WO2008013396A1

WO2008013396A1 - Extensive rfid system for reader-tag communication and method thereof

Info

Publication number: WO2008013396A1
Application number: PCT/KR2007/003560
Authority: WO
Inventors: Jun Suk Park; Ha Ryoung Oh; Jae Cheol Shin; Jung Suk Lee; Hak Yong Lee
Original assignee: C & S Microwave Co., Ltd
Priority date: 2006-07-25
Filing date: 2007-07-25
Publication date: 2008-01-31
Also published as: KR20080009820A; KR100801904B1

Abstract

The present invention relates to a RFID system for reading or writing information of RFID tag using wireless data communication. The extensive RFID system for reader-tag communication according to the present invention comprises a wireless communication device(RF shower system) which include a communication means for arranging an order of communication for the readers when a plurality of readers exist in the reader zone without happening any confliction between the readers, so that communication could be performed smoothly between the plurality of readers and tags. The extensive reader-tag RFID system according to the present invention, has advantages in that confliction problem, which may be happened when a plurality of readers exist in same region, could be solved and in that reading and writing distance between readers and tags could be considerably extended by comprising a mean for amplifying a weak signal from a low- powered reader to high-powered signal through communication with the reader to extend distance of reading and writing information between reader and tags, and for transmitting the high-powered signal to the tags.

Description

EXTENSIVE RFID SYSTEM FOR READER-TAG COMMUNICATION AND METHOD THEREOF

Technical Field

[1] The present invention relates to a RFID system for reading or writing an information of RFID tag using wireless data communication, and more particularly, to an extensive RFID system for reader-tag communication having a means for amplifying a weak signal from low-powered reader exist in a certain area(reader zone), forwarding the amplified signal to a plurality of passive-type tags, and let the reader read an acknowledge signal(thus, information data) sent by the tag, so that distance of reading and writing between a reader and a tag could be enlarged, as in an intercommunication which read and/or write any information from and/or to a plurality of passive-type tags in which does not have any battery, and having a wireless communication device include a communication means for arranging an order of communication for the readers when a plurality of readers exist in the reader zone without happening any confliction between the readers, so that communication could be performed smoothly between the plurality of readers and tags. Background Art

[2] In general, Radio Frequency Identification is a kind of technology which can be used for recognizing, tracing, and controlling things which tags are attached or an animal/human by reading and writing unique identification information. The RFID system includes a plurality of tags or transponders attached to a thing having unique identification information, an animal, or a human being and RFID reader or interrogator.

[3] FIG. 1 shows a general construction of RFID system of a conventional art.

Referring to FIG. 1, RFID tag 20 is comprised of an antenna and an IC chip, wherein the IC chip is comprised of built-in RF circuit for handling RF signal, a control logic, memories, and the likes. The RFID reader send query signal of a certain frequency range to tag 20, the tag receives acknowledge signal Fl during backscatter modulation. Meanwhile, the RFID reader 10 could be connected a network 40, such as computer(s), the network do a function of storing and analyzing an information which read by RFID reader or written in the tag using a predetermined application program.

[4] FIG. 2 shows a basic operation of the conventional RFID system. Referring to FIG.

2, a tag 20 is a passive type of tag which does not built-in any battery. Thus, for communication between the reader 10 and tag 20, the passive type of tag should be activated. For this, the reader 19 transmits a wireless power together with a pre- determined query signal. Then the passive type of tag 20 is activated using the wireless power, and send a unique identification information therein to the reader 10. Such as this, in the conventional RFID system, a communication and transmittance of power happen at the same time.

[5] In general, there are two kinds of methods that the reader provides power using wireless. The one of method uses a multi-winding coil between the reader and tag(s). The other method uses electro-magnetic waves of high frequency ranges between reader and tag(s).

