KR101283175B1 - Multi-reader hopping check system - Google Patents

Abstract

The multi-leader hopping check system according to the present invention relates to a system for managing a plurality of RFID readers, the plurality of antennas for receiving signals from the reader, and a first path for sequentially transmitting the signal paths of the antennas by switching to a single path. At least one first group comprising a switch unit; And a first separator configured to sequentially switch signals transmitted from the first switch unit of the first group by a single path, and to detect power levels of the signals transmitted from the first separator to generate a detection signal. A reader signal sensing device including one or more second groups including; And a reader control device connected to the reader signal detection device and configured to determine whether an interference signal for each RFID channel is present based on the detection signal and to transmit a frequency hopping control signal to the reader.

According to the present invention, by analyzing a plurality of reader signals at the same time can accurately identify the interference channel, and can control the channel hopping operation of the reader to improve the recognition distance, reception sensitivity, recognition rate of the RFID signal There is. In addition, according to the monitoring result of the leader signal, a plurality of readers can be efficiently arranged, and there is an effect that it is not necessary to have a complicated control system.

Description

Multi-reader hopping check system

1 is a view schematically illustrating a configuration in which a component of a multireader hopping check system according to an embodiment of the present invention is connected through a network.

2 is a block diagram schematically illustrating components of a leader managed by a multireader hopping check system according to an embodiment of the present invention.

Figure 3 is a block diagram schematically showing the components of the reader signal detection device of the multi-leader hopping check system according to an embodiment of the present invention.

Figure 4 is a block diagram schematically showing the components of the signal detection unit of the reader signal detection apparatus according to an embodiment of the present invention.

5 is a block diagram schematically illustrating components of a reader control apparatus according to an embodiment of the present invention.

FIG. 6 is a graph illustrating a result of analyzing collected reader signals for each frequency channel by a reader control apparatus according to an exemplary embodiment of the present invention. FIG.

7 is a data table showing a frequency channel managed by a reader control apparatus according to an embodiment of the present invention.

Description of the Related Art

100: multi-leader hopping check system 120: reader signal detection device

121: antenna 122: first switch unit

123: second switch unit 124: first separator

125: signal detection unit 126: third switch unit

127: second separator 128: attenuator

140: reader control unit 141: signal analysis unit

142: reader control unit 143: interface unit

144: display device 200: reader

The present invention relates to a multireader hopping check system.

Nowadays, ubiquitous network technology is attracting attention of many people. Ubiquitous network technology means a technology that makes it possible to connect to various networks smoothly regardless of time and place.

As an example of such a ubiquitous network technology, RFID technology can be cited. In general, an RFID system is composed of a reader attached to an article and reading information of a tag or tag with detailed information using RF communication. Tags pass through the area where the reader is located and transmit information using RF communication, thus providing a basis for efficient management of logistics / distribution management such as distribution, assembly, price fluctuation and sales of the product.

The RFID system is generally implemented through envelope detection using an amplitude shift keying (ASK) modulation scheme. According to a conventional design scheme, a signal recovery rate is low.

In particular, in the case of the RFID reader, the radio wave environment is severely changed due to the tag moving at a high speed, and a change in the reception signal is greatly generated according to the external environment change (for example, the tag signal generated when the tag is moved). Phase shift, etc.), in particular frequency interference between RFID readers, has a significant effect on the recognition rate of RFID tags.

For example, when there are many tags in a region where a plurality of RFID readers are installed, tag signals using the same frequency band can be simultaneously received by the RFID readers. In this case, an interference phenomenon occurs between the tag signals, The signal can not be processed and the data recognition rate is further lowered.

In addition, when the transmission signal of another RFID reader or its transmission signal is transmitted to the receiving end of the RFID reader, the transmission signal acts as an interference signal, making it difficult to process the tag (reception) signal.

