CN101957923A - Method and reader for reading data from tags in radio frequency identification system - Google Patents

Abstract

The present invention proposes a method for reading data in tags in a radio frequency identification system, the radio frequency identification system includes more than one reader and a group of tags, and each tag contains a data and a set of characteristics Descriptive information, in this method, firstly, the first reader-writer or the tag uses a code with error correction and error detection capabilities to code the feature description information and write the code into the tag; then The first reader-writer or the second reader-writer reads the tag, receives the encoded feature description information, and decodes the feature description information through the encoding; finally, the The first reader-writer or the second reader-writer reads corresponding data according to the decoded feature description information. The invention protects the feature description information in the tag, thereby effectively helping the reader-writer to grasp the feature of the tag and read the storage data of the tag more accurately.

Description

Method and reader for reading tag data in radio frequency identification system

technical field

The invention relates to radio frequency identification (Radio Frequency Identification, referred to as RFID) technology, in particular to a method for reading tag data in a radio frequency identification system and a reader/writer for realizing the method.

Background technique

Recently, UHF radio frequency identification (RFID) technology has received increasing attention. With the ability to identify hundreds of unique objects per second, UHF RFID creates many application opportunities in logistics-related situations. With the rapid development of new technologies, such as near-field UHF technology, battery-assisted passive tags, etc., UHF RFID is also considered as a potential solution for manufacturing applications such as pharmaceutical production line operations. Since UHF RFID conforms to the global EPC C1G2 standard (EPC Radio-Frequency Identity Protocols Class-1 Generation-2 UHF RFID Protocol for Communications at 860MHz-960MHz), it has unique advantages such as high-speed read/write, and is different from traditional Better performance can be achieved compared to HF band solutions.

However, in manufacturing applications, the reliability of tag read/write is critical to the continuous operation of the production line. For these applications, the biggest challenge for UHF RFID is the poor reliability of read/write operations. For all read/write operations, the first step is to read the Electronic Product Code (Electronic ProductCode: EPC) in the EPC C1G2 standard. It can be said that the reliability of EPC reading will determine the reliability and speed of the entire read/write program.

Generally, there are three situations that may cause the failure of reading EPC, namely: the timeout of the reader reading the RN16 prefix, the timeout of the reader reading the EPC data prefix, and the error of the CRC check of the EPC data by the reader. As shown in Figure 1, the process of reading the EPC can be divided into two stages. First, the reader (Reader) sends a query command Query to the tag (Tag), and then the tag sends a 16-bit random number or pseudo-random data (RN16) as a handle to the reader. Next, the reader sends an ACK command with a valid handle to the tag. After receiving the ACK command, the tag backscatters its EPC data. In addition to the EPC code, the EPC data also includes protocol control bits (ProtocolControl; PC) and cyclic redundancy check bits (Cyclic Redundancy Check; CRC). If the capture of RN16 prefix or EPC data prefix fails, it will cause RN16 timeout and EPC timeout respectively. In addition, invalid handles due to label conflicts can also cause EPC timeouts. In addition, since the reader only uses CRC for verification during the EPC reading process, some wrong bits in the EPC transmission will cause CRC errors when the reader performs CRC verification, and even cause the EPC to receive fail.

Since the tag design is very simple, tags are generally not required to communicate using complex methods (eg, source and channel coding) to reduce the chances of these three situations occurring. In the patent application 200810004983.0 of Siemens AG, a "method and device for providing energy to passive tags in a radio frequency identification system" is proposed, which can better solve the first two failure situations. However, in many UHF RFID applications, such as manufacturing applications, due to the simple design of the tag, a large amount of interference will make the reader unable to receive EPC correctly, resulting in CRC errors when the reader reads EPC data. However, for many applications that have special requirements on read/write speed, the receiving efficiency and reliability of EPC data are very important.

In the prior art, there are some solutions to the problem that the reader/writer cannot receive the EPC correctly, resulting in CRC errors when the reader/writer reads the EPC data. For example, in the process of receiving EPC data, once an error occurs when some readers (such as ALR8800) read EPC data, the reader can retransmit the acknowledgment command ACK, so that the EPC data cannot pass the test again. Perform label backscatter EPC data.

However, as shown in Figure 2, due to the unsatisfactory end of the signaling, it is difficult for the reader to detect the end of the tag backscattered transmission. The reader can only rely on the first byte of the protocol control bit PC in the EPC data to determine the number of bits to be received during the EPC receiving process (the two-byte PC data contains the EPC code, or the length of the EPC data) . Fig. 3 shows a basic flowchart of obtaining an EPC code by retransmitting an acknowledgment command ACK in the prior art.

First, the reader sends a query command Query to the tag. After receiving the query command Query, the tag returns a 16-bit random number RN16 as a handle to the reader. If the reader does not receive the random number RN16, the reader resends the query command Query after a period of time.

Secondly, after receiving the random number RN16 sent by the tag, the reader/writer sends an acknowledgment command ACK to the tag. After the tag receives the confirmation command ACK, it returns the prefix of the electronic product code EPC data to the reader. If the reader does not detect the prefix, the reader resends the query command Query after a period of time.

Again, the reader receives the first byte of the protocol control bit PC, and obtains the length of the EPC code therefrom (because the length of the protocol control bit PC is fixed and the length of the cyclic redundancy check CRC is fixed, the length of the EPC code is obtained length to get the length of the entire electronic product code EPC data).

Then, the reader sets the data bits to be received as the length of the EPC code plus 32 bits, and prepares to receive data.

After a waiting period, the reader/writer receives the data of the electronic product code EPC data. Subsequently, the reader performs a cyclic redundancy check (CRC) on the received data. If the verification is passed, the reader sends the next query command QueryRep to the tag; if the verification fails, the reader resends the confirmation command ACK to the tag and detects the prefix of the product code EPC data.

If the reader can detect the PC correctly, the process shown in Figure 3 can solve the CRC error problem. However, if some errors occur during receiving the PC, the reader will analyze the EPC length incorrectly. Then a lot of time will be wasted for sending the next command, as shown in Figure 4. The upper figure in Figure 4 shows the original length of the EPC data, and the lower figure in Figure 4 shows that the reader failed to receive the PC correctly, so it misjudged the length of the EPC data. In the worst case, the wasted time may be as long as (496+32-8)*0.025=13ms. The normal EPC reading process takes only about 2-3ms. On the other hand, the tag will not respond to the next command because it has timed out due to loss of synchronization. Thus, the wrong reception of the PC will affect the reliability and efficiency of the whole system to a great extent.

Contents of the invention

The main purpose of the present invention is to provide a method for reading the data in the tag in the radio frequency identification system and a reader/writer for realizing the method, which can protect the feature description information of the tag during the process of reading and writing the tag , so that the reader/writer can correctly detect and receive the characteristic description information, so as to obtain the data in the tag correctly.

In order to achieve the above purpose, a method for reading data in a tag in a radio frequency identification system, the radio frequency identification system includes more than one reader and a group of tags, each tag contains a set of data and A set of feature description information, the method includes the following steps:

(1) The first reader-writer or the tag uses a code with error correction and error detection capabilities to code the feature description information and write the code into the tag;

(2) The first reader-writer or the second reader-writer reads the tag, receives the encoded feature description information, and decodes the feature description information through the encoding;

(3) The first reader-writer or the second reader-writer reads corresponding data according to the decoded feature description information.

As a preferred solution, in the step (1), the code with error correction and error detection capabilities includes an error detection code (EDC) and an error correction code (ECC).

According to an embodiment of the present invention, the data of the tag is the data in the electronic product code (EPC) data area, the feature description information of the tag is the protocol control bit (PC), and the electronic product code (EPC) data The length of the electronic product code (EPC) in the zone is recorded in the protocol control bit (PC),

In the step (1), the first reader/writer uses the error detection code (EDC) and the error correction code (ECC) to encode the protocol control bit (PC), and encodes the encoded Write in the label electronic product code (EPC) data;

In the step (2), the first reader-writer or the second reader-writer reads the electronic product code (EPC) data in the label, and receives the encoded protocol control bit (PC ), and decode the encoded protocol control bit (PC);

In the step (3), the first reader-writer or the second reader-writer sets the data bit to be received according to the decoded protocol control bit (PC) and prepares to receive data.

