JP4589404B2 - Interference determination device, data reader, RFID system, interference determination method, and interference determination program - Google Patents

Description

  The present invention relates to a technique for preventing interference between a radio wave used in an RFID (Radio Frequency IDentification) system and a predetermined radio wave, for example.

  Conventionally, automatic recognition (RFID) by non-contact data communication has been performed for individual management of articles and entrance / exit management. In the RFID system, an IC (Integrated Circuit) tag in which a unique ID (identifier) is written on an identification object such as an article or a person is pasted. Then, a data reader installed on the side of the gate or door supplies electric power to the IC tag using radio waves and transmits a unique ID read command. In the IC tag, a silicon chip built in the IC tag is driven by radio waves from the data reader. In response to a command from the data reader, the IC tag returns a response depending on whether information stored in the IC tag such as a unique ID is reflected or not with respect to an unmodulated radio wave emitted from the data reader. On the other hand, the data reader identifies the presence or absence of a reflected wave that is a response from the IC tag, and reads information stored in the IC tag such as a unique ID.

Since the data reader identifies the presence or absence of such a weak reflected wave, communication with the IC tag is hindered when another data reader using the same frequency is emitting radio waves in the vicinity. Will be. Therefore, the data reader checks whether another data reader using the same frequency nearby emits radio waves before emitting radio waves. Here, this operation of the data reader is referred to as carrier sense. As a result of carrier sense, when it becomes clear that another data reading device using the same frequency in the vicinity does not emit radio waves, communication with the IC tag is started. On the other hand, if another data reader using the same frequency nearby is emitting radio waves, switch the frequency to be used to another frequency, perform carrier sense again, and use a frequency that is not being used. Communicate with the IC tag.
JP-A-10-293824

Conventionally, it has been possible to prevent radio wave interference between a data reader and another data reader using conventional carrier sense. However, IC tags are assumed to be distributed worldwide. For this reason, the IC tag has been developed mainly for the purpose of reducing power consumption and reducing manufacturing costs for energy supply by radio waves. Therefore, an IC tag usually does not have a steep frequency selectivity. Therefore, radio wave interference between the data reading device and the IC tag cannot be prevented even if the conventional carrier sense is used. In other words, there has been a problem that if the IC tag that is communicating with the data reader with radio waves of a predetermined frequency is irradiated with radio waves of a different frequency, the IC tag malfunctions.
The embodiment of the present invention has been made to solve the above-described problem, and even when a data reader is newly arranged at a location where the data reader is present in the vicinity, the data read is performed. An object of the present invention is to prevent radio wave interference between the apparatus and another data reader and radio wave interference between the data reader and the IC tag.

An interference determination apparatus according to an embodiment of the present invention is an interference determination apparatus that determines whether a radio wave used in an RFID system including an IC tag and a data reader interferes with a predetermined radio wave.
A frequency designation unit that designates a designated frequency that is a frequency of the predetermined radio wave by an input device, and a first threshold that is a threshold of an interference level of the designated frequency designated by the frequency designation unit is set and stored in a storage device An interference level setting unit; a first interference level detection unit that detects a first detection value that is an interference level of the specified frequency; and stores the first detection value in a storage device; the first threshold set by the first interference level setting unit; A first comparison unit that compares the first detection value detected by one interference level detection unit and determines whether or not the first detection value is less than or equal to a first threshold by a processing device; and a plurality of allocations assigned to the RFID system A second interference level setting unit that sets a second threshold that is a threshold of an interference level of a designated frequency band that is a frequency band including the designated frequency of the frequency band and stores the second threshold in a storage device; and an interference level of the designated frequency band A second interference level detection unit that detects a second detection value and stores the second detection value in a storage device; a second threshold value set by the second interference level setting unit; and a second detection value detected by the second interference level detection unit. A second comparison unit that compares the second detection value by the processing device to determine whether or not the second detection value is equal to or less than a second threshold; and the first comparison unit determines that the first detection value is equal to or less than the first threshold; and When the second comparison unit determines that the second detection value is equal to or less than the second threshold value, the second comparison unit includes a determination unit that determines that the radio wave does not interfere with the processing device.

  Further, the second interference level detection unit of the interference determination device detects the interference level of each channel of the plurality of channels assigned to the designated frequency band as a second detection value, stores it in the storage device, and stores the second interference level in the storage device. The comparison unit compares the second threshold value with each second detection value for each channel detected by the second interference level detection unit, and determines whether each second detection value for each channel is equal to or less than the second threshold value. The determination unit determines that the first comparison unit determines that the first detection value is less than or equal to the first threshold value, and the second comparison unit determines that all the second detection values for each channel are less than or equal to the second threshold value. If it is determined that there is a radio wave, the radio wave is determined not to interfere.

  Furthermore, the second threshold value set by the second interference level setting unit of the interference determination apparatus is larger than the first threshold value set by the first interference level setting unit.

  Furthermore, the first interference level setting unit of the interference determination device sets a first threshold based on the magnitude of the output for transmitting the radio wave of the specified frequency, and the second interference level setting unit is configured to transmit the specified frequency. The second threshold value is set based on the magnitude of the output for transmitting the radio wave.

The interference determination device according to the embodiment of the present invention transmits a notification wave, which is a notification radio wave, to a predetermined frequency when an IC tag and a communication wave, which is a communication radio wave, are transmitted to the IC tag. In an interference determination device that determines whether or not a radio wave used in an RFID system and a predetermined radio wave interfere with a data reader that transmits to a notification channel assigned to
A frequency designation unit that designates a designated frequency that is a frequency of the predetermined radio wave by an input device, and a first threshold that is a threshold of an interference level of the designated frequency designated by the frequency designation unit is set and stored in a storage device An interference level setting unit; a first interference level detection unit that detects a first detection value that is an interference level of the specified frequency; and stores the first detection value in a storage device; the first threshold set by the first interference level setting unit; The first detection value detected by the first interference level detection unit is compared with the first comparison unit which is determined by the processing device to determine whether the first detection value is equal to or lower than the first threshold value, and the interference level threshold value of the notification channel. A notification channel interference level setting unit that sets a certain notification channel threshold value and stores it in the storage device, and a notification channel interference level that detects a notification channel detection value that is the interference level of the notification channel and stores it in the storage device The notification channel threshold set by the output unit and the notification channel interference level setting unit is compared with the notification channel detection value detected by the notification channel interference level detection unit, and whether or not the notification channel detection value is equal to or less than the notification channel threshold. A notification channel comparison unit that is determined by the processing device, and the first comparison unit determines that the first detection value is equal to or less than a first threshold value, and the notification channel comparison unit determines the notification channel detection value equal to or less than a notification channel threshold value. When it determines with it being, it is provided with the determination part which determines with a processing apparatus that an electromagnetic wave does not interfere.

  Furthermore, the notification channel threshold set by the notification channel interference level setting unit of the interference determination apparatus is larger than the first threshold set by the first interference level setting unit.

  Further, the first interference level setting unit of the interference determination device sets a first threshold based on the magnitude of the output for transmitting the radio wave of the specified frequency, and the notification channel interference level setting unit is configured to transmit the specified frequency. The notification channel threshold is set based on the magnitude of the output for transmitting the radio wave.

In addition, an interference determination apparatus according to an embodiment of the present invention transmits an IC (Integrated Circuit) tag and a radio wave having a predetermined frequency to the IC tag, and receives a radio wave having a frequency different from the predetermined frequency from the IC tag. In an interference determination device that determines whether a radio wave used in an RFID (Radio Frequency IDentification) system including a data reader interferes with a predetermined radio wave,
A frequency designation unit that designates a designated frequency that is a frequency of the predetermined radio wave by an input device, and a threshold of an interference level of a designated frequency band that is a frequency band including the designated frequency of a plurality of frequency bands assigned to the RFID system. A second interference level setting unit that sets a second threshold value and stores it in a storage device; a second interference level detection unit that detects a second detection value that is an interference level in the designated frequency band; The second threshold value set by the second interference level setting unit and the second detection value detected by the second interference level detection unit are compared, and it is determined by the processing device whether or not the second detection value is less than or equal to the second threshold value. And a determination unit that determines, by the processing device, that radio waves do not interfere when the second comparison unit determines that the second detection value is equal to or less than the second threshold value.

  Further, the second interference level setting unit of the interference determination device sets the second threshold based on the magnitude of the output for transmitting the radio wave of the specified frequency.

An interference determination apparatus according to an embodiment of the present invention is an interference determination apparatus that determines whether or not a radio wave used in an RFID system including an IC tag and a data reader interferes with a predetermined radio wave. ,
A frequency designation unit that designates a designated frequency that is a frequency of the predetermined radio wave by an input device, and a first threshold that is a threshold of an interference level of the designated frequency designated by the frequency designation unit is set and stored in a storage device An interference level setting unit; a first interference level detection unit that detects a first detection value that is an interference level of the specified frequency; and stores the first detection value in a storage device; the first threshold set by the first interference level setting unit; A first comparison unit that compares the first detection value detected by the one interference level detection unit and determines whether or not the first detection value is equal to or less than a first threshold by a processing device; A peripheral frequency interference level setting unit that sets a peripheral frequency threshold value that is a threshold value of an interference level of the peripheral frequency and stores it in a storage device with a predetermined frequency as a peripheral frequency, and an interference level of the peripheral frequency A peripheral frequency interference level detection unit that detects a side frequency detection value and stores it in a storage device, a peripheral frequency threshold set by the peripheral frequency interference level setting unit, and a peripheral frequency detection value detected by the peripheral frequency interference level detection unit The peripheral frequency comparison unit that determines whether or not the peripheral frequency detection value is equal to or lower than the peripheral frequency threshold value by the processing device, and the first comparison unit determines that the first detection value is equal to or lower than the first threshold value; When the peripheral frequency comparison unit determines that the peripheral frequency detection value is equal to or lower than the peripheral frequency threshold, the processing unit includes a determination unit that determines that radio waves do not interfere with each other.

  Further, the peripheral frequency threshold set by the peripheral frequency interference level setting unit of the interference determination device is larger than the first threshold set by the first interference level setting unit.

  Further, the peripheral frequency interference level setting unit of the interference determination device sets each frequency of a plurality of predetermined frequencies within a predetermined range from the specified frequency as a peripheral frequency, and the more the peripheral frequency is away from the specified frequency, The peripheral frequency threshold is set to a large value, the peripheral frequency interference level detection unit detects a peripheral frequency detection value of each of the plurality of predetermined frequencies, and the peripheral frequency comparison unit includes the plurality of predetermined frequencies. The peripheral frequency threshold value and the peripheral frequency detection value are compared for each frequency to determine whether the peripheral frequency detection value is equal to or less than the peripheral frequency threshold value. The determination unit includes the first comparison unit. It is determined that one detection value is equal to or less than the first threshold value, and the peripheral frequency comparison unit surrounds the peripheral frequency detection value for all the predetermined frequencies. If it is determined to be less than or equal to the wave number threshold, radio waves, characterized in that it is determined that no interference.

  Further, the data reader according to the embodiment of the present invention transmits a command to the IC tag by the communication device when the interference determination device and the determination unit of the interference determination device determine that the radio wave does not interfere. A transmission unit and a reception unit that receives a response to the command transmitted from the IC tag from the IC tag are provided.

An RFID system according to an embodiment of the present invention is an RFID system including the data reading device and an IC tag.
The IC tag performs processing based on an IC tag receiving unit that receives a command transmitted from the transmitting unit of the data reader by the communication device, and a command received by the IC tag receiving unit, and transmits a processing result by the communication device. And an IC tag transmission unit.

