JOURNAL OF INFORMATION, KNOWLEDGE AND RESEARCH IN
ELECTRONICS AND COMMUNICATION ENGINEERING
PERFORMANCE ANALYSIS OF WiMAX NETWORK
WITH ADVANCE ANTENNA TECHNIQUE (MIMO)
1 DIPEN
1
G. PATEL, 2 PROF. ANOOP SINGH POORINIA,
Student, M.Tech. Rajasthan Institute of Engg. & Tech. Jaipur ,Rajasthan, India
2 Director, Rajasthan Institute of Engg. & Tech. Jaipur, Rajasthan. India
[email protected], [email protected]
ABSTRACT: This paper present the performance analysis of WiMAX network with multiple antenna technique
(MIMO), in which WiMAX is a second generation protocol that allows for more efficient bandwidth use,
interference avoidance and is intended to allow higher data rates over long distances. WiMAX (Worldwide
Interoperability for Microwave Access) is a telecommunication technology that provides wireless transmission
of data and it is a great alternative to fixed broadband connections such as cable or DSL. The technology is
based on the IEEE 802.16 standard (called Broadband Wireless Access). WiMAX is led by the WiMAX Forum,
a global organization of manufacturers and operators who share knowledge and developments to ensure
compliance and international compatibility in WiMAX technology as per the IEEE 802.16 standard. This paper
is on of the foot steps towards technical contribution in the world of wireless communication. The advanced
multiple antenna technique makes it very conducive to other technologies, such as antenna diversity
implementation ubiquitous. This paper starts with the introduction to WiMAX and comparative analysis with
other wireless techniques. In the second phase, the performance analysis of WiMAX system is discussed. In the
third phase, the physical layer of WiMAX system with MIMO technique has been elaborated and analyzed with
simulation results.
KEYWORDS- WiMAX, MIMO, AAS, Wi-Fi, 4G
1. INTRODUCTION
The increasing demand in wireless services is
resulting from use of digital networks as a next
generation wireless communication networks with
higher capacity. The increased reliance on computer
networking and the internet has resulted in a wider
demand for connectivity to be provided “any where,
any time” leading to a rise in the requirements for
higher capacity and high reliability broadband
wireless telecommunication systems. WIMAX may
be seen as the fourth generation (4G) of mobile
systems as the convergence of cellular telephony,
computing, internet access, and potentially many
multimedia applications become a real fact. WIMAX
is considered today the most interesting opportunity,
able to provide radio coverage distances of almost
kilometers and data trough put up to 70 Mbps, and
complete wired network architectures, ensuring a
flexible and cheap solution for the last-mile, the
interoperability is a very strategic issue, on which
equipment cost and volume of sales will be based.
Operators will not be bound to a unique equipment
supplier, as the radio base stations will be able to
interact with terminals produced by different
suppliers. Operators can benefit of suppliers’
competition in terms of costs and innovation.
2. RELATIONSHIP WITH OTHERWIRELESS
TECHNOLOGIES
Wireless access to data networks is expected to be an
area of rapid growth for mobile communication
systems. The huge uptake rate of mobile phone
technologies, WLANs and the exponential growth
that is experiencing the use of the Internet have
resulted in an increased demand for new methods to
obtain high capacity wireless networks.
WiMAX is expected to have an explosive growth, as
well as the Wi-Fi, but compared with the Wi-Fi
WiMAX provides broadband connections in greater
areas, measured in square kilometers, even with links
not in line of sight. For these reasons WiMAX is a
MAM, highlighting that “metropolitan” is referred to
the extension of the areas and not to the density of
population, But Wi-Fi and WiMAX are not
competing technologies. While WiMAX can provide
high capacity internet access to residences and
business seats, Wi-Fi allows to extension of such
connections inside the corporate sites buildings.
In any case, both WLAN and cellular mobile
applications are being widely expanded to offer the
demanded wireless access. However, they experience
several difficulties for reaching a complete such as
bandwidth, coverage area, and infrastructure costs.
