Bhanuprakash123

4G CELLULAR NETWORK WITH WIMAX
Dept of ECE Page 1
A SEMINAR REPORT ON
4G CELLULAR ETWORK WITH WiMAX
Submitted to
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY,
ANANTHAPUR
In partial fulfilment of the requirement for the award of degree of
BACHELOR OF TECHNOLOGY
IN
ELECTRONICS AND COMMUNICATION ENGINEEING
BY
K.LAKSHMI BHANU PRAKASH REDDY 11691A0445
DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING
MADANAPALLE INSTITUTE OF TECHNOLOGY AND SCIENCE,
(Approved by AICTE, New Delhi, Affiliated to JNTU, Ananthapur)
Madanapalle–517325, Andhra Pradesh.

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MADANAPALLE INSTITUTE OF TECHNOLOGY & SCIENCE
(Approved by AICTE, New Delhi, Affiliated to JNTU, Ananthapur)
DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING
BONAFIDE CERTIFICATE
This is to certify that this technical seminar report “4G
CELLULAR ETWORK WITH WiMAX”
submitted in partial fulfilment of the requirement for the award of the
degree for bachelor technology in electronics and communication
engineering is a result of the bonafide work carried out by
K.LAKSHMI BHANU PRAKASH REDDY (11691A0445). He is
bonafide student of this college studying IV year B.Tech during
academic year 2011-2012.
Prof. A R REDDY, M.Tech, Ph.D
Head of the department,
Dept. of ECE.

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Acknowledgement
I extend my sincere gratitude towards Prof.Dr.A.R.REDDY, Head of the
Department, Dept of E.C.E for giving me his valuable knowledge and
wonderful technical guidance. I also thank all the other faculty members of
ECE department and my friends for their help and support.

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ABSTRACT
Different aspects of wireless networks are changing as a result of the continuous
needs in terms of speed, data rates and quality of service. Such aspects are required to be
adaptable within the same network or among networks of different technologies and
service providers. Consequently, Worldwide Interoperability for Microwave Access
(WiMAX) is one of the future generation networks (4G) that needs further study.
However, a major consideration for WiMAX to achieve mobility is the handover
mechanism that concerns with the mobile station movement within the range of network
coverage from one base station to another similar homogeneous or different homogeneous
network. In this paper, an intensive analysis to handover mechanism in WiMAX followed
by comparisons to WiMAX performance with UMTS and WiFi networks is carried out.
QualNet 4.5.1 simulator is used to simulate the comparison process homogeneously and
heterogeneously. Performance metrics of Throughput, End-to-End (E-2-E) Delay and Jitter
in the comparison during handover process in/between the wireless networks are used. The
simulation results are evaluated to identify the performance of the handover process over
WiMAX-WiMAX, WiMAX-UMTS and WiMAX-WiFi with respect to the selected
metrics. The environment of Wi-MAX-WiMAX has shown substantial enhancement of the
system Throughput, reduction of E-2-E Delay and Jitter.

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CONTENTS
PAGE NO
CHAPTER 1:INTRODUCTION
1.1Purpose and Scope------------------------------------------------
1.2 Overview of WiMAX Technology------------------------------
1.3 Fundamental WiMAX Concepts--------------------------------
CHAPTER 2: Operating Topologies
2.1 Point-to-Point (P2P)-----------------------------------------------
2.2 Point-to-Multipoint (PMP)----------------------------------------
2.3 Multi-Hop Relay----------------------------------------------------
2.4 Mobile----------------------------------------------------------------
CHAPTER 3:ARCHITECTURE
3.1Architecture of WiMAX network------------------------------------
3.2Standards for WiMAX--------------------------------------------------
3.3 Features of WiMAX-----------------------------------------------------
3.4Modulation & Multiplexing Schemes---------------------------
3.5 Objectives-----------------------------------------------------------
3.6 Problem Analysis---------------------------------------------------
3.7 Literature Review---------------------------------------------------
CHAPTER 4: Methodology
4.1QualNet Simulator---------------------------------------------------
4.2 Performance Metrics-------------------------------------------------
4.2.1 Throughput------------------------------------------------------------

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4.2.2 End-to-End (E-2-E) Delay----------------------------------------
4.2.3 Jitter-------------------------------------------------------------
4.3 Simulation Parameters--------------------------------------------
4.4 Simulation Environments----------------------------------------
4.5 Results--------------------------------------------------------------
4.5.1 Throughput Result-----------------------------------------------
4.5.2 End-to-End Delay Result---------------------------------------
4.5.3 Jitter Result-------------------------------------------------------
CHAPTER 5:SWOT ANALYSIS - 4G with WiMAX
5.1 WI-MAX Security Features-----------------------------------------
5.2 Security Associations ------------------------------------------------
5.3 Security Threats-------------------------------------------------------
CHAPTER 6:Countermeasures
6.1 Management Countermeasures --------------------------------------
6.2 Operational Countermeasures----------------------------------------
6.3 Comparisons of WiMAX and LTE--------------------------------
Discussion---------------------------------------------------------------------------------
Conclusion and Future Work----------------------------------------------
References----------------------------------------------------------------------

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LIST OF FIGURES
Figure 1: WiMAX Possible environments
Figure2: P2P Topology
Figure 3:PMP Topology
Figure 4:Multi-Hop Topology
Figure 5:Mobile Topology
Figure 6:OFDMA Resource Block Scheduling
Figure7:Cumulative numberof WiMAX deployment per frequency
Figure 8:QualNet layer model
Figure 9:WiMAX Security Framework

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LIST OF TABLES
Table 1:WiMAX Standards
Table 2:Simulation Parameters
Table 3: Comparisons of WiMAX and LTE

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CHAPTER-1
Introduction
The world is moving to the age of velocity in every field especially the wireless networks
field. To go along with it, it is needful to have faster facilities, more importantly in the
wireless networks. The need is to provide mobile wireless with higher data rates, Quality of
Service (QoS) and adaptability within the same network or among networks of different
technologies and service providers. The users should be able to get its potential whatever
they are using (PC, cell phone, electronic pad, etc. wise), and where ever they are sitting; at
home, walking and even driving [1].
Worldwide Interoperability for Microwave Access (WiMAX) is one of the future
generations (4G) promising networks to cover some of the consumers' needs. It is an
emerging technology that is designed to deliver fixed, and more recently, mobile
broadband connectivity. It promises to deliver last-mile wireless broadband internet
access capable of carrying data intensive applications. The 2005 version of WiMAX
provides data rate up to 40Mbits/s and 2011 version can support data rate up to 1 Gbitls
for fixed stations [1]. It is one of the latest developments and considered as a 4G (Fourth
Generation) technology. WiMAX supports data rate up to 75 Mbitls which is higher than
conventional cable modem and digital WiMAX subscriber line (DSL) connections
which are all wired access technologies The WiMAX trade name is used to group a
number of wireless technologies that have emerged from the Institute of Electrical and
Electronics Engineers (IEEE) 802.16 Wireless Metropolitan Area Network (MAN)
standards [3]. The main standards introduce mobility and currently receive a great deal of
interest in the telecoms world [2]. Figure 1 show environments that can be employed in
WiMAX [1].
The IEEE community has defined the IEEE 802.16e amendment (i.e. mobile WiMAX)
to support mobility. Mobile WiMAX of IEEE 802.16e defines wireless communication for
mobiles, moving at speed of 125 KMPH in the range of 2-6 GHz (802.16e). IEEE 802.16e
is implemented with Orthogonal Frequency-Division Multiple Access (OFDMA) as its
physical layer scheme [4]. Full mobility technology is different from one network to
another, and each technology has its own mobility characteristics [5]. To ensure high level
of mobility, it is important for WiMAX to have an efficient handover mechanism [6].

