CN102196461B - 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

Evaluation method for importance of sensor network node

Technical field

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

Background technology

Sensor network is the comprehensive intelligent information system that integrates information gathering, communication, information processing, it is a focus of current information area research and exploitation, the collection that can realize data quantizes, process and merge and transmission is used, and can be used for the military and civilian such as military surveillance, environmental monitoring, medical monitoring, space exploration, urban traffic control, warehousing management field.In the practical application of sensor network, generally all need to dispose a large amount of sensor nodes, because node often is operated in rugged environment, and usually adopt the battery of finite energy that energy is provided, the depleted of energy or be subject 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 directly or indirectly disintegrating of whole network to the purposive destruction of sensor network.By the evaluation of node importance, can be in network in large scale, baroque accurate the and fast important node in discovering network, thereby can be by the protection of important node being improved the survivability of network.

At present the Assessment of Important of network node mainly contains node importance sort algorithm in the 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 namely 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 ", defines by node metric or the deleted rear destructiveness to network-in-dialing of set of node namely that it is important.The importance that these research major parts all are based on the index such as node degree, tightness, characteristic vector, betweenness or index of correlation are improved evaluation node.What most of research institutes adopted is all the single evaluation index, so there are the problems such as uncertain and not comprehensive in evaluation effect.Particularly in present research, the research for the sensor network nodes Assessment of Important does not almost have specially.Be operated in due to sensor network in the network environment of a high complexity, how improve the reliability of sensor network under complex network environment and become the subject matter of being badly in need of solution in sensor network research.Therefore, the important evaluation study of sensor network nodes had important practical significance and using value.Be necessary to carry out deep research with regard to how setting up rational sensor network nodes Assessment of Important 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 network " of CN101976245A, discloses a kind of sort method of node importance in network.The method adds a background node in directed networks, and the background node is set up two-way linking with each node in directed networks; Initial time is given the resource of each node one unit, then contains random walk in the network of the node of having powerful connections at this, carries out resource and distributes, until reach 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, come this node of top expression more important according to importance scores together order from high to low.The method can be used for the sequence of node importance in network, as the sequence of Web page importance.

Above node importance Appraising Methods is conceived to respectively different emphasis and pros and cons to some extent, is mainly reflected in:

(1) existing node importance evaluation method is not considered the 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 the evaluation method of single index, and there is uncertain and incomplete problem in evaluation effect.

Summary of the invention

The technical problem that (one) 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 evaluation method for importance of sensor network node, comprise the following steps:

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

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

S3: judge whether the depleted of energy of node, go to step S4 if having; If no, calculate the importance of each node according to topological structure contribution and the dump energy of each node, and go to step S2;

S4: calculate the number of run of described sensor network as the life cycle of 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 data package size that will send;

After aggregation node receives response message, build the dynamic routing tree according to residue energy of node;

The mode of aggregation node by inundation is with routing tree information all node broadcasts in the sensor network;

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

Wherein, in described step S3, the mode of the importance of each node of calculating 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 node i is to the sensor network topological structural contribution, wherein, and g _jkShortest path number between expression node j and node k, g _jk(i) the shortest path number of process node i between expression node j and node k, N are the node sum in described sensor network;

Re (i) is the dump energy of node i, and E is the node i primary power, k ₁Be topological structure 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, in described step S3, after having calculated the importance of all nodes, also comprise step: the Assessment of Important index when calculating described sensor network and being subject to hitting at random at every turn:

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

Wherein, in described step S3, after having calculated the importance of all nodes, also comprise step: the Assessment of Important index when calculating described sensor network and being subject to premeditated the strike at every turn:

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

Wherein, also comprise step: by disposing super node near a node of the descending P of being arranged in front of the importance values that calculates to extend the life cycle of described sensor network, 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 topological structure contribution and the dump energy of each node, thereby can improve by the protection to the importance node survivability of sensor network.

Description of drawings

Fig. 1 is a kind of evaluation method for importance of sensor network node flow chart of the embodiment of the present 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 network-critical node distribution schematic diagram;

Fig. 5 be add specially in network 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 for explanation the present invention, but are not used for limiting the scope of the invention.

As shown in Figure 1, evaluation method for importance of sensor network node 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 frequently using same path transmission data and cause on this path node energy to consume too fast and premature failure, need a kind of dynamic routing algorithm that can weigh node energy and network topology structure to come the network energy that consumes in the equalization data transmitting procedure, to extend the life span of sensor network.Therefore, the present embodiment takes into full account network energy consumption and residue energy of node, builds 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 data package size that will send.Aggregation node is a kind of special joint in sensor network, main being responsible for collected the information (comprising above-mentioned residue energy of node and the data package size that will send) that other sensor node collection is come, and the information that gathers is sent to the Internet, satellite or other receiving system.

After aggregation node receives response message, build the dynamic routing tree according to residue energy of node.

The mode of aggregation node by inundation is with routing tree information all node broadcasts in the network.

