KR20070094324A - Transmitting and receiving system of radio frequency identification - Google Patents

Abstract

An RFID(Radio Frequency Identification) transmission/reception system is provided to implement a system easily for selectively processing different signals according to a protocol type by software in an RFID reader product interworking with a mobile terminal. A PLL(Phase Locked Loop) circuit unit(140) generates a reference frequency signal. A mixer unit of a reception BB processing unit(130) receives the reference frequency signal and generates a differentiated frequency signal according to an RFID protocol standard. A controller(170) transfers a control signal to the PLL circuit unit so that the reference frequency signal corresponding to the differentiated frequency signal can be generated according to frequency hopping.

Description

Transmitting and receiving system of Radio Frequency IDentification

1 is a block diagram schematically showing the overall components of an RFID transmission and reception system according to an embodiment of the present invention.

FIG. 2 is a data table comparing standards (when signals are transmitted from a reader to a tag) of communication protocols applicable to an RFID transmission / reception system according to an embodiment of the present invention.

3 is a data table comparing standards (when a signal is transmitted from a tag to a reader) applicable to an RFID transmission and reception system according to an embodiment of the present invention.

4 is a flowchart illustrating an operation process of an RFID transceiver system according to an exemplary embodiment of the present invention.

Figure 5 is a block diagram schematically showing the components of the phase synchronization circuit unit provided in the RFID transmission and reception system according to an embodiment of the present invention.

FIG. 6 is a block diagram schematically illustrating a configuration and connection relationship between a reception RF processor and a reception BB (BaseBand) processor included in an RFID transceiver system according to an exemplary embodiment of the present invention. FIG.

7 is a block diagram schematically illustrating the components of a transmitting RF processor and a transmitting BB processor of the RFID transceiver system according to an exemplary embodiment of the present invention.

<Explanation of symbols for main parts of drawing>

100: RFID transmission and reception system according to the present invention

105: first antenna 110: second antenna

120: receiving RF processing unit 130: receiving BB processing unit

140: phase synchronization circuit section 150: transmission BB processing section

160: transmitting RF processing unit 170: control unit

175: memory 180: interface circuit

185: button portion

The present invention relates to an RFID transceiver system for processing signals of different frequency bands in one system according to a protocol standard.

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.

As the next generation technology of the ubiquitous network technology, RFID technology may be cited. Among them, RFID technology introduced in commerce is representative.

In general, a commercial RFID system consists of an RFID tag attached to a product and embedded with details, an RFID reader that reads information of the RFID tag using RF communication, and the RFID tag attached to the product is located at which the RFID reader is located. Since information is transmitted through RF communication through the region, it provides a foundation for efficiently managing logistics / distribution such as distribution, assembly, price change, and sales of goods.

In particular, the reading distance and the recognition rate of the RFID tag are greatly influenced by the feedback component of the transmission power of the RFID reader. In the conventional RFID reader, the isolation between the transmitting end and the receiving end is reduced, and frequency separation is difficult. Since there is no way to suppress the feedback component, it is difficult to filter the frequency signal of the corresponding band.

Meanwhile, RFID communication has different frequency bands and signal systems according to UHF RFID protocols such as ISO 18000-6A, ISO 18000-6B, Electronic Product Code (EPC) Generation-0, EPC Generation-1, and EPC Generation-2. For example, ISO / IEC Type A uses 40 kHz, Type B uses 40 KHz or 160 KHz, and EPC Class Gen-2 uses carrier frequencies of 40 KHz to 640 KHz.

Therefore, in order to process the frequency of the broadband (broadband area) according to the communication protocol standard by a general RFID transmission / reception system in which a signal becomes unstable or an inflow of signals between circuits is easy, a plurality of systems corresponding to each frequency band are provided. Since it must be produced as a single product by the dog, there is a problem that the configuration of the circuit is complicated, the production cost increases and the volume of the product becomes large.

In the present invention, various signals can be processed in accordance with the standard of the RFID communication protocol. Therefore, the hardware configuration of the signal processing stage and the software configuration of the processor / memory are improved, thereby eliminating various signals. Provided is an RFID transceiver system capable of selectively processing.

RFID transmission and reception system according to the present invention includes a phase synchronization circuit for generating a reference frequency signal; A mixer unit receiving the reference frequency signal and generating a frequency signal differentiated according to an RFID protocol standard; And a control unit which transmits a control signal to the phase synchronization circuit so that a reference frequency signal corresponding to the differentiated frequency signal is generated by a frequency hopping method.

