Passive network multi-user access method and related device

Abstract

The invention discloses a passive network multi-user access method and a related device, and the method comprises the steps: a reader-writer detects the label density in a network in real time, so as to judge the scene type; when the average access user number is smaller than the spreading code capacity, one-time high-power excitation access is adopted; and when the average number of access users is greater than the spreading code capacity, access is carried out by adopting a hierarchical excitation strategy, and the method and the related device can flexibly select an excitation mode according to the label density and optimize the system performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of passive network communications and relates to a passive network multi-user access method and related devices. Background Art

[0002] In large-scale passive tag networks, with the increasing number of tags and the increasing complexity of application scenarios, passive tag network access faces numerous challenges. Traditional multiple access methods such as TDMA (time division multiple access), FDMA (frequency division multiple access), and CDMA (code division multiple access) have significant drawbacks: TDMA has relatively low inventory efficiency, and its guard interval is affected by the sampling frequency offset (SFO) after clock calibration; FDMA is affected by large SFO of devices, resulting in a decrease in bit error rate, complex frequency resource management, and increased device power consumption; and CDMA, due to the limited capabilities of passive devices (such as large SFO / CFO) and cost factors, easily destroys code orthogonality, increases interference between devices, and reduces spectrum efficiency.

[0003] Existing technologies lack effective mechanisms for dynamically adjusting tag density when handling concurrent tag conflicts and signal interference. For example, conflict resolution efficiency is low in high-density scenarios, and energy utilization is suboptimal in low-density scenarios, resulting in system performance that cannot meet diverse needs. Therefore, a multi-user access method that can flexibly select incentives based on tag density to optimize system performance is urgently needed. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a passive network multi-user access method and related devices, which can flexibly select the incentive mode according to the tag density and optimize the system performance.

[0005] To achieve the above object, the present invention discloses a passive network multi-user access method, comprising:

[0006] The reader detects the tag density in the network in real time to determine the scene type;

[0007] When the average number of access users is less than the spreading code capacity, a one-time high-power excitation access is adopted;

[0008] When the average number of access users is greater than the spreading code capacity, a hierarchical incentive strategy is adopted for access.

[0009] The passive network multi-user access method of the present invention is further improved in that:

[0010] Furthermore, the process of implementing the hierarchical incentive strategy is as follows:

[0011] The reader broadcasts an RF signal with a power of P1 to stimulate the first layer of tags at a closer distance. After receiving the RF excitation signal, the first layer of tags modulates their own ID information onto the RF excitation signal, and then reflects it to the reader through the antenna. The reader parses the signal, obtains the ID information of the first layer of tags, and completes the discovery of the first layer of tags. The reader sends a silent command to control the first layer of tags to enter the silent state. Then the reader broadcasts an RF signal with a power of P2 to stimulate the second layer of tags at a farther distance. The above tag response and identification process is repeated until all layers of tags are accessed.

[0012] Furthermore, P2>P1.

[0013] Furthermore, the process of one-time high-power incentive access is as follows:

[0014] The reader directly broadcasts a high-power radio frequency signal to stimulate all tags within range at once; the tags respond synchronously and send their ID information. The reader identifies the tags through a spread spectrum code mechanism that uses chip energy detection.

[0015] Furthermore, the method further includes: when access fails, re-accessing is performed using a retransmission and power adjustment mechanism.

[0016] Furthermore, the process of re-accessing by using the retransmission and power adjustment mechanism is as follows:

[0017] When access fails, the retransmission power is dynamically adjusted based on the signal power of the initial detection; when the initial detection power is low and unsuccessful, high-power retransmission is used; when the power is high but unsuccessful, low-power retransmission is used; when the power is extremely low, it is determined that there is no user on the channel and the access attempt is stopped; at the same time, a different spreading code is used during retransmission.

