JP4747221B2 - Wireless communication device - Google Patents

Description

  The present invention relates to a wireless communication apparatus that writes and reads data using wireless communication from a wireless communication medium such as an RFID (Radio Frequency Identification) tag.

  In recent years, a wireless communication system called an RFID system has attracted attention. This system performs non-contact data writing and reading by performing wireless communication between a small wireless communication medium having an IC chip and an antenna and the wireless communication medium using radio waves or electromagnetic waves. It consists of a wireless communication device, so-called RFID reader / writer.

  The IC chip of the wireless communication medium stores a unique ID such as a serial number set at the time of manufacture. In addition, the wireless communication medium can be thinned and can be easily attached to an article. For this reason, the wireless communication medium is called an RFID tag, a wireless tag, or the like, and is usually used by being attached to each article to be managed.

  On the other hand, an RFID reader / writer is a reader / writer as a wireless communication device that performs radio communication or non-contact data communication with a wireless communication medium via an antenna unit that exchanges radio waves or electromagnetic waves with a wireless communication medium. It consists of a writer body. The RFID reader / writer is classified into a gate type, a stationary type, a portable type, and the like depending on the shape of the antenna portion. The gate-type RFID reader / writer is used, for example, in an anti-theft system or a gate management system. The stationary RFID reader / writer is used, for example, in a library lending management system or a store product sales data processing system. The handy type RFID reader / writer is used for an article retrieval system in a warehouse, an inventory system in a store, and the like.

  By the way, generally, the RFID system uses a frequency band of 13.56 MHz or 2,45 GHz. Recently, the UHF band of 860 to 960 MHz has been used. However, since the UHF band is mainly used as a frequency band of a mobile phone, the frequency band between the mobile phone and the RFID system does not overlap and disturb the radio wave situation, and the frequency range is 950 to 954 MHz among 860 to 960 MHz. UHF band (radio channel cn1 to radio channel cn9) or 952 to 955 MHz UHF band (radio channel cn1 to radio channel cn14) is allocated to the RFID system.

  On the other hand, when constructing an RFID system, not only one RFID reader / writer but also a plurality of devices are used in most cases. For this reason, carrier sense by the LBT (Listen Before Talk) method is performed so that radio waves emitted from a plurality of RFID readers / writers do not interfere. That is, an empty channel is searched before the RFID reader / writer emits radio waves, and if an empty channel is detected, radio waves are output using that channel.

  In a conventional RFID reader / writer using such a carrier sense method, when a communication abnormality in communication with a wireless communication medium is detected, an empty channel is detected again after a predetermined transmission pause time, and this detected empty channel is detected. There is one in which communication with a wireless communication medium is resumed using (see, for example, Patent Document 1).

JP 2007-066761 A

  However, even if an RFID reader / writer detects an empty channel and performs data communication with a wireless communication medium, another RFID reader / writer with an adjacent communication area uses a channel with a frequency very close to that of the empty channel. When wireless communication is performed, a communication error may occur due to the influence.

  The present invention has been made based on such circumstances, and the object of the present invention is to improve the communication efficiency by avoiding a communication error due to the influence of another wireless communication device adjacent to the communication area as much as possible. A communication device is to be provided.

The present invention provides a wireless communication apparatus that performs wireless communication using an empty channel detected from a plurality of wireless channels between a wireless communication medium including an IC chip and an antenna . A first table that stores a plurality of types of switching condition data that defines a condition for executing switching of radio channels for searching for empty channels, in what order to search for empty channels by switching a plurality of radio channels A second table that stores a plurality of types of channel switching pattern data, and an identification code that identifies each of the plurality of wireless communication devices and that is adjacent to the wireless communication device specified by the identification code Identification code of the wireless communication device, switching condition data and channel switching pattern set for the wireless communication device specified by the identification code When a wireless communication device is selected from a plurality of wireless communication devices, an identification code of another wireless communication device adjacent to the selected wireless communication device is obtained. Obtained from the third table, searches the third table with the obtained identification code, and stores it in the first table other than the switching condition data stored corresponding to the identification code. One of the switching condition data is set in the third table in correspondence with the identification code of the selected wireless communication device, and further, the third table is searched for other wireless devices other than the selected wireless communication device. Other than the channel switching pattern data stored corresponding to the identification code of the communication device, one of the channel switching pattern data stored in the second table is stored in the identification of the selected wireless communication device. A server to be set in the third table in correspondence to the code, is connected via a network, the server receives a channel switching pattern data set in the third table corresponds to own identification code In wireless communication between the pattern storage means for storing, the condition storage means for receiving and storing the switching condition data set in the third table corresponding to the identification code from the server, and the wireless communication medium, When the condition of the switching condition data stored in the condition storage unit is satisfied, switching of the radio channel for searching for an empty channel from a plurality of radio channels is executed according to the channel switching pattern data stored in the pattern storage unit Switching condition data stored in the condition storage means is stored in another adjacent wireless communication device. The switching conditions are different from those determined by the data stored in the condition storage means.

  According to the present invention in which such a measure is taken, it is possible to avoid a communication error due to the influence of another wireless communication apparatus adjacent to the communication area as much as possible, and to improve the communication efficiency.

The block diagram which shows schematic structure of the merchandise sales data processing system which is one embodiment of this invention. The schematic diagram which shows the main data tables which a store server has in the embodiment. FIG. 3 is a schematic diagram illustrating a data structure example of a switching condition table in FIG. 2. FIG. 3 is a schematic diagram illustrating a data structure example of a switching pattern table in FIG. 2. FIG. 3 is a schematic diagram illustrating a data structure example of a reader / writer setting table in FIG. 2. FIG. 3 is a block diagram showing a main configuration of the RFID reader / writer in the embodiment. FIG. 3 is a schematic diagram showing main memory areas formed in a storage unit of the RFID reader / writer in the embodiment. 6 is a flowchart showing a main processing procedure of reader / writer setting work executed by the store server in the embodiment. 4 is a flowchart showing a main processing procedure executed by the control unit of the RFID reader / writer in the embodiment. FIG. 10 is a flowchart showing a subsequent processing procedure when the condition code m is “C0” in ST37 of FIG. 9; FIG. 10 is a flowchart showing a subsequent processing procedure when the condition code m is “C1” in ST37 of FIG. 9; FIG. 10 is a flowchart showing a subsequent processing procedure when the condition code m is “C2” in ST37 of FIG. 9;

  The best mode for carrying out the present invention will be described below with reference to the drawings. In this embodiment, in a store such as a supermarket, a customer purchases by reading RFID tag data attached to each product with an RFID reader / writer connected to a POS (Point Of Sales) terminal. This is a case where the wireless communication system of the present invention is applied to a product sales data processing system that processes product sales data.

