Method for dynamically adjusting coding range of ultrahigh-frequency RFID (Radio Frequency Identification Device) tag

Abstract

The invention provides a method for dynamically adjusting a coding range of an ultrahigh-frequency RFID (Radio Frequency Identification) tag, which is characterized by comprising the following steps: a communication link between a reader-writer and the tag enters a dynamic adjustment stage according to a preset strategy, and after the dynamic adjustment stage is completed, coding operation of the tag is executed; the preset strategy is that stable one-to-one communication connection is established between the reader-writer and the tag; or after the communication connection is established, executing the code writing operation when the current tag moves to the radiation range boundary point of the current antenna; in the dynamic adjustment stage, the adjustment scheme is that the transmitting power of the reader-writer is dynamically adjusted or the radio frequency port connected with the large-radiation-range antenna is switched. According to the invention, the label can be ensured to be always in the effective communication range of the reader-writer in the whole coding process, so that the coding failure caused by the fact that the label exceeds the range is avoided, the coding efficiency is remarkably improved, the coding success rate of the motion label is greatly improved, and the method is suitable for various scenes in which the motion label needs to be coded.

Description

Technical Field

[0001] The present invention relates to the technical field of RFID tags, and particularly to a method for dynamically adjusting the coding range of ultra-high frequency RFID tags. Background Art

[0002] Radio Frequency Identification (RFID) technology is a non-contact automatic identification technology. It automatically identifies target objects through radio frequency signals and obtains relevant data. The identification work does not require manual intervention and can work in various harsh environments. An RFID system mainly consists of three parts: a reader, an electronic tag, and an antenna. Among them, the reader is used to read or write tag information, the electronic tag serves as the identifier of the object to be identified, and the antenna transmits radio frequency signals between the tag and the reader.

[0003] In the existing RFID tag coding process, the reader usually maintains a constant transmission power and radio frequency port throughout the inventory cycle. Although this fixed working mode can meet the basic requirements in some static or low-speed movement scenarios, it has obvious limitations when facing high-speed moving tags.

[0004] When it is necessary to code a specific tag among multiple moving tags, a near-field antenna is generally used for reading and writing operations. However, the coding process takes a certain amount of time, usually between more than ten milliseconds and dozens of milliseconds. Since the tag is in a high-speed movement state, within this short coding time, the tag is very likely to exceed the reading and writing range of the near-field antenna, resulting in coding failure. In practical applications, especially in fields with high requirements for dynamic identification such as logistics, warehousing, and transportation, this situation seriously affects the efficiency and reliability of the RFID system.

[0005] In addition, the existing RFID systems lack flexibility and adaptability when facing tags in different scenarios and with different moving speeds. For example, in some logistics scenarios where a large number of high-speed moving goods need to be quickly inventoried and information updated, the traditional method with a fixed coding range cannot meet the requirements of efficient and accurate coding; in the transportation field, when coding the RFID tags on high-speed moving vehicles, similar challenges are also faced.

[0006] Therefore, how to dynamically adjust the coding range according to the movement state of the tag and the specific scenario requirements during the RFID tag coding process to improve the coding efficiency and success rate has become an urgent problem to be solved in the current RFID technology field. Summary of the Invention

[0007] Objective of the Invention: The objective of the present invention is to provide a method for dynamically adjusting the coding range of ultra-high frequency RFID tags to improve the coding efficiency and success rate in view of the deficiencies of the prior art.

[0008] The technical solution provided by the present invention is as follows: A method for dynamically adjusting the coding range of ultra-high frequency RFID tags, characterized by comprising the following steps: The communication link between the reader and the tag enters the dynamic adjustment stage according to a preset strategy, and after the completion of the dynamic adjustment stage, the coding operation of the tag is executed. The preset strategy is as follows: after the reader and the tag establish a stable one-to-one communication connection; or after establishing the communication connection and performing the coding operation, when the current tag moves to the boundary point of the radiation range of the current antenna. In the dynamic adjustment stage, the adjustment scheme is: dynamically adjusting the transmission power of the reader or switching the RF port connected to the antenna with a large radiation range.