As shown in fig.2, Wi-Fi provides a high data rate,
but only on a short range of distances and with a slow
movement of the user. On ht e other hand, cellular
offers larger ranges and vehicular mobility, but
instead, it provides
ISSN: 0975 – 6779| NOV 11 TO OCT 12 | VOLUME – 02, ISSUE - 01
Page 250
JOURNAL OF INFORMATION, KNOWLEDGE AND RESEARCH IN
ELECTRONICS AND COMMUNICATION ENGINEERING
Fig 1 Comparative Analysis
more as backhaul for Wi-Fi and other WLAN
technologies.
In order to provide interoperability among the various
technologies the WiMAX forum, an industry body
founded in 2001 to promote conformance to
standards
this
wireless
network.
WiMAX
developments have been moving forward at a rapid
pace [8]. The initial standardization efforts in IEEE
802.16.Standards for Fixed WiMAX (IEEE 802.16.
Standards for Fixed WiMAX (IEEE802.16-2004)
were announced as final in 2004, followed by Mobile
WiMAX (IEEE 802.16e) in 2005.[3]
In Europe, the standards for wireless MAMs were
formalized under the ETSI as HiperMANs. There
were also based on IEEE 802.16 standards but did
not initially use the same parameters (such as
frequency or number of sub-carriers). These were
later harmonized with the WiMAX[1]
Lower data rates, and requires high investments for
its deployment. WiMAX tries to balance this
situation.[7]
WiMAX fills the gap between Wi-Fi and cellular,
thus providing vehicular mobility, and high service
areas and data rates.
Fig 3 WiMAX Standards Evolution
Fig 2 Relationship with other wireless technologies
3. WiMAX STANDARDS
WiMAX is a broadband wireless standard that enjoys
widespread support from both the computer and
telecom industries worldwide, making this
technology particularly cost effective. Converged
networks will likely connect users via the least-cost
bandwidth path that service their usage demands. In
rural areas without other broadband options,
WiMAX-to-the-home connectivity will likely play
the major role in providing “multi-play” services
including voice, data and video. In urban
environments the role of fixed-WiMAX will likely be
Standards. The IEE 802.16d standards provide for
fixed and nomadic access, while the 802.16e
standards also provide mobility up to speeds of 120
kilometers per hour.[9]
4. WiMAX ARCHITECTURE
Figure 4 shows IEEE 802.16 Network Architecture
BS (Base Station) and SSs (Subscriber Stations) All
data traffic goes through the BS, and the BS control
the allocation of bandwidth on the radio channel.
During a communication, all the information coming
from a SS go to the BS and are retransmit to the right
SS. Base stations (BS) can handle thousands of
subscriber stations (SS).[8]
ISSN: 0975 – 6779| NOV 11 TO OCT 12 | VOLUME – 02, ISSUE - 01
Page 251
JOURNAL OF INFORMATION, KNOWLEDGE AND RESEARCH IN
ELECTRONICS AND COMMUNICATION ENGINEERING
Fig 4 WiMAX Architecture
Two type of link are defined:
• The downlink: From the BS to the SS.
• The uplink: From the SS to the BS.
A .WiMAX actually can provide two forms of wireless
service
• There is the non-line-of-sight - Wi-Fi sort of
service, where a small antenna on the computer
connects to the tower. In this mode, WiMAX uses a
lower frequency range -- 2 GHz to 11 GHz (similar
to Wi-Fi).Lower wavelength transmissions are not as
easily disrupted by physical obstructions -- they are
better able to diffract, or bend, around obstacles.
• There is line of sight service, where a fixed dish
antenna points straight at the WiMAX tower from a
rooftop or pole. The line-of-sight connection is
stronger and more stable, so it's able to send a lot of
data with fewer errors. Line-of-sight transmissions
use higher frequencies. At higher frequencies, there
is less interference and lots more bandwidth.
