JP4803017B2 - COMMUNICATION PROCESSING DEVICE, COMMUNICATION PROCESSING METHOD, AND PROGRAM - Google Patents

Description

  The present invention relates to a communication processing device that performs communication with an RFID tag.

  As a communication processing device that communicates with a conventional RFID tag, such as a reader / writer, a threshold is set for the number of packet errors due to packet collisions or the packet discard rate, and multiple reader / writers use until the threshold is exceeded. There has been one in which frequency switching is not performed (for example, see Patent Document 1).

  On the other hand, the law concerning radio waves in Japan and the like sets an upper limit on the period during which the transmission state of the communication processing device is continued, that is, the transmission period, in order to prevent the occupation of the channel by the communication processing device for one RFID tag, Furthermore, it may be defined that the transmission stop state must be continued for a predetermined period after the transmission period is stopped. For example, in a UHF band RFID tag communication processing apparatus, the transmission period is set to a maximum of 4 seconds, and the transmission is stopped for a minimum of 50 ms (milliseconds) in the transmission stop period after the transmission is stopped. The state must be continued.

In addition, the communication processing apparatus for the RFID tag performs processing for detecting an empty channel called LBT (Listen Before Talk) processing before performing communication with the tag. LBT processing refers to whether or not a communication processing device such as another reader / writer is transmitting radio waves in a surrounding frequency band that can be used by the communication processing device before the start of radio wave transmission. Checking process. By this LBT process, a channel through which no radio wave is transmitted, that is, a so-called empty channel, is designated as a communication channel with the tag. In Japan, a frequency band that can be used by a communication processing apparatus such as a UHF band reader / writer is between 952.2 MHz and 953.8 MHz, and each channel is a total of nine channels of 200 kHz steps.
Japanese Unexamined Patent Publication No. 2006-261986 (first page, FIG. 1 etc.)

  However, the conventional communication processing apparatus has a problem that it cannot efficiently communicate with the RFID tag.

  Specifically, in a conventional communication processing device, after detecting an empty channel by LBT processing, communication is started using this empty channel. In response to a command transmitted to a tag immediately after the start of communication. When there is no response from the tag within a predetermined period, it is determined that there is no tag in the communication area, communication is stopped, and the transmission period ends. However, in such a situation, an empty channel that can be detected by the LBT process is immediately released, and it is necessary to wait at least a predetermined transmission stop period until the next communication start. Could not perform efficient communication. To give a specific example, when an RFID tag is attached to a package carried on a high-speed conveyor, immediately after the reader / writer stops communication, the package with the RFID tag attached enters the communication area. There was a problem that the tag could not be read because the transmission was suspended.

  On the other hand, in order to secure a wide communication area or eliminate blind spots in the communication area due to antenna directivity, etc., a communication processing apparatus that performs communication with the RFID tag by sequentially switching a plurality of antennas When it is determined that there is no communicable RFID tag in the communication area of the antenna, it is not appropriate for efficient communication to continue the preset transmission period of the antenna. In such a situation, the person who immediately stops the transmission period of the antenna, switches to another antenna after the predetermined transmission suspension period, and communicates with the tag in the communication area of the other antenna. This is because it is considered efficient from the viewpoint of communication of the entire communication processing apparatus.

  Similarly, in a conventional communication processing apparatus that performs communication with an RFID tag by sequentially switching a plurality of antennas, it is not efficient to perform LBT processing for one antenna until an empty channel is set. . In such a situation, it is considered more efficient from the viewpoint of communication of the entire communication processing apparatus to stop LBT processing by the antenna immediately, switch to another antenna, and perform LBT processing for the other antenna. Because it is.

  On the other hand, if one antenna is used, if LBT processing is performed only for a preset time, if an empty channel is not detected, communication processing cannot be performed, or it is necessary to change the time and perform LBT processing again. There is a waste of time and it becomes inefficient.

  The communication processing device of the present invention is a communication processing device that performs communication with an RFID tag, a transmission unit that transmits a command to the RFID tag, a reception unit that receives information transmitted from the RFID tag, An output unit that outputs information received by the reception unit, an absence detection unit that detects the absence of an RFID tag according to the reception status of the reception unit when the transmission unit transmits the command, and the absence detection The communication processing apparatus includes a retransmission instruction unit that instructs the transmission unit to retransmit the command when the unit detects the absence of the RFID tag within one transmission period. Note that the communication processing apparatus of the present invention may use a transmission antenna and a reception antenna that are provided separately, or use an antenna that can perform both transmission and reception. There may be.

  With such a configuration, the detected empty channel can be used efficiently, and efficient communication with the RFID tag becomes possible.

  The communication processing device of the present invention is a communication processing device that performs communication with an RFID tag, and is a transmission unit that is connected to one or more transmission antennas and transmits a command to the RFID tag using the transmission antenna. A receiving unit that is connected to one or more receiving antennas paired with the one or more transmitting antennas and receives information transmitted from the RFID tag using the receiving antenna, and information received by the receiving unit Output unit, and when the transmission unit transmits the command using one of the one or more transmission antennas, one reception antenna corresponding to the one transmission antenna is used. According to the reception status of the reception unit, it is determined whether or not the number of pairs of the absence detection unit that detects the absence of the RFID tag and the transmission antenna and the reception antenna is two or more. The antenna number determination unit and the antenna number determination unit determine that the number of pairs of the transmission antenna and the reception antenna is 2 or more, and the absence detection unit detects the RFID tag within one transmission period. A switching instruction unit that outputs an instruction to switch the transmission antenna and the reception antenna to the transmission unit and the reception unit, and the antenna number determination unit includes a pair of the transmission antenna and the reception antenna. When the absence detection unit detects the absence of an RFID tag within one transmission period, the retransmission instruction that instructs the transmission unit to retransmit the command. A communication processing apparatus. Note that the communication processing device of the present invention may use one or more separately provided transmission antennas and reception antennas, or one antenna that can perform both transmission and reception. It may be used above.

  With this configuration, depending on the number of pairs of transmission antennas and reception antennas, whether to retransmit a command when an RFID tag is not detected during communication using each transmission antenna and reception antenna is changed. Thus, efficient communication is possible.

  In the communication processing device according to the present invention, in the communication processing device, the retransmission instruction unit repeats the retransmission instruction until a predetermined number of times is set until an RFID tag is detected. It is.

  With this configuration, it is possible to efficiently communicate with the RFID tag.

  In the communication processing device of the present invention, in the communication processing device, the retransmission instruction unit repeats the retransmission instruction until a predetermined time elapses until an RFID tag is detected. Device.

  With this configuration, it is possible to efficiently communicate with the RFID tag.

  The communication processing apparatus of the present invention is a communication processing apparatus that communicates with an RFID tag using one of a plurality of channels. The communication processing apparatus is connected to one or more transmission antennas and uses the transmission antennas. A transmission unit that transmits a command to the RFID tag, and a reception unit that is connected to one or more reception antennas paired with the one or more transmission antennas and receives information using the reception antenna; Of the information received by the receiving unit, an output unit that outputs information transmitted from the RFID tag, and information received using one receiving antenna of the one or more receiving antennas, Whether the number of pairs of the empty channel detection unit for detecting an empty channel used as a channel for performing communication and the transmission antenna and the reception antenna is two or more The number of antennas determining unit for determining whether the number of pairs of the transmitting antenna and the receiving antenna is 2 or more. If the empty channel detection unit cannot detect an empty channel, the reception unit is instructed to switch the reception antenna to detect an empty channel, and the antenna number determination unit receives the transmission antenna and the reception antenna. When it is determined that the number of pairs with the antenna is not 2 or more, and the empty channel detection unit cannot detect an empty channel, the communication processing device repeats the detection of the empty channel. Note that the communication processing device of the present invention may use one or more separately provided transmission antennas and reception antennas, or one antenna that can perform both transmission and reception. It may be used above.

