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WiMAX Physical Layer Security Aspects: simulation and testing using opnet modeler 14.5

by patel, hardik Nayankumar, MS

Abstract (Summary)
WiMAX security is very wide area. IEEE 802.16 standard is used for WiMAX. In this report WiMAX physical layer security is described. Being a developing technology, the research that focuses on studying the suitability of WiMAX in different operating environments is of great importance. In this report, an IEEE 802.16 based system under jamming is evaluated in terms of the requirements set by the standard. IEEE 802.16 has OFDM based physical layer so there are multiple carriers. The main challenge is to perform jamming on these multiple carriers. The selection of the used jamming forms is justified by the easiness of generation, so that they could also exist in a natural environment. IEEE 802.16e fixed NLOS (None line of sight) is considered for simulation. The performance of the system was found out to greatly differ with the use of different jamming signals, allowing central areas to be identified, where system development should be focused on. In addition, from the basic theory point of view, rather surprising results were also found. This work should give a clear picture of how the studied WiMAX system performs under jamming as well as without the presence of jamming. The results show that some forms of interference degrade the performance of the system rapidly, thus the form of incoming jamming should be known and considered before deploying the system. OPNET MODELER 14.5 is the software used for the simulation purpose.
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Bibliographical Information:

Advisor:Dr. Upena Dalal

School:Sardar Vallabhbhai National Institute of Technology

School Location:India

Source Type:Master's Thesis

Embargo Type:Entire Document

End Date:12/21/2012

Keywords:Multicarrier, jamming, opnet, ofdma

ISBN:

Date of Publication:07/05/2010

Document Text (Pages 1-10)

s
DISSERTATION REPORT
ON

WiMAX Physical Layer Security Aspects: Simulation and
Testing Using OPNET MODELER 14.5

for
MASTER OF TECHNOLOGY
in
ELECTRONICS ENGINEERING
with specialization in
COMMUNICATION SYSTEMS

SUBMITTED BY
MR. HARDIK N. PATEL

(Roll No. P08EC915)

GUIDED BY
Dr. UPENA D. DALAL

ECED, SVNIT

2009-2010
DEPARTMENT OF ELECTRONICS ENGINEERING
SARDAR VALLABHBHAI NATIONAL INSTITUTE OF TECHNOLOGY
SURAT-395007


Page 2

Sardar Vallabhbhai National Institute of Technology

Surat-395007, Gujarat, India.

Electronics Engineering Department

CERTIFICATE

This is to certify that Mr. Hardik Nayankumar Patel Roll No. P08EC915 has
satisfactorily completed a dissertation on WiMAX Physical Layer Security
Aspects: Simulation and Testing Using OPNET MODELER 14.5as the
partial fulfillment of the requirement for the award of the degree in MASTER OF
TECHNOLOGY in ELECTRONICS ENGINEERING with the specialization
in COMMUNICATION SYSTEMS during the year 2009-2010.

Dr. Upena D. Dalal
Associate Professor, ECED
Guide
Dr. Suprava Patnaik
Head of the Department

Signature of Examiner:
SEAL OF DEPARTMENT


Page 3

WiMAX Physical Layer Security

Analysis of WiMAX Physical Layer Threats

Analysis of System Performance under the Influence
Of These Threats

Analysis of Threats Detection and Reduction
Techniques

Select Appropriate Parameters for Simulation

Create Appropriate Simulation Model

Perform Experiments


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WiMAX Physical Layer Security Aspects: Simulation and Testing Using OPNET MODELER 14.5 2010

ABSTRACT

WiMAX security is very wide area. IEEE 802.16 standard is used for WiMAX. In this report
WiMAX physical layer security is described. Being a developing technology, the research that
focuses on studying the suitability of WiMAX in different operating environments is of great
importance. In this report, an IEEE 802.16 based system under jamming is evaluated in terms of
the requirements set by the standard. IEEE 802.16 has OFDM based physical layer so there are
multiple carriers. The main challenge is to perform jamming on these multiple carriers. The
selection of the used jamming forms is justified by the easiness of generation, so that they could
also exist in a natural environment. IEEE 802.16e fixed NLOS (None line of sight) is considered
for simulation.

