Rfid anti-collision fast identification system in laboratory dense electronic tag scene

Abstract

The application discloses a laboratory dense electronic tag scene RFID anti-collision fast identification system and relates to the technical field of RFID electronic tag identification.The system comprises a bottle position environment parameter acquisition module, a shielding matrix construction module, a hidden collision grouping module, a response suppression control module and a label bottle position matching module; the bottle position topography, the adjacent bottle position spacing and the read-write area boundary parameters in the reagent cabinet or the tray are acquired, twice pre-inquiries are carried out with different transmission powers, the RSSI, the phase drift and the liquid absorption attenuation difference of the labels under the same response time slot are obtained, the bottle position shielding matrix is constructed, the label response characteristic vector is generated, the hidden collision groups are divided, the step inquiry power and the reverse time slot sequence are generated, the near-end labels are delayed to respond, the weak response labels are preferentially returned, and finally the corresponding relationship between the label number and the bottle position number is output; and the application can improve the dense reagent bottle label identification accuracy and the inventory efficiency.

Description

Technical Field

[0001] This invention relates to the field of RFID electronic tag identification technology, specifically to an RFID anti-collision rapid identification system for dense electronic tag scenarios in laboratories. Background Technology

[0002] In laboratories, a large number of reagent bottles are usually stored in reagent cabinets, fume hood drawers, or mobile trays. To facilitate the entry and exit of hazardous chemicals, expiration date management, and sample traceability, RFID electronic tags are often affixed to the reagent bottles, and batch identification is performed using readers. Because laboratory reagent bottles are small in size and placed at high density, the distance between adjacent bottles is often only enough to accommodate the bottle itself. Multiple RFID tags that are spatially close to each other are likely to respond simultaneously within the same query cycle of the reader.

[0003] Existing RFID anti-collision methods mostly rely on dynamic frame time slots, binary tree queries, or power adjustment for tag inventory, typically assuming tags are in a relatively open reading environment with minimal obstruction. However, in laboratory settings with densely packed reagent bottles, the metal inner walls of reagent cabinets, tray edges, curved surfaces of bottles, and the liquid inside the bottles collectively cause RF signal reflection, absorption, and multipath interference. Especially when acid and alkali reagents, saline solutions, or high-dielectric liquids are placed together, the RSSI and phase changes of tags in different positions are unstable. Some distant or obstructed tags will exhibit weak responses, while tags closer to the antenna tend to repeatedly occupy response time slots.

[0004] During actual inventory checks, if multiple reagent bottles of the same size, with similar label positions but different liquid media, exist simultaneously in the same tray, the reader may receive mixed signals from multiple tags within the same response time slot. This type of collision cannot be effectively resolved simply by increasing the frame length, because nearby tags will continue to return preferentially. Even if a weakly responding tag is assigned a new time slot, it may still be missed due to liquid absorption or cabinet obstruction, resulting in a hidden collision. In this case, the system may misclassify a reagent bottle as not yet received, not returned, or in an abnormal location, thus affecting the verification of hazardous chemical inventory, issuance tracking, and the inventory check of expired reagents.

[0005] Therefore, in laboratory scenarios where labels are densely packed in reagent cabinets or trays, bottle positions are fixed, but radio frequency shielding is complex, how to quickly distinguish and prioritize hidden collision labels by combining bottle position topology, read / write area boundaries, liquid absorption attenuation, and label response characteristics has become a technical problem that needs to be solved. Summary of the Invention

[0006] The purpose of this invention is to provide an RFID anti-collision rapid identification system for dense electronic tag scenarios in laboratories, in order to address the shortcomings of the prior art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: an RFID anti-collision rapid identification system for dense electronic tag scenarios in laboratories, comprising:

[0008] The bottle position environmental parameter acquisition module acquires the bottle position topology, the distance between adjacent bottle positions, and the boundary parameters of the reading and writing area in the reagent cabinet or tray. It also controls the reader to perform two pre-interrogations at the first and second transmission powers respectively to obtain the RSSI, phase drift, and liquid absorption attenuation difference of the tag under the same response time slot.

[0009] The occlusion matrix construction module constructs a bottle position occlusion matrix based on the bottle position topology, read / write area boundary parameters, and liquid absorption attenuation difference, and maps the RSSI and phase drift to the bottle position occlusion matrix to generate a tag response feature vector.

[0010] The concealed collision grouping module divides RFID tags with the same response time slot and whose tag response feature vectors fall into the same occlusion matrix unit into concealed collision groups, and generates a stepped interrogation power and reverse time slot sequence based on the distance between adjacent bottle positions and the phase drift amount within the group.

[0011] The response suppression control module performs secondary interrogation on the concealed collision group according to the stepped interrogation power and reverse time slot sequence, causing the near-end tag to enter a delayed response state and the weak response tag to return first.

[0012] The label bottle position matching module matches the result of the second query with the label response feature vector and outputs the correspondence between the label number and the bottle position number.

[0013] Preferably, obtaining the liquid absorption attenuation difference includes:

[0014] Under the first and second transmit power, tag responses with the same phase drift direction within the same response time slot are selected as homogeneous responses; based on the spatial path distance from the candidate bottle position to the reader antenna, the RSSI difference of the homogeneous responses is normalized to obtain the normalized RSSI difference; the theoretical power difference between the first and second transmit power is used to perform residual calculation with the normalized RSSI difference, and the residual attenuation difference between different homogeneous responses within the same response time slot is used as the liquid absorption attenuation difference.

