WO2008018254A1 - Dispositif de communication sans fil - Google Patents

Dispositif de communication sans fil Download PDF

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Publication number
WO2008018254A1
WO2008018254A1 PCT/JP2007/063118 JP2007063118W WO2008018254A1 WO 2008018254 A1 WO2008018254 A1 WO 2008018254A1 JP 2007063118 W JP2007063118 W JP 2007063118W WO 2008018254 A1 WO2008018254 A1 WO 2008018254A1
Authority
WO
WIPO (PCT)
Prior art keywords
communication
unit
reception
phase
transmission
Prior art date
Application number
PCT/JP2007/063118
Other languages
English (en)
Japanese (ja)
Inventor
Hironori Hirata
Takuya Nagai
Hideyuki Nebiya
Original Assignee
Brother Kogyo Kabushiki Kaisha
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2006220700A external-priority patent/JP2008048077A/ja
Priority claimed from JP2006220701A external-priority patent/JP4816320B2/ja
Application filed by Brother Kogyo Kabushiki Kaisha filed Critical Brother Kogyo Kabushiki Kaisha
Publication of WO2008018254A1 publication Critical patent/WO2008018254A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0617—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal for beam forming
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
    • H01Q3/26—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture
    • H01Q3/30—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture varying the relative phase between the radiating elements of an array
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/08—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
    • H04B7/0837—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using pre-detection combining
    • H04B7/0842—Weighted combining
    • H04B7/086—Weighted combining using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming

Definitions

  • the present invention relates to a wireless communication apparatus including an array antenna having a plurality of antenna elements, and more particularly to a technique for improving communication characteristics when the relative distance to a communication target is relatively short.
  • a radio communication device having a transmission unit that transmits a predetermined transmission signal from a transmission antenna and a reception unit that receives a reply signal returned in response to the transmission signal by a reception antenna.
  • an RFID (Radio Frequency Identification) system RFID tag communication device (interrogator) that reads information without contact from a small RFID tag (responder) in which predetermined information is stored.
  • This RFID system can read the information stored in the RFID tag by communicating with the RFID tag communication device even when the RFID tag is dirty or invisible. Therefore, practical use is expected in various fields such as product management and inspection processes.
  • an apparatus including an array antenna having a plurality of antenna element forces is known.
  • this is the radar device described in Patent Document 1.
  • a plurality of antenna element forces are also provided, and an array antenna having a phase shifter corresponding to each antenna element is provided.
  • Patent Document 1 Japanese Patent Laid-Open No. 6-174823
  • the phase corresponding to each antenna element is controlled, but when the relative distance to the communication target is relatively close, the radio wave between the communication target and the communication target does not become a plane wave. If the set phase difference is different from the actual phase difference of the arriving wave, there is a problem that communication characteristics are deteriorated because proper directivity control is not performed. For this reason, there has been a demand for the development of a wireless communication device that improves the communication characteristics when the relative distance to the communication target is relatively short.
  • the present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a wireless communication device that improves communication characteristics when the relative distance to a communication target is relatively short. There is to do.
  • the gist of the first invention is that an array antenna having at least three antenna elements is provided, and signals are transmitted and Z or received by the array antenna.
  • a wireless communication device that performs wireless communication with a communication target that is arranged in a predetermined relative communication direction, for each pair of antenna elements arranged at positions symmetrical with respect to a straight line indicating the communication direction.
  • a phase control unit for performing the same phase control in transmission and Z or reception.
  • the gist of the second invention is that an array antenna having at least three antenna elements is provided, and signal transmission and Z or reception are performed by the array antenna.
  • a wireless communication device that performs wireless communication with a communication target by performing a communication target position estimation unit that estimates a relative position of the communication target, and each antenna according to an estimation result by the communication target position estimation unit And a phase control unit for controlling a phase related to transmission and Z or reception in the element.
  • each pair of antenna elements arranged at a position is equipped with a phase control unit that performs the same phase control in transmission and z or reception, so that the antenna element is symmetrical with respect to the straight line indicating the communication direction. Since the phase difference from the center position of the arranged antenna elements is equal, the same phase control is performed for each pair of antenna elements, so even if the relative distance to the communication target changes, the distance It is possible to form a beam according to the conditions. That is, it is possible to provide a wireless communication device that improves communication characteristics when the relative distance to the communication target is relatively short.
  • any antenna element other than the antenna elements arranged on a straight line indicating the communication direction indicates the communication direction. It has a pair of antenna elements arranged at positions symmetrical with respect to a straight line. In this way, all antenna elements other than the antenna elements arranged on the straight line indicating the communication direction form a pair, and the same phase control is performed for each of the paired antenna elements. Even if the relative distance to the communication object changes, a beam corresponding to the distance can be formed suitably.
  • the phase control unit is configured to perform the same phase control in transmission and Z or reception for each pair of antenna elements arranged at positions symmetrical with respect to a straight line indicating the communication direction.
  • Each is provided with a single phase shift part. In this way, the same phase control can be performed in a practical manner for each pair of antenna elements.
  • the phase control unit is the most linear antenna indicating the communication direction among the pair of antenna elements disposed at a position symmetrical with respect to the straight line indicating the communication direction.
  • Each pair of antenna elements other than the pair of antenna elements disposed at a distant position is provided with a single phase shift unit for performing the same phase control in transmission and Z or reception. .
  • the same phase control can be performed in a practical manner for each pair of antenna elements, and the linear force indicating the communication direction is the most separated.
  • the configuration can be made as simple as possible by not providing a phase shift portion corresponding to the pair of antenna elements arranged at the positions.
  • the array antenna has an even number of antenna elements
  • the phase control unit is a pair of antennas arranged at positions symmetrical with respect to a straight line indicating the communication direction.
  • Each element performs the same phase control in transmission and z or reception. In this way, in a wireless communication device including an array antenna having an even number of antenna element forces, the same phase control can be performed in a practical manner for each pair of antenna elements.
  • the array antenna has an odd number of antenna elements
  • the phase control unit includes one antenna arranged on a straight line indicating the communication direction among the antenna elements.
  • the same phase control in transmission and Z or reception is performed for each pair of antenna elements arranged at positions symmetrical with respect to a straight line indicating the communication direction other than the elements.
  • the same phase control can be performed in a practical manner for each pair of antenna elements in the wireless communication apparatus provided with an array antenna having an odd number of antenna element forces.
  • the antenna elements are planar antennas disposed on the same plane.
  • the same phase control can be performed in a practical manner for each pair of antenna elements.
  • a distance setting unit that sets a predetermined relative distance to the communication target, and a direction that changes the setting of the phase control unit according to the distance set by the distance setting unit.
  • a sex control unit a distance setting unit that sets a predetermined relative distance to the communication target, and a direction that changes the setting of the phase control unit according to the distance set by the distance setting unit.
  • a sex control unit a sex control unit.
  • a distance detection unit that detects a relative distance to the communication target, and a directivity control unit that changes the setting of the phase control unit according to a detection result by the distance detection unit, It is provided.
  • a suitable beam can be formed according to the relative distance to the communication object.
  • the directivity control unit has a predetermined relational force as well as the distance detection unit.
  • the setting of the phase control unit is changed in accordance with the detection result of the above or the distance set in the distance setting unit. In this way, a suitable beam can be formed in a practical manner according to the relative distance to the communication object.
  • a table is provided that indicates a correspondence relationship between a relative distance to the communication target and a setting of the phase control unit, and the directivity control unit is configured to calculate the distance from the correspondence relationship indicated in the table.
  • the setting of the phase control unit is changed according to the detection result by the detection unit or the distance set in the distance setting unit. In this way, a suitable beam can be formed in a practical manner according to the relative distance to the communication target.
  • a signal strength detection unit that detects a signal strength of the received signal
  • the directivity control unit is configured to perform the phase control unit according to the signal strength detected by the signal strength detection unit. The setting of is changed. In this way, a suitable beam can be formed in a practical manner according to the signal strength of the received signal.
  • the antenna elements are arranged such that distances between adjacent antenna elements are equal to each other, and the phase control unit is a straight line indicating the communication direction.
  • the phase control unit is a straight line indicating the communication direction.
  • the distance detection unit detects a relative distance to the communication target based on a reception signal corresponding to the setting of the phase control unit. In this way, it is possible to easily detect the relative distance to the communication target.
  • a signal strength detection unit that detects a signal strength of the received signal is provided, and the distance detection unit is connected to the communication target based on the signal strength detected by the signal strength detection unit. The relative distance is detected. In this way, it is possible to easily detect the relative distance to the communication target in a practical manner.
  • the distance detection unit calculates a relative distance to the communication target based on a setting of the phase control unit that maximizes or minimizes the signal strength detected by the signal strength detection unit. It is to detect. In this way, the relative distance from the communication target is practically used. Can be easily detected in a specific manner.
  • a bit error rate detection unit that detects a bit error rate of the received signal
  • the distance detection unit is configured to perform communication based on the bit error rate detected by the bit error rate detection unit. Is detected. In this way, the relative distance to the communication target can be easily detected in a practical manner.
  • the distance detection unit is configured to be relative to the communication target based on a setting of the phase control unit that maximizes or minimizes the bit error rate detected by the bit error rate detection unit. The distance is detected. In this way, the relative distance to the communication target can be easily detected in a practical manner.
  • a distance detection unit that detects a relative distance to the communication target is provided, and the relative distance detected by the distance detection unit is three times the size of the array antenna.
  • phase control is performed via the phase control unit. In this way, when the phase control through the phase control unit is required, the phase control can be performed.
  • the wireless communication device transmits a predetermined transmission signal toward a wireless tag that is a communication target, and transmits a reply signal returned from the wireless tag in response to the transmission signal.
  • the wireless tag communication device performs communication of information with the wireless tag by receiving. In this way, it is possible to provide a wireless tag communication device that improves communication characteristics when the distance from the wireless tag is relatively short.
  • a communication target position estimation unit that estimates the relative position of the communication target, and transmission and Z in each antenna element according to an estimation result by the communication target position estimation unit
  • a phase control unit that controls the phase related to reception, and by controlling the phase corresponding to each antenna element according to the relative distance and Z or relative direction of the communication target, Even if the relative distance between the two is relatively close, the phase synthesis can be suitably performed and the communication accuracy can be improved. That is, it is possible to provide a wireless communication device that improves communication characteristics when the relative distance to the communication target is relatively short.
