CN102404817A - Multi-sink node wireless sensor network networking method and system - Google Patents

Abstract

The invention relates to a networking method of a multi-sink-node wireless sensor network, which is characterized by comprising the following steps: step 101, a control server sends a control command for acquiring sensing data to a network according to requirements; 102, the common node is responsible for collecting sensing data and sending the sensing data to the sink node; 103, collecting the collected sensing data by the sink node, sending a sensing data collecting command to the common node, and sending the collected sensing data to the wireless base station; step 104, the time server is responsible for time synchronization of each aggregation node; 105, transmitting the sensing data received by the wireless base station to a data server through a network, and simultaneously transmitting a command for acquiring the sensing data to a sink node, wherein the wireless base station is provided with a long-distance wireless communication module; and step 106, the data server is responsible for storing the acquired sensing data.

Description

Multi-sink node wireless sensor network networking method and system

technical field

The present invention relates to the technical field of wireless sensor networks, in particular to a networking method and system for multi-sinking node wireless sensor networks.

Background technique

Wireless sensor network is a technology that integrates wireless communication, sensor technology, embedded technology and distributed computing. Through the collaborative work between sensor nodes, it can monitor and perceive various environments in real time. The connection between the computing world and the ternary world of human society is therefore also known as the "Internet of Things". Sensor networks have important application value, such as intelligent transportation, environmental monitoring, precision agriculture, national defense and military, smart home, security monitoring, emergency rescue and disaster relief and many other important fields have broad application prospects. At present, the promotion and application of this technology has already begun in many industries, and achieved certain results. With the development of applications and the promotion of technology, the scale of sensor network systems has grown from the initial dozens to hundreds, thousands, and tens of thousands. It can be predicted that sensor network systems with larger and larger scales will emerge in the future.

However, the current networking methods of sensor networks are aimed at small-scale applications and cannot meet the needs of large-scale applications. The existing networking methods can be divided into two categories: one is based on a single-sink node network; the other is based on a multi-sink node network, but there are very large limitations on the scope of application or the network Topology has certain limitations. At present, most of them belong to the first category, and only a few methods belong to the second category. Based on the networking method of a single aggregation node network, one aggregation node is used in the entire network to avoid technical problems such as routing establishment and time synchronization after using multiple aggregation nodes. The network topology of this type of networking method is either cluster, tree, or mesh, and can work well when the network scale is small. However, when the network scale is large, the number of hops from the sensor node to the sink node will increase sharply, and the path will become very long. In addition to the instability of the wireless link itself and the hot spot problem of the sink node, the collected transmission The transmission of sensory data to the aggregation node will experience a large delay, the probability of successful transmission will also be reduced, and the energy consumption caused by a single sensory data transmission will also become very large. Therefore, the life of the network and the success of data collection The rate and delay will be seriously affected.

At present, there are few networking methods based on multi-sink nodes, which can also be divided into two sub-categories: one category is a networking method that can only be applied to belt-shaped monitoring objects such as rivers, and this method has a wide range of applications. limitations. Another sub-category adopts a single-hop cluster networking method with the sink node as the cluster head, so it is limited that the sensor nodes must be within one hop of the sink node, so the scale of the network cannot be too large.

To sum up, the application of large-scale sensor networks urgently needs a networking method with scalability, low energy consumption, and high quality of service for data transmission. The multi-tree networking method based on multi-sink nodes disclosed by the present invention overcomes the shortcomings of single-sink node networking and the current limited multi-sink node networking method. When it is applied to a large-scale sensor network, it has better performance Scalability and energy efficiency, while providing better transmission quality of service.

Contents of the invention

The purpose of the present invention is to overcome the defects of the prior art, design a networking method with scalability, low energy consumption, and high data transmission service quality, and provide key infrastructure for the application of large-scale sensor networks.

A method for networking a wireless sensor network with multiple convergence nodes, characterized in that it comprises the steps of:

Step 101, the control server sends a control command for collecting sensing data to the network according to requirements;

Step 102, the common node is equipped with a short-distance wireless communication module, and the common node is responsible for collecting sensing data and sending it to the sink node;

Step 103, the aggregation node collects the collected sensing data, sends a command to collect the sensing data to the common node, and is responsible for sending the collected sensing data to the wireless base station. The aggregation node is equipped with a short-distance wireless communication module and a long-range Distance wireless communication module;

Step 104, the time server is responsible for the time synchronization of each sink node;

Step 105, the sensing data received by the wireless base station is transmitted to the data server through the network, and at the same time, the command for collecting the sensing data is sent to the convergence node, and the wireless base station is equipped with a long-distance wireless communication module;

Step 106, the data server is responsible for storing the collected sensing data.

The networking method is characterized in that the step 102 also includes:

In step 201, the common node goes through an initialization phase, in which a route is established for the first time, and if the route is established successfully, it enters the synchronous working state; otherwise, it enters the asynchronous working state, and executes step 202;

Step 202, in the asynchronous working state, common nodes establish routes or repair routes.

The networking method is characterized in that the step 201 also includes:

Step 301, in the synchronous working state, common nodes go through a routing update process after working in a low duty cycle mode, and so on;

Step 302, the ordinary node shuts down the microprocessor module, the sensor module and the wireless communication module in the sleep state of each cycle;

Step 303, when the common node is in the active state of each cycle, the node sends data and commands. When the active state ends, it is judged whether the route has failed, and it enters the asynchronous working state to repair the route when it fails; when it is not invalid, it enters dormancy state, execute step 302;

Step 304, the forwarding of the sensing data adopts the strategy of combining directional forwarding and opportunistic forwarding, and the forwarding of the data by the parent node is regarded as an implicit successful reception reply packet, first forwarding to the parent node 3 times, and then broadcasting 3 times Forwarding, forwarding is carried out by a node with a smaller hop count than itself and in a synchronous working state until an implicit successful reception reply packet is received;

Step 305, the forwarding of the control command is forwarded one by one from the sink node to the common node according to the constructed tree topology.

The networking method is characterized in that the step 202 also includes:

Step 401, the aggregation node that has been synchronized with the time server initiates route establishment at the same time, the common node then screens the parent node, estimates the link quality, and selects the best parent node according to the remaining energy and link quality;

Step 402, when the route fails, the ordinary node will start the route repair, select the parent node according to the response packet returned by the adjacent ordinary node working in the synchronous state, estimate the link quality, and select the best parent node according to the remaining energy and link quality ;

Step 403, when a repair fails, try again after hibernation.