[0015] Preferably, determining the phase drift direction includes:

[0016] Based on the phase values ​​under the first and second transmission powers, the phase drift of the corresponding tag response is calculated; based on the reader's phase resolution, the phase drift is classified as positive drift, no drift, or negative drift; tag responses located in the same response time slot and with the same phase drift direction are identified as homogeneous responses.

[0017] Preferably, the construction of the bottle occlusion matrix includes:

[0018] The read / write direction from the near end to the far end is determined based on the boundary parameters of the read / write area. The projected distance of each bottle position along the read / write direction and the lateral projected distance perpendicular to the read / write direction are calculated. Two bottle positions located near the near end along the read / write direction and whose lateral projected distance difference is no greater than half the distance between adjacent bottle positions are established as a directed occlusion relationship. The liquid absorption attenuation difference corresponding to the same response time slot is written into the directed occlusion relationship to form a bottle position occlusion matrix.

[0019] Preferably, the determination of the attenuation occlusion value includes:

[0020] Based on the difference in projected distances between the two bottle positions along the read / write direction and the reference distance, the inter-bottle position occlusion distance factor is determined; the inter-bottle position occlusion distance factor is converted into a distance correction amount less than 1; the distance correction amount, the directional occlusion relationship, and the average liquid absorption attenuation amount in the same response time slot are multiplied together to obtain the attenuation occlusion value of the corresponding matrix element in the bottle position occlusion matrix.

[0021] Preferably, the generation of the label response feature vector includes:

[0022] The residual attenuation of the tag response is compared with the attenuation occlusion value in the bottle position occlusion matrix, and the matrix element with the smallest difference is selected as the occlusion matrix unit into which the tag response falls. The RSSI of the tag response is compensated according to the attenuation occlusion value of the occlusion matrix unit to obtain the occlusion compensation RSSI. The phase drift gradient is determined according to the direction of phase drift change in adjacent occlusion matrix units, and the response time slot, occlusion matrix unit, occlusion compensation RSSI and phase drift gradient are combined into the tag response feature vector.

[0023] Preferably, the division of the concealed collision group includes:

[0024] RFID tags with the same response time slot and falling into the same occlusion matrix unit are written into the same candidate collision queue; the RFID tags in the candidate collision queue are sorted from high to low according to the occlusion compensation RSSI; the phase drift gradient of adjacent RFID tags is read along the sorting result, and RFID tags with continuous and consistent phase drift gradients and no less than 2 are divided into the same covert collision group.

[0025] Preferably, the generation of the stepped interrogation power and reverse time slot sequence includes:

[0026] Based on the occlusion matrix unit into which the RFID tags fall within the concealed collision group, the minimum center distance between the candidate bottle position on the occluded side and its adjacent bottle positions is read, and a bottle position density sequence is generated according to the minimum center distance from smallest to largest. According to the minimum transmit power step allowed by the reader, an increasing step interrogation power is sequentially assigned to the bottle position density sequence, and the step interrogation power does not exceed the second transmit power. The original phase response order is formed according to the phase drift of the RFID tags within the group from largest to smallest, and this order is reversed to obtain a reverse time slot sequence.

[0027] Preferably, the near-end tag enters the delayed response state including:

[0028] Within the current re-interrogation slot of the reverse time slot sequence, RFID tags that have not yet completed confirmation, whose execution position is after the current priority interrogation target, and whose occlusion compensation RSSI is greater than that of the current priority interrogation target are identified as near-end delayed targets. The number of delay slots is determined based on the difference between the execution position of the near-end delayed target in the reverse time slot sequence and the position of the current re-interrogation slot. A selection inventory instruction is sent to the near-end delayed target through the tag number or temporary response handle, so that it is in a non-target state within the number of delay slots.

[0029] Preferably, the output of the correspondence between label numbers and bottle position numbers includes:

[0030] Based on the secondary interrogation RSSI, secondary interrogation phase value, and the occlusion compensation RSSI and pre-interrogation phase value in the corresponding tag response feature vector, calculate the RSSI matching deviation and phase matching deviation. When the RSSI matching deviation is no greater than twice the minimum resolution of the reader's RSSI and the phase matching deviation is no greater than twice the phase resolution of the reader, confirm that the secondary interrogation result matches the tag response feature vector. Determine the set of candidate bottle positions within the same occlusion zone based on the occlusion matrix unit into which the matched tag response falls. Arrange the confirmed tags in ascending order according to the re-interrogation slot number, and arrange the candidate bottle positions from far end to near end along the reading and writing direction. Establish a correspondence between the tag number and the bottle position number with the same sequence number.

