CN102711209B - Dynamic self-organizing hierarchical routing method applied to wireless sensor network - Google Patents

Abstract

The invention relates to a dynamic self-organizing hierarchical routing method. This method is applicable to the problem that the path failure data cannot be transmitted due to node movement or failure in the wireless sensor network tree topology, and can realize the dynamic adjustment of the network topology. The invention establishes a network based on a multi-fork tree topological structure, and each node maintains a hierarchical routing table, and records the subtree topological structure with the node as the root. The routing table effectively updates the routing table by inserting serial numbers when applying for node access, which solves the problem of repeated node numbers in the routing table of upper nodes. In order to take into account energy and computing overhead as well as the real-time performance of data transmission, the routing table reorganizes the topology structure only when the data cannot be transmitted, maintains the topology structure in the network in time, and reduces overhead while ensuring reliable data transmission. Take advantage of active and passive routing protocols.

Description

A Dynamic Self-Organizing Hierarchical Routing Method for Wireless Sensor Networks

technical field

The invention relates to a dynamic self-organizing hierarchical routing method suitable for wireless sensor networks. This method can overcome the influence of node failure on data transmission in the wireless sensor network, and realize the dynamic adjustment of the network topology. The invention belongs to the technical field of wireless sensor networks.

Background technique

Wireless Sensor Network (WSN) is a fully distributed system without a central node. A large number of sensor nodes are densely deployed in the monitoring area. These sensor nodes are integrated with sensors, data processing units and communication modules, which are connected through wireless channels to form a self-organized network system. Micro sensor technology and wireless communication capability between nodes endow wireless sensor networks with broad application prospects. As a ubiquitous sensing technology, wireless sensor networks are widely used in military, environmental, medical, household and other commercial and industrial fields; it also has unique technical advantages in special fields such as space exploration, anti-terrorism, and disaster relief.

Wireless sensor networks work in a certain physical environment, which is affected by comprehensive factors such as mutual interference between wireless channels, intermittent wireless communication links, network task load changes caused by emergencies, equipment failures, terrain and weather, etc. The network topology formed by wireless channels between sensor nodes may change at any time, and the change method and speed are difficult to predict. These changes often seriously affect the function of the system, which requires the sensor nodes to adjust their communication working status in a timely manner as the environment changes.

The tree topology protocol widely used in wireless sensor networks cannot effectively solve the above-mentioned change problems when nodes move or fail, which directly leads to path failure and data cannot be transmitted, and will cause excessive energy consumption of some nodes, affecting the system. issues such as service life. For the network as a whole, the accuracy, completeness and timeliness of network monitoring information will be greatly affected.

The data-centric wireless sensor network takes the efficient use of energy as the primary design goal and focuses on obtaining effective information from the outside world. The dynamic adjustment function of the network topological structure of the present invention can effectively reduce the impact of node failure on data transmission in the wireless sensor network.

The domestic invention patent with the application number of 200710172037.2 and the application date of December 6, 2007 discloses a method for forming a tree routing method for a wireless ad hoc network used in a monitoring system. The routing method can provide a routing protocol for fast routing establishment and dynamic maintenance for mobile node communication in a wireless multi-hop network environment. This patent uses centralized routing table management and storage, which is not suitable for sensor networks with limited single-node capabilities. The present invention uses a distributed routing table maintenance mechanism to make the application of this route on large-scale sensor networks possible. Compared with this patent, the present invention abandons the simple least-priority algorithm for the number of paths when selecting a parent node, and uses a multi-indicator combination priority algorithm based on QoS network, which can improve the quality of network communication. In addition, we adopt a method different from the traditional active routing method to update the routing table by querying according to the set interval, and also different from the traditional passive routing method that often requires route discovery, that is, only when an error occurs in a certain transmission link. The path is re-established, and in order to minimize the overhead, the link is only re-established when the data cannot be transmitted, so that the data can continue to be transmitted normally. And the above-mentioned patent only expounds the algorithm of route establishment, but does not elaborate the solution of data transmission in route.

