KR101004531B1 - RFID Reader Using Space-Time Method - Google Patents

Abstract

The present invention relates to an RFID reader and a transmission / reception method using a space-time (diversity), a signal distribution unit for copying one RFID transmission signal into a plurality of signals and separating and outputting each of the plurality of paths, in the signal distribution unit A transmission antenna unit including a plurality of transmission antennas receiving the RFID transmission signal and transmitting the RFID transmission signal toward an external tag, and receiving a signal returned from the tag in response to the RFID transmission signal transmitted from the transmission antenna unit The receiving antenna unit includes a receiving antenna unit including a plurality of receiving antennas and the starting point of the signal returned from the tag by the zero crossing method based on the last received signal among the signals returned from the tag received through the receiving antenna unit. And a signal synthesizing unit for synthesizing the signal into one tag identification signal. It shall be.

RFID, Wireless Identification, Reader, Space-Time Method

Description

RDF reader using space-time method {Spatio-Temporal RFID reader}

The present invention relates to an RFID reader and a transmission / reception method using space-time (diversity), and to an RFID reader using space-time coding to increase the recognition rate of an RFID reader antenna by using a plurality of transmission / reception antennas.

The present invention relates to an RFID reader and a transmission / reception method using radio frequency identification (RFID) technology, and in particular, an RFID reader capable of increasing a transmission / reception rate of a signal through a space-time method using a plurality of transmission antennas and a reception antenna; It relates to a transmission and reception method.

Due to the development of information and communication technology, interest in ubiquitous services that can maximize user convenience is increasing. In general, the ubiquitous environment refers to a space where all things such as digital homes, offices, buildings, telematics, and intelligent robots are connected to the network and perform computing functions regardless of time and place.Ubiquitous service is provided under ubiquitous environment. Says any service that becomes. Looking at such ubiquitous, the existing IT technology allows humans to adapt to computing technology, while ubiquitous service is a simple tool for improving productivity in daily work and life. It means that the paradigm will be changed to that level.

The next generation technology of the ubiquitous network technology is RFID technology, and among them, RFID technology introduced in commerce is representative. In general, a commercial RFID system includes an RFID tag attached to a product and embedded with detailed information, an RFID reader that reads information of the electronic tag using RF communication, an information server that collects information from the RFID reader, and builds a database. The RFID tag attached to the product passes through the area where the RFID reader is located and transmits the information by using RF communication, so the logistics and distribution management of the product distribution, assembly, price change, sale, etc. are efficiently processed. Provides a foundation to be

1 is a block diagram of a conventional RFID reader 100.

Referring to FIG. 1, a conventional RFID reader includes a transmission modulator 110, a transmission antenna 120, a reception antenna 130, a reception demodulation unit 140, and a host 150.

The transmission modulator 110 modulates digital data for obtaining identification information of a desired tag into an RF signal and transmits the digital data to the transmission antenna 120. The transmission antenna 120 receives the RF signal from the transmission modulator 110 and transmits the RFID transmission signal toward the tag antenna. The tag receiving the RFID transmission signal generates identification information of a tag stored in a memory through a tag control unit, modulates the tag identification information into an RF signal through a tag antenna, and transmits the identification information. The receiving antenna 130 receives tag identification information transmitted from a tag through a wireless channel of the 800 MHz to 900 MHz band and transmits it to the receiving demodulation unit 140. The reception demodulator 140 decodes the received tag identification information and delivers it to the host. The host 150 processes tag identification information received from the reception demodulator.

The RF signal used in the tag and the reader in the RFID wireless device is represented by various signal components due to factors such as radio wave attenuation, multipath loss, interpier and Doppler effects. In addition, among RFID technologies, a receiving end of an RFID reader is generally implemented through envelope detection using ASK (Amplirtude Shift Keying), FSK (Frequency Shift Keying), or PSK (Phase Shift Keying) modulation.

According to the conventional RFID radio apparatus as described above, there is a disadvantage in that the bit error rate is lowered and thus the data recognition rate is lowered, and since the target is a tag moving at a high speed, the radio wave environment is severely changed and the received signal is changed according to the external environment change. There is a problem that large changes occur.

Therefore, in order to solve the above problems, the present invention intends to increase the recognition rate of a signal by using a space-time (diversity) method of the transmission antenna and the reception antenna of the RFID reader.

SUMMARY OF THE INVENTION An object of the present invention for solving the above problems is to provide an apparatus and method for increasing the transmit / receive rate of a signal using a space-time method so that the RFID transceiver includes a plurality of transmit antennas and a plurality of receive antennas. Is in.