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This paper investigates the WiMAX mobility capabilities and issues related to
homogenous (between the same types of networks) and heterogeneous (between different
types of networks) mobility. Specifically, the paper focuses on the handover performance
of the WiMAX in comparison with similar WiMAX network or with other networks. For
performance evaluation, Throughput, End-to-End (E-2-E) Delay and Jitter metrics are
used as networks performance quality criteria to investigate the WiMAX mobility
capabilities and efficiency of handover process in the comparison with other wireless
technologies.

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1.1 Purpose and Scope:
The purpose of this document is to provide information to organizations regarding the
security capabilities of wireless communications using WiMAX networks and to provide
recommendations on using these capabilities. WiMAX technology is a wireless metropolitan
area network (WMAN) technology based upon the IEEE 802.16 standard. It is used for a
variety of purposes, including, but not limited to, fixed last-mile broadband access, long-
range wireless backhaul, and access layer technology for mobile wireless subscribers
operating on telecommunications networks.
The scope of this document is limited to the security of the WiMAX air interface and
user subscriber devices, to include: security services for device and user authentication; data
confidentiality; data integrity; and replay protection. This document does not address
WiMAX network system specifications, which address core network infrastructure and are
primarily employed by commercial network operators.4 This publication, while containing
requirements specific to Federal agencies, serves to provide security guidance for
organizations considering the implementation of WiMAX systems.
1.2. OVERVIEW OF WIMAX TECHNOLOGY:
A wireless metropolitan area network (WMAN) is a form of wireless networking that
has an intended coverage area—a range—of approximately the size of a city. A WMAN is
typically owned by a single entity such as an Internet service provider, government entity, or
large corporation. Access to a WMAN is usually restricted to authorized users and subscriber
devices.
The most widely deployed form of WMAN technology is WiMAX technology, which is
based in large part on the IEEE 802.16 standard. The industry trade association, the WiMAX
Forum5, coined the WiMAX trademark and defines the precise content and scope of WiMAX
technology through technical specifications that it creates and publishes. Early iterations of
WiMAX technology (based on IEEE 802.16-2004 and earlier) were designed to provide fixed
last-mile broadband wireless access. The IEEE 802.16e-2005 amendment added support for
enhanced user mobility. The latest standard, IEEE 802.16-2009, consolidates IEEE 802.16-
2004 and IEEE 802.16e-2005 in addition to IEEE 802.16 amendments approved between
2004 and 2008. IEEE also released IEEE 802.16j-2009 to specify multi-hop relay
networking. This section explains the fundamental concepts of WiMAX technology,
including its topologies, and discusses the evolution of the IEEE 802.16 standard.

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1.3 Fundamental WiMAX Concepts:
WiMAX networks have five fundamental architectural components:
Base Station (BS): The BS is the node that logically connects wireless subscriber devices to
operator networks. The BS maintains communications with subscriber devices and governs
access to the operator networks. A BS consists of the infrastructure elements necessary to
enable wireless communications, i.e., antennas, transceivers, and other electromagnetic wave
transmitting equipment. BSs are typically fixed nodes, but they may also be used as part of
mobile solutions—for example, a BS may be affixed to a vehicle to provide communications
for nearby WiMAX devices. A BS also serves as a Master Relay-Base Station in the multi-
hop relay topology . Subscriber
Station (SS): The SS is a stationary WiMAX-capable radio system that communicates with a
base station, although it may also connect to a relay station in multi-hop relay network
operations. Mobile Station (MS): An
MS is an SS that is intended to be used while in motion at up to vehicular speeds. Compared
with fixed (stationary) SSs, MSs typically are battery operated and therefore employ
enhanced power management. Example MSs include WiMAX radios embedded in laptops
and mobile phones. This document uses the term SS/MS to refer to the class of both MS and
stationary SS.6. Relay Station (RS): RSs
are SSs configured to forward traffic to other RSs or SSs in a multi-hop Security Zone (which
is discussed in Section 3.5). The RS may be in a fixed location (e.g., attached to a building)
or mobile (e.g., placed in an automobile). The air interface between an RS and an SS is
identical to the air interface between a BS and an SS. Operator Network: The
operator network encompasses infrastructure network functions that provide radio access and
IP connectivity services to WiMAX subscribers. These functions are defined in WiMAX
Forum technical specifications as the access service network (radio access) and the
connectivity service network7 (IP connectivity). WiMAX devices communicate using two
wireless message types: management messages and data messages. Data messages transport
data across the WiMAX network. Management messages are used to maintain
communications between an SS/MS and BS, e.g., establishing communication parameters,
exchanging security settings, and performing system registration events (initial network
entry, handoffs, etc.) IEEE 802.16 defines frequency bands for operations based on signal
propagation type. In one type, it employs a radio frequency (RF) beam to propagate signals
between nodes. Propagation over this beam is highly sensitive to RF obstacles, so an

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unobstructed view between nodes is needed. This type of signal propagation, called line-of-
sight (LOS), is limited to fixed operations and uses the 10 to 66 gigahertz (GHz) frequency
range. The other type of signal propagation is called non-line-of-sight (NLOS). NLOS
employs advanced RF modulation techniques to compensate for RF signal changes caused by
obstacles that would prevent LOS communications. NLOS can be used for both fixed
WiMAX operations (below 11 GHz) and mobile operations (below 6 GHz). NLOS signal
propagation is more commonly employed than LOS because of obstacles that interfere with
LOS communications and because of strict regulations for frequency licensing and antenna
deployment in many environments that hinder the feasibility of using LOS.

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CHAPTER:2
2.Operating Topologies
There are four primary topologies for IEEE 802.16 networks: point-to-point, point-to-
multipoint, multi-hop relay, and mobile. Each of these topologies is briefly described below.
2.1 Point-to-Point (P2P)
A point-to-point (P2P) topology consists of a dedicated long-range, high-capacity wireless
link between two sites.
Figure2: P2P Topology
Typically, the main or central site hosts the BS, and the remote site hosts the SS, as seen in
Figure 2-1. The BS controls the communications and security parameters for establishing the
link with the SS. The P2P topology is used for high-bandwidth wireless backhaul8 services at
NLOS a maximum operating range of approximately 48 kilometers (km) (30 miles) using
LOS signal propagation, and eight km (five miles) using NLOS.
2.2 Point-to-Multipoint (PMP)
A point-to-multipoint(PMP) topologyis composed of a central BS supporting multiple SSs,
providing network access from one location to many. It is commonly used for last-mile
broadband access, 9 private enterprise connectivity to remote offices, and long-range wireless
backhaul services for multiple sites. PMP networks can operate using LOS or NLOS signal
propagation. Each PMP BS has a maximum operating range of 8 km (5 miles), but it is

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typically less than this due to cell configuration and the urban density of the target coverage
area.
Figure 3:PMP Topology
2.3 Multi-Hop Relay
A multi-hop relay topology, defined by IEEE 802.16j-2009, extends a BS’s coverage
area by permitting SSs/MSs to relay traffic by acting as RSs. Data destined to an SS/MS
outside of the BS’s range is relayed through adjacent RSs. An RS can only forward traffic to
RSs/SSs within its Security Zone. A Security Zone is a set of trusted relationships between a
BS and a group of RSs. Data originating outside of a BS’s coverage area is routed over
multiple RSs, increasing the network’s total geographical coverage area, as seen in Figure 2-
3. Multi-hop relay topology typically uses NLOS signal propagation because its purpose is to
span large geographic areas containing multiple RF obstacles; however, technically it can
operate using LOS propagation as well. The maximum operating range for each node in a
multi-hop relay topology is approximately 8 km (5 miles), but the actual operating range is
typically less depending on environmental conditions (e.g., building obstructions) and
antenna configuration.

