KR20080019096A - Low power rfid system and method, reader applied to the same - Google Patents

Abstract

A system and a method for low power RFID(Radio Frequency Identification) and a reader applied to the same are provided to set a power mode actively according to radio wave environment received by a reader performing RFID communication with a predetermined tag, thereby increasing an operation time of the reader and manufacturing a smaller reader by using small battery capacity. In an RFID system by wireless communication between a reader(100) and a tag(200), the reader determines an RFID distance as an actual survey distance with the tag through a size of an RF signal received from the tag. By comparing the determined RFID distance with a preset reference distance, the reader is operated in a high power mode or low power mode according to the comparison result.

Description

LOW POWER RFID FREQUENCY RECOGNITION SYSTEM AND METHOD AND READER APPLIED TO LOW POWER RFID SYSTEM AND METHOD, READER APPLIED TO THE SAME

1 is a block diagram showing a radio frequency identification system according to the prior art,

2 is a block diagram showing a low power radio frequency identification system according to an embodiment of the present invention;

3 is a block diagram showing the internal configuration of the leader shown in FIG.

FIG. 4 is a flowchart illustrating an operation of the low power radio frequency identification system shown in FIG. 2.

<Description of Symbols for Main Parts of Drawings>

100: reader 110: receiving unit

111, 148, 210: Antenna 112, 147: Bandpass filter

113: low noise amplifier 114: automatic gain control amplifier

120: signal processor 121: first frequency generator

122: Nth frequency generator 123: First phase locked loop circuit

124: Nth phase locked loop circuit 125: First switch

126: Nth switch 127: First mixer

128: phase shifter 129: second mixer

130 control unit 140 transmission unit

141: first mixer 142: second mixer

143: drive amplifier 144: switch

145: power amplifier 146: drive amplifier

200: tag 220: electronic chip

The present invention relates to a low-power radio frequency identification system and method, and more particularly, to increase power efficiency of a reader by manually or automatically turning on or off a power amplifier according to a radio wave environment in which a reader using a power amplifier is in short-range wireless communication. The present invention relates to a low power radio frequency identification system and method and a reader applied thereto.

In general, Radio Frequency IDentification (RFID) inputs identification information unique to the smallest IC chip and uses RF to recognize, track, and manage the object or animal to which the chip is attached. Says technology. 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) to read or write the identification 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 20 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, and the IC chip has RF circuits, logic, and memory embedded therein. These tags 20 have various sizes and shapes. And the reader 10 is configured to include a transmitter for transmitting the RF signal of a specific frequency band to the tag 20, a receiver for receiving a signal from the tag 20 and an antenna for transmitting and receiving it.

As described above, in the conventional RFID system, power transmission for activating a passive tag as well as information transmission is performed between the reader 10 and the tag 20.

That is, since the reader needs to supply the energy necessary to operate the tag, the transmission power of the reader should be greatly increased in order to secure sufficient recognition distance and achieve a high function. there was. In addition, since the UHF reader applied in the Ultra High Frequency (UHF) band of 300 MHz to 3,000 MHz has a power amplifier, a method for performing a reader function for a longer period of time is required due to the increased power consumption.

Therefore, the present invention was created to solve the above problems, and an object of the present invention is to actively adjust the power mode of the reader according to the radio wave environment received by the reader in real time displacement in the wireless communication process by the RF recognition method. To provide a low power radio frequency identification system and method and a reader applied thereto.

In the low power radio frequency identification system according to the first aspect of the present invention for achieving the above object, the reader is a radio frequency identification (RFID) which is a measured distance from the tag through the magnitude of the RF signal received from the tag. The apparatus may determine a recognition distance and operate in a high power mode or a low power mode according to a result generated by comparing the determined RFID recognition distance with a preset reference distance.

In addition, the low-power radio frequency identification system according to a second aspect of the present invention for achieving the above object, the reader determines the RF ID recognition distance of the measured distance with the tag through the size of the RF signal received from the tag and The variable control high power mode or the low power mode is operated according to a result generated by comparing the determined ID recognition distance with a predetermined reference distance or whether the tag is recognized. The variable control high power mode is a tag recognition in the low power mode of the reader. When an error occurs, it is a mode for transmitting a high output signal generated by variably controlling the power amplification rate according to the size of the RF signal.

