KR100807109B1 - Reader of rfid system and controlling methdo therefore - Google Patents

Abstract

In a multi-environment including a plurality of readers and a plurality of tags, a reader and control of a radio frequency recognition system for detecting a frequency channel during communication between adjacent readers and tags and selecting a communication frequency channel based on the detected communication channel A method is disclosed. The present invention is a reader of a radio frequency recognition system in a multi-environment that transmits and receives RF signals between a plurality of readers and tags, and receives an RF signal supplied from an adjacent reader to remove noise components included in the received RF signal. A signal receiving unit for removing and amplifying and converting the amplified RF signal into digital data, a communication channel detecting unit detecting a frequency channel having a use frequency in communication between the adjacent reader and a tag through an output signal of the signal receiving unit, and And a signal transmitter that hops to a frequency channel having a remaining use frequency except for a frequency channel having a currently used communication frequency detected by the communication channel detector and then transmits an RF signal modulated to the hopped frequency channel as a tag.

Radio Frequency Identification System, Adaptive Frequency Hopping, SAW Filter

Description

READER OF RFID SYSTEM AND CONTROLLING METHDO THEREFORE}

1 is a view showing the configuration of a general radio frequency recognition system.

FIG. 2 is a diagram illustrating an operating state of the radio frequency recognition system shown in FIG. 1.

3 is a view showing the configuration of a reader of a radio frequency identification system according to the present invention.

4 is a diagram illustrating a transmission format of an RF signal illustrated in FIG. 3.

5 is a flowchart illustrating a reader control process of a radio frequency identification system according to the present invention.

<Description of the symbols for the main parts of the drawings>

100: reader 10: signal receiving unit

11: low noise amplifier 13: unwanted wave filter

15: analog / digital converter 20: communication channel detector

21 microprocessor 23 pseudo noise information detector

25 memory unit 27 intermediate frequency detection unit

30 signal transmission unit 31 phase locked loop unit

33: signal processing unit 300: tag

The present invention relates to a reader and a control method of the radio frequency recognition system. More specifically, the reader and the tag in an adaptive frequency hopping method using a single wave filter in a multi-environment having a plurality of readers and a plurality of tags. An apparatus and method are provided for enabling communication between them.

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 therein, the tag 5 consists 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 therein, the plurality of readers 1 transmit RF signals 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 receives the operating power required to operate the IC chip from the high frequency carrier signal of the reader 1. 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 the tag 5 as well as transmitting information between the reader 1 and the tag 5.

In a multi-environment of a radio frequency identification system that communicates between a plurality of readers and tags in a single cell, a plurality of carrier signals are generated by a frequency synthesizer of a phase locked loop to send predetermined information (question signals). Select the frequency used by FHSS or AFA-LBT.

In the LBT method, when communication is performed between a first reader R1 and a tag among a plurality of readers, other readers R2-Rn except for the first reader R1 monitor the channel state and then the first reader R1. Communication is completed and the channel is boiled, and the other reader (R2) is connected according to the sequence of the communication protocol.

In addition, the FHSS scheme for preventing the interference between the available channel and the channel is to communicate between the reader 1 and the tag while changing the use frequency at predetermined time intervals.

Since frequency hopping is performed randomly in the RFID system accessed by the frequency hopping method, communication is performed after waiting for communication to be completed when hopping at the channel frequency being communicated. Therefore, in order to prevent such communication delay, the recent RFID system accesses by adaptive frequency hopping.

The RFID system accessed by the adaptive frequency hopping method searches for a communication frequency channel before communication between the reader and the tag, hops to a communication frequency channel according to a search result, and then tags an RF signal through the hopping frequency channel. To send.

In this case, the reader uses a plurality of unnecessary wave filters for extracting RF signals of the communicable frequency channel to search for the communicable frequency channel. For example, if there are 10 frequency channels that can communicate, 10 wave filters (SAW filters) are needed to extract RF signals of each frequency channel. However, since the characteristics of the filter are variable and expensive according to the external temperature, the reliability of the product is lowered, and the use of a plurality of filter filters causes problems in manufacturing cost and manufacturing process.

The present invention has been proposed to solve the above problems, and an object of the present invention is to detect and detect a frequency channel in communication using pseudo noise information of a preamble code included in RF signals of all frequency channels that can be communicated. By using one clutter filter to extract RF signals of all communicable frequency channels for hopping to the remaining frequency channels except the frequency channels, it improves product reliability, simplifies the manufacturing process and improves manufacturing costs. An object of the present invention is to provide a reader and a control method of a radio frequency recognition system.

