Enhanced star wireless sensor network system for real-time monitoring

Abstract

The application discloses a real-time monitoring-oriented enhanced star-type wireless sensor network system and belongs to the technical field of wireless sensor networks. In view of the limitations of a traditional star-type topology in transmission distance, network capacity and anti-interference performance, the application introduces a wireless sensor data aggregation node on the basis of an original real-time star-type network architecture composed of a wireless sensor network coordinator node and a wireless sensor parameter acquisition node, and constructs an improved star-type networking scheme which is efficient and expandable. The aggregation node is responsible for receiving, fusing and forwarding sensing data from multiple parameter acquisition nodes in an uplink according to a preset communication protocol, and is responsible for realizing reliable relay and distribution of control instructions issued by the network coordinator node in a downlink. By introducing a hierarchical data processing mechanism, the data transmission efficiency is remarkably improved, the network coverage range is effectively prolonged, and the overall anti-interference capacity of the system is enhanced.

Description

Technical Field

[0001] This invention relates to an enhanced star-shaped wireless sensor network system for real-time monitoring, belonging to the field of wireless sensor technology. Background Technology

[0002] Applying wireless sensor networks to environmental parameter monitoring in complex engineering environments such as aerospace launch vehicles can effectively avoid the complex cable routing problems of traditional wired telemetry and control systems, significantly reduce structural weight, and improve the system's lightweight level. At the same time, this technology provides high flexibility in the layout of measurement points, enabling rapid response to the dynamic addition, deletion, and reconfiguration needs of the number and location of measurement points during the development phase, meeting the requirements of high-density, multi-parameter, and highly adaptable testing tasks.

[0003] Given the stringent requirements of low latency and high real-time performance for environmental monitoring systems imposed by space launch vehicles, typical wireless sensor networks generally adopt a star topology, combined with a time-division multiplexing (TDMA) networking model, and rely on a strict global clock synchronization mechanism to achieve distributed high-frequency acquisition and centralized fusion processing of various parameters such as heat flow, pressure, temperature, vibration, shock, and noise, ensuring the timeliness of data acquisition and the reliability of system operation.

[0004] However, multiple challenges remain in practical applications: On the one hand, the sampling frequencies of various sensor nodes differ significantly, resulting in uneven data generation rates per unit time. If traditional fixed time slot allocation strategies or static network topologies are used, it is easy for some nodes to experience bandwidth congestion while other nodes remain idle, leading to a decrease in overall network transmission efficiency. On the other hand, the confined space and complex electromagnetic environment inside the launch vehicle cabin, along with factors such as metal bulkheads and the installation locations of precision instruments and equipment, create severe obstruction effects. This causes wireless signals to experience non-line-of-sight propagation, multipath fading, and channel mismatch, which in turn leads to increased signal attenuation and higher bit error rates, severely affecting the stability and continuity of data transmission.

[0005] If the data from the wireless sensor parameter acquisition nodes cannot be reliably transmitted to the wireless sensor network coordinator node (master node), the status monitoring center will be unable to detect abnormal operating conditions in a timely manner, and the sensor network will be unable to perform its intended function. This invention proposes an optimization method for wireless sensor networks in complex environments, integrating data aggregation, relay forwarding, and multi-path transmission mechanisms to improve the real-time performance, robustness, and reliability of wireless sensor networks under complex operating conditions. Summary of the Invention

[0006] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide an enhanced star-shaped wireless sensor network system for real-time monitoring. For sensor networks using a star topology, a wireless sensor aggregation node is added, and data aggregation, relay forwarding, and multi-path transmission mechanisms are integrated to improve the transmission efficiency, coverage, and fault tolerance of the wireless sensor network while ensuring low latency.

[0007] The technical solution of this invention is: An enhanced star-shaped wireless sensor network system for real-time monitoring includes a network coordinator node, several parameter acquisition nodes, and at least one data aggregation node. The network coordinator node and the data aggregation node, the parameter acquisition node, and the data aggregation node and the parameter acquisition node are all wirelessly connected using a star topology, forming a wireless sensor-enhanced star network architecture with the data aggregation node as the cluster head. The network coordinator node is used for the control of the entire sensor network system, including time slot allocation, clock synchronization, sleep / wake-up, and network entry / exit of data aggregation nodes and parameter acquisition nodes; the network coordinator node controls the parameter acquisition nodes and data aggregation nodes by sending command parameters. The parameter acquisition node operates under the command parameters sent by the network coordinator node, collects target physical quantity information in real time, and sends the raw measurement signal to the data aggregation node or network coordinator node through a wireless link after local preprocessing. After receiving data from multiple parameter acquisition nodes, the data aggregation node integrates and compresses the data according to a preset fusion algorithm, and forwards the integrated real-time sensor data to the network coordinator node in a predetermined sequence. At the same time, the data aggregation node also forwards the command parameters sent by the network coordinator node to the parameter acquisition nodes. The network coordinator node performs format standardization processing on the received integrated real-time sensor data and the locally preprocessed raw measurement signals sent by the parameter acquisition nodes to generate data frames that conform to the interface protocol of the backend status monitoring center, and uploads them to the backend status monitoring center in real time.