The RFID frequencies are low frequency (LF) such as 125 KHz and 135 KHz, high frequency (HF) such as 13.56 MHz, ultra high frequency (UHF) in 433 MHz and 900 MHz band and microwave in 2.45 GHz band. The 900 MHz frequency band is expected to be widely used due to its advantages such as small size, long recognition range, and ability to distinguish multiple tags.

However, since the frequency of the 900 MHz band has a narrow overall frequency bandwidth and a small number of carriers, the influence of an external interference signal including a transmission signal or interference between the tag signals may be recognized as a more serious problem.

In order to minimize the influence of the frequency interference phenomenon, a frequency hopping method is generally used. A typical frequency hopping method is Frequency-Hopping Spread Spectrum (FHSS), which uses 23 independent channels and the entire channel. It randomly leaps channels by "Random Hopping Sequence" and transmits and receives data.

However, in the FHSS scheme, if the hopped channel is used by another RFID reader, it is difficult to completely exclude the inter-reader interference because a frequency collision occurs.

The present invention monitors a communication channel of a reader in which an interference signal exists and controls a reader by identifying a channel where an interference phenomenon occurs, so that a plurality of readers operating in a frequency hopping method can stably communicate. Provides a hopping check system.

The present invention provides a multi-reader hopping check system that can monitor the signals received from a plurality of readers to monitor the presence or absence of leader signals.

The multi-leader hopping check system according to the present invention relates to a system for managing a plurality of RFID readers, the plurality of antennas for receiving signals from the reader, and a first path for sequentially transmitting the signal paths of the antennas by switching to a single path. At least one first group comprising a switch unit; And a first separator for sequentially switching signals transmitted from the first switch unit of the first group by a single path, and detecting a power level of the signal transmitted from the first separator to generate a detection signal. A reader signal sensing device including at least one second group including a portion; And a reader control device connected to the reader signal detection device and configured to determine whether an interference signal for each RFID channel is present based on the detection signal and to transmit a frequency hopping control signal to the reader.

Hereinafter, a multireader hopping check system according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram schematically illustrating a configuration in which the components of the multireader hopping check system 100 according to an embodiment of the present invention are connected through a network.

1, the multireader hopping check system 100 according to an embodiment of the present invention includes a reader signal sensing device 120 and a reader control device 140. Receives a signal from the reader 200 to detect the power level and generate a detection signal.

The reader control device 120 is connected to the reader signal detection device, receives the detection signal to determine the presence or absence of interference signals for each RFID channel, and transmits a frequency hopping control signal to the reader.

The reader 200 performs frequency hopping in an FHSS scheme to communicate with a tag (not shown). The FHSS scheme operates at an SNR of 12 dB using a phase shift keying (PSK) phase modulation technique. Unlike DSSS (Direct Sequence Spread Spectrum) method that uses overlapping channels, it uses 15 independent channels and randomly leaps and sends and receives data by "Random Hopping Sequence" over the entire channel.

However, even if the reader 200 is operated in the FHSS scheme, if the leap channel is used by another reader, it is difficult to exclude the interference between the readers because a frequency collision occurs.

On the other hand, the reader 200 according to the present invention receives the frequency hopping control signal from the reader control device 140, and can jump to another channel avoiding the channel where the interference phenomenon occurs, thereby stably performing RFID communication. .

In addition, since the reader control device 140 may monitor the reader signal by analyzing the detection signal transmitted from the reader signal sensing device 120, the reader control device 140 may not only control the operation of the reader 200, but also the reader ( 200 can be efficiently disposed, and thus, interference can be prevented from occurring between the readers 200 in advance.

The reader signal detection device 120 communicates with the reader 200 through an RFID channel, and the reader control device 140 is Wi-Fi (Wireless LAN), UWB (Ultra Wide Band), Bluetooth (Bluetooth), WiMax ( Wireless networks such as World Interoperability for Microwave Access, Zigbee, Dedicated Short Range Communication (DSRC) or wired such as Universal Asynchronous Receiver / Transmitter (UART), Internet (TCP / IP), Switch Hub, Serial / Parallel Cable, etc. The reader 200 may be connected to a network through a network.