[0009] A further limitation of the technical solution of the present invention is that the method for determining that the tag moves to the boundary point of the radiation range of the current antenna is: after the current tag moves to the reading and writing range of the reader for a time T1, it reaches the boundary point of the radiation range of the current antenna; where the time T1 = S1 / V, S1 is the effective reading and writing range length of the current antenna, and V is the running speed of the tag.

[0010] Furthermore, the method for switching the RF port connected to the antenna with a large radiation range is: in the case where the reader is equipped with multiple RF ports, switch to the RF port connected to the antenna with a large radiation range according to the position of the tag to expand the coding range; multiple antenna ports usually use an RF switch to achieve port switching, and the main control chip configures the RF switch to achieve antenna port switching.

[0011] Furthermore, when switching to the RF port connected to the antenna with a large radiation range, the channel selection methods are: (1) switching between two channels and two antennas; (2) switching between multiple channels and multiple antennas; (3) not switching the antenna and adjusting the transmission power of the antenna. (4) For multiple channels and multiple antennas, enable multiple antennas to work simultaneously.

[0012] Furthermore, in the dynamic adjustment stage, the dynamic control adopts any one of the following methods: (1) writing the control logic into the reader internally, and the reader controls itself; (2) controlling through an external system, such as a computer or an industrial control computer.

[0013] A system for implementing the above-mentioned dynamic adjustment of the coding range of ultra-high frequency RFID tags provided by the present invention includes a reader, an antenna connected to the reader, and a sensor. The antenna is used to communicate with the RFID tag, and the sensor is used to detect the position of the tag and send a trigger signal to the reader.

[0014] Further limitation of this technical solution is that there are two antennas, namely antenna 1 for establishing a one-to-one communication connection with the RFID tag and antenna 2 for performing the encoding operation of the tag. The radiation range of antenna 2 is greater than that of antenna 1.

[0015] Furthermore, the position where antenna 1 is set ensures that when the tag is at a certain position, the reader can only read this tag.

[0016] Furthermore, the sensor is a physical sensor or a trigger signal given by other devices or a communication instruction given by the host.

[0017] Beneficial effects: By dynamically adjusting the encoding range of the ultra-high frequency RFID tag and dynamically adjusting the transmission power or switching the RF port, the present invention can ensure that the tag is always within the effective communication range of the reader during the entire encoding process, thus avoiding encoding failures caused by the tag exceeding the range, significantly improving the encoding efficiency, greatly increasing the encoding success rate of moving tags, being applicable to various scenarios where encoding of moving tags is required, and having a wide application prospect. By flexibly adjusting the transmission power and RF port, the present invention can dynamically optimize the encoding range according to different tag moving speeds and scenario requirements, enabling the system to better adapt to various complex application scenarios, such as high-speed moving tag identification and information update in the fields of logistics, warehousing, transportation, etc. Description of the Drawings

[0018] Figure 1 is a flowchart of a method for dynamically adjusting the encoding range of an ultra-high frequency RFID tag provided by the present invention. Detailed Embodiments

[0019] The technical solution of the present invention will be described in detail below with reference to the drawings, but the protection scope of the present invention is not limited to the embodiments.

[0020] Embodiment 1 A system for dynamically adjusting the encoding range of an ultra-high frequency RFID tag includes a reader, an antenna connected to the reader, and a sensor. The antenna is used for communicating with the RFID tag, and the sensor is used for detecting the position of the tag and sending a trigger signal to the reader. It is mainly applied to inventory taking. During the inventory taking process, after the reader and the tag establish a stable one-to-one communication connection, it enters the dynamic adjustment stage, switches the RF port connected to the antenna with a large radiation range, and then performs the encoding operation of the tag.