In addition, the control unit of the RFID transmission and reception system according to the present invention is two of ISO 18000-6A, ISO 18000-6B, ISO 18000-6C, Electronic Product Code (EPC) Generation-0, EPC Generation-1, EPC Generation-2 The control signal is transmitted to generate a different frequency signal according to the above RFID protocol standard.

In addition, the RFID transmission and reception system according to the present invention further includes a signal separation unit for separating a received signal into an in-phase (I) signal and a quadrature-phase (Q) signal, and the mixer unit predeterminedly divides the I signal and the Q signal. And a first mixer and a second mixer for mixing the I signal and the Q signal with a phase difference of.

In addition, the control unit of the RFID transmission and reception system according to the present invention transmits the control signal so that the frequency signal is generated by the frequency hopping method in the order of the EPC Generation-1, EPC Generation-2, ISO 18000-6 standard. .

In addition, the control unit of the RFID transmission and reception system according to the present invention transmits the control signal so that the frequency band leap with a time period of 0.1 seconds to 0.5 seconds when the differentiated frequency signal is generated.

In addition, the phase synchronization circuit unit, the mixer unit and the control unit of the RFID transmission and reception system according to the present invention is a circuit mounted and interlocked in a mobile communication terminal, the control unit is a movement when the RFID communication start command is transmitted through the interface, After initializing the components for performing communication, the components for performing the RFID communication are initialized and the control signal is transmitted.

Hereinafter, an RFID transmission / reception system according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Prior to the description, the RFID transmission and reception system according to an embodiment of the present invention is an RFID reader, and in particular, an RFID reader functioning in conjunction with a mobile communication terminal such as a PDA (Personal Digital Assistant).

1 is a block diagram schematically showing the overall components of the RFID transmission and reception system 100 according to an embodiment of the present invention.

Referring to FIG. 1, an RFID transceiver system 100 according to an exemplary embodiment of the present invention includes a first antenna 105, a second antenna 110, a reception (Rx) radio frequency (RF) processor 120, and a reception BB ( BaseBand processing unit 130, phase synchronization circuit unit 140, transmission (Tx) RF processing unit 160, transmission BB processing unit 150, control unit 170, interface circuit 180, memory 175 and button unit ( 185).

Currently, RFID communication protocols are classified into ISO 18000-6A, ISO 18006-6B, ISO 18000-6C, Electronic Product Code (EPC) Generation-0, EPC Generation-1, EPC Generation-2, and the like. Signal specifications are different.

2 and 3 is a data table comparing the specifications of the communication protocol applicable to the RFID transmission and reception system 100 according to an embodiment of the present invention, Figure 2 is a standard when a signal is sent from the RFID reader to the RFID tag 3 is a standard when a signal is transmitted from an RFID tag to an RFID reader.

In Figs. 2 and 3, particularly noteworthy is the "Data rate" item. Looking at the data rate item A in Fig. 2, ISO 18000-6A is 33 kHz, ISO 18000-6B is 10 KHz. To 40 KHz, EPC Gen2 uses carrier signals in the 26.7 kHz to 128 KHz band, and when looking at the data rate item (B) in Fig. 3, ISO 18000-6A is 40 KHz, ISO 18000-6B is 40 KHz or 60 KHz and EPC Gen2 use carrier signals in the 640 kHz band.

As such, in order to identify available frequency bands or to minimize the effects of interference between adjacent bands, a frequency hopping method may be used. A representative hopping method may be frequency-hopping spread spectrum (FHSS). have.

Unlike the Direct Sequence Spread Spectrum (DSSS) method, which operates at 12dB SNR using phase shift keying (PSK) phase modulation technology and uses 15 overlapping channels, the FHSS method uses 23 independent channels and spans all channels. It randomly leaps channels by "Random Hopping Sequence" and transmits and receives data.

However, such a conventional hopping scheme is difficult to use for processing signals according to the protocol standard to be solved by the present invention.

In particular, if the leap channel is used by another RFID reader, it is difficult to completely eliminate the inter-reader interference because a frequency collision occurs.

4 is a flowchart illustrating an operation process of the RFID transmission and reception system 100 according to an embodiment of the present invention.

In the following, the components of the RFID transmission and reception system 100 according to an embodiment of the present invention will be described with reference to FIG. 4.

When the user carries the RFID transmission and reception system 100 according to an embodiment of the present invention and grasps the product information (for example, at a loading place such as a warehouse), the user may have a first antenna 105 and a second antenna 110. To the product side, and the button unit 185 can be operated to transmit the information request signal to the corresponding RFID tag (S105).

