CN103686924A - Oriented diffusion routing protocol based on returned time delay in wireless sensor network - Google Patents

Abstract

The invention discloses an improved oriented diffusion routing protocol in a wireless sensor network. A Sink node broadcasts Interest at a fixed period in a flooding way. A network node establishes gradients between nodes for broadcasting the Interest according to the sequence of the received Interest, and the gradients of the earlier reached nodes are smaller. After a gradient field of the whole network is established, one of the network nodes with the minimal gradient is selected as a next node; and if a plurality of nodes with same minimal gradients are provided, one node is randomly selected. The rest energy of the nodes are periodically detected, a threshold value is reduced by a half if the rest energy is lower than the threshold value; and meanwhile, the information of increasing the gradient is broadcasted to a neighboring node; and the gradient between the node which receives the information and the node is increased by the node which receives the information, and the gradients between the node which receives the information and other neighbours are reduced simultaneously. Results are compared to show that the protocol provided by the invention has longer network lifetime and more balanced network node energy consumption than the orientated diffusion protocol; and the improved oriented diffusion routing protocol is simpler.

Description

The directed diffusion routing protocol of wireless sensor network based on return time delay

Technical field

The present invention relates to wireless sensor network route technology.

Background technology

Route technology is the field of most study in wireless sensor network (Wireless Sensor Network, WSN).Existing routing mode can be divided into layer-stepping (hierarchical) and the large class of plane formula (flat) two, LEACH (Low Energy Adaptive Clustering Hierarchy) and directed diffusion (Directed Diffusion, DD) are respectively most typical representatives in this two class.

The DD agreement that the data of take are core (Data-centric) is considered to plane road by landmark result.DD agreement comprises diffusion interest, sets up gradient and three parts of path reinforcing, and it is by the one or more destination nodes of inquiring after to select down hop to sensor node induction information.DD agreement can, without any sensor node positional information in the situation that, be found the path between the sensor node of finding Sink and comprising its information of interest.In the process of establishing of path, node only need be understood the situation of its adjacent node, is a kind of route technology based on Partial controll completely.DD agreement can be applied to the tracking with dynamic object of obtaining of static information simultaneously.

DD agreement provides two kinds of gradients.The first be take the path delay of time as gradient, and present node is with the probability corresponding with Grad random next-hop node of selecting from a plurality of adjacent nodes.Random selection is the consideration for robustness and node energy consumption fairness, but what also brought thus each data transfer path is not the shortest, what energy consumption and time delay neither be minimum.The second gradient in DD agreement is transmission data rate, but needs path reinforcing process, and this process is actually the whole network of being initiated by information source node and floods, and this will bring larger transport overhead.

By DD agreement is improved, the invention provides a kind of directed diffusion routing protocol IEAF-DD(Interest Earliest Arrival First Directed Diffusion based on return time delay).Comparing result demonstration, IEAF-DD agreement has better energy-conservation and energy consumption balance effect than DD agreement, and has greatly reduced complexity.

Summary of the invention

The object of this invention is to provide wireless sensor network energy consumption and performance more simple directed diffusion routing protocol better again.

For achieving the above object, the technology path that the present invention adopts is:

The regular flooded broadcast interest of first step Sink node Interest;

Second step network node, for example A, according to the priority of Interest arrival, sets up and sends the Grad between Interest node.The Interest sending for the node of built vertical gradient ignores.Interest for receiving the node transmission of not setting up gradient, adopts following formula to set up gradient,

G _r=r

Wherein, r represents the sequence number that Interest that A receives floods, G _rrepresent that A returns to the Grad of the individual arrival node of r (1≤r≤n).The node arriving so at first, gradient minimum is 1, increases progressively successively.

The 3rd step network node is in transmission during data, choose at every turn and this node between the node of Grad minimum be next-hop node.If there are a plurality of next-hop nodes with identical minimum value, therefrom choose at random 1 as next-hop node.By that analogy, data are transferred to Sink by source node.