The networking method is characterized in that the step 103 also includes:

Step 501: Initialize first, then dormant and active alternately, enter the routing update stage simultaneously with ordinary nodes in the synchronous state.

The networking method is characterized in that the step 501 also includes:

Step 601, after the initialization period begins, the aggregation node acquires time from the time server to realize time synchronization among the aggregation nodes;

Step 602, in the dormant state, the sink node simultaneously turns off modules such as wireless communication, microprocessor, and sensor to enter a low power consumption state;

Step 603, in the active state, the sink node sends commands and data, and assists common nodes in routing repair;

Step 604, after the route update period begins, the aggregation node broadcasts a route establishment packet to start a route update process.

The networking method is characterized in that it also includes:

Step 701, realizing the establishment and maintenance of routing and providing the identification numbers of the parent node and all child nodes of the routing path; the collection of the routing paths constructed forms a plurality of tree topologies with each sink node as the root; each common node The sensing data is forwarded along the path from the normal node to the sink node in a stable state, and will be forwarded opportunistically in an unstable state, and the command of the control server is broadcast from the sink node to the normal node along the tree;

Step 702, realizing the receiving and sending of data packets, the received data is provided by the wireless hardware device, and the transmitted data packets are generated by step 701;

Step 703, classify the data transferred from step 702 through time synchronization management, and execute step 704;

Step 704, finish buffering the data packets to be sent;

Step 705, complete the time control of common nodes and/or sink nodes;

Step 706, monitor the running status of ordinary nodes and/or aggregation nodes, restart itself when software or hardware fails, and respond to maintenance commands such as forced restart and status query injected into the network by the network administrator.

A multi-convergence node wireless sensor network networking system, characterized in that it includes:

Ordinary nodes, used to collect sensing data, are equipped with short-distance wireless communication modules;

The aggregation node is used to collect the collected sensing data and send commands to ordinary nodes, and is also responsible for sending data to the wireless base station, equipped with a short-distance wireless communication module and a long-distance wireless communication module;

The wireless base station is used to transmit the received data to the data server, and also sends the command to the aggregation node, equipped with a long-distance wireless communication module;

Time server, used for time synchronization of each aggregation node;

Data server for permanent storage of collected sensing data;

The control server is used to form and send control commands to the network.

The networking system described above is characterized in that the common node also includes:

The synchronous working state module is used for ordinary nodes to go through an initialization stage, and the route is established for the first time in this stage. If the route is established successfully, it will enter the synchronous working state; otherwise, it will enter the asynchronous working state module;

Asynchronous working state module: used for asynchronous working state, ordinary nodes establish routes or repair routes.

The networking system is characterized in that the synchronous working state module also includes:

The update routing module is used to update the routing process once after the ordinary node works in a low duty cycle mode in the synchronous working state, and so on;

The common node dormant state module is used for the dormant state of common nodes in each cycle, and turns off the microprocessor module, the sensing module and the wireless communication module;

The common node active state module is used for ordinary nodes to send data and commands when the active state is in each cycle. When the active state is over, it is judged whether the route has failed. When it fails, enter the dormant state;

The sensing data forwarding module is used to forward the sensing data using a combination of directional forwarding and opportunistic forwarding, and the forwarding of the data by the parent node is regarded as an implicit successful reception reply packet. First, it forwards to the parent node 3 times, The last is 3 broadcast forwarding, which is forwarded by a node with a smaller hop count than itself and in a synchronous working state until the implicit successful reception reply packet is received;

The control command forwarding module is used to forward the control commands one by one from the aggregation node to the common node according to the tree topology constructed.

The networking system is characterized in that the asynchronous working state module also includes:

The parent node selection module is used to initiate route establishment at the same time by the aggregation node that has been synchronized with the time server. The common node then screens the parent node, estimates the link quality, and selects the best parent node according to the remaining energy and link quality; when the route fails , the normal node will start route repair, screen the parent node according to the response packet replied by the adjacent normal node working in the synchronous state, estimate the link quality, and select the best parent node according to the remaining energy and link quality; when a repair fails, Try again after hibernation.

The networking system is characterized in that the convergence node also includes:

Initialize and update the routing module, which is used for initializing, then dormant and active alternately, and enter the updating routing stage at the same time as the normal nodes in the synchronization state.

The networking system is characterized in that the initialization update routing module also includes:

The initialization module is used to obtain the time from the time server by the aggregation node after the initialization period begins to realize time synchronization between the aggregation nodes;

The sleep mode module of the sink node is used to turn off the wireless communication, microprocessor and sensor modules of the sink node and enter the low power consumption state at the same time in the sleep state;

The active state module of the sink node is used to send commands and data to the sink node in the active state, and assist ordinary nodes to perform route repair; after the update route period begins, the sink node broadcasts the route establishment packet to start the update route process.

The networking system is characterized in that it also includes:

The route establishment and maintenance module is used for the establishment and maintenance of the route and provides the identification numbers of the parent node and all child nodes of the route path. The sensing data of a node is forwarded along the path from the node to the sink node in a stable state, and is forwarded opportunistically in an unstable state, and the command of the control server is broadcast by the sink node to the common node along the tree;

The data classification module is used to classify the data transmitted from the receiving and sending module through time synchronization management, and send it to the queue management module or the route establishment and maintenance module;

The queue management module is used to finish buffering data packets to be sent;

Time synchronization management module, used to complete the time control of the entire node;

The receiving and sending module is used for receiving and sending data packets. The received data is provided by the wireless hardware device, and the sent data packets are generated by the route establishment and maintenance module, or processed by the queue management module through the time synchronization management module passed on;

The network monitoring and maintenance module is responsible for monitoring the running status of nodes, restarting itself when the software or hardware fails, and responding to maintenance commands such as forced restart and status query injected into the network by the network administrator.

