A method for detecting multiple packet loss based on built-in vector label

Abstract

A multi-group missing tag detection method based on built-in vector, all known tags in the system are divided into G groups, let the gth group contain N g tags, N g ≤z, 1≤g≤G, wherein the number of missing tags is m g , each tag has a unique 96-bit tag ID and a group ID, the method comprises: the reader assigns a unique 96-bit tag sequence to each tag in the group; the reader writes a built-in vector composed of the group ID and the tag sequence into the corresponding tag memory, then the reader broadcasts the group ID of each tag in turn as an inquiry request; when the tag receives the inquiry request containing its group ID, it sends the tag sequence in the memory to the reader in the next tag time slot, then the reader performs an or operation on all tag responses received in a tag time slot to generate a new composite vector, and then judges whether a missing tag event has occurred according to the actual value in the composite vector.

Description

Technical Field

[0001] This invention relates to the fields of radio frequency identification and Internet of Things (IoT) technology, and specifically to a multi-group lost tag detection method based on built-in vectors. Background Technology

[0002] With more and more terminal devices connecting to the network, the Internet of Things (IoT) technology has developed rapidly. Radio Frequency Identification (RFID), as one of the key technologies of IoT, has achieved tremendous success in the past decade. A typical RFID system usually consists of a back-end server, one or more readers, and a large number of tags. The back-end server provides powerful computing and storage capabilities, and each reader is equipped with one or more antennas to collect tag responses within its communication range. Tags can be divided into active tags, semi-active tags, and passive tags according to their communication modes. Active tags are powered by internal power supplies and have long communication distances, but are larger in size; semi-active tags only enter the working state when activated; and passive tags do not have internal power supplies and rely on the radio frequency signals emitted by the reader for power. The back-end server stores the ID information of all known tags for real-time tag monitoring and provides real-time instructions to the readers to manage the tags in the system. In large-scale, multi-group RFID systems, such as those in large warehouses, all goods are tagged with RFID tags. Human error, such as theft or employee negligence, can lead to the loss of goods and significant economic losses. Rapid detection of lost tags can quickly identify lost goods and prevent such losses. In large-scale RFID systems, tags can be divided into multiple groups based on the attributes and characteristics of the goods, with each group having the same group ID. The most direct method for detecting lost tags is to collect the IDs of all tags in the system and compare them with the IDs stored on the server. If the ID is not found on the server, the tag can be considered lost. This method has the advantage of high accuracy, but its disadvantages are also significant. Because this method requires frequent ID transmission between the reader and the tag, it consumes a lot of time, resulting in extremely low detection efficiency and posing significant security risks. Summary of the Invention

[0003] In view of the technical defects and drawbacks existing in the prior art, embodiments of the present invention provide a multi-group lost label detection method based on built-in vectors to overcome or at least partially solve the above problems. The specific solution is as follows:

[0004] To achieve rapid detection of lost tags in a large-scale, multi-group RFID system, this invention proposes a multi-group lost tag detection method based on built-in vectors. In the proposed method, the large-scale, multi-group RFID system includes a backend server with powerful computing and storage capabilities. Its database records the IDs of all known tags, and its computing power provides real-time instructions to the reader for managing and synchronizing tags within the system. All known tags in the system are divided into G groups, each containing N tags. g There are (1≤g≤G) labels, of which m labels are missing. g Each tag has a unique z-bit ID and a group ID, which are used to verify the tag's identity.

[0005] The C1G2 standard, developed by the EPCglobal organization, specifies the communication guidelines between readers and tags. A tag contains four different memory banks, called MemBanks, used to store different information. MemBank-0, MemBank-1, and MemBank-2 are used to store passwords, Electronic Product Codes (EPCs), and TIDs, respectively. MemBank-3 is readable and writable and can be customized by the user. Furthermore, the Select command specified in the C1G2 protocol selects the corresponding tag by comparing the information in the tag's MemBanks, prompting a response. This method includes:

[0006] Step 1: The reader assigns a unique z-bit tag sequence to the tags in each group;

[0007] Step 2: The reader writes the built-in vector consisting of the group ID and the tag sequence into the memory of the corresponding tag. Then, the reader broadcasts the group ID of each tag in turn as a query request.

[0008] Step 3: When a tag receives an inquiry request containing its group ID, it sends the tag sequence in memory to the reader in the next tag time slot. Then, the reader performs an OR operation on all tag responses received in a tag time slot to generate a new composite vector. Then, it determines whether a tag loss event has occurred based on the actual value in the composite vector.

