Wireless TDMA real-time and throughput hybrid scheduling method based on double-layer time slot separation

Abstract

The invention relates to the technical field of time division multiple access resource scheduling in a wireless communication network, in particular to a wireless time division multiple access (TDMA) real-time and throughput hybrid scheduling method based on double-layer time slot separation, which comprises access point equipment data; constructing a layered time reference based on the collected data, and periodically generating a frame synchronization signal and a micro-frame synchronization signal; configuring a transmission structure comprising a fast access time slot region, a deterministic time slot region and a capacity time slot region; analyzing the traffic characteristic identifier to generate a predefined time slot mapping table for the periodic real-time traffic; executing a centralized scheduling decision to dynamically allocate time slot resources; the terminal equipment carries out data receiving and transmitting in the distributed time slot; and the access point equipment collects the transmission statistics and redistributes the time slot proportion according to a statistical result. Through a time slot separation design and a pre-configuration authorization mechanism, real-time flow certainty low delay and throughput flow efficient transmission are realized, and the problems of insufficient resource utilization and uncertain delay caused by single time slot granularity and a competition mechanism are solved.

Description

Technical Field

[0001] This invention relates to the field of time division multiple access resource scheduling technology in wireless communication networks, and in particular to a real-time and throughput hybrid scheduling method for wireless TDMA based on two-layer time slot separation. Background Technology

[0002] In the Industrial Internet of Things (IIoT), wireless TDMA technology divides channel time into discrete time slots through a time division multiple access (TDMA) mechanism to manage the access of multiple devices in an orderly manner. A hybrid scheduling method based on two-layer time slot separation designs the time slot structure into two independent levels: the first level of time slots is dedicated to data transmission with high real-time requirements, such as control commands and alarm signals, to provide low latency and deterministic response; the second level of time slots is used for throughput-priority data transmission, such as batch sensor readings and log reporting, to optimize channel bandwidth utilization. The time slot separation mechanism achieves physical isolation between real-time traffic and high-throughput traffic, reducing transmission conflicts and queuing delays, thereby balancing the needs of time-sensitive tasks and high-capacity data exchange in IIoT scenarios.

[0003] Existing wireless network scheduling technologies suffer from several pain points. Specifically, in industrial IoT scenarios, wireless networks need to support both real-time control traffic and batch data traffic simultaneously. However, current technologies employ a single time-slot granularity design, meaning all traffic types use a uniform time-slot unit. This results in real-time small packet traffic, such as control commands from programmable logic controllers, occupying excessively large time slots and leading to low resource utilization. Meanwhile, batch large packet traffic, such as sensor data acquisition, requires multiple fragmented transmissions due to insufficient time slots, introducing additional overhead. Furthermore, contention-based random access mechanisms, such as carrier sense multiple access conflict avoidance, force devices to contend for channel access rights. Real-time traffic cannot receive priority scheduling, causing random delays due to conflict backoff, affecting the deterministic response of industrial equipment. In a contention-driven environment, the throughput of batch traffic is limited by decreased channel contention efficiency. For example, in industrial production lines, real-time synchronization control signals for robotic arms may experience operational synchronization failures due to contention delays. Simultaneously, the large-scale data uploads from high-resolution image sensors are slowed down due to time-slot mismatches and contention conflicts. Overall, network performance cannot meet the high reliability and efficiency requirements of industrial applications. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a hybrid real-time and throughput scheduling method for wireless TDMA based on dual-layer time slot separation, which solves the technical problems of high real-time traffic latency and low throughput efficiency caused by the use of a single time slot granularity and contention mechanism in existing wireless network scheduling.

[0005] To solve the above-mentioned technical problems, the specific contents of the present invention are as follows: This invention provides a real-time and throughput hybrid scheduling method for wireless TDMA based on two-layer time slot separation, comprising: Step 1: The access point device collects the device status parameters and traffic characteristic identifiers reported by the terminal devices; Step 2: Based on the device status parameters and traffic characteristic identifiers collected in Step 1, the access point device constructs a hierarchical time base and periodically generates frame synchronization signals including absolute time bases and micro-frame synchronization signals including relative time offsets. Step 3: Based on the frame synchronization signal and microframe synchronization signal generated in Step 2, the access point device is configured to include a transmission structure of at least one complete periodic frame. Each complete periodic frame is divided into multiple repeating microframe units. Each microframe unit contains a fast access time slot area, a deterministic time slot area, and a capacity time slot area arranged in sequence. Step 4: The access point device parses the traffic characteristic identifier collected in Step 1 and generates a predefined time slot mapping table for real-time traffic that is identified as periodic. The time slot mapping table includes fixed transmission location information bound to the terminal device identifier. Step 5: Combining the device status parameters and traffic characteristic identifiers collected in Step 1 with the transmission structure configured in Step 3, the access point device performs centralized scheduling decisions to calculate and allocate time slot resources located in the deterministic time slot area and the capacity time slot area for real-time traffic and throughput traffic respectively. Step 6: The terminal device performs data transmission and reception in the deterministic time slot area or capacity time slot area in the corresponding microframe unit according to the time slot resources allocated in step 5. Step 7: The access point device collects real-time transmission delay statistics and throughput statistics generated during the data transmission and reception process of the terminal device in Step 6. Step 8: Based on the real-time transmission delay statistics and throughput statistics collected in Step 7, the access point device redistributes the ratio of the number of time slots in the deterministic time slot area and the capacity time slot area in the subsequent complete periodic frame.

[0006] Furthermore, in the wireless TDMA real-time and throughput hybrid scheduling method based on dual-layer time slot separation described in this invention, step 1 includes: The access point device receives signaling messages sent by the terminal device during the initialization phase or when the state changes; The access point device extracts the terminal device's unique identifier, the requested traffic type identifier, and the quality of service requirement parameters from the received signaling messages; Based on the extracted unique identifier of the terminal device, the access point device aggregates and maintains the historical transmission performance records of the terminal device. The historical transmission performance records include the time slot usage success rate and data queue status of the terminal device in the historical period. The access point equipment smooths the historical transmission performance records of the aggregation and maintenance, and generates trend parameters for predicting future resource demand.

