JP2006086677A - Radio receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio receiver in which high reception sensitivity can be attained in a relatively short time. <P>SOLUTION: The radio receiver comprises a plurality of antennas 2A-C for receiving transmission waves from a radio tag T by radio communication, a phased array control section 200 performing the first control of the antennas 2A-C for varying the direction thereof sequentially while sustaining the directivity thereof in a predetermined direction, and an adaptive array control section 250 performing the second control of the antennas 2A-C for varying the directivity thereof so that the receiving state for the radio tag T is optimized wherein a BB section 10 controls the directivity of the antennas 2A-C by switching these two controls selectively. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wireless reception device that receives a signal transmitted from an external communication target through wireless communication.

  For example, an RFID (Radio Frequency) that reads / writes information of a wireless tag by transmitting and receiving an inquiry and receiving a response from a reader / writer as an interrogator with respect to a small wireless tag as a responder Identification) system is known.

  For example, a wireless tag circuit element included in a label-like wireless tag includes an IC circuit unit that stores predetermined wireless tag information and an antenna that is connected to the IC circuit unit and transmits / receives information. The IC circuit unit demodulates and interprets the signal received by the antenna, reflects and modulates the received carrier wave based on the information signal stored in the memory, and returns it to the interrogator via the antenna.

  On the other hand, in general radio receiving apparatuses including the interrogator, a so-called adaptive control technique called AAA (Adaptive Array Antenna) processing has been known in order to perform demodulation processing in the above-described wireless communication with high sensitivity. (For example, refer to Patent Document 1). In this method, a plurality of antenna elements are provided as receiving antennas in the receiver, and weights (weight values) are added to the received signals transmitted from the communication target (transmitter) and received by the plurality of antenna elements. Demodulate the processed received signal. Then, by changing the weight so that the error between the demodulated signal and the reference signal is as small as possible, the directivity by multiple antenna elements is changed so that the reception sensitivity to the transmission side is optimized. It is something to be made.

  On the other hand, as described above, as another example of directivity control via a plurality of antenna elements, in order to accurately know the position of a communication target, the directivity by a plurality of antenna elements is held so as to be strong in only one direction. So-called phased array control is also known in which the position of the transmitter is searched by sequentially changing the direction.

JP 2002-280945 A (paragraph numbers 0002 to 0035, FIG. 3)

  However, the following problems exist in the above-described conventional technology.

  That is, in an actual radio wave environment, various radio wave obstructions and interferences are often present between the transmitter and the receiver. For example, a transmission wave from the transmitter is directly applied to the receiving antenna of the receiver. In addition to being received, a transmission wave from the transmitter may be reflected by these obstacles separately from the direct wave (desired wave) and the reflected wave may be received by the receiving antenna.

  In such a case, in the adaptive array control, there is a possibility that the directivity of a plurality of antenna elements is directed to both the direct wave and the reflected wave. The reception sensitivity for the direct wave from the transmitter is not sufficient. On the other hand, in the phased array control, when there is no large difference in amplitude when receiving the direct wave and the reflected wave, the direction of the reflected wave is mistaken as the direction of the transmitter, and the original transmitter The direction may not be determined quickly.

  In any case, in the prior art, it is actually difficult to obtain a desired high receiving sensitivity in a short time.

  An object of the present invention is to provide a wireless receiver capable of obtaining high reception sensitivity in a relatively short time.

  In order to achieve the above object, the first invention provides a plurality of antenna elements that receive a transmission wave from a communication target via wireless communication, and directivity of these antenna elements in a predetermined direction. And a second control for changing the directivity of the plurality of antenna elements so that the reception state with respect to the communication target is optimized. And second directivity control means for controlling directivity of the plurality of antenna elements by the first control means and the second control means.

  In the first invention of the present application, the directivity control means maintains the directivity of the plurality of antenna elements in a predetermined direction and sequentially changes the direction thereof, and the received signal is a reference signal. The directivity of the plurality of antenna elements is controlled based on second control means (adaptive array control) that changes the reception state with respect to the communication target to be optimal by approaching to. As a result, the reception direction determination performance by phased array control and the reception sensitivity improvement performance by adaptive array control can be cooperated, so the direction of the communication target is determined in a relatively short time and the reception sensitivity for that direction is increased. Can be improved.

  In a second aspect based on the first aspect, the directivity control means selectively controls the directivity of the plurality of antenna elements by selectively switching between the first control means and the second control means. It is characterized by.

  By selectively switching between the first control means and the second control means, the reception direction determination performance by phased array control and the reception sensitivity improvement performance by adaptive array control can be made to cooperate.

  According to a third invention, in the first or second invention, the directivity control means performs reception state optimization control in the second control means based on a directivity control result in the first control means. It is characterized by.

  As a result, the receiving state optimization control in the direction is performed by adaptive array control based on the direction determination of the communication target by phased array control, so that high reception sensitivity can be obtained in a relatively short time compared to the case of only adaptive array control. be able to.

  In a fourth aspect based on the third aspect, the directivity control means determines the weighting so that the synthesized output signal to be demodulated approaches the target signal according to the directivity control result in the first control means. There is provided weighting determining means, and combined output signal generating means for generating the combined output signal using the weighting determined by the weighting determining means.

  Based on the directivity control result by phased array control (= direction determination of communication target), the weighting determining unit determines the weighting, and the combined output signal generating unit generates the combined output signal using the weighting, whereby the phased array control is performed. It is possible to realize adaptive array control utilizing the result of As a result, high reception sensitivity can be obtained in a relatively short time.

  A fifth invention is characterized in that, in the fourth invention, the demodulating means for demodulating the synthesized output signal generated by the synthesized output signal generating means or a signal based on the synthesized output signal.

  By demodulating the adaptive array-controlled combined output signal or a signal based on this with the demodulation means, the received signal can be well demodulated by increasing the signal strength, and the information contained in the transmission wave can be accurately obtained. .

  In a sixth aspect based on the fifth aspect, the directivity control means determines whether or not signals received by the plurality of antenna elements are transmission waves from the communication target, according to a demodulation result of the demodulation means. The weighting determining means determines the weighting based on the determination result of the determining means.

  As a result, weighting is determined so that the reception sensitivity is large for the direction of the transmission wave from the communication target and the reception sensitivity is small for the direction other than the transmission wave direction, and the received signal strength for the transmission wave is quickly and reliably determined. Can be improved.

  In a seventh aspect based on the sixth aspect, the weight determination means increases the reception sensitivity in the direction determined as the transmission wave by the determination means, and determines in the direction determined as not the transmission wave. The weighting is determined so that the reception sensitivity becomes small.