Furthermore, an interference determination method according to an embodiment of the present invention is an interference determination apparatus that determines whether a radio wave used in an RFID system including an IC tag and a data reader interferes with a predetermined radio wave. In the interference judgment method,
A frequency designation step in which a frequency designation unit designates a designated frequency that is a frequency of the predetermined radio wave by an input device, and a first threshold that is a threshold of an interference level of the designated frequency designated in the frequency designation step is set to a first interference level. A first interference level setting step which is set by the unit and stored in the storage device, and a first interference level detection step in which the first interference level detection unit detects and stores the first detection value which is the interference level of the specified frequency in the storage device The first comparison unit compares the first threshold value set in the first interference level setting step and the first detection value detected in the first interference level detection step, and the first detection value is less than or equal to the first threshold value. A first comparison step in which the first comparison unit determines whether or not there is a frequency band including the specified frequency of the plurality of frequency bands allocated to the RFID system; A second interference level setting unit that sets a second threshold value that is a threshold value of an interference level in the frequency band and stores the second threshold value in a storage device; and a second detection value that is an interference level in the designated frequency band is A second interference level detection step detected by the two interference level detection unit and stored in the storage device; a second threshold value set in the second interference level setting step; and a second detection value detected in the second interference level detection step The second comparison unit compares the second detection value and the second comparison unit determines whether the second detection value is equal to or less than the second threshold by the processing device, and the first detection value in the first comparison step. A determination step in which the determination unit determines that the radio wave is not interfered by the processing device when it is determined that the second detection value is equal to or less than the second threshold value in the second comparison step; Having And features.

Further, the interference determination program according to the embodiment of the present invention is an interference determination that determines whether or not a radio wave used in an RFID system including an IC tag and a data reader interferes with a predetermined radio wave. In the device interference judgment program,
A frequency designation step in which a frequency designation unit designates a designated frequency that is a frequency of the predetermined radio wave by an input device, and a first threshold that is a threshold of an interference level of the designated frequency designated in the frequency designation step is set to a first interference level. A first interference level setting step which is set by the unit and stored in the storage device, and a first interference level detection step in which the first interference level detection unit detects and stores the first detection value which is the interference level of the specified frequency in the storage device The first comparison unit compares the first threshold value set in the first interference level setting step and the first detection value detected in the first interference level detection step, and the first detection value is less than or equal to the first threshold value. A first comparison step in which the first comparison unit determines whether or not there is a frequency band including the specified frequency of the plurality of frequency bands allocated to the RFID system; A second interference level setting unit that sets a second threshold value that is a threshold value of an interference level in the frequency band and stores the second threshold value in a storage device; and a second detection value that is an interference level in the designated frequency band is A second interference level detection step detected by the two interference level detection unit and stored in the storage device; a second threshold value set in the second interference level setting step; and a second detection value detected in the second interference level detection step The second comparison unit compares the second detection value and the second comparison unit determines whether the second detection value is equal to or less than the second threshold by the processing device, and the first detection value in the first comparison step. A determination step in which the determination unit determines that the radio wave is not interfered by the processing device when it is determined that the second detection value is equal to or less than the second threshold value in the second comparison step; The computer Characterized in that to execute the.

  According to the interference determination apparatus according to the embodiment of the present invention, the first comparison unit determines the presence or absence of radio wave interference between the data reading device and the data reading device, and the second comparison unit uses the data reading device and the IC. It is possible to determine the presence or absence of radio wave interference with the tag. Accordingly, it is possible to prevent radio wave interference between the data reading device and another data reading device and radio wave interference between the data reading device and the IC tag.

First, the hardware configuration of the data reading apparatus 100 according to the embodiment will be described with reference to FIG. FIG. 1 is a diagram illustrating an example of a hardware configuration of a data reading apparatus 100 according to the embodiment.
In FIG. 1, the data reading apparatus 100 includes a CPU (Central Processing Unit) 911 that executes a program. The CPU 911 is connected to a ROM 913, a RAM 914, a communication board 915, an LCD (liquid crystal display) 901, a touch panel 902, an FDD (Flexible Disk) 904, a CDD 905, and a magnetic disk device 920 via a bus 912. A CPU or the like is an example of the processing device 980.
The RAM 914 is an example of a volatile memory. The ROM 913 and the magnetic disk device 920 are examples of a nonvolatile memory. These are examples of the storage device 984.
The communication board 915 is connected to a wireless antenna, a LAN 942, and the like. The communication board 915, the wireless antenna, and the like are examples of the communication device 986.
The touch panel 902 and the like are examples of the input device 982.

Here, the communication board 915 is not limited to the LAN 942 but may be directly connected to the Internet 940 or a WAN (Wide Area Network) such as ISDN. When directly connected to the Internet 940 or a WAN such as ISDN, the data reading apparatus 100 is connected to the Internet 940 or a WAN such as ISDN, and the gateway 941 is unnecessary.
The magnetic disk device 920 stores an operating system (OS) 921, a window system 922, a program group 923, and a file group 924. The program group 923 is executed by the CPU 911, the OS 921, and the window system 922.

The program group 923 stores programs that execute functions described as “˜units” in the description of the embodiments described below. The program is read and executed by the CPU 911.
In the file group 924, what is described as “˜determination” and “˜determination” in the description of the embodiment described below is stored as “˜file”.
Also, the arrows in the flowcharts described in the following description of the embodiments mainly indicate data input / output, and the data for the data input / output is the magnetic disk device 920, FD, optical disk, CD, MD. (Mini disc), DVD (Digital Versatile Disk) and other recording media. Alternatively, it is transmitted through a signal line or other transmission medium.

  In addition, what is described as “unit” in the description of the embodiment described below may be realized by firmware stored in the ROM 913. Alternatively, it may be implemented by software alone, hardware alone, a combination of software and hardware, or a combination of firmware.

  In addition, a program that implements the embodiment described below may be stored using a recording device using another recording medium such as the magnetic disk device 920, FD, optical disk, CD, MD, DVD, or the like.

Embodiment 1 FIG.
Next, the first embodiment will be described. In the first embodiment, a data reading apparatus 100 that prevents radio wave interference between the data reading apparatus 100 and another data reading apparatus 100 and radio wave interference between the data reading apparatus 100 and the IC tag 200 will be described. . Here, among the functions of the data reading apparatus 100, radio wave interference between the data reading apparatus 100 and another data reading apparatus 100 and radio wave interference between the data reading apparatus 100 and the IC tag 200 occur. The part that determines whether or not is an interference determination device.

  First, the function of the RFID system 300 including the data reading apparatus 100 and the IC tag 200 according to the first embodiment will be described with reference to FIG. FIG. 2 is a functional block diagram illustrating functions of the RFID system 300 including the data reading device 100 and the IC tag 200 according to the first embodiment.

  The data reading apparatus 100 includes a frequency designation unit 110, a first determination unit 120, a second determination unit 130, a determination unit 140, a transmission unit 150, a reception unit 160, a processing device 980, an input device 982, a storage device 984, and a communication device 986. Is provided.

  The frequency designating unit 110 designates a designated frequency, which is a frequency of a predetermined radio wave, which is determined by the interference determination device as to whether the radio wave used in the RFID system 300 interferes with the input device 982. That is, the interference determination device determines whether the radio wave used in the RFID system 300 interferes with the specified frequency. Here, the designated frequency is a frequency that the data reading apparatus 100 is trying to use.

The first determination unit 120 performs highly accurate carrier sense on the specified frequency specified by the frequency specifying unit 110. The reason for performing high-accuracy carrier sensing is, for example, to determine whether or not radio wave interference between the data reading device 100 and another data reading device 100 occurs. The first determination unit 120 includes a first interference level setting unit 122, a first interference level detection unit 124, and a first comparison unit 126.
The first interference level setting unit 122 sets a first threshold value that is a threshold value of the interference level of the designated frequency designated by the frequency designation unit 110 and stores the first threshold value in the storage device 984.
The first interference level detection unit 124 detects the first detection value that is the interference level of the designated frequency designated by the frequency designation unit 110 and stores it in the storage device 984. For example, the first interference level detection unit 124 detects the first detection value by detecting the intensity of the radio wave of the specified frequency.
The first comparison unit 126 compares the first threshold value set by the first interference level setting unit 122 with the first detection value detected by the first interference level detection unit 124, and the first detection value is equal to or less than the first threshold value. The processing device 980 determines whether or not there is any.
That is, for example, when the first comparison unit 126 determines that the first detection value is equal to or less than the first threshold value, the first determination unit 120 generates radio waves between the data reading device 100 and another data reading device 100. It is determined that no interference occurs.

The second determination unit 130 performs coarse carrier sense on the frequency band assigned to the RFID system 300 including the specified frequency specified by the frequency specifying unit 110. The reason for performing coarse carrier sense is, for example, to determine whether or not radio wave interference occurs between the data reader 100 and the IC tag 200. Here, the frequency band allocated to the RFID system 300 is a frequency band allocated to the RFID system 300 such as a 125 kHz band, a 13.56 MHz band, an 800/900 MHz band, and a 2.45 GHz band. The frequency band assigned to the RFID system 300 including the specified frequency is a frequency band including the specified frequency among the above frequency bands. The second determination unit 130 includes a second interference level setting unit 132, a second interference level detection unit 134, and a second comparison unit 136.
The second interference level setting unit 132 sets a second threshold value that is a threshold value of an interference level of a designated frequency band that is a frequency band including the designated frequencies of a plurality of frequency bands assigned to the RFID system 300 and stores the second threshold value in the storage device 984. To do. Here, since the first determination unit 120 normally performs high-accuracy carrier sense and the second determination unit 130 performs coarse-accuracy carrier sense, the second threshold is larger than the first threshold.
The second interference level detection unit 134 detects a second detection value that is an interference level in the designated frequency band and stores the second detection value in the storage device 984.
The second comparison unit 136 compares the second threshold value set by the second interference level setting unit 132 with the second detection value detected by the second interference level detection unit 134, and the second detection value is equal to or less than the second threshold value. The processing device 980 determines whether or not there is any.
That is, for example, when the second comparison unit 136 determines that the second detection value is equal to or less than the second threshold, the second determination unit 130 generates radio wave interference between the data reading device 100 and the IC tag 200. Judge that not.

  The determination unit 140 determines that the first comparison unit 126 determines that the first detection value is less than or equal to the first threshold value, and the second comparison unit 136 determines that the second detection value is less than or equal to the second threshold value, The processing device 980 determines that the radio wave does not interfere. Here, radio waves do not interfere with each other means that radio waves between the data reading device 100 and another data reading device 100 do not interfere, and that radio waves between the data reading device 100 and the IC tag 200 do not interfere. It is.

  When the determination unit 140 determines that the radio wave does not interfere, the transmission unit 150 transmits a command to the IC tag by the communication device 986. In other words, the transmission unit 150 does not interfere with radio waves between the data reading device 100 and another data reading device 100 and does not interfere with radio waves between the data reading device 100 and the IC tag 200. The command is transmitted by the communication device 986. Further, the transmission unit 150 transmits not only a command but also an unmodulated wave or the like.

  The receiving unit 160 receives a response to the command transmitted from the transmitting unit 150 from the IC tag.

The IC tag 200 includes an IC tag receiver 210 and an IC tag transmitter 220.
The IC tag receiving unit 210 receives the command transmitted from the transmitting unit 150 of the data reading device 100 by the communication device 986.
The IC tag transmission unit 220 performs processing based on the command received by the IC tag reception unit 210 and transmits the processing result by the communication device 986.

  Next, the interference level of the channel assigned to each frequency at a certain time will be described based on FIGS. FIG. 3 is a diagram showing an interference level (a) 410 of a channel assigned to each frequency at a certain time. FIG. 4 is a diagram showing the interference level (b) 420 of the channel assigned to each frequency at a certain time. 3 and 4, “CH-1” indicates channel 1, “CH-2” indicates channel 2, and “CH−” is read as a channel in the same manner. Here, it is assumed that each frequency in a certain frequency band assigned to the RFID system 300 is assigned to channel 1 to channel 9. In each of the interference level (a) 410 and the interference level (b) 420, the first interference level is a first threshold value and the second interference level is a second threshold value.

  At interference level (a) 410, channel 3, channel 6, channel 8, and channel 9 are below the first threshold. At interference level (a) 410, channel 1, channel 2, channel 4, and channel 7 are equal to or lower than the second threshold value. At interference level (a) 410, channel 5 is greater than the first threshold and greater than the second threshold.

  At interference level (b) 420, channel 3, channel 6, channel 8, and channel 9 are below the first threshold. At interference level (b) 420, channel 1, channel 2, channel 4, channel 5, and channel 7 are below the second threshold. Further, in the interference level (b) 420, there is no channel larger than the first threshold and larger than the second threshold.