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Figure 4:Multi-Hop Topology
2.4 Mobile
A mobile topologyis similar to a cellular network because multiple BSs collaborate to
provide seamless communications over a distributed network to both SSs and MSs.
Figure 5:Mobile Topology
This topology combines the coverage area of each member BS and includes measures
to facilitate handoffs of MSs between BS coverage areas, as seen by the car MS in Figure 2-
4. It uses advanced RF signaling technology to support the increased RF complexity required
for mobile operations. Each BS coverage area is approximately 8 km (5 miles). Mobile
WiMAX systems operate using NLOS signal propagation on frequencies below 6 GHz.

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CHAPTER-3
ARCHITECTURE:
3.1Architecture of WiMAX network
All WiMAX devices such as MS, BS, AAA server, HA server, ASN Gateway are IP
based nodes. These nodes can directly plugged into IT backbone network. The BS is used
to perform the air interface and manage the radio resources. The data is being received
from mobile stations and send to mobile stations by air interface. The ASN Gateway
performed QOS policy management and mobility management between BSes, is also used
to bridged multiple BSes to backend core service network. A server is an authentication
server. It is an open source software which performs authentication process, HA performs
mobile IP. Its function is to implement roaming between ASN Gateways. HA is also an
open source software.
3.2Standards for WiMAX
IEEE 802.16 is a series of Wireless Broadband technologies, standardized by the
Institute of Electrical and electronics Engineers (IEEE).The IEEE 802.16 group was
formed in 1998 to develop wireless broadband. The following Table.l shows the IEEE
802.16 standard.
3.3Features of WiMAX
WiMAX is a wireless network that has a high class set of features with a lot of flexibility
in terms differentiates it from other metropolitan area wireless access technologies are: 1
.OFDM-based physical layer, 2. Very high peak data rates, 3. Scalable bandwidth and data
rate support, 4. Adaptive modulation and coding (AMC), 5. Link-layer retransmissions,
6.Support for TDD and FDD, 7.Orthogonal frequency division multiple access
(OFDMA), 8.Flexible and dynamic per user resource allocation, 9. Support for advanced
antenna techniques, 10. Quality-of-service support, 11.Robust security, 12. Support for
mobility, 13. IP-based architecture.
3.4MODULATION&MULTIPLEXING-SCHEMES:
To transfer data over the "air interface", modulation schemes are used. A
combination of varying modulation schemes are used in LTE and WiMAX networks.
These modulation schemes can be QPSK (Quadrature Phase-Shift Keying) or QAM
(Quadrature Amplitude Modulation), and the multiplexing schemes such as Input
Multiple Output). OFDMA in the physical layer is used by mobile WiMAX and OFDM
and SC-FDMA in the physical layer is used by LTE which allows the deployment in
different frequency ranges.
SI.
No
Year Features Stat
us
1 802.16 2001 W
Fixed Broadband ireless Access (10-66GHz)
S

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2 802.16.2 2001 Recommended practice for coexistence S
3 802.16c 2002 System profiles for 10-66 GH z S
4 802.16a 2003 Physical layer and MAC definitions for 2-11 GHz S
5 P802.16b License-exempt frequencies(Project withdrawn) W
6 P802.16d Maintenance and System profiles for 2-11GHz(project
merged into 802.16-
2004
M
7 802.16 2004 Air Interface for Fixed Broadband Wireless Access
System(rollup of 802.16-
2001,802.16a,802.16c and P802.16d)
S
8 P802.16.2a Coexistence with 2-11 GHz and 23.5-3.5GHz(project
merged into 802.16.2-
2004
M
9 802.16.2 2004 Recommended practice for eoexistence(Maintenance
and rollup of 802.16.2-
2001
C
10 802. 16f 2005 Management Information Base (MIB) for 802.16-2004 S
11 802.16-
2004/Cor.l
2005 Corrections for fixed operations(co-published with
802.16e-2005)
S
12 802.16e 2005 Mobile Broadband Wireless Access System S
13 802.16k 2007 Bridging of 802.16(an amendment to IEEE 802.1D C
14 802.16g 2007 Mobile Management Information Base(Project merged
into 802.16-2009
M
15 802.16 2009 Air Interface for Fixed and Mobile Broadband Wireless
Access System
C
16 802.16j 2009 Multihop relay C
17 802.16h 2010 Improved Coexistence Mechanisms for License-Exempt
Operation
C
18 802.16m 2011 Advanced Air Interface with data rates of 100Mbits/s
mobile and 1Gbits/s
fixed.
C
19 P802.16n Higher Reliability Networks In Progress P
20 P802.16p Enhancements to support Machine -to-Machine
Applications
P
OFDM (Orthogonal Frequency Division Multiplexing) and MIMO (Multiple
S=Superseded W=Withdrawn, M=Merged, C=Current, P=Progress
Table 1:WiMAX Standards.

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A.QPSK:
QPSK is a phase-shifting modulation scheme. To send data the carrier frequency phase is
shifted. Here in QPSK we can send two symbols by shifting the frequency in four different
phases (0, 90, 180, 270 degrees).
B.QAM:
QAM is a combination of two techniques, i.e. PSK (Phase-Shift Keying) and ASK
(Amplitude-Shift Keying) for modulation. Hence it allows higher transfer rates. To
distinguish between symbols (high = 1, low = 0) ASK uses different frequency amplitudes.
More symbols can be transferred by varying number of amplitudes and phases. Wireless
telecommunication networks widely uses digital 16-QAM (16 Symbols, 4 Bits) or 64-
QAM (64 Symbols, 6Bits) modulation schemes.
C.OFDM:
OFDM is a frequency division multiplexing modulation scheme which divides the data
transmission over several streams, and assigns one for each orthogonal subcarrier. In
wireless technologies such as WLAN, DVB-T or DAB OFDM is already been
successfully used. Also it allows a large number (several hundreds) of narrow-band
subcarriers. In comparison with other multi-carrier extension such as the WCDMA
(Wideband Code Division Multiple Access) multicarrier evolution, a 20 MHz bandwidth
could consist of four 5 MHz (sub)carriers. OFDM uses IFFT (Inverse Fast Fourier
Transform) and FFT (Fast Fourier Transform) for signal modulation. Figure 1 shows the
OFDM spectrum with the subcarrier division and the subcarrier spacing _f = 1=Tu, where
Tu isthe per-subcarrier modulation symbol time. The subcarrier spacing can range from a
few kHz up to several hundred kHz. The subcarrier spacing for 3GPP LTE is about 15
kHz, whereas WiMAX uses 11 kHz. Figure also shows theorthogonality between the
subcarriers that allows for highspectral efficiency. Major disadvantage of OFDM is that it
has a higher PAPR (Peak-to-average power ratio, also refer to as the crest factor or PAR)
which leads to
a higher power consumption. For this reason, 3GPP LTE uses Single Carrier FDMA,
which is also referred as DFTS-OFDM (Discrete Fourier Transform Spread OFDM). SC-
FDMA is a single carrier modulation which is basically a normal OFDM with a DFT-
based precoding. The main advantage of this approach is that it reduces the variations of
instantaneous transmit power, which eventually implies anincrease of power amplifier
efficiency. With this approach LTE is able to avoid the obstacles of OFDM in the aspect
of power consumption.

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D.OFDMA:
Often OFDMA and OFDM are used as synonymous. OFDMA allows the use of OFDM
modulation for multiple user access. Users can be allocated to any of the subcarriers in the
used frequency band to enable this. In addition, it allows a flexible and better scheduling
of resource allocation and services. Subcarriers are pooled to resource blocks to provide a
good applicability (12 subcarriers per time slot). These blocks can be scheduled to
different users as shown in figure 2. Furthermore certainenhancements or variations are
used in LTE and WiMAX, such as SOFDMA (Scalable OFDMA) and SC-FDMA (Single
Carrier - Frequency Division Multiple Access).
Fig.6: OFDMA Resource Block Scheduling
E.SOFDMA:
SOFDMA provides scalability support to OFDMA. Both OFDMA-based systems, LTE
and WiMAX support variable bandwidth sizes. The main goal of SOFDMA is to keep the
subcarrier spacing constant.