[0031] The technical effects and advantages provided by the present invention in the above technical solution are as follows:

[0032] This invention does not simply address tag collisions by increasing frame length, random backoff, or uniformly adjusting transmission power. Instead, it first incorporates the topology of bottle positions in laboratory reagent cabinets or trays, the boundaries of read / write areas, the distance between adjacent bottle positions, and the difference in liquid absorption attenuation into the recognition process, constructing a bottle position occlusion matrix corresponding to the actual bottle position occlusion relationship. Through two pre-interrogations with different transmission powers, the RSSI, phase drift, and residual attenuation difference of the tag under the same response time slot are extracted and mapped to specific occlusion matrix units. This enables the system to distinguish between ordinary in-frame collisions and hidden collisions caused by dense placement of reagent bottles, liquid absorption, and near-far occlusion. This method directly solves the problem of existing technologies being unable to determine which bottle position occludes weak response tags and why they are repeatedly missed in complex scenarios such as metal reagent cabinets, densely packed vials, and liquid media. This improves the targeting of subsequent group interrogations and reduces invalid duplicate inventory counts.

[0033] Furthermore, this invention achieves hierarchical release and priority identification of dense tags through a combination of concealed collision groups, stepped interrogation power, reverse time slot sequences, and near-end delayed response. Specifically, tags with the same response time slot and falling into the same occlusion matrix unit are first grouped into concealed collision groups based on occlusion compensation RSSI and phase drift gradient. Then, stepped interrogation power is generated according to the distance between adjacent bottle positions within the group, and a re-interrogation time slot is generated in reverse according to the phase drift amount, allowing weak-response tags to get a return opportunity first. At the same time, near-end tags with high occlusion compensation RSSI and easy channel occupation are set to a delayed response state. This technique does not simply reduce power or randomly reread, but rather orderly separates near-end and far-end tags based on the density of bottle positions and occlusion propagation characteristics. This reduces the probability of strong near-end tags repeatedly occupying time slots, improves the first-time confirmation rate of far-end or liquid-occluded tags, and makes the correspondence between the final output tag number and bottle position number more stable and more suitable for hazardous chemical reagent inventory, return verification, and abnormal bottle position tracking. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0035] Figure 1 This is a flowchart of the bottle location environmental parameter acquisition and tag response acquisition process of the present invention;

[0036] Figure 2 This is a flowchart of the occlusion matrix construction and label feature generation process of the present invention;

[0037] Figure 3 This is a flowchart of the system modules of the present invention;

[0038] Figure 4 This is a flowchart of the label recognition and matching process of the present invention. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 some embodiments of the present invention, not all 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.

[0040] Example 1, please refer to Figure 1 and Figure 2 and Figure 3 and Figure 4 As shown in this embodiment, the RFID anti-collision rapid identification system for a laboratory with dense electronic tags includes:

[0041] The bottle position environmental parameter acquisition module acquires the bottle position topology, the distance between adjacent bottle positions, and the boundary parameters of the reading and writing area in the reagent cabinet or tray. It also controls the reader to perform two pre-interrogations at the first and second transmission powers respectively to obtain the RSSI, phase drift, and liquid absorption attenuation difference of the tag under the same response time slot.

[0042] In this embodiment, each bottle position in the reagent cabinet or tray is first numbered to obtain a set of bottle positions: ;in, Indicates the first One bottle position, This indicates the total number of bottle positions. Each bottle position... Corresponding to 1 row number and 1 column number The spacing between adjacent bottle positions includes the lateral spacing. and longitudinal spacing When reagent bottles are placed in a single row with equal spacing, take... .

[0043] The projection point of the reader antenna on the bottle position plane is used as the reference point. The vertical distance from the antenna to the plane of the bottle position is Bottle position The plane coordinates are determined by the following formula: , Bottle position Spatial path distance to reader antenna Determine using the following formula: Take the minimum value among all bottle location path distances as the reference distance. : Bottle position Distance normalization factor Determine using the following formula: ;in, This is a dimensionless value used to characterize the distance magnification relationship between the corresponding bottle position and the nearest bottle position. This distance normalization factor is derived from the bottle position topology, the distance between adjacent bottle positions, and the boundary parameters of the read / write area, and is used to reduce the impact of different distances from different bottle positions to the antenna on the comparison of RSSI differences.

[0044] Subsequently, the reader performs two pre-interrogations on the same reagent cabinet or tray. The first pre-interrogation uses the first transmission power. The second pre-interrogation used the second transmission power. And satisfy: During the two pre-interrogations, all stored parameters remained consistent except for the transmit power, including frame length, response slot numbering method, and operating frequency, to ensure the comparability of data collected under the same response slot. First transmit power. With the second transmission power power difference for: ; The values ​​of satisfy: ;in, This represents the minimum RSSI resolution of the reader / writer. This condition is determined based on the following: when the power difference is less than the RSSI resolution capability, the RSSI difference obtained from two pre-interrogations is easily overridden by reading fluctuations; therefore, a value not less than [a certain value] is used. This makes the RSSI difference distinguishable.

[0045] In this embodiment, the second transmission power Also satisfies: ;in, Indicating the second pre-interrogation RSSI of each response, This indicates that the reader / writer receives a saturation value. The RSSI is determined by reader calibration data, or by placing the RFID tag in the nearest bottle location and gradually increasing the transmission power until it no longer increases linearly with the transmission power. This condition is used to prevent nearby tags from responding too strongly and masking weakly responding tags.

[0046] In the first pre-query, record the first... Response time slot of each response RSSI value and phase value During the second pre-query, record the RSSI value in the same response time slot. and phase value . No. Phase shift of each response Determine using the following formula: ;in, Used to limit the phase difference Within the range, avoid phase crossing. This can lead to incorrect judgments.