[0009] Furthermore, step 1 also includes: the reader sorts the tags in ascending order based on their tag IDs, and when the number of tags in a group is greater than z, it divides them into... Create subgroups, such that the number of labels in each subgroup is less than or equal to z, and set a subgroup index for each subgroup.

[0010] Furthermore, in step 2, the reader writes the built-in vector consisting of group ID, subgroup index and tag sequence into the memory of the corresponding tag, and then the reader broadcasts the group ID and subgroup index of each tag in turn as a query request.

[0011] Furthermore, in step 3, after a tag receives an inquiry request containing its group ID and subgroup index, it sends the tag sequence in memory to the reader in the next tag time slot.

[0012] Furthermore, the reader divides all groups with more than z tags into multiple subgroups, and then broadcasts the group ID of the tag and the corresponding subgroup index in sequence. After each broadcast, a tag time slot is opened, and the tags belonging to the broadcast group ID and subgroup send the z-bit tag sequence to the reader in the next tag time slot.

[0013] Furthermore, in step 3, if the value of a certain bit in the composite vector is "0", it is determined that a tag loss event has occurred in that group of tags.

[0014] Further, in step 1, assigning a unique z-bit label sequence to the labels in each subgroup includes:

[0015] The reader sorts the tags in a group in ascending order by tag ID. The first tag's tag sequence is set to "1" and the remaining bits are set to "0". Then the second tag's tag sequence is set to "1" and the remaining bits are set to "0", and so on. The j-th tag's tag sequence is set to "1" and the remaining bits are set to "0".

[0016] The present invention has the following beneficial effects:

[0017] (1) The present invention can realize the detection of lost tags in a large-scale multi-group RFID system with high precision and efficiency, quickly and accurately detect lost tags in each group of tags, and the reliability of the detection can reach 100%.

[0018] (2) The present invention provides each tag with a built-in vector with unique characteristics, so that each tag is unique, thereby avoiding information conflicts caused by tag responses.

[0019] (3) The present invention makes full use of tag time slots, and contains z tag responses in each time slot, which not only improves the communication efficiency between the reader and the tag, but also avoids useless empty time slots, greatly improving the detection efficiency. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the multi-group lost label detection method based on built-in vectors provided in an embodiment of the present invention.

[0021] Figure 2 This is a structural diagram of a multi-group RFID system provided in an embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram illustrating the process of the multi-group lost label detection method based on built-in vectors in an embodiment of the present invention.

[0023] Figure 4 This diagram illustrates the comparison of the execution time of the multi-group lost label detection method based on built-in vectors in this embodiment of the invention and existing methods as the total number of system labels changes when α = 0.9.

[0024] Figure 5 This diagram illustrates the comparison of the execution time of the multi-group lost label detection method based on built-in vectors in this embodiment of the invention and existing methods as the total number of labels in the system changes when α = 0.99.

[0025] Figure 6 This diagram illustrates the comparison of the execution time of the multi-group lost label detection method based on built-in vectors in this embodiment of the invention and existing methods as the detection reliability of each group changes when M=1.

[0026] Figure 7 This diagram illustrates the comparison of the execution time of the multi-group lost label detection method based on built-in vectors in this embodiment of the invention and existing methods as the detection reliability of each group changes when M=5.

[0027] Figure 8 This diagram illustrates the comparison of the execution time of the multi-group lost label detection method based on built-in vectors in this embodiment of the invention and existing methods as the number of lost labels in each group changes when α = 0.9.

[0028] Figure 9 This diagram illustrates the comparison of the execution time of the multi-group lost label detection method based on built-in vectors in this embodiment of the invention and existing methods as the number of lost labels in each group changes when α = 0.99.

[0029] Figure 10 This diagram illustrates the comparison of the actual detection reliability of the multi-group lost tag detection method based on built-in vectors in this embodiment of the invention and existing methods as the number of tags in each group changes when α = 0.9.

[0030] Figure 11 This diagram illustrates the comparison of the actual detection reliability of the multi-group lost tag detection method based on built-in vectors in this embodiment of the invention and existing methods as the number of tags in each group changes when α = 0.99.

[0031] Figure 12 This diagram illustrates the comparison of the detection reliability of each group in the multi-group lost label detection method based on built-in vectors in this embodiment of the invention and existing methods when M=1.

