A passive Internet of Things access method and device, electronic equipment and storage medium

Abstract

Embodiments of the present application disclose a kind of passive Internet of Things access method, device, electronic equipment and storage medium, involve wireless communication and Internet of Things technical field, wherein, the method comprises: the copy number of equipment request message is probabilistic sampling allocation to corresponding response time slot and subchannel, the degree of 1 resource block is demodulated and extracted random identification and seed, seed is obtained by inverse mapping copy location, and the mixed signal of collision resource block is stripped layer by layer.Demodulated unscheduled equipment number reaches subchannel number when carrying out subchannel allocation and load transmission authorization, and cancel pending copy, corresponding resource block node is synchronously erased.The received signal power of each subchannel is continuously monitored, and when it is lower than the idle determination threshold in continuous multiple response opportunities, the subsequent response opportunity is truncated.The present application solves the problem of sharp decline in throughput when mass equipment burst access in prior art, and the fixed frame length has no adaptive truncation capability.

Description

Technical Field

[0001] This invention relates to the fields of wireless communication and Internet of Things (IoT) technology, and in particular to a passive IoT access method, device, electronic device, and storage medium. Background Technology

[0002] With the development of 6G communication technology, passive IoT, due to its extremely low cost and low power consumption, is widely used in scenarios requiring massive device connectivity, such as warehousing and logistics, asset tracking, and smart manufacturing. In these scenarios, when a reader or base station initiates an inventory check, a massive number of passive devices are simultaneously activated and attempt to connect to the network, generating extreme bursts of traffic.

[0003] However, existing random access mechanisms based on slotted ALOHA face numerous challenges in handling such scenarios. In traditional single-round request collection mechanisms, the reader collects access requests from devices within only one time slot. The number of devices successfully demodulated is often far less than the number of available sub-channels, resulting in a large number of sub-channels remaining idle during subsequent long-duration data transmission phases, causing severe waste of time and frequency resources. Simultaneously, traditional slotted ALOHA completely lacks collision recovery capabilities. When multiple devices concurrently send requests on the same resource block, signal aliasing prevents the reader from demodulating any device information. Conflicting devices can only wait for the next frame to re-initiate access, easily leading to continuous collision deadlocks during massive terminal bursts of access, causing a precipitous drop in system throughput.

[0004] Furthermore, some existing collision mitigation schemes require devices to carry explicit location pointers in their request messages to indicate the distribution of their multiple replicas within time-frequency resources. This leads to a sharp increase in physical layer signaling overhead and an extremely low proportion of effective data, severely conflicting with the physical constraints of low power consumption and short packet transmission for passive devices. Fixed frame length mechanisms lack the ability to perceive the physical state of the channel and adaptively truncate. Under unknown device scale, they blindly traverse all preset response opportunities, consuming the full frame length regardless of whether there are still devices transmitting in the channel, resulting in massive amounts of invalid waiting time.

[0005] Therefore, there is an urgent need for a passive IoT access method that can maximize multi-channel utilization, achieve efficient collision recovery, reduce physical layer overhead, and adaptively truncate invalid frame lengths. Summary of the Invention

[0006] The present invention provides a passive Internet of Things (IoT) access method to address the problems of severe resource idleness, sharp drop in throughput during sudden access by a large number of devices, and lack of adaptive truncation capability for fixed frame lengths in existing technologies. The technical solution is as follows: According to one aspect of the present invention, a passive Internet of Things (IoT) access method includes: probabilistically sampling the number of replicas of request messages from passive devices using an irregular degree distribution multinomial; mapping a pseudo-random number seed to a global resource block index using a pseudo-random number generator; allocating multiple request messages from each passive device to corresponding response slots and sub-channels; receiving and buffering the request messages by successive triggering of response opportunities; demodulating resource blocks with a degree of 1 in the buffered signal to extract random identifiers and seeds; obtaining replica locations by inverse mapping the seeds using a pseudo-random number generator; and according to the... The replica location peels away the mixed signal of the colliding resource block layer by layer; the demodulated but unscheduled passive devices are counted through the demodulation buffer pool, and when the number of sub-channels is reached, a specified number of passive devices are allocated sub-channels and authorized for payload transmission, and the pending request message replicas of the passive devices are canceled, and the resource block nodes corresponding to the scheduled passive devices are erased simultaneously; the received signal power of each sub-channel is continuously monitored through the physical layer energy detector, and when all sub-channels are below the idle determination threshold within multiple consecutive response opportunities, the subsequent response opportunity triggering process of the current frame is forcibly truncated and terminated through the MAC layer interrupt instruction.

[0007] In one embodiment, the probability sampling of the number of replicas of the request message of the passive device through the irregular degree distribution multinomial is achieved through the following steps: the number of replicas of the request message to be sent by each passive device in the current frame is determined by probability sampling according to the preset irregular degree distribution multinomial, and written as a degree indicator field into the physical layer payload of each request message replica; the irregular degree distribution multinomial defines the probability distribution of the passive device selecting different numbers of replicas.

[0008] In one embodiment, the allocation of multiple request messages from each passive device to corresponding response slots and sub-channels is achieved by mapping the pseudo-random number seed to the global resource block index using a pseudo-random number generator through the following steps: A random sequence is generated using a hardware random number generator, thermal noise, or internal counter built into the passive device; the random sequence serves as a temporary dynamic identifier for the passive device within the current frame and a pseudo-random number seed for generating the resource mapping pattern; the pseudo-random number seed is used as an initialization vector input to the pseudo-random sequence generator to generate non-repeating pseudo-random integers corresponding to the number of replicas in a resource pool ranging from 1 to the total number of global resource blocks, serving as the absolute index of the global resource block for each replica of the passive device; if duplicate values ​​appear in the generated pseudo-random integers, the next random number is extracted using a linear congruent or shift register, and a two-dimensional time-frequency calculation is performed on each of the absolute indices of the global resource blocks to determine the corresponding response slot sequence number and sub-channel number, and the resource mapping set is stored in a local cache.

[0009] In one embodiment, the request message is received and buffered by successive triggering of response opportunities, and the random identifier and seed of the resource block with a degree of 1 in the buffered signal are demodulated and extracted through the following steps: a time slot triggering instruction is sent sequentially; within the duration of each response opportunity, a request message carrying the pseudo-random number seed and the degree indicator field is sent according to the response time slot sequence number and sub-channel number corresponding to the request message of the passive device; during each response opportunity, the mixed signal of concurrent request messages is received on each of the sub-channels simultaneously; all received signals are stored in the baseband buffer; all baseband buffers are scanned; collision-free resource blocks with a degree of 1 are searched and located, and demodulated to extract the pseudo-random number seed and degree indicator.

[0010] In one embodiment, the replica position is obtained by inverse mapping the seed using a pseudo-random number generator. The mixed signal of the colliding resource block is then stripped layer by layer based on the replica position through the following steps: The demodulated pseudo-random number seed is used as an initialization vector to be input into the pseudo-random sequence generator. From a resource pool of 1 to the total number of global resource blocks, the absolute index of all global one-dimensional resource blocks of the passive device in this frame is generated to obtain the replica position. The replica position is compared with the actual received signal. For the colliding resource block, the physical layer waveform component of the passive device in the resource block is reconstructed based on the demodulated signal of the passive device and then subtracted from the mixed received signal. This process is repeated until no new valid decoding can be generated.

[0011] In one embodiment, the demodulated but unscheduled passive devices are counted through a demodulation buffer pool. When the number of sub-channels is reached, a specified number of passive devices are allocated sub-channels and granted payload transmission authorization. The pending request message copies of the passive devices are canceled, and the resource block nodes corresponding to the scheduled passive devices are simultaneously erased. This is achieved through the following steps: All valid random identifiers of passive devices in each response opportunity are uniformly stored in the demodulation buffer pool in memory, and the number of demodulated but unscheduled devices is counted in real time, continuously monitoring the number of devices. When the number of devices reaches or exceeds the total number of sub-channels, the triggering command for sending the response opportunity is paused, and a scheduling confirmation message carrying a random identifier is issued. The devices are implicitly mapped to the physical layer sub-channels according to the order of the random identifiers. At the same time, all request message copies planned to be sent by the scheduled passive devices in subsequent response opportunities of the current frame are canceled, and all resource block nodes corresponding to the scheduled passive devices are erased in the interference cancellation bipartite graph cache used to characterize the mapping relationship between resource blocks and devices.

[0012] In one embodiment, the received signal power of each sub-channel is continuously monitored by a physical layer energy detector. When all sub-channels are below the idle determination threshold within multiple consecutive response opportunities, the subsequent response opportunity triggering process of the current frame is forcibly truncated and terminated by a MAC layer interrupt command. This is achieved through the following steps: During the duration of each response opportunity, the received signal power of each sub-channel is continuously detected by the physical layer energy detector. The received energy of each sub-channel is compared with a preset idle determination noise floor threshold to determine whether each sub-channel carries a valid backscatter signal. When the received energy of all sub-channels within a response opportunity is below the idle determination threshold, the response opportunity is recorded as a physical idle. When a set number of physical idles occur consecutively, it is determined that all passive devices within the current coverage area have completed scheduling and entered a sleep state. The subsequent response opportunity triggering process of the current frame is forcibly truncated and terminated by a MAC layer interrupt command, and no more time slot trigger commands are issued. After the current frame is truncated and terminated, if there are still successfully demodulated passive devices in the demodulation buffer pool, a corresponding scheduling confirmation message is issued to complete the payload data transmission of all passive devices.

