An adaptive anti-collision RFID reading and writing system

Abstract

The present invention discloses an adaptive anti-collision RFID reading and writing system, comprising a reader and a tag end; the reader comprises a power calculation unit, which is used to obtain an estimated number of tags and a number of communication time slots based on tag signals received by the reader; the tag end comprises a time slot selection unit, which selects a dedicated number of time slots for communicating with the reader based on the number of communication time slots published by the reader; the dedicated number of time slots of the tag end is matched with the number of communication time slots of the reader, so that the reader recognizes the tag end and obtains tag end data; the reader calculates the number of tags within a working range and estimates the number of communication time slots within a communication cycle, thereby realizing quantitative management of channel resources; the tag end introduces a time slot selection unit based on the number of time slots published by the reader, and calculates and selects the dedicated number of time slots used for communicating with the reader through an adaptive strategy, thereby effectively preventing data collisions.

Description

Technical Field

[0001] The present invention relates to the technical field of radio frequency identification, and in particular to an adaptive anti-collision RFID reading and writing system. Background Art

[0002] In the field of radio frequency identification (RFID), readers and radio frequency tags (hereinafter referred to as "tags") are the two main components that realize radio frequency identification functions through wireless communication and are widely used in areas such as product anti-theft, logistics control, and data collection.

[0003] In real-world applications, more than one tag may be within the operating range of a given reader. If multiple tags are transmitting wireless signals to the reader at the same time, data collisions may occur within the wireless channel, leading to data corruption and difficulty for the reader. Several anti-collision algorithms have been proposed, such as ALOHA, slotted ALOHA, and dynamic slotted ALOHA. However, these algorithms lack flexibility and make it difficult to accurately quantify the number of tags.

[0004] The present invention provides an adaptive anti-collision RFID reading and writing system solution, which is mainly aimed at the near-field RFID radio frequency wireless communication system with a communication distance of centimeters. The distance between the tag and the reader is very close; the tag communicates with the reader using load modulation. Summary of the Invention

[0005] The purpose of the present invention is to provide an adaptive anti-collision RFID reading and writing system. The reader circuit is improved and designed, and a power calculation circuit is introduced. Within a communication cycle, the number of tags within the working range is roughly calculated. Based on this, the number of communication time slots is estimated. The system also has its own calibration process to achieve quantitative management of channel resources. According to the number of time slots released by the reader, the tag circuit is improved and designed, and a time slot selection unit is introduced. Through an adaptive strategy, the tag calculates and selects the number of dedicated time slots used for communication with the reader, effectively preventing data collisions.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] An adaptive anti-collision RFID reading and writing system includes a reader and a tag end;

[0008] The reader / writer includes a power calculation unit, which is used to obtain an estimated number of tags and a number of communication time slots based on tag signals received by the reader / writer;

[0009] The tag end includes a time slot selection unit, which selects a dedicated time slot number for communicating with the reader / writer according to the communication time slot number issued by the reader / writer;

[0010] The dedicated time slot number of the tag end is matched with the communication time slot number of the reader / writer, so that the reader / writer can identify the tag end and obtain the tag end data.

[0011] As a further solution of the present invention: the reader / writer includes a microprocessor, the microprocessor is electrically connected to a receiving unit, and the power calculation unit is electrically connected between the receiving unit and the microprocessor;

[0012] The receiving unit is used to receive the tag signal sent by the tag end.

[0013] As a further solution of the present invention: the reader / writer further includes a transmitting unit, and the transmitting unit is electrically connected to the microprocessor;

[0014] The transmitting unit is used to receive instruction information from the microprocessor and send the received instruction information to the corresponding tag end through the antenna.

[0015] As a further solution of the present invention: the reader / writer further includes a clock unit and a storage unit;

[0016] The hour hand unit is electrically connected to the microprocessor, and is used to provide clock timing information for the operation of the reader;

[0017] The storage unit is electrically connected to the microprocessor, and is used to provide storage space for the reader / writer.

[0018] As a further solution of the present invention: the reader / writer further includes a power supply unit, and the power supply unit is used to provide power for the operation of the reader / writer.