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F.SC-FDMA:
The basic obstacle of OFDM is high power consumption. The power consumption of the
data transmission is very crucial in the uplink where often mobile terminals are especially
used. For this reason, 3GPP LTE uses Single Carrier FDMA, which is also referred as
DFTS-OFDM (Discrete Fourier Transform Spread OFDM). SC-FDMA is a single carrier
modulation which is basically a normal OFDM with a DFT-based precoding. The main
advantage of this approach is that it reduces the variations of instantaneous transmit
power, which eventually implies anincrease of power amplifier efficiency. With this
approach LTE is able to avoid the obstacles of OFDM in the aspect of power
consumption.
G.MIMO:
MIMO (Multiple Input Multiple Output) is one of the fundamental technologies used
in the 4G networks which is already used in 802.11n (WLAN-n standard). The basic
principle behind this technology is the spatial multiplexing. Multiple antennas at the
sender and the receiver side are needed for this approach. The data stream is divided into
multiple smaller data streams in MIMO where in these smaller data streams are then sent
and received over multiple antennas. This approach takes advantage of the multi-path
propagation of radio signals and the peak data rates increase, because of the multiple
antennas. However, with the use of multiple antennas also the power consumption
increases. There are several different configurations for MIMO. The often used terms 4x4
(4 sending antennas, 4 receiving antennas), 4x2 or 2x2represent the MIMO configuration.
Similar approaches are SIMO (Single Input Multiple Output) which is often used in
battery powered User Terminals, MISO (Multiple Input Single Output) or the well-known
approach with one antenna on each side SISO (Single Input Single Output).
3.5Objectives
Due to the importance and the complication of the mobile wireless networks, such as the
WiMAX, UMTS and WiFi networks [7], an analysis study that aids in understanding the
mobility problems, mobility insights from requirements, parameters and configurations
in Mobile WiMAX network is presented in this research. The main objective focuses of
the research are as follows:
1. To analysis mobile WiMAX network with regards to network topology acquisition,
the base station and the main management messages that rules the mobility in
WiMAX systems.
2. To evaluate mobile WiMAX network by performing an actual handover process to a
new target base station.
3. To compare WiMAX performance with UMTS and WiFi wireless networks with
respect to Throughput, E-2-E Delay and Jitter.
3.6 Problem Analysis

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There are number of means to support mobility in communication devices such as
roaming, portability, and covering mobility with a faster speed (vehicle speed) [9].
However, one of the important concerns of mobility concept for communication devices is
how to motivate end users to use this technology, together with the emerging services for
mobile devices presented by the service provider e.g. using packet data for streaming
multimedia files.As there are many wireless networks technologies, there is a need to
gather and analyze information about these technologies to be filtered and collected in a
trendy presentation [10]. Communication devices such as smart phones and laptops
capabilities are getting more complex and emergent services that are supplied by the
network provider like streaming audio/video through packet data are more desirable [6].
More so, there are different methods behind the cutting edge of the overall system
performance for instance portability, full mobility and roaming. These methods often
differ among various network technologies as the mobility characteristics of each [10].
For the reasons above, it is vital to present a comprehensive study about mobile WiMAX
and awarenessof its mobility capabilities especially in the motion state andcomparing it
with other types of technologies. Consequentlyon one hand, knowing how WiMAX
supports infra-network mobility, and is it better Mn the other contemporary technologies?
And on the other hand, the handover mechanism as it is considered as an important
process included within mobile WiMAX technology is not intensively reviewed [11]. As
a matter of fact, researchers elaborated a handover in general or simulated the handover
homogeneously within one network [7, 12].
3.7Literature Review
Worldwide Interoperability for Microwave Access (WiMAX) is a new wireless
technology that can be used tobuild a wide coverage area networks with high Throughput
[13], and high security [14] as shown in Figure 1. It is intended for Wireless Metropolitan
Area Network (WMAN). WiMAX used to be the buzzword of wireless communication
industry for the last six years. It is able to provide Broadband Wireless Access (BWA) up
to 30 miles (50 km) for fixed stations, and 3-10 miles (5-15 km) for mobile stations [14].
IEEE authorized in 1999 a new working group known as 802.16. The group published its
first standard, IEEE 802.16a, in January 2003 [15]. The standards of WiMAX are
identified as 802.16-2004 (October 2004), 802.16e (December 2005), 802.16j (Jun 2009)
and 802.16m (still under development) [16]. Figure 2 shows the number of WiMAX
deployments over time per frequency.

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Figure 7:Cumulative number of WiMAX deployment per frequency
Daan P. have elaborated the different activities that occurred within the three important
organizations: The 802.16 working group of the IEEE for technology development and
standardization, the WiMAX forum for product certification and the ITU (International
Telcomunication Union) for international recognition. Theypresented a comprehensive
overview about the evolution of WiMAX in terms of standardization and certification.
Furthermore, they highlighted the steps that have been considered in cooperating with
the ITU to improve the international esteem of the technology. Finally, WiMAX trend
analysis has also been discussed.
Ray proposed a fast and simple scheme for Mobile Station (MS)-controlled handover
mechanism for mobile WiMAX environment. They suggested Received Signal Strength
(RSS) and path-loss formula in estimating MS distance from any neighboring Base
Stations (BS). The MS monitors the received signal strength that serves specificBS
periodically. The MS-controlled approach simulation of Mobile WiMAX network
outcomes show an observable reduction to handover latency accompanied by increase in
network scalability.

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CHAPTER-4
Methodology
Since the WiMAX is a new technology, it is difficult to get a realistic comparison
regarding a specific area of concern under specific circumstances within its architecture.
Because of the lack practical experience with WiMAX and most of the experiments or
simulations already done were focused on one specific area of concern. This research
contributes comprehend study on mobile WiMAX network handover process
performance.
The simulation of the handover process in mobile WiMAX is implemented using
QualNet 4.5.1 simulator. Three performance matrices selected to be used in the
experiment are: Throughput E-2-E delay, and Jitter within WiMAX environment. The
obtained results are compared with the results obtained from the handover simulation
process of WiMAX to WiFi network and WiMAX to UMTSnetwork. Finally, the Uplink
Channel Descriptor (UCD) and the Down Link Channel Descriptor (DCD) are simulated
within two different time intervals during the handover process. In this section the
research methodology is presented to illustrate how the research is carried out to meet its
objectives.
4.1QualNet Simulator
QualNet [19] is a state-of-the-art simulator for large, heterogeneous networks and the
distributed applications that execute on such networks. QualNet [20] is simulating
software that can be run on several platforms like Windows, Linux, 0 SX, and Solaris and
it is capable of simulating wireless networks such as WiMAX [21]. QualNet has been
used to simulate high-fidelity models of wireless networks with as many as 50,000 mobile
nodes [22]. It uses architecture analogues of the TCP/IP network protocol stack which is a
layered architecture.
The technology used in QualNet consists of 5 layers (top to bottom) as shown in Figure 3.
The layers that are adjacent in the protocol stack communicate using well defined
protocol. In general, the communication only occurs between adjacent layers (possible to
be altered by the developers) [23].