[0047] Phase drift direction Determine using the following formula: ;in, This represents the reader's phase resolution, a value determined by the reader's phase sampling accuracy. (The two values ​​are located in the same response time slot.) And the phase drift direction The same response is selected as the same source response to exclude abnormal responses caused by reflections at the boundary of the read / write area or crosstalk from non-target bottle positions.

[0048] For any homogeneous response First, calculate the RSSI difference. : Then, based on the corresponding candidate bottle position of the response... Distance normalization factor Calculate the normalized RSSI difference : ;in, Indicates the first The candidate bottle number corresponding to each response in the bottle position topology. This represents the distance normalization factor for the candidate bottle location. This calculation reduces the impact of distance differences between different bottle locations on the comparison of RSSI increments.

[0049] Then, calculate the first... Residual decay of each homologous response : ;in, This represents the theoretical transmit power increment between two pre-interrogations. This represents the actual RSSI increment after distance normalization. The difference between the two values ​​characterizes the residual attenuation of the RFID signal caused by the liquid inside the bottle, the curved surface of the bottle, and bottle obstruction.

[0050] For the same response time slot Any two homologous responses and Liquid absorption attenuation difference Determine using the following formula: When the same response time slot Memory exists When there are multiple homologous responses, a set of liquid absorption attenuation differences is formed: ;

[0051] In this embodiment, the liquid absorption attenuation difference This value is used to characterize the degree of attenuation separation between different tag responses within the same response time slot due to differences in liquid absorption within the bottle. This value, along with the corresponding RSSI and phase shift, serves as the data basis for subsequently constructing the bottle occlusion matrix and generating tag response feature vectors.

[0052] The occlusion matrix construction module constructs a bottle position occlusion matrix based on the bottle position topology, read / write area boundary parameters, and liquid absorption attenuation difference, and maps the RSSI and phase drift to the bottle position occlusion matrix to generate a tag response feature vector.

[0053] After obtaining the bottle position topology, read / write region boundary parameters, and liquid absorption attenuation difference, the occlusion relationship between each bottle position within the reagent cabinet or tray is quantified. Let the set of bottle positions be... Each bottle position The coordinates on the bottle position plane are: The projection point of the reader antenna on the bottle positioning plane is... The unit direction vector from the near boundary to the far boundary of the read / write region is: ;and The perpendicular unit direction vector is: For any bottle position Calculate its projected distance along the read / write direction. Lateral projection distance in the vertical read / write direction : ; ;in, Used to indicate bottle position Relative to the position before and after the proximal boundary of the read / write region, Used to indicate bottle position Lateral offset position relative to the read / write direction. According to Arrange the bottles in ascending order to obtain the front-to-back obstruction order.

[0054] Let the distance between adjacent bottle positions be the horizontal distance. and longitudinal spacing Take the lateral distance for determination for: When reagent bottles are placed in a single row with equal spacing, take... The lateral judgment distance is determined by the actual spacing between the bottle positions and is not arbitrarily set. The boundary for determining the same blocking zone is that when the difference in lateral projection between two bottle positions is no greater than half the distance between adjacent bottle positions, the two have overlapping radio frequency propagation paths in the read / write direction; when it exceeds this range, the two are in different lateral channels and are not treated as a direct blocking relationship.

[0055] For any two different bottle positions and Establish directed occlusion relationship : ;in, Indicates bottle position Located in the bottle position The reading and writing direction is proximal, and both are within the same occlusion zone, bottle position Bottle position There is a directed occlusion relationship; This indicates that there is no occlusion relationship between the two in that direction. For the same bottle position, let: This setting is used to represent the unobstructed reference unit corresponding to the bottle position itself.

[0056] For the same response time slot Set of liquid absorption attenuation differences within: ;in, This indicates the number of homologous responses within the response time slot. When... Calculate the average liquid absorption attenuation in that response time slot. : ;when season: This value indicates that there is no comparable difference in liquid absorption within the response time slot, and no liquid absorption correction is applied to the inter-bottle obstruction value.

[0057] The minimum spatial path distance from all bottle positions to the reader antenna is: For bottle pairs with directed occlusion relationships Calculate the occlusion distance factor between bottle positions. : ;in, Indicates bottle position With bottle position The degree of spacing between the preceding and following parts in the reading and writing direction.

[0058] The bottle occlusion matrix is ​​denoted as: ; matrix elements Determine using the following formula: ;in, Indicates bottle position Bottle position The attenuation occlusion value. Using... The reason is that as the distance between the front and back increases, the occlusion effect increases; however, this ratio is always less than 1, which can prevent the distant bottle position from being given an infinitely large occlusion value due to the large distance.

[0059] Complete the bottle occlusion matrix Then, the RSSI and phase drift of the RFID tag in the same response time slot are mapped to this matrix. For the first... For each labeled response, the average RSSI obtained from two pre-queries is taken as the base RSSI: ;in, Indicates RSSI at the first transmit power. This indicates RSSI at the second transmit power.

[0060] Among them, the The residual decay of the tag response is .Will Compare the differences between the element and each element in the bottle occlusion matrix, and select the matrix element with the smallest difference as the occlusion matrix element corresponding to the label response: ;in, Indicates the first Each tag response falls into an occlusion matrix cell. If multiple matrix cells have the same difference, the cell with the same difference is selected first. The smallest matrix unit; if multiple results still exist, then select the smallest matrix unit. Smaller matrix units. This order is used to ensure the uniqueness of the mapping result.