[0008] Furthermore, the parameter acquisition node is configured with a wireless high-frequency sampling rate sensor, a wireless low-frequency sampling rate sensor, and a wireless slowly varying sampling rate sensor to adapt to the measured signal with different dynamic characteristics.

[0009] Furthermore, the communication between the data aggregation node, the network coordinator node, and the parameter acquisition node follows a preset frame structure and transmission protocol. The preset frame structure includes N periodic network transmission time slots, each of which is subdivided into L secondary time slots according to the actual service load, and the length of each secondary time slot is [missing information]. Furthermore, all network coordinator nodes, parameter acquisition nodes, and data aggregation nodes strictly synchronize their data transmission and reception operations under a global time base.

[0010] Furthermore, the network transmission time slots are specifically divided into the following four types of functional time slots: Node synchronization time slots are used to achieve time and state synchronization among all nodes in a wireless sensor network system. Node parameter time slots are used to transmit node configuration parameters and status information; Node service time slots are used to carry real-time sensor data transmission under normal operating conditions; Node retransmission slots are used to implement reliable retransmission in the event of data loss or bit errors. Each node sends or receives wireless sensor data packets in an orderly manner according to the preset transmission protocol within the corresponding time slot, ensuring the determinism of the data stream and the controllability of the timing.

[0011] Furthermore, the wireless sensor data packets include the following nine categories: Node clock synchronization data packets are used to achieve network-wide time base alignment; The node entry identification data packet is used to uniquely identify the identity information of a registered node; The node network access request data packet is initiated by the newly joining node to request network access. The node access response data packet is returned by the network coordinator node or the aggregation node to confirm access eligibility and resource allocation; The node command parameter data packet is used to issue control commands and parameter configuration commands; Node status parameter data packets are used to report the node's own working status and health indicators; Node status synchronization data packets are used to periodically broadcast the current status of nodes; The node service transmits data packets, carrying real sensor data, with minimal latency; Node service retransmission data packets are used to trigger reliable retransmission when packet loss or errors are detected; All types of data packets are encapsulated based on the preset frame structure and sent sequentially within the specified time slots. Specifically, node clock synchronization data packets are sent within the node synchronization time slot; node network entry identifier data packets, node network entry request data packets, node network entry response data packets, node command parameter data packets, node status parameter data packets, and node status synchronization data packets are sent within the node parameter time slot; node service transmission data packets are sent within the node service time slot; and node service retransmission data packets are sent within the node retransmission time slot.

[0012] Furthermore, in the preset transmission protocol, except for node service transmission data packets and node service retransmission data packets, the length of all other types of data packets is a fixed value, and all nine types of data packets are defined with a unique header field, check field, and payload structure.

[0013] Furthermore, after receiving data from multiple parameter acquisition nodes, the data aggregation node performs data integration and compression processing according to a preset fusion algorithm, and forwards the integrated real-time sensor data to the network coordinator node in a predetermined time sequence, specifically as follows: For data in multi-source heterogeneous wireless sensor networks, common fields in data frames from multiple parameter acquisition nodes are identified and merged to eliminate cross-node information redundancy. Based on the different sampling frequencies of each parameter acquisition node, a time synchronization and hierarchical scheduling mechanism is adopted to reorganize and package the service data of high, medium and low sampling rate parameter acquisition nodes, so that data fields are aligned and dynamically aggregated to form structured transmission units, thereby improving the data carrying density of a single wireless transmission.

[0014] Furthermore, in a wireless sensor network system, the network coordinator node is the master node of the entire network system, and the data aggregation nodes or parameter acquisition nodes under the network coordinator node are slave nodes; in a local network centered on the data aggregation node, the data aggregation node is the master node, and the parameter acquisition nodes are slave nodes.