The button unit 185 transfers the driving signal to the interface circuit 180, and the interface circuit 180 converts the driving signal into a digital signal and transmits the digital signal to the controller 170.

For reference, the interface circuit 180 converts the data (for example, tag information or received intensity indication information, etc.) transmitted from the control unit 170 into a display format in a predetermined format to configure the screen data so that the user can obtain the product information or the RFID. You can check the reception status of the signal.

In the embodiment of the present invention, the control unit 170 is a processor for simultaneously controlling the component providing the function of the RFID reader and the component providing the function of the PDA, when the drive signal converted into a digital signal is delivered, In addition, the memory 175 is initialized, and the frequency hopping program according to the present invention is loaded and executed from the memory 175 (S110).

The controller 170 initializes the circuit elements constituting the reception RF processing unit 120, the reception BB processing unit 130, the phase synchronization circuit unit 140, the transmission RF processing unit 160, and the transmission BB processing unit 150. (S115).

Subsequently, the control unit 170 generates an information request signal (as a digital signal) and transmits it to the transmission BB processing unit 150, and the transmission BB processing unit 150 converts it into a baseband transmission signal after DA conversion processing. Filter / amplify.

The transmission BB processing unit 150 receives the reference frequency signal from the phase synchronization circuit unit 140 and mixes the amplified baseband transmission signal to generate an RF transmission signal.

When the RF transmission signal is generated, the transmission RF processing unit 160 filters / amplifies it and transmits it through the second antenna 110.

The transmission RF processing unit 160 and the transmission BB processing unit 150 will be described in more detail with reference to FIG. 7.

In this way, when the information request signal is transmitted, the control unit 170 sets the priority of different signals according to the protocol standard, and stays in the standby state until the signal is received from the RFID tag (S120).

When the signal is received through the first antenna 105 in the standby state, the reception RF processing unit 120 filters / amplifies the received reception signal as an RF signal, and the reception BB processing unit 130 performs the phase synchronization circuit unit 140. The baseband received signal is generated by receiving a reference frequency signal from the base and mixing the received RF signal with the RF signal.

Here, the process of transferring the reference frequency signal to the receiving BB processor 130 by the phase synchronization circuit 140 is as follows.

In the embodiment of the present invention, the first signal corresponding to the EPC GEN-1 standard, the second signal corresponding to the EPC GEN-2 standard, and the third signal corresponding to the ISO 18000 standard in turn (frequency hopping) (S125), hereinafter, referred to as "first signal", "second signal", "third signal" for convenience of explanation.

The control unit 170 transmits a first control signal to the phase synchronization circuit unit 140 to provide a reference frequency signal corresponding to the first signal, and the phase synchronization circuit unit 140 receives the first reference frequency signal. Transfer to 130 to generate a first signal.

When the control unit 170 analyzes the first signal and the mutual protocol standard is confirmed (YES in S130), the control unit 170 transmits the first control signal so that the first reference frequency signal is continuously supplied (S145), and the analysis result protocol standard. If it is determined that they are different from each other, and transmits a second control signal to the phase synchronization circuit unit 140 to provide a reference frequency signal corresponding to the second signal (No in S130).

The phase synchronization circuit 140 receiving the second control signal transmits the second reference frequency signal to the reception BB processing unit 130, and the reception BB processing unit 130 generates the second signal.

If the control unit 170 analyzes the second signal and the mutual protocol standard is confirmed (YES in S135), the control unit 170 transmits the second control signal so that the second reference frequency signal is continuously supplied (S145), and the analysis result protocol standard. If it is determined that they are different from each other, and transmits the third control signal to the phase synchronization circuit unit 140 to provide a reference frequency signal corresponding to the third signal (NO in S135).

The phase synchronization circuit 140 receiving the third control signal transmits the third reference frequency signal to the reception BB processing unit 130 and the reception BB processing unit 130 generates the third signal.

When the control unit 170 analyzes the third signal and the mutual protocol standard is confirmed (YES in S140), the control unit 170 transmits the third control signal so that the third reference frequency signal is continuously supplied (S145), and the analysis result protocol standard. If it is determined that they are different from each other, the first control signal is transmitted to the phase synchronization circuit unit 140 (NO in S140).

Therefore, the aforementioned frequency hopping process is repeatedly performed until the corresponding frequency signal is found.

Here, in the frequency hopping of the first signal, the second signal, and the third signal, the control unit 170 preferably transmits control signals such that the frequency band hops with a time period of 0.4 seconds.

