KR100623066B1 - Rfid tag information anti-collision apparatus using pre-distributed random address and the method of it - Google Patents

Abstract

The present invention provides an RFID tag information collision prevention apparatus and method using pre-distributed random numbers to prevent data collision between tags by using random numbers pre-distributed to a radio frequency identification (RFID) tag.

The RFID tag for the tag information collision avoidance apparatus of the present invention includes a first storage area for storing a random address type route address to be used as an address for the tag, a unique number of the product, and a product serial number; And a second storage area for storing a slave address for collision processing when a collision between a primary address and tag information initialized by the root address occurs, and the reader receives tag data based on the primary address and collides during data reception. And a collision processing unit for increasing the slave address every occurrence and decreasing the slave address upon completion of data reception. The present invention not only does not require an RNG in a tag, but also minimizes waste of time and retransmission. Compared to the tree traversal technique, it can show faster performance and guarantee stable processing at predictable time even if the number of tags is greatly increased.

RFID, Anti-collision Algorithm, Random Numbers, Tags, Readers

Description

RDF tag information collision prevention apparatus and method using pre-distributed random number {RFID TAG INFORMATION

1 is a schematic configuration diagram of an RFID tag information collision avoidance apparatus using pre-distributed random numbers according to the present invention.

2a and 2b is a detailed configuration of the present invention.

3 illustrates a data field of the RFID tag of FIG.

4 is an operational flowchart of the present invention.

5 is a schematic diagram of a tag data collection process using a primary address calling query in the present invention.

6 is an exemplary operation tag according to the present invention.

Fig. 7 is an explanatory diagram of use of part of a serial number as a root address in the present invention.

<Explanation of symbols for the main parts of the drawings>

100: RFID tag 110, 120: first, second memory

130: antenna 200: reader

210: collision processing unit 220: transmitter

230: receiver 240: power unit

The present invention relates to a radio frequency identification (RFID) system, and more particularly, to an RFID tag information collision avoidance apparatus and method using pre-distributed random numbers to prevent data collision between tags by using random numbers pre-distributed to a tag. It is about.

RFID is a field of automatic recognition such as barcode, magnetic, IC card, etc., and is a state-of-the-art method of wirelessly recognizing information recorded using microwave or long wave.

The principle of the RFID system is to receive information stored in a tag through an antenna, and to recognize and analyze the reader so as to acquire the unique information of the tag-mounted article, which uses the frequency of snow, rain, and wind. It is not affected by the environment such as dust, magnetic flux, and has the advantage of being able to be recognized on the move due to the fast passing speed.

Such RFID systems are applied to supermarkets, parking management, and the like. For example, in the case of a supermarket, if a tag having a unique information is recorded on a sale item, a computer connected to the reader is used to display the current shelf using the information received through the tag. The remaining quantity of goods can be identified automatically, and information about the purchased goods can be easily collected even if the consumer does not calculate separately.

The RFID system is composed of a tag and a reader. The tag is equipped with a memory for storing unique information and an antenna for communication, and is activated when the reader receives power from the reader in proximity to the reader. When the tag is activated, the reader transmits its information to the reader. The tag information can be recognized.

The greatest strength of such an RFID system is that the memory of each tag can hold the author information for each product. Existing barcode system is used only for product recognition by providing unique number for each variety, but tag can provide different number for each product instead of variety, so that each product can contain unique information. .

In this RFID system, the anti-collision algorithm is the dominant performance of the air interface.

Anti-collision algorithms include Aloha-based algorithms that transmit data at a desired time along the time axis, and binary tree-based algorithms that use binaryity, where the data of tags consists of zeros and ones. .

Aloha-based collision avoidance requires that all tags compete to send data to the reader. The reason why the tag is difficult to check the status of the media is that the RFID system divides the time into slots (or frames) and transmits the data at the synchronized time.

The advantage of this method is that high data rates under deterministic transmission are ensured by transmitting the tag's data continuously. On the other hand, the disadvantage is found in situations where the number of tags is unpredictable. If the number of tags is small, Aloha-based algorithms waste slots. On the contrary, if the number of tags is too large, the slots required for recognition may explode due to the collision caused by the competition of the tags, and in a serious case, even one of the tag information may not be recognized even if the time increases indefinitely.

In addition, it is inevitable to use a random number generator (RNG) to determine when a tag sends data to the reader.

In the RFID system using binary tree search based collision avoidance, the reader reads the information of the tag one bit. The reader controls the tag by sending commands such as "next bit" or "who is x" to the tag.