[0013] According to one aspect of the present invention, a passive Internet of Things (IoT) access device includes: a frame initialization and resource mapping module, configured to perform probability sampling on the number of replicas of request messages from passive devices using an irregular degree distribution multinomial, perform mapping calculation on a pseudo-random number seed and a global resource block index using a pseudo-random number generator, and allocate multiple request messages from each passive device to corresponding response slots and sub-channels; and a multi-round collection and interference cancellation module, configured to receive and buffer the request messages by successive triggering of response opportunities, demodulate and extract random identifiers and seeds from resource blocks with a degree of 1 in the buffered signals, perform inverse mapping on the seeds using a pseudo-random number generator to obtain replica locations, and, according to the... The replica location peels away the mixed signals of the colliding resource blocks layer by layer; the full-load scheduling and replica circuit breaker module is used to count the demodulated but unscheduled passive devices through the demodulation buffer pool. When the number of sub-channels is reached, the module allocates sub-channels and grants payload transmission authorization to a specified number of passive devices, cancels the pending request message replicas of the passive devices, and simultaneously erases the resource block nodes corresponding to the scheduled passive devices; the physical idle and early termination module is used to continuously monitor the received signal power of each sub-channel through the physical layer energy detector. When all sub-channels are below the idle determination threshold within multiple consecutive response opportunities, the module forcibly truncates and terminates the subsequent response opportunity triggering process of the current frame through the MAC layer interrupt instruction.

[0014] According to one aspect of the present invention, an electronic device includes at least one processor and at least one memory, wherein computer-readable instructions are stored on the memory; the computer-readable instructions are executed by one or more of the processors to enable the electronic device to implement the passive Internet of Things access method as described above.

[0015] According to one aspect of the present invention, a storage medium has computer-readable instructions stored thereon, which are executed by one or more processors to implement the passive Internet of Things access method as described above.

[0016] The beneficial effects of the technical solution provided by this invention are: In the above technical solution, this invention uses an irregular degree distribution multinomial to probabilistically sample the number of replicas of request messages from passive devices, and uses a pseudo-random number generator to map the pseudo-random number seed to the global resource block index. This allocates multiple request messages from each device to corresponding response slots and sub-channels, achieving implicit representation of device replica locations and low-overhead resource mapping. Based on this, by sequentially triggering response opportunities to receive buffered request messages, the invention demodulates and extracts random identifiers and seeds from resource blocks with a degree of 1 in the buffered signal. The pseudo-random number generator then performs inverse mapping of the seed to obtain the replica location. Based on the replica location, the mixed signals of colliding resource blocks are peeled off layer by layer, achieving online recovery of collision signals. Subsequently, the demodulated but unscheduled devices are counted through a demodulation buffer pool. When the sub-channel number is reached, a specified number of devices are allocated sub-channels and payload transmission authorization is granted. The pending replicas of the scheduled devices are canceled, and the corresponding resource block nodes are simultaneously erased, achieving full-load scheduling of multi-channel resources and dynamic channel cleanup. Finally, the received signal power of each sub-channel is continuously monitored by a physical layer energy detector. When all sub-channels are below the idle threshold within multiple consecutive response opportunities, the subsequent response opportunity triggering process of the current frame is forcibly truncated and terminated by a MAC layer interrupt command, thus achieving adaptive truncation of invalid frame lengths. This invention effectively solves the problems in the prior art, such as single-round request collection leading to difficulty in fully loading sub-channels, lack of collision recovery capability in traditional time-slot ALOHA, severe redundancy in physical layer signaling caused by explicit position pointers, and massive invalid waiting time due to lack of adaptive truncation capability in fixed frame lengths. It significantly improves the efficiency of large-scale random access in multi-channel passive IoT. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating a passive Internet of Things (IoT) access method according to an exemplary embodiment; Figure 2 This is a schematic diagram of a source Internet of Things tag access system as illustrated in an exemplary embodiment; Figure 3 Performance simulation diagrams of existing technologies and the present invention at different frame lengths L in an application scenario; Figure 4 Simulation diagram of the performance limits of existing technologies and the present invention under different numbers of active tags in an application scenario; Figure 5 This is a block diagram illustrating a passive Internet of Things access device according to an exemplary embodiment; Figure 6 This is a hardware structure diagram of an electronic device according to an exemplary embodiment; Figure 7 This is a block diagram illustrating an electronic device according to an exemplary embodiment. Detailed Implementation

[0019] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0020] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this disclosure means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or wireless coupling. The term “and / or” as used herein includes all or any units and all combinations of one or more associated listed items.

[0021] This invention provides a passive IoT access method. It achieves low-overhead resource allocation for multiple requests through irregular replica distribution and pseudo-random implicit mapping; it achieves layer-by-layer collision signal stripping and channel purification through online interference cancellation and replica circuit breaking mechanisms; it achieves full-load transmission of multiple channel resources through counting scheduling of the demodulation buffer pool; and it achieves adaptive frame length truncation through physical layer energy sensing. This solves the problems of idle channel resources, lack of collision recovery, high signaling overhead, and long invalid waiting times in existing technologies. This passive IoT access method is applicable to passive IoT access devices, which can be electronic devices. The passive IoT access method in this invention can be applied to various scenarios, such as self-searching of LPDDR chip timing boundaries.

[0022] Please see Figure 1 This invention provides a passive Internet of Things (IoT) access method applicable to electronic devices.

[0023] In the following method embodiments, for ease of description, the execution subject of each step of the method is an electronic device, but this does not constitute a specific limitation.

[0024] like Figure 1 As shown, the method may include the following steps: Step 110: Probabilistically sample the number of copies of the request message of the passive device using an irregular degree distribution multinomial, and use a pseudo-random number generator to map the pseudo-random number seed to the global resource block index, and allocate the multiple request messages of each passive device to the corresponding response time slot and sub-channel.

[0025] In one possible implementation, the number of copies of the request message to be sent by each passive device in this frame is determined by probability sampling based on a preset irregular degree distribution multinomial, and written as a degree indicator field into the physical layer payload of each request message copy.

[0026] In one possible implementation, a random sequence is generated using a hardware random number generator, thermal noise, or internal counter built into the passive device. A pseudo-random number seed is used as an initialization vector and input into the pseudo-random sequence generator to generate a number of unique pseudo-random integers corresponding to the number of global resource blocks from a resource pool of 1 to the total number of global resource blocks. These unique pseudo-random integers serve as the absolute indexes of the global resource blocks for each replica of the passive device. If duplicate values ​​appear in the generated pseudo-random integers, the next random number is extracted using a linear congruent or shift register. Two-dimensional time-frequency calculations are performed on the absolute indices of each global resource block to determine the corresponding response time slot sequence number and sub-channel number. The resource mapping set is then stored in the local cache.

[0027] The irregularity distribution multinomial defines the probability distribution of the passive device selecting different numbers of replicas. The random sequence serves as a temporary dynamic identifier for the passive device within the current frame and as a pseudo-random number seed for generating the resource mapping pattern.

[0028] Specifically, the reader calculates the total number of response opportunities L and the number of sub-channels K for the initial frame based on the currently estimated total number of devices to be accessed. It then broadcasts these frame parameters to all passive devices within the coverage area via paging messages, while simultaneously continuously transmitting continuous wave signals to provide power and uplink backscatter carriers to the passive devices. Each passive device enters an active state after being woken up.

[0029] Furthermore, each passive device determines the total number d of request message copies it needs to send in this frame through probability sampling based on the system's preset irregularity distribution polynomial Ω(x). This polynomial defines the probability distribution of devices choosing different numbers of copies, so that most devices choose fewer copies to reduce the overall collision probability, while a minority of devices choose more copies to increase their probability of appearing in collision-free resource blocks, thereby providing sufficient "seed" nodes for subsequent interference cancellation.

[0030] Furthermore, each passive device uses its built-in hardware random number generator to generate a 16-bit random sequence, which serves as both a temporary dynamic identifier and a pseudo-random number seed for the device within the current frame. The device uses this seed as an initialization vector input to the pseudo-random sequence generator, generating d unique pseudo-random integers from a global resource pool ranging from 1 to L×K. These integers are used as absolute indices for the global resource blocks of each replica. Two-dimensional time-frequency calculations are then used to determine the response slot number and sub-channel number corresponding to each replica, and the resource mapping set is stored in the local cache.

[0031] In the above process, the embodiments of the present invention replace the traditional explicit position pointer with the implicit mapping mechanism of pseudo-random number seed, so that the physical layer payload of the request message only needs to carry a 16-bit random identifier and a 2-bit degree indicator, totaling 18 bits, which greatly reduces the uplink transmission overhead of passive devices and provides a low-power premise for subsequent online continuous interference cancellation.

[0032] Step 120: The request message is received and cached by successive triggering of the response opportunity, and the random identifier and seed are extracted from the resource block with a density of 1 in the cache signal. The replica position is obtained by inverse mapping the seed through a pseudo-random number generator, and the mixed signal of the colliding resource block is stripped layer by layer according to the replica position.

