An ANALYSIS of Communication Performance Accordingn to Antenna Directionality in UAV

8/2/2019 An ANALYSIS of Communication Performance Accordingn to Antenna Directionality in UAV

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Proceedings of IC-NIDC2010

AN ANALYSIS OF COMMUNICATION

PERFORMANCE ACCORDING TO ANTENNA

DIRECTIONALITY IN UAV OPERATION

ENVIRONMENT

MyungGu Park, Jaeil Jung

Laboratory of Multimedia Networking,Deptartment of Electronics and Computer Engineering, Hanyang University, Seoul, Korea

[email protected], [email protected]

Abstract

In recent years, Network Centric Warfare (NCW)

is widely accepted as a prominent concept in thefuture warfare. In particular, the collection of

information by using the Unmanned Aerial Vehicle(UAV) while minimizing exposure to enemy

forces is becoming an important concept to takeadvantage of an efficient war.

The characteristic selection of the antenna forefficient utilization of UAV is an important part

and it can improve or decline the performance ofwireless systems. Especially, the choice of thedirectional and omni-directional antennas is animportant factor to determine the distance, whichcan be the maximum transmission range of data.In this paper, we analyze the distance effect by

using two types of antennas (i.e., omni-directionaland directional antenna) in order to obtain the

optimized communication range between twostations (i.e., moving and fixed station). To achieve

this goal, we perform a simulation study by meansof QualNet 4.5 simulator and analyze the results byusing modeling and simulation method.

Keywords : UAV, NCW, Directionality, Antenna

1 Introduction

With the advancement of military sciencetechnology, the battlefield has been evolved to Network Centric Warfare (NCW) from platform based on hardware. This phenomenon may befound in various international conflicts such asIraq War. The reason why the importance of NCW

is being magnified is as follows: i) some country ofmiddle east is planning to constantly strengthen

military strength ii) there is the potential threatamong the countries directly involved toemphasize their sovereignty in maritime securityareas iii) with respect to domestic affair, there isvarious non-military threats such as terrorism,

natural disasters, etc.

NCW improves the efficiency of military force.Moreover, it is ensuring the information sharing tocomponents of battlefield by using the computer'sdata processing and a networked communicationstechnology. Tactical Network is the network that

NCW is implemented in the battlefield. Tactical

Airborne Networkis some kind of Tactical Network. Tactical Airborne Networkconsists offighter plane or UAV such as air platform. Tactical Airborne Networkis highly advanced bycombining Internet Protocol (IP) and Ad-hocnetwork. In recent years, Tactical AirborneNetwork is using directional antenna to enhancethe radio transmission range, the efficient use of

resources and Low Probability ofInterception/Detection (LPI/D).

A directional antenna uses the change of the signalintensity to track the moving object. Therefore,maximum transmission range is further than omni-

directional antenna. However, an additionalalgorithm is required for tracking. Conversely, theomni-directional antenna is not required anadditional algorithm for tracking because omni-directional antenna is not need to point a particulardirection. Therefore, the maximum transmissionwill be shorter than directional antenna.

In this paper, the fixed station antenna is classifiedwith two types such as a directional and omni-directional antenna in the UAV operating

environment. Then, the maximum transmissionrange was analyzed by using the Modeling andSimulation (M & S) method.

The rest of this paper is organized as follows. InSection 2, we describe the concept of NCW. In

Section 3, we introduce types and characteristics ofantennas used in NCW. The common simulationsetup and the evaluation result are given in Section4. In Section 5, we conclude our paper.

2 The concept of the Network Centric

Warfare (NCW)

NCW is able to do an efficient fight by networkingall the elements of battlefield (i.e., the detection

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system, the decision maker, the attacking system).The past warfare is a platform-centric. However,recent warfare regards the information moreimportant. These systems are represented cases

such as C4I (Command and Control,Communication, Computer, Intelligence) system,UAV and precision weapon system.

Figure 1. Principle of Network Centric Warfare(NCW)

NCW consists of three kinds of logical structure.First,Information Gridprovides data analysis andinformation exchange. Second, Sensor Gridimproves the situational awareness and makes the

high level of consensus on the battlefield. Finally, Engagement Gridimposes the conclusioneffectively and timely.

Figure 2. Principle of DirecNet

Today, each country is trying to build the NCWthat is suitable for their capabilities andcircumstance. UKhasNetwork-Enabled Operation(NEO) model, Canada and Australia are pursuing

the Network Capability (NEC) model. As another

example, defense-related industries of the UnitedStates are pursuing the DirecNet since 2006.

DirecNet is depicted in Figure 2. DirecNet provides data signaling rate up to 1Gbps to

commanders and troops for data transmission to allelements of the battlefield. Moreover, NCW

supports secure communication to the variousmedia.However, in the case ofKorea, an understanding

and awareness of NCW system is insufficient.Only recently, research and investment of NCWhas been conducting in order to improve the abilityto conduct the war.