  With this configuration, according to the number of pairs of the transmission antenna and the reception antenna, whether or not to perform the empty channel processing when an empty channel is not detected when an empty channel is detected using each transmission antenna and reception antenna. By changing the above, efficient communication becomes possible.

  The communication processing device according to the present invention is the communication processing device according to the communication processing device, wherein the antenna number determination unit repeats the detection of the empty channel until a predetermined number of times set in advance.

  With this configuration, it is possible to efficiently communicate with the RFID tag.

  In the communication processing apparatus of the present invention, in the communication processing apparatus, the antenna number determination unit repeats the detection of the empty channel until a predetermined time elapses until an empty channel is detected. It is a communication processing device that performs up to.

  With this configuration, it is possible to efficiently communicate with the RFID tag.

  According to the communication processing apparatus and the like according to the present invention, it is possible to efficiently communicate with the RFID tag.

  Hereinafter, embodiments of a communication processing apparatus and the like will be described with reference to the drawings. In addition, since the component which attached | subjected the same code | symbol in embodiment performs the same operation | movement, description may be abbreviate | omitted again.

(Embodiment)
FIG. 1 is a block diagram of a communication processing apparatus according to the present embodiment. The communication processing apparatus according to the present embodiment is, for example, a reader / writer that communicates with an RFID tag such as a UHF band.

  The communication processing apparatus 1 includes a transmission unit 101, a transmission instruction reception unit 102, a reception unit 103, an output unit 104, an absence detection unit 105, a retransmission instruction unit 106, an antenna number determination unit 107, a switching instruction unit 108, and an empty channel detection unit 109. A communication control unit 110, one or more transmission antennas 111, and one or more reception antennas 112. In the figure, for convenience, the case where there are three transmission antennas 111 and three reception antennas 112 is shown, but the number of each may be one or more. Note that the communication processing apparatus 1 may include the transmission antenna 111 and the reception antenna 112, or may include an external transmission antenna and reception antenna without using the transmission antenna or the reception antenna. .

  The transmission unit 101 transmits a command to the RFID tag. The command transmitted by the transmission unit 101 may be any command. Further, the command described here includes information usable as a command as a result. This command is, for example, a read command for reading information on the RFID tag, a write command for writing information on the RFID tag, or the like. The command transmitted by the transmission unit 101 may be included in the transmission instruction received by the transmission instruction reception unit 102, or a command stored in advance in a memory (not shown) or the like is read according to the transmission instruction. Any command acquisition route may be used. The transmission unit 101 is connected to one or more transmission antennas 111, and uses the transmission antenna 111 to transmit a command by radio waves to the RFID tag. Normally, any one of the transmission antennas 111 is selected, or each transmission antenna 111 is sequentially switched one by one, and a command is transmitted from the selected transmission antenna 111. The transmission unit 101 transmits a command using, for example, the transmission antenna 111 specified by an instruction output from the switching instruction unit 108, the communication control unit 110, or the like. The transmission unit 101 normally transmits a command using the empty channel detected by the empty channel detection unit 109. Further, the transmission unit 101 retransmits a command in response to a retransmission instruction output from a retransmission instruction unit 106 described later. The transmission unit 101 is connected to one or more transmission antennas 111 via an interface such as one or more transmission ports (not shown), for example. The transmission unit 101 normally transmits a command in response to a transmission instruction received by a transmission instruction reception unit 102 described later. However, the command may be transmitted every predetermined period that is constant or indefinite. The transmission unit 101 can be realized by a wireless transmission unit or the like. Moreover, you may implement | achieve with a broadcast means.

  The transmission instruction reception unit 102 receives a transmission instruction for the transmission unit 101. For example, the transmission instruction receiving unit 102 may receive a transmission instruction transmitted from a device external to the communication processing apparatus 1 such as a computer via a communication line or the like, or a transmission recorded in a recording medium or the like The instruction may be read out. The transmission instruction received by the transmission instruction reception unit 102 may or may not include an instruction including a command transmitted by the transmission unit 101. Moreover, the command which the transmission part 101 transmits may be specified. Further, the transmission instruction receiving unit 102 may receive a transmission instruction input by an input unit such as a numeric keypad, a keyboard, a mouse, or a menu screen. The transmission instruction receiving unit 102 is a device for reading information from a communication device driver, a device driver for input means such as a numeric keypad and a keyboard, menu screen control software, a memory card reader, a recording medium such as a CD drive, and the like. It can be realized with a driver or the like.

  The receiving unit 103 receives information transmitted from the RFID tag. In addition, the receiving unit 103 is a frequency band used for communication with an RFID tag, which is transmitted by a device such as another communication processing device, for the empty channel detection processing such as LBT processing described in the related art. Information, in other words, radio waves. The receiving unit 103 is connected to one or more receiving antennas 112 and uses the receiving antennas 112 to receive information output from the RFID tag. The receiving unit 103 normally selects any one of the reception antennas 112, or sequentially switches and selects each reception antenna 112 one by one, and receives information using the selected reception antenna 112. One or more receiving antennas connected to the receiving unit 103 are one or more antennas paired with one or more transmitting antennas 111. For example, the reception unit 103 receives information using the reception antenna 112 specified by an instruction output from the switching instruction unit 108, the communication control unit 110, or the like. When receiving the information transmitted from the RFID tag, the receiving unit 103 normally receives information using the empty channel detected by the empty channel detecting unit 109. The receiving unit 103 is connected to one or more receiving antennas 112 via an interface such as one or more receiving ports (not shown), for example. The receiving unit 103 can be realized by a wireless receiving unit or the like.

  The output unit 104 outputs information received by the receiving unit 103. Specifically, the information transmitted from the RFID tag among the information received by the receiving unit 103 is output. The output unit 104 may output the entire information received by the receiving unit 103 or may output a part of the information. For example, when header information or the like is added to the information received by the receiving unit 103, information including the header information or the like may be output, or information from which the header information is removed may be output. The output described here is usually transmission via a communication line or the like to a device or the like outside the communication processing apparatus 1 such as a computer. However, it may be displayed on a display or stored in a recording medium. The output unit 104 can be realized by driver software of an output device such as a communication device, or driver software of the output device and an output device.

  The absence detection unit 105 detects the absence of the RFID tag in the communication area according to the reception status of the reception unit 103 when the transmission unit 101 transmits a command. Specifically, the absence detection unit 105, when the transmission unit transmits a command using one transmission antenna 111, the reception unit 103 using one reception antenna 112 corresponding to the one transmission antenna 111. The absence of the RFID tag in the communication area of one transmission antenna 111 and reception antenna is detected according to the reception status. The reception status described here refers to whether or not there is any response from one or more RFID tags, for example, transmission of information from one or more RFID tags, or detection of collision (collision) in information transmitted from RFID tags. That is. Normally, when the receiving unit 103 receives information from one or more RFID tags within a predetermined period of time that is constant or indefinite after the transmitting unit 101 transmits a command, the receiving unit 103 determines that the RFID tag exists and receives the information. If the unit 103 does not receive, it is determined that the RFID tag is absent. The absence detection unit 105 can usually be realized by an MPU, a memory, or the like. Instead of detecting the absence of the RFID tag, the absence detection unit 105 may detect the presence of the RFID tag, and may determine that the RFID tag is absent when the presence cannot be detected. . The processing procedure of the absence detection unit 105 is usually realized by software, and the software is recorded in a recording medium such as a ROM. However, it may be realized by hardware (dedicated circuit).

