KR101416991B1 - Radio Frequency IDentification traceiver system - Google Patents

Abstract

The RFID transceiver system according to the present invention includes a receiving mixer unit for processing a received signal as a baseband signal; A transmission mixer unit for processing a transmission signal into an RF signal; A phase synchronization circuit unit for supplying an oscillation frequency signal to the reception mixer unit and the transmission mixer unit; Analyzing the baseband received signal to identify an RFID channel used in another system, generating interference channel information to form a transmission signal, and controlling the phase synchronization unit to process frequency hopping.

According to the present invention, since the frequency hopping can be processed by grasping the frequency channel used by another system and avoiding the channel in which the interference is generated, it is possible to reliably restore / process the received signal and perform communication without interference between communication systems And it is possible to supply a large amount of energy with a tag. Also, since the channel information in which the interference occurs can be shared between the RFID transmission / reception systems, it is possible to accurately grasp the channel in which the interference occurs, and it is possible to save hardware resources and operator resources.

Description

[0001] The present invention relates to an RFID (Radio Frequency Identification)

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

FIG. 2 is a diagram illustrating a form in which an RFID transceiving system according to an embodiment of the present invention forms a reader network.

FIG. 3 is a diagram schematically illustrating an RFID signal standard used in the RFID transmission / reception system according to the embodiment of the present invention.

FIG. 4 is an enlarged diagram of a section in which command data is loaded among the RFID signal standards used in the RFID transmission / reception system according to the embodiment of the present invention.

Description of the Related Art

100: RFID transmission / reception system 105, 110: reception antenna, transmission antenna

122: LNA 124, 210: first / second band-pass filter

130: balun circuit 142, 144: first mixer, second mixer

152, 154: first LPF, second LPF 155:

160: Control section 162: Data analysis section

164: interference information generator 166: hopping channel manager

168: data constructing units 182 and 184: first IF filter, second IF filter

192, 196: third mixer, fourth mixer 220: PA

The present invention relates to an RFID transmission / reception system capable of avoiding inter-frequency channel interference.

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.

On the other hand, the RFID system is generally implemented through envelope detection using an ASK (Amplitude Shift Keying) modulation method. According to the conventional design method, the bit error rate is lowered and the data recognition rate is low.

Particularly, in the case of an RFID reader, since a tag is moved at a high speed, a change in the radio wave environment is significant and a change in the received signal is largely changed according to an external environment change (for example, Phase change, etc.), especially the frequency interference between RFID readers, greatly affects 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.

Also, when the tag is moved, the supply position of the energy also changes, which degrades the recognition rate and deteriorates the reception sensitivity and the recognition distance.

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 entire frequency bandwidth is narrow and the number of carriers is small, the frequency of the 900 MHz band can be perceived as a problem that the influence of an external interference signal including a transmission signal or a phenomenon of interference between the tag signals is more fatal.

The present invention provides an RFID transmission / reception system that stably communicates by recognizing a channel used by another system and processing a frequency hopping by avoiding an interference channel.

In addition, the present invention provides an RFID transmission / reception system capable of constructing a multi-system by sharing channel information in which interference occurs.

The RFID transceiver system according to the present invention includes a receiving mixer unit for processing a received signal as a baseband signal; A transmission mixer unit for processing a transmission signal into an RF signal; A phase synchronization circuit unit for supplying an oscillation frequency signal to the reception mixer unit and the transmission mixer unit; Analyzing the baseband received signal to identify an RFID channel used in another system, generating interference channel information to form a transmission signal, and controlling the phase synchronization unit to process frequency hopping.

Hereinafter, an RFID transmitting / receiving system according to the present invention will be described in detail with reference to the accompanying drawings. In an embodiment of the present invention, the RFID transmitting / receiving system is an RFID reader using a UHF band carrier signal.

1 is a block diagram schematically showing the components of an RFID transmitting / receiving system (hereinafter referred to as "reader according to the present invention " as needed) 100 according to an embodiment of the present invention.

1, a reader 100 according to the present invention includes a reception antenna 105, an LNA (Low Noise Amplifier) 122, a first band pass filter 124, a balun circuit 130, a reception mixer 142 A first local oscillator 144, a first LPF 152, a second LPF 154, a demodulator (hereinafter, referred to as " first mixer 142 " A first IF filter 182, a second IF filter 184 and transmission mixer units 192 and 196 (hereinafter referred to as a "third mixer 192 "), a control unit 160, a phase synchronization circuit unit 200, Second mixer 196, second local oscillator 194, synthesizer 198, second bandpass filter 210, power amplifier 220 and transmit antenna 110 The control unit 160 includes a data analyzing unit 162, an interference information generating unit 164, a hopping channel managing unit 166, and a data generating unit 168.