  For the direction of the transmission wave from the communication target, determine the weighting so that the reception sensitivity is increased and the directivity is strong, and for the direction that is not the transmission wave direction, the reception sensitivity is reduced and the directivity is weakened. As a result, the received signal strength with respect to the transmission wave is improved quickly and reliably. As a result, a high received signal strength with respect to a transmission wave from the communication target can be obtained in a relatively short time.

  According to an eighth invention, in any one of the first to third inventions, the directivity control means includes a calculation means and a first control first control signal based on a phase control signal from the calculation means. A first weight determining means for determining a weight; a first combined output signal generating means for generating a first combined output signal for the first control using the first weight determined by the first weight determining means; The second weight determining means for determining the second weight for the second control based on the phase / amplitude control signal from the calculating means, and the second weight determined by the second weight determining means. And a second synthesized output signal generating means for generating a second synthesized output signal for the second control.

  Based on the phase control signal of the computing means, the first weight determining means determines the first weight, and the first combined output signal generating means generates the first combined output signal using the first weight, whereby the phased array control is performed. Can be realized. Similarly, the second weight determining means determines the second weight based on the phase / amplitude control signal of the calculating means, and the second combined output signal generating means generates the second combined output signal using the second weight. Adaptive array control can be realized.

  According to a ninth aspect, in the eighth aspect, the first combined output signal generating unit and the second combined output signal generating unit are shared by a single combined output signal generating unit, and the combined single combined output signal The generating means generates the first or second combined output signal for the first or second control using the weight determined by the first or second weight determining means.

  By using the combined output signal generating means in common in phased array control and adaptive array control, the configuration of the entire apparatus can be simplified and the cost can be reduced.

  In a tenth aspect based on the ninth aspect, the directivity control means selectively uses the weight determined by the first or second weight determination means to the one combined output signal generation means. Switching means for switching input is provided.

  By switching the signal input from the first or second weight determining means to the common combined output signal generating means by the switching means, when the weight from the first weight determining means based on the phase control signal is input, the composition for phased array control It can function as an output signal generation means, and can function as a composite output signal generation means for adaptive array control when a weight from the second weight determination means based on the phase / amplitude control signal is input.

  In an eleventh aspect based on the tenth aspect, the directivity control means divides a predetermined minute time unit into a first time segment and a second time segment, and the first weight determination is performed in the first time segment. The weight determined by the means is input to the common combined output signal generating means, and in the second time interval, the weight determined by the second weight determining means is used as the common combined output signal. A switching control unit that controls a switching operation of the switching unit so as to be input to the generation unit is provided.

  Thus, the switching control means controls the switching operation of the switching means, and the first synthesized output signal for the first control is generated by the common synthesized output signal generating means based on the weight from the first weight determining means in the first time interval. To generate phased array control while generating a second synthesized output signal for the second control by the common synthesized output signal generating means based on the weight from the second weight determining means in the second time interval. Adaptive array control can be realized.

  In a twelfth aspect based on the eleventh aspect, the switching control means can variably set the first time segment and the second time segment.

  Thereby, the ratio of the 1st time division and the 2nd time division which occupy for a predetermined minute time unit can be set variably, and time distribution with phased array control and adaptive array control can be determined freely.

  According to the present invention, the reception direction determination performance by phased array control and the reception sensitivity improvement performance by adaptive array control can be cooperated, so that the direction of the communication target is determined in a relatively short time and Reception sensitivity can be improved.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a system configuration diagram showing an overall outline of an RFID tag communication system to which this embodiment is applied.

  In FIG. 1, the RFID tag communication system S corresponds to an interrogator 100 (only one is shown, but there may be a plurality of interrogators) as a wireless reception device (wireless communication device) of the present embodiment. This is a so-called RFID (Radio Frequency Identification) communication system including a wireless tag T as a responder.

  The wireless tag T includes a wireless tag circuit element To including an antenna 151 and an IC circuit unit 150.

The interrogator 100 has a directivity within a predetermined plane and is configured to be variable in the direction in which transmission or reception can be performed with the maximum power. In this example, one transmitting antenna 1 and a plurality (three in this case, which may be four or more. The same applies hereinafter) receiving antennas (antenna elements) 2A, 2B, and 2C, and these antennas 1 and 2A are used. ˜2C provided to access (read or write) the IC circuit unit 150 of the RFID circuit element To and output a transmission signal (transmission wave Fc) as a digital signal, or the RFID circuit element BB (Base that executes digital signal processing such as demodulating the return signal (reflected wave Fr) from To
Band) unit 10, transmission signal D / A conversion unit 11 that converts the transmission signal output from BB unit 10 into an analog signal and outputs the analog signal, and the reception signals at reception antennas 2A to 2C are digital Receiving signal A / D converters 12a, 12b, and 12c (hereinafter simply referred to as a receiving signal A / D converter 12 unless otherwise specified), which are converted into signals and supplied to the BB unit 10. Yes.

  When a transmission wave Fc, which is a transmission signal, is transmitted from the interrogator 100, the transmission wave Fc is modulated based on a predetermined information signal in the RFID circuit element To of the RFID tag T that has received the transmission wave Fc. Information is transmitted and received by the interrogator 100 receiving and demodulating the reflected wave Fr.

  FIG. 2 is a block diagram illustrating an example of a functional configuration of the RFID circuit element To provided in the RFID tag T.

  In FIG. 2, the RFID circuit element To receives the transmission wave Fc and transmits the reflection wave Fr in a non-contact manner using the antennas 1, 2 </ b> A to 2 </ b> C on the interrogator 100 side and a high frequency such as a UHF band. The antenna 151 is configured to be connected to the antenna 151 and the IC circuit unit 150 is connected to the antenna 151 and performs digital signal processing.

  The IC circuit unit 150 includes a rectifying unit 152 that rectifies the carrier wave received by the antenna 151, a power source unit 153 that accumulates energy of the carrier wave rectified by the rectifying unit 152 and serves as a driving power source, and the antenna 151. A clock extraction unit 154 that extracts a clock signal from the received carrier wave and supplies the clock signal to the control unit 157; a memory unit 155 that functions as an information storage unit that can store a predetermined information signal; and a modem that is connected to the antenna 151 And a controller 157 for controlling the operation of the RFID circuit element To through the rectifier 152, the clock extractor 154, the modulator / demodulator 156 and the like based on the power from the power supply 153. ing.

  The modem 156 demodulates the communication signal received from the antenna 151 from the transmission antenna 1 of the interrogator 100 and reflects and modulates the carrier wave received from the antenna 1 based on the return signal from the controller 157. To do.

  The control unit 157 interprets the received signal demodulated by the modulation / demodulation unit 156, generates a return signal based on the information signal stored in the memory unit 155, and performs basic control such as returning by the modulation / demodulation unit 156. Execute proper control.