The reader signal sensing device 120 and the reader control device 140 may be implemented on one system or may be implemented as an independent device (product), and when implemented as an independent device, may be connected through the various networks illustrated above. have.

In the embodiment of the present invention, the reader signal detection device 120 and the reader control device 140 is connected through a UART connection device.

Hereinafter, a reader signal sensing device 120 and a reader control device 140 will be described in detail with reference to the accompanying drawings. First, a reader 200 communicating with the multireader hopping check system 100 according to the present invention will be described. Take a quick look.

2 is a block diagram schematically illustrating the components of the leader 200 managed by the multireader hopping check system 100 according to an exemplary embodiment of the present invention.

Referring to FIG. 2, the reader 200 includes a reception antenna 205, a low noise amplifier (LNA) 210, a first filter 215, a mixer 220, a demodulator 225, and a phase synchronization circuit ( 230, a control unit 235, a modulator 240, a power amplifier module (PAM) 245, a second filter 250, and a transmission antenna 255.

The receiving antenna 205 receives a signal from a tag, and the LNA 210 suppresses and amplifies the noise component of the tag signal.

The first filter 215 filters the noise components mixed during the low noise amplification, and the mixer 220 mixes the oscillation frequency signal supplied from the phase synchronization circuit 230 with a tag signal to convert it into a baseband signal.

The demodulator 225 converts the baseband signal into a digital signal and transmits it to the control unit 235. The control unit 235 has a communication protocol to control wireless communication with the tag, interprets the digital signal, and stores tag information in memory. Store in and manage.

The modulator 240 synthesizes the digital signal (Command data) transmitted from the controller 235 and the oscillation frequency signal of the phase synchronization circuit 230 to modulate an analog signal, and the PAM 245 transmits the modulated signal. Amplify to the size possible.

The second filter 250 filters the amplified transmission signal to remove the signal of the unwanted component, and the transmission antenna 255 transmits the filtered signal to the tag.

At this time, the mixer 220, demodulator 225, modulator 240 is operated in the FHSS method, for example, processes the signal using 15 frequency channels in the 900 MHz band.

The controller 235 controls the phase synchronization circuit 230 to selectively supply oscillation frequency signals corresponding to 15 channels, so that the mixer 220 or the modulator 240 leaps 15 channels. Signals can be processed.

As described above, the controller 235 recognizes a channel having interference caused by the frequency hopping control signal transmitted from the reader control device 140, and allows the phase synchronization circuit 230 to selectively supply the oscillation frequency signal. Can be controlled.

3 is a block diagram schematically illustrating the components of the reader signal sensing device 120 of the multireader hopping check system 100 according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the reader signal detecting apparatus 120 receives a signal (a signal for a tag) from a plurality of readers 200 and generates a series of detection signals. 121, the switch 122, 123, 126, the separator 124, 127, the signal detecting unit 125, and the attenuator 128, the connection configuration thereof will be described as follows.

The plurality of antennas 121, the first switch unit 122, and the second switch unit 123 form a plurality of first groups, the first separator 124, the signal detecting unit 125, and the third switch. The unit 126, the second separator 127, and the attenuator 128 form a second group and are configured in plural.

For convenience of description, in the embodiment of the present invention, the one first group includes two antennas 121, one first switch portion 122, and a second switch portion 123, respectively, The switch unit 122 is provided as a single pole double throw (SPDT) element having two signal paths, and the second switch unit 123 is provided as a single pole single throw (SPST) element for opening and closing one signal path. Shall be.

In addition, the one second group is composed of one first separator 124, a signal detecting unit 125, a third switch unit 126, a second separator 127, and an attenuator 128, respectively. .

Here, the first separator 124 is connected to three first groups, and a circuit for branching signals input from three second switch units 123 belonging to each of the three first groups to one line, for example It may be provided as a four-way divider.