[0018] Furthermore, the one-time high-power incentive access process further includes:

[0019] According to the signal strength P received by the tag r , divide all labels into strong signal group and weak signal group;

[0020] Priorities are assigned to the tags in the strong signal group and the weak signal group, and the tags are sent according to the priorities.

[0021] The present invention discloses a passive network multi-user access system, comprising:

[0022] The judgment module is used by the reader to detect the tag density in the network in real time to determine the scene type;

[0023] The first access module is configured to use a one-time high-power excitation access when the average number of access users is less than the spread spectrum code capacity;

[0024] The second access module is used to adopt a hierarchical incentive strategy for access when the average number of access users is greater than the spreading code capacity.

[0025] The present invention discloses a computer device, comprising a memory, a processor and a computer program stored in the memory and capable of running on the processor. When the processor executes the computer program, the steps of the passive network multi-user access method are realized.

[0026] The present invention discloses a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the passive network multi-user access method are implemented.

[0027] The present invention has the following beneficial effects:

[0028] During specific operation, the passive network multi-user access method and related devices described in the present invention adopt a one-time high-power excitation access when the average number of access users is less than the spread spectrum code capacity; and adopt a layered excitation strategy access when the average number of access users is greater than the spread spectrum code capacity. The excitation strategy is dynamically switched through over-density detection. Layered excitation in high-density scenarios avoids signal conflicts, and one-time high-power excitation in low-density scenarios improves efficiency, thereby meeting the needs of multiple scenarios such as smart logistics, factories, and retail.

[0029] Furthermore, the present invention combines layered excitation with silent instructions to isolate identified tags layer by layer, reducing cross-layer interference; the retransmission code switching mechanism reduces random access conflicts and accelerates transmission convergence.

[0030] Furthermore, the present invention avoids secondary power consumption in low-density scenarios and controls power in layers in high-density scenarios, thereby reducing the power consumption of readers and tags while ensuring the recognition rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0032] Figure 1 Schematic diagram of the composition of a passive multi-user tag network in an embodiment of the present invention;

[0033] Figure 2 Schematic diagram of coverage of signals with different power levels according to an embodiment of the present invention;

[0034] Figure 3 Schematic diagram of a frame structure in an embodiment of the present invention;

[0035] Figure 4 Schematic diagram of label priority division in an embodiment of the present invention. DETAILED DESCRIPTION

[0036] 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 them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0037] In the description of the present invention, it is to be understood that the terms “include” and “comprise” indicate the presence of the described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0038] It should also be understood that the terms used in the present specification are only for the purpose of describing particular embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0039] It should be further understood that the term "and / or" as used in the present specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0040] It should be understood that although the terms "first," "second," and "third" may be used to describe preset ranges in embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are merely used to distinguish one preset range from another. For example, without departing from the scope of embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0041] The word "if," as used herein, may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to the determination" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)," depending on the context.

[0042] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0043] The accompanying drawings illustrate various schematic diagrams of structures according to embodiments disclosed herein. These figures are not drawn to scale; for clarity, some details are exaggerated and some details may be omitted. The shapes of the various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations. Those skilled in the art may design regions / layers with different shapes, sizes, and relative positions as needed.

[0044] The passive network multi-user access method of the present invention comprises the following steps:

[0045] Scenario detection and power strategy selection: The reader detects the tag density in the network in real time and compares it with a preset threshold to determine the scenario type. When the average number of connected users is less than the spreading code capacity, a one-time high-power excitation access strategy is used. When the average number of connected users is greater than the spreading code capacity, a tiered excitation strategy is used.