[0007] Furthermore, in the wireless TDMA real-time and throughput hybrid scheduling method based on dual-layer time slot separation described in this invention, step 2 includes: The access point device sends a frame synchronization signal at the beginning of each complete cycle frame. The frame synchronization signal carries the absolute frame sequence number and the macro resource allocation strategy. The access point device inserts a microframe synchronization signal at the start position of each microframe unit defined in step 3. The microframe synchronization signal carries the microframe index and micro-time slot allocation information. The terminal device receives the microframe synchronization signal, compares the received timestamp with the local timer value, and calculates the clock offset. The terminal device adjusts its local timer based on the calculated clock offset to align the local timer with the starting boundary of the microframe unit.

[0008] Furthermore, in the wireless TDMA real-time and throughput hybrid scheduling method based on dual-layer time slot separation described in this invention, step 3 includes: The access point device defines the duration of a complete periodic frame as a fixed value and divides the complete periodic frame into a preset number of microframe units. For each equally divided microframe unit, the access point device defines a time slot layout, in which the fast access time slot area is located in the beginning part, the deterministic time slot area is located in the middle part, and the capacity time slot area is located in the end part. The access point device defines that the size of the time slot unit included in the deterministic time slot area is smaller than the size of the time slot unit included in the capacity time slot area.

[0009] Furthermore, in the wireless TDMA real-time and throughput hybrid scheduling method based on dual-layer time slot separation described in this invention, step 5 includes: Based on the traffic characteristic identifiers collected in step 1, the access point device counts the number of real-time traffic terminal devices waiting to be scheduled and the total throughput traffic data. The access point device calculates the occupancy rate of the deterministic time slot in the current period and queries the data queue backlog of the terminal devices corresponding to the number of real-time traffic terminal devices; When the calculated occupancy rate is greater than the first threshold and a queue backlog is found, the access point device will adjust one time slot unit of the capacity time slot area to a deterministic time slot area starting from the next cycle. When the calculated occupancy rate is lower than the second threshold and no queue backlog is found, the access point device will adjust one time slot unit of the deterministic time slot area to the capacity time slot area starting from the next cycle. The access point device generates scheduling signaling including the updated time slot layout and broadcasts the scheduling signaling via the frame synchronization signal generated in step 2.

[0010] Furthermore, in the wireless TDMA real-time and throughput hybrid scheduling method based on dual-layer time slot separation described in this invention, step 6 includes: For terminal devices that have been assigned a predefined time slot mapping table in step 4, periodic data transmission and reception are performed at the designated time slot location in the deterministic time slot region; For terminal devices that are dynamically allocated capacity time slot resources in step 5, batch data transmission and reception are performed within one or more consecutively allocated capacity time slot units; In the preset management microframe, a portion of the resources in the reserved capacity time slot of the access point device is used as a random access window. The access point device receives and responds to the network access request and network exit announcement of the terminal device through the random access window.

[0011] Furthermore, in the wireless TDMA real-time and throughput hybrid scheduling method based on dual-layer time slot separation described in this invention, step 7 includes: The access point device collects end-to-end transmission delay samples of real-time traffic generated during the data transmission and reception process of the terminal device in step 6. The access point device calculates the average latency and latency jitter value based on the collected latency samples; The access point device measures the effective data transmission volume of the capacity time slot within a unit of time, which is used as the network throughput. The access point device counts the number of idle time slots in the deterministic time slot area where there is no data transmission.

[0012] Furthermore, the wireless TDMA real-time and throughput hybrid scheduling method based on dual-layer time slot separation described in this invention further includes: After the terminal device completes clock synchronization according to the microframe unit start boundary defined in step 3, it receives and parses the microframe synchronization signal generated in step 2 to obtain the micro-time slot allocation information carried by the microframe synchronization signal. Based on the parsed micro-time slot allocation information, the terminal device determines the start and end times of the fast access time slot area, deterministic time slot area, and capacity time slot area defined in step 3 in subsequent microframe units. For a terminal device that has been allocated time slot resources in step 5, the physical layer frame timing required for the terminal device to send or receive data is calculated by combining the time slot unit size defined in step 4 and the determined start and end time points. The terminal device that was allocated time slot resources in step 5, according to the macro-resource allocation strategy carried by the frame synchronization signal in step 2, associates the calculated transmission timing plan spanning multiple consecutive microframe units with the absolute frame sequence number in the frame synchronization signal, thereby generating a long-term transmission plan table.

[0013] Furthermore, in the wireless TDMA real-time and throughput hybrid scheduling method based on dual-layer time slot separation described in this invention, step 6 of data transmission and reception within the fast access time slot region, deterministic time slot region, and capacity time slot region includes: When a terminal device detects an emergency message within the fast access time slot, it sends the message directly at the start of the fast access time slot. Within the deterministic time slot region, based on the predefined time slot mapping table generated in step 4 or the dynamic allocation result in step 5, a specific time slot unit is bound to the device identifier of a specific terminal device, and terminal devices whose device identifiers are not bound are prohibited from initiating transmissions within the specific time slot unit. Within the capacity time slot area, the scheduling decision in step 5 continuously allocates one or more capacity time slot units to a specific terminal device, and the capacity time slot units are allowed to span adjacent microframe units.

[0014] Furthermore, in the wireless TDMA real-time and throughput hybrid scheduling method based on dual-layer time slot separation described in this invention, step 5 of adjusting a time slot unit of the capacity time slot region to a deterministic time slot region includes: Before generating scheduling signaling, the access point device marks a time slot unit of the capacity time slot area; Within the current cycle, the access point device sends a resource reclamation command to a terminal device using a time slot unit of the capacity time slot area through the micro-time slot allocation information carried by the micro-frame synchronization signal generated in step 2. After the transmission corresponding to a time slot unit in the capacity time slot area is completed, the access point device modifies its type identifier to a deterministic time slot area. In the frame synchronization signal generated in the next cycle, the access point device will broadcast the time slot unit with the modified type identifier as a newly added deterministic time slot resource for authorization. Step 5, which involves adjusting a time slot unit in a deterministic time slot region to a capacity time slot region, includes: The access point device identifies a time slot unit of the deterministic time slot region within the current cycle; If a terminal device bound to a time slot unit of the deterministic time slot area has no data transmission in the current period, the access point device will directly modify its type identifier to a capacity time slot area in the next period. If a terminal device bound to a time slot unit in the deterministic time slot area has data transmission in the current period, the access point device will migrate the data transmission task of the terminal device to another time slot unit in the same deterministic time slot area, and then modify the type identifier of the original time slot unit to a capacity time slot area.

