ENHANCED ANTENNA POSITION IMPLEMENTATION OVER VEHICULAR- AD HOC NETWORK (VNET) IN 3D SPACE

164
Soumen Kanrar1
and Mohammad Siraj2
1
Department of Computer Engineering ,College of Computer and Information Sciences,
King Saud University, Riyadh -11543, SA
soumen_kanrar@yahoo.co.in
2
Department of Computer Engineering ,College of Computer and Information Sciences,
King Saud University, Riyadh -11543, SA
siraj@ksu.edu.sa
ABSTRACT
The technology related to networking moves wired connection to wireless connection.
The basic problem concern in the wireless domain, random packet loss for the end to end connection. In
this paper we show the performance and the impact of the packet loss and delay, by the bit error rate
throughput etc with respect to the real world scenario vehicular ad hoc network in 3-dimension space
(VANET in 3D). Over the years software development has responded to the increasing growth of wireless
connectivity in developing network enabled software. In this paper we consider the real world physical
problem in three dimensional wireless domain and map the problem to analytical problem .
In this paper we simulate that analytic problem with respect to real world scenario by using enhanced
antenna position system (EAPS) mounted over the mobile node in 3D space. In this paper we convert the
real world problem into lab oriented problem by using the EAPS –system and shown the performance in
wireless domain in 3 dimensional space.
KEYWORDS
EAPS, VANET, Bit error rate, throughput, antenna, wireless.
1 Introduction
Vehicular ad hoc networks (VANET) differ from usual mobile ad hoc networks (MANETs) in
many different aspects. First VANET consist of highly mobile nodes which moves in the same or
opposite directions. The node moves along the two different paths or in a curve . In a shared
wireless medium, during the communication establishment between the mobile nodes, blindly
broadcasting packets may lead to frequent contention and congestion among neighboring nodes.
This problem is some time referred to as the broadcast storm problem while multiple solution
exit to alleviate the broadcast storm in the usual MANET environment. In this paper we consider
particular types of VANET problem in 3 dimensional spaces. Here we consider the vehicle as the
mobile node. The vehicle receives alert message from the ground station and this message is to be
relayed to the neighboring vehicles. The received packets will be relayed by the vehicle which is
in high speed motion in 3 dimension space. The distance based schemes used in vehicular ad hoc
network are weighted p-persistence Broadcasting, slotted 1-persistence broadcasting and slotted

165
p-persistence to find a traffic flow pattern for the vehicular ad hoc network [1]. The performance
for the mobile node in ad hoc network by broadcasting the packets scales at the receiver node
[2].Various threshold-based techniques have been implemented to solve the broadcast storm
problem in mobile domain [3] such as counter–based, distance based and location based.
Directional antenna is used to mitigate broadcast redundancy and alleviate contention at the MAC
layer [4].Various mathematical models are used to reduce the redundancy in the broadcast storm
problem for mobile Ad hoc network [5]. Real world flight data is used in 3 dimensional spaces to
validate by simulating vehicular ad hoc network [6]. By mounting isotropic antenna over the
mobile node, performance of the network is achieved by message exchange in context client –
server connection in wireless domain [7]. In [8] authors have considered Realistic “Energy
consumption” model in physical layer for a device in mobile ad hoc network .In our work the
proposed scheme don’t require a node to keep track of its neighbors.
2. Proposed Model
In our proposed real time problem we consider “free space propagation model” . The aircraft is
a receiver x
R (consider as mobile node). It receives message from the ground station in the 3D
space via the figure -1 and figure-1.1 . The receiver (ie aircraft) is in an arbitrary height and
receives the message from the ground station x
T (fixed base station as the transmitter). We mount
three antennas (directional, isotropic and cone antenna) over the base station i.e ground station
and isotropic antenna over the aircraft. Here the aircraft moves in a particular trajectory from the
earth surface. There should be a minimum distance between every aircraft. There are more than
one aircraft at a particular height , maintaining a minimum distance among them. If we consider
the aircraft as the vehicle and the ground station as the fixed base station, then clearly it is
vehicular ad hoc network (VANET). Now the base station broadcast the alert massage and that
alert massage is to be relayed between the neighbor aircrafts. Due to broadcasting from the fixed
base station and from the relayed packet by neighbor’s aircraft ( using the fixed channel
frequency) , the problem of packet collection and contention for random broadcasting arises.
Redundant broadcast is also an issue for this problem scenario. In this paper we show the system
performance by measuring bit error rate and throughput by using “Enhanced antenna position
system (EAPS)” for various types of antennas mounted over the mobile node.
Diagram for the proposed Model