[0033] In one possible implementation, a time slot trigger command is sent sequentially. During the duration of each response opportunity, a request message carrying a pseudo-random number seed and degree indicator field is sent according to the response time slot sequence number and sub-channel number corresponding to the request message of the passive device. During each response opportunity, the mixed signal of concurrent request messages is received on each sub-channel. All received signals are stored in the baseband buffer. All baseband buffers are scanned to search for and locate the collision-free resource block with a resource block degree of 1 and demodulate it to extract the pseudo-random number seed and degree indicator.

[0034] In one possible implementation, the demodulated pseudo-random number seed is used as the initialization vector input to the pseudo-random sequence generator. In a resource pool ranging from 1 to the total number of global resource blocks, the absolute index of all global one-dimensional resource blocks of the passive device in this frame is generated to obtain the replica position. The replica position is compared with the actual received signal. For resource blocks that collide, the physical layer waveform components of the passive device in the resource block are reconstructed based on the demodulated passive device signal and then subtracted from the mixed received signal. This process is repeated until no new valid decoding can be generated.

[0035] Specifically, the reader sends time slot trigger commands one by one to initiate response opportunities and controls the advancement of each response opportunity within the frame. Each passive device searches its local resource mapping set to see if the current response opportunity is its pre-selected transmission time slot. If so, it sends a request message carrying a random identifier and degree indication on the sub-channel corresponding to that time slot.

[0036] Furthermore, in each response opportunity, the reader simultaneously receives concurrent request message mixed signals on K sub-channels and stores all received signals in the baseband buffer. If the number of demodulated but not yet scheduled devices collected in the current round is less than K, the reader issues a backoff trigger command. Upon receiving the command, the unscheduled device decrements its internal backoff counter by 1. Devices with counters set to zero send requests in the next response opportunity, thus achieving multiple rounds of continuous collection.

[0037] Furthermore, the reader scans all historical receive buffers, searches for collision-free resource blocks with a resource block degree of exactly 1, demodulates them, and extracts the random identifier and pseudo-random number seed of the corresponding passive device. The reader uses the demodulated pseudo-random number seed as an initialization vector to input into the pseudo-random sequence generator, generating absolute indices of all global resource blocks for the device within the current frame in the global resource pool, thus completing the inverse mapping calculation of the replica location.

[0038] Furthermore, the reader compares the calculated copy location with the actual received signal. For resource blocks that collide, it reconstructs the physical layer waveform component of the device in the colliding resource block using the demodulated device signal and channel estimation, and subtracts it from the mixed received signal. This process is iterated until no new valid decoding can be generated. All newly demodulated or recovered valid random identifiers are stored in the demodulation buffer.

[0039] In the above process, the embodiments of the present invention expose and recover the signals of the hidden devices that could not be demodulated due to collisions by peeling off layer by layer through the online continuous interference cancellation mechanism. This completely breaks through the bottleneck of the traditional time slot ALOHA's complete lack of collision recovery capability under heavy load. At the same time, the multi-round collection mechanism provides sufficient signal buffering and iteration opportunities for interference cancellation.

[0040] Step 130: Count the demodulated but unscheduled passive devices through the demodulation buffer pool. When the number of sub-channels is reached, allocate sub-channels and grant payload transmission authorization to a specified number of passive devices, cancel the pending request message copies of the passive devices, and simultaneously erase the resource block nodes corresponding to the scheduled passive devices.

[0041] In one possible implementation, all valid passive device random identifiers for each response opportunity are uniformly stored in a demodulation buffer pool in memory, and the number of demodulated but not yet scheduled devices is counted in real time, continuously monitoring the number of devices; when the number of devices reaches or exceeds the total number of sub-channels, the triggering command for sending response opportunities is suspended, and a scheduling confirmation message carrying random identifiers is issued, implicitly mapping each device to a physical layer sub-channel according to the order of the random identifiers.

[0042] In one possible implementation, all copies of request messages that the scheduled passive device plans to send in subsequent response opportunities of the current frame are cancelled, and all resource block nodes corresponding to the scheduled passive device are erased in the interference cancellation bipartite graph cache used to characterize the mapping relationship between resource blocks and devices.

[0043] Specifically, the reader monitors in real time the number of demodulated but not yet scheduled devices in the demodulation buffer pool. When this number is less than the number of sub-channels K, the reader refuses to initiate the payload data transmission phase and continues to perform multiple rounds of request collection. When the number of unscheduled devices in the buffer pool reaches or exceeds the number of sub-channels K, the reader suspends sending response opportunity trigger commands, determines that the full-load scheduling condition is met, and prepares to send a scheduling confirmation message.

[0044] Furthermore, the reader sends out a scheduling confirmation message carrying K random device identifiers, implicitly mapping each device to one of the K data sub-channels according to the order of the identifiers. The K scheduled devices concurrently transmit payload data on their respective assigned sub-channels, and the sub-channel utilization rate reaches 100% during the data transmission phase.

[0045] Furthermore, the successfully scheduled passive device immediately shuts down its RF transmission module and enters a sleep state after the payload data transmission is completed. Simultaneously, it actively cancels all copies of request messages it planned to send in subsequent response opportunities within the current frame. The reader synchronously erases all resource block nodes corresponding to the scheduled device in its interference cancellation bipartite graph cache and updates the mapping relationships in the cache.

[0046] In the above process, the embodiments of the present invention ensure that all K sub-channels are 100% filled in each long-duration payload data transmission phase by counting and monitoring the demodulation buffer pool and determining the full load threshold, thus completely eliminating the idle waste of frequency domain sub-channels in the prior art; at the same time, the channel congestion of subsequent time slots is purified from the physical level through the replica circuit breaking mechanism, providing channel quality assurance for continuous and efficient access.

[0047] Step 140: The received signal power of each sub-channel is continuously monitored by the physical layer energy detector. When all sub-channels are below the idle determination threshold within multiple consecutive response opportunities, the subsequent response opportunity triggering process of the current frame is forcibly truncated and terminated by the MAC layer interrupt command.

[0048] In one possible implementation, during the duration of each response opportunity, the received signal power of each sub-channel is continuously detected by a physical layer energy detector. The received energy of each sub-channel is compared with a preset idle determination noise floor threshold to determine whether each sub-channel carries a valid backscatter signal. When the received energy of all sub-channels within a response opportunity is lower than the idle determination threshold, the response opportunity is recorded as a physical idle. When a set number of physical idles occur consecutively, it is determined that all passive devices within the current coverage area have completed scheduling and entered a sleep state.

[0049] In one possible implementation, the subsequent response opportunity triggering process of the current frame is forcibly truncated and terminated by the MAC layer interrupt instruction, and no more time slot triggering instructions are issued. After the current frame is truncated and terminated, if there are still successfully demodulated passive devices in the demodulation buffer pool, the corresponding scheduling confirmation message is issued to complete the payload data transmission of all passive devices.

[0050] Specifically, during each response opportunity duration, the reader continuously detects the received signal power of each sub-channel using a physical layer energy detector, compares the received energy of each sub-channel with a preset idle noise floor threshold, and determines whether it carries a valid backscatter signal. This process can be completed without waiting for baseband decoding.

[0051] Furthermore, when the received energy of all K sub-channels within a response opportunity is lower than the idle determination threshold, the reader records that response opportunity as a physical idle. When a set number of physical idles occur consecutively (default 2 times), the reader determines that all activated passive devices within its coverage area have completed scheduling and entered a sleep state.

[0052] Furthermore, the reader forcibly truncates and terminates the subsequent response opportunity triggering process of the current frame through a MAC layer interrupt instruction, ceasing to issue any remaining time slot triggering instructions and directly ending the current frame. After the current frame is truncated and terminated, if there are still passive devices in the demodulation buffer pool that have been successfully demodulated but are fewer than K in number, the reader issues a scheduling confirmation message containing all remaining devices at once, completing the payload data transmission of the remaining devices.

[0053] In the above process, the embodiments of the present invention use the early stop mechanism of physical layer energy detection and continuous idle determination to enable the system to keenly capture the channel idle characteristics and truncate invalid frame tails in an instant when the device scale is unknown. It can automatically avoid traversing the remaining useless response opportunities without prior knowledge, and greatly eliminate the invalid waiting time under the traditional fixed frame length mechanism.

[0054] Through the above process, this embodiment of the invention uses an irregular degree distribution multinomial to probabilistically sample the number of request message replicas, and implicitly maps the pseudo-random number seed to achieve low-overhead allocation of multi-replica resources. Through multi-round request collection and online continuous interference cancellation mechanisms, it uses resource blocks with a degree of 1 as the starting seed to peel away collision signals layer by layer, recovering the masked device information and overcoming the collision deadlock of traditional time-slotted ALOHA. Through counting and scheduling of the demodulation buffer pool, it ensures full load on multiple channels in each load transmission stage, maximizing frequency domain resource utilization. Through a replica circuit breaker mechanism, it purifies subsequent channel congestion at the physical level. Through physical layer energy detection, it achieves adaptive frame length truncation. These four elements work together to achieve efficient collision recovery, full load scheduling, and rapid termination with extremely low physical layer overhead in scenarios with sudden high-density access of unknown device scale. This effectively solves the problems of idle multi-channel resources, lack of collision recovery, high signaling overhead, and long invalid waiting times in existing technologies, significantly improving the efficiency of large-scale random access in passive IoT.