[0021] In this embodiment, when switching to the RF port connected to the antenna with a large radiation range, the channel selection method is as follows: two channels and two antennas are switched. There are 2 antennas and 2 sensors. The antennas are respectively antenna 1 for establishing a one-to-one communication connection with the RFID tag and antenna 2 for performing the write code operation of the tag. The radiation range of antenna 2 is greater than that of antenna 1. Sensor 1 and sensor 2 are respectively arranged in a matching manner with antenna 1 and antenna 2. The position where antenna 1 is arranged ensures that when the tag is at a certain position, the reader can only read this tag. The sensor is a physical sensor or a trigger signal given by other devices or a communication instruction given by the host, etc. The main purpose is to inform the tag to enter the antenna coverage range and make the reader start working. The working principle diagram is as Figure 1 shown, and the specific work is as follows.

[0022] 1. Preparation stage The reader is connected to antenna 1 and the appropriate transmission power is adjusted. The distance between antenna 1 and the tag to be read and written is adjusted so that when the tag is at a certain position, the reader can only read this tag and cannot read other tags. Sensor 1 is set at this position. When the tag reaches this position, sensor 1 sends a trigger signal to the reader to establish communication. Usually, this stage takes about 1 - 3 milliseconds. Ensure that during this stage, the current tag does not leave the coverage range of antenna 1.

[0023] A single tag to be written is placed under antenna 1. The transmission power of RF port 1 connected to antenna 1 is adjusted to W1 so that antenna 1 can only read the current tag. The tag is moved and the reading and writing range length of antenna 1 at power W1 is measured as S1. The write tag program is executed to write all the content to be written into the tag, and the time T1 used for the entire process of writing the tag is recorded.

[0024] The position of antenna 2 is adjusted, and the transmission power of RF port 2 connected to antenna 2 is adjusted to W2 so that the coverage range S2 + S1 > L of antenna 2, where L = V * T1 and V is the running speed of the tag. Thus, the movement range of the tag during the write code time T1 is within the radiation ranges of antenna 1 and antenna 2.

[0025] 2. Initialization stage The reader is initialized according to the parameters in the preparation stage, waits for the trigger signal of the sensor, and then sends an instruction to communicate with the tag to be read and written through antenna 1 and antenna 2.

[0026] 3. Communication establishment When the tag to be detected enters the range of sensor 1, sensor 1 sends a trigger message to the reader. The reader discovers the communication request message through antenna 1 and establishes a stable one-to-one communication with the current tag. When the reader obtains the EPC or TID, etc. of the current tag, it enters the dynamic adjustment stage.

[0027] Place sensor 1 at the starting point of the trigger point within the coverage range of the incoming antenna 1 of the tag. Sensor 1 is connected to the reader. When sensor 1 is triggered, the reader sends an RFID communication command to the tag through antenna 1. When the tag responds correctly, the communication link between the reader and the tag is established. Generally, the communication establishment time is about 1 ms. At this time, the tag usually moves a very small distance and is still within the coverage range of antenna 1. After the communication link between the reader and the tag is established, the communication continues with the tag according to the communication protocol.

[0028] 4. Coding Execution and Dynamic Adjustment Phase Since the reader has established communication with the current tag, before the end of this communication (inventory access), other RFID tags, and even tags within the antenna radiation range, will not communicate with the reader.

[0029] After the communication connection is established, the reader performs a coding operation on the current tag through antenna 1. After time T1, it reaches the boundary point of the radiation range of the current antenna and enters the dynamic adjustment phase.

[0030] The purpose of dynamic adjustment is to adjust the physical communication range between the reader device and the tag so that the current tag is within the communication radio frequency radiation range of the reader throughout the communication range. In this embodiment, the method of dynamic adjustment is to dynamically adjust the radio frequency port connected to the antenna with a larger radiation range: that is, when the reader obtains the EPC or TID of the current tag, etc., the antenna of the reader is adjusted from antenna 1 to antenna 2.