[6] Magnetic field combination method using the multi- winding coil could be operated only in a short distance for recognizing of tag, therefore it could be used for limited purpose, such as for an entrance management and a pass card. Recently, the RF bandwidth communication method of which the recognition distance could be extended to over 10 meters, is widely used. In this RF bandwidth communication method, the distance of communication between the tag and the reader could be enlarged by increasing the power of communication signal output. However, as the transmitting output of the reader increases, the frequency interference increases between neighboring readers or between wireless communication devices using same or similar ranges of frequency. Further, for radiating communication signal with high power, the size of reader will get bigger and the battery consumption will increases, and the production price will goes up. These problems stand in the way of installing a RFID reader in a personal communication terminal.

[7] Also, the passive type of tag in the conventional RFID system only functions of reflecting identification code and information, so that the tag will be activated only when itself communicate with the RFID reader. However, recent RFID system has a processor and a memory so as to can write data therein as well as a readable data therefrom. Therefore, it requires an active tag which could be activated in continue. However, battery built-in active tag has disadvantage in that it is a high price of device, and also difficult to be miniaturization, and in that it has limited operation time according to lifetime of battery. Thus, a lot of demand for the passive type of tag, which could be activated continuously without battery built-in so that it is easy to be miniaturization and to make it with low-price, is expected.

[8] Meanwhile, in the era of Ubiquitous Sensor Network(USN), it is expected that, a microminiaturized tag is attached to an automobile, an animal, and even a human being as well as wall of building, a ground and a footway of the street, and reader which reads an information from tags is installed in many places, or the tag information is collected in real-time base by user's carrying of a reader and the tag information could be transmitted through network.

[9] Therefore, the tag which can be used for USN is requested a function of sensing cir- cumference environmental information, such as temperature, humidity, pollution information, and crack information, and forwarding to network actively by adding sensing and memory function as well as a function of forwarding identification information as in a conventional technical field. To construct Ubiquitous Sensor Network, the development of low-priced, high-functional, and microminiaturized tag is requested.

[10] The tag suitable to USN should be a low-priced and microminiaturized one so that it could be installed lot of places, as well as be the one combined of sensing function so that lot of information could be stored and proceed. Therefore, as for the final aim, the low priced tag can perform these functions without a hitch. However, in the RFID system of conventional prior art, the passive type of tag receives energy necessary for operation from a reader, so that the same tag could not be activated without reader or when the reader does not operated. Thus, the passive type of tag could not be expected any function of sensing environmental information continuously.

[11] Also, in the conventional tag and reader, the output power for transmitting a signal from the reader to the tag should be increased to secure sufficient recognition distance and to achieve high-end functions. But, as described above, frequency interference increases as the output power increases. Also, to perform continuous sensing by the passive-type tag, both of a reader and a tag should be in close area, so that the portability of reader strongly is subject to be restricted.

[12] To solve this problem, a RFID system for a low-powered reader- tag communication in conventional art, as shown in Fig. 3, a wireless communication device for providing power continuously to the passive type of tag, which radiates high frequency signal of a predetermined frequency range, has been suggested.

[13] Thus, the RFID system for a low-powered reader-tag communication in conventional art is comprised of a RFID reader 10, a passive type of tag 20, and wireless communication device 30. RFID reader 10 sends query signal of F frequency range to the tag 20, and receives response signal of F frequency range from the tag 20. The wireless communication device 30 radiates high frequency signal of a predetermined F or F frequency range, so that provides power to the passive type of tag 20 in the certain area of radiation zone via wireless communication. The passive type of tag 20 is activated using the high frequency signal of a predetermined F or F frequency range radiated from the wireless communication device 30, receives the query signal of F frequency range, and sends response signal of F frequency range in response to the query signal. At this moment, the reader 10 need not to transmit power for responding to the tag 20. Therefore, as RFID reader need not transmit power, the output power of the query signal F could be reduced considerably. The reducing of power for RFID reader 10 just as the above-described is more useful when the same is installed to personal mobile communication terminal. Thus, it is quite important to solve any frequency interference between a plurality of personal mobile communication terminals of which reader installed, and to make them low-powered and miniaturized ones.