The receiving antenna 105 receives a signal from a tag or another reader. The reader 100 according to the present invention generates channel interference information by analyzing signals of other readers and shares channel interference information with other readers The following description will be made assuming that the received signal is a signal from another reader.

The LNA (Low Noise Amplifier) 122 low-noise amplifies the received signal, and the first band-pass filter 124 filters signals of spurious components mixed in the amplification process.

The balun circuit 130 separates the input signal into an I signal and a Q signal having a phase difference of 180 degrees. The output terminal of the balun circuit 130 is connected to the first mixer 142 and the second mixer 146, , And drives the signal to the other side (a kind of signal conversion) to separate the I signal or the Q signal.

The first mixer 142 and the second mixer 146 receive the oscillation frequency signal from the first local oscillator 144 and synthesize the separated I signal and Q signal to generate a baseband signal.

The phase locked loop circuit 200 generates a phase synchronization signal so that the oscillation frequency signal does not flow and is stably supplied to the first local oscillation circuit 144 and the second local oscillation circuit 194.

The I signal and the Q signal generated as the baseband signal pass through the first LPF (Low Pass Filter) 152 and the second LPF 154, respectively, and noise components mixed in the mixing process are removed.

The demodulating unit 155 includes an analog to digital converter (ADC), demodulates the baseband signal into a digital signal, and transmits the demodulated signal to the controller 160.

The controller 160 controls the wireless communication with the RFID tag with a communication protocol and transmits an information request signal periodically to grasp the position of the RFID tag.

In addition, the controller 160 analyzes the code of the tag identification information received from the RFID tag, and at this time, converts the data format and processes filtering to extract necessary information.

The control unit 160 includes a data analyzing unit 162, an interference information generating unit 164, a hopping channel managing unit 166 and a data generating unit 168. Each of the configuring units includes a field programmable gate array ) Circuit or a DSP (Digital Signal Processing) circuit.

The data analyzer 162 constructs a demodulated received signal as a digital signal standard that can be analyzed. The interference information generator 164 analyzes the digital signal and selects a frequency band of the received signal.

For example, the data analyzing unit 162 can distinguish between a data interval and an energy transmission interval (which is an energy signal transmitted by a tag) The specifications will be described in detail with reference to Figs. 3 and 4).

In addition, the interference information generating unit 164 can detect whether or not an interference phenomenon occurs in the received signal by detecting the power level of the received signal.

In this manner, the frequency channel information of the received signal is generated as interference channel information. The interference information generating unit 164 shares the interference channel information with other readers and processes the information as network information.

That is, when the interference signal generated by the other reader is included in the received signal as a result of analyzing the received signal, the interference information generator 164 extracts the interference signal and stores / manages the interference channel information together with the generated interference channel information Interference channel information generated by the interference information generating unit 164 itself, and interference channel information transmitted from another reader are collectively referred to as "interference channel information").

The hopping channel manager 166 sets a hopping start channel according to the interference channel information (generates hopping start channel information), adjusts a hopping cycle (generates hopping cycle information) And generates channel synchronization information for processing hopping.

The hopping channel management unit 166 transmits a control signal to the phase synchronization circuit unit 200 as hopping start channel information, hopping cycle information, and channel synchronization information are generated. The hopping channel management unit 166 transmits the control signal to the phase synchronization unit 200, .

Therefore, the first local oscillation circuit 144 and the second local oscillation circuit 194 can differentiate and supply the oscillation frequency signal, and the transmission / reception signal can be demodulated or modulated using the hopped frequency channel signal.

The reader 100 according to the present invention can not only control the frequency hopping operation by avoiding the frequency channel used in the other reader but also apply the anti-collision method on one channel. The data configuration unit 168 performs this function.

The data configuration unit 168 may include a device identification number, a hopping channel number (information on channels currently being used by other readers including itself), hopping start channel information, hopping cycle information, and channel synchronization information And carries the interference channel information included in the carrier signal to constitute a transmission signal.

The transmission signal may include tag information, of course, the carrier signal may be a signal of a hopped frequency channel, and a signal to be transmitted to a tag or a signal to be transmitted to another reader may be configured.

On the other hand, when the hopping is not processed and the channel used by the other reader is used as a carrier signal, the data configuration unit 168 stores the channel in which the energy signal of the channel used by the other system is stored, The collision avoidance method can be applied by disposing them on the carrier signal.

The first IF filter 182 and the second IF filter 184 filter the I transmission signal and the Q transmission signal, which are digital signal states, respectively, to remove noise components, and then transmit the filtered I transmission signal and the Q transmission signal to a third mixer (192) and the fourth mixer (196).

The third mixer 192 and the fourth mixer 196 mix the oscillation frequency signal transmitted from the second local oscillation circuit 194 with the I transmission signal and the Q transmission signal respectively and transmit the RF I transmission signal and the RF Q transmission And the RF I transmission signal and the RF Q transmission signal are combined into a single RF transmission signal through a combiner 198.