Technical means according to the first aspect of the present invention for achieving this object,

In a reader of a radio frequency recognition system of a multi-environment that transmits and receives RF signals between a plurality of readers and tags,

A signal receiver which receives an RF signal supplied from an adjacent reader, removes a noise component included in the received RF signal, amplifies it, and converts the amplified RF signal into digital data;

A communication channel detector for detecting a frequency channel having a current frequency currently being communicated between the adjacent reader and a tag through an output signal of the signal receiver;

And a signal transmitter for hopping to a frequency channel having a remaining use frequency except for a frequency channel having a currently used communication frequency detected by the communication channel detector, and then transmitting an RF signal modulated to the hopping frequency channel to a tag.

Here, the signal receiving unit

A low noise amplifier which removes noise components included in RF signals communicating between adjacent readers and tags and amplifies them to a predetermined level;

An unwanted wave filter for detecting RF signals in all frequency bands that can be communicated among the output signals of the low noise amplifier;

And an analog / digital converter for converting the output signal of the unwanted wave filter into a digital signal, wherein the unwanted wave filter is provided as one for extracting RF signals of all communicable frequency bands.

In addition, the communication channel detector,

A microprocessor that stores pseudo noise information for all communication channels;

Correlation is greater than or equal to a reference value by measuring a correlation between an output signal of the signal receiver based on pseudo noise information inserted into a preamble code of an output signal of the signal receiver and pseudo noise information of all communicable channels of the microprocessor. A pseudo noise information detector for outputting an output signal of the signal receiver;

A memory unit for storing intermediate frequency table values for all communication channels;

Detects an intermediate frequency of the pseudo noise information detector based on an output signal of the pseudo noise information detector and an output signal of the memory unit, and detects an intermediate frequency for hopping of the remaining frequency channels except for the detected intermediate frequency. And an intermediate frequency output unit for supplying an intermediate frequency excluding a frequency to the signal transmitter.

On the other hand, the technical means according to the second aspect of the present invention for achieving the above object,

Receives an RF signal in communication between a reader and a tag through a signal receiver, detects a frequency channel currently being used by the communication channel detector, hops to a frequency channel other than the detected frequency channel, and hops through a signal transmitter. In a reader control method of a radio frequency recognition system for supplying a predetermined question signal to a tag in a channel,

a) receiving an RF signal communicating between an adjacent reader and a tag through the signal receiving unit, extracting RF signals of all communicable frequency bands, and converting the extracted RF signal into a digital form;

b) outputting a highly correlated RF signal by comparing the pseudo noise information of the preamble code included in the RF signal converted into the digital form through the communication channel detector with a plurality of pseudo noise information included in the microprocessor;

c) comparing the intermediate frequency of the RF signal output through the step b) with the intermediate frequency stored in the memory unit to detect the intermediate frequency of the RF signal, and outputting the remaining intermediate frequencies except the detected intermediate frequency; And

d) mixing the output intermediate frequency with a predetermined question signal (RF signal) through the signal transmitter, and modulating and supplying the intermediate frequency to a tag.

According to the present invention, one frequency filter detects a frequency channel in communication using pseudo noise information included in a preamble code among data communicating between an adjacent reader and a tag by using one unwanted wave filter, and the remaining frequency channels except for the detected frequency channel. By communicating between the reader and the tag through the product, the reliability of the product can be improved, and the manufacturing process and manufacturing cost can be improved.

Hereinafter, the most preferred embodiments of the present invention will be described with reference to the accompanying drawings in order to be described in detail to those skilled in the art can easily practice the present invention.

3 is a view showing the configuration of the reader of the radio frequency recognition system according to the present invention, Figure 4 is a view showing the configuration of the transmission format of the RF signal shown in FIG. The reader 100 of the radio frequency recognition system according to the present invention includes a signal receiver 10 for receiving an RF signal f1 received through the antenna and a communication channel detector connected to an output side of the signal receiver 10. And a signal transmitter 30 connected to the output side of the communication channel detector 20.

Here, the signal receiving unit 10 is provided to receive the RF signal supplied from the reader (R1) in a cell to remove the noise component included in the RF signal and then amplify and convert the amplified signal into digital data. That is, the signal receiver 10 includes a low noise amplifier 11 for removing a noise component included in the RF signal and amplifying the signal to a predetermined level, and an RF in a communication frequency band including an output signal of the low noise amplifier 11. The wave filter 13 which detects a signal, and the analog-to-digital converter 15 which converts the output signal of the wave filter 13 into a digital signal are included. Here, the unwanted wave filter 13 is provided to extract all RF signals of the frequency band that can communicate.