As a result, the reader navigates through the tag's information as if it were searching the tree. The advantage of this method is found in deterministic data transfer.

Since the reader will use all the data sent by the tag, it is as if there is no unnecessary disappearance due to the collision. In addition, even if there are a large number of tags or a small number of tags, the overall performance can be predicted in a linear equation.

On the other hand, the disadvantage is that the reader must send the tag as many command queries as the data the tag sends to the reader. In addition, the tag has a disadvantage that the process of charging and discharging the power in order to send data to the reader is too frequent.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and an object of the present invention is to prevent collision of RFID tag information using pre-distributed random numbers, which can improve collision prevention performance by preventing data collision between tags using random numbers previously distributed to tags. An apparatus and a method thereof are provided.

In order to achieve the object of the present invention, an RFID tag information collision prevention apparatus using a random number distributed in advance according to the present invention is a data collision prevention apparatus between a contactless reader and a plurality of RFID tags, wherein the RFID tag is associated with the tag. A first storage area for storing a random address type root address to be used as an address, a unique number of the product, and a product serial number; A second storage area for storing a primary address initialized by the root address when the RFID tag is activated and a slave address for collision processing when a collision of tag information occurs; and the reader stores tag data based on the primary address. And a conflict processing unit which increases the slave address every time a collision occurs during data reception and decreases the slave address when data reception is completed.

RFID tag information collision prevention method using a random number distributed in advance according to the present invention for achieving the object of the present invention, a contactless reader having a collision processing unit for preventing data collision; Conflict between the primary address and tag information initialized by the root address when activated by the reader and a nonvolatile memory area in which a random number root address to be used as an address for the tag and a product unique number and product serial number are stored. A method of preventing data collision between RFID tags having a volatile memory area in which a slave address for collision processing is generated, when the RFID tag is activated by the reader, a value of a root address stored in the nonvolatile memory area is converted into a volatile memory. Moving to a primary address of an area and initializing the slave address; A second step of the reader reading the primary addresses of the RFID tags; A third step in which the reader selects RFID tags while sequentially calling a primary address using a primary address calling query and receives data of the selected RFID tag; If a collision occurs during the data transmission by using a spreading through the increase and decrease of the slave address located in the volatile memory area of the RFID tag, the fourth step of entering the parking mode when the RFID tag is completed; includes; Characterized in that.

The slave address decreases according to the slave address calling query of the reader, and increases according to the slave address allocation query, and when the RFID tag enters the parking mode, it changes its primary address to change its primary address into an available address space. The RFID tag is assigned to the reader, and the RFID tag attempts transmission only when its primary address is called and the slave address is 0.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the following examples are merely to illustrate the present invention is not limited to the contents of the present invention.

1 illustrates an RFID tag data collision prevention apparatus using a random number distributed in advance according to the present invention, and is largely composed of a plurality of RFID tags 100 and a contactless reader 200.

As shown in FIG. 2A, the RFID tag 100 stores a root address, a product number, and a product serial number in the form of a random number to be used as an address for the tag. Second memory 120 and reader 200 in which a first address 110, a primary address initialized by the root address, and a slave address for collision processing when a collision of tag information occurs are stored. Antenna 130 for communication with). The first memory 110 is a ROM, which is a nonvolatile memory, and the second memory 120 is a RAM, which is a volatile memory.

As shown in FIG. 2B, the reader 200 receives tag data based on the primary address, increases the slave address whenever a collision occurs during data reception, and decreases the slave address when data reception is completed. The processor 210 includes a transmitter 220, a receiver 230, and a power supply 240 for data transmission and reception with the RFID tag 100.

3 illustrates a data field of the RFID tag 100. The root address stored in the first memory 110, which is a nonvolatile memory, is a random number previously distributed by a tag manufacturer, and a product number and a product serial number. It is also given according to the product by the tag manufacturer.

The primary address stored in the second memory 120, which is a volatile memory, occupies a memory area of the same size as the root address, and the slave address occupies a memory area of a size smaller than the primary address.

The present invention configured as described above will be described with the flowchart of FIG.

First, when the RFID tag 100 is activated by the reader 200, the RFID tag 100 moves a value in a root address stored in the first memory 110 to a primary address. At the same time, the slave address of the RFID tag 100 is initialized to 0 (S110).

Thereafter, the collision processing unit 210 of the reader 200 reads the primary addresses of the RFID tags 100 through the receiver 220 using a binary tree search method (S120). In this case, the reader 200 continuously supplies power to the RFID tag 100 so that data updated in the second memory 120 of the RFID tag 100 is preserved.

