KR20080058524A - Network measurement system of radio frequency identification reader - Google Patents

Abstract

An RFID(Radio Fequency Identification) reader network measurement system is provided to measure various environment factors of RFID communication quickly, and manage measurement data effectively by interworking with an external NMS(Network Management System). A phase-locked circuit unit(140) generates a plurality of oscillation frequency signals divided at certain intervals within an RFID frequency range. A mixer unit(145) sequentially mixes signals received via an antenna(105) with the oscillation frequency signals to convert them into a plurality of IF(Intermediate Frequency) signals. A sensing unit(160) generates discriminated digital signal according to power levels of the IF signals. A controller(165) interprets the digital signals to generate analysis numeric value information of RFID communication environment. The first coupling unit(115) couples the reception signals. The second coupling unit(120) couples signals fed back from the antenna. The first switch unit(125) switches the coupled reception signals to the mixer unit. The second switch unit(130) switches the coupled feedback signals to the mixer unit.

Description

RFID reader network measurement system {Network measurement system of Radio Frequency IDentification reader}

1 is a block diagram schematically showing the components of an RFID reader network measurement system according to an embodiment of the present invention;

FIG. 2 is a diagram illustrating a form implemented as a circuit from an antenna to a mixer of an RFID reader network measuring system according to an exemplary embodiment of the present invention.

3 is a graph measuring a signal processed by a sensor of the RFID reader network measurement system according to an embodiment of the present invention.

4 is a diagram illustrating a screen processed by the GUI processing unit of the RFID reader network measurement system according to an embodiment of the present invention.

5 is a diagram illustrating an external terminal interoperable with an RFID reader network measurement system according to an embodiment of the present invention.

6 is a diagram illustrating a user interface screen provided by an external terminal interoperable with an RFID reader network measurement system according to an exemplary embodiment of the present invention.

7 is a block diagram schematically illustrating the components of a measurement RF transmission system interworking with an RFID reader network measurement system according to an embodiment of the present invention.

<Explanation of symbols for main parts of drawing>

100: RFID reader network measurement system 105: antenna

110: LNA 115: first coupling part

120: second coupling portion 125: first switch portion

130: second switch unit 135: third switch unit

140: phase synchronization circuit section 145: mixer section

160: detection unit 165: control unit

170: GUI processing unit 175: connection unit

The present invention relates to a system for measuring a propagation environment between readers when a plurality of readers constitute a network.

Currently, ubiquitous network technology has attracted the attention of many people, ubiquitous network technology means a technology that allows to naturally connect to various networks regardless of time and place.

An example of such a ubiquitous network technology is RFID technology. In general, an RFID system includes a tag attached to an item and embedded with details, a reader that reads tag information by using RF communication, and the tag is located in the reader. As the information is transmitted through RF communication through RF communication, it provides a foundation for efficient logistics / distribution management such as product distribution, assembly, price change, and sales.

Since the tag is moved as a communication target, the reader is in an unstable reception environment due to various factors. First, when implemented using ASK (Amplitude Shift Keying) modulation through envelope detection, the recognition rate is lowered. Second, the energy supply structure to the tag (Tag) can be variously changed according to the type of modulation method, third, the phase shift occurs or the reception angle is changed because the tag is moved at high speed, fourth, For example, the same frequency band may be used for transmission and reception, and signal distortion such as phase inversion, recognition distance, and error rate may be differentially generated according to the separation and synthesis of I / Q signals during modulation.

Usually, when readers are installed in buildings or warehouses, dozens or hundreds of readers are installed to form a network, and in this case, the reception environment becomes worse due to the influence of interference signals.

Therefore, in order to configure a network by installing a plurality of readers, it is necessary to measure the radio wave environment of the reader before installation and to grasp the transmission and reception state, and even the deployed leader network needs to periodically manage the radio wave environment.

Conventionally, general measurement equipment that can be commonly used in high-frequency communication systems is used, but because it is not a device for a specific communication system such as an RFID system, there is a limit on items that are cumbersome to use and can be measured.

Therefore, since accurate radio wave measurement and analysis were impossible, it was difficult to efficiently deploy and operate the RFID system.