The domestic invention patent application with application number 201010265626.7 and application date of August 27, 2010 discloses a multi-path routing protocol suitable for wireless sensor networks. The routing protocol uses a tree-based multi-path routing protocol to alleviate the problems of sensor network protocol delay and poor network reliability, and adopts a mesh tree topology to improve the robustness of the network. The process described in the method repairs the routing table through the backup multi-path, which is not suitable for the sensor network with limited single node capability. The present invention selects a multi-index combination priority algorithm based on QoS network, which can further improve the network communication quality.

The domestic invention patent application with the application number of 201110033643.2 and the application date of January 31, 2011 discloses a routing method and device and sensor equipment based on a tree-shaped wireless sensor network. The routing method is to assign short addresses to the sensor nodes in advance according to the layers of each sensor node in the tree network and the position in the layer, so as to improve the routing transmission efficiency of the sensor nodes in the process of message forwarding. Different from the present invention, the process described in this method needs to forward data through the preset tree-shaped routing table, and does not involve the repair function of the routing table.

Contents of the invention

The technical problem to be solved by the present invention is to provide a set of methods for reorganizing the topology structure for the network in the case of node movement or failure in the wireless sensor network, which leads to path failure data that cannot be transmitted, effectively reducing the above-mentioned common problems in the wireless sensor network. Problems that affect system data transmission and realize dynamic adjustment of network topology.

In order to solve the above problems, the technical scheme adopted by the present invention is as follows:

The network established by the present invention is a topology structure based on multi-fork tree. At the beginning of the establishment of the network, all nodes in the entire area do not have any information about neighboring nodes. At this time, a designated node, which can be regarded as a sink node in the sensor network, will initiate a broadcast to establish a network. Neighboring nodes that receive this broadcast will use the node that sent this broadcast as a potential parent node, and send a request to the parent node to become its child node. After receiving the feedback from the parent node that the join is successful, it will continue to send to the next layer Broadcast network construction, search for the next layer of nodes, and so on, until all nodes in the area are covered.

Each node i in the entire network maintains a routing table, which records the topology of the subtree rooted at node i, and maps the topology of the tree structure into a one-dimensional linear list for easy management and maintenance in nodes with limited computing and storage capacity. Each new node that joins the network will report the information of the new access node through unicast layer after layer after receiving the confirmation from the parent node, and the node that receives this message will Updates the entire tree subnet rooted at it. Thus, a hierarchical routing table is established.

In the actual network, there are factors such as unequal communication distance between nodes and external interference, which may cause some problems in the network. For example, the parent node can receive the network access application of the new child node, but the child node cannot receive it. The access success signal sent by the parent node. In this case, in order to ensure the two-way effective transmission of data, the child node will establish a parent-child relationship with other nodes by accepting broadcasts from other nodes or actively sending out information seeking to access the network. In this case, there will be two possibilities. For example, the child node sends an application to the parent node but does not receive the acknowledgment ACK, and instead sends an application to other nodes to request access to the network, but in fact the parent node receives the application request ; Another example is that after the child node submits the network access application to the parent node, the parent node returns the confirmation message Response and thinks that the child node has received it, but in fact the child node has not received the confirmation message Response, and thinks that the application is unsuccessful, and turns to Seek other access points. In the above two cases, the parent node will treat the child node as a successful application, and report to the upper layer node to update the upper layer routing table. In fact, this node accesses the network through other nodes, which causes the problem of repeated node numbers in the routing table of the upper node, which leads to the inability to correctly select the appropriate path to transmit data.

We effectively update the routing table by inserting the sequence number in the node's access application. As long as each node sends an access application once, its internal serial number will be accumulated. When the upper layer node receives the information of updating the routing table, it will judge whether the sequence number of the node to be updated is newer than that in the original routing table. If it is a new path, delete the subtree headed by the node in the original routing table, and refresh the routing table according to the updated information.

At the same time, the present invention establishes a topology dynamic organization mechanism to solve the problem of data transmission failure due to various reasons in the actual wireless network operation process, such as the node of the next hop moves beyond the transmission range, the node is abnormal and causes restart or Failure due to energy depletion. In order to ensure the reliable transmission of data, the topology needs to be reorganized. In order to take into account energy and computing overhead as well as the real-time performance of data transmission, the present invention uses a query method to update the routing table according to the set interval, which is different from the traditional active routing method, and is also different from the traditional passive routing method that often needs to perform route discovery. The present invention The path is re-established only when an error occurs in a certain transmission link, and in order to minimize the overhead, the link is re-established only when the data cannot be transmitted, so that the data can continue to be transmitted normally.