Compared with the prior art, the present invention has the following advantages: (1) adopts multi-convergence node networking mode, has better scalability, and supports large-scale networks; (2) comprehensive energy-saving technology, combined with periodic Dormancy, node deep dormancy, and routing selection comprehensively consider energy balance and implicit time synchronization; (3) Periodically update the routing of the entire network to ensure the optimality of routing; (4) Data forwarding adopts directional forwarding (that is, three times to parent node forwarding.) and opportunistic forwarding ("3 broadcast forwarding" is an opportunistic forwarding method, that is, the sender does not know who will help forwarding, and multiple receivers decide whether to forward according to a certain strategy.) Combining, it can take into account Transmission efficiency and reliability; (5) Network monitoring and maintenance can monitor the running status of nodes, and perform self-restart when software or hardware fails, making the network highly reliable. In addition, it can also respond to maintenance commands such as forced restart and status query injected into the network by the network administrator, which is convenient for network maintenance and management; (6) There is a special initialization and debugging period during initialization, which is convenient for the network administrator to install and debug the system on site.

Description of drawings

Fig. 1 is a network topology diagram of the present invention;

Fig. 2 is a routing module structural diagram of the present invention;

Fig. 3 is the state transition figure of common node of the present invention;

Fig. 4 is the synchronous state working timing diagram of common node of the present invention;

Fig. 5 is the working figure of common node of the present invention in active state;

Fig. 6 is a schematic diagram of sending data and commands of common nodes of the present invention;

Fig. 7 is the state transition figure of common node of the present invention in route update state and route repair state;

FIG. 8 is a working sequence diagram of the sink node of the present invention.

Detailed ways

The method and system of the present invention will be further described below in conjunction with the accompanying drawings.

The invention proposes a networking method for a large-scale sensor network. The design of common nodes is characterized by:

(1) Ordinary nodes are divided into synchronous working state and asynchronous working state. Ordinary nodes go through an initialization phase, in which a routing path is established for the first time, and if the route is successfully established, it will enter the synchronous working state; otherwise, it will enter the asynchronous working state.

(2) In the synchronous working state, ordinary nodes work in a low duty cycle mode for several rounds and then go through a routing update process, and so on.

(3) The node shuts down the microprocessor module, the sensing module and the wireless communication module in each cycle of the dormant state. The microprocessor module is responsible for the operation of the entire node, processing and storing the data collected by itself and the data sent by other nodes; the sensor module is responsible for detecting the corresponding environmental information in the area, and will be used to represent the analog voltage signal of these environmental information It is converted into a digital signal through an analog-to-digital conversion unit; the wireless communication module is responsible for communicating with other nodes through wireless signals, exchanging control messages and sending and receiving collected data. (Among them, there is a level of shutdown of the microprocessor module, which involves registers, and the clock part will not be turned off. The sensing module and the wireless communication module are completely turned off.) Enter a low power consumption state.

(4) When the node is in the active state of each cycle, the node sends data and commands, and at the end of the active state, it is judged whether the routing path has failed (enter the asynchronous working state when it fails; enter the dormant state normally when it is not invalid) , should go into asynchronous work state to fix the routing.

(5) Data forwarding adopts the strategy of combining directional forwarding and opportunistic forwarding. The difference between directional forwarding and opportunistic forwarding is: directional forwarding means that a node determines to send to the corresponding node when sending, and the node Forward. And the sending node of opportunistic forwarding is not sure who to send it to, but the receiving node itself determines whether it should be forwarded. And the forwarding of the data by the parent node is regarded as an implicit ACK (Acknowledgment successfully receives the reply packet). There are three kinds of ACKs in this article, each with different meanings. Implicit ACK: It means that the ACK control packet has not been received, but by monitoring whether there are other nodes closer to the sink node than itself to help forward the data packet it just sent. If there is, it means that the data packet sent by itself has been received by the previous node. Thus, data is delivered to nodes closer to the sink. Explicit ACK: Refers to the real ACK packet of the MAC layer, which is an ACK packet in the traditional sense. PROBEACK: It refers to a control packet that the receiver replies after receiving the PROBE packet. It has a one-to-one correspondence with the PROBE package. 7. (Forwarding to the parent node before broadcasting is to improve reliability; the 3 times are based on the results of a large number of experiments in Beijing, Wuxi Taihu, Jiangsu Dafeng, Guangdong Zhaoqing and other places, combined with the results after weighing power consumption.)

(6) The forwarding of commands is forwarded one by one from the sink node to the sub-nodes according to the constructed tree topology.

(7) In the asynchronous working state, the node establishes or repairs the route. The aggregation node that has been synchronized with the time server initiates route establishment at the same time, and the common node then screens the parent node, estimates the link quality, and selects the best parent node according to the remaining energy and link quality. When the route fails, the ordinary node will start the route repair, screen the parent node according to the response packet returned by the neighboring node working in the synchronous state, estimate the link quality, and select the best parent node according to the remaining energy and link quality. When a repair fails, try again after hibernation.

The sink node design is characterized by:

(1) First go through a period of initialization (one of the period of initialization referred to is a parameter that can be set, and the reference value is 60 seconds.), and then sleep and alternately work for a certain period of activity (a certain period is a parameter that can be set, The reference value is 72 cycles.) Afterwards, it enters the update routing stage simultaneously with the common nodes in the synchronous state.

(2) After the initialization period begins, the sink node acquires time from the time server to realize time synchronization among the sink nodes.

(3) During the dormant period, the sink node simultaneously turns off modules such as wireless communication, microprocessor, and sensor to enter a low power consumption state.

(4) During the active period, the sink node sends commands and data, and assists common nodes in routing repair.

(5) After the route update period begins, the aggregation node broadcasts several SETUP packets (routing establishment packets) to start the route update process.

Fig. 1 is the system structural diagram of the present invention, comprises following several parts: (1) common node 101; (2) convergence node 102; (3) wireless base station 103; (4) time server 104; (5) data server 105; (6) Control server 106 .