Dept of ECE Page 25
Figure 8:QualNet layer model
Figure 3 shows the QualNet layer model inwhich Constant Bit Rate (CBR) application
and IEEE 802.16e MAC are used in the simulation. CBR application is generally used to
simulate multimedia traffic (time critical traffic types). It can be configured to simulate a
large number of real network applications by mimicking their traffic pattern and by filling
traffic at a constant rate into the network. It can be accurately simulated by appropriately
configuring the CBR application in QualNet. The simulated traffic sources CBR is
generated using 4 mobile nodes performing handover process homogenously and
heterogeneously with two time intervals, 5 and 10 seconds (UCD, DCD).
4.2Performance Metrics
Performance metrics is used to measure and evaluate the handover processes
homogeneously and heterogeneously within WiMAX environment. Three parameters
have been selected for the evaluations which are Throughput, E-2-E and Jitter.
4.2.1Throughput
The average Throughput represented by: the ratio of total amount of data that reaches its
destination to the time taken for the data to transfer from the source to the destination. The
data packets received at the physical layer are sent to thehigher layers if they are destined for
this station. Throughputis usually described by bytes or bits per second (Bps or bps).
TraiTx _znenition
;nsws C BR)
Data Trannussiou
Rmrcui2 hmtols
IEEE so2.16o
R<~tr bE
reansnrission over
aonuinuu:ntion clu
nhlel

Dept of ECE Page 26
4.2.2 End-to-End (E-2-E) Delay
The average End-to-End (E-2-E) Delay is the time taken for a packet to be transmitted
across a network from source to destination. This metric describes the packet delivery time
whereas the lower the E-2-E Delay, the better the application performance. The E-2-E
Delay value is averaged over the number of packets. It is mathematically represented by the
following equation.
Total E-2-E delayAverage E - 2 - E delay = xo.a f packets received
4.2.3 Jitter
The Jitter is the deviation in the time among packets arriving at the destination side,
caused by network congestion, timing drift, or route changes. It signifies the Packets from
the source till they reach their destination with different delays. A packet's delays vary with
its location in the queues of the routers along the path between source and destination. This
location is not predictable due to network circumstances. Equation below describes the
Jitter calculation:
Jitter = Receptiom Time ofpacket(/)-Reception Time ofpacket(I-1)
4.3 Simulation Parameters
Various parameters have been used in all simulation scenarios to analyze the handover
behavior under specific circumstances both homogeneously and heterogeneously. The
simulation parameters that are used in this research are listed in Table 1. The speed of
mobile nodes during handover process is 8OKMPH; the size of the field is 1500m x
1500m. During the simulation, all nodes start performing handover from 0 second until the
time of simulation ends (25s).

Dept of ECE Page 27
4.4 Simulation Environments
Table2:SimulationParameters
The QualNet simulator v.4.5.1 has been used to simulate the proposed scenarios for
studying the handover process between WiMAX, WiFi and UMTS networks .UMTS and
WiFi are chosen as they are common networks used nowadays and their technologies are
almost similar. Therefore, it's possible to establish new connections between them
heterogeneously.
The simulation of the handover process between the mentioned homogeneous and
heterogeneous networks is conducted to evaluate the Throughput, E-2-E Delay and jitter. In
each simulation scenario, the UCD and DCD messages are modified within two time
intervals (5 and 10 seconds) during handover to find out which time interval performs
better in each performance metric. The Constant Bit Rate (CBR) application is used to
simulate the assumed scenarios in QualNet v.4.5.1
Parameter Val
ue
~5range radius (m) 100
0
AP range radius (m) 500
errain-dimensions (m) 1500,
15005-APdistance (m) 1200
requency band (GHZ) 2.4
Handover RSStrigger -78.0
Handover RSSmargin 3.0
Channel bandwidth (MHZ) 20
e duration (ms) 20
T size 2048
MS velocity [m.s-'] 20
BS Pt
transmit power
= Aeight(m)
20/5
AP Pt
transmit
power
=neBgnt(m)
20/1
.5
MS transmit power Pt= height(M) 15/1
.5Somulation time (s) 25
Traffic CB
R

Dept of ECE Page 28
Four different experiments are conducted to evaluate the WiMAX handover mechanism. The first
experiment is conducted to evaluate the average Throughput of the system during handover process.
The second experiment compares the difference in the inter packet arrival times at the receiver (jitter)
with respect to the total number of MS for every routing protocol. The purpose of the third experiment
is to analyze the E-2-E Delay of the system during handover process. Finally, the fourth experiment is
about comparing the time intervals of the UCD and DCD messages during handover process within
two time intervals (5 and 10 seconds), regarding to the three performance metrics just mentioned
above to find out which time interval performs the best during the handover process.
4 . 5 R e s u l t s
Results obtained from the handover simulation process are discussed in this section. The
Throughput, E-2-E Delay and Jitter of each simulated environment of the three (WiMAX WiMAX,
WiMAX-WiFi and WiMAX-UMTS) is discussed in the following sup-sections:
4.5.1Throughput Result
Average Throughput is the ratio of total amount of data that reaches its destination to the time
taken for the data to travel from the source to the destination. Figure 6 shows theaverage Throughput of
the three handover environment with respect to the number of moving nodes.The average Throughput
in WWAX-WiMAX handover is obviously the highest since it involves the same technology. In
another words, the similarity in the BS type is high which saves any extra management signaling.
WiMAX-UMTS comes in second, with slightly lower Throughput compared to WiMAX WiMAX.
WiMAX WiFi comes in last, with much lower Throughput compared to WiMAX-WiMAX and
WiMAX-UMTS. It is also observed that as the number of moving nodes increases, the average
Throughput slightly decreases. Figure 6 depicts that the WiMAX-WiFi has much lower Throughput
compared to the other two as a result of lower performance of the WiFi network compared with
WiMAX and UMTS. It is also recorded that the Throughput drops dramatically with moremoving
nodes due to the high load on the network with more nodes.
The system Throughput of WiMAX-WiMAX environment with variant values of UCD and DCD
messages. Two time interval (5 and 10s) is configured in each simulation run. In first run, the time
interval of UCD and DCD messages is 5seconds for each. In second run, the time interval is 10
seconds for each.
4.5.2End-to-End Delay Result
In general, the average of E-2-E Delay matrix for all simulation environments (WiMAX WiMAX,
WiMAX-UMTS and WiMAX-WiFi) increases as the number of MSs in the network increases (see
Figure 8). This is expected in wireless environments due to queuing delays at every hop node (BS or
AP). Neither the WiMAX-WiMAX nor the WiMAX-UMTS utilize their effects on average E-2-E
Delay for traffic; hence it appears to be minimal. However, the average E-2-E Delay for the
different numbers of MSs with the WiMAX-WiMAX and WiMAX-UMTS are lower than with
the WiMAX-WiFi under all scenarios. Similar to the result in Section A, the WiMAX-WiMAX

Dept of ECE Page 29
and WiMAX-UMTS handover give the best performance while the WiMAX-WiFi gives the worst
performance due to WiFi network lower performance compared with WiMAX and UMTS in
addition to the variety in the technology specifications quality.
4.5.3 Jitter Result
The simulation result of the overall mobility Jitter performance with various number of moving
MSs for all simulated environments is shown in Figure 10. The WiMAX-WiMAX and WiMAX-
UMTS environments perform with lower Jitter compared with WiMAX-WiFi environment due to
the variance in the technology specifications quality.