[0061] Subsequently, occlusion compensation is performed on the basic RSSI based on the occlusion matrix unit into which the tag response falls, resulting in the occlusion-compensated RSSI: ;in, Indicates the first Occlusion compensation RSSI for each tag response, This represents the attenuation occlusion value of the corresponding occlusion matrix unit.

[0062] Next, calculate the phase drift gradient. Let the first... The phase shift of each tag response is For each occlusion matrix element If a tag response falls into this cell, the average phase drift of the tag responses falling into this cell is used as the phase value of that cell. : ;in, Indicates falling into the occlusion matrix element The set of tag responses, express The number of tag responses in the text.

[0063] For the The occlusion matrix unit corresponding to each tag response In the same line The preceding and following adjacent occlusion matrix elements are determined in ascending order. If the preceding adjacent occlusion matrix element does not have a valid phase value, its phase value is set to equal to... If the next adjacent occlusion matrix element does not have a valid phase value, its phase value is also set to equal to... Let the phase value of the previous adjacent occlusion matrix element be... The phase value of the next adjacent occlusion matrix unit is Then the phase drift gradient for: ;in, This represents the reader's phase resolution, which is determined by the reader's phase sampling accuracy and is not arbitrarily set by the user. This value is used to avoid misjudging the phase drift direction due to phase reading errors.

[0064] Finally, the occlusion matrix cell numbers, occlusion compensation RSSI, and phase drift gradients are combined in the order of bottle position numbers to generate the [number]. Each label response feature vector: ;in, Indicates the first The occlusion position, occlusion-corrected signal strength, and phase change direction of each RFID tag within the same response time slot are used to determine whether multiple RFID tags fall into the same occlusion matrix unit and to further divide them into concealed collision groups.

[0065] The concealed collision grouping module divides RFID tags with the same response time slot and whose tag response feature vectors fall into the same occlusion matrix unit into concealed collision groups, and generates a stepped interrogation power and reverse time slot sequence based on the distance between adjacent bottle positions and the phase drift amount within the group.

[0066] After obtaining the tag response feature vector, RFID tag responses falling into the same occlusion matrix unit within the same response time slot are divided. To ensure that the response time slot can be directly read subsequently, the tag response feature vector is represented as: ;in, Indicates the first The response time slot in which each RFID tag responds. This indicates that the RFID tag responded to the occlusion matrix cell it fell into. Indicates occlusion compensation RSSI, This represents the phase drift gradient. The phase drift of the RFID tag response is denoted as .

[0067] For any two RFID tag responses and If the following conditions are met simultaneously: ;as well as: The RFID tag will then respond. and RFID tag response Write them into the same candidate collision queue, denoted as: ;in, Indicates the response time slot is Occlusion matrix unit is The candidate collision queue is used. When the number of RFID tag responses in the candidate collision queue is less than 2, a covert collision group is not formed; when the number of RFID tag responses in the candidate collision queue is greater than or equal to 2, sorting and chaining continue.

[0068] For candidate collision queue The RFID tag responses are sorted from high to low according to the occlusion compensation RSSI, resulting in: ;in, This represents the number of RFID tag responses in the candidate collision queue, and satisfies: Subsequently, the phase drift gradients of adjacent RFID tag responses are read sequentially along the arranged sequence. For adjacent... and If the following conditions are met: Therefore, both belong to the same hidden collision chain.

[0069] If the following conditions are met: Then from A new covert collision chain is established. Each covert collision chain containing at least two RFID tag responses is divided into a covert collision group, denoted as: ;in, Indicates the first A concealed collision group This indicates the number of RFID tag responses within the group, and The classification result indicates that the RFID tags within the group have the same response time slot, the same occlusion matrix unit, and a continuous and consistent phase drift direction.

[0070] After obtaining the concealed collision group Then, the step query power required for the second query is generated. For the first query within the group... RFID tag response The occlusion matrix element it falls into is ,in The corresponding candidate bottle positions on the occluded side. Read the candidate bottle positions. The center distance between the RFID tag and its adjacent bottle positions is used, and the minimum center distance is taken as the spacing between adjacent bottle positions for the RFID tag response. ;

[0071] in, Indicates and Adjacent bottle positions, This represents the distance between the centers of two bottle positions. The minimum center-to-center distance is used because it corresponds to the direction where the bottle positions are most densely packed, and this direction is most likely to cause label responses to overlap.

[0072] according to Arrange the RFID tag responses within the group from smallest to largest to obtain the bottle position density sequence: And satisfy: Let the minimum allowable transmit power step of the reader be... This value is determined by the accuracy of the reader's transmission power adjustment. The [number]th [unit] in the bottle density sequence. The power increment step size corresponding to the response of each RFID tag is: The second question in the second inquiry The power of the first query is: ;when At that time, take: ;

[0073] in, The first transmission power, This is the second transmission power. This limitation ensures that the secondary interrogation power does not exceed the transmission power range verified during the pre-interrogation phase, preventing near-end RFID tags from masking weak-response tags again due to excessively strong responses.

