JP2006050368A - Wireless receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless receiver capable of performing directivity control as quickly as possible. <P>SOLUTION: The receiver comprises a PAA weight control unit 54 for controlling the directivity of reception signals received by a plurality of reception antenna elements 26 by phased array processing; an AAA weight control unit 56 for controlling the directivity of the reception signals received by the plurality of reception antenna elements 26 by adaptive array processing; a reception signal strength determining unit 50 for determining whether or not the reception signals received by the plurality of reception antenna elements 26 have predetermined quality; and a directivity control switching unit 60 for switching so that the unit 54 first controls the directivity of the reception signals, and then, if the determination of the unit 50 is denied, the unit 56 controls the directivity of the reception signals. Thus, the adaptive array processing is performed when it is required, thereby eliminating an unnecessary calculation. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an improvement of a radio reception apparatus including a plurality of reception antenna elements for receiving a signal transmitted from a predetermined communication target.

  2. Description of the Related Art An RFID (Radio Frequency Identification) system is known in which information is read out in a non-contact manner by a predetermined wireless tag communication device (interrogator) from a small wireless tag (responder) that stores predetermined information. This RFID system is capable of reading information stored in a wireless tag by communication with the wireless tag communication device even when the wireless tag is dirty or disposed at an invisible position. Therefore, practical use is expected in various fields such as merchandise management and inspection processes.

  As one aspect of such a wireless tag communication apparatus, the wireless tag communication apparatus includes a plurality of receiving antenna elements for receiving a signal transmitted from a wireless tag that is a communication target, and has directivity for performing communication in accordance with the direction of the wireless tag. What performs control is known. For example, this is the wireless device described in Patent Document 1. According to this radio apparatus, since the array antenna includes a plurality of antenna elements, and an adaptive processing unit that multiplies each received signal received by the plurality of antenna elements by a weight, Directivity can be suitably determined, and suitable communication can be performed with a wireless tag that is a communication target.

JP 2003-283411 A

  However, in the directivity control by general AAA (Adaptive Array Antenna) processing as in the conventional technique, it is necessary to calculate the weight given to each of a plurality of antenna elements by a predetermined adaptive processing algorithm. There was an adverse effect of increasing the amount of time and processing. That is, the development of a radio receiver capable of performing directivity control as quickly as possible has been demanded.

  The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a radio receiving apparatus capable of performing directivity control as quickly as possible.

  In order to achieve such an object, the gist of the present invention is a wireless reception apparatus including a plurality of reception antenna elements for receiving a signal transmitted from a predetermined communication target, A phased array control unit that controls the directivity of the received signal received by the receiving antenna element by phased array processing, and an adaptive array control that controls the directivity of the received signal received by the plurality of receiving antenna elements by adaptive array processing A reception quality determination unit that determines whether or not a reception signal received by the plurality of reception antenna elements has a predetermined quality, and controls the directivity of the reception signal by the phased array control unit, If the determination by the reception quality determination unit is negative, directivity of the received signal is determined by the adaptive array control unit. And a directivity control switching unit that switches to control and is characterized in that it comprises.

  With this configuration, the phased array control unit that controls the directivity of the reception signals received by the plurality of reception antenna elements by phased array processing, and the directivity of the reception signals received by the plurality of reception antenna elements. An adaptive array control unit that controls by adaptive array processing, a reception quality determination unit that determines whether or not a reception signal received by the plurality of reception antenna elements has a predetermined quality, and first, the phased array control unit A directivity control switching unit that controls the directivity of the received signal and switches the adaptive array control unit to control the directivity of the received signal when the determination of the reception quality determination unit is negative; Therefore, unnecessary calculations are performed by performing adaptive array processing only when necessary. Finished, it is possible to shorten the processing time of the received signal. That is, it is possible to provide a radio reception apparatus that can perform directivity control as quickly as possible.

  Here, preferably, the adaptive array control unit determines an initial value of a weight to be given to each reception signal received by the plurality of reception antenna elements based on a control result by the phased array control unit. In this way, the time required for adaptive array processing can be further shortened.

  Preferably, the directivity control switching unit first sets the directivity of reception signals received by the plurality of reception antenna elements as an initial setting, and when the determination of the reception quality determination unit is denied. The phased array control unit switches so as to control the directivity of the received signal. In this way, it is possible to further shorten the processing time of the received signal.

  Preferably, the reception quality determination unit is a reception signal strength determination unit that determines whether the signal strength of the reception signal is equal to or higher than a predetermined value, and the determination of the reception signal strength determination unit is denied. In the case of the determination, the determination is denied. In this way, the quality of the received signal can be determined in a practical manner.