The performance of the system was found out to greatly differ with the use of different
jamming signals, allowing central areas to be identified, where system development should be
focused on. In addition, from the basic theory point of view, rather surprising results were also
found. This work should give a clear picture of how the studied WiMAX system performs under
jamming as well as without the presence of jamming. The results show that some forms of
interference degrade the performance of the system rapidly, thus the form of incoming jamming
should be known and considered before deploying the system. OPNET MODELER 14.5 is the
software used for the simulation purpose.

i


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WiMAX Physical Layer Security Aspects: Simulation and Testing Using OPNET MODELER 14.5 2010

Contents

Abstract i
List of Figures iv
List of Tables v
1. Introduction 1

1.1 Background
1.2 IEEE 802.16 Basics
1.3 Approach
1.4 Problem Definition
1.5 Solution Strategy
1
2
2
4
4

2. Literature Survey 5
3. Theory of WiMAX and Security Aspects 9

3.1 Network Reference Model
3.1.1 Functions of ASN
3.1.2 Functions of CSN
3.2 Introduction to WiMAX (physical layer operation)
3.2.1 Technological Aspects
3.3 Block Diagram in Detail
3.3.1 Convolution Coding
3.3.2 Interleaving
3.3.3 Symbol Mapping
3.3.4 Sub Carrier Allocation and Pilot Insertion
3.4 Duplex Methods
3.5 Channel Equalization
3.6 Introduction to OFDMA
3.6.1 Downlink Partial Usage of Sub carriers
3.6.2 Uplink Partial Usage of Sub carriers
3.6.3 Tile Usage of Sub carriers
3.6.4 Band Adaptive Modulation and Coding
3.7 Slot and Frame Structure
9
10
10
11
12
13
13
14
14
15
15
16
17
17
19
20
21

22

ii


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WiMAX Physical Layer Security Aspects: Simulation and Testing Using OPNET MODELER 14.5 2010

3.8 Antennas
3.9 Introduction to Jamming
3.9.1 Jamming Types
3.9.2 Jamming Attacks
3.9.3 Jammer‟s Classification
3.9.4 Jamming Detection
3.10 Issues and Overview of Jamming Reduction Techniques
24
26
26
30
31
32
34

4. Simulation Setup 38
4.1 Setting of Physical Layer Parameters in Simulation
4.1.1 Simulation parameters for single carrier jamming
4.1.2 Simulation parameters for Multi carrier jamming
38
38
39

5. OPNET MODELER Introduction 44
5.1 Overview of OPNET MODELER
5.2 Features of WiMAX Available in OPNET MODELER
5.2.1 Physical Layer Features
5.2.2 MAC LAYER Features
5.2.3 Framing
5.2.4 Network Layer Features
5.3 Various Tools of OPNET
5.4 Pipeline Stages in OPNET
44
44
44
45
45
45
46
46

6. Results 52
7. Conclusion and Future Scope
References
59
60

Acknowledgements 62
APPENDIX
A. OPNET MODELER 14.5 Installation Guide
B. OPNET MODELER 14.5 User Guide
63
72

Author’s Publications 74

iii


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WiMAX Physical Layer Security Aspects: Simulation and Testing Using OPNET MODELER 14.5 2010

List of Figures

Figure 3.1: Network Reference Model
Figure 3.2: Functional Stages of WiMAX PHY
Figure 3.3: Channel Estimation Using Pilot Sub carriers
Figure 3.4: DL PUSC sub carrier permutation scheme
Figure 3.5: UL PUSC sub carrier permutation scheme
Figure 3.6: Optional UL PUSC sub carrier permutation scheme
Figure 3.7: Band AMC sub carrier permutation
Figure 3.8: TDD frame structure
Figure 3.9: Sector Antenna Radiation Pattern
Figure 3.10: High Gain Antenna Radiation Pattern
Figure 3.11: Wideband Noise Jamming
Figure 3.12: Multi Carrier Jamming Signal Injected on OFDM Signal
Figure 3.13: Successful Channel Equalization
Figure 3.14: Unsuccessful Channel Equalization Caused By Jamming
Figure 3.15: Jamming Scenarios
Figure 3.16: Mesh with 2 base stations
Figure 3.17: Mesh with 2 base stations under jamming
Figure 3.18: Mesh with one base station
Figure 4.1: Scenario used for single carrier jamming.
Figure 4.2: Node model of jammer
Figure 4.3: Scenario used to simulate multi carrier jamming.
Figure 6.1: BER vs. simulation time
Figure 6.2: BER vs. simulation time
Figure 6.3: Throughput vs. simulation time
Figure 6.4: Delay vs. simulation time
Figure 6.5: Throughput vs. simulation time for uplink
Figure 6.6: Delay vs. simulation time for uplink
Figure 6.7: Throughput vs. simulation time for downlink
Figure 6.8: Delay vs. simulation time for downlink
Figure 6.9: Scrambling effect on BER

iv


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WiMAX Physical Layer Security Aspects: Simulation and Testing Using OPNET MODELER 14.5 2010