[0015] Furthermore, in a local network centered on a data aggregation node, the specific usage steps for the data aggregation node and the parameter acquisition nodes under the aggregation node are as follows: (1) The parameter acquisition node joins the local network with the data aggregation node as the master node. The initial configuration is first completed with the assistance of the network coordinator node. The specific process is as follows: (1.1) The network coordinator node powers on and starts working according to the set frame, subframe and time slot lengths, and sends out default node clock synchronization data packets in fixed time slots; (1.2) After receiving the clock synchronization data packet from the default node, the data aggregation node and the parameter acquisition node apply to join the control network with the network coordinator node as the master node; (1.3) The network coordinator node sends a node entry identification data packet, and the data aggregation node and parameter acquisition node return a node entry request data packet containing the node's physical address and the amount of data transmitted by the node; (1.4) The network coordinator node calculates the local network operating parameters, including the length and number of secondary time slots, based on the received node network access request data packets, combined with the wireless sensor network data transmission rate, frame length, and the number of parameter acquisition nodes. (1.5) The network coordinator node sends node clock synchronization data packets for configuring clock synchronization and node command parameter data packets for configuring time slot allocation to the data aggregation node and the parameter acquisition node under the data aggregation node, respectively, and allocates configuration parameters, including node clock synchronization words, secondary time slot length and number; (1.6) The data aggregation node and the parameter acquisition node under the data aggregation node receive the configuration parameters and return the node status parameter data packet of the configuration clock status and time slot status. The network coordinator node confirms whether the configuration is successful. (1.7) Data aggregation nodes and parameter acquisition nodes save local network status information and exit the wireless sensor network with the network coordinator node as the master node; (2) After the parameter acquisition node joins the local network with the data aggregation node as the master node and completes the initial configuration, it receives the node clock synchronization data sent by the data aggregation node during the wake-up cycle, joins the local network, and starts working. The specific process is as follows: (2.1) The network coordinator node powers on and sends wireless sensor network node clock synchronization data packets in a fixed time slot according to the preset frame structure; (2.2) When the data aggregation node receives the node clock synchronization data packet sent by the network coordinator node, it requests to join the wireless sensor network with the network coordinator node as the master node within the time slot of the wireless sensor network. (2.3) After the data aggregation node joins the wireless sensor network, it starts sending node clock synchronization data packets and node network entry identification data packets in the time slots of the wireless sensor network according to the secondary time slots configured during the initialization of the network coordinator node. (2.4) After receiving the secondary clock synchronization data packet during the wake-up cycle, the parameter acquisition node requests to join the local network with the data aggregation node as the master node; (2.5) After receiving the request for network access data from the parameter acquisition node, the data aggregation node determines whether to allow network access based on the current local network information, and returns a network access response data packet in the next time slot of the wireless sensor network; (2.6) The parameter acquisition node receives the network access response data packet of the node that is allowed to enter the network within the second time slot of the local network, and sends the node service data within the service time slot; (2.7) The data aggregation node receives the service data from the parameter acquisition node, summarizes and integrates the node service data according to a fixed format, and sends out the node service integration data packet in the time slot of the wireless sensor network. (2.8) The network coordinator node receives the node service integration data packet, splits the node service integration data packet, and collects and stores the node physical address according to the corresponding parameters; (3) The data aggregation node and the parameter acquisition node under the data aggregation node have completed the network access. The parameter data and service data between the network coordinator node and the parameter acquisition node under the data aggregation node are transmitted through the data aggregation node. (4) When the data aggregation node goes into hibernation and leaves the network, the local network is disbanded; when the parameter acquisition node under the data aggregation node goes into hibernation and leaves the network, the network coordinator node and the data aggregation node still retain the physical address of the parameter acquisition node under the data aggregation node, and it does not need to be re-completed through the network coordinator node to rejoin the wireless sensor network.

[0016] The advantages of this invention compared to the prior art are: (1) The enhanced star-shaped wireless sensor network topology of the present invention can flexibly add measurement nodes for wireless sensors with different sampling rates such as heat flow, pressure, temperature, vibration, and noise. By summarizing and integrating the data transmitted by sensor nodes with different sampling frequencies, the transmission efficiency of the wireless sensor network is optimized. (2) By rationally deploying wireless sensor data aggregation nodes, the present invention achieves efficient relay and forwarding of data from multiple sensor acquisition nodes, expands the communication coverage of the wireless sensor network, and improves the data transmission distance and network scalability.

[0017] (3) In view of the problem that radio signals are susceptible to path loss and physical obstruction in complex environments, this invention proposes a networking scheme based on real-time data aggregation nodes. By using a relay forwarding mechanism, the risk of link interruption is reduced, thereby significantly improving the transmission reliability and coverage of real-time wireless sensor networks.

[0018] (4) The present invention adds a data aggregation node to the wireless sensor network to form a distributed data relay structure, which supports multi-path parallel transmission and backup of key monitoring data, effectively resists the risk of single point of failure, and greatly improves the stability of the overall network operation and the reliability of data transmission. Attached Figure Description

[0019] Figure 1 A schematic diagram of a network system for adding wireless sensor data aggregation nodes.

[0020] Figure 2 A schematic diagram of the network topology for adding wireless sensor data aggregation nodes.

[0021] Figure 3 This is a schematic diagram of the time slot structure for transmitting wireless sensor data aggregation nodes.

[0022] Figure 4 This is a schematic diagram illustrating the connection of a wireless sensor network measurement system.

[0023] Figure 5This is a schematic diagram illustrating the transmission time slot allocation for an example wireless sensor network measurement system. Detailed Implementation

[0024] To better understand the above technical solutions, the technical solutions of this application will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of this application and the specific features in the embodiments are detailed descriptions of the technical solutions of this application, rather than limitations on the technical solutions of this application. In the absence of conflict, the embodiments of this application and the technical features in the embodiments can be combined with each other.

[0025] To address the limitations of traditional star topologies in terms of transmission distance, network capacity, and anti-interference performance, this invention innovatively introduces a wireless sensor data aggregation node into the existing real-time star network architecture, which consists of a wireless sensor network coordinator node and wireless sensor parameter acquisition nodes. This constructs an efficient and scalable improved star networking scheme. This aggregation node, based on a preset communication protocol, is responsible for receiving, fusing, and forwarding sensor data from multiple parameter acquisition nodes in the uplink; and in the downlink, it reliably relays and distributes control commands to the network coordinator node. By introducing a hierarchical data processing mechanism, data transmission efficiency is significantly improved, network coverage is effectively extended, and the overall anti-interference capability of the system is enhanced. This invention is particularly suitable for high-precision, real-time wireless monitoring of mechanical and thermal sensor parameters in aerospace telemetry systems, and is also widely applicable to distributed wireless real-time measurement scenarios in fields such as industrial automation and environmental monitoring.