The second band-pass filter (BPF) 210 removes mixed spurious component signals in the frequency synthesis process, and the PA 220 amplifies the filtered RF transmission signal to a transmittable power level, (110).

FIG. 2 is a diagram illustrating a form in which the RFID transceiving system 100 forms a reader network according to an embodiment of the present invention.

As described above, as the transmission signal including the interference channel information is constructed and transmitted, the plurality of the readers 100 can share the interference channel information and process the shared interference channel information as the network information.

Referring to FIG. 2, adjacent readers 100 share one another's interference channel information in a group L1, one of the readers 100 serves as a bridge, By sharing the interference channel information again with the reader 100 having the group L2, the readers of the entire area can share information on the currently used channel and can stably communicate with the tag 300 .

FIG. 3 is a diagram schematically illustrating an RFID signal standard used in the RFID transmission / reception system 100 according to the embodiment of the present invention. FIG. 4 is a diagram illustrating a RFID signal format used in the RFID transmission / reception system 100 according to the embodiment of the present invention. FIG. 5 is a diagram showing an enlarged section of the signal specification in which command data is loaded. FIG.

In FIG. 3, a section " A "is a preamble section for notifying the start of a signal and defining a type and a standard of a signal, and a section" B " Information ").

The intermission channel information, i.e., the reader identification number, the hopping channel number, the hopping start channel information, the hopping cycle information, the channel synchronization information, and the like are loaded in the section "C" do.

The "D" section is the section where the response bit of the tag or other reader is loaded, and the "E" section is the energy signal section.

For example, if another reader uses the channel signal of the standard shown in FIG. 3 as a carrier signal, the data construction unit 168 transmits the transmission signal, i.e., the "A" Can be synchronized with the energy signal interval (E).

Therefore, by using the frequency collision avoiding technique, a plurality of readers can perform communication through one channel.

Referring to FIG. 4, it can be seen that the "C" section is enlarged. The section " C1 "is the preamble signal section of the data area and the section" C2 "

The section "C3" is a signal section for identifying the data area, and the section "C4 "

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 RFID transmission / reception system of the present invention, frequency hopping can be processed by grasping a frequency channel used by another system and avoiding an interference channel, thereby restoring / processing the received signal stably, Communication can be performed without interference, and it is possible to supply a large amount of energy with the tag.

In addition, according to the present invention, channel information in which interference occurs can be shared between RFID transmission / reception systems, so that it is possible to accurately grasp a channel in which interference occurs and to save hardware resources and operator resources.

In addition, according to the present invention, since a multi-system can be constructed even when the same channel or adjacent channel is used, the degree of freedom of arrangement of the system is secured and it is not necessary to provide a complicated control system for controlling a plurality of communication systems It is effective.

Claims (9)

A receiving mixer unit for processing a received signal transmitted from the reader as a baseband signal; A transmission mixer unit for processing a transmission signal into an RF signal; A phase synchronization circuit unit for supplying an oscillation frequency signal to the reception mixer unit and the transmission mixer unit; And a controller for analyzing the baseband signal to identify an RFID channel used in another system and controlling the phase synchronization unit to adjust a phase synchronization signal based on the hopping information generated from the received signal, . The method according to claim 1, Wherein the phase synchronization circuit unit adjusts a band of the oscillation frequency signal, Wherein the reception mixer unit and the transmission mixer unit process a channel-hopped signal using the band-adjusted oscillation frequency signal. The apparatus of claim 1, wherein the control unit And the interference channel information composed of the transmission signal is shared with the other system and processed as network information. 4. The method of claim 3, wherein the transmission signal including the interference channel information comprises: A device identification number, and a hopping channel number. The apparatus of claim 1, wherein the control unit And generates the transmission signal by shifting the energy signal section and the data section of the channel used by the other system. The apparatus of claim 1, wherein the control unit And generates a transmission signal by separating a transmission signal to be transmitted to the other system and a transmission signal to be transmitted to the tag. The receiver of claim 1, wherein the receiving mixer unit, the transmission mixer unit, the phase synchronization circuit unit, An RFID transceiver system included in an RFID reader. delete 5. The apparatus of claim 4, wherein the control unit A data analyzer for analyzing the baseband signal; An interference information generating unit for generating the interference channel information and processing the generated interference channel information with network information by sharing with the other system; A hopping channel manager for generating the hopping information according to the interference channel information; And And a data constructing unit configured to construct a transmission signal including the interference channel information, the device identification number, and the hopping channel number, and to construct a transmission signal by shifting an energy signal interval and a data interval of a channel used by the other system, The hopping information includes: Hopping start channel information, hopping cycle information, and channel synchronization information.

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