JP2006121156A - Radio communications system - Google Patents

Radio communications system Download PDF

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Publication number
JP2006121156A
JP2006121156A JP2004303997A JP2004303997A JP2006121156A JP 2006121156 A JP2006121156 A JP 2006121156A JP 2004303997 A JP2004303997 A JP 2004303997A JP 2004303997 A JP2004303997 A JP 2004303997A JP 2006121156 A JP2006121156 A JP 2006121156A
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Prior art keywords
responder
wave
interrogation
interrogator
directivity
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JP2004303997A
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Japanese (ja)
Inventor
Atsuo Chiga
Takashi Matsuyama
Shigeru Yamazaki
敦夫 千賀
茂 山▲崎▼
崇 松山
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Nippon Signal Co Ltd:The
日本信号株式会社
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Abstract

PROBLEM TO BE SOLVED: To provide a radio communication system capable of starting communication with a responder existing in a communication area of an interrogator reliably and in a short time.
An interrogator 1 includes two transmission antennas 11 and 12 whose directivities can be variably controlled, and directs first and second interrogation waves having different frequencies from the two transmission antennas 11 and 12 of the interrogator 1. Only the responder 2 existing at the point where the first interrogation wave and the second interrogation wave overlap each other receives the first and second interrogation waves and sends back the response wave.
[Selection] Figure 1

Description

  The present invention relates to a wireless communication system that performs wireless communication between an interrogator and a responder, and more particularly, to a wireless communication system that enables an interrogator to reliably communicate with a desired responder.

Conventionally, a question wave is radiated from an interrogator, and a responder that exists in the communication area of this interrogation wave receives the interrogation wave and returns a response wave to the interrogator. For example, it is represented by an RFID (Radio Frequency Identification) system. There is known a wireless communication system using an interrogator-responder (see, for example, Patent Documents 1 to 3).
JP-A-8-248127 JP-A-10-224259 JP 2004-88755 A

  By the way, in this type of conventional wireless communication system, when an interrogator emits an interrogation wave to a predetermined communication area and a responder exists in the communication area, the responder receives the interrogation wave and receives power supply. When sufficient power is obtained, the operation is started and a response wave is returned. For this reason, for example, in the case of a system in which the responder passes through the communication area of the interrogator at high speed, the stay time in the communicable area where sufficient power can be obtained is limited, so as a measure to ensure communication time, It is conceivable to increase the radio output to widen the transmission area of the interrogation wave. However, wireless output is restricted by the Radio Law. Further, if the transmission area of the interrogation wave is expanded, there is a possibility that a response device other than the desired response device may react, and it is not preferable to simply expand the transmission area.

  In addition, if there are multiple responders in the interrogation wave communication area, the multiple responders in the communication area receive the interrogation wave and send back the response wave. If the response wave is masked and there is a responder that cannot be recognized by the interrogator, the responder determines that the communication has been completed even though it is not recognized by the interrogator, causing a problem on the system. .

  Furthermore, when there is a need to communicate with a plurality of responders within a certain time, for example, in an RFID system, for example, when communicating with each responder conventionally, the upper bits of the ID number attached to the responder The communication protocol is such that the ID number is narrowed down until only the response wave of each responder is received bit by bit. For example, as shown in FIG. 11, four responders 101 with ID numbers “0011”, “0010”, “1100”, and “1111”, for example, are included in the communication area of the interrogator 100 (the hatched portion in the figure). In the case where it exists, when the responder with the ID number “0010” is read, the flowchart of FIG. 12 is read, and when the responder with the ID number “1111” is read, the flowchart of FIG. In the figure, the path to start communication with each responder is indicated by a solid line. As can be seen from FIGS. 12 and 13, the response times of the responders with ID numbers “0010” and “1111” are different. Thus, in a conventional wireless communication system, in the case of a system that needs to communicate with a plurality of responders in a communication area within a certain time, it takes time to communicate with each responder, and the responder Due to this, the time until the start of communication was irregular.

  The present invention has been made paying attention to the above problems, and an object thereof is to provide a wireless communication system in which an interrogator can start communication with a desired responder reliably and in a short time.