In addition, the reader according to the third aspect of the present invention for achieving the above object, and determines the power size of the RF signal received by the power transmission to the tag, the RFID identification with the tag according to the power size of the RF signal Set the distance, and operate in a high power mode or a low power mode according to the result generated by comparing the RF ID recognition distance and the predetermined reference distance, if the tag recognition is not made through the feedback RF signal received in the low power mode step by step It is characterized by switching to a variable control high power mode to variably control the power amplification rate.

In addition, the low power radio frequency identification method according to the fourth aspect of the present invention for achieving the above object, (a) the reader receives the RF signal from the tag, (b) the power mode setting of the reader is manual Or (c) if the power mode of the reader is automatically set, determining the RF signal size to set an RFID ID distance with the tag, and setting the RFID ID distance with the set RFID ID. Comparing the preset reference distance, (d) operating in a high power mode or a low power mode according to a result generated by comparing the set RFID recognition distance with a preset reference distance; and (e) the high power mode or low power. Transmitting a high output signal or a low output signal generated by a real-time displacement through a reader operating in a mode to the tag. It features.

In addition, the low-power radio frequency identification method according to the fifth aspect of the present invention for achieving the above object, a) receiving an RF signal from the tag that the reader operates by power transmission, (b) the power of the reader Checking whether the mode setting is manual or automatic; (c) if the power mode of the reader is set to manual, automatically switching to a high power mode if the reception rate for the RF signal is weak; and (d) entering the high power mode. And transmitting the high output signal generated by the operating reader to the tag.

In addition, a low power radio frequency identification method according to a sixth aspect of the present invention for achieving the above object, (a) the reader receives an RF signal or a feedback RF signal from the tag, (b) the Checking whether the power mode setting is manual or automatic; (c) if the reader's power mode is automatically set, determining an RFID ID distance from the tag through the magnitude of the RF signal or the feedback RF signal; Comparing the set RFID recognition distance with a preset reference distance; (d) determining whether the tag is recognized or not; (e) comparing the set RFID recognition distance with the preset reference distance; Operating in a variable control high power mode or a low power mode according to the generated result or tag recognition; and (g) the variable control high power mode or low power. And transmitting the variable control high output signal or low output signal generated by the real time displacement to the tag through the reader operating in the output mode.

In addition, the low power radio frequency identification method according to the seventh aspect of the present invention for achieving the above object, (A) the reader receives the RF signal from the tag, (B) the power mode setting of the reader is manual Or (c) determining whether the RFID ID recognition distance with the tag is determined based on the size of the RF signal when the power mode of the reader is automatically set. Comparing the set reference distances, (d) operating in a high power mode or a low power mode according to a result generated by comparing the set RFID recognition distance with a preset reference distance, and (e) in the low power mode operation state. If the tag recognition is not made, the step of switching to the variable control high power mode for variable control of the power amplification step by step and Through the reader operating in the high power mode control is characterized in that it comprises the step of transmitting power amplifying a high-output variable control signal in response to the power amplification factor in the tag.

Hereinafter, a preferred embodiment of a low power radio frequency identification system according to the present invention with reference to the accompanying drawings in more detail.

2 is a block diagram illustrating a low power radio frequency identification (RFID) system according to an embodiment of the present invention. As shown in FIG. 2, the low power RF recognition system uses a reader 100 for transmitting and receiving an RF signal and a RF signal of a specific frequency band transmitted by the reader 100 in a backscatterd modulation scheme. It consists of a tag 200 for transmitting the information it has. The tag 200 is implemented with an antenna 210 for wireless communication with the reader 100 and an electronic chip 220 for storing predetermined information in response to a question signal of the reader 100. Further, the reader 100 executes power transmission for operating the tag 200 to communicate with the tag 200 through the power magnitude of the RF signal received from the tag 200. IDentification) determines a recognition distance, compares the determined RFID recognition distance with a preset reference distance, generates a predetermined result, and sets the high power mode or the low power mode of the reader 100 according to the generated result. .