Dept of ECE Page 30
CHAPTER-5
SWOT ANALYSIS - 4G With Wimax:
Considering 4G characteristics, expected scenarios and market trends, we can find out
strengths, weaknesses, opportunities and threats of 4G with better understandings. The
lists and findings follow.
Strengths in 4G:
 4G visions take into account installed base and past investments
 Strong position of telecommunications vendors expected in the marketplace.
 Faster data transmission and higher bit rate and bandwidth, allow more
business applications and commercialization
 Has advantage for personalized multimedia communication tools
Weakness in 4G:
_ No large user community for advanced mobile data applications yet.
_ Growing divergence between telecommunications vendors and operators.
_ Not possible to offer full internet experience due to limited speed and bandwidth.
_ Comparatively higher cost to use and deploy infrastructure compared fast mobile
generation.
Opportunities in 4G:
 Evolutionary approach may yield opportunities for the 4G
 Emphasis on heterogeneous networks capitalizes on past investments
 Strategic alliance and coalition opportunities with traditional non-
telecommunication industries
 Sophisticated and mature commercialization of 4G technology would encourage
more applications of e-commerce and m-commerce
 Worldwide economy recover stimulates consumption and consumer
confidence, therefore bring in opportunities for telecommunication sections
 It is expected and predicted that consumers will continue to replace handsets
with newer technology at a fast rate.
 Desirable higher data capacity rates, the growth opportunity for 4G is very bright and
hopeful.
Threats in 4G:

Dept of ECE Page 31
 Faster rate of growth and developments in other region
 Since 3G mobile is still in the market, it squeezes the market competition in the mobile
industry.
5.1 WI-MAX Security Features
This section discusses the security mechanisms included in IEEE 802.16-2004, IEEE
802.16e-2005, IEEE 802.16-2009, and IEEE 802.16j-200915; it illustrates their functions and
provides a foundation for the security recommendations in Section 4. The IEEE 802.16
standards specify two basic security services: authentication and confidentiality.
Authentication involves the process of verifying the identity claimed by a Wi-MAX device.
Confidentiality is limited to protecting the contents of Wi-MAX data messages so that only
authorized devices can view them. IEEE 802.16e-2005 and IEEE 802.16-2009 share the same
authentication and confidentiality mechanisms; they both support user authentication and
device authentication.
The IEEE 802.16 standards do not address other security services such as availability
and confidentiality protection for wireless management messages 16; if such services are
required, they must be provided through additional means. Also, while IEEE 802.16 security
protects communications over the WMAN link between an SS/MS and a BS, it does not
protect communications on the wired operator network behind the BS. End-to-end (i.e.,
device-to-device) security is not possible without applying additional security controls not
specified by the IEEE standards.
Wi-MAX systems provide secure communications by performing three steps:
authentication, key establishment, and data encryption. Figure 3-1 is a high-level overview of
the security framework. The authentication procedure provides common keying material for
the SS/MS and the BS and facilitates the secure exchange of data encryption keys that ensure
the confidentiality of Wi-MAX data communications. The remainder of this section explains
the basics of the Wi-MAX security framework, authentication, key establishment, and data
encryption.

Dept of ECE Page 32
Figure 9:WiMAX Security Framework
5.2 Security Associations
A security association (SA) is a shared set of security parameters that a BS and its SS/MS use
to facilitate secure communications. Similar in concept to Internet Protocol Security
(IPSec),18 an SA defines the security parameters of a connection, i.e., encryption keys and
algorithms. SAs fall into one of three categories: authorization, data (for unicast19 services),
and group (for multicast20 services). A distinct SA is established for each service offered by
the BS. For example, a uncast service would have a unique data encryption SA, whereas a
multicast service would have a unique group SA. Authorization SAs facilitate authentication
and key establishment to configure data and group SAs. Authorization SAs contain the
following attributes: X.509 certificates. X.509 digital certificates allow Wi-MAX
communication components to validate one another. The manufacturer’s certificate is used
for informational purposes, and the BS and SS/MS certificates contain the respective devices’
public keys. The certificates are signed by the device manufacturer or a third-party
certification authority.
Authorization key (AK). AKs are exchanged between the BS and SS/MS to authenticate one
another prior to the traffic encryption key (TEK) exchange. The authorization SA includes an
identifier and a key lifetime value for each AK.

Dept of ECE Page 33
Key encryption key (KEK). Derived from the AK, the KEK is used to encrypt TEKs during
the TEK exchange.
Message authentication Keys Derived from the AK, the message authentication keys
validate the authenticity of key distribution messages during key establishment. These keys
are also used to sign management messages to validate message authenticity.
Authorized data SA list. Provided to the SS/MS by the BS, the authorized data SA list
indicates which data encryption SAs the SS/MS is authorized to access.
Data SAs establish the parameters used to protect unicast data messages between BSs
and SSs/MSs. Data SAs cannot be applied to management messages, which are never
encrypted. A data SA contains the following security attributes:
SA identifier (SAID). This unique 16-bit value identifies the SA to distinguish it from other
SAs.
Encryption cipher to be employed. The connection will use this encryption cipher
definition to provide wireless link confidentiality.
Traffic encryption key (TEK).
TEKs are randomly generated by the BS and are used to encrypt Wi-MAX data
messages. Two TEKs are issued to prevent communications disruption during TEK rekeying;
the first TEK is used for active communications, while the second TEK remains dormant.21
Data encryption SA type indicator.
This indicator identifies the type of data SA. There are three types: Primary
SA. This SA is established as a unique connection for each SS/MS upon initialization with
the BS. There is only one primary SA per SS/MS.
Static SA. This SA secures the data messages and is generated for each service defined by
the BS.
Dynamic SA. This SA is created and eliminated in response to the initiation and termination
of specific service flows. Group SAs contain the keying material used to secure multicast
traffic. Group SAs are inherently less secure than data SAs because identical keying material
is shared among all members of a BS’s group. Group SAs contains the following attributes

Dept of ECE Page 34
5.3 SECURITY THREATS :
A. WiMAX Security Attacks
Jamming and packet scrambling are the general kinds of attacks that can most
affect WiMAX's physical layer. Signals in the lower frequencies that cross or are in
close proximity to the WiMAX antenna can produce second and third harmonic waves
that interfere and can overload the WiMAX signal. Because WiMAX is transmitted
over frequency bands that are licensed, unintentional jamming is rare. Taking a
spectrum analysis at intervals can mitigate constant jamming, whether malicious or not
[11]. Within the MAC Layer of the network stack, digital certificates work very well
for establishing the identity of a mobile station to a base station.
However, a simple one-way authentication could allow an opportunity for
intruders to create a rogue base station and snoop traffic. Authentication using EAP-
TLS will enable both the base station and the mobile station to use X.509 certificates
to establish their legitimacy. Two of the most destructive attacks can be MITM (Man
in the middle attack) and DoS (Denial of Service attack) attacks.
Power efficiency:
Both LTE and WiMAX offer power ving mechanisms. They can be both sent into an
offtte where less or even no power is needed. LTE can also -n the transmitter off while
having a call when there are iger breaks. Also LTE uses SC-FDMA in the uplink, iich
is more power efficient than OFDMA. This makes bile devices use less power, which
increases their ttery life.
The following threats affect all WiMAX systems:
RF jamming:
All wireless technologies are susceptible to RF jamming attacks. The threat arises from an
adversary introducing a powerful RF signal to overwhelm the spectrum being used by the
system, thus denying service to all wireless nodes within range of the interference. RF
jamming is classified as a DoS attack. The risk associated with this threat is identical for
IEEE 802.16-2004, IEEE 802.16e-2005, and IEEE 802.16-2009 WiMAX systems.
Scrambling:
Scrambling attacks, which are the precise injections of RF interference during the
transmission of specific management messages, affect all wireless systems. These attacks
prevent proper network ranging and bandwidth allocations with the intent to degrade overall