When data cannot be transmitted, topology reorganization is divided into two cases, one is uplink transmission and the other is downlink transmission.

The situation of uplink data transmission includes the transmission of collected data to the sink node (generally considered as the root node of the whole tree), and when transferring data between two points in the network, the destination node is not in the subtree rooted at this node, but Send information to its parent node etc. During uplink data transmission, there are two types of transmission failures. The first is that the next hop node (that is, the parent node) moves out of the transmission range or fails, resulting in the failure of data transmission. At this time, if the number of transmission failures exceeds the set threshold, it will find a new parent node through broadcasting and re-connect to the network. The second is that the next-hop node loses routing information due to restart or other reasons, and cannot perform data transmission. When the received data needs to be forwarded, the error information will be fed back to the previous hop node. At this time, the previous hop node that received the Error message will also search for a new parent node through broadcasting. If each node in the uplink transmission line fails to find the path to the destination node in the routing table it maintains, the finally forwarded data packet will arrive at the sink node, and an abnormal message will be generated.

The situation of downlink data transmission includes the sink node sending control information to other nodes in the network, and when transmitting data between two points in the network, the destination node is located in the subtree rooted at this node, and the information will be sent to the corresponding child node . In the downlink data transmission, two transmission failure situations may also occur. The first is that the data cannot be received by the next hop node (a child node of this node). At this time, as long as the number of transmission failures exceeds the set threshold, the node will initiate a broadcast to search, and as long as the node that stores the path to the destination node will respond, the node will select the node with the closest hierarchy as a child node, so that Fix broken paths. If the next hop node is the destination node, and the destination node is lost at this time and data cannot be transmitted, the abnormal information will be sent back to the sink node. The second is also that the next hop node (non-destination node) is abnormal and loses the path information. At this time, the Error information will be fed back, and after receiving the Error information, the node will broadcast to find the next hop node and repair the downlink path.

New nodes join the network. In a dynamically organized network, not only the nodes in the original network fail to exit, but also new nodes will come in. For a node that wants to send sensing data to the sink node but has not yet joined the network, there is no routing information. First, the node will broadcast to search for neighboring nodes as network access points. After getting the reply from the neighboring nodes, select a certain node as the access point, and establish the parent-child relationship. The parent node with a new child node will report the information of the new child node to the upper layer and update it sequentially.

The present invention utilizes the dynamic self-organizing hierarchical routing method of wireless sensor network, and the beneficial effects that can be achieved are as follows:

This routing method mainly provides a set of methods for reorganizing the topology structure for the situation that the node moves or fails to cause the path failure data to be unable to be transmitted in the tree topology widely used in the current wireless sensor network routing protocol. This routing method not only ensures that the data can be sent back from the sensor node to the sink node more reliably, but also realizes the mutual communication between any nodes in a similar wireless Ad-Hoc Networks (Ad-Hoc Networks), without the need for forwarding through the sink node , thereby alleviating the problem of excessive consumption of energy hotspots near the sink node. At the same time, due to the effective maintenance of the routing table in the network, this routing method can give full play to the advantages of short transmission delay and high burst data transmission rate of the Proactive Protocol, and can dynamically organize the topology structure in a certain To a certain extent, the passive routing protocol (Reactive Protocol) has strong dynamics and is not easily affected by the failure of routing nodes.

Description of drawings

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

Figure 1 is a schematic diagram of network broadcasting;

Figure 2 is a schematic diagram of node access to the network during network construction;

FIG. 3 is a schematic diagram of a node successfully accessing the network;

Fig. 4 is a schematic diagram of mutual communication between members in the subtree;

Fig. 5 is a schematic diagram of routing confusion;

Figure 6 is a schematic diagram of routing table maintenance;

FIG. 7 is a schematic diagram of situation 1 of uplink transmission failure;

FIG. 8 is a schematic diagram of the second case of uplink transmission failure;

FIG. 9 is a schematic diagram of situation 1 of downlink transmission failure;

FIG. 10 is a schematic diagram of the second case of downlink transmission failure;

FIG. 11 is a schematic diagram of updating the routing table when a new node accesses the network.

