KR100730745B1 - Rfid system and controlling method thereof - Google Patents

Abstract

The present invention relates to a radio frequency identification (RFID) system for reading or recording identification information of an RFID tag in a non-contact manner using radio frequency, and more particularly, an RFID reader and a radio frequency consisting of one or more tags. In a recognition (RFID) system, in response to detecting the completion of the question signal transmission of the reader in the standby state, if a command is required to respond, the radio frequency of a predetermined frequency band is emitted to the tag, and the response signal transmission of the tag is completed. In the case of a command related to writing after being sensed, an intelligent power supply device radiates high frequency for a predetermined time and stops radiating high frequency after a predetermined time.

RFID, Tag, Reader, USN, Ubiquitous, High Frequency Radiation, Wireless Power Transmission

Description

Radio Frequency Recognition System and its Control Method {RFID SYSTEM AND CONTROLLING METHOD THEREOF}

1 is a block diagram showing the basic configuration of an RFID system according to the prior art.

2 is a block diagram showing the operation of the RFID system according to the prior art.

Figure 3 is a block diagram showing another embodiment of a radio frequency identification system according to the prior art.

4 is a block diagram showing an embodiment of an RFID system according to the present invention;

FIG. 5 is a diagram illustrating a format of a question signal shown in FIG. 4.

FIG. 6 is a diagram illustrating a format of a response signal shown in FIG. 4.

7 is a block diagram showing in detail the configuration of the RFID system according to the present invention.

8 is a detailed flowchart illustrating a control process of the RFID system according to the present invention.

<Description of Symbols for Main Parts of Drawings>

100: radio frequency recognition system 10: reader

50: tag 70: intelligent power supply

11 transmitter 12 receiver

13: frequency synthesizer 14: processor

15: antenna 51: semiconductor IC

53: RF circuit 54: control logic

56 antenna 71 receiver

72: reception antenna 73: control unit

75: high frequency generation unit 77: antenna for transmission

The present invention relates to a radio frequency identification (RFID) system that reads or records identification information of an RFID tag in a non-contact manner using radio frequency, and more particularly, intercepts communication contents between the reader and the tag. Intelligent power that radiates high frequency to tag when response request command is included after transmission of question signal is completed, and generates high frequency for a predetermined time when write command is included after response signal transmission is completed, and stops radio frequency radiation after a predetermined time elapses The present invention relates to a radio frequency identification system including a supply device and a control method thereof.

In general, Radio Frequency IDentification (RFID) inputs identification information unique to the smallest IC chip and uses RF to recognize, track, and manage objects, animals, and people to which the chip is attached. Speak skills you can. Such an RFID system is composed of an RFID tag (Tag or Transponder) to which unique identification information is input and attached to an object or animal, and a reader (Reader or Interrogator) for reading or writing contact information of the tag without contact. An information processing apparatus such as a computer is connected to the reader to process data collected from a tag.

1 is a block diagram showing the basic configuration of an RFID system according to the prior art. As shown, the tag 5 is a passive tag which does not have a power supply by itself, and is composed of a small semiconductor IC chip and an antenna, in which an RF circuit, logic, and memory are embedded. These tags 5 have various sizes and shapes. The reader 1 includes a transmitter for transmitting an RF signal of a specific frequency band to the tag 5, a receiver for receiving a signal transmitted from the tag 5, and an antenna for transmitting and receiving the signal.

2 is a block diagram showing the basic operation of the RFID system according to the prior art. As shown, the reader 1 transmits an RF signal of a predetermined frequency band including a high frequency carrier signal and a predetermined question signal. When the tag 5 is located in the electromagnetic field of the reader 1 formed by the RF signal, the tag 5 supplies the operating power required to operate the IC chip from the high frequency carrier CW signal of the reader 1. Receive. That is, the high frequency carrier signal transmitted from the reader 1 generates AC in the antenna of the tag, and the generated AC is rectified and used as electric energy for the IC chip. In addition, the tag 5 modulates the received RF signal and reflects the data stored in the tag 5 based on the received RF signal, and transmits the response signal to the reader 1 as a response signal. As described above, the conventional RFID system performs power transmission for activating a passive tag as well as information transmission between the reader 1 and the tag 5.