  Preferably, the reception quality determination unit is an interference wave determination unit that determines whether or not an interference wave is included in the received signal, and when the determination of the interference wave determination unit is affirmed, The determination is denied. In this way, the quality of the received signal can be determined in a practical manner.

  In addition, preferably, it includes a decoding unit that decodes the received signal, and the reception quality determining unit is an error determining unit that determines whether or not the decoding quality of the received signal by the decoding unit is within a predetermined range. If the determination by the error determination unit is negative, the determination is denied. In this way, the quality of the received signal can be determined in a practical manner.

  Preferably, the communication target is a wireless tag that can return the signal in response to a predetermined transmission signal. If it does in this way, the radio | wireless receiver which can perform directivity control as quickly as possible regarding the radio | wireless tag communication apparatus which communicates information with the said radio | wireless tag can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram for explaining a communication system 10 in which the wireless reception apparatus of the present invention is preferably used. The communication system 10 includes a wireless tag communication device 12 in which a wireless reception device 62 according to an embodiment of the present invention is incorporated, and a single or a plurality of communication targets of the wireless tag communication device 12 (single in FIG. 1). The RFID tag is a so-called RFID (Radio Frequency Identification) system. 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 _c (transmission signal) is transmitted from the radio tag communication apparatus 12 toward the radio tag 14, a predetermined information signal (data) is received in the radio tag 14 that has received the interrogation wave F _c. As a result, the interrogation wave F _c is modulated and sent back to the RFID tag communication apparatus 12 as a response wave F _r (reply signal), so that information is transmitted between the RFID tag communication apparatus 12 and the RFID tag 14. Communication takes place.

FIG. 2 is a diagram illustrating the configuration of the wireless tag communication device 12. As shown in FIG. 2, the wireless tag communication device 12 communicates information with the wireless tag 14 in order to read / write information with respect to the wireless tag 14 and detect the direction of the wireless tag 14. A DSP (Digital Signal Processor) 16 for executing a digital signal processing such as outputting a transmission signal as a digital signal or demodulating a return signal from the wireless tag 14, and output by the DSP 16. A transmission signal D / A converter 18 that converts a transmission signal into an analog signal, a frequency conversion signal output unit 20 that outputs a predetermined frequency conversion signal, and an analog signal converted by the transmission signal D / A converter 18 An up-converter 22 for increasing the frequency of the transmission signal by the frequency of the frequency conversion signal output from the frequency conversion signal output unit 20; A transmitting antenna element 24 to transmit it to the wireless tag 14 upconverted transmission signal as interrogating wave F _c by upconverter 22, the response wave returned from the wireless tag 14 in response to the interrogation wave F _c A plurality (three in FIG. 2) of receiving antenna elements 26a, 26b, and 26c (hereinafter simply referred to as receiving antenna elements 26 unless otherwise distinguished) for receiving F _r are received by the receiving antenna elements 26. A plurality of (three in FIG. 2) down-converters 28a, 28b, and 28c (hereinafter, particularly, the frequency conversion signal output unit 20 converts the frequency of each received signal to a frequency lower than the frequency conversion signal output from the frequency conversion signal output unit 20) If they are not distinguished, they are simply referred to as downconverters 28), and the outputs from these downconverters 28 are respectively. A plurality (three in FIG. 2) of received signal A / D converters 30a, 30b, and 30c for converting the down-converted received signal into digital signals (hereinafter simply referred to as received signal A / D conversion unless otherwise distinguished) And a storage device that stores the received signals converted into digital signals by the received signal A / D converter 30 and causes the DSP 16 to output the received signals in response to a command from the DSP 16. A memory unit 32 is provided.