[0015] Beneficial effects of this invention; This invention employs a dual-layer time-slot separation architecture, sequentially dividing each microframe unit into a fast access time slot zone, a deterministic time slot zone, and a capacity time slot zone. This achieves physical isolation between real-time traffic and throughput traffic, reducing transmission conflicts and queuing delays. Access point devices generate a predefined time slot mapping table based on collected terminal device traffic characteristic identifiers, allocating fixed transmission positions for periodic real-time traffic, avoiding scheduling request overhead and achieving zero scheduling latency. Centralized scheduling decisions dynamically adjust the time slot ratio based on device status parameters and transmission structure. When the deterministic time slot occupancy rate exceeds a threshold and queues are backlogged, real-time resources are increased; when the occupancy rate is below the threshold, throughput resources are optimized, improving resource utilization. Terminal devices transmit and receive data within allocated time slots. Access point devices collect transmission delay and throughput statistics and redistribute the time slot ratio based on the statistical results, balancing real-time requirements and throughput efficiency, thus comprehensively improving the reliability and performance of the wireless network in industrial IoT scenarios. Attached Figure Description

[0016] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the new device access process provided in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the adaptive adjustment process when adding real-time devices according to Embodiment 2 of the present invention; Figure 3 This is a schematic diagram of the emergency signal processing flow provided in Embodiment 3 of the present invention; Figure 4 This is a schematic diagram of the equipment departure and resource recycling process provided in Embodiment 4 of the present invention. Detailed Implementation

[0018] To make the technical solution of the present invention clearer, the present invention will be clearly and completely described below with reference to specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. The present invention provided by various embodiments will be described in detail below with reference to the accompanying drawings. To better understand the purpose of the present invention, the present invention will be described in further detail below.

[0019] Please see Figures 1 to 4 This invention provides a real-time and throughput hybrid scheduling method for wireless TDMA based on two-layer time slot separation, comprising: Step 1: The access point device collects the device status parameters and traffic characteristic identifiers reported by the terminal devices; Step 2: Based on the device status parameters and traffic characteristic identifiers collected in Step 1, the access point device constructs a hierarchical time base and periodically generates frame synchronization signals including absolute time bases and micro-frame synchronization signals including relative time offsets. Step 3: Based on the frame synchronization signal and microframe synchronization signal generated in Step 2, the access point device is configured to include a transmission structure of at least one complete periodic frame. Each complete periodic frame is divided into multiple repeating microframe units. Each microframe unit contains a fast access time slot area, a deterministic time slot area, and a capacity time slot area arranged in sequence. Step 4: The access point device parses the traffic characteristic identifier collected in Step 1 and generates a predefined time slot mapping table for real-time traffic that is identified as periodic. The time slot mapping table includes fixed transmission location information bound to the terminal device identifier. Step 5: Combining the device status parameters and traffic characteristic identifiers collected in Step 1 with the transmission structure configured in Step 3, the access point device performs centralized scheduling decisions to calculate and allocate time slot resources located in the deterministic time slot area and the capacity time slot area for real-time traffic and throughput traffic respectively. Step 6: The terminal device performs data transmission and reception in the deterministic time slot area or capacity time slot area in the corresponding microframe unit according to the time slot resources allocated in step 5. Step 7: The access point device collects real-time transmission delay statistics and throughput statistics generated during the data transmission and reception process of the terminal device in Step 6. Step 8: Based on the real-time transmission delay statistics and throughput statistics collected in Step 7, the access point device redistributes the ratio of the number of time slots in the deterministic time slot area and the capacity time slot area in the subsequent complete periodic frame.

[0020] When the access point device starts up, it collects signaling messages sent by terminal devices during the initialization phase or state change, extracting the terminal device's unique identifier, requested traffic type identifier, and quality of service (QoS) requirement parameters from these messages. Based on the extracted terminal device's unique identifier, the access point device aggregates and maintains the terminal device's historical transmission performance records, including time slot utilization success rate and data queue status, and performs smoothing processing on these historical transmission performance records to generate trend parameters for predicting future resource demands. This data collection process provides fundamental data support for subsequent resource scheduling.

[0021] Based on the collected device status parameters and traffic characteristic identifiers, the access point device constructs a hierarchical time base. At the beginning of each complete frame cycle, it sends a frame synchronization signal, carrying the absolute frame sequence number and macro-level resource allocation strategy. The access point device inserts a microframe synchronization signal at the beginning of each microframe unit, carrying the microframe index and micro-level time slot allocation information. After receiving the microframe synchronization signal, the terminal device compares the received timestamp with its local timer value, calculates the clock offset, and corrects its local timer accordingly. This aligns the terminal device's local timer with the starting boundary of the microframe unit, thereby establishing high-precision time synchronization.

[0022] Based on the generated frame synchronization signal and microframe synchronization signal, the access point device configures a transmission structure including at least one complete periodic frame. The duration of the complete periodic frame is fixed and it is divided into a preset number of microframe units. For each microframe unit, the access point device defines a timeslot layout in which the fast access timeslot area is located at the beginning, the deterministic timeslot area is located in the middle, and the capacity timeslot area is located at the end. The access point device defines that the timeslot unit size included in the deterministic timeslot area is smaller than the timeslot unit size included in the capacity timeslot area to accommodate the transmission requirements of different traffic types.

[0023] The access point device parses and collects traffic characteristic identifiers, and generates a predefined time slot mapping table for real-time traffic identified as periodic. The time slot mapping table includes fixed transmission location information bound to the terminal device identifier. This pre-configuration mechanism allows the terminal device to automatically send data at a predetermined time without additional scheduling requests, achieving transmission efficiency with zero scheduling latency.