  • the phase corresponding to each antenna element is set to a suitable value by simple control as compared with the well-known AAA (Adapted Array Antenna) processing. IJ point is that the time required for communication can be shortened.
  • the communication target position estimation unit includes a signal strength detection unit that detects a signal strength of a received signal received by at least one of the antenna elements. Is to estimate the relative position of the communication target based on the detection result by the signal intensity detection unit. In this way, the relative position of the communication target can be estimated in a practical manner.
  • a table is provided that indicates a correspondence relationship between the relative position of the communication target and a phase related to transmission and Z or reception in each antenna element, and the phase control unit includes the correspondence relationship indicated in the table. From this, the phase related to transmission and Z or reception in each antenna element is controlled based on the estimation result by the communication target position estimation unit. In this way, the phase corresponding to each antenna element can be set to a suitable value in a practical manner.
  • the table includes a first linear coordinate and a relative position of the communication target with respect to a second linear coordinate orthogonal to the first linear coordinate, and transmission and Z or reception at each antenna element.
  • the phase corresponding to each antenna element can be set to a suitable value in a relatively highly accurate and practical manner.
  • the table shows a correspondence relationship between a relative distance to the communication target and a relative direction of the communication target and a phase related to transmission and Z or reception in each antenna element.
  • the phase corresponding to each antenna element can be set to a suitable value in a simple and practical manner.
  • the communication target position estimation unit applies the correspondence relationships shown in the table when performing phase control related to transmission and Z or reception in each antenna element, and is detected by the signal strength detection unit. Corresponding power having the maximum value as a result is to estimate the relative distance and relative direction of the communication target, and the phase control unit Based on the relative distance and the relative direction estimated by the communication target position estimation unit, the phase related to transmission and Z or reception in each antenna element is controlled. In this way, the phase corresponding to each antenna element can be set to a suitable value in a relatively high accuracy and practical manner.
  • the communication target position estimation unit estimates a relative distance of the communication target with respect to a detection result force by the signal strength detection unit regarding a reception signal received by one antenna element
  • the phase control unit applies the correspondence relationship shown in the table corresponding to the relative distance estimated by the communication target position estimation unit, and the correspondence relationship in which the detection result by the signal strength detection unit takes the maximum value. Is applied to phase control related to transmission and Z or reception in each antenna element. In this way, the phase corresponding to each antenna element can be set to a suitable value in a simple and practical manner.
  • the communication target position estimation unit estimates a detection result force of the signal intensity detection unit regarding a reception signal sequentially received by two antenna elements, and a relative distance and a relative direction of the communication target.
  • the phase control unit controls a phase related to transmission and Z or reception in each antenna element based on the relative distance and the relative direction estimated from the table by the communication target position estimation unit. In this way, the phase corresponding to each antenna element can be set to a suitable value in a simple and practical manner.
  • the relative position of the communication target with respect to the first linear coordinate and the second linear coordinate orthogonal to the first linear coordinate and the phase regarding transmission and Z or reception at each antenna element is also known as a second table indicating the correspondence between the relative distance to the communication target and the relative direction of the communication target and the phase related to transmission and Z or reception at each antenna element.
  • the communication target position estimation unit estimates a relative distance of the communication target based on a detection result by the signal strength detection unit, and the phase control unit includes the communication target position estimation unit.
  • phase related to transmission and Z or reception in each antenna element is controlled from the correspondence shown in the first table, and the communication pair
  • the phase relating to transmission and Z or reception in each antenna element is controlled from the correspondence shown in the second table.
  • the wireless communication device transmits a predetermined transmission signal toward a wireless tag that is a communication target, and transmits a reply signal returned from the wireless tag in response to the transmission signal.
  • the wireless tag communication device performs communication of information with the wireless tag by receiving. In this way, it is possible to provide a wireless tag communication device that improves communication characteristics when the distance from the wireless tag is relatively short.
  • FIG. 1 is a diagram for explaining a wireless tag communication system in which a wireless communication apparatus of the present invention is preferably used.
  • FIG. 2 is a diagram for explaining the configuration of a wireless tag communication device which is an embodiment of the wireless communication device of the first invention.
  • FIG. 3 is a diagram illustrating a configuration of a wireless tag circuit element provided in a wireless tag that is a communication target of the wireless tag communication device in FIG. 2.
  • FIG. 4 is a diagram for explaining directivity control by a conventional array antenna having a plurality of antenna elements.
  • FIG. 5 is a diagram for explaining a phase difference caused by a difference in distance between each antenna element provided in the array antenna of FIG. 4 and a communication target.
  • FIG. 6 is a diagram for explaining directivity control by an array antenna provided in the RFID tag communication apparatus of FIG.
  • FIG. 7 is a diagram illustrating directivity control by another array antenna provided in the RFID tag communication apparatus of FIG. 2.
  • FIG. 8 is an example of a correspondence relationship between the relative distance to the communication target wireless tag and the setting of the phase control unit stored in the RAM or the like of the control unit provided in the wireless tag communication device of FIG. It is a figure explaining one bull.
  • FIG. 9 An array of five rod-shaped antenna element forces arranged so as to be parallel to each other in the same plane and so that the distances between adjacent antenna elements are all equal ⁇ 2.
  • 6 is a graph showing the relationship between the relative distance of a communication target in an antenna and the amplitude of a transmission signal or reception signal with 1 at infinity.
  • FIG. 10 is a flowchart for explaining a main part of an example of communication control with the wireless tag by the control unit of the wireless tag communication device of FIG. 2, in which the relative distance of the wireless tag is set in advance by the tag distance setting unit. Is what is executed.
  • FIG. 11 is a flowchart for explaining a main part of another example of communication control with the wireless tag by the control unit of the wireless tag communication device of FIG. 2, in the case of detecting the relative distance to the wireless tag during communication. This is executed when a table in which the phases of antenna elements adjacent to each other are set in phase is used.
  • FIG. 12 is a flowchart for explaining a main part of another example of communication control with the wireless tag by the control unit of the wireless tag communication device in FIG. 2, in which a relative distance to the wireless tag is detected during communication. This is executed when a table in which the phases of antenna elements adjacent to each other are set in phase is used.
  • FIG. 13 is a flowchart for explaining a main part of another example of communication control with the wireless tag by the control unit of the wireless tag communication device of FIG. 2, in the case of detecting the relative distance to the wireless tag during communication. This is executed when using tables in which the phases of antenna elements adjacent to each other are set to opposite phases.
  • FIG. 14 is a flowchart for explaining a main part of another example of communication control with the wireless tag by the control unit of the wireless tag communication device of FIG. 2, in which a relative distance to the wireless tag is detected during communication. This is executed when using tables in which the phases of antenna elements adjacent to each other are set to opposite phases.
  • FIG. 15 is a diagram for explaining the configuration of a wireless tag communication device that is an embodiment of the wireless communication device of the first invention.
  • FIG. 16 is a diagram for explaining a configuration of a two-dimensional array antenna to which the first invention is preferably applied.
  • FIG. 17 is a diagram for explaining the configuration of a wireless tag communication device which is an embodiment of the wireless communication device of the second invention.
  • FIG. 18 is a diagram for explaining a relative positional relationship between an array antenna provided in the wireless tag communication device of FIG. 17 and a wireless tag that is a communication target thereof.
  • the RFID tag relative to the X-coordinate, which is the first linear coordinate, and the y-coordinate, which is the second linear coordinate orthogonal to the first linear coordinate, provided in the wireless tag communication apparatus of FIG. 3 is an xy coordinate table as a first table showing a correspondence relationship between a position and a phase related to transmission and Z or reception in each antenna element.
  • 20 is a second diagram showing the correspondence between the relative distance to the RFID tag and the relative direction of the RFID tag and the phase related to transmission and Z or reception at each antenna element, which is provided in the RFID tag communication apparatus of FIG. It is an r- ⁇ coordinate table as a table.
  • FIG. 21 is a flowchart for explaining an example of reception phase control by the control unit of the RFID tag communication apparatus of FIG.
  • FIG. 22 is a flowchart illustrating another example of reception phase control by the control unit of the wireless tag communication device in FIG. 17.
  • FIG. 23 is a flowchart illustrating still another example of reception phase control by the control unit of the RFID tag communication apparatus of FIG.
  • FIG. 24 is a flowchart for explaining yet another example of reception phase control by the control unit of the RFID tag communication apparatus of FIG.
  • FIG. 1 is a diagram for explaining a radio tag communication system 10 in which the radio communication apparatus of the first invention is preferably used.
  • the RFID tag communication system 10 includes an RFID tag communication device 12 which is an embodiment of the RFID communication device according to the first aspect of the present invention, and a single or a plurality of communication targets of the RFID tag communication device 12 (single in FIG. 1). )
  • the RFID tag communication device 12 functions as an interrogator of the RFID system, and the RFID tag 14 functions as a responder. That is, when the interrogation wave F (transmission signal) is transmitted from the radio tag communication apparatus 12 toward the radio tag 14, the radio tag 14 that has received the interrogation wave F uses a predetermined command (transmission data).
  • the interrogation wave F is modulated and sent back as a response wave F (reply signal) to the RFID tag communication device 12 so that information communication between the RFID tag communication device 12 and the wireless tag 14 is possible.
  • the wireless tag communication system 10 is used, for example, for management of articles in a predetermined communication area.
  • the wireless tag 14 is preferably attached to an article to be managed, for example. It is provided integrally with the article.
  • FIG. 2 is a diagram for explaining the configuration of the RFID tag communication apparatus 12. As shown in FIG. 2, the RFID tag communication apparatus 12 of the present embodiment includes a main carrier generator 18 for generating a main carrier of the transmission signal, and a main carrier generated by the main carrier generator 18.
  • a transmission signal modulation unit 20 that modulates a carrier wave with a transmission information signal (transmission data) generated by a transmission data generation unit 42 (to be described later) to generate the transmission signal, and a transmission signal modulated by the transmission signal modulation unit 20
  • 30b, 30c, 30d (hereinafter simply referred to as antenna element 30 unless otherwise distinguished) controls the transmission directivity of the transmission signals transmitted from the plurality of antenna elements 30 and combines them.
  • the phase control unit 22 (hereinafter simply referred to as the combining unit 25 unless otherwise distinguished from the combining unit 25a), and a local signal having a predetermined frequency is supplied.