The present invention provides an RFID reader network measurement system that can easily measure a variety of items in consideration of band characteristics allocated to RFID communication, interband characteristics according to channel division, RFID modulation and demodulation characteristics, and characteristics in which interference signals are easily generated. to provide.

The present invention provides an RFID reader network measurement system capable of quickly measuring various environmental factors of RFID communication and efficiently managing measurement data in connection with an external network management system (NMS).

The RFID reader network measuring system according to the present invention comprises: a phase synchronization circuit unit for generating a plurality of oscillation frequency signals divided at predetermined intervals within an RFID frequency range; A mixer unit which sequentially synthesizes the signal received through the antenna with the oscillation frequency signal and converts the signal into a plurality of intermediate frequency signals; A detector configured to generate a digital signal differentiated according to the power level of the intermediate frequency signal; And a controller configured to interpret the digital signal to generate an analysis value of an RFID communication environment.

Hereinafter, an RFID reader network measurement system according to the present invention will be described in detail with reference to the accompanying drawings. The RFID reader that is measured by the network measurement system is a reader using a signal of a UHF band.

1 is a block diagram schematically illustrating the components of an RFID reader network measurement system 100 according to an embodiment of the present invention, and FIG. 2 is an antenna of an RFID reader network measurement system 100 according to an embodiment of the present invention. FIG. Is a diagram illustrating a form implemented as a circuit from the 105 to the mixer unit 145.

Referring to FIG. 1, the RFID reader network measurement system 100 according to the embodiment of the present invention includes an antenna 105, a low noise amplifier (LNA) 110, a first coupling unit 115, and a second coupling unit 120. ), The first switch unit 125, the second switch unit 130, the third switch unit 135, the phase synchronization circuit unit 140, the mixer unit 145, the filter 150, the first PA 155, The detector 160, the controller 165, the GUI (Graphic User Interface) processor 170, and the connection unit 175 are included.

The antenna 105 receives a signal in the 800 MHz to 1 GHz band, and the received signal is a dedicated radiating device for supplying a signal for measuring a reader, a tag, or a radio wave, which constitutes an RFID network (see FIG. , Which is described as "measurement RF transmission system 50".

The LNA 110 amplifies the power of the signal lowered in the process of being received through the antenna 105, in which the noise component is suppressed and amplified as much as possible.

Hereinafter, the structural part from the antenna 105 end to the mixer part 145 is demonstrated with reference to FIG. 1 and FIG.

Referring to FIG. 2, the ends of the lines connected to the antenna 105 and the LNA 110 are disconnected, and the signal received through the antenna 105 or the feedback reflected from the antenna 105 and returned to the line again. There may be a signal.

The first coupling unit 115 couples the signal transmitted from the LNA 110 to the end of the line, and the second coupling unit 120 couples the signal transmitted from the end of the line to the LNA 110. The first coupling unit 115 couples the received signal and the second coupling unit 120 couples the feedback signal.

The first coupling unit 115 and the second coupling unit 120 may be implemented using various coupling circuits. However, in the exemplary embodiment of the present invention, the first coupling unit 115 and the second coupling unit 120 may be implemented as branch line couplers having excellent signal separation / transmission characteristics. .

In addition, in the exemplary embodiment of the present invention, the first switch unit 125, the second switch unit 130, and the third switch unit 135 may be provided as a semiconductor switching element such as a single pole double throw (SPDT). This is because the control by the controller 165 is easy.

That is, the controller 165 may transmit a switching control signal to the switch units 125, 130, and 135 to select a type of a signal to be interpreted by itself-a received signal or a feedback signal.

The first switch unit 125 switches the received signal coupled from the first coupling unit 115 to two output terminals. One of the two output terminals is connected to the third switch unit 135, and the other is It is connected to the ground terminal.

The second switch unit 130 switches the feedback signal coupled from the second coupling unit 120 to two output terminals. One of the two output terminals is connected to the third switch unit 135, and the other is It is connected to the ground terminal.

When the first switch unit 125 and the second switch unit 130 connect the signal path to the ground terminal side, the signal is isolated to the ground terminal, and thus the measurement function of the signal may be regarded as being off.