As a preferred version of the present invention, the step (1) includes the following steps:

(11) the recorded length of the protocol control bit (PC) is set to the sum of the lengths of the electronic product code (EPC), error detection code (EDC), and error correction code (ECC);

(12) setting a protection flag on the reserved bit (RFU) of the protocol control bit (PC);

(13) calculating the error detection code (EDC) for the protocol control bit (PC);

(14) calculating said error correction code (ECC) for said protocol control bit (PC) and said error detection code (EDC);

(15) Storing the error detection code (EDC) and the error correction code (ECC) to the beginning of the electronic product code (EPC).

As a preferred solution of the present invention, in the step (2), the decoding of the encoded protocol control bit (PC) by the first reader-writer or the second reader-writer further includes:

The first reader-writer or the second reader-writer performs error detection and correction on the protocol control bit (PC) and the error detection code (EDC) through the error correction code (ECC);

The first reader-writer or the second reader-writer performs error detection on the protocol control bit (PC) through the error detection code (EDC), so as to obtain the correct length of the electronic product code (EPC).

As a preferred solution of the present invention, if the error detection code (EDC) detects that the protocol control bit (PC) is wrong, the first reader-writer or the second reader-writer sends the The length of the electronic product code (EPC) is set to the length of the previous label's electronic product code (EPC). Or, if the error detection code (EDC) detects that the protocol control bit (PC) has an error, then the first reader-writer or the second reader-writer sends the received electronic product code (EPC) The length is set to 96 bits. Or, if the error detection code (EDC) detects that the protocol control bit (PC) has an error, the first reader-writer or the second reader-writer first waits to read the longest electronic product code ( EPC), and then start a new tag reading process, wherein the longest electronic product code (EPC) is 496 bits.

As a preferred solution of the present invention, in the step (3), the data bits to be received by the first reader-writer or the second reader-writer are set to the length of the electronic product code (EPC) plus 32 bits .

As a preferred solution of the present invention, if the length of the electronic product code (EPC) changes, the first reader-writer writes the error detection code (EDC) and the error correction code (ECC) again into the electronic product code data.

As a preferred solution of the present invention, before the step (1), the following steps are also included: the first reader-writer or the second reader-writer sends a protection label selection command to the label in its read-write area, Selecting the label with the protection mark set on the reserved bits (RFU) in the read-write area. In addition, after the step (3), it also includes: the first reader-writer or the second reader-writer sends a general label selection command to the tags in the read-write area, and selects the pre-selected tags in the read-write area. The common label without the protection mark is set on the left bit (RFU), and the data in the common label without the protection mark is read according to the common reading steps.

As a preferred solution of the present invention, before the step (1), it also includes: setting a register protection mode category identification in the first reader-writer or the second reader-writer, the register is in the first protection mode , continue to step (1).

As a preferred solution of the present invention, the first reader-writer or the second reader-writer selects at least one of the period of waiting to receive RN16 and the period of waiting to receive Electronic Product Code (EPC) data as the enhanced period, and the read-write The transmitter adjusts the gain of the transmission signal, so that the carrier signal in the enhancement period is transmitted with enhanced transmission power.

According to the second embodiment of the present invention, the data of the tag includes data in the electronic product code (EPC) data area and data in the user data area, and the feature description information of the tag is a protocol control bit (PC), The protocol control bit (PC) identifies whether there is valid data in the user data area,

In the step (1), the first reader/writer uses the error detection code (EDC) and the error correction code (ECC) to encode the protocol control bit (PC), and encodes the encoded Write in the label electronic product code (EPC) data;

In the step (2), the first reader-writer or the second reader-writer reads the electronic product code (EPC) data in the label, and receives the encoded protocol control bit (PC ), and decode the encoded protocol control bit (PC);

In the step (3), the first reader-writer or the second reader-writer determines whether to initiate a data read command according to the decoded protocol control bit (PC), and reads the data in the user data area. Pick.

According to a preferred solution of the second embodiment of the present invention, the step (1) includes the following steps:

(11) the recorded length of the protocol control bit (PC) is set to the sum of the lengths of the electronic product code (EPC), error detection code (EDC), and error correction code (ECC);

(12) setting a protection flag on the reserved bit (RFU) of the protocol control bit (PC);

(13) calculating the error detection code (EDC) for the protocol control bit (PC);

(14) calculating said error correction code (ECC) for said protocol control bit (PC) and said error detection code (EDC);

(15) Storing the error detection code (EDC) and the error correction code (ECC) to the beginning of the electronic product code (EPC).

According to a third embodiment of the present invention, the data of the tag includes data in the electronic product code (EPC) data area and data in the user data area, and the feature description information of the tag is the protocol control bit (PC) and Extended protocol control bit (XPC), which identifies the recallable state after the tag is killed, in the extended protocol control bit (XPC),

In the step (1), the first reader-writer uses the error detection code (EDC) and the error correction code (ECC) to the protocol control bit (PC) and the extended protocol control bit ( XPC) is encoded, and the encoding is written in the label;

In the step (2), the first reader-writer or the second reader-writer reads the tag, and receives the encoded protocol control bits (PC) and extended protocol control bits (XPC) , and decoding the encoded protocol control bit (PC) and extended protocol control bit (XPC);

In the step (3), the first reader-writer or the second reader-writer determines the recallable state of the tag according to the decoded protocol control bits (PC) and extended protocol control bits (XPC).

According to a preferred solution of the third embodiment of the present invention, in the step (1), the first reader/writer uses the error detection code (EDC) and the error correction code (ECC) to The protocol control bit (PC) and the extended protocol control bit (XPC) are encoded, and writing the encoding into the label includes the following steps:

(11) the recorded length of the protocol control bit (PC) is set to the sum of the lengths of the electronic product code (EPC), error detection code (EDC), and error correction code (ECC);

(12) setting a protection flag on the reserved bit (RFU) of the protocol control bit (PC);

(13) calculating the error detection code (EDC) for the protocol control bit (PC);

(14) calculating said error correction code (ECC) for said protocol control bit (PC) and said error detection code (EDC);

(15) Storing the error detection code (EDC) and the error correction code (ECC) in the tag.

According to a preferred solution of the third embodiment of the present invention, in the step (15), the error detection code (EDC) and the error correction code (ECC) are stored in the electronic product code (EPC) the starting position of . Alternatively, in the step (15), the error detection code (EDC) and the error correction code (ECC) are stored in the extended protocol control bit (XPC).

The present invention also proposes another method for reading data in tags in a radio frequency identification system, the radio frequency identification system includes more than one reader and a group of tags, each tag contains an electronic product code (EPC) data in the data area, each of the electronic product code (EPC) data includes a protocol control bit (PC), an electronic product code (EPC), a cyclic redundancy check bit (CRC), it is characterized in that the The method includes the following steps:

(1) An interface is defined between the reader-writer and the host connected to the reader-writer, and the host configures the length of the electronic product code (EPC) as a fixed length through the interface;

(2) The reader stores the length of the electronic product code (EPC) configured by the host in its register;

(3) When the reader-writer reads the data in the label, obtain the length of the electronic product code (EPC) of the label from the register of the reader-writer;

(4) The reader/writer sets the data bits to be received and prepares to receive data.

According to a preferred solution of another method, in the step (4), the data bit to be received by the reader-writer or the second reader-writer is set to the length of the electronic product code (EPC) plus 32 bits .

According to a preferred solution of another method, before the step (1), it also includes: setting a register protection mode category identifier in the reader, and when the register is in the second protection mode, continue the step (1).

According to a preferred solution of another method, the reader-writer selects at least one of the period of waiting to receive RN16 and the period of waiting to receive Electronic Product Code (EPC) data as the enhanced period, and the reader-writer adjusts the response to the transmitted signal. Gain, so that the carrier signal in the enhanced period is sent out with enhanced transmit power.

Correspondingly, the present invention proposes a reader/writer for reading data in tags in a radio frequency identification system, wherein the reader/writer includes:

An encoding unit, configured to encode feature description information using an encoding with error correction and error detection capabilities;

a writing unit, configured to write the code into a tag;

a reading unit, configured to read the data in the tag, and receive the encoded feature description information;

a decoding unit, configured to decode the feature description information through the encoding;

The receiving unit is configured to read corresponding data according to the decoded feature description information.