  • Generated local Multiple down converters 28a and 28b that downconvert by multiplying the local signal generated by the local oscillator 26 with each of the received signals supplied from the oscillator 26 and the phase control unit 22 (two in FIG. 2) (Hereinafter referred to simply as “down converter 28” unless otherwise specified) and control the operation of the RFID tag communication device 12 including the demodulation processing of the received signal down-converted by the down converter 28 Part 40.
  • the array antenna 16 is composed of the plurality of antenna elements 30.
  • a circuit coupler or a directional coupler is preferably used as the transmission / reception separating unit 24.
  • the phase control unit 22 determines the phase of the transmission signal supplied from the transmission signal modulation unit 20.
  • a transmission phase shifter 32a that controls and supplies the antenna elements 30a and 30d and a transmission phase shifter that controls the phase of the transmission signal supplied from the transmission signal modulation unit 20 and supplies the phase to the antenna elements 30b and 30c.
  • 32b (hereinafter simply referred to as the transmission phase shifter 32 unless otherwise distinguished from the transmission phase shifter 32a).
  • the radio tag 14 to be communicated is arranged.
  • the same phase control in transmission is performed for each pair of antenna elements 30a and 30d, 30b and 30c arranged at positions symmetrical with respect to a straight line indicating a predetermined communication direction.
  • a received phase shifter 34a that controls the phase of the received signal corresponding to the antenna elements 30a and 30d and supplies the resultant signal to the downconverter 28a, and the combined unit 25b.
  • Received phase shifter 34b that controls the phase of the received signal corresponding to the antenna elements 30b and 30c and supplies it to the down-compressor 28b (hereinafter particularly distinguished from the received phase shifter 34a). If not, it is simply referred to as a reception phase shifter 34), and a pair of antenna elements 30a and 30d, 30b and 30b arranged at positions symmetrical with respect to the straight line indicating the communication direction. The same phase control for reception is performed every 3 Oc.
  • a transmission amplification unit that amplifies a signal for each pair of antenna elements 30 disposed at a position symmetrical with respect to the straight line indicating the communication direction, and A reception amplification unit may be provided.
  • the control unit 40 includes a CPU, a ROM, a RAM, and the like, and is a so-called microcomputer that performs signal processing according to a program stored in advance in the ROM while using a temporary storage function of the RAM.
  • Generation of the transmission data, determination of the control amount (phase shift amount) of the transmission phase shifter 32 and the reception phase shifter 34, transmission control for transmitting the transmission signal toward the wireless tag 14, and the transmission signal thereof In response to this, reception control for receiving a reply signal returned from the wireless tag 14 and demodulation control for demodulating the received signal are executed.
  • the transmission data generation unit 42, the PAA weight control unit 44, the reception signal synthesis unit 50, the reception signal demodulation unit 52, the signal strength detection unit 54, the tag distance setting unit 56, the bit error rate detection Unit 58 (hereinafter referred to as BER detection unit 58) and tag distance detection unit 60 are provided functionally.
  • the transmission data generation unit 42 is a carrier generated by the main carrier generation unit 18. Transmission data to be transmitted to the wireless tag 14 on the wave is generated and supplied to the transmission signal modulator 20. In the transmission signal modulation unit 20, modulation is performed based on the transmission data supplied from the transmission data generation unit 42 to obtain a transmission signal, which is transmitted from the antenna element 30 via the phase control unit 22 and the like.
  • the PAA weight control unit 44 includes a transmission control unit 46 and a reception control unit 48, and controls transmission directivity by controlling the phase of each transmission signal transmitted from the plurality of antenna elements 30.
  • the reception directivity is controlled by controlling the phase of each reception signal received by the plurality of antenna elements 30. That is, it functions as a directivity control unit that controls the transmission directivity and the reception directivity of the array antenna 16 by changing the setting of the phase control unit 22.
  • the transmission control unit 46 controls the phase of the transmission signal transmitted from the antenna element 30 via the transmission phase shift unit 32 in the phase control unit 22. Specifically, the phase of the transmission signal transmitted from the pair of antenna elements 30a and 30d is controlled via the transmission phase shifter 32a, and the pair is paired via the transmission phase shifter 32b. Controls the phase of the transmission signal transmitted from the antenna elements 30b and 30c.
  • the reception control unit 48 controls the phase of the reception signal received by the antenna element 30 via the reception phase shift unit 34 in the phase control unit 22. Specifically, the phase of the received signal received by the pair of antenna elements 30a and 30d via the receiving phase shifter 34a, that is, the synthesized signal synthesized by the multiplexer 25a, is controlled, and The phase of the received signal received by the pair of antenna elements 30b and 30c via the reception phase shifter 34b, that is, the synthesized signal synthesized by the multiplexer 25b is controlled.
  • the reception signal combining unit 50 combines (adds) the reception signals respectively received by the plurality of antenna elements 30. Further, the reception signals respectively received by at least two antenna elements 30 selected from the plurality of antenna elements 30 are combined. That is, in the RFID tag communication apparatus 12 of the present embodiment, the phase of the received signal received by at least two antenna elements 30 selected from the plurality of antenna elements 30 is input to the phase control unit 22. The received signals are controlled by the received signals. The signal intensity is synthesized by the signal synthesis unit 50, and the signal intensity of the synthesized signal can be detected by the signal intensity detection unit 54.
  • the received signal demodulating unit 52 demodulates the received signals from the plurality of antenna elements 30 synthesized by the received signal synthesizing unit 50.
  • the demodulated signal is FM-decoded to read an information signal related to the modulation by the wireless tag 14.
  • the signal strength detection unit 54 detects the signal strength of the received signal received by at least one antenna element 30 among the plurality of antenna elements 30. Further, the signal strength of the synthesized signal synthesized by the received signal synthesis unit 50 is detected. That is, the signal strength of the combined signal of the received signals received by at least two antenna elements 30 selected from among the plurality of antenna elements 30 is detected.
  • the tag distance setting unit 56 sets a predetermined relative distance from the wireless tag 14.
  • the wireless tag communication device 12 of this embodiment performs wireless communication with the wireless tag 14 arranged in a predetermined relative communication direction, and the tag distance setting unit 56
  • the relative distance to the tag 14 is determined in advance, for example, the relative distance input by an input device (not shown) is set.
  • the relative distance as the detection result is set.
  • the PAA weight control unit 44 changes the setting of the phase control unit 22 according to the distance set by the tag distance setting unit 56. The change of such setting will be described later.
  • the BER detection unit 58 detects a bit error rate of a received signal received by at least one antenna element 30 among the plurality of antenna elements 30. That is, the ratio (ratio) that the bits constituting the code included in the received signal demodulated by the received signal demodulating unit 52 cannot be read correctly is detected. Further, the bit error rate of the synthesized signal synthesized by the received signal synthesis unit 50 is detected. That is, the bit error rate of the combined signal of the received signals received by at least two antenna elements 30 selected from among the plurality of antenna elements 30 is detected.
  • the tag distance detection unit 60 detects a relative distance from the wireless tag 14 that is a communication target. To do. That is, the relative distance to the radio tag 14 is detected based on the received signal corresponding to the setting of the phase control unit 22. Preferably, based on the signal strength detected by the signal strength detector 54, the wireless tag is set based on the setting of the phase controller 22 that maximizes or minimizes the signal strength detected by the signal strength detector 54. Detect the relative distance from 14. Preferably, based on the bit error rate detected by the BET detection unit 58, based on the setting of the phase control unit 22 that maximizes or minimizes the bit error rate! The relative distance of is detected.
  • the PAA weight control unit 44 changes the setting of the phase control unit 22 according to the distance detected by the tag distance detection unit 60. The change of the setting will be described later.
  • FIG. 3 is a diagram for explaining the configuration of the RFID circuit element 62 provided in the RFID tag 14.
  • the RFID circuit element 62 has an antenna unit 64 for transmitting / receiving a signal to / from the RFID tag communication device 12 and a signal received by the antenna unit 64.
  • an IC circuit section 66 for performing the above operation.
  • the IC circuit unit 66 stores the energy of the interrogation wave F rectified by the rectification unit 68 and the rectification unit 68 that rectifies the interrogation wave F received from the RFID tag communication device 12 received by the antenna unit 64.
  • Power supply unit 70 a carrier wave force received by the antenna unit 64, a clock extraction unit 72 that extracts a clock signal and supplies the clock signal to the control unit 78, and a memory that functions as an information storage unit that can store a predetermined information signal Unit 74, modulation / demodulation unit 76 connected to the antenna unit 64 to modulate and demodulate signals, the RFID circuit element 62 via the rectification unit 68, clock extraction unit 72, modulation / demodulation unit 76, etc. And a control unit 78 for controlling the operation of the apparatus.
  • the control unit 78 performs control to store the predetermined information in the memory unit 74 by communicating with the RFID tag communication device 12, and the modulation / demodulation of the interrogation wave F received from the antenna unit 64.
  • the unit 76 Based on the information signal stored in the memory unit 74, the unit 76 performs basic control such as control for reflecting and returning the response wave F as a response wave F from the antenna unit 64.
  • FIG. 4 is a diagram for explaining directivity control by a conventional array antenna 80 having a plurality of antenna elements 82.
  • the array antenna 80 includes a plurality of antennas (four in FIG. 4) for transmitting and / or receiving signals to / from the communication target.
  • Elements 82a, 82b, 82c, 82d (hereinafter simply referred to as antenna elements 82 unless otherwise distinguished) are arranged so that the distances between adjacent antenna elements 82 are equal.
  • phase shift portions 84a, 84b, 84c, 84d (hereinafter simply referred to as phase shift portion 84 unless otherwise distinguished) are provided corresponding to each antenna element 82, and the plurality of phase shift portions are provided.
  • the directivity of the array antenna 80 is determined by controlling the phase of the transmission signal or reception signal corresponding to each antenna element 82 by 84.
  • the directivity of the array antenna 80 composed of a plurality of antenna elements 82 arranged at equal intervals in this way is directed in the central direction indicated by the broken-line arrows in FIG.
  • the phase corresponding to each antenna element 82 is adjusted by the same angle for all antenna elements 82.
  • the communication target such as the wireless tag 14 is located at a relatively short distance
  • the communication target and each antenna are increased as the distance of the linear force indicating the center direction increases.
  • a distance difference L2 — L1 is generated between the distance L1 between the elements 82b and 82c and the communication target, and the distance L2 between the antennas 82a and 82d disposed at a relatively far position and the communication target.
  • FIG. 6 is a diagram for explaining directivity control by the array antenna 16 provided in the RFID tag communication apparatus 12 of the present embodiment.