In order to solve the above problems, an RFID reader according to an embodiment of the present invention copies a single RFID transmission signal into a plurality of signals and separates and outputs the RFID transmission signals in a plurality of paths, respectively. A transmission antenna unit including a plurality of transmission antennas for receiving and transmitting the RFID transmission signal toward an external tag, and a plurality of reception receiving signals transmitted from the tag in response to the RFID transmission signal transmitted from the transmission antenna unit One tag by matching the starting time point of the signal returned from the tag by the zero crossing method based on the last received signal among the signals returned from the receiving antenna unit including the antenna and the tag received through the receiving antenna unit. It may include a signal synthesizer for synthesizing the identification signal.
According to an aspect of an exemplary embodiment of the present invention, a first band pass filter may be connected to an input terminal of the signal distribution unit.
According to an aspect of an exemplary embodiment of the present invention, a second band pass filter may be connected to an output terminal of the signal synthesis unit.
According to an aspect of an embodiment of the present invention can be characterized in that a power amplifier is connected to the transmit antenna portion and the RFID transmission signal is transmitted to the transmit antenna portion through the power amplifier.
According to an aspect of an exemplary embodiment of the present invention, a low noise amplifier may be connected to the reception antenna unit, and a signal carried from an external tag may be transmitted to the low noise amplifier through the reception antenna unit.
In another embodiment of the present invention, an RFID transmission / reception method includes a first step of digitally copying one RFID transmission signal in a signal distribution unit and separating and outputting the signal into a plurality of paths, the transmission antenna unit including a plurality of transmission antennas. The second step of receiving the RFID transmission signal to transmit the RFID transmission signal toward an external tag at a receiving antenna unit including a plurality of receiving antennas in response to the RFID transmission signal transmitted from the transmitting antenna unit in the tag A third step of receiving a signal returned from the signal and a start of the signal returned from the tag by a zero crossing method based on the last received signal among the signals returned from the tag received through the reception antenna unit in the signal synthesis unit; And a fourth step of synthesizing the view points into a single tag identification signal.
According to an aspect of another embodiment of the present invention, the second step includes amplifying and outputting an energy level from a power amplifier connected to each path by a plurality of RFID transmission signals passing through the signal distribution unit, and including a plurality of transmission antennas. And receiving the RFID transmission signal from a transmitting antenna unit and transmitting the RFID transmission signal toward an external tag.
According to an aspect of another embodiment of the present invention the third step is receiving a signal carried from the tag in response to the RFID transmission signal transmitted from the transmitting antenna unit in a receiving antenna unit including a plurality of receiving antennas; The signal transmitted from the plurality of tags passing through the plurality of receiving antennas may be characterized in that it comprises a step of removing noise from the low noise amplifier connected to each path and transmitted to the signal synthesizer.

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According to the RFID reader and the method for transmitting and receiving an RFID signal using the same according to the present invention configured as described above, by using a plurality of transmitting antennas and a plurality of receiving antennas the strength of the signal passing through the transmitting antenna unit and the receiving antenna unit of the antenna By amplifying the number, there is an advantage of increasing the transmit / receive rate of the signal.

DETAILED DESCRIPTION Hereinafter, a detailed description of a preferred embodiment of the present invention will be described with reference to the accompanying drawings. It should be noted that the same reference numerals and the same elements among the drawings are denoted by the same reference numerals and symbols as much as possible even though they are shown in different drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

2 is a block diagram of an RFID reader including a plurality of transmitting and receiving antenna units as an embodiment of the present invention.

Referring to FIG. 2, the RFID reader 200 according to an embodiment of the present invention may include a transmitting antenna unit 210, a power amplifier 220, a signal distribution unit 230, a first band pass filter 240, and a receiving antenna. The unit 250 includes a low noise amplifier 260, a signal synthesizer 270, a second band pass filter 280, and a host 290.

The transmission antenna unit 210 includes a plurality of transmission antennas, and transmits an RFID transmission signal toward the tag antenna through various paths through the plurality of transmission antennas.

The power amplifier 220 includes a plurality of power amplifiers, and one power amplifier is connected to each of the transmission antennas, respectively. The power amplifier 220 amplifies the weak size of the RFID transmission signal divided into a plurality of signals in the signal distribution unit 230 to increase the energy transfer efficiency. In addition, the power amplifier 220 is configured to pass through the RFID transmission signal just before being transmitted through the transmission antenna unit to maximize the amplification effect of the signal size.

The signal distributor 230 is connected to the power amplifier 220 and performs a function of receiving one RFID transmission signal and separating the signal into a plurality of paths. The signal distributor 230 operates digitally to copy one RFID transmission signal into a plurality of RFID transmission signals while maintaining the size of the signal. The plurality of RFID transmission signals are output in different paths so that each signal can be divided into a plurality of transmission antennas in the signal distribution unit 230. In addition, the signal distributor 230 may control the time difference between the plurality of RFID transmission signals.