As a preferred solution of the present invention, the writing unit further includes:

The setting unit is used to set the length of the protocol control bit (PC) in the label to the sum of the lengths of the electronic product code (EPC), error detection code (EDC), and error correction code (ECC), and in the protocol A protection flag is set on the reserved bit (RFU) of the control bit (PC);

a calculation unit, configured to calculate the error detection code (EDC) for the protocol control bit (PC), and calculate the error correction code (EDC) for the protocol control bit (PC) and the error detection code (EDC) ECC);

A storage unit for storing the error detection code (EDC) and the error correction code (ECC) at the beginning of the electronic product code (EPC).

As a preferred solution of the present invention, the reader-writer also includes a command issuing module, which is used to send a protection label selection command to the tags in its read-write area, and selects the reserved bits in the read-write area ( RFU) is set with the label with the protection mark; or send a common label selection command to the label in its read-write area, and select the reserved bit (RFU) in the read-write area without setting the protection mark ordinary tags, and read the data in the ordinary tags without the protection mark according to the ordinary reading steps.

Corresponding to another method for reading data in a tag in a radio frequency identification system, the present invention also proposes a reader-writer, which includes:

An interface unit, configured to define an interface between the reader-writer and the host computer connected to the reader-writer, through which the host computer configures the length of the electronic product code (EPC) as a fixed length;

a storage unit, configured to store the length of the electronic product code (EPC) configured by the host in the register of the reader;

The reading unit is used to obtain the length of the electronic product code (EPC) of the tag from the storage of the reader when reading the data in the tag;

The receiving unit is configured to set the data bits to be received and prepare to receive data.

The method and device for reading the data in the tag in the radio frequency identification system of the present invention have the following advantages:

Firstly, the present invention protects the feature description information in the tag, thereby effectively helping the reader to grasp the tag's feature and read the stored data of the tag more accurately. Through the method provided by the invention, the reader can find the correct EPC length before receiving the EPC bits. The reader will be well synchronized with the tag and will not spend unnecessary time waiting for the tag to respond, thus improving efficiency. On the other hand, due to the good synchronization, the reader can send the ACK command at the correct time to request the EPC again, which will greatly improve the reliability.

Second, the reader rapidly increases power to capture the T2R preamble by supplying energy to the tag. Combining the method of the present invention with the above-mentioned method for supplying energy to the tag, the reliability can be further improved without causing great interference to other devices. Based on these two advantages, the method provided by the present invention is very suitable for occasions with large interference and multiple readers, such as manufacturing applications.

In addition, the implementation of the method of the present invention only needs to slightly modify the reader-writer, and because the method fully complies with the EPCC1G2 standard, the method of the present invention can be conveniently implemented in tags and reader-writers currently used, saving costs.

Description of drawings

The specific embodiment of the present invention is described in further detail below in conjunction with accompanying drawing, wherein:

FIG. 1 shows a schematic diagram of errors that may occur during the process of reading a tag by a reader/writer in the prior art;

Figure 2 shows the end state of the signal when the label backscatters in the prior art;

Fig. 3 has provided the flowchart of determining the EPC data length according to the first byte of the protocol control bit PC in the prior art;

FIG. 4 shows a schematic diagram of the reader/writer erroneously analyzing the length of the EPC due to certain errors in the receiving process of the protocol control bit PC in the prior art;

Fig. 5 has provided the schematic diagram of protocol control bit and extended protocol control bit;

Figure 6 shows the structure of the electronic product code EPC data after the reader writes an error detection code EDC and an error correction code ECC into the tag electronic product code EPC data;

Figure 7 shows when the first 5 bits of the protocol control bit are used to identify the EPC length of the label, or when the 6th bit of the protocol control bit is used to identify whether there is valid data in the user data area, a specific one in Figure 6 Error detection code EDC and a specific error correction code ECC;

Figure 8 shows the process of writing the length of the protected electronic product code EPC code into the protocol control bit PC;

Figure 9 shows the reading process of the reader to the tag protected by the protocol control bit PC;

Figure 10 shows a specific error detection code EDC and a specific error correction code ECC in Figure 6 when the REC bit in the extended protocol control bit is used to identify the recallable state after the tag is killed;

Figure 11 provides a schematic diagram of label classification query under the condition that there are common labels and protocol control bit PC protected labels;

Figure 12 shows the reading process of the reader to the tag protected by the protocol control bit PC and the reading process of the ordinary tag;

FIG. 13 shows a schematic diagram of selecting at least one of the two enhancement periods in Embodiment 3 to Embodiment 5 to adjust the gain of the transmission signal;

Figure 14 provides a schematic diagram of the interface defined between the reader and the host connected to it;

Figure 15 shows the process in which the reader reads the data in the label with the fixed product code bit EPC;

Figure 16 shows the setup used in the test to simulate a real manufacturing application with interference sources;

Figure 17 shows the comparative relationship between BER performance and interference power;

Figure 18 shows the relationship between the percentage of RN16 timeout and the interference power;

Figure 19 shows the time interval Tinit and TEPCRetry in the process of reading and writing;

Figure 20 shows a comparison chart between the time for reading a single tag normally and the time for reading a single tag using the solution of the present invention, wherein the BER range is (1e-4 to 1e-2);

Figure 21 shows a comparison chart between the time for reading a single tag normally and the time for reading a single tag using the solution of the present invention, wherein the BER range is (1e-2 to 5e-2);

Figure 22 shows the reading reliability comparison between the method of reading the tag and the method of supplying energy to the tag recorded in the Siemens patent application 200810004983.0 according to the present invention when the EPC code is fixed ;

Figure 23 shows the comparison of the reading rate obtained by the method of reading the tag under the condition that the EPC code of the present invention is fixed and the method of supplying energy to the tag recorded in Siemens patent application 200810004983.0.

Detailed ways

In RFID systems, data is stored in the tags. These data can be divided into two categories. One type of data is the data that is actually used in the RFID system; the other type of data is the data that describes the data that is actually used in the previous type. These data are called the characteristics of the label. Description. In more detail, all data in the tag is stored in three areas (Bank), these three areas are: Tag ID (TagID) area, Electronic Product Code (EPC) data area, user data (User Memory) )district. Among them, the feature description information of the tag is mainly stored in the front end of the electronic product code data area EPC, and the remaining data in the three areas are the data to be used in the radio frequency identification system after removing the feature description information.

The feature description information of the tag is mainly defined by the protocol control bit PC and the extended protocol control bit XPC (XPC is defined in the latest UHF RFID standard), as shown in Figure 5. In Figure 5, the protocol control bit PC consists of two bytes, and the definition of each bit is shown in the lower left figure. The extended protocol control bit XPC includes a W1 part and a W2 part, and each part consists of two bytes. At present, some bits in W1 have been defined, see the figure on the lower right, in which bit 0 is a reserved bit; and the part of W2 is a reserved byte, and no bit is currently defined.

The feature description information is mainly used to help the reader to grasp the characteristics of the tag so as to read the stored data of the tag more effectively. For example, the first 5 bits of the protocol control bit PC are used to identify the length of the EPC code in the electronic product code data area of the label, and the reader can set the length when reading the EPC according to this information. For another example, the sixth bit in the protocol control bit can be used to identify whether there is valid data in the user data area User Memory of the tag, and the reader can decide whether to initiate a data read command based on this information. In addition, the REC bit in the extended protocol control bit can identify the recallable state (Recommissioning) of the tag after being killed (Kill), and the reader can determine the recallable state of the tag based on this information, thereby judging the locking of the user data area Depending on the situation, different strategies are used to read data. In short, this kind of feature description information has a great impact on the efficiency of the reader to read and write tags. If an error occurs during the transmission process, the entire reading and writing process may fail. Therefore, how to reliably transmit this information becomes very critical.

The core idea of the present invention is to improve the reliability of tag data reading by protecting these characteristic description information, and the specific scheme includes the following steps:

First, the first reader/writer or tag uses a code with error correction and error detection capabilities to code the feature description information and write the code into the tag.

Secondly, the first reader-writer or the second reader-writer reads the tag, receives the encoded feature description information, and decodes the feature description information through encoding.

Finally, the first reader-writer or the second reader-writer reads corresponding data according to the decoded feature description information.