  • the antenna element 30 provided in the array antenna 16 is a rod-shaped (straight) element such as a monopole antenna or a dipole antenna.
  • a rod-shaped (straight) element such as a monopole antenna or a dipole antenna.
  • the distances between adjacent antenna elements 30 are equal to each other. That is, the distance between the antenna elements 30a and 30b, the distance between the antenna elements 30b and 30c, and the distance between the antenna elements 30c and 30d are all equal distances k.
  • the communication direction of the array antenna 16 is perpendicular to the plane on which the plurality of antenna elements 30 are arranged and the arrangement width direction of the antenna elements 30 as shown by broken line arrows in FIG. This is the direction indicated by the straight line passing through the center.
  • any of the antenna elements 30 other than the antenna elements arranged on a straight line indicating the communication direction has the communication direction. It has a pair of antenna elements 30 arranged at positions symmetrical with respect to the straight line shown. That is, as shown in FIG.
  • the antenna elements 30a and 30d and the antenna elements 30b and 30c are arranged at symmetrical positions with respect to a straight line indicating the communication direction, and the antenna elements 30a and 30d Antenna elements 30b and 30c form a pair.
  • transmission phase shift units 32a and 32b for performing phase control in transmission corresponding to the antenna elements 30a and 30d and the antenna elements 30b and 30c, respectively, and phase control in reception as described above.
  • Receive phase shifters 34a and 34b are provided for each pair.
  • a pair of antenna elements arranged at positions symmetrical with respect to the straight line indicating the communication direction via the transmission phase shift units 32a and 32b and the reception phase shift units 34a and 34b.
  • the same phase control in transmission and Z or reception is performed every 30a and 30d, 30b and 30c.
  • the amount of phase shift increases as the distance from the straight line indicating the communication direction increases.
  • the same phase control in transmission and Z or reception is performed so as to be doubled.
  • even number of antenna elements 30 have antenna elements 30 as a pair, and are arranged at positions symmetrical with respect to a straight line indicating the communication direction.
  • the antenna element 30 is not arranged on the straight line shown, but in the array antenna having an odd number of antenna elements, the antenna element located at the center is arranged on the straight line showing the communication direction, and the antenna Only the elements do not have a pair of antenna elements.
  • the plurality of antenna elements 30 provided in the array antenna 16 do not necessarily have to be arranged such that the distances between the antenna elements 30 adjacent to each other are equal to each other.
  • the distance between the antenna elements 30a and 30b is m
  • the distance between the antenna elements 30b and 30c is n
  • the distance between the antenna elements 30c and 30d is m. There may be.
  • the antenna elements 30a and 30d and the antenna elements 30b and 30c with respect to a straight line indicating the communication direction. Are arranged in symmetrical positions, and the same phase control in transmission and Z or reception is performed for each of the antenna elements 30a and 30d and the antenna elements 30b and 30c as a pair. .
  • the transmission directivity and the reception directivity of the array antenna 16 of the present embodiment configured as described above are controlled by the PAA weight control unit 44 as a directivity control unit.
  • the PAA weight control unit 44 preferably uses the phase control unit 22 according to a detection result by the tag distance detection unit 60 or a distance set in the tag distance setting unit 56 from a predetermined relationship.
  • the phase shift amount of each of the transmission phase shifter 32 and the reception phase shifter 34 is changed.
  • FIG. 8 is a diagram for explaining a table 86 that is an example of a correspondence relationship between the relative distance L to the communication target wireless tag 14 and the setting of the phase control unit 22 that is stored in the RAM or the like of the control unit 40. It is. As shown in FIG.
  • the table 86 has transmission phase shifters 32a and 32b or reception phase shifters in the phase controller 22 corresponding to the relative distance L [m] to the wireless tag 14.
  • the amount of phase shift [deg] for each of parts 34a and 34b is determined.
  • the PAA weight control unit 44 preferably matches the phase according to the detection result by the tag distance detection unit 60 or the distance set by the tag distance setting unit 56 from the correspondence relationship shown in the table 86. Change the setting of the control unit 22.
  • the antenna elements 30 adjacent to each other are preferably set so that the phases thereof are the same or opposite. The difference in control according to such settings will be described later with reference to the flowcharts of FIGS. 11 to 14.
  • the PAA weight control unit 44 preferably has a relative distance to the wireless tag 14 set by the tag distance setting unit 56 or the wireless tag detected by the tag distance detection unit 60.
  • the relative distance to 14 is not more than 3 times the dimension of the array antenna 16
  • phase control is performed via the phase control unit 22, while when the relative distance is greater than 3 times, the phase control unit 22 is used.
  • the phase control via is not performed.
  • the dimension of the array antenna 16 is a dimension in the arrangement width direction of the plurality of antenna elements 30 constituting the array antenna 16, and is 3k in the example shown in FIG. 6 and 2m + in the example shown in FIG. n.
  • 9 shows an array antenna consisting of five rod-shaped antenna element forces arranged parallel to each other in the same plane and so that the distances between adjacent antenna elements are all equal to ⁇ 2.
  • 10 is a graph showing the relationship between the relative distance (horizontal axis) of a communication target and the amplitude of a transmission signal or reception signal (vertical axis) where infinity is 1 in a tena. This graph shows that when there is a communication target at infinity on the center axis of the array antenna, phased array control is performed so that the transmission / reception strength to the communication target from the array antenna is maximized. It shows that the transmission / reception strength decreases as the distance decreases.
  • the size of an array antenna with five antenna elements arranged in the above relative position is 2 ⁇ , and the force of 3 ⁇ is 6 ⁇ .
  • the relative distance of the communication target is 6
  • the transmission / reception amplitude hardly changes
  • the relative distance force S decreases gradually. That is, when the relative distance with the communication target is 6 ⁇ or less, which is three times the size of the array antenna, the relative control with the communication target is performed by performing phase control via the phase control unit 22.
  • the effect of the first invention for improving the communication characteristics in a relatively close case can be obtained, and when the relative distance is larger than 6 ⁇ , there is no need to perform such control, so that control is omitted. This makes processing easy.
  • FIG. 10 is a flowchart for explaining a main part of an example of communication control with the wireless tag 14 by the control unit 40 of the wireless tag communication device 12, and is repeatedly executed at a predetermined cycle. .
  • the control shown in FIG. 10 is executed when the relative distance of the wireless tag 14 is set in advance by the tag distance setting unit 56.
  • step (hereinafter, step is omitted) SA1 corresponding to the operation of the heel weight control unit 44 a preset relative distance of the wireless tag 14 is read out,
  • the set value table of the phase shifter that is, the table 86 is referred to, and the phase shift amount corresponding to the relative distance of the wireless tag 14 is read, and the transmission phase shift unit 32 and the ⁇ or reception shift in the phase control unit 22 are read out. Applies to phase 34.
  • step S 2 information is transmitted to and received from the wireless tag 14 via the phase control unit 22 set in SA 1, and then this routine is terminated.
  • FIG. 11 is a flowchart for explaining a main part of another example of communication control with the wireless tag 14 by the control unit 40 of the wireless tag communication device 12, which is repeatedly executed at a predetermined cycle. It is. Note that the control shown in FIG. 11 performs communication with the wireless tag 14 during communication. This is performed when a relative distance is detected (measured) and the table 86 in which the phases of the antenna elements 30 adjacent to each other are set in phase is used.
  • the phase shifter setting value table that is, the table 86 is referred to, and the phase shift amount when the relative distance of the wireless tag 14 is set to infinity is read.
  • the transmission phase shifter 32 and Z or the reception phase shifter 34 in the phase controller 22.
  • SB2 information is transmitted / received to / from the wireless tag 14 via the phase control unit 22 set in SB1.
  • SB3 the signal strength of the received signal received by the array antenna 16 is detected and stored in the RAM or the like of the control unit 40.
  • SB4 the table 86 is referred to, and the phase shift amount when the relative distance of the wireless tag 14 is set to a value one step lower than the set value at that time is read out, and the phase control unit Applies to transmit phase shifter 32 and Z or receive phase shifter 34 at 22.
  • SB5 information is transmitted / received to / from the wireless tag 14 via the phase control unit 22 set in SB4.
  • SB 6 the signal strength of the received signal received by the array antenna 16 is detected, and whether or not the signal strength is larger than the signal strength of the received signal detected and stored in the previous communication. To be judged.
  • SB6 When the determination of SB6 is affirmed, V is stored in SB7, and the signal strength of the new received signal that is the object of determination of SB6 is stored in the RAM of the control unit 40.
  • the determination of the force SB6 to execute the following processing again is denied, the relative distance L of the wireless tag 14 at that time in SB8 corresponding to the operation of the tag distance setting unit 56 is the control unit 40 This routine is terminated after it is stored in the RAM.
  • SB1 and SB4 correspond to the operation of the PAA weight control unit 44
  • SB3 and SB6 correspond to the operation of the signal strength detection unit 54
  • SB1 to SB7 correspond to the operation of the tag distance detection unit 60, respectively. .
  • FIG. 12 is a flowchart for explaining a main part of still another example of communication control with the wireless tag 14 by the control unit 40 of the wireless tag communication device 12, which is repeatedly executed at a predetermined cycle.
  • the control shown in FIG. 12 is for detecting (measuring) the relative distance from the wireless tag 14 during communication, and a table 86 in which the phases of the antenna elements 30 adjacent to each other are set in phase. It is executed when used.
  • the phase shifter setting value table that is, the table 86 is referred to, and the phase shift amount when the relative distance of the wireless tag 14 is set to infinity is read.
  • SC2 information is transmitted to and received from the wireless tag 14 via the phase control unit 22 set in SC1.
  • SC3 the bit error rate of the received signal received by the array antenna 16 is detected and stored in the RAM or the like of the control unit 40.
  • SC4 the table 86 is referred to, and the phase shift amount when the relative distance of the wireless tag 14 is set to a value lower by one step than the set value at that time is read, and the phase control unit Applies to transmit phase shifter 32 and Z or receive phase shifter 34 at 22.
  • SC5 information is transmitted / received to / from the wireless tag 14 via the phase control unit 22 set in SC4.
  • SC6 the bit error rate of the received signal received by the array antenna 16 is detected, and whether or not the bit error rate is smaller than the bit error rate of the received signal detected and stored in the previous communication. Is judged. If the determination of SC6 is affirmative, after SC7 stores the bit error rate of the new received signal subject to the determination of SC6 in the RAM or the like of the control unit 40, the processing below SC4 is performed. When the determination of SC6 is negative, the relative distance of the wireless tag 14 at that time is determined by the RAM of the control unit 40 or the like in SC8 corresponding to the operation of the tag distance setting unit 56. After being stored in this routine, this routine is terminated.