Among them, the ordinary node 101 is responsible for collecting sensing data, which is equipped with a short-distance wireless communication module; the aggregation node 102 is responsible for collecting the collected sensing data and sending commands to the ordinary node 101, and is also responsible for sending the data to the wireless base station 103 Equipped with a short-distance wireless communication module, such as 802.15.4, responsible for communicating with common nodes. (The short-distance wireless communication module mentioned here refers to: the wireless communication module includes short-distance and long-distance wireless communication modules, and the short-distance wireless communication module is used here.) In addition, the aggregation node 102 is also equipped with WiFi, GPRS, Long-distance wireless communication modules such as GSM or 3G are responsible for accessing the Internet and realizing communication with the time server 104 , the data server 105 and the control server 106 . As shown in Figure 1, the straight solid line in the wireless sensor network indicates short-distance communication, and the line shaped like lightning indicates long-distance communication. The wireless base station 103 is responsible for transmitting the received data to the data server 105, and also sends commands to the aggregation node 102, and is also equipped with long-distance wireless communication modules such as WiFi, GPRS, GSM or 3G. The time server 104 is responsible for the time synchronization of each aggregation node 102; the data server 105 is responsible for permanently storing the collected sensing data; the control server 106 is responsible for forming and sending control commands to the network.

According to application requirements, aggregation nodes and ordinary nodes are randomly deployed in or other application places. First, each aggregation node synchronizes with the time server. After synchronization, the aggregation node interacts with ordinary nodes, and establishes multiple routing trees with the aggregation node as the root through the routing protocol. Among them, an ordinary node is only in one routing tree. After the common node collects the data, it transmits the data to the aggregation node located at the root of the tree through the wireless channel in a multi-hop manner along the routing tree, and the aggregation node transmits it to the data server through the wireless base station. In addition, the commands issued by the control server are transmitted to each convergence node via the wireless base station, and then forwarded to the common nodes by each convergence node. Because the routing mode of the invention supports multiple sink nodes, it is very suitable for large-scale sensor networks.

The common nodes also include:

The synchronous working state module is used for ordinary nodes to go through an initialization stage, and the route is established for the first time in this stage. If the route is established successfully, it will enter the synchronous working state; otherwise, it will enter the asynchronous working state module;

Asynchronous working state module: used for asynchronous working state, ordinary nodes establish routes or repair routes.

The synchronous working status module also includes:

The update routing module is used to update the routing process once after the ordinary node works in a low duty cycle mode in the synchronous working state, and so on;

The common node dormant state module is used for the dormant state of common nodes in each cycle, and turns off the microprocessor module, the sensing module and the wireless communication module;

The common node active state module is used for ordinary nodes to send data and commands when the active state is in each cycle. When the active state is over, it is judged whether the route has failed. When it fails, enter the dormant state;

The sensing data forwarding module is used to forward the sensing data using a combination of directional forwarding and opportunistic forwarding, and the forwarding of the data by the parent node is regarded as an implicit successful reception reply packet. First, it forwards to the parent node 3 times, The last is 3 broadcast forwarding, which is forwarded by a node with a smaller hop count than itself and in a synchronous working state until the implicit successful reception reply packet is received;

The control command forwarding module is used to forward the control commands one by one from the aggregation node to the common node according to the tree topology constructed.

The asynchronous working status module also includes:

The parent node selection module is used to initiate route establishment at the same time by the aggregation node that has been synchronized with the time server. The common node then screens the parent node, estimates the link quality, and selects the best parent node according to the remaining energy and link quality; when the route fails , the normal node will start route repair, screen the parent node according to the response packet replied by the adjacent normal node working in the synchronous state, estimate the link quality, and select the best parent node according to the remaining energy and link quality; when a repair fails, Try again after hibernation.

The aggregation node also includes:

Initialize and update the routing module, which is used for initializing, then dormant and active alternately, and enter the updating routing stage at the same time as the normal nodes in the synchronization state.

The initialization update routing module also includes:

The initialization module is used to obtain the time from the time server by the aggregation node after the initialization period begins to realize time synchronization between the aggregation nodes;

The sleep mode module of the sink node is used to turn off the wireless communication, microprocessor and sensor modules of the sink node and enter the low power consumption state at the same time in the sleep state;

The active state module of the sink node is used to send commands and data to the sink node in the active state, and assist ordinary nodes to perform route repair; after the update route period begins, the sink node broadcasts the route establishment packet to start the update route process.

Fig. 2 is a structural diagram of the routing module of the present invention. Both ordinary nodes and aggregation nodes are equipped with a routing module, which consists of the following parts: (1) routing establishment and maintenance module 201; (2) data classification module 202; (3) queue management module 203; (4) time synchronization management Module 204; (5) receiving and sending module 205; (6) network management and maintenance module 206.

The route establishment and maintenance module 201 mainly implements route establishment and maintenance and provides identification numbers of the parent node and all child nodes of the route path. The set of constructed routing paths forms a plurality of tree topologies with each sink node as the root. The sensing data of each ordinary node is normally forwarded along the path from the node to the sink node, and may be forwarded opportunistically under unstable conditions, and the command of the control server is broadcast by the sink node to the common nodes along the tree. The main job of the data classification module 202 is to classify the data transferred from the receiving and sending modules through time synchronization management, and send them to the queue management module 203 or the route establishment and maintenance module 201 . The main function of the queue management module 203 is to buffer data packets to be sent. The main function of the time synchronization management module 204 is to complete the time control of the entire node. The common node and the convergence node work according to the workflow shown in FIG. 4 and FIG. 8 respectively, and complete different jobs at different time points. The receiving and sending module 205 mainly implements the receiving and sending of data packets, and the received data is provided by wireless hardware devices. The sent data packet is generated by the route establishment and maintenance module, or delivered by the queue management module after being processed by the time synchronization management module. The network monitoring and maintenance module 206 is mainly responsible for monitoring the running status of nodes, and restarting itself when software or hardware fails. In addition, it is also responsible for responding to maintenance commands such as forced restart and status query injected into the network by the network administrator.

Fig. 3 is a state transition diagram of common nodes in the present invention. Ordinary nodes are in one of five states at any time: initialization state 301 , route update state 302 , initial debugging state 303 , sleep state 304 , active state 305 and route repair state 306 .

Step S301, the common node initializes the state immediately after starting, completes the initialization work of the device, and drives the device to enter the update routing state, and executes step S302;

Step S302, the normal nodes in the update routing state interact with the surrounding common nodes and aggregation nodes to determine the route. First, after starting, enter the update routing state from the initialization state. When the path is successfully established (that is, successfully enters a tree and becomes a tree part), then the node enters the initialization debugging state, and executes step S303; otherwise, it enters the routing repair state, and executes step S306; if the repair is successful, it enters the update routing state from the active state, and when the path is successfully updated, the node enters the sleep state, and executes Step S304, otherwise enter the route repair state, execute step S306; because the establishment of the network route is started by each sink node at the same time, under normal circumstances, the common nodes near the sink node complete the route establishment or update first, and then further The node completes routing establishment or update.