Disclosure of Invention

Technical Problem

[14] However, as for the reader- tag communication in RFID system of conventional, the maximum distance to read or write a information of tag 20 could be extended by the power transmission F or F which transmitted from the wireless communication device 30 , but continuous wave(CW) type of power transmitting signal which transmit power only from the wireless communication device deteriorate modulation index which denotes a degree of getting worse in the quality of data, so that the some characteristics is sensitive to the level of power receiving regarding on power transmittance F or F and the position of tag 20. Technical Solution

[15] The present invention provides an extensive RFID system for reader-tag communication having wireless communication device in which zones separated by a reader zone for communication between the RFID reader and the wireless communication device, a tag zone for communication between tags and wireless communication device, and a recognition zone for reading and writing response signal of tags by the RFID reader to get information of the tag located outside of recognition range easily.

[16] Further, the present invention provides an extensive RFID system for reader- tag communication having wireless communication device for adjusting order of reader's communication with respect to tag when a plurality of readers are in a single communication channel to prevent any confliction between readers.

[17]

[18] According to an aspect of the present invention, there is provided an extensive

RFID system for reader-tag communication for performing communications between at least one of RFID reader and passive tag, the RFID system comprising a wireless communication device including a communication means for amplifying a weak signal from a low-powered reader to high-powered signal through communication with the reader to extend distance of reading and writing information between reader and tags, and for transmitting the high-powered signal to the tags.

[19]

[20] Preferably, the wireless communication device is independently installed in a way that it is separated with the RFID reader and forms a certain area of reader zone be able to communicate with at least one of tags for communication with the RFID reader and a certain area of tag zone be able to cover at least one of passive tag by amplifying weak signal of the reader.

[21]

[22] More preferably, said wireless communication device comprises, a signal processor for selecting only desired signal from reader signals and converting the desired signal to a predetermined low-frequency signal, an amplifying/transmitting portion for amplifying the reader signal and transmitting the amplified signal to tags, a communication order arranging portion for arranging an order of communication for a plurality of readers, and sending to the reader, a control portion for performing control function of analyzing and storing reader signal and controlling the signal processor and the amplifying/transmitting portion and the communication order arranging portion, and a memory for storing command information of the reader obtained from wireless communication between at least one of readers.

[23]

[24] Preferably, the wireless communication device comprises a means for communicating with each reader to prevent confliction between readers when a plurality of readers exist so that order of communication through a communication channel between the each reader and tags.

[25]

[26] According to another aspect of the present invention, there is provided a RFID recognition method performed in an extensive RFID system for reader-tag communication for performing communications between at least one of RFID reader and passive tags and wireless communication device, wherein the wireless communication device includes a communication means for amplifying a weak signal from low- powered reader, forwarding the amplified signal to a plurality of passive-type tags, and communicating with each reader to prevent confliction between readers characterized in that comprising:

[27] transmitting communication signal to the wireless communication device for occupying a communication channel by the reader, arranging and deciding final order of communication in response to the communication signal by the wireless communication device, transmitting query signal to the wireless communication device according to the decided communication order by the reader, amplifying query signal from a reader finally decided in order of communication and transmitting the amplified signal to tags in tag zone, activating of the tag by receiving reader's query signal and transmitting a response signal to a reader in recognition zone during backscatter modulation process; and reading or writing tag information using the response signal of the tag by the reader. Advantageous Effects

[28] In a extensive RFID recognition system for reader-tag communication according to the present invention with regard to communication between a plurality of low- powered reader and tags, the confliction problem which rises as most serious problem in RFID system currently, could be solved by deciding order as suggested in this invention when the reader communicates with tags through communications between each reader and the wireless communication device Also, the reader can receive the response signal during backscatter modulation after activating of the passive tag by transmitting amplified high-powered signal, which is amplified signal of weak signal from low-powered portable reader, to the same passive tag. Therefore, the possible distance for reading and writing of tag's information could be extended considerably.