[0055] In one exemplary embodiment, a passive Internet of Things (IoT) access system is constructed using the passive IoT access method of the present invention. Figure 2A schematic diagram of the model structure of a passive Internet of Things (IoT) access system is shown.

[0056] like Figure 2 As shown, the system consists of a reader / base station (BS) and N active passive IoT tags within the coverage area that need to access the network. The system employs uplink frequency division multiple access (FDMA) technology, providing K uplink sub-channels within a single response opportunity. A frame is divided into L response opportunities, and the reader controls the progression of these opportunities through multiple rounds of trigger commands.

[0057] This system enables passive IoT access. Within each response opportunity, the active device sends a request message (Msg1), the reader performs online continuous interference cancellation and dynamically issues a scheduling confirmation message (Msg2) based on the buffer pool status, and the scheduled device then transmits payload data (Msg3). Unlike the single-packet transmission of traditional slotted ALOHA, this invention allows devices to send d copies of Msg1 within L opportunities.

[0058] To balance the need for continuous interference cancellation with the short packet communication characteristics of passive devices, in this embodiment, the physical layer payload of Msg1 sent by the passive device is set to include two parts: a 16-bit random identifier and a 2-bit degree indicator (indicating the number of copies sent by the device), totaling 18 bits.

[0059] System performance evaluation primarily uses access efficiency (RA Efficiency): ; in, This indicates the total number of devices that successfully completed Msg3 transmission during the access process. This represents the total physical time consumed by the random access procedure, which includes the time of all trigger commands within the frame, the time of receiving Msg1, the idle waiting time without response, and the scheduled transmission time of Msg2 / Msg3.

[0060] At the start of the inventory cycle, the reader uses the current estimate of the equipment size. Calculate the total number of response opportunities for this frame. ( Let be the system throughput proportionality constant, for Based on empirical rules, it is generally taken as 1.09), and the broadcast includes... and the number of sub-channels The paging message. The total number of globally available time-frequency resource blocks (RBs) in the system is... .

[0061] The awakened Upon receiving a paging message, each active device does not request resources centrally, but instead autonomously performs the following resource mapping operations using its built-in random number generator: Degree selection: The device selects degrees based on a preset irregularity distribution polynomial. The number of Msg1 copies that need to be sent in this frame is determined by probability sampling. For example, when At that time, the device has a 50% probability of choosing to send 2 copies, a 28% probability of choosing to send 3 copies, and a 22% probability of choosing to send 8 copies.

[0062] Pseudo-random number seed generation: The device uses its own hardware random number generator, thermal noise, or internal counter to generate an RN16 sequence. This RN16 not only serves as the device's temporary dynamic identifier (RID) within the current frame, but is also directly reused as the pseudo-random number seed for generating the resource mapping pattern. .Right now .

[0063] One-dimensional global resource block computation: the device generates The initialization vector (IV) is input into a pseudo-random sequence generator (PRNG) pre-agreed upon by the reader / base station and the device. From 1 to... Generate in the global resource pool A set of unique pseudo-random integers, used as absolute indices for the resource blocks in the replica: ; in, Indicates the first One copy, This is the one-dimensional absolute position index of the replica in the global resource pool. If duplicate values ​​appear in the generated sequence, the next random number is extracted using a linear congruential or shift register until a result is obtained. Each independent and unique location index constitutes the resource mapping set of this device. .

[0064] Two-dimensional time-frequency resource calculation: After obtaining the one-dimensional resource block index, the device further maps it to two-dimensional time-frequency coordinates transmitted at the physical layer, that is, determines the specific time slot index. and frequency index For any replica index Its mapping formula is as follows: Time slot index : ; Frequency Index : Among them, when hour, .

[0065] By following the steps described above, the device can operate in the corresponding time slot. Upon arrival, in the sub-channel Sending information including its degree and logo The Msg1 replica. A significant advantage of the embodiments of this application is that using a traditional explicit position pointer to indicate the multiple replica status would consume a large amount of additional signaling overhead, which would severely overdraw the limited energy of passive tags. However, under the mechanism of this invention, the payload of the physical layer request message (Msg1) only needs to carry a very short degree. And the RN16 sequence used as a pseudo-random seed. Once the reader or base station successfully demodulates the device's RN16 in any collision-free resource block, it can use the same pseudo-random number generator (PRNG) algorithm as the terminal to synchronously deduce the precise time-frequency location of all replicas of the device locally. This mechanism not only completely avoids the rapid expansion of physical layer signaling but also perfectly supports subsequent online continuous interference cancellation operations with a minimal implicit load.

[0066] Furthermore, in traditional multi-channel random access, if a severe collision occurs during a single request phase, resulting in fewer devices successfully demodulating than the number of uplink sub-channels,... However, the system will still be forced to initiate a long-duration payload data transmission phase (Msg3), resulting in a significant waste of idle frequency domain sub-channels. To completely solve this problem and maximize channel utilization during the data transmission phase, this invention innovatively introduces a multi-round request collection and dynamic full-load scheduling mechanism at the reader / base station end. Within each response opportunity, the system executes the following process: Signal reception and collision-free tag extraction: reader / base station simultaneously The system receives concurrent Msg1 mixed signals on each uplink sub-channel. First, the physical layer quickly scans and locks onto the non-collision sub-channels, successfully demodulating the corresponding passive device identifier and pseudo-random number seed. Then, using the demodulated seed, an online continuous interference cancellation mechanism is synchronously triggered. By backtracking in the buffer and subtracting known interference, the masked RID is further decrypted from the collapsing sub-channels. All valid RIDs newly acquired in the current response opportunity or recovered through SIC are uniformly stored in the demodulation buffer in the reader / base station memory.

[0067] Dynamic full load status determination and backoff triggering: The Media Access Control (MAC) layer of the reader / base station monitors in real time the total number of valid devices that have been collected but not yet scheduled in the demodulation buffer. .

[0068] like This indicates that the currently collected data is insufficient to fill the subsequent long-duration data transmission channel. To avoid spectrum waste, the reader / base station refuses to initiate Msg3 transmission and immediately sends a very short "Backoff Trigger" command on the downlink. Upon receiving this command, active devices within the coverage area decrement their internal backoff counter. Devices with counters reaching zero will send a request in the next Msg1 response opportunity. This process will repeat until the full load condition is met.

[0069] Instantaneous full-load scheduling and concurrent load transmission: If Once the number of devices in the demodulation buffer reaches or exceeds the number of uplink sub-channels... The system triggers full-load scheduling logic. The reader / base station immediately and forcibly interrupts the continued collection of Msg1, and instead sends a scheduling confirmation message (Msg2) carrying precise scheduling information. Msg2 is encapsulated only in a specific order. The RID of each device, the order of which implicitly will... Each device is mapped to a physical layer. On each data sub-channel. Successfully tagged by Msg2. Each device immediately transmits the long-duration payload data (Msg3) concurrently on its respective mapped sub-channel. At this point, the channel utilization during the data transmission phase reaches 100%. If the buffer pool contains... In this embodiment, any excess RIDs will be discarded directly. Devices not scheduled by Msg2 will be considered as having failed to access the device and will proceed to the next frame to compete again.

[0070] Time slot ends and new time slot begins: Once this Once the Msg3 payload data from each device has been transmitted concurrently, the current time slot officially ends. The reader / base station then sends a slot trigger command to initiate the first Msg1 response opportunity in the new time slot, guiding the remaining devices in the passive network to continue accessing the network.

[0071] Through the asynchronous dynamic closed-loop control of "collection-determination-transmission" described above, this mechanism completely decouples the strong binding relationship between control signaling and data transmission, ensuring that any long-duration Msg3 stage is in an absolutely full-load state, greatly improving the system's ultimate throughput.

[0072] Furthermore, in scenarios with massive tag access, the classic slotted ALOHA, limited by the hard-decision logic of single-packet parsing, completely lacks collision recovery capabilities, making it highly susceptible to system paralysis and a precipitous drop in system throughput due to severe signal aliasing. To completely resolve multi-packet collisions under heavy load, the reader / base station in this invention not only performs Online Continuous Interference Cancellation (Online SIC) at the physical layer using a minimal implicit load, but also introduces an original replica circuit breaker mechanism at the MAC layer. The two work asynchronously and collaboratively in the time domain to achieve dynamic channel purification.