[0046] The access process of the hierarchical excitation strategy is as follows: in a high-density scenario, the reader broadcasts an RF signal with a power of P1 to excite the first layer of tags at a relatively close distance; after receiving the RF excitation signal, the first layer of tags modulates their own ID information onto the RF excitation signal, which is then reflected to the reader via the antenna. The reader parses the signal, obtains the ID information of the first layer of tags, and completes the discovery of the first layer of tags; the reader sends a silent command to control the first layer of tags to enter a silent state; then the reader broadcasts an RF signal with a power of P2 (P2>P1) to excite the second layer of tags at a relatively long distance, and repeats the above tag response and identification process until all layers of tags are accessed;

[0047] The one-time high-power excitation access process is as follows: In low-density scenarios, the reader directly broadcasts a high-power RF signal to excite all tags within range at once. The tags respond synchronously, sending their ID information. The reader identifies the tags through a spread spectrum code mechanism that uses chip energy detection and an AND operation between multi-user spread spectrum codes.

[0048] Retransmission and power adjustment mechanism: When access fails, the retransmission power is dynamically adjusted based on the signal power of the initial detection. If the initial detection power is low and unsuccessful, high-power retransmission is used. If the power is high but unsuccessful, low-power retransmission is used. If the power is extremely low, it is determined that there are no users on the channel and the access attempt is stopped. At the same time, different spreading codes are used during retransmission.

[0049] In this embodiment, the one-time high-power incentive access process further includes:

[0050] Power packet communication: The tag receives the signal based on its strength P. r , divided into “strong signal group” and “weak signal group”; when P r <P th , the tag is divided into a "weak signal group", blocking P r ≥P th , the tags are divided into "strong signal groups" and the strong signal groups are processed first;

[0051] Priority grading within a group: randomly generate a priority parameter P i , P i =random(1,2 k+1 ), where k is the number of retransmissions; within each group of tags, time slots are allocated according to priority, with high-priority tags being sent first;

[0052] Multi-user encoding and concurrent decoding: The tag uses a spread spectrum code to encode and modulate the ID information and sends the signal to the reader. The reader uses a multi-user decoding algorithm to separate the signals, decode the signals one by one, extract the tag's ID information, and store it.

[0053] Retransmission processing: When the reader fails to decode, the retransmission power is adjusted according to the spread spectrum code detection power; the P is adjusted according to the signal group conflict situation. th Threshold power; adjust the number of retransmissions. When retransmitting, the number of retransmissions k increases by 1, and the priority parameter P i The range is expanded and the number of labels allocated to a single time slot is reduced; a code change strategy is adopted to select different codes from the spread spectrum code for transmission.

[0054] In this embodiment, the reader detects the tag density in a specific manner by monitoring the number of tags connected to the network in real time and comparing it with the preset spreading code capacity to determine the tag density scenario type.

[0055] In this embodiment, in the layered excitation access process, the excitation power of each layer of tags increases in sequence according to the distance, and the difference between the excitation powers of two adjacent layers of tags is set according to the actual application scenario.

[0056] In this embodiment, during the retransmission process, P is adjusted. th When the strong signal group conflicts seriously, increase P th , reduce the number of tags in the group; when the weak signal group conflicts seriously, reduce P th , reduce the number of labels in the group.

[0057] Example 1

[0058] This embodiment is applied to smart logistics warehouse scenarios, specifically high-density scenarios.

[0059] Scenario detection: When goods arrive in a warehouse in batches, the reader detects that the tag density is higher than the threshold, which triggers the hierarchical incentive strategy.

[0060] The first level of incentives: Figure 2 As shown in the figure, the reader broadcasts an RF signal with a power of P1. After receiving the RF excitation signal, each tag in the first layer modulates its ID information onto the RF signal, which is then reflected back to the reader via the antenna. The reader then obtains the ID information of the first-layer tags and completes the discovery of the first-layer tags. The reader parses the ID information, records it, and sends a silencing command to silence the first-layer tags.

[0061] Second-layer excitation: The reader broadcasts a radio frequency signal with a power of P2 (P2>P1) to excite shelf tags at a farther distance (the second layer), repeating the recognition and silence process until all tags are connected.

[0062] Example 2

[0063] This embodiment is used in small retail inventory scenarios, specifically low-density scenarios.

[0064] Scene detection: There are fewer items in retail stores, and the tag density is lower than the threshold, so a one-time high-power excitation is used.