[29] Thus, according to the present invention, it is easy to be low power consumption and miniaturization and to make it with low-price, as recognition distance of reader could be extended without increasing power output of the reader.

[30] Also, the extensive reader-tag RFID system according to the present invention, have advantages in that confliction problem, which may be happened when a plurality of readers exist in same region, could be solved and that reading and writing distance between readers and tags could be extended, so that considerable contribution to commercializing and expanding of service kinds may be expected. Brief Description of the Drawings

[31] FIG. 1 is a schematic diagram which shows a general construction of RFID system of a conventional art.

[32] FIG. 2 is a schematic diagram which shows a basic operation of the conventional

RFID system.

[33] FIG. 3 is a schematic diagram which shows a RFID system for a low-powered reader-tag communication in conventional art.

[34] FIG. 4 is a schematic diagram which shows a basic construction of an extensive

RFID system for reader-tag communication according to the present invention.

[35] FIG. 5 is a schematic diagram which shows detailed construction of wireless communication device in FIG. 4 as for illustration purpose.

[36] FIG. 6 is a schematic diagram which shows a basic construction of an extensive

RFID system for reader-tag communication according to the preferred embodiment of the present invention.

[37] FIG. 7 is a flow chart which shows an operation procedure of an extensive RFID system for reader-tag communication according to the preferred embodiment of the present invention. Best Mode for Carrying Out the Invention [38] The present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown.

[39] FIG. 4 shows a basic construction of an extensive RFID system for reader-tag communication according to the present invention. As shown in FIG. 4, an extensive RFID system for reader-tag communication according to the present invention is comprised of RFID reader 10, passive tag 20, and wireless communication device 200, and forms a reader zone 101 which is being a communication region of reader for communication between a RFID reader and the wireless communication device, a tag zone 102 which is being a communication region for reader signal transmission to the tag and the wireless communication device, and a recognition zone 103 which is being a communication region for receiving response signal from tags by RFID reader so that the RFID reader get a backscatter modulated response signal from the tag.

[40] The said a plurality of RFID reader 10 and the wireless communication device 200 arrange an order of communication for the readers when a plurality of readers exist in the reader zone without happening any confliction between the readers. Reader 10 forms a communication region reader zone 101 in which communication the reader 10 can communicate with the wireless communication device 200.

[41] The communication between the reader 10 and the wireless communication device

200 could be performed by allocating an arbitrary communication channel F using a separate protocol as shown in FIG. 4, also could be performed using the channel which is used for communication between the reader 10 and the tag 20 and the extended channel. Thus, this invention will not be limited to using the arbitrary communication channel F .

X

[42] Also, when the reader 10 does not receive any confirmation signal or any other information from the wireless communication device 200, the reader 10 prescribe the communication channel as a RFID system without wireless communication device, then the reader 10 can try to communicate independently with the tag 20 for recognizing the same tag 20. Deciding on whether the wireless communication device exists or not could be performed using the arbitrary communication channel F ., also a

X plurality of the reader 10 transmit Beacon signal to readers continuously so that the reader 10 can find out existence of the wireless communication device 200 by the Beacon signal without communication with the wireless communication device 200. [43] As for the extensive RFID system with wireless communication device 200, each reader 10 transmits a query signal for reading or writing information of passive tag 20 to the wireless communication device 200 according to the order arranged by the wireless communication device 200, the wireless communication device 200 amplify the query signal from the reader 10 and transmit to tag zone 102 arbitrary allocated. At this time, the tag exist in tag zone 102 allocated by the wireless communication device 200 receive the signal of the wireless communication device 200, and therefore the tag itself activated, then tag zone 102, in which can recognize the query signal form the reader 10, is formed. Therefore, the tag 20 recognizes the signal from the wireless communication device 200 as reader signal and then the tag 20 of itself is activated by the received power. Then, the tag 20 recognizes the command of reader 10 and transmits the identification information of itself to reader 10 in the recognition zone 103 during scattered modulation.