Detailed ways

Further description will be given below with specific implementation examples in conjunction with the accompanying drawings.

The specific process of establishing a hierarchical network topology and establishing a routing table is as follows:

Step 1: First, the set root node Node 1 (usually considered as a sink node) initiates the network construction broadcast BroadForNet, see Figure 1. The broadcast packet mainly includes the ID of the root node and the level.

Step 2: The node that has received the BroadForNet message and has not yet joined the network will use the node ID that sent this message as a potential parent node, and send a JoinIn message to it, requesting to become its child node to join the network. If this method is applied to the wireless sensor network, considering that the sensor nodes are limited by energy and the processing capacity is quite limited, it is difficult to process the joining applications of multiple sub-nodes in a short time slot, especially when the node density is high. . Here, each node will randomly delay for a period of time within a set period of time after receiving BroadForNet, and then send a JoinIn request to avoid intensive access of multiple nodes.

Step 3: The parent node that receives the JoinIn application message from the child node will send back a ReJoinIn feedback message to inform the child node applying whether the application is successful. Some judgments can be added here, such as whether the number of child nodes supported by the parent node has exceeded. In order to ensure QoS, it is recommended that this child node connect to other parent nodes; or the quality of the received lqi is too poor, lower than a certain Threshold, etc., these can be used as selection conditions for establishing a link. Through this kind of information transmission between the parent and child nodes, the situation of unequal communication distance between the two parties in the actual situation can be avoided, and it is guaranteed that as long as the parent-child relationship can be established, the two parties can send and receive information to each other. If the child node application is successful, the parent node will send a NodeReport node report message to the upper node, and the upper node that receives this information will use the ID of the newly added node contained in the NodeReport message, the corresponding level, and its The ID (parentID) of the parent node is used to update the routing subtable maintained by itself until the root node at the top layer completes the updating of the routing table. As shown in FIG. 2 , node 5 receives the application success message sent back by node 3 and accesses the network. After sending the ReJoinIn message, node 3 will update its own routing table and send a NodeReport message to its parent node (node 1). Then node 1 inserts the information of the newly accessed node 5 after the entry of node 3 in the routing table according to this message.

Step 4: After the child node sends the JoinIn message, it enters the stage of waiting for the response from the parent node. If the parent node's application success feedback is received, indicating that the connection is bidirectionally reliable and the join is successful, then the node takes this potential parent node as the parent node in the uplink path and forwards the BroadForNet broadcast to search for other nearby nodes . If the feedback from the potential parent node is not received (or the joining failure information is received), the node returns to step 2 and continues to enter the state of waiting to access the network. It can be seen from Figure 2 that the JoinIn message sent by node 6 cannot be received by node 3, so node 6 will return to the state of waiting for access, and successfully access the network after receiving the BroadForNet broadcast from node 4, see image 3.

It can be seen from FIG. 4 that each node records all members and topology information of the subtree with it as the root node, and can realize mutual communication among all members in the subtree. The routing table maintained by the lower nodes is a subset of the table maintained by the upper nodes. For example, if node 5 wants to communicate with node 7, node 5 will first search the routing subtree maintained by itself, and if node 7 is not found, it will send a data packet containing the destination node ID to its parent node. Uplink transmission is carried out until reaching node 1, and destination node 7 appears in the routing tree maintained by node 1, then downlink transmission is started, and data is forwarded to node 4 containing the destination node in the subtree in the next level. Finally, the data packet is sent to the destination node 7 through the node 4 .