[0019] As a further solution of the present invention: the tag end includes a logic control unit, and the logic control unit is electrically connected to the time slot selection unit;

[0020] The logic control unit is used for tag-side data control and performs data processing on the dedicated time slot number of the time slot selection unit.

[0021] As a further solution of the present invention: the tag end further includes a storage unit, and the storage unit is electrically connected to the logic control unit and the time slot selection unit;

[0022] The storage unit is used to provide storage space for tag end operation, and also selects the number of time slots of the time slot selection unit and records the number of dedicated time slots.

[0023] As a further solution of the present invention: the tag end further includes a demodulation unit, and the demodulation unit is electrically connected to the logic control unit;

[0024] The demodulation unit demodulates the signal sent by the tag end reader to obtain demodulated data, and the demodulation unit sends the demodulated data to the logic control unit.

[0025] As a further solution of the present invention: the tag end further includes a modulation unit, and the modulation unit is electrically connected to the logic control unit;

[0026] The modulation unit modulates the data of the logic control unit and sends the modulated data through the antenna.

[0027] As a further solution of the present invention: the tag end further includes a rectifier unit, which is used to rectify and filter the reader-writer coupling signal and convert it into a power supply to support the operation of the tag end.

[0028] Beneficial effects of the present invention:

[0029] (1) The present invention improves the reader circuit design and introduces a power calculation circuit. During one communication cycle, the number of tags within the working range can be roughly calculated. Based on this, the number of communication time slots can be estimated. The invention also has a built-in calibration process to achieve quantitative management of channel resources.

[0030] (2) The tag of the present invention improves the design of the tag circuit according to the number of time slots released by the reader, introduces a time slot selection unit, and calculates and selects the number of dedicated time slots used for communication with the reader through an adaptive strategy, effectively preventing data collisions;

[0031] (3) The present invention designs a batch operation mechanism for the reader to operate on tags. For the tags found within the working range, the reader can uniformly perform operations such as authentication, reading, writing, sleep, and sleep cancellation. Similar operations are processed in batches, which is simpler and more convenient than operating them one by one. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be further described below with reference to the accompanying drawings.

[0033] Figure 1 It is a flowchart of the reader / writer of the present invention;

[0034] Figure 2 It is a flowchart of the label side program of the present invention;

[0035] Figure 3 1 is a schematic diagram of the process of generating the number of dedicated time slots according to the present invention;

[0036] Figure 4 It is a schematic flow chart of the working method of the present invention;

[0037] Figure 5 This is a schematic diagram of the connection between the reader and the tag of the present invention. DETAILED DESCRIPTION

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0039] Example 1

[0040] See also Figure 1 As shown, the present invention is an adaptive anti-collision RFID reading and writing system, including a microprocessor, a clock unit, a storage unit, a power calculation unit, a receiving unit, a transmitting unit, a power supply unit and an antenna;

[0041] Wherein, the clock unit, storage unit, transmitting unit and receiving unit are all connected to the microprocessor;

[0042] Further:

[0043] The clock unit is used to provide clock timing information for system operation;

[0044] The storage unit is used to provide storage space for system operation;

[0045] The voltage unit is used to provide power for system operation;

[0046] The microprocessor is used to calculate the signal data of the power calculation unit, perform data analysis on the signal data, and send the obtained instruction information to the transmitting unit;

[0047] The receiving unit receives the tag signal sent by the tag end through the antenna;

[0048] The transmitting unit is used to transmit the received instruction information to the corresponding tag through the antenna;

[0049] The power calculation unit is used to process the tag signal sent by the receiving unit;

[0050] Specifically, the reader receives the tag signal sent by the tag through the antenna, which is pre-processed by the receiving unit and sent to the power calculation unit. The power calculation unit processes the tag signal to obtain signal data. The signal data includes the power value P of the actual tag signal received. recv , and then process the power value P of the received single tag signal single and the margin, and obtain the estimated number of labels and time slots [P recv / P single ]+1 ([·] is the rounding symbol);

[0051] The microprocessor receives the signal data from the power calculation unit, combines it with the communication protocol process, issues relevant instructions and transmits them to the transmitting unit, which then transmits them to the corresponding tag through the antenna.

