International Journal of Scientific Research Engineering & Technology (IJSRET) Volume 1 Issue6 pp 001-003 September 2012 www.ijsret.org ISSN 2278 - 0882
IJSRET @ 2012
A Simulation Study of Behaviour of Mobile Zigbee Node
Ms. Sonal J. Rane Department of Elect. Engg., Faculty of Tech. & Engg., M.S.University of Baroda
ABSTRACT Wireless Sensor Networks (WSN) has been researched
in recent years. WSNs have inherent and unique
characteristics compared with traditional networks. It
consists of light-weight, low power and small size sensor
nodes (SNs). They have ability to monitor, calculate and
communicate wirelessly. Sensor nodes should send their
collected data to a determined node called Sink. The sink
processes data and performs appropriate actions. In this
paper, an accurate simulation model, the behaviour of a
mobile Zigbee node passing through the radius of
multiple PANs is examined using OPNET simulator.
The performance metrics like: PAN Affiliation, Data
Dropped, Traffic Received are reported.
Keywords: Wireless Sensor Network, OPNET, Zigbee,
Traffic Received, PAN Affiliation
I. INTRODUCTION At present days, wireless sensor network(WSN) is
among the most talked about research fields in the
area of information and communication technologies.
WSN is a collection of sensor nodes distributed
over an area, either large or small, in order to
collect and distribute data for achieving some
specific goals. There exist a number of
communication protocols for the wireless sensor
networks, among those ZigBee is the leading global
standard for low-cost, low-data-rate, short-range wireless
networks with longer battery life[1]. Technology
defined by the Zigbee specification is intended to be
much simpler and less expensive than that of other
WPANs. The simplicity and cost of Zigbee networks
makes them a great candidate for wireless control and
monitoring applications. [2]
A. ZigBee
Figure 1: A typical example of ZigBee in Home
Automation [3]
Zigbee communication protocol is the most popular
among all the wireless sensor network
communication protocols. The Zigbee protocol is based
on the IEEE 802.15.4 standard. The IEEE 802.15.4
defines the standards for the physical layer and the
MAC layer of the communication stack. The Zigbee
standard defines the upper layers of the
communication stack – the network layer and the
application layer.
B. Device Types
1) Coordinator: This device starts and controls the
network. The coordinator stores information about the
network, which includes acting as the Trust Center and
being the repository for security keys.
2) Router: These devices extend network area
coverage, dynamically route around obstacles, and
provide backup routes in case of network congestion or
device failure. They can connect to the coordinator and
other routers, and also support child devices.
3) End Devices: These devices can transmit or
receive a message, but cannot perform any routing
operations. They must be connected to either the
coordinator or a router, and do not support child devices.
II. SIMULATION SETUP & RESULTS
Many Performance metrics can be considered for the
performance evaluation for the mobile node of the
wireless sensor network, some of the performance
metrics that considered in this paper are as follows. [5]
Data Dropped: Higher layer data traffic (in
bits/sec) dropped by the 802.15.4 MAC due to
consistently failing retransmissions. This
statistic reports the number of the higher layer
packets that are dropped because the MAC
couldn't receive any ACKs for the
(re)transmissions of those packets or their
fragments, and the packets' retry counts reached
the MAC's retry limit.
Traffic Received: Application traffic received
by the layer in packets/sec. This statistic is
dimensioned by ZigBee Network (PAN ID) for
values of PAN ID ranging from 1 to 255. All
International Journal of Scientific Research Engineering & Technology (IJSRET) Volume 1 Issue6 pp 001-003 September 2012 www.ijsret.org ISSN 2278 - 0882
IJSRET @ 2012
other PAN IDs (including auto-assigned PAN
IDs) will be combined into the '0' statistic.
PAN Affiliation for Coordinator: This
represents time that the node joins a network.
Fig. 1 Snapshot of a network having three co-ordinators
and one mobile node [5]
As shown in Fig.1, network has three coordinators
having Pan id 1,2 and 3.The network also contains a
node which is mobile. Initially it is placed near to Pan 1,
with its Pan id set to Auto-Assigned. The transmit power
of all the three coordinator is configured to 2 mW so that
their coverage areas do not overlap.