Routing table maintenance in case of node reconnection:

In the actual network construction process, the situation shown in Figure 5 may occur, that is, due to some uncertain factors, such as the external environment or multiple nodes sending data at the same time, resulting in data packet collision, reducing the impact of the transmission range, etc., resulting in Node 3 has received the message that node 6 joins the network, but node 6 cannot receive the return message ReJoinIn from node 3. At this time, node 6 will continue to wait for the broadcast from other nodes to access the network, but node 3 thinks that node 6 has received and successfully joined the network, which shows that the Ack provided in TinyOs is not reliable. Then node 3 will send a NodeReport message to the upper network to report the joining of the new node. In fact, when node 4 sends out the BroadForNet broadcast, node 6, which is waiting, successfully accesses the network through node 4, and node 4 reports the status of its child nodes to the upper node. At this time, there will be repeated node 6 in node 1, which will cause confusion during routing selection.

By introducing the Seq mechanism, the occurrence of such problems in actual situations can be well avoided. As shown in Figure 6, after node 6 fails to try to use node 3 as its parent node, the internal Seq will increase, and report its Seq when establishing a parent-child relationship with node 4, and node 4 will add the newly added node 6's Seq is also reported at the same time. In this way, when there is a duplicate node ID in the routing table of node 1, the node will update the routing table according to the size of Seq, delete the entire routing subtree with the original node 6 as the root node in the table, and create Insert node 6 at position. In this example, only one record of node 6 needs to be deleted. Then send a NodeDelete message to all upper nodes on the uplink path of the old node 6 (only node 3 in this example) (in order to avoid multiple upper nodes from repeatedly sending NodeDelete messages, only the node that includes the duplicate node 6 in the subtree is the most The node in the lower layer sends this message downward. In this example, it is node 1. If there are other nodes in the upper layer of node 1, although these nodes will also contain duplicate node 6, they will only update their own routes Table, without sending NodeDelete message downward. NodeDelete message will be sent downward all the time, each node that receives this message deletes the routing record of the corresponding node, and forwards it downward until it reaches the parent node of node 6), update Delete the record of node 6 in its routing table. Because of transmission delays and artificial delays in the network to avoid message collisions, etc., it is not reliable for upper-layer nodes to judge the newness of the path according to the time sequence of receiving NodeReports, that is, the NodeReport message sent by node 6 to node 1 through node 3 It may be later than the arrival time of the NodeReport message sent by node 4 to node 1. Therefore, the introduction of the Seq mechanism ensures the effective maintenance of the routing table in the case of node re-access.

Dynamic organization of the topology and updating of the routing table in case of transmission failure:

Uplink transmission:

As shown in Figure 7(a), node 8 wants to transmit data to node 1, and the transmission fails during the uplink transmission of the data (the number of retransmissions exceeds the set threshold), then node 6 thinks that node 4 may have exceeded The transmission range may have expired. At this time, node 6 will initiate a BroadForParent broadcast to search for a new access point. It can be seen from the figure that the broadcast range covers five nodes 3, 4, 5, 7, and 8, among which node 4 may have failed and cannot communicate, so it is not considered. The BroadForParent broadcast packet will contain the ID of the node, the ID of its parent node, and the Level of the node. Node 7 does not send a ReBroadForPa response because it finds that Node 6 has a common graph node with it. And node 8 finds that node 6 is its parent node, so it does not respond. It can be seen that the nodes on another subtree other than node 4 meet the requirements and give feedback. For node 6, it will receive feedback from each node within a certain time slot, and preferentially select the node with a smaller number of Levels to reduce the number of hops to reach the sink node. At the same time, node 6 will also determine whether the node applying for access is in its own subtree, so as to avoid errors in data cyclic transmission. In this example, it can be seen that node 6 has received the feedback from node 3 and node 5, and is the first to try to reconnect to the network from node 3, but node 3 cannot receive the application message sent by it. Then node 6 tries to access node 5 again, and the application is successful. At this time, for node 5, it needs to judge whether it has enough storage space to accommodate the subtree of node 6. If the conditions permit, it will feedback the message of successful application and send a NodeReport message to the upper layer to update the route of the upper node table, join the path to node 6. At the same time, node 6 will send a NodeUpdate message to the rooted subtree to update the Level information of node 8 . It can be seen that the Level of node 8 has changed from the original Level 3 to Level 4 at this time. In addition, node 6 will also send a NodeReport message to its parent node (node 5) to inform it of the topology information of the subtree it maintains, and update the upper-level nodes sequentially through node 5. When node 1 receives the NodeReport message from node 6 to reconnect, it will delete and update the information of the subtree headed by node 6 in the original routing table, and finally inform the original parent node of node 6 through the NodeDelete message (Node 4) Delete routing information that has expired. Thus, the process of node topology reorganization in the uplink path transmission is completed. The reorganized topology is shown in Fig. 7(b).