[0074] Simultaneously, a reverse time slot sequence is generated based on the phase drift of the RFID tag responses within the group. First, according to... Arranged from largest to smallest, the original phase response order is obtained: ;in: Then, reverse the order to obtain the sequence of re-queries used in the second query: ;in: , Right now: ;in, This represents the sequence of RFID tag response objects sequentially assigned to each interrogation slot during the second interrogation. Indicates the first RFID tag responses are prioritized for processing within each query time slot. Because... Arranged in descending order of phase drift. After reversing, the RFID tags are arranged from smallest to largest phase drift. Therefore, within the same concealed collision group, the RFID tags with smaller phase drift are given priority and are given the first chance to return.

[0075] Finally, the power of the step query is bound sequentially to the sequence of re-queries to obtain the power-time slot combination: ;Will After substitution, the power-time slot combination can also be expressed as: ;in, Indicates the hidden collision group The execution order when performing a second query. Indicates the first The step-by-step query power used in the second and third queries. Indicates the first The RFID tag response corresponding to the second or third query should be prioritized.

[0076] During execution, the system first queries the RFID tag responses with smaller phase drift using a lower-order power, and then gradually increases the query power to process the responses of the remaining RFID tags. This reduces the probability of strong-response tags near the edge repeatedly occupying response time slots and increases the chance of weak-response tags being identified.

[0077] The response suppression control module performs secondary interrogation on the concealed collision group according to the stepped interrogation power and reverse time slot sequence, causing the near-end tag to enter a delayed response state and the weak response tag to return first.

[0078] In one implementation, the already divided concealed collision groups are interrogated a second time. Let the first... The concealed collision group is: ;in, ,and and All are concealed collision groups The RFID tag response within. The preceding steps have yielded the power-time slot combination corresponding to this concealed collision group: ; in the Individual inquiry time slot Inside, according to the combination item Adjust the reader's transmission power, and... The corresponding RFID tag response is prioritized for inquiry. Because The tags are arranged from smallest to largest phase drift. Therefore, tags with smaller phase drifts are prioritized for the second interrogation process. Combined with delayed response processing for near-end tags with higher occupancy compensation RSSI, the probability of near-end tags with strong responses repeatedly occupying the re-interrogation time slot can be reduced.

[0079] Establish the execution location for each RFID tag response in the reverse time slot sequence: ;in, Indicates RFID tag response The execution order in the second query.

[0080] In the In the second or third query, the current priority query target is Its occlusion compensation RSSI is The concealed collision group will include locations where confirmation and execution have not yet been completed. After that, and the occlusion compensation RSSI is greater than The RFID tag response was identified as a near-end object to be delayed: ;in, Indicates the first The set of near-end objects that need to be delayed in the second and third queries. Indicates RFID tag response Confirmation has not yet been completed. This determination does not set a separate threshold, but directly uses the magnitude relationship of the occlusion compensation RSSI; within the same occlusion matrix unit, the response with the higher occlusion compensation RSSI is more likely to occupy the channel first, and therefore it is regarded as the near-end object to be delayed.

[0081] for Any RFID tag response Calculate its delay time slot number: ;in, Indicates RFID tag response From the The number of re-interrogation slots that need to maintain a delayed response needs to be maintained starting from the second query. Because... ,therefore .

[0082] If the near-end pending delay object If the tag number or temporary response handle has already been obtained in the pre-interrogation or the previous valid response, the reader uses that tag number or temporary response handle as the selection field to send a selection inventory command, causing the RFID tag to be in... During a re-interrogation time slot, the RFID tag is in a non-target state; RFID tags in a non-target state do not return a response during the corresponding re-interrogation time slot. If a near-end object to be delayed has not yet obtained a tag number or temporary response handle, a selection inventory command is not sent to that object individually. Instead, the probability of repeated returns is reduced by using the current step interrogation power and the reverse time slot sequence to avoid addressing issues that could lead to implementation uncertainty.

[0083] After completing the processing of the near-end delayed object, the reader adjusts the transmit power to... and in the Individual inquiry time slot Perform a second query. If the reader receives returned data, and this returned data passes the CRC check or the checksum specified in the tag protocol, then record the tag number corresponding to the returned data and the second query RSSI. Second query phase value And query the slot number And record the confirmation status of the RFID tag response as: ;in, Indicates RFID tag response Confirmation has been completed. RFID tags that have been confirmed will remain in a non-target state during subsequent second interrogations within this covert collision group to prevent them from repeatedly occupying subsequent re-interrogation slots.

[0084] If the first If no valid response data is received in the individual query time slot, or if the response data fails verification, then keep... The confirmation status is: At this time, if Continue executing power-time slot combination The next item in the process; if the last item has been executed and no confirmation has been made, the RFID tag response is marked as a response pending review. Responses pending review are not included in the bottle location output of confirmed tags, but are only used for subsequent re-inventory.

[0085] After each re-query slot is completed, update the remaining delay slot count for near-end objects that are still in a non-target state: ;when When the RFID tag returns to its target state at its corresponding execution location; when At this time, the RFID tag remains in a non-target state. In this way, near-end tags with higher occlusion compensation RSSI will not return in the priority time slot of weak response tags, allowing tags with smaller phase drift and weaker response to complete identification first.