  Therefore, according to the first aspect of the present invention, a radio communication system in which an interrogator and a responder communicate information by transmitting an interrogation wave from the interrogator and the responder receiving the interrogation wave returns a response wave. The interrogator includes two transmission antennas that transmit first and second interrogation waves having different frequencies, and a directivity control unit that variably controls the directivity of at least one of the two transmission antennas. Provided, and the first and second interrogation waves are configured to communicate only with a responder existing at a position where they overlap.

  In such a configuration, the interrogator transmits the first interrogation wave and the second interrogation wave having different frequencies from the two transmission antennas by variably controlling the directivity of at least one of the transmission antennas by the directivity control unit. A response wave is received only from the responder that exists at the position where the first and second interrogation waves overlap, and communication is made with the responder.

According to a second aspect of the present invention, the responder is configured to be in the response wave return mode when both the first and second interrogation waves transmitted by the interrogator are received.
In such a configuration, the responder responds when both the first and second interrogation waves transmitted by the interrogator are received.

According to a third aspect of the present invention, it is preferable that the two transmission antennas have a configuration in which directivity can be varied by the directivity control unit.
As in claim 4, the directivity of the transmitting antenna that transmits the first interrogating wave is fixed and transmitted, while the second interrogating wave that has a smaller transmission area than the first interrogating wave is transmitted with the directivity of the transmitting antenna. It may be configured to be variably controlled so that scanning is possible including the transmission area of the first interrogation wave.

According to a fifth aspect of the present invention, the interrogator includes a radio wave intensity measuring unit that measures the intensity of the received radio wave, and the radio wave received from the responder when the measured value of the radio wave intensity measuring unit is equal to or greater than a predetermined value. It is preferable to include a position estimation unit that determines and estimates the position of the responder based on the directivity information of each transmission antenna.
In such a configuration, the interrogator measures the intensity of the received radio wave by the radio field intensity measuring means, and if the measured value is equal to or greater than a predetermined value, the interrogator determines that the radio wave is from the responder and estimates the position of the responder by the position estimating means .

As in claim 6, the directivity of each of the transmission antennas whose directivity can be varied is sequentially variably set, the interrogation wave from the transmission antenna is scanned, and the measurement value of the radio wave intensity measuring means is equal to or greater than a predetermined value. It may be configured to determine that there is a responder when it becomes.
The directivity of each transmitting antenna may be controlled by the directivity control unit based on position information of a specific responder given from a management device connected to the interrogator.
According to another aspect of the present invention, the responder may be configured to generate an operation clock of a built-in CPU using the first and second interrogation waves.

As in claim 9, when the transponder enters the standby mode from the stop mode when entering the fixed transmission area of the first interrogation wave, the transponder receives the interrogation wave in the standby mode. The transponder may be configured to enter a communication mode.
In such a configuration, when the responder enters the transmission area of the first interrogation wave, the transponder shifts from the stop mode to the standby mode, and when the second interrogation wave is received in the standby mode, the transponder shifts to the communication mode. As a result, the transmission area of the first interrogation wave is set wide to secure the communication time, and interference with other responders can be prevented.

  As described above, according to the wireless communication system of the present invention, the directivity of at least one interrogation wave of two interrogation waves is variably controlled, and communication is performed only with a responder that exists at a position where the two interrogation waves overlap. Therefore, even if there are many responders in the communication area of the interrogator, it is possible to communicate with each responder reliably, and the interrogator recognizes it even though the conventional responder responds. The problem of not doing can be solved. In addition, by increasing the scanning speed of the interrogation wave, it is possible to communicate with a large number of responders in a short time, and communication between the interrogator and the responder can be speeded up. Furthermore, since the transmission direction of the interrogation wave can be changed to an arbitrary direction, the problem of inability to communicate due to multipath fading can be solved, and communication with the responder can be reliably performed regardless of the location of the responder.

  Further, the directivity of the first interrogation wave is transmitted while the directivity of the first interrogation wave is fixed, the directivity of the second interrogation wave having a narrower transmission area than the first interrogation wave is varied, and the transmission area of the first interrogation wave is scanned. However, when entering the transmission area of the first interrogation wave, the mode is changed from the stop mode to the standby mode, and when the second interrogation wave is received, the communication mode is set. In such a system, by setting a wide transmission area for the first interrogation wave, it is possible to ensure a sufficient communication time without using an expensive CPU or the like with a fast rise speed as a responder.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a system schematic diagram showing a first embodiment of a wireless communication system according to the present invention.
In FIG. 1, the wireless communication system of the present embodiment includes an interrogator 1, a responder 2 such as a tag, and a management device 3 that is connected to the interrogator 1 and communicates information.