[0032] Figure 13 This diagram illustrates the comparison of the detection reliability of each group in the multi-group lost label detection method based on built-in vectors in this embodiment of the invention and existing methods when M=5. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] See Figure 2 A large-scale multi-group RFID system includes a back-end server, a reader, and n known tags divided into G groups, where the i-th tag group contains g tags. i 1 label, containing m i One tag is a lost tag, 1≤i≤G, and the remaining tags are present tags. Each tag in the system has a unique z-bit ID. In this embodiment, z is 96, meaning each tag has a unique 96-bit ID. This ID can accurately identify the identity, attributes, and other information of each tag. The reader communicates with tags within its communication range via radio frequency signals emitted by its antenna. All tag IDs are stored in the backend server, and the reader can obtain the tag ID information at any time for real-time tag monitoring. To improve the communication efficiency between the reader and the tags and reduce information conflicts, the communication between the reader and the tags is based on the frame slot Aloha protocol.

[0035] like Figure 1 As shown, the multi-group lost tag detection method based on built-in vectors detects lost tags in the aforementioned multi-group RFID system, and includes the following steps:

[0036] Step 1: The reader assigns a unique 96-bit tag sequence to the tags in each group;

[0037] Step 2: The reader writes the built-in vector consisting of the group ID and the tag sequence into the memory of the corresponding tag. Then, the reader broadcasts the group ID of each tag in turn as a query request.

[0038] Step 3: When a tag receives an inquiry request containing its group ID, it sends the tag sequence in memory to the reader in the next tag time slot. Then, the reader performs an OR operation on all tag responses received in a tag time slot to generate a new composite vector. Then, it determines whether a tag loss event has occurred based on the actual value in the composite vector.

[0039] In the above embodiments, since one tag slot can be used to transmit 96 bits of information, we set the length of the tag sequence to 96 bits so that the sequence can be transmitted in one tag slot.

[0040] In one specific embodiment, step 1 includes: For any group of tags g (1≤g≤G), the IDs of all tags in the group are stored in the backend server. The reader first constructs a unique built-in vector for each tag based on the number of tags in the RFID system. Each tag's built-in vector consists of three parts: a group ID, a subgroup index, and a 96-bit tag sequence. The group ID is user-defined, while the length of the subgroup index is determined by the number of tags in the group. When the number of tags in a group is greater than 96, the tags in that group are divided into... There are 96 subgroups. All tags in the group have the same group ID. The subgroup index of the first subgroup of 96 tags is "0...00", the subgroup index of the second subgroup of 96 tags is "0...01", and so on.

[0041] In the first subgroup, the first tag's tag sequence has a "1" as its first bit and the rest "0", resulting in the tag sequence "10…00". The second tag's tag sequence has a "1" as its second bit and the rest "0", resulting in "01…00". The l-th tag's tag sequence has a "1" as its l-th bit and the rest "0", while the 96th tag's tag sequence is "00…01". The correct tag sequences for the second subgroup are constructed in the same way.

[0042] In one specific embodiment, in step 2, after all the tag sequences of the group of tags have been constructed, the reader writes the built-in vector composed of the group ID, subgroup index and tag sequence into the tag's memory through a write operation. This built-in vector represents the uniqueness of the tag.

[0043] After the reader writes the built-in vectors of all tags into the tag's memory, it queries the tags by broadcasting the tag's group ID and subgroup index. When a tag receives its group and subgroup index, it sends its 96-bit tag sequence from memory to the reader in the following tag slot. After receiving responses from all tags in a tag slot, the reader performs an OR operation on these responses to generate a new 96-bit composite vector. If any bit in the composite vector is "0", it indicates that a lost tag exists in that group. At this point, the reader immediately terminates the detection for that group and begins the detection of lost tags for the next group by broadcasting the group ID and subgroup index of the next group.

[0044] The above process is repeated until all labels in all groups have been detected.

[0045] To further illustrate the advantages of the above-described method of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0046] See Figure 3 Assuming a group of 480 tags in an RFID system is divided into 5 groups, each with z tags. Since all tags belong to the same group, their group IDs are identical, "1101". There are 5 subgroups, and the subgroup index length is 3. The indices of each subgroup are "000", "001", "010", "011", and "100". For a z-bit tag sequence, the first tag in each subgroup has a "1" in its first bit and "0" in the other bits; the second tag in each subgroup has a "1" in its second bit and "0" in the other bits, and so on, until the z-th tag in each subgroup has a "1" in its z-bit bit and "0" in the other bits. After all the built-in vectors are written to the tag memory, the reader sequentially broadcasts the group ID and subgroup index of each tag. When a tag receives its group ID and subgroup index, it sends its z-bit tag sequence to the reader. The reader then performs an OR operation on the tag responses in a tag slot to generate a new composite vector. If any bit in the composite vector is "0", then there are lost tags in that group.

