A wireless TDMA real-time and throughput mixed scheduling method based on double-layer time slot separation

Abstract

The present application relates to the technical field of time division multiple access resource scheduling in wireless communication network, especially to a wireless TDMA real-time and throughput mixed scheduling method based on double-layer time slot separation, comprising access point device data; constructing layered time reference based on collected data, periodically generating frame synchronization signal and microframe synchronization signal; configuring transmission structure including fast access time slot area, deterministic time slot area and capacity time slot area; analyzing traffic characteristic identification to generate predefined time slot mapping table for periodic real-time traffic; executing centralized scheduling decision to dynamically allocate time slot resources; terminal device performs data transceiving in allocated time slot; access point device collects transmission statistics and reallocates time slot proportion according to statistical results. Through time slot separation design and pre-configuration authorization mechanism, real-time traffic deterministic low delay and throughput traffic efficient transmission are realized, and the problems of insufficient resource utilization and uncertain delay caused by single time slot granularity and competition mechanism are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of time division multiple access resource scheduling in wireless communication networks, and in particular to a wireless TDMA real-time and throughput hybrid scheduling method based on double-layer time slot separation. BACKGROUND

[0002] In industrial Internet of Things, wireless TDMA technology divides channel time into discrete time slots through time division multiple access mechanism to orderly manage multi-device access. The hybrid scheduling method based on double-layer time slot separation designs time slot structure into two independent levels: the first level time slot is specially allocated to high real-time requirement data transmission such as control instruction and alarm signal to provide low delay and deterministic response; the second level time slot is used for throughput priority data transmission such as batch sensor reading and log reporting to optimize channel bandwidth utilization. The time slot separation mechanism realizes the physical isolation of real-time traffic and high-throughput traffic, reduces transmission conflict and queuing delay, and balances the needs of time-sensitive tasks and large-capacity data exchange in industrial Internet of Things scenarios.

[0003] The existing wireless network scheduling technology has the following technical pain points: in the industrial Internet of Things scenario, the wireless network needs to support real-time control traffic and batch data traffic at the same time, but the existing technology uses single time slot granularity design, that is, all traffic types use uniform size time slot units, which leads to low resource utilization of real-time small packet traffic such as programmable logic controller control commands occupying too large time slots, and batch large packet traffic such as sensor data collection requiring multiple fragmentation transmission due to too small time slots and introducing additional overhead. At the same time, the random access mechanism based on competition such as carrier sense multiple access collision avoidance makes devices have to compete for channel access rights, real-time traffic cannot obtain priority scheduling, causing random delay due to conflict avoidance, affecting the deterministic response of industrial devices, and batch traffic throughput is limited by the decline of channel contention efficiency in the competition environment. For example, the real-time synchronous control signal of the mechanical arm in the industrial production line may cause operation out of step due to competition delay, and the large amount of data upload of high-resolution image sensors is slow due to time slot mismatch and competition conflict, and the overall network performance cannot meet the high reliability and high efficiency requirements of industrial applications. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a wireless TDMA real-time and throughput hybrid scheduling method based on double-layer time slot separation, which solves the technical problems of high real-time traffic delay and low throughput efficiency caused by the single time slot granularity and competition mechanism of the existing wireless network scheduling.

[0005] To solve the above technical problems, the specific content of the present application is as follows:

[0006] The application provides a wireless TDMA real-time and throughput hybrid scheduling method based on double-layer time slot separation, comprising:

[0007] Step 1, the access point device collects the device state parameters and traffic characteristic identifiers reported by the terminal device;

[0008] Step 2, based on the device state parameters and traffic characteristic identifiers collected in step 1, the access point device constructs a hierarchical time reference and periodically generates a frame synchronization signal including an absolute time reference and a microframe synchronization signal including a relative time offset;

[0009] Step 3, based on the frame synchronization signal and the microframe synchronization signal generated in step 2, the access point device configures a transmission structure including at least one complete cycle frame, each complete cycle frame is divided into a plurality of repeated microframe units, and each microframe unit sequentially arranges a fast access time slot area, a deterministic time slot area and a capacity time slot area;

[0010] Step 4, the access point device analyzes the traffic characteristic identifiers collected in step 1, generates a predefined time slot mapping table for the periodic real-time traffic, and the time slot mapping table includes fixed transmission location information bound with the terminal device identifier;

[0011] Step 5, comprehensively considering the device state parameters and traffic characteristic identifiers collected in step 1 and the transmission structure configured in step 3, the access point device performs a centralized scheduling decision, calculates and allocates time slot resources in the deterministic time slot area and the capacity time slot area for real-time traffic and throughput traffic respectively;

[0012] Step 6, the terminal device performs data reception and transmission in the deterministic time slot area or the capacity time slot area in the corresponding microframe unit according to the time slot resources allocated in step 5;

[0013] Step 7, the access point device collects real-time transmission delay statistics and throughput statistics generated in the data reception and transmission process of the terminal device in step 6;

[0014] Step 8, according to the real-time transmission delay statistics and the throughput statistics collected in step 7, the access point device reallocates the time slot quantity proportion of the deterministic time slot area and the capacity time slot area in the subsequent complete cycle frame.

[0015] Further, the wireless TDMA real-time and throughput hybrid scheduling method based on double-layer time slot separation provided by the application, the step 1 comprises:

[0016] The access point device receives a signaling message sent by the terminal device in an initialization stage or a state change;

[0017] The access point device extracts a terminal device unique identifier, a requested traffic type identifier and a quality of service requirement parameter from the received signaling message;

[0018] The access point device aggregates and maintains a historical transmission performance record of the terminal device based on the extracted terminal device unique identifier, the historical transmission performance record including a time slot usage success rate and a data queue state of the terminal device in a historical period;

[0019] The access point device performs smoothing processing on the aggregated and maintained historical transmission performance record to generate a trend parameter for predicting future resource demand.