[0024] Based on the collected device status parameters, traffic characteristic identifiers, and configured transmission structure, the access point device executes centralized scheduling decisions, and counts the number of real-time traffic terminal devices waiting for scheduling and the total throughput data. The access point device calculates the occupancy rate of the deterministic time slot in the current cycle and queries the data queue backlog status of the terminal devices corresponding to the number of real-time traffic terminal devices. When the occupancy rate is greater than the first threshold and there is a queue backlog, the access point device adjusts one time slot unit of the capacity time slot to a deterministic time slot starting from the next cycle; when the occupancy rate is lower than the second threshold and there is no queue backlog, the access point device adjusts one time slot unit of the deterministic time slot to a capacity time slot starting from the next cycle. The access point device generates scheduling signaling including the updated time slot layout and broadcasts the scheduling signaling through frame synchronization signals to achieve dynamic resource allocation.

[0025] Terminal devices perform data transmission and reception within the deterministic time slot area or capacity time slot area in the corresponding microframe unit, based on the allocated time slot resources. For terminal devices with predefined time slot mapping tables, periodic data transmission and reception are performed at the designated time slot position in the deterministic time slot area; for terminal devices dynamically allocated to capacity time slot area resources, batch data transmission and reception are performed within one or more consecutively allocated capacity time slot units. In the preset management microframe, the access point device reserves a portion of the capacity time slot area resources as a random access window, receiving and responding to the terminal device's network entry request and network exit announcement through the random access window, supporting dynamic device management.

[0026] Access point devices collect real-time transmission delay and throughput statistics generated during the data transmission and reception process of terminal devices. These statistics include real-time end-to-end transmission delay samples, average delay and delay jitter values, and the effective data transmission volume per unit time in the capacity time slot as network throughput. Access point devices also count the number of idle time slots with no data transmission in the deterministic time slot area, providing a basis for subsequent adjustments.

[0027] Based on the collected real-time transmission delay and throughput statistics, the access point device reallocates the ratio of deterministic time slots to capacity time slots in subsequent complete periodic frames. This adaptive adjustment process, based on the statistical results of complete periodic frames, progressively modifies the time slot ratio to balance the resource requirements of real-time traffic and throughput traffic, thereby improving overall network performance.

[0028] In step 1, the access point device receives signaling messages actively sent by the terminal device during initialization or state changes by listening to the wireless channel. These messages are encapsulated in a specific format, including device identification and traffic demand information. The access point device parses the payload of the signaling message, extracting the terminal device's unique identifier, the requested traffic type identifier, and quality of service (QoS) requirements. The traffic type identifier distinguishes between real-time traffic and throughput traffic, and the QoS requirements include latency limits and bandwidth requirements. The access point device indexes its internal database based on the terminal device's unique identifier, aggregating the device's historical transmission performance records. These records cover the time slot utilization success rate and data queue status within the historical period. The time slot utilization success rate reflects transmission reliability, and the data queue status indicates the amount of cached data. The access point device applies a sliding window algorithm to smooth the historical transmission performance records, filtering out short-term fluctuations and generating trend parameters for predicting future resource demands. These trend parameters include the time slot demand growth rate and queue change trends, providing data support for subsequent scheduling decisions.

[0029] In step 2, the access point device constructs a hierarchical time base, generating and sending a frame synchronization signal at the beginning of each complete periodic frame. This frame synchronization signal carries the absolute frame sequence number and a macro-level resource allocation strategy; the absolute frame sequence number provides a global time reference. The access point device inserts a microframe synchronization signal at the beginning of each microframe unit. This microframe synchronization signal includes a microframe index and micro-level time slot allocation information; the microframe index locates the microframe's position within the complete periodic frame. After receiving the microframe synchronization signal, the terminal device parses the signal content, compares the received timestamp with its local timer value, and calculates the clock offset. The clock offset reflects the time difference between devices. Based on the calculated clock offset, the terminal device uses a linear correction algorithm to adjust its local timer, aligning the terminal device's local timer with the starting boundary of the microframe unit, achieving high-precision time synchronization and reducing transmission timing errors.

[0030] Step 3 involves transmission structure configuration. The access point device defines the duration of a complete periodic frame as a fixed value and divides the complete periodic frame into a preset number of microframe units. The microframe units have consistent periods to ensure timing regularity. The access point device defines a timeslot layout for each microframe unit. In the timeslot layout, the fast access timeslot area is located at the beginning and is used for emergency message transmission; the deterministic timeslot area is located in the middle and allocated to real-time traffic; and the capacity timeslot area is located at the end and serves throughput traffic. The access point device sets the size of the timeslot units included in the deterministic timeslot area to be smaller than the size of the timeslot units included in the capacity timeslot area. The smaller timeslot units match the small packet characteristics of real-time traffic, reducing transmission latency, while the larger timeslot units adapt to the large data volume transmission of throughput traffic, improving efficiency.

[0031] Step 5 executes centralized scheduling decisions. The access point device (APD) uses collected traffic characteristics to statistically analyze the number of real-time traffic terminal devices waiting for scheduling and the total throughput data. The number of real-time traffic terminal devices affects the allocation of deterministic time slots, while the total throughput data determines the demand for capacity time slots. The APD calculates the occupancy rate of the deterministic time slots in the current cycle, based on time slot usage, and queries the data queue backlog status of terminal devices corresponding to the number of real-time traffic terminal devices. Queue backlog represents the amount of data to be transmitted. When the occupancy rate is greater than the first threshold and there is queue backlog, the APD adjusts one time slot unit of the capacity time slot to a deterministic time slot starting from the next cycle, increasing real-time resource allocation. When the occupancy rate is lower than the second threshold and there is no queue backlog, the APD adjusts one time slot unit of the deterministic time slot to a capacity time slot starting from the next cycle, optimizing throughput performance. The APD generates scheduling signaling including the updated time slot layout. The scheduling signaling encapsulates the new time slot allocation information and broadcasts it to all terminal devices via frame synchronization signals, achieving dynamic resource adjustment.