The interrogator 1 transmits two interrogation waves having different frequencies by variably controlling the directivity of the transmission antennas 11 and 12, and receives a response wave from the responder 2 to communicate data with the responder 2. FIG. 2 shows the configuration.
In FIG. 2, the interrogator 1 includes two transmission antennas 11 and 12 for transmitting interrogation waves, a reception antenna 13 for receiving response waves, and interrogation waves having different frequencies from each other. When each of the transmission units 14 and 15 to output, the reception unit 16 that receives the response wave from the reception antenna 13, the directivity control unit 17 that controls the directivity of the transmission antennas 11 and 12, and when the response wave is received The position information detection unit 18 that estimates the position of the responder 2 and the control unit 19 that controls the operation of each unit of the interrogator 1 and communicates information with the management device 3.

  The transmission antennas 11 and 12 are configured by a conventionally known adaptive array antenna in which a plurality of antenna elements are arranged in an array so that the directivity can be changed and the transmission direction of the interrogation wave can be changed. The transmission unit 14 outputs, for example, an interrogation wave obtained by modulating a carrier wave having a frequency f1 with transmission data to the transmission antenna 11 as a first interrogation wave. The transmission unit 15 outputs an unmodulated carrier wave having a frequency f2 to the transmission antenna 12 as a second interrogation wave. In this embodiment, it is assumed that the transmission radio waves transmitted from the transmission antennas 11 and 12 have a narrow transmission area with high directivity compared to conventional transmission antennas.

  The directivity control unit 17 controls the transmission units 14 and 15 based on the directivity control command of the control unit 19 to variably control the directivity of the transmission antennas 11 and 12, in other words, the radiation direction of the interrogation wave. . The position information detection unit 18 transmits a reception intensity measurement function for measuring the intensity of the radio wave received via the reception antenna 13 based on the reception state of the reception unit 16 and when the measurement value of the reception intensity is a predetermined value or more. Distance measurement function and position estimation for estimating the distance to the responder 2 and the position of the responder 2 (for example, latitude and longitude) using the interrogation wave radiation direction information of the antennas 11 and 12 and the distance information between the transmitting antennas 11 and 12 And the estimated responder position information is sent to the control unit 19. Therefore, the position information detection unit 18 has functions of reception intensity measurement means and position estimation means.

The responder 2 becomes a response wave return mode when both the first and second interrogation waves having different frequencies f1 and f2 transmitted from the interrogator 1 are received, and the configuration is shown in FIG.
In FIG. 3, the responder 2 includes a reception antenna 21 that receives the interrogation wave, a transmission / reception antenna 22 that receives the interrogation wave and returns a response wave obtained by modulating the received interrogation wave with response data, and reception of the reception antenna 21. A data extraction unit 23 that extracts data from the first interrogation wave and the second interrogation wave by, for example, mixing processing using a mixer, a power supply unit 24 that extracts and supplies power from the interrogation wave received by the receiving antenna 21, and a power supply The CPU 25 operates by supplying power from the unit 24 and outputs response data corresponding to the data extracted by the data extraction unit 23, and the second interrogation wave received by the transmission / reception antenna 22 is modulated by the response data output by the CPU 25. And a modulation unit 26 that outputs a response wave to the transmission / reception antenna 22. Note that the clock for operating the CPU 25 of the responder 2 may be generated using the carrier wave component and the modulated wave component of the interrogation wave as in the conventional case.

Next, the operation of the wireless communication system of this embodiment will be described with reference to the flowcharts shown in FIGS.
FIG. 4 shows an example in which communication is performed by designating a desired responder identified by the management apparatus 3.
In step 1 (indicated by S1 in the figure, the same shall apply hereinafter), the management device 3 designates the ID of the desired responder 2 and transmits it to the controller 19 of the interrogator 1.
In step 2, the control unit 19 instructs the directivity control unit 17 to set the directivity of the transmission antenna 12, that is, the transmission direction θ2 of the second interrogation wave to an initial value. Thereby, the directivity control unit 17 controls the transmission unit 15 so that the interrogation wave transmission direction of the transmission antenna 12 becomes the initial value θ2 (0).