The specific implementation of the present invention will be described below by taking a radio frequency identification system composed of a reader-writer and a tag as an example.

In the radio frequency identification system, the reliability of the reader to read the tag depends to a large extent on the reader's capture of the RN16 prefix and the EPC data area in the process of receiving the data in the electronic product code data area. Data (hereinafter referred to as EPC data) prefix and the ability to correct CRC errors. EPC data includes protocol control bit PC, EPC code and cyclic redundancy check code CRC, and wherein the length information of EPC code is very important for the reader to understand the end of EPC backscattering, in the following embodiments of the present invention Part 1 will specifically describe how the reader/writer first protects the length information of the EPC code, and then the reader/writer receives the protected length information of the EPC code, so as to correctly receive the EPC data.

The radio frequency identification system of embodiment 1 of the present invention comprises more than one reader-writer and a group of tags, wherein each tag all contains EPC data, and EPC data further includes protocol control bit PC, EPC code, cyclic redundancy check bit CRC . Wherein, the length of the protocol control bit PC is 16 bits, the length of the EPC code can vary between 96 and 496 bits, and the length of the cyclic redundancy check bit CRC is 16 bits. The length of the EPC code is recorded in the protocol control bit PC.

When the reader reads a tag for the first time, it uses an error detection code (Error Detection Code; EDC) and an error correction code (Error Correction Code; ECC) to encode the protocol control bit PC, and encode Write it into the EPC data area of the tag electronic product code. Figure 6 shows the structure of written encoded EPC data. Among them, the first is the protocol control bit PC, which has a length of 16 bits, which is recorded as N1 bits here for the convenience of subsequent calculations. The protocol control bit PC usually uses five bits in the first byte to record the length of the EPC code. In addition to the above five bits, the protocol control bit PC also has some reserved bits (Reserved for Future Use; RFU), and the reader uses two bits of these reserved bits RFU to set a protection flag to identify the tag's The length information of the EPC code is protected. After the protocol control bit PC is the protection bit of Npro bit, including an error detection code EDC and an error correction code ECC. The sum of the N1 bits and the Npro bits is recorded as Np bits. Next is the EPC code, whose length is between 96 bits and 496 bits, denoted as N2 bits. The last is the cyclic redundancy check bit CRC, whose length is 16 bits.

Fig. 7 has provided a specific error detection code EDC and a specific error correction code ECC in Fig. 6, wherein the error detection code EDC selects the cyclic redundancy check code CRC of 5 bits, and the error correction code ECC selects BCH (31 , 21) code, wherein 21 represents that the coded length is 21 bits, that is, the protocol control bit PC of 16 bits adds the cyclic redundancy check code CRC as the error detection code of 5 bits; 31 represents that the coded BCH code length is 31 bits, so it can be seen that the length of the error correction code ECC here is 10 bits (that is, 31-16-5=10 bits). In other words, here the sum of the lengths of the error detection code EDC and the error correction code ECC is Npro=15 bits (5+10=15 bits).

Figure 8 shows the process of writing the length of the protected EPC code into the protocol control bit PC, including the following steps:

First, it is determined to change the length of the EPC code (that is, to change the length of the entire EPC data) in an open-loop application. The so-called open-loop application here means that the label may be used in multiple links, such as processing, logistics, distributors, retailers, users and other links. For example, for a distributor, it may receive various labels from different places, and the lengths of the EPC codes of these labels received from different places may be different. Furthermore, it can be known that for each of the above links, the length of the EPC code of the tag received from the previous link may be different, so it is necessary to protect the tags whose EPC code length changes.

Secondly, the reader sets the length recorded by the protocol control bit PC as the sum of the lengths of the EPC code, the error detection code EDC, and the error correction code ECC. That is, the lengths of the error detection code EDC and the error correction code ECC are regarded as a part of the EPC code.

Again, the reader sets a protection flag on the reserved bit RFU of the protocol control bit PC, indicating that the length information of the EPC code of the tag is protected. For example, the last two bits of the 16-bit protocol control bit PC may be used as the protection identifier.

Then, the reader calculates the error detection code EDC for the protocol control bit PC. This calculation step belongs to the prior art and will not be repeated here.

Next, the reader/writer calculates the error correction code ECC for the protocol control bit PC and the error detection code EDC. Like the previous step, this calculation step is a prior art.

Finally, the error detection code EDC and the error correction code ECC are stored at the beginning of the EPC code, and their positions are shown in the above-mentioned Fig. 6 and Fig. 7 . After that, the reader can start the normal reading procedure.

When the reader/writer reads the tag for the first time, it performs the operation of the above steps, that is to say, after the above steps, the length information of the EPC code of the tag is protected. If the length of the EPC code changes, for example, the aforementioned open-loop application changes, the reader needs to write the error detection code EDC and error correction code ECC into the electronic product code EPC data area again.

The above-mentioned writing process is completed by a reader-writer, however, this writing process does not have to be completed by the reader-writer, and the tag itself can also complete the above-mentioned writing process of the code.

When the above-mentioned reader-writer who writes the error detection code EDC and the error-correction code ECC or another reader-writer reads the data in the electronic product code EPC data area in the label, the reader-writer who reads passes By decoding, the information recorded by the protected protocol control bit PC can be obtained, and the correct length of the EPC code can be obtained. Figure 9 shows the reading process of the reader to the tag protected by the protocol control bit PC.

First, the reader sends a query command Query to the tag. After receiving the query command Query, the tag returns a 16-bit random number RN16 as a handle to the reader. If the reader does not receive the random number RN16, the reader resends the query command Query after a period of time.

Secondly, after receiving the random number RN16 sent by the tag, the reader/writer sends an acknowledgment command ACK to the tag. After the tag receives the confirmation command ACK, it returns the prefix of the electronic product code EPC data to the reader. If the reader does not detect the prefix, the reader resends the query command Query after a period of time.

Again, if the reader/writer detects the prefix of the electronic product code EPC data, the reader/writer reads the data in the electronic product code EPC data area of the label, and receives the protocol control bit PC, error detection code EDC, error Correction code ECC.

Then, the reader uses the error correction code ECC to perform error detection and correction on the protocol control bit PC and the error detection code EDC. That is to say, if the error correction code ECC detects an error in the protocol control bit PC and the error detection code EDC and has the ability to correct the error, the error correction code ECC will correct the error.

Next, the reader/writer performs error detection on the protocol control bit PC through the error detection code EDC. If an error is detected in the protocol control bit PC, the reader can take one of the following three ways to deal with it:

The first one is to set the length of the EPC code to be received to the length of the EPC code of the previous tag. This is assuming that the tag is of the same kind as the previous tag.

In the second type, the length of the EPC code to be received is set to 96 bits. 96 bits are EPC

In the third type, the reader first waits for the time required to read the longest EPC code, where the longest EPC code is 496 bits, and then starts a new tag reading process, that is, the reader resends the query command Query to label.

When the reader makes an error on the protocol control bit PC through the error detection code EDC, if no error is detected in the protocol control bit PC, it means that the reader has obtained the correct length of the EPC code; or the protocol control bit PC is detected above After the first and second error processing methods, it is assumed that the reader/writer has obtained the correct length of the EPC code. Therefore, the reader sets the data bits to be received as the length of the EPC code plus 32 bits, and prepares to receive data.

After a waiting period, the reader receives the electronic product code EPC data. Subsequently, the reader performs a cyclic redundancy check (CRC) on the received data. If the verification is passed, the reader sends the next query command QueryRep to the tag, and reports the received EPC data to the host connected to the reader. However, the EPC data reported to the host does not include the error correction code ECC and the error detection code EDC. If the verification fails, the reader resends the confirmation command ACK to the tag and detects the prefix of the product code EPC data.

In the second embodiment of the present invention, the sixth bit of the protection protocol control bit PC can be used to identify whether there is valid data in the user data area User Memory of the tag, and the reader/writer decides whether to initiate data based on this information. Read command.