  Next, the operation of the RFID system 300 including the data reader 100 and the IC tag 200 according to the first embodiment will be described with reference to FIG. FIG. 5 is a flowchart illustrating an interference determination method that is an operation of the RFID system 300 including the data reader 100 and the IC tag 200 according to the first embodiment.

  In the first interference level setting step and the second interference level setting step (S101), the first interference level setting unit 122 sets and stores a first threshold value which is an interference level threshold value of the designated frequency designated by the frequency designation unit 110. Store in device 984. In addition, the second interference level setting unit 132 sets a second threshold value that is a threshold value of an interference level of a designated frequency band that is a frequency band including designated frequencies of a plurality of frequency bands assigned to the RFID system 300, and the storage device 984. To remember. For example, the first interference level setting step and the second interference level setting step may be performed only when the data reader 100 is activated, or may be performed after a frequency specifying step (S102) described later.

  In the frequency designation step (S102), the frequency designation unit 110 uses the input device 982 to designate a designated frequency, which is a frequency of a predetermined radio wave that the interference determination device determines whether to interfere with the radio wave used in the RFID system 300. specify. For example, the frequency designation unit 110 may designate a channel assigned to the frequency as the designated frequency.

  In the first interference level detection step (S103), the first interference level detection unit 124 detects the first detection value that is the interference level of the designated frequency designated by the frequency designation unit 110, and stores it in the storage device 984.

  In the first comparison step (S104), the first comparison unit 126 compares the first threshold value set by the first interference level setting unit 122 with the first detection value detected by the first interference level detection unit 124, The processing device 980 determines whether or not one detection value is equal to or less than the first threshold value. If the first detection value is equal to or less than the first threshold value (YES in S104), the data reading apparatus 100 proceeds to the standby step (S105). On the other hand, when the first detection value is not equal to or less than the first threshold value (NO in S104), the data reading apparatus 100 proceeds to the frequency changing step (S113). That is, for example, when the first comparison unit 126 determines that the first detection value is equal to or less than the first threshold (YES in S104), the first determination unit 120 transmits radio waves to and from other data reading devices 100. It is determined that no interference occurs. Then, the data reading apparatus 100 proceeds to the standby step (S105) which is the next process. On the other hand, for example, when the first comparison unit 126 determines that the first detection value is not equal to or less than the first threshold (NO in S104), the first determination unit 120 interferes with radio waves with other data reading devices 100. Is determined to occur. Then, the data reading apparatus 100 proceeds to the frequency changing step (S113), changes the designated frequency, and performs a process of determining whether or not the radio wave interferes again. That is, the data reading apparatus 100 changes the designated frequency and repeats the determination process as to whether or not the radio wave interferes until a frequency at which radio wave interference with another data reading apparatus 100 does not occur is found. By this processing, the data reading apparatus 100 avoids radio wave interference with other data reading apparatuses 100. The frequency changing step (S113) will be described later.

  In the standby step (S105), the data reading apparatus 100 waits for execution of processing for a predetermined time. This processing is performed because a predetermined time is required for carrier sense, and even if a channel that is not used at the beginning (no radio wave interference occurs) is detected, the channel cannot be used immediately.

  In the second interference level detection step (S106), the second interference level detection unit 134 detects the second detection value that is the interference level of the designated frequency band and stores it in the storage device 984.

  In the second comparison step and the determination step (S107), the second comparison unit 136 compares the second threshold value set by the second interference level setting unit 132 and the second detection value detected by the second interference level detection unit 134. Then, the processing device 980 determines whether or not the second detection value is equal to or less than the second threshold value. If the second detection value is less than or equal to the second threshold (YES in S107), the data reading apparatus 100 performs a first interference level detection step (S108). On the other hand, when the second detection value is not equal to or smaller than the second threshold value (NO in S107), the data reading apparatus 100 proceeds to the frequency changing step (S113). That is, for example, when the second comparison unit 136 determines that the second detection value is equal to or smaller than the second threshold (YES in S107), the second determination unit 130 determines that the data reading device 100 and the data reading device 100 are integrated with the IC. It is determined that radio wave interference with the tag 200 does not occur. In this case, the determination unit 140 determines that the first comparison unit 126 determines that the first detection value is less than or equal to the first threshold value, and the second comparison unit 136 determines that the second detection value is less than or equal to the second threshold value. Therefore, the processing device 980 determines that the radio wave does not interfere. Then, the data reading apparatus 100 proceeds to a first interference level detection step (S108) which is the next process. On the other hand, for example, when the second comparison unit 136 determines that the second detection value is not equal to or less than the second threshold (NO in S107), the second determination unit 130 detects the radio wave between the data reading device 100 and the IC tag 200. It is determined that interference occurs. In this case, the determination unit 140 determines that the radio wave interferes with the processing device 980. Then, the data reading device 100 proceeds to the frequency changing step (S113), changes the designated frequency, and performs again from the determination process whether or not the radio wave interferes with another data reading device 100. That is, the data reading device 100 changes the designated frequency until a frequency at which no radio wave interference with another data reading device 100 and no radio wave interference between the data reading device 100 and the IC tag 200 is found. The process for determining whether or not radio waves interfere is repeated. By this processing, the data reading device 100 avoids radio wave interference between other data reading devices 100 and radio wave interference between the data reading device 100 and the IC tag 200.

  In the first interference level detection step (S108), as in the first interference level detection step (S103), the first interference level detection unit 124 is the first detection value that is the interference level of the designated frequency designated by the frequency designation unit 110. Is stored in the storage device 984.

In the first comparison step (S109), as in the first comparison step (S104), the first comparison unit 126 detects the first threshold set by the first interference level setting unit 122 and the first interference level detection unit 124. The first detection value is compared, and the processing device 980 determines whether or not the first detection value is less than or equal to the first threshold value. If the first detection value is less than or equal to the first threshold (YES in S109), the data reading apparatus 100 proceeds to the command issuing step (S110). On the other hand, when the first detection value is not equal to or less than the first threshold (NO in S109), the data reading apparatus 100 proceeds to the frequency changing step (S113).
Similar to the standby step (S105), this processing requires a predetermined time for carrier sense, and even if a channel that is not used at the beginning (no radio wave interference) is detected, that channel is used immediately. Do it because you can't. That is, after a predetermined time has elapsed, the data reading apparatus 100 confirms again that the channel assigned to the designated frequency is not being used.

  In the command issuing step (S110), the determination unit 140 determines that the radio wave does not interfere, and if it is confirmed that the channel assigned to the designated frequency is not used even after a predetermined time has elapsed, transmission is performed. Unit 150 transmits the command to IC tag 200.

In the response receiving step (S111), the receiving unit 160 receives a response to the command transmitted by the transmitting unit 150 from the IC tag.
Here, the IC tag receiving unit 210 of the IC tag 200 receives the command transmitted by the transmitting unit 150. Then, processing is performed based on the command received by the IC tag receiving unit 210, and the processing result is transmitted by the communication device 986. The receiving unit 160 receives this response.

  In the end determination step (S112), the data reading apparatus 100 issues a command again or ends the process depending on whether there is a response from the IC tag 200 or whether a predetermined time has elapsed. Determine.

  In the frequency changing step (S113), the frequency specifying unit 110 changes the specified frequency. In this case, the frequency designation unit 110 clears the designated frequency, and performs the processing from the frequency designation step (S102) again.

  Next, an example of the operation of the RFID system 300 including the data reading device 100 according to the first embodiment and the IC tag 200 will be described based on FIGS. 3, 4, and 5.

First, it is assumed that the interference level of the channel assigned to each frequency is in the state of interference level (a) 410 shown in FIG. First, in the first interference level setting step and the second interference level setting step (S101), it is assumed that the first interference level setting unit 122 sets the first threshold value to the first interference level shown in FIGS. In addition, it is assumed that the second interference level setting unit 132 sets the second threshold value to the second interference level shown in FIGS.
Next, in the frequency designation step (S102), it is assumed that the frequency designation unit 110 designates channel 1. Next, in the first interference level detection step (S103), the first interference level detection unit 124 detects the interference level of the channel 1. In the first comparison step (S104), the first comparison unit 126 determines that the first detection value is not less than or equal to the first threshold (NO in S104). That is, the first comparison unit 126 determines that another data reading device 100 is using the channel 1. That is, when the channel 1 is used, the first comparison unit 126 determines that radio wave interference occurs with other data readers 100 in the vicinity.
Therefore, next, in the frequency changing step (S113), the frequency specifying unit 110 clears the channel 1 that is the specified frequency. Next, in the frequency designation step (S102), the frequency designation unit 110 designates the designated frequency again. Here, it is assumed that the frequency specifying unit 110 has set channel 2. Then, the data reading apparatus 100 performs the first interference level detection step (S103) and the first comparison step (S104) again. In the first comparison step (S104), the first comparison unit 126 determines that another data reader 100 in the vicinity is using the channel 2.
Therefore, the data reading apparatus 100 performs a frequency changing step (S113) and a frequency specifying step (S102). In the frequency designation step (S102), it is assumed that the frequency designation unit 110 designates channel 3 as the designated frequency. Then, the data reading apparatus 100 performs the first interference level detection step (S103) and the first comparison step (S104) again. In the first comparison step (S104), the first comparison unit 126 determines that the first detection value is not more than the first threshold (YES in S104). That is, the first comparison unit 126 determines that another data reading device 100 in the vicinity does not use the channel 3.

  Therefore, next, in a standby step (S105), the data reading apparatus 100 waits for execution of a predetermined time process. Next, in the second interference level detection step (S106), the second interference level detection unit 134 detects the interference level of the frequency band including the channel 3 that is the designated frequency. That is, here, the second interference level detection unit 134 detects the interference level from channel 1 to channel 9 which is a frequency band in which channel 3 is included. Here, it is assumed that the interference level from channel 1 to channel 9 is in the state of interference level (a) 410 shown in FIG. In the second comparison step (S107), since the channel 5 is larger than the second threshold value, the second comparison unit 136 determines that the second detection value is not less than or equal to the second threshold value (NO in S107). In other words, the second comparison unit 136 determines that the use of the channel 3 affects the IC tag 200 in communication with the other data reading device 100. That is, the second comparison unit 136 determines that radio wave interference occurs with the IC tag 200.

  Therefore, next, in the frequency changing step (S113), the frequency specifying unit 110 clears the channel 3 that is the specified frequency. Next, in the frequency designation step (S102), the frequency designation unit 110 designates the designated frequency again. Then, the data reading apparatus 100 performs the first interference level detection step (S103) and the first comparison step (S104) again. As a result of repeating the above processing (S113 to S104), in the first comparison step (S104), the first comparison unit 126 determines that the other data reading device 100 in the vicinity does not use the channel 6.

  Next, in the standby step (S105), the data reading apparatus 100 waits for execution of processing for a predetermined time. In the second interference level detection step (S106), the second interference level detection unit 134 detects the interference levels from channel 1 to channel 9. Here, it is assumed that the interference levels from channel 1 to channel 9 are in the state of interference level (b) 420 shown in FIG. In the second comparison step (S107), the second comparison unit 136 determines that the second detection value is less than or equal to the second threshold because all the interference levels from channel 1 to channel 9 are less than or equal to the second threshold (YES in S107). ). That is, the second comparison unit 136 determines that the channel 6 is not used to affect the IC tag 200 in communication with the other data reading apparatus 100. That is, the second comparison unit 136 determines that there is no radio wave interference with the IC tag 200. Therefore, the determination unit 140 determines that radio waves do not interfere.

  Therefore, next, the data reading device 100 performs the first interference level detection step (S108) and the first comparison step (S109), and the other data reading devices in the vicinity of the channel 6 even after a predetermined time has elapsed. Make sure 100 is not using channel 6. That is, the data reading apparatus 100 confirms that no radio wave interference occurs with other data reading apparatuses 100 in the vicinity even if the channel 6 is used after a predetermined time has elapsed.