[0032] Step 6: The terminal device performs data transmission and reception operations according to the time slot resources allocated by the access point device. Terminal devices with predefined time slot mapping tables perform periodic data transmission and reception at fixed time slot locations within a deterministic time slot zone. This method avoids the overhead of scheduling requests and directly utilizes pre-configured time slots to transmit real-time traffic, such as sensor data reporting in industrial control. Terminal devices dynamically allocated to capacity time slot zones perform batch data transmission and reception within one or more consecutively allocated capacity time slot units. Capacity time slot units are larger, suitable for transmitting large amounts of data such as logs or images, reducing the number of fragmentation operations. In a preset management microframe, the access point device reserves a portion of the capacity time slot zone resources as a random access window. This window uses a contention mechanism, allowing new terminal devices to send network entry requests or network exit notices. The access point device listens to the window and responds to management signaling, supporting dynamic access and departure of network devices.

[0033] Step 6 embodies the differentiated utilization of time slot resources. A predefined mapping table ensures the determinism of real-time traffic, dynamic allocation optimizes throughput efficiency, and random access windows handle network topology changes. The operation relies on the time slot mapping table generated in step 4 and the dynamic scheduling results in step 5, ensuring that resource allocation matches traffic characteristics.

[0034] In step 7, the access point device collects performance statistics generated during the data transmission and reception process of the terminal devices. Real-time traffic end-to-end transmission delay samples are calculated using timestamp records. The access point device calculates the average delay and delay jitter values ​​based on these samples to evaluate the timeliness of real-time traffic. The effective data transmission volume in the capacity time slot area is measured per unit time and serves as a network throughput indicator, reflecting the transmission efficiency of batch traffic. The number of idle time slots with no data transmission in the deterministic time slot area is counted to identify resource waste. These statistics, based on the actual transmission data from step 6, provide a basis for resource reallocation in step 8.

[0035] The statistical data collection process is integrated within the data transmission cycle. Access point devices automatically aggregate latency and throughput data using the counting information carried by the frame synchronization signal. A sliding window algorithm is used to smooth short-term fluctuations when calculating the average latency, and latency jitter is obtained through variance analysis. Throughput measurement focuses on the payload, excluding protocol overhead. Idle time slot statistics identify unused deterministic resources, and these metrics collectively characterize the network load status.

[0036] After clock synchronization is completed at the start boundary of a microframe unit, the terminal device receives and parses the microframe synchronization signal, extracting micro-time slot allocation information, including time zone boundaries and time slot indices. Following parsing, the terminal device determines the start and end times of the fast access time slot, deterministic time slot, and capacity time slot in subsequent microframe units, calculated based on the relative timestamps of the microframe synchronization signal. For terminal devices with allocated time slot resources, the device calculates the transmission or reception timing of physical layer frames, such as frame intervals and modulation timing, by combining the time slot unit size and time zone boundaries. Based on the macro-resource allocation strategy carried by the frame synchronization signal, the terminal device associates the transmission timing plan spanning multiple microframe units with absolute frame sequence numbers, generating a long-term transmission plan table to guide multi-cycle data transmission.

[0037] This step enhances the accuracy of time synchronization. The microframe synchronization signal provides frequent clock calibration to avoid drift accumulation. Timing calculations ensure that the device activates the transceiver circuits at the correct time, reducing collisions. The long-term schedule supports continuous transmission across frames, improving throughput efficiency. Together with the scheduling decision in step 5, it achieves resource reservation and timing alignment.

[0038] Within the fast access time slot area, when a terminal device detects an urgent message such as a security alarm, it sends it directly at the start of the time slot without waiting for authorization, ensuring a low-latency response. Within the deterministic time slot area, based on a predefined time slot mapping table or dynamic allocation results, specific time slot units are bound to terminal device identifiers. After binding, other devices are prohibited from transmitting within that time slot unit, forming a dedicated channel. Within the capacity time slot area, scheduling decisions allocate a group of consecutive time slot units to terminal devices. These units can span adjacent microframe units, forming large transmission windows and reducing handover overhead.

[0039] This design differentiates traffic priorities, enabling rapid access to time slots to handle sudden emergencies, ensuring the isolation of real-time traffic through deterministic time slots, and optimizing batch transmission through capacity time slots. A binding mechanism prevents interference, and continuous allocation improves throughput performance. Consistent with the time slot layout in step 3, it meets the mixed needs of industrial scenarios.

[0040] When adjusting a time slot unit in a capacity time slot region to a deterministic time slot region, the access point device first marks the time slot unit in the capacity time slot region. Then, using the micro-time slot allocation information carried in the micro-frame synchronization signal, it sends a resource reclamation command to the terminal device using that time slot unit, specifying the migration time point. After the corresponding transmission of the unit ends, the access point device modifies its type identifier to a deterministic time slot region and broadcasts authorization in the next periodic frame synchronization signal to make the new resource effective. When adjusting a time slot unit in a deterministic time slot region to a capacity time slot region, the access point device identifies the time slot unit in the deterministic time slot region. If the device bound to the time slot unit in the deterministic time slot region has no data transmission, it directly modifies the type identifier; if there is data transmission, it migrates the task to another time slot unit in the same region and then modifies the identifier. The migration process ensures data continuity.

[0041] The adjustment process dynamically optimizes resource allocation based on the statistical feedback from step 7. Resource reclamation commands prevent transmission interruptions, and migration mechanisms ensure uninterrupted service. Broadcast authorization notifies all devices of the change, maintaining network consistency. This gradual adjustment balances real-time and throughput demands, improving resource utilization.

[0042] In industrial IoT scenarios, wireless networks need to support both real-time control traffic and batch data traffic simultaneously. However, existing technologies employ a single time-slot granularity design, resulting in low utilization of real-time small packet traffic resources and poor transmission efficiency of batch large packet traffic. Contention-based random access mechanisms introduce random latency, affecting deterministic response. This invention provides a wireless TDMA hybrid scheduling method based on dual-layer time-slot separation, addressing the aforementioned problems through time-slot resource isolation and dynamic allocation.

[0043] After the access point device starts up, it first collects the device status parameters and traffic characteristic identifiers reported by the terminal devices. In a smart factory environment, terminal devices such as PLC controllers and sensors send signaling messages during the initialization phase. The access point parses these messages to extract the device's unique identifier, traffic type identifier, and quality of service (QoS) requirement parameters. The access point maintains historical transmission performance records, including time slot utilization success rate and data queue status, and generates trend parameters through smoothing processing to predict resource demand.