Since the 6th bit to be protected and the first 5 bits to be protected for recording the length of the EPC code in the first embodiment are located in the protocol control bit PC, the protection process is similar to that in the first embodiment. Wherein, the same error detection code EDC and error correction code ECC as in the first embodiment can be used to encode the protocol control bit PC, and write the code into the EPC data area of the label electronic product code. The used error detection code EDC and error correction code ECC are shown in FIG. 7 , and the steps of using the error detection code EDC and error correction code ECC to encode the protocol control bit PC are shown in FIG. 8 . The reader/writer reads the electronic product code EPC data in the label, receives the encoded protocol control bit PC, and decodes the encoded protocol control bit PC. The process is shown in Figure 9. After decoding, the protocol control bit PC is obtained, and the sixth bit of the protocol control bit determines whether to initiate a data read command to read the data in the user data area.

In the third embodiment of the present invention, the REC bit of the extended protocol bit XPC is protected, which can identify the recallable state (Recommissioning) of the tag after being killed (Kill), and the reader can determine the recallable status of the tag based on this information Status, so as to judge the locking status of the user data area and adopt different strategies to read data. Its protection process is similar to the above two embodiments, the difference is:

First of all, since the REC bit is stored in the W1 part of the extended protocol bit XPC, what is to be protected in the third embodiment is the protocol control bit PC and the W1 part of the extended protocol control bit XPC, and the error detection code EDC used at this time and the error correction code ECC is different from the previous two. Figure 10(a) shows a specific error detection code EDC and a specific error correction code ECC in Figure 6 when the REC bit in the extended protocol control bit is used to identify the recallable state after the tag is killed . Among them, the error detection code EDC selects a 5-bit cyclic redundancy check code CRC, and the error correction code ECC selects a BCH (63, 39) code.

Secondly, the steps of encoding the protocol control bit PC using the error detection code EDC and the error correction code ECC are shown in Figure 8, only the protocol control bit PC in Figure 8 is changed to the protocol control bit PC and the extended protocol control bit XPC W1 part. In addition, an error detection code EDC and an error correction code ECC are stored in the tag. The difference from the previous two embodiments is that the codes here can be stored in different places of the label, and Fig. 10(b) and Fig. 10(c) respectively show these two storage methods. Since the W2 part of the extended protocol control bit XPC is currently reserved, the error detection code EDC and the error correction code ECC are stored in the W2 part of the extended protocol control bit XPC in FIG. 10( b ). However, in FIG. 10(c), the error detection code EDC and the error correction code ECC are stored at the beginning of the EPC code.

The reader reads the electronic product code EPC data in the label, receives the encoded protocol control bit PC and the extended protocol control bit XPC, and decodes the encoded protocol control bit PC and the extended protocol control bit XPC, The process is similar to that shown in Figure 9. After decoding, the protocol control bit PC and the extended protocol control bit XPC are obtained. The REC bit of the extended protocol bit XPC determines the recallable status of the label, thereby judging the locking status of the user data area and adopting different strategies to read data.

As a supplement to Embodiments 1 to 3, in the read/write area of the reader, there may be both tags whose protocol control bit PC is protected and ordinary tags whose protocol control bit PC is not protected. Fig. 11 shows a schematic diagram of label classification query under the condition that there are common labels and labels whose protocol control bit PC is protected. In this case, the reader first sends a selection command Select to all tags in its read-write area, and selects those tags with protection marks on the reserved bits RFU. The protocol control bit PC protected tag reading process shown in FIG. 9 is then initiated for these tags. Next, the reader sends a selection command Select to the tags in the read-write area to select the ordinary tags that do not have a protection mark on the reserved bit RFU in the read-write area, and then follow the normal reading steps to read the tags without Set the data in the normal tag of the protection flag to read.

Fig. 12 shows the reading process of the above-mentioned reader-writer on the tag whose protocol control bit PC is protected and the reading process of the common tag.

Of course, the reader can also choose to read the data in the ordinary tag first, and then choose to read the data in the tag whose protocol control bit PC is protected.

In addition, in the first embodiment, the solution is mainly aimed at solving the problem that any bit in the EPC data has an error during transmission during the process of receiving the electronic product code EPC data, causing the reader to generate a CRC check error. As mentioned in the background technology, there are three situations that may cause failure to read EPC data, namely: the reader reads the RN16 prefix timeout, the reader reads the EPC data prefix timeout, and the reader performs CRC check An error occurred. In the patent application 200810004983.0 of Siemens AG, solutions for the first two situations have been proposed. In order to further comprehensively improve the reliability of the reader to read the data in the tag, as an improved solution of Embodiment 1 of the present invention, the reader applies the solution for protecting the length of the EPC code of the present invention while , select the time period of waiting to receive RN16 as the enhanced period, in the enhanced period, the reader-writer adjusts the gain of the transmission signal, so that the carrier signal in the enhanced period is sent out with enhanced transmission power.

As another improved solution of Embodiment 1 of the present invention, while the reader/writer is applying the solution of protecting the length of the EPC code of the present invention, the time period for waiting to receive the electronic product code EPC data is selected as the enhanced period, during the enhanced period In this method, the reader/writer adjusts the gain of the sending signal, so that the carrier signal in the boosting period is sent out with the boosted sending power.

As yet another improved solution of Embodiment 1 of the present invention, while applying the solution for protecting the length of the EPC code of the present invention, the reader/writer chooses to wait for the time period for receiving RN16 and the time period for waiting to receive the electronic product code EPC data. The two time periods serve as enhanced periods. During these two enhanced periods, the reader/writer adjusts the gain of the transmitted signal, so that the carrier signal in the enhanced period is sent out with enhanced transmission power. FIG. 13 shows schematic diagrams of selecting at least one of the two enhancement periods in Embodiment 3 to Embodiment 5 to adjust the gain of the transmission signal.

The above embodiments and their improvements are all examples of applying the present invention to open-loop applications. But in addition to open-loop applications, there are also closed-loop applications in many cases. In closed-loop applications, labels typically only circulate within one system, for example, labels that circulate within a process. Because such labels are in a closed place, they usually do not enter the subsequent circulation, and they can generally be recycled. For tags in these closed-loop applications, the tag's EPC code is fixed. The present invention proposes another solution for the purpose of reliably reading EPC codes in closed-loop applications.

In Embodiment 4 of the present invention, the radio frequency identification system includes more than one reader-writer and a group of tags, wherein each tag contains EPC data, and the EPC data further includes protocol control bit PC, EPC code, cyclic redundancy The remaining check digit is CRC. Wherein, the length of the protocol control bit PC is 16 bits, the length of the EPC code is fixed, and can be fixed as a certain bit between 96 and 496 bits, and the length of the cyclic redundancy check bit CRC is 16 bits. The length of the EPC code is recorded in the protocol control bit PC.

According to the solution of the present invention, firstly, an interface is defined between the reader-writer and the host connected to it. The host configures the length of the EPC code as a fixed length n _EPC , and then transmits the length of the product code bit EPC to the reader through the interface.

Secondly, after receiving the length of the product code bit EPC, the reader/writer stores the length n _EPC of the EPC code in its register. Figure 14 shows a schematic diagram of the interface defined between the reader and the host connected to it.

After the above configuration and storage, the reader can read the data in the label with the fixed product code bit EPC. Figure 15 shows the process that the reader reads the data in the label with the fixed product code bit EPC.

First, the reader sends a query command Query to the tag. After receiving the query command Query, the tag returns a 16-bit random number RN16 as a handle to the reader. If the reader does not receive the random number RN16, the reader resends the query command Query after a period of time.

Secondly, after receiving the random number RN16 sent by the tag, the reader/writer sends an acknowledgment command ACK to the tag. After the tag receives the confirmation command ACK, it returns the prefix of the electronic product code EPC data to the reader. If the reader does not detect the prefix, the reader resends the query command Query after a period of time.

Again, if the reader/writer detects the prefix of the electronic product code EPC data, the reader/writer obtains the length n _EPC of the stored EPC code from its register. That is to say, in this embodiment, although the length of the EPC code is recorded in the protocol control bit PC, in actual use, the length information of the EPC code is not obtained from the protocol control bit PC, but read The writer obtains the length information of the EPC code from its register, so that it can be ensured that the length of the EPC code can be obtained even if an error occurs in the bit recording the EPC code length information in the protocol control bit PC during the process of reading the EPC data.

Then, the reader sets the data bits to be received as the length n _EPC of the EPC code plus 32 bits, and prepares to receive data.