[44] The reader 10 receives a response signal from a relatively long distance of area, and reads the unique information of the tag 20 or write an arbitrary information to the tag 20 by a series of communication process. From this, arbitrary information from the reader 10 could be written to the tag 20 via the wireless communication device 200.

[45] As described above, the extensive RFID system according to the present invention amplifies the weak signal from the reader 10 and transmits to the tag 20, so that the distance of writing and reading could be extended as well as any confliction between the readers could be prevented by the communication between the reader and the wireless communication device, which should be noted.

[46] FIG. 5 shows detailed construction of wireless communication device in FIG. 4 as for illustration purpose. As shown in FIG. 5, the wireless communication device 200 includes an antenna 201, a circulator 202, a signal processor 210, an IF divider 240, a transmitter 220, a control portion 250, and a communication order arranging portion 230.

[47] The signal processor 210 is comprised of a first band-limited filter 211, a LNA 212, an attenuator 213, a first frequency converter 214, an amplifier 215, and a SAW filter 216. The communication order arranging portion 230 is comprised of D/A converter 231, IF band-pass filter 232, an amplifier 233, a third frequency converter 234, a band- limited filter 235, an amplifier 236, a third attenuator 237, and high output amplifier 238.

[48] Now the operation of the said wireless communication device 200 will be described.

[49] The antenna 201 is for transmitting and receiving of signals for communication with reader 10. The circulator forwards a reader signal of RF band received from the antenna 201 to the first band-limited filter 211, and forwards a communication channel signal F of RF band to the antenna 201 for transmitting to reader. The first band- limited filter passes reader signal only without conference of other frequency bands. The LNA 212 amplifies the reader signal which is passed from the first band-limited filter 211. The attenuator 213 adjusts the level of the reader signal passed the LNA 212 to a predetermined adequate level. The first frequency converter 214 converts the attenuated signal of adequate level by the attenuator to low-frequency signal. The amplifier 215 amplifies low-frequency signal transmitted from the first frequency converter 214, and passes only IF band within the amplified IF signals.

[50] Then, the second frequency converter 221 do reverse transforms the reader signal received from the IF divider 240 to a signal of RF band originally. The second band- limited filter 222 passes only desired band of signal with regard to the signals received from the second frequency converter 221. The amplifier 223 amplifies the output signal of the second band- limited filter 222. The second attenuator 224 attenuates the level of the amplified signal to a predetermined adequate level, and outputs RF band reader signal. The first high output amplifier 225 amplifies the RF band reader signal from the second attenuator 224 and outputs a reader signal of high output.

[51] Now, the output antenna 203 transmits the signal of high output from the first high output amplifier 225 to the tags. IF divider 240 divides the reader signal of IF frequency which is passed from the SAW filter 216 and transmit to the second frequency converter 221 and A/D converter 218. A/D converter 218 converts analog reader signal of IF frequency band to digital data.

[52] Meanwhile, the control portion 250 performs control function for analyzing and storing the reader signal in digital form received from the A/D converter 218, and encodes arrangement data of FMO and transmits to the reader which has been tried to communicate with.

[53] The D/A converter 231 do reverse transforms the digital arrangement data received from the control portion 250 into an analog arrangement signal. The IF band-pass filter 232 passes only desired band of signal within the signals received from the D/A converter 231. The amplifier 233 amplifies the filtered arrangement signal of IF frequency band. The third frequency converter 234 converts IF arrangement signal into the arrangement signal of RF band. The third band-limited filter 235 passes only a desired band of signal within the signals received from the third frequency converter 234. The amplifier 236 amplifies the output of the third band-limited filter 235. The third attenuator 237 attenuates the level of the amplified signal to a predetermined adequate level. The high output amplifier 238 amplifies the output of the third attenuator 237 to a desired level, and transmits the arrangement signal of RF band to the reader 10 through the circulator 202.