Step S303, the initial debugging state is a relatively long node active time provided for the network administrator, so that the network administrator can observe the successful installation of the network.

Step S304, when the INITIAL_WORK_TIME (initial working time) is overtime, the node turns off the radio (radio frequency) and enters the sleep state; the node adopts deep sleep technology in the sleep state, and closes the wireless communication module, the sensor module and the microprocessor module to prolong the working life . After the node is in the sleep state for SYNCHRONIC_SLEEP_TIME (synchronous sleep time) seconds, the node turns on and wakes up its own microprocessor module, sensing module and wireless communication module, enters the active state, and executes step 305 .

Step S305, after the node starts the active state, collects the sensing data, and transmits the sensing data packet to the parent node. Enter the sum of the time of active state again) unsuccessfully send a sensing data packet, then node enters route repairing state, execution step 306; After the node has passed PERIODIC_COUNT (periodic number parameter) small working cycle, node enters update Routing state, execute step S302, otherwise, when the time of the node in active state reaches SYNCHRONIC_WORK_TIME (synchronous working time) seconds, the node returns to sleep state, and execute step S304.

In step S306, the common node interacts with surrounding common nodes and sink nodes in the route repair state to determine the routing path. When the path is established successfully, the node enters the active state and executes step S305.

See Figure 3 for the state transition diagram of the update routing state and the routing repair state. The state after the node has established a path and the state of path reconstruction is called a synchronization state, which includes an initialization state 301 , an update routing state 302 , an initial debugging state 303 , a sleep state 304 and an active state 305 . On the contrary, the routing repair state 306 is called an out-of-sync state. Since the working processes of the update routing state 302 and the routing repair state 306 are similar, the working processes of these two states will be introduced later. Next, firstly, the working process of synchronizing the state.

Fig. 4 is a sequence diagram of the synchronous state work of common nodes.

Step S41, the node is started at the startup time 401, and it will go through the initialization state period 402. At this time, the node is in the initialization state, that is, step S301. During this period, the node completes the initialization of internal variables, resources and hardware;

Step S42, then, enter the route establishment period 403, and the node is in the update route state 302 at this time. During this period, the node interacts with the surrounding nodes to join a built path tree to achieve the purpose of establishing a routing path;

Step S43 , then, the node enters the initial debugging state period 404 , and the node is in the initial debugging state 303 at this time. During this time period, each node transmits a debug packet to the data server to allow the network administrator to determine whether the network was successfully installed. Afterwards, at sleep time 405, the node turns off the sensor module, the wireless module and the microprocessor module to reduce energy consumption. Among them, the total length of the initial state period, route establishment period and initial debugging state period is the initial working time (INITIAL_WORK_TIME);

In step S44, the node enters the dormant state period 406 and the active state period 407 periodically. During the sleep state period 406 the node is in the sleep state 304 for a period of SYNCHRONIC_SLEEP_TIME (synchronous sleep time), and the node is shut down. In the active state period 407 node is in the active state 305, and the length of time is SYNCHRONIC_WORK_TIME (synchronous working time), and one dormant state period 406 and one active state period 407 constitute a small work cycle 409;

Step S45, when the node experiences cycle number parameter (PERIODIC_COUNT) small working cycles, in order to distinguish a large working cycle constituted by PERIODIC_COUNT small working cycles, as shown in Fig. 4, the common node passes through ( 406, 407, 406, 407, ... 408) and then enter (406, 407, 406, 407, ... 408), the large duty cycle refers to (406, 407, 406, 407, ... 408), and the small A duty cycle refers to a single (406, 407). Enter the update routing state period 408, and the node working state is 306 at this time. Wherein, the small duty cycle refers to a dormant state period and an active state period continuous in time. As in the route establishment period 403, the node re-establishes the routing path during this period.

Fig. 5 is a working sequence diagram of common nodes in active state.

Step S501, the node sends data or command 701;

Step S502, in the last 1 second after the end of the active state, the node judges whether it is out of synchronization 702: If the data sent by the node in the past 3 small working cycles has not been successful, that is, the implicit ACK has not been received (successfully received the reply packet), Then the node goes out of synchronicity.

FIG. 6 is a schematic diagram of sending data and commands of a common node.

The sensing data of the nodes are all uplinks, while the commands are all downlinks.

As shown in Figure 6(a), for each data packet generated by the node itself, delivered by the child node or broadcast by the neighbor node with a larger hop than itself, the node will unicast it to the parent node ( Step S601), after its parent node receives, this data packet is unicasted to its parent node (step S602) equally, at the same time, the node listens to the packet forwarded by its parent node, and uses it as an implicit ACK (success Receive the reply packet), thinking that its own data packet has been successfully sent to the parent node. Because the data packet may be lost, the node will try to send the data packet 3 times at intervals until it hears the data packet forwarded by the parent node.

Otherwise, the node will continue to forward in the way shown in Figure 6(b). First of all, the node first broadcasts the data packet (step S603), and after receiving the packet, the adjacent nodes in the synchronous state will forward it to the parent node in the manner shown in Figure 6 (a) (step S604 ), after the node hears the forwarded packet, it thinks that the data packet has been sent successfully, that is, it receives an implicit ACK (successfully receives the reply packet). Similarly, the node broadcasts 3 times until it receives the data packet forwarded by the neighbor node.

Downlink commands are delivered in the manner shown in Figure 6(c). The node broadcasts the received command packet (step S605), and after the child node receives it, it broadcasts to the child nodes of the child node (step S606).

FIG. 7 is a state transition diagram of an ordinary node in the update route state 302 and the route repair state 306 .