  When confirmation is obtained (YES in S109), the data reading apparatus 100 performs a command issuing step (S110), a response receiving step (S111), and an end determination step (S112).

According to the data reading apparatus 100 and the RFID system 300 according to the first embodiment, even when a plurality of data reading apparatuses 100 are arranged in the vicinity, radio wave interference between the data reading apparatus 100 and another data reading apparatus 100. It is possible to prevent radio wave interference between the data reading apparatus 100 and the IC tag 200.
Therefore, according to the data reading apparatus 100 and the RFID system 300 according to the first embodiment, the data reading apparatus 100 can perform stable communication with the IC tag 200.

  In the above, when the second comparison unit 136 determines in the second comparison step (S107) that the second detection value is not less than or equal to the second threshold value (NO in S107), the data reading apparatus 100 performs the frequency change step (S113). The frequency designation unit 110 has changed the designated frequency. However, the present invention is not limited to this, and the data reading apparatus 100 may proceed to the second interference level detection step (S106) after waiting for a predetermined time.

  Further, the second interference level detection unit 134 detects the interference level of each channel of the plurality of channels allocated to the designated frequency band as the second detection value, and stores it in the storage device 984. The second comparison unit 136 The second threshold value is compared with each second detection value for each channel detected by the second interference level detection unit 134, and it is determined whether each second detection value for each channel is equal to or less than the second threshold value. 140, the first comparison unit 126 determines that the first detection value is less than or equal to the first threshold, and the second comparison unit 136 determines that all the second detection values for each channel are less than or equal to the second threshold. In this case, it may be determined that radio waves do not interfere.

Furthermore, the first interference level setting unit 122 sets the first threshold based on the magnitude of the output for transmitting the radio wave of the designated frequency, and the second interference level setting unit 132 is the magnitude of the output for sending the radio wave of the designated frequency. The second threshold value may be set based on this.
The first interference level setting unit 122 and the second interference level setting unit 132 may change the first threshold value and the second threshold value, respectively, when the magnitude of the output for transmitting the radio wave of the designated frequency is changed. I do not care.
When the output for transmitting the radio waves of the specified frequency is low, radio wave interference between the other data reader 100 and the IC tag 200 is less likely to occur than when the output for transmitting the radio waves of the specified frequency is high. Therefore, the first interference level setting unit 122 and the second interference level setting unit 132 set the first threshold value and the second threshold value based on the magnitude of the output for transmitting the radio wave of the specified frequency. Launching can be efficiently performed, and wireless communication between the data reader 100 and the IC tag 200 can be efficiently performed.

The RFID system according to the first embodiment is summarized as follows: a memory that holds data, a command analysis unit that demodulates a command given from the outside and analyzes the command, a memory control unit that reads or writes the memory, and the memory An IC tag having a command execution unit that performs processing based on the read data and an analysis result in the command analysis unit, and a transmission unit that transmits the data read from the memory;
An RFID system including the IC tag and a data reading device that performs non-contact data communication, wherein the RFID system includes the following means.
The data reader includes: (a) a transmitter that transmits a command or unmodulated wave to the IC tag; (b) a receiver that receives a response from the IC tag; and (c) a frequency interference level to be used. 1 interference level setting means (d) second interference level setting means (e) for setting an interference level of a frequency band which is larger than the interference level set by the first interference level setting means and which is assigned to the RFID system including the frequency to be used. ) First interference level detection means for detecting the interference level of the frequency to be used (f) Second interference level detection means for detecting the interference level of the frequency band assigned to the RFID system including the frequency to be used (g) The interference level detected by the first interference level detection means is equal to or lower than the interference level set by the first interference level setting means, and the second interference Interference level bell detection means has detected that, when the interference level is below that set by the second interference level setting means includes a control unit which controls transmission of commands or unmodulated wave from the transmitting unit.

  In addition, the data reading device includes: (a) a transmission output control unit that makes a transmission output variable; (b) first interference level setting means that can change an interference level of a frequency to be used by transmission output; and (c) transmission output. And second interference level setting means for setting the interference level of the frequency band or the notification dedicated channel.

Embodiment 2. FIG.
Next, a second embodiment will be described. In the second embodiment, when a communication wave that is a communication radio wave for sending a command or the like to the IC tag 200 is transmitted, a notification channel in which the notification wave that is a notification radio wave is assigned to a predetermined frequency A data reading apparatus 100 that transmits data to and an RFID system 300 including the data reading apparatus 100 will be described.

  First, the function of the RFID system 300 including the data reading device 100 and the IC tag 200 according to the second embodiment will be described with reference to FIG. FIG. 6 is a functional block diagram illustrating functions of the RFID system 300 including the data reading apparatus 100 and the IC tag 200 according to the second embodiment. Here, only functions different from those of the RFID system 300 according to the first embodiment will be described.

The data reading apparatus 100 according to the second embodiment includes a notification channel determination unit 170 instead of the second determination unit 130.
The notification channel determination unit 170 performs coarse-accuracy carrier sense on the notification channel. The reason for performing coarse carrier sense is, for example, to determine whether or not radio wave interference occurs between the data reader 100 and the IC tag 200. That is, the notification channel determination unit 170 determines whether or not the IC tag 200 in communication with another data reading apparatus 100 is affected by performing carrier sense on the notification channel through which the notification wave is transmitted. . The notification channel determination unit 170 includes a notification channel interference level setting unit 172, a notification channel interference level detection unit 174, and a notification channel comparison unit 176.
The notification channel interference level setting unit 172 sets a notification channel threshold that is a threshold of the notification channel interference level and stores the notification channel threshold in the storage device 984. Here, normally, the first determination unit 120 performs high-accuracy carrier sense, and the notification channel determination unit 170 performs coarse-accuracy carrier sense. Therefore, the notification channel threshold is larger than the first threshold.
The notification channel interference level detection unit 174 detects a notification channel detection value that is an interference level of the notification channel, and stores it in the storage device 984.
The notification channel comparison unit 176 compares the notification channel threshold set by the notification channel interference level setting unit 172 with the notification channel detection value detected by the notification channel interference level detection unit 174, and the notification channel detection value is equal to or less than the notification channel threshold. The processing device 980 determines whether or not there is any.
That is, for example, when the notification channel comparison unit 176 determines that the notification channel detection value is equal to or less than the notification channel threshold, the notification channel determination unit 170 generates radio wave interference between the data reader 100 and the IC tag 200. Judge that not.

  The determination unit 140 determines that the first comparison unit 126 determines that the first detection value is less than or equal to the first threshold value, and the notification channel comparison unit 176 determines that the notification channel detection value is less than or equal to the notification channel threshold value. The processing device 980 determines that the radio wave does not interfere.

  In addition to the function of the first embodiment, the transmission unit 150 transmits a communication wave to the IC tag 200 when transmitting a communication wave that is a communication radio wave such as a command to the IC tag 200. Is transmitted to a notification channel assigned to a predetermined frequency. Here, the notification wave is an unmodulated wave or the like.

  Next, an operation of the RFID system 300 including the data reading apparatus 100 and the IC tag 200 according to the second embodiment will be described with reference to FIG. FIG. 7 is a flowchart illustrating an interference determination method that is an operation of the RFID system 300 including the data reading apparatus 100 and the IC tag 200 according to the second embodiment. Here, only operations different from those of the RFID system 300 according to the first embodiment will be described.

  In the first interference level setting step and the notification channel interference level setting step (S201), the first interference level setting unit 122 is the first interference level threshold value specified by the frequency specifying unit 110 as in (S101). A threshold value is set and stored in the storage device 984. Also, the notification channel interference level setting unit 172 sets a notification channel threshold that is a threshold of the notification channel interference level, and stores the notification channel threshold in the storage device 984. For example, the first interference level setting step and the notification channel interference level setting step may be performed only when the data reader 100 is activated, or may be performed after the frequency designation step (S202).

  (S202) to (S205) are the same as (S102) to (S105), respectively.

  In the notification channel interference level detection step (S206), the notification channel interference level detection unit 174 detects the notification channel detection value that is the interference level of the notification channel and stores it in the storage device 984.

  In the notification channel comparison step and the determination step (S207), the notification channel comparison unit 176 compares the notification channel threshold set by the notification channel interference level setting unit 172 with the notification channel detection value detected by the notification channel interference level detection unit 174. The processing device 980 determines whether the notification channel detection value is equal to or less than the notification channel threshold value. When the notification channel detection value is equal to or less than the notification channel threshold value (YES in S207), a first interference level detection step (S208) is performed. On the other hand, if the notification channel detection value is not less than or equal to the notification channel threshold (NO in S207), the process proceeds to the frequency change step (S213). That is, for example, when the notification channel comparison unit 176 determines that the notification channel detection value is equal to or less than the notification channel threshold (YES in S207), the notification channel determination unit 170 determines whether the notification channel comparison unit 176 determines whether the notification channel detection value is equal to or less than the notification channel threshold. It is determined that radio wave interference does not occur. In this case, the determination unit 140 determines that the first comparison unit 126 determines that the first detection value is less than or equal to the first threshold, and the notification channel comparison unit 176 determines that the notification channel detection value is less than or equal to the notification channel threshold. Therefore, the processing device 980 determines that the radio wave does not interfere. Then, the data reading apparatus 100 proceeds to a first interference level detection step (S208) which is the next process. On the other hand, the notification channel determination unit 170, for example, when the notification channel comparison unit 176 determines that the notification channel detection value is not equal to or less than the notification channel threshold (NO in S207), the radio wave between the data reader 100 and the IC tag 200 It is determined that interference occurs. In this case, the determination unit 140 determines that the radio wave interferes with the processing device 980. Then, the data reading apparatus 100 proceeds to the frequency changing step (S213), changes the designated frequency, and performs again from the determination process whether or not radio waves interfere with other data reading apparatuses 100. In other words, whether the radio wave interferes by changing the designated frequency until a frequency that does not cause radio wave interference with another data reading apparatus 100 and a radio wave interference between the data reading apparatus 100 and the IC tag 200 is found. Repeat the determination process. By this process, radio wave interference between the other data reading device 100 and radio wave interference between the data reading device 100 and the IC tag 200 are avoided.

  (S208) to (S209) are the same as (S108) to (S109), respectively.

  In the command issuance step (S210), the transmission unit 150 transmits a command to the IC tag 200, and transmits a notification wave to the other data reader 100 to notify that the radio wave is transmitted to the IC tag 200 to the notification channel. Send.

  In the response reception step (S211), the reception unit 160 receives a response to the command transmitted by the transmission unit 150 from the IC tag. And the transmission part 150 stops transmission of a notification wave.

  (S212) to (S213) are the same as (S112) to (S113), respectively.

  According to the data reader 100 and the RFID system 300 according to the second embodiment, by measuring the interference level of the notification channel, the interference level of the frequency band assigned to the RFID system 300 including the specified frequency is measured. Become equivalent. Therefore, according to the data reader 100 and the RFID system 300 according to the second embodiment, data is measured by measuring the interference level of only the notification channel without measuring all the interference levels from the channel 1 to the channel 9. It is possible to determine whether or not radio waves between the reading device 100 and the IC tag 200 interfere. Therefore, according to the data reading apparatus 100 and the RFID system 300 according to the second embodiment, it is possible to reduce the time required for carrier sense.

Here, the first interference level setting unit 122 sets the first threshold value based on the magnitude of the output for transmitting the radio wave of the designated frequency, and the notification channel interference level setting unit 172 outputs the output for transmitting the radio wave of the designated frequency. The notification channel threshold may be set based on the size.
The first interference level setting unit 122 and the notification channel interference level setting unit 172 may change the first threshold value and the notification channel threshold value, respectively, when the magnitude of the output for transmitting the radio wave of the specified frequency is changed. I do not care.
When the output for transmitting the radio waves of the specified frequency is low, radio wave interference between the other data reader 100 and the IC tag 200 is less likely to occur than when the output for transmitting the radio waves of the specified frequency is high. Therefore, the first interference level setting unit 122 and the notification channel interference level setting unit 172 set the first threshold value and the notification channel threshold value based on the magnitude of the output for transmitting the radio wave of the specified frequency. Launching can be efficiently performed, and wireless communication between the data reader 100 and the IC tag 200 can be efficiently performed.