In addition, as the reader 100 receives the related RF signal in real time while the RFID 200 wirelessly communicates with the tag 200, the RFID recognition distance also changes in response to the RF signal received by the displacement in real time. The result generated by comparing the RFID recognition distance with the reference distance also changes in real time. Therefore, the reader 100 switches the high power mode or the low power mode by the RFID recognition distance to transmit the high output signal or the low output signal to the tag 200.

For a more detailed description, reference is made to FIG. 3 which shows a detailed configuration of a reader 100 for implementing a low power radio frequency identification system. In order to implement active power mode switching of the reader 100, an internal configuration may be implemented in various ways, and a low power radio frequency identification system implemented in the configuration of the reader 100 described below is more preferable.

As shown in FIG. 3, the reader 100 transmits power to the tag 200 through the antenna 111, and the received tag 200 operates to transmit in response to the question signal of the reader 100. Receiving unit 110 for receiving an RF signal, a signal in which a coherent frequency channel is synchronized with the communication frequency of the RF signal which is the output signal of the receiving unit 110 and the RF signal which is the output signal of the receiving unit 110 Determining the RF ID recognition distance between the reader 100 and the tag 200 through the signal processing unit 120 to provide to the control unit 130, the magnitude of the RF signal, the determined RF ID recognition distance and the preset The controller 130 sets a high power mode or a low power mode according to the result generated by comparing the reference distances, and generates a frequency selection signal for selecting a frequency channel corresponding to the set mode and the signal processing based on the frequency selection signal. Power tag or drive amplified output signal from the control unit 130 through the frequency channel switched in the unit 120 according to the switching switching signal of the control unit 130 to the tag 200 through the antenna 148 It includes a transmitter 140 for transmitting to.

The receiver 110 may include a band pass filter 112 for passing an RF signal of a predetermined frequency band of the reader 100 and a low noise amplifier 113 for removing noise components of an output signal of the band pass filter 112. And an automatic gain control amplifier 114 for maintaining the power level of the output signal of the low noise amplifier 113 at a constant level.

In addition, the signal processing unit 120 is based on the frequency output from the at least one frequency generator (121, 122), the frequency generator (121, 122) for generating a frequency of various frequency bands for RF ID wireless communication, respectively It is connected to an output terminal of the phase locked loop circuits 123 and 124 and the phase locked loop circuits 123 and 124 for generating a predetermined frequency, which is phase locked, and switching according to the frequency selection signal of the controller 130. At least one switch 125 and 126 for transmitting the output signal of the phase locked loop circuits 123 and 124 through a frequency channel coherent to the communication frequency of the RF signal, which is the output signal of the receiver 110, and the receiver 110. A first mixer 127 for mixing the output signal of the switch and the output signals of the switches 125 and 126 switched in the on state and transmitting the mixed signal to the controller 130 and the switch 12 switched in the on state. And a second mixer 129 for mixing the output signal of the 5, 126 phase shifted by 90 degrees and the output signal of the receiver 110 to transmit the mixed signal to the controller 130.

Further, the controller 130 determines the power level of the RF signal, which is an output signal of the receiver 110 applied through the first mixer 127 provided in the signal processor 120, and thus the reader 100 and the tag 200. ) If the RFID ID recognition distance is set, and if the RFID recognition distance is greater than or equal to the preset reference distance, the reader 100 is set to operate in a high power mode. If the RFID ID recognition distance is less than the preset reference distance, the RFID ID is set to low power mode. Operation of the reader 100 is set. In addition, the controller 130 is provided with at least one of a conventional microprocessor, a digital signal processor (DSP), an analog control circuit, or a dedicated digital signal processing hardware.

In addition, when setting the reader 100 in the high power mode, the controller 130 determines a frequency channel corresponding to the high power mode, generates a frequency selection signal for the determination result, and transmits the signal to the signal processor 120. The frequency channel signal formed by the signal processor 120 is applied and transmitted to the transmitter 140 as an output signal, and the switching unit 140 transmits a switching switching signal for setting a high power mode so that the frequency channel is transmitted by the transmitter 140. Power amplification of the output signal of the controller 130 due to the signal.