The first band pass filter 240 is connected to an input terminal of the signal distribution unit 230, and only a signal of a corresponding frequency band is left in the RFID transmission signal input to the first band pass filter 240. By removing the signal of the function to increase the transmission rate of energy. In addition, the first band pass filter 240 may be configured to pass before the RFID transmission signal is divided into a plurality of signals to use only one band pass filter.

The receiving antenna unit 250 includes a plurality of receiving antennas, and receives a tag identification signal transmitted from a tag antenna through a plurality of paths through the plurality of receiving antennas to increase the reception rate of the signal. That is, when the signal strength of the tag received through one reception antenna is A, the signals received by the N reception antennas are A * N in size, thereby improving the performance of receiving the identification signal of the tag.

The low noise amplifier 260 includes a plurality of low noise amplifiers, and one low noise amplifier is connected to each of the plurality of receiving antennas. The low noise amplifier 260 may remove the noise included in the weak tag identification signal to increase the reception rate of the signal. In addition, the low noise amplifier 260 is directly connected to the receiving antenna unit 250 so that components such as noise can be removed immediately after the tag identification signal is received by the RFID reader. It is possible to have a signal of a predetermined size or more before being transmitted to 270).

The signal synthesizing unit 270 is connected to the low noise amplifier 260 and performs a function of synthesizing the tag identification signals received through the plurality of receiving antennas into a single tag identification signal and transmitting the same to the host 290. The plurality of tag identification signals transmitted to the plurality of receiving antennas are received with a time difference according to a distance from a tag, a reflection angle, and the like. Accordingly, the signal synthesizing unit 270 controls the time difference between the plurality of tag identification signals to match the starting point to synthesize one tag identification signal. A zero-crossing method may be used as a method of matching the start time.

The zero-crossing method is an on / off control method for detecting a zero point, which is a point where a signal is generated. By detecting the zero point as described above, a noise-free control is possible, and the signal synthesizing unit 270 may synthesize a single tag identification signal by matching a time point when each of the plurality of tag identification signals passes the zero point. have.

The second band pass filter 280 is connected to an output terminal of the signal synthesizing unit 270, and leaves only a signal of a corresponding frequency band in one tag identification signal transmitted from the signal synthesizing unit 270. The signal is removed to increase the reception rate of energy. In addition, the second band pass filter 280 may be configured to pass after a plurality of tag identification signals are synthesized into one tag identification signal to use only one band pass filter.

The host 290 is a computer having the ability to receive and process a request from another computer or user or to provide a specific service. The host 290 processes a tag identification information transmitted from the tag.

Hereinafter, a method of transmitting and receiving a signal according to the present invention will be described.

In order to output the RFID transmission signal from the RFID reader to the tag, the RFID transmission signal to be transmitted to the tag to be processed by the host is transferred to the first band pass filter. The first band pass filter leaves a signal of a required frequency band in the RFID transmission signal, and removes a signal of a frequency band other than that and transmits the signal to a signal distribution unit. The signal distribution unit receives a single RFID transmission signal and copies a plurality of RFID transmission signals having the same signal size in a digital manner so that signals can be divided into a plurality of transmission antennas. Each of the plurality of RFID transmission signals is output by being distributed to each of the paths so as to be transmitted to the respective transmission antennas by the signal distribution unit. The plurality of RFID signals passing through the signal distribution unit respectively amplify the energy level of the weak RFID transmission signal while passing through the power amplifier. The plurality of RFID transmission signals amplified by the magnitude of the energy in the power amplifier are transmitted through the plurality of transmission antennas toward the tag antenna.

The tag receives a plurality of RFID transmission signals using the tag antenna, generates a tag identification signal stored in a memory through a tag control unit, and transmits the tag identification signal to a receiver of the RFID reader. The receiving unit of the RFID reader includes a plurality of receiving antennas, and receives the tag identification signal through a plurality of paths through the plurality of receiving antennas. The plurality of tag identification signals passing through the reception antenna unit are transmitted to the plurality of low noise amplifiers, respectively, to remove noise and the like included in the tag identification signal to increase the reception rate of the signal. The plurality of tag identification signals passing through the plurality of low noise amplifiers are transmitted to the signal synthesis unit. The signal synthesizing unit synthesizes one tag identification signal by matching start points of a plurality of tag identification signals received from a plurality of receiving antennas.