  The DSP 16 is a so-called microcomputer system that includes a CPU, a ROM, a RAM, and the like, and performs signal processing according to a program stored in advance in the ROM while using a temporary storage function of the RAM. A transmission bit string generation unit 34 that generates a command bit string corresponding to the FSK method, a FSK encoding unit 36 that encodes a digital signal output from the transmission bit string generation unit 34 by the FSK method, and an encoding by the FSK encoding unit 36 The AM modulation unit 38 that modulates the received signal by the AM method and supplies the modulated signal to the transmission signal D / A conversion unit 18, and the PAA weight or AAA weight calculated by the weight control unit 52 is received by the plurality of reception antenna elements 26. Multiple (3 in FIG. 2) weight multiplications for each received signal received 40a, 40b, 40c (hereinafter simply referred to as the weight multiplication unit 40 unless otherwise distinguished), and a reception signal synthesis unit 42 that synthesizes (adds) the reception signals multiplied by the weights by the weight multiplication unit 40, respectively. The AM demodulator 44 that detects the AM demodulated wave by demodulating the synthesized signal synthesized by the received signal synthesizer 42 by the AM system, and the AM demodulated wave demodulated by the AM demodulator 44 is decoded by the FSK system. An FSK decoding unit 46; a response bit string interpretation unit 48 that interprets a decoded signal decoded by the FSK decoding unit 46 and reads an information signal related to modulation of the wireless tag 14; and an AM demodulation output from the AM demodulation unit 44 The received signal strength determination unit 50 that detects the received signal strength based on the wave and the received signal in each of the plurality of weight multiplication units 40 A weight control unit 52 for controlling the weights to be multiplied, a PAA weight control unit 54 for controlling PAA (Phased Array Antenna) weights included in the weight control unit 52, and AAA ( Adaptive Array Antenna) AAA weight control unit 56 for controlling the weight, reference signal generation unit 58 for supplying a reference signal to the AAA weight control unit 56, and any one of the PAA weight control unit 54 and the AAA weight control unit 56 On the other hand, there is functionally provided a directivity control switching unit 60 that switches so that weights supplied to the plurality of weight multiplication units 40 are controlled. In the RFID tag communication apparatus 12, the reception antenna element 26, down converter 28, reception signal A / D conversion unit 30, memory unit 32, weight multiplication unit 40, reception signal synthesis unit 42, AM demodulation unit 44, FSK decoding Unit 46, response bit string interpretation unit 48, received signal strength determination unit 50, weight control unit 52, PAA weight control unit 54, AAA weight control unit 56, reference signal generation unit 58, and directivity control switching unit 60 are wireless receivers. 62 is constituted.

FIG. 3 is a diagram for explaining the configuration of the wireless tag 14. As shown in FIG. 3, the wireless tag 14 includes an antenna unit 64 for transmitting and receiving signals to and from the wireless tag communication device 12 and a signal received by the antenna unit 64. The IC circuit unit 66 is provided. The IC circuit unit 66 rectifies the interrogation wave F _c received from the RFID tag communication apparatus 12 received by the antenna unit 64 and the energy of the interrogation wave F _c rectified by the rectification unit 68. Functions as a power supply unit 70 for accumulation, a clock extraction unit 72 that extracts a clock signal from the carrier wave received by the antenna unit 64 and supplies the clock signal to the control unit 78, and an information storage unit that can store a predetermined information signal The wireless tag 14 via the memory unit 74, the modulation / demodulation unit 76 connected to the antenna unit 64 for modulating and demodulating the signal, the rectification unit 68, the clock extraction unit 72, the modulation / demodulation unit 76, and the like. And a control unit 78 for controlling the function. The control unit 78 performs control for storing the predetermined information in the memory unit 74 by communicating with the RFID tag communication device 12, and the modulation / demodulation unit 76 receives the interrogation wave F _c received by the antenna unit 64. Then, basic control such as control for reflecting and returning the response wave _Fr as the response wave _Fr is executed based on the information signal stored in the memory unit 74.

  Returning to FIG. 2, the PAA weight controller 54 functions as a phased array controller that controls the directivity of the received signals received by the plurality of receiving antenna elements 26 by phased array processing. The AAA weight control unit 56 functions as an adaptive array control unit that controls the directivity of reception signals received by the plurality of reception antenna elements 26 by adaptive array processing. The reception signal strength determination unit 50 determines whether the reception signals received by the plurality of reception antenna elements 26 have a predetermined quality, that is, whether the reception signal quality is sufficient. It functions as a part.

  The directivity control switching unit 60 first controls the directivity of the received signal by the PAA weight control unit 54, and controls the directivity of the received signal by the PAA weight control unit 54. When the determination by the reception signal strength determination unit 50 is negative, the AAA weight control unit 56 performs switching so as to control the directivity of the reception signal. In other words, the directivity of the received signal is controlled by the PAA weight control unit 54, and if it is determined that the received signal cannot be correctly decoded, the AAA weight control unit 56 Switch to control directivity.

  The AAA weight control unit 56 preferably determines an initial value of a weight to be given to each reception signal received by the plurality of reception antenna elements 26 based on a control result by the PAA weight control unit 54. For example, the weight corresponding to the angle at which the received signal strength detected by the received signal strength determining unit 50 in the phased array control by the PAA weight control unit 54 is the highest is received by the plurality of receiving antenna elements 26 in adaptive array control. The initial value of the weight given to each received signal to be received is determined.