Step S701, INIT state (initialization state): when the node enters the updating route state, it enters this state. In this state, set the route recovery timer (RouteRecoveryTimer) as a fixed parameter TIMER_RECOVER_INIT_WAIT, set the update route flag as true (true), own hop count as 255, and the flag variable chooseLargeHopNode as false (false). Because the time of all nodes in the network is synchronized, all nodes in the synchronous state will enter the update routing state at the same time, and the initial establishment and update routing process of the entire route is started by each sink node at the same time. First, the sink node will Broadcast NUM_SETUP_REPEAT (a fixed parameter) SETUP packets (route establishment packets) at intervals, which include the time of the sink node, its own identification number, the connected aggregation node identification number (ie its own identification number), and the number of hops (for 0), electricity. Ordinary nodes that have just established a routing path will also broadcast NUM_SETUP_REPEAT (a fixed parameter) SETUP packets (routing establishment packets) at intervals. When the ordinary node receives the first SETUP packet, it saves the time, identification number, identification number, hop number, power consumption and other information of the neighboring nodes contained in the packet. And reset the route establishment timer SetupRouteTableTimer value to a fixed parameter TIMER_WAIT_GOODNBR. Then enter the 702 state. If the route recovery timer RouteRecoveryTimer times out and does not receive the SETUP packet (route establishment packet), then enter the 708 state.

Step S702, WAIT_FOR_GOODNBR state (waiting for a good neighbor node state of communication): the node mainly waits for a SETUP packet (routing establishment packet) broadcasted by a neighbor node with a better link in this state, and stores all received SETUP packets ( Information such as the time, identification number, identification number of the connected sink node, hop count, and power of the adjacent node carried in the routing establishment packet). When receiving a neighbor node with better link quality, the node resets the route setup timer SetupRouteTableTimer to a fixed parameter TIMER_SETUP_ROUTE_TABLE, and enters the 703 state. Otherwise, after the route establishment timer SetupRouteTableTimer times out, the node enters the 704 state.

Step S703, REBUILD_CONST_NBRTBL state (update routing table state): in this state, the node mainly collects the SETUP packet (routing establishment packet) broadcast by the neighbor node that has established the path, and stores the time, identification number, connected Aggregate information such as node identification number, hop count, and power. When the route establishment timer SetupRouteTableTimer times out, the node enters the 704 state.

Step S704, SIFT_PARENT state: the node in this state mainly judges whether it has received a SETUP packet (routing establishment packet), and screens out all adjacent nodes that can be candidate parent nodes. When the large hop number selection flag variable (chooseLargeHopNode) is true (true), the neighboring nodes that have received its SETUP packet (routing establishment packet) can be used as candidate parent nodes; otherwise, only nodes with a smaller hop number than itself can as a candidate parent node. If never received any SETUP packet (route establishment packet), iFailureSetup<MAX_NUM_FAILURE_SETUP (that is, the failure count variable is less than a certain parameter) and the reset flag is set to true (true), then the node enters the 711 state; if never received any SETUP packet ( Routing establishment package), iFailureSetup<MAX_NUM_FAILURE_SETUP (that is, the failure count variable is less than a certain parameter) and the reset flag is set to false (false), then the node enters the 710 state; if no SETUP package (routing establishment package) has been received, iFailureSetup=MAX_NUM_FAILURE_SETUP (that is, the failure count variable is equal to a certain parameter), then the node enters the 712 state. After the screening is completed, if there is no candidate parent node and iFailureSetup<MAX_NUM_FAILURE_SETUP (that is, the failure count variable is less than a certain parameter), the node enters the 711 state; if there is no candidate parent node and iFailureSetup=MAX_NUM_FAILURE_SETUP (that is, the failure count variable is equal to a certain parameter), the node enters 712 state; otherwise, if there is a candidate parent node, enter 705 state.

Step S705, CHECK_BILINK state (confirming bidirectional link state): the main task of this state is to detect the quality of the bidirectional link between the node and each candidate parent node. The detection method is to send fixed parameter NUM_CHECK_REPEAT CHECK packets (confirmation packets) that require explicit ACK (successful reception) to each candidate parent node, and count the number of successful transmissions of CHECK packets (confirmation packets) as an estimate of link quality. The explicit ACK mentioned here refers to: the real ACK packet of the MAC layer, which is an ACK packet in the traditional sense.

Step S706, CHOOSE_PARENT state (choose parent node): the task of this state is to judge whether there is a candidate parent node with sufficient link quality, and select an optimal parent node according to the link quality and remaining power of the candidate parent node. If there is no candidate parent node with good enough link quality in the received SETUP packet (routing establishment packet), and iFailureSetup<MAX_NUM_FAILURE_SETUP (that is, the failure count variable is less than a certain parameter), then the node enters the 711 state; if the received SETUP packet ( There is no candidate parent node with good enough link quality in the route setup packet), and iFailureSetup=MAX_NUM_FAILURE_SETUP (that is, the failure count variable is equal to a certain parameter), then the node enters the 712 state. If there is a candidate parent node with sufficient link quality, an optimal parent node is selected. The selection criterion of the optimal parent node is the candidate parent node with the largest alpha*link quality+(1-alpha)*remaining power value, where alpha is a fixed parameter. Then, set your own time as the time of the selected parent node, destroy the neighbor table and broadcast NUM_SETUP_REPEAT (a fixed parameter) SETUP packets (routing establishment packets) at intervals, and then enter the 707 state.

Step S707, NORMAL state (normal working state): reaching this state indicates that the routing path has been established. When entering this state, save the identification number of the sink node, the identification number of the parent node, and its own hop count (the hop count of the parent node + 1). If a PROBE packet (probe packet) is received in this state, a PROBEACK packet (probe reply packet) is responded. The PROBEACK packet here refers to a control packet that the receiver replies after receiving the PROBE packet, which corresponds to the PROBE packet one by one. Receiving a PROBE packet (probe packet) means that there are nearby neighboring nodes that are not in the route repair state. The reply PROBEACK packet (detection reply packet) includes the time of the sink node, its own identification number, the connected sink node identification number (ie its own identification number), the hop count (0), and the power.

Step S708, NO_ROUTE state (no route state): when the node enters the route restoration state, it will enter this state, and a route restoration process will start from here. In this state, the node ensures that the radio (radio frequency) is turned on, then sends a PROBE packet (probe packet), and sets the routing table establishment timer SetupRouteTableTimer as a fixed parameter TIMER_SETUP_ROUTE_TABLE, sets the update routing flag as false (false), and then enters 709 status. Neighboring nodes in the synchronization state will reply PROBEACK packets (probe reply packets) after receiving the PROBE packets (probe packets).