[0026] The following description, in conjunction with the accompanying drawings, provides a more detailed account of an enhanced star-shaped wireless sensor network system for real-time monitoring provided in this application. Figures 1-5 As shown, the enhanced star-shaped wireless sensor network system for real-time monitoring proposed in this invention adds a wireless sensor data aggregation node to the traditional wireless sensor network coordinator node and wireless sensor parameter acquisition node. By further dividing the wireless sensor network transmission time slots and configuring corresponding clock synchronization words, a local wireless sensor network is established to receive, integrate, and forward measurement data from low-frequency or slowly varying sampling frequency wireless sensor acquisition nodes in the network, thereby improving the transmission efficiency and reliability of the wireless sensor network.

[0027] like Figure 1 As shown, in the solution provided in the embodiments of this application, the enhanced star-shaped wireless sensor network system for real-time monitoring includes a network coordinator node, several parameter acquisition nodes, and at least one data aggregation node. The network coordinator node and the data aggregation node, the parameter acquisition node, and the data aggregation node and the parameter acquisition node are all wirelessly connected using a star topology, forming a wireless sensor-enhanced star network architecture with the data aggregation node as the cluster head. The network coordinator node is used for the control of the entire sensor network system, including time slot allocation, clock synchronization, sleep / wake-up, and network entry / exit of data aggregation nodes and parameter acquisition nodes; the network coordinator node controls the parameter acquisition nodes and data aggregation nodes by sending command parameters. The parameter acquisition node operates under the command parameters sent by the network coordinator node, collects target physical quantity information in real time, and sends the raw measurement signal to the data aggregation node or network coordinator node through a wireless link after local preprocessing. After receiving data from multiple parameter acquisition nodes, the data aggregation node integrates and compresses the data according to a preset fusion algorithm, and forwards the integrated real-time sensor data to the network coordinator node in a predetermined sequence. Simultaneously, the data aggregation node also forwards command parameters sent by the network coordinator node to the parameter acquisition nodes. Specifically, the data integration and compression process, based on the preset fusion algorithm, involves: identifying and merging common fields in the data frames of multiple parameter acquisition nodes in a multi-source heterogeneous wireless sensor network to eliminate cross-node information redundancy; and using a time synchronization and hierarchical scheduling mechanism based on the different sampling frequencies of each parameter acquisition node to reorganize and package the service data of high, medium, and low sampling rate parameter acquisition nodes, aligning and dynamically aggregating data fields to form structured transmission units, thereby increasing the data carrying density of a single wireless transmission.

[0028] The network coordinator node performs format standardization processing on the received integrated real-time sensor data and the locally preprocessed raw measurement signals sent by the parameter acquisition nodes to generate data frames that conform to the interface protocol of the backend status monitoring center, and uploads them to the backend status monitoring center in real time.

[0029] The parameter acquisition node is equipped with wireless high-frequency sampling rate sensors, wireless low-frequency sampling rate sensors, and wireless slowly varying sampling rate sensors to adapt to the measured signals with different dynamic characteristics.

[0030] like Figure 2As shown, parameter acquisition nodes in the network can be directly connected to the network coordinator node, or indirectly connected through aggregation nodes. Aggregation nodes can be used to summarize and integrate measurement data sent by acquisition nodes to match the data transmission volume of sensors with different sampling frequencies in the network. They can also be used for redundant backup, relay transmission, or obstacle avoidance transmission of measurement data from acquisition nodes. In a wireless sensor network system, the network coordinator node is the master node of the entire network system, and the data aggregation nodes or parameter acquisition nodes under the network coordinator node are slave nodes; in a local network centered on the data aggregation node, the data aggregation node is the master node, and the parameter acquisition nodes are slave nodes.

[0031] Communication between the data aggregation node, network coordinator node, and parameter acquisition node follows a preset frame structure and transmission protocol. The preset frame structure includes N periodic network transmission time slots, each of which is further subdivided into L secondary time slots based on actual service load. The length of each secondary time slot is... Furthermore, all network coordinator nodes, parameter acquisition nodes, and data aggregation nodes strictly synchronize their data transmission and reception operations under a global time base.

[0032] like Figure 3 As shown, the sensor network frame length with the network coordinator node as the master node is... It contains N subframes. Each subframe has a length of... It contains M time slots. Each time slot is long. It contains L second-level time slots, each second-level time slot being long. Within the service time slot of the aggregation node, the sensor local network, primarily based on the aggregation node, is further subdivided into two time slots: synchronization, parameters, service (receive), retransmission, and service (transmit). Compared to the time slots of the sensor network primarily based on the network coordinator, this adds one more service (transmit) time slot, while the others remain the same.

[0033] Network transmission time slots are specifically divided into the following four functional time slots: 1. Node synchronization time slots are used to achieve time and state synchronization among all nodes in a wireless sensor network system. 2. Node parameter time slots are used to transmit node configuration parameters and status information; 3. Node service time slots are used to carry real-time sensor data transmission under normal operating conditions; 4. Node retransmission time slots are used to implement reliable retransmission in the event of data loss or bit errors. Each node sends or receives wireless sensor data packets in an orderly manner according to the preset transmission protocol within the corresponding time slot, ensuring the determinism of the data stream and the controllability of the timing.