  When the absence detection unit 105 detects the absence of the RFID tag, the retransmission instruction unit 106 instructs the transmission unit 101 to retransmit the command within one transmission period. In particular, when the communication processing apparatus 1 uses only a pair of the transmission antenna 111 and the reception antenna 112, it may be instructed to retransmit the command. The transmission period is a period from when the transmission unit 101 starts transmission until the transmission unit 101 stops transmission and the reception unit 103 stops reception. For example, the transmission period is a period during which command transmission by the transmission unit 101 is continuously performed one or more times. However, the transmission period may include a period during which information is received by the reception unit 103 and a period during which reception is waited for each command transmitted by the transmission unit 101. One transmission period is the same transmission period as the transmission period in which the absence detection unit 105 detects the absence of the RFID tag. One transmission period may be considered as a period from the start of command transmission using an empty channel until the channel is surrendered. One transmission period is a transmission stop period for passing a channel used for communication by the transmission unit 101 and the reception unit 103 after the transmission unit 101 starts transmission, for example, 50 ms in the UHF band, It is a period that does not sandwich. That is, when the absence detection unit 105 detects the absence of the RFID tag, the communication processing apparatus 1 retransmits the command from the transmission unit 101 without entering the transmission stop period. . For example, in the case of an RFID tag in the UHF band, the transmission period must be set to a maximum of 4 seconds. If the transmission period exceeds 4 seconds from the start of transmission, the retransmission instruction unit 106 issues an instruction to retransmit the command. Do not send. The retransmission instruction unit 106 may repeat the retransmission instruction until a predetermined number of times is set in advance until the RFID tag is detected. Further, the retransmission instruction unit 106 may repeat the retransmission instruction until a predetermined time elapses until an RFID tag is detected. That is, the retransmission process may be repeated until a so-called timeout occurs. The predetermined number of times and the predetermined time may be constant or indefinite. The information for setting the predetermined number of times and the predetermined time may be stored in advance in a memory (not shown), for example. The retransmission instruction unit 106 can be usually realized by an MPU, a memory, or the like. The processing procedure of the absence detection unit 105 is usually realized by software, and the software is recorded in a recording medium such as a ROM. However, it may be realized by hardware (dedicated circuit).

  The antenna number determination unit 107 determines whether the number of pairs of transmission antennas and reception antennas is two or more. Any number of antennas may be determined by the antenna number determination unit 107. For example, the number of antennas connected to the ports to which the transmitting antenna 111 and the receiving antenna 112 of the transmitting unit 101 and the receiving unit 103 are connected is detected using signals transmitted from these ports and the like. It may be determined from the number of antennas that the number of pairs of transmission antennas and reception antennas is two or more. In addition, information indicating the number of antennas designated by the user or the like is stored in a memory or the like (not shown) in advance, and the information stored in the memory or the like is read by the antenna number determination unit 107 and transmitted to the transmission antenna. It may be determined whether the number of pairs with the receiving antenna is 2 or more. Note that the information indicating the number of antennas may be information that can determine whether the number of antennas is two or more as a result, and may be information on the number of transmission antennas 111 and reception antennas 112. It may be information indicating that the number of pairs of transmission antennas and reception antennas is two or more. In addition, normally, since the transmission antenna and the reception antenna are paired, it may be determined whether either the number of transmission antennas or the number of reception antennas is two or more. Further, in the present embodiment, the information indicating the number of antennas is information used for selecting a process to be executed depending on whether the number of antennas is 2 or more. May be information instructing selection of a process to be selected depending on the number of antennas. As a result, the determination performed by the antenna number determination unit 107 may be a determination indicating whether or not the number of pairs of transmission antennas and reception antennas is two or more and a determination indicating the same result. It is not necessary to obtain the actual number of antennas and make a determination based on the number of antennas. For example, information that the number of pairs of transmission antennas and reception antennas is two or more and information that the number of pairs of transmission antennas and reception antennas is not two or more are prepared in advance. When the antenna number determination unit 107 receives information that the number of pairs of antennas and receiving antennas is 2 or more, the determination result that the number of antennas is 2 or more is output, and the pair of transmitting antennas and receiving antennas is output. When the antenna number determination unit 107 receives information that the number of antennas is not 2 or more, a determination result that the number of antennas is not 2 or more may be output. The communication processing apparatus 1 performs the first process when the determination result of the antenna number determination unit 107 is not two or more, and the determination result of the antenna number determination unit 107 indicates that the number of antennas is two. In the case of the above, when the second process is performed, the number of antennas determination unit 107 determines whether to perform the first process or the second process. As a result, it is considered to be the same as the case where the antenna number determination unit 107 determines whether or not the number of antennas is two or more. The antenna number determination unit 107 can be usually realized by an MPU, a memory, or the like. The processing procedure of the antenna number determination unit 107 is usually realized by software, and the software is recorded in a recording medium such as a ROM. However, it may be realized by hardware (dedicated circuit).

  The switching instruction unit 108 is a case where the antenna number determination unit 107 determines that the number of pairs of the transmission antenna 111 and the reception antenna 112 is two or more, and the absence detection unit 105 detects the absence of the RFID tag. In this case, an instruction to switch the transmission antenna 111 and the reception antenna 112 to the transmission unit 101 and the reception unit 103 is output. The transmission unit 101 and the reception unit 103 use the transmission antenna 111 and the reception antenna specified by the switching instruction to transmit a command and receive information from the RFID tag in the next transmission period. Further, the switching instruction unit 108 may output an instruction to cause the transmission unit 101 and the reception unit 103 to switch the transmission antenna 111 and the reception antenna 112 in accordance with an instruction from an empty channel detection unit 109 described later. The switching instruction unit 108 can usually be realized by an MPU, a memory, or the like. The processing procedure of the switching instruction unit 108 is usually realized by software, and the software is recorded on a recording medium such as a ROM. However, it may be realized by hardware (dedicated circuit).

  The vacant channel detection unit 109 detects an vacant channel to be used as a channel for communication with the RFID tag, using information received using one reception antenna 112 among the one or more reception antennas 112. For example, the vacant channel detection unit 109 detects the power of the frequency in the channel that can be used by the communication processing apparatus 1 and detects the channel determined to have no power as the vacant channel. Specifically, a frequency component of radio waves such as noise in a channel that can be used by the communication processing apparatus 1 received by the receiving unit 103 is extracted using fast Fourier transform or the like, and the frequency component of the extracted radio waves is a predetermined frequency component. If the level is not included, it is determined that this channel is an empty channel. This process is a known process called a so-called LBT process. For example, in the Japanese radio law, a noise level of -74 dBm must be detected for a minimum of 5 milliseconds during LBT processing. The vacant channel detection unit 109 is particularly used when the number of antennas determination unit 107 determines that the number of pairs of the transmission antenna 111 and the reception antenna 112 is 2 or more and the vacant channel cannot be detected. Then, the reception unit 103 is instructed to switch the reception antenna 112 to detect an empty channel. The vacant channel detection unit 109 may output this switching instruction directly to the receiving unit 103 or indirectly through the switching instruction unit 108 or the like. In addition, the empty channel detection unit 109 determines that the number of antennas determination unit 107 determines that the number of pairs of the transmission antenna 111 and the reception antenna 112 is not 2 or more, that is, 1 and is within a predetermined period. If no empty channel is detected, the detection of the empty channel is repeated. The empty channel detection unit 109 may repeat the detection of the empty channel until a predetermined number of times is preset until an empty channel is detected. Further, the empty channel detection unit 109 may repeat the detection of the empty channel until a predetermined time set in advance is reached until an empty channel is detected. For example, in UHF band RFID tags, it is stipulated by the Japanese communication law that LBT processing should be performed for 5 ms or longer. Keep it. The empty channel detection unit 109 can be usually realized by an MPU, a memory, or the like. The processing procedure of the empty channel detection unit 109 is usually realized by software, and the software is recorded on a recording medium such as a ROM. However, it may be realized by hardware (dedicated circuit).

  The communication control unit 110 controls the transmission unit 101, the reception unit 103, and the like to perform information reading processing, information writing processing, and the like on the RFID tag. The control performed by the communication control unit 110 is control for causing the communication processing apparatus 1 to perform processing such as reading and writing of information similar to a normal RFID tag reader / writer, and detailed description thereof is omitted here. . The communication control unit 110 can be usually realized by an MPU, a memory, or the like. The processing procedure of the communication control unit 110 is usually realized by software, and the software is recorded on a recording medium such as a ROM. However, it may be realized by hardware (dedicated circuit).