After a waiting period, the reader receives the electronic product code EPC data. Subsequently, the reader performs a cyclic redundancy check (CRC) on the received data. If the verification is passed, the reader sends the next query command QueryRep to the tag, and reports the received EPC data to the host connected to the reader. If the verification fails, the reader resends the confirmation command ACK to the tag and detects the prefix of the product code EPC data.

Similar to the improved solution of the first embodiment, the fourth embodiment can also be combined with Siemens' patent application 200810004983.0 to further comprehensively improve the reliability of the reader to read the data in the tag. As an improved solution of Embodiment 4, while applying the solution of the present invention to read tags with fixed lengths of EPC codes, the reader selects the period of time waiting to receive RN16 as the enhanced period. During the enhanced period, reading and writing The converter adjusts the gain of the transmission signal, so that the carrier signal in the enhancement period is transmitted with the enhanced transmission power.

As another improvement of Embodiment 4, the reader/writer selects the period of waiting to receive the electronic product code EPC data as the enhanced period while applying the tag with a fixed length of the EPC code of the present invention. During the enhanced period, reading and writing The converter adjusts the gain of the transmission signal, so that the carrier signal in the enhancement period is transmitted with the enhanced transmission power.

As yet another improvement of Embodiment 4, while the reader/writer is applying the tag with a fixed length of the EPC code of the present invention, it selects the two periods of waiting to receive the RN16 period and waiting to receive the electronic product code EPC data as the two periods of time. Enhanced period, during these two enhanced periods, the reader-writer adjusts the gain of the transmitted signal, so that the carrier signal in the enhanced period is sent out with enhanced transmit power.

As mentioned above, Embodiment 1 and its improved solution are solutions for reading tags in open-loop applications, and Embodiment 4 and its improved solutions are solutions for reading tags in closed-loop applications. In fact, in order to distinguish whether the reader reads the tag in the open-loop situation or the tag in the closed-loop situation, a mode selection method can be set on the reader to distinguish between open-loop and closed-loop closed loop situation. When the mode selection mode indicates that the reader uses the first mode, the scheme of reading the tag in an open-loop situation is used, that is, the scheme of protecting the length of the EPC code. When the mode selection mode indicates that the reader/writer uses the second mode, the scheme of reading tags in a closed-loop situation is used, that is, the scheme of reading tags when the length of the EPC code is fixed.

Corresponding to the method for protecting the length of the EPC code in Embodiment 1 of the present invention, the present invention also proposes a reader/writer for reading data in a tag in a radio frequency identification system, the reader/writer comprising:

An encoding unit, configured to encode feature description information using an encoding with error correction and error detection capabilities;

a writing unit, configured to write the code into a tag;

a reading unit, configured to read the data in the tag, and receive the encoded feature description information;

a decoding unit, configured to decode the feature description information through the encoding;

The receiving unit is configured to read corresponding data according to the decoded feature description information.

Wherein, the writing unit further includes:

A setting unit, configured to set the length of the protocol control bit PC in the label to the sum of the lengths of the EPC code, the error detection code EDC, and the error correction code ECC, and set it on the reserved bit RFU of the protocol control bit PC a protection mark;

a calculation unit, configured to calculate the error detection code EDC for the protocol control bit PC, and calculate the error correction code ECC for the protocol control bit PC and the error detection code EDC;

A storage unit for storing the error detection code EDC and the error correction code ECC at the beginning of the EPC code.

In addition, the reader also includes a command issuing module, which is used to send a protection label selection command to the label in its read-write area, select the label with a protection mark on the reserved bit RFU in the read-write area, and then follow the The method for protecting the length of the EPC code in the present invention reads the data in the protected tag; or sends an ordinary tag selection command to the tag in its read-write area, and selects the reserved tag in the read-write area The bit RFU has no protection mark on the normal tag, and reads the data in the normal tag without the protection mark according to the normal reading steps.

Corresponding to the method of reading the tag when the length of the EPC code in Embodiment 4 of the present invention is fixed, the present invention proposes another reader/writer for reading the data in the tag in the radio frequency identification system, The reader includes:

An interface unit, configured to define an interface between the reader-writer and the host computer connected to the reader-writer, through which the host computer configures the length of the EPC code as a fixed length;

The storage unit is used to store the length of the EPC code configured by the host in the register of the reader;

The reading unit is used to obtain the length of the EPC code of the tag from the storage of the reader when reading the data in the tag;

The receiving unit is configured to set the data bits to be received and prepare to receive data.

In order to further demonstrate the advantages of the method provided by the present invention, the following tests were carried out. These tests are based on simulating real manufacturing applications with interference sources. The setup made in the test is shown in Figure 16. The two readers in Figure 16 are based on the Indy R1000 platform. In Table 1 the test parameter settings are shown.

Table 1 Measurement parameter settings

The power of the reader to read 20dBm Backscattered power from tag to reader -58dBm Interfering with the power of the reader -45dBm to -30dBm The carrier frequency of the reader to read 915.75MHz Interference with the carrier frequency of the reader 915.75MHz (same channel) error detection code CRC-5 error correction code BCH(31, 21)

A reading reader shall operate according to the link parameters listed in Table 2.

Table 2 Link parameters of the reader for reading

Modulation Tari(us) x Encoding LF(kHz) Data rate (kbps) DSB-ASK 6.25 0.5 FM0 400 400

Figure 17 shows the relationship between BER performance and interference power. From Figure 17 we can see that BER increases rapidly with the increase of interference power. The method of the present invention is generally used at a BER of 0.1 or less. Figure 18 shows the relationship between the RN16 timeout percentage and the interference power. It can be seen from Fig. 18 that there have been many RN16 timeouts in areas with larger BERs.

In order to study the reading speed of a single tag in the normal reading and writing process and the method of the present invention, the time to read a single tag based on these two reading methods will be compared and simulated.

For the normal reading process, equation (1) can be used to calculate the time to read a single tag.

${\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}}<span\; class="notranslate">\; )</span>}^{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="N"\; filenames="H2009101600596E0000012.png"\; state="\{\{state\}\}">N</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}$

${\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; PC</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}}<span\; class="notranslate">\; )</span>}^{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="N"\; filenames="H2009101600596E0000012.png"\; state="\{\{state\}\}">N</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}$

${\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; EPC</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}}<span\; class="notranslate">\; )</span>}^{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="N"\; filenames="H2009101600596E0000142.png,H2009101600596E0000151.png"\; state="\{\{state\}\}">N</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}$

$\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; init</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; EPC\; Retry</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}}<span\; class="notranslate">\; \&times;</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; PC</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; PCRETRY</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; EPC</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; EPCRETRY</span>}}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; PC</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; EPC</span>}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; QueryRep</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Among them, P _b is BER; P _e is the PER of the protocol control bit PC+EPC code + cyclic redundancy check bit CRC16 packet transmission; P _PC is the error probability of the protocol control bit PC; P _EPC is the electronic product code EPC data occurrence Probability of error; T is the time it takes to read a single tag based on the underlying process. In formula (1), there is no limit to the number of ACK retransmissions. T _init and T _EPCRetry are time intervals used in different phases of the protocol in FIG. 19 .

For the solution of the present invention to correctly obtain the EPC code by protecting the protocol control bit PC, encode with CRC-5, BCH (31, 21), and formula (2) can be used to calculate the rate of reading a single tag under the solution of the present invention. time.

${\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; PC</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}}<span\; class="notranslate">\; )</span>}^{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}}<span\; class="notranslate">\; )</span>}^{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="P\; b"\; filenames="H2009101600596E0000142.png,H2009101600596E0000151.png"\; state="\{\{state\}\}">P</figure-callout></span><figure-callout\; id="2"\; label="P\; b"\; filenames="H2009101600596E0000142.png,H2009101600596E0000151.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}^{\mathrm{<span\; class="notranslate">b</span>}}<span\; class="notranslate">\; \&times;</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}}<span\; class="notranslate">\; )</span>}^{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>}$

${\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; EPC</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}}<span\; class="notranslate">\; )</span>}^{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="N"\; filenames="H2009101600596E0000142.png,H2009101600596E0000151.png"\; state="\{\{state\}\}">N</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}$

P _e ＝1-(1-P _PC )(1-P _EPC )

$\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; init</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; EPC\; Retry</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; e</span>}}}<span\; class="notranslate">\; \&times;</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; PC</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; PCRETRY</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; EPC</span>}}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; EPCRETRY</span>}}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; PC</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; EPC</span>}}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; QueryRep</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Among them, _NP is the number of protocol control bits PC, and the meanings of other parts are the same as formula (1).