  The above description has been made by taking the RFID tag circuit element To of the type that does not use a subcarrier as an example. However, the present invention is not limited to this, and a subcarrier oscillation unit and a subcarrier modulation unit (both not shown) are provided. The subcarrier generated by the oscillating unit may be modulated by the subcarrier modulating unit based on a predetermined information signal input via the control unit 157 and returned from the antenna 151.

  FIG. 3 is a functional block diagram showing a functional configuration of the interrogator 100.

  In FIG. 3, the interrogator 100 includes the antennas 1, 2 </ b> A to 2 </ b> C, the BB unit 10, the transmission signal D / A conversion unit 11, and the reception signal A / D conversion unit 12, and a frequency at which a predetermined frequency conversion signal is output. The frequency of the transmission signal from the conversion signal output unit 13 and the BB unit 10 converted into an analog signal by the transmission signal D / A conversion unit 11 is the frequency of the frequency conversion signal output from the frequency conversion signal output unit 13. The frequency of the reception signal received by each of the up-converter 14 and the reception antennas 2A, 2B, and 2C that are increased and output to the transmission antenna 1 is lowered by the frequency of the frequency conversion signal output from the frequency conversion signal output unit 13. Down converters 15a, 15b, 15c that output to the received signal A / D converters 12a, 12b, 12c (hereinafter, unless otherwise distinguished) Simply and a called down-converter 15). A band pass filter may be further used.

  The BB unit 10 includes a CPU 20, a ROM (not shown), a RAM (not shown), 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. System.

  The BB unit 10 is output from the CPU 20, a transmission digital signal output unit 16 that outputs a transmission signal to the RFID circuit element To as a digital signal based on the control signal of the CPU, and an output from the transmission digital signal output unit 16. A modulation unit 17 that modulates the transmitted digital signal based on a predetermined information signal (transmission information) and supplies the modulated signal to the transmission signal D / A conversion unit 11, a fused array control unit 200 as a first control unit, The amplitude detector 220 that detects the amplitude of the received signal after processing by the phased array controller 200 and inputs the detection result to the CPU 20, the adaptive array controller 250 as the second control means, and the receiving antennas 2A, 2B, 2C Are demodulated and received by the adaptive array controller 250 and included in the received signal. And an AM demodulator 30 and an FM decoder 40 that read out and input to the CPU 20 a predetermined information signal (= modulated signal by the RFID circuit element To).

  The phased array control unit 200 inputs IF tables 201a, 201b, and 201c, which are basic IF wave tables for phase control that set directivity in an arbitrary direction, set by the CPU 20, and a phase control signal from the CPU 20, Correspondingly, phase shifters 202a, 202b, 202c for variably setting the phases of the received radio wave signals at the receiving antennas 2A, 2B, 2C while referring to the values of the IF tables 201a, 201b, 201c, and these transfer devices And an adder 203 that adds the outputs from 202A to 2C and outputs the sum to the amplitude detector 220.

  The adaptive array control unit 250 is a multiplication unit 251a, 251b, 251c to which the reception signal is supplied, and a weighting control unit (adaptive) that determines (controls) a weight (weight) to be given to the reception signal in the multiplication units 251a-c. A processing control unit) 252; an addition unit 253 that adds the signals from the multiplication units 251a to 251c and outputs the result to the AM demodulation unit 30; and a weighting control unit that generates a predetermined reference signal (target output signal) r And a reference signal generation unit 254 that outputs the data to 252.

  The weighting control unit 252 relates to the combined output signal added by the adding unit 253 so that the reception sensitivity of the antennas 2A to 2C is optimized with respect to the direction in which the RFID tag T is disposed (= the RFID circuit element) By controlling the directivity by changing the amplitude and phase of each of the received signals received by the antennas 2A to 2C (so as to make the amplitude of the modulation component due to To as high as possible and approach the reference signal r) The accuracy of demodulation processing by the demodulator 30 is increased as much as possible. Therefore, predetermined weighting is performed for each antenna 2A, 2B, 2C in the phase control signal from the weighting control unit 252 to the multiplication units 251a to 251c, and transmission / reception is performed while changing this weighting (weighting value; weight). Convergence calculation is performed repeatedly. The reception signals adaptively processed by the multipliers 251 a to 251 c by the control signal of the weighting controller 252 are added together by the adder 253 and then output to the AM demodulator 30.

  The AM demodulator 30 performs IQ quadrature demodulation, that is, converts the input signal from the BB unit 10 into an I phase (In phase) signal and a Q phase (Quadrature phase) signal whose phases are 90 ° different from each other, and then the I phase combined signal Yi The received signal is demodulated by combining the Q-phase combined signal Yq.

  In the above configuration, a transmission digital signal is output from the transmission digital signal output unit 16, the signal is modulated based on predetermined transmission information by the modulation unit 17, and then converted into an analog signal by the transmission signal D / A conversion unit 11. Is done. The frequency of the transmission signal converted into the analog signal is increased by the up-converter 14 by the frequency of the frequency conversion signal output from the frequency conversion signal output unit 13 and is supplied to the transmission antenna 1 and wirelessly transmitted as a transmission wave Fc. It is transmitted toward the tag circuit element To.

  When the transmission wave Fc from the transmission antenna 1 of the interrogator 100 is received by the antenna 151 of the RFID circuit element To, the transmission wave Fc is supplied to the modem 156 and demodulated. Further, a part of the transmission wave Fc is rectified by the rectification unit 152 and is used as an energy source (power source) by the power supply unit 153. With this power supply, the control unit 155 generates a reply signal based on the information signal of the memory unit 155, and the modulation / demodulation unit 156 modulates the transmission wave Fc based on the return signal, and the interrogator as the reflected wave Fr from the antenna 151. Reply to 100.

  When the reflected wave Fr from the antenna 151 of the RFID circuit element To is received by the receiving antennas 2A to 2C of the interrogator 100, the reflected wave Fr is supplied from the antennas 2A to 2C to the down converter 15 to receive each received signal. Is reduced by the frequency of the frequency conversion signal output from the frequency conversion signal output unit 13. The down-converted received signals are converted into digital signals by the corresponding received signal A / D converters 12.

  The digitally converted received signal is supplied to both the phased array control unit 200 and the adaptive array control unit 150 and processed in parallel (in detail, while switching the respective controls in cooperation as will be described later). In the phased array control unit 200, the receiving antennas 2A, 2B, and 2C are subjected to phased array processing that sequentially changes their directions while maintaining their directivities in predetermined directions, and the processed signals are subjected to amplitude detection. The amplitude is detected by the unit 220 and the detection result is input to the CPU 20. The adaptive array control unit 250 performs adaptive array processing for changing the directivity of the antennas 2A, 2B, and 2C so that the reception state with respect to the wireless tag T that is a communication target is optimal, and the reception after processing is performed. The signal is guided to the AM demodulator 30 to generate a demodulated signal. The demodulated signal is output from the AM demodulator 30 as an AM demodulated wave, and the data decoded by the FM decoder 40 is input to the CPU.