In general, a passive tag that does not have its own power source has a shorter recognition distance of less than 1 m. Therefore, a low frequency (125 kHz, 12.56 MHz) short range RFID system is mainly used. These short range RFID systems transmit power and signals by the multi-wound coils of the reader, and the tags receive power energy generation and signals by a magnetic coupling method by magnetic fields of alternating current flowing through the coils of the reader. Therefore, the conventional low frequency RFID system using a passive tag has been used for a limited purpose, such as logistics management, access management and transportation cards because the recognition distance of the tag is short.

On the other hand, active tags, which can read / write and combine sensors, enable history management and environmental information sensing, and have a long recognition distance. Therefore, these active tags are difficult to miniaturize, are expensive, and their service life is limited by power supply life.

Recently, standardization of passive RFID technology using electromagnetic waves and reflection modulation (Backscattered Modulation) in the UHF (860 to 960 MHz, 2.4 GHz) band is progressing. Accordingly, the recognition distance of the passive tag is expected to increase by about 4m. Theoretically, if the reader's transmit power is increased and the tag's antenna is increased, the communication distance between the tag and the reader can be further increased. However, when the transmission power of the reader increases, it causes a problem of frequency interference between adjacent readers and between the reader and the existing wireless communication service. In particular, when the RFID reader is embedded in a personal mobile communication terminal, the interference problem between readers is likely to deepen. In addition, the larger the antenna of the tag, the smaller the size becomes difficult.

Furthermore, in the future, RFID tag will detect the environmental information (temperature, humidity, pollution information, crack information, etc.) of the surrounding environment by adding the sensing function from the passive type that simply transmits the identification (ID) information according to the reader's request. It is expected to develop into a ubiquitous sensor (u sensor) that actively delivers to the network. In addition, Ubiquitous Sensor Network (USN) attaches micro tags to not only objects such as street poles, sidewalks, walls and floors of buildings, but also to animals and people (Ubiquitous), It collects information in real time using a mobile wireless reader that is present and delivers the collected information to the network.

Therefore, in order to build a ubiquitous sensor network (USN), development of low-cost, high-performance, ultra-solid tags is required. This USN tag (u-sensor) should be highly functional and have a long recognition distance because it is inexpensive and small enough to be installed anywhere, combined with sensing functions, and capable of processing a large amount of information.

However, in order to process many functions of the tag and to make the recognition distance long enough, power consumption increases. For example, receiving / decrypting and operating commands from a reader requires several microwatts (microwatts) of power, while the tag backscatters a response to the command back to the reader and tens of microwatts (microwatts). ) Power consumption is required. Therefore, such a tag requires continuous power supply and has its own battery, making it difficult to reduce the thickness of the tag.

3 is a configuration diagram showing another configuration example of the RFID system according to the prior art, in order to provide power consumption of such a tag, as shown in FIG. 3, by intercepting communication between the reader 1 and the tag 5. When the question signal transmission of the RF signal f1 of the reader 1 is completed, there is a technique of radiating to the tag 5 a high frequency, which is a high output power transmission that is activated by the reader 1 and does not have information related to communication. The RF shower system 7 technology is disclosed in detail in Korean Patent Publication Nos. 05-11236 and 05-11211.

However, this technology transmits a command for turning on the radio frequency radiator 7 from the reader after completion of the question signal transmission, which is the RF signal f1 radiated from the reader 1 to the tag 5, and according to this command, The radio frequency of the radiator 7 is radiated to the tag 5, and the tag 5 transmits a response signal to the RF signal f1 of the tag after reception of the high frequency. In this case, when the frequency and the protocol between the reader and the high-frequency radiator are the same as the frequency and protocol between the reader and the tag communication, communication errors occur, and hardware and software become complicated when using different frequencies and protocols.

The present invention has been made to solve the problems of the RFID system according to the prior art, and the main object of the present invention is to tag the high frequency of the intelligent power supply device when a response request command is included after the transmission of the interrogator signal. Radiate, and if the write command is included after the completion of the response signal transmission, by adding an intelligent power supply that transmits high frequency to the tag for a predetermined time and stops radiating high frequency after a predetermined time, the response distance is increased or the power level of the reader is increased. The present invention provides a radio frequency identification system and a method of controlling the same.