The RFID system according to the second embodiment is summarized as follows: a memory that holds data, a command analysis unit that demodulates a command given from the outside and analyzes the command, a memory control unit that reads or writes the memory, and the memory An IC tag having a command execution unit that performs processing based on the read data and an analysis result in the command analysis unit, and a transmission unit that transmits the data read from the memory;
An RFID system including the IC tag and a data reading device that performs non-contact data communication, wherein the RFID system includes the following means.
The data reading device uses (a) a first transmission unit that transmits a command or an unmodulated wave to the IC tag, and (b) uses a dedicated notification channel indicating that a radio wave is transmitted. A second transmission unit that transmits a response (c) a reception unit that receives a response from the IC tag (d) a first interference level setting unit that sets an interference level of a frequency to be used (e) a first interference level setting unit Second interference level setting means for setting the interference level of the dedicated notification channel that is greater than the interference level to be set (f) First interference level detection means for detecting the interference level of the frequency to be used (g) Interference level of the dedicated notification channel Second interference level detecting means for detecting (h) the interference level detected by the first interference level detecting means is less than or equal to the interference level set by the first interference level setting means In addition, when the interference level detected by the second interference level detection unit is equal to or lower than the interference level set by the second interference level setting unit, a command or an unmodulated wave is transmitted from the first transmission unit or the second transmission unit. A control unit that performs transmission control is provided.

  In addition, the data reading device includes: (a) a transmission output control unit that makes a transmission output variable; (b) first interference level setting means that can change an interference level of a frequency to be used by transmission output; and (c) transmission output. And second interference level setting means for setting the interference level of the frequency band or the notification dedicated channel.

Embodiment 3 FIG.
Next, Embodiment 3 will be described. In the third embodiment, the IC tag 200 and a data reading unit that transmits radio waves to the IC tag 200 through a transmission-dedicated channel having a predetermined frequency and receives radio waves from the IC tag 200 through a reception-dedicated channel having a frequency different from the transmission-dedicated channel. An interference determination device that determines whether a radio wave used in an RFID system 300 including the device 100 interferes with a predetermined radio wave will be described.

  First, the function of the RFID system 300 including the data reading device 100 and the IC tag 200 according to the third embodiment will be described with reference to FIG. FIG. 8 is a functional block diagram illustrating functions of the RFID system 300 including the data reading device 100 and the IC tag 200 according to the third embodiment. Here, only functions different from those of the RFID system 300 according to the first embodiment will be described.

The data reading apparatus 100 according to the third embodiment does not include the first determination unit. In the third embodiment, the transmission unit 150 is a transmission channel use transmission unit that transmits radio waves to the IC tag 200 through a transmission channel having a predetermined frequency. The receiving unit 160 is a receiving channel use receiving unit that receives radio waves from the IC tag 200 through a receiving channel with a frequency different from that of the transmitting channel. That is, the frequency of the radio wave emitted from the data reading device 100 and the frequency of the reflected wave emitted from the IC tag 200 are separated .
Therefore, the data reading apparatus 100 according to the third embodiment does not need to include the first determination unit.

  Next, the operation of the RFID system 300 including the data reading apparatus 100 and the IC tag 200 according to the third embodiment will be described with reference to FIG. FIG. 9 is a flowchart illustrating an interference determination method that is an operation of the RFID system 300 including the data reading apparatus 100 and the IC tag 200 according to the third embodiment. Here, only operations different from those of the RFID system 300 according to the first embodiment will be described.

  In the second interference level setting step (S301), the second interference level setting unit 132 is an interference level threshold value of a designated frequency band that is a frequency band including designated frequencies of a plurality of frequency bands assigned to the RFID system 300. A second threshold is set and stored in the storage device 984. There is no need to set the first threshold. Others are the same as (S101).

  (S302) is the same as (S102).

Further, (S303) and (S304) are the same as (S106) and (S107), respectively. That is, in the second interference level detection step (S303), the second interference level detection unit 134 detects the second detection value that is the interference level of the designated frequency band and stores it in the storage device 984. In the second comparison step and the determination step (S304), the second comparison unit 136 includes the second threshold value set by the second interference level setting unit 132 and the second detection value detected by the second interference level detection unit 134. And the processing device 980 determines whether or not the second detection value is equal to or smaller than the second threshold value. When the second detection value is equal to or smaller than the second threshold value (YES in S304), the data reading apparatus 100 performs a standby step (S305). On the other hand, when the second detection value is not equal to or less than the second threshold value (NO in S304), the data reading apparatus 100 proceeds to the frequency changing step (S311). That is, for example, when the second comparison unit 136 determines that the second detection value is equal to or less than the second threshold (YES in S304), the second determination unit 130 determines whether the second reader 130 is between the data reader 100 and the IC tag 200. It is determined that radio wave interference does not occur. In this case, the determination unit 140 determines that the radio wave does not interfere with the processing device 980 because the second comparison unit 136 determines that the second detection value is equal to or less than the second threshold value. Then, the data reading apparatus 100 proceeds to a standby step (S305) which is the next process. On the other hand, for example, when the second comparison unit 136 determines that the second detection value is not equal to or less than the second threshold (NO in S304), the second determination unit 130 detects the radio wave between the data reading device 100 and the IC tag 200. It is determined that interference occurs. In this case, the determination unit 140 determines that the radio wave interferes with the processing device 980 because the second comparison unit 136 determines that the second detection value is not equal to or less than the second threshold value. Then, the data reading device 100 proceeds to the frequency changing step (S311), changes the designated frequency, and performs again from the determination process whether or not the radio wave interferes with another data reading device 100. That is, the data reading device 100 changes the designated frequency and repeats the determination process of whether or not the radio wave interferes until a frequency at which radio wave interference between the data reading device 100 and the IC tag 200 does not occur is found. With this process, the data reading apparatus 100 avoids radio wave interference between the data reading apparatus 100 and the IC tag 200 .

  (S305) is the same as (S105).

  In the second interference level detection step (S306), as in the second interference level detection step (S303), the second interference level detection unit 134 detects the second detection value that is the interference level of the designated frequency band, and the storage device 984. To remember. Further, in the second comparison step and determination step (S307), as in the second comparison step and determination step (S304), the second comparison unit 136 sets the second threshold value set by the second interference level setting unit 132 and the second threshold value. The second detection value detected by the interference level detection unit 134 is compared, and the processing device 980 determines whether the second detection value is equal to or less than the second threshold value. When the second detection value is equal to or smaller than the second threshold value (YES in S307), the data reading apparatus 100 proceeds to the command issuing step (S308). On the other hand, when the second detection value is not equal to or less than the second threshold value (NO in S307), the data reading apparatus 100 proceeds to the frequency changing step (S311). That is, for example, when the second comparison unit 136 determines that the second detection value is equal to or smaller than the second threshold (YES in S307), the second determination unit 130 determines that the data reading device 100 and the data reading device 100 are integrated with the IC. It is determined that radio wave interference with the tag 200 does not occur.

  (S308) to (S311) are the same as (S110) to (S113), respectively.

  In the third embodiment, the data reader 100 transmits radio waves to the IC tag 200 through a transmission-dedicated channel having a predetermined frequency, and receives radio waves from the IC tag 200 through a reception-dedicated channel having a frequency different from that of the transmission-dedicated channel. That is, in the third embodiment, the frequency of the radio wave emitted from the data reading device 100 and the frequency of the reflected wave emitted from the IC tag 200 are separated. Therefore, it is possible to prevent radio wave interference between the data reading apparatus 100 and another data reading apparatus 100. Therefore, according to the data reading device 100 and the RFID system 300 according to the third embodiment, the second determination unit confirms that interference between the data reading device 100 and the IC tag 200 does not occur, so that the data The reading device 100 can perform stable communication with the IC tag 200.

  In the above description, in the second comparison step (S304, S307), when the second comparison unit 136 determines that the second detection value is not less than or equal to the second threshold value (NO in S304, S307), the data reader 100 changes the frequency. Proceeding to step (S311), the frequency specifying unit 110 changes the specified frequency. However, the present invention is not limited to this, and the data reader 100 may proceed to the second interference level detection step (S303) after waiting for a predetermined time.

Further, the second interference level setting unit 132 may set the second threshold based on the magnitude of the output for transmitting the radio wave of the designated frequency. The second interference level setting unit 132 may change the second threshold when the magnitude of the output for transmitting the radio wave of the designated frequency is changed.
When the output for transmitting the radio waves of the specified frequency is low, radio wave interference between the other data reader 100 and the IC tag 200 is less likely to occur than when the output for transmitting the radio waves of the specified frequency is high. Therefore, since the second interference level setting unit 132 sets the second threshold based on the magnitude of the output for transmitting the radio wave of the designated frequency, the data reader 100 can efficiently emit the radio wave, and the data reader 100 And the IC tag 200 can be efficiently communicated with each other.

The RFID system according to the third embodiment is summarized as follows: a memory that holds data, a command analysis unit that demodulates a command given from the outside and analyzes the command, a memory control unit that reads or writes the memory, and the memory An IC tag having a command execution unit that performs processing based on the read data and an analysis result in the command analysis unit, a transmission unit that transmits data read from the memory, and the IC tag and non-contact data An RFID system having a data reader for communication,
The RFID system includes the following means for transmitting a command to the IC tag using a frequency dedicated for transmission and receiving a response from the IC tag using a frequency dedicated for reception.
The data reader is assigned to an RFID system including (a) a transmitter that transmits a command or unmodulated wave to the IC tag, (b) a receiver that receives a response from the IC tag, and (c) a frequency to be used. Second interference level setting means (d) for setting the interference level of the different frequency band (d) second interference level detection means (e) for detecting the interference level of the frequency band assigned to the RFID system including the frequency to be used When the interference level detected by the interference level detection unit is equal to or lower than the interference level set by the second interference level setting unit, the control unit includes a control unit that performs transmission control of a command or an unmodulated wave from the transmission unit.

  In addition, the data reading device includes (a) a transmission output control unit that makes the transmission output variable (b) second interference level setting means that sets an interference level of a frequency band or a notification-dedicated channel by transmission output.

Embodiment 4 FIG.
Next, a fourth embodiment will be described. In the fourth embodiment, unlike in the first embodiment, it is determined whether or not radio waves of a predetermined frequency around the designated frequency interfere. As a result, the data reading apparatus 100 and the data reading apparatus 100 can prevent the interference of radio waves between the data reading apparatus 100 and the other data reading apparatus 100 and the interference of radio waves between the data reading apparatus 100 and the IC tag 200. An RFID system 300 including the above will be described.

  First, the function of the RFID system 300 including the data reading apparatus 100 and the IC tag 200 according to the fourth embodiment will be described with reference to FIG. FIG. 10 is a functional block diagram illustrating functions of the RFID system 300 including the data reading device 100 and the IC tag 200 according to the fourth embodiment. Here, only functions different from those of the RFID system 300 according to the first embodiment will be described.

The data reading apparatus 100 according to the fourth embodiment includes a peripheral frequency determination unit 180 instead of the second determination unit 130.
The peripheral frequency determination unit 180 performs coarse carrier sense on a peripheral frequency that is a predetermined frequency around (near) the frequency to be used. The reason why the coarse carrier sense is performed is, for example, to determine whether or not radio wave interference occurs between the data reader 100 and the IC tag 200 with which the other data reader 100 is communicating. Here, the accuracy of carrier sense will be described later. The peripheral frequency determination unit 180 includes a peripheral frequency interference level setting unit 182, a peripheral frequency interference level detection unit 184, and a peripheral frequency comparison unit 186.
The peripheral frequency interference level setting unit 182 sets a peripheral frequency threshold that is a threshold of the interference level of the peripheral frequency and stores it in the storage device 984. The peripheral frequency interference level setting unit 182 sets each of a plurality of predetermined frequencies within a predetermined range from the specified frequency as the peripheral frequency, and sets a larger value for the peripheral frequency threshold as the peripheral frequency is farther from the specified frequency. It doesn't matter.
The peripheral frequency interference level detection unit 184 detects a peripheral frequency detection value that is an interference level of the peripheral frequency and stores it in the storage device 984. When there are a plurality of peripheral frequencies, the peripheral frequency interference level detection unit 184 detects a peripheral frequency detection value of each peripheral frequency.
The peripheral frequency comparison unit 186 compares the peripheral frequency threshold set by the peripheral frequency interference level setting unit 182 with the peripheral frequency detection value detected by the peripheral frequency interference level detection unit 184, and the peripheral frequency detection value is equal to or less than the peripheral frequency threshold. The processing device 980 determines whether or not there is any. When there are a plurality of peripheral frequencies, the peripheral frequency comparison unit 186 compares the peripheral frequency threshold value with the peripheral frequency detection value for each peripheral frequency, and determines whether the peripheral frequency detection value is equal to or less than the peripheral frequency threshold value. To do.
In other words, for example, when the peripheral frequency comparison unit 186 determines that the peripheral frequency detection value is equal to or lower than the peripheral frequency threshold for all peripheral frequencies, the peripheral frequency determination unit 180 and the other data reading units It is determined that radio wave interference between the device 100 and the IC tag 200 in communication does not occur.