In the meantime, when the reader 100 operates in the low power mode, the controller 130 determines a frequency channel corresponding to the low power mode, generates a frequency selection signal for the determination result, and transmits the frequency selection signal to the signal processor 120. Receives the frequency channel signal formed by the signal processing unit 120 and transmits it to the transmitter 140 as an output signal, and transmits the switching switching signal for the low power mode to the transmitter 140 to output the signal due to the frequency channel signal Drive amplification.

In addition, the above-mentioned reference distance is for selecting the high power mode or the low power mode of the reader 100 in response to the RF ID recognition distance, and is a value set within a few centimeters to several tens centimeters of the RF near field communication distance. . In general, the reference distance is preferably set to a value within 1 meter, but since the reference distance is used as a reference for selecting a high power mode or a low power mode in order to efficiently manage the power of a reader, Do not.

Furthermore, the transmitter 140 of the reader 100 collects and outputs the output signals of the switches 125 and 126 switched and switched on by the signal processor 120 and the output signals of the controller 130. (141), a second output signal obtained by combining the output signal of the switches 125 and 126 switched to the on state by 90 degrees through the phase shifter 128 and the output signal of the controller 130; The high power mode according to the switching switching signal of the driving amplifier 143 and the controller 130 to compensate for the conversion loss of the output signal of the mixer 142, the first mixer 141 and the second mixer 142. A switch 144 for switching switching in the low power mode, a power amplifier 145 for high power amplifying the output signal of the driving amplifier 143 to a predetermined signal power level according to the switching switching in the high power mode, and driving according to the switching switching in the low power mode. Scheduled output signal of amplifier 143 A signal power level includes a band-pass filter 147 for removing interference signals embedded in the output signal of the drive amplifier 146, and the power amplifier 145 or the drive amplifier 146 to a low power amplifier.

On the other hand, the radio frequency identification system by the wireless communication between the reader 100 and the tag 200 is the measured distance with the tag 200 through the size of the RF signal received from the tag 200 through the reader 100 The RFID ID recognition distance may be determined, and the variable control high power mode or the low power mode may be set according to a result generated by comparing the RFID ID recognition distance with the predetermined reference distance or whether the tag is recognized. In the variable control high power mode, when a tag recognition error occurs in a state in which the reader 100 operates in a low power mode, the variable control high power mode is generated by variably controlling the power amplification factor according to the magnitude of the RF signal fed back and applied. This mode is to send control high output signal.

In addition, the reader 100 transmits the first high output signal in the variable control high power mode, and the second high output signal or the second variable output variable according to the magnitude of the feedback RF signal applied from the tag until tag recognition is performed. The process of generating the Nth high output signal and sending it to the tag is repeated. Of course, the variable control high output signal is obviously limited to the amplification factor that can be output in the high output mode of the reader 100.

Furthermore, the radio frequency identification system by wireless communication between the reader 100 and the tag 200 determines the magnitude of power of the received RF signal by transmitting power to the tag 200 through the reader 100. Set the RF ID recognition distance with the tag 200 according to the power size of the signal, set the high power mode or the low power mode according to the result generated by comparing the RF ID recognition distance with the preset reference distance, and then low power If it is determined that the tag recognition is not made through the feedback RF signal received from the tag 200 in the mode of operation, it may be implemented to switch to the variable control high power mode for variable control of the power amplification step by step. Do.

Hereinafter, the operation of the low power radio frequency identification method according to the present invention with reference to the accompanying drawings in more detail.

FIG. 4 is a flowchart illustrating an operation of the low power radio frequency identification system shown in FIG. 2. As shown in FIG. 4, in the method for implementing a low power RF recognition system, the reader 100 receives an RF signal of a tag 200 that transmits a response signal being stored in response to a question signal of the reader 100. It comes from doing (S100). The reader 100 executes a process of checking a setting state of a power mode for self operation (S102).

In step S102, when the reader 100 is set to the automatic power mode, the power size of the RF signal received from the tag 200 is determined (S104), and the reader is determined according to the result of the power size of the RF signal. In step S106, the RFID recognition distance between the 100 and the tag 200 is set. In step S108, the set RFID recognition distance is compared with a preset reference distance (preferably set to a distance within 1 meter). When the RFID recognition distance is greater than the reference distance, the distance between the reader 100 and the tag 200 is relatively far, so that the reader 100 is switched to the high power mode (S110), and the reader 100 Switching is switched to operate the power amplifier 145 provided in the transmitter 140 (S112). Thereafter, the high output signal, which is the output signal of the power amplifier 145, is filtered and transmitted to the tag 200 (S114).

