CN102196461A - Evaluation method for importance of sensor network node - Google Patents

Abstract

The invention discloses an evaluation method for the importance of a sensor network node, and relates to the technical field of wireless sensor network communication. The evaluation method comprises the following steps of: S1, establishing an information transfer routing table of a sensor network, and confirming a topological structure of the sensor network; S2, collecting energy information of all nodes in the sensor network according to the routing table; S3, judging whether a node with exhausted energy exists, and going to step S4 if the node with exhausted energy exists, or calculating the importance of each node according to the topological structure contribution and remaining energy of each node and going to step S2 if the node with exhausted energy does not exist; and S4, calculating operation times of the sensor network as a life cycle of the sensor network. When the evaluation method is adopted, the importance of the sensor network node can be calculated more accurately, and therefore, the destruction resistance of the sensor network can be improved through protecting the importance of the node.

Description

The sensor network nodes importance evaluation method

Technical field

The present invention relates to the radio sensing network communication technical field, particularly a kind of sensor network nodes importance evaluation method.

Background technology

Sensor network is the comprehensive intelligent information system that integrates information gathering, message transmission, information processing, it is a focus of current information area research and exploitation, the collection that can realize data quantizes, handles and merge and the transmission application, can be used for military and civilian fields such as military surveillance, environmental monitoring, medical monitoring, space exploration, urban traffic control, warehousing management.In the practical application of sensor network, generally all need to dispose a large amount of sensor nodes, because node often is operated in the rugged environment, and adopt the battery of finite energy that energy is provided usually, depleted of energy or be subjected to nature and destroy and the situation that part of nodes lost efficacy occurs so sensor network is easy to occur; In addition, also can cause disintegrating of whole network directly or indirectly to the purposive destruction of sensor network.By the evaluation of node importance, can in network in large scale, baroque, accurately and fast find the important node in the network, thus can be by the protection of important node being improved the survivability of network.

The importance evaluation of network node at present mainly contains the interior node importance sort algorithm of social network analysis field and the node importance evaluation method in systematic science field.The former is based on " importance is equivalent to conspicuousness ", and promptly node importance is equivalent to this node makes it have with being connected of other nodes conspicuousness.The latter is based on " destructiveness is equivalent to importance ", by node metric or the deleted back of set of node the destructiveness of network-in-dialing defined promptly that it is important.The importance that these research major parts all are based on index such as node degree, tightness, characteristic vector, Jie's number or index of correlation are improved evaluation node.What most of research institutes adopted all is the single evaluation index, so there are problems such as uncertain and not comprehensive in evaluation effect.Particularly in present research, the research at the evaluation of sensor network nodes importance does not almost have specially.Because sensor network is operated in the network environment of a high complexity, how improves the reliability of sensor network under complex network environment and become the subject matter of being badly in need of solution in the sensor network research.Therefore, the important evaluation study of sensor network nodes had important and practical meanings and using value.Be necessary to carry out deep discussion and research with regard to how setting up rational sensor network nodes importance evaluation index.

Open on February 16th, 2011 by China national Department of Intellectual Property, publication number is the patent application " sort method of node importance in the network " of CN101976245A, discloses the sort method of node importance in a kind of network.This method adds a background node in directed networks, and the background node is all set up two-way linking with each node in the directed networks; Initial time is given the resource of each node one unit, contains random walk in the network of the node of having powerful connections at this then, carries out resource allocation, up to reaching stable state; Number of resources during with stable state on the background node adds that the number of resources sum that obtains from the background node is the mark of this node importance; With node sequencing, it is important more to come this node of top expression according to importance scores together order from high to low.This method can be used for the ordering of node importance in the network, as the ordering of Web page importance.

The method of above node importance evaluation is conceived to different emphasis respectively and pros and cons to some extent, is mainly reflected in:

(1) existing node importance evaluation method is not considered problems such as residue energy of node, and its evaluation method is not suitable for sensor network;

(2) existing node importance evaluation method is mostly taked single evaluation of indexes method, and there is uncertain and incomplete problem in evaluation effect.

Summary of the invention

(1) technical problem that will solve

How more accurately the technical problem to be solved in the present invention is: the importance of the node of estimated sensor network.