  The determination unit 140 determines that the first comparison unit 126 determines that the first detection value is equal to or lower than the first threshold value, and the peripheral frequency comparison unit 186 determines that the peripheral frequency detection value is equal to or lower than the peripheral frequency threshold value. The processing device 980 determines that the radio wave does not interfere. When there are a plurality of peripheral frequencies, the determination unit 140 determines that the first comparison unit 126 determines that the first detection value is less than or equal to the first threshold value, and the peripheral frequency comparison unit 186 determines for all the peripheral frequencies. When it is determined that the detected peripheral frequency value is equal to or lower than the peripheral frequency threshold value, it is determined that the radio wave does not interfere.

  Next, the interference level of the channel assigned to each frequency at a certain time will be described based on FIGS. FIG. 11 is a diagram showing the interference level (c) 430 of the channel assigned to each frequency at a certain time. FIG. 12 is a diagram showing an interference level (d) 440 of a channel assigned to each frequency at a certain time. 11 and 12, “CH-1” indicates channel 1, “CH-2” indicates channel 2, and “CH−” is similarly read as channel. Here, it is assumed that each frequency in a certain frequency band assigned to the RFID system 300 is assigned to channel 1 to channel 9. In each of the interference level (c) 430 and the interference level (d) 440, the first interference level is the first threshold, the (N-1) interference level is the (N-1) threshold, and the (N-2) interference level is (N -2) A threshold value is set. Here, the (N-1) threshold value and the (N-2) threshold value are examples of the peripheral frequency threshold value. Further, (N-1) interference level is an interference level of a predetermined frequency closest to the use frequency (adjacent channel), and (N-2) interference level is second closest to the use frequency (next adjacent channel). It is an interference level of a predetermined frequency.

  At interference level (c) 430, channel 3, channel 6, and channel 8 are below the first threshold. Further, at the interference level (c) 430, the channel 7 is equal to or less than the (N-1) threshold. Further, in the interference level (c) 430, the channel 2 and the channel 4 are equal to or smaller than the (N-2) threshold value. In addition, at interference level (c) 430, channel 1, channel 5, and channel 9 are larger than the (N-2) threshold.

  At interference level (d) 440, channel 3, channel 6, and channel 8 are below the first threshold. Further, at interference level (d) 440, channel 2, channel 4, and channel 7 are equal to or lower than the (N-1) threshold. Further, at interference level (d) 440, channel 1 and channel 5 are equal to or lower than the (N-2) threshold. Also, at interference level (d) 440, channel 9 is greater than the (N-2) threshold.

FIG. 13 shows how much intensity influences communication as noise when another data reader 100 emits radio waves at different frequencies while the data reader 100 and the IC tag 200 are communicating at the frequency N. Represents. The vertical axis indicates the noise intensity (C / I), and the horizontal axis indicates the frequency. In the vicinity of the frequency (N) to be used, the IC tag 200 is very sensitive to noise. However, it shows that it becomes more resistant to noise as it goes away from the frequency to be used. Based on the characteristics of the IC tag 200, the (N-1) interference level that is the interference level in the adjacent channel and the (N-2) interference level that is the interference level in the next adjacent channel are determined.
That is, the peripheral frequency interference level setting unit 182 sets the peripheral frequency threshold based on the characteristics of the IC tag 200 described above. For this reason, the peripheral frequency threshold is larger than the first threshold.

  Next, the operation of the RFID system 300 including the data reading device 100 and the IC tag 200 according to the fourth embodiment will be described with reference to FIG. FIG. 14 is a flowchart illustrating an interference determination method that is an operation of the RFID system 300 including the data reading apparatus 100 and the IC tag 200 according to the fourth embodiment. Here, only operations different from those of the RFID system 300 according to the first embodiment will be described.

  In the first interference level setting step and the peripheral frequency interference level setting step (S401), the first interference level setting unit 122 is the first interference level threshold value specified by the frequency specifying unit 110 as in (S101). A threshold value is set and stored in the storage device 984. Also, the peripheral frequency interference level setting unit 182 sets a peripheral frequency threshold value that is a threshold value of the interference level of the peripheral frequency, and stores it in the storage device 984. The peripheral frequency interference level setting unit 182 sets a peripheral frequency threshold for each channel that is a predetermined frequency in the peripheral frequency range. The range of the peripheral frequency represents how many channels away from the designated channel perform carrier sense. For example, the first interference level setting step and the peripheral frequency interference level setting step may be performed only when the data reader 100 is activated, or may be performed after the frequency designation step (S402).

  (S402) to (S405) are the same as (S102) to (S105), respectively.

  In the level setting step (S406), the peripheral frequency determination unit 180 sets the peripheral frequency for performing carrier sense by the processing device 980. Here, when the designated channel is N, the range of the peripheral frequency is J, and the variable is i, the peripheral frequency determination unit 180 sets the channel of the peripheral frequency for performing carrier sensing to the N−J + i channel. The variable i has an initial value of 0, for example, a value in the range of 0 ≦ i ≦ 2J. That is, carrier sense is performed up to the channel separated from the J channel with the designated channel N as the center.

  In the peripheral frequency interference level detection step (S407), the peripheral frequency interference level detection unit 184 detects the peripheral frequency detection value that is the interference level of the peripheral frequency of the channel set in (S406) and stores it in the storage device 984.

  In the peripheral frequency comparison step and the determination step (S408), the peripheral frequency comparison unit 186 includes the peripheral frequency threshold set by the peripheral frequency interference level setting unit 182 and the peripheral frequency interference level detection unit 184 in the channel set in (S406). The processing device 980 determines whether or not the peripheral frequency detection value is equal to or lower than the peripheral frequency threshold value. When the detected peripheral frequency is equal to or lower than the peripheral frequency threshold (YES in S408), a level changing step (S409) is performed. On the other hand, if the detected peripheral frequency value is not less than or equal to the peripheral frequency threshold value (NO in S408), the process proceeds to the frequency changing step (S416). That is, for example, if the peripheral frequency comparison unit 186 determines that the peripheral frequency detection value is equal to or less than the peripheral frequency threshold (YES in S408), the peripheral frequency determination unit 180 performs data reading on the channel set in (S406). It is determined that radio wave interference between the device 100 and the IC tag 200 with which the other data reading device 100 is communicating does not occur. On the other hand, for example, when the peripheral frequency comparison unit 186 determines that the detected peripheral frequency value is not equal to or less than the peripheral frequency threshold value (NO in S408), the peripheral frequency determination unit 180 uses the data reading device in the channel set in (S406). 100 and other data reading devices 100 determine that radio wave interference occurs with the IC tag 200 in communication. In this case, the determination unit 140 determines that the radio wave interferes with the processing device 980. Then, the data reading apparatus 100 proceeds to the frequency changing step (S416), changes the designated frequency, and performs again from the determination process whether or not radio waves interfere with another data reading apparatus 100. In other words, the determination unit 140 determines that the peripheral frequency detection value detected by the peripheral frequency interference level detection unit 184 is one of the peripheral frequency thresholds set by the peripheral frequency interference level setting unit 182 in all measured peripheral frequency channels. If it exceeds, it is determined that the other data reader 100 in the vicinity gives interference to the IC tag in communication. Then, until the frequency at which radio wave interference with the other data reading device 100 and the radio wave interference between the data reading device 100 and the IC tag 200 do not occur is detected, the designated frequency is changed and the radio wave interferes. Repeat the determination process.

  In the level changing step (S409), the peripheral frequency determining unit 180 increases (increments) the variable i by one.

  In the level determination step and determination step (S410), the peripheral frequency determination unit 180 determines whether or not the variable i is larger than 2J by the processing device 980. That is, the peripheral frequency determination unit 180 determines whether carrier sense has been completed up to all channels separated by J channels with the designated channel N as the center. When the surrounding frequency determination unit 180 determines that the variable i is greater than 2J (YES in S410), the determination unit 140 determines that the first comparison unit 126 has the first detection value equal to or less than the first threshold value, and In all the channels in the set range, the peripheral frequency comparison unit 186 determines that the peripheral frequency detection value is equal to or less than the peripheral frequency threshold, and thus the processing device 980 determines that radio waves do not interfere. Then, the data reading apparatus 100 proceeds to a first interference level detection step (S411) which is the next process. On the other hand, when the peripheral frequency determination unit 180 determines that the variable i is 2J or less (NO in S410), the peripheral frequency determination unit 180 returns to (S406) and performs carrier sense for the next channel.

  That is, by the above processing, radio wave interference between the other data reading device 100 and radio wave interference between the data reading device 100 and the IC tag 200 are avoided.

  (S411) to (S416) are the same as (S108) to (S113), respectively.

Next, an example of the operation of the RFID system 300 including the data reading device 100 according to the fourth embodiment and the IC tag 200 will be described based on FIGS. 11, 12, and 14.

First, it is assumed that the interference level of the channel assigned to each frequency is in the state of interference level (c) 430 shown in FIG. First, in the first interference level setting step and the peripheral frequency interference level setting step (S401), it is assumed that the first interference level setting unit 122 sets the first threshold value to the first interference level shown in FIG. Also, the peripheral frequency interference level setting unit 182 sets the (N-1) threshold of the peripheral frequency threshold to the (N-1) interference level shown in FIGS. 11 and 12, and the (N-2) threshold of the peripheral frequency threshold. Is set to the (N-2) interference level shown in FIGS. That is, here, it is assumed that J = 2.
Next, in the frequency designation step (S402), it is assumed that the frequency designation unit 110 designates channel 1. Next, in the first interference level detection step (S403), the first interference level detection unit 124 detects the interference level of the channel 1. In the first comparison step (S404), the first comparison unit 126 determines that the first detection value is not less than or equal to the first threshold (NO in S104). That is, the first comparison unit 126 determines that another data reading device 100 is using the channel 1. That is, when the channel 1 is used, the first comparison unit 126 determines that radio wave interference occurs with other data readers 100 in the vicinity.
Therefore, next, in the frequency changing step (S416), the frequency specifying unit 110 clears the channel 1 that is the specified frequency. Next, in the frequency designation step (S402), the frequency designation unit 110 designates the designated frequency again. Here, it is assumed that the frequency specifying unit 110 has set channel 2. Then, the data reading apparatus 100 performs the first interference level detection step (S403) and the first comparison step (S404) again. In the first comparison step (S404), the first comparison unit 126 determines that another data reader 100 in the vicinity is using the channel 2.
Therefore, the data reading apparatus 100 performs a frequency changing step (S416) and a frequency specifying step (S402). In the frequency designation step (S402), it is assumed that the frequency designation unit 110 designates channel 3 as the designated frequency. Then, the data reading apparatus 100 performs the first interference level detection step (S403) and the first comparison step (S404) again. In the first comparison step (S404), the first comparison unit 126 determines that the first detection value is not more than the first threshold (YES in S104). That is, the first comparison unit 126 determines that another data reading device 100 in the vicinity does not use the channel 3.