  FIG. 1 is a block diagram showing an embodiment of a merchandise sales data processing system. This system includes a plurality of (four in the figure) POS terminals 1-1, 1-2, 1-3, 1-4, and POS terminals 1-1, 1-2, 1-3, 1-4. Is connected to a store server 2 that controls the network 3 via a network 3 such as a LAN (Local Area Network). In addition, RFID readers / writers 4-1, 4-2, 4-3, 4-4 are provided on a one-to-one basis for the respective POS terminals 1-1, 1-2, 1-3, 1-4. ing.

  Each of the RFID reader / writers 4-1, 4-2, 4-3, and 4-4 includes antennas 5-1, 5-2, 5-3, and 5-4, and the antennas 5-1, Wireless communication is performed with RFID tags existing in the communication areas 5-2, 5-3, and 5-4. And the data memorize | stored in the memory part of the RFID tag are read non-contactingly, or data is written in this memory part non-contactingly. Here, the RFID reader / writers 4-1, 4-2, 4-3, and 4-4 function as the wireless communication device of the present invention. The RFID tag functions as a wireless communication medium accessed by the wireless communication device.

  The RFID tag is composed of an antenna and an IC chip. The IC chip is provided with a power generation unit, a demodulation unit, a modulation unit, a memory unit, a control unit for controlling these, and the like. In this embodiment, the RFID reader / writer 4 and the RFID tag perform data communication using the UHF band (wireless channel cn1 to wireless channel cn9) of 952 to 954 MHz. That is, when the RFID tag receives a UHF band radio wave with an antenna, a power source is generated and activated by the action of the power generation unit. A response wave including a unique ID stored in the memory unit is radiated from the antenna from the activated RFID tag. If the RFID reader / writer 1 that has received the response wave is connected to a wireless line, then the received data is demodulated and written to the memory unit in accordance with a command from the RFID reader / writer 1. Or the data in the memory unit is read and modulated and sent to the RFID reader / writer. Such an RFID tag is attached to each product sold in a store. In addition, in the memory part of each RFID tag, product data such as a single product code for specifying a product to which the tag is attached is stored in advance in addition to a unique ID.

  Each RFID reader / writer 4-1, 4-2, 4-3, 4-4 has a plurality of antennas 5-1, 5-2, 5-3, 5-4 arranged in parallel at the store accounting. One checkout counter is provided for each. When a product is placed on the checkout counter, the RFID tag data attached to the product is transferred to the RFID reader / writer via the antennas 5-1, 5-2, 5-3, 5-4. The writers 4-1, 4-2, 4-3, and 4-4 are configured to read each. The POS terminals 1-1, 1-2, 1-3, and 1-4 use the product data read from the RFID tag by the corresponding RFID reader / writer 4-1, 4-2, 4-3, and 4-4. The sales data of the product purchased by the customer is registered.

  The store server 2 collects and aggregates the product sales data registered in each POS terminal 1-1, 1-2, 1-3, 1-4 via the network 3, and sales, inventory, etc. of the entire store Is configured to manage data. Further, as shown in FIG. 2, a switching condition table 11 and a switching pattern table 12 are used as data tables for controlling the operation of each RFID reader / writer 4-1, 4-2, 4-3, 4-4. And a reader / writer setting table 13.

  The switching condition table 11 is a data table that defines when a condition for switching a wireless channel for searching for a free channel from a plurality of wireless channels is established, as shown in FIG. Different condition data is stored in association with the unique condition code. In the present embodiment, condition data for switching the radio channel when a carrier sense error occurs is set for the condition code C1, and data communication is performed with respect to the RFID tag for the condition code C2. The condition data that switches the radio channel each time the command, that is, the process corresponding to the read command and the write command is executed is set. For the condition code C3, in addition to the occurrence of the carrier sense error, A condition is set that the wireless channel is switched even when a communication error occurs. Note that a communication error is an error that occurred during the data communication procedure with an RFID tag when a response signal was received from the RFID tag, and a frequency close to the frequency used by another RFID reader / writer is used. This is a bit missing error or a bit garbled error caused by noise that may occur when the

  The switching pattern table 12 is a data table that defines what radio channel is used and in what order the channel is switched to search for an empty channel, and is associated with a unique pattern code as shown in FIG. The selection order data of nine channels from the wireless channel cn1 to the wireless channel cn9 are stored. In addition, a use flag that is turned on (1) when any RFID reader / writer uses corresponding selection order data is also stored in association with each pattern code. In the selection order data, “0” indicates unselected. The number of pattern codes is larger than the number of RFID readers / writers that construct the system.

  In the present embodiment, selection order data [123456789] is set for the pattern code P1, selection order data [987654321] is set for the pattern code P2, and for the pattern code P3, Selection order data [403000102] is set, selection order data [430000021] is set for pattern code P4, and selection order data [000132000] is set for pattern code P5. Here, the selection order data [123456789] indicates that the radio channels are switched in the order of [cn1-> cn2-> cn3-> cn4-> cn5-> cn6-> cn7-> cn8-> cn9-> cn1 ...]. The selection order data [987654321] indicates that the radio channel is switched in the order of [cn9 → cn8 → cn7 → cn6 → cn5 → cn4 → cn3 → cn2 → cn1 → cn9]. The selection order data [403000102] indicates that the radio channel is switched in the order of [cn7 → cn9 → cn3 → cn1 → cn7. The selection order data [430000021] indicates that the radio channels are switched in the order of [cn8 → cn9 → cn2 → cn1 → cn8. The selection order data [000132000] indicates that the radio channels are switched in the order of [cn4 → cn6 → cn5 → cn4.