Step S709, RECOVER_CONST_NBRTBL state (routing table repair state): when the node is in this state, it collects PROBEACK packets (probe reply packets) to construct a neighbor table. Whenever a PROBEACK (detection reply packet) is received, information such as the time of the sink node, its own identification number, the identification number of the connected sink node (ie its own identification number), the number of hops (0), and the power is stored. When the routing table establishment timer SetupRouteTableTimer times out, the node enters the 704 state.

Step S710, LONG_WAIT state (long waiting state): this state is a dormant long waiting state. When a node enters this state, the wireless module and the microprocessor module are turned off. Add 1 to the failure count variable iFailureSetup, indicating that a repair process fails, and set the route repair timer RouteRecoverTimer to a fixed parameter TIMER_RECOVER_LONG_WAIT value. When the route recovery timer RouteRecoverTimer times out, it enters the 708 state.

Step S711, SHORT_WAIT state (short wait state): this state is a non-sleep short wait state. When a node enters this state, it also indicates that a recovery process has failed, and the route recovery timer RouteRecoverTimer is set to a fixed parameter TIMER_RECOVER_SHORT_WAIT value. When the route recovery timer RouteRecoverTimer times out, it enters the 708 state.

Step S712, TRY_LARGE_HOP state (try large hop state): when the node enters this state, it also indicates that the repair process has failed for many times in a row, and it has been unable to find a good enough link among neighboring nodes in the synchronization state whose hop count is smaller than itself the parent node of . The node sets the large hop count selection enable counter EnableLargerHopTimer to 2*T_DUTY_CYCLE, where T_DUTY_CYCLE is the time length of a single cycle. After the counter was overtime, set the large hop number selection flag variable chooseLargeHopNode to be true (true), so that in the repair process thereafter, the node will be able to select a node with a lower hop number than itself as the parent node.

Among the above states, the state sequence of updating routing state is 701, 702, 703, 704, 705, 706 and 707. The sequence of states in the route repair state is 708, 709, 704, 705, 706, 710, 711, 712, and 707.

FIG. 8 is a working sequence diagram of the sink node. Its working and sleeping time control is similar to that of ordinary nodes working in a synchronous state. After the node is started, it is a long working time. At the beginning of this working time, the sink node obtains the time from the time server and sets it as its own time (step 801). Then, send fixed parameter NUM_SETUP_REPEAT (a fixed parameter) SETUP packets (routing establishment packets) at intervals (step 803). Sending of commands and data then begins (step 802). After the work is completed, the fixed parameter PERIODIC_COUNT small work cycles are started, and commands or data are sent during the active time of each small work cycle. At the beginning of the subsequent update routing state period, the fixed parameter NUM_SETUP_REPEAT SETUP packets (routing establishment packets) are sent at intervals again. When transmitting data sent by common nodes, it is sent to the data server through the wireless base station. After receiving the command sent by the control server from the wireless base station, forward it to all child nodes. After receiving the PROBE packet (probe packet), the sink node replies with a PROBEACK packet (probe reply packet).

Various modifications can be made to the above contents by those skilled in the art without departing from the spirit and scope of the present invention defined by the claims. Therefore, the scope of the present invention is not limited to the above description, but is determined by the scope of the claims.

Claims (14)

1. a poly concourse nodes networking method of wireless sensor network is characterized in that, comprises the steps:

Step 101 is sent the control command of gathering sensing data by Control Server in network according to demand;

Step 102, ordinary node is equipped with short-range wireless communication module, is responsible for gathering sensing data by ordinary node, sends to aggregation node;

Step 103; Collect the sensing data that collects by aggregation node; And to the order that ordinary node sends the collection sensing data, be responsible for simultaneously the sensing data that collects is sent to the wireless base station, aggregation node is equipped with short-range wireless communication module and long distance wireless communication module;

Step 104 is responsible for the time synchronized of each aggregation node by time server;

Step 105, the sensing data that is received by the wireless base station sends data server to through network, and the order that will gather sensing data simultaneously sends to aggregation node, and the wireless base station is equipped with long distance wireless communication module;

Step 106 is responsible for the sensing data of storage of collected by data server.

2. network-building method as claimed in claim 1 is characterized in that, said step 102 also comprises:

Step 201, initial phase of ordinary node experience is set up route for the first time in this stage, if set up the route success then get into the synchronous working state; Otherwise, get into asynchronous operating state, execution in step 202;

When step 202, asynchronous operating state, ordinary node is set up route or is repaired route.

3. network-building method as claimed in claim 2 is characterized in that, said step 201 also comprises:

Step 301, under the synchronous working state, ordinary node with the work of low duty ratio periodic mode after experience once upgrade routing procedure, circulation according to this;

Step 302, ordinary node are closed microprocessor module, sensing module and wireless communication module at the dormant state in each cycle;

Step 303, ordinary node are when the activity attitude in each cycle, and node sends data and order, when the activity attitude finishes, judges whether that route lost efficacy, when losing efficacy, get into asynchronous operating state to repair route; When not losing efficacy, get into dormant state, execution in step 302;

Step 304; The forwarding of sensing data adopts directed forwarding and chance to transmit the strategy that combines; And father node replied bag to this forwarding of data as the successful reception of implicit expression, transmitted to father node for 3 times before this, after be that 3 broadcasting is transmitted; Transmit by and node that be in the synchronous working state littler, till receiving that implicit expression successfully receives the answer bag than own jumping figure;

Step 305, the forwarding of control command is transmitted to ordinary node from aggregation node according to the tree topology that makes up one by one.

4. network-building method as claimed in claim 2 is characterized in that, said step 202 also comprises:

Step 401 is set up by initiating route simultaneously with the synchronous aggregation node of time server, and ordinary node rescreens and selects father node, estimates link-quality, selects best father node according to dump energy and link-quality;

Step 402, when route lost efficacy, ordinary node can start route repair, according to the respond packet screening father node that the adjacent ordinary node that is operated in synchronous regime is replied, estimated link-quality, selected best father node according to dump energy and link-quality;

Step 403 behind a repairing failure, is attempted after the dormancy once more.

5. network-building method as claimed in claim 1 is characterized in that, said step 103 also comprises:

Step 501, first initialization after dormancy then, the activity alternation, gets into the renewal route stage with the ordinary node that is in synchronous regime simultaneously.