[0031] This kind of dynamic control can write the control logic into the reader internally for the reader to control itself, or it can be set and configured through an external system such as a computer or an industrial control computer to adjust. This kind of dynamic control can be achieved by adjusting the internal device parameters of the reader, or by installing devices such as radio frequency switches outside the reader.

[0032] In the case where the reader is equipped with multiple radio frequency ports, switch to the radio frequency port connected to the antenna with a larger radiation range according to the position of the tag to expand the coding range. Multiple antenna ports usually use a radio frequency switch to achieve port switching. The main control chip configures the radio frequency switch to achieve antenna port switching. This solution can also enable the radio frequency port connected to the antenna with a larger radiation range to emit signals by controlling the on / off of PIN diodes, that is, at this time, multiple antenna ports have radio frequency signal outputs. But it is not limited to the methods exemplified.

[0033] Specifically: Place sensor 2 at the trigger point within the coverage range of the incoming antenna 2 of the tag. Sensor 2 is connected to the reader. When sensor 2 is triggered, the reader internally sends a radio frequency signal, switches to antenna 2, and at the same time sets the transmission power of port 2 to W2.

[0034] After adjusting the transmission power or RF port, continue to perform the label coding operation. The reader continues to send communication instructions through antenna 2 to communicate with the label until the entire writing operation is completed.

[0035] 5. End of the inventory cycle After completing the label coding, restore the initial settings. The reader switches the RF signal back to port 1 and sets the power to W1, preparing for the next label coding.

[0036] In this embodiment, the reader is connected to two antennas, namely antenna 1 and antenna 2. The transmission power of antenna 1 is set to W1, and the transmission power of antenna 2 is set to W2. Sensors 1 and 2 are respectively set at the trigger points where the label enters the coverage ranges of antenna 1 and antenna 2.

[0037] When the label enters the coverage range of antenna 1, sensor 1 is triggered, and the reader establishes a communication link with the label through antenna 1. After the communication link is established, the reader performs a coding operation on the current label through antenna 1. After time T1, it reaches the boundary point of the radiation range of the current antenna and enters the dynamic adjustment stage. The RF signal is switched to antenna 2, and the transmission power is adjusted to W2 to expand the coding range. After completing the coding operation, the reader switches the RF signal back to antenna 1 and restores the transmission power to W1, preparing for the next label coding operation. In this embodiment, by dynamically switching the RF port, it can be ensured that the label is always within the effective communication range of the reader during the entire coding process, thus avoiding coding failure caused by the label exceeding the range and significantly improving the coding efficiency.

[0038] Embodiment 2 In this embodiment, the structure and working principle of a system for dynamically adjusting the coding range of ultra-high frequency RFID tags are basically the same. The difference is that in the coding execution and dynamic adjustment stage, after the communication connection is established, it immediately enters the dynamic adjustment stage. Although this scheme wastes a part of the radiation range of antenna 1, the switching condition is simple and stable, which is convenient for dynamic adjustment.

[0039] Embodiment 3 In this embodiment, the structures and working principles of a system for dynamically adjusting the coding range of ultra-high frequency RFID tags are basically the same. The differences are as follows: when switching to the RF port connected to the antenna with a large radiation range, the channel selection method is that the reader is only connected to one antenna, and the coding range is adjusted by dynamically adjusting the transmission power. When the tag enters the antenna coverage range, the reader triggers a signal through the sensor to establish a communication link with the tag. After the communication link is established, the reader dynamically adjusts the transmission power according to the position and movement speed of the tag to ensure that the tag is always within the radiation range of the antenna during the entire coding process. After the coding operation is completed, the reader restores the initial transmission power and prepares for the coding operation of the next tag.

[0040] For the adjustment of the transmission power, through the main control chip, the registers of the corresponding chips are configured to increase the transmission power of the RF port. The adjustment method can be to adjust the transmission power of the transceiver chip, adjust the gain of the power amplifier chip, adjust the attenuation value of the digital control attenuator, etc., but is not limited to the exemplified methods. Moreover, it can also work simultaneously in the manner of two channels and two antennas in Embodiment 1.