[0073] Online continuous interference cancellation completely overcomes the limitation of classic mechanisms lacking collision recovery capabilities. Furthermore, unlike conventional anti-collision schemes that typically wait for the entire frame of data to be received before offline decoding begins, the reader / base station of this invention can perform SIC operations in real-time and online during time slot progression. The specific process is as follows: At the end of each response opportunity, the reader / base station scans all historical receive buffers to find collision-free resource blocks occupied by only one device. The baseband processor demodulates this resource block, extracting the device's identifier (RID) and pseudo-random number seed (Seed). Next, using the extracted Seed and the same pseudo-random number generation algorithm as the device, the reader / base station accurately derives the device's one-dimensional resource block index set for the entire frame locally. Next, based on the deduced historical collision locations, the reader / base station uses the demodulated signal combined with the channel estimate of the corresponding resource block to reconstruct the physical layer waveform component of the device in the collision block in the baseband, and then precisely subtracts it from the mixed signal in the receive buffer. Finally, after interference cancellation, the resource block where the collision occurred may expose a new covert device signal with a degree of 1. The reader / base station will repeatedly iterate the above "extraction-deduction-cancellation" process until no new effective decoding can be generated.

[0074] The future replication circuit breaker mechanism is the core logic of this invention for breaking high-load decoding deadlock. When a device is in the... After successfully demodulating the response opportunity and subsequently completing the Msg3 data transmission via Msg2, the tag will actively enter sleep mode. Specifically, once the device receives a Msg2 scheduling confirmation for itself, it immediately shuts down the RF transmission module and enters an extremely low-power sleep state, actively canceling all planned Msg1 copies to be transmitted later. This operation directly removes the interference source for subsequent time slots at the physical level.

[0075] Furthermore, when dealing with extreme bursts of traffic or unknown device scale, the traditional fixed frame length mechanism has a fatal flaw: if there are few devices but the preset frame length is extremely large, it will generate a massive number of blank time slots, resulting in a serious waste of inventory time. To solve this problem, this invention proposes a closed-loop control algorithm based on Basic Estimation and Fast Termination (BE-FT) to achieve adaptive, rapid truncation and accurate prediction of frame length. Physical Idle Detection and Early Frame Termination (EFT): During each Msg1 response opportunity collected in multiple rounds of requests, the reader / base station continuously performs physical idle detection and early termination. Each uplink subchannel performs physical layer energy sensing without waiting for complex baseband decoding. If, within the duration of a response opportunity, all If the received energy on each sub-channel is below a preset noise floor threshold, it is determined that no valid backscatter signal has been received, and this response opportunity is recorded as a physical idle. Due to the randomness of the irregular repetition strategy, a single idle may simply be a probabilistic coincidence. Therefore, the system sets a continuous idle threshold. It is usually set to 2. When the reader / base station continuously detects... When a response opportunity becomes physically idle, the MAC layer determines that all active devices in the network have been successfully scheduled and entered a sleep state. At this time, the reader / base station immediately triggers an early stop interrupt, directly truncating the current frame and no longer issuing subsequent trigger commands, thus avoiding the time overhead of traversing the remaining dozens or even hundreds of useless response opportunities.

[0076] Basic Estimation (BEst) Inter-frame control: After the current frame ends normally or is prematurely truncated by the above EFT mechanism, since there may be devices in the network that cannot be accessed normally due to excessive collisions, the reader / base station needs to re-estimate the scale of devices that have not yet been accessed in the environment based on the number of collisions in this frame, so as to guide the parameter configuration of the next frame.

[0077] Specifically, the reader / base station counts the total number of sub-channels that actually experienced Msg1 collisions in this frame and failed to be decrypted by online SIC. Next, using the total number of collisions, the number of devices is estimated through a basic multiplier model: ; Where, constant The expected average number of unconnected devices contained in each collision block. Derived from the classical ALOHA collision probability theory, in this embodiment... The preferred value is 2.39.

[0078] Finally, the reader / base station calculates the number of devices. Combined with the number of sub-channels and optimal system load factor Recalculate the total number of next-frame response opportunities that maximize system throughput: Subsequently, the reader / base station immediately broadcasts information carrying the new... The paging message for the parameters initiates the next frame's data storage. Through this closed-loop iteration of "truncation-estimation-reconfiguration," the system can rapidly approach its optimal operating state without any prior knowledge.

[0079] In an application scenario, such as Figure 3 and Figure 4 As shown, to verify the effectiveness of the multi-round request collection and dynamic full-load scheduling mechanism, low-overhead online continuous interference cancellation and replica circuit breaking algorithm, and physical idle state-aware early termination mechanism (BE-FT) proposed in the embodiments of this invention in the passive IoT large-scale access scenario, numerical simulations were performed, and the performance was compared with B-RAP and E-RAP in the 3GPP standard. Among them, B-RAP represents the traditional basic single-packet slot ALOHA access mechanism, and E-RAP represents the extended access mechanism with dual Msg1 opportunities.

[0080] In the simulation, based on typical RFID application scenarios, the following bit durations were set: paging message duration; time slot trigger and backoff trigger duration; Msg1 duration; Msg3 duration (significantly longer than Msg2 duration), where Msg2 represents the number of successful Msg1 responses within a time slot; bit duration between no responses; and the number of uplink FDMA subchannels. Access efficiency was used as the core performance criterion. For fair comparison, all simulation schemes were configured under the same physical environment and protocol constraints. The resources of this invention and existing technologies are defined to ensure full data storage during unknown bursts of massive tag traffic. Specifically, for different schemes, the logical frame timing structure corresponding to their resources differs, but the physical constraints allowing uplink tag transmission are absolutely consistent.

[0081] Figure 3 Showing different active tag sizes ( The simulation results show the performance of the system access efficiency as a function of the allocated frame length. It can be seen that, under a fixed tag size, the access efficiency of each scheme first rises to a peak and then slowly decreases with the change of frame length. This reflects the balance between high-frequency collisions caused by excessively small frame lengths and channel idleness caused by excessively large frame lengths. Further comparison of the performance of different schemes in the extremely small frame length range shows that the access efficiency of the embodiment of this invention is inferior to the traditional B-RAP and E-RAP schemes at smaller frame lengths. This is because the multi-replica mechanism generates excessive concurrent conflicts under extremely compact frame lengths, leading to deadlock in Online SIC decoding. However, as the frame length increases, the peak efficiency of each set of curves increases significantly, with the peak value of the embodiment of this invention being significantly higher than that of existing technologies. Furthermore, the coordinate distribution of the optimal frame length for achieving the highest access efficiency for each set of curves basically conforms to the optimal theoretical calculation formula given in this paper. Therefore, although this invention suffers from a temporary performance disadvantage due to replica overhead under extreme heavy loads, as long as a reasonable frame length is allocated, the frequency domain resource utilization can be significantly improved through multiple rounds of collection and full-load scheduling.

[0082] Figure 4 The paper demonstrates a comparison of the performance limits of the present invention's solution with existing technologies under the same sub-channel constraints and unified reception conditions in a massive tag access scenario. Figure 4 The horizontal axis represents the total number of actual tags, and the vertical axis represents the highest access efficiency achievable by the system. It can be seen that the efficiency ceiling of the traditional B-RAP single-packet parsing logic consistently hovers around 0.012; the E-RAP scheme, due to providing additional access opportunities, achieves a maximum efficiency of approximately 0.016. In contrast, the efficiency ceiling curve of this invention, when the total number of actual tags increases sharply, presents a perfect horizontal straight line, stabilizing at around 0.022. Under the same conditions, the access efficiency of this invention reaches 183.3% and 137.5% of the two comparative schemes mentioned above, respectively, and the system's large-scale concurrent throughput performance is significantly higher than that of the two comparative schemes.

[0083] The above results indicate that the performance gains of this invention mainly stem from three aspects: First, the traditional single-round request interaction is optimized into multi-round dynamic collection, triggering long-duration data transmission only when the number of successfully demodulated devices meets the multiple access sub-channel K, completely eliminating the idle waste of long time slots in the frequency domain; second, through online continuous interference cancellation combined with a future replica circuit breaker mechanism, efficient separation and layer-by-layer stripping of collision signals are achieved, significantly improving the concurrent decoding capability under high load; finally, combined with the BE-FT mechanism, the system can automatically truncate invalid long-tail time slots under unknown device scale, always locking in the optimal performance range without prior knowledge. Therefore, this invention completely breaks through the capacity bottleneck of the traditional ALOHA mechanism with low physical layer overhead, and is suitable for high-density passive tag storage and large-scale access scenarios of cellular IoT with extreme burst characteristics.

[0084] In another application scenario, the multi-channel passive IoT large-scale random access method based on low-overhead multi-round requests provided by this invention is implemented and executed interactively by a reader and several passive devices, including the following steps: Step 1, Frame Initialization and Multiple Access Resource Mapping: The reader calculates the total number of response opportunities L and the number of sub-channels K of the initial frame based on the currently estimated total number of devices, and broadcasts a paging message containing the above parameters; each activated passive device determines the number d of request message copies it needs to send according to a preset irregularity distribution polynomial, generates a pseudo-random number seed, and uses the pseudo-random number seed to pseudo-randomly select d transmission time slots and corresponding sub-channels from the L response opportunities.

[0085] Step 2, Multi-round Request Collection and Online Continuous Interference Cancellation: The reader sends trigger commands one by one to open response opportunities; the passive device sends a request message carrying its own random identifier and pseudo-random number seed in the selected transmission time slot; the reader receives the signal and performs online continuous interference cancellation, searches for a collision-free resource block with a degree of 1 to demodulate the passive device information, uses the demodulated pseudo-random number seed to reconstruct the replica position of the device in other time slots, eliminates the corresponding interference from the received signal buffer, and stores the successfully demodulated passive device in the demodulation buffer pool.