  • SC1 and SC4 correspond to the operation of the PAA weight control unit 44
  • SC3 and SC6 correspond to the operation of the BER detection unit 58
  • SC1 to SC7 correspond to the operation of the tag distance detection unit 60, respectively.
  • FIG. 13 is a flowchart for explaining a main part of still another example of communication control with the wireless tag 14 by the control unit 40 of the wireless tag communication device 12, which is repeatedly executed at a predetermined cycle.
  • the control shown in FIG. 13 is for detecting (measuring) the relative distance from the wireless tag 14 during communication, and is a table in which the phases of the antenna elements 30 adjacent to each other are set to opposite phases. It is executed when using.
  • the steps common to the control of FIG. 11 described above are the same. Reference numerals are assigned and explanations thereof are omitted.
  • the signal strength of the received signal received by the array antenna 16 is detected in SB9 following the processing of SB5 described above, and the signal strength is detected and stored in the previous communication. It is determined whether or not the received signal strength is greater than the received signal strength. If the determination of SB9 is denied, the processing of SB4 and subsequent steps is executed again after the processing of SB7 described above. However, if the determination of SB9 is affirmed, SB8 described above is executed. After the above process is executed, this routine is terminated.
  • FIG. 14 is a flowchart for explaining a main part of still another example of communication control with the wireless tag 14 by the control unit 40 of the wireless tag communication device 12, and is repeatedly executed at a predetermined cycle.
  • the control shown in FIG. 14 is for detecting (measuring) the relative distance from the wireless tag 14 during communication, and is a table in which the phases of the antenna elements 30 adjacent to each other are set to opposite phases. It is executed when using. Further, in the control of FIG. 14, steps common to the control of FIG. 12 described above are denoted by the same reference numerals and description thereof is omitted.
  • the bit error rate of the received signal received by the array antenna 16 is detected in SC9 following the process of SC5 described above, and the bit error rate is detected and stored in the previous communication. It is determined whether the bit error rate of the received signal is smaller. If the determination of SC9 is negative, the above-mentioned SC7 processing is executed, and then the power to execute the processing below SC4 again. If the determination of SC9 is positive, the above-mentioned SC8 processing is performed. Is executed, the routine is terminated.
  • the same phase control in transmission and Z or reception is performed for each pair of antenna elements 30 arranged at positions symmetrical with respect to the straight line indicating the communication direction. Since the phase control unit 22 is provided, the phase difference of the center position force is equal for the pair of antenna elements 30 arranged at positions symmetrical with respect to the straight line indicating the communication direction.
  • a beam corresponding to the distance can be formed even if the relative distance to the wireless tag 14 that is a communication target changes. That is, it is possible to provide the wireless tag communication device 12 that improves the communication characteristics when the relative distance to the communication target is relatively short.
  • the phase shift portions 84 are provided corresponding to the antenna elements 82 constituting the array antenna 80, and the phase control is performed via each phase shift portion 84.
  • the antenna elements 30 other than the antenna elements 30 arranged on the straight line indicating the communication direction are all in positions symmetrical with respect to the straight line indicating the communication direction. Since the antenna elements 30 are arranged as a pair, all the antenna elements 30 other than the antenna elements 30 arranged on the straight line indicating the communication direction constitute a pair and become the pair. By performing the same phase control for each antenna element 30, a beam corresponding to the distance can be suitably formed even if the relative distance to the communication target changes.
  • phase control unit 22 is a single unit for performing the same phase control in transmission for each pair of antenna elements 30 disposed at positions symmetrical with respect to the straight line indicating the communication direction.
  • Transmission phase shifter 32 and a single reception phase shifter 34 for performing the same phase control in reception, each of the paired antenna elements 30 has a practical aspect. Thus, the same phase control can be performed.
  • the array antenna 16 has an even number of antenna elements 30, and the phase control unit 22 is a pair of antenna elements arranged at positions symmetrical with respect to a straight line indicating the communication direction. Since the same phase control in transmission and Z or reception is performed every 30, in a wireless communication apparatus having an array antenna 16 composed of an even number of antenna elements 30, it is practical for each antenna element 30 in the pair. In this manner, the same phase control can be performed.
  • a tag distance setting unit 56 that sets a predetermined relative distance from the wireless tag 14.
  • SB8 and PAA weight control unit 44 as a directivity control unit that changes the setting of the phase control unit 22 according to the distance set by the tag distance setting unit 56 , SC1, SC4), a suitable beam can be formed according to the relative distance to the wireless tag 14.
  • a tag distance detection unit 60 (SB1 to SB7, SC1 to SC7) for detecting a relative distance to the wireless tag 14, and the phase control according to a detection result by the tag distance detection unit 60 Since a PAA weight control unit 44 as a directivity control unit that changes the setting of the unit 22 is provided, a suitable beam can be formed according to the relative distance from the wireless tag 14.
  • the PAA weight control unit 44 determines whether the phase control unit 22 has a predetermined relationship according to a detection result from the tag distance detection unit 60 or a distance set in the tag distance setting unit 56. Since the setting is changed, a suitable beam can be formed in a practical manner according to the relative distance from the wireless tag 14.
  • a table 86 indicating a correspondence relationship between the relative distance to the wireless tag 14 and the setting of the phase control unit 22 is provided, and the directivity control unit 22 has the tag based on the correspondence relationship shown in the table 86. Since the setting of the phase control unit 22 is changed in accordance with the detection result by the distance detection unit 60 or the distance set in the tag distance setting unit 56, depending on the relative distance to the radio tag 14. A suitable beam can be formed in a practical manner.
  • the signal strength detection unit 54 (SB3 and SB6) for detecting the signal strength of the received signal is provided, and the PAA weight control unit 44 performs the above-described processing according to the signal strength detected by the signal strength detection unit 54. Since the setting of the phase control unit 22 is changed, a suitable beam can be formed in a practical manner according to the signal strength of the received signal.
  • the antenna element 30 is arranged so that the distances between the adjacent antenna elements 30 are equal to each other, and the phase control unit 22 is symmetric with respect to a straight line indicating the communication direction.
  • the same phase control in transmission and Z or reception is performed so that the phase shift amount is doubled as it is separated from the straight line indicating the communication direction for each pair of antenna elements 30 arranged at the positions Therefore, the phase control can be made as simple as possible.
  • the tag distance detection unit 60 detects a relative distance from the wireless tag 14 based on a received signal corresponding to the setting of the phase control unit 22, The distance can be easily detected.
  • a signal strength detection unit 54 for detecting the signal strength of the received signal is provided, and the tag distance detection unit 60 is based on the signal strength detected by the signal strength detection unit 54. Since the relative distance to the line tag 14 is detected, the relative distance to the wireless tag 14 can be easily detected in a practical manner.
  • the tag distance detection unit 60 has a relative distance from the wireless tag 14 based on the setting of the phase control unit 22 that maximizes or minimizes the signal intensity detected by the signal intensity detection unit 54. Therefore, the relative distance to the communication target can be easily detected in a practical manner.
  • a BER detection unit 58 (SC3 and SC6) for detecting the bit error rate of the received signal is provided, and the tag distance detection unit 60 is based on the bit error rate detected by the BER detection unit 58. Since the relative distance from the wireless tag 14 is detected, the relative distance from the wireless tag 14 can be easily detected in a practical manner.
  • the tag distance detection unit is configured to have a relative distance from the wireless tag 14 based on the setting of the phase control unit 22 that maximizes or minimizes the bit error rate detected by the BER detection unit 58. Therefore, the relative distance from the wireless tag 14 can be easily detected in a practical manner.
  • a tag distance detection unit 60 that detects a relative distance to the wireless tag 14 is provided, and the relative distance to the wireless tag 14 detected by the tag distance detection unit 60 is the dimension of the array antenna 16. Phase control through the phase control unit 22 when the phase control is less than three times the phase control unit 22, so that phase control is required when phase control through the phase control unit 22 is required. It can be performed.
  • the wireless communication device transmits a predetermined transmission signal toward the wireless tag 14 that is a communication target, and receives a reply signal returned from the wireless tag 14 in response to the transmission signal.
  • This provides a wireless tag communication device 12 that improves communication characteristics when the distance to the wireless tag 14 is relatively short because the wireless tag communication device 12 communicates information with the wireless tag 14. can do.
  • FIG. 15 shows a wireless tag communication device which is another preferred embodiment of the wireless communication device of the first invention. 8 is a diagram for explaining the configuration of the device 88.
  • the RFID tag communication device 88 of the present embodiment controls the phase of the transmission signal supplied from the transmission signal modulation unit 20 and supplies it to the antenna elements 30b and 30c. 32b and the combined signal supplied from the multiplexer 25b, that is, the phase controller 9 having a reception phase shifter 34b that controls the phase of the received signal corresponding to the antenna elements 30b and 30c and supplies the signal to the down converter 28b.
  • the phase control unit 90 includes neither the transmission phase shift unit 32a nor the reception phase shift unit 34a in the phase control unit 22 described above.
  • the phase control unit 90 is arranged at a position farthest from the straight line cable indicating the communication direction among the pair of antenna elements 30 disposed at positions symmetrical with respect to the straight line indicating the communication direction.
  • Corresponding to the paired antenna elements 30a and 30d is not provided with a phase shift section, and the same phase control in transmission and Z or reception is performed corresponding to the other antenna elements 30b and 30c.
  • a single transmission phase shifter 32b and a reception phase shifter 34b are provided. If the communication direction of the array antenna 16, that is, the direction in which the wireless tag 14 to be communicated is arranged as shown in FIG. 6 described above, it is simply symmetrical with respect to a straight line indicating the communication direction.
  • the pair of antenna elements 30 disposed at the position the pair of antenna elements 30a and 30d other than the pair of antenna elements 30a and 30d disposed farthest from the straight line indicating the communication direction 30
  • the communication characteristics can be improved by eliminating the phase difference.
  • the number of phase shift portions can be further reduced as compared with the configuration shown in FIG. 2 described above.
  • the phase control unit 90 includes a straight line curve indicating the communication direction of the pair of antenna elements 30 arranged at positions symmetrical with respect to the straight line indicating the communication direction.