  FIG. 4 is a flowchart for explaining information communication control with the wireless tag 14 by the DSP 16 of the wireless tag communication device 12, and is repeatedly executed at a predetermined cycle.

First, in step (hereinafter, step is omitted) SA1, a command bit string corresponding to a transmission signal to the wireless tag 14 is generated, encoded by the FSK method, modulated by the AM method, and then transmitted signal D. / via the a converter 18 and up converter 22 is transmitted to the wireless tag 14 as interrogating wave F _c from the transmitting antenna element 24. Then, at SA2, the wireless tag 14 is returned from the response wave F _r are received by the plurality of receiving antenna elements 26, the down converter 28 and the received signal in response to the transmitted interrogating wave F _c at SA1 The data is stored in the memory unit 32 via the A / D conversion unit 30. Next, after the PAA control shown in FIG. 5 is executed, it is determined in SA3 whether or not the wireless tag 14 to be communicated has been detected. If the determination at SA3 is negative, the routine is terminated with an error because there is no wireless tag 14 to be communicated, but if the determination at SA3 is affirmative, the AAA control shown in FIG. After being executed, this routine is terminated.

FIG. 5 is a flowchart for explaining PAA (Phased Array Antenna) control which is a part of the RFID communication control of FIG. In this control, first, in SB1, the PAA weight set value θ _PAA is set to an initial value of −60 [°]. Next, in SB2, received signals corresponding to the plurality of receiving antenna elements 26 stored in SA2 of FIG. Next, in SB3, a plurality of received signals read in SB2 are multiplied by a PAA weight, and a combined output Y from the received signal combining unit 42 is calculated. Next, in SB4, the combined output Y from the received signal combining unit 42 is demodulated by the AM demodulation unit 44. Next, in SB5, it is determined whether or not the response wave (reflected wave) component from the wireless tag 14 included in the combined output Y calculated in SB3 is the maximum. If the determination in SB5 is positive, in SB6, after the wireless angle indicating the direction of the tag 14 θ _{REF_MAX} is a theta _PAA, SB7 but the following process is executed, the judgment of SB5 is negative In SB7, 30 [°] is added to the set value θ _PAA of the PAA weight in SB7, and then the demodulated signal output from the AM demodulator 44 is decoded by the FSK decoder 46 in SB8. . Next, in SB9, the response bit string interpretation unit 48 determines whether or not the decoding in SB8 has been performed normally. If the determination at SB9 is affirmed, this routine is terminated accordingly. If the determination at SB9 is negative, the PAA weight set value θ _PAA is larger than 60 ° in SB10. It is determined whether or not. When the determination at SB10 is negative, the processes after SB2 are executed again. However, when the determination at SB10 is affirmative, the control returns to the control shown in FIG. In the above control, SB5 and SB6 are the operations of the received signal strength determination unit 50, SB9 is the operation of the directivity control switching unit 60, and SB1, SB7, and SB10 are the operations of the PAA weight control unit 54, respectively. Correspond.

FIG. 6 is a flowchart for explaining AAA (Adaptive Array Antenna) control which is a part of the RFID communication control of FIG. In this control, first, in SC1, the set value of AAA weight is set to a value corresponding to the angle θ _{REF_MAX} defined in SB6 of FIG. Next, in SC2, received signals corresponding to the plurality of receiving antenna elements 26 stored in SA2 of FIG. Next, in SC3, the plurality of received signals read out in SC2 are multiplied by AAA weights, and the combined output Y from the received signal combining unit 42 is calculated. Next, in SC4, the combined output Y from the received signal combining unit 42 is demodulated by the AM demodulation unit 44. Next, in SC5, an error signal that is the difference between the reference signal output from the reference signal generator 58 and the combined output Y from the received signal combiner 42 calculated in SC3 is obtained. Next, at SC6, the error signal calculated at SC5 is substituted into a predetermined recurrence formula (for example, RLS algorithm) for weight update, and the weight value W ₀ multiplied by the weight multiplier 40, W ₁ and W ₋₁ are updated. Next, in SC7, it is determined whether or not the weight calculated in SC6 has converged. When the determination of SC7 is negative, the processing after SC2 is executed again. However, when the determination of SC7 is positive, the demodulated signal output from the AM demodulator 44 is received at SC8. After being decoded by the FSK decoding unit 46, the control is returned to the control shown in FIG. In the above control, SC1 and SC5 to SC7 correspond to the operation of the AAA weight control unit 56.