[0086] Step 3, Dynamic Full-Load Scheduling and Future Replica Circuit Breaker: The reader monitors the demodulation buffer pool in real time. When the number of unscheduled passive devices in the buffer pool reaches or exceeds the number of sub-channels K, the reader pauses sending trigger commands and sends a scheduling confirmation message containing K devices. The passive devices that receive the scheduling confirmation message perform payload data transmission on the allocated sub-channels. After the transmission is completed, they enter a sleep state and actively cancel all request message replicas that they plan to send in subsequent response opportunities. The reader simultaneously erases the future nodes corresponding to the scheduled devices in its interference cancellation bipartite graph buffer.

[0087] Step 4, Early Termination Based on Physical Idle State: The reader continuously monitors the physical energy state of the channel during each response opportunity; when no transmission signal from any passive device is detected during multiple consecutive response opportunities, the reader determines that all activated devices within the current coverage area have completed scheduling and entered sleep mode, triggering the early termination mechanism and directly truncating the current frame.

[0088] Furthermore, in step 1, the physical layer payload of the request message (Msg1) sent by the passive device includes: a 16-bit random identifier (RID) and a degree indicator field representing the total number of replicas sent by the current device, wherein the RID serves as a pseudo-random number seed (PRNG Seed) for finding replicas; the reader does not need to carry an explicit position pointer in the request message, but can reconstruct the complete replica sending sequence of the device locally using only the pseudo-random number seed and the degree indicator.

[0089] Furthermore, in step 3, if the current frame is terminated prematurely or reaches the maximum frame length normally, and there are still passive devices in the demodulation buffer pool that have been successfully demodulated but are not numerous enough, the reader will send a scheduling confirmation message containing all the remaining devices at once to complete the payload data transmission of the remaining devices.

[0090] Furthermore, in step 4, the specific judgment condition for the reader to trigger the early termination mechanism is: within a consecutive number of response opportunities, no radio frequency signal energy of the request message is detected on all sub-channels, where the idle judgment threshold is used.

[0091] It should be noted that the basic modules involved in this invention, such as Continuous Interference Cancellation (SIC), FDMA subchannel partitioning, and standard slotted ALOHA timing structure, can all be implemented using existing mature technologies in the field. Their underlying principles are not considered as independent protected objects of this invention. The substantive innovation and protection focus of this invention lies in the multi-dimensional collaboration and cross-layer reconstruction of the aforementioned technologies, specifically encompassing the following core combinations: an implicit request replica generation strategy based on pseudo-random number seeds, an online multi-round request collection and dynamic full-load scheduling strategy, a future replica circuit breaker mechanism based on online continuous interference cancellation, and an early termination mechanism based on physical idle state awareness. Through this combination, this invention completely overcomes the inherent defects of classic slotted ALOHA—lack of collision recovery capability and severe idleness of multi-channel resources due to single-round requests—and completely eliminates the redundant physical idle waiting time under the traditional fixed frame length mechanism. Therefore, in bursty access scenarios with unknown device scale, it maximizes the utilization rate of multi-channel resources and significantly improves the large-scale random access efficiency of passive IoT systems.

[0092] In summary, the multi-channel passive IoT large-scale random access method based on low-overhead multi-round requests proposed in this invention has the characteristics of low physical layer overhead, strong resistance to sudden high loads, and extremely high adaptability to unknown device scale. Therefore, it can be widely applied to various scenarios that require the deployment of massive passive tags or micro / zero-power terminals. Specifically, this invention can be applied to at least the following fields, but is not limited thereto: Logistics warehousing and retail inventory management scenarios: In large warehouses, logistics centers, and supermarkets, there are often situations where hundreds or even thousands of goods and pallets with passive tags suddenly flood into the reading range, resulting in extreme uncertainty and unpredictability in the number of devices. This invention, through dynamic full-load scheduling and early termination mechanisms, can rapidly complete high-density tag reading and instantly release the channel without relying on device count estimation, significantly shortening inventory time. It is suitable for rapid inbound and outbound management of pallet-level, box-level, and single-item-level goods.

[0093] Supply Chain Tracking and Anti-counterfeiting: For products such as pharmaceuticals, tobacco and alcohol, luxury goods, and auto parts, the scale of their circulation changes dynamically in the production, warehousing, transportation, and terminal sales stages. The adaptive frame length truncation and multi-channel efficient utilization features of this invention can provide highly timely data acquisition capabilities for batch reading of passive tags at each stage, ensuring real-time anti-counterfeiting and flow management.

[0094] Industrial Internet and Smart Manufacturing Scenarios: In smart factories, flexible production lines, AGV / robot collaborative workshops, and other scenarios involve high-density aggregation of tooling, fixtures, materials, and workpieces. The online interference cancellation and copy-breaking mechanism proposed in this invention can effectively address sudden, dense channel collisions within the workshop, enabling rapid, deadlock-free concurrent identification of massive production elements, and empowering transparent production and precise tracking of work-in-process.

[0095] Smart City and Infrastructure Management: In scenarios such as shared bicycle management, smart parking, municipal pipeline signage, and street light and manhole cover monitoring, it is often necessary to periodically scan facilities in specific areas using inspection vehicles or drones. This invention, through efficient irregular repetitive separation and early stopping mechanisms during intermittent, mobile scanning, maximizes channel capacity within a very short dwell time, enabling extremely rapid acquisition of the status of massive amounts of urban assets.

[0096] Smart Agriculture and Environmental Monitoring: In wide-area scenarios such as farmland, forest areas, and water conservancy projects, environmental sensing nodes or passive tags for crops are widely distributed and vary in density. This invention enables base stations or inspection readers to quickly complete inventory checks and trigger early shutdowns in sparsely populated areas to save time, while leveraging the advantages of multi-round requests in densely populated areas to completely resolve conflicts, achieving low-cost, high-efficiency, long-term monitoring over a wide area.

[0097] Medical and Health Asset Management: In hospitals, nursing homes, laboratories, and other locations, there are various types of medical devices, pharmaceuticals, consumables, wheelchairs, and monitoring equipment. The low physical layer overhead and adaptive scheduling characteristics of this invention allow it to work with access control readers or corridor base stations to quietly and rapidly complete background automatic inventory and abnormal asset alarms without consuming excessive wireless spectrum resources or interfering with conventional medical wireless devices (such as Wi-Fi and Bluetooth).

[0098] Applications in conjunction with next-generation cellular communication systems: The access mechanism of this invention is highly aligned with 3GPP's standardization evolution direction for passive IoT in 5G-Advanced and future 6G networks. It can be directly embedded into the MAC layer protocol stack of cellular base stations, working in conjunction with technologies such as uplink frequency division multiple access (FDMA), network slicing, and edge computing. As a unified access foundation for macrocellular networks facing massive numbers of passive terminals per square kilometer (tens of millions), it supports the intelligent interconnection of everything in future scenarios.

[0099] Through the above process, this invention is not only directly applicable to the rapid inventory of sudden massive numbers of tags in existing multi-channel RFID systems and cellular passive IoT systems, but it can also be flexibly combined with various sensing and communication technologies of future 6G networks, effectively breaking through the physical bottlenecks of traditional random access mechanisms in terms of capacity and efficiency. It has extremely broad engineering application value and good industrialization prospects.

[0100] The following are embodiments of the apparatus of the present invention, which can be used to execute the passive IoT access method involved in the present invention. For details not disclosed in the embodiments of the apparatus of the present invention, please refer to the method embodiments of the passive IoT access method involved in the present invention.

[0101] Please see Figure 5 This invention provides a passive Internet of Things access device 800.

[0102] The passive IoT access device 800 includes, but is not limited to: a frame initialization and resource mapping module 810, a multi-round collection and interference cancellation module 830, a full-load scheduling and replica circuit breaker module 850, and a physical idle and early termination module 870.

[0103] The frame initialization and resource mapping module 810 is used to perform probability sampling on the number of copies of the request message of the passive device through an irregular degree distribution multinomial, and to perform mapping calculation on the pseudo-random number seed and the global resource block index through a pseudo-random number generator, so as to allocate multiple request messages of each passive device to the corresponding response time slot and sub-channel.

[0104] The multi-round collection and interference cancellation module 830 is used to receive and buffer request messages by triggering response opportunities one by one, demodulate the resource blocks with a buffer signal of 1 to extract random identifiers and seeds, obtain the replica position by inverse mapping the seed through a pseudo-random number generator, and peel off the mixed signal of the colliding resource blocks layer by layer according to the replica position.

[0105] The full-load scheduling and replica circuit breaker module 850 is used to count the demodulated but unscheduled passive devices through the demodulation buffer pool. When the number of sub-channels is reached, the module allocates sub-channels and authorizes the payload transmission of a specified number of passive devices, cancels the pending request message replicas of the passive devices, and simultaneously erases the resource block nodes corresponding to the scheduled passive devices.

[0106] The Physical Idle and Early Termination Module 870 is used to continuously monitor the received signal power of each sub-channel through the physical layer energy detector. When all sub-channels are below the idle determination threshold within multiple consecutive response opportunities, the subsequent response opportunity triggering process of the current frame is forcibly truncated and terminated through the MAC layer interrupt instruction.