[0065] One-time high-power excitation: The reader broadcasts a high-power signal, covering the entire tag network and stimulating all tags.

[0066] The frame structure of the signal is as follows Figure 3 As shown, the instruction control field indicates that the current signal is an excitation signal to excite the entire tag network. th The Threshold Power field indicates the power threshold of the label group, which is used for subsequent label grouping. The Retransmission Count k field indicates the number of retransmissions after failed decoding, which is used for subsequent label priority allocation and label synchronization response.

[0067] Power packet communication: The tag receives the signal based on its strength P. r , divided into "strong signal group" and "weak signal group". r <P th , the tags are divided into “weak signal groups”, if P r ≥P th , the tag is divided into a "strong signal group". The strong signal group is processed first to reduce the risk of weak signals being masked.

[0068] Priority grading within a group: randomly generate a priority parameter P i for:

[0069] P i =random(1,2 k+1 )

[0070] Where k = number of retransmissions, Figure 4 The figure shows the priority sorting of tags. The strong signal group has a higher priority than the weak signal group. Within each group of tags, time slots are allocated according to the priority, and high-priority tags are sent first.

[0071] Multi-user encoding and concurrent decoding: The tag uses spread spectrum code to encode and modulate ID information and sends the signal to the reader. The reader uses a multi-user decoding algorithm to separate the signals, decode the signals one by one, extract the tag ID information and store it.

[0072] The retransmission process is as follows:

[0073] When the reader fails to decode, the retransmission power is adjusted based on the spread spectrum code detection power. Low spread spectrum code detection power and access failure indicate that the user is far away, so a high-power signal is used for retransmission. High spread spectrum code detection power but transmission failure indicates that the user is close, so a low-power signal is used for retransmission. Extremely low power indicates that no user is connected to the channel.

[0074] Adjust P according to the signal group conflict situation th Threshold power, strong signal group conflicts are serious, increase P th , reduce the number of tags in the group; weak signal group conflicts are serious, reduce P th , reduce the number of labels in the group.

[0075] Adjust the number of retransmissions. When retransmitting, the number of retransmissions k is increased by 1 (the initial value is 0), and the priority parameter P i The scope is expanded to: P i =random(1,2 k+1 ), the number of labels allocated to a single time slot is reduced, reducing the difficulty of decoding.

[0076] By adopting a code-changing strategy, different codes are selected from the spread spectrum codes for transmission, and codes are randomly changed after transmission conflicts. This can take advantage of the reduction in remaining users to reduce the probability of conflicts, accelerate transmission convergence, and improve communication efficiency.

[0077] Example 3

[0078] The passive network multi-user access system of the present invention comprises:

[0079] The judgment module is used by the reader to detect the tag density in the network in real time to determine the scene type;

[0080] The first access module is configured to use a one-time high-power excitation access when the average number of access users is less than the spread spectrum code capacity;

[0081] The second access module is used to adopt a hierarchical incentive strategy for access when the average number of access users is greater than the spreading code capacity.

[0082] The division of modules in the embodiments of the present application is illustrative and is merely a logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in the various embodiments of the present application may be integrated into a single processor, or may exist physically separately, or two or more modules may be integrated into a single module. The aforementioned integrated modules may be implemented in the form of hardware or software functional modules.

[0083] Example 4

[0084] A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of the passive network multi-user access method are implemented, for example, including: a reader detects the tag density in the network in real time to determine the scenario type; when the average number of accessing users is less than the spreading code capacity, a one-time high-power incentive access strategy is used; when the average number of accessing users is greater than the spreading code capacity, a hierarchical incentive strategy is used. The memory may include internal memory, such as a high-speed random access memory, or may also include non-volatile memory, such as at least one disk storage device. The processor, network interface, and memory are interconnected via an internal bus, which may be an industry standard architecture bus, a peripheral component interconnect standard bus, an extended industry standard architecture bus, etc. The bus may be classified as an address bus, a data bus, a control bus, etc. The memory is used to store programs. Specifically, the programs may include program code, which includes computer operating instructions. The memory may include internal memory and non-volatile memory, and provides instructions and data to the processor.