[0044] Based on the collected data, the access point constructs a hierarchical time base and generates frame synchronization signals and microframe synchronization signals. The frame synchronization signal carries the absolute frame sequence number and macro-level resource strategy, while the microframe synchronization signal provides microframe index and micro-level time slot allocation information. After receiving the synchronization signal, the terminal device calibrates its local clock to align with the start boundary of the microframe unit, achieving high-precision time synchronization.

[0045] The access point configures the transmission structure, dividing a complete periodic frame into multiple microframe units. Within each microframe unit, a fast access timeslot area, a deterministic timeslot area, and a capacity timeslot area are arranged sequentially. The fast access timeslot area is located at the beginning and is used for urgent messages; the deterministic timeslot area is in the middle and allocated to real-time traffic; the capacity timeslot area is at the end and serves throughput traffic. The timeslot unit size within the deterministic timeslot area is smaller than that within the capacity timeslot area, matching different traffic characteristics.

[0046] A predefined time slot mapping table is generated for periodic real-time traffic, binding device identifiers to fixed transmission locations. During the device association phase, the access point parses the traffic identifier, allocates a fixed time slot location, and the terminal device automatically sends data at the predetermined time, without the need for scheduling requests, achieving zero scheduling latency. For example, the periodic heartbeat packets of a PLC controller are transmitted directly in the designated time slot, avoiding contention overhead.

[0047] The access point executes centralized scheduling decisions, counts the number of real-time devices and the total data throughput, calculates the deterministic time slot occupancy rate, and queries queue backlog status. When the occupancy rate exceeds a threshold and backlog exists, one time slot unit in the capacity time slot area is adjusted to a deterministic time slot area; when the occupancy rate is below the threshold and there is no backlog, the adjustment is reversed. Scheduling signaling is broadcast via frame synchronization signals to achieve dynamic resource allocation. In production line expansion scenarios, the addition of new real-time devices triggers adaptive adjustments, gradually optimizing the time slot ratio and avoiding system oscillations.

[0048] Terminal devices send and receive data within their respective time slots based on allocated resources. Devices with pre-configured mapping tables transmit periodically in deterministic time slots, while dynamically allocated devices transmit in batches in capacity time slots. In management microframes, access points reserve random access windows to handle network entry requests and network exit announcements, supporting dynamic device management.

[0049] The access point collects transmission delay samples and throughput statistics, calculates average latency, latency jitter, and network throughput, and counts the number of idle time slots. Based on the statistical results, the access point reallocates the proportion of time slots for subsequent complete periodic frames to balance real-time and throughput requirements. For example, when real-time time slots are idle, resources are elastically lent to throughput time slots to improve utilization.

[0050] In security monitoring scenarios, when a terminal device detects an emergency message, it sends it directly at the start of the fast access time slot without authorization, ensuring a low-latency response. The access point receives the signal and quickly broadcasts its response, significantly reducing processing latency. This process reflects the priority design of the fast access time slot. The emergency signal processing flow is as follows: Figure 3 As shown, this demonstrates the direct transmission mechanism of terminal devices in the fast access time slot area.

[0051] When a device leaves the network, the access point receives a network exit notification through a random access window and identifies the time slot units to be released. If there is no data transmission, the type identifier is directly modified; if there is data, adjustments are made after the migration task. The resource reclamation process combines statistical monitoring to gradually adjust the time slot ratio, improving overall efficiency. For example, when some real-time devices disconnect, idle time slots are reallocated to throughput traffic to clear queue backlogs.

[0052] This invention achieves deterministic latency and high throughput efficiency for real-time traffic in industrial IoT scenarios through two-layer time slot separation, pre-configured authorization, and dynamic scheduling, solving the technical problems caused by single time slot granularity and competition mechanism.

[0053] Example 1, please refer to the appendix. Figure 1 In the smart factory scenario of Industrial Internet of Things (IIoT), after the access point device starts up, it executes step 1. The access point collects signaling messages reported by terminal devices such as PLC controllers and sensors during initialization via a listening channel, extracts the device's unique identifier, traffic type identifier (such as real-time control commands or batch data), and quality of service parameters, and maintains historical transmission records, including time slot utilization success rate and data queue status. Trend parameters are generated using a sliding window algorithm. Step 2: The access point constructs a hierarchical time base, sending a frame synchronization signal at the beginning of each 10ms full frame, carrying the absolute frame sequence number and macro-resource strategy. A microframe synchronization signal is inserted at the beginning of each 1ms microframe unit. The terminal device receives this signal, calculates the clock offset, and corrects its local timer to achieve synchronization. Step 3: The access point configures the transmission structure, dividing the full frame into 10 microframe units. Each microframe adopts a uniform layout: a fast access time slot area (fixed 110μs), a deterministic time slot area (configurable 220-660μs), and a capacity time slot area (remaining time slots). The deterministic time slot unit is smaller than the capacity time slot unit. Step 4: The access point parses the traffic identifier, generates a predefined timeslot mapping table for periodic real-time traffic, and binds the device ID to a fixed timeslot location, such as allocating a deterministic timeslot area of ​​a specific microframe to the PLC heartbeat packet. Step 5: The access point performs centralized scheduling, counts the number of real-time devices and the total throughput, calculates the deterministic timeslot occupancy rate, and when it exceeds the 80% threshold and queue backlog occurs, it adjusts one timeslot unit of the capacity timeslot area to a deterministic timeslot area in the next cycle, and broadcasts the updated scheduling signaling through the frame synchronization signal. Step 6: Terminal devices send and receive data according to the allocated resources. For example, real-time devices send in predefined timeslots, and throughput devices transmit in batches in consecutive capacity timeslot units. Random access windows are reserved in the management microframes to handle network access requests. Step 7: The access point collects real-time transmission delay samples and throughput statistics, and calculates the average delay and the number of idle timeslots. Step 8: Based on the statistical results, the timeslot ratio is adjusted, for example, reducing idle deterministic timeslots to increase capacity resources.