In step 3, as in step 2, the directivity control unit 17 controls the transmission unit 14 so that the interrogation wave transmission direction of the transmission antenna 11 becomes the initial value θ1 (0).
In step 4, the position information detection unit 18 measures the intensity of the received radio wave based on the output state of the reception unit 16 to determine whether or not the value is equal to or greater than a predetermined value. If it is determined that the response wave from the device 2 is a response wave, the process proceeds to step 5. If the determination is NO and the determination is NO, step 5 is skipped and the process proceeds to step 8 described later.

In step 5, it is determined whether or not the ID information obtained from the received response wave matches the ID specified by the management apparatus 3. If not, go to step 8.
In step 6, the position information detection unit 18 transmits information from the interrogator 1 to the responder 2 based on the transmission direction information of the first and second interrogation waves at that time and the distance data between the transmission antennas 11 and 12 stored in advance. The distance measurement and the position of the responder are estimated, and the desired position detection operation of the responder 2 is executed.
In step 7, communication with the responder 2 is started.

  On the other hand, if each determination in steps 4 and 5 is NO and the process proceeds to step 8, it is determined in step 8 whether or not the transmission direction θ1 of the transmission antenna 11 is a predetermined maximum value MAX. Then, the transmission direction θ1 of the transmission antenna 11 is increased by Δθ1, and the process returns to step 4 to measure the reception intensity. If the determination in step 8 is YES, the process proceeds to step 10, where it is determined whether or not the transmission direction θ2 of the transmission antenna 12 is a predetermined maximum value MAX. The transmission direction θ2 of the antenna 12 is increased by Δθ2, and the process returns to step 3 to return the transmission direction θ1 of the transmission antenna 11 to the initial value θ1 (0), and then the transmission direction θ1 of the transmission antenna 11 is changed from the initial value θ1 (0) to Variable again to MAX. When the determination in step 10 is YES, it is determined in step 12 that there is no desired responder.

  In this way, the transmission direction θ1 of the transmission antenna 11 is sequentially varied for each of the transmission directions θ2 (0) to MAX of the transmission antenna 12, the two interrogation waves are scanned, and the responder 2 is positioned at the position where the two interrogation waves overlap. Is present, the responder 2 receives both of the two interrogation waves with the receiving antenna 21, and is supplied with power from the power supply unit 24 to the CPU 25 to operate the CPU 25, and the data extraction unit 23 extracts data and the CPU 25 Is transmitted. The CPU 25 transmits response data corresponding to the received data to the modulation unit 26, modulates the unmodulated second interrogation wave received by the transmission / reception antenna 22 by the modulation unit 26 with the response data, and transmits the response wave via the transmission / reception antenna 22. Send back. The interrogator 1 starts communication if the ID information of the received response wave matches the ID of the desired responder 2 specified by the management device 3.

FIG. 5 shows an example in which the management apparatus 3 communicates by designating a desired responder position.
In step 21, the management device 3 designates a desired position of the responder 2 and transmits it to the control unit 19 of the interrogator 1.
In step 22, the control unit 19 calculates the transmission direction of each of the transmission antennas 11 and 12 based on the input position information so that the two interrogation waves overlap at the designated point, and the transmission direction of the obtained transmission antenna 11 is obtained. A set value θ1 (m) of θ1 is commanded to the directivity control unit 17, and the directivity control unit 17 controls the transmission unit 14 so that the directivity of the transmission antenna 11 becomes the set value θ1 (m).
In step 23, as in step 22, the directivity control unit 17 controls the transmission unit 15 so that the transmission direction θ2 of the transmission antenna 12 becomes the set value θ2 (n).

  In step 24, the position information detection unit 18 measures the intensity of the received radio wave based on the reception state of the reception unit 16, and determines whether or not the measurement value is equal to or greater than a predetermined value. If the determination is YES at a predetermined value or more, it is determined that a responder exists at the designated position, and the process proceeds to step 25 to start communication with the responder 2. On the other hand, if the reception intensity is less than the predetermined value and the determination is NO, it is determined that there is no responder at the designated position. When there is no responder, another position information is designated from the management apparatus 3, or the operation is terminated without designating another position information.