166
Figure 1.1
Figure-1 represent the movement of the aircraft’s and figure-1.1 represent the different position of
the vehicle in its motion. According to figure 1.1 points A, B, C represent the position of the
vehicle and D is the transmitter (Ground station)
3 Preliminaries
Manet: (Mobile ad hoc network) consist of a set of mobile hosts that may communicate with one
another from time to time. No base station is supported. Each host is equipped with a CSMA/CA
(carrier sense multiple access with collision avoidance) transceiver .In such a environment a host
may communicate with another directly or indirectly.
Redundant rebroadcast: When a mobile host decides to rebroadcast message to its neighbors
which already have the message.
Contention: After a mobile host broadcast a message, if many of its neighbors decide to
rebroadcast the message, these transmission ( which are all from nearby hosts) may severely
cause contention with each other.
Collision: Due to deficiency of back off mechanism in mobile domain , the lack of RTS/CTS
dialogue and the absence (CD) collision detection, collision is more likely to occur and cause
more damage in vehicular ad hoc network.
Directional Antenna: A directional antenna such as a parabolic antenna attempt to radiate most of
its power in the direction of a known receiver.
Isotropic antenna: Isotropic antenna is an antenna that transmits equally in all directions.
Cone antenna: A conventional discone antenna is a cone antenna. This antenna typically
has a feed structure that is within the cone. The cone antenna is used in wireless local area
network (WLAN).
Antenna gain: It is power output, in a particular direction, compared to that produced in any
direction by a perfect omni directional antenna (isotropic antenna).Antenna gain is a measure in
dB that how much more power an antenna will radiate in a certain direction with respect to that
which would be radiated by a reference antenna. The flowing equation represents the relationship
between antenna gain and effective area,
4 e
A
π 2
4 e
f A
π
G= ----------- = ---------------
2
λ 2
c
Where, G = Antenna gain, e
A = Effective area, f = Carrier frequency, c = speed of light
λ = Carrier wavelength.

167
Azimuth angle: The Azimuth angle, often denoted with a θ is the angle that the direct
transmission makes with respect to a given reference angle (often the angle of the target receiver)
when looking down on the antenna from above.
Elevation angel: The elevation angle is the angle that the transmission direction makes with the
ground elevation angle and is denoted with aφ .
Free space model: The free space propagation model assumes the ideal propagation condition
that there is only one line of –sight path between the transmitter and receiver.
H.T.Friis presented the following equation to calculate the received signal power in the free space
at distance d from the transmitter. The analytic form of free space model is
2
t t r
PG G λ
( )
r
P d = -------------------
2 2
(4 ) d L
π
t
P is the transmitted signal power, t
G and r
G are the antenna gains of the transmitter and
receiver respectively, L (1≤ L) is system loss and λ is the wavelength.
Roll: Rotation around the front –to –back axis is called roll via fig- 2
Pitch: Rotation around the side –to – side axis is called pitch via fig- 2
Yaw: Rotation around the vertical axis is called yaw via fig -2
Figure – 2
4 System Model:
The “Enhanced Antenna positioning” model, includes all six variables need to describe the
mobile node in 3-D space.“ latitude, longitude, altitude, yaw( bearing) direction of traveling
pitch(angle of ascent) and roll ( rotation angle) at the node position value attributes. In addition,
the model incorporates Antenna position values (Theta)θ , horizontal angle (phi) φ and rotation
angle describing the attitude of the antenna mounted on the node. The model also includes
modified receive and transmit antenna gain pipeline stages that utilize these new variables to
describe the motion of an antenna mounted on a mobile node.
The altitude information of the mobile node is often reported in terms of roll, pitch and yaw.
Facing is a combination of the nodes yaw and geospatial facing.
Facing calculated by latitude and longitude and yaw value from the attitude.
The formula to determine node’s facing is
F= arctan( 1 1
,
n n n n
X X Y Y
+ +
− − ) + n
yaw .
YAW
ROLL
PITCH

