J. Software Engineering & Applications, 2010, 3, 1167-1171
doi:10.4236/jsea.2010.312137 Published Online December 2010 (http://www.scirp.org/journal/jsea)
Copyright © 2010 SciRes. JSEA
Research on Wireless Sensor Networks Topology
Models
Ziqing Zhang, Hai Zhao, Jian Zhu, Dazhou Li
Information Science and En g i ne e ri n g , Northeastern University, Shenyang, China.
Email: zhangziqing100@163.com, zhhai@neuera.com
Received November 17th, 2010; revised November 28th, 2010; accepted December 14th, 2010.
ABSTRACT
The topology con trol is one of the research focuses in wireless sensor networks. Different netwo rk topologies will have
different effects on the properties of the network, such as the reliability, energy consumption and latency. In order to
study the relationship between the topology and the network performance, in this paper we have designed three kinds of
topology models which are regular hexagon topology model, plane grid topology model and equilateral triangle
topology model. Then the simulation experiments about these models have been implemented in NS2 and the simulation
results show that the plane grid topology has the best reliability.
Keywords: Wireless Sensor Network, Topology, Network Property, NS2
1. Introduction
Wireless sensor networks (WSNs) have wide fields of
application [1-2]. As a basic problem in the wireless
sensor network, the topology will directly affect the
service quality of “percep tion” which can be provided by
the sensor network and the entire network performance.
A good network topology has momentous significance
for the distribution of network space resources, perce-
ption of the environment, information acquisition and the
improvement of network viability [3].
Static network topology model is the most basic que-
stions [4]. Only the sensor nodes are disposed well in the
destination area can the other work and optimization be
further carried on. This article discusses the two-dimen-
sional topology mode l in the initial deplo yment of sensor
networks [5] .
Generally speaking, the initial deployment of nodes
mainly includes two ways. deterministic deplo yment and
stochastic deployment [6]. But the stochastic deploy-
ment way is very difficult for the numerous sensor nodes
to lay aside in suitable position. It’s very easy to cause
the sensor network covering unreasonable. For example,
the sensor nodes have been distributed dense or sparsely
in the partial target sector which seriously influence the
performance of network. Thereby, the determinism dep-
loyment has been mainly discussed in this article. The
sensor nodes are deployed in the certain position to cover
the number of nodes is requested few as far as possible.
The fixed surveillance area completely. Simultaneously.
In recent years, the scholars all over the world have con-
ducted relevant problems of topology, and certain pro-
gress has been made. Besides, some optimal topolo-
gical models have been put forward. Among which, there
are regular hexagon topology model [7], plane grid topo-
logy model [8-12] and equilateral triangle topology
model [13] which is the most classical topological model.
This paper discusses the three topological models and
network perfor mance.
2. The Topology Models of Sensor Node
Uniting the application characteristic and the system
performance of wireless sensor network [14], when dep-
loying the nodes the factors which should be mainly
considered include coverage [15], connection and energy
conservation [16 ]. The supposition of sensor's correspon-
dence radius is equal to R and all the sensor nodes have
similar sensation radius R.
2.1. Regular Hexagon Topology Model
The region of interest is divided into a series of closely
adjacent grid o f reg ul a r he xagon.
2.2. Plane Grid Topology Model
The region of interest is divided into a series of closely
adjacent grid of regular quadrangle.
Research on Wireless Sensor Networks Topology Models
Copyright © 2010 SciRes. JSEA
1168
2.3. Equilateral Triangle Topology Model
The region of interest is divided into a series of closely
adjacent grid of equilateral triangle.
The detection area can be covered completely with
these three kinds of sensor network and the whole net-
work can be kept working. The node in hexagon topo-
logical structure has three neighbor nodes at most, in
plane grid topology has four and in equilateral triangle
topology there are six.
When the covered area is 1000 m × 1000 m and the
length of topology is fixed 150 m. As can be seen from
Figure 1, the hexagon topolog y network n eeds 40 sensor
nodes, the plane grid topology needs 49 sensor nodes and
equilateral triangle topolog y needs 56 sensor nodes. This
means that, when the same size of region is covered with
the same quantity of sensor nodes. The length of topo-
logy arranged in hexagon is the shortest, second is the
plane grid structure and the longest is the equilateral
triangle topology.
If in the network each node’s wireless signal covers
massive other nodes, this will cause collision frequently
which affect the correspondence between the nodes, re-
duce the turnover rate and increase network delay.
3. The Result of the Experiment
The experiment will be carried in simulation platform
NS2. The three kinds of topological models will be simu-
lated and their performances will be analyzed. The para-
meters are established as in Table 1. The performance
indicators which will be test are showed in Table 2.