  The reader / writer setting table 13 is a data table that defines what switching conditions and channel switching patterns are set for each RFID reader / writer 4-1, 4-2, 4-3, 4-4. As shown in FIG. 5, a plurality of adjacent ID areas (adjacent IDb, adjacent IDc) are associated with the RWID (self IDa) of each RFID reader / writer 4-1, 4-2, 4-3, 4-4. , A condition code memory and a pattern code area. In the adjacent ID area, the RWID of another RFID reader / writer having a communication area adjacent to its own communication area is set. The RWID is used to identify the RFID reader / writer 4-1, 4-2, 4-3, 4-4, respectively, so that the RFID reader / writer 4-1, 4-2, 4-3, 4- It is a unique identification code (ID) set in advance for every four.

  In the present embodiment, a checkout counter provided with the antenna 5-2 of the RFID reader / writer 4-2 is arranged next to the checkout counter provided with the antenna 5-1 of the RFID reader / writer 4-1. Further, a checkout counter provided with an antenna 5-3 of the RFID reader / writer 4-3 is arranged next to it, and an antenna 5-4 of the RFID reader / writer 4-4 is provided next to the checkout counter. Checkout counter is arranged. That is, the RFID reader / writer 4-1 and the RFID reader / writer 4-2 have adjacent communication areas. The RFID reader / writer 4-2 and the RFID reader / writer 4-3 are adjacent to each other in the communication area. The RFID reader / writer 4-3 and the RFID reader / writer 4-4 are adjacent to each other in the communication area. Therefore, the identification code [RWID2] of the RFID reader / writer 4-2 is set in the adjacent ID area in association with the identification code [RWID1] of the RFID reader / writer 4-1. Further, the identification code [RWID1] of the RFID reader / writer 4-1 and the identification code [RWID3] of the RFID reader / writer 4-3 are adjacent IDs in association with the identification code [RWID2] of the RFID reader / writer 4-2. It is set in the area. Further, in association with the identification code [RWID3] of the RFID reader / writer 4-3, the identification code [RWID2] of the RFID reader / writer 4-2 and the identification code [RWID4] of the RFID reader / writer 4-4 are adjacent IDs. It is set in the area. Further, the identification code [RWID3] of the RFID reader / writer 4-3 is set in the adjacent ID area in association with the identification code [RWID4] of the RFID reader / writer 4-4.

  FIG. 6 is a block diagram showing a main configuration of the RFID reader / writer 4-1, 4-2, 4-3, 4-4. Since each RFID reader / writer 4-1, 4-2, 4-3, 4-4 has the same configuration, the RFID reader / writer symbols 4-1, 4-2, 4-3, 4-4 are designated as “ The configuration of the antenna 4-1, the antennas 5-1, 5-2, 5-3, and 5-4 will be collectively referred to as “5”.

  The RFID reader / writer 4 includes a control unit 21 mainly composed of a CPU (Central Processing Unit), a storage unit 22 having a ROM (Read Only Memory) area and a RAM (Random Access Memory) area, and data communication with the POS terminal 1. A communication unit 23 for performing communication, a timer unit 24 for counting a monitoring time and an operation control time, which will be described later, a wireless circuit unit 25 for controlling wireless data transmission and reception, and a carrier sense unit 26. .

  The radio circuit unit 25 includes a PLL (Phase Locked Loop) circuit 31, a transmission unit 32, a circulator 33, a reception unit 34, and the like. The PLL circuit 31 generates a high-frequency sine wave signal. The transmission unit 32 modulates the transmission data sent from the control unit 21, amplifies a signal obtained by adding the modulated signal and the high frequency signal generated by the PLL circuit 31, and outputs the amplified signal to the circulator 33. The circulator 33 has a characteristic that the signal input from the transmission unit 32 is output to the antenna 5, and the signal input from the antenna 5 is output to the reception unit 34. The receiving unit 34 amplifies the high-frequency signal input via the circulator 33, then combines the amplified high-frequency signal and the high-frequency signal of the PLL circuit 31 to convert it to a baseband signal, and demodulates the baseband signal. And output to the control unit 21.

  The carrier sense unit 26 determines the usage status of the radio channel (channel cn1 to channel cn9 of 952 to 954 MHz) in the UHF band used by the RFID reader / writer 4 by carrier sense based on the LBT method. Incidentally, in the LBT method, the operable time of one time of the reader / writer is limited to a maximum of 4 seconds. When one operation is completed, the operation pauses for 50 ms, and after that, an empty channel can be reactivated only after monitoring for 5 ms.

  As shown in FIG. 7, a channel pattern table 41, a condition code memory 42, an initial frequency memory 43, a channel counter memory 44, a retry count setting value memory 45, a retry counter memory 46, and the like are formed in the RAM area of the storage unit 22. is doing. The channel pattern table 41 functions as a pattern storage unit that stores channel pattern data indicating a radio channel switching order for searching for an empty channel. The condition code memory 42 functions as condition storage means for storing radio channel switching condition data. Other functions of the memory areas 43 to 46 will be described as appropriate in the operation of the RFID reader / writer 4 described later.

  The store server 2 can execute a reader / writer setting job as one of the program jobs. When the reader / writer setting job is selected from the job menu of the store server 2, the store server 2 executes the process of the procedure shown in the flowchart of FIG.

  First, the store server 2 displays the ID input screen of the RFID reader / writer 4 on the display as ST (step) 1. In this screen, an input area for the identification code [RWID] of the RFID reader / writer 4 is formed. Therefore, the store server 2 waits for the identification code [RWID] to be input as ST2. Here, when the business end instruction input is received without the identification code [RWID] being input (YES in ST3), the store server 2 ends the processing of the reader / writer setting business.

  When the identification code [RWID] is input to the RWID input area of the ID input screen (YES in ST2), the store server 2 refers to the reader / writer setting table 13 as ST4, and the input identification code [RWID] The adjacent IDb and the adjacent IDc set in the record having the self IDa are acquired and stored in the work memory. Further, the store server 2 resets the counter j to “0” in ST5.