Of course, the first separator 124 may be connected to two or four or more first groups.

The two antennas 121 forming the first group receive a signal from the reader 200, and the first switch unit 122 switches the received signal to the second switch unit 123.

The second switch unit 123 is an element that opens and closes one signal path, and performs a function of turning on / off a signal input from the antenna 121 and the first switch unit 122 as necessary.

The first separator 124 of the second group receives signals from three second switch units 123 belonging to the first groups and transmits the signals to the signal detection unit 125 and the signal detection unit 125. Detects a power level of signals input from the first separator 124 and generates a plurality of detection signals.

Therefore, a large number of detection signals are generated from the signal detection unit 125 belonging to the second group, and the detection signals may be sequentially transmitted to the reader control device 140 through the second separator 127.

That is, the signal detector 125 transmits a detection signal to the second separator 127 of the second group to which it belongs, and the second separator 127 of the other second group to which it does not belong, thereby providing a large number of detection signals. It is possible to be transmitted to the reader control device 140 without collision, in this case, the third switch unit 126 of the second group is connected to the second separator 127 of the other second group, so that the detection signals are sequentially To be delivered. The third switch unit 126 may be provided as an SPST element for opening and closing one signal path.

The attenuator 128 adjusts the power of the detection signal transmitted from the second separator 127 to meet the signal processing standard of the reader control device 140.

That is, in the configuration according to the embodiment of the present invention, the second group connected to the three first groups is connected to the reader control apparatus 140, and the other second group connected to the other three first groups is also the reader control apparatus. Formed in connection with 140.

Such a configuration of the reader signal sensing device 120 is an embodiment, and three or more second groups may be provided and connected to two or four or more first groups.

4 is a block diagram schematically illustrating components of the signal detector 125 of the reader signal detection apparatus 120 according to an exemplary embodiment of the present invention.

Referring to FIG. 4, the signal detector 125 includes an amplifier / attenuator 125a, a mixer 125b, a low pass filter (LPF) 125c, a channel filter 125d, and a log amplifier 125e. .

The amplifier / attenuator 125a adjusts the power value of the received signal transmitted through the first separator 124 to meet the signal processing standard of the mixer 125b, and the mixer 125b receives the adjusted power value. The signal is synthesized with a Local Oscillator (LO) signal and converted into a signal of an intermediate frequency band.

At this time, it is necessary to monitor all 15 frequency channels of the received signal. Therefore, a local oscillation signal differentiated for each frequency channel is supplied from a local oscillation circuit (not shown). The mixer 125b receives sequentially differentiated local oscillation signals and generates received signals for each frequency channel as intermediate frequency signals.

The LPF 125c filters the mixed noise components in the mixing process, and the channel filter 125d filters each received signal transmitted for each frequency channel, for example, based on a 200 KHz band.

The log amplifier 125e performs a function of outputting a filtered intermediate frequency signal as a state capable of detecting a power level, that is, a DC voltage, and converting the intermediate frequency signal directly into a DC voltage signal proportional to the decibel value. The output expands the signal sensitivity range of power levels that can be received.

The detection signal generated as described above is transmitted to the reader control device 140 through the third switch unit 126, the second separator 127, and the attenuator 128.

5 is a block diagram schematically showing the components of the reader control device 140 according to an embodiment of the present invention.

Referring to FIG. 5, the reader control device 140 includes a signal analysis unit 141, a reader control unit 142, an interface unit 143, a display device 144, and a connection unit 145. The analysis unit 141 analyzes the detection signal transmitted from the reader signal detection device 120 to determine the existence of the interference signal and the degree of the interference phenomenon.

In addition, the signal analysis unit 141 processes the signal analysis information by analyzing the detection signal to determine the power value of the reader transmission signal, calculate a signal recognition rate, and the like.

The reader controller 142 generates a frequency hopping control signal based on signal analysis information, in particular, channel information generated by an interference signal, and transmits the generated frequency hopping control signal to the connection unit 145.