  • a single transmission shift for performing the same phase control in transmission corresponding to the paired antenna elements 30b and 30c other than the paired antenna elements 30a and 30d disposed at the most distant positions Since the phase unit 32b and the single reception phase shift unit 34b for performing the same phase control in reception are provided, the same phase control is performed in a practical manner for each pair of antenna elements 30.
  • the configuration can be made as much as possible by not providing a phase shift portion corresponding to the pair of antenna elements 30a and 30d disposed at the position farthest from the straight line indicating the communication direction. It can be simple.
  • the preferred embodiments of the first invention have been described above in detail with reference to the drawings. However, the first invention is not limited to these embodiments, and may be implemented in other modes.
  • the array antenna 16 is composed of a plurality of rod-shaped antenna elements 30 disposed so as to be parallel to each other in the same plane.
  • a plurality of planar antenna elements 92a, 92b, 92c, 92d, and 92e (hereinafter not particularly distinguished, in some cases, as shown in FIG. 16).
  • the first invention may be applied to a two-dimensional array antenna 90 having a force (referred to as a planar antenna element 92).
  • the communication direction of the two-dimensional array antenna 90 is, for example, the center of the planar antenna element 92 that is perpendicular to the plane on which the plurality of planar antenna elements 92 are disposed as shown by arrows in FIG.
  • planar antenna elements 92a and 92c, 92d and 92e are respectively arranged at positions symmetrical with respect to the straight line. Further, a phase shift portion 94a is provided corresponding to the planar antenna elements 92a and 92c, and a phase shift portion 94b is provided corresponding to the planar antenna element 92b. According to such a configuration, in the wireless communication apparatus including the two-dimensional array antenna 90 composed of the planar antenna elements 92 such as patch antennas, the same pair of planar antenna elements 92 are practically the same. Phase control can be performed.
  • the array antenna 16 has an even number of antenna elements 30, but the first invention is suitably applied to an array antenna having an odd number of antenna elements 30. Is done.
  • the phase control unit 22 and the like are symmetrical with respect to a straight line indicating the communication direction other than one antenna element 30 arranged on the straight line indicating the communication direction among the antenna elements 30.
  • the same phase control in transmission and Z or reception is performed for each pair of antenna elements 30 arranged at the positions. In this way, in a wireless communication apparatus including an array antenna composed of an odd number of antenna elements 30, the same phase control can be performed in a practical manner for each pair of antenna elements 30.
  • the plurality of antenna elements 30 are arranged so as to be parallel to each other in the same plane. These antenna elements 30 are not necessarily the same. If it is an array antenna having a pair of antenna elements arranged at positions symmetrical with respect to the straight line indicating the communication direction, not necessarily arranged in one plane, the effect of the first invention can be obtained. Play.
  • the bit error rate detection unit detects the bit error rate of the received signal.
  • the bit error rate detection unit may detect the frame error rate (FER) of the received frame. Good.
  • FER frame error rate
  • the frame error rate can be detected suitably.
  • FIG. 17 is a diagram for explaining the configuration of a wireless tag communication device 112 as an embodiment of the wireless communication device of the second invention.
  • the wireless tag communication device 112 shown in FIG. 17 is preferably used in the wireless tag communication system 10 in FIG. 1 and the like that communicates with the wireless tag 14 described above, and generates a main carrier wave of a transmission signal.
  • the main carrier wave generator 118 and the main carrier wave generated by the main carrier wave generator 118 are modulated by a transmission information signal (transmission data) generated by a transmission data generator 142, which will be described later, and the transmission signal is modulated.
  • a plurality of antenna elements 130a, 130b, 130c, and 130d (hereinafter simply referred to as antenna element 130 unless otherwise specified) and a plurality of antennas for both transmission and reception for receiving
  • a directivity control unit 122 for controlling the transmission directivity of the transmission signal transmitted from the slave 130 and controlling the reception directivity of the reception signal received by the plurality of antenna elements 130, and the directivity control thereof.
  • transmission / reception demultiplexing units that supply transmission signals supplied from the unit 122 to the antenna elements 130 and also receive reception signals received by the antenna elements 130 to the directivity control unit 122.
  • 124a, 124b, 124c, 124d (hereinafter simply referred to as a transmission / reception separation unit 124 unless otherwise distinguished), a local oscillator 126 that generates a local signal of a predetermined frequency, and the directivity control unit 122.
  • Local oscillation for each received signal Multiple down-converters (4 in Fig.
  • the plurality of antenna elements 130 constitute an array antenna 116.
  • a circulator, a directional coupler, or the like is preferably used as the transmission / reception separating unit 124.
  • the directivity control unit 122 controls a plurality of (four in FIG. 17) transmission phase shifters 132a, 132b, and 132c that control the phase of each transmission signal supplied from the transmission signal modulation unit 120. , 132d (hereinafter simply referred to as “transmission phase shifter 132” unless otherwise specified) and a plurality (four in FIG. 17) of transmission amplifiers 134a, 134b, 134c, 134d (hereinafter referred to as “transmission phase shifter 132”). Unless otherwise distinguished, simply referred to as a transmission amplifying unit 134), and a transmission signal transmitted from the plurality of antenna elements 130 via the transmission phase shifting unit 132 and the transmission amplifying unit 134.
  • the transmission directivity of the transmission signal is controlled by controlling the phase, Z, or amplitude of each signal.
  • a plurality (four in FIG. 17) of receiving phase shifters 136a, 136b, 136c, 136d that control the phase of each of the received signals supplied from the plurality of transmission / reception separators 124 (hereinafter, unless otherwise specified) Is simply referred to as a reception phase shift unit 136) and a plurality (four in FIG. 17) of reception amplification units 138a, 138b, 138c, and 138d for controlling the respective amplitudes (hereinafter simply referred to as reception amplification unless otherwise specified).
  • reception amplification for controlling the respective amplitudes
  • the control unit 140 includes a CPU, a ROM, a RAM, and the like, and is a so-called microcomputer that performs signal processing according to a program stored in advance in the ROM while using a temporary storage function of the RAM.
  • Generation of transmission data determination of control amounts of the transmission phase shift unit 132 and transmission amplification unit 134, determination of control amounts of the reception phase shift unit 136 and reception amplification unit 138, transmission signal toward the wireless tag 14
  • Transmission control for transmitting data, reception control for receiving a reply signal returned from the wireless tag 14 in response to the transmission signal, and And demodulation control for demodulating the received signal.
  • a transmission data generation unit 142 In order to execute such control, a transmission data generation unit 142, a PAA weight control unit 144, a reception signal synthesis unit 150, a reception signal demodulation unit 152, a signal strength detection unit 154, and a tag position estimation unit 156 are functionally provided. ing.
  • the transmission data generation unit 142 generates transmission data to be transmitted to the radio tag 14 on the carrier wave generated by the main carrier generation unit 118, and transmits the transmission data to the transmission signal modulation unit 120. Supply.
  • modulation is performed based on the transmission data supplied from the transmission data generation unit 142 to obtain a transmission signal, which is transmitted from the antenna element 130 via the directivity control unit 122 and the like. Is done.
  • the PAA weight control unit 144 includes a transmission control unit 146 and a reception control unit 148, and each phase (and amplitude if necessary) of the transmission signals transmitted from the plurality of antenna elements 130.
  • the transmission directivity is controlled by controlling.
  • the reception directivity is controlled by controlling the phase (and amplitude if necessary) of each reception signal received by the plurality of antenna elements 130.
  • each antenna element 130 functions as a phase control unit that controls the phase related to transmission and Z or reception.
  • the transmission control unit 146 controls the phase of each transmission signal via the directivity control unit 122, thereby transmitting a transmission antenna including the plurality of antenna elements 130 to a phased array antenna for transmission (Phased Array antenna). Control as Antenna).
  • the reception control unit 148 controls the reception directivity of the reception signal by controlling the phase (and amplitude if necessary) of each reception signal received by the plurality of antenna elements 130. That is, by controlling the phase of each reception signal via the directivity control unit 122, the reception antenna composed of the plurality of antenna elements 130 is controlled as a reception phased array antenna.
  • the reception signal combining section 150 combines (adds) the reception signals respectively received by the plurality of antenna elements 130. Further, the reception signals respectively received by at least two antenna elements 130 selected from the plurality of antenna elements 130 are synthesized. That is, in the RFID tag communication apparatus 112 of the present embodiment, the reception is received by each of the at least two antenna elements 130 selected from the plurality of antenna elements 130.
  • the phase of the signal is controlled by the directivity control unit 122, the received signals are combined by the received signal combining unit 150, and the signal strength of the combined signal can be detected by the signal strength detecting unit 154. ing.
  • the received signal demodulator 152 demodulates the received signals from the plurality of antenna elements 130 synthesized by the received signal synthesizer 150. Preferably, after the received signal is AM demodulated by the AM method, the demodulated signal is FM-decoded to read an information signal related to the modulation by the wireless tag 14.
  • the signal strength detection unit 154 detects the signal strength of the received signal received by at least one antenna element 130 out of the plurality of antenna elements 130. Further, the signal strength of the synthesized signal synthesized by the received signal synthesis unit 150 is detected. That is, the signal strength of the combined signal of the received signals received by at least two antenna elements 130 selected from among the plurality of antenna elements 130 is detected.
  • the tag position estimation unit 156 estimates a relative position of the wireless tag 14 that is a communication target with respect to the wireless tag communication device 112 or the array antenna 116. This estimation is preferably performed based on the detection result by the signal intensity detection unit 154.
  • the tag position estimation unit 156 estimates the relative position of the wireless tag 14, and the PAA weight control unit 144 controls the phase related to transmission and Z or reception in each antenna element 130 according to the estimation result. Detailed description.
  • FIG. 18 is a diagram for explaining the relative positional relationship between the array antenna 116 provided in the wireless tag communication device 112 of the present embodiment and the wireless tag 14 that is the communication target.
  • the array antenna 116 is preferably provided in a fixed position with respect to the wireless tag communication device 112, and the relative positional relationship of the wireless tag 14 with respect to the wireless tag communication device 112 is the array. This can be considered as a relative positional relationship between the antenna 116 and the wireless tag 14.
  • Such relative positional relationship is determined by (1) the plane coordinates defined by the first linear coordinates and the second linear coordinates orthogonal to the first linear coordinates, and (2) the relative distance and the relative direction. Expressed in polar coordinates.
  • the origin is at the center of the arrangement width direction of the plurality of antenna elements 130 (the midpoint between the antenna elements 130b and 130c).