6. network-building method as claimed in claim 5 is characterized in that, said step 501 also comprises:

Step 601, after initialization period began, aggregation node was realized the time synchronized between each aggregation node to the time server acquisition time;

Step 602, at dormant state, aggregation node is closed modules such as radio communication, microprocessor and sensing simultaneously and is got into low power consumpting state;

Step 603, in the activity attitude, aggregation node sends order and data, and assists ordinary node to carry out route repair;

Step 604, after the renewal route period began, aggregation node broadcasting route was set up bag and is started the renewal routing procedure.

7. network-building method as claimed in claim 1 is characterized in that, also comprises:

Step 701 realizes the foundation and the maintenance of route and the father node of routed path and the identification number of all child nodes is provided; It is the tree topology of root with each aggregation node that the set of the routed path of being constructed forms a plurality of; The sensing data of each ordinary node is transmitted in the path of stable state along this ordinary node to aggregation node, can transmit with the chance mode in labile state, and the order of Control Server is broadcast to ordinary node by aggregation node along tree;

Step 702 realizes the reception and the transmission work of packet, and the data of reception are provided by radio hardware equipment, and the packet of transmission is produced by step 701;

Step 703 is classified execution in step 704 from step 702 through the data that the time synchronized management passes over;

Step 704 is accomplished buffer memory packet to be sent;

Step 705 is accomplished the time control of ordinary node and/or aggregation node;

Step 706, monitoring ordinary node and/or aggregation node running status, when software or hardware fault, oneself is restarted, maintenance commands such as the response to network keeper pressure of injecting network is simultaneously restarted, status poll.

8. a poly concourse nodes wireless sensor network constructing system is characterized in that, comprising:

Ordinary node is used to gather sensing data, and it is equipped with short-range wireless communication module;

Aggregation node is used to collect the sensing data that collects and sends order to ordinary node, also is responsible for sending the data to the wireless base station, is equipped with short-range wireless communication module, also is furnished with long distance wireless communication module;

The wireless base station is used for sending the data of receiving to data server, also order is sent to aggregation node, is equipped with long distance wireless communication module;

Time server is used for the time synchronized of each aggregation node;

Data server is used for the sensing data that permanent storage is gathered;

Control Server is used for according to formation with to the network transmitting control commands.

9. group network system as claimed in claim 8 is characterized in that, said ordinary node also comprises:

The synchronous working block of state is used for initial phase of ordinary node experience, sets up route for the first time in this stage, if set up the route success then get into the synchronous working state; Otherwise, get into asynchronous operation state module;

Asynchronous operation state module: when being used for asynchronous operating state, ordinary node is set up route or is repaired route.

10. group network system as claimed in claim 9 is characterized in that, said synchronous working block of state also comprises:

Upgrade routing module, be used under the synchronous working state, ordinary node with the work of low duty ratio periodic mode after experience once upgrade routing procedure, circulation according to this;

Ordinary node dormant state module is used for ordinary node at the dormant state in each cycle, closes microprocessor module, sensing module and wireless communication module;

The movable morphotype piece of ordinary node is used for ordinary node when the activity attitude in each cycle, and node sends data and order, when the activity attitude finishes, judges whether that route lost efficacy, when losing efficacy, gets into asynchronous operating state to repair route; When not losing efficacy, get into dormant state;

The sensing data forwarding module; The forwarding that is used for sensing data adopts directed forwarding and chance to transmit the strategy that combines; And father node replied bag to this forwarding of data as the successful reception of implicit expression, transmitted to father node for 3 times before this, after be that 3 broadcasting is transmitted; Transmit by and node that be in the synchronous working state littler, till receiving that implicit expression successfully receives the answer bag than own jumping figure;

The control command forwarding module, the forwarding that is used for control command is transmitted to ordinary node from aggregation node according to the tree topology that makes up one by one.

11. group network system as claimed in claim 9 is characterized in that, said asynchronous operation state module also comprises:

Father node is selected module, is used for setting up by initiating route simultaneously with the synchronous aggregation node of time server, and ordinary node rescreens and selects father node, estimates link-quality, selects best father node according to dump energy and link-quality; When route lost efficacy, ordinary node can start route repair, according to the respond packet screening father node that the adjacent ordinary node that is operated in synchronous regime is replied, estimated link-quality, selected best father node according to dump energy and link-quality; Behind a repairing failure, attempt once more after the dormancy.

12. group network system as claimed in claim 8 is characterized in that, said aggregation node also comprises:

Routing module is upgraded in initialization, is used for first initialization, after dormancy then, the activity alternation, gets into the renewal route stage simultaneously with the ordinary node that is in synchronous regime.

13. group network system as claimed in claim 12 is characterized in that, said initialization is upgraded routing module and is also comprised:

Initialization module is used for after initialization period begins, and aggregation node is realized the time synchronized between each aggregation node to the time server acquisition time;

Aggregation node dormant state module is used at dormant state, and aggregation node is closed modules such as radio communication, microprocessor and sensing simultaneously and got into low power consumpting state;

The movable morphotype piece of aggregation node is used in the activity attitude, and aggregation node sends order and data, and assists ordinary node to carry out route repair; After the renewal route period began, aggregation node broadcasting route was set up bag and is started the renewal routing procedure.

14. group network system as claimed in claim 8 is characterized in that, also comprises:

Route is set up maintenance module; Be used for the foundation and the maintenance of route and the father node of routed path and the identification number of all child nodes are provided; It is the tree topology of root with each aggregation node that the set of the routed path of being constructed forms a plurality of; The sensing data of each ordinary node in the stable state lower edge this node transmit to the path of aggregation node, can transmit under labile state, and the order of Control Server is broadcast to ordinary node by aggregation node along tree with the chance mode;

The data qualification module is used for classifying through the data that the time synchronized management passes over from receiving sending module, sends into queue management module or route is set up maintenance module;

Queue management module is used to accomplish buffer memory packet to be sent;

The time synchronized administration module is used to accomplish the time control of whole node;

Receive sending module; Be used for the reception and the transmission work of packet; The data that receive are provided by radio hardware equipment, and the packet of transmission is set up maintenance module by route and produced, or pass over after the time synchronized administration module is handled by queue management module;

The network monitor maintenance module is used for being responsible for the monitoring node running status, and when software or hardware fault, oneself is restarted, maintenance commands such as the response to network keeper pressure of injecting network is simultaneously restarted, status poll.

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