  The transmission antenna 111 converts the command transmitted by the transmission unit 101 into a radio wave and transmits the radio wave. In the present embodiment, it is assumed that one or more transmission antennas 111 can be connected to one transmission unit 101. The shape, structure, directivity, and the like of the transmission antenna 111 are not particularly limited as long as they can be used for communication with the RFID tag.

  The receiving antenna 112 receives a radio wave transmitted from an RFID tag or the like and transmits it to the receiving unit 103. In this embodiment, it is assumed that one or more receiving antennas 112 can be connected to one receiving unit 103. In the present embodiment, a case where reception antenna 112 is paired with one or more transmission antennas 111 will be described in particular. That is, here, it is assumed that the number of reception antennas 112 and the number of transmission antennas 111 are the same and correspond one-to-one. The shape, structure, directivity, and the like of the receiving antenna 112 are not particularly limited as long as they can be used for communication with the RFID tag. Needless to say, the pair of transmission antennas 111 and reception antennas 112 may be realized by a single transmission / reception antenna.

  Next, the operation of the communication processing apparatus 1 will be described using the flowchart of FIG. Here, first, a case where the transmission instruction reception unit 102 receives an instruction to transmit a desired command from an upper system such as an external computer will be described as an example.

  (Step S201) The communication processing apparatus 1 determines whether or not a predetermined time has elapsed since the end of the previous transmission period. For example, when the communication processing device 1 is a communication processing device for an RFID tag in the UHF band, the predetermined time is at least 50 ms or more based on radio law in Japan. , It is set to a time obtained by subtracting the time required for the LBT process. If the predetermined time has elapsed, the process proceeds to step S202. If not, the process returns to step S201. This process may be performed by any part of the communication processing device 1 such as the communication control unit 110.

  (Step S202) The antenna number determination unit 107 acquires the number M of antennas (M is an integer of 1 or more) of the transmission antenna 111 connected to the transmission unit 101. Normally, the number of reception antennas 112 connected to the reception unit 103 is also the same as the number M of antennas of the transmission antenna 111, so even if the number of reception antennas 112 connected to the reception unit 103 is acquired. good. The number-of-antennas determination unit 107 may detect the number of antennas connected to the port of the transmission unit 101, or the number of antennas specified in advance by a user, a higher system, or the like stored in a memory (not shown) or the like. The number of antennas may be acquired by reading the indicated information.

  (Step S203) The antenna number determination unit 107 determines whether or not the value of the number of antennas M acquired in step S204 is 2 or more. When it is not 2 or more, the process proceeds to step S204, and when it is 2 or more, the process proceeds to step S205.

  (Step S204) The communication processing device 1 performs a first communication process that is a communication process when the number M of antennas is one. And a process is complete | finished after completion | finish of a 1st communication process. The first communication process will be described later with reference to FIG.

  (Step S205) The communication processing device 1 performs a second communication process that is a communication process when the number M of antennas is 2 or more. And a process is complete | finished after completion | finish of a 2nd communication process. The second communication process will be described later with reference to FIG.

If information about whether or not the number of antennas is 2 or more is known in advance, it is specified whether to perform the first communication process or the second communication process instead of step S202 and step S203. The number-of-antenna determination unit 107 receives the information to be transmitted via the transmission instruction reception unit 102 and the like, and the number-of-antenna determination unit 107 selects either the first communication process or the second communication process indicated by the received information. In such a case, the result is substantially the same as determining whether the number of antennas is 2 or more.
In the flowchart of FIG. 2, the process is terminated by powering off or a process termination interrupt.

  Next, the first communication process in step S204 of FIG. 2 will be described using the flowchart of FIG.

  (Step S301) The free channel detection unit 109 substitutes 1 for a counter n.

  (Step S302) The free channel detection unit 109 executes processing for detecting a free channel using information received by the reception unit 103. The process for detecting an empty channel executed by the empty channel detection unit 109 is, for example, an LBT process. Since the LBT process is a known technique, a description thereof will be omitted.

  (Step S303) The empty channel detection unit 109 determines whether or not an empty channel has been detected by the process of step S302. If an empty channel can be detected, the process proceeds to step S307, and if it cannot be detected, the process proceeds to step S304.

  (Step S304) The free channel detection unit 109 determines whether or not the value of the counter n is equal to or greater than L (L is an integer equal to or greater than 2). The value of L is an upper limit value of the number of repetitions when the LBT process is repeated. It is assumed that the value of L is designated in advance by the user or the like. However, it may be received from the host system or the like via the transmission instruction receiving unit 102 or the like. If it is greater than or equal to L, the process proceeds to step S305, and if not greater than L, the process proceeds to step S306.

  (Step S305) The output unit 104 outputs information indicating that there is no empty channel to a higher system such as a computer. Then, the process returns to the upper function. Note that the information indicating that there is no empty channel may be information indicating that communication has failed or an error has occurred. In addition, this process may be omitted when information indicating that there is no empty channel is not transmitted. Further, after waiting for a predetermined time, the processing from step S302 may be performed again.

  (Step S306) The free channel detection unit 109 increments the counter n by 1. Then, the process returns to step S302.

  (Step S307) The absence detection unit 105 substitutes 1 for the counter p.

  (Step S308) The communication processing device 1 performs communication with the RFID tag. Specifically, the transmission unit 101 transmits a command according to the transmission instruction received by the transmission instruction reception unit 102 using the transmission antenna 111, and the information transmitted by the RFID tag in response to the transmission of the command is received by the reception unit. 103 receives using the receiving antenna 112. The received information is output from the output unit 104 to the host system or the like. If information from one or more RFID tags can be received, command transmission and information reception from the RFID tags are repeated until reception from all RFID tags is completed or until a preset time is reached. . Further, when a collision or the like occurs, communication is performed by performing an anti-collision process or the like. The communication control unit 110 or the like appropriately performs transmission / reception control and the like during this communication. In communication with the RFID tag, normally, after a command is transmitted by the transmission unit 101, the reception unit 103 did not detect the occurrence of a collision and did not receive a response from the RFID tag within a predetermined time. If finished.

  (Step S309) The absence detection unit 105 detects whether or not the RFID tag is absent. If there is no response to the transmission of the command from the transmission unit 101 in step S308, it is determined that communication with the RFID tag has not been successful, and if there is a response, it is not absent, that is, the RFID tag Judge that it exists. Note that it may be determined whether or not the RFID tag is absent by determining whether or not the communication with the RFID tag is successful. In this case, when the communication with the RFID tag fails, the absence of the RFID tag is detected, and when the communication with the RFID tag is successful, the presence of the RFID tag is detected. That's fine. If the RFID tag is absent, the process proceeds to step S310. If the RFID tag is present, in step S308, the communication is successful, and the process returns to the upper function.

  (Step S310) The absence detection unit 105 determines whether or not the value of the counter p is equal to or greater than R (R is an integer equal to or greater than 2). The value of R is an upper limit value of the number of repetitions of processing for causing the transmission unit 101 to retransmit the command. The value of R is assumed to be designated in advance by the user or the like. However, it may be received from the host system or the like via the transmission instruction receiving unit 102 or the like. If it is greater than or equal to R, the process proceeds to step S311, and if not greater than R, the process proceeds to step S312.

  (Step S311) The output unit 104 outputs information indicating that the RFID tag is not in the communication area to a host system such as a computer. Then, the process returns to the upper function. Note that the information indicating that the RFID tag is not in the communication area may be information indicating that communication has failed or an error has occurred. Further, this process may be omitted when information indicating that the RFID tag is not in the communication area is not transmitted. Further, after waiting for a predetermined time, the processing from step S301 may be performed again. The predetermined time in this case is a transmission stop time. In the case of the communication processing device 1 for UHF band RFID tags, it is necessary to set at least a time obtained by subtracting the time required for the LBT processing from 50 ms or 50 ms. .

  (Step S312) The absence detection unit 105 increments the counter p by 1.