The time for reading a single tag normally and the time for reading a single tag using the solution of the present invention are compared, and the results are shown in Fig. 20 and Fig. 21 .

According to the simulation results, the following conclusions can be drawn: when the BER is small, the performance of the process of reading tags using the scheme of the present invention is similar to that of the normal process (due to the use of redundant bits, the scheme of the present invention is slightly worse than the normal process) . When the BER is large (BER>=1e-3), the advantages of the process of reading tags using the scheme of the present invention are very significant.

(For example, when BER=0.05, the process of reading tags using the solution of the present invention can save more than half of the reading time). Therefore, the solution of the present invention can effectively solve the problem that the reader/writer performs a cyclic redundancy check (CRC) error.

In addition, in order to evaluate the overall performance of the method provided by the present invention, the method for reading the tag and the energy provided to the tag recorded in the Siemens patent application 200810004983.0 are implemented on the Indy R1000 platform when the EPC code of the present invention is fixed. method, or a combination of methods. Specifically: (1) Normal reading;

(2) read the tag under the fixed situation of the EPC code of the present invention; (3) read the tag under the fixed situation of the EPC code of the present invention, and choose to wait to receive the RN16 period as the enhanced period to provide the tag with Energy; (4) under the fixed situation of adopting EPC code of the present invention, label is read, and selects to wait to receive electronic product code EPC data period to provide energy to label as enhanced period; (5) adopt EPC code of the present invention to fix In this case, the tag is read, and the two periods of waiting to receive RN16 and waiting to receive electronic product code EPC data are selected as the enhanced period to provide energy to the tag. The comparison results of read reliability and read rate of these five methods are shown in Fig. 22 and Fig. 23, respectively. From these two figures it can be seen that:

First, due to the reduction of RN16 timeout, EPC timeout and CRC errors, the success rate of the reader to read tag data is greatly improved. When the interference frequency ranges from -9dBm to -5dBm, compared with the normal reading method, the success ratio of reading 1000 times in the method provided by the present invention is greater than 40%. Especially, when the interference frequency is -9dBm, the success ratio of reading 1000 times using the method provided by the present invention is about 90%, indicating that the reliability of reading is very high. However, the normal reading method has only a 50% success rate of reading 1000 times.

Secondly, the reader can achieve a higher reading speed for reading tags. As shown in Fig. 23, when the interference frequency ranges from -5dBm to -9dBm, the method provided by the present invention can read 25 more tags than the normal reading method. In particular, the reading speed of the method provided by the present invention can reach 100 tags per second, which can meet the requirements of most RFID applications.

Finally, the method provided by the present invention will cause little interference to other devices. The reason is that the reader only increases power for a short time to get better read speed, but its power will immediately return to normal level.

To sum up, the method for protecting the feature description information of tags in the radio frequency identification system provided by the present invention can achieve higher reading speed and higher reliability. According to the measurement results, especially in the noise environment, the reading reliability and speed of the tag can be greatly improved by adopting the present invention. Therefore, this approach is well suited for improving the reliability and efficiency of read/write operations in applications where noisy environments exist, such as manufacturing applications. On the other hand, the implementation of this scheme only needs to modify the firmware of the reader, which is very simple. And, the method is fully compliant with the EPC C1G2 standard, so it can be easily implemented in current tags and readers.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (29)

1. method that in radio-frequency recognition system, the data in the label is read, described radio-frequency recognition system comprises an above read write line and one group of label, described each label all comprises one a group of data and a stack features descriptor, it is characterized in that the method includes the steps of:

(1) first read write line or described label use the coding with error correction and error detecing capability, and described feature description information is encoded and described coding is write described label;

(2) described first read write line or second read write line read described label, receive described feature description information after encoded, and by described coding described feature description information are decoded;

(3) described first read write line or second read write line read corresponding data according to decoded feature description information.

2. a kind of method that in radio-frequency recognition system, the data in the label is read according to claim 1, it is characterized in that: in the described step (1), described coding with error correction and error detecing capability comprises an error-detecting code (EDC) and an error-correcting code (ECC).

3. a kind of method that in radio-frequency recognition system, the data in the label is read according to claim 2, it is characterized in that: the data of described label are the data in electronic product code (EPC) data field, the feature description information of described label is agreement control bit (PC), the length records of the electronic product code (EPC) in described electronic product code (EPC) data field is in described agreement control bit (PC)

In the described step (1), described first read write line uses described error-detecting code (EDC) and described error-correcting code (ECC) that described agreement control bit (PC) is encoded, and described coding is write in described label electronic product code (EPC) data;

In the described step (2), described first read write line or second read write line read the electronic product code in the described label (EPC) data, receive the agreement control bit (PC) behind the described coding, and the agreement control bit (PC) behind the described coding is decoded;

In the described step (3), described first read write line or second read write line according to decoded agreement control bit (PC) will be to be received data bit be provided with and prepare to receive data.

4. a kind of method that in radio-frequency recognition system the data in the label is read according to claim 3 is characterized in that: comprise following steps in the described step (1):

(11) length that write down of described agreement control bit (PC) is set to the length sum of described electronic product code (EPC), error-detecting code (EDC), error-correcting code (ECC);

(12) a protection sign is set on the reserved bit (RFU) of described agreement control bit (PC);

(13) calculate described error-detecting code (EDC) for described agreement control bit (PC);

(14) calculate described error-correcting code (ECC) for described agreement control bit (PC) and described error-detecting code (EDC);

(15) described error-detecting code (EDC) and described error-correcting code (ECC) are stored into the starting position of described electronic product code (EPC).

5. a kind of method that in radio-frequency recognition system, the data in the label is read according to claim 3, it is characterized in that: in the described step (2), described first read write line or second read write line agreement control bit (PC) after with described coding is decoded and is further comprised:

Described first read write line or second read write line carry out error-detecting and correction by described error-correcting code (ECC) to described agreement control bit (PC) and described error-detecting code (EDC);

Described first read write line or second read write line carry out error-detecting by described error-detecting code (EDC) to described agreement control bit (PC), to obtain the length of correct electronic product code (EPC).

6. a kind of method that in radio-frequency recognition system, the data in the label is read according to claim 5, it is characterized in that: wrong if described error-detecting code (EDC) detects described agreement control bit (PC), the length of the electronic product code (EPC) that the described pickup of then described first read write line or second read write line is received is set to the length of the electronic product code (EPC) of previous label.

7. a kind of method that in radio-frequency recognition system, the data in the label is read according to claim 5, it is characterized in that: wrong if described error-detecting code (EDC) detects described agreement control bit (PC), the length of the electronic product code (EPC) of then described first read write line or the described reception of second read write line is set to 96 bits.

8. a kind of method that in radio-frequency recognition system, the data in the label is read according to claim 5, it is characterized in that: wrong if described error-detecting code (EDC) detects described agreement control bit (PC), then described first read write line or second read write line at first wait the longest described electronic product code to be read (EPC) required time, start a new label subsequently and read process.

9. a kind of method that in radio-frequency recognition system the data in the label is read according to claim 8, it is characterized in that: the longest described electronic product code (EPC) is 496 bits.

10. a kind of method that in radio-frequency recognition system, the data in the label is read according to claim 3, it is characterized in that: in the described step (3), the length that the data bit that described first read write line or second read write line will receive is set to described electronic product code (EPC) adds 32 bits.

11. a kind of method that in radio-frequency recognition system, the data in the label is read according to claim 3, it is characterized in that: if the length of described electronic product code (EPC) changes, then described first read write line writes described error-detecting code (EDC) and described error-correcting code (ECC) in the described electronic product code data once more.

12. a kind of method that in radio-frequency recognition system the data in the label is read according to claim 3 is characterized in that: described step (1) is before, and is further comprising the steps of:

Described first read write line or second read write line send a protection label select command to being in its label of reading and writing in the zone, are chosen in the label that the interior reserved bit (RFU) in described read-write zone is provided with described protection sign.

13. a kind of method that in radio-frequency recognition system the data in the label is read according to claim 12 is characterized in that: described step (3) also comprises afterwards:

Described first read write line or second read write line label in being in its read-write zone sends a common label select command; be chosen in the common label that described protection sign is not set on the reserved bit (RFU) in the described read-write zone, and the data in the described common label that described protection sign is not set read according to common read step.