  Next, the store server 2 refers to the reader / writer setting table 13 as ST6, and stores the condition code Cj (Cj of Cj) in the condition code memory of the record having the adjacent IDb and the adjacent IDc stored in the work memory as their own IDa. It is determined whether or not “j” is the value of counter j). That is, it is determined whether or not the condition code Cj is being used by the RFID reader / writer adjacent to itself. When the condition code Cj is not stored, that is, when it is not in use (NO in ST6), the store server 2 records the record having the input ID code [RWID] of the reader / writer setting table 13 as its own IDa as ST9. The condition code Cj is written in the condition code memory.

  On the other hand, when the condition code Cj is stored, that is, in use (YES in ST6), the store server 2 increments the counter j by “1” as ST7. Then, in ST8, it is determined whether or not the counter j exceeds the maximum value jmax. If the counter j does not exceed the maximum value jmax (NO in ST8), the store server 2 returns to the process in ST6, and whether or not the condition code Cj is being used by the RFID reader / writer adjacent to itself. Judging.

  Incidentally, in this embodiment, as shown in FIG. 3, since there are three types of condition codes “C0”, “C1”, and “C2”, the maximum value jmax is “2”. On the other hand, the maximum number of communication areas adjacent to the communication area of one RFID reader / writer is “2”. Therefore, even if one uses the condition code C0 and the other uses the condition code C1, the condition code C2 is free. That is, the counter j does not exceed the maximum value jmax in ST8. However, depending on the antenna layout of each RFID reader / writer, the communication area of three or more other antennas may be adjacent to the communication area of one antenna. In this case, the counter j has a maximum value jmax. May be exceeded. In such a case, for example, an arbitrary condition code Cj may be set in the reader / writer setting table 13 by manual input by an operator.

  If the condition code Cj is written in the condition code memory of the reader / writer setting table 13 in ST9, the store server 2 displays an unused pattern list on the display as ST10. This list is a list of pattern codes and selection order data of records in which the use flag is turned off (0) in the switching pattern table 12, and any one of the pattern codes Ps can be selected. When the pattern code Ps is selected (YES in ST11), the store server 2 writes the pattern code Ps in the pattern code area of the record having the input identification code [RWID] in the reader / writer setting table 13 as its own IDa. Further, the use flag corresponding to the pattern code Ps of the switching pattern table 12 is turned on. Thereafter, the store server 2 returns to ST1 and returns the display screen to the ID input screen of the RFID reader / writer 4. Thereafter, the store server 2 repeatedly executes the processes of ST1 to ST13 until receiving an instruction to end business.

  By executing such a reader / writer setting operation, a condition code and a pattern code are assigned to the reader / writer setting table 13 for each RFID reader / writer 4-1, 4-2, 4-3, 4-4. Can be set.

  For example, in FIG. 1, a condition code and a pattern code are set in the order of RFID reader / writer 4-1, RFID reader / writer 4-4, RFID reader / writer 4-2, RFID reader / writer 4-3. And

  In this case, the operator of the store server 2 first inputs the identification code [RWID1] of the RFID reader / writer 4-1 on the ID input screen. Here, the RFID reader / writer adjacent to the RFID reader / writer 4-1 is the RFID reader / writer 4-2. However, at this time, no condition code is set for the RFID reader / writer 4-2. Therefore, the condition code C0 is set in the condition code memory corresponding to the identification code [RWID1] of the RFID reader / writer 4-1 in the reader / writer setting table 13. Next, the unused pattern list is displayed on the display of the store server 2. Here, it is assumed that the operator has selected the pattern code P5. Then, the pattern code P5 is set in the pattern code area corresponding to the identification code [RWID1] of the RFID reader / writer 4-1 in the reader / writer setting table 13.

  Next, the operator inputs the identification code [RWID4] of the RFID reader / writer 4-4 on the ID input screen. Here, the RFID reader / writer adjacent to the RFID reader / writer 4-4 is the RFID reader / writer 4-3. However, at this time, no condition code is set for the RFID reader / writer 4-3. Therefore, the condition code C0 is set in the condition code memory corresponding to the identification code [RWID4] of the RFID reader / writer 4-4 in the reader / writer setting table 13. Next, an unused pattern list excluding the pattern code P5 is displayed on the display of the store server 2. Here, it is assumed that the operator has selected the pattern code P3. Then, the pattern code P3 is set in the pattern code area corresponding to the identification code [RWID4] of the RFID reader / writer 4-4 in the reader / writer setting table 13.

  Next, the operator inputs the identification code [RWID2] of the RFID reader / writer 4-2 on the ID input screen. Here, the RFID reader / writers adjacent to the RFID reader / writer 4-2 are the RFID reader / writer 4-1 and the RFID reader / writer 4-3, and the condition code for the RFID reader / writer 4-1. Since C0 is set, the counter j is incremented to “1”. Therefore, the condition code C1 is set in the condition code memory corresponding to the identification code [RWID2] of the RFID reader / writer 4-2 in the reader / writer setting table 13. Next, an unused pattern list excluding the pattern codes P3 and P5 is displayed on the display of the store server 2. Here, it is assumed that the operator has selected the pattern code P4. Then, the pattern code P4 is set in the pattern code area corresponding to the identification code [RWID2] of the RFID reader / writer 4-2 in the reader / writer setting table 13.

  Finally, the operator inputs the identification code [RWID3] of the RFID reader / writer 4-3 on the ID input screen. Here, the RFID reader / writer adjacent to the RFID reader / writer 4-3 is the RFID reader / writer 4-2 and the RFID reader / writer 4-4, and the conditions for the RFID reader / writer 4-2 are as follows. The code C1 is incremented to “2” because the condition code C0 is set for the RFID reader / writer 4-4. Accordingly, the condition code C2 is set in the condition code memory corresponding to the identification code [RWID3] of the RFID reader / writer 4-3 in the reader / writer setting table 13. Next, an unused pattern list excluding the pattern codes P3 to P5 is displayed on the display of the store server 2. Here, it is assumed that the operator has selected the pattern code P1. Then, the pattern code P1 is set in the pattern code area corresponding to the identification code [RWID3] of the RFID reader / writer 4-3 in the reader / writer setting table 13.