5 is a block diagram schematically illustrating the components of the phase synchronization circuit unit 140 included in the RFID transceiver system 100 according to an exemplary embodiment of the present invention.

Referring to FIG. 5, the phase synchronization circuit unit 140 includes a TCXO (Temperature Compensated X-tal Oscillator) 141, a first divider 142, a frequency detector 143, a charge pump 144, and a loop. The filter 145 includes a voltage controlled oscillator (VCO) 146 and a second divider 147.

The TCXO 141 is a circuit having a crystal oscillator and controlling the frequency disturbance according to the temperature change. The TCXO 141 provides the oscillation frequency signal having a constant frequency to the temperature changer to the first divider 142.

The first divider 142 receives the first control signal, the second control signal, and the third control signal from the control unit 170, and accordingly reduces the oscillation frequency signal by a predetermined ratio from the phase synchronization circuit unit 140. It is possible to move the band of the final reference frequency signal output to the first reference frequency signal, the second reference frequency signal or the third reference frequency signal.

Through this configuration, the receiving BB processing unit 130 or the transmitting BB processing unit 150 can provide a reference frequency signal required for mixing signals according to the type of communication protocol.

The frequency detector 143 detects a reference frequency signal output from the VCO 146 and compares it with an oscillation frequency signal transmitted from the TCXO 141.

In general, the reference frequency signal is a high frequency (eg, frequency signal in "㎓") signal, and the oscillation frequency signal is a relatively low frequency signal (eg, frequency signal in "MHz" unit) compared to the reference frequency signal.

Accordingly, the second divider 147 converts the reference frequency signal to a relatively low frequency in order to convert the reference frequency signal output from the VCO 146 into a size comparable with the oscillation frequency signal.

The frequency detector 143 compares the frequency of the oscillation frequency signal and the converted reference frequency signal, and transfers a control signal corresponding to the frequency difference to the charge pump 144, and the charge pump 144 supplies a current value according to the control signal. Adjust

The charge pump 144 is an electronic circuit that supplies or absorbs a specific amount of charge according to a control signal. When the voltage of the reference frequency signal is larger than the oscillation frequency signal, the charge pump 144 transfers a specific amount of charge by the branch circuit loop 145. If the voltage of the reference frequency signal is smaller than the oscillation frequency signal, the branch circuit draws a certain amount of charge from the loop filter 145.

The VCO 146 includes a resonator, a power supply (not shown), and the like, and resonates a reference frequency signal without shaking in accordance with a control signal passed through the loop filter 145.

FIG. 6 is a block diagram schematically illustrating a configuration and a connection relationship between a reception RF processor 120 and a reception BB processor 130 included in an RFID transceiver system 100 according to an exemplary embodiment of the present invention.

Referring to FIG. 6, the reception RF processor 120 includes a first band pass filter (BPF) 122 and a low noise amplifier (LNA) 124. The balun circuit 131, the first mixer 132, the second mixer 133, the first low pass filter (LPF) 134, and the second low pass filter 135 are provided. And a first baseband amplifier (136) 136 and a second base station 137.

The first band pass filter 122 (generally provided as a saw filter) filters only the received signal of the corresponding RFID band among the signals received through the first antenna 105.

The low noise amplifier 124 amplifies the filtered received signal when the power of the signal is lowered due to the attenuation and the influence of noise. At this time, since the received signal includes external noise, the noise component is suppressed as much as possible so that the received signal is reduced. Is amplified.

In other words, an important part of determining the noise figure of the communication system is the noise figure of the early block of the system because the overall noise figure is greatly improved when the early block has a small noise figure and a large gain. Therefore, the low noise amplifier 124 is designed by grabbing the operating point and the matching point so that the noise figure has a small value.

The balun circuit 131 separates the RF reception signal transmitted from the low noise amplifier 124 into an I signal and a Q signal. Here, the term "balun" refers to a circuit for converting a balanced signal into an unbalanced signal (or vice versa) as "Balance-Unbalance".

The balun circuit 131 has an output terminal connected to the first mixer 132 and the second mixer 133, respectively. When there is an I signal and a Q signal using the same transmission band, one side is made GND and the other side is a signal. By driving (which is a kind of signal conversion), I or Q signals are separated.

The balun circuit 131 may be implemented through a line combination, a lumped element, a resonant waveguide method, or the like.

The first mixer 132 and the second mixer 133 receive a reference frequency signal from the phase synchronization circuit unit 140, synthesize the separated RF I received signal and the RF Q received signal, and synthesize the I BB (BaseBand). ) Generated with received signal and Q BB received signal.