168
Here 1
n
X + is the next longitude position.
n
X is the current longitude.
1
n
Y + is the next latitude position.
n
Y is the current latitude position.
n
yaw is the mobile node rotation around its z axis.
The pointing direction of the antenna is assumed to coincide with the positive z-axis of the
antenna gain pattern.
For calculating pointing direction s the antenna to the mobile node (receiver which is vehicle or
aircraft via fig-1) is fixed. As the aircraft changes altitude and position, so does the pointing
direction of the antenna. The vector that identifies this pointing position defines the azimuth and
elevation angles that map to an antenna gain in the antenna pattern. In 2 dimensional space we
consider altitude remain fixed but the position is changing.
The antenna gain pipeline stages were modified to make use of the node’s attitude information.
First the antenna mounted and pointing direction attributes are read from the antenna module.
Each value, antenna mount and pointing direction is stored as three angles, phi theta and rotation
(φ ,θ ψ ). The antenna mount values are used to create two vectors one for the direction of the
antenna mounted on the platform and the other for the “up” value of the antenna’s bore sight. The
two vectors are modified by the node’s facing, pitch and roll. The facing pitch and roll are
described as three angles each representing the degree of rotation around the Z-axis, Y-axis and
node’s axis. Once the antenna vectors have been modified, the antenna actual pointing direction
in the simulation’s in 3D space is known.
The antennas pointing direction is used to determine the antenna gain from the antenna pattern.
5 Simulation Model
OPNET was used to build the simulation model. All the operations are done by using OPNET
kernel procedures. This is Baseline simulation .The Antenna gain pipeline stage is modified at the
transmitter and receiver according to the model requirement. The role of the pipeline stage is to
compute the antenna gain, throughput and Bit error rate, for the different position of the mobile
node.
The Enhanced Antenna position system (EAPS) is used to improve the performance gain. In
general EAPS uses two modes
1) Fixed to object
2) Locked to object
Fixed to object: The fixed to object mode is describing the movement of an antenna that
mounted over the mobile node and moves with the mobile node.
Locked to Target: In this mode the antenna always points at a specific target.
In both the modes, rotation angle parameters are used so the antenna rotates about its pointing
axis ref- (10).
5.1 Scenario Description
The system consists of a fixed transmitter and mobile node receiver with mobile Jammer moving
in a trajectory in the area around 8000x4000 meters. The receiver is model by using random
waypoint mobility i.e. the receiver moves randomly. The jammer node is used to create radio
noise. Here the transmitter and receiver modules use different channel for connection setup by
using the control packet . For message broadcasting and message forwarding the transmitter and
the receiver module use the data packet. The jammer is continuously changing its position
around the receiver by moving in a trajectory. The simulation is allowed to run for 12 mimutes .

169
The size of the packet send by the transmitter is 1024 bits. The transmitter broadcast each packet
in 1 minute. The transmission power at the transmitter is 20watts.The receiver node moves with
velocity of 10meter/second.
5.2 Node model
5.2.1 Transmitter : The transmitter composed of three modules via figure -3
1) Simple source i.e. packet generator.
2) Antenna target tracker module. This module tracks the antenna location.
3) Radio transmitter module. This module transmits the packets on a radio channel.
Figure -3
5.2.2 Receiver: The receiver composed of three modules via figure- 4
1) Antenna module.
2) Radio receiver module: This module defined the gain which will be adjusted at run time.
3) Sink processor module: This module store the received packets.
Figure -4

170
5.3 Summarizes the simulation parameters
Table-1
Transmission power 20 w
Simulation time 12m
Movement area 8x4 km
Node Movement speed 10 meter/sec
Modulation BPSK
Packet size 1024 bits
Packet interval Time
(broadcast interval)
1.0m
6 Performance analyses:
For the performance of the system, in this paper we study the bit error rate and the throughput for
the different types of antenna used. Isotropic, directional antenna, full cone antenna were
mounted over the transmitter and the isotropic antenna over the receiver mobile node (vehicle).
We move the jammer in a trajectory that artificially improves the situation as real world.The
jammer and the transmitter produce packet independently and asynchronously.
Min-0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Figure-5 Bit error rate with no antenna tracker
Bit error rate is concerned about the rejection of packet, which the vehicle receives with error.
Whereas in the case of throughput, how many packets are received properly with respect to the
packet transmitted from the transmitter in presence of the jammer. The jammer artificially
generate noise packet according to the figure- 5 and figure -6. The simulation is done by packet to
packet basis. In the case of received power, we compare signal strength at the receiver side to the
transmitted signal power. The jammer artificially generate noise as in real life scenario.
Figure -5 and figure -6 represent the bit error rate without antenna tracker and with antenna
tracker in context of figure 1.1

171
Min- 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Figure -6 Bit error rate with antenna tracker
Bit error rate initially is zero at the receiver node (vehicle) because the distance between the
jammer node and receiver node is large. After 5.5 minutes the direction vector between the
jammer antenna and the receiver antenna is in line with the direction of gain of receiver antenna.
The receiver node (vehicle) get maximum bit error during the interval 6.5 to 8.5 minutes and 9.0
to 11.0 minutes for the isotropic antenna via –figure 5 and figure-6 and the interval 6.5 to 7.5
for other types of antenna which are mounted over the receiver node (vehicle) via figure -5 and
figure-6.
Figure -7 and figure -8 represent the throughput of the system with antenna tracker and without
antenna tracker in context of figure-1.1. Clearly it seen from the figure during the time interval
6.5 to 8.5 minutes and during the interval 9.0 to 11.0 minutes the throughput approaches to zero
for the isotropic antenna mounted over the receiver vehicle, where the Bit error rate is maximum.
During the interval 6.5 to 7.5 minutes throughput approaches to zero for the other types of
antenna mounted over the receiver mobile vehicle.