In addition, the communication channel detector 20 may include a microprocessor 21 in which pseudo noise information (P / N (1) -P / N (n)) for all communicable frequency channels is stored, and the signal receiver ( Pseudo-noise information (P / N (1)) of the preamble code included in the output signal of the analog-to-digital converter (15) of 10) and pseudo-noise information (P / N (1)-) stored in the microprocessor 21. Pseudo-noise information detector 23 for measuring the correlation of P / N (n) and outputting the output signal of the signal receiver 10 having high correlation, and intermediate frequency table values for all the channels that can communicate Detects and detects an intermediate frequency with respect to the output signal of the pseudo noise information detection unit 23 based on the memory unit 25, the output signal of the pseudo noise information detection unit 23 and the intermediate frequency of the memory unit 25. The probe for hopping of the remaining frequency channels except the And an intermediate frequency output unit 27 for supplying an intermediate frequency except the emitted frequency to the signal transmitter 30.

The signal transmitter 30 outputs a phase locked loop 31 and an output signal of the phase locked loop 31 that generate a use frequency that is phase-locked based on the intermediate frequency supplied from the intermediate frequency output 27. And a signal processor 33 for mixing the used frequency and then modulating the RF frequency into a tag 300. Here, since the configuration of the phase locked loop 31 and the signal processor 33 is a known technique already known to those skilled in the art, detailed description thereof will be omitted.

The reader 100 of the radio frequency recognition system according to the present invention having the above-described configuration, first, in the multi-environment in which a plurality of readers R1 and tags 300 exist in one cell, the reader R1 and the tag ( An RF signal communicating between 300 is received through the antenna and the signal receiving unit 10.

That is, the RF signal is supplied to the low noise amplifier 11 of the signal receiver 10, and the low noise amplifier 11 amplifies to a predetermined level after removing the noise included in the received RF signal.

The output signal of the low noise amplifier 11 is supplied to the wave filter 13, and the wave filter 13 includes a frequency band including all frequency channels that can communicate among the output signals of the low noise amplifier 11. Extract the RF signal. For example, if the frequency band that can be communicated is 810 MHz to 814 MHz, and there are 10 channels in this frequency band, the RF signal of the frequency band including all the frequency channels that can communicate according to the characteristic of the wave filter 13 is output. do.

The output signal of the wave filter 13 is supplied to the analog-to-digital converter 15, and the analog-to-digital converter 15 converts the received RF signal into a digital signal and then converts the unwanted wave into a digital signal. The output signal of the filter 13 is supplied to the pseudo noise information detector 23 of the communication channel detector 20.

At this time, the output signal of the analog-to-digital converter 15 is a preamble detect code (preamble detect) for transmitting a continuous wave (CW) of about 400 kHz, a preamble code (preamble) indicating the start of the picket A delimiter code for determining the data ratio of the response signal, a command code indicating the type of command, a parameter code, a data code, and a CRC (Cycle) for detecting a data transmission error Redundancy Check) code.

Here, the preamble code includes pseudo noise information (P / N 1) of the RF signal.

The pseudo noise information detecting unit 23 is capable of communicating all of the pseudo noise information P / N 1 inserted into the preamble code of the output signal of the received analog / digital converting unit 15 and the microprocessor 21. The correlation between the pseudo noise information (P / N (1) -P / N (n)) of the channel is measured, and the RF signal of the frequency channel with high correlation is output.

The output signal of the pseudo noise information detection unit 23 is supplied to the intermediate frequency output unit 27, and the intermediate frequency output unit 27 detects the intermediate frequency of the output signal of the pseudo noise information detection unit 23. Then, the detected intermediate frequency is compared with a plurality of intermediate frequencies stored in the memory unit 25, and then the intermediate frequencies of the remaining communication frequency channels except for the corresponding intermediate frequency are output.

The intermediate frequency of the intermediate frequency output unit 27 is supplied to the phase locked loop unit 31 of the signal transmitter 30, and the phase locked loop unit 31 is supplied to the intermediate frequency output unit 27. A use frequency f2 is phase-locked based on the frequency, and the generated use frequency is supplied to the signal processor 33.

The signal processor 33 mixes and modulates the frequency of use of the phase-locked loop and the question signal (RF signal) to be transmitted to the tag 300 and modulates the change of the electrical signal on the lead to electromagnetic waves in the air. The tag located within the region of the electromagnetic wave among the plurality of tags 300 receives this RF signal.

Next, the reader control process of the radio frequency identification system according to the present invention will be described through an embodiment of the radio frequency recognition system to which the reader configured as described above is applied.

FIG. 5 is a flowchart illustrating a reader control process of a radio frequency identification system according to the present invention, in which the same parts as in FIG. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.