The tag identification signals transmitted to the plurality of reception antennas are transmitted to the plurality of reception antennas at different times due to a distance between the tag and the reception antenna, a path through which the tag identification signal is transmitted, and a reflection angle when the tag identification signal is transmitted. do. The signal distributing unit synthesizes a plurality of tag identification signals transmitted at different time points by matching start points to synthesize one tag identification signal. As a method of matching the start time, a zero-crossing method may be used. The signal distributor may improve the reception rate of the signal by delaying the first tag identification signal and synthesizing the starting points of the plurality of tag identification signals into one tag identification signal.

 The tag identification signal output from the signal synthesizing unit is transmitted to the second band pass filter, leaving only the signal of the required frequency band of the tag identification signal, and removing signals of other frequency bands, and transmitting the signal to the host.

3 is a diagram illustrating a process of transmitting and receiving an identification signal of a tag using an RFID reader including a plurality of transmit and receive antennas according to an exemplary embodiment of the present invention.

Referring to FIG. 3, an RFID transmission signal transmitted from a host passes only a signal in a frequency band while passing through a first band pass filter (S310). The RFID transmission signal output from the first band pass filter is input to the signal distribution unit, and the signal is copied and distributed to the plurality of RFID transmission signals through a digital method so as to be transmitted to each of the plurality of transmission antennas (S320). The plurality of RFID transmission signals distributed in the signal distribution unit amplify the energy level in the power amplifier (S330). The RFID transmission signal amplified by the power amplifier is transmitted through a transmission antenna unit including a plurality of transmission antennas (S340). When the tag identification signal is returned in response to the RFID transmission signal (S350), the tag identification signal is received by the reception antenna unit including a plurality of reception antennas (S360). The received plurality of tag identification signals are respectively transmitted to the low noise amplifier to remove noise components included in the tag identification signal (S370). The plurality of tag identification signals from which the noise component is removed are transmitted to the signal synthesizing unit, and are synthesized into one tag identification signal by matching the starting time points (S380). One tag identification signal synthesized by the signal synthesizing unit passes through a second band pass filter and passes only a signal having a required frequency band and is transmitted to the host (S390).

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims below but also by the claims and equivalents thereof.

1 is a block diagram of a conventional RFID reader (reader).

2 is a block diagram of an RFID reader including a plurality of transmit and receive antenna units according to an embodiment of the present invention.

3 is a view illustrating a signal transmission and reception process according to an embodiment of the present invention.

Claims (10)

A signal distribution unit for copying one RFID transmission signal into a plurality of signals and separating and outputting each of the plurality of paths; A transmission antenna unit including a plurality of transmission antennas receiving the RFID transmission signal from the signal distribution unit and transmitting the RFID transmission signal toward an external tag; A reception antenna unit including a plurality of reception antennas for receiving a signal returned from the tag in response to an RFID transmission signal transmitted from the transmission antenna unit; And A signal synthesizing unit for synthesizing one tag identification signal by matching the starting time points of the signals returned from the tag by a zero crossing method based on the last received signal among the signals returned from the tag received through the receiving antenna unit. RFID reader comprising a. The method of claim 1, And a first band pass filter connected to an input terminal of the signal distributor. The method of claim 1, And a second band pass filter connected to an output terminal of the signal synthesis unit. The method of claim 1, And a power amplifier connected to the transmission antenna unit, and an RFID transmission signal is transmitted to the transmission antenna unit through the power amplifier. The method of claim 1, A low noise amplifier is connected to the receiving antenna unit, and a signal carried from the external tag is transmitted to the low noise amplifier through the receiving antenna unit. delete A first step of digitally copying one RFID transmission signal from the signal distribution unit and separating the RFID transmission signal into a plurality of paths; A second step of receiving the RFID transmission signal from a transmission antenna unit including a plurality of transmission antennas and transmitting the RFID transmission signal toward an external tag; A third step of receiving a signal carried from the tag in response to an RFID transmission signal transmitted from the transmission antenna unit in a reception antenna unit including a plurality of reception antennas; And The signal synthesizing unit synthesizes one tag identification signal by matching the starting time point of the signal returned from the tag by the zero crossing method based on the last received signal among the signals returned from the tag received through the receiving antenna unit. RFID transmitting and receiving method comprising a fourth step. The method of claim 7, wherein The second step is Amplifying and outputting an amount of energy from a power amplifier connected to each path of the plurality of RFID transmission signals passing through the signal distribution unit; And And receiving the RFID transmission signal from a transmission antenna unit including a plurality of transmission antennas and transmitting the RFID transmission signal toward an external tag. The method of claim 7, wherein The third step is Receiving a signal carried from the tag in response to an RFID transmission signal transmitted from the transmission antenna unit in a reception antenna unit including a plurality of reception antennas; And And a signal carried from the plurality of tags passing through the plurality of receiving antennas is removed from a low noise amplifier connected to each path and transmitted to the signal synthesizing unit. delete

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