172
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Figure-7 Throughput with no antenna tracker
Min 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Figure-8 Throughput with antenna tracker
In the figure -7 and figure -8, initially the throughput is maximum for all types of antenna
mounted over the receiver mobile vehicles but it decreases to zero with the increase of time (at
6.5 minute). Throughput almost approaches to maximum 1.0 and the Bit error rate is maximum
via figure- 5 and figure- -6 (0.025 errors/ bits).

173
7.Concluding Remarks:
In this paper we have considered the real life problem in vehicular ad hoc networks in 3
dimension space. In this paper we have shown the performance of the vehicular ad hoc network
in 3 dimensional space with bit error rate and throughput using OPNET simulator. This paper
can be further extended to measure the broadcast redundancy and the zone wise message
broadcasting with the help of clustering in high speed ad hoc networking.
For further work, to get better performance evaluation there is a need to create complex
simulation scenarios. Algorithms have to be developed and the complex traffic pattern taken into
consideration.
REFERENCES:
[1] Broadcast storm Mitigation Techniques in Vehicular Ad hoc Networks,N.Wisitpon, Gphan and
.K.Tonguz,J.S.Parikh,P.Mudalige, F.Bai,V.Sadekar IEEE Wireless communications December -
2007 (Open call)
[2] Broadcast Reception rates and effects of priority access in 802.11 based Vehicular-Adhoc
networksM.Torrent –Moreno, D.Jiang and H.Hartenstien Proc.ACM Int’l wksp Vehicular Ad hoc
Networks – Philadelphia PA Oct 2004
[3]. S.N. et al “ The Broadcast storm problem in a mobile Ad hoc Network “ Proc . ACM int’l conf
.Mobile computing and Networking – SEATTLE WA-1999.
[4] C. Hu, Y. Hong and J. Hou “ On Mitigating the Broadcast storm problem with directional antennas”
Proc IEEE ICC vol-1 Seattle WA May 2003
[5] SZE –Yao Ni , Yu –Chee Tseng ,Yuh-Shyan,Jang- ping Sheu “The Broadcast storm problem in a
mobile Ad hoc Network” ACM -1999.
[6] R.Preston, J Doane, D.Kiwior “Using real world data to create OPNET Models DRAFT” The -
MITRE Corporation
[7] Optimizing the performance of MANET with Enhanced Antenna position system Jackline Alphones
and Mohamed Naufal M.Saad IJCSNS -2009 Vol -9 No -4.
[8] .“Simulating mobile ad hoc networks in city Scenarios” IIya Stepanov, Kurt Rothermel Elsevier-
Computer, communication -2007.
[9]. ”Transmission Scheduling in Ad hoc Networks With Directional Antennas ”L.Bao and J.J Garcia –
Luna- Aceves ACM/Sigmobile Mobicom,28sep 2002.
Arne Schmitz, Martin Wenig “The Effect of the Radio Wave Propagation Model in mobile
Wireless Networks” MSWiM 2006 ACM
[11] Illya Stepanov, Kurt Rothermel ,On the impact of a more realistic physical layer on MANET
simulation results ScienceDirect Wireless Networks 6 (2008) pp 61-78
[12] Gianni A. Di caro, Fredrick Ducatelle, and Luca m. Gambardella “A Simulation study of routing
performance in realistic urban scenarios for MANETS “– Proceedings of ANTS - 2008
[13] Models for Realistic Mobility and radio wave propagation for Wireless Networks Simulation
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!
" #
within a Packet Simulator”. IEEE Vehicular Technology Conference, Sept 2000.

174
[15] www.opnet.com
Authors
Soumen Kanrar received the M.Tech. degree in computer science from
Indian Institute of Technology Kharagpur India in 2000. Advanced
Computer Programming RCC Calcutta India 1998. and MS degree in
Applied Mathematics from Jadavpur University India in 1996.
During 2001-2003 he worked in Techno India as faculty in computer-
engineering department. During 2003-2005- he worked in Dr. B.C.Roy
Engineering college India as faculty in the Computer Science and
Engineering department. During 2005-2008 he worked in Durgapur
Institute of Advanced Technology India as faculty in the Department of
Computer Science and Engineering. Currently working as a Research
Associate in the College of Computer & Information Sciences, King Saud
University, Riyadh, Saudi Arabia
Mohammad Siraj received his M.E degree in Computer Technology and
Applications from Delhi College of Engineering ,Delhi-India in 1997 and
BE degree in Electronics and Communication Engg from Jamia Millia
Islamia, New Delhi in 1995. He has worked as Scientist in Defence
Research and Development Organisation (DRDO) Ministry Of Defence,
India from 1995- 2000. Currently he is working as a Lecturer as a Lecturer
in the College of Computer & Information Sciences, King Saud University,
Riyadh, SA

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