[0086] Finish After all the secondary queries, the results of the secondary queries for the hidden collision group are obtained: ;in, Used for subsequent matching with the label response feature vector; when When the RFID tag has obtained a valid tag number, it can proceed to the step of outputting the correspondence between the tag number and the bottle position number.

[0087] The label bottle position matching module matches the result of the second query with the label response feature vector and outputs the correspondence between the label number and the bottle position number.

[0088] To make the RSSI of the second interrogation comparable to the RSSI of the occlusion compensation phase, the RSSI of the second interrogation is calculated first: ;

[0089] in, This represents the attenuation occlusion value of the corresponding occlusion matrix element in the bottle position occlusion matrix.

[0090] The average transmit power during the pre-interrogation phase is: ;

[0091] The step query power used for the second query is Then the first The expected occlusion compensation RSSI for an RFID tag at this power is: ;

[0092] In the above calculations, both transmit power and RSSI are expressed in dBm or dB, therefore the power difference can be directly used for RSSI increment correction. The RSSI matching deviation is: ;

[0093] Then calculate the average phase value during the pre-interrogation phase: ;

[0094] in, This represents the phase value at the first transmit power. This represents the phase value at the second transmit power. The phase matching deviation is: ;

[0095] When both conditions are met: ;

[0096] as well as: ;

[0097] This confirms that the result of the second query matches the label response feature vector. Wherein, The minimum resolution of the RSSI for the reader / writer. The phase resolution of the reader is determined by the reader's sampling accuracy or calibration data.

[0098] use and The reason is that matching involves two sets of readings: a pre-interrogation and a second interrogation. The allowable deviation is the sum of the resolutions of the two samples, which can avoid false rejections due to single sampling errors.

[0099] After a successful match, candidate bottle positions are determined based on the occlusion matrix units. If: ;

[0100] The bottle position corresponding to this label is directly determined as follows: ;

[0101] like: ;

[0102] Then To read and write the proximal bottle position, with For candidate bottle positions on the shaded side, determine the set of candidate bottle positions within the same shading zone: ;

[0103] in, Indicates bottle position Projected distance along the read / write direction, Indicates bottle position Lateral projection distance in the vertical read / write direction.

[0104] For the same occlusion matrix unit The following sets are created based on the results of the second-order queries that have already been matched: ;

[0105] Will Re-query the slot number Arranged from smallest to largest, we get: ;

[0106] Set of candidate bottles according to Arranged from largest to smallest, we get: ;in, This ordering corresponds to the aforementioned reverse time-slot sequence: the reverse time-slot sequence causes weak response tags to return first, while within the same occlusion band, Larger bottle positions are located on the far end of the read / write process, and therefore are preferentially associated with earlier returned confirmed tags.

[0107] when At that time, establish a corresponding relationship according to the same sequence number: ;in, Indicates the first The label number in the result of a second query. Indicates bottle position Bottle position number.

[0108] when At that time, only for the former Establish bottle location correspondence for each confirmed label; the rest... Each label number is marked as pending review, and the bottle location number is not output to avoid multiple labels being assigned to the same bottle location.

[0109] The final output set is: ;in, This represents the set of correspondences between label numbers and bottle location numbers. Secondary query results that fail RSSI and phase matching, label numbers that fail protocol verification, and label numbers exceeding the number of candidate bottle locations are not included in the output set and are retained for subsequent re-inventory.

[0110] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. An RFID anti-collision rapid identification system for dense electronic tag scenarios in laboratories, characterized in that, include: The bottle position environmental parameter acquisition module acquires the bottle position topology, the distance between adjacent bottle positions, and the boundary parameters of the reading and writing area in the reagent cabinet or tray. It also controls the reader to perform two pre-interrogations at the first and second transmission powers respectively to obtain the RSSI, phase drift, and liquid absorption attenuation difference of the tag under the same response time slot. The occlusion matrix construction module constructs a bottle position occlusion matrix based on the bottle position topology, read / write area boundary parameters, and liquid absorption attenuation difference, and maps the RSSI and phase drift to the bottle position occlusion matrix to generate a tag response feature vector. The concealed collision grouping module divides RFID tags with the same response time slot and whose tag response feature vectors fall into the same occlusion matrix unit into concealed collision groups, and generates a stepped interrogation power and reverse time slot sequence based on the distance between adjacent bottle positions and the phase drift amount within the group. The response suppression control module performs secondary interrogation on the concealed collision group according to the stepped interrogation power and reverse time slot sequence, causing the near-end tag to enter a delayed response state and the weak response tag to return first. The label bottle position matching module matches the result of the second query with the label response feature vector and outputs the correspondence between the label number and the bottle position number.

2. The RFID anti-collision rapid identification system for dense electronic tag scenarios in laboratories according to claim 1, characterized in that, The acquisition of the liquid absorption attenuation difference includes: Under the first and second transmit power, tag responses with the same phase drift direction within the same response time slot are selected as homogeneous responses; based on the spatial path distance from the candidate bottle position to the reader antenna, the RSSI difference of the homogeneous responses is normalized to obtain the normalized RSSI difference; the theoretical power difference between the first and second transmit power is used to perform residual calculation with the normalized RSSI difference, and the residual attenuation difference between different homogeneous responses within the same response time slot is used as the liquid absorption attenuation difference.