[0034] The wireless sensor data packets include the following nine categories: 1. Node clock synchronization data packets, used to achieve time base alignment across the entire network; 2. Node entry identification data packet, used to uniquely identify the identity information of a registered node; 3. The node network access request data packet is initiated by the newly joining node to apply for network access; 4. The node access response data packet is returned by the network coordinator node or the aggregation node to confirm access eligibility and resource allocation; 5. Node command parameter data packet, used to issue control commands and parameter configuration commands; 6. Node status parameter data packet, used to report the node's own working status and health indicators; 7. Node status synchronization data packets are used to periodically broadcast the current status of nodes; 8. Node service transmission data packets carry real sensor data and have minimal latency; 9. Node service retransmission data packets, used to trigger reliable retransmission when packet loss or errors are detected; All types of data packets are encapsulated based on the preset frame structure and sent sequentially within the specified time slots. Specifically, node clock synchronization data packets are sent within the node synchronization time slot; node network entry identifier data packets, node network entry request data packets, node network entry response data packets, node command parameter data packets, node status parameter data packets, and node status synchronization data packets are sent within the node parameter time slot; node service transmission data packets are sent within the node service time slot; and node service retransmission data packets are sent within the node retransmission time slot.

[0035] In the preset transmission protocol, except for node service transmission data packets and node service retransmission data packets, the length of all other data packets is a fixed value, and all nine types of data packets are defined with a unique header field, check field, and payload structure.

[0036] The initial network entry of a data acquisition node under a convergence node is assisted by the network coordinator node. The convergence node and its data acquisition nodes first join the control network (i.e., the wireless sensor network) dominated by the network coordinator node. The network coordinator node acquires relevant status parameter information from the convergence and data acquisition nodes, and calculates and configures the local network command parameters based on this information. The convergence and data acquisition nodes receive and save this local network parameter information, and then exit the control network dominated by the network coordinator node. During the wake-up cycle, the data acquisition node receives the clock synchronization signal from the convergence node and joins the local network dominated by the convergence node to begin operation. To change the local network node dominated by the convergence node, both the convergence and data acquisition nodes must first join the control network dominated by the network coordinator node, delete the configured local network parameter information, and then re-establish the local network through the above operations.

[0037] Wireless sensor data aggregation nodes and wireless sensor parameter acquisition nodes are identical in size and structure, differing only in their software. In practice, their specific functions—relay, backup, or obstacle avoidance—are defined by the software program.

[0038] The process of aggregation nodes joining and leaving the network, as well as their hibernation and wake-up, is the same as that of data acquisition nodes directly connected to the network coordinator node. The master node powers on to establish the wireless sensor network and broadcasts node clock synchronization data during the clock synchronization time slot. Aggregation nodes in hibernation mode synchronize their time slots during the wake-up cycle. After the clock synchronization time slot, the network coordinator node continues to broadcast node joining identification data. Once the aggregation node completes clock synchronization, it returns a node joining request based on the received joining identification data, requesting to join the network. Upon receiving the joining request, the master node allocates a transmission time slot corresponding to the amount of data the node will transmit and sends a node joining response data in the corresponding time slot of the next subframe, completing the node's network entry.

[0039] In wireless sensor networks, data acquisition nodes transmit their service data within their allocated time slots at their respective master nodes. Aggregator nodes receive service data from their subordinate data acquisition nodes and integrate and forward this data. During data transmission, the network coordinator node transmits the status of the service data received in the previous subframe during node status synchronization. Data acquisition or aggregation nodes decide whether to retransmit the service data from the previous time slot based on the service data status during the retransmission time slot. The network coordinator node sends command parameter data to the data acquisition or aggregation nodes in turn during fixed time slots, and the data acquisition or aggregation nodes return operational status parameter data within their respective time slots. For redundancy backup, aggregation nodes only receive and forward data from their subordinate data acquisition nodes. Interaction between the network coordinator node and the data acquisition nodes under the aggregation node requires forwarding through the aggregation node.

[0040] In a wireless sensor network with a network coordinator node as the master node, the aggregation node and the data acquisition nodes directly connected to the master node use the same transmission protocol to perform operations such as joining / leaving the network, waking up, and going to sleep via command parameters and status parameters. In a local sensor network with the aggregation node as the master, the data acquisition nodes transmit wireless sensor data packets within the secondary time slots configured by the network coordinator node.