  In the state where the condition code and the pattern code are set for each RFID reader / writer in the reader / writer setting table 13 as described above, each RFID reader / writer 4-1, 4-2, 4-3, 4 When the power supply -4 is turned on, the control unit 21 operates according to the procedure shown in the flowcharts of FIGS. First, the case where the power of the RFID reader / writer 4-1 is turned on will be described.

  First, the control unit 21 of the RFID reader / writer 4-1 transmits a setting data inquiry command to the store server 2 as ST21. The inquiry command includes the identification code [RWID1] of the RFID reader / writer 4-1. The inquiry command is transmitted to the store server 2 via the network 3 via the corresponding POS terminal 1-1.

  The store server 2 that has received the inquiry command searches the reader / writer setting table 13 and reads the condition code C0 and the pattern code P5 corresponding to the identification code [RWID1] in the command. Next, the switching pattern table 12 is searched to read selection order data corresponding to the pattern code P5. Then, channel pattern data is created based on the selection order data. In the case of the RFID reader / writer 4-1, since the selection order data is [000132000], channel pattern data [cn4, cn6, cn5, 0, 0, 0, 0, 0, 0] is created. The store server 2 returns a setting data response command including the condition code C0 and the channel pattern data [cn4, cn6, cn5, 0, 0, 0, 0, 0, 0]. The response command is transmitted to the RFID reader / writer 4-1 via the network 3 and the POS terminal 1-1.

  The control unit 21 waits for a setting data response command as ST22. When the setting data response command is received (YES in ST22), the control unit 21 stores the condition code C0 in the response command in the condition code memory 42 as ST23. In ST24, channel pattern data [cn4, cn6, cn5, 0, 0, 0, 0, 0, 0] in the response command are set in the channel pattern table 41 in the order of channel numbers n = 1-9. In ST25, the initial frequency memory value k is initialized to "1".

  Thereafter, the control unit 21 waits for a read command or a write command to be input from the POS terminal 1-1 as ST26. If any command is input (YES in ST26), the control unit 21 resets the count value y of the retry counter memory 46 to “0” in ST27. In ST28, the value k of the initial frequency memory 43 is set in the channel counter memory 44. Then, in ST29, the channel pattern table 41 is searched, and it is determined whether or not the channel data cnn of the channel number matching the count value n of the channel counter memory 44 is “0”.

  If the channel data cnn is “0” (YES in ST29), the control unit 21 proceeds to the process in ST32. That is, the count value n of the channel counter memory 44 is incremented by “1”. Then, in ST33, it is determined whether or not the count value n exceeds the maximum value “9” of the channel number. If the count value n exceeds the maximum channel number, the count value n is returned to “1” in ST34. Thereafter, the control unit 21 returns to ST29 and determines whether or not the channel data cnn that matches the channel number n in the channel counter memory 44 is “0”.

  When the channel data cnn is not “0” (NO in ST29), the control unit 21 performs carrier sense at the frequency of the channel data cnn as ST30. That is, the monitoring timer of the timer unit 24 is started, the time until the monitoring timer times out (5 ms in the LTB system), whether the frequency signal of the channel data cnn is received by the receiving unit 34, the carrier The determination is made based on the CS signal read from the sensing unit 26 (ST31: condition determining means). The CS signal is at the “0” level when the receiving unit 34 has not received the frequency signal of the channel data cnn, and at the “1” level when received. In ST31, the control unit 21 determines whether or not the CS signal is at “0” level.

  When the CS signal is “1” level (YES in ST31), the frequency of the channel data cnn is a channel in use. In this case, the control unit 21 proceeds to ST32. As described above, the count value n of the channel counter memory 44 is incremented by “1” (channel switching means). When the count value n exceeds the maximum value “9” of the channel number, the count value n Then, it is determined again whether the channel data cnn of the channel number matching the count value n is “0”.

  When the CS signal is “0” level (NO in ST31), the frequency of the channel data cnn is an empty channel. In this case, the control unit 21 executes command processing using the frequency of the empty channel as ST35. For example, in the case of a read command, the operation limit timer of the timer unit 24 is started, and data is read by performing radio communication with the RFID tag existing in the communication area of the antenna 5-1 at the frequency of the channel data cnn. . If it is a write command, the operation limiting timer of the timer unit 24 is started and data is written by performing wireless communication with the RFID tag existing in the communication area of the antenna 5-1 at the frequency of the channel data cnn. Note that the operation limit timer times out when the maximum operable time 4 s is reached in the LBT method.

  In ST36, the control unit 21 waits for the read operation or the write operation to end or for the operation limit timer to time out. If the read operation or the write operation is completed or the operation limit timer times out, the control unit 21 determines the condition code m set in the condition code memory 42 as ST37. Then, processing according to the condition code m is executed.

  In the case of the RFID reader / writer 4-1, since the condition code m is “C0”, the processing shown in the flowchart of FIG. 10 is executed. That is, the control unit 21 determines whether or not the read operation or the write operation is normally completed in ST41. When the processing is normally completed, the control unit 21 overwrites the initial frequency memory 43 with the current count value n of the channel counter memory 44 as the next initial frequency k in ST42. Thereafter, the process returns to ST26 and waits for the next command.

  On the other hand, when the read operation or the write operation cannot be normally completed, the control unit 21 increments the count value y of the retry counter memory 46 by “1” as ST43. In ST44, it is determined whether or not the count value y exceeds the set value x stored in the retry count set value memory 45. If the count value y does not exceed the set value x (NO in ST44), the control unit 21 returns to ST30 and performs carrier sense at the frequency of the channel data cnn. An error occurs when the count value y exceeds the set value x.

  Therefore, in the RFID reader / writer 4-1, in which the condition code C0 and the pattern code P5 are set, when a read command or a write command is received, carrier sense is first executed in the radio channel cn4, and a carrier sense error occurs. Carrier sense is performed on the radio channel cn6. Thereafter, the wireless channels are switched in the order of cn5 → cn4 → cn6 → cn5 until an empty channel is detected. If an empty channel is detected, a read operation or a write operation is executed using the empty channel. Thereafter, when the read operation or the write operation ends normally, the used radio channel is stored in the initial frequency memory 43. When the next command is received, carrier sense is started from the previously used radio channel.