14. a kind of method that in radio-frequency recognition system, the data in the label is read according to claim 3, it is characterized in that: also comprise before: a model selection mode is set in described first read write line or second read write line in described step (1), when described read write line is chosen described model selection mode, begin described step (1).

15. according to claim 3 or 4 described a kind of methods that in radio-frequency recognition system, the data in the label read, it is characterized in that: described first read write line or second read write line select to wait for that receiving the RN16 period receives electronic product code (EPC) data at least one period in the period as strengthening the period with waiting for, described read write line is regulated sending the gain of signal, makes that the carrier signal in the described enhancing period sends with the transmitted power that strengthens.

16. a kind of method that in radio-frequency recognition system, the data in the label is read according to claim 2, it is characterized in that: the data of described label comprise data in electronic product code (EPC) data field and the data in the user data area, the feature description information of described label is agreement control bit (PC), in the described user data area of described agreement control bit (PC) sign whether valid data are arranged

In the described step (1), described first read write line uses described error-detecting code (EDC) and described error-correcting code (ECC) that described agreement control bit (PC) is encoded, and described coding is write in described label electronic product code (EPC) data;

In the described step (2), described first read write line or second read write line read the electronic product code in the described label (EPC) data, receive the agreement control bit (PC) behind the described coding, and the agreement control bit (PC) behind the described coding is decoded;

In the described step (3), described first read write line or second read write line determine whether initiate data read command according to decoded agreement control bit (PC), and the data in the described user data area are read.

17. a kind of method that in radio-frequency recognition system the data in the label is read according to claim 16 is characterized in that: comprise following steps in the described step (1):

(11) length that write down of described agreement control bit (PC) is set to the length sum of described electronic product code (EPC), error-detecting code (EDC), error-correcting code (ECC);

(12) a protection sign is set on the reserved bit (RFU) of described agreement control bit (PC);

(13) calculate described error-detecting code (EDC) for described agreement control bit (PC);

(14) calculate described error-correcting code (ECC) for described agreement control bit (PC) and described error-detecting code (EDC);

(15) described error-detecting code (EDC) and described error-correcting code (ECC) are stored into the starting position of described electronic product code (EPC).

18. a kind of method that in radio-frequency recognition system, the data in the label is read according to claim 2, it is characterized in that: the data of described label comprise data in electronic product code (EPC) data field and the data in the user data area, the feature description information of described label is agreement control bit (PC) and Extended Protocol control bit (XPC), recalled state after the described label of sign is killed in the described Extended Protocol control bit (XPC)

In the described step (1), described first read write line uses described error-detecting code (EDC) and described error-correcting code (ECC) that described agreement control bit (PC) and described Extended Protocol control bit (XPC) are encoded, and described coding is write in the described label;

In the described step (2), described first read write line or second read write line read described label, receive agreement control bit (PC) and Extended Protocol control bit (XPC) behind the described coding, and agreement control bit (PC) behind the described coding and Extended Protocol control bit (XPC) are decoded;

In the described step (3), described first read write line or second read write line are according to the recalled state of decoded agreement control bit (PC) and Extended Protocol control bit (XPC) decision label.

19. a kind of method that in radio-frequency recognition system the data in the label is read according to claim 18 is characterized in that: described step may further comprise the steps in (1):

(11) length that write down of described agreement control bit (PC) is set to the length sum of described electronic product code (EPC), error-detecting code (EDC), error-correcting code (ECC);

(12) a protection sign is set on the reserved bit (RFU) of described agreement control bit (PC);

(13) calculate described error-detecting code (EDC) for described agreement control bit (PC);

(14) calculate described error-correcting code (ECC) for described agreement control bit (PC) and described error-detecting code (EDC);

(15) described error-detecting code (EDC) and described error-correcting code (ECC) are stored in the described label.

20. a kind of method that in radio-frequency recognition system, the data in the label is read according to claim 19, it is characterized in that: in the described step (15), described error-detecting code (EDC) and described error-correcting code (ECC) are stored into the starting position of described electronic product code (EPC).

21. a kind of method that in radio-frequency recognition system, the data in the label is read according to claim 19, it is characterized in that: in the described step (15), described error-detecting code (EDC) and described error-correcting code (ECC) are stored in the described Extended Protocol control bit (XPC).

22. method that in radio-frequency recognition system, the data in the label is read, described radio-frequency recognition system comprises an above read write line and one group of label, described each label all comprises the data in electronic product code (EPC) data field, each described electronic product code (EPC) data comprises agreement control bit (PC), electronic product code (EPC), cyclic redundancy check (CRC) position (CRC), it is characterized in that the method includes the steps of:

(1) read write line and with main frame that described read write line links to each other between interface of definition, by the described main frame of described interface the length of described electronic product code (EPC) is configured to a regular length;

(2) described read write line is stored the length of the electronic product code (EPC) that described main frame disposed in its register;

When (3) described read write line reads the data in the described label, from the register of this read write line, obtain the length of the electronic product code (EPC) of described label;

(4) data bit that described read write line will be to be received is provided with and prepares to receive data.

23. a kind of method that in radio-frequency recognition system, the data in the label is read according to claim 22, it is characterized in that: in the described step (4), the length that the data bit that the described read write line or second read write line will receive is set to described electronic product code (EPC) adds 32 bits.

24. according to claim 22 or 23 described a kind of methods that in radio-frequency recognition system, the data in the label read, it is characterized in that: also comprise before: a model selection mode is set in described first read write line or second read write line in described step (1), when described read write line is chosen described model selection mode, begin described step (1).

25. according to claim 22 or 23 described a kind of methods that in radio-frequency recognition system, the data in the label read, it is characterized in that: described read write line selects to wait for that receiving the RN16 period receives electronic product code (EPC) data at least one period in the period as strengthening the period with waiting for, described read write line is regulated sending the gain of signal, makes that the carrier signal in the described enhancing period sends with the transmitted power that strengthens.

26. a read write line that in radio-frequency recognition system the data in the label is read is characterized in that, described read write line comprises:

Coding unit is used to use a coding with error correction and error detecing capability that feature description information is encoded;

Writing unit is used for described coding is write a label;

Reading unit is used for the data of described label are read, and receives described feature description information after encoded;

Decoding unit is used for by described coding described feature description information being decoded;

Receiving element is used for according to decoded feature description information corresponding data being read.

27. a kind of read write line that in radio-frequency recognition system the data in the label is read according to claim 26, it is characterized in that: the said write unit further comprises:

The unit is set, the length that is used for described label agreement control bit (PC) is set to the length sum of electronic product code (EPC), error-detecting code (EDC), error-correcting code (ECC), and a protection sign is set on the reserved bit (RFU) of described agreement control bit (PC);

Computing unit is used to described agreement control bit (PC) to calculate described error-detecting code (EDC), and is that described agreement control bit (PC) calculates described error-correcting code (ECC) with described error-detecting code (EDC);

Storage unit is used for described error-detecting code (EDC) and described error-correcting code (ECC) are stored into the starting end of described electronic product code (EPC).

28. a kind of read write line that in radio-frequency recognition system, the data in the label is read according to claim 27, it is characterized in that: described read write line comprises that also an order sends module, be used for sending a protection label select command, be chosen in the label that the interior reserved bit (RFU) in described read-write zone is provided with described protection sign to being in its label of reading and writing in the zone; Perhaps the label in being in its read-write zone sends a common label select command; be chosen in the common label that described protection sign is not set on the reserved bit (RFU) in the described read-write zone, and the data in the described common label that described protection sign is not set read according to common read step.

29. a read write line that in radio-frequency recognition system the data in the label is read is characterized in that, described read write line comprises:

Interface unit, be used for read write line and with main frame that described read write line links to each other between interface of definition, by the described main frame of described interface the length of described electronic product code (EPC) is configured to a regular length;

Storage unit is used for the length at the register storage electronic product code (EPC) that described main frame disposed of described read write line;

Reading unit is used for when the data to described label read, and obtains the length of the electronic product code (EPC) of described label from the depositing of this read write line;

Receiving element is used for data bit to be received is provided with and prepares to receive data.

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