In order to achieve the above object of the present invention, the radio frequency identification system according to the present invention, in a radio frequency identification (RFID) system consisting of an RFID reader and one or more tags, detecting that the question signal transmission of the reader is completed When the response request command is included, the radio frequency of the predetermined frequency band is radiated to the tag.If the response signal of the tag is detected, the radio signal is radiated for a predetermined time. Characterized in that configured to include an intelligent power supply to stop.

The intelligent power supply device receives the RF signal transmitted from the reader, a receiving unit for receiving and processing an RF signal, a receiving antenna, a high frequency generator operated by an external power source, and detects that the interrogation signal of the reader is completed. After the response request command is included, the radio frequency of the predetermined frequency band is radiated to the tag, and if the write command is detected after the response signal transmission of the tag is detected, the radio frequency is radiated for a predetermined time. The control unit for stopping the radiation of the transmission, and a transmission antenna for processing the high frequency of the control unit to radiate to the tag.

In the above-described method for controlling a radio frequency identification system for low power reader-tag communication according to the present invention, a radio frequency identification system including an RFID reader, at least one tag, and an intelligent power supply device, a) RF signal of the reader Receiving and storing a question mark; b) checking that the question signal transmission is completed and radiating a high frequency of a predetermined frequency band to a tag when the RF signal transmission is completed and supplying operation power of the tag; c) transmitting a response signal by receiving a question signal from the reader and modulating the RF signal received from the reader to send information stored therein; And d) detecting completion of the response signal transmission, and if the write command is included, radiating high frequency for a predetermined time and then stopping high frequency radiation.

(Example)

 Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the radio frequency identification system according to the present invention.

First, Figure 4 is a block diagram showing an embodiment of an RFID system according to the present invention. As illustrated, the RFID system 100 according to the present embodiment uses a reader 10 that transmits and receives an RF signal and a RF signal of a specific frequency band transmitted by the reader 10 in a backscatterd modulation scheme. When the tag 50 transmitting information owned by the reader and the completion of the question signal transmission of the reader are detected, and a response request command is included, the tag 50 radiates a high frequency of a predetermined frequency band to the tag, and the response signal transmission of the tag is completed. When the detected write command is included, the intelligent power supply 70 emits high frequency for a predetermined time and stops radiating high frequency after a predetermined time.

Here, when the communication protocol used in the radio frequency identification system is ISO-18000 type B, the intelligent power supply device 70 includes a preamble code and a delimit included in the interrogation signal of the RF signal f1 of the reader 10. When a 3/2 bit frame is received continuously after receiving the code, it is determined that the question signal transmission is completed.

It is similarly operated even when the communication protocol used in the above-mentioned radio frequency identification system is not used.

On the other hand, if the question signal includes Start of Frame (SOF) and End of Frame (EOF), it is determined that the question signal transmission is completed by detecting the SOF and EOF.

Here, the high frequency (microwave) of the predetermined frequency band is the same as the RF signal of the reader 10, except that it does not have any information to transmit power wirelessly to the tag 50.

Therefore, the reader 10 and the tag 50 are wirelessly communicated using the RF signal of a specific frequency band. The intelligent power supply device 70 wirelessly supplies power to the tag 50 through a high frequency of a predetermined frequency band. Here, the RF signal means a high frequency wave containing information such as a question signal and a response signal, and the high frequency wave means pure continuous wave (CW) that does not contain any information. As described above, the RFID system 100 according to the present exemplary embodiment emits a high frequency when the question signal includes a response request command after completion of the transmission of the question signal, compared to the conventional RFID system 1, and after completion of the response signal transmission. If the write command is included, the intelligent power supply 70 for stopping the high frequency radiation after a high frequency radiation for a predetermined time is further included. In addition, since the intelligent power supply device 70 radiates high frequency to the tag 50, no artificial power transmission is necessary between the reader 10 and the tag 50 or the recognition distance becomes long when an existing reader is used. In other words, the radiation power of the reader is lowered.