As shown in Figure 8(a), if node 8 also wants to realize the uplink data transmission to node 1, but due to the accident of node 4, all routing information is lost (at this time, node 4 has not joined the network at all, and does not know its information of the parent node and all child nodes), but cannot pass data. At this time, node 4 will return the error message of RouteTableError to node 6 that sent the data. At this time, node 6 will send out a BroadForParent broadcast as described in the example in FIG. 7, so as to reconnect to the network. Similarly, node 6 received feedback information from nodes 3 and 5, and successfully connected to node 3 (because it is smaller than node 5 Level). Since the Level remains unchanged after node 6 reconnects, there is no need to send NodeUpdate information to update its Level information. The reorganized topology is shown in Fig. 8(b). It can be predicted that because node 4 lost the route information, when its remaining child nodes, such as node 7, need to transmit data, they will also receive the feedback information of RouteTableError from node 4, so as to reconnect to the network through other nodes.

Downstream transmission:

As shown in Figure 9(a), node 5 wants to transmit data to node 8, but a transmission failure occurs during the transmission from node 1 to node 4. At this time, node 1 thinks that node 4 is no longer able to communicate, and deletes the subtree rooted at node 4, and sends out a BroadForChild broadcast to find other nodes that may know the path to node 8, in this case, node 6 (node 6 It may enter the Radio transmission range of node 1 due to the position change). At this time, each node that receives the broadcast will search the routing table it maintains, and only if the routing table contains the information of node 6, it will send a SubtreeJoinIn message to reply. And because it is downlink transmission at this time, only nodes whose Level is greater than node 1 can respond. If node 1 still has a parent node, the parent node will not respond to SubtreeJoinIn. Node 1 will send a ReSubJoinIn confirmation message after receiving node 6's request to join the entire subtree headed by it. After receiving the confirmation message, node 6 changes the ID of its parent node (that is, node 1 as its parent node) and sends a NodeReport message to it to update the routing table of the upper node. Then it will send a NodeUpdate message to its child nodes to update its Level information. In this way, with the reconnection of node 6, the data transmission path from node 5 to node 8 that was originally disconnected due to the problem of node 4 is repaired, and the new network topology is shown in Figure 9(b).

If there is a situation that node 4 loses the road information due to an unexpected situation. Node 4 will return a RouteTableError message after receiving the Data transmission request. At this time, node 1 will send a BroadForChild broadcast to repair the downlink path as mentioned above. See Figure 10.

The update of the routing table when a new node accesses the network:

The situation of a new node joining the network is similar to the processing mechanism after a problem occurs in the uplink transmission. As shown in FIG. 11 , the new node 9 needs to access the network when triggered by data to be transmitted. At this time, node 9 will initiate a BroadForParent broadcast to find nearby access points. If there are multiple nodes responding, the node with a lower Level is selected for access. In this example, node 7 with a Level of 2 is selected, and a JoinIn message is sent to request access. After receiving the ReJoinIn message from node 7, it formally joins the network and starts to transmit data. After receiving the NodeReport message, the upper layer node adds the routing information of the new node 9 in its routing table.

Claims (8)

1. one kind is applicable to the dynamic self-organization method for routing by different level of wireless sensor network, it is characterized in that: based on wireless sensor network, the tree-shaped network topology structure by different level of multi-fork is adopted to carry out networking, each node in whole network safeguards a routing table, in order to record with the topological structure of this node subtree that is root, and the topology of tree structure is mapped as one-dimensional linear list according to the preorder traversal of multiway tree, so that calculating and administering and maintaining in the limited node of storage capacity, by inserting sequence number, routing table is effectively upgraded in the access application of node, only when there is the link that data cannot be transmitted, just carrying out topology restructuring by re-establishing link, when being included in transmitting uplink data failure, being set by frequency of failure threshold value, judge whether again to find father node, or feedback Error information is to aggregation node prompting abnormal information, when being included in downlink data transmission failure, set by frequency of failure threshold value, judge whether that broadcast is found, and repair failing path, or feedback Error information repairs downlink path, when new node supplements access network, search adjacent node by broadcast, select father node to set up set membership as after the access point of network, and lastest imformation is reported to upper strata.