The I BB received signal and the Q BB received signal are respectively passed through the first low pass filter 134 and the second low pass filter 135 to remove the noise components mixed in the mixing process, and the first BA 136 and The intermediate frequency is amplified through the second BA 137 and transferred to the controller 170.

7 is a block diagram schematically illustrating the components of the transmitting RF processor 160 and the transmitting BB processor 150 included in the RFID transceiver system 100 according to an exemplary embodiment of the present invention.

Referring to FIG. 7, the transmission RF processor 160 may include a power amplifier (PA) 164, an intermediate amplifier (IA) 163, and a voltage gain amplifier (PA) 164 connected to the second antenna 110. And a voltage gain amplifier (VGA) 162 and a second band pass filter 161. The transmission BB processing unit 150 includes a synthesizer 157, a third mixer 155, a fourth mixer 156, and a third mixer. A 1BB filter 153, a second BB filter 154, a first digital to analog converter (DA) 151, and a second DA 152 are included.

When the controller 170 processes a digital signal such as an information request signal, the I (In-phase) signal and the Q (Quadrature-phase) signal, which are digital signal states, are transmitted through the first DA 151 and the second DA 152. Each of the first BB filter 153 and the second BB filter 154 is converted into an analog signal and filters the signal of the noise component introduced on the I BB transmission signal and the Q BB transmission signal during the conversion process.

The third mixer 155 and the fourth mixer 156 receive a reference frequency signal whose power is adjusted to a predetermined size from the phase synchronization circuit 140, and convert the I BB transmission signal and the Q BB transmission signal into a reference frequency signal. Mixing is performed to convert the RF I transmission signal and the RF Q transmission signal, respectively.

In addition, the synthesizer 157 combines the RF I transmission signal and the RF Q transmission signal to generate one RF signal, and the RF transmission signal undergoes an amplification process through a second band pass filter 161.

The voltage gain amplifier 162 amplifies the RF transmission signal by adjusting the gain by a control voltage. Through this function, the gain is automatically controlled according to the electric field strength of the high frequency input signal applied to the antenna terminal. The output of is kept constant.

The voltage-gain-amplified RF transmission signal is sequentially amplified on the intermediate amplifier 163 and the power amplifier 164 and finally amplified into a signal of a size that can be transmitted through the antenna.

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 transmission and reception system according to the present invention, through the software improvement, it is possible to selectively process a signal to be differentiated according to the communication protocol type on one system, simplifying the circuit configuration, and can reduce the production cost.

In addition, according to the present invention, not only an RFID reader as a single product but also an RFID reader product interworking with a mobile communication terminal, a system for selectively processing different signals according to protocol types can be easily implemented in software. There is an effect that can satisfy the desire of consumers to purchase a single product to use a variety of protocol communication services.

Claims (6)

A phase synchronization circuit unit generating a reference frequency signal; A mixer unit receiving the reference frequency signal and generating a frequency signal differentiated according to an RFID protocol standard; And And a control unit for transmitting a control signal to the phase synchronization circuit so that a reference frequency signal corresponding to the differentiated frequency signal is generated by a frequency hopping method. The method of claim 1, wherein the control unit In order to generate different frequency signals according to two or more RFID protocol standards among ISO 18000-6A, ISO 18000-6B, ISO 18000-6C, Electronic Product Code (EPC) Generation-0, EPC Generation-1, and EPC Generation-2, RFID transmission and reception system, characterized in that for transmitting a control signal. The method of claim 1, A signal separation unit for separating the received signal into I (In-phase) signal and Q (Quadrature-phase) signal is further provided, And the mixer unit comprises a first mixer and a second mixer for mixing the I signal and the Q signal with a predetermined phase difference and mixing the I signal and the Q signal, respectively. The method of claim 2, wherein the control unit And transmitting the control signal such that the frequency signal is generated by the frequency hopping method in the order of the EPC Generation-1, EPC Generation-2, and ISO 18000-6 standards. The method of claim 1, wherein the control unit In the generation of the differentiated frequency signal, RFID transmission and reception system, characterized in that for transmitting the control signal so that the frequency band leap with a time period of 0.1 seconds to 0.5 seconds. The method of claim 1, The phase synchronization circuit unit, the mixer unit and the control unit are circuits mounted on the mobile communication terminal and interlocked, When the control unit initiates an RFID communication start command through an interface, the controller initializes the components for performing the mobile communication, initializes the components for performing the RFID communication, and transmits the control signal. Transceiver system.

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