  (Step S313) The retransmission instruction unit 106 instructs the transmission unit 101 to retransmit a command within one transmission period. Then, the process returns to step S308.

  In the flowchart of FIG. 3, the process ends when the power is turned off or the process is terminated.

  Next, the second communication process in step S205 of FIG. 2 will be described using the flowchart of FIG.

  (Step S401) The switching instruction unit 108 substitutes 1 for the counter k.

  (Step S402) The switching instruction unit 108 instructs the transmission unit 101 and the reception unit 103 to switch the transmission antenna 111 and the reception antenna 112 used for transmission and reception to the kth transmission antenna 111 and the reception antenna 112.

  (Step S403) The vacant channel detection unit 109 executes processing for detecting an vacant channel using information received by the reception unit 103 using the kth reception antenna 112. The process for detecting an empty channel executed by the empty channel detection unit 109 is, for example, an LBT process. Since the LBT process is a known technique, a description thereof will be omitted.

  (Step S404) The free channel detection unit 109 determines whether or not a free channel has been detected by the process of step S403. If an empty channel can be detected, the process proceeds to step S408, and if it cannot be detected, the process proceeds to step S405.

  (Step S405) When the k-th transmitting antenna 111 and receiving antenna 112 are used, the output unit 104 outputs information indicating that there is no empty channel to a higher system such as a computer. Then, the process returns to the upper function. Note that the information indicating that there is no empty channel may be information indicating that communication has failed or an error has occurred. In addition, this process may be omitted when information indicating that there is no empty channel is not transmitted. Then, the process proceeds to step S406.

  (Step S406) The switching instruction unit 108 determines whether or not the counter k is equal to or greater than the number M of antennas. If it is greater than or equal to M, the process returns to the upper function, and if not greater than M, the process proceeds to step S407. In addition, when it is M or more, you may make it perform the process from step S401 again.

  (Step S407) The switching instruction unit 108 increments the counter k by 1. Then, the process returns to step S402.

  (Step S <b> 408) The communication processing apparatus 1 performs communication with the RFID tag using the kth transmission antenna 111 and reception antenna 112. Specifically, the transmission unit 101 transmits a command according to the transmission instruction received by the transmission instruction reception unit 102 using the transmission antenna 111, and the information transmitted by the RFID tag in response to the transmission of the command is received by the reception unit. 103 receives using the receiving antenna 112. The received information is output from the output unit 104 to the host system or the like. If information from one or more RFID tags can be received, command transmission and information reception from the RFID tags are repeated until reception from all RFID tags is completed or until a preset time is reached. . Further, when a collision or the like occurs, communication is performed by performing an anti-collision process or the like. The communication control unit 110 or the like appropriately performs transmission / reception control and the like during this communication. In the communication processing with the RFID tag, normally, the receiving unit 103 does not detect the occurrence of the collision and does not receive the response from the RFID tag within a predetermined time after the transmission unit 101 transmits the command. Exit if

  (Step S409) The absence detection unit 105 detects whether or not the RFID tag is absent in the communication area of the kth transmission antenna 111 and reception antenna 112. If there is no response to the transmission of the command from the transmission unit 101 in step S408, it is determined that communication with the RFID tag has not been successful, and if there is a response, it is not absent, that is, the RFID tag Judge that it exists. Note that it may be determined whether or not the RFID tag is absent by determining whether or not the communication with the RFID tag is successful. In this case, when the communication with the RFID tag fails, the absence of the RFID tag is detected, and when the communication with the RFID tag is successful, the presence of the RFID tag is detected. That's fine. If the RFID tag is absent, the process proceeds to step S411. If the RFID tag is present, in step S408, it indicates that the communication has been successful, and the process proceeds to step S410.

  (Step S410) The communication processing apparatus 1 determines whether or not a predetermined time has elapsed since the end of transmission / reception in step S408. The predetermined time is the time of the transmission stop period. For example, when the communication processing device 1 is a communication processing device for an RFID tag in the UHF band, in Japan, at least 50 ms or more based on radio law. Or the time obtained by subtracting the time required for the LBT processing from this 50 ms. If the predetermined time has elapsed, the process proceeds to step S406. If not, the process returns to step S410. This process may be performed by any part of the communication processing apparatus 1 such as the communication control unit 110.

  (Step S411) The output unit 104 outputs information indicating that the RFID tag is not within the communication area of the k-th antenna to a host system such as a computer. Then, the process proceeds to step S410. Note that the information indicating that the RFID tag is not within the communication area of the k-th antenna may be information indicating that communication has failed or an error has occurred. In addition, this process may be omitted when information indicating that the RFID tag is not within the communication area of the k-th antenna is not transmitted. Note that the process of step S411 may be executed before or after step S407 or step S403, for example.

  In the flowchart of FIG. 4, the process ends when the power is turned off or the process ends.

  Hereinafter, a specific operation of the communication processing apparatus 1 in the present embodiment will be described. The conceptual diagram of the communication processing apparatus 1 is FIG. FIG. 5 is a diagram illustrating an example in which the communication processing device 1 is installed at a cargo entrance of a warehouse or the like. Here, it is assumed that four transmission / reception antennas 150a to 150d that serve as both the transmission antenna 111 and the reception antenna 112 are installed at the gate of the carry-in entrance or the like. The communication processing apparatus 1 has four transmission / reception ports 151, and transmission / reception antennas 150a to 150d are connected to the respective ports 151. Here, the RFID tag 50 is attached to a package that is carried into a warehouse or the like, so that the package that is carried in can be managed. It is assumed that a UHF band RFID tag is used as the RFID tag 50. Further, it is assumed that the communication processing apparatus 1 is connected to a computer 200 that is a higher-level system for managing a package or the like using information read from a tag attached to the package or the like.

  Here, first, as an example, a case will be described in which the communication processing device 1 is set to communicate with the RFID tag using only the transmission / reception antenna 150a. It is assumed that information for setting to use only the transmission / reception antenna 150a is stored in a memory or the like (not shown).

  First, it is assumed that the computer 200 outputs an instruction to read the RFID tag 50 attached to the package to the communication processing device 1 through the communication line.

  When the communication processing apparatus 1 receives an instruction to read the RFID tag 50 from the computer 200, the communication processing apparatus 1 determines whether or not a predetermined time set in advance, 50 ms, has elapsed since the end of the transmission / reception process performed immediately before. to decide. Here, it is assumed that 50 ms has elapsed.

  Next, the antenna number determination unit 107 determines the number of antennas M. Here, since information for setting to use only the transmission / reception antenna 150a is stored in a memory or the like in advance, the number-of-antenna determination unit 107 reads out this information. The number of antennas to be used is counted from the read information, and “1” is acquired as the number of antennas M here. Then, the antenna number determination unit 107 determines that the antenna number M is not 2 or more. Thereby, in the communication processing apparatus 1, the 1st communication process demonstrated in FIG. 3 will be performed.

  The empty channel detection unit 109 performs LBT processing for detecting an empty channel using information such as noise received by the reception unit 103. It is assumed that the LBT processing time is set in advance to 5 ms, which is the minimum required, for example, as the UHF band LBT processing time. Here, if an empty channel is not detected by one LBT process, this LBT process is repeated until a preset upper limit number of times is reached or an empty channel is detected. For example, it is assumed here that the upper limit number of repetitions is set to 3 times including the first LBT process. Here, since only one transmission / reception antenna 150a is used, repeated transmission / reception processing by this transmission / reception antenna 150a does not affect transmission / reception by other transmission / reception antennas.

  If no empty channel is detected when the LBT process is repeated three times, information indicating “no empty channel” is transmitted from the output unit 104 to the computer 200. For example, in the computer 200, it is possible to detect that the reading process was not successful based on the information indicating “no available channel”. For example, FIG. 6 shows a timing chart showing the relationship between the transmission / reception processing between the RFID tag 50 and the communication processing device 1 and the LBT processing. As shown in the figure, the LBT process is started 50 ms after the transmission / reception process performed immediately before, and the LBT process is completed after three LBT processes are repeated. In the timing chart shown in FIG. 6, the length in the time axis direction is assumed to be appropriately changed for each portion for the sake of explanation. The same applies to other timing charts.