[54] Now the signal flow of communication channel F for the communication order ar- rangement through communication channel F will be described regarding on the

X extended RFID system according to the present invention. First of all, when the reader 10 transmits communication channel signal for channel F X possessing to wireless com- munication device 200, the signal is amplified by LNA 212 through antenna 201, circulator 202, and first band-limited filter 211. [55] The level of amplified signal is adjusted again to a certain adequate level in second attenuator 213. Level controlled signal will be converted into digital signal through the first frequency converter 214, amplifier 215, SAW filter 216, and A/D converter 218.

[56] The control portion 250 make a base-band signal by demodulating received digital signal, then analyze and check sent information from the reader, and decide on whether any confliction happens between the readers in current communication channel.

[57] When it has been decided that any confliction happened between the readers, the control portion 250 transmits NACK signal or no answer signal. In contrast, when is has been decided that any confliction may not happen between the readers, the control portion 250 transmits ACK signal to the reader through D/A converter 231.

[58] According to the above described preferred embodiment of the present invention, the method, of transmitting NACK signal, no answer signal, or ACK signal for sending communication channel F signal as a result of deciding on whether any confliction happened between the readers by the controller, has been used, however, this method is only for exemplary purpose as the skilled in the art will recognize, and thus the scope of the present invention will not be limited to this specific embodiments, and other modified method may be used.

[59] When the arrangement of communication order completed through the communication channel F between a plurality of readers 10 and wireless communication device 200, a communication will now be allocated between the reader 10 and tag 20. Then the reader transmits a query signal for trying to read or write information of the tag, and the wireless communication device 200 receives the query signal of the reader through antenna 201. The said query signal goes through circulator 202, first band- limited filter 211, LNA 212, and first attenuator 213, and is converted into IF frequency in the first frequency converter 214, and an only desired frequency band will be passed through amplifier 215 and SAW filter 216. Passed signal is converted into a reader query signal of RF band in second frequency converter 221 through IF divider 240. The converted reader query signal of RF band will go through second band- limited filter 222 and amplifier 223, so that the level of itself is attenuated to a predetermined adequate level. The attenuated signal will now be radiated to the tags in the already allocated tag area through first high-output amplifier 225, output antenna 203.

[60] The tag 20 which received reader signal from the wireless communication device

200, transmits its unique information to the reader in the recognition zone during scattered modulation, and the reader 10 can read or write information of tag located at which is relatively long distance. Thus, according to the present invention, a wireless communication device 200 is added to a RFID system of which low-powered readers 10 are used inevitably, so that an extensive RFID system has been constructed, and also the extensive RFID system has an advantage in that the recognition and writing distance may be considerably extended. [61] FIG. 6 shows a basic construction of an extensive RFID system for reader- tag communication according to the preferred embodiment of the present invention. As shown in FIG. 6, a plurality of readers 10 may be existed in the reader zone 101 between the reader 10 and the wireless communication device 200, adjusting process will be go through between each of readers 10 and the wireless communication device 200 to communicate with the reader 10. Then, because that the wireless communication device 200 can form a plurality of tag zone 102 through a plurality of antenna, the reader 10 can communicate with a tag 20 in tag zone 102 through the wireless communication device 200.

[62] Further, FIG. 7 shows an operation procedure of an extensive RFID system for reader-tag communication according to the preferred embodiment of the present invention. As shown in FIG. 7, the reader 10 transmits a communication signal for channel possession to the wireless communication device 200 to communicate with the tag 20(301 of FIG. 7). The wireless communication device 200 starts to decide on confliction possibility between readers(302) in response to the communication signal. When any reader 10 already allocated exists, the wireless communication device 200 will decide for being confliction existence between readers. When it has been decided for being confliction existence between readers, the wireless communication device 200 transmits NACK signal or no answer signal to the reader which has been tried to communicate with, and let the reader wait for allocating of current communication. Otherwise, when it has been decided for not being any confliction possibility, the wireless communication device 200 transmits ACK signal to the reader 10(303), so that the using of communication channel is permitted. The reader 10 which received ACK signal from the wireless communication device 200 transmits a query signal for trying to read or write tag information(304). Then, the wireless communication device 200 amplifies the query signal from the reader 10, and transmits the amplified high- powered query signal to the tag in the tag zone 102. When the tag 20 receive a query signal from the wireless communication device, the tag 20 will be activated using the received power, and will transmits its unique information to the reader 10 using the scattered modulation(306). Then, the reader 10 goes through a process that reads information of tag or writes data to the same tag 10. When the process of reading or writing is not completed, the reader 10 will continue to perform the process of 304 ~ 308, otherwise the reader 10 completes recognition process of RF(309). The completion of communication may be performed by the reader 10, or may be performed by the wireless communication device 200, such as the wireless communication device 200 controls completion(309) or beginning(300) by arranging the readers 10 being waiting.