  • the xy coordinate plane coordinate
  • the xy coordinate plane coordinate
  • the relative positional relationship of the wireless tag 14 with respect to the array antenna 116 is expressed with respect to the xy coordinates.
  • the relative distance from the center in the arrangement width direction of the plurality of antenna elements 130 (the position indicated by the origin of the xy coordinates in FIG. 18), a straight line passing through the center and perpendicular to the plane (in FIG. 18).
  • the relative angle relative to the straight line indicated by the y-axis) is defined as 0, and the relative position relationship of the wireless tag 14 with respect to the array antenna 116 with respect to the r- ⁇ coordinate (polar coordinate) determined by the relative distance r and relative direction ⁇
  • the relative positional relationship of the RFID tag 14 with respect to the array antenna 1 16 and hence the RFID tag communication device 112
  • the xy coordinates and! Consider the relative positional relationship with respect to the 0 coordinate.
  • FIG. 19 shows the relative position of the wireless tag 14 with respect to the X coordinate that is the first linear coordinate and the y coordinate that is the second linear coordinate orthogonal to the first linear coordinate and the transmission at each antenna element 130.
  • an xy coordinate table 78 as a first table showing a correspondence relationship with Z or a phase related to reception
  • FIG. 20 shows a relative distance r to the wireless tag 14 and a relative direction ⁇ of the wireless tag 14 and each antenna.
  • FIG. 10 is an r-0 coordinate table 180 as a second table showing a correspondence relationship between transmission and Z or reception phase in the element 130.
  • both the xy coordinate table 178 and the r- ⁇ coordinate table 180 provided in the RFID tag communication apparatus 112 of the present embodiment have a short relative distance to the RFID tag 14. The stubbornness is defined as a response.
  • the relative distance is ⁇ / 10 intervals. If!: Is greater than or equal to ⁇ and less than 5 ⁇ , the relative distance!: Is 5 at intervals of ⁇ ⁇ 4 If it is equal to or larger than ⁇ , the correspondence between the relative position of the wireless tag 14 and the phase related to transmission and reception or reception at each antenna element 130 is determined at the same interval as that of a normal plane wave. As the relative distance r becomes closer, the relative position of the wireless tag 14 can be estimated or detected in more detail! /.
  • a plurality of modes are used for phase control using a table showing the correspondence between the relative position of the wireless tag 14 and the phase related to transmission and Z or reception in each antenna element 130.
  • the tag position estimation unit 156 estimates the relative position of the wireless tag 14 using the xy coordinate table 178 and the Z or r-0 coordinate table 180, and based on the result, each antenna is estimated.
  • a mode for determining the phase in the element 130 is conceivable.
  • the tag position estimation unit 156 stores the xy coordinate table 178 and the Z or r- ⁇ coordinate table 180 in the phase control related to transmission and Z or reception in each antenna element 130 by the PAA weight control unit 144.
  • the PAA weight control unit 144 controls the phase related to transmission and Z or reception in each antenna element 130 based on the relative position estimated by the tag position estimation unit 156. That is, the phase determined in the xy coordinate table 178 corresponding to the xy coordinates representing the relative position of the radio tag 14 estimated by the tag position estimation unit 156, or estimated by the tag position estimation unit 156 The phase determined in the r- ⁇ coordinate table 180 corresponding to the r- ⁇ coordinate indicating the relative position of the wireless tag 14 is applied to each antenna element 130.
  • the tag position estimation unit 156 estimates the relative distance r of the wireless tag 14, and based on the result, the xy coordinate table 178 and the Z or r-0 coordinate table A mode in which the phase in each antenna element 130 is determined using 180 is conceivable.
  • the tag position estimation unit 156 is configured such that any one of the plurality of antenna elements 130 provided in the array antenna 116 is one of the antenna elements 130 (preferably, the antenna element located at the center in the arrangement width direction).
  • the PAA weight control unit 144 corresponds to the relative distance r estimated by the tag position estimation unit 156 and all the correspondences defined in the xy coordinate table 178 and the Z or r- ⁇ coordinate table 180.
  • the relationship is applied as a whole, and the correspondence relationship in which the detection result by the signal intensity detection unit 154 takes the maximum value is applied to the phase control related to transmission and Z or reception in each antenna element 130.
  • r which is the estimation result
  • the relationship defined in correspondence with X -y that satisfies this mathematical formula is scanned.
  • the application range of the correspondence relationship defined in the xy coordinate table 178 and / or the r- ⁇ coordinate table 180 is limited, so that the phase control is performed more quickly than in the first mode. It can be carried out.
  • the tag position estimation unit 156 estimates the relative direction ⁇ of the wireless tag 14 and uses the xy coordinate table 178 and the Z or r- ⁇ coordinate table 180 based on the result. A mode of determining the phase in the antenna element 130 can be considered.
  • the tag position estimation unit 156 detects the detection result by the signal strength detection unit 154 regarding the received signals sequentially received by at least two antenna elements 130 of the plurality of antenna elements 130 provided in the array antenna 116. From the above, the relative direction ⁇ of the radio tag 14 is estimated.
  • the PAA weight controller 144 determines all the correspondences defined in the xy coordinate table 178 and the Z or r- ⁇ coordinate table 180 corresponding to the relative direction ⁇ estimated by the tag position estimator 156.
  • the correspondence relationship in which the detection result by the signal intensity detection unit 154 has the maximum value is applied to the phase control related to transmission and Z or reception in each antenna element 130.
  • the applicable range of the correspondence relationship defined in the xy coordinate table 178 and the Z or r-0 coordinate table 180 is limited, so that phase control is performed more quickly than in the first aspect. It can be carried out.
  • the signal intensity detection unit for the received signals sequentially received by at least two antenna elements 130 is obtained by combining the second aspect and the third aspect.
  • the detection result force of 54 is also used to estimate the relative distance r and the relative direction ⁇ of the wireless tag 14 by the tag position estimation unit 156, and the tag position estimation unit 156 from the xy coordinate table 178 and the Z or r- ⁇ coordinate table 180.
  • the phase related to transmission and Z or reception in each antenna element 130 may be controlled based on the relative distance r and the relative direction ⁇ estimated by.
  • the tag position estimation unit 156 estimates the relative distance r of the wireless tag 14, and according to the result, the xy coordinate table 178 and the r- ⁇ coordinate table 180 are used. A mode in which the phase in each antenna element 130 is determined by selective use can be considered.
  • the tag position estimation unit 156 estimates the relative distance r of the wireless tag 14 based on the detection result by the signal intensity detection unit 154. Then, when the estimation result by the tag position estimation unit 156, that is, the estimated relative distance r is less than a predetermined value, the PAA weight control unit 144 shows the first table in the xy coordinate table 178.
  • the corresponding relationship power also controls the phase related to transmission and Z or reception in each antenna element 130, and when the relative distance r estimated by the tag position estimation unit 156 is greater than or equal to a predetermined value,
  • the corresponding force shown in the r- ⁇ coordinate table 180 also controls the phase of transmission and Z or reception at each antenna element 130.
  • phase control is performed with high accuracy in other cases, and simple phase control with necessary and sufficient accuracy is performed in other cases. By doing so, it is possible to improve both the communication characteristics and shorten the communication time.
  • FIG. 21 is a flowchart for explaining an example of reception phase control by the control unit 140 of the RFID tag communication apparatus 112, which is repeatedly executed at a predetermined cycle.
  • step (hereinafter, step is omitted) S1 the one antenna element 130b or 130c located in the center of the arrangement width direction among the plurality of antenna elements 130 provided in the array antenna 116 is used as described above.
  • a signal from the wireless tag 14 is received.
  • S2 corresponding to the operation of the tag position estimation unit 156
  • the signal strength of the received signal received in S1 is detected, and the detection result power is also determined by the relative distance r of the wireless tag 14. Presumed.
  • S3 depending on the estimation result estimated in S2,
  • the scanning range in the xy coordinate table 178 and the Z or r- ⁇ coordinate table 180 is determined.
  • S4 it is determined whether or not n indicating the scanning position in the xy coordinate table 178 and / or the r- ⁇ coordinate table 180 has reached the terminal value N.
  • the scanning position n is selected from the corresponding relationships defined in the xy coordinate table 178 and / or the r- ⁇ coordinate table 180 by the PAA weight control unit 144. After being applied to phase control related to transmission and Z or reception in each antenna element 130 so that the phase value of the table position shown in FIG.
  • the received signal received by the antenna element 130 is combined, and the signal strength R of the combined signal is detected.
  • S5a it is determined whether or not the signal strength R is greater than the maximum signal strength R.
  • S6 and subsequent steps are executed immediately.
  • S6, 1 is added to n, and then the process from S4 is executed again.
  • the PAA weight control unit 144 sets the transmission and / or reception phase shifter values in S7 in the xy coordinate table 178 and the Z or r- ⁇ coordinate table 180. After the phase value at the table position M where the signal strength of the combined signal has the maximum value is applied to the phase control related to transmission and Z or reception at each antenna element 130, the routine is terminated.
  • S2 and S5 correspond to the operation of the signal intensity detection unit 154.
  • FIG. 22 is a flowchart for explaining another example of the reception phase control by the control unit 140 of the RFID tag communication apparatus 112, which is repeatedly executed at a predetermined cycle.
  • steps that are common to each other are denoted by the same reference numerals and description thereof is omitted.
  • FIG. 23 is a flowchart for explaining yet another example of reception phase control by the control unit 140 of the RFID tag communication apparatus 112, which is repeatedly executed at a predetermined cycle.
  • the angle ⁇ corresponding to the reception directivity of the array antenna 116 is set to ⁇ 60 °.
  • S12 corresponding to the operation of the signal strength detection unit 154
  • signals from the wireless tag 14 are received by two antenna elements 130 among the plurality of antenna elements 130 provided in the array antenna 116.
  • the combined signal strength of the received signal is detected.
  • 10 ° is added to the angle ⁇ .
  • S14 it is determined whether or not the angle ⁇ force is greater than 1 ⁇ 20 °. If the determination of S14 is negative, the force to execute the processing subsequent to S12 again. If the determination of S14 is positive, in S15 corresponding to the operation of the tag position estimation unit 156, the combination is performed.
  • FIG. 24 is a flowchart for explaining yet another example of reception phase control by the control unit 140 of the RFID tag communication apparatus 112, which is repeatedly executed at a predetermined cycle.
  • a signal from the wireless tag 14 is received by the A antenna element, that is, the antenna element 130a, and the signal strength of the received signal is detected.