  Thus, according to the present embodiment, the PAA weight control unit 54 (SB1, SB7, and SB10) that controls the directivity of the received signals received by the plurality of receiving antenna elements 26 by phased array processing, AAA weight control unit 56 (SC1 and SC5 to SC7) for controlling the directivity of reception signals received by the plurality of reception antenna elements 26 by adaptive array processing, and reception signals received by the plurality of reception antenna elements 26 The reception signal strength determination unit 50 (SB5 and SB6) functioning as a reception quality determination unit that determines whether or not the signal has a predetermined quality, and first, the directivity of the reception signal is controlled by the PAA weight control unit 54. When the determination of the reception quality determination unit is negative, the AAA weight control unit 56 Since the directivity control switching unit 60 (SB9) that switches so as to control the directivity of the received signal is included, it is possible to avoid unnecessary calculations by performing adaptive array processing only when necessary. Signal processing time can be shortened. That is, it is possible to provide the wireless reception device 62 that can perform directivity control as quickly as possible.

  Further, the AAA weight control unit 56 determines the initial value of the weight given to each of the received signals received by the plurality of receiving antenna elements 26 based on the control result by the PAA weight control unit 54. The time required for array processing can be further reduced.

  In addition, the reception quality determination unit is a reception signal strength determination unit 50 that determines whether or not the signal strength of the reception signal is equal to or greater than a predetermined value, and the determination of the reception signal strength determination unit 50 is negative Since the determination is negative, the quality of the received signal can be determined in a practical manner.

  In addition, since the communication target is the wireless tag 14 that can return the signal in response to a predetermined transmission signal, the wireless tag communication device 12 that communicates information with the wireless tag 14 is as much as possible. It is possible to provide the wireless reception device 62 that can perform directivity control promptly.

  Next, another preferred embodiment of the present invention will be described in detail with reference to the drawings. In addition, regarding the drawings used for the following description, portions common to the above-described embodiments are denoted by the same reference numerals and description thereof is omitted.

  FIG. 7 is a diagram illustrating a configuration of a wireless tag communication device 80 in which a wireless reception device 82 according to another embodiment of the present invention is incorporated. As shown in FIG. 7, the DSP 16 of the RFID tag communication device 80 is an interference wave determination unit that determines whether or not an interference wave component is included in the combined signal output from the reception signal combining unit 42. An FFT (Fast Fourier Transform) unit 84 is functionally provided, and the directivity control switching unit 60 determines which one of the PAA weight control unit 54 and the AAA weight control unit 56 based on the determination of the FFT unit 84. The weights supplied to the plurality of weight multiplying units 40 are controlled by either of them. That is, the FFT unit 84 functions as a reception quality determination unit that determines whether or not the quality of reception signals received by the plurality of reception antenna elements 26 is sufficient.

FIG. 8 shows experimental data obtained by the inventor through simulation. When the determination of the FFT unit 84 is negative, that is, when the interference signal component is not included in the synthesized signal output from the received signal synthesizing unit 42. The relationship between the frequency and the signal strength is shown. As shown in FIG. 8, if the combined signal does not contain the interference wave component, the corresponding frequency components in the response wave (reflected wave) F _r from the carrier and the wireless tag 14 of the interrogating wave F _c Only the peak appears. On the other hand, FIG. 9 shows the relationship between the frequency and the signal strength when the determination of the FFT unit 84 is affirmed, that is, when the interference signal component is included in the combined signal output from the received signal combining unit 42. Yes. As shown in FIG. 9, when an interference wave component is included in the synthesized signal, a peak also appears in the frequency component unrelated to the carrier wave of the interrogation wave F _c and the response wave F _r from the wireless tag 14.

  The directivity control switching unit 60 first controls the directivity of the received signal by the PAA weight control unit 54, and controls the directivity of the received signal by the PAA weight control unit 54. When the determination of the FFT unit 84 is affirmed, the AAA weight control unit 56 performs switching so as to control the directivity of the received signal. In other words, the directivity of the received signal is controlled by the PAA weight control unit 54, and if it is determined that the received signal cannot be correctly decoded, the AAA weight control unit 56 Switch to control directivity.

  FIG. 10 is a flowchart for explaining PAA control in information communication control with the wireless tag 14 by the DSP 16 of the wireless tag communication device 80, and corresponds to the control of FIG. 5 described above. Note that information communication control and AAA control with the wireless tag 14 by the DSP 16 of the wireless tag communication device 80 are executed according to the flowcharts of FIGS. Is omitted. Further, in the PAA control shown in FIG. 10, the steps common to the control of FIG. 5 described above are denoted by the same reference numerals and the description thereof is omitted.