Dept of ECE Page 35
system performance [Nas08]. Scrambling attacks are more difficult to identify than jamming
attacks because they are engaged for short time periods and are not a constant source of
interference. The risk associated with this threat is identical for IEEE 802.16-2004, IEEE
802.16e-2005, and IEEE 802.16-2009.
Subtle management message manipulation:
Exploitation of unauthenticated management messages can result in subtle DoS, replay, or
misappropriation31 attacks that are difficult to detect. These attacks spoof management
messages to make them appear as though they come from a legitimateor SS/MS, allowing
them to deny service to various nodes in the WiMAX system. A water torturattack is an
example of a subtle DoS in which an adversary drains a client node’s battery by sending a
constant series of management messages to the SS/MS [Joh04]. IEEE 802.16e-2005 and
IEEE 802.16-2009 provide integrity protection for certain unicast management messages
following initial network registration with an appended integrity protection digest. All other
IEEE 802.16e-2005 and IEEE 802.16-2009 management messages, and all IEEE 802.16-
2004 management messages, are susceptible to attacks involving manipulation. Man-in-the-
middle. Man-in-the-middle attacks occur when an adversary deceives an SS/MS to appear as
a legitimate BS while simultaneously deceiving a BS to appear as a legitimate SS/MS. This
may allow an adversary to act as a pass-through for all SS/MS communications and to inject
malicious traffic into the communications stream. An adversary can perform a man-in-the-
middle attack by exploiting unprotected management messages during the initial network
entry process. This is because the management messages that negotiate an SS’s/MS’s security
capabilities are not protected. If an adversary is able to impersonate a legitimate party to both
the SS/MS and BS, an adversary could send malicious management messages and negotiate
weaker security protection between the SS/MS and BS [Han06]. This weaker security
protection may allow an adversary to eavesdrop and corrupt data communications. Mandating
the use of AES-CCM in IEEE 802.16e-2005 and IEEE 802.16-2009 helps mitigate this attack
because it appends a unique value to each data packet, which, in turn, prevents the man-in-
the-middle traffic relays between BS and SS/MS. IEEE 802.16-2004 does not offer adequate
protection against man-in-the-middle attacks Eavesdropping. Eavesdropping occurs when
an adversary uses a WiMAX traffic analyzer within the range of a BS or SS/MS. The large
operating range of WiMAX networks helps to shield eavesdroppers from detection;
eavesdropping mitigation relies heavily on technical controls that protect the confidentiality

Dept of ECE Page 36
and integrity of communications. The adversary may monitor management message traffic to
identify encryption ciphers, determine the footprint
of the network, or conduct traffic analysis regarding specific WiMAX nodes. Data messages
collected during eavesdropping can also be used to decipher DES-CBC encryption; however,
AES provides robust data message confidentiality that cannot be circumvented through
eavesdropping. The risk associated with eavesdropping management messages is identical for
IEEE 802.16-2004, IEEE 802.16e-2005, and IEEE 802.16-2009. The risk associated with
eavesdropping data messages is significant for IEEE 802.16-2004 systems due to weak
encryption. IEEE 802.16e-2005 and IEEE 802.16-2009 systems offer the stronger AES
cipher to protect data messages from eavesdropping.

Dept of ECE Page 37
CHAPTER-6
Countermeasures
This section presents countermeasures that may be used to reduce or mitigate the risks
inherent to WiMAX systems. These countermeasures do not guarantee security and cannot
prevent all possible attacks. The optimum security design is a dynamic intersection of threat
risk and the cost of countermeasures that will change in response to technology.
Organizations should implement countermeasures commensurate with their acceptable level
of risk.
The WiMAX management, operational, and technical countermeasures described in the
following sections take an approach similar to that of NIST SP 800-48 Revision 1, Guide to
Securing Legacy IEEE 802.11 Wireless Networks [Sca08]. IEEE 802.11 and IEEE 802.16
share many management and operational controls but strongly differ in their technical
controls. WiMAX systems should leverage the countermeasures found in this Special
Publication, in FIPS PUB 199, and in NIST SP 800-53. FIPS PUB 199, Standards for
Security Categorization of Federal Information and Information Systems establishes three
security categories—low, moderate, and high—based on the potential impact of a security
breach involving a particular system [NIS04]. NIST SP 800-53, Recommended Security
Controls for Federal Information Systems and Organizations, provides recommendations for
minimum management, operational, and technical security controls for information systems
based on the FIPS PUB 199 impact categories [NIS09]. Regardless of a system’s sensitivity
classification, WiMAX security should be incorporated throughout the entire lifecycle of
WiMAX solutions [Kis08].
6.1 Management Countermeasures :
Management countermeasures generally address any problem related to risk, system planning, or
security assessment by an organization’s management. Organizations should develop a wireless
security policy that addresses WiMAX technology. A security policy is an organization’s foundation
for designing, implementing, and maintaining properly secured technologies. WiMAX policy should
address the design and operation of the technical infrastructure and the behavior of users.
Policy considerations for WiMAX systems should include the following:
Roles and responsibilities
 Which users or groups of users are authorized to use the WiMAX system

Dept of ECE Page 38
 Which office or officer provides the strategic oversight and planning for all WiMAX
technology programs
 Which parties are authorized and responsible for installing and configuring WiMAX
equipment
WiMAX infrastructure
 Physical security requirements for WiMAX assets .
 The use of standards-based WiMAX system technologies.
 Types of information permitted over the WiMAX system, including acceptable use
guidelines .
 How WiMAX transmissions should be protected, including requirements for the use
of encryption and for cryptographic key management .
WiMAX client device security
 Conditions under which WiMAX client devices are allowed to be used and operated
 Standard hardware and software configurations that must be implemented on WiMAX
devices to ensure the appropriate level of security
WiMAX security assessments
 Frequency and scope of WiMAX security assessments
 Standardized approach to vulnerability assessment, risk statements, risk levels, and
corrective actions .
6.2 Operational Countermeasures:
Operational countermeasures include controls that are executed by people, e.g., personnel
security, physical environment protection, configuration management, security awareness and
training, and incident response. These controls are documented in a system security plan
(SSP) which should be maintained by all parties involved with WiMAX system operations.
SSPs are living documents that provide an overview of the security requirements of a system
and describe the controls in place to meet those requirements; this includes all system
hardware and software, policies, roles and responsibilities, and other documentation

Dept of ECE Page 39
materials. Documentation itself is a security control, as it formalizes security and operational
procedures to a given system.
Physical security is fundamental to ensuring that only authorized personnel have access to
WiMAX equipment. Physical security includes measures such as physical access control
systems, personnel security and identification, and external boundary protection. For
example, integrating Federal personal identity verification (PIV)35 into physical access
controls can reduce the risk of unauthorized access to WiMAX systems.36 WiMAX system
administrators and users should receive training to address the specific challenges and threats
to wireless technologies. While it is difficult to prevent unauthorized users from attempting to
access a WiMAX system because of its expansive coverage area, the use of additional
security mechanisms may help prevent the theft, alteration, or misuse of WiMAX
infrastructure components.
WiMAX operates on licensed or unlicensed RF spectrum. The most prevalent spectrum
used to accommodate WiMAX is the 2.5 GHz licensed range, but WiMAX solutions are also
viable across several unlicensed spectrum ranges. Organizations should understand the
implications of spectrum allocation as it impacts system availability. Due to the proliferation
of unlicensed wireless technologies, interference may become an implementation obstacle
when operating in unlicensed spectrum. Regardless of which spectrum frequency is used,
organizations should use counter-interference technologies37 in addition to site surveys to
ensure system availability.
Prior to deployment, site surveys construct the foundation for a WiMAX system’s design
to ensure system availability. Long distance radio transmissions should be tailored and
optimized for RF obstacles and interference sources. Site surveys help limit range to provide
an organization operational awareness of a system’s coverage area.
Site survey tools include terrain maps, global positioning systems, RF propagation
models, spectrum analyzers, packet analyzers, and additional tools which provide a more
thorough understanding of the environment’s RF landscape. Conducting a WMAN site
survey requires specialized skills, and it is typically provided as part of the overall vendor
solution. Organizations should, at a minimum, involve themselves in the site survey process
and document its findings in the system security plan.