  As described above, since the wireless communication system of the present embodiment communicates only with the responder 2 that exists at the position where the two interrogation waves overlap, even when there are a large number of responders in the communication area of the interrogator 1, Communication with each responder 2 can be ensured. Therefore, the problem that the interrogator 1 does not recognize despite the response of the responder 2 as in the prior art can be solved. In addition, since the scanning speed of the interrogation wave can be made extremely high by the adaptive array antenna, it is possible to communicate with a large number of responders existing in the communication area in a short time, and the communication between the interrogator and the responder is fast. Is possible.

  Further, in the conventional wireless communication system, depending on the location of the responder 2, communication with the responder 2 may be disabled due to multipath fading or the like. Since the transmission direction of the interrogation wave can be varied in any direction, the problem of inability to communicate due to multipath fading can be solved, and the place (null point) where the interrogation wave cannot be received can be eliminated. It becomes possible to reliably communicate with the responder 2 regardless of the location of the.

Here, the responder position estimation operation of the wireless communication system of the present embodiment will be described with reference to FIGS.
FIG. 6 is an explanatory diagram of a two-dimensional case in which the responder 2 is on the same plane as the interrogator 1.

In FIG. 6, as known information, the distance between the transmission antennas 11 and 12 is D, the transmission direction of the interrogation wave of the transmission antenna 11 is θ1, and the transmission direction of the interrogation wave of the transmission antenna 12 is θ2.
When the distance from the interrogator 1 to the responder 2 is L, and the offset amount of the responder 2 viewed from the transmitting antennas 11 and 12 is Y1 and Y2,
Y1 = Ltanθ1
Y2 = Ltanθ2
D = Y1 + Y2
It becomes.
From the above three equations, Y1, Y2, and L can be obtained. That is,
Y1 = Dtan θ1 / (tan θ1 + tan θ2)
Y2 = Dtan θ2 / (tan θ1 + tan θ2)
L = D / (tan θ1 + tan θ2)
It becomes.

  Then, for example, by using the position of the transmission antenna 11 of the interrogator 1 as a reference (for example, the origin of the position coordinates), the above-described values of Y1, Y2, and L are corrected to obtain the distance from the interrogator 1 to the responder 2. The position of the responder 2 with respect to the interrogator 1 can be estimated, and the position information of the responder 2 can be obtained.

FIG. 7 is an explanatory diagram for estimating the position information of the responder in three dimensions including the vertical direction.
In FIG. 7, as the known information, in addition to the above-described known information, the vertical transmission direction angles of the transmission antennas 11 and 12 are φ1 and φ2, respectively.
In this case, assuming that the position in the plane of the transponder obtained by correcting the position information obtained from FIG. 6 with the transmitting antenna 11 as the origin is (x1, y1), the distance in the vertical direction from the position in the plane to the transponder Should be calculated. If this vertical distance is z1,
z1 = (x1 2 + y1 2 ) 1/2 · tan φ1
As a result, the position information of the responder 2 with respect to the interrogator 1 can be obtained. The distance L ′ between the interrogator and the responder is
L = (x1 2 + y1 2 + z 2 ) 1/2
It becomes.

  As described above, in the wireless communication system of the present embodiment, the position information of the responder can be known based on the directivity information of the transmission antennas 11 and 12, in other words, the transmission direction information of the interrogation wave.

Next, FIG. 8 shows another configuration example of the responder applied to the wireless communication system of the present invention.
The responder 2 'in FIG. 8 is configured to generate a CPU operating clock when both the first interrogation wave and the second interrogation wave are received. The reception antenna 21, transmission and reception similar to the responder 2 shown in FIG. The antenna 22, the data extraction unit 23, the power supply unit 24, the CPU 25, and the modulation unit 26, and the first interrogation wave and the second interrogation wave received by the reception antenna 21 are mixed by, for example, a mixer and the operation clock of the CPU 25 The clock generation unit 27 is provided.

  In the responder 2 ', when both the first interrogation wave and the second interrogation wave are received, a clock is generated by the clock generator 27, the CPU 25 is activated, and the response data corresponding to the extracted data is modulated. The response wave is returned to the unit 26.