  The main part of the present embodiment, which is the basic configuration and operation described above, is a phased array that scans the antennas 2A to 2C as shown in FIG. 4 by sequentially changing the directions while maintaining their directivities in a predetermined direction. Control and adaptive array control that changes the directivity of the antennas 2A to 2C so as to optimize the reception state with respect to the RFID tag circuit element To that is the object of communication are used in parallel (selectively switched). In particular, it is to determine the weight (weight) for the adaptive array based on the directivity control result (= direction determination of the communication target) by the phased array control and generate the composite output signal. The details will be described below.

  FIG. 5 is a flowchart showing a control procedure of the received signal processing operation by the BB unit 10 which is a main part of the above operation. The flow on the right side of the drawing represents the procedure executed by the adaptive array control unit 250, and the flow on the left side of the drawing represents the procedure executed by the phased array control unit 200.

  First, in step S150, based on the control (instruction) of the CPU 20, first, the weighting control unit 252 of the adaptive array control unit 250 sets initial values of phases and amplitudes in the multiplication units 251a, 251b, and 251c.

  Thereafter, in step S200, based on the control (instruction) of the CPU 20, the adaptive array control unit 250 starts adaptive array processing (details will be described later), and the directivity generated by the antennas 2A, 2B, 2C is the received signal. The search is started while changing the weight (weight) by the weight control unit 252 so that the intensity becomes the maximum value, that is, the optimum sensitivity (refer to FIG. 6 described later for the detailed procedure).

  When the adaptive processing by the adaptive array control unit 250 is started in this way, the CPU 20 causes the (reception) directivities of the reception antennas 2A, 2B, and 2C used in the phased array control unit 200 to be unidirectional in step S100. When the direction is changed while being held (details will be described later), an initial value of a directivity angle (hereinafter referred to as a directivity angle) θ from a certain reference position is set.

  Thereafter, in step S101, the phases related to the receiving antennas 2A, 2B, and 2C are determined in the IF tables 201a, 201b, and 201c of the phased array control unit 200 according to the value of the directivity angle θ, and the phase control signal corresponding thereto Is output to the transfer devices 202a, 202b and 202c. Specifically, the phase difference between received signals at adjacent antennas of the received radio wave is expressed as follows: (2 · π · d · cosθ) /, where d is the interval between adjacent receive antennas, λ is the wavelength of the received radio wave, and θ is the directivity angle. Since λ, the corresponding phase difference is given to the transfer devices 202A to 2C from the IF tables 201a to 201c.

Thereafter, in step S102, the signal is a call signal from the antenna 1 to the search target wireless tag T under the condition that the phases of the antennas 2A, 2B, and 2C are set as described above (in other words, the directivity angle θ is set). A ScrollID signal is output. Specifically, based on the control signal from the CPU 20, the transmission digital signal generation unit 16 generates a transmission digital signal and outputs the transmission digital signal to the modulation unit 17. The modulation unit 17 performs the corresponding amplitude modulation and performs “Scroll”.
ID signal, analog-converted by the D / A converter 11, high-frequency converted by the up-converter 14, finally transmitted via the antenna 1, and from the RFID circuit element To of the RFID tag T to be searched Encourage replies.

  Thereafter, in step S103, a response signal (= reply signal; wireless tag information such as tag identification information) transmitted from the wireless tag circuit element To of the wireless tag T to be searched corresponding to the “Scroll ID” signal is sent to the antenna. 2A, 2B, and 2C, the phases are controlled by the transfer devices 202a, 202b, and 202c of the phased array control unit 200, and the phase is added to the amplitude detection unit 220 from the addition unit 203. At this time, the amplitude of the received signal is detected by the amplitude detector 220 and the value is taken into the CPU 20.

  Thereafter, the process proceeds to step S104, and it is determined whether or not the amplitude is equal to or greater than a predetermined threshold value (whether the directivity direction of the antennas 2A to 2C has approached the direction of the wireless tag T). If the determination is satisfied, the process proceeds to step S105.

  In step S105, in response to the directivity angle θ of the antennas 2A to 2C approaching the direction of the wireless tag T, the CPU 20 gives an instruction to update the weight in the adaptive processing to that corresponding to the directivity angle θ. Input to the weighting control unit 252 of the adaptive array control unit 250. When step S105 is completed, the process proceeds to step S106. In addition, also when the determination of above-mentioned step S104 is not satisfy | filled, it moves to this step S106.

  In step S106, it is determined whether or not θ is equal to θEND (for example, θEND = 180 °) set in advance as a final value when the directivity angle θ is sequentially changed. At first, θ is small, so the determination is not satisfied, and only θSTEP (for example, θSTEP = 30 °) predetermined in step S107 is added, and the process returns to step S101 and the same procedure is repeated.

  In this way, steps S101 to S107 are repeated to add θSTEP to the value of θ in small increments, while maintaining the directivity generated by all the antennas 2A, 2B, and 2C in a single direction while gradually changing the directivity angle θ. Repeating transmission and reception, each time the directivity angle θ of the antennas 2A to 2C is close to the direction of the wireless tag T and a relatively large amplitude is obtained, a weight update instruction is output in step S105. When θ = θEND, the determination in step S106 is satisfied, and the flow on the phased array control unit 200 side ends.

On the other hand, as described above, the adaptive array control unit 250 has already started and executed adaptive processing in step S200. However, each time the instruction in step S105 is received, the adaptive array control unit 250 updates the weight to a corresponding new value and performs convergence calculation. Continue (step S200A equivalent to step S200). When the convergence calculation with the updated weight is finished and the adaptive array processing in step S200A is finished, the process proceeds to step S151.

In step S151, the direction θT in which the wireless tag T exists is estimated based on the convergence result. At this time, when there is an interference signal source in the same direction as the wireless tag T, there is a case where a deviation occurs between the tag direction and the antenna directivity. Moreover, it may become directivity which shows maximum in several directions. For this reason, the direction of the tag is an estimated value or a probability value. As described above, adaptive array control is performed to change the directivity synthesized by the antennas 2A to 2C so that the reception sensitivity of the RFID circuit element To with respect to the antenna 151 is optimized, and the demodulation processing by the AM demodulator 30 is performed. The target RFID circuit element To is detected with high sensitivity.
Thereafter, in step S152, the reception signal adaptively processed by adaptive array control unit 250 is demodulated by AM demodulation unit 30, and finally converted into a decoded signal by FM decoding unit 40, and is included in the reception signals of antennas 2A to 2C. Predetermined wireless tag information (for example, tag identification information; tag ID) is analyzed and input as data to the CPU 20 and stored in appropriate storage means (memory) (step S153), and the flow on the adaptive array control unit 250 side Exit.