[0054] Example 2, please refer to the appendix. Figure 2 For an industrial production line expansion scenario, the initial network has 3 PLC controllers and 10 data acquisition units, configured with a deterministic time slot area of ​​2 units (220μs) and a capacity time slot area of ​​6 units (660μs), with each PLC receiving approximately 73μs of time slots. After an event is triggered, 5 new PLCs are connected, increasing the number of real-time devices to 8. The access point detects that the deterministic time slot area occupancy rate increases from 70% to 95% and there is a backlog of 3 data packets in the queue, meeting the threshold condition (occupancy rate exceeding 80% and backlog). The access point calculates the current complete frame statistics and broadcasts an adjustment command in the Beacon of microframe 0, increasing the deterministic time slot area to 3 units (330μs) and decreasing the capacity time slot area to 5 units (550μs), with an adjustment increment of ±1 unit to avoid oscillation. After receiving the signaling, the terminal devices realign the time slots, with each PLC receiving approximately 41μs of resources, meeting real-time requirements; simultaneously, the throughput devices adapt to the compressed time slots to maintain throughput efficiency. The adjustment process is based on collected data, such as real-time utilization and queue length, and is linked to long-term transmission plans through frame synchronization signals. This demonstrates the support of dynamic resource reallocation for the resilience of industrial networks and solves the technical problem that fixed allocation cannot adapt to changes in traffic.

[0055] Example 3, please refer to the appendix. Figure 3 In a safety monitoring scenario, when the PLC controller detects an anomaly in the robotic arm and needs to send an emergency stop signal, the terminal device immediately sends alarm data at the start of the fast access time slot (fixed at 110μs) of the current microframe, without requiring pre-configuration authorization. After receiving the signal, the access point broadcasts a response in the next available time slot, with a processing delay of less than 1ms. This process relies on time slot design, with the fast access time slot having the highest priority, prohibiting unbound devices from occupying it; the access point manages time slot binding through microframe synchronization signals to ensure isolated transmission of emergency traffic. Simultaneously, a predefined time slot mapping table is used for periodic traffic, such as regular PLC data, while burst traffic is handled through a fast response mechanism. The terminal device determines the time zone boundary and calculates the physical layer frame timing based on the parsed micro-time slot allocation information.

[0056] Example 4, please refer to the appendix. Figure 4When five PLC controllers in the industrial network disconnect, the access point receives the disconnection notification through a reserved random access window within the capacity time slot area of ​​microframe 0, identifying a time slot unit in the deterministic time slot area. If the bound device has no data transmission, the access point directly changes the time slot type to the capacity time slot area in the next cycle; if there is data, the transmission task is migrated to another time slot in the same area and the identifier is modified. For example, if the utilization rate of the initial real-time time slot area of ​​5 units (550μs) drops to 40%, the access point calculates the trend based on the collected idle time slot statistics at the end of the complete frame, gradually adjusting the deterministic time slot area to 3 units (330μs) and increasing the capacity time slot area to 5 units (550μs), so that the remaining three PLCs each obtain 110μs of resources. The terminal equipment updates the long-term transmission plan table according to the Beacon notification, and the throughput equipment uses the newly added capacity time slots to digest the queue backlog.

Claims

1. A real-time and throughput hybrid scheduling method for wireless TDMA based on two-layer time slot separation, characterized in that, include: Step 1: The access point device collects the device status parameters and traffic characteristic identifiers reported by the terminal devices; Step 2: Based on the device status parameters and traffic characteristic identifiers collected in Step 1, the access point device constructs a hierarchical time base and periodically generates frame synchronization signals including absolute time bases and micro-frame synchronization signals including relative time offsets. Step 3: Based on the frame synchronization signal and microframe synchronization signal generated in Step 2, the access point device is configured to include a transmission structure of at least one complete periodic frame. Each complete periodic frame is divided into multiple repeating microframe units. Each microframe unit contains a fast access time slot area, a deterministic time slot area, and a capacity time slot area arranged in sequence. Step 4: The access point device parses the traffic characteristic identifier collected in Step 1 and generates a predefined time slot mapping table for real-time traffic that is identified as periodic. The time slot mapping table includes fixed transmission location information bound to the terminal device identifier. Step 5: Combining the device status parameters and traffic characteristic identifiers collected in Step 1 with the transmission structure configured in Step 3, the access point device performs centralized scheduling decisions to calculate and allocate time slot resources located in the deterministic time slot area and the capacity time slot area for real-time traffic and throughput traffic respectively. Step 6: The terminal device performs data transmission and reception in the deterministic time slot area or capacity time slot area in the corresponding microframe unit according to the time slot resources allocated in step 5. Step 7: The access point device collects real-time transmission delay statistics and throughput statistics generated during the data transmission and reception process of the terminal device in Step 6. Step 8: Based on the real-time transmission delay statistics and throughput statistics collected in Step 7, the access point device redistributes the ratio of the number of time slots in the deterministic time slot area and the capacity time slot area in the subsequent complete periodic frame.

2. The wireless TDMA real-time and throughput hybrid scheduling method based on dual-layer time slot separation according to claim 1, characterized in that, Step 1 includes: The access point device receives signaling messages sent by the terminal device during the initialization phase or when the state changes; The access point device extracts the terminal device's unique identifier, the requested traffic type identifier, and the quality of service requirement parameters from the received signaling messages; Based on the extracted unique identifier of the terminal device, the access point device aggregates and maintains the historical transmission performance records of the terminal device. The historical transmission performance records include the time slot usage success rate and data queue status of the terminal device in the historical period. The access point equipment smooths the historical transmission performance records of the aggregation and maintenance, and generates trend parameters for predicting future resource demand.

3. The wireless TDMA real-time and throughput hybrid scheduling method based on dual-layer time slot separation according to claim 2, characterized in that, Step 2 includes: The access point device sends a frame synchronization signal at the beginning of each complete cycle frame. The frame synchronization signal carries the absolute frame sequence number and the macro resource allocation strategy. The access point device inserts a microframe synchronization signal at the start position of each microframe unit defined in step 3. The microframe synchronization signal carries the microframe index and micro-time slot allocation information. The terminal device receives the microframe synchronization signal, compares the received timestamp with the local timer value, and calculates the clock offset. The terminal device adjusts its local timer based on the calculated clock offset to align the local timer with the starting boundary of the microframe unit.