  Conventionally, in the configuration in which the clock is generated using the interrogation wave carrier component, the clock frequency becomes too high, so that it is necessary to separately incorporate a low-speed clock generation circuit for the CPU into the responder, and when the modulation wave component is used Requires a separate local oscillator to obtain the modulated wave component. In the configuration of FIG. 8, for example, each frequency of the first interrogation wave and the second interrogation wave is appropriately set so that the difference between the frequencies of the first interrogation wave and the second interrogation wave becomes an appropriate clock frequency for the CPU. By doing so, it is not necessary to incorporate the low-speed clock generation circuit or the local oscillator in the responder. Therefore, the cost, weight, size, thickness, etc. of the responder can be reduced.

Next, FIGS. 9 and 10 show a second embodiment of the wireless communication system of the present invention and will be described.
FIG. 9 shows a system schematic diagram of the second embodiment, and FIG. 10 shows a configuration of an interrogator 1 ′ of this embodiment.
In the interrogator 1 ′ of this embodiment, a transmission antenna 11 ′ that transmits a first interrogation wave is configured by a normal antenna with fixed directivity, and a transmission unit 14 ′ outputs an unmodulated wave interrogation wave. Except for the configuration in which the transmission unit 15 ′ outputs a modulated wave, the configuration is substantially the same as the interrogator 1 (shown in FIG. 2) of the first embodiment as shown in FIG. Then, a non-modulated first interrogator having a wide transmission area as shown by hatching in FIG. 9 is radiated from the transmission antenna 11 ′. The transmission antenna 12 scans the modulated second interrogation wave, whose directivity is variably controlled and has a transmission area much narrower than that of the first interrogation wave, including the transmission area of the first interrogation wave.

  When the transponder 2 enters the transmission area of the first interrogation wave, power is generated by the power supply unit 24 by reception of the first interrogation wave, and the CPU 25 shifts from the no-power stop mode to the standby mode, and weak radio waves or It returns its own ID information. When the second interrogation wave is received, the data extraction unit 23 extracts the data, and the CPU 25 shifts to a communication mode that outputs response data corresponding to the extracted data, and returns a response wave that includes the response data corresponding to the received data. It is the structure to do.

Next, the operation of the wireless communication system according to the second embodiment will be described with reference to FIG.
For example, consider a system in which the responder 2 passes through the first interrogation wave transmission area at high speed in the direction of the arrow in FIG. The responder 2 is a non-powered stop mode before entering the transmission area of the first interrogation wave. In this state, when the responder 2 enters the transmission area of the first interrogation wave, the first interrogation wave is received and the standby mode is set, power is generated and the CPU 25 becomes operable, and the weak radio wave or its own ID Reply information. The interrogator 1 'variably controls the directivity of the transmission antenna 12 at an extremely high speed, and scans the second interrogation wave at a high speed including the transmission area of the first interrogation wave. As a result, when the responder 2 that has entered the first interrogation wave transmission area receives the second interrogation wave that has been scanned at a high speed, the responder 2 enters the communication mode, and the interrogator 1 'receives the interrogation wave. The included data is extracted by the data extraction unit 23 and input to the CPU 25. The CPU 25 outputs response data corresponding to the input data and returns a response wave. Since the scanning speed of the second interrogation wave is extremely high, the second interrogation wave is received by the transponder 2 substantially continuously while the responder 2 exists in the transmission area of the first interrogation wave, Communication between the interrogator 1 'and the responder 2 is maintained normally and information can be exchanged. If the responder 2 passes through the first interrogation wave transmission area, the responder 2 enters the stop mode.

  According to the second embodiment, even in a system in which the responder 2 passes through the communication area of the interrogator at high speed, an expensive CPU with a fast rise time is not used, and a battery for starting up the CPU is not incorporated. In both cases, by setting a wide transmission area for the first interrogation wave, a sufficient communication time for normally communicating information can be secured. In addition, since only the responder 2 that has received the second interrogation wave returns a response wave, interference with other responders can be prevented.

  In the second embodiment described above, an adaptive array antenna is used as the receiving antenna 13 of the interrogator 1 ', and the arrival angle estimation using a conventionally known arrival angle estimation algorithm such as the MUSIC (Multiple Signal Classification) method is used. If the arrival direction of the radio wave from the responder 2 that has entered the transmission area of the first interrogation wave is estimated and the second interrogation wave is transmitted toward the estimated radio wave arrival direction, the first interrogation wave Information can be immediately communicated with the responder 2 that has entered the transmission area, a further sufficient communication time can be secured, and further, the communication between the interrogator and the responder can be speeded up. Further, in this case, since the position of the responder 2 can be grasped by estimating the arrival direction of the radio wave from the responder 2, the directivity of the transmitting antenna 12 is controlled by following the movement of the responder 2 and the second The transmission direction of the interrogation wave can be variably controlled, and the desired movement operation of the responder 2 can be tracked.

