RFID multi-tag identification method, reader and tags

Abstract

The invention provides an RFID multi-tag identification method, a reader and tags which are mainly applied to an RFID multi-tag identification system to solve the problem of tag collision. The RFID multi-tag identification method divides a process of identifying the reader and the tags and exchanging information into a plurality of periods which comprise the inquiring period for the reader to generate inquiring orders to search the tags and the two response periods for the tags to respond the inquiring orders of the reader. The two groups of tags can respectively respond the same order of the reader in different response periods. One inquiring order of the reader can obtain response of the two groups of tags, so that the inquiring times of the reader in a multi-tag identification process is greatly reduced, the communication traffic between the reader and the tags is reduced in a tag identification process, and the system energy consumption is reduced. The RFID multi-tag identification method is simple and direct, easy to carry out and stable in performance, belongs to a non-memory anti-collision method and is suitable for passive RFID multi-tag identification systems and various RFID multi-tag identification application occasions.

Description

technical field [0001] The invention relates to an RFID system, in particular to an RFID multi-label identification method, a reader and a label. Background technique [0002] Radio Frequency Identification (RFID) technology is an automatic identification technology with the characteristics of real-time, fast and accurate collection. The RFID system uses radio frequency signals to achieve non-contact information transmission through spatial coupling (alternating magnetic field or electromagnetic field), and achieves the purpose of identifying target objects through the transmitted information. The reader and the tag communicate through the wireless channel. When multiple tagged objects enter the recognition range of the reader, multiple tags communicate with the reader at the same time, and the signals interfere with each other, and a collision occurs, causing the tag Identification and data transfer failed. Therefore, it is necessary to establish an effective anti-collisi...

AI Technical Summary

Problems solved by technology

[0008] The ALOHA algorithm identifies tags in groups based on time slots. The complexity of the algorithm is low, but there are two main problems in this algorithm: First, because the slot numbers are randomly generated by tags, some tags may not be identified all the time. That is, the label starvation phenomenon; second, due to the limitation of the number of time slots, when the number of labels increases, the performance of the algorithm drops sharply

The Dynamic Frame Slot ALOHA Algorithm (DFSA) improves the performance of the algorithm by dynamically adjusting the size of the frame, but it needs to calculate and estimate the number of tags to be identified, and the algorithm is more complicated

[0009] Tree algorithms such as Query Tree Algorithm (QT), Binary Tree Algorithm (BT), and Binary Search Algorithm (BS) ensure the complete identification of tags, but also increase the identification delay of the algorithm

Both the ALOHA algorithm and the tree algorithm inevitably have empty time slots or empty searches, that is, there are situations where there are no tag responses in certain time slots or search states, so the performance and efficiency of the recognition algorithm are greatly affected

At the same time, the performance of the tree algorithm is also affected by the distribution of label numbers

At present, many improved algorithms, such as fallback algorithm, pruning algorithm, inverted search, valuation algorithm and many other methods, although to a certain extent reduce the situation of empty time slot or empty search, but at the same time increase the complexity of the algorithm itself , which also increases the difficulty of algorithm implementation

[0010] It can be seen that the above-mentioned existing RFID multi-tag identification method obviously still has inconvenience and defects in use, and needs to be further improved urgently.

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