[0020] Further, the wireless TDMA real-time and throughput hybrid scheduling method based on double-layer time slot separation according to the present application, step 2 includes:

[0021] The access point device sends a frame synchronization signal at the starting position of each complete cycle frame, the frame synchronization signal carrying an absolute frame sequence number and a macro resource allocation strategy;

[0022] The access point device inserts a microframe synchronization signal at the starting position of each microframe unit defined in step 3, the microframe synchronization signal carrying a microframe index and micro-level time slot allocation information;

[0023] The terminal device receives the microframe synchronization signal, compares the reception time stamp with the local timer value, and calculates a clock offset;

[0024] The terminal device corrects the local timer according to the calculated clock offset, so that the local timing of the terminal device is aligned with the starting boundary of the microframe unit.

[0025] Further, the wireless TDMA real-time and throughput hybrid scheduling method based on double-layer time slot separation according to the present application, step 3 includes:

[0026] The access point device defines the duration of the complete cycle frame as a fixed value, and equally divides the complete cycle frame into a preset number of microframe units;

[0027] The access point device defines a time slot layout for each microframe unit divided, in which the fast access time slot area is located at the starting part, the deterministic time slot area is located at the middle part, and the capacity time slot area is located at the end part;

[0028] The access point device defines the size of the time slot unit included in the deterministic time slot area to be smaller than the size of the time slot unit included in the capacity time slot area.

[0029] Further, the wireless TDMA real-time and throughput hybrid scheduling method based on double-layer time slot separation according to the present application, step 5 includes:

[0030] The access point device counts the number of real-time traffic terminal devices waiting for scheduling and the total amount of throughput traffic data according to the traffic characteristic identifier collected in step 1;

[0031] The access point device calculates the occupancy rate of the deterministic time slot area in the current period, and inquires the queue backlog of the terminal device data queue corresponding to the number of real-time traffic terminal devices;

[0032] When the calculated occupancy rate is greater than the first threshold value and it is inquired that there is queue backlog, the access point device adjusts one time slot unit of the capacity time slot area to the deterministic time slot area from the next period;

[0033] When the calculated occupancy rate is lower than the second threshold value and it is inquired that there is no queue backlog, the access point device adjusts one time slot unit of the deterministic time slot area to the capacity time slot area from the next period;

[0034] The access point device generates scheduling signaling including the updated time slot layout, and broadcasts the scheduling signaling through the frame synchronization signal generated in step 2.

[0035] Further, the wireless TDMA real-time and throughput hybrid scheduling method based on double-layer time slot separation provided by the application comprises the following steps:

[0036] For the terminal device which has been allocated the pre-defined time slot mapping table in step 4, periodic data transmission is carried out in the designated time slot position of the deterministic time slot area;

[0037] For the terminal device which is dynamically allocated to the capacity time slot area resource in step 5, batch data transmission is carried out in the one or more continuously allocated capacity time slot units;

[0038] In the preset management microframe, the access point device reserves part of the resources of the capacity time slot area as a random access window, through which the access point device receives and responds to the network access request and network announcement of the terminal device.

[0039] Further, the wireless TDMA real-time and throughput hybrid scheduling method based on double-layer time slot separation provided by the application comprises the following steps:

[0040] The access point device collects real-time traffic end-to-end transmission delay samples generated in the data transmission process of the terminal device in step 6;

[0041] The access point device calculates the average delay and delay jitter value based on the collected delay samples;

[0042] The access point device measures the effective data transmission amount of the capacity time slot area in unit time as the network throughput;

[0043] The access point device counts the number of idle time slots in the deterministic time slot area without data transmission.

[0044] Further, the wireless TDMA real-time and throughput hybrid scheduling method based on double-layer time slot separation provided by the application further comprises:

[0045] The terminal device receives and parses the microframe synchronization signal generated in step 2 to obtain the micro-slot allocation information carried by the microframe synchronization signal after completing clock synchronization according to the microframe unit starting boundary defined in step 3;

[0046] The terminal device determines the starting time point and the ending time point of the fast access time slot area, the deterministic time slot area, and the capacity time slot area in the subsequent microframe unit according to the parsed micro-slot allocation information;

[0047] For the terminal device allocated with time slot resources in step 5, the physical layer frame timing required for the terminal device to send or receive data is calculated in combination with the time slot unit size defined in step 4 and the determined starting time point and ending time point;

[0048] The terminal device allocated with time slot resources in step 5 associates the calculated transmission timing plan spanning multiple consecutive microframe units with the absolute frame sequence number in the frame synchronization signal according to the macro-resource allocation strategy carried by the frame synchronization signal in step 2, thereby generating a long-term transmission schedule.

[0049] Further, the wireless TDMA real-time and throughput hybrid scheduling method based on double-layer time slot separation according to the present application, the data reception and transmission in the fast access time slot area, the deterministic time slot area, and the capacity time slot area in step 6 includes:

[0050] In the fast access time slot area, the terminal device directly sends at the starting time of the fast access time slot area when an emergency message is detected;

[0051] In the deterministic time slot area, a specific time slot unit is bound to a device identifier of a specific terminal device according to the predefined time slot mapping table generated in step 4 or the dynamic allocation result of step 5, and the terminal device whose device identifier is not bound is prohibited from initiating transmission in the specific time slot unit;

[0052] In the capacity time slot area, one or more capacity time slot units are continuously allocated to a specific terminal device by the scheduling decision of step 5, and the capacity time slot unit allows spanning adjacent microframe units.

[0053] Further, the wireless TDMA real-time and throughput hybrid scheduling method based on double-layer time slot separation according to the present application, adjusting one time slot unit of the capacity time slot area to the deterministic time slot area in step 5 includes:

[0054] The access point device marks one time slot unit of the capacity time slot area before generating the scheduling signaling;

[0055] The access point device sends a resource recovery instruction to the terminal device using one 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 in the current period.

[0056] After the transmission corresponding to one time slot unit of the capacity time slot area ends, the access point device modifies the type identifier to the deterministic time slot area.

[0057] The access point device broadcasts the time slot unit with the modified type identifier as newly added deterministic time slot resources in the frame synchronization signal generated in the next period.