[63] The invention is not limited to what has been described herein above merely by way of example. While there have been described what are at present considered to be the preferred embodiments of this invention, it will be obvious to those skilled in the art that various other embodiments, changes, and modifications may be made therein without departing from the spirit or scope of this invention and that it is, therefore, aimed to cover all such changes and modifications as fall within the true spirit and scope of the invention, for which letters patent is applied.

Claims

[1] An extensive RFID system for reader- tag communication for performing communications between at least one of RFID reader and passive tag, the RFID system comprising: a wireless communication device including a communication means for amplifying a weak signal from a low-powered reader to high-powered signal through communication with the reader to extend distance of reading and writing information between reader and tags, and for transmitting the high-powered signal to the tags.

[2] An extensive RFID system for reader-tag communication according to claim 1, wherein the wireless communication device is independently installed in a way that is separated with the RFID reader, and forms a certain area of reader zone be able to communicate with at least one of tags for communication with the RFID reader and a certain area of tag zone be able to cover at least one of passive tag by amplifying weak signal of the reader.

[3] An extensive RFID system for reader-tag communication according to claim 1, wherein the wireless communication device comprises, a signal processor for selecting only desired signal from reader signals and converting the desired signal to a predetermined low-frequency signal; an amplifying/transmitting portion for amplifying the reader signal and transmitting the amplified signal to tags; a communication order arranging portion for arranging an order of communication for a plurality of readers, and sending to the reader; a control portion for performing control function of analyzing and storing reader signal and controlling the signal processor and the amplifying/transmitting portion and the communication order arranging portion; and a memory for storing command information of the reader obtained from wireless communication between at least one of readers.

[4] An extensive RFID system for reader-tag communication according to claim 1, wherein the wireless communication device comprises, A means for communicating with each reader to prevent confliction between readers when a plurality of readers exist so that order of communication through communication channel between the each reader and tags.

[5] An extensive RFID system for reader-tag communication according to claim 4, wherein the wireless communication device further comprises, a memory for storing command information of the reader obtained from wireless communication between at least one of readers.

[6] RFID recognition method performed in an extensive RFID system for reader-tag communication for performing communications between at least one of RFID reader and passive tags and wireless communication device, wherein the wireless communication device includes a communication means for amplifying a weak signal from low-powered reader, forwarding the amplified signal to a plurality of passive-type tags, and communicating with each reader to prevent confliction between readers: transmitting a communication signal to the wireless communication device for occupying a communication channel by the reader; arranging and deciding final order of communication in response to the communication signal by the wireless communication device; transmitting a query signal to the wireless communication device according to the decided communication order by the reader; amplifying a query signal from a reader finally decided in order of communication and transmitting the amplified signal to tags in tag zone; activating of the tag by receiving reader's fquery signal and transmitting a response signal to a reader in recognition zone during backscatter modulation process; and reading or writing a tag information using the response signal of the tag by the reader.

[7] RFID recognition method according to claim 6 further comprises: confirming completion of a reader-tag communication and allocating next communication order for another reader; monitoring an inadequate command from reader and storing the same to the memory by the wireless communication device; sending or alerting of the inadequate command from the reader by the wireless communication device.