(2) technical scheme

For solving the problems of the technologies described above, the invention provides a kind of sensor network nodes importance evaluation method, may further comprise the steps:

S1: the information of setting up sensor network is transmitted routing table, determines the topological structure of sensor network;

S2:, collect the energy information of all nodes in the described sensor network according to routing table;

S3: judge whether the depleted of energy of node, then go to step S4 if having; If do not have, then calculate the importance of each node, and go to step S2 according to the topological structure contribution and the dump energy of each node;

S4: calculate the life cycle of the number of run of described sensor network as described sensor network.

Wherein, described step S1 specifically comprises:

Aggregation node adopts the mode of inundation to send data to all nodes, the notice node begins to collect data, after each node is received the data that aggregation node sends, send response message to aggregation node, response message comprises: residue energy of node and the packet size that will send;

Aggregation node receives after the response message, makes up the dynamic routing tree according to residue energy of node;

Aggregation node passes through the mode of inundation with routing tree information all node broadcasts in sensor network;

Each node is set up the routing table that information is transmitted according to the routing tree information of receiving, determines network topology structure, carries out transfer of data.

Wherein, the mode of the importance of each node of calculating is specially among the described step S3:

$M\left(i\right)=k_{1}C\left(i\right)+k_2(1-\frac{\mathrm{Re}\left(i\right)}{E})$

Wherein, M (i) is the importance of node i, and C (i) is:

$C\left(i\right)=\frac{\underset{j<k}{\mathrm{\&Sigma;}}{g}_{\mathrm{jk}}\left(i\right)/g_{\mathrm{jk}}}{(N-1)(N-2)/2}$

Node i is all passed through in the expression arbitrarily shortest path between other node, and then node i is to the sensor network topological structural contribution, wherein, and g _JkShortest path number between expression node j and the node k, g _Jk(i) the shortest path number of process node i between expression node j and the node k, N is the node sum in the described sensor network;

Re (i) is the dump energy of node i, and E is the node i primary power, k ₁Be topology contribution regulatory factor, k ₂Be the dump energy regulatory factor, and k ₁+ k ₂=1,0＜k ₁＜1,0＜k ₂＜1.

Wherein, among the described step S3, calculated after the importance of all nodes at every turn, also comprised step: the importance evaluation index when calculating described sensor network and being subjected to hitting at random:

$M=\underset{i=1}{\overset{i=N}{\mathrm{\&Sigma;}}}M\left(i\right)\frac{1}{N}.$

Wherein, among the described step S3, calculated after the importance of all nodes at every turn, also comprised step: the importance evaluation index when calculating described sensor network and being subjected to premeditated the strike:

$M^{\&prime;}=\underset{i=1}{\overset{i=N}{\mathrm{\&Sigma;}}}{(M\left(i\right)-\underset{i=1}{\overset{i=N}{\mathrm{\&Sigma;}}}M\left(i\right)\frac{1}{N})}^2.$

Wherein, also comprise step: dispose super node to prolong the life cycle of described sensor network near P the node before being arranged in by the importance values that calculates is descending, described super node be energy more than or equal to 3000J, the node radio communication radius is more than or equal to the node of 500m.

(3) beneficial effect

The present invention can calculate the importance of sensor network nodes by the topological structure contribution and the dump energy of each node, thereby can improve the survivability of sensor network by the protection to the importance node.

Description of drawings

Fig. 1 is a kind of sensor network nodes importance evaluation method flow chart of the embodiment of the invention;

Fig. 2 is that node is contributed schematic diagram to network topology structure;

Fig. 3 is the residue energy of node distribution schematic diagram;

Fig. 4 is a network-critical node distribution schematic diagram;

Fig. 5 be in network special add super node, at random add super node, hit important node and premeditated comparative graph of hitting important node situation lower network life cycle at random.

Embodiment

Below in conjunction with drawings and Examples, the specific embodiment of the present invention is described in further detail.Following examples are used to illustrate the present invention, but are not used for limiting the scope of the invention.