2. a kind of dynamic self-organization method for routing being by different level applicable to wireless sensor network according to claim 1, it is characterized in that: based on wireless sensor network, adopt the tree-shaped network topology structure by different level of multi-fork, in a network node motion or inefficacy and the situation causing path failure data to transmit time, for network provides the method for a set of reorganization topological structure, realize the dynamic conditioning of network topology structure.

3. a kind of dynamic self-organization method for routing being by different level applicable to wireless sensor network according to claim 2, it is characterized in that: at the beginning of network is set up, the broadcast of setting up network is initiated by some specified nodes, the adjacent node receiving this broadcast will send time node of broadcast as potential father node, and the request becoming its child node is sent to father node, represent and add successfully after feedback receiving father node, continuation is sent networking broadcast to lower floor, search next node layer, by that analogy, until all nodes in region are all capped, complete networking.

4. a kind of dynamic self-organization method for routing being by different level applicable to wireless sensor network according to claim 1, it is characterized in that: each node newly adding network is receiving after father node confirms its access network, to upwards be reported the information of new access node from level to level by clean culture, the node receiving this message is by the whole tree-like subnet that is root according to the location updating of this node access point with it.

5. a kind of dynamic self-organization method for routing being by different level applicable to wireless sensor network according to claim 1, it is characterized in that: in the access application of node, insert sequence number routing table is effectively upgraded, namely sequence number is utilized to carry out maintaining routing list, as long as each node sends the application once accessed, the sequence number of its inside will add up; When connecting after node layer receives the information upgrading routing table, will judge to need the sequence number of node of renewal whether than the renewal in former routing table; If the subtree in former routing table headed by this node is then deleted in new path, refresh routing table according to the information upgraded.

6. a kind of dynamic self-organization method for routing being by different level applicable to wireless sensor network according to claim 1, it is characterized in that: during transmitting uplink data failure topology restructuring, if failure cause is next-hop node and father node, shift out transmission range or inefficacy, thus cause data to transmit, if then bust this number of times has exceeded the threshold value of setting, then find new father node by broadcast, re-accessing network; If failure cause is next-hop node owing to restart or other reasons lost routing iinformation, and data transmission cannot be carried out, then can upper hop node feeding back Error information when receiving data and needing to forward, now, the upper hop node receiving Error information also will look for new father node by broadcast, if each node in upstream transmission line does not all find the path arriving destination node in its routing table safeguarded, then the final packet forwarded will arrive at aggregation node, and produces abnormal information.

7. a kind of dynamic self-organization method for routing being by different level applicable to wireless sensor network according to claim 1, it is characterized in that: during downlink data transmission failure topology restructuring, if failure cause is that data cannot allow the next-hop node i.e. a certain child node of this node receive, now, as long as the number of times of bust this exceedes the threshold value of setting, then initiation broadcast is found by this node, as long as store the node arriving destination node path will respond, this node will select level at a distance of nearest node as child node, thus repaired the path of having lost efficacy, if next-hop node is exactly destination node, and now destination node is lost, data cannot be transmitted, then abnormal information is beamed back aggregation node, if failure cause is that next-hop node and the appearance of non-destination node lost routing information extremely, then now will feed back Error information, then this node will find next-hop node by broadcast after receiving Error information, repair downlink path.

8. a kind of dynamic self-organization method for routing being by different level applicable to wireless sensor network according to claim 1, it is characterized in that: for sending sensing data to aggregation node and not yet adding network, the new node that there is not any routing iinformation searches the access point of adjacent node as network by broadcast, after the reply obtaining adjacent node, select a certain node as access point, and set up set membership, the father node having new child node to access will be reported the information of new child node to upper strata and upwards upgrade successively, complete new node and supplement access network process.