Dept of ECE Page 40
As with all wireless technologies, operational countermeasures may not provide protection
against general wireless threats such as DoS, eavesdropping, man-in-the-middle, and message
replay. Operational controls often require highly specialized expertise and rely upon both
management and technical controls
6.3 Comparisons of WiMAX and LTE:
Parameters WiMAX LTE
Release and
Deployment
2005 2009
Generation 4G(Wimax 802.16m) 4G(Advanced LTE)
Transfer rates 46 Mbps in the downlink and up
to 4 Mbps in
the uplink
300 Mbps in the downlink
and 75 Mbps
in the uplinkPower efficiency Both offer power saving mechanisms. They can be both sent into
an off-state where less or
even no power is neededQuality of service Frame is separated in a downlink
and an uplink
subframe that allocates resources
for different
users
LTE frames don't separate
their frames in
uplink and downlink
subframes.
Security Concerning security aspects both, LTE and WiMAX, are on the
same level
Physical layer DL:OFDMA
UL:OFDMA
DL:OFDMA
UL:SCFDMA
Duplex mode TDD(Time Division Duplex) TDD & FDD(Time &
Frequency
Division Duplex)User mobility 60-120 kmps Up to 350kmps
Coverage Up to 50km Up to 100km
Channel bandwidth 3.5,5,7,8.75,10MHz 1.4,3,5,10,15,20 MHz
Spectral efficiency DL:1.91bps/Hz(2*2)
UL:0.84 bps/Hz(1*2)
DL:1.91bps/Hz(2*2 )
UL:0.72 bps/Hz(1*2 )
Latency Link layer:about 20ms
Handoff:about 35-50ms
Link layer:< 20ms
Handoff:about:<50ms

Dept of ECE Page 41
VoIP capacity 20 Users per sector/MHz(TDD) 80 Users per sector z D D )
Other qualities Full IP-based architecture,3G compatible, QoS support
Table 3:Comparisons of WiMAX and LTE
7. Discussion:
The main focus is to investigate the handover process in Mobile WiMAX in terms of its
rules and address management and the main issues related to it. There is a limited related
works that investigate the handover scenarios in networks' simulation analysis. They
concentrate more on the transportation of subscribers (Mobile Stations) within WiMAX
environment and with another environments (e.g. UMTS or WiFi), and suggest other
fundamentals like scheduling and QoS as future works.
Two of the most important requirements for wireless communication technologies are to
be applicable and universally desirable. Mobile WiMAX 802.16e handover mechanism
analysis is the main target for this research. The focal point here is to introduce a complete
understanding about handover process in WiMAX network, as it is considered as the most
important process to achieve mobility within wireless networks. Work evaluation has been
done by simulating handover process with different situations homogeneously and
heterogeneously. The main task of the simulation process is to determine what parameters
are affected during handover process in mobile networks homogeneously within WiMAX
environment and heterogeneously to UMTS and WiFi networks.
The results show the ability to evaluate the performance of handover procedure within
WiMAX and the other networks that have been chosen for this research. Based on the
obtained results, a comparison among the three different networks has identified the best
environment to establish a "handover".
Regarding to channel descriptor, the purpose of the DCD messages is to specify the
characteristics of a given downlink physical channel. The BS transmits them at a given
interval, which can have a maximum value of 10 seconds. It's the same for UCD, in that it
specifies the characteristics of the uplink channel and is transmitted at a given interval,
which cannot exceed 10 seconds.
The WiMAX-WiMAX case has been simulated using two time intervals (5 and 10) seconds
under the three differential matrices (Throughput, E-2-E Delay and jitter) expecting that the
time interval 5s will achieve the best results due to the short time it takes to update the
current information compared to 10s.

Dept of ECE Page 42
8.Conclusion and Future Work
We discuss the simulation results of the handover process over WiMAX WiMAX,
WiMAX UMTS and WiMAX WiFi environments/networks. The simulation scenarios are
simulated to compare the results of each environment's behavior with handover process
using the QualNet simulator v4.5.1. The environment (WiMAX-WiMAX) has shown
substantial enhancement of the system Throughput, reduction of E-2-E delay, and reduction
of Jitter. This is mainly due to the similarity in the BS type which saves any extra
management signaling. For example, between WiMAX BS and UMTS BS, the management
messages signaling require longer time compared with WiMAX WiMAX BSs.
In addition, the best environment (WiMAX-WiMAX) is simulated with various values of
the time intervals of UCD and DCD management messages as a deep analysis. However, all
related simulation results show that the shorter time interval of both UCD and DCD
messages improves the overall network performance and the handover process.
The handover process of mobile WiMAX to improve its performance in terms of Delay and
moving speed. Thus, the handover optimization in mobile WiMAX is the recommendation
for future work.
9.References
[1] IEEE802.16 Working Group. "IEEE Standard for Local andMetropolitan Area Networks,
Part16: Air interface for fixedbroadband wireless access systems,"IEEE Std802 (2004).
L. M. Carlberg, and A Dammander, "WiMAX-A study of mobility and a MAC-layer
implementation in GloMoSim,"Master'
s Thesis in Computing Science (2006)
[2] Anita Garhwal, ParthaPratim Bhattachary "Performance Enhancement of WiMAX
System using Adaptive Equalizer" Department of Electronics and Communication
Engineering, Faculty ofEngineering and Technology Mody Institute of Technology & Science
(Deemed University).
[3] Jeffery G. Andrews, ArunabhaGhosh, RiasMuhamed, "Fundamentals of WiMAX:
Understanding Broadband Wireless Networking", Prentice Hall, 2007.
[4] Igor Bilogrevic, MurtuzaJadliwala and Jean-Pierre Hubaux "Security Issues in Next
]Applications (Al), LC E P F L, Lausanne, Switzerland 2010.
[5] Q. B. Mussabbir, "Mobility management across converged IP-based heterogeneous
access networks," PhD Thesis. School of Engineering and Design, Brunel Universit (2010).

Dept of ECE Page 43
[6] International Telecommunication Union (ITU), "Broadband mobile communications
towards a converged world," Micworkshop on shaping the future mobile information
society, Seoul. 2004.
[7] F. Akyildiz, J. Xie and S. Mohanty. "A survey of mobility management in next-
generation all-IP-based wireless systems," II ireless Communications, IEEE 11.4
[8] Z. Becvar, P. Mach and R. Bestak, "Initialization of handover procedure in WiMAX
networks," ICT-MobileSummit 2009 Conference Proceedings, 2009.
[9] I. Liao, Q. Qi, X. Zhu, Y. Cao, and T. Li, "Enhanced MS handoff mechanism for QoS
support over heterogeneous network," The Computer Journal 53.10 (2010): 1719-1737.
[10] I.R. Santhi and G. S. Kumaran, "Migration to 4 G: Mobile IP based solutions,"
Telecommunications, 2006. AICT-ICIW'06. International Conference on Internet and
Web Applications and Services/Advanced International Conference on. IEEE, 2006.
WiMAX.com, "What is WiMAX," WMax.com Broadband Solutions, Inc. 2011.
<http://www.wimax.com/general/what-is-wi=>
[11] A. Shami, M. Maier, and C. Assi. Broadband Access Networks: Technologies and
Deployments. Springer Verlag, 2009.
[12] F. Muratore.UMTS: Mobile communications for the future. John Wiley & Sons, Inc.,
2000.
[13] QualNet 4.5 Programmer's Guide, Scalable Network Technologies, Inc., 2008.
<http://www.eurecom. fr/-chenj lQuaINet03.pdf.>
[14] QualNet Product Family, Scalable Network Technologies, Inc., 2010.
<http://www.scalable-networks.com/pdf/QualNet

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