The trajectory of mobile_node_1 is configured to take
the node through the coverage area of each of the three
PANs over the course of 20 minutes. Based on this
trajectory, it is expected that mobile_node_1 will
initially join PAN 1, then switch to PAN 2, and finally to
PAN 3, which it should remain joined to.
The traffic on each node except mobile_node_1 is
configured as Random destination. When they join the
network, they will choose a random node within their
own PAN and send traffic to that node for the rest of the
simulation. Mobile_node_1 is configured to send traffic
to its parent node.
Fig. 2 PAN Affiliation
As shown in fig. 2 mobile_node_1 joined to PAN 1 for
the first 4 minutes of the simulation. The node then
briefly unjoins from the PAN (PAN ID -1), then
promptly joins PAN 2. At 12 minutes, the node unjoins
from PAN 2 and promptly joins PAN 3.
Fig. 3 Data Dropped
Fig. 3 Shows that 0(Zero) data packets dropped for most
of the simulation, with brief spikes around 4 and 12
minutes. Closer examination will show that each spike
occurs just before the node switches PANs, during the
time when it is out of range of its parent but has not yet
left the PAN.
Fig. 3 Traffic Received (packets/sec)
As shown in fig the traffic received graphs for each PAN
are as expected. PAN 1's traffic is initially higher as it
has an additional node (mobile_node_1). When
mobile_node_1 switches to PAN 2, the traffic received
for PAN 1 decreases while the traffic received for PAN
2 increases. A similar thing happens again for PANs 2
and 3 at around 12 minutes, when mobile_node_1
switches PANs again.
III. CONCLUSIONS This paper presented a simulation study to analyse the
effects of behavior of a mobile ZigBee node passing
through the radius of multiple PANs, is examined using
OPNET simulator. 0(Zero) data packets dropped for
most of the simulation, with brief spikes around 4 and 12
minutes as mobile_node_1 joined to PANs. Each spike
occurs just before the node switches PANs, during the
time when it is out of range of its parent but has not yet
left the PAN. Also traffic received graphs for each PAN
becomes higher as it has an additional node
(mobile_node_1). When mobile_node_1 switches to
PAN, the traffic received for previous PAN decreases
while the traffic received for recently joined PAN
increases. The scenarios considered are mainly taken
International Journal of Scientific Research Engineering & Technology (IJSRET) Volume 1 Issue6 pp 001-003 September 2012 www.ijsret.org ISSN 2278 - 0882
IJSRET @ 2012
from the literature. Such a study would be essential since
energy consumption is very critical for WSNs.
ACKNOWLEDGMENT Authors are thankful to Dept. of Elect. Engg., Faculty of
Tech. & Engg., M.S.University of Baroda for technical
help in doing this work.
REFERENCES [1] Adnan Faisal ,”PERFORMANCE EVALUATION
OF WIRELESS SENSOR NETWORKS USING
QUEUEING NETWORK MODELS”, 2008/2009
[2] Mehran Ferdowsi ,” Simulation of ZigBee Wireless
Sensor Networks” Final Report Spring 2012
[3] Jennic, Jennic's ZigBee e-learning Course.
Available:
http://www.jennic.com/elearning/zigbee/index.htm
[4] ZigBee Alliance, ZigBee Specification – June 2005,
http://www.caba.org/standard/zigbee.html
[5] OPNET Technologies, Inc. The Opnet Modeler
network simulator, 2009. (http://www.opnet.com)
[6] I. S. Hammoodi, B. G. Stewart, A. Kocian,
S.G.McMeekin “A Comprehensive Performance Study
of OPNET Modeler For ZigBee Wireless Sensor
Networks”, IEEE 2009.
[7] Getting Started with ZigBee and IEEE 802.15.4,
February 2008
[8] Holger Karl, Andres WIllig “Protocols and
Architectures for Wireless Sensor Networks”, John
Wiley and Sons Ltd, 2006.
[9] ZigBee Technology Overview. Internet:
https://docs.zigbee.org/zigbee-docs/dcn/09-5376.pdf,
2009, [Apr. 8, 2012]