  Next, a case where the power of the RFID reader / writer 4-2 is turned on will be described. When the power of the RFID reader / writer 4-2 is turned on, the control unit 21 of the RFID reader / writer 4-2 transmits a setting data inquiry command including the identification code [RWID2] to the store server 2 (ST21). In the store server 2, the condition code C1 and the pattern code P4 corresponding to the identification code [RWID2] are read from the reader / writer setting table 13. Then, channel pattern data [cn9, cn8, cn2, cn1, 0, 0, 0, 0, 0] is created based on the selection order data corresponding to this pattern code P4, and this condition code C1 and channel pattern data [ A setting data response command including cn9, cn8, cn2, cn1, 0, 0, 0, 0, 0] is returned.

  The control unit 21 of the RFID reader / writer 4-2 that has received the setting data response command stores the condition code C1 in the response command in the condition code memory 42 (ST23). Also, channel pattern data [cn9, cn8, cn2, cn1, 0, 0, 0, 0, 0] in the response command is set in the channel pattern table 41 (ST24). Further, the value k in the initial frequency memory is initialized to “1” (ST25). Thereafter, if a read command or a write command is input from POS terminal 1-2 (YES in ST26), control unit 21 switches the radio channel in the order of cn9, cn8, cn2, and cn1 and executes carrier sense (ST30). If an empty channel is detected (NO in ST31), command processing is executed at the frequency of the empty channel (ST35). If the read operation or the write operation is finished or the operation limit timer times out (YES in ST36), the control unit 21 determines the condition code m set in the condition code memory 42 (ST37). Then, processing according to the condition code m is executed.

  In the case of the RFID reader / writer 4-2, since the condition code m is C1, the processing shown in the flowchart of FIG. 11 is executed. That is, the control unit 21 determines whether or not the read operation or the write operation has been normally completed in ST51 (condition determining unit). When the process is normally completed (YES in ST51), the control unit 21 adds a value obtained by adding “1” to the current count value n of the channel counter memory 44 as ST52, and sets the initial frequency memory 43 as the next initial frequency k. Is overwritten (channel switching means). Thereafter, the process returns to ST26 and waits for the next command.

  On the other hand, when the read operation or the write operation cannot be normally completed (NO in ST51), the control unit 21 increments the count value y of the retry counter memory 46 by “1” as ST53. Then, in ST54, it is determined whether or not the count value y has exceeded the set value x stored in the retry count set value memory 45. If the count value y does not exceed the set value x (NO in ST54), the control unit 21 returns to ST30 and performs carrier sense at the frequency of the channel data cnn. An error occurs when the count value y exceeds the set value x.

  Therefore, in the RFID reader / writer 4-2 in which the condition code C1 and the pattern code P4 are set, when a read command or a write command is received, carrier sense is first executed in the channel cn9, and when a carrier sense error occurs, Career sense is executed at cn8. Thereafter, the wireless channels are switched in the order of cn2-> cn1-> cn9-> cn8 until an empty channel is detected. If an empty channel is detected, a read operation or a write operation is executed using the empty channel. When the read operation or the write operation is normally completed, a value obtained by adding “1” to the current count value n of the channel counter memory 44 is overwritten in the initial frequency memory 43 as the next initial frequency k. . Therefore, when the next command is received, the carrier channel is automatically switched to the radio channel next to the previously used radio channel in the same order as in the carrier sense, and the carrier sense is started.

  Next, a case where the RFID reader / writer 4-3 is turned on will be described. When the power of the RFID reader / writer 4-3 is turned on, the control unit 21 of the RFID reader / writer 4-3 transmits a setting data inquiry command including the identification code [RWID3] to the store server 2 (ST21). In the store server 2, the condition code C2 and the pattern code P1 corresponding to the identification code [RWID3] are read from the reader / writer setting table 13. Then, channel pattern data [cn1, cn2, cn3, cn4, cn5, cn6, cn7, cn8, cn9] is created based on the selection order data corresponding to this pattern code P1, and this condition code C2 and channel pattern data [ cn1, cn2, cn3, cn4, cn5, cn6, cn7, cn8, and cn9] are returned.

  Upon receiving the setting data response command, the control unit 21 of the RFID reader / writer 4-3 stores the condition code C2 in the response command in the condition code memory 42 (ST23). Further, the channel pattern data [cn1, cn2, cn3, cn4, cn5, cn6, cn7, cn8, cn9] in the response command is set in the channel pattern table 41 (ST24). Further, the value k in the initial frequency memory is initialized to “1” (ST25). Thereafter, if a read command or a write command is input from the POS terminal 1-3 (YES in ST26), the control unit 21 sets the wireless channels to cn1, cn2, cn3, cn4, cn5, cn6, cn7, cn8, cn9. The carrier sense is executed by switching in order (ST30). If an empty channel is detected (NO in ST31), command processing is executed at the frequency of the empty channel (ST35). If the read operation or the write operation is finished or the operation limit timer times out (YES in ST36), the control unit 21 determines the condition code m set in the condition code memory 42 (ST37). Then, processing according to the condition code m is executed.

  In the case of the RFID reader / writer 4-3, since the condition code m is C2, the processing shown in the flowchart of FIG. 12 is executed. That is, the control unit 21 determines whether or not the read operation or the write operation is normally completed in ST61. When the processing is normally completed (YES in ST61), the control unit 21 overwrites the current count value n of the channel counter memory 44 in ST62 with the initial frequency memory 43 as the next initial frequency k. Thereafter, the process returns to ST26 and waits for the next command.

  On the other hand, when the read operation or the write operation cannot be completed normally (NO in ST61), the control unit 21 determines whether or not the cause of the abnormal termination is a communication error (condition determination) in ST63. means). Incidentally, the communication error is that the response signal from the RFID tag is received and it can be detected that the RFID tag exists in the communication area of the antenna 5-3, but the data stored in the RFID tag is This is a case where a bit missing error or a bit garbled error occurred in the data communication procedure for reading, or it took time for communication and a timeout error occurred in the operation limit timer, and data could not be written normally. .