The signal flowing to the ground terminal is converted into a thermal component by the resistors R1 and R2, and the capacitors C1 and C2 block a part of the isolated signal from being returned to the switch parts 125 and 130.

The first switch unit 125 and the second switch unit 130 alternately connect a signal path to the third switch unit 135, and the third switch unit 135 may include the first switch unit 125 and Since the signal path of the second switch unit 130 selects its own signal path, the feedback signal is isolated when the received signal is transmitted to the mixer unit 145 and is received when the feedback signal is transmitted to the mixer unit 145. The signal is cut off.

Since the three switch units 125, 130, and 135 operate in synchronization with each other, signal separation characteristics are improved, noise mixing is minimized, and insertion loss is reduced.

The mixer unit 145 generates an intermediate frequency signal by synthesizing the received signal or feedback signal transmitted from the third switch unit 135 with the oscillation frequency signal transmitted from the phase synchronization circuit unit 140.

Referring to FIG. 1, the phase synchronization circuit unit 140 receives a division control signal from the control unit 165 and divides (divides) a plurality of oscillation frequencies at predetermined intervals within the RFID frequency range according to the control signal. Generate a signal.

Since the RFID reader network measurement system 100 according to the present invention must process various measurement items at once, the oscillation frequency signal is more advantageously divided into tighter bands. For example, the oscillation frequency signal has a reference when frequency hopping. It may be divided into hopping intervals between channels.

In this case, the phase synchronization circuit 140 may generate an oscillation frequency signal having an interval of 200 KHz from about 900 MHz band to about 1 GHz band.

The mixer unit 145 synthesizes the received received or feedback signal with a plurality of oscillation frequency signals (input from the "LO" stage) to generate an intermediate frequency signal and sequentially transfers the generated intermediate frequency signal (" To the filter 150 via the " DET &quot;

The filter 150 blocks the signal of the noise component mixed with the intermediate frequency signal during synthesis, and the first PA 155 amplifies the filtered signal to meet the processing standard of the detector 160.

The detector 160 generates a digital signal differentiated according to the power level of the amplified intermediate frequency signal, for example, it may be configured to include a log amplifier.

The log amplifier detects the level by outputting the intermediate frequency signal in analog state as a DC voltage signal, which can be received by directly outputting the intermediate frequency signal as a DC voltage signal proportional to the decibel value. The signal sensitivity range of the power level can be extended.

3 is a graph measuring a signal processed by the sensing unit 160 of the RFID reader network measurement system 100 according to an embodiment of the present invention.

Referring to FIG. 3, a form in which the digital signal generated by the detector 160 is measured according to a frequency band (depending on the type of oscillation frequency signal) is measured. An interval A between the frequency bands is about. It is measured in 20MHz units and it can be seen that the intermediate frequency signal is generated as a digital signal of various voltage levels.

Accordingly, the controller 165 may interpret the digital signal by reflecting more various measurement items.

The controller 165 analyzes digital signals sequentially transmitted from the detector 160 to generate an analysis value of an RFID communication environment. The analysis value information includes, firstly, whether an interference phenomenon occurs between frequency channels. Whether there is a fine oscillation signal between the divided frequency bands as a test object, third, whether there is a feedback signal, fourth, power values of the received signal and the feedback signal, and fifth, frequency hopping, that is, channel hopping. Sixth, reflection coefficients, VSWR (Voltage Standing Wave Ratio) figures, modulation figures, noise figures, distortion figures, and power figures.

For example, VSWR may be calculated by Equation 1.

The control unit 165 includes an analysis table for analyzing the digital signal transmitted from the sensing unit 160 to generate the analysis numerical information, and converts the signal format to analyze the code of the digital signal. Process filtering operations to extract the necessary information.

The controller 165 may be implemented using a field programmable gate array (FPGA) circuit or a digital signal processing (DSP) circuit.

The graphical user interface (GUI) processor 170 includes a program module for analyzing the analysis numerical information, and provides the analysis numerical information as a user interface screen.