  • the relative distance ra of the wireless tag 14 to the antenna element 130a is estimated based on the signal intensity detected in S18.
  • the signal from the wireless tag 14 is received by the B antenna element, that is, the antenna element 130d, and the signal strength of the received signal is detected.
  • the relative distance rb of the wireless tag 14 with respect to the antenna element 130d is estimated based on the signal strength detected in S20.
  • S22 based on the distance ra detected in S19 and the distance rb detected in S21, intersections of straight lines indicating the distances ra and rb are calculated.
  • S23 the corresponding relationship force determined in the xy coordinate table 178 or the r-0 coordinate table 180 is also determined as the intersection point calculated in S22, and the phase corresponding to the relationship is determined. Is done.
  • S24 corresponding to the operation of the PAA weight control unit 144, after the phase determined in S16 is applied to the plurality of antenna elements 130, this routine is terminated.
  • S19 and S21 correspond to the operation of the signal strength detection unit 154
  • S19, S21, S22, and S23 correspond to the operation of the tag position estimation unit 156, respectively.
  • the tag position estimation unit 156 (S2, S15, S19, S21, as a communication target position estimation unit that estimates the relative position of the wireless tag 14 that is a communication target. S 22 and S 23), and a PA A weight control unit 144 (S7, S17) as a phase control unit for controlling the phase related to transmission and Z or reception in each antenna element 130 according to the estimation result by the tag position estimation unit 156 , And S24), and by controlling the phase corresponding to each antenna element 130 in accordance with the relative distance r and Z or the relative direction ⁇ of the wireless tag 14, the wireless tag Even when the relative distance r with respect to 14 is relatively close, phase synthesis can be suitably performed and communication accuracy can be improved. That is, it is possible to provide the wireless tag communication device 112 that improves the communication characteristics when the relative distance to the wireless tag 14 is relatively short.
  • the phase corresponding to each antenna element 130 can be suitably controlled by simple control compared to the well-known AA A (Adapted Array Antenna) processing. There is an advantage that the time required for communication can be shortened.
  • the tag position estimation unit 154 (Sl, S5, S12, S19, and S21) that detects the signal strength of the reception signal received by the at least one antenna element 130 is provided.
  • the unit 156 estimates the relative position of the radio tag 14 based on the detection result by the signal intensity detection unit 154, and therefore can estimate the relative position of the radio tag 14 in a practical manner. .
  • Tables 178 and 180 indicating the correspondence between the relative position of the wireless tag 14 and the phases related to transmission and Z or reception in each antenna element 130 are provided.
  • the PAA weight control unit 144 includes the table 178. 180, the phase relating to transmission and Z or reception in each antenna element 130 is controlled based on the estimation result by the tag position estimation unit 156 from the correspondence relationship shown in 180, so that each antenna element 130 is practically used.
  • the phase corresponding to can be set to a suitable value.
  • the xy coordinate table 178 includes a relative position of the wireless tag 14 with respect to an x coordinate that is a first linear coordinate and a y coordinate that is a second linear coordinate orthogonal to the first linear coordinate. Since this shows the correspondence relationship between the phase related to transmission and Z or reception in each antenna element 130, the phase corresponding to each antenna element 130 can be set to a suitable value in a relatively highly accurate and practical manner. .
  • the r- ⁇ coordinate table 180 indicates the relative distance r to the wireless tag 14 and the relative direction ⁇ of the wireless tag 14 and the phase related to transmission and Z or reception in each antenna element 130. Since the correspondence relationship is shown, the phase corresponding to each antenna element 130 can be set to a suitable value in a simple and practical manner.
  • the tag position estimation unit 156 applies the correspondence relationships shown in the tables 178 and 180 in the phase control related to transmission and Z or reception in each antenna element 130, and the signal strength detection unit 154 Corresponding force having the maximum detection result
  • the relative distance r and the relative direction ⁇ of the wireless tag 14 are estimated, and the PAA weight controller 144 determines the relative distance estimated by the tag position estimator 156. Because the phase for transmission and Z or reception at each antenna element 130 is controlled based on the distance !: and the relative direction ⁇ , the phase corresponding to each antenna element 130 is relatively accurately and practically used. A suitable value can be obtained.
  • the tag position estimation unit 156 estimates the relative distance r of the wireless tag 14 based on the detection result force of the signal strength detection unit 154 related to the received signal received by one antenna element 130,
  • the PAA weight control unit 144 applies the correspondence relationships shown in the tables 178 and 180 corresponding to the relative distance r estimated by the tag position estimation unit 156, and the detection result by the signal intensity detection unit 154 is applied. Since the correspondence that takes the maximum value is applied to phase control related to transmission and Z or reception in each antenna element 130, the phase corresponding to each antenna element 130 is set to an appropriate value in a simple and practical manner. be able to.
  • the tag position estimation unit 156 estimates the relative distance r and the relative direction ⁇ of the wireless tag 14 from the detection result by the signal strength detection unit 154 regarding the received signals sequentially received by the two antenna elements 130.
  • the PAA weight control unit 144 performs transmission and Z or reception in each antenna element 130 based on the relative distance r and the relative direction ⁇ estimated from the tables 178 and 180 by the tag position estimation unit 156. Therefore, the phase corresponding to each antenna element 130 can be set to a suitable value in a simple and practical manner.
  • the xy coordinate table 178 as the first table indicating the correspondence relationship with Z or the phase related to reception
  • the relative distance r between the wireless tag 14 and the relative direction ⁇ of the wireless tag 14 and the transmission and transmission at each antenna element 130 R- ⁇ coordinate table 180 as a second table showing the correspondence relationship with Z or phase related to reception
  • the tag position estimation unit 156 is based on the detection result by the signal intensity detection unit 154!
  • the PAA weight control unit 144 estimates the relative distance r of the wireless tag 14, and the XY coordinate table 144 is obtained when the estimation result by the tag position estimation unit 156 is less than a predetermined value. Shown in 178 The corresponding relational power also controls the phase related to transmission and Z or reception in each antenna element 130, and when the estimation result by the tag position estimation unit 156 is a predetermined value or more, it is shown in the r- ⁇ coordinate table 180. Because it controls the phase related to transmission and Z or reception in each antenna element 130. When the wireless tag 14 is placed at a very short distance, phase control is performed with high accuracy in other cases, and in other cases, simple phase control is performed with necessary and sufficient accuracy. Both improvement and reduction of communication time can be realized.
  • the wireless communication apparatus transmits a predetermined transmission signal toward the wireless tag 14 that is a communication target, and is returned from the wireless tag 14 in response to the transmission signal. Since the wireless tag communication device 112 performs communication of information with the wireless tag 14 by receiving a signal, the wireless tag communication improves communication characteristics when the distance from the wireless tag 14 is relatively close. A device 14 can be provided.
  • the PAA weight control unit 144, the signal intensity detection unit 154, the tag position estimation unit 156, and the like are all functionally provided in the control unit 140.
  • the second invention is not limited to this.
  • a control device having a function corresponding to each of the PAA weight control unit 144, the signal strength detection unit 154, and the tag position estimation unit 156 is provided individually. It may be a In addition, the control by these control devices may be digital signal processing or analog signal processing.
  • the directivity control unit 122 is arranged close to and at a position so as to perform the high-frequency signal, but the directivity control is not a high-frequency signal but a baseband or This may be done at an intermediate frequency (IF).
  • the directivity control need not be performed on the analog signal, but may be realized by digital processing in the control unit 140.
  • the second invention is mainly applied to the reception control among the transmission control and the reception control in the communication with the wireless tag 14
  • the second invention is also suitably used for phase control of each transmission signal transmitted from the plurality of antenna elements 130 in communication with the wireless tag 14.
  • a wireless tag capable of detecting the signal strength of the transmission signal from the wireless tag communication device 112 is used, and data indicating the signal strength of the transmission signal detected on the wireless tag side is a response. Is returned to the wireless tag communication device 112 as a wave, and the wireless tag communication device 112 estimates the relative position of the wireless tag that is the object of communication based on the data indicating the transmission signal intensity included in the response wave.
  • the transmission directivity direction of the array antenna 116 as a transmission antenna is shaken, and the relative presence of the wireless tag 14 from the direction in which the response from the wireless tag 14 is obtained.
  • a mode is also conceivable in which the direction is estimated and the phase related to transmission in each antenna element 130 is controlled in accordance with the estimation result.
  • a predetermined transmission signal is transmitted toward the wireless tag 14 that is a communication target, and a reply signal returned from the wireless tag 14 in response to the transmission signal is received.
  • the second invention is applied to the RFID tag communication device 112 that communicates information with the RFID tag 14.
  • other examples such as a mobile phone and a mobile communication device have been described.
  • the second invention can be preferably applied to a wireless communication device.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Variable-Direction Aerials And Aerial Arrays (AREA)
  • Radio Transmission System (AREA)

Abstract

La présente invention a pour but de fournir un dispositif de communication sans fil en mesure de présenter une caractéristique de communication améliorée lorsque la distance relative depuis l'autre extrémité de communication est relativement courte. Une partie de réglage de phase (22) est fournie pour effectuer le même réglage de phase lors de la transmission et/ou réception pour chacun des éléments d'antenne appariés (30) disposés à des positions symétriques par rapport à une ligne droite indiquant une direction de communication. En raison de la fourniture de cette partie de réglage de phase, dans la mesure où les déphasages par rapport à la position centrale pour les éléments d'antenne appariés (30) disposés à des positions symétriques par rapport à la ligne droite indiquant la direction de communication sont égaux, le même réglage de phase est effectué pour chacun des éléments d'antenne appariés (30), ce qui fait que, même lorsque la distance relative depuis un repère sans fil (14) qui est l'autre extrémité de communication change, un faisceau peut être formé en fonction de cette distance. C'est-à-dire qu'il est possible de fournir un dispositif de communication à repère sans fil (12) en mesure de présenter une caractéristique de communication améliorée lorsque la distance relative depuis l'autre extrémité de communication est relativement courte.
PCT/JP2007/063118 2006-08-11 2007-06-29 Dispositif de communication sans fil WO2008018254A1 (fr)

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JP2006-220701 2006-08-11
JP2006-220700 2006-08-11
JP2006220700A JP2008048077A (ja) 2006-08-11 2006-08-11 無線通信装置
JP2006220701A JP4816320B2 (ja) 2006-08-11 2006-08-11 無線通信装置

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