[0058] The adjustment of one time slot unit of the deterministic time slot area to the capacity time slot area in step 5 comprises:

[0059] The access point device identifies one time slot unit of the deterministic time slot area in the current period.

[0060] If the terminal device bound to one time slot unit of the deterministic time slot area has no data transmission in the current period, the access point device directly modifies the type identifier of the time slot unit to the capacity time slot area in the next period.

[0061] If the terminal device bound to one time slot unit of the deterministic time slot area has data transmission in the current period, the access point device migrates the data transmission task of the terminal device to other time slot units in the same deterministic time slot area and then modifies the type identifier of the original time slot unit to the capacity time slot area.

[0062] Advantages of the present application;

[0063] The present application sequentially divides each micro frame unit into a quick access time slot area, a deterministic time slot area and a capacity time slot area through a double-layer time slot separation architecture, realizes physical isolation of real-time traffic and throughput traffic, reduces transmission conflicts and queuing delays, the access point device generates a predefined time slot mapping table based on the collected terminal device traffic characteristic identifier, allocates a fixed transmission position for periodic real-time traffic, avoids scheduling request overhead, realizes zero scheduling delay, the centralized scheduling decision device comprehensively considers device state parameters and dynamically adjusts the time slot proportion of the transmission structure, increases real-time resources when the occupancy rate of the deterministic time slot area is greater than a threshold and the queue backlog is large, optimizes throughput resources when the occupancy rate is lower than the threshold, improves resource utilization, the terminal device performs data transmission and reception in the allocated time slot, the access point device collects transmission delay and throughput statistics and reallocates the proportion of time slots according to the statistical results, balances real-time requirements and throughput efficiency, and overall improves the reliability and performance of the wireless network in the industrial Internet of Things scene. BRIEF DESCRIPTION OF DRAWINGS

[0064] In order to more clearly illustrate the technical solutions of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, for those skilled in the art, other drawings can also be obtained from the drawings without any creative effort.

[0065] Figure 1 The new device access flow diagram provided for the first embodiment of the present application;

[0066] Figure 2 The adaptive adjustment flow diagram when real-time devices are added provided for the second embodiment of the present application;

[0067] Figure 3 The emergency signal processing flow diagram provided for the third embodiment of the present application;

[0068] Figure 4 The device leaving and resource recycling flow diagram provided for the fourth embodiment of the present application. DETAILED DESCRIPTION

[0069] In order to make the technical solutions of the present application clearer, the following will combine the specific embodiments of the present application and the corresponding drawings to clearly and completely describe the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort are within the scope of protection of the present application. The following will combine the drawings to specifically describe the present application provided by the embodiments of the present application. In order to better understand the purpose of the present application, the following will further describe the present application in detail.

[0070] Please refer to Figures 1 to 4 The present application provides a wireless TDMA real-time and throughput mixed scheduling method based on double-layer time slot separation, which comprises:

[0071] Step 1: The access point device collects the device state parameters and traffic characteristic identifiers reported by the terminal device;

[0072] Step 2: Based on the device state parameters and traffic characteristic identifiers collected in step 1, the access point device constructs a hierarchical time reference and periodically generates a frame synchronization signal including an absolute time reference and a microframe synchronization signal including a relative time offset;

[0073] Step 3: Based on the frame synchronization signal and the microframe synchronization signal generated in step 2, the access point device configures a transmission structure including at least one complete cycle frame, each complete cycle frame is divided into a plurality of repeated microframe units, and each microframe unit sequentially arranges a fast access time slot area, a deterministic time slot area and a capacity time slot area;

[0074] 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 identified as periodic, the time slot mapping table including fixed transmission location information bound to the terminal device identifier;

[0075] Step 5, based on the device state parameters and traffic characteristic identifiers collected in step 1 and the transmission structure configured in step 3, the access point device performs centralized scheduling decision, and calculates and allocates time slot resources in the deterministic time slot area and the capacity time slot area for real-time traffic and throughput traffic respectively;

[0076] Step 6, the terminal device performs data transmission and reception in the deterministic time slot area or the capacity time slot area in the corresponding microframe unit according to the time slot resources allocated in step 5;

[0077] Step 7, the access point device collects real-time transmission delay statistics and throughput statistics generated in the data transmission and reception process of the terminal device in step 6;

[0078] Step 8, according to the real-time transmission delay statistics and throughput statistics collected in step 7, the access point device reallocates the proportion of time slots in the deterministic time slot area and the capacity time slot area in the subsequent complete cycle frame.

[0079] When the access point device starts, it collects the signaling messages sent by the terminal device in the initialization stage or when the state changes, extracts the terminal device unique identifier, the requested traffic type identifier and the quality of service demand parameters from the messages. Based on the extracted terminal device unique identifier, the access point device aggregates and maintains the historical transmission performance record of the terminal device, including the time slot usage success rate and the data queue state, and performs smoothing processing on the historical transmission performance record to generate trend parameters for predicting future resource demand. This collection process provides basic data support for subsequent resource scheduling.

[0080] Based on the collected device state parameters and traffic characteristic identifiers, the access point device constructs a hierarchical time reference, sends a frame synchronization signal at the starting position of each complete cycle frame, and the frame synchronization signal carries an absolute frame sequence number and a macro resource allocation strategy. The access point device inserts a microframe synchronization signal at the starting position of each microframe unit, and the microframe synchronization signal carries a microframe index and micro observation time slot allocation information. After receiving the microframe synchronization signal, the terminal device compares the received time stamp with the local timer value, calculates the clock offset, and corrects the local timer according to the clock offset, so that the local time of the terminal device is aligned with the starting boundary of the microframe unit, thereby establishing high-precision time synchronization.

[0081] The access point device configures a transmission structure including at least one full-cycle frame based on the generated frame synchronization signal and the microframe synchronization signal, the full-cycle frame has a fixed duration and is equally divided into a preset number of microframe units. For each microframe unit, the access point device defines a time slot layout, in which the fast access time slot region is located at the starting portion, the deterministic time slot region is located at the middle portion, and the capacity time slot region is located at the end portion. The access point device defines the size of the time slot unit included in the deterministic time slot region to be smaller than the size of the time slot unit included in the capacity time slot region, so as to adapt to the transmission requirements of different traffic types.