4. The wireless TDMA real-time and throughput hybrid scheduling method based on dual-layer time slot separation according to claim 3, characterized in that, Step 3 includes: The access point device defines the duration of a complete periodic frame as a fixed value and divides the complete periodic frame into a preset number of microframe units. For each equally divided microframe unit, the access point device defines a time slot layout, in which the fast access time slot area is located in the beginning part, the deterministic time slot area is located in the middle part, and the capacity time slot area is located in the end part. The access point device defines that the size of the time slot unit included in the deterministic time slot area is smaller than the size of the time slot unit included in the capacity time slot area.

5. The wireless TDMA real-time and throughput hybrid scheduling method based on dual-layer time slot separation according to claim 4, characterized in that, Step 5 includes: Based on the traffic characteristic identifiers collected in step 1, the access point device counts the number of real-time traffic terminal devices waiting to be scheduled and the total throughput traffic data. The access point device calculates the occupancy rate of the deterministic time slot in the current period and queries the data queue backlog of the terminal devices corresponding to the number of real-time traffic terminal devices; When the calculated occupancy rate is greater than the first threshold and a queue backlog is found, the access point device will adjust one time slot unit of the capacity time slot area to a deterministic time slot area starting from the next cycle. When the calculated occupancy rate is lower than the second threshold and no queue backlog is found, the access point device will adjust one time slot unit of the deterministic time slot area to the capacity time slot area starting from the next cycle. The access point device generates scheduling signaling including the updated time slot layout and broadcasts the scheduling signaling via the frame synchronization signal generated in step 2.

6. The wireless TDMA real-time and throughput hybrid scheduling method based on dual-layer time slot separation according to claim 5, characterized in that, Step 6 includes: For terminal devices that have been assigned a predefined time slot mapping table in step 4, periodic data transmission and reception are performed at the designated time slot location in the deterministic time slot region; For terminal devices that are dynamically allocated capacity time slot resources in step 5, batch data transmission and reception are performed within one or more consecutively allocated capacity time slot units; In the preset management microframe, a portion of the resources in the reserved capacity time slot of the access point device is used as a random access window. The access point device receives and responds to the network access request and network exit announcement of the terminal device through the random access window.

7. The wireless TDMA real-time and throughput hybrid scheduling method based on dual-layer time slot separation according to claim 6, characterized in that, Step 7 includes: The access point device collects end-to-end transmission delay samples of real-time traffic generated during the data transmission and reception process of the terminal device in step 6. The access point device calculates the average latency and latency jitter value based on the collected latency samples; The access point device measures the effective data transmission volume of the capacity time slot within a unit of time, which is used as the network throughput. The access point device counts the number of idle time slots in the deterministic time slot area where there is no data transmission.

8. The wireless TDMA real-time and throughput hybrid scheduling method based on dual-layer time slot separation according to claim 7, characterized in that, Also includes: After the terminal device completes clock synchronization according to the microframe unit start boundary defined in step 3, it receives and parses the microframe synchronization signal generated in step 2 to obtain the micro-time slot allocation information carried by the microframe synchronization signal. Based on the parsed micro-time slot allocation information, the terminal device determines the start and end times of the fast access time slot area, deterministic time slot area, and capacity time slot area defined in step 3 in subsequent microframe units. For a terminal device that has been allocated time slot resources in step 5, the physical layer frame timing required for the terminal device to send or receive data is calculated by combining the time slot unit size defined in step 4 and the determined start and end time points. The terminal device that was allocated time slot resources in step 5, according to the macro-resource allocation strategy carried by the frame synchronization signal in step 2, associates the calculated transmission timing plan spanning multiple consecutive microframe units with the absolute frame sequence number in the frame synchronization signal, thereby generating a long-term transmission plan table.

9. The wireless TDMA real-time and throughput hybrid scheduling method based on dual-layer time slot separation according to claim 8, characterized in that, Step 6, which involves data transmission and reception within the fast access time slot, deterministic time slot, and capacity time slot, includes: When a terminal device detects an emergency message within the fast access time slot, it sends the message directly at the start of the fast access time slot. Within the deterministic time slot region, based on the predefined time slot mapping table generated in step 4 or the dynamic allocation result in step 5, a specific time slot unit is bound to the device identifier of a specific terminal device, and terminal devices whose device identifiers are not bound are prohibited from initiating transmissions within the specific time slot unit. Within the capacity time slot area, the scheduling decision in step 5 continuously allocates one or more capacity time slot units to a specific terminal device, and the capacity time slot units are allowed to span adjacent microframe units.

10. The wireless TDMA real-time and throughput hybrid scheduling method based on dual-layer time slot separation according to claim 9, characterized in that, Step 5, adjusting a time slot unit of the capacity time slot region to a deterministic time slot region, includes: Before generating scheduling signaling, the access point device marks a time slot unit of the capacity time slot area; Within the current cycle, the access point device sends a resource reclamation command to a terminal device using a time slot unit of the capacity time slot area through the micro-time slot allocation information carried by the micro-frame synchronization signal generated in step 2. After the transmission corresponding to a time slot unit in the capacity time slot area is completed, the access point device modifies its type identifier to a deterministic time slot area. In the frame synchronization signal generated in the next cycle, the access point device will broadcast the time slot unit with the modified type identifier as a newly added deterministic time slot resource for authorization. Step 5, which involves adjusting a time slot unit in a deterministic time slot region to a capacity time slot region, includes: The access point device identifies a time slot unit of the deterministic time slot region within the current cycle; If a terminal device bound to a time slot unit of the deterministic time slot area has no data transmission in the current period, the access point device will directly modify its type identifier to a capacity time slot area in the next period. If a terminal device bound to a time slot unit in the deterministic time slot area has data transmission in the current period, the access point device will migrate the data transmission task of the terminal device to another time slot unit in the same deterministic time slot area, and then modify the type identifier of the original time slot unit to a capacity time slot area.

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