[0041] Working process of a wireless sensor network aggregation node: The specific steps for using the aggregation node and the data acquisition nodes under the aggregation node in a wireless sensor network are as follows: (1) The parameter acquisition node joins the local network with the data aggregation node as the master node. The initial configuration is first completed with the assistance of the network coordinator node. The specific process is as follows: (1.1) The network coordinator node powers on and starts working according to the set frame, subframe and time slot lengths, and sends out default node clock synchronization data packets in fixed time slots; (1.2) After receiving the clock synchronization data packet from the default node, the data aggregation node and the parameter acquisition node apply to join the control network with the network coordinator node as the master node; (1.3) The network coordinator node sends a node entry identification data packet, and the data aggregation node and parameter acquisition node return a node entry request data packet containing the node's physical address and the amount of data transmitted by the node; (1.4) The network coordinator node calculates the local network operating parameters, including the length and number of secondary time slots, based on the received node network access request data packets, combined with the wireless sensor network data transmission rate, frame length, and the number of parameter acquisition nodes. (1.5) The network coordinator node sends node clock synchronization data packets for configuring clock synchronization and node command parameter data packets for configuring time slot allocation to the data aggregation node and the parameter acquisition node under the data aggregation node, respectively, and allocates configuration parameters, including node clock synchronization words, secondary time slot length and number; (1.6) The data aggregation node and the parameter acquisition node under the data aggregation node receive the configuration parameters and return the node status parameter data packet of the configuration clock status and time slot status. The network coordinator node confirms whether the configuration is successful. (1.7) Data aggregation nodes and parameter acquisition nodes save local network status information and exit the wireless sensor network with the network coordinator node as the master node; (2) After the parameter acquisition node joins the local network with the data aggregation node as the master node and completes the initial configuration, it receives the node clock synchronization data sent by the data aggregation node during the wake-up cycle, joins the local network, and starts working. The specific process is as follows: (2.1) The network coordinator node powers on and sends wireless sensor network node clock synchronization data packets in a fixed time slot according to the preset frame structure; (2.2) When the data aggregation node receives the node clock synchronization data packet sent by the network coordinator node, it requests to join the wireless sensor network with the network coordinator node as the master node within the time slot of the wireless sensor network. (2.3) After the data aggregation node joins the wireless sensor network, it starts sending node clock synchronization data packets and node network entry identification data packets in the time slots of the wireless sensor network according to the secondary time slots configured during the initialization of the network coordinator node. (2.4) After receiving the secondary clock synchronization data packet during the wake-up cycle, the parameter acquisition node requests to join the local network with the data aggregation node as the master node; (2.5) After receiving the request for network access data from the parameter acquisition node, the data aggregation node determines whether to allow network access based on the current local network information, and returns a network access response data packet in the next time slot of the wireless sensor network; (2.6) The parameter acquisition node receives the network access response data packet of the node that is allowed to enter the network within the second time slot of the local network, and sends the node service data within the service time slot; (2.7) The data aggregation node receives the service data from the parameter acquisition node, summarizes and integrates the node service data according to a fixed format, and sends out the node service integration data packet in the time slot of the wireless sensor network. (2.8) The network coordinator node receives the node service integration data packet, splits the node service integration data packet, and collects and stores the node physical address according to the corresponding parameters; (3) The data aggregation node and the parameter acquisition node under the data aggregation node have completed the network access. The parameter data and service data between the network coordinator node and the parameter acquisition node under the data aggregation node are transmitted through the data aggregation node. (4) When the data aggregation node goes into hibernation and leaves the network, the local network is disbanded; when the parameter acquisition node under the data aggregation node goes into hibernation and leaves the network, the network coordinator node and the data aggregation node still retain the physical address of the parameter acquisition node under the data aggregation node, and it does not need to be re-completed through the network coordinator node to rejoin the wireless sensor network.

[0042] Example of wireless sensor network design: For example, consider building a sensor network with 6 high-frequency (4.8kHz) sensors, 3 low-frequency (400Hz) sensors, and 16 sensors with a gradually varying (32Hz) sampling rate. Assume that one of the three low-frequency sensors requires a repeater to increase transmission distance, one requires data redundancy backup, and one requires barrier-free transmission. The data update rate for each sensor node is less than 50ms.

[0043] To illustrate the usage of the aggregation node, a sample sensor network scheme is provided, with the connection diagram shown below. Figure 4 As shown in the diagram, the frame result is illustrated below. Figure 5 As shown.

[0044] Detailed explanation: Each frame is designed to last 1 second and contains 20 subframes, each 50 ms long. Each subframe contains 100 time slots, each 500 µs long.

[0045] When the communication rate is set to 400Kbps, each time slot can transmit 200 bits. Each high-frequency, low-frequency, and slowly varying sampling rate sensor service transmission requires at least 10, 1, and 1 time slots respectively. One time slot is allocated per subframe for node clock synchronization, node status synchronization, node command parameter, and node status parameter. Ten time slots are allocated for node service retransmission (the system cannot recover data through retransmission when the probability of packet errors or loss exceeds 10%). Approximately 82 time slots are used for node service transmission (transmission efficiency is approximately 82%). Specifically, the node service transmission time slots are allocated as follows: 60 time slots for 6 high-frequency nodes. Sixteen slowly changing nodes occupy 10 time slots via aggregation node 1; of the three low-frequency nodes, one low-frequency node relays through aggregation node 2, occupying 4 time slots; one low-frequency node's own service transmission occupies 1 time slot, redundant backup transmission through aggregation node 3 occupies 2 time slots, and obstacle avoidance transmission through aggregation node 4 occupies 4 time slots. Five time slots are idle.

[0046] In a local network with the aggregation node as the master node, each secondary time slot is divided into 200µs segments.

[0047] In aggregation node 1, the time slots of the 10 master control nodes are divided into 25 secondary time slots. Specifically, the node clock synchronization time slot and node status synchronization time slot are combined, occupying 1 secondary time slot; the node command parameter time slot and node status parameter time slot are combined, occupying 2 secondary time slots; and the node service retransmission time slot is divided into 1 secondary time slot. The 16 slowly changing node service data receptions occupy 16 secondary time slots, the node service integrated transmission occupies 3 secondary time slots, and 2 secondary time slots are idle.