[0041] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as a limitation of the present invention itself. Various changes in form and detail may be made without departing from the spirit and scope of the present invention defined by the appended claims.

Claims

1. A method for dynamically adjusting the coding range of ultra-high frequency RFID tags, characterized in that, It includes the following steps: The communication link between the reader and the tag enters the dynamic adjustment stage according to a preset policy. After the dynamic adjustment stage is completed, the code writing operation of the tag is executed; The preset policy is as follows: after a stable one-to-one communication connection is established between the reader and the tag; or after the communication connection is established and the code writing operation is executed, when the current tag moves to the boundary point of the radiation range of the current antenna; In the dynamic adjustment stage, the adjustment scheme is: dynamically adjust the transmission power of the reader or switch the RF port connected to the antenna with a large radiation range.

2. The method for dynamically adjusting the coding range of a UHF RFID tag according to claim 1, characterized in that The method for judging that the tag moves to the boundary point of the radiation range of the current antenna is: after the current tag moves to the reading and writing range of the reader for time T1, it reaches the boundary point of the radiation range of the current antenna; where the time T1 = S1 / V, S1 is the effective reading and writing range length of the current antenna, and V is the running speed of the tag.

3. A method for dynamically adjusting the coding range of an ultra-high frequency RFID tag according to claim 1, characterized in that The method for dynamically adjusting the transmission power of the reader is: configure the registers of the corresponding chip through the main control chip to increase the transmission power of the RF port. The adjusted parameters include adjusting the transmission power of the transceiver chip, adjusting the gain of the power amplifier chip, adjusting the attenuation value of the digital control attenuator, etc.

4. A method for dynamically adjusting the coding range of a UHF RFID tag according to claim 1, characterized in that, The method for switching the RF port connected to the antenna with a large radiation range is: when the reader is equipped with multiple RF ports, switch to the RF port connected to the antenna with a large radiation range according to the position of the tag to expand the code writing range; multiple antenna ports usually use an RF switch to achieve port switching, and the main control chip configures the RF switch to achieve antenna port switching.

5. A method for dynamically adjusting the coding range of a UHF RFID tag according to claim 3, characterized in that, When switching to the RF port connected to the antenna with a large radiation range, the channel selection methods are: (1) switching between two channels and two antennas; (2) switching between multiple channels and multiple antennas; (3) not switching the antenna and adjusting the transmission power of the antenna; (4) multiple channels and multiple antennas, enabling multiple antennas to work simultaneously.

6. The method for dynamically adjusting the coding range of an ultra-high frequency RFID tag according to claim 1, characterized in that, In the dynamic adjustment stage, dynamic control adopts any one of the following methods: (1) write the control logic into the reader internally, and the reader controls itself; (2) control through an external system, such as a computer or an industrial control computer.

7. A system for dynamically adjusting the coding range of an ultra-high frequency RFID tag according to any one of claims 1 to 6, characterized in that It includes a reader, an antenna connected to the reader, and a sensor. The antenna is used to communicate with the RFID tag, and the sensor is used to detect the position of the tag and send a trigger signal to the reader.

8. A system for dynamically adjusting the coding range of ultra-high frequency RFID tags according to claim 7, characterized in that, There are 2 antennas, namely antenna 1 for establishing a one-to-one communication connection with the RFID tag and antenna 2 for executing the code writing operation of the tag. The radiation range of antenna 2 is larger than that of antenna 1.

9. The system for dynamically adjusting the coding range of an ultra-high frequency RFID tag according to claim 8, characterized in that, The position of antenna 1 is set to ensure that when the tag is in a certain position, the reader can only read this tag.

10. A system for dynamically adjusting the coding range of an ultra-high frequency RFID tag according to claim 7, characterized in that, The sensor is a physical sensor, or a trigger signal given by other devices, or a communication instruction given by the host.

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