First, the signal receiver 10 receives an RF signal communicating between an adjacent reader R1 and a tag 300 (step 501), extracts RF signals of all frequency bands that can be communicated (step 503), and extracts the extracted RF signal. The RF signal is converted into digital form (step 505).

The RF signal converted into a digital form through the step 505 is supplied to a pseudo noise information detector 23, and the pseudo noise information detector 23 is a pseudo noise included in a preamble code of the received RF signal. The information is compared with a plurality of pseudo noise information included in the microprocessor 21 (step 506) to output a highly correlated RF signal (step 507).

Subsequently, the RF signal output through the step 507 is supplied to the intermediate frequency output unit 27, and the intermediate frequency output unit 27 is an intermediate frequency of the received RF signal and the intermediate frequency stored in the memory unit 25. The frequencies are compared to detect the intermediate frequency of the RF signal (step 509), and the remaining intermediate frequencies except the detected intermediate frequency are output (step 511).

The intermediate frequency output in step 511 is supplied to the signal transmitter 30, and the signal transmitter 30 uses a frequency having an intermediate frequency output in step 511 and a predetermined question signal (RF signal). ) Are mixed and modulated and supplied to the tag 300 (step 513).

As described above, a reader and a control method thereof according to the present invention use pseudo noise information included in a preamble code among data communicating between an adjacent reader and a tag using a single wave filter. By detecting the frequency channel in communication and communicating between the reader and the tag through the remaining frequency channels except the detected frequency channel, the reliability of the product can be improved, and the manufacturing process and manufacturing cost can be improved.

What has been described above is only one embodiment for implementing a fuel saving method of an automobile according to the present invention, the present invention is not limited to the above embodiment, as claimed in the following claims of the present invention Without departing from the gist of the present invention, one of ordinary skill in the art will have the technical spirit of the present invention to the extent that various modifications can be made.

Claims (5)

In a reader of a radio frequency recognition system of a multi-environment that transmits and receives RF signals between a plurality of readers and tags, A signal receiver which receives an RF signal from an adjacent reader, removes and amplifies noise components included in the RF signal, and converts the amplified RF signal into digital data; A communication channel detector for detecting a frequency channel having a current frequency currently being communicated between the adjacent reader and a tag through an output signal of the signal receiver; And a signal transmitter for performing a hopping to a frequency channel having a remaining use frequency except for a frequency channel having a currently used communication frequency detected by the communication channel detector and then transmitting an RF signal modulated to the hopping frequency channel as a tag. The signal receiver A low noise amplifier which removes noise components included in RF signals communicating between adjacent readers and tags and amplifies them to a predetermined level; An unwanted wave filter for detecting RF signals in all frequency bands that can be communicated among the output signals of the low noise amplifier; And an analog / digital converter for converting the output signal of the unwanted wave filter into a digital signal. delete The reader of claim 1, wherein the unwanted filter is one for extracting RF signals of all frequency bands that can be communicated with. The communication channel detection unit according to claim 1 or 3, A microprocessor that stores pseudo noise information for all communication channels; Correlation is greater than or equal to a reference value by measuring a correlation between an output signal of the signal receiver based on pseudo noise information inserted into a preamble code of an output signal of the signal receiver and pseudo noise information of all communicable channels of the microprocessor. A pseudo noise information detector for outputting an output signal of the signal receiver; A memory unit for storing intermediate frequency table values for all communication channels; Detects an intermediate frequency of the pseudo noise information detector based on an output signal of the pseudo noise information detector and an output signal of the memory unit, and detects an intermediate frequency for hopping of the remaining frequency channels except for the detected intermediate frequency. And an intermediate frequency output unit for supplying an intermediate frequency excluding a frequency to the signal transmitter. Receives the RF signal in communication between the adjacent reader and the tag through the signal receiver, detects the current frequency channel from the communication channel detector, hops to the remaining frequency channels except the detected frequency channel, and hops through the signal transmitter. In a reader control method of a radio frequency recognition system for supplying a predetermined question signal to a tag in a frequency channel, a) receiving an RF signal communicating between an adjacent reader and a tag through the signal receiving unit, extracting RF signals of all communicable frequency bands, and converting the extracted RF signal into a digital form; b) outputting a highly correlated RF signal by comparing the pseudo noise information of the preamble code included in the RF signal converted into the digital form through the communication channel detector with a plurality of pseudo noise information included in the microprocessor; c) comparing the intermediate frequency of the RF signal output through the step b) with the intermediate frequency stored in the memory unit to detect the intermediate frequency of the RF signal, and outputting the remaining intermediate frequencies except the detected intermediate frequency; And and d) mixing the output intermediate frequency with a predetermined question signal (RF signal) through the signal transmitter and modulating and supplying the intermediate frequency to a tag.

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