for controlling the modulation of the input signal used for the response signal, using the control signals for each demodulation of the demodulator, the first amplitude modulating the different absorption, A modulator that controls a switch that switches between two absorbers having different combinations from the second and third absorbers, amplitude-modulates an input signal used for the response signal, and outputs the response signal as the response signal; The responder
A mobile object identification system.   The first demodulated signal amplitude-modulates the input signal from the interrogator into a reflected wave as a response signal by switching the first and second absorbers, and the second and subsequent demodulated signals are The moving body identification system according to claim 1, wherein amplitude modulation is performed by switching the first and third absorbers.   The mobile object identification system according to claim 1, wherein the absorption amount of the first absorber is 0 dB, the absorption amount of the second absorber is 10 dB, and the absorption amount of the third absorber is 20 dB.   The response signal of the responder is composed of a data string including a solid recognition data string and an information data string, and when the solid recognition data string is transmitted, by switching the first and third absorbers, 2. The moving body identification system according to claim 1, wherein the input signal is amplitude-modulated to a reflected wave as a response signal, and amplitude modulation is performed by switching the first and second absorbers when transmitting the information data string. A signal source that generates an output signal, a modulation unit that modulates the output signal from the signal source, an antenna that transmits the output signal modulated by the modulation unit, and a reflected wave as a response signal received by the antenna is output A demultiplexer that demultiplexes the signal, a demodulator that demodulates the response signal, a data processor that processes a signal from the demodulator, and a controller that controls the interrogator based on the data of the processor Interrogator,
A signal sent from the interrogator is input, and a responder antenna that sends a response signal to the antenna of the interrogator, a demodulator that demodulates the received input signal, and the number of communications with the interrogator A control unit that outputs a control signal for controlling a modulation degree of an input signal used for the response signal for each demodulation of the demodulating unit, and a first and a second that perform phase modulation with different phase amounts using the control signal. A switch that switches between the two phase shifters of different combinations for each demodulation of the demodulator according to the number of times of communication with the interrogator from the third phase shifter, and the response A transponder having a modulation unit that phase-modulates an input signal used as a signal and outputs the signal as the response signal;
A mobile object identification system.   The first demodulated signal is obtained by phase-modulating the input signal from the interrogator into a reflected wave as a response signal by switching the first and second phase shifters. 6. The moving body identification system according to claim 5, wherein phase modulation is performed by switching the first and third phase shifters.   6. The moving body according to claim 5, wherein the phase amount of the first phase shifter is 0 degrees, the phase amount of the second phase shifter is 170 degrees, and the phase amount of the third phase shifter is 180 degrees. Identification system.   The response signal of the responder is composed of a data string including a solid recognition data string and an information data string, and when the solid recognition data string is transmitted, by switching the first and third phase shifters, 6. The mobile object identification system according to claim 5, wherein the input signal is phase-modulated to a reflected wave as a response signal, and phase modulation is performed by switching the first and second phase shifters when transmitting the information data string. A signal source that generates an output signal, a modulation unit that modulates the output signal from the signal source, an antenna that transmits the output signal modulated by the modulation unit, and a reflected wave as a response signal received by the antenna is output A demultiplexer that demultiplexes the signal, a demodulator that demodulates the response signal, a data processor that processes a signal from the demodulator, and a controller that controls the interrogator based on the data of the processor Interrogator,
A signal sent from the interrogator is input, and a responder antenna that sends a response signal to the antenna of the interrogator, a demodulator that demodulates the received input signal, and the number of communications with the interrogator A control unit that outputs a control signal for controlling a modulation degree and a reflection amount of an input signal used for the response signal for each demodulation of the demodulation unit, an attenuator that outputs an attenuation signal with a different attenuation amount, and the attenuation signal The first, second, and third phase shifters that perform phase modulation with different phase amounts, and different combinations of the attenuation signal and the phase shifter, depending on the number of times of communication with the interrogator, A switching unit that switches for each demodulation of the demodulating unit, a control unit that controls the phase using the control signal, performs phase modulation, and outputs the response signal as a response unit;
A mobile object identification system.   The first demodulated signal is phase-modulated to a reflected wave as a response signal by attenuating the input signal from the interrogator with the attenuator and switching between the first and second phase shifters. The second demodulated signal is phase-modulated by switching the first and second phase shifters without using the attenuator, and the third demodulated signal is not used with the attenuator. The moving body identification system according to claim 9, wherein phase modulation is performed by switching between the first and third phase shifters.   The moving body according to claim 9, wherein the phase amount of the first phase shifter is 0 degree, the phase amount of the second phase shifter is 170 degrees, and the phase amount of the third phase shifter is 180 degrees. Identification system.   The moving body identification system according to claim 9, wherein the attenuation amount of the attenuator is 10 dB.   The response signal of the responder is composed of a data string including a solid recognition data string and an information data string, and the first and third phase shifters are switched without using the attenuator when transmitting the solid recognition data string. 10. The moving body according to claim 9, wherein phase modulation is performed on a reflected wave as a response signal, attenuation is performed by the attenuator during transmission of an information data string, and phase modulation is performed by switching the first and third phase shifters. Identification system.   The response signal of the responder is composed of a data string including a solid recognition data string and an information data string, and when the first solid recognition data string is transmitted, the input signal from the interrogator is attenuated by the attenuator. By switching the first and third phase shifters, phase modulation is performed on the reflected wave as a response signal, and the signal from the interrogator is attenuated by the attenuator at the time of transmission of the first information data string, Phase modulation is performed by switching the first and second phase shifters, and the first and third phase shifters are switched without using the attenuator during the second and subsequent solid recognition data string transmission. The phase modulation is performed by switching the first and second phase shifters without using the attenuator during the second and subsequent transmission of the information data string, wherein the phase modulation is performed on the reflected wave as the response signal. Mobile object identification Stem.   The mobile body identification system according to any one of claims 1, 5, and 9, wherein a transmission stop command from the interrogator is recognized and response signal transmission from the responder is stopped.   The mobile object identification system according to claim 1, comprising an interrogator having an antenna that transmits an output signal and a reception antenna that receives a response signal, and a responder that communicates with the interrogator. .

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