  Therefore, next, in the standby step (S405), the data reading apparatus 100 waits for execution of a predetermined time process. Next, in the level setting step (S406), the peripheral frequency determination unit 180 sets the channel of the peripheral frequency to channel 1, which is the (N-2) level channel. This is because the designated channel is 3, the peripheral frequency range is J is 2, and i is the initial value 0, so N−J + i is 1. Next, in the peripheral frequency interference level detection step (S407), the peripheral frequency interference level detection unit 184 detects the interference level of the peripheral frequency of the channel set in (S406). That is, here, the peripheral frequency interference level detection unit 184 detects the interference level of the channel 1 set in (S406). Here, it is assumed that the interference levels from channel 1 to channel 9 are in the state of interference level (c) 430 shown in FIG. In the peripheral frequency comparison step and the determination step (S408), the peripheral frequency comparison unit 186 determines that the peripheral frequency detection value is not less than or equal to the peripheral frequency threshold value (NO in S408) because channel 1 is larger than the (N-2) threshold value. To do. That is, the peripheral frequency comparison unit 186 determines that the use of the channel 1 affects the IC tag 200 in communication with another data reading apparatus 100. That is, the peripheral frequency comparison unit 186 determines that radio wave interference occurs with the IC tag 200.

  Therefore, next, in the frequency changing step (S416), the frequency specifying unit 110 clears the channel 3 that is the specified frequency. Next, in the frequency designation step (S402), the frequency designation unit 110 designates the designated frequency again. Then, the data reading apparatus 100 performs the first interference level detection step (S403) and the first comparison step (S404) again. As a result of repeating the above processing (S416 to S404), in the first comparison step (S404), the first comparison unit 126 determines that the other data reading device 100 in the vicinity does not use the channel 6.

  Next, in a standby step (S405), the data reading apparatus 100 waits for execution of a predetermined time process. Next, in the level setting step (S406), the peripheral frequency determination unit 180 sets the channel of the peripheral frequency to the channel 4 that is the (N-2) level channel. Next, in the peripheral frequency interference level detection step (S407), the peripheral frequency interference level detection unit 184 detects the interference level of the peripheral frequency of the channel set in (S406). That is, here, the peripheral frequency interference level detection unit 184 detects the interference level of the channel 4 set in (S406). Here, it is assumed that the interference level from channel 1 to channel 9 is in the state of interference level (c) 430 shown in FIG. In the peripheral frequency comparison step and the determination step (S408), since the channel 4 is smaller than the peripheral frequency threshold value of the (N-2) level setting value, the peripheral frequency comparison unit 186 has a peripheral frequency detection value equal to or lower than the peripheral frequency threshold value. It is determined that (YES in S408). Therefore, in the level changing step (S409), the peripheral frequency determining unit 180 increases the variable i by 1. In the level determining step and determining step (S410), the peripheral frequency determining unit 180 determines whether the variable i is greater than 2J. Determine whether. Here, since i is 0 and J is 2, it is determined that i is 2J or less, and the process returns to (S406) to perform carrier sense for the next channel. Therefore, in (S406), the peripheral frequency channel is set to channel 4, which is the (N-1) level channel. (S407) is executed, and in (S408), since the channel 5 is larger than the peripheral frequency threshold value of the (N-1) level setting value, the peripheral frequency comparison unit 186 has a peripheral frequency detection value that is not less than or equal to the peripheral frequency threshold value ( It is determined as NO) in S408.

Therefore, the process proceeds again to (S416), and the designated frequency is designated in (S402). Then, the data reading apparatus 100 performs a first interference level detection step (S403) and a first comparison step (S404). Here, it is assumed that the interference level of the channel assigned to each frequency is in the state of interference level (d) 440 shown in FIG.
As a result of repeating the above processing (S416 to S404), in the first comparison step (S404), the first comparison unit 126 determines that the other data reading device 100 in the vicinity does not use the channel 3.

A standby step (S405) and a level setting step (S406) are performed. Here, carrier sense is performed for channel 1 to channel 5. (N-2) Channel 1 and channel 5 that are level setting values are smaller than (N-2) interference level, and (N-1) Channel 2 and channel 4 that are level setting values are (N-1) ) Less than interference level. Therefore, as a result of repeating the peripheral frequency determination processing (S406 to S410), in the peripheral frequency interference level detection step (S408), the peripheral frequency comparison unit 186 determines that the peripheral frequency detection value is the peripheral for all measured peripheral frequency channels. It is determined that the frequency is equal to or less than the frequency threshold (YES in S408).
In the level determination step and determination step (S410), when carrier sense up to channel 5 is completed, the peripheral frequency determination unit 180 determines that i is greater than 2J (YES in S410), and the determination unit 140 The first comparison unit 126 determines that the first detection value is equal to or lower than the first threshold value, and the peripheral frequency comparison unit 186 determines that the peripheral frequency detection value is equal to or lower than the peripheral frequency threshold value for all channels in the set range. To do.

  Therefore, next, the data reader 100 performs the first interference level detection step (S411) and the first comparison step (S412), and other data readers in the vicinity of the channel 3 even after a predetermined time has elapsed. Make sure 100 is not using channel 3. That is, the data reading apparatus 100 confirms that no radio wave interference occurs with other data reading apparatuses 100 in the vicinity even if the channel 3 is used after a predetermined time has elapsed.

  If the confirmation is obtained (YES in S412), the data reading apparatus 100 performs a command issue step (S413), a response reception step (S414), and an end determination step (S415).

  According to the data reader 100 and the RFID system 300 according to the fourth embodiment, even when a plurality of data readers are arranged in the vicinity by measuring the interference level of the peripheral frequency, the interference between the data readers 100, By preventing interference between the data reading apparatus 100 and the IC tag 200, the data reading apparatus 100 can perform stable communication with the IC tag 200.

  Here, in the above description, the interference levels of a plurality of peripheral frequencies are sequentially measured and compared. However, the Fourier transform is performed, the interference level for each frequency is detected at once, and the interference levels of the respective frequencies are compared. Good.

The RFID system according to the fourth embodiment is summarized as follows: a memory for holding data, a command analysis unit for demodulating a command given from the outside and analyzing the command, a memory control unit for reading or writing the memory, and the memory An IC tag having a command execution unit that performs processing based on the read data and an analysis result in the command analysis unit, and a transmission unit that transmits the data read from the memory;
An RFID system including the IC tag and a data reading device that performs non-contact data communication, wherein the RFID system includes the following means.
The data reading device includes: (a) a transmission unit that transmits a command or an unmodulated wave to the IC tag; (b) a reception unit that receives a response from the IC tag; and (c) a frequency interference level to be used. 1 interference level setting means (d) peripheral frequency interference level setting means (e) for setting interference levels of a plurality of adjacent frequencies that are larger than the interference level set by the first interference level setting means (e) First interference level detection means for performing detection (f) Peripheral frequency interference level detection means for detecting interference levels at a plurality of frequencies adjacent to the frequency to be used (g) Interference level detected by the first interference level detection means Is less than or equal to the interference level set by the first interference level setting means, and the interference level detected by the peripheral frequency interference level detection means is When it is the interference level below which is set at a frequency interference level setting means includes a control unit which controls transmission of commands or unmodulated wave from the transmitting unit.

It is a figure which shows an example of the hardware constitutions of the data reading apparatus 100 in embodiment. 2 is a functional block diagram showing functions of an RFID system 300 including a data reading device 100 and an IC tag 200 according to Embodiment 1. FIG. It is a figure which shows the interference level (a) 410 of the channel allocated to each frequency at a certain time. It is a figure which shows the interference level (b) 420 of the channel allocated to each frequency at a certain time. 3 is a flowchart illustrating an interference determination method that is an operation of the RFID system 300 including the data reading device 100 and the IC tag 200 according to the first embodiment. FIG. 6 is a functional block diagram illustrating functions of an RFID system 300 including a data reading device 100 and an IC tag 200 according to a second embodiment. 5 is a flowchart illustrating an interference determination method that is an operation of an RFID system 300 including a data reading device 100 and an IC tag 200 according to a second embodiment. FIG. 6 is a functional block diagram illustrating functions of an RFID system 300 including a data reading device 100 and an IC tag 200 according to a third embodiment. 10 is a flowchart illustrating an interference determination method that is an operation of the RFID system 300 including the data reading apparatus 100 and the IC tag 200 according to the third embodiment. FIG. 6 is a functional block diagram illustrating functions of an RFID system 300 including a data reading device 100 and an IC tag 200 according to a fourth embodiment. It is a figure which shows the interference level (c) 430 of the channel allocated to each frequency in a certain time. It is a figure which shows the interference level (d) 440 of the channel allocated to each frequency at a certain time. It is the figure which showed the frequency vs. noise characteristic of an IC tag. 10 is a flowchart illustrating an interference determination method that is an operation of an RFID system 300 including a data reading device 100 and an IC tag 200 according to a fourth embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 Data reader, 110 Frequency designation part, 120 1st determination part, 122 1st interference level setting part, 124 1st interference level detection part, 126 1st comparison part, 130 2nd determination part, 132 2nd interference level setting 134, second interference level detection unit, 136 second comparison unit, 140 determination unit, 150 transmission unit, 160 reception unit, 170 notification channel determination unit, 172 notification channel interference level setting unit, 174 notification channel interference level detection unit, 176 Notification channel comparison unit, 180 ambient frequency determination unit, 182 ambient frequency interference level setting unit, 184 ambient frequency interference level detection unit, 186 ambient frequency comparison unit, 410 interference level (a), 420 interference level (b), 430 interference Level (c), 440 Interference level (d), 901 LCD, 902 touch 904 FDD, 905 CDD, 908 database, 909 system unit, 910 server, 911 CPU, 912 bus, 913 ROM, 914 RAM, 915 communication board, 920 magnetic disk unit, 921 OS, 922 window system, 923 program group, 924 file group, 940 Internet, 941 gateway, 942 LAN, 980 processing device, 982 input device, 984 storage device, 986 communication device.

Claims (22)