[0048] The time slots of the four master control nodes under aggregation node 2 and aggregation node 4 are divided into 10 secondary time slots. Among them, the node clock synchronization time slot and the node status synchronization time slot are combined and occupy one secondary time slot, the node command parameter time slot and the node status parameter time slot occupy two secondary time slots, and the node service retransmission time slot occupies one secondary time slot. The low-frequency node service transmission and reception each occupy two secondary time slots, and the remaining two secondary time slots are idle.

[0049] The time slots of the two master control nodes under aggregation node 3 are divided into 5 secondary time slots. Among them, the node clock synchronization time slot occupies 1 secondary time slot, and the low-frequency node service transmission and reception each occupy 2 secondary time slots.

[0050] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

[0051] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. An enhanced star-shaped wireless sensor network system for real-time monitoring, characterized in that: It includes a network coordinator node, several parameter acquisition nodes, and at least one data aggregation node; The network coordinator node and the data aggregation node, the parameter acquisition node, and the data aggregation node and the parameter acquisition node are all wirelessly connected using a star topology, forming a wireless sensor-enhanced star network architecture with the data aggregation node as the cluster head. The network coordinator node is used for the control of the entire sensor network system, including time slot allocation, clock synchronization, sleep / wake-up, and network entry / exit of data aggregation nodes and parameter acquisition nodes; The network coordinator node controls the parameter acquisition node and the data aggregation node by sending command parameters; The parameter acquisition node operates under the command parameters sent by the network coordinator node, collects target physical quantity information in real time, and sends the raw measurement signal to the data aggregation node or network coordinator node through a wireless link after local preprocessing. After receiving data from multiple parameter acquisition nodes, the data aggregation node integrates and compresses the data according to a preset fusion algorithm, and forwards the integrated real-time sensor data to the network coordinator node in a predetermined sequence. At the same time, the data aggregation node also forwards the command parameters sent by the network coordinator node to the parameter acquisition nodes. The network coordinator node performs format standardization processing on the received integrated real-time sensor data and the locally preprocessed raw measurement signals sent by the parameter acquisition nodes to generate data frames that conform to the interface protocol of the backend status monitoring center, and uploads them to the backend status monitoring center in real time.

2. The enhanced star-shaped wireless sensor network system for real-time monitoring according to claim 1, characterized in that: The parameter acquisition node is equipped with a wireless high-frequency sampling rate sensor, a wireless low-frequency sampling rate sensor, and a wireless slowly varying sampling rate sensor to adapt to the measured signal with different dynamic characteristics.

3. The enhanced star-shaped wireless sensor network system for real-time monitoring according to claim 1, characterized in that: The communication between the data aggregation node, the network coordinator node, and the parameter acquisition node follows a preset frame structure and transmission protocol. The preset frame structure includes N periodic network transmission time slots, each of which is subdivided into L secondary time slots according to the actual service load, and the length of each secondary time slot is [missing information]. Furthermore, all network coordinator nodes, parameter acquisition nodes, and data aggregation nodes strictly synchronize their data transmission and reception operations under a global time base.

4. The enhanced star-shaped wireless sensor network system for real-time monitoring according to claim 3, characterized in that: The network transmission time slots are specifically divided into the following four types of functional time slots: Node synchronization time slots are used to achieve time and state synchronization among all nodes in a wireless sensor network system. Node parameter time slots are used to transmit node configuration parameters and status information; Node service time slots are used to carry real-time sensor data transmission under normal operating conditions; Node retransmission slots are used to implement reliable retransmission in the event of data loss or bit errors. Each node sends or receives wireless sensor data packets in an orderly manner according to the preset transmission protocol within the corresponding time slot, ensuring the determinism of the data stream and the controllability of the timing.

5. An enhanced star-shaped wireless sensor network system for real-time monitoring according to claim 4, characterized in that: The wireless sensor data packets include the following nine categories: Node clock synchronization data packets are used to achieve network-wide time base alignment; The node entry identification data packet is used to uniquely identify the identity information of a registered node; The node network access request data packet is initiated by the newly joining node to request network access. The node access response data packet is returned by the network coordinator node or the aggregation node to confirm access eligibility and resource allocation; The node command parameter data packet is used to issue control commands and parameter configuration commands; Node status parameter data packets are used to report the node's own working status and health indicators; Node status synchronization data packets are used to periodically broadcast the current status of nodes; The node service transmits data packets, carrying real sensor data, with minimal latency; Node service retransmission data packets are used to trigger reliable retransmission when packet loss or errors are detected; All types of data packets are encapsulated based on the preset frame structure and sent sequentially within the specified time slots. Specifically, node clock synchronization data packets are sent within the node synchronization time slot; node network entry identifier data packets, node network entry request data packets, node network entry response data packets, node command parameter data packets, node status parameter data packets, and node status synchronization data packets are sent within the node parameter time slot; node service transmission data packets are sent within the node service time slot; and node service retransmission data packets are sent within the node retransmission time slot.