As shown in Figure 1, sensor network nodes importance evaluation method of the present invention comprises:

Step S101 sets up the information of sensor network and transmits routing table, determines the topological structure of sensor network.Energy constraint is the greatest problem that sensor network exists, in order effectively to save node energy, prevent from frequent use same paths transmission data and cause that node energy consumes too fast and premature failure on this path, need a kind of dynamic routing algorithm that can weigh node energy and network topology structure to come the network energy that is consumed in the equalization data transmission course, to prolong the life span of sensor network.Therefore, present embodiment takes into full account network energy consumption and residue energy of node, makes up the dynamic routing tree by dijkstra's algorithm, and concrete mode is as follows:

Aggregation node adopts the mode of inundation to send data to all nodes, the notice node begins to collect data, after each node is received the data that aggregation node sends, send response message to aggregation node, response message comprises residue energy of node and the packet size that will send.Aggregation node is a kind of special joint in the sensor network, main being responsible for collected the information (comprising above-mentioned residue energy of node and the packet size that will send) that other sensor node collection is come, and the information of gathering is sent to the Internet, satellite or other receiving system.

Aggregation node receives after the response message, makes up the dynamic routing tree according to residue energy of node.

Aggregation node passes through the mode of inundation with routing tree information all node broadcasts in network.

Each node is set up the routing table that information is transmitted according to the routing tree information of receiving, determines network topology structure, carries out transfer of data.

Step S102, according to routing table, the energy information of all nodes in the aggregation node collecting sensor network.Because sensor network is in running, the energy of node is in continuous variation, and the energy of different nodes is also different.Therefore, the energy information of at every turn collecting is also different.

Step S103 judges whether the depleted of energy of node, then goes to step S105 if having; If do not have, then go to step S104.

Step S104 calculates the importance of each node according to the mode that topological structure is contributed and dump energy combines of each node, and goes to step S102.Wherein, the concrete account form of the importance M of each node (i) is as follows:

$M\left(i\right)=k_{1}C\left(i\right)+k_2(1-\frac{\mathrm{Re}\left(i\right)}{E})$

Wherein, C (i) is:

$C\left(i\right)=\frac{\underset{j<k}{\mathrm{\&Sigma;}}{g}_{\mathrm{jk}}\left(i\right)/g_{\mathrm{jk}}}{(N-1)(N-2)/2}$

Node i is all passed through in the expression arbitrarily shortest path between other node, and then node i is to the sensor network topological structural contribution, wherein, and g _JkShortest path number between expression node j and the node k, g _Jk(i) the shortest path number of process node i between expression node j and the node k, C (i) has portrayed the influence power of the node in the network for information flow, reflected that this node provides the ability of short available route in finishing the network service task, can be used to determine the heavy network node of information loads.N is the node sum in the described sensor network.

Re (i) is the dump energy of node i, and E is the node primary power, k ₁Be topology contribution regulatory factor, k ₂Be the dump energy regulatory factor, and k ₁+ k ₂=1,0＜k ₁＜1,0＜k ₂＜1, in the actual evaluation process, can select suitable k according to actual conditions ₁And k ₂

k ₁C (i) has embodied the evaluation of node location to node importance, k ₁The contribution of the big more expression node i of C (i) topological structure is big more, i.e. node i residing position in network important more (a lot of internodal beelines are all passed through node i).

Embodied the evaluation of dump energy to node importance,

Big more, node i is important more, and promptly dump energy Re (i) is more little, and node i is important more.Can regulate k as required in the practice ₁And k ₂Size determine the importance of node i.

Step S105 calculates the life cycle of the number of run of described sensor network as described sensor network, promptly when the depleted of energy of node occurring for the first time in the sensor network, thinks that then the life cycle of sensor network finishes.