[0082] The access point device parses the collected traffic characteristic identifier, generates a predefined time slot mapping table for real-time traffic identified as periodic, and 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 request, realizing transmission efficiency with zero scheduling delay.

[0083] Based on the collected device state parameters and traffic characteristic identifiers and the configured transmission structure, the access point device performs centralized scheduling decision, and counts the number of real-time traffic terminal devices waiting for scheduling and the total amount of throughput traffic data. The access point device calculates the occupancy rate of the deterministic time slot region in the current cycle, and queries the terminal device data queue backlog corresponding to the number of real-time traffic terminal devices. When the occupancy rate is greater than a first threshold value and there is a queue backlog, the access point device adjusts one time slot unit of the capacity time slot region to the deterministic time slot region from the next cycle; when the occupancy rate is lower than a second threshold value and there is no queue backlog, the access point device adjusts one time slot unit of the deterministic time slot region to the capacity time slot region from the next cycle. The access point device generates scheduling signaling including the updated time slot layout, and broadcasts the scheduling signaling through the frame synchronization signal, realizing dynamic resource allocation.

[0084] The terminal device performs data transmission and reception in the deterministic time slot region or the capacity time slot region in the corresponding microframe unit according to the allocated time slot resource. For the terminal device allocated with the predefined time slot mapping table, periodic data transmission and reception is performed at the specified time slot position of the deterministic time slot region; for the terminal device dynamically allocated with the capacity time slot region resource, batch data transmission and reception is performed in one or more continuously allocated capacity time slot units. In the preset management microframe, the access point device reserves part of the resources of the capacity time slot region as a random access window, receives and responds to the network access request and network announcement of the terminal device through the random access window, and supports dynamic management of the device.

[0085] The access point device collects real-time transmission delay statistics and throughput statistics generated in the terminal device data transmission process, including real-time traffic end-to-end transmission delay samples, average delay and delay jitter values, and the effective data transmission amount of the capacity time slot area in unit time as the network throughput. The access point device also statistically determines the number of idle time slots in the deterministic time slot area without data transmission, providing a basis for subsequent adjustment.

[0086] According to the collected real-time transmission delay statistics and throughput statistics, the access point device redistributes the time slot proportion of the deterministic time slot area and the capacity time slot area in the subsequent full cycle frame. This adaptive adjustment process is based on the statistical results of the full cycle frame, gradually modifies the time slot proportion, balances the resource needs of real-time traffic and throughput traffic, and improves the overall network performance.

[0087] In step 1, the access point device receives the signaling message sent by the terminal device actively in the initialization or state change by listening to the wireless channel. The message is packaged in a specific format, including device identity and traffic demand information. The access point device parses the payload part of the signaling message, extracts the terminal device unique identifier, the requested traffic type identifier, and the quality of service demand parameters, the traffic type identifier distinguishes real-time traffic and throughput traffic, and the quality of service demand parameters include delay upper limit and bandwidth requirement. The access point device indexes the internal database based on the terminal device unique identifier, aggregates the historical transmission performance records of the device, and the record content covers the time slot usage success rate and data queue state in the historical period, the time slot usage success rate reflects the transmission reliability, and the data queue state indicates the amount of buffered data. The access point device applies a sliding window algorithm to smooth the historical transmission performance records, filters out short-term fluctuations, generates trend parameters for predicting future resource demand, and provides data support for subsequent scheduling decisions.

[0088] In step 2, the access point device constructs a hierarchical time reference, generates and sends a frame synchronization signal at the starting position of each full cycle frame, and the frame synchronization signal carries an absolute frame sequence number and a macro resource allocation strategy. The access point device inserts a microframe synchronization signal at the starting position of each microframe unit, and the microframe synchronization signal includes a microframe index and micro observation time slot allocation information. The microframe index locates the position of the microframe in the full cycle frame. After receiving the microframe synchronization signal, the terminal device compares the received timestamp with the local timer value, calculates the clock offset, and the clock offset reflects the time difference between devices. The terminal device corrects the local timer using a linear correction algorithm based on the calculated clock offset, aligns the local time of the terminal device with the starting boundary of the microframe unit, realizes high-precision time synchronization, and reduces the transmission timing error.

[0089] Step 3 involves transmission structure configuration. The access point device defines the duration of the complete periodic frame as a fixed value, equally divides the complete periodic frame into a preset number of microframe units, and the microframe units are consistent in period to ensure timing regularity. The access point device defines a time slot layout for each microframe unit, and the fast access time slot area in the time slot layout is located at the starting portion for emergency message transmission, the deterministic time slot area is located at the middle portion and is allocated to real-time traffic, and the capacity time slot area is located at the end portion and serves throughput traffic. The access point device sets the size of the time slot unit included in the deterministic time slot area to be smaller than the size of the time slot unit included in the capacity time slot area, the small-size time slot unit matches the small packet characteristics of real-time traffic, reduces transmission delay, the large-size time slot unit adapts to large data volume transmission of throughput traffic, and improves efficiency.

[0090] Step 5 performs centralized scheduling decision. The access point device identifies the number of real-time traffic terminal devices waiting for scheduling and the total amount of throughput traffic data according to the collected traffic characteristics, the number of real-time traffic terminal devices affects the allocation of the deterministic time slot area, and the total amount of throughput traffic data determines the demand for the capacity time slot area. The access point device calculates the occupancy rate of the deterministic time slot area in the current period, the occupancy rate is calculated based on the time slot usage, and the terminal device data queue backlog corresponding to the number of real-time traffic terminal devices is queried. The queue backlog represents the amount of data to be transmitted. When the occupancy rate is greater than a first threshold value and there is a queue backlog, the access point device adjusts one time slot unit of the capacity time slot area to the deterministic time slot area from the next period, increasing real-time resource allocation. When the occupancy rate is lower than a second threshold value and there is no queue backlog, the access point device adjusts one time slot unit of the deterministic time slot area to the capacity time slot area from the next period, optimizing throughput performance. The access point device generates scheduling signaling including the updated time slot layout, the scheduling signaling encapsulates new time slot allocation information, and broadcasts it to all terminal devices through the frame synchronization signal, realizing dynamic resource adjustment.