The 4th step node is according to self power consumption situation, adjust and adjacent node between gradient.Node is at interval of time T ₀, inquire about oneself dump energy, when find energy lower than set threshold value time, notify all adjacent nodes to increase and the Grad between it, upgrade subsequently threshold value.The present invention adopts " 1/2 " method, and new threshold value equals half of former threshold value.The initial initial threshold of node equals half of node primary power.Between node, the method for adjustment of gradient is, supposes that Grad is G _rnode because energy is too low, send the information that increases gradient, node A receives this information.Node A adjusts the gradient between itself and neighbor node according to following formula:

$\left\{\begin{array}{cc}{G_r}^{\′}=G_r;& (n=1)\\ \left.\begin{array}{cc}{G_r}^{\′}=G_r+1;& \\ \left.\begin{array}{cc}{G_i}^{\′}=G_r& (G_i=1)\\ {G_r}^{\′}=G_i-1& (G_i\≠1)\end{array}\right\}& (1\≤i\≤n,i\≠r)\end{array}\right\}& (n>1)\end{array}\right.$

Wherein, n is neighbours' number of node A, G _i' represent that A returns to the new Grad that the individual Interest information of i (1≤i≤n) arrives node.

Beneficial effect of the present invention: the present invention adopts time delay as gradient, node according to the gradient certainty of minimal time delay select next node, set up information source to shortest route current between Sink.Simultaneously according to node energy consumption situation, the gradient between knot modification.Avoided like this selecting the path that has redundant node, reduced network energy consumption.On the other hand by the adjustment of gradient between node, balancing network node energy consumption.What equalizing network node energy consumption of the present invention adopted is the method for " long-run equilibrium ", replaces the method for " short run equilibrium " of DD agreement.Comparing result demonstration, the present invention has the harmony of less node energy consumption and better node energy consumption than DD agreement, especially calculate simpler.

Accompanying drawing explanation

Fig. 1 is the Interest process that floods;

Fig. 2 is the gradient between node;

Fig. 3 is that redundant node is participated in transfer of data according to probability;

Fig. 4 is the energy contrast of energy minimum nodes;

Fig. 5 is the average residual energy contrast of node.

Embodiment

The regular flooded broadcast interest of step 1Sink node Interest.Interest comprises the description to message event, as the characteristics of objects that will detect etc., for each sensor node, judges whether to match with the own data of responding to.The example that Fig. 1 provides Sink to flood to the all-network node that comprises data source Source, Sink is first to its all neighbor nodes broadcast Interest, receives the Interest that the node of Interest also arrives to its neighbor node broadcast reception subsequently.But receive the Interest that the node that arrived from self flooding is broadcasted, abandon the grouping of reception, not repeated broadcast.By that analogy until all nodes in network all receive Interest.

The priority that step 2 network node A arrives according to Interest, sets up and sends the gradient between this Interest node.The Interest sending for the node of built vertical gradient ignores.Interest for receiving the node transmission of not setting up gradient, adopts following formula to set up gradient:

G _r=r

Wherein, r represents the sequence number that Interest that A receives floods, G _rrepresent that A returns to the Grad of the individual arrival node of r (1≤r≤n).

The node arriving so at first, gradient is minimum, increases progressively successively.And the Grad of node and the foundation of its neighbor node is unique.Below in conjunction with Fig. 2, illustrate:

1.Sink, when flooding Interest, is first transferred to node F, and after node F receives, setting up with the gradient of Sink is 1.With posterior nodal point F, flood Interest to Sink and node E, B and D.

2. due to the gradient of having set up with F, Sink the flooding of F of ignoring.

3. due to node E, B, D receives Interest first, they all set up and F between gradient be 1.

4. adopt same procedure,

1) node E is flooded to Node B, and this is that B receives Interest the 2nd time, so the gradient between B-E is 2;

2) node E is flooded to node A, and setting up gradient between A-E is 1; If E is later than B and floods, because E is

Receive Interest 2 times, so the gradient between E-B is 2;

3) node D is flooded to node C, and setting up gradient between C-D is 1;

5. node C is flooded to Node B, and this is that B receives Interest the 3rd time, so the gradient between B-C is 3;

Step 3 is set up after the internodal gradient fields of the whole network, and from Source node, selecting the node of gradient minimum is next-hop node, until Sink.