  If it is caused by a communication error, the control unit 21 proceeds to ST32. That is, the count value n of the channel counter memory 44 is incremented by “1” (channel switching means), and when the count value n exceeds the maximum value “9” of the channel number, the count value n is set to “1”. After returning, it is determined whether or not the channel data cnn of the channel number matching the count value n is “0”. When the channel data cnn is not “0”, the control unit 21 performs carrier sense at the frequency of the channel data cnn. If the channel data cnn is an empty channel, the control unit 21 executes command processing again using the frequency of the empty channel.

  On the other hand, if the error does not result from a communication error, for example, the RFID tag cannot be detected, the control unit 21 increments the count value y of the retry counter memory 46 by “1” as ST64. Then, in ST65, it is determined whether or not the count value y exceeds the set value x stored in the retry count set value memory 45. If the count value y does not exceed the set value x (NO in ST65), the control unit 21 returns to ST30 and executes carrier sense at the frequency of the channel data cnn. An error occurs when the count value y exceeds the set value x.

  Accordingly, in the RFID reader / writer 4-3 in which the condition code C2 and the pattern code P1 are set, when a read command or a write command is received, carrier sense is first executed in the channel cn1, and if a carrier sense error occurs, Career sense is executed at cn2. Thereafter, the wireless channels are switched in the order of cn3 → cn4 → cn5 → cn6 → cn7 → cn8 → cn9 → cn1 → cn2 until an empty channel is detected. Also, when the read operation or write operation does not end normally and the cause is due to a communication error, the use frequency is switched in the same order as in carrier sense, and the read operation or write operation is performed. The operation is re-executed. At this time, since the retry counter memory 46 is not incremented, the operation is repeatedly executed while switching the frequency until it is normally completed.

  Next, a case where the power of the RFID reader / writer 4-4 is turned on will be described. When the power of the RFID reader / writer 4-4 is turned on, the control unit 21 of the RFID reader / writer 4-4 transmits a setting data inquiry command including the identification code [RWID4] to the store server 2 (ST21). In the store server 2, the condition code C0 and the pattern code P3 corresponding to the identification code [RWID4] are read from the reader / writer setting table 13. Then, channel pattern data [cn7, cn9, cn3, cn1, 0, 0, 0, 0, 0] is created based on the selection order data corresponding to this pattern code P3, and this condition code C0 and channel pattern data [ A setting data response command including cn7, cn9, cn3, cn1, 0, 0, 0, 0, 0] is returned.

  The control unit 21 of the RFID reader / writer 4-4 that has received the setting data response command stores the condition code C0 in the response command in the condition code memory 42 (ST23). Also, channel pattern data [cn7, cn9, cn3, cn1, 0, 0, 0, 0, 0] in the response command is set in the channel pattern table 41 (ST24). Further, the value k in the initial frequency memory is initialized to “1” (ST25). Thereafter, if a read command or a write command is input from POS terminal 1-4 (YES in ST26), control unit 21 switches the radio channel in the order of cn7, cn9, cn3, cn1, and executes carrier sense (ST30). If an empty channel is detected (NO in ST31), command processing is executed at the frequency of the empty channel (ST35). If the read operation or the write operation is finished or the operation limit timer times out (YES in ST36), the control unit 21 determines the condition code m set in the condition code memory 42 (ST37). Then, processing according to the condition code m is executed.

  In the case of the RFID reader / writer 4-4, since the condition code m is C0, the processing shown in the flowchart of FIG. 10 is executed. That is, when the read operation or the write operation is normally completed (YES in ST41), the current count value n of the channel counter memory 44 is overwritten in the initial frequency memory 43 as the next initial frequency k (ST42). Thereafter, the process returns to ST26 and waits for the next command.

  On the other hand, when the read operation or the write operation cannot be completed normally, carrier sense is executed at the frequency of the channel data cnn until the count value y of the retry counter memory 46 exceeds the set value x (NO in ST44). . If the count value y exceeds the set value x (YES in ST44), an error is assumed.

  Therefore, in the RFID reader / writer 4-4 in which the condition code C0 and the pattern code P3 are set, when a read command or a write command is received, carrier sense is first executed in the radio channel cn7, and a carrier sense error occurs. Carrier sense is performed on the radio channel cn9. Thereafter, the wireless channels are switched in the order of cn3 → cn1 → cn7 → cn9 until an empty channel is detected. If an empty channel is detected, a read operation or a write operation is executed using the empty channel. Thereafter, when the read operation or the write operation ends normally, the used radio channel is stored in the initial frequency memory 43. When the next command is received, carrier sense is started from the previously used radio channel.

  As described above, according to the present embodiment, the RFID reader / writers 4-1, 4-2, 4-3, and 4-4 have different radio channel switching orders. Therefore, even if a communication error occurs due to the influence of another RFID reader / writer having an adjacent communication area, the communication error can be avoided because each other switches to another radio channel in the next span.

  Further, according to the present embodiment, the number of radio channels to be used can be set for each RFID reader / writer 4-1, 4-2, 4-3, 4-4. Moreover, the conditions for switching the radio frequency can be changed for each RFID reader / writer 4-1, 4-2, 4-3, 4-4. Therefore, communication errors can be avoided more reliably and communication efficiency can be improved.

  Furthermore, according to the present embodiment, each RFID reader / writer 4-1, 4-2, 4-3, 4-4 can individually set radio channel switching condition data. Therefore, since it can be set so that the radio channel is switched under conditions different from those of other RFID readers / writers having adjacent communication areas, communication errors can be avoided more reliably and communication efficiency can be improved. Can do.

The present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage.
For example, in the above-described embodiment, it is determined whether or not the reason why the operation could not be normally terminated as ST63 in FIG. 12 is due to a communication error. Regardless, the radio channel to be used may be switched. However, in this case, even when there is no RFID tag in the antenna communication area, the radio frequency is switched and re-executed. Therefore, in FIG. 12, the processing step of ST63 is deleted and the determination is made in the processing step of ST65. In the case of NO, it is only necessary to proceed to the processing step of ST32.