[0047] When the required reliability of the multi-group RFID system is α = 0.9 and α = 0.99 respectively, the multi-group lost tag detection method based on built-in vectors described in this invention (hereinafter referred to as the AEMD method) is used in conjunction with the existing GAB-detect method and SMTD+CC method for lost tag detection. See [link to relevant documentation]. Figure 4 and Figure 5 It can be observed that as the number of tags in the system increases, the time cost of the three methods also increases, but the time efficiency of the AEMD method described in this invention is much higher than that of the other two methods.

[0048] When the thresholds for lost tags in each group of a multi-group RFID system are M=1 and M=5, the AEMD method described in this invention, along with the existing GAB-detect method and SMTD+CC method, are used for lost tag detection. (See [link to relevant documentation]). Figure 6 and Figure 7 It can be observed that as the number of tags in the system increases, the time cost of the three methods also increases, and the higher the required reliability, the more significant the increase in detection time. However, the time efficiency of the AEMD method described in this invention is still higher than that of the other two methods.

[0049] When the required reliability of the multi-group RFID system is α = 0.9 and α = 0.99 respectively, the AEMD method described in this invention is used in conjunction with the existing GAB-detect method and SMTD+CC method for lost tag detection. See [link to relevant documentation]. Figure 8 and Figure 9 As the number of missing labels in each group increased, the detection time of the three methods did not change, while the AEMD method took less time than the other two methods.

[0050] When the required reliability for the multi-group RFID system is α = 0.9 and α = 0.99, respectively, and the threshold for lost tags per group is M = 1 and M = 5, respectively, the AEMD method described in this invention, along with the existing GAB-detect method and SMTD+CC method, are used for lost tag detection. (See [link to relevant documentation]). Figure 10 , 11 Methods 1, 2, and 3 can all meet the system's given reliability requirements. However, it's worth noting that the AEMD method achieves 100% detection reliability under all conditions, far exceeding the other two methods.

[0051] As can be seen from the above, the multi-group lost tag detection method based on built-in vectors provided by the present invention can efficiently detect lost tags in multi-group RFID systems, and the reliability can reach 100%.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for detecting multiple packet loss based on built-in vector, characterized in that, All known tags in the system are divided into G groups, let the first group be G1 g The group contains N g tags, N g ≤ preset value z, 1 ≤ g ≤ G， Wherein, the number of missing tags is m g Each tag has a unique z-bit tag ID, and a group ID for tag identity verification, the method comprising: Step 1, the reader assigns a unique z-bit tag sequence to each tag in a group; Step 2, the reader writes an internal vector composed of group ID and tag sequence into the corresponding tag memory, then the reader broadcasts the group ID of each tag in turn as an inquiry request; Step 3, when the tag receives the inquiry request containing its group ID, it sends the tag sequence in the memory to the reader in the next tag time slot, then the reader ors all the tag responses received in a tag time slot to generate a new composite vector, and then judges whether there is a missing tag event according to the actual value in the composite vector; In step 1, a unique z-bit tag sequence is assigned to each tag in a sub-group, including: The reader arranges the tags in a group in ascending order of the tag ID, sets the first bit of the tag sequence of the first tag as "1" and the remaining bits as "0", then sets the second bit of the tag sequence of the second tag as "1" and the remaining bits as "0", and so on, sets the j bit of the tag sequence of the first tag as "1" and the remaining bits as "0". j ​ In step 3, if the value of a certain bit in the composite vector is "0", it is determined that there is a missing tag event in the group.

2. The method of claim 1, wherein, Step 1 further comprises: the reader arranging the tag IDs of the tags in ascending order, and when the number of tags in a certain group is greater than z, dividing the group into subgroups, so that the number of tags in each subgroup is less than or equal to z, and setting a subgroup index for each subgroup.

3. The method of claim 2, wherein the method further comprises: In step 2, the reader writes an internal vector composed of group ID, sub-group index and tag sequence into the corresponding tag memory, then the reader broadcasts the group ID and sub-group index of each tag in turn as an inquiry request.

4. The method of claim 3, wherein the method further comprises: In step 3, when the tag receives the inquiry request containing its group ID and sub-group index, it sends the tag sequence in the memory to the reader in the next tag time slot.

5. The method of claim 2, wherein the method further comprises: After the reader divides the groups with more than z tags into multiple sub-groups, it broadcasts the group ID and the corresponding sub-group index of the tags in turn, and starts a tag time slot after each broadcast. The tags belonging to the broadcasted group ID and sub-group send a z-bit tag sequence to the reader in the next tag time slot.

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