Due to the existence of a large number of redundant data in the process of covering multiple targets, the effective coverage of monitored region decreases, causing the network to consume more energy. To solve this problem, this paper proposes a multitarget
With the rapid development of technology [
Two vital performance criteria that are required are coverage quality and energy management, which are also hot issues in the field of wireless sensor networks [
Coverage control technology is an important basic research issue and is one of the hotspots in the field of wireless sensor network, and coverage quality affects the network lifetime directly [
To study the wireless sensor network coverage problem better, as well as facilitate studying the NMCP algorithm, in this paper, we make the following assumptions: Each sensor node has certain perception ability, and their perception range and communication range are both circles. The perception range of a sensor node is far shorter than side length of the monitored region. Initially, all sensor nodes have the same energy and are clock synchronized. The location information of sensor nodes can be obtained with GPS. A sensor node’s perception radius is subject to normal distribution.
In the two-dimensional plane, each target node is covered by at least one sensor node, which is called the target coverage.
In a monitored region, if each target node is covered by
The time span from when a network begins running to when none target node is covered by the sensor nodes is called the network lifetime.
In the two-dimensional plane, the ratio of the total perception area of all sensor nodes to the monitored region is known as coverage quality.
Suppose each sensor node’s coverage rate is
Let
Therefore, the sensor node probability is
The joint probability of both rounds is
According to multiplication formula of probability, we get
The process to prove is complete.
If the coverage rate of each sensor node is
We will use mathematical induction in the proof. In the two-dimensional plane, any sensor node is not independent, so, according to the probability theory, when
When
Substitute formula (
When
The process to prove is complete.
In the two-dimensional plane, suppose the sensor node coverage rate is
In the two-dimensional plane, suppose the frequency a target node moves by is
Namely,
Suppose
Namely,
Substitute
After the sensor nodes cover the monitored region during time span
In the two-dimensional plane, suppose the fitting function of a sensor node energy consumption is
Take a bounded closed region sequence
Therefore, we just need to prove
Suppose there is
For each fixed
Namely, when
Therefore, formula (
Now, let
And because there is
The process to prove is complete.
For a sensor node, the energy consumption mainly happens in the sensing module and the communication module. When collecting
The energy consumption model for receiver module is
Let
On the premise that certain coverage rate is met, the maximum distortion is
The communication distance between nodes is less than or equal to half the difference between variance and the distortion.
Suppose the measured distance at the target node
Let
According to formulas (
Substitute formula (
The process to prove is complete.
In initial state, when transmitting
Suppose the current working node
Let
The energy consumed by node
So far, the total energy consumption of nodes on the path
In their initial state, the nodes work with the same amount of energy and are independent from each other. The basic properties of triangle show that
Namely, when
First, take the path from
The process to prove is complete.
Multilateral and unilateral node connection diagram.
Energy consumed in multilateral transmission is not higher than the energy dissipation in unilateral transmission in a multiple hops path in wireless sensor network [
NMCP algorithm takes the network running time round number as the basic unit, each round containing two aspects, namely, coverage control information and the stable state information of nodes. In working stage, the working nodes remain on, and all redundant nodes are off so as to save the network energy. At stable stage, each node has five kinds of running state, which are judge, compete, wait, start, and sleep states [
The state transition diagram.
Based on the idea in literature [
Calculate the perception intensity of cluster members.
The cluster member nodes send “
The cluster head node establishes a linked list and stores the information collected in it and then sorts the list according to the amount of energy in the sensor nodes; at the same time it assigns weights to those nodes which have higher energy.
Find qualified sensor nodes, and mark them.
If the target node is in the state of
After the traverse, the cluster header node schedules the optimal subset to finish covering the target node; otherwise, go to Step
See Algorithm
( and the energy threshold value. ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( (
In the analysis of NMCP algorithm,
When
Since
In order to verify the effectiveness and the stability of algorithm NMCP, we use MATLAB7.0 as the simulation platform for experiment and analysis. With the comparison experiment between NMCP and [
Performance parameters list.
Parameter | Value |
---|---|
Monitoring area | 400 |
|
10 m |
|
10 J |
|
600 s |
|
0.005 J |
|
20 m |
|
50 J/b |
|
50 J/b |
|
10 (J/b)/m2 |
|
100 (J/b)/m2 |
The comparison simulation experiments between algorithms NMCP in this paper and ETCA in [
Comparison of network lifetime.
The network lifetime and number of target nodes.
The run time comparison of the three algorithms.
Comparison of coverage rate.
Figure
Figure
Figure
To simulate the coverage rate, we carried out the comparison experiments between the algorithm in this paper and EPDM and ECAPM, with the monitored region id set to
Comparison experiments between the NMCP algorithm, ETCA algorithm, and LP_MLCEH protocol [
The second group of comparison experiments are carried out between NMCP algorithm, ETCA algorithm, and LP_MLCEH protocol in relation to the network lifetime in different monitored region. In the experiments, we give
The comparison experiments about prolonging the network lifetime are carried out between the NMCP algorithm, EPDM algorithm [
The comparison between working sensor nodes and sensor nodes.
In Figure
First, the coverage problems and the deficiencies in the wireless sensor network were analysed and, on basis of that, this paper put forward a nonlinear multiobjective
Finally, the effectiveness and feasibility of the NMCP protocol are verified by simulation experiments. Future work mainly focuses on how to achieve effective coverage on the boundary of monitored region and nonlinear coverage of irregular monitored region.
The authors declare no competing interests.
The study is supported by Projects U1304603 and 61503174 supported by the National Natural Science Foundation of China; Projects 14B520099, 16A520063, and 17A520044 supported by Henan Province Education Department Natural Science Foundation; Projects 142102210471, 162102210113, and 162102410051 supported by Natural Science and Technology Research of Foundation Project of Henan Province Department of Science; Projects 1201430560 supported by Guangzhou Education Bureau Science Foundation; Projects 2016A030313540 supported by Guangzhou Education Bureau Science Foundation.