5 is a view illustrating a transmission format of an interrogation signal of the ISO-18000 type B protocol applied to an embodiment of the present invention, and FIG. 6 is a diagram of a interrogation signal of the ISO-18000 type B protocol applied to an embodiment of the present invention. Figure shows the transmission format. As shown, the question signal includes a preamble detect code for transmitting a continuous wave (CW) of about 400 Hz, a preamble code for indicating the start of the picket, and a delimiter for determining the data ratio of the response signal. Code, a command code indicating a type of command, a parameter code, a data code, and a cycle redundancy check (CRC) -16 code for detecting a data transmission error.

In addition, the response signal transmitted from the tag in response to the question signal includes a 400 kHz stop code, a return preamble code, a data code, and a CRC-16 code to which the tag does not respond. The stop code transmission time is 400 ms for ISO 18000-6 type B. This stop code transmission time is variable and ranges from 85 to 460 ms depending on the delimiter and error.

7 is a block diagram showing in more detail the structure of the reader 10, the tag 50 and the intelligent power supply 70 that can be applied to the RFID system according to the present invention. However, the illustrated configuration is only schematically shown to aid the understanding of the present invention, and these configurations are not only easily understood by those skilled in the art, but also easily added, deleted, and modified in part as necessary, and the technical spirit of the present invention. Since it is possible to achieve the scope of the present invention is not limited to the illustrated example.

As shown therein, the RFID system 100 according to the present invention includes a reader 10, a passive tag 50, and an intelligent power supply 70. First, the reader 10 is the same as or similar to the conventional configuration, and includes a transmitter 11 for modulating and transmitting an RF signal, a receiver 12 for demodulating and receiving a received RF signal, and oscillating a predetermined carrier. And a frequency synthesizer 13, and a processor 14 for processing a received or transmitted signal. The RF signal including the question signal is received and transmitted through the high frequency antenna 15.

The tag 50 is also the same as or similar to a conventional passive tag, and is composed of a semiconductor IC chip 51 having a RF circuit 53, a control logic 54, and a memory 55 and a high frequency antenna 56. . In this case, the antenna 56 is a dipole antenna, which is a rectenna in which a rectifier 56 is combined. The antenna 56 has a structure in which a rectifier diode is connected to the center of a 1/2 wavelength dipole antenna. Accordingly, the antenna 56 may receive the electromagnetic wave radiated from the intelligent power supply device 70 and convert it into electrical energy (direct current).

Subsequently, the intelligent power supply device 70 includes a receiving unit 71 and a receiving antenna 72 for receiving and processing a question signal, which is an RF signal, in a standby state, and a high frequency generating unit 73 operated by an external power source. And the RF signal transmitted from the reader 10 to detect the completion of the transmission of the question signal supplied from the reader 10 to the tag 50 and only to include the response request command in the question signal. When a high frequency of a predetermined frequency band generated by the generator 73 is radiated to the tag 50 and the response signal transmitted from the tag 50 to the reader 10 is sensed to be completed and a write command is included, it is set in advance. And a control unit 75 for stopping the high frequency radiation after the predetermined time radiation, and a transmitting antenna 78 for processing the high frequency of the control unit 75 to radiate the tag 50 to the tag 50.

When the communication protocol is ISO 18000 type B, when the communication protocol is continuously received for more than 3/2 bit frames after receiving a preamble code and a delimiter code indicating the start of the picket included in the interrogation signal. It is determined that the question signal transmission is completed, and the response signal transmission completion is determined according to whether the response signal has been received for a predetermined time. The predetermined time is a stop code (quiet) transmission time and the response signal transmission time contained in the response signal. Here, the stop code is varied according to the data ratio set by the delimiter code of the interrogation signal, and the stop code transmission time is 85-460 ms in the case of ISO 18000-6 type B. If the response signal is not received after the predetermined time, the controller 73 determines that the response signal is transmitted. That is, if there is no response, the predetermined time is a response to transmit turnaround time after reception, and is about 85-460 kHz.

According to the present invention, the reader 10 generates a plurality of carrier signals from a phase locked loop (PLL) frequency synthesizer 13 to transmit predetermined information (question signal) and uses the FHSS or AFA-LBT method to set a frequency of use. Choose. The channel connection (selection) method is a method of determining a channel frequency that the reader 10 can occupy at a specific time regardless of the FRID communication method, and is used to avoid external interference or to prevent external interference during communication. Because it is a technology, it is decided according to the radio regulations of each country. Subsequently, the modulator of the transmitter 11 generates a modulated signal, and the modulated signal is amplified and passed through a filter to the tag 50 and the intelligent power supply 70 through the antenna 15.