[0091] Step 6 involves terminal devices performing data transmission and reception operations according to the time slot resources allocated by the access point device. Terminal devices that have been allocated a predefined time slot mapping table perform periodic data transmission and reception at fixed time slot positions in the deterministic time slot area, which avoids the overhead of scheduling requests and directly uses preconfigured time slots to transmit real-time traffic, such as sensor data reporting in industrial control. Terminal devices dynamically allocated to capacity time slot area resources perform batch data transmission and reception in one or more continuously allocated capacity time slot units, which are larger in size and suitable for transmitting large-capacity data such as logs or images, reducing the number of fragmentation times. In the preset management microframe, the access point device reserves part of the resources of the capacity time slot area as a random access window, which uses a contention mechanism to allow new terminal devices to send network access requests or network departure announcements. The access point device listens to the window and responds to management signaling, supporting dynamic access and departure of network devices.

[0092] The design of step 6 reflects the differentiated use of time slot resources, with a predefined mapping table ensuring the determinacy of real-time traffic, dynamic allocation optimizing the efficiency of throughput traffic, and a random access window handling network topology changes. The operation relies on the time slot mapping table generated in step 4 and the dynamic scheduling results of step 5, ensuring that resource allocation matches traffic characteristics.

[0093] In step 7, the access point device collects performance statistics generated during the data transmission and reception process of the terminal device. Real-time traffic end-to-end transmission delay samples are calculated through timestamp recording, and the access point device calculates the average delay and delay jitter values based on the samples to evaluate the timeliness of real-time traffic. The effective data transmission volume in the capacity time slot area is measured within a unit of time as a network throughput indicator, reflecting the transmission efficiency of bulk traffic. The number of idle time slots in the deterministic time slot area is counted to identify resource waste. Statistics are based on actual transmission data from step 6, providing a basis for resource reallocation in step 8.

[0094] The statistical collection process is integrated into the data transmission cycle, and the access point device automatically aggregates delay and throughput data using the count information carried by the frame synchronization signal. The sliding window algorithm is used to smooth short-term fluctuations when calculating the average delay, and the delay jitter value is obtained through variance analysis. Throughput measurement focuses on the payload, excluding protocol overhead. Idle time slot statistics identify unused deterministic resources, and the indicators collectively characterize the network load state.

[0095] After the terminal device completes clock synchronization at the start boundary of the microframe unit, it receives and parses the microframe synchronization signal, extracting micro time slot allocation information, including time zone boundaries and time slot indexes. After parsing, the terminal device determines the start and end time points of the fast access time slot area, the deterministic time slot area, and the capacity time slot area in the subsequent microframe unit, based on the relative timestamp of the microframe synchronization signal. For terminal devices with allocated time slot resources, the physical layer frame transmission or reception timing, such as frame interval and modulation timing, is calculated based on the time slot unit size and time zone boundaries. The terminal device associates the transmission timing plan spanning multiple microframe units with the absolute frame sequence number based on the macro resource allocation strategy carried by the frame synchronization signal, generates a long-term transmission plan table, and guides multi-cycle data transmission.

[0096] This step enhances the accuracy of time synchronization, with the microframe synchronization signal providing frequent clock calibration to avoid drift accumulation. Timing calculation ensures that devices activate the transceiver circuit at the correct time, reducing conflicts. The long-term plan table supports continuous transmission across frames, improving throughput efficiency, and cooperates with the scheduling decisions of step 5 to achieve resource reservation and timing alignment.

[0097] In the fast access time slot area, when the terminal device detects an emergency message such as a safety alarm, it directly transmits at the start time of the time slot without waiting for authorization, thereby ensuring a low-delay response. In the deterministic time slot area, according to a predefined time slot mapping table or a dynamic allocation result, a specific time slot unit is bound to a terminal device identifier, and after the binding, other devices are prohibited from transmitting in the time slot unit, thereby forming a dedicated channel. In the capacity time slot area, a scheduling decision allocates a group of continuous time slot units to the terminal device, and the units can span adjacent microframe units, thereby forming a large transmission window and reducing switching overhead.

[0098] Such a design distinguishes traffic priorities, processes sudden emergencies in the fast access time slot, guarantees the isolation of real-time traffic in the deterministic time slot, and optimizes batch transmission in the capacity time slot. The binding mechanism prevents interference, and the continuous allocation improves throughput performance. The design is consistent with the time slot layout in step 3 and meets the mixed needs of industrial scenarios.

[0099] When one time slot unit of the capacity time slot area is adjusted to the deterministic time slot area, the access point device first marks the one time slot unit of the capacity time slot area, sends a resource recovery instruction to a terminal device using the one time slot unit of the capacity time slot area through microframe synchronization signal-carrying micro time slot allocation information, and specifies a migration time point. After the end of the transmission corresponding to the unit, the access point device modifies the type identifier to the deterministic time slot area, and broadcasts an authorization in the next period frame synchronization signal to make the new resource effective. When one time slot unit of the deterministic time slot area is adjusted to the capacity time slot area, the access point device identifies the one time slot unit of the deterministic time slot area. If the one time slot unit of the deterministic time slot area is not bound to a device with data transmission, the type identifier is directly modified. If there is data transmission, the task is migrated to other time slot units in the same area before the identifier is modified, and the migration process guarantees data continuity.

[0100] The adjustment process is based on the statistical feedback of step 7 to dynamically optimize the resource proportion. The resource recovery instruction avoids transmission interruption, and the migration mechanism guarantees lossless service. The broadcast authorization notifies all devices of the change, thereby maintaining the consistency of the network state. Such a gradual adjustment balances the real-time and throughput needs, thereby improving the resource utilization rate.