Furthermore, in step S108, when the RFID recognition distance is less than the reference distance, the reader 100 is switched to the low power mode as the distance between the reader 100 and the tag 200 is relatively close ( S116), the switching switch to the drive amplifier 146 provided in the transmitter 140 of the reader 100 to operate (S118). Thereafter, the low output signal of the drive amplifier 146 is filtered and transmitted to the tag 200 (S120).

Meanwhile, in step S102, when the reader 100 is set to the manual power mode, the reader 100 checks the high power mode or the low power mode manually set by the user (S122). In step S122, when the user sets the reader 100 to the high power mode, the power mode of the reader 100 is switched to the high power mode (S124), and the power amplifier provided in the transmitter 140 of the reader 100 ( 145 is driven (S126). Thereafter, the high output signal of the power amplifier 145 is transmitted to the tag 200 (S128). In addition, when the user sets the reader 100 to the low power mode, the power mode of the reader 100 is switched to the low power mode (S130), and the drive amplifier 146 provided in the transmitter 140 of the reader 100 is turned on. Drive (S132). Thereafter, the low output signal of the drive amplifier 146 is transmitted to the tag 200 (S134).

Furthermore, the low power radio frequency identification system and method by the wireless communication between the reader 100 and the tag 200 is for the RF signal received from the tag 200 when the power mode of the reader 100 is manually set. When the reception rate is weak, the high power signal may be automatically switched to the high power mode to transmit the high output signal output by driving the power amplifier 145 to the tag 200. In addition, since the reception rate for the RF signal received by the reader 100 is weak and automatically switches to the high power mode, the auto power mode automatically operates in real time according to the power size of the RF signal received from the tag 200. It is preferable to be set.

In addition, the reception rate for the RF signal is not only weak, it is preferably implemented to automatically switch to the high power mode even when the tag 200 does not respond to the question signal transmitted by the reader 100.

On the other hand, the radio frequency recognition method by the wireless communication between the reader 100 and the tag 200 of another method is based on the RF ID recognition distance determined by the size of the RF signal or feedback RF signal received by the reader 100 According to the result generated by comparing the set reference distance or whether the tag is recognized, it is classified to operate in the variable control high power mode or the low power mode. ) Can be operated in variable control high power mode to control the power amplification factor of the variable control high output signal for transmission to the tag step by step.

In addition, the radio frequency recognition method by the wireless communication between the reader 100 and the tag 200 according to the size of the received RF signal in the state in which the reader 100 operating in the high power mode or low power mode operates in the low power mode If the tag 200 is not recognized, the tag 200 may be implemented to switch to the variable control high power mode that variably controls the power amplification step by step.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below. I can understand that you can.

Therefore, according to the present invention, since the power mode is actively set according to the radio wave environment received by the RFID reader and the RFID reader, the operating time of the reader is increased and the battery capacity can be used. This has the advantage of producing a small reader.

Claims (33)

