CN101169817B - Radio frequency identification tag system and tag thereof - Google Patents

Abstract

The present invention discloses a radio frequency identification tag system and its data stream, wherein the radio frequency identification tag system comprises at least one radio frequency identification tag and a reader. The first plurality of bits of the radio frequency identification tag output data stream are set as a sequence of determined values, and the bits after the sequence are main data. The reader can detect the frequency of the code of the data stream output by the radio frequency identification tag according to the known determined values in the sequence, and read the main data using the detected frequency.

Description

RFID tagging system and its tags

technical field

The present invention relates to a radio frequency identification tag system and its data stream, in particular to a high identification rate radio frequency identification tag system and its data stream which can transmit data in different frequency bands. the

Background technique

With the popularity of radio frequency identification systems, the application of barcodes has gradually been replaced. Wal-mart, a major retailer in the United States, has asked its top 100 suppliers to use radio frequency identification tags on all packaging boxes and shelves before January 1, 2005, and the German chain store Metro (Metro) uses radio frequency identification tags A store of the future that recognizes shelves also opened in May 2004. The reason why these large international retailers are determined to introduce the radio frequency identification tag system is that they are convinced that the introduction of radio frequency identification technology will greatly improve the efficiency of product management. the

However, in the early stages of the development of radio frequency identification technology, the lack of consensus on the use of frequency bands, different standards for label formats, and high costs have deterred those who want to participate. In order to solve these problems, EPCglobal (Electronic Product Code Global) cooperates with MIT Auto-Lab to provide suppliers of radio frequency identification products with detailed specifications and specifications of various radio frequency hardware and software interfaces. The document also proposes a new radio frequency identification tag protocol, the EPC communication protocol. the

The EPC communication protocol is an expandable coding system, which can be adjusted and designed according to the needs of different industries, so as to give unique codes to items. According to the currently published EPC label specifications, there is a difference between 96-bit and 64-bit label capacity, and 256-bit codes will appear in the future, and the label capacity can be selected according to user needs; the code structure can be adjusted according to the size of the capacity. The basic encoding method (General Identifier; GID) is to divide the EPC code structure into four blocks: Header, General Manager Number, Object Class and Serial Number ). the

Since the current EPC communication protocol is quite complicated in the definition of data flow, the tag itself must have functions such as precise frequency output, complex frequency synchronization and frame synchronization, so that the reader (reader) and the tag can achieve A stable one-way transmission, or even two-way transmission is required. Once either the reader or the tag fails to meet the above conditions, the wireless communication path will fail to connect and the recognition rate will be reduced. the

In addition to the bottleneck in the improvement of the recognition rate, the cost of the standard silicon semiconductor process used in the manufacture of labels is also too high, and the relative production speed cannot keep up with the rapid growth of demand. Therefore, the low-cost and simple printed circuit process technology is gradually attracting attention and attention. discuss. Compared with the silicon semiconductor process, the printed circuit process has the advantages of low price and simple process, but it also has the disadvantage of large variations in the electrical characteristics of the components and process results. If the existing radio frequency tag data flow specification is combined with the printed circuit process, there will be disadvantages such as high circuit integration, low pass rate, high cost, and large power consumption. It is really a very difficult and difficult to implement project. The advantages of such printed circuit technology will not be able to be introduced into the existing label manufacturing at all. the

Therefore, there is an urgent need for a new radio frequency tag data stream in the market, which can not only process the transistor technology with large process variation and is not easy to be highly integrated integrated circuit (such as: OTFT, a-Si TFT, LTPS TFT and other transistor technology) or After the implementation of the printed circuit process is completed, radio frequency identification tags with high performance, low power consumption and high recognition rate can still be obtained. the

Contents of the invention

The purpose of the present invention is to provide a radio frequency identification tag system and its data flow, which is set at the beginning of the radio frequency identification tag output data stream as a series of definite values, and determine the radio frequency by reading the series. The frequency of the output signal of the identification tag, so the present invention can adapt to the radio frequency identification tag manufactured under the situation of low-cost process results and large variation. That is, even if the center frequency drifts due to process variation, it will not affect the data reading of the radio frequency identification tag system. the