  Here, for example, it is assumed that an empty channel is detected when the LBT process is repeated twice. In this case, communication with the RFID tag 50 is started by the communication processing device 1 using this empty channel.

  A command for reading the RFID tag 50 is transmitted from the transmission unit 101 via the transmission / reception antenna 150a. When the RFID tag 50 exists in the communication area of the transmission / reception antenna 150a, that is, when a package attached with the RFID tag 50 exists in the gate to which the transmission / reception antenna 150a is attached, the RFID tag 50 is removed from the transmission unit 101. Information is transmitted according to the transmitted command. Then, this information is received by the receiving unit 103 via the transmission / reception antenna 150a. Then, the received information is transmitted from the output unit 104 to the computer 200. This process is repeated until reading of all RFID tags 50 is completed. However, the upper limit of repetition is 4 seconds due to Japanese radio law. Thereby, the information of the RFID tag 50 is read. Such reading processing of information from the RFID tag, anti-collision processing, and the like are well-known techniques, and thus description thereof is omitted.

  When the RFID tag 50 does not exist in the communication area of the transmission / reception antenna 150, the RFID tag 50 that transmits information according to the command transmitted from the transmission unit 101 is absent. The response from the RFID tag cannot be obtained within the time for reception.

  The absence detection unit 105 determines that the RFID tag is absent in the communication area of the transmission / reception antenna 150a from the reception state that the reception unit 103 cannot obtain a response from the RFID tag according to the command.

  In this case, when the transmission period ends, an empty channel detected by the LBT process is released, which is not efficient. For this reason, without instructing the transmission period, information for instructing the retransmission of the command to the transmission unit 101 is output to the retransmission instruction unit 106 within one transmission period. The transmission unit 101 performs command retransmission in response to a retransmission instruction from the retransmission instruction unit 106. Such processing is repeated until a preset upper limit number of times is reached or a response from the RFID tag 50 is obtained. For example, it is assumed here that the upper limit number of repetitions is set to four times including the first command transmission at the start of the transmission period. Here, since only one transmission / reception antenna 150a is used, if the response from the RFID tag cannot be obtained, the efficiency of the communication processing apparatus 1 is not adversely affected even if the transmission period is not immediately terminated.

  When a response from the RFID tag 50 is not obtained when the command transmission is repeated four times, information indicating “no RFID tag” is transmitted from the output unit 104 to the computer 200. For example, the computer 200 can detect that there is no RFID tag to be read based on the information indicating “no RFID tag”. For example, FIG. 7 shows a timing chart showing the relationship between the transmission / reception processing between the RFID tag 50 and the communication processing device 1 and the LBT processing. As shown in the figure, when the LBT process for three times is repeated, an empty channel is detected, and a command is transmitted from the transmission unit 101 four times using the empty channel. "Is output.

  Here, for example, when a response from the RFID tag 50 is obtained before the command transmission is repeated four times, the transmission unit 101 and the reception unit 103 perform normal reading processing using the transmission / reception antenna 150a. Executed. For example, as shown in FIG. 8, when a response is first obtained from the RFID tag 50 for the second transmission of a command within one transmission period, reading from the RFID tag 50 ends thereafter. Until this time, normal transmission / reception processing, here, reading of information from the RFID tag 50 is performed.

  Next, as an example, a case will be described in which the communication processing device 1 is set to communicate with the RFID tag using the four transmission / reception antennas 150a to 150d in order. It is assumed that information for setting use of the transmission / reception antennas 150a to 150d is stored in a memory or the like (not shown).

  When the communication processing apparatus 1 receives an instruction to read the RFID tag 50 from the computer 200, the communication processing apparatus 1 determines whether or not a predetermined time set in advance, 50 ms, has elapsed since the end of the transmission / reception process performed immediately before. to decide. Here, it is assumed that 50 ms has elapsed.

  Next, the antenna number determination unit 107 reads information for setting to use the transmission / reception antennas 150a to 150d stored in a memory or the like, and counts the number of antennas to be used from the read information. “4” is acquired as the number of antennas M. Then, the antenna number determination unit 107 determines that the antenna number M is 2 or more. Thereby, in the communication processing apparatus 1, the 2nd communication process demonstrated in FIG. 4 will be performed.

  The switching instruction unit 108 first outputs an instruction to switch the transmission / reception antenna 150a, which is the first transmission / reception antenna, to the antenna used for transmission / reception to the transmission unit 101 and the reception unit 103. In response to this instruction, the transmission unit 101 and the reception unit 103 switch the antenna used for transmission and reception to the transmission / reception antenna 150a. Here, as a result, it is considered to switch that the antenna specified by the switching instruction is used by the transmission unit 101 and the reception unit 103.

  The vacant channel detection unit 109 performs LBT processing for detecting an vacant channel using information such as noise received by the reception unit 103 using the transmission / reception antenna 150a. It is assumed that the LBT processing time is set in advance to 5 ms, which is the minimum required, for example, as the UHF band LBT processing time. Here, assuming that an empty channel is not detected by the LBT process, the switching instruction unit 108 gives an instruction to switch the antenna to be used from the transmission / reception antenna 150a to the transmission / reception antenna 150b which is the second transmission / reception antenna. The data is output to the receiving unit 103. Then, the LBT process is performed again with the transmission / reception antenna 150b selected in accordance with the switching instruction. Thus, when an empty channel is not found, an antenna is switched immediately and LBT processing is performed, so that a plurality of antennas can be used efficiently.

  Thereafter, until an empty channel is found, similarly, the LBT processing is performed by switching the transmission / reception antennas 150c and 150d. When an empty channel is not found by the LBT process using the transmission / reception antenna 150d, the LBT process is terminated, and information indicating “no empty channel” is transmitted from the output unit 104 to the computer 200. For example, FIG. 9 shows a timing chart showing the relationship between the transmission / reception processing between the RFID tag 50 and the communication processing device 1 and the LBT processing. As shown in the figure, after 50 ms has passed since the transmission / reception process performed immediately before, the LBT process is started while sequentially switching the transmission / reception antennas 150a to 150d, and after the LBT process using the transmission / reception antenna 150d is repeated, there is no free space. Information indicating “no channel” is output, and the process ends.

  Here, for example, it is assumed that an empty channel is detected in the LBT processing using the transmission / reception antenna 150b. In this case, communication with the RFID tag 50 using the transmission / reception antenna 150b is started by the communication processing device 1 using this empty channel.

  A command for reading the RFID tag 50 is transmitted from the transmission unit 101 via the transmission / reception antenna 150b.

  Here, when the RFID tag 50 does not exist within the communication area of the transmission / reception antenna 150b, the RFID tag 50 that transmits information according to the command transmitted from the transmission unit 101 is absent. A response from the RFID tag cannot be obtained within a preset time for reception.

  The absence detection unit 105 determines that the RFID tag is absent in the communication area of the transmission / reception antenna 150b from the reception state that the reception unit 103 cannot obtain a response from the RFID tag according to the command.

  In this case, if the transmission period is continued, transmission / reception with an RFID tag using another transmission / reception antenna cannot be performed despite the absence of the RFID tag, which is not efficient. For this reason, the transmission period ends. Then, the switching instruction unit 108 outputs an instruction to switch the antenna used by the transmission unit 101 and the reception unit 103 to the remaining transmission / reception antennas, here, the transmission / reception antenna 150c, to the transmission unit 101 and the reception unit 103.

  The vacant channel detection unit 109 performs LBT processing in the same manner as described above using information received by the transmission / reception antenna 150c when 50 ms elapses from the end of transmission / reception processing of the transmission / reception antenna 150b. If an empty channel is detected, the communication processing device 1 starts communication with the RFID tag 50 using the transmission / reception antenna 150c.