In the radio frequency recognition system by wireless communication between the reader and the tag, The reader determines a radio frequency identification (RFID) recognition distance, which is an actual distance from the tag, based on the size of the RF signal received from the tag, and compares the determined RF ID recognition distance with a preset reference distance. Low-power radio frequency identification system, characterized in that operating in a high power mode or a low power mode according to the generated result. The method of claim 1, wherein the leader A receiving unit which receives the RF signal transmitted from the tag in response to a question signal of a reader; A signal processing unit for providing a signal in synchronization with a coherent frequency channel to a communication frequency of an RF signal that is an output signal of the receiver and an RF signal that is an output signal of the receiver to a controller; The RF ID recognition distance with the tag is determined based on the magnitude of the RF signal, which is an output signal of the receiver, and the high power mode or the low power mode is determined according to a result generated by comparing the determined ID recognition distance with a preset reference distance. A controller configured to generate a frequency selection signal for selecting a frequency channel corresponding to the set mode; And And a transmitter for amplifying or driving an output signal applied from the controller through the frequency channel switched by the signal processor based on the frequency selection signal and transmitting the power amplification or drive amplification to the tag. Low power radio frequency identification system. The method of claim 2, wherein the receiving unit A band pass filter for passing the RF signal through a predetermined frequency band; A low noise amplifier for removing noise components of the output signal of the band pass filter; And And a power gain control amplifier for maintaining the output signal power level of the low noise amplifier. The method of claim 2, wherein the signal processing unit At least one frequency generator for generating respective frequencies in a frequency band for RF wireless communication; A phase locked loop circuit for generating a predetermined frequency based on a frequency output from the at least one frequency generator; Connected to an output terminal of the phase locked loop circuit and switched on / off according to a frequency selection signal of the controller to transmit the phase locked loop circuit through a frequency channel coherent to a communication frequency of an RF signal which is an output signal of the receiver. At least one switch for passing an output signal; A first mixer for mixing the output signal of the receiver and the output signal of the switch switched to the on state and transmitting the mixed signal to the controller; And And a second mixer for mixing a phase shifted signal of an output signal of the switch switched to the on state and an output signal of the receiver and transmitting the mixed signal to the controller. The method of claim 4, wherein the control unit The RF ID, which is an output signal of the receiver applied through the first mixer, determines the RF ID recognition distance, and when the determined RFID ID is greater than or equal to a preset reference distance, operates the reader in a high power mode. Low power radio frequency identification system, characterized in that the setting. The method of claim 5, wherein the control unit Determining a frequency channel corresponding to the high power mode, generating a frequency selection signal for the determination result, and transmitting the generated frequency selection signal to the signal processor, and receiving the frequency channel signal formed by the signal processor and transmitting the frequency channel signal as an output signal to the transmitter; And transmitting the switching switching signal for the high power mode to the transmitter to amplify the output signal due to the frequency channel signal. The method of claim 4, wherein the control unit Determining the RF ID recognition distance by determining the magnitude of the RF signal which is an output signal of the receiver applied through the first mixer, and operating the reader in a low power mode when the determined RF ID recognition distance is less than a preset reference distance. Low power radio frequency identification system, characterized in that the setting. The method of claim 7, wherein the control unit Determining a frequency channel corresponding to the low power mode, generating a frequency selection signal for the determination result, and transmitting the generated frequency selection signal to the signal processor, and receiving the frequency channel signal formed by the signal processor and transmitting the frequency channel signal as an output signal to the transmitter; And transmitting the switching switching signal for the low power mode to the transmitter to drive amplify the output signal due to the frequency channel signal. The method of claim 4, wherein the second mixing unit And a 90 degree phase shifted signal output signal of the switch switched to the on state and an output signal of the receiving unit are mixed and transmitted to the control unit. The method of claim 2, wherein the transmitting unit A first mixer configured to collect and output an output signal of the switch switched to the ON state from the signal processor and an output signal of the controller; A second mixer for collecting and outputting a 90 degree phase shifted signal of the switch switched to the on state and an output signal of the controller; A drive amplifier for compensating for the conversion loss of the output signals of the first mixer and the second mixer; A switch for switching switching of a high power mode or a low power mode according to a switching switching signal of the controller; A power amplifier for high power amplifying the output signal of the driving amplifier to a predetermined signal power level according to a switching switching of a high power mode; A drive amplifier for low power amplifying the output signal of the drive amplifier to a predetermined signal power level according to a switching switching of a low power mode; And And a band pass filter for canceling an interference signal inherent in an output signal of the power amplifier or the drive amplifier. In