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

Step S102, according to routing table, the energy information of all nodes in aggregation node collecting sensor network.In running, the energy of node is in continuous variation due to sensor network, 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, goes to step S105 if having; If no, 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 node i is to the sensor network topological structural contribution, wherein, and g _jkShortest path number between expression node j and node k, g _jk(i) the shortest path number of process node i between expression node j and 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 completing the network service task, can be used to determine the heavy network node of information loads.N is the node sum in described sensor network.

Re (i) is the dump energy of node i, and E is the node primary power, k ₁Be topological structure 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 larger expression node i of C (i) topological structure is larger, i.e. node i residing position in network more important (a lot of internodal beelines are all passed through node i).

Embodied the evaluation of dump energy to node importance,

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

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

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

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

Wherein, in described step S3, after having calculated the importance of all nodes, also comprise step: the Assessment of Important index when calculating described sensor network and being subject to premeditated the strike at every turn:

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

After obtaining the importance of node, just can adjust node according to importance, near deployment by a node of the descending P of being arranged in front of the importance values that calculates increases super node to extend the life cycle of described sensor network, that is to say and dispose super node near important 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 larger than 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 use

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 dump energy, as shown in Figures 2 and 3 by emulation.Wherein, Fig. 2 is certain nodes schematic diagram to the topological structure contribution constantly, the small part node is larger to the contribution of network topology structure from scheme as can be known network, mainly because these nodes are in key position on the shortest path of route, need frequent forwarding data, this estimates overall target M(i at node importance) k ₁C (i) part embodies to some extent; Fig. 3 is certain nodes dump energy distribution schematic diagram constantly, contribute as can be known from Fig. 3 large node in topological structure, due to frequent forwarding data, energy consuming ratio is very fast, therefore the dump energy of these nodes is relatively low, and this estimates overall target at node importance Part embodies to some extent.Comparison diagram 2 and Fig. 3 can find out, topological structure percentage contribution and its dump energy of whole nodes roughly are inversely proportional to, and this situation with the sensor network practical application conforms to.

Emulation 2: to topological structure contribution and residual energy the relationship between quantities and data, estimate overall target in conjunction with node importance of the present invention according to node in Fig. 2 and Fig. 3, get k ₁=0.5, k ₂=0.5, can obtain the distribution situation of important node in network as shown in Figure 4.Node take label as 5 and 61 is as 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 front 100 nodes, label is 5,61(can find out also that from figure importance is 0.9) etc. node belong to important node in network.Therefore, the node that importance is larger is protected, can be improved the survivability of sensor network, extend the life cycle of sensor network, as: strengthen the primary power of the nodes such as above-mentioned 5,61, or dispose in its vicinity super node.

Emulation 3: the validity of node Assessment of Important index M and M ' during for the random strike of further analysis and premeditated strike, according to the distribution situation of network-critical node in Fig. 4, the survivability of network is analyzed.During emulation, for the important node in 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 important node, and Survivabilities of Networks strengthens; After premeditated strike important node, the life cycle of network has decline by a relatively large margin, and Survivabilities of Networks reduces; Add at random super node and random life cycle of hitting the important node network to change not obvious.Above-mentioned simulation result shows important node protection in network is improved the importance of Survivabilities of Networks, verified that further node importance of the present invention estimates reasonability and the validity of overall target.

Above execution mode only is used for explanation the present invention; and be not limitation of the present invention; the those of ordinary skill in relevant technologies field; without departing from the spirit and scope of the present invention; can also make a variety of changes 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 (5)

1. an evaluation method for importance of sensor network node, is characterized in that, comprises the following steps:

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

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

S3: judge whether the depleted of energy of node, go to step S4 if having; If no, calculate the importance of each node according to topological structure contribution and the dump energy of each node, and go to step S2; The mode of wherein calculating the importance of each node 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 node i is to the sensor network topological structural contribution, wherein, and g _jkShortest path number between expression node j and node k, g _jk(i) the shortest path number of process node i between expression node j and node k, N are the node sum in described sensor network;

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

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

2. evaluation method for importance of sensor network node 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 data package size that will send;

After aggregation node receives response message, build the dynamic routing tree according to residue energy of node;

The mode of aggregation node by inundation is with routing tree information all node broadcasts in the sensor network;

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

3. evaluation method for importance of sensor network node as claimed in claim 1, it is characterized in that, in described step S3, after having calculated the importance of all nodes, also comprise step: the Assessment of Important index when calculating described sensor network and being subject to hitting at random at every turn:

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

4. evaluation method for importance of sensor network node as claimed in claim 1, it is characterized in that, in described step S3, after having calculated the importance of all nodes, also comprise step: the Assessment of Important index when calculating described sensor network and being subject to premeditated the strike at every turn:

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

5. evaluation method for importance of sensor network node as described in claim 1 ~ 4 any one, it is characterized in that, also comprise step: by disposing super node near a node of the descending P of being arranged in front of the importance values that calculates to extend the life cycle of described sensor network, 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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