Subsequently, the interrogation signal of the reader 10 of the selected use frequency is transmitted to the control unit 73 through the receiving unit 71 and the antenna 72 of the intelligent power supply device 70 in the standby state, and the intelligent power supply device ( The control unit 73 of 70 determines the completion of the question signal transmission according to the received question signal, and generates a high frequency of a predetermined frequency band through the high frequency generator 75 according to the determination result, and continuously through the antenna 77. To emit. In addition, the tag 50 located in the radiation area Ra of the intelligent power supply 70 receives the high frequency radiated by the intelligent power supply 70 and transmits high frequency AC through the rectine dipole antenna 55. The power is rectified and multiplied to use the RF circuit 53, the control logic 54, and the memory 55 as a power source for operation.

The tag 50 reflects and modulates the RF signal f1 to the reader 10 and the intelligent power supply device 70 to backscatter the response signal to the command transmitted from the reader 10. The reader 10 demodulates the reflection modulated RF signal f1 and provides the collected information to a computer or a host server through a network (not shown).

On the other hand, the control unit 73 of the intelligent power supply device 70 determines that the response signal transmission received through the receiving unit 71 and the receiving antenna 72 is completed to radiate high frequency radiation of the high frequency generator 73. Stop.

FIG. 8 is a flowchart for describing an operation process of the controller illustrated in FIG. 5. As shown in the drawing, first, the controller 73 of the intelligent power supply 70 is activated by an external power source to maintain a standby state. (Step 301).

Subsequently, the control unit 73 of the intelligent power supply device 70 receives a command included in the RF signal f1 transmitted from the reader 10 to the tag 50 (step 305), and the command (RF signal) It is checked whether the transmission of the question signal of f1) is completed (step 307).

In step 307, a command of 3/2 bit frame or more is continuously received after receiving a preamble code and a delimiter code indicating the start of the picket included in the interrogation signal in case of the ISO 18000 type B protocol. If so, it is determined that the question signal transmission is completed.

When the transmission of the command is completed through the step 307, the control unit 73 of the intelligent power supply device 70 checks whether the response request command included in the question signal is included (step 308), and the response request command is When included, the high frequency generated from the high frequency generator 75 radiates to the tag 50 through the antenna for transmission (step 309. In this case, the high frequency of the predetermined frequency band radiated by the intelligent power supply device 70) Since no information is included, information exchange (communication) does not occur between the tag 50 and the intelligent power supply 70. As such, the information is located within the radiation area Ra of the intelligent power supply 70. The tag 50 is placed in a standby state where power is supplied.

Subsequently, the tag 50 is activated by the radiated high frequency to transmit a response signal for responding to the command of the reader 10 to the reader 10 and the intelligent power supply 70 (step 311).

The receiving unit 71 and the antenna 72 of the intelligent power supply device 70 receive and process a response signal, transmit the response signal to the control unit 73, and the control unit 73 checks whether a predetermined time response signal is received. To determine the completion of the response signal transmission (step 313).

The step 313 determines whether the response signal transmission is completed according to whether a response signal has been received for a predetermined time, wherein the predetermined time is a stop code transmission time included in the response signal and a response signal transmission time of the tag. If the response signal is not received after the predetermined time, the predetermined time is a response to transmit turnaround time (about 85-460 kHz). When the predetermined time has elapsed, the controller 73 determines that the response signal is transmitted.

After that, the controller 73 checks whether a write command is included (step 314), and if a write command is included, radiates high frequency for a predetermined time (step 315), and after a predetermined time (step 316), radiates high frequency. Stop (step 317).

According to an embodiment of the present invention, the tag 50 transmits information including identification (ID) information by using a Backscatterd Modulation method using an RF signal f1 of a specific frequency band. The sensor may be combined with the above sensor, and the reader 10 is described as being installed in a predetermined region, but may be embedded in the mobile terminal. When a reader is embedded in the mobile terminal, information processed by the reader 10 is provided to a mobile communication terminal, a computer, or a host server (not shown) through an existing wireless network to form a predetermined ubiquitous sensor network (USN). Done.