When the reader 100 reads out the primary address, the RFID 100 is selected by sequentially calling the primary address using a primary address calling query and repeating block transmission. Receive the data of (S130).

5 is a schematic diagram of a tag data collection process using a primary address calling query, wherein the collision processing unit 210 of the reader 200 includes primary addresses of RFID tags 100 obtained by using a binary tree detection scheme. By transmitting the primary address calling query, data may be received from the RFID tags 100 having a specific primary address.

When all the data for the RFID tags 100 having one primary address are transmitted, the primary address calling query is transmitted again to receive the data of the tags having different primary addresses. When receiving data, the reader 200 and the RFID tag 100 transmit data in units of promised blocks. The delay between blocks is generally a little longer than the delay that occurs when exchanging messages between the RFID tag 100 and the reader 200.

In FIG. 5, the IBT is an inter-bit time, and when the data is changed from the reader 200 to the RFID tag 100 or the RFID tag 100 to the reader 200, the RFID tag 100 is changed. Or BT 200, which is necessary for the processing delay time required for the reader and the stability of data recognition, and the time between the BT and the BT.

Meanwhile, the collision occurring during the block transmission is solved using spreading, and the RFID tag 100 enters the parking mode after transmitting all the data (S140-S170).

Spreading is a process of allocating a new record from the time of collision (increasing slave address), and returning to an existing record (reducing slave address) if all data has been transmitted safely.

Parking is the process of automatically converting a primary address into a pre-reserved "absolutely never called" address (e.g. 0x00) when it confirms that all data has been transmitted securely and assigns it to another tag for use. to be.

That is, the present invention performs collision processing while increasing or decreasing the slave address based on the primary address.

The RFID tags 100 whose primary addresses are called except for the RFID tags 100 corresponding to specific bits of the position indicated by the reader 200 increase the slave address value whenever a collision occurs. The RFID tag 100 basically attempts data transmission only when the primary address is called and the slave address is "0x00".

Here, attempting data transmission only when the slave address is "0x00" means that the slave address is initialized to 0x00, and then the increment and decrement are repeated by the query of the reader 200. This is because it only needs to be sent when the slave address is 0x00.

When all data of the RFID tag 100 is transmitted, the reader 200 commands to decrease the slave address. When all the RFID tags 100 complete the transmission at the primary address, the reader 200 calls another main address and repeats the above process.

This will be described with reference to FIG. 6.

FIG. 6 shows an example of operation of three FRID tags 100 having addresses 1011 0111 (0x02), 1101 0101 (0x02), and 1011 0101 (0x03) (indicated in parentheses). ) Has previously used 0x02 and 0x03 as primary addresses using binary tree traversal.

The reader 200 sends a primary address calling query for 0x02 (PC2). The 1011 0111 and 1101 0101 RFID tag 100 then collide in the second bit of the first block and the reader 200 knows this.

The reader 200 transmits a slave address allocating query for the second bit (SA2). Then, the RFID tag 100 whose second bit is 0 increases the slave address by one.

The RFID tag 100 having the second bit 1 starts transmission again from the third bit and ends the transmission until the next block. If transmission is completed for one RFID tag 100, the reader 200 transmits a slave address calling query (SC).

Upon receiving this message, the RFID tag 100 decreases the slave address by 1 and resumes transmission after the bit that previously stopped transmission. When all transmissions for the primary address 0x02 are completed, the reader 200 transmits the primary address calling query for 0x03 to receive data for the remaining RFID tag 100.

If the spreading count is greater than the maximum value of the slave address and no longer spreadable, an empty primary address is allocated, and the slave addresses of the RFID tags 100 to which the new primary address is allocated are “0x0”. Spreading continues by initializing

If there is no empty primary address, the reader 200 expects to generate an empty primary address by calling another primary address. At the time when the empty primary address occurs, the reader 200 may continue the previous spreading.

In addition, in order to reduce the data transmitted by the RFID tag 100, the tag manufacturer may use the serial number portion of the RFID tag 100 as a root address, as shown in FIG. In this process, if the reader 200 knows that the RFID tag 100 uses its serial number as its root address, the reader 200 negotiates the size of the root address with the RFID tag 100 beforehand. Can be.

Meanwhile, in the present invention, the primary address calling query is composed of flag + primary address, the primary address allocation query is composed of flag + collision bit position + new primary address, and the slave address calling query is composed only of flags. The slave address assignment query consists of the flag + conflict bits.