[0107] It should be noted that the passive IoT access provided in the above embodiments is only an example of the division of the above functional modules. In actual applications, the above functions can be assigned to different functional modules as needed. That is, the internal structure of the passive IoT access device will be divided into different functional modules to complete all or part of the functions described above.

[0108] Furthermore, the passive IoT access device and the passive IoT access method provided in the above embodiments belong to the same concept, and the specific way in which each module performs its operation has been described in detail in the method embodiments, and will not be repeated here.

[0109] Figure 6 A schematic diagram of the structure of an electronic device according to an exemplary embodiment is shown.

[0110] It should be noted that this electronic device is merely an example adapted to the present invention and should not be construed as providing any limitation on the scope of use of the present invention. Furthermore, this electronic device should not be interpreted as requiring or depending on having... Figure 6 One or more components of the exemplary electronic device 2000 shown.

[0111] The hardware structure of electronic devices 2000 can vary significantly due to differences in configuration or performance, such as... Figure 6 As shown, the electronic device 2000 includes: a power supply 210, an interface 230, at least one memory 250, and at least one central processing unit (CPU) 270.

[0112] Specifically, power supply 210 is used to provide operating voltage for various hardware devices on electronic device 2000.

[0113] Interface 230 includes at least one wired or wireless network interface 231 for interacting with external devices. Of course, in other examples adapted to this invention, interface 230 may further include at least one serial-to-parallel conversion interface 233, at least one input / output interface 235, and at least one USB interface 237, etc. Figure 6 As shown, this does not constitute a specific limitation.

[0114] The memory 250 serves as a carrier for resource storage and can be a read-only memory, random access memory, disk, or optical disk, etc. The resources stored on it include the operating system 251, application programs 253, and data 255, etc., and the storage method can be temporary storage or permanent storage.

[0115] The operating system 251 is used to manage and control the various hardware devices and application programs 253 on the electronic device 2000, so as to enable the central processing unit 270 to perform calculations and processing on the massive data 255 in the memory 250. It can be Windows Server™, Mac OS X™, Unix™, Linux™, FreeBSD™, etc.

[0116] Application 253 is a computer-readable instruction based on operating system 251 that performs at least one specific task, and may include at least one module ( Figure 6 (Not shown), each module may contain computer-readable instructions for electronic device 2000. For example, a passive Internet of Things access device may be considered as application 253 deployed on electronic device 2000.

[0117] Data 255 may be signal information, etc., and is stored in memory 250.

[0118] The central processing unit 270 may include one or more processors and is configured to communicate with the memory 250 via at least one communication bus to read computer-readable instructions stored in the memory 250, thereby enabling the computation and processing of massive amounts of data 255 in the memory 250. For example, a passive Internet of Things access method can be implemented by having the central processing unit 270 read a series of computer-readable instructions stored in the memory 250.

[0119] Furthermore, the present invention can also be implemented through hardware circuits or a combination of hardware circuits and software. Therefore, the implementation of the present invention is not limited to any specific hardware circuit, software, or combination thereof.

[0120] Please see Figure 7 This invention provides an electronic device 4000, which may include: a desktop computer, a laptop computer, a server, etc., with sensor recognition capabilities.

[0121] exist Figure 7 In this context, the electronic device 4000 includes at least one processor 4001 and at least one memory 4003.

[0122] The data interaction between the processor 4001 and the memory 4003 can be achieved through at least one communication bus 4002. This communication bus 4002 may include a path for transmitting data between the processor 4001 and the memory 4003. The communication bus 4002 may be a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus, etc. The communication bus 4002 can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 7 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0123] Optionally, the electronic device 4000 may further include a transceiver 4004, which can be used for data interaction between the electronic device and other electronic devices, such as sending and / or receiving data. It should be noted that in practical applications, the transceiver 4004 is not limited to one type, and the structure of the electronic device 4000 does not constitute a limitation on the embodiments of the present invention.

[0124] Processor 4001 may be a CPU (Central Processing Unit), a general-purpose processor, a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It can implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this invention. Processor 4001 may also be a combination that implements computing functions, such as including one or more microprocessor combinations, a combination of a DSP and a microprocessor, etc.

[0125] The memory 4003 may be a ROM (Read Only Memory) or other type of static storage device capable of storing static information and instructions, RAM (Random Access Memory) or other type of dynamic storage device capable of storing information and instructions, or an EEPROM (Electrically Erasable Programmable Read Only Memory), CD-ROM (Compact Disc Read Only Memory) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium capable of carrying or storing desired program instructions or code in the form of instructions or data structures and accessible by the electronic device 4000, but not limited thereto.

[0126] The memory 4003 stores computer-readable instructions, and the processor 4001 can read the computer-readable instructions stored in the memory 4003 through the communication bus 4002.

[0127] The computer-readable instructions are executed by one or more processors 4001 to implement the passive Internet of Things access methods in the above embodiments.

[0128] Furthermore, this embodiment of the invention provides a storage medium storing computer-readable instructions, which are executed by one or more processors to implement the passive IoT access method described above.

[0129] This invention provides a computer program product, which includes computer-readable instructions stored in a storage medium. One or more processors of an electronic device read the computer-readable instructions from the storage medium, load and execute the computer-readable instructions, thereby enabling the electronic device to implement the passive Internet of Things access method as described above.

[0130] Compared with related technologies, the beneficial effects of the present invention are: 1. This invention enables efficient recovery of collision signals, significantly improving the system throughput limit in high-density burst access scenarios. By carrying only a 16-bit random identifier as a pseudo-random number seed in the request messages sent by each passive device, after successfully demodulating any collision-free resource block, the reader can use this seed and a pseudo-random sequence generator identical to the device's on-site to locally inverse map and deduce the complete time-frequency positions of all replicas of that device. Based on this, the mixed signals of collision resource blocks in the historical cache are reconstructed and gradually reduced and stripped away, iterating repeatedly until no new effective decoding can be generated. On this basis, the successfully scheduled device actively cancels all subsequent pending replicas, and the reader synchronously erases the corresponding resource block nodes in the bipartite graph cache, continuously purifying channel congestion from a physical level. The above mechanism allows hidden devices that were originally unable to be demodulated due to signal aliasing to be exposed and recovered layer by layer, completely breaking through the system deadlock and precipitous drop in throughput that are easily caused by the lack of collision recovery capability in traditional time-slot ALOHA under heavy load.

[0131] 2. This invention maximizes the utilization of multi-channel time-frequency resources and eliminates the waste of idle frequency domain sub-channels. By setting up a demodulation buffer pool, the random identifiers of devices that have been successfully demodulated but not yet scheduled in each response opportunity are temporarily accumulated. The reader monitors the buffer pool count in real time, and only when the number of demodulated but unscheduled devices reaches or exceeds the number of sub-channels K is the extremely long payload data transmission phase triggered. The random identifiers in the dispatch confirmation message implicitly map each device to one of the K physical layer sub-channels, ensuring that the K scheduled devices concurrently transmit payload data on their respective assigned sub-channels. This mechanism ensures that all sub-channels are 100% fully loaded in each long data transmission phase, completely avoiding the serious waste of frequency domain resources caused by insufficient number of successfully demodulated devices leading to a large number of idle sub-channels in the traditional single-round request collection mechanism.

[0132] 3. This invention can adapt to unknown device scale and effectively eliminate invalid idle waiting time. By continuously detecting the received signal power of each sub-channel during each response opportunity duration using a physical layer energy detector, the received energy is compared with a preset idle determination noise floor threshold. This allows for determination of whether each sub-channel carries a valid backscatter signal without waiting for complex baseband decoding. When all sub-channels are below the idle determination threshold within multiple consecutive response opportunities, the reader determines that all activated devices within its coverage area have completed scheduling and entered a sleep state. A MAC layer interrupt command forcibly truncates and terminates the subsequent response opportunity triggering process for the current frame, preventing the issuance of any remaining time slot triggering commands. This mechanism allows the system to accurately capture channel physical idle characteristics and instantly truncate invalid frame tails without prior knowledge of the device scale, avoiding the massive time overhead caused by blindly traversing idle time slots under a fixed large frame length mechanism. It is particularly suitable for sudden inventory scenarios where the number of devices changes dynamically and cannot be accurately estimated in advance.

[0133] 4. This invention supports complex media access control algorithms with extremely low physical layer overhead and adapts to the physical constraints of low-power, short-packet transmission in passive devices. By simultaneously multiplexing a 16-bit random sequence generated by the device's built-in random number generator as a temporary dynamic identifier and a pseudo-random number seed, and using this seed to synchronously complete the mapping and inverse mapping of multiple replica time-frequency positions on both the sender and receiver, the traditional anti-collision scheme requires carrying an explicit position pointer in the request message. The physical layer payload of the request message sent by the passive device only needs to contain a 16-bit random identifier and a 2-bit degree indicator, totaling 18 bits. While avoiding a significant increase in physical layer transmission time, this invention perfectly supports the complex online continuous interference cancellation algorithm of the media access control layer with a minimal implicit payload, making it highly feasible in engineering under the constraints of limited energy of passive devices and a minimal protocol stack.