As described above, the radio frequency recognition system and control method according to the present invention, after detecting the completion of the question signal transmission of the reader by the intelligent power supply device emits a high frequency to the tag when a response request command is included, When a write command is included after completion of the response signal transmission, the high frequency radiation is stopped after the high frequency radiation for a predetermined time, thereby increasing the response distance of the tag and reducing the power level of the reader. It also has the advantage that it can be applied without modifying the protocol, software and hardware of the existing tags and readers at all compared with similar existing inventions.

As such, those skilled in the art to which the present invention pertains will understand that the present invention may be embodied in other specific forms without changing to the technical spirit or essential features of the present invention. Therefore, the above-described embodiments are to be understood in all respects as illustrative and not restrictive. The scope of the present invention is shown by the following claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. .

Claims (15)

In a RFID reader and a radio frequency identification (RFID) system consisting of one or more tags, After detecting the completion of the question signal transmission of the reader, if a response request command is included, radiates a high frequency of a predetermined frequency band to the tag, and if a write command is included after detecting that the response signal of the tag is completed, the high frequency for a predetermined time Radio frequency recognition system comprising an intelligent power supply for emitting radiation and stop the emission of high frequency after a predetermined time. The radio frequency recognition of claim 1, wherein the intelligent power supply device receives a start of frame (SOF) and an end of frame (EOF) included in the RF signal to determine whether the question signal transmission is completed. system. The system of claim 1, wherein the intelligent power supply device determines that the question signal is transmitted when a predetermined bit or more is continuously received after receiving the preamble code and the delimit code included in the RF signal. 4. The system of claim 3, wherein the predetermined bit is at least 3/2 bit frames. The system of claim 1, wherein the intelligent power supply is determined to transmit a response signal when there is no response of the tag until a predetermined time elapses. 6. The system of claim 5, wherein the predetermined time is a stop code transmission time and a response signal transmission time included in the response signal. 6. The system of claim 5, wherein the predetermined time is a response to transmit turnaround time after reception if there is no response. The method of claim 1, wherein the intelligent power supply, A receiving unit and a receiving antenna capable of maintaining a standby state, A high frequency generator operated by an external power source, The RF signal transmitted from the reader is processed to emit a high frequency signal of a predetermined frequency band generated by the high frequency generator when a question signal transmitted from the reader to the tag is completed and a response request command of the question signal is detected. A control unit which stops the high frequency radiation after a predetermined time high frequency radiation when a response signal transmitted from the tag to the reader is completed and a write command is detected; A radio frequency recognition system comprising a transmitting antenna for processing a high frequency of the control unit to emit a tag. In a control method of a radio frequency identification system consisting of an RFID reader, at least one tag and an intelligent power supply, a) the intelligent power supply device receives and stores the RF signal of the reader; b) the intelligent power supply device checks that the RF signal transmission is completed, and when the RF signal transmission is completed and the response request command is included in the RF signal, radiates a high frequency of a predetermined frequency band to a tag to supply operating power of a tag. Doing; c) transmitting a response signal by receiving a question signal from the reader and modulating the RF signal received from the reader to send information stored therein; And and d) stopping the high frequency radiation after the high frequency radiation for a predetermined time when the intelligent power supply device detects that the response signal is transmitted and the write command is completed. 10. The method of claim 9, wherein the step b) comprises: receiving a start frame (SOF) and an end frame (EOF) included in the RF signal to determine whether the question signal transmission is completed. How to control the system. 10. The method of claim 9, wherein when the command code of a predetermined bit or more is continuously received after receiving the preamble code and the delimit code included in the RF signal, it is determined that the transmission of the question signal is completed. 12. The method of claim 11, wherein the predetermined bit is greater than or equal to 3/2 bit frame. The radio frequency identification system according to claim 9, wherein step d) is determined that response signal transmission is completed when a predetermined time elapses. The method of claim 13, wherein the predetermined time is a stop code transmission time and a response signal transmission time included in the response signal. The method of claim 13, wherein the predetermined time is a response to transmit turnaround time after reception if there is no response.

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