[0085] Example 5

[0086] A computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the passive network multi-user access method, for example, including: a reader detects the tag density in the network in real time to determine the scenario type; when the average number of access users is less than the spread spectrum code capacity, a one-time high-power incentive access is adopted; when the average number of access users is greater than the spread spectrum code capacity, a hierarchical incentive strategy is adopted for access. Specifically, the computer-readable storage medium includes, but is not limited to, volatile memory and / or non-volatile memory. The volatile memory may include random access memory and / or cache memory, etc. The non-volatile memory may include read-only memory, hard disk, flash memory, optical disk, magnetic disk, etc.

[0087] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present application may take the form of a computer program product implemented on one or more computer-usable storage media containing computer-usable program code.

[0088] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0089] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0090] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0091] Those skilled in the art will readily identify other embodiments of the present invention after considering the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.

[0092] It should be understood that the present invention is not limited to the exact construction described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

[0093] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A passive network multi-user access method, characterized in that: include: The reader detects the tag density in the network in real time to determine the scene type; When the average number of access users is less than the spreading code capacity, a one-time high-power excitation access is adopted; When the average number of access users is greater than the spreading code capacity, a hierarchical incentive strategy is adopted for access.

2. The passive network multi-user access method according to claim 1, characterized in that: The process of accessing the hierarchical incentive strategy is as follows: The reader broadcasts an RF signal with a power of P1 to stimulate the first layer of tags at a closer distance. After receiving the RF excitation signal, the first layer of tags modulates their own ID information onto the RF excitation signal, and then reflects it to the reader through the antenna. The reader parses the signal, obtains the ID information of the first layer of tags, and completes the discovery of the first layer of tags. The reader sends a silent command to control the first layer of tags to enter the silent state. Then the reader broadcasts an RF signal with a power of P2 to stimulate the second layer of tags at a farther distance. The above tag response and identification process is repeated until all layers of tags are accessed.

3. The passive network multi-user access method according to claim 2, characterized in that: P2>P1.

4. The passive network multi-user access method according to claim 1, characterized in that: The process of one-time high-power incentive access is as follows: The reader directly broadcasts a high-power radio frequency signal to stimulate all tags within range at once; the tags respond synchronously and send their ID information. The reader identifies the tags through a spread spectrum code mechanism that uses chip energy detection.

5. The passive network multi-user access method according to claim 1, characterized in that: Also includes: When access fails, retransmission and power adjustment mechanisms are used to re-access.

6. The passive network multi-user access method according to claim 5, characterized in that: The process of re-accessing by using the retransmission and power adjustment mechanism is as follows: When access fails, the retransmission power is dynamically adjusted based on the signal power of the initial detection; when the initial detection power is low and unsuccessful, high-power retransmission is used; when the power is high but unsuccessful, low-power retransmission is used; when the power is extremely low, it is determined that there is no user on the channel and the access attempt is stopped; at the same time, a different spreading code is used during retransmission.

7. The passive network multi-user access method according to claim 4, characterized in that: The one-time high-power incentive access process also includes: According to the signal strength P received by the tag r , divide all labels into strong signal group and weak signal group; Priorities are assigned to the tags in the strong signal group and the weak signal group, and the tags are sent according to the priorities.

8. A passive network multi-user access system, characterized in that: include: The judgment module is used by the reader to detect the tag density in the network in real time to determine the scene type; The first access module is configured to use a one-time high-power excitation access when the average number of access users is less than the spread spectrum code capacity; The second access module is used to adopt a hierarchical incentive strategy for access when the average number of access users is greater than the spreading code capacity.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the passive network multi-user access method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the passive network multi-user access method according to any one of claims 1 to 7 are implemented.

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