  In the above embodiment, the reader / writer setting work is executed in the store server 2 in accordance with the procedure shown in the flowchart of FIG. 8, whereby the RFID reader / writer 4-1, 4-4 is read from the reader / writer setting table 13. Although the condition code and pattern code are set for every 2, 4-3, and 4-4, the procedure for setting the condition code and pattern code in the reader / writer setting table 13 is not limited to this. For example, a plurality of patterns of combination data of condition codes and pattern codes are prepared in advance, a system user selects a desired pattern from the plurality of patterns, and each RFID reader / writer 4-1, 4-2. , 4-3, 4-4.

In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, the constituent elements over different embodiments may be combined.
Hereinafter, the invention described in the scope of claims of the present application will be appended.
[Supplementary Note 1] For searching for an empty channel in a wireless communication device that searches for an empty channel from a plurality of wireless channels and performs data communication with a wireless communication medium using the detected empty channel Pattern storage means for storing channel pattern data indicating a wireless channel switching order; and condition storage means for storing the wireless channel switching condition data;
Condition determining means for determining whether or not the switching condition data stored in the condition storage means is satisfied, and if the condition determining means determines that the switching condition data is satisfied, the channel stored in the pattern storage means And a channel switching means for switching a wireless channel in accordance with a pattern data switching order.

[Supplementary Note 2] The wireless communication apparatus according to claim 1, wherein the condition storage means stores condition data indicating when a carrier sense error occurs.

[Supplementary Note 3] The wireless communication according to claim 1, wherein the condition storage means stores condition data indicating execution time of a process according to a command for performing data communication with the wireless communication medium. apparatus.

[Supplementary Note 4] The condition storage means stores condition data indicating that an error has occurred during a data communication procedure with the wireless communication medium after receiving a response signal from the wireless communication medium. The wireless communication apparatus according to claim 1.

[Appendix 5] A wireless communication system comprising a plurality of wireless communication devices according to claim 1, wherein channel pattern data set in the pattern storage means of each wireless communication device and condition data set in the condition storage means A wireless communication system, characterized in that it is different for each wireless communication device.

[Appendix 6] The radio communication system according to claim 5, wherein the condition data stored in the condition storage means of each radio communication device includes condition data indicating the occurrence of a carrier sense error.

[Appendix 7] The condition data stored in the condition storage means of each of the wireless communication devices includes condition data indicating the time of execution of processing corresponding to a command for performing data communication with the wireless communication medium. The wireless communication system according to claim 5.

[Appendix 8] The condition data stored in the condition storage means of each wireless communication device has received a response signal from the wireless communication medium, but an error has occurred in the data communication procedure with the wireless communication medium. 6. The wireless communication system according to claim 5, comprising time condition data.

  1-1, 1-2, 1-3, 1-4 ... POS terminal, 2 ... store server, 4-1, 4-2, 4-3, 4-4 ... RFID reader / writer, 5-1, 5 -2, 5-3, 5-4 ... antenna, 11 ... switching condition table, 12 ... switching pattern table, 13 ... reader / writer setting table, 21 ... control unit, 22 ... storage unit, 23 ... communication unit, 24 ... Timer unit, 25 ... wireless circuit unit, 26 ... carrier sense unit, 41 ... channel pattern table.

Claims (5)

In a wireless communication apparatus that performs wireless communication using an empty channel detected from a plurality of wireless channels between a wireless communication medium including an IC chip and an antenna,
A first table that stores a plurality of types of switching condition data that defines a condition for executing switching of a wireless channel for searching for an empty channel from among the plurality of wireless channels, and switches the plurality of wireless channels in any order Corresponding to the second table for storing a plurality of types of channel switching pattern data that determines whether or not to search for an empty channel and the identification code for identifying the plurality of wireless communication devices, respectively. A third wireless communication device that stores an identification code of another wireless communication device adjacent to the wireless communication device, and the switching condition data and the channel switching pattern data set for the wireless communication device specified by the identification code. A table, and when one wireless communication device is selected from the plurality of wireless communication devices, the selected wireless communication device The identification code of the other wireless communication device adjacent to the device is acquired from the third table, the third table is searched with the acquired identification code, and the switching stored corresponding to the identification code is stored. One of the switching condition data stored in the first table other than the condition data is set in the third table in correspondence with the identification code of the selected wireless communication device, and further the third table 1 of the channel switching pattern data stored in the second table other than the channel switching pattern data stored corresponding to the identification code of the wireless communication device other than the selected wireless communication device. Is connected via a network to a server that sets the third table in the third table in correspondence with the identification code of the selected wireless communication device,
Pattern storage means for receiving and storing channel switching pattern data set in the third table corresponding to its own identification code from the server ;
Condition storage means for receiving and storing the switching condition data set in the third table corresponding to its own identification code from the server ;
In the wireless communication with the wireless communication medium, when the condition of the switching condition data stored in the condition storage unit is satisfied, the channel switching pattern data stored in the pattern storage unit is used to select from among the plurality of wireless channels. Channel switching means for performing switching of radio channels for searching for empty channels,
The wireless communication characterized in that the switching condition data stored by the condition storage means has a switching condition different from that determined by data stored in the condition storage means of another adjacent wireless communication device apparatus. One switch condition data stored in the condition storage means, a wireless communication apparatus according to claim 1, wherein a is as defined the condition that executes switching of the radio channel when the carrier sense error . One switch condition data stored in the condition storage means, according to claim 1 radio, wherein the are as defined the condition that executes switching of the radio channel after the command execution to the wireless communication medium Communication device. One of the switching condition data stored in the condition storage means receives the response signal from the wireless communication medium, but switches the wireless channel when an error occurs in the data communication procedure with the wireless communication medium. radio communication apparatus according to claim 1, wherein a is as defined the condition that execution. The channel switching pattern data stored by the pattern storage unit is different from that determined by the data stored in the pattern storage unit of another adjacent wireless communication device, in that the channel switching pattern is different. Item 5. The wireless communication device according to any one of Items 1 to 4 .

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