The function of the controller 165 to analyze the digital signal and generate the analysis numerical information is possible by including a programmed circuit, which may be provided on the part of the GUI processor 170.

4 is a diagram illustrating a screen processed by the GUI processing unit 170 of the RFID reader network measurement system 100 according to an embodiment of the present invention.

Referring to FIG. 4, the GUI processor 170 may view a screen in which a received signal measured for each frequency band is provided graphically, and vertices B indicated by dots on a displayed signal curve mean power values. Even if only the power value is analyzed, it is possible to determine the power value of the received signal, whether the interference signal is mixed, whether the normal frequency hopping is processed, and the like.

RFID reader network measurement system 100 according to the present invention, such as a network management system installed in an external terminal equipped with a program for processing the analysis value information generated by the control unit 165 to provide a user interface, such as a central center It is interoperable with an external terminal and includes a connection unit 175 to be connected to the external terminal.

That is, the function of the GUI processing unit 170 is implemented in the external terminal, and the control unit 165 transmits the analysis numerical information to the external terminal through the connection unit 175, so that the measurer checks the measurement result on the external terminal and enters the database. It can be managed.

The connection unit 175 is connected to an external terminal through a wired / wireless network, for example, may be implemented as a wireless LAN access device.

The wireless LAN access device establishes a wireless communication channel through the identification / authentication / encryption process with the wireless access device installed in the external terminal, receives the analysis numerical information from the controller 165, and transmits the analysis numerical information to the external terminal.

The wireless LAN access device may be implemented in the form of a LAN card, an access point (AP), or the like, and the AP may be several Mbps to several dozen Mbps using an ISM (Indutrial, Scientific and Medical) band region of a 2.4 GHz frequency band without a license. It is a wireless communication device that can form a network of speed.

These APs follow the high-speed 802.11 standard of DSSS (Direct Sequence Spread Spectrum) method, because the existing AP supporting 2Mbps speed and the latest AP supporting 11Mbps speed coexist and move to high speed 11Mbps environment easily. This is because there is compatibility between different products.

5 is a diagram illustrating an external terminal 10 interoperable with the RFID reader network measurement system 100 according to an embodiment of the present invention, and FIG. 6 is interoperable with an RFID reader network measurement system according to an embodiment of the present invention. FIG. 1 is a diagram illustrating a user interface screen C provided by the external terminal 10.

Referring to FIG. 5, a notebook is used as an external terminal 10, and the notebook 10 is connected to a mobile phone 20 having a wireless LAN connection function to perform communication with the connection unit 175.

The notebook 10 is a computer in which a function of the GUI processor 170 is programmed and a database system for managing analysis numerical information is mounted.

Referring to FIG. 6, a database management screen C provided by the notebook 10 is illustrated, and the measurer can easily and quickly grasp the propagation environment of the reader through the management screen C. It can be deployed efficiently.

The RFID reader network measurement system 100 according to the present invention may be interlocked with a system for transmitting a measurement RF signal in order to determine an installation position of a reader in advance, and FIG. 7 is an RFID reader network according to an embodiment of the present invention. Fig. 1 is a block diagram schematically showing the components of the measurement RF transmission system 50 that is linked to the measurement system.

According to FIG. 7, the measurement RF transmission system 50 includes a control unit 51, an oscillation frequency circuit 52, a low pass filter (LPF) 53, a second PA 54, an attenuator 55, and an antenna 56. )

The oscillation frequency circuit 52 includes an oscillator, a phase synchronization circuit, and the like to generate a measurement signal of an RFID communication band, and the LPF 53 removes a noise signal of a mixed high frequency component in the process of generating the measurement signal.

The second PA 54 amplifies the filtered measurement signal to a transmittable size, and the attenuator 55 sequentially converts the power level of the measurement signal into a signal having various power values.

At this time, the controller 51 controls the oscillation frequency circuit 52 to generate a stable (no frequency fluctuation) measurement signal, and transmits a control signal to the attenuator 55 so that the attenuator 55 adjusts the power level. Make various adjustments.

For example, the attenuator 55 may have 100 dB, 90 dB, 80 dB... That is, it is possible to generate a measurement signal with a different power level at intervals of 10dB, the measurement signal transmitted in this way is received by the RFID reader network measurement system 100 according to the present invention, the signal processing in the same manner as described above Can be.