  In the control of FIG. 10, following the process of SB3 described above, in SB11, the synthesized output Y output from the received signal synthesizer 42 is subjected to FFT processing. Next, in SB12, it is determined whether or not an interference wave component is detected in the FFT processing in SB11. When the determination at SB12 is negative, the above-described processing after SB4 is executed. When the determination at SB12 is affirmative, the control is returned to the control shown in FIG. Processing is executed. In the above control, SB11 and SB12 correspond to the operation of the FFT unit 84, and SB12 corresponds to the operation of the directivity control switching unit 60, respectively.

  Thus, according to the present embodiment, the reception quality determination unit is the FFT unit 84 (SB11 and SB12) that determines whether or not the received signal includes an interference wave. When affirmative, the determination is denied, so the quality of the received signal can be determined in a practical manner.

FIG. 11 is a diagram illustrating a configuration of a wireless tag communication device 86 in which a wireless reception device 88 according to still another embodiment of the present invention is incorporated. As shown in FIG. 11, the RFID tag communication device 86 stores the transmission signal modulated by the AM modulation unit 38 and causes the DSP 16 to output the transmission signal in response to a command from the DSP 16. A memory unit 90 which is a storage device and a plurality (three in FIG. 11) of transmission signal D / A conversion units 18a, 18b and 18c (in FIG. 11) which convert the directivity-controlled transmission signals supplied from the DSP 16 into analog signals. Hereinafter, when not particularly distinguished, they are simply referred to as a transmission signal D / A conversion unit 18), and the frequency of each transmission signal converted into an analog signal by the transmission signal D / A conversion unit 18 is referred to as the frequency conversion signal output unit. A plurality (three in FIG. 11) of up-converters 22a, 22b, and 22c (hereinafter, particularly, the frequency conversion signal output from 20 is increased by the frequency of the frequency conversion signal). Simply referred to as the up-converter 22) if it does not separate, three Multiple (11 for transmission toward the wireless tag 14 a transmission signal is up-converted respectively by their up-converter 22 as interrogating wave F _c ) Transmitting antenna elements 24a, 24b, 24c (hereinafter simply referred to as transmitting antenna element 24 unless otherwise distinguished). In addition, the DSP 16 of the RFID tag communication device 86 includes a plurality (three in FIG. 11) of transmission side weight multiplication units 94a and 94b that multiply the transmission signal by the PAA weight or AAA weight calculated by the weight control unit 52. , 94c (hereinafter simply referred to as a transmission side weight multiplication unit 94 unless otherwise specified). That is, the wireless tag communication device 86 of this embodiment has a configuration capable of performing directivity control for both transmission and reception.

  FIG. 12 is a flowchart for explaining information communication control with the wireless tag 14 by the DSP 16 of the wireless tag communication device 86, and corresponds to the control of FIG. 4 described above. In the RFID communication control shown in FIG. 12, the steps common to the control of FIG. 4 described above are denoted by the same reference numerals and the description thereof is omitted.

  In the control of FIG. 12, following the PAA control shown in FIG. 5 described above, it is determined in SA4 whether or not the wireless tag 14 that is a communication target has been detected. When the determination at SA4 is negative, the second PAA control shown in FIG. 13 is executed. When the determination at SA4 is positive, the AAA control shown in FIG. 6 is executed. Thereafter, in SA5, the response bit string interpretation unit 48 determines whether normal decoding has been performed. If the determination at SA5 is affirmative, the routine is terminated accordingly. If the determination at SA5 is negative, the second PAA control shown in FIG. 13 is executed and then at SA6. Then, it is determined whether or not the wireless tag 14 to be communicated has been detected. If the determination at SA6 is negative, the routine is terminated with an error because there is no wireless tag 14 to be communicated, but if the determination at SA6 is affirmative, the AAA shown in FIG. After the control is executed, this routine is terminated.

  FIG. 13 is a flowchart for explaining the second PAA control which is a part of the RFID communication control of FIG. In the second PAA control shown in FIG. 13, the steps common to the control of FIG. 5 described above are denoted by the same reference numerals and the description thereof is omitted.