Another object of the present invention is to provide a high recognition rate radio frequency identification tag system, through the difference in the frequency band of the output signal of the radio frequency identification tag, the recognition rate of the radio frequency identification tag being read can be increased, and the difference in the frequency band can be as different identification marks. the

To achieve the above purpose, the present invention discloses a radio frequency identification tag system and its data flow, the radio frequency identification tag system includes at least one radio frequency identification tag and a reader. The plural bits at the beginning of the data stream output by the radio frequency identification tag are set as a series of definite values, and the bits after the series are main data. The reader can detect the frequency at which the RFID tag outputs the code of the data stream according to the known values in the sequence, and use the detected frequency to read the main body data. the

Through the ability of the radio frequency identification tag system of the present invention to identify frequencies, it can be applied to radio frequency identification tags manufactured under the situation of low-cost process results and large variations, that is, instead, the poor characteristics of frequency drift caused by process variations are used to form A radio frequency identification tag system with frequency separation and high identification rate. the

Description of drawings

Fig. 1 illustrates the structure of the data flow of radio frequency identification tag system of the present invention;

Fig. 2 is the coding waveform diagram of the data flow of the radio frequency identification tag system of an embodiment of the present invention; And

Fig. 3 is a functional block diagram of the radio frequency identification tag system of the present invention. the

Detailed ways

FIG. 1 is a structural diagram of the data flow of the radio frequency identification tag system of the present invention. The data stream 10 includes a preamble 11, a main body data 12 and an end code 13 (End Of File; EOF), wherein the end code depends on the actual needs of the system to determine whether it is necessary. The subject data 12 includes data that can be used for identification, such as: identification code, serial number, and object type code. The preamble 11 can be regarded as a synchronous code, not only as the beginning of the data stream 10, but also to ensure the synchronization of the transmission signal frequency and the read frequency of the data stream 10. the

FIG. 2 is a coded waveform diagram of the data stream of the radio frequency identification tag system of the present invention. In this embodiment, the first five bits of the data stream are selected as the leader, and the next leader is the main body data. As shown in this figure, the leading data can be set to be a numerical sequence 11111, and the main data can be a binary value 101011. When the reader (not shown) is close to the radio frequency identification tag (not shown) with the data stream in Figure 2, although the sequence stored in the preamble is known to be 11111, the frequency or period of the digital clock needs to be based on the The known sequence of 11111 can be detected and confirmed. Generally, the frequency of the digital clock can be locked by over sampling (over sampling) method and digital signal processing (Digital Signal Processing; DSP), or by phase lock loop (Phase Lock Loop; PLL) to determine the frequency. When the reader confirms the signal frequency or digital clock frequency of the data stream, the content of the main data can be read correctly. the

Fig. 3 is a functional block diagram of the radio frequency identification tag system of the present invention. The radio frequency identification tag system 30 includes at least one radio frequency identification tag 32 and a reader 31 , and performs data transmission between the radio frequency identification tag 32 and a reader 31 through electromagnetic field inductive coupling. When the antenna 321 of the RFID tag 32 is changed by the electromagnetic field to generate current, the current will be converted into a stable DC current by a rectifier 323 to supply other circuits of the RFID tag 32 . the