The control unit 51 generates analytical numerical value information by a measurement signal processed as a digital signal. Since the measurement signal has a power level adjusted in advance for accurate measurement, an accurate analytical value can be obtained and isolation between signals Items of the above-described analysis numerical information, such as an isolation, a reception sensitivity, and a recognition rate, may be calculated.

For example, if a reception sensitivity of 60 dB or less is measured as a result of analyzing the measurement signal, the area where the measurement RF transmission system 50 is located may be determined to be unsuitable for installing the reader.

Although the present invention has been described above with reference to the embodiments, these are only examples and are not intended to limit the present invention, and those skilled in the art to which the present invention pertains may have an abnormality within the scope not departing from the essential characteristics of the present invention. It will be appreciated that various modifications and applications are not illustrated. For example, each component specifically shown in the embodiment of the present invention can be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

According to the RFID reader network measurement system according to the present invention, since an RFID signal can be accurately detected and analyzed for each frequency band, the RFID network is based on analysis results such as modulation value, distortion value, noise value, power value, and VSWR value. It is effective to build and operate the system efficiently.

In addition, according to the present invention, various items can be easily and quickly measured in consideration of the characteristics according to the RFID signal band, the circuit characteristics, the characteristics of the modulation and demodulation standard, etc., and can be managed in a database in conjunction with an external system so that the measurement cost can be measured. In addition, there is an effect that can reduce the skill, effort, time, etc. for the equipment.

Claims (13)

A phase synchronization circuit unit generating a plurality of oscillation frequency signals divided at predetermined intervals within an RFID frequency range; A mixer unit which sequentially synthesizes the signal received through the antenna with the oscillation frequency signal and converts the signal into a plurality of intermediate frequency signals; A detector configured to generate a digital signal differentiated according to the power level of the intermediate frequency signal; And RFID reader network measurement system including a control unit for analyzing the digital signal to generate the analysis numerical information of the RFID communication environment. The method of claim 1, A first coupling unit coupling the received signal; A second coupling unit coupling a signal fed back from the antenna; A first switch unit configured to switch the coupled received signal to the mixer unit; And And a second switch unit for switching the coupled feedback signal to the mixer unit. The method of claim 1, wherein the control unit And an RFID reader network measuring system for transmitting the control signal to generate the divided plurality of oscillation frequency signals. The method of claim 1, wherein the detection unit RFID reader network measurement system including a log amplifier. The method of claim 1, RFID reader network measurement system including a graphical user interface (GUI) processing unit for providing the analysis numerical information transmitted from the control unit to a user interface screen. The method of claim 1, RFID terminal network measurement system including an external terminal equipped with a program for analyzing the analysis numerical information and a connection unit connected to the control unit for transmitting the analysis numerical information to the external terminal. The method of claim 1, wherein the phase synchronization circuit unit RFID reader network measurement system for generating a plurality of oscillation frequency signals divided by RFID frequency channels. The method of claim 1, wherein the control unit The analysis numerical information related to at least one of interference among signals divided at predetermined intervals within the RFID frequency range, presence of a fine oscillation signal, presence of a feedback signal, power of a received signal, and hopping operation between frequency channels; RFID reader network measurement system for generating a. The method of claim 2, wherein the control unit And analyzing the digital signal according to the received signal and the feedback signal to generate the analysis numerical information of at least one of reflection coefficient and VSWR (Voltage Standing Wave Ratio) value. The method of claim 6, wherein the connection portion RFID reader network measurement system connected to the external terminal via a wireless LAN. The method of claim 2, And a third switch unit configured to switch the received signal transmitted from the first switch unit or the feedback signal transmitted from the second switch unit to the mixer unit. The method of claim 1, And an RFID reader network measurement system interworking with a system for transmitting a measurement signal having a plurality of power levels, and receiving the measurement signal to generate the analysis numerical information. The system of claim 1, wherein the system for transmitting the measurement signal is And an attenuator to generate a measurement signal having the plurality of power levels.

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