In the control of FIG. 13, following the processing of SB1 described above, in SB11, the transmission signal read from the memory unit 90 is multiplied by the PAA weight calculated by the weight control unit 52, and the plurality of transmission signals The interrogation wave _Fc is transmitted toward the wireless tag 14 from the plurality of transmission antenna elements 20 via the D / A converter 18 and the upconverter 20. Then, in SB12, received by the receiving antenna element 26 the radio tag 14 in response wave F _r sent back from the said plurality in accordance with the interrogating wave F _c transmitted in SB11, the plurality of down-converters 28 and After being stored in the memory unit 32 via the reception signal A / D conversion unit 30, the above-described processing from SB2 is executed.

  In this way, the wireless tag communication device 86 first performs PAA processing and AAA processing only on the received signal, with the directivity of the transmission signal transmitted by the plurality of transmission antenna elements being initially set, and the wireless tag communication device 86 performs the wireless communication. When the reply signal returned from the tag 14 is not properly decoded, the transmission directivity and reception directivity are controlled by the PAA weight control unit 54, and the determination of the reception quality determination unit is denied. Is switched so as to control the transmission directivity and the reception directivity by the AAA weight control unit 56, so that suitable information communication with the wireless tag 14 can be performed.

  FIG. 14 is a diagram for explaining the configuration of a wireless tag communication device 96 in which a wireless reception device 98 according to still another embodiment of the present invention is incorporated. As shown in FIG. 14, the DSP 16 of the RFID tag communication device 96 has a functional error determination unit 100 that determines whether or not the decoding result of the received signal by the response bit string interpretation unit 48 is an error. The directivity control switching unit 60 is provided to the plurality of weight multiplication units 40 by either one of the PAA weight control unit 54 and the AAA weight control unit 56 based on the determination of the error determination unit 100. Switch so that the supplied weight is controlled. That is, the error determination unit 100 functions as a reception quality determination unit that determines whether or not the quality of reception signals received by the plurality of reception antenna elements 26 is sufficient. In other words, the error determination unit 100 determines whether or not the decoding quality of the received signal by the response bit string interpretation unit 48 is within a predetermined range, and the decoding quality is outside the predetermined range. Is determined to be an error in the decoding result of the received signal.

  The directivity control switching unit 60 first controls the directivity of the received signal by the PAA weight control unit 54, and controls the directivity of the received signal by the PAA weight control unit 54. When the determination by the error determination unit 100 is affirmative, the AAA weight control unit 56 performs switching so as to control the directivity of the received signal. In other words, when it is determined that the received signal cannot be correctly decoded by controlling the directivity of the received signal by the PAA weight control unit 54, the directivity of the received signal is determined by the AAA weight control unit 56. Switch to control.

  As described above, according to this embodiment, the FSK decoding unit 46 that decodes the received signal is included, and the reception quality determination unit determines whether or not the decoding result of the received signal by the response bit string interpretation unit 48 is an error. If the determination of the error determination unit 100 is affirmative, the determination is negative, and therefore the quality of the received signal is determined in a practical manner. Can do.

  The preferred embodiments of the present invention have been described in detail with reference to the drawings. However, the present invention is not limited to these embodiments, and may be implemented in other modes.

  For example, in the above-described embodiment, before performing the PAA control, first, the directivity of the reception signals received by the plurality of reception antenna elements 26 is left at the initial setting (for example, omnidirectional state), and the PAA weight control unit 54 and the AAA weight control unit 56 do not operate so that the reception quality determination unit performs the determination. If the determination is negative, the PAA weight control unit 54 controls the directivity of the received signal. You may make it switch to. By doing so, the processing time can be further shortened when there is a high possibility that the wireless tag is relatively close.

  In the above-described embodiment, the reception quality determination unit that determines whether the quality of the reception signals received by the plurality of reception antenna elements 26 is sufficient is the reception signal strength determination unit 50 and the FFT unit 84. However, the present invention is not limited to this. For example, any two or all of them are included as the reception quality determination unit, and a plurality of error determination units 100 are included. The directivity control may be switched according to the determination result of the reception quality determination unit. Further, it may be determined whether or not the quality of the received signal is sufficient according to a mode different from the above-described embodiment, for example, whether or not the demodulation result by the AM demodulating unit 44 is an error. You may make the said determination by determining.

  In the above-described embodiment, the received signal strength determination unit 50, the weight control unit 52, the PAA weight control unit 54, the AAA weight control unit 56, the directivity control switching unit 60, and the like are functionally provided in the DSP 16. However, these may be provided as individual control devices. Also, it does not matter whether these controls are based on digital signal processing or analog signal processing.