[0101] In the industrial Internet of Things scenario, a wireless network needs to support real-time control traffic and batch data traffic at the same time. However, the existing technology adopts a single time slot granularity design, which leads to low resource utilization rate of real-time small packet traffic and poor transmission efficiency of batch large packet traffic. A random delay is introduced by a contention-based random access mechanism, which affects the deterministic response. The present application provides a wireless TDMA hybrid scheduling method based on double-layer time slot separation, which solves the above problems through time slot resource isolation and dynamic allocation.

[0102] After the access point device starts, first, the device state parameters and traffic characteristic identifiers reported by the terminal device are collected. In the intelligent factory environment, the terminal devices such as PLC controllers and sensors send signaling messages in the initialization stage, and the access point parses the messages to extract the device unique identifier, traffic type identifier and quality of service requirement parameter. The access point maintains historical transmission performance records, including time slot usage success rate and data queue state, and generates trend parameters for predicting resource requirements through smoothing processing.

[0103] Based on the collected data, the access point constructs a hierarchical time reference, generates a frame synchronization signal and a microframe synchronization signal. The frame synchronization signal carries an absolute frame sequence number and a macro resource strategy, and the microframe synchronization signal provides a microframe index and micro time slot allocation information. After receiving the synchronization signal, the terminal device calibrates the local clock and aligns with the starting boundary of the microframe unit, realizing high-precision time synchronization.

[0104] The access point configures a transmission structure, divides a complete cycle frame into multiple microframe units, and sequentially arranges a fast access time slot area, a deterministic time slot area and a capacity time slot area in each microframe unit. The fast access time slot area is located at the starting part and is used for emergency messages; the deterministic time slot area is in the middle and is allocated to real-time traffic; and the capacity time slot area is at the end and serves the throughput traffic. The size of the time slot unit in the deterministic time slot area is smaller than that in the capacity time slot area, matching different traffic characteristics.

[0105] A pre-defined time slot mapping table is generated for periodic real-time traffic, binding the device identifier with the fixed transmission position. In the device association stage, the access point parses the traffic identifier, allocates the fixed time slot position, and the terminal device automatically sends data at the predetermined time without the need for a scheduling request, realizing zero scheduling delay. For example, the periodic heartbeat packet of the PLC controller is directly transmitted in the specified time slot, avoiding the competition overhead.

[0106] The access point performs centralized scheduling decision, counts the number of real-time devices and the total amount of throughput data, calculates the deterministic time slot area occupancy rate and queries the queue backlog. When the occupancy rate is greater than the threshold and there is backlog, one time slot unit in the capacity time slot area is adjusted to the deterministic time slot area; when the occupancy rate is lower than the threshold and there is no backlog, the reverse adjustment is made. The scheduling signaling is broadcast through the frame synchronization signal, realizing dynamic resource allocation. In the production line expansion scenario, the addition of real-time devices triggers adaptive adjustment, gradually optimizing the time slot proportion, and avoiding system oscillation.

[0107] The terminal device transmits and receives data in the corresponding time slot area according to the allocated resources. The devices with pre-configured mapping tables perform periodic transmission in the deterministic time slot area, and the dynamically allocated devices perform batch transmission in the capacity time slot area. In the management microframe, the access point reserves a random access window to handle the network access request and network announcement, supporting dynamic management of devices.

[0108] The access point collects transmission delay samples and throughput statistics, calculates average delay, delay jitter value and network throughput, and counts the number of idle time slots. Based on the statistical results, the access point re-allocates the time slot proportion of the subsequent full cycle frame, balances the real-time and throughput requirements. For example, when the real-time time slot is idle, the resource elasticity is lent to the throughput time slot for use, improving the utilization rate.

[0109] In the security monitoring scene, when the terminal device detects an emergency message, it is directly transmitted at the starting time of the fast access time slot area without authorization, ensuring low delay response. The access point quickly broadcasts the response after receiving the signal, and the processing delay is significantly reduced. This process reflects the priority design of the fast access time slot area. The emergency signal processing flow is as shown in Figure 3 The figure shows the direct transmission mechanism of the terminal device in the fast access time slot area.

[0110] When the device leaves the network, the access point receives the off-network announcement through the random access window, identifies the time slot unit to be released. If there is no data transmission, the type identifier is directly modified; if there is data, the task is migrated and adjusted. The resource recycling process combines statistical monitoring to gradually adjust the time slot proportion and improve overall efficiency. For example, after some real-time devices are disconnected, the idle time slots are re-allocated to the throughput traffic to digest the queue backlog.

[0111] The present application realizes the deterministic delay of real-time traffic and the high efficiency of throughput traffic in the industrial Internet of Things scene through double-layer time slot separation, pre-configuration authorization and dynamic scheduling, and solves the technical problems caused by single time slot granularity and competition mechanism.

[0112] Embodiment one, please refer to the attached Figure 1In the smart factory scenario of the industrial Internet of Things, the access point device performs step 1 after starting, the access point collects the signaling messages reported by terminal devices such as PLC controllers and sensors during initialization by listening to the channel, extracts the device unique identifier, traffic type identifier (such as real-time control instruction or batch data) and quality of service parameter, and maintains historical transmission records, including time slot usage success rate and data queue state, and generates trend parameters through a sliding window algorithm. Step 2, the access point constructs a hierarchical time reference, sends a frame synchronization signal at the start of each 10ms complete frame, carries an absolute frame number and macro resource strategy, and inserts a microframe synchronization signal at the start of each 1ms microframe unit. After receiving the terminal device, the clock offset is calculated, and the local timer is corrected to realize synchronization. Step 3, the access point configures the transmission structure, divides the complete frame into 10 microframe units, and each microframe uses a unified layout: fast access time slot area (fixed 110us), deterministic time slot area (configurable 220-660us) and capacity time slot area (remaining time slots), wherein the size of the deterministic time slot unit is smaller than that of the capacity time slot unit. Step 4, the access point analyzes the traffic identifier, generates a predefined time slot mapping table for periodic real-time traffic, binds the device ID with the fixed time slot position, and for example, allocates a specific microframe deterministic time slot area for PLC heartbeat packet. Step 5, the access point performs centralized scheduling, counts the number of real-time devices and the total amount of throughput data, calculates the deterministic time slot area occupancy rate, and when it is greater than the 80% threshold and the queue is accumulated, one time slot unit in the capacity time slot area is adjusted to the deterministic time slot area from the next period, and the updated scheduling signaling is broadcast through the frame synchronization signal. Step 6, the terminal device transmits and receives data according to the allocated resources, such as real-time devices sending in predefined time slots, throughput devices transmitting in continuous capacity time slot units, and managing the reserved random access window in the microframe to handle network access requests. Step 7, the access point collects real-time transmission delay samples and throughput statistics, calculates the average delay and the number of idle time slots. Step 8, based on the statistical results, adjust the time slot proportion, for example, reduce the idle deterministic time slot to increase the capacity resource.