  Here again, assuming that the RFID tag 50 does not exist in the communication area of the transmission / reception antenna 150c, the transmission period ends when the absence of the RFID tag is detected, as in the case of using the transmission / reception antenna 150b. Then, the switching instruction unit 108 outputs an instruction to switch the antennas used by the transmission unit 101 and the reception unit 103 to the remaining transmission / reception antennas, here, the transmission / reception antenna 150d, to the transmission unit 101 and the reception unit 103.

  Then, the transmission / reception antenna is switched to the transmission / reception antenna 150d, and the LBT process is performed again. Here, if an empty channel is detected in the LBT processing using the transmission / reception antenna 150d, the communication processing device 1 starts communication with the RFID tag 50 using the transmission / reception antenna 150d using the empty channel. The

  When the RFID tag 50 exists in the communication area of the transmission / reception antenna 150d, the RFID tag 50 transmits information according to the command transmitted from the transmission unit 101. Then, this information is received by the receiving unit 103 via the transmission / reception antenna 150d. Then, the received information is transmitted from the output unit 104 to the computer 200. This process is repeated until reading of all RFID tags 50 is completed. When the reading is finished, the transmission period is finished. However, the upper limit of repetition is 4 seconds due to Japanese radio law. Thereby, the information of the RFID tag 50 is read. Such reading processing of information from the RFID tag, anti-collision processing, and the like are well-known techniques, and thus description thereof is omitted. For example, FIG. 10 is a timing chart showing the relationship between transmission / reception processing between the RFID tag 50 and the communication processing device 1 and LBT processing when an empty channel is detected when the transmission / reception antennas 150b to 150d are used. Show.

  As described above, according to the present embodiment, when the absence of the RFID tag is detected within one transmission period, the transmission unit 101 retransmits the command, and in particular, the transmission antenna 111 and the reception antenna 112. In such a case, the detected empty channel can be used efficiently, and efficient communication with the RFID tag becomes possible.

  Further, according to the present embodiment, when it is determined that the number of pairs of the transmission antenna 111 and the reception antenna 112 is two or more, and when the absence of the RFID tag is detected within one transmission period, In this case, an instruction to switch the transmission antenna 111 and the reception antenna 112 is output, and it is determined that the number of pairs of the transmission antenna 111 and the reception antenna 112 is not two or more, and the RFID tag is transmitted within one transmission period. Since the transmission unit 101 resends the command when the absence of the RFID tag is detected, when the number of the transmission antennas 111 and the reception antennas 112 to be used is one pair, the RFID tag is absent. The transmission unit 101 retransmits the command so that the empty channel can be used efficiently, and the transmission antenna 111 and reception used When the number of the antennas 112 is two or more and the RFID tag is absent, the pair of the transmission antenna 111 and the reception antenna 112 is switched, and the RFID tag is changed by the different transmission antenna 111 and reception antenna 112. The plurality of transmission antennas 111 and reception antennas 112 can be efficiently used by performing communication with the communication. Thus, according to the present embodiment, when an RFID tag is not detected during communication using each transmission antenna 111 and reception antenna 112 according to the number of pairs of transmission antenna 111 and reception antenna 112. It is possible to efficiently communicate by changing whether to retransmit the command.

  Further, according to the present embodiment, when it is determined that the number of pairs of transmission antennas and reception antennas is 2 or more and an empty channel cannot be detected, the reception antenna is switched to an empty channel. When the number of pairs of transmission antennas and reception antennas is determined not to be 2 or more, and the empty channel cannot be detected, the detection of the empty channel is repeated. When the number of transmitting antennas 111 and receiving antennas 112 is a pair, and an empty channel cannot be detected, an empty channel can be detected efficiently by performing a process of detecting an empty channel again. An empty channel cannot be detected when the number of transmitting antennas 111 and receiving antennas 112 is two or more. In this case, the pair of the transmission antenna 111 and the reception antenna 112 can be switched, and an empty channel can be detected by the different transmission antenna 111 and reception antenna 112. Can be used efficiently. Thus, according to the present embodiment, an empty channel is not detected when an empty channel is detected using each transmitting antenna 111 and receiving antenna 112 according to the number of pairs of transmitting antenna 111 and receiving antenna 112. In this case, it is possible to efficiently communicate by changing whether or not to repeat the empty channel processing.

  In the present embodiment, in the first communication process described with reference to FIG. 3, when there is no vacant channel, a process of detecting a vacant channel, specifically, an LBT process is performed a maximum of L times. However, the process of detecting an empty channel may be performed until a predetermined time set in advance elapses, that is, until the time is up. Specifically, as in the flowchart shown in FIG. 11, in the flowchart shown in FIG. 3, instead of step S301, step S304, and step S306, the empty channel detection unit 109 performs the first LBT as step S1101. It is determined whether or not the elapsed time from the start of the process has reached a predetermined time. If the predetermined time has been reached, the process proceeds to step S305, and if not, the process proceeds to step S302. What is necessary is just to provide. This time may be measured using, for example, a clock (not shown) provided in the communication processing apparatus 1. In FIG. 11, the same reference numerals as those in FIG. 3 indicate the same or corresponding processing steps.

  In the present embodiment, in the first communication process described with reference to FIG. 3, when the communication with the tag is not successful, that is, the response from the RFID tag is transmitted with respect to the transmission of the command from the transmission unit 101. If the command cannot be obtained, command transmission from the transmission unit 101 is performed a maximum of R times, but the process of transmitting the command is repeated until a predetermined time elapses, that is, until the time is up. Anyway. Specifically, like the flowchart shown in FIG. 12, in the flowchart shown in FIG. 3, instead of step S307, step S310, and step S312, as the step S1201, the absence detecting unit 105 It is determined whether or not the elapsed time from the start of transmission of the first command has reached a predetermined time. If the predetermined time has been reached, the process proceeds to step S311. If not, the process proceeds to step S313. May be provided. This time may be measured using, for example, a clock (not shown) provided in the communication processing apparatus 1. In FIG. 12, the same reference numerals as those in FIG. 3 denote the same or corresponding processing steps.

  In the above embodiment, whether or not to retransmit a command when the RFID tag is absent is changed depending on the number of pairs of transmission antennas and reception antennas. In cases such as when only one pair of receiving antennas 112 is often used, depending on the number of pairs of transmitting antennas and receiving antennas, change whether to retransmit the command when the RFID tag is absent. 3, the process of repeating the retransmission of the command when the RFID tag is absent, as shown in steps S307 to S310 in FIG. 3, is performed with the RFID tag using each transmission antenna and reception antenna pair. You may make it always perform, when performing communication.

  In the above embodiment, whether or not to repeat the empty channel detection process is changed depending on the number of pairs of transmission antennas and reception antennas, and the RFID tag is absent depending on the number of pairs of transmission antennas and reception antennas. In this case, whether or not to retransmit the command is changed. However, only one of the two changes may be changed.

  For example, depending on the number of pairs of transmission antennas and reception antennas, it may be changed only whether or not to repeat the detection process of empty channels. In this case, for example, the processing steps of Step S307, Step S310, Step S312 and Step S313 may be omitted in the flowchart of FIG.

  Further, depending on the number of pairs of transmission antennas and reception antennas, whether or not to retransmit a command when the RFID tag is absent may be changed. In this case, for example, in the flowchart of FIG. 3, the processing in step S301, step S304, and step S306 may be omitted.

  In each of the above embodiments, each process (each function) may be realized by centralized processing by a single device (system), or by distributed processing by a plurality of devices. May be.

  In each of the above embodiments, each component may be configured by dedicated hardware, or a component that can be realized by software may be realized by executing a program. For example, each component can be realized by a program execution unit such as a CPU reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory.

  The software that realizes the communication processing device in each of the above embodiments is the following program. That is, this program is a program for causing a computer to execute a communication process for communicating with an RFID tag. The program performs a transmission step of transmitting a command to the RFID tag, and reception of information transmitted from the RFID tag. A reception step to perform, an output step to output information received in the reception step, and an absence detection to detect the absence of an RFID tag according to the reception status of the reception step when the command is transmitted in the transmission step And a resending step of resending the command within one transmission period when the absence detecting step detects the absence of the RFID tag.