In Fig. 2, the leading and main body data are stored in the memory 326, and the controller 327 can read the data stored in the memory 326 according to the standard digital clock frequency generated by the oscillator (oscillator) 324 (such as a ring oscillator), and sequentially The read data is sent to an encoder (encoder) 325 (such as a Manchester encoder) for encoding. The encoding waveform diagram shown in Figure 2 is a waveform after Manchester encoding, that is, the voltage changes from positive potential to negative potential within a digital clock cycle to represent 1, and vice versa to represent 0. The characteristic of this encoding is to make the data The transmitting end (radio frequency identification tag 32 ) and the receiving end (reader 31 ) achieve a synchronization effect during data transmission and reception. However, the encoding of the data stream of the present invention is not limited to Manchester encoding, for example: pulse width modulation (Pulse Width Modulation; PWM) encoding, non-return to zero inversion (Non Return to Zero Invert; NRZI) modulation or return-to-zero modulation ( Return to ZeroModulation). The coded data stream needs to be modulated by the modulator 322 before it can be transmitted from the antenna 321 to the reader 31, so that the digitally coded data stream can become a radio frequency signal simulated by the chip. the

Through the ability of the radio frequency identification tag system 30 of the present invention to identify the frequency, it can be applied to the radio frequency identification tag 32 manufactured under the situation of low-cost process results and large variations, that is, the poor characteristics of frequency drift caused by process variation instead, A radio frequency identification tag system 30 with frequency separation and high identification rate is formed. In addition, with the encoder 325 and the memory 326 with a capacity of 64K, the number of transistors on the radio frequency identification tag 32 chip will be less than 200. Compared with the EPC standard label that requires tens of thousands of transistors, the radio frequency identification tag 32 of the present invention It will greatly reduce the circuit integration level. the

The technical content and technical features of the present invention have been disclosed above, but those skilled in the art may still make various substitutions and modifications based on the teaching and disclosure of the present invention without departing from the spirit of the present invention. Therefore, the protection scope of the present invention should not be limited to the contents disclosed in the embodiments, but should include various replacements and modifications that do not depart from the present invention, and are covered by the scope of the appended claims. the

Claims (14)

1. radio frequency identification label system is characterized in that comprising:

At least one RFID tag is exported a data stream, and a plurality of positions that described data stream begins are set at the ordered series of numbers of determining numerical value; And

One reader according to fixed number value really in the described ordered series of numbers, detects the frequency of exporting the coding of described data stream from described RFID tag.

2. radio frequency identification label system as claimed in claim 1 is characterized in that described ordered series of numbers is recorded in described data stream leading.

3. radio frequency identification label system as claimed in claim 2 is characterized in that described data stream comprises that described one can be for the body data of identification identity data after leading in addition.

4. radio frequency identification label system as claimed in claim 3 is characterized in that described data stream comprises identity code, sequence number or object classification sign indicating number.

5. radio frequency identification label system as claimed in claim 3 is characterized in that described data stream comprises an end code in addition after described body data.

6. radio frequency identification label system as claimed in claim 1 is characterized in that described RFID tag comprises that in addition one can store the storer of described data stream.

7. radio frequency identification label system as claimed in claim 6 is characterized in that described RFID tag comprises a controller, and described controller reads the described data stream of described store memory storage with reference to a standard digital clock.

8. radio frequency identification label system as claimed in claim 7 is characterized in that described standard digital clock is produced by an oscillator.

9. radio frequency identification label system as claimed in claim 7 is characterized in that described standard digital clock is produced by a circular type shaker.

10. radio frequency identification label system as claimed in claim 1 is characterized in that described RFID tag comprises that one can carry out binary-coded scrambler with described data stream.

11. radio frequency identification label system as claimed in claim 10 is characterized in that described scrambler adopts the Manchester's cde mode to carry out the binary coding of described data stream.

12. a label that is used for radio frequency identification label system is characterized in that described label exports a data stream, described data stream comprises:

One is leading, is positioned at a plurality of positions that described data stream begins, and is set at the ordered series of numbers of determining numerical value, and described ordered series of numbers is represented the verification msg of coding frequency in the described radio frequency identification label system; And a body data, record can be for the data of identification identity.

13. the label that is used for radio frequency identification label system as claimed in claim 12 is characterized in that described body data comprises identity code, sequence number or object classification sign indicating number.

14. the label that is used for radio frequency identification label system as claimed in claim 12 is characterized in that comprising in addition an end code that is positioned at after the described body data.

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