3.1. The Experiment of Hexagon Topology
After arranging the nodes which can be seen from
Figure 2(a), the length of topology is 130 m. Each node
in the network communicates with No. 24 node in the
center. The Figure 2(b) shows the charge ratio, Figure
2(c) shows the time delay and Figure 2(d) shows the
energy consumption in entire network. The data in No. 0
node expresses that No. 0 node as the source node tran-
smits 100 data packets to No. 24 goal node altogether.
The charge ratio is 0.30.
The data in No. 13 node expresses that No. 13 node as
the source node transmits 100 data packets to No. 24
goal node altogether. The charge ratio is 0.65.
3.2. The Experiment of Plane Grid Topology
After arranging the nodes which can be seen from
Figure 3(a), the length of topology is 140 m.
The length of topology in Figure 2 is 130 m and in
Figure 3 is 140 m. This means that when the same
quantity of sensor nod es are arranged in the same size of
region, the hexagon structure will be denser.
The ratio of reception in Figure 3(b) is higher than
that of Figure 2(b). Because the node in the sensor
network formed plane grid topology structure has more
neighbor nodes. The possible way for the data message
arriving at the goal node will be more. Therefore the rate
of receiving package is higher.
A comparison of Figure 2(c) and Figure 3(c) indi-
cates that the time delay in Figure 3(c) is longer. In
Figure 2(c), the time delay is 0.0350s when the data
packet is transmitted from No. 20 node to No. 24 node.
In Figure 3(c), the time delay is 0.0437s which is
greater than 0.0350 s. Because each node has more
neighbor nodes, not all the data packets arrive at the goal
node along the shortest path from the source node. So the
delay is longer. In addition, the communication nodes
between the source node and the goal node are more.
Wireless signals will conflict frequently when trans-
mitting the data message. So the network delay is in-
creased.
Consumption is more in Figure 3(d) than that of
Figure 2(d). Because in the network formed plane grid
Figure 1. Three kinds of typical topology mo dels.
Table 1. The establishment of parameter.
The scene will be simulated 1000 m*1000 m
The number of nodes 50
Wireless transmission model Shadowing
TTL 13
The distance of communica-
tion is 150 Charge ratio p=0.34
Routing protocol Flooding
The data packets sent to the
goal node 100 data packets, the
transmission gap is 0.2 second
Table 2. The performance indicators will be test for the
network.
1the ratio o
f
r
ece
p
tion
2
t
ime dela
y
3energy consumption in entire networ
k
Research on Wireless Sensor Networks Topology Models
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1169
(a) (b)
(c) (d)
Figure 2. Regular hexagon topology model.
(a) (b)
(c) (d)
Figure 3. Planar grid topology model.
Research on Wireless Sensor Networks Topology Models
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1170
(a) (b)
(c) (d)
Figure 4. Equilateral triangle topology model.
structure the node will receive more of the packets. The
intermediate nodes will consume more energy to tran-
smit and receive packets. So the total energy consum-
ption of network is more .
3.3. The Experiment of Equilateral Triangle
Topology
After arranging the nodes which can be seen from
Figure 4(a), the length of topology is 160 m.
The length of topology in Figure 2 is 130 m, in Figure
3 is 140 m and in Figure 4 is 160 m. This means that
when the same quantity of sensor nodes are arranged in
the same size of region, the equilateral triangle structure
will be sparser.
The comparison between Figure 3(b) and Figure 4(b)
indicates that the rate of receiving package is higher in the
network formed plane grid structure. Although the node
has less neighbor nodes in the plane grid topology sensor
network, the length of topology is shorter in this kind of
network. So the rate of receiving package is higher.
Furthermore, in the equilateral triangle topology network
each node has more neighbor nodes which induce
collision for the wireless signal and affect the reception of
the data packet.
4. Conclusions
In this paper three kinds of wireless sensor network
topology models are proposed which have been simu-
lated separately on simulation platform NS2. After the
analysis we can see that the distance between the source
node and goal node and the quantity of the neighbor
nodes affect the charge ratio, delay and the network en-
ergy consumption. The simulation experiments show that
when the same quantity of sensor nodes are arranged in
the same size of region, the length of topology in the
hexagon structure is the shortest, second is plane grid
topology model and in the equilateral triangle topology
network the length of topology is the longest. The rate of
receiving package is the highest in the plane grid topo-
logy sensor netw ork, second is the hexagon structur e and
the lowest is equilateral triangle topology netw ork. Final-
ly through a series of comparison we can see that the
network reliability of plane grid topology model is the
best.
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