the radio frequency recognition system by wireless communication between the reader and the tag, The reader determines a RFID ID recognition distance, which is a measured distance from the tag, based on the size of the RF signal received from the tag, and compares the determined RFID ID recognition distance with a preset reference distance, or generates a tag recognition. Operating in a variable control high power mode or low power mode depending on whether The variable control high power mode, When the tag recognition error occurs in the low power mode of the reader, a low power radio frequency identification system, characterized in that the mode for transmitting a high output signal generated by varying the power amplification rate in accordance with the size of the RF signal. The method of claim 11, wherein the leader The first high output signal is transmitted in the variable control high power mode, and the second high output signal or the Nth high output signal is variably controlled according to the magnitude of the feedback RF signal applied from the tag until tag recognition is performed. Low power radio frequency identification system characterized in that the transmission. The method of claim 12, wherein the leader A receiver configured to receive the RF signal or the feedback RF signal transmitted in response to a question signal of a reader from the tag; A signal processing unit for providing a signal in which a coherent frequency channel is synchronized with a communication frequency of an RF signal that is an output signal of the receiver and an RF signal that is an output signal of the receiver to a controller; The RF ID recognition distance with the tag is determined based on the magnitude of the RF signal, which is an output signal of the receiver, and the variable ID high power mode or the low power mode is generated according to the result generated by comparing the determined ID recognition distance with a preset reference value. A controller configured to generate a frequency selection signal for selecting a frequency channel corresponding to the set mode; And Drive amplification of an output signal applied from the controller through the frequency channel switched by the signal processor based on the frequency selection signal according to the low power switching switching signal of the controller, or power step by step according to the variable control switching switching signal of the controller. And a transmitter for amplifying and transmitting the tag to the tag. The method of claim 13, wherein the control unit Variable control high power mode for controlling power amplification rate step by step when the RF ID recognition distance determined by the magnitude of the RF signal that is the output signal of the receiver is greater than or equal to a preset reference value or when tag recognition is not performed. Low power radio frequency identification system, characterized in that for setting the reader operation. The method of claim 14, wherein the control unit Determine a frequency channel corresponding to the variable control high power mode, generate a frequency selection signal based on the determination result, and transmit the generated frequency selection signal to the signal processor, and then receive the frequency channel signal formed by the signal processor and transmit the frequency channel signal as an output signal to the transmitter. And transmitting the variable control switching switching signal corresponding to the power amplification factor to the transmitter to amplify the output signal due to the frequency channel signal in a predetermined step. In the reader for wireless communication by tag and Radio Frequency Identification (RFID), The reader determines the power size of the received RF signal by transmitting power to the tag, and sets an RFID ID distance with the tag according to the power size of the RF signal, and the RFID ID distance and a preset reference distance. Operate in the high power mode or the low power mode according to the result generated by comparing the two; When the tag recognition is not made through the feedback RF signal received in the state of operating in the low power mode, the reader characterized in that switching to a variable control high power mode for variable control of the power amplification step by step. The method of claim 16, wherein the leader is A receiver configured to receive the RF signal or the feedback RF signal transmitted in response to an interrogation signal of a reader from the tag energized through the power transmission; A signal processing unit for providing a signal in synchronization with a coherent frequency channel to a communication frequency of an RF signal that is an output signal of the receiver and an RF signal that is an output signal of the receiver to a controller; The RF ID recognition distance with the tag is determined based on the power size of the RF signal, which is an output signal of the receiver, and the high power mode or the low power mode is generated according to the result generated by comparing the determined ID identification distance with a preset reference distance. A controller configured to switch to a variable control high power mode and generate a frequency selection signal for selecting a frequency channel corresponding to the set mode when tag recognition is not performed in the low power mode; And Based on the frequency selection signal, an output signal applied from the controller through a frequency channel switched by the signal processor is amplified or driven according to the switching switching signal of the controller, or stepwise according to the variable control switching switching signal of the controller. And a transmitter for amplifying the power and transmitting the power to the tag. Radio frequency recognition method by wireless communication between reader and tag. (A) the reader receiving an RF signal from the tag; (B) checking whether the power mode setting of the reader is manual or automatic; (C) when the power mode of the reader is automatically set, determining an RFID distance with the tag by determining the magnitude of the RF signal, and comparing the RFID recognition distance with the preset reference distance. ; (D) operating in a high power mode or a low power mode according to a result generated by comparing the set RFID ID with a preset reference distance; And (E) transmitting the high power signal or the low power signal generated by the real-time displacement to the tag through the reader operating in the high power mode or the low power mode. 19. The method of claim 18, wherein step (b) And setting a high power mode or a low power mode by a reader user when the power mode setting of the reader is manual. 