[0113] Embodiment two, please refer to the attached Figure 2, for the industrial production line expansion scenario, the initial network has 3 PLC controllers and 10 data collectors, configured as deterministic time slot zone 2 units (220us) and capacity time slot zone 6 units (660us), each PLC obtains about 73us time slot. After the event trigger, 5 new PLCs are accessed, the real-time device increases to 8, the access point detects that the deterministic time slot zone occupancy rate rises from 70% to 95% and the queue backlog is 3 packets, which meets the threshold condition (occupancy rate exceeds 80% and backlog). The access point calculates the current complete frame statistics, broadcasts the adjustment instruction in the Beacon of the microframe 0, increases the deterministic time slot zone to 3 units (330us), and reduces the capacity time slot zone to 5 units (550us), and the adjustment amplitude is gradual ±1 unit, avoiding oscillation. After receiving the signaling, the terminal device re-aligns the time slot, and each PLC obtains about 41us resource, which meets the real-time demand; at the same time, the throughput device adapts to the compressed time slot, and maintains the throughput efficiency. The adjustment process is based on the collected data, such as real-time utilization and queue length, and is associated with the long-term transmission plan through the frame synchronization signal, which embodies the support of dynamic resource reallocation to the flexibility of industrial network, and solves the technical problem that fixed allocation cannot adapt to traffic changes.

[0114] Example three, please refer to the attached Figure 3 In the safety monitoring scenario, the PLC controller detects that the mechanical arm needs to send an emergency stop signal, and the terminal device immediately sends alarm data at the starting time of the current microframe fast access time slot zone (fixed 110us) without pre-configured authorization. After receiving the signal, the access point broadcasts the response in the next available time slot, and the processing delay is less than 1ms. This process relies on the time slot design, the fast access time slot zone has the highest priority, and the unbound device is prohibited from occupying; the access point manages the time slot binding through the microframe synchronization signal to ensure the isolated transmission of emergency traffic. At the same time, the pre-defined time slot mapping table is used for periodic traffic such as PLC regular data, while burst traffic is handled through the fast response mechanism, and the terminal device determines the time zone boundary according to the parsed micro time slot allocation information and calculates the physical layer frame timing.

[0115] Example four, please refer to the attached Figure 4When there are 5 PLC controllers disconnected in the industrial network, the random access window reserved in the capacity time slot area of the microframe 0 by the access point receives the off-network announcement, identifies one time slot unit of the deterministic time slot area. If the binding 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 other time slots in the same area and then the identification is modified. For example, the initial real-time time slot area 5 units (550 μs) utilization rate is reduced to 40%, the access point calculates the trend at the end of the complete frame based on the collected idle time slot statistics, gradually adjusts the deterministic time slot area to 3 units (330 μs), and increases the capacity time slot area to 5 units (550 μs), so that the remaining 3 PLCs each obtain 110 μs of resources. The terminal device updates the long-term transmission schedule according to the Beacon notification, and the throughput device digests the queue backlog by using the newly added capacity time slot.

Claims

1. A wireless TDMA real-time and throughput hybrid scheduling method based on double-layer time slot separation, characterized in that, Comprising: Step 1, the access point device collects the device state parameters and traffic characteristic identifiers reported by the terminal device; Step 2, based on the device state parameters and traffic characteristic identifiers collected in step 1, the access point device constructs a hierarchical time reference and periodically generates a frame synchronization signal including an absolute time reference and a microframe synchronization signal including a relative time offset; Step 3, based on the frame synchronization signal and microframe synchronization signal generated in step 2, the access point device configures a transmission structure including at least one complete cycle frame, each complete cycle frame is divided into a plurality of repeated microframe units, and each microframe unit sequentially arranges a fast access time slot area, a deterministic time slot area and a capacity time slot area; Step 4, the access point device analyzes the traffic characteristic identifiers collected in step 1, generates a predefined time slot mapping table for periodic real-time traffic, and the time slot mapping table includes fixed transmission location information bound to the terminal device identifier; Step 5, based on the device state parameters and traffic characteristic identifiers collected in step 1 and the transmission structure configured in step 3, the access point device performs centralized scheduling decision, calculates and allocates time slot resources in the deterministic time slot area and the capacity time slot area for real-time traffic and throughput traffic respectively; the access point device counts the number of real-time traffic terminal devices waiting for scheduling and the total amount of throughput traffic data according to the traffic characteristic identifiers collected in step 1; the access point device calculates the occupancy rate of the deterministic time slot area in the current cycle, and queries the queue backlog situation of the terminal device data queue corresponding to the number of real-time traffic terminal devices; when the calculated occupancy rate is greater than a first threshold value and the queue backlog is found, the access point device adjusts one time slot unit of the capacity time slot area to the deterministic time slot area from the next cycle; when the calculated occupancy rate is less than a second threshold value and no queue backlog is found, the access point device adjusts one time slot unit of the deterministic time slot area to the capacity time slot area from the next cycle; the access point device generates scheduling signaling including the updated time slot layout, and broadcasts the scheduling signaling through the frame synchronization signal generated in step 2; Step 6, the terminal device performs data transmission and reception in the deterministic time slot area or the capacity time slot area in the corresponding microframe unit according to the time slot resources allocated in step 5; in the fast access time slot area, the terminal device directly sends when detecting an emergency message at the starting time of the fast access time slot area; in the deterministic time slot area, the specific time slot unit is bound to the device identifier of the specific terminal device according to the predefined time slot mapping table generated in step 4 or the dynamic allocation result of step 5, and the terminal device whose device identifier is not bound is prohibited from initiating transmission in the specific time slot unit; in the capacity time slot area, a group of continuous time slot units are allocated to the specific terminal device by the scheduling decision in step 5, and the continuous time slot units allow to span adjacent microframe units; Step 7, the access point device collects real-time transmission delay statistics and throughput statistics generated in the data transmission and reception process of the terminal device in step 6; Step 8, according to the real-time transmission delay statistics and throughput statistics collected in step 7, the access point device re-allocates the time slot proportion of the deterministic time slot area and the capacity time slot area in the subsequent full cycle frame.