[0052] Example 2

[0053] An adaptive anti-collision RFID reading and writing system. For tag design, the dynamic time slot method in the existing technology mostly determines the selected communication time slot by generating random numbers. However, this method still cannot avoid the situation where different tags use the same time slot, and thus cannot avoid the possibility of data collision. Therefore, on this basis, the tag of the adaptive anti-collision RFID system designed by the present invention adds the concept of a time slot selection unit. The tag composition is as follows Figure 2 As shown;

[0054] The tag includes a time slot selection unit, a storage unit, a logic control unit, a modulation unit, a demodulation unit, a rectification unit and an antenna;

[0055] The time slot selection unit is connected to the storage unit and the logic control unit, and the logic control unit is connected to the storage unit, the modulation unit and the demodulation unit;

[0056] The storage unit is used to provide storage space for system operation, provide resources for the time slot selection unit and record the selection results;

[0057] The rectifier unit is used to rectify and filter the reader-writer coupling signal and convert it into power to support the operation of the tag;

[0058] The logic control unit is used for logic processing and data control;

[0059] The modulation unit is used to modulate the data of the logic control unit and send it through the antenna;

[0060] The demodulation unit is used to demodulate the signal received by the antenna and send it to the logic control unit;

[0061] Specifically, the tag receives the query command signal sent by the reader through the demodulation unit, the demodulation unit demodulates the query command signal to obtain demodulated data, the demodulation unit sends the demodulated data to the logic control unit, the logic control unit performs logic processing and data control on the received demodulated data to obtain modulated data, the logic control unit sends the modulated data to the modulation unit, and the modulation unit sends the received modulated data through the antenna;

[0062] The logic control unit selects the dedicated time slot number used for communication between the tag and the reader through the time slot selection unit during the demodulation data processing to prevent data collision.

[0063] In this embodiment, the improvement to the tag lies in the addition of an adaptive and precise time slot selection unit. The UID (globally unique identifier) in the storage unit is combined with an adaptive time slot selection algorithm to divide the UID into a byte array. The weights 1-n are assigned from low byte to high byte, where n is determined by the length of the UID. Each byte is multiplied by its corresponding weight, and the sum is finally added to obtain a random number seed and generate a random number. This completes the time slot selection and obtains the dedicated time slot number used when responding to the reader broadcast.

[0064] If the number of time slots planned for the reader is 8 and the UID of the tag that complies with the ISO14443 standard is 0x05 / 0x06 / 0x07 / 0x08, then its random number seed is 5*4+6*3+7*2+8*1=60, which is used to generate a random number between 0 and 7 as the dedicated time slot number of the tag. By introducing the above weight calculation, the uniqueness of the random number seed generated by the tag is guaranteed to prevent data collision. For example, if the dedicated time slot number is generated as time slot 2, the generation process of other dedicated time slots is omitted in the same way. Figure 3 shown.

[0065] In a specific embodiment:

[0066] Taking ISO14443 standard as an example, refer to Figure 4-Figure 5 The process of this embodiment is as follows:

[0067] S1: The reader issues the "Request All" and "Search Card" commands;

[0068] S2: If the reader detects that multiple tags return data (data collision), it will recv / P single ]+1 Initially obtain the number of tags and the number of allocated time slots, and publish them; (If there is only a single tag, the process is the same as that of the ordinary read-write system, which is omitted here);

[0069] S3: Each tag generates a unique random number seed based on its own UID, and combines it with the allocated time slot number to obtain its own dedicated communication time slot;

[0070] S4: The reader issues the "search card" command again to verify the number of allocated time slots;

[0071] S5: Each tag responds in its own dedicated communication time slot. If the reader finds that there is an empty time slot or a collision time slot, it adjusts the number of allocated time slots based on 1, and then "searches for cards" for verification until there are no empty time slots or collision time slots.

[0072] S6: If the reader performs similar operations on the tags within the working range, a batch operation is performed, and each tag responds separately in the dedicated communication time slot. If different operations are performed on different tags, they can be selected and processed one by one.

[0073] After the above communication is completed, the design process ends. If a new tag is added or the reading and writing system starts working again, the process will proceed from the beginning to the bottom.