20. The method of claim 19, wherein step (b) And when the reader is set to operate in a high power mode, transmitting a high output signal generated by power amplifying the RF signal received from the tag to the tag. 20. The method of claim 19, wherein step (b) And when the reader is set to operate in a low power mode, transmitting a low output signal generated by drive amplifying the RF signal received from the tag to the tag. 19. The method of claim 18, wherein (d) When the RFID recognition distance is more than a predetermined reference distance, the low power radio frequency identification method, characterized in that for setting the reader operation in a high power mode. The method of claim 22, wherein the step (d) If the RFID recognition distance is less than a predetermined reference distance, low power radio frequency recognition method characterized in that the reader operation set to the low power mode. The method of claim 18, wherein the step (e) (E-1) determining a frequency channel corresponding to the high power mode or the low power mode; (E-2) generating a frequency selection signal for setting the determined frequency channel; (E-3) transmitting the frequency channel signal processed based on the frequency selection signal to a transmitter of the reader; (E-4) transmitting a switching switching signal for high output amplification or low output amplification of the frequency channel signal corresponding to a predetermined power mode to the transmitter; And (E-5) low power radio frequency identification method comprising the step of transmitting the high output signal or low output signal of the transmitter to the tag. In the radio frequency recognition method by the wireless communication between the reader and the tag, (A) receiving, by the reader, an RF signal from the tag operating by power transmission; (B) checking whether the power mode setting of the reader is manual or automatic; (C) automatically switching to a high power mode if a reception rate for the RF signal does not reach a predetermined level when the power mode of the reader is manually set; And (D) transmitting a high power signal generated by the reader operating in the high power mode to the tag. The method of claim 25, wherein the method is If the reception rate for the RF signal received by the reader is weaker than the predetermined reception rate, after the automatic switching to the high power mode, the step of setting to the automatic power mode automatically operates in real time displacement according to the power size of the RF signal Low power radio frequency identification method, characterized in that. The method of claim 25, wherein the (c) step A method for low power radio frequency recognition, wherein the RF signal is automatically switched to a high power mode not only when the reception rate of the RF signal is weaker than a preset reception rate but also when the tag does not respond to the question signal transmitted by the reader. Radio frequency recognition method by wireless communication between reader and tag. (A) the reader receiving an RF signal or a feedback RF signal from the tag; (B) checking whether the power mode setting of the reader is manual or automatic; (C) When the power mode of the reader is automatically set, the RF ID recognition distance with the tag is determined based on the magnitude of the RF signal or the feedback RF signal, and the RF ID recognition distance and the preset reference distance are set. Comparing the; (D) determining whether to recognize the tag; (E) operating in a variable control high power mode or a low power mode according to a result generated by comparing the set RFID recognition distance with a predetermined reference distance or whether a tag is recognized; And (G) transmitting a variable control high output signal or a low output signal generated by a real time displacement to the tag through a reader operating in the variable control high power mode or low power mode. The method of claim 28, wherein step (e) And when the RFID recognition distance is greater than or equal to a predetermined reference distance or when tag recognition is not performed, a reader operation is set in a variable control high power mode. The method of claim 29, wherein step (e) And a step of increasing the power amplification step by step until tag recognition is made due to the feedback RF signal applied from the tag in response to the variable control high output signal. The method of claim 28, wherein step (e) When the RFID recognition distance is less than the predetermined reference distance or the tag recognition is made, the low power radio frequency recognition method, characterized in that for setting the reader operation in a low power mode. Radio frequency recognition method by wireless communication between reader and tag. (A) the reader receiving an RF signal from the tag; (B) checking whether the power mode setting of the reader is manual or automatic; (C) when the power mode of the reader is automatically set, determining an RFID recognition distance with the tag through the size of the RF signal, and comparing the set RFID recognition distance with a preset reference distance; (D) operating in a high power mode or a low power mode according to a result generated by comparing the set RFID ID with a preset reference distance; (E) switching to a variable control high power mode to variably control power amplification rate step by step when tag recognition is not performed in the low power mode operation state; And (G) transmitting a variable control high power signal amplified in correspondence with the power amplification rate to the tag through a reader operating in the variable control high power mode. 33. The method of claim 32, wherein Low power characterized in that the step of increasing the power amplification step by step to the maximum amplification of the variable control high power mode until the tag recognition is achieved through a feedback RF signal applied from the tag corresponding to the variable control high output signal Radio Frequency Recognition Method.

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