  FIG. 6 is a flowchart showing a detailed procedure of adaptive array processing executed by the adaptive array control unit 250.

  6, in step S201 and step S202, the ScrollID signal is output from the antenna 1 and the response signal transmitted from the RFID tag circuit element To of the RFID tag T to be searched is sent in the same manner as in steps S102 and S103 in FIG. The signals are received by the multipliers 251a, 251b, and 251c from the antennas 2A, 2B, and 2C, and are taken into the weighting controller 252 via the adder 253.

  Thereafter, in step S203, the weights related to the antennas 2A, 2B, and 2C are determined according to the signal strength value of the received signal input from the adder 253, and then the corresponding phase and amplitude (gain) are determined in step S204. And a phase control signal corresponding to this is output to the multipliers 251a, 251b, and 251c.

  The weight value at this time is stored in a memory (not shown) separately provided in the weight control unit 252 (or the CPU 20) and compared with the size stored so far, as will be described later. When the determination in step S205 is not satisfied and the calculation is repeated after returning to step S201, it is determined that the calculation has converged if the change is considered to be equal to or less than a predetermined value compared to the stored value. That is, the directivity generated by the antennas 2A, 2B, and 2C is sought so that the received signal intensity becomes the maximum value, that is, the optimum sensitivity. In addition, when a jamming signal is detected, the directivity is further optimized so that the jamming signal becomes small. If the weight value is substantially constant and the calculation converges, the determination in step S205 is satisfied. If not, the determination is not satisfied, and the process returns to step S201 and the same calculation procedure is repeated.

  As described above, when the directivity with the optimum reception sensitivity is found for each of the antennas 2A, 2B, and 2C by repeating step S201 → step S202 → step S203 → step S204 → step S205 → step S201 →. Thus, the determination in step S205 is satisfied, and this flow ends.

  In the above, the BB unit 10 including the phased array control unit 200, the adaptive array control unit 240, the CPU 20, etc. selectively switches between the first control unit and the second control unit according to the claims, and a plurality of antenna elements The directivity control means for controlling the directivity of the first control means is configured, and the weighting control unit 252 weights the synthesized output signal to be demodulated closer to the target signal according to the directivity control result in the first control means. Weighting determination means for determining the output, and the multipliers 251a to 251c, the adder 253, and the filter processing unit (not shown) generate a combined output signal using the weights determined by the weighting determination means. Configure.

  Further, the CPU 20 constitutes a computing means, and the IF tables 201a to 201c constitute a first weight determining means for determining the first weight for the first control based on the phase control signal from the computing means, and the phase shift The units 202a to 202c and the adding unit 203 constitute first synthesized output signal generating means for generating a first synthesized output signal for first control using the first weight determined by the first weight determining means. The weighting control unit 252 constitutes a second weight determining unit that determines a second weight for the second control based on the phase / amplitude control signal from the calculating unit, and the multiplying units 251a to 251c and the adding unit 253 include Second synthesized output signal generating means for generating a second synthesized output signal for second control using the second weight determined by the second weight determining means is configured.

  Further, the AM demodulator 30 constitutes a demodulator that demodulates the combined output signal generated by the combined output signal generator or a signal based on the combined output signal.

  In the interrogator 100 of the present embodiment configured as described above, in the BB unit 100, the antennas 2A to 2C in the phased array control unit 200 are based on the control signal from the CPU as described above with reference to FIG. The first tag (phased array control) that sequentially changes the direction while maintaining the directivity in a predetermined direction, and the reception signals of the antennas 2A to 2C in the adaptive array control unit 250 are brought close to the reference signal r, thereby the RFID tag T The antenna directivity control is performed while simultaneously switching the second control (adaptive array control) for changing the reception state to be optimal with simultaneous parallel processing.

  As a result, the reception direction determination performance by phased array control and the reception sensitivity improvement performance by adaptive array control can be cooperated, so that the direction of the wireless tag T is determined in a relatively short time and the reception sensitivity with respect to that direction is determined. Can be improved. In particular, by performing reception state optimization control (adaptive array control) in the adaptive array control unit 250 based on the directivity control (phased array control) result in the phased array control unit 200, the RFID tag T of the phased array control is controlled. Based on the direction determination, adaptive state control is performed to perform reception state optimization control in that direction. Specifically, the weighting control unit 252 determines a weight (weight) based on the directivity control result (= determination of the direction of the wireless tag T) in the phased array control unit 200 (step S203 of step S200A), and uses the weighting. As a result, the multipliers 251a to 251c generate the composite output signal, thereby realizing adaptive array control utilizing the result of the phased array control. As a result, it is possible to obtain high reception sensitivity in a relatively short time compared to the case of only adaptive array control.

  In the present embodiment, as shown in FIG. 5, the phased array control and the adaptive array control are executed almost simultaneously. Normally, the loop calculation until convergence is performed in the adaptive array processing is the state of the interference wave. Or, depending on the modulation degree of the response wave of the wireless tag T, it is necessary to perform the operation several tens of thousands of times. Therefore, in this embodiment, θ is successively changed in the phased array process to use the time during which the arrival direction of the response wave from the wireless tag T is detected, and the adaptive process is simultaneously performed during that time (see FIG. 5). Thus, there is also an effect that the adaptive array processing can be sufficiently completed in the time required for performing the phased array processing, and the time can be effectively used to prevent the processing time from increasing.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit and technical idea of the present invention. Hereinafter, such modifications will be described.

(1) Partial sharing of phased array control unit and adaptive array control unit Rather than separately providing phased array control unit 200 and adaptive array control unit 250 as in the above embodiment, a part of circuit configuration is shared. It is also possible to do. FIG. 7 is a functional block diagram showing a detailed configuration of the BB section 10 ′ of the interrogator in such a modification. Components equivalent to those in FIG. 3 are denoted by the same reference numerals, and description thereof will be simplified or omitted as appropriate.

  As described above, in the BB unit 10 ′, the phase and amplitude of the received radio wave signal at the receiving antennas 2A, 2B, and 2C are variably set as a common configuration in the phased array control unit 200 and the adaptive array control unit 250. 3 and the frequency conversions from the frequency conversion signal output unit 13 and the multiplication units 301a, 301b, and 301c that function as the functions of the phase shifters 202a, 202b, and 202c and the functions of the multiplication units 251a, 251b, and 251c in FIG. Based on the signal (clock signal SCLK), the multipliers 301a to 301c selectively switch one of the two functions for each predetermined minute time interval (see FIG. 8 described later) in synchronization therewith. Outputs from the selectors 302a, 302b, 302c and the multipliers 301a, 301b, 301c And an adding unit 303 for summing. The output from the adding unit 303 is supplied to a newly provided changeover switch 304. The changeover switch 304 receives the frequency conversion signal (clock signal SCLK) from the frequency conversion signal output unit 13 in the same manner as described above, and in synchronism with this, the addition unit 303 is provided for each predetermined minute time interval (see FIG. 8 described later). Is selectively output to the AM demodulator 30 or the amplitude detector 220.