1 is a schematic diagram showing a first embodiment of a wireless communication system according to the present invention. Configuration diagram of the interrogator of the above embodiment Responder configuration diagram The flowchart explaining the operation example of 1st Embodiment. The flowchart explaining another example of operation of a 1st embodiment. Explanatory drawing when estimating the position of the transponder in two dimensions Explanatory diagram when estimating the position of the transponder in three dimensions Configuration diagram showing another configuration example of transponder Schematic which shows 2nd Embodiment of the radio | wireless communications system which concerns on this invention. Configuration diagram of the interrogator of the above embodiment Explanatory diagram of an operation example of a conventional wireless communication system 11 is a flowchart for explaining the reading operation of the responder with the ID number “0010” in the wireless communication system of FIG. 11 is a flowchart for explaining the read operation of the responder with the ID number “1111” in the wireless communication system of FIG.

Explanation of symbols

1, 1 'interrogator 2, 2' responder 3 management device 11, 11 ', 12 transmitting antenna 13 receiving antenna 17 directivity control unit 18 position information detecting unit 19 control unit 21 receiving antenna 22 transmitting / receiving antenna 23 data extracting unit 24 Power supply unit 25 CPU
26 Modulator 27 Clock Generator

Claims (9)

  1. A wireless communication system for transmitting information between an interrogator and a responder by transmitting an interrogation wave from an interrogator and returning a response wave by a responder receiving the interrogation wave,
    The interrogator includes two transmission antennas that transmit first and second interrogation waves having different frequencies, and a directivity control unit that variably controls the directivity of at least one of the two transmission antennas. A wireless communication system characterized in that communication is performed only with a responder existing at a position where the first and second interrogation waves overlap.
  2.   2. The wireless communication system according to claim 1, wherein the responder is configured to be in a response wave reply mode when receiving both the first and second interrogation waves transmitted by the interrogator.
  3.   The radio communication system according to claim 1 or 2, wherein the two transmission antennas have a configuration in which directivity can be varied by the directivity control unit.
  4.   The first interrogation wave is transmitted with the directivity of the transmission antenna fixed, while the second interrogation wave having a transmission area narrower than the first interrogation wave is variably controlled to control the directivity of the transmission antenna. The wireless communication system according to claim 1, wherein scanning is possible including a wave transmission area.
  5.   The interrogator includes a radio wave intensity measuring unit that measures the intensity of the received radio wave, and the received radio wave is determined to be a radio wave of the responder when a measurement value of the radio wave intensity measuring unit is equal to or greater than a predetermined value. The radio | wireless communications system as described in any one of Claims 1-4 comprised with the position estimation means which estimates the position of a responder based on directivity information.
  6.   The directivity of the transmitting antenna with variable directivity is sequentially variably set, and the interrogation wave from the transmitting antenna is scanned. When the measured value of the radio wave intensity measuring means exceeds a predetermined value, there is a responder. The wireless communication system according to claim 5, wherein the wireless communication system is configured to determine.
  7.   7. The configuration according to claim 1, wherein the directivity of the transmitting antenna is controlled by the directivity control unit based on position information of a specific responder given from a management device connected to the interrogator. The wireless communication system according to 1.
  8.   The wireless communication system according to claim 1, wherein the responder is configured to generate an operation clock of a built-in CPU using the first and second interrogation waves.
  9.   When the transponder enters the fixed first interrogation wave transmission area, the transponder shifts from the stop mode to the standby mode. When the transponder receives the second interrogation wave in the standby mode, the transponder enters the communication mode. The wireless communication system according to claim 4.
JP2004303997A 2004-10-19 2004-10-19 Radio communications system Pending JP2006121156A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010516149A (en) * 2007-01-16 2010-05-13 コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ Device discovery of mixed directional terminals

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010516149A (en) * 2007-01-16 2010-05-13 コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ Device discovery of mixed directional terminals

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