  In the above-described embodiment, the RFID tag communication device 12 or the like includes the transmission antenna element 24 for transmitting the transmission signal and the reception antenna element 26 for receiving the return signal, respectively. However, the present invention is not limited to this, and may include a transmission / reception shared antenna element for transmitting the transmission signal and receiving the return signal. In this way, the configuration of the wireless tag communication device 12 and the like can be made as simple as possible.

  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.

It is a figure explaining the communication system with which the radio | wireless receiver of this invention is used suitably. It is a figure explaining the structure of the radio | wireless tag communication apparatus with which the radio | wireless receiver which is one Example of this invention was integrated. It is a figure explaining the structure of the wireless tag which is a communication object of the wireless tag communication apparatus of FIG. 4 is a flowchart for explaining information communication control between the wireless tag communication apparatus of FIG. 2 and the wireless tag of FIG. 3 by a DSP. 5 is a flowchart illustrating PAA control that is a part of RFID communication control in FIG. 4. It is a flowchart explaining AAA control which is a part of RFID communication control of FIG. It is a figure explaining the structure of the radio | wireless tag communication apparatus with which the radio | wireless receiver which is another Example of this invention was integrated. FIG. 8 is a diagram illustrating a relationship between a frequency and a signal intensity when an interference wave component is not included in a combined signal output from a received signal combining unit in the RFID tag communication apparatus of FIG. 7. It is a figure which shows the relationship between a frequency and signal strength in case the interference signal component is contained in the synthetic | combination signal output from a received signal synthetic | combination part in the RFID tag communication apparatus of FIG. 8 is a flowchart illustrating PAA control in information communication control with the wireless tag of FIG. 3 by a DSP of the wireless tag communication device of FIG. 7. It is a figure explaining the structure of the radio | wireless tag communication apparatus incorporating the radio | wireless receiving apparatus which is another Example of this invention. 12 is a flowchart for explaining information communication control between the wireless tag communication apparatus of FIG. 11 and the wireless tag of FIG. 3 by a DSP. 13 is a flowchart illustrating second PAA control that is a part of the RFID communication control of FIG. 12. It is a figure explaining the structure of the radio | wireless tag communication apparatus incorporating the radio | wireless receiving apparatus which is another Example of this invention.

Explanation of symbols

14: Wireless tag (communication target)
26: reception antenna element 46: FSK decoding unit 50: received signal strength determination unit (reception quality determination unit)
54: PAA weight control unit (phased array control unit)
56: AAA weight control unit (adaptive array control unit)
60: Directivity control switching units 62, 82, 88, 98: Radio reception device 84: FFT unit (interference wave determination unit, reception quality determination unit)
100: Error determination unit (reception quality determination unit)

Claims (7)

A wireless reception device including a plurality of reception antenna elements for receiving a signal transmitted from a predetermined communication target,
A phased array controller that controls the directivity of received signals received by the plurality of receiving antenna elements by phased array processing;
An adaptive array control unit that controls the directivity of reception signals received by the plurality of reception antenna elements by adaptive array processing;
A reception quality determination unit that determines whether or not reception signals received by the plurality of reception antenna elements have a predetermined quality;
The directivity of the received signal is controlled by the phased array control unit, and when the determination of the reception quality determination unit is negative, the adaptive array control unit is switched to control the directivity of the received signal. And a radio control switching unit.   2. The radio reception apparatus according to claim 1, wherein the adaptive array control unit determines an initial value of a weight to be given to each reception signal received by the plurality of reception antenna elements based on a control result by the phased array control unit.   The directivity control switching unit first sets the directivity of reception signals received by the plurality of reception antenna elements as an initial setting, and when the determination of the reception quality determination unit is negative, the phased array control unit The radio receiving apparatus according to claim 1 or 2, wherein switching is performed so as to control directivity of the received signal.   The reception quality determination unit is a reception signal strength determination unit that determines whether or not the signal strength of the reception signal is greater than or equal to a predetermined value, and when the determination of the reception signal strength determination unit is negative, The radio reception apparatus according to claim 1, wherein the determination is negative.   The reception quality determination unit is an interference wave determination unit that determines whether or not an interference wave is included in the received signal. When the determination of the interference wave determination unit is affirmed, the determination is negative The wireless receiver according to any one of claims 1 to 3.   A decoding unit that decodes the received signal, wherein the reception quality determination unit is an error determination unit that determines whether or not the decoding quality of the reception signal by the decoding unit is within a predetermined range, and the error determination unit The wireless reception device according to any one of claims 1 to 3, wherein the determination is negative when the determination is negative.   The wireless receiving device according to claim 1, wherein the communication target is a wireless tag capable of returning the signal in response to a predetermined transmission signal.

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