  FIG. 8 is a time chart showing the selection switching operation in the selectors 302 a to 302 c and the changeover switch 304. As shown in FIG. 8, in this example, the A / D converters 12a to 12a synchronized with the frequency conversion signal (A / D conversion sampling clock signal SCLK) from the frequency conversion signal output unit 13 as the predetermined time section. The sampling time of 12c is used as a unit. The sampling time is divided into two, and the first half is a slot for adaptive array control (second time section), and the second half is a slot for phased array control (first time section). Apparently, phased array control and adaptive array control and simultaneous processing are realized.

  That is, when the frequency conversion signal (clock signal SCLK) from the frequency conversion signal output unit 13 is a “LOW” signal, it corresponds to the adaptive array control slot, and the selectors 302 a to 302 c are connected to the weight control unit 252. Are selected and led to the multipliers 301a to 301c. The changeover switch 304 is switched so as to introduce the signal (SUM signal) from the adder 303 to the AM demodulator 30 side.

  As a result, the multiplication units 301a, 301b, and 301c function as the functions of the adaptive array control unit 250, equivalent to the multiplication units 251a, 251b, and 251c in FIG. That is, the weighting control unit 252 optimizes the reception sensitivity of the antennas 2A to 2C with respect to the direction in which the wireless tag T is arranged with respect to the combined output signal added by the adding unit 303 (= wireless tag). The directivity is controlled by changing the amplitude and phase of each of the received signals received by the antennas 2A to 2C (so that the amplitude of the modulation component by the circuit element To is made as high as possible and approaches the reference signal r). For this purpose, predetermined weighting is performed for each of the antennas 2A, 2B, and 2C in the phase control signals to the multipliers 301a to 301c, and convergence calculation is repeatedly performed while changing the weighting (weight). The received signals adaptively processed by the multipliers 301 a to 301 c by the control signal of the weight control unit 252 are added together by the adder 303 and then input to the AM demodulator 30 via the changeover switch 304.

  On the other hand, when the frequency conversion signal (clock signal SCLK) from the frequency conversion signal output unit 13 is a “HIGH” signal, it corresponds to the phased array control slot, and the selectors 302a to 302c are connected to the IF tables 201a to 201c. The control signal (weight) from is selected and led to the multipliers 301a to 301c. The changeover switch 304 is switched so as to introduce the signal (SUM signal) from the addition unit 303 to the amplitude control unit 220 side.

  As a result, the multipliers 301a, 301b, and 301c perform the same functions as the phase shifters 202a, 202b, and 202c in FIG. That is, the data values of the IF tables 201a, 201b, and 201c corresponding to the phase control signal from the CPU 20 are input to the multipliers 301a, 301b, and 301c, and the multipliers 301a to 301c refer to the data to receive antenna 2A, The phase of the received radio signal at 2B and 2C is set to be variable. As a result, phased array processing is performed for the receiving antennas 2A, 2B, and 2C while sequentially changing their directions while maintaining their directivities in a predetermined direction, and the signals after processing are switched by the adder 303 after addition. The amplitude is detected by the amplitude detector 220 via the switch 304, and the detection result is input to the CPU 20.

  In the above, each of the multipliers 301a, 301b, and 301c constitutes one combined output signal generating unit in which the first combined output signal generating unit and the second combined output signal generating unit are shared, and the selector 302a, 302b, and 302c constitute switching means for selectively switching and inputting the weights determined by the first or second weight determination means to a single combined output signal generation means.

  Also by this modification, the same effect as the above-mentioned embodiment is acquired. In addition, by using the multipliers 301a to 301c and the adder 303 in common in the phased array control and the adaptive array control, the configuration of the entire apparatus can be simplified and the cost can be reduced.

  In the above, the time division is fixed as shown in FIG. 8, and the first half of each AD conversion sampling time is an adaptive array and the latter half is a phased array. However, the distribution is not limited to this, and the distribution is variable. Also good.

  FIG. 9 is a functional block diagram showing a detailed configuration of the BB section 10 ″ of the interrogator in such a modification. The same parts as those in FIG. 7 are denoted by the same reference numerals, and the description will be simplified or omitted as appropriate. To do.

  In this BB unit 10 ″, a selection signal generation unit 305 is newly provided. The selection signal generation unit 305 performs adaptive array processing in synchronization with the frequency conversion signal (clock signal SCLK) from the frequency conversion signal output unit 13. A selection signal (SELCK) for selecting the phased array processing is generated, and the selectors 302a, 302b, 302c and the changeover switch 304 are controlled in the selection switching operation according to the selection signal.

  FIG. 10 is a diagram illustrating a generation mode of the selection signal in the selection signal generation unit 305. In FIG. 10, the selection signal generation unit 305 performs time division into two parts, the first half and the second half, with the AD conversion sampling time as a unit, as in FIG. 8 described above. The adaptive array slot or the phased array slot can be freely changed.

  In the example of FIG. 10, the pattern A shows the same switching mode as described above, the first half of each AD conversion sampling time is an adaptive array slot, and the selectors 302 a to 302 c select the weight from the weight control unit 252. The selector switch 304 generates and outputs a selection signal that introduces the signal from the adder 303 to the AM demodulator 30 and leads to the multipliers 301a to 301c. The second half of each AD conversion sampling time is a phased array slot. The selectors 302a to 302c select control signals from the IF tables 201a to 201c and guide them to the multipliers 301a to 301c. A selection signal that introduces the signal to the amplitude control unit 220 side is generated and output. As a result, as shown in the figure, the processing ratio of adaptive array control and phased array control is 1: 1.

  On the other hand, in the pattern B as an example, three AD conversion sampling times are set as one cycle, and the first sampling time (corresponding to the counter value 0) is the first half as an adaptive array slot and the second half is the same as above. A selection signal for generating a phased array slot is generated, and a selection signal for generating an adaptive array slot for the first half and the second half is generated for the second sampling time (corresponding to the counter value 1), and the third sampling time (counter For the value 2), a selection signal is generated so that the first half and the second half are adaptive array slots, and this cycle is repeated. As a result, as shown in the figure, the processing ratio of adaptive array control and phased array control is 1: 5.

  In the above, the selection signal generation unit 305 inputs the weight determined by the first weight determination unit in the first time segment to one combined output signal generation unit, and the second weight in the second time segment. The switching control means for controlling the switching operation of the switching means is configured so that the weight determined by the determining means is input to the common combined output signal generating means.