List of Tables

Table 1.1: Basics of IEEE 802.16 Standards
Table 2.1: Security Concerns for Network Users and Operators
Table 2.2: Security at Various Layers of WiMAX
Table 4.1: PUSC Permutation Scheme for Uplink
Table 4.2: PUSC Permutation Scheme for Downlink
Table 4.3: Simulation parameters and their values

v


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WiMAX Physical Layer Security Aspects: Simulation and Testing Using OPNET MODELER 14.5 2010

Chapter 1
Introduction

1.1 Background

Use of Internet is increasing day by day. Wi-Fi provides wireless access to the internet but
range is limited to certain meters only. So concept of WiMAX is introduced to increase the
range. WiMAX means world wide interoperability for microwave access. WiMAX is also known
as wireless broadband. WiMAX can cover a city by using cell concept which is very similar to
GSM. IEEE 802.16 standard is used for WiMAX. In wireless network security is very important
then wired network. In wired network physical layer security is not that much important as
compared to wireless network. The main reason is that in wireless networks air is used as
medium. In wired networks wires are used to carry data. So wired networks are some what
secure then compared to wireless networks. The main aim is to model physical layer Threats.
There are two ways to do this.
1. Simulation
2. Practical approach (Using Measurement setup)

In this report Simulation approach is used to Model Physical layer Threats. Practical
approach is very difficult to achieve it. The main thing is the cost of practical approach is very
high and WiMAX is new in India. IEEE 802.16 is the standard for WiMAX. WiMAX is also
known as wireless broadband. IEEE 802.16d-2004 is known as fixed WiMAX and IEEE
802.16e-2005 is known as mobile WiMAX [1]. In wired networks physical layer threats are not
important but in wireless air is used as medium so physical layer threats comes into picture [2].
In wireless jamming and scrambling are considered as physical layer threats [4]. Mac layer
threats are different than physical layer threats [5]. Here simulation approach is used to see the
performance of the IEEE 802.16e-2005 fixed NLOS (Non line of sight) system in jamming
environment. Jamming is achieved by introducing a source of noise strong enough to
significantly reduce the capacity of the WiMAX channel. The information and equipment
required to perform jamming are not difficult to acquire. Resilience to jamming can be
augmented by increasing the power of signals or increasing the bandwidth of signals via
spreading techniques such as frequency hopping or direct sequence spread spectrum. The

1


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WiMAX Physical Layer Security Aspects: Simulation and Testing Using OPNET MODELER 14.5 2010

practical options include a more powerful WiMAX transmitter, a high gain WiMAX
transmission antenna, or a high gain WiMAX receiving antenna [3]. It is easy to detect jamming
in WiMAX Communications as it can be heard by the receiving equipment. Law enforcement
can also be involved to stop jammers. Since jamming is fairly easy to detect and address, so it
does not pose a significant impact on both the WIMAX users and systems. Single carrier
jamming and multi-carrier jamming are considered here for simulation approach. Single carrier
jamming is used to jam the particular band of frequencies. In single carrier jamming carrier
frequency and bandwidth of the targeted system should be known. In multi-carrier jamming the
frequencies of carriers of targeted system should be known. Simulation approach is easy
compare to practical approach. The issues related to practical approach will be described in the
later part.

1.2 IEEE 802.16 Basics

This work relies on the IEEE 802.16 standard known as IEEE 802.16-2004;
although802.16e-2005 has already been published. This is due to the fact that the WiMAX
equipment used in the measurements has been built according to 802.16-2004 and no update
from the manufacturer is yet available. The 802.16 standard families comprise several related
standards. Standards 802.16a, 802.16c, 802.16d and 802.16e contain upgrades to the original
standard and have been integrated into the 802.16-2005 standards. The table given below gives
basic idea about IEEE 802.16 standard family and its parameters [1]. Basics of IEEE 802.16
standards are given in Table 1.1.

1.3 Approach

The main goal of WiMAX physical layer security is to prevent data and other personal
information that uses WiMAX applications. In this report only physical layer threats are
considered. WiMAX security is very wide area [2]. Whenever WiMAX security comes it means
security at each level of OSI model that WiMAX uses for providing the applications. In this
report jamming is discussed in detail. Simulation approach is used to model jamming in IEEE
802.16. OPNET MODELER is used to model the jamming in IEEE 802.16. The features of this
software are discussed later. Jamming is main physical layer threat for military. Now technology

2

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