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

sonu4sona@yahoo.com

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]