  In the present modification, the selection signal generation unit 305 can change the ratio of the adaptive array control process and the phased array control process as described above. This ratio can be set by an instruction signal from the CPU 20, for example. In general, adaptive array control usually takes more processing time than phased array control, so it is preferable to increase the ratio of adaptive array control.

  Note that the slot width itself may be variably set instead of changing the distribution only by fixing the slot width as described above. In this case, the ratio between the first half slot and the second half slot occupying the sampling time unit of AD conversion is variably set, and the time distribution between the phased array control and the adaptive array control can be determined more freely.

(2) When Adaptive Array Control is Performed After Completion of Phased Array Control In the above embodiment, as shown in FIG. 5, the phased array control in phased array control unit 200 and the adaptive array control in adaptive array control unit 250 are almost the same. However, the present invention is not limited to this, and the detection sensitivity may be improved by adaptive array control after detecting the direction of the wireless tag T by phased array control and completing the control.

  FIG. 11 is a flowchart showing the control procedure of the received signal processing operation by the BB unit 10 of the interrogator in such a modification, and corresponds to FIG. Portions and procedures equivalent to those in the above embodiment are denoted by the same reference numerals, and description thereof is omitted or simplified as appropriate.

  11, first, in step S100 similar to FIG. 5, the CPU 200 sets the initial value of the directivity angle θ used in the phased array control unit 200, and then in step S150, the weighting control unit 252 of the adaptive array control unit 250. Sets initial values of phase and amplitude in the multipliers 251a, 251b, and 251c.

  Thereafter, steps S101 to S104 are the same flow as in FIG. 5, and the phases related to the receiving antennas 2A, 2B, and 2C are determined in the IF tables 201a, 201b, and 201c according to the value of the directivity angle θ, and the corresponding phase control signals are displayed. It outputs to the transfer devices 202a, 202b, 202c, outputs a ScrollID signal from the antenna 1, and receives a response signal from the antennas 2A, 2B, 2C. The transfer devices 202a, 202b and 202c of the phased array control unit 200 control the phase of the received signal, and the amplitude detection unit 220 detects the amplitude of the received signal, and whether the amplitude is equal to or greater than a predetermined threshold (antenna It is determined whether or not the directing directions of 2A to 2C have approached the direction of the wireless tag T).

  When determination is not satisfy | filled, it moves to below-mentioned step S106. When the determination is satisfied, the process proceeds to step S200 (refer to FIG. 6 for the detailed procedure). Similarly to the above, the adaptive array control unit 250 performs adaptive array processing, and the directivity generated by the antennas 2A, 2B, 2C is the received signal. The weighting control unit 252 searches for the intensity while changing the weight (weight) so that the intensity becomes the maximum value, that is, the optimum sensitivity (refer to FIG. 6 described above for the detailed procedure). At this time, the received signal is input to the CPU 20 via the AM demodulating unit 30 and the FM decoding unit 40 as described above. In the next step S108, the CPU 20 can normally decode the received signal by the FM decoding unit 40. Is determined.

  If the decoding is successful, the determination in step S108 is satisfied, and the process proceeds to step S109 where the direction of the decoded reception signal is the original signal (desired wave) from the communication target (wireless tag T) that is desired to be received. This direction is used as a so-called tag point in the subsequent control (a flag to that effect may be set). If the decoding cannot be performed, the determination in step S108 is not satisfied, and the process proceeds to step S110 where the direction of the decoded reception signal is a disturbing wave direction (for example, the wireless tag T) different from the communication target (wireless tag T) to be received. This signal is assumed to be a so-called null point in the subsequent control (such as setting a flag to that effect). Also good).

  When step S109 or step S110 ends, the process proceeds to step S106 similar to FIG. 5, and it is determined whether or not θ is equal to θEND. If the determination is not satisfied, θSTEP is added in step S107, the process returns to step S101, and the same procedure is repeated.

  In this way, steps S101 to S107 are repeated to add θSTEP to the value of θ in small increments, while maintaining the directivity generated by all the antennas 2A, 2B, and 2C in a single direction while gradually changing the directivity angle θ. While the transmission and reception are repeated, while the directivity angle θ of the antennas 2A to 2C is close to the direction of the wireless tag T and a relatively large amplitude is obtained, adaptive array processing is performed in step S200, and step S108, step each time. In S109 and step S110, the processing is continued while the desired wave direction is defined while the desired wave direction and the disturbing wave direction are identified. If θ = θEND, the determination in step S106 is satisfied, the flow on the phased array control unit 200 side ends, and the process proceeds to step S200B.

  In step S200B, the optimum weights that roughly define the desired wave in advance as described above are used, and as in steps S200 and S200A, more reliable adaptive array processing is performed, and the directivity generated by the antennas 2A, 2B, and 2C. Sought to maximize the received signal strength, that is, the optimum sensitivity

  Thereafter, the processing is the same as in FIG. 5, and when the convergence calculation by weight is completed and the adaptive array processing in step S200A is completed, the process proceeds to step S151.

  In step S151, the existence direction θT of the RFID tag T is estimated based on the convergence result, and in step S152, the received signal is demodulated by the AM demodulator 30 and finally decoded by the FM decoder 40 and analyzed. The wireless tag information is input to the CPU 20 and stored in the storage means (step S153), and this flow is finished.

  In the above, step S108, step S109, and step S110 indicate whether or not signals received by a plurality of antenna elements are transmission waves from the communication target, according to the demodulation result of the demodulator according to each claim. A discrimination means for discriminating is configured.

  Also in this modified example, similarly to the above-described embodiment, the reception direction determination performance by phased array control and the reception sensitivity improvement performance by adaptive array control cooperate, and adaptive array control is performed based on the direction determination of the RFID tag T by phased array control. Since the reception state optimization control in that direction is performed, the direction of the wireless tag T can be determined in a relatively short time and the reception sensitivity in that direction can be improved.

  Further, in this modified example, after identifying in advance in step S108 to step S110 whether it is a transmission wave or an interference wave, weighting is performed with an optimum weight based on the result in subsequent step S200B, as shown in FIG. In addition, the weighting is determined so that the reception sensitivity is increased in the direction of the transmission wave from the RFID tag T that is the communication target, and the reception sensitivity is decreased in the direction other than the transmission wave direction (interference wave direction). The received signal strength with respect to the wave can be improved quickly and reliably. As a result, a high received signal strength with respect to the transmission wave can be obtained in a relatively short time.

  In the above modification, it is not limited to determining whether the AM demodulating unit 30 and the FM decoding unit can demodulate and decode in step S108 in FIG. Even if it does not necessarily perform decoding, it may be determined whether it is a desired wave or an interference wave depending on whether the pulse width falls within a predetermined range (within the standard) in the state of the pulse before decoding. When the signal is out of the range, it is not a signal from the wireless tag T and can be regarded as an interference wave.