The connection unit 145 processes the frequency hopping control signal in accordance with the UART transmission standard, and transfers it to the control unit 235 of the reader 200.

Therefore, when the frequency hopping control signal is transmitted as described above, the reader 200 may adjust the oscillation frequency signal to hop to a channel where interference does not occur and communicate with the tag.

The interface unit 143 receives the signal analysis information from the signal analysis unit 141 to configure various display data, and the display device 144 provides the display data on a graphical user interface (GUI) screen.

Therefore, the measurer can monitor the analysis result of the signals received from the readers 200 through the screen provided by the display device 144, and can effectively arrange the readers 200 according to the monitoring results.

FIG. 6 is a graph illustrating a result of analyzing collected reader signals for each frequency channel according to an embodiment of the present invention, and FIG. 7 is a reader control device 140 according to an embodiment of the present invention. Is a data table showing a frequency channel managed by.

Referring to FIG. 6, signal analysis information processed by the interface unit 143 and the display device 144 on a graphic screen can be seen. The power value of the carrier signal is displayed on the left side of the screen, and the right side of the screen. On the other hand, the power level value (A) of the interference generated channel among the total 15 channels can be seen.

The reader controller 142 detects that an interference signal has been generated in channel 5 a1 and channel 10 a2 of the 15 channels based on the data table shown in FIG. A frequency hopping control signal for notifying of leap to channel 11 is generated and transmitted to the reader 200.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood that various modifications and applications not illustrated in the drawings are possible. For example, each component specifically shown in the embodiments of the present invention can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

According to the multi-leader hopping check system according to the present invention, it is possible to analyze a plurality of reader signals at the same time to accurately identify the channel in which interference occurs, and to control the channel hopping operation of the reader, so that the recognition distance, reception sensitivity, There is an effect that can improve the recognition rate.

In addition, according to the present invention, since the leader signal can be monitored by various items, it is possible to efficiently arrange a plurality of readers according to the analysis result, and there is no need to have a complicated control system for controlling the reader. .

Claims (8)

In a system for managing multiple RFID readers, At least one first group including a plurality of antennas for receiving signals from the reader, and a first switch unit for sequentially transmitting the signal paths of the antennas in a single path; And a first separator configured to sequentially switch signals transmitted from the first switch unit of the first group by a single path, and to detect power levels of the signals transmitted from the first separator to generate a detection signal. A reader signal sensing device including one or more second groups including; And And a reader control device connected to the reader signal detection device and configured to determine whether an interference signal for each RFID channel exists based on the detection signal and to transmit a frequency hopping control signal to the reader. The method of claim 1, wherein the first group And a second switch unit connected to a rear end of the first switch unit to open and close a signal path. The method of claim 1, wherein the second group Multi-reader hopping check system including a second separator for receiving the detection signal from the signal detection unit of the second group to which it belongs and another signal group of the second group does not belong to the reader control device . The method of claim 3, wherein the second group is And a third switch unit for opening and closing a signal line between the second separator and another second group of signal detection units. The method of claim 1, wherein the second group Multi-reader hopping check system including an attenuator connected to the rear end of the signal detection unit. The apparatus of claim 1, wherein the reader control device is A signal analysis unit for analyzing the detection signal to determine the existence of an interference signal for each RFID channel; A reader controller configured to generate a frequency hopping control signal based on channel information generated by the interference signal; And And a connection unit for transmitting the frequency hopping control signal to a reader. The apparatus of claim 1, wherein the reader control device is A signal analysis unit for processing one or more information among the presence or absence of interference signals for each RFID channel, power values of reader transmission signals, and signal recognition rates by analyzing the detection signals; And Multi-reader hopping check system including an interface unit for receiving the information from the signal analysis unit to provide a monitoring screen. The method of claim 1, wherein the leader When the frequency hopping control signal is transmitted to the multi-reader hopping check system for adjusting the oscillation frequency signal to hop to a channel free of interference and to communicate with the tag.

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