3 Types and characteristics of the

antenna

An antenna is designed to transmit or receiveelectromagnetic waves. Compare with omni-directional antenna, directional antenna takesadvantages of throughput, the lower interferenceand battery life. Therefore, directional antenna isactively studying in NCW.

Figure 3. Transmission range of omni-directional

antenna

Figure 4. Transmission range of directionalantenna

As shown in Figure 3. omni-directional antenna is possible omni-directional communicationsregardless of the specific direction. In contrast, asshown in Figure 4, the communication range of adirectional antenna is wider than omni-directional

antenna in a certain direction when transmit powerequal to omni-directional antenna. Moreover,interference of the directional antenna is lowerthan omni-directional antenna because the signal iscollected in one direction. In addition, the

throughput can be more efficient when the gain isimproved in a direction of incoming signals.

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Directional antenna can be classified into two typeaccording to how to apply the beamformer(i.e., the switched beam and steered beam). Manyresearches have been conducted about these in the

existing system. Switched beam antenna uses apredeterminated weight according to the directionof the receiving signal. As shown in Figure 5.

steered beam antenna uses a measured weightaccording to receiving signal and interference.

Figure 5. Swiched beam antenna

Figure 6. Swiched beam antenna

4 Simulation

In this chapter, we analyze transmission range ofsignal according to the type of the fixed station'santenna.

4.1 Description of simulation

This simulation was performed by using the

Qualnet 4.5 program. Each component of thesimulation environment is as Table 1.

Figure 7. Picture of simulations component

Table 1. Simulation components

UAV speed 300km/h

Simulation time 3600s

Type of directional

antenna

Steerable Antenna

(Pattern 0)

UAV distance

(Terrain width)300km

Shortest path of UAV

and fixed station (h)55.8km

Figure 8. Transmission range of directionalantenna by pattern

Figure 9 Path of UAV

In this simulation, the maximum transmissionrange is defined L1. L1 depends on firsttelecommunication time (T2) and lastcommunication time (T3) between UAV and fixed

station. The directional antennas transmission

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range is estimated by Figure 8. That is configuredby Pattern. This simulation adopted Pattern 0.

4.2 Result of simulation

Table 2 Simulation result

Directionalantenna

Omni-

directional

antenna

First

communication

time (T2)

957s 1103s

Last

communication

time (T3)

2649s 2498s

Total

communication

time

1792s 1395s

The percentage of

communication

available sector inUAV's distance

49.8% 38.8%

Maximum

transmission range

(L1)

151km 128km

Table 2. is the result of simulation. When we

compare omni-directional antenna with directionalantenna, the first communication time (T2) isfaster and the last communication time (T3) isslower. Omni-directional antenna'scommunications sector is 11% longer thandirectional antenna in the UAV's total moving

distance. Therefore, we learn from these resultsthat omni-directional antenna's maximumtransmission range (L1) is 15% longer than

directional antenna between the UAV and the fixedstation.

5 Conclusions

Comparing In this paper, we research the concept

of NCW and the type of directional antenna andmaximum transmission range according to type offixed stations antenna in Tactical Airborne

Network.

The result of the simulation shows that the omni-directional antenna's maximum transmission rangeis 15% longer than directional antenna.

The future work is that the simulation resultcompare with calculated FADE Margin accordingto Link Budget. Moreover, we will test thethroughput when UAV and the base station arevery close such as UAV is taking off.

References

[1] U. Kumar, H. Gupta and S. R. Das, ATopology Control Approach to Using

Directional Antennas in Wireless Mesh Networks, Communication, 2006 IEEEInternational Conference on, Vol. 9, pp.4083-4088, 14-16 Jun. 2006.

[2] J. S. Blogh and L. Hanzo, ThirdGenerationSystems and Intelligent Wireless Networking Smart Antennas and Adaptive Modulation,

John Wiley & Sons, 2002[3] Diptiman Biswas, Selvanayaki K, Nilesh

Patel and V. Ramachandra, An AirborneAntenna System for Broadside Coverage withVarying Roll and Pitch Angles, AppliedElectromagnetic Conference AEMC-2007,

IEEE Digital Object Identifier:10.1109/AEMC.2007.4638021

[4] R. W. Beard and T. W. McLain, MultipleUAV cooperative search under collisionavoidance and limited range communicationconstraints,in Proc. 42nd IEEE Conf. Dec.

Contr., 2003, pp. 2530.

[5] C. Wilson, "Network Centric Warfare :Background and Oversight Issues forCongress", CRS Report for Congress. June 2.2004.

[6] Cebrowski, Arthur K and Garst ka, John J."Network-Centric Warfare : Its Origins andFuture." U.S Naval Institute Proceedings.January. 1998.

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An ANALYSIS of Communication Performance Accordingn to Antenna Directionality in UAV