  In the above, the phased array control unit 200 and the adaptive array control unit 250 that operate based on the control of the common CPU 20 are provided in one BB unit 10, and these controls are selectively switched or simultaneously performed. However, the present invention is not limited to this. That is, for example, the phased array control unit 200 and the adaptive array control unit 250 may be configured by independent separate CPUs, separate hardware circuits, or the like so as to perform completely parallel and simultaneous processing. In this case, the same effect is obtained.

  In the above description, the AM demodulating unit 30, the FM decoding unit 40, the adaptive array control unit 200, and the phased array control unit 260 are provided in the BB unit 10, but they are different from the BB unit 10. The body may be provided as an independent control device.

  In the above, the interrogator 100 includes the transmission antenna 1 that transmits the transmission wave Fc toward the RFID circuit element To, and the reception antennas 2A to 2A that receive the reflected wave Fr returned from the RFID circuit element To. 2C is provided as a separate body, but the present invention is not limited to this, and a transmission / reception antenna that transmits a transmission wave Fc toward the RFID circuit element To and receives a reflected wave Fr returned from the RFID circuit element To It may be provided with. In this case, a transmission / reception separator such as a circulator is provided corresponding to the transmission / reception antenna.

  Furthermore, in the above description, the interrogator 100 has been used as an interrogator in the communication system S of FIG. 1, but the present invention is not limited to this, and the present invention writes predetermined information to the RFID circuit element To and uses the RFID tag. The present invention is also suitably applied to a wireless tag creation device that creates T and a wireless tag reader / writer that reads and writes information.

  In addition, although not illustrated one by one, the present invention is implemented with various modifications within a range not departing from the gist thereof.

1 is a system configuration diagram illustrating an overall outline of a wireless tag communication system to which an embodiment of the present invention is applied. It is a block diagram showing an example of a functional structure of the radio | wireless tag circuit element with which the radio | wireless tag was equipped. It is a functional block diagram showing the functional structure of the interrogator shown in FIG. It is explanatory drawing showing the behavior of phased array control. It is a flowchart showing the control procedure of the received signal processing operation by BB part. It is a flowchart showing the detailed procedure of the adaptive array process performed with an adaptive array control part. It is a functional block diagram showing the detailed structure of the BB part of the interrogator in the modification which shared a part of phased array control part and adaptive array control part. It is a time chart showing the selection switching operation in the selector and changeover switch shown in FIG. It is a functional block diagram showing the detailed structure of the BB part of the interrogator in the modification which made variable distribution of minute time divisions. It is a figure showing the production | generation aspect of the selection signal in the selection signal production | generation part shown in FIG. It is a flowchart showing the control procedure of the received signal processing operation by BB part of an interrogator in the modification which performs adaptive array control after completion of phased array control. It is explanatory drawing showing the behavior of adaptive array control.

Explanation of symbols

2A ~ C Antenna (antenna element)
10 BB section (directivity control means)
20 CPU (calculation means)
30 AM demodulator (demodulator)
200 Phased array controller (first control means)
201a-c IF table (first weight determining means)
202a-c phase shifter (first synthesized output signal generating means)
203 Adder (first synthesized output signal generating means)
250 Adaptive array controller (second control means)
251a-c Multiplier (second synthesized output signal generating means, synthesized output signal generating means)
252 Weighting control unit (second weight determining means, weight determining means)
253 Adder (second synthesized output signal generating means, synthesized output signal generating means)
301a-c Multiplying unit (one combined output signal generating means common)
302a-c selector (switching means)
305 Selection signal generator (switching control means)
T wireless tag (communication target)

Claims (12)

A plurality of antenna elements for receiving transmission waves from a communication target via wireless communication;
First control means for performing a first control to sequentially change the direction of the plurality of antenna elements while maintaining their directivity in a predetermined direction;
Second control means for performing second control for changing the directivity of the plurality of antenna elements so that a reception state with respect to the communication target is optimized;
A radio receiving apparatus comprising: directivity control means for controlling directivity of the plurality of antenna elements by the first control means and the second control means. The wireless receiver according to claim 1,
The directivity control means controls the directivity of the plurality of antenna elements by selectively switching between the first control means and the second control means. The wireless receiver according to claim 1 or 2,
The radio directivity apparatus wherein the directivity control means performs reception state optimization control in the second control means based on a directivity control result in the first control means. The wireless receiver according to claim 3, wherein
The directivity control means includes
Weighting determining means for determining weighting so that a composite output signal to be demodulated approaches a target signal according to a result of directivity control in the first control means;
And a combined output signal generating unit configured to generate the combined output signal using the weight determined by the weight determining unit. The wireless receiver according to claim 4, wherein
A radio receiving apparatus comprising demodulating means for demodulating the synthesized output signal generated by the synthesized output signal generating means or a signal based thereon. The wireless receiver according to claim 5, wherein
The directivity control means includes determination means for determining whether signals received by the plurality of antenna elements are transmission waves from the communication target, according to a demodulation result of the demodulation means,
The wireless weighting apparatus characterized in that the weighting determination means determines the weighting based on a determination result of the determination means. The wireless receiver according to claim 6, wherein
The weight determination means performs the weighting so that the reception sensitivity increases in a direction determined as the transmission wave by the determination means, and the reception sensitivity decreases in a direction determined as not the transmission wave. A radio receiving apparatus characterized by determining. The wireless receiver according to any one of claims 1 to 3,
The directivity control means includes
Computing means;
First weight determining means for determining a first weight for the first control based on a phase control signal from the calculating means;
First synthesized output signal generating means for generating a first synthesized output signal for the first control using the first weight determined by the first weight determining means;
Second weight determining means for determining a second weight for the second control based on a phase / amplitude control signal from the computing means;
And a second combined output signal generating unit configured to generate a second combined output signal for the second control using the second weight determined by the second weight determining unit. The wireless receiver according to claim 8, wherein
The first synthesized output signal generating means and the second synthesized output signal generating means are shared by one synthesized output signal generating means,
The common combined output signal generating means generates the first or second combined output signal for the first or second control using the weight determined by the first or second weight determining means. A wireless receiver characterized by: The wireless receiver according to claim 9, wherein
The directivity control means includes switching means for selectively switching and inputting the weights determined by the first or second weight determination means to the single combined output signal generation means. Wireless receiver. The wireless receiver according to claim 10, wherein
The directivity control unit divides a predetermined minute time unit into a first time segment and a second time segment, and the weight determined by the first weight determination unit in the first time segment is the common 1 The switching means so that the weights determined by the second weight determining means are input to the common combined output signal generating means in the second time interval. A radio receiving apparatus comprising switching control means for controlling a switching operation. The wireless receiver according to claim 11, wherein
The radio reception apparatus, wherein the switching control means can variably set the first time segment and the second time segment.

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