An interference determination apparatus that determines whether or not a radio wave used in an RFID (Radio Frequency IDentification) system including an IC (Integrated Circuit) tag and a data reader interferes with a predetermined radio wave.
A frequency designating unit for designating a designated frequency that is a frequency of the predetermined radio wave by an input device;
A first interference level setting unit that sets a first threshold value that is a threshold value of an interference level of a designated frequency designated by the frequency designation unit, and stores the first threshold value in a storage device;
A first interference level detector that detects a first detection value that is an interference level of the specified frequency and stores the first detection value in a storage device;
The first threshold set by the first interference level setting unit and the first detection value detected by the first interference level detection unit are compared, and whether or not the first detection value is less than or equal to the first threshold is determined by the processing device. A first comparison unit for determining;
A second interference level setting unit that sets a second threshold that is a threshold of an interference level of a designated frequency band that is a frequency band including the designated frequency of a plurality of frequency bands assigned to the RFID system, and stores the second threshold in a storage device;
A second interference level detector that detects a second detection value that is an interference level in the designated frequency band and stores the second detection value in a storage device;
The second threshold set by the second interference level setting unit and the second detection value detected by the second interference level detection unit are compared, and whether or not the second detection value is equal to or less than the second threshold is determined by the processing device. A second comparison unit for determining;
When the first comparison unit determines that the first detection value is less than or equal to the first threshold value, and the second comparison unit determines that the second detection value is less than or equal to the second threshold value, radio waves do not interfere with each other. An interference determination device comprising: a determination unit configured to determine by a processing device. The second interference level detection unit detects the interference level of each channel of the plurality of channels allocated to the designated frequency band as a second detection value, and stores it in a storage device.
The second comparison unit compares the second threshold value with each second detection value for each channel detected by the second interference level detection unit, and whether each second detection value for each channel is equal to or less than the second threshold value. Judge whether or not
The determination unit determines that the first comparison unit determines that the first detection value is less than or equal to a first threshold value, and the second comparison unit determines that all the second detection values for each channel are less than or equal to the second threshold value. The interference determination device according to claim 1, wherein when the determination is made, the radio wave is determined not to interfere.   The interference determination apparatus according to claim 1, wherein the second threshold set by the second interference level setting unit is larger than the first threshold set by the first interference level setting unit. The first interference level setting unit sets a first threshold based on the magnitude of the output for transmitting the radio wave of the specified frequency,
The interference determination apparatus according to claim 1, wherein the second interference level setting unit sets a second threshold based on a magnitude of an output for transmitting a radio wave having the designated frequency. Data reading that transmits an IC (Integrated Circuit) tag and a notification wave, which is a radio wave for communication, to the IC tag to a notification channel assigned to a predetermined frequency. In an interference determination device for determining whether or not a radio wave used in an RFID (Radio Frequency IDentification) system including a device interferes with a predetermined radio wave,
A frequency designating unit for designating a designated frequency that is a frequency of the predetermined radio wave by an input device;
A first interference level setting unit that sets a first threshold value that is a threshold value of an interference level of a designated frequency designated by the frequency designation unit, and stores the first threshold value in a storage device;
A first interference level detector that detects a first detection value that is an interference level of the specified frequency and stores the first detection value in a storage device;
The first threshold set by the first interference level setting unit and the first detection value detected by the first interference level detection unit are compared, and whether or not the first detection value is less than or equal to the first threshold is determined by the processing device. A first comparison unit for determining;
A notification channel interference level setting unit that sets a notification channel threshold that is a threshold of the interference level of the notification channel and stores the notification channel threshold in a storage device;
A notification channel interference level detection unit that detects a notification channel detection value that is an interference level of the notification channel and stores it in a storage device;
The notification channel threshold set by the notification channel interference level setting unit is compared with the notification channel detection value detected by the notification channel interference level detection unit, and whether or not the notification channel detection value is equal to or less than the notification channel threshold is determined by the processing device. A notification channel comparison unit for determining;
When the first comparison unit determines that the first detection value is less than or equal to the first threshold value and the notification channel comparison unit determines that the notification channel detection value is less than or equal to the notification channel threshold value, radio waves do not interfere An interference determination device comprising: a determination unit configured to determine by a processing device.   6. The interference determination device according to claim 5, wherein the notification channel threshold set by the notification channel interference level setting unit is larger than the first threshold set by the first interference level setting unit. The first interference level setting unit sets a first threshold based on the magnitude of the output for transmitting the radio wave of the specified frequency,
6. The interference determination apparatus according to claim 5, wherein the notification channel interference level setting unit sets a notification channel threshold based on a magnitude of an output for transmitting a radio wave having the designated frequency. Used in an RFID (Radio Frequency IDentification) system including an IC (Integrated Circuit) tag and a data reader that transmits radio waves of a predetermined frequency to the IC tag and receives radio waves of a frequency different from the predetermined frequency from the IC tag. In an interference determination device that determines whether or not a radio wave being interfered with a predetermined radio wave,
A frequency designating unit for designating a designated frequency that is a frequency of the predetermined radio wave by an input device;
A second interference level setting unit that sets a second threshold that is a threshold of an interference level of a designated frequency band that is a frequency band including the designated frequency of a plurality of frequency bands assigned to the RFID system, and stores the second threshold in a storage device;
A second interference level detector that detects a second detection value that is an interference level in the designated frequency band and stores the second detection value in a storage device;
The second threshold set by the second interference level setting unit and the second detection value detected by the second interference level detection unit are compared, and whether or not the second detection value is equal to or less than the second threshold is determined by the processing device. A second comparison unit for determining;
An interference determination apparatus comprising: a determination unit configured to determine that a radio wave does not interfere when the second comparison unit determines that the second detection value is equal to or less than a second threshold value. 9. The interference determination apparatus according to claim 8, wherein the second interference level setting unit sets the second threshold based on the magnitude of the output for transmitting the radio wave having the designated frequency. An interference determination apparatus that determines whether or not a radio wave used in an RFID (Radio Frequency IDentification) system including an IC (Integrated Circuit) tag and a data reader interferes with a predetermined radio wave.
A frequency designating unit for designating a designated frequency that is a frequency of the predetermined radio wave by an input device;
A first interference level setting unit that sets a first threshold value that is a threshold value of an interference level of a designated frequency designated by the frequency designation unit, and stores the first threshold value in a storage device;
A first interference level detector that detects a first detection value that is an interference level of the specified frequency and stores the first detection value in a storage device;
The first threshold set by the first interference level setting unit and the first detection value detected by the first interference level detection unit are compared, and whether or not the first detection value is less than or equal to the first threshold is determined by the processing device. A first comparison unit for determining;
A peripheral frequency interference level setting unit that sets a peripheral frequency threshold that is a threshold of an interference level of the peripheral frequency and stores it in a storage device using a predetermined frequency within a predetermined range from the specified frequency as a peripheral frequency;
A peripheral frequency interference level detector that detects a peripheral frequency detection value that is an interference level of the peripheral frequency and stores it in a storage device;
The peripheral frequency threshold set by the peripheral frequency interference level setting unit is compared with the peripheral frequency detection value detected by the peripheral frequency interference level detection unit, and whether or not the peripheral frequency detection value is equal to or less than the peripheral frequency threshold is determined by the processing device. A peripheral frequency comparison unit for determination;
When the first comparison unit determines that the first detection value is equal to or lower than the first threshold value, and the peripheral frequency comparison unit determines that the peripheral frequency detection value is equal to or lower than the peripheral frequency threshold value, radio waves do not interfere with each other. An interference determination device comprising: a determination unit configured to determine by a processing device.   11. The interference determination device according to claim 10, wherein the peripheral frequency threshold set by the peripheral frequency interference level setting unit is larger than the first threshold set by the first interference level setting unit. The peripheral frequency interference level setting unit sets each frequency of a plurality of predetermined frequencies within a predetermined range from the specified frequency as a peripheral frequency, and sets a larger value to the peripheral frequency threshold as the peripheral frequency is away from the specified frequency. And
The peripheral frequency interference level detection unit detects a peripheral frequency detection value of each of the plurality of predetermined frequencies,
The peripheral frequency comparison unit compares a peripheral frequency threshold value with a peripheral frequency detection value for each of the plurality of predetermined frequencies, and determines whether the peripheral frequency detection value is equal to or less than the peripheral frequency threshold value. ,
The determination unit determines that the first comparison unit determines that the first detection value is less than or equal to a first threshold value, and the peripheral frequency comparison unit detects peripheral frequencies for all of the plurality of predetermined frequencies. The interference determination device according to claim 10, wherein when it is determined that the value is equal to or less than the peripheral frequency threshold, the radio wave is determined not to interfere. An interference judgment device according to claim 1;
When the determination unit of the interference determination device determines that the radio wave does not interfere, a transmission unit that transmits a command to the IC tag by the communication device;
A data reading apparatus comprising: a receiving unit that receives a response to a command transmitted from the IC tag from the IC tag. An interference judgment device according to claim 5;
When the determination unit of the interference determination device determines that radio waves do not interfere, the transmission unit includes a transmission unit that transmits a command to the IC tag by the communication device, and a reception unit that receives a response to the command transmitted by the transmission unit from the IC tag. A data reader characterized by the above. An interference judgment device according to claim 8,
When the determination unit of the interference determination device determines that radio waves do not interfere, the transmission unit includes a transmission unit that transmits a command to the IC tag by the communication device, and a reception unit that receives a response to the command transmitted by the transmission unit from the IC tag. A data reader characterized by the above. An interference judgment device according to claim 10;
When the determination unit of the interference determination device determines that radio waves do not interfere, the transmission unit includes a transmission unit that transmits a command to the IC tag by the communication device, and a reception unit that receives a response to the command transmitted by the transmission unit from the IC tag. A data reader characterized by the above. An RFID system comprising the data reading device according to claim 13 and an IC tag,
IC tag is
An IC tag receiver that receives the command transmitted by the transmitter of the data reader by the communication device;
An RFID system comprising: an IC tag transmission unit that performs processing based on a command received by the IC tag reception unit and transmits a processing result by a communication device. An RFID system comprising the data reader according to claim 14 and an IC tag,
IC tag is
An IC tag receiver that receives the command transmitted by the transmitter of the data reader by the communication device;
An RFID system comprising: an IC tag transmission unit that performs processing based on a command received by the IC tag reception unit and transmits a processing result by a communication device. An RFID system comprising the data reader according to claim 15 and an IC tag,
IC tag is
An IC tag receiver that receives the command transmitted by the transmitter of the data reader by the communication device;
An RFID system comprising: an IC tag transmission unit that performs processing based on a command received by the IC tag reception unit and transmits a processing result by a communication device. An RFID system comprising the data reader according to claim 16 and an IC tag,
IC tag is
An IC tag receiver that receives the command transmitted by the transmitter of the data reader by the communication device;
An RFID system comprising: an IC tag transmission unit that performs processing based on a command received by the IC tag reception unit and transmits a processing result by a communication device. In an interference determination method of an interference determination device for determining whether or not a radio wave used in an RFID (Radio Frequency IDentification) system including an IC (Integrated Circuit) tag and a data reader interferes with a predetermined radio wave.
A frequency designating step in which a frequency designating unit designates a designated frequency which is a frequency of the predetermined radio wave by an input device;
A first interference level setting step in which a first threshold value that is a threshold value of an interference level of a specified frequency specified in the frequency specifying step is set by a first interference level setting unit and stored in a storage device;
A first interference level detection step in which a first detection value that is an interference level of the designated frequency is detected by a first interference level detection unit and stored in a storage device;
Whether the first comparison unit compares the first threshold value set in the first interference level setting step and the first detection value detected in the first interference level detection step, and is the first detection value equal to or less than the first threshold value? A first comparison step in which the first comparison unit determines whether or not by the processing device;
A second interference level setting unit sets a second threshold value that is a threshold value of an interference level of a designated frequency band that is a frequency band including the designated frequency of a plurality of frequency bands assigned to the RFID system, and stores the second threshold value in a storage device. An interference level setting step;
A second interference level detecting step in which a second detection value that is an interference level of the designated frequency band is detected by a second interference level detector and stored in a storage device;
Whether the second comparison unit compares the second threshold value set in the second interference level setting step with the second detection value detected in the second interference level detection step, and is the second detection value equal to or less than the second threshold value? A second comparison step in which the second comparison unit determines whether or not by the processing device;
If it is determined in the first comparison step that the first detection value is less than or equal to the first threshold value, and if the second detection value is determined to be less than or equal to the second threshold value in the second comparison step, radio waves do not interfere. An interference determination method comprising: a determination step for a determination unit to determine by a processing device. In an interference determination program of an interference determination device that determines whether a radio wave used in an RFID (Radio Frequency IDentification) system including an IC (Integrated Circuit) tag and a data reader interferes with a predetermined radio wave,
A frequency designating step in which a frequency designating unit designates a designated frequency which is a frequency of the predetermined radio wave by an input device;
A first interference level setting step in which a first threshold value that is a threshold value of an interference level of a specified frequency specified in the frequency specifying step is set by a first interference level setting unit and stored in a storage device;
A first interference level detection step in which a first detection value that is an interference level of the designated frequency is detected by a first interference level detection unit and stored in a storage device;
Whether the first comparison unit compares the first threshold value set in the first interference level setting step and the first detection value detected in the first interference level detection step, and is the first detection value equal to or less than the first threshold value? A first comparison step in which the first comparison unit determines whether or not by the processing device;
A second interference level setting unit sets a second threshold value that is a threshold value of an interference level of a designated frequency band that is a frequency band including the designated frequency of a plurality of frequency bands assigned to the RFID system, and stores the second threshold value in a storage device. An interference level setting step;
A second interference level detecting step in which a second detection value that is an interference level of the designated frequency band is detected by a second interference level detector and stored in a storage device;
Whether the second comparison unit compares the second threshold value set in the second interference level setting step with the second detection value detected in the second interference level detection step, and is the second detection value equal to or less than the second threshold value? A second comparison step in which the second comparison unit determines whether or not by the processing device;
If it is determined in the first comparison step that the first detection value is less than or equal to the first threshold value, and if the second detection value is determined to be less than or equal to the second threshold value in the second comparison step, radio waves do not interfere. An interference determination program that causes a computer to execute a determination step that is determined by a determination unit by a processing device.

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