  Further, the program is a program for causing a computer to execute a communication process for performing communication with the RFID tag. The transmission step transmits a command to the RFID tag using one or more transmission antennas. A receiving step for receiving information transmitted from an RFID tag using one or more receiving antennas paired with one or more transmitting antennas; an output step for outputting information received in the receiving step; and the transmitting step When the command is transmitted using one transmission antenna among the one or more transmission antennas, according to the reception status by the reception step using one reception antenna corresponding to the one transmission antenna, The absence detection step for detecting the absence of the RFID tag and the number of pairs of the transmission antenna and the reception antenna are two. The number of antennas determining step for determining whether the number of antennas is above or not, and the transmitting step determines that the number of pairs of the transmitting antenna and the receiving antenna is 2 or more according to the antenna number determining step. If the absence of the RFID tag is detected in the absence detection step, the transmission antenna and the reception antenna are switched, and the number of antennas determination step determines the pair of the transmission antenna and the reception antenna. When the number is not two or more and the absence detection step detects the absence of the RFID tag, the program resends the command within one transmission period.

  Further, this program is a program for causing a computer to execute communication processing for communicating with an RFID tag using one of a plurality of channels, and using one or more transmission antennas, Of the information received in the reception step, a transmission step of transmitting a command to the tag, a reception step of receiving information using one or more reception antennas paired with the one or more transmission antennas, An empty channel used as a channel for communicating with the RFID tag using an output step of outputting information transmitted from the RFID tag and information received using one of the one or more receiving antennas And the number of pairs of the transmitting antenna and the receiving antenna is two or more. The number of antennas determining step for determining whether or not there is performed, and the empty channel detecting step determines that the number of pairs of the transmitting antenna and the receiving antenna is 2 or more in the number of antennas determining step. If the empty channel detection unit cannot detect an empty channel, the reception antenna is switched to detect an empty channel, and the number of antennas determining step determines the pair of the transmission antenna and the reception antenna. This is a program that repeats the detection of an empty channel when it is determined that the number of channels is not 2 or more and an empty channel cannot be detected in the empty channel detection step.

  In the above program, in a transmission step for transmitting information, a reception step for receiving information, etc., processing performed by hardware, for example, processing performed by a modem or an interface card in the transmission step (only performed by hardware). Not included) is not included.

  The program may be executed by being downloaded from a server or the like, and a program recorded on a predetermined recording medium (for example, an optical disk such as a CD-ROM, a magnetic disk, a semiconductor memory, or the like) is read out. May be executed by

  Further, the computer that executes this program may be singular or plural. That is, centralized processing may be performed, or distributed processing may be performed.

  In each of the above embodiments, it goes without saying that two or more communication means (such as a transmission unit and a reception unit) existing in one device may be physically realized by one medium.

  The present invention is not limited to the above-described embodiments, and various modifications are possible, and it goes without saying that these are also included in the scope of the present invention.

  As described above, the communication processing apparatus according to the present invention is suitable as a communication processing apparatus that performs communication with an RFID tag, and is particularly useful as a communication processing apparatus that performs communication with a UHF band RFID tag.

Block diagram of a communication processing apparatus in an embodiment Flow chart for explaining the operation of the communication processing apparatus Flow chart for explaining the operation of the communication processing apparatus Flow chart for explaining the operation of the communication processing apparatus Conceptual diagram Diagram for explaining the operation of the communication processing apparatus Diagram for explaining the operation of the communication processing apparatus Diagram for explaining the operation of the communication processing apparatus Diagram for explaining the operation of the communication processing apparatus Diagram for explaining the operation of the communication processing apparatus Flowchart for explaining the operation of a modification of the communication processing apparatus Flowchart for explaining the operation of a modification of the communication processing apparatus

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Communication processing device 50 RFID tag 101 Transmission part 102 Transmission instruction | indication reception part 103 Reception part 104 Output part 105 Absence detection part 106 Retransmission instruction | indication part 107 Antenna number judgment part 108 Switching instruction | indication part 109 Channel detection part 110 Communication control part 111 Transmission antenna 112 Reception antenna 150, 150a to 150d Transmission / reception antenna 151 Port 200 Computer

Claims (6)

A communication processing device that communicates with an RFID tag using one of a plurality of channels,
A transmission unit that is connected to one or more transmission antennas and transmits a command to the RFID tag using the transmission antenna;
A receiving unit connected to one or more receiving antennas paired with the one or more transmitting antennas and receiving information using the receiving antennas;
Of the information received by the receiving unit, an output unit that outputs information transmitted from the RFID tag;
An empty channel detection unit that detects an empty channel used as a channel for communication with the RFID tag using information received using one of the one or more receiving antennas;
An antenna number determination unit for determining whether or not the number of pairs of the transmission antenna and the reception antenna is 2 or more;
The empty channel detection unit
When the number of antennas determination unit determines that the number of pairs of the transmission antenna and the reception antenna is 2 or more, and the empty channel detection unit cannot detect an empty channel, the reception unit Instructs the switching of the receiving antenna to detect an empty channel,
When the number-of-antenna determination unit determines that the number of pairs of the transmission antenna and the reception antenna is not 2 or more, and the empty channel detection unit cannot detect the empty channel, the detection of the empty channel is performed. Communication processing device that repeats. The number of antennas determination unit until the free channel is detected, the repetition of detection of the idle channel, the communication processing apparatus according to claim 1, wherein performing until a preset predetermined number of times. The number of antennas determination unit until the free channel is detected, the repetition of detection of the idle channel, the communication processing apparatus according to claim 1, wherein the performing until the elapse of the preset time period. The communication processing apparatus according to claim 1 , further comprising the one or more transmission antennas and the one or more reception antennas. A communication processing method for communicating with an RFID tag using one of a plurality of channels,
A transmission step of transmitting a command to the RFID tag using one or more transmission antennas;
A receiving step of receiving information using one or more receiving antennas paired with the one or more transmitting antennas;
Of the information received in the receiving step, an output step for outputting information transmitted from the RFID tag;
An empty channel detection step of detecting an empty channel used as a channel for communication with the RFID tag using information received using one of the one or more receiving antennas;
An antenna number determining step for determining whether or not the number of pairs of the transmitting antenna and the receiving antenna is 2 or more,
The empty channel detecting step includes
When it is determined in the antenna number determining step that the number of pairs of the transmission antenna and the receiving antenna is 2 or more, and the empty channel detection unit cannot detect an empty channel, the receiving antenna To detect empty channels,
When the number of antennas determining step determines that the number of pairs of the transmitting antenna and the receiving antenna is not 2 or more, and when the empty channel cannot be detected by the empty channel detecting step, the empty channel is detected. Communication processing method that repeats. A program for causing a computer to execute communication processing for communication with an RFID tag using one of a plurality of channels,
A transmission step of transmitting a command to the RFID tag using one or more transmission antennas;
A receiving step of receiving information using one or more receiving antennas paired with the one or more transmitting antennas;
Of the information received in the receiving step, an output step for outputting information transmitted from the RFID tag;
An empty channel detection step of detecting an empty channel used as a channel for communication with the RFID tag using information received using one of the one or more receiving antennas;
Performing an antenna number determination step of determining whether or not the number of pairs of the transmission antenna and the reception antenna is 2 or more;
The empty channel detecting step includes
When it is determined in the antenna number determining step that the number of pairs of the transmission antenna and the receiving antenna is 2 or more, and the empty channel detection unit cannot detect an empty channel, the receiving antenna To detect empty channels,
When the number of antennas determining step determines that the number of pairs of the transmitting antenna and the receiving antenna is not 2 or more, and when the empty channel cannot be detected by the empty channel detecting step, the empty channel is detected. A program that repeats.

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