2. The wireless TDMA real-time and throughput hybrid scheduling method based on double-layer time-slot separation according to claim 1, characterized in that, The step 1 includes: The access point device receives the signaling message sent by the terminal device in the initialization stage or state change; The access point device extracts the terminal device unique identifier, the requested traffic type identifier and the quality of service demand parameter from the received signaling message; The access point device aggregates and maintains the historical transmission performance record of the terminal device based on the extracted terminal device unique identifier, and the historical transmission performance record includes the time slot usage success rate and the data queue state of the terminal device in the historical cycle; The access point device performs smoothing processing on the aggregated and maintained historical transmission performance record to generate trend parameters for predicting future resource demand.

3. The wireless TDMA real-time and throughput hybrid scheduling method based on double-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 starting position of each full cycle frame, and the frame synchronization signal carries an absolute frame sequence number and a macro resource allocation strategy; The access point device inserts a microframe synchronization signal at the starting position of each microframe unit defined in step 3, and the microframe synchronization signal carries a microframe index and microslot allocation information; The terminal device receives the microframe synchronization signal, compares the received time stamp with the local timer value, and calculates the clock offset; The terminal device corrects the local timer according to the calculated clock offset to align the terminal device local timing with the starting boundary of the microframe unit.

4. The wireless TDMA real-time and throughput hybrid scheduling method based on double-layer time-slot separation according to claim 3, characterized in that, Step 3 includes: The access point device defines the duration of the full cycle frame as a fixed value, and equally divides the full cycle frame into a preset number of microframe units; The access point device defines a time slot layout for each microframe unit, in which the fast access time slot area is located at the starting part, the deterministic time slot area is located at the middle part, and the capacity time slot area is located at 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 double-layer time-slot separation according to claim 4, characterized in that, The step 6 includes: For the terminal device that has allocated a predefined time slot mapping table in step 4, periodic data transmission is performed at the specified time slot position of the deterministic time slot area; For the terminal device that is dynamically allocated to the capacity time slot area resource in step 5, batch data transmission is performed in one or more continuously allocated capacity time slot units; In the preset management microframe, the access point device reserves part of the resources of the capacity time slot area as a random access window, through which the access point device receives and responds to the network access request and off-network announcement of the terminal device.

6. The wireless TDMA real-time and throughput hybrid scheduling method based on double-layer time-slot separation according to claim 5, characterized in that, Step 7 includes: The access point device collects real-time traffic end-to-end transmission delay samples generated in the terminal device data transmission process in step 6; The access point device calculates the average delay and delay jitter value based on the collected delay samples; The access point device measures the effective data transmission amount of the capacity time slot area in unit time as the network throughput; The access point device counts the number of idle time slots in the deterministic time slot area without data transmission.

7. The wireless TDMA real-time and throughput hybrid scheduling method based on double-layer time-slot separation according to claim 6, characterized in that, Also includes: The terminal device receives and parses the microframe synchronization signal generated in step 2 to obtain the micro-slot allocation information carried by the microframe synchronization signal after completing clock synchronization according to the microframe unit start boundary defined in step 3; The terminal device determines the start time point and the end time point of the fast access time slot area, the deterministic time slot area and the capacity time slot area in the subsequent microframe unit according to the parsed micro-slot allocation information; For the terminal device allocated with the time slot resource in step 5, the physical layer frame timing required for the terminal device to send or receive data is calculated in combination with the time slot unit size defined in step 4 and the determined start time point and end time point; The terminal device allocated with the time slot resource in step 5 associates the calculated transmission timing plan spanning multiple continuous microframe units with the absolute frame sequence number in the frame synchronization signal according to the macro-resource allocation strategy carried by the frame synchronization signal in step 2, thereby generating a long-term transmission plan table.

8. The wireless TDMA real-time and throughput hybrid scheduling method based on double-layer time-slot separation according to claim 7, characterized in that, The adjustment of one time slot unit of the capacity time slot area to the deterministic time slot area in step 5 includes: The access point device marks the capacity time slot unit to be adjusted before generating the scheduling signaling; The access point device sends a resource recovery instruction to the terminal device using the capacity time slot unit to be adjusted through the micro-slot allocation information carried by the microframe synchronization signal generated in step 2 in the current period; After the transmission corresponding to the capacity time slot unit to be adjusted ends, the access point device modifies the type identifier thereof to the deterministic time slot area; The access point device broadcasts the time slot unit with the modified type identifier as newly added deterministic time slot resource in the frame synchronization signal generated in the next period; The adjustment of one time slot unit of the deterministic time slot area to the capacity time slot area in step 5 includes: The access point device identifies the deterministic time slot unit to be released in the current period; If the terminal device bound to the deterministic time slot unit to be released has no data transmission in the current period, the access point device directly modifies the type identifier thereof to the capacity time slot area in the next period; If the terminal device bound to the deterministic time slot unit to be released has data transmission in the current period, the access point device migrates the data transmission task of the terminal device to other time slot units in the same deterministic time slot area and then modifies the type identifier of the original time slot unit to the capacity time slot area.

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