In step S104, calculated after the importance of all nodes at every turn, also comprise step: the importance evaluation index when calculating described sensor network and being subjected to hitting at random:

$M=\underset{i=1}{\overset{i=N}{\mathrm{\&Sigma;}}}M\left(i\right)\frac{1}{N}.$

Wherein, among the described step S3, calculated after the importance of all nodes at every turn, also comprised step: the importance evaluation index when calculating described sensor network and being subjected to premeditated the strike:

$M^{\&prime;}=\underset{i=1}{\overset{i=N}{\mathrm{\&Sigma;}}}{(M\left(i\right)-\underset{i=1}{\overset{i=N}{\mathrm{\&Sigma;}}}M\left(i\right)\frac{1}{N})}^2.$

Obtain after the importance of node, just can adjust node according to importance, increase super node to prolong the life cycle of described sensor network by near the descending deployment that is arranged in preceding P node of the importance values that calculates, that is to say and near important node, dispose super node, actual is exactly a kind of backup, when important node lost efficacy, super node was started working.Described super node be energy more than or equal to 3000J, the node radio communication radius is more than or equal to the node of 500m, and is all bigger than the energy and the communication radius of general sensor node.

Method of the present invention is tested, and experiment parameter is as shown in table 1:

The parameter of table 1 experiment usefulness

Parameter name	Parameter setting values
		The target area	1000m×1000m
Interstitial content	500
		The node maximum launch range	200m
The node primary power	1000J
		Node receives or sends the energy consumption of every Bit data	50nJ/bit
Amplifier sends the energy consumption of every Bit data	100pJ/bit/m 2
		The path loss coefficient	2
Node is issued the data volume of aggregation node at every turn	1Mb
		Simulation times
	100

Emulation 1: be to estimate the validity of node importance evaluation index of the present invention, the routing algorithm of step S101 is carried out emulation.Can obtain node to the relation between topological structure contribution and the dump energy, as shown in Figures 2 and 3 by emulation.Wherein, Fig. 2 is the schematic diagram that node is contributed topological structure in certain moment network, the small part node is bigger to the contribution of network topology structure from scheme as can be known network, mainly be because these nodes are in key position on the shortest path of route, need often to transmit data, this estimates the k of overall target M (i) at node importance ₁C (i) part embodies to some extent; Fig. 3 is a residue energy of node distribution schematic diagram in certain moment network, contribute big node as can be known from Fig. 3 in topological structure, owing to often transmit data, energy consuming ratio is very fast, therefore the dump energy of these nodes is relatively low, and this estimates overall target M's (i) at node importance

Part embodies to some extent.Comparison diagram 2 and Fig. 3 as can be seen, the topological percentage contribution of node and its dump energy roughly are inversely proportional in the whole network, this situation with the sensor network practical application conforms to.

Emulation 2: according to relation and the data of node among Fig. 2 and Fig. 3, estimate overall target, get k in conjunction with node importance of the present invention to topological structure contribution and dump energy ₁=0.5, k ₂=0.5, the distribution situation that can obtain important node in the network as shown in Figure 4.With label is that 5 and 61 node is an example, and the contribution of node 5 and 61 pairs of topologys of node is respectively 0.85 and 0.84 as can be seen from Figure 2, and the dump energy of node 5 and node 61 is respectively 50J and 40J as can be seen from Figure 3, according to the node importance evaluation index $M\left(i\right)=k_{1}C\left(i\right)+k_2(1-\frac{\mathrm{Re}\left(i\right)}{E}),$ As can be known $M\left(5\right)=0.5\&times;0.85+0.5\&times;(1-\frac{50}{1000})=0.9,$ $M\left(61\right)=0.5\&times;0.84+0.5\&times;(1-\frac{40}{1000})=0.9,$ Therefore the node importance of node 5 and node 61 is 0.9.As can be seen from Figure 4, in preceding 100 nodes, label is that 5,61 nodes such as (can find out also that from figure importance is 0.9) belong to the important node in the network.Therefore, the node that importance is bigger is protected, can be improved the survivability of sensor network, prolong the life cycle of sensor network, as: strengthen the primary power of nodes such as above-mentioned 5,61, or dispose super node in its vicinity.

Emulation 3: hit at random and the validity of node importance evaluation index M and M ' when deliberate strike for further analysis,, the survivability of network is analyzed according to network-critical node distribution situation among Fig. 4.During emulation, at the important node in the network, add specially super node (node energy 3000J, node radio communication radius are 500m), at random add super node, hit important node and the premeditated important node of hitting at random.Situation of change to above-mentioned 4 kinds of situation lower sensor network lifecycles is analyzed.As can be seen from Figure 5, the life cycle of network has greatly improved after adding super node near the important node, and the network survivability strengthens; The life cycle of network has decline by a relatively large margin after the premeditated strike important node, and the network survivability reduces; The life cycle that adds super node at random and hit the important node network at random changes not obvious.Above-mentioned simulation result shows important node in the network is protected to improve the importance of network survivability, verified that further node importance of the present invention estimates the reasonability and the validity of overall target.