6. An enhanced star-shaped wireless sensor network system for real-time monitoring according to claim 5, characterized in that: In the preset transmission protocol, except for node service transmission data packets and node service retransmission data packets, the length of all other data packets is a fixed value, and all nine types of data packets are defined with a unique header field, check field, and payload structure.

7. An enhanced star-shaped wireless sensor network system for real-time monitoring according to claim 5, characterized in that: After receiving data from multiple parameter acquisition nodes, the data aggregation node performs data integration and compression processing according to a preset fusion algorithm, and forwards the integrated real-time sensor data to the network coordinator node in a predetermined time sequence, specifically: For data in multi-source heterogeneous wireless sensor networks, common fields in data frames from multiple parameter acquisition nodes are identified and merged to eliminate cross-node information redundancy. Based on the different sampling frequencies of each parameter acquisition node, a time synchronization and hierarchical scheduling mechanism is adopted to reorganize and package the service data of high, medium and low sampling rate parameter acquisition nodes, so that data fields are aligned and dynamically aggregated to form structured transmission units, thereby improving the data carrying density of a single wireless transmission.

8. An enhanced star-shaped wireless sensor network system for real-time monitoring according to claim 1, characterized in that: In a wireless sensor network system, the network coordinator node is the master node of the entire network system, and the data aggregation nodes or parameter acquisition nodes under the network coordinator node are slave nodes; in a local network centered on the data aggregation node, the data aggregation node is the master node, and the parameter acquisition nodes are slave nodes.

9. An enhanced star-shaped wireless sensor network system for real-time monitoring according to claim 8, characterized in that: In a local network centered on a data aggregation node, the specific steps for using the data aggregation node and the parameter acquisition nodes under the aggregation node are as follows: (1) The parameter acquisition node joins the local network with the data aggregation node as the master node. The initial configuration is first completed with the assistance of the network coordinator node. The specific process is as follows: (1.1) The network coordinator node powers on and starts working according to the set frame, subframe and time slot lengths, and sends out default node clock synchronization data packets in fixed time slots; (1.2) After receiving the clock synchronization data packet from the default node, the data aggregation node and the parameter acquisition node apply to join the control network with the network coordinator node as the master node; (1.3) The network coordinator node sends a node entry identification data packet, and the data aggregation node and parameter acquisition node return a node entry request data packet containing the node's physical address and the amount of data transmitted by the node; (1.4) The network coordinator node calculates the local network operating parameters, including the length and number of secondary time slots, based on the received node network access request data packets, combined with the wireless sensor network data transmission rate, frame length, and the number of parameter acquisition nodes. (1.5) The network coordinator node sends node clock synchronization data packets for configuring clock synchronization and node command parameter data packets for configuring time slot allocation to the data aggregation node and the parameter acquisition node under the data aggregation node, respectively, and allocates configuration parameters, including node clock synchronization words, secondary time slot length and number; (1.6) The data aggregation node and the parameter acquisition node under the data aggregation node receive the configuration parameters and return the node status parameter data packet of the configuration clock status and time slot status. The network coordinator node confirms whether the configuration is successful. (1.7) Data aggregation nodes and parameter acquisition nodes save local network status information and exit the wireless sensor network with the network coordinator node as the master node; (2) After the parameter acquisition node joins the local network with the data aggregation node as the master node and completes the initial configuration, it receives the node clock synchronization data sent by the data aggregation node during the wake-up cycle, joins the local network, and starts working. The specific process is as follows: (2.1) The network coordinator node powers on and sends wireless sensor network node clock synchronization data packets in a fixed time slot according to the preset frame structure; (2.2) When the data aggregation node receives the node clock synchronization data packet sent by the network coordinator node, it requests to join the wireless sensor network with the network coordinator node as the master node within the time slot of the wireless sensor network. (2.3) After the data aggregation node joins the wireless sensor network, it starts sending node clock synchronization data packets and node network entry identification data packets in the time slots of the wireless sensor network according to the secondary time slots configured during the initialization of the network coordinator node. (2.4) After receiving the secondary clock synchronization data packet during the wake-up cycle, the parameter acquisition node requests to join the local network with the data aggregation node as the master node; (2.5) After receiving the request for network access data from the parameter acquisition node, the data aggregation node determines whether to allow network access based on the current local network information, and returns a network access response data packet in the next time slot of the wireless sensor network; (2.6) The parameter acquisition node receives the network access response data packet of the node that is allowed to enter the network within the second time slot of the local network, and sends the node service data within the service time slot; (2.7) The data aggregation node receives the service data from the parameter acquisition node, summarizes and integrates the node service data according to a fixed format, and sends out the node service integration data packet in the time slot of the wireless sensor network. (2.8) The network coordinator node receives the node service integration data packet, splits the node service integration data packet, and collects and stores the node physical address according to the corresponding parameters; (3) The data aggregation node and the parameter acquisition node under the data aggregation node have completed the network access. The parameter data and service data between the network coordinator node and the parameter acquisition node under the data aggregation node are transmitted through the data aggregation node. (4) When the data aggregation node goes into hibernation and leaves the network, the local network is disbanded; when the parameter acquisition node under the data aggregation node goes into hibernation and leaves the network, the network coordinator node and the data aggregation node still retain the physical address of the parameter acquisition node under the data aggregation node, and it does not need to be re-completed through the network coordinator node to rejoin the wireless sensor network.

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