[0134] 5. This invention can automatically approach the optimal operating state without prior knowledge through inter-frame closed-loop iterative control. After the current frame ends normally or is prematurely terminated, the reader counts the total number of sub-channels that actually experienced request message collisions in the current frame and failed to be resolved by online continuous interference cancellation. Using the total number of collisions and a constant factor, it estimates the scale of devices that have not yet successfully connected through a basic multiplier model. Combining the number of sub-channels and the optimal system load coefficient, it recalculates the total number of response opportunities for the next frame that maximizes system throughput. It then immediately broadcasts a paging message carrying the updated frame parameters to initiate the next frame's readiness. This "truncation-estimation-reconfiguration" closed-loop iterative mechanism enables the system to rapidly and adaptively adjust the frame length configuration in an environment where the scale of devices is completely unknown and dynamically changing, without relying on any prior knowledge, always locking in the optimal performance operating range.

[0135] It should be understood that although the steps in the flowcharts of the accompanying figures are shown sequentially as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the accompanying figures may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the sub-steps or stages of other steps.

[0136] The above description is only a partial embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A passive Internet of Things (IoT) access method, characterized in that, The method includes: The number of copies of the request message of the passive device is probabilistically sampled by an irregular degree distribution multinomial, and the pseudo-random number seed and global resource block index are mapped and calculated by a pseudo-random number generator. The multiple request messages of each passive device are then allocated to the corresponding response time slots and sub-channels. The request message is received and cached by responding to the opportunity one by one, and the random identifier and seed are extracted by demodulating the resource block with a moderate degree of 1 in the cache signal. The replica position is obtained by inverse mapping the seed through a pseudo-random number generator, and the mixed signal of the colliding resource block is stripped layer by layer according to the replica position. The demodulation buffer pool counts the demodulated but unscheduled passive devices. When the number of sub-channels is reached, a specified number of passive devices are allocated sub-channels and granted payload transmission authorization. The pending request message copies of the passive devices are canceled, and the resource block nodes corresponding to the scheduled passive devices are erased simultaneously. The received signal power of each sub-channel is continuously monitored by the physical layer energy detector. When all sub-channels are below the idle determination threshold within multiple consecutive response opportunities, the subsequent response opportunity triggering process of the current frame is forcibly truncated and terminated by the MAC layer interrupt instruction.

2. The passive IoT access method as described in claim 1, characterized in that, The step of probabilistically sampling the number of replicas of the request message from the passive device using an irregular degree distribution multinomial includes: The number of replicas of the request message to be sent by each passive device in this frame is determined by probability sampling according to the preset irregular degree distribution polynomial, and written as a degree indicator field into the physical layer payload of each request message replica; the irregular degree distribution polynomial defines the probability distribution of the passive device selecting different numbers of replicas.

3. The passive IoT access method as described in claim 2, characterized in that, The step of mapping the pseudo-random number seed to the global resource block index using a pseudo-random number generator, and allocating multiple request messages from each passive device to the corresponding response time slots and sub-channels, includes: A random sequence is generated by the hardware random number generator, thermal noise, or internal counter built into the passive device; the random sequence serves as a temporary dynamic identifier for the passive device within this frame and a pseudo-random number seed for generating resource mapping patterns. The pseudo-random number seed is used as an initialization vector and input into the pseudo-random sequence generator to generate a unique pseudo-random integer corresponding to the number of replicas in a resource pool ranging from 1 to the total number of global resource blocks. This integer serves as the absolute index of the global resource block for each replica of the passive device. If duplicate values ​​appear in the generated pseudo-random integers, the next random number is extracted by a linear congruent or shift register. Two-dimensional time-frequency calculation is performed on the absolute index of each global resource block to determine the corresponding response time slot number and sub-channel number, and the resource mapping set is stored in the local cache.

4. The passive IoT access method as described in claim 3, characterized in that, The step of receiving and caching the request message through successive triggering of response opportunities, and demodulating and extracting random identifiers and seeds from resource blocks with a cached signal degree of 1, includes: The time slot trigger command is sent sequentially. During the duration of each response opportunity, a request message carrying the pseudo-random number seed and the degree indicator field is sent according to the response time slot sequence number and sub-channel number corresponding to the request message of the passive device. In each response opportunity, concurrent request message mixed signals are received on each of the sub-channels. All received signals are stored in the baseband buffer. All baseband buffers are scanned to search for and locate collision-free resource blocks with a resource block degree of 1 and demodulate them to extract pseudo-random number seeds and degree indicators.

5. The passive IoT access method as described in claim 4, characterized in that, The process of obtaining the replica position by inverse mapping the seed using a pseudo-random number generator, and then peeling off the mixed signal of the collision resource block layer by layer based on the replica position, includes: The demodulated pseudo-random number seed is used as the initialization vector input to the pseudo-random sequence generator. In the resource pool from 1 to the total number of global resource blocks, the absolute index of all global one-dimensional resource blocks of the passive device in this frame is generated to obtain the replica position. The replica location is compared with the actual received signal. For resource blocks that collide, the physical layer waveform component of the passive device in the resource block is reconstructed based on the demodulated signal of the passive device and then subtracted from the mixed received signal. This process is repeated until no new valid decoding can be generated.

6. The passive IoT access method as described in claim 1, characterized in that, The process of counting demodulated but unscheduled passive devices through a demodulation buffer pool, and when the sub-channel number is reached, allocating sub-channels and granting payload transmission authorization to a specified number of passive devices, canceling the pending request message copies of the passive devices, and synchronously erasing the resource block nodes corresponding to the scheduled passive devices, includes: All valid passive device random identifiers for each response opportunity are uniformly stored in the demodulation buffer pool in memory, and the number of devices that have been demodulated but have not yet been scheduled is counted in real time, and the number of devices is continuously monitored. When the number of devices reaches or exceeds the total number of sub-channels, the trigger command for sending response opportunities is suspended, and a scheduling confirmation message carrying a random identifier is sent to implicitly map each device to a sub-channel of the physical layer according to the order of the random identifiers. Simultaneously, all copies of request messages that the scheduled passive device plans to send in subsequent response opportunities of the current frame are cancelled, and all resource block nodes corresponding to the scheduled passive device are erased in the interference cancellation bipartite graph cache used to characterize the mapping relationship between resource blocks and devices.

7. The passive IoT access method as described in claim 1, characterized in that, The continuous monitoring of the received signal power of each sub-channel via a physical layer energy detector, and the forced termination of the subsequent response opportunity triggering process of the current frame via a MAC layer interrupt command when all sub-channels are below the idle determination threshold within multiple consecutive response opportunities, includes: During the duration of each response opportunity, the received signal power of each sub-channel is continuously detected by the physical layer energy detector. The received energy of each sub-channel is compared with a preset idle determination noise floor threshold to determine whether each sub-channel carries a valid backscatter signal. When the received energy on all sub-channels within a response opportunity is lower than the idle determination threshold, the response opportunity is recorded as a physical idle. When a set number of physical idles occur consecutively, it is determined that all passive devices within the current coverage area have completed scheduling and entered a sleep state. The subsequent response opportunity triggering process of the current frame is forcibly truncated and terminated by the MAC layer interrupt instruction, and no more time slot triggering instructions are issued. After the current frame is truncated and terminated, if there are still successfully demodulated passive devices in the demodulation buffer pool, the corresponding scheduling confirmation message is issued to complete the payload data transmission of all passive devices.

8. A passive Internet of Things (IoT) access device, characterized in that, The device includes: The frame initialization and resource mapping module is used to perform probability sampling on the number of copies of the request message of the passive device through an irregular degree distribution multinomial, and to perform mapping calculation on the pseudo-random number seed and the global resource block index through a pseudo-random number generator, so as to allocate multiple request messages of each passive device to the corresponding response time slot and sub-channel. The multi-round collection and interference cancellation module is used to receive and cache the request message by triggering the response opportunity one by one, demodulate the resource block with a moderate degree of 1 in the cached signal to extract the random identifier and seed, and obtain the replica position by inverse mapping the seed through a pseudo-random number generator. The mixed signal of the colliding resource block is stripped layer by layer according to the replica position. The full-load scheduling and replica circuit breaker module is used to count the demodulated but unscheduled passive devices through the demodulation buffer pool. When the number of sub-channels is reached, the module allocates sub-channels and grants payload transmission authorization to a specified number of passive devices, cancels the pending request message replicas of the passive devices, and simultaneously erases the resource block nodes corresponding to the scheduled passive devices. The physical idle and early termination module is used to continuously monitor the received signal power of each sub-channel through the physical layer energy detector. When all sub-channels are below the idle determination threshold within multiple consecutive response opportunities, the subsequent response opportunity triggering process of the current frame is forcibly truncated and terminated through the MAC layer interrupt instruction.

9. An electronic device, characterized in that, include: At least one processor and at least one memory, wherein, The memory stores computer-readable instructions; The computer-readable instructions are executed by one or more of the processors, causing the electronic device to implement the passive Internet of Things access method as described in any one of claims 1 to 7.

10. A storage medium having computer-readable instructions stored thereon, characterized in that, The computer-readable instructions are executed by one or more processors to implement the passive Internet of Things access method as described in any one of claims 1 to 7.

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