The present invention as described above does not include the RNG that can be a burden on the RFID tag 100, instead of a plurality of RFID tags 100 while the reader 200 controls the address pre-distributed to the RFID tag 100 In the manner that the reader 200 reads the information of the RFID tag 100, the RFID tag 100 must include a random number uniformly assigned by the tag manufacturer in advance and can use it as its primary address or treat it as its own random number. The available part should be available as the primary address.

In addition, the reader 200 calls the primary address of the RFID tag 100 in order to adjust the state of the RFID tag 100 and receives data transmission in units of blocks. With respect to a collision occurring during block transmission, the reader 200 may control the slave address so as to efficiently retransmit the block in which the collision occurred, thereby reducing the probability of a collision occurring later.

After the RFID tag 100 transmits all data, the RFID tag 100 changes its primary address to a parking address so that the reader 200 can reuse the primary address later.

In addition, system administrators and tag manufacturers can build systems with performance and stability that are appropriate for them by adjusting the size of the primary address and the slave address. For example, when a 10-bit primary address and a 5-bit slave address are used, about 32,768 tags can be processed.

 As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art various modifications of the present invention without departing from the spirit and scope of the invention described in the claims below Or it may be modified.

As described above, the present invention can avoid collision of the tag by using a randomly distributed random number as an address, thus not only needing the RNG in the RFID tag, but also minimizing the waste of time and retransmission and searching the existing binary tree. The performance is much faster than that of the technique, and even if the number of tags is greatly increased, a stable processing can be guaranteed at a predictable time.

Claims (10)

In the device for preventing data collision between a contactless reader and a plurality of RFID tags, The RFID tag is A first storage area storing a random address type root address to be used as an address for the tag, a unique number of the product, and a product serial number; And a second storage area storing a slave address for collision processing when a collision between a primary address and tag information initialized by the root address when RFID tag is activated, The leader A collision processing unit which accepts tag data based on the primary address, increases the slave address whenever a collision occurs during data reception, and decreases the slave address when data reception is completed; RFID tag information collision avoidance apparatus using a randomly distributed random number characterized in that it comprises a. 2. The apparatus of claim 1, wherein the first storage area is a nonvolatile memory and the second storage area is a volatile memory. 2. The apparatus of claim 1, wherein the root address is assigned by a tag manufacturer. 2. The apparatus of claim 1, wherein the product serial number is reusable as a root address. A contactless reader having a collision processing unit for data collision prevention; Conflict between the primary address and tag information initialized by the root address when activated by the reader and a nonvolatile memory area in which a random number root address to be used as an address for the tag, a unique number of the product, and a product serial number are stored. A data collision prevention method between RFID tags having a volatile memory area in which a slave address for collision processing is stored when there is a problem, A first step of initializing the slave address by moving a value of a root address stored in the nonvolatile memory area to a primary address of a volatile memory area when the RFID tag is activated by the reader; A second step of the reader reading the primary addresses of the RFID tags; A third step in which the reader selects RFID tags while sequentially calling a primary address using a primary address calling query and receives data of the selected RFID tag; A fourth step of solving the collision by spreading the slave address located in the volatile memory area of the RFID tag when the collision occurs, and entering the parking mode when the data transfer is completed; RFID tag information collision prevention method using a pre-distributed random number comprising a. 6. The method of claim 5, wherein the slave address decreases according to a slave address calling query of a reader and increases according to a slave address allocation query. 6. The RFID tag information of claim 5, wherein the RFID tag changes its primary address and assigns its primary address to the reader in an available address space when entering the parking mode. How to avoid collisions. 6. The method of claim 5, wherein the RFID tag attempts transmission only when its primary address is called and the slave address is 0. In the RFID tag for preventing data collision between a contactless reader and a plurality of RFID tags, The RFID tag is A first storage area storing a random address type root address to be used as an address for the tag, a unique number of the product, and a product serial number; And A second storage area storing a slave address for collision processing when a collision between a primary address and tag information initialized by the root address when RFID tag is activated; RFID tag comprising a. Root address in random form to be used as the address for the tag, product unique number and product serial number, and slave address for conflict processing when collision of primary address and tag information initialized by the route address when RFID tag is activated In the non-contact reader for preventing data collision between RFID tags having a, The leader A collision processing unit which accepts tag data based on the primary address, increases the slave address whenever a collision occurs during data reception, and decreases the slave address when data reception is completed; Contactless reader for preventing RFID tag information collision, characterized in that it comprises a.

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