Be different from DD agreement, the present invention is the probability based on Grad no longer, in having the node of different Grad, chooses next-hop node.Below in conjunction with Fig. 3 explanation.

It is optional that in Fig. 3, B → F has 3 paths, is B → F respectively; B → E → F; B → C → D →.

In DD agreement, with certain probability, select one in three paths, the present invention only selects the node F of gradient minimum, by B direct, jumps to F.

If select two outer two paths, B is respectively 2 and 3 to the jumping figure between F.That is to say and will increase by 1 to 2 intermediate node forwarding data, this has correspondingly increased the energy consumption of network, and from transfer of data, this is unnecessary.

Step 4 node is at interval of a period of time T for example ₀, inquire about oneself dump energy, if dump energy lower than predetermined threshold value, notifies its all neighbor nodes to improve and this node between Grad, this node updates threshold value subsequently.

The method that threshold value is upgraded is, new threshold value upgraded to half that equals former threshold value, and the initial threshold of node is half of node primary power.

The method of gradient adjustment is that node A receives that Grad is G _rnode N _rafter the signal of the increase gradient of sending, the gradient between A adjustment and neighbor node is as follows:

1. for node N _r:

1) if A only has N _rneighbours, i.e. n=1, G _r'=G _r;

2) otherwise G _r'=G _r+ 1;

2. for node N _i, wherein 1≤i≤n and i ≠ r,

1) if Gi=1, G _i'=G _i;

2) otherwise, G _i'=G _i-1.

Wherein n is neighbours' number of node A, G _i' represent that A returns to the new Grad that the individual Interest information of i (1≤i≤n) arrives node.

Fig. 4 has illustrated that in identical network situation agreement of the present invention and DD agreement start working the time that first node energy exhausts from network.Fig. 5 has illustrated in identical network situation agreement of the present invention and DD protocol node average residual energy situation over time.

Claims (1)

1. a directed diffusion routing protocol for the improved wireless sensor network based on return time delay, is characterized in that:

(1) the regular flooded broadcast interest of Sink node Interest;

(2) priority that network node A arrives according to Interest, sets up and broadcasts the gradient between this Interest node;

(2.1) for the Interest that receives the node broadcasts of built vertical gradient, ignore;

(2.2) for the Interest that receives the node transmission of not setting up gradient, adopt following formula to set up gradient,

G _r=r

Wherein, r represents the sequence number that Interest that A receives floods, G _rrepresent that A returns to the Grad of the individual arrival node of r (1≤r≤n).The node arriving at first, gradient is minimum, increases progressively successively;

(3) network node is in transmission during data,

(3.1) choose and this node between Grad minimum node as next-hop node;

(3.2) if there are a plurality of nodes with identical minimal gradient, therefrom choose at random 1 as next-hop node;

(4) node is at interval of T ₀time, inquire about oneself dump energy, if dump energy lower than threshold value,

(4.1) new threshold value is upgraded to half that equals former threshold value, the initial threshold of node is half of node primary power;

(4.2) notify the Grad of all neighbor nodes raisings with this node, neighbor node for example A receives that Grad is G _rnode N _rthe gradient of sending increases after signal, and the gradient between A renewal and its neighbor node is:

$\left\{\begin{array}{cc}{G_r}^{\′}=G_r;& (n=1)\\ \left.\begin{array}{cc}{G_r}^{\′}=G_r+1;& \\ \left.\begin{array}{cc}{G_i}^{\′}=G_r& (G_i=1)\\ {G_r}^{\′}=G_i-1& (G_i\≠1)\end{array}\right\}& (1\≤i\≤n,i\≠r)\end{array}\right\}& (n>1)\end{array}\right.$

Wherein, n is neighbours' number of node A, G _i' return to the new Grad that the individual Interest information of i (1≤i≤n) arrives node for A.

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