[0074] In summary, the principle of this solution is that the interaction between the tag and the reader antenna is similar to transformer coupling. The coupling power between the coils is related to factors such as the operating frequency, the number of coil turns, and the distance between the coils. The operating frequency of the reader and tag is usually fixed; the number of coil turns is determined by the manufacturing process and often has some empirical value. The distance between the tag and the reader is very close, so the influence of coil distance and attenuation factors can be ignored. Based on the above information, the power value P of the reader receiving a single tag signal can be estimated. single According to the power value P of the signal received by the reader from a single tag and the signal received from the collision tag recv ,After considering appropriate margin, the number of tags within the read and write range and the number of communication time slots can be estimated.

[0075] The above is a detailed description of an embodiment of the present invention. However, the content described is only a preferred embodiment of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. An adaptive anti-collision RFID reading and writing system, characterized in that: Including reader and tag end; The reader / writer includes a power calculation unit, which is used to obtain an estimated number of tags and a number of communication time slots based on tag signals received by the reader / writer; The tag end includes a time slot selection unit, which selects a dedicated time slot number for communicating with the reader according to the communication time slot number published by the reader. Specifically, the UID (globally unique identifier) in the storage unit is combined with an adaptive time slot selection algorithm to divide the UID into a byte array form, and assign weights 1-n from low byte to high byte, where n is determined by the length of the UID. Each byte is multiplied by its corresponding weight, and finally the sum is added to obtain a random number seed and generate a random number, completing the time slot selection and obtaining the dedicated time slot number used when responding to the reader broadcast; Matching the dedicated time slot number of the tag end with the communication time slot number of the reader / writer, completing the reader / writer's identification of the tag end and obtaining the tag end data; The tag end includes a logic control unit, and the logic control unit is electrically connected to the time slot selection unit; The logic control unit is used for tag-side data control and performs data processing on the dedicated time slot number of the time slot selection unit.

2. The adaptive anti-collision RFID reading and writing system according to claim 1, characterized in that: The reader / writer includes a microprocessor, the microprocessor is electrically connected to a receiving unit, and the power calculation unit is electrically connected between the receiving unit and the microprocessor; The receiving unit is used to receive the tag signal sent by the tag end.

3. The adaptive anti-collision RFID reading and writing system according to claim 2, characterized in that: The reader / writer further comprises a transmitting unit, and the transmitting unit is electrically connected to the microprocessor; The transmitting unit is used to receive instruction information from the microprocessor and send the received instruction information to the corresponding tag end through the antenna.

4. The adaptive anti-collision RFID reading and writing system according to claim 3 is characterized in that: The reader / writer further includes a clock unit and a storage unit; The hour hand unit is electrically connected to the microprocessor, and is used to provide clock timing information for the operation of the reader; The storage unit is electrically connected to the microprocessor, and is used to provide storage space for the reader / writer.

5. The adaptive anti-collision RFID reading and writing system according to claim 4, characterized in that: The reader / writer further includes a power supply unit, which is used to provide power for the operation of the reader / writer.

6. The adaptive anti-collision RFID reading and writing system according to claim 1, characterized in that: The tag end further includes a storage unit, which is electrically connected to the logic control unit and the time slot selection unit; The storage unit is used to provide storage space for tag end operation, and also selects the number of time slots of the time slot selection unit and records the number of dedicated time slots.

7. The adaptive anti-collision RFID reading and writing system according to claim 6, characterized in that: The tag end further includes a demodulation unit, and the demodulation unit is electrically connected to the logic control unit; The demodulation unit demodulates the signal sent by the tag end reader to obtain demodulated data, and the demodulation unit sends the demodulated data to the logic control unit.

8. The adaptive anti-collision RFID reading and writing system according to claim 7, characterized in that: The tag end further includes a modulation unit, and the modulation unit is electrically connected to the logic control unit; The modulation unit modulates the data of the logic control unit and sends the modulated data through the antenna.

9. The adaptive anti-collision RFID reading and writing system according to claim 8, characterized in that: The tag end further includes a rectifier unit, which is used to rectify and filter the reader-writer coupling signal and convert it into power to support the operation of the tag end.

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