Above execution mode only is used to illustrate the present invention; and be not limitation of the present invention; the those of ordinary skill in relevant technologies field; under the situation that does not break away from the spirit and scope of the present invention; can also make various variations and modification; therefore all technical schemes that are equal to also belong to category of the present invention, and scope of patent protection of the present invention should be defined by the claims.

Claims (6)

1. a sensor network nodes importance evaluation method is characterized in that, may further comprise the steps:

S1: the information of setting up sensor network is transmitted routing table, determines the topological structure of sensor network;

S2:, collect the energy information of all nodes in the described sensor network according to routing table;

S3: judge whether the depleted of energy of node, then go to step S4 if having; If do not have, then calculate the importance of each node, and go to step S2 according to the topological structure contribution and the dump energy of each node;

S4: calculate the life cycle of the number of run of described sensor network as described sensor network.

2. sensor network nodes importance evaluation method as claimed in claim 1 is characterized in that, described step S1 specifically comprises:

Aggregation node adopts the mode of inundation to send data to all nodes, the notice node begins to collect data, after each node is received the data that aggregation node sends, send response message to aggregation node, response message comprises: residue energy of node and the packet size that will send;

Aggregation node receives after the response message, makes up the dynamic routing tree according to residue energy of node;

Aggregation node passes through the mode of inundation with routing tree information all node broadcasts in sensor network;

Each node is set up the routing table that information is transmitted according to the routing tree information of receiving, determines network topology structure, carries out transfer of data.

3. sensor network nodes importance evaluation method as claimed in claim 1 is characterized in that, the mode of calculating the importance of each node among the described step S3 is specially:

$M\left(i\right)=k_{1}C\left(i\right)+k_2(1-\frac{\mathrm{Re}\left(i\right)}{E})$

Wherein, M (i) is the importance of node i, and C (i) is:

$C\left(i\right)=\frac{\underset{j<k}{\mathrm{\&Sigma;}}{g}_{\mathrm{jk}}\left(i\right)/g_{\mathrm{jk}}}{(N-1)(N-2)/2}$

Node i is all passed through in the expression arbitrarily shortest path between other node, and then node i is to the sensor network topological structural contribution, wherein, and g _JkShortest path number between expression node j and the node k, g _Jk(i) the shortest path number of process node i between expression node j and the node k, N is the node sum in the described sensor network;

Re (i) is the dump energy of node i, and E is the node i primary power, k ₁Be topology contribution regulatory factor, k ₂Be the dump energy regulatory factor, and k ₁+ k ₂=1,0＜k ₁＜1,0＜k ₂＜1.

4. sensor network nodes importance evaluation method as claimed in claim 3, it is characterized in that, among the described step S3, calculated after the importance of all nodes at every turn, also comprised step: the importance evaluation index when calculating described sensor network and being subjected to hitting at random:

$M=\underset{i=1}{\overset{i=N}{\mathrm{\&Sigma;}}}M\left(i\right)\frac{1}{N}.$

5. sensor network nodes importance evaluation method as claimed in claim 3, it is characterized in that, among the described step S3, calculated after the importance of all nodes at every turn, also comprised step: the importance evaluation index when calculating described sensor network and being subjected to premeditated the strike:

$M^{\&prime;}=\underset{i=1}{\overset{i=N}{\mathrm{\&Sigma;}}}{(M\left(i\right)-\underset{i=1}{\overset{i=N}{\mathrm{\&Sigma;}}}M\left(i\right)\frac{1}{N})}^2.$

6. as each described sensor network nodes importance evaluation method of claim 1～5, it is characterized in that, also comprise step: dispose super node to prolong the life cycle of described sensor network near P the node before being arranged in by the importance values that calculates is descending, described super node be energy more than or equal to 3000J, the node radio communication radius is more than or equal to the node of 500m.

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