3. The RFID anti-collision rapid identification system for dense electronic tag scenarios in laboratories according to claim 2, characterized in that, Determining the phase drift direction includes: Based on the phase values ​​under the first and second transmission powers, the phase drift of the corresponding tag response is calculated; based on the reader's phase resolution, the phase drift is classified as positive drift, no drift, or negative drift; tag responses located in the same response time slot and with the same phase drift direction are identified as homogeneous responses.

4. The RFID anti-collision rapid identification system for dense electronic tag scenarios in laboratories according to claim 2, characterized in that, The construction of the bottle occlusion matrix includes: The read / write direction from the near end to the far end is determined based on the boundary parameters of the read / write area. The projected distance of each bottle position along the read / write direction and the lateral projected distance perpendicular to the read / write direction are calculated. Two bottle positions located near the near end along the read / write direction and whose lateral projected distance difference is no greater than half the distance between adjacent bottle positions are established as a directed occlusion relationship. The liquid absorption attenuation difference corresponding to the same response time slot is written into the directed occlusion relationship to form a bottle position occlusion matrix.

5. The RFID anti-collision rapid identification system for dense electronic tag scenarios in laboratories according to claim 4, characterized in that, Determining the attenuation occlusion value includes: Based on the difference in projected distances between the two bottle positions along the read / write direction and the reference distance, the inter-bottle position occlusion distance factor is determined; the inter-bottle position occlusion distance factor is converted into a distance correction amount less than 1; the distance correction amount, the directional occlusion relationship, and the average liquid absorption attenuation amount in the same response time slot are multiplied together to obtain the attenuation occlusion value of the corresponding matrix element in the bottle position occlusion matrix.

6. The RFID anti-collision rapid identification system for dense electronic tag scenarios in laboratories according to claim 5, characterized in that, The generation of the label response feature vector includes: The residual attenuation of the tag response is compared with the attenuation occlusion value in the bottle position occlusion matrix, and the matrix element with the smallest difference is selected as the occlusion matrix unit into which the tag response falls. The RSSI of the tag response is compensated according to the attenuation occlusion value of the occlusion matrix unit to obtain the occlusion compensation RSSI. The phase drift gradient is determined according to the direction of phase drift change in adjacent occlusion matrix units, and the response time slot, occlusion matrix unit, occlusion compensation RSSI and phase drift gradient are combined into the tag response feature vector.

7. The RFID anti-collision rapid identification system for dense electronic tag scenarios in laboratories according to claim 6, characterized in that, The classification of the concealed collision group includes: RFID tags with the same response time slot and falling into the same occlusion matrix unit are written into the same candidate collision queue; the RFID tags in the candidate collision queue are sorted from high to low according to the occlusion compensation RSSI; the phase drift gradient of adjacent RFID tags is read along the sorting result, and RFID tags with continuous and consistent phase drift gradients and no less than 2 are divided into the same covert collision group.

8. The RFID anti-collision rapid identification system for dense electronic tag scenarios in laboratories according to claim 7, characterized in that, The generation of the stepped query power and reverse time slot sequence includes: Based on the occlusion matrix unit into which the RFID tags fall within the concealed collision group, the minimum center distance between the candidate bottle position on the occluded side and its adjacent bottle positions is read, and a bottle position density sequence is generated according to the minimum center distance from smallest to largest. According to the minimum transmit power step allowed by the reader, an increasing step interrogation power is sequentially assigned to the bottle position density sequence, and the step interrogation power does not exceed the second transmit power. The original phase response order is formed according to the phase drift of the RFID tags within the group from largest to smallest, and this order is reversed to obtain a reverse time slot sequence.

9. The RFID anti-collision rapid identification system for dense electronic tag scenarios in laboratories according to claim 8, characterized in that, Near-end tags entering a delayed response state include: Within the current re-interrogation slot of the reverse time slot sequence, RFID tags that have not yet completed confirmation, whose execution position is after the current priority interrogation target, and whose occlusion compensation RSSI is greater than that of the current priority interrogation target are identified as near-end delayed targets. The number of delay slots is determined based on the difference between the execution position of the near-end delayed target in the reverse time slot sequence and the position of the current re-interrogation slot. A selection inventory instruction is sent to the near-end delayed target through the tag number or temporary response handle, so that it is in a non-target state within the number of delay slots.

10. The RFID anti-collision rapid identification system for dense electronic tag scenarios in laboratories according to claim 9, characterized in that, The output of the correspondence between label numbers and bottle position numbers includes: Based on the secondary interrogation RSSI, secondary interrogation phase value, and the occlusion compensation RSSI and pre-interrogation phase value in the corresponding tag response feature vector, calculate the RSSI matching deviation and phase matching deviation. When the RSSI matching deviation is no greater than twice the minimum resolution of the reader's RSSI and the phase matching deviation is no greater than twice the phase resolution of the reader, confirm that the secondary interrogation result matches the tag response feature vector. Determine the set of candidate bottle positions within the same occlusion zone based on the occlusion matrix unit into which the matched tag response falls. Arrange the confirmed tags in ascending order according to the re-interrogation slot number, and arrange the candidate bottle positions from far end to near end along the reading and writing direction. Establish a correspondence between the tag number and the bottle position number with the same sequence number.

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