5. WiMAX TOPOLOGIES
The IEEE 802.16 standard defines two possible
network topologies
• PMP (Point-to-Multipoint) topology
• Mesh topology or Mesh mode
Fig 5 WiMAX PMP Topologies
The main difference between the two modes is the
following: in the PMP mode, traffic may take place
only between a BS and its SSs, while in the Mesh
mode the traffic can be routed. Through other SSs
until the BS and can even take place only between
SSs. PMP is a centralized topology where the BS is
the centre of the system while in Mesh topology it is
not. The elements of a Mesh network are called
nodes, e.g. a Mesh SS is a node. In Mesh topology,
each station can create its own communication with
any other station in the network and is then not
restricted to communicate only with the BS. Thus, a
major advantage of the Mesh mode is that the reach
of a BS can be much greater, depending on then
number of hops, until the most distant SS. On the
other hand, using the Mesh mode brings up the now
thoroughly studied research topic of ad hoc (no fixed
infrastructure) network routing.[11]
When authorized to a Mesh network, a candidate SS
node receives a 16-bit Node ID (Identifier) upon a
request to an SS identified as the Mesh BS. The Node
ID is the basis of node identification. The Node ID is
transferred in the Analysis of MIMO based WiMAX
Simulation For Next Gen Wireless Communication
Mesh sub header of a
Fig 6 WiMAX Mesh Topology
Generic MAC frame in both uncast and broadcast
messages. First WiMAX network deployments are
planned to follow mainly PMP topology. Mesh
topology is not yet part of a WiMAX certification
profile (September 2006).[5] It has been reported
that some manufacturers are planning to include the
Mesh feature in their products, even before Mesh is
in a certification profile.
6. SILENT FEATURE OF WIMAX
A. IP-based architecture
Wi-MAX defines a flexible all-IP-based network
architecture that allows for the exploitation of all the
benefits of IP. The reference network model calls for
the use of Ip-based protocols to deliver end-to-end
functions, such as QoS, security and mobility
management.
B. Very high peak data rates.
WiMAX is capable of supporting very high peak data
rates. Provide high-speed Internet access to home and
business subscribers, without wires as high as
ISSN: 0975 – 6779| NOV 11 TO OCT 12 | VOLUME – 02, ISSUE - 01
Page 252
JOURNAL OF INFORMATION, KNOWLEDGE AND RESEARCH IN
ELECTRONICS AND COMMUNICATION ENGINEERING
70Mbps when operation using a 10-66GHz wide
spectrum.
C. Large coverage area
Allows communications over long distances than
WiFi, and a greater bandwidth means it provides
wide coverage and high speed compared to Wi-Fi.
Theoretically Cover approximately 40 ~ 50 Km (30
miles)
D. Orthogonal frequency division multiple access
(OFDMA)
Mobile WiMAX uses OFDM as a multiple-access
technique, where by different users can be allocated
different subsets of the OFDM tones. OFDMA
facilitates the exploitation of frequency diversity and
multi user diversity to significantly improve the
system capacity.
E. Adaptive modulation & coding (AMC)
WiMAX supports a number of advanced signal
processing techniques to improve overall system
capacity. These techniques include adaptive
modulation and coding, spatial multiplexing, and
multi user diversity.
F. Link-layer retransmissions
For connections that require enhanced reliability,
WiMAX supports automatic retransmission requests
(ARQ) at the link layer. ARQ enabled connections
require each transmitted packet to be acknowledged
by the receiver. Unacknowledged packets are
assumed to be lost and are retransmitted.
G. Support for advanced antenna techniques
The WiMAX solution has a number of hooks built
into the physical-layer design, which allows for the
use of multiple-antenna techniques. WiMAX offers
very high spectral efficiency and variety of radiation
patterns, particularly when using
higher order
MIMO solutions.[4]
H. Quality-of-service support
The WiMAX MAC layer has a connection-oriented
architecture. WiMAX has a very flexible MAC layer
that can accommodate a variety of traffic types,
including voice, video and multimedia and provide
strong QoS.
I.OFDM-based physical layer
The WiMAX physical layer is based on OFDM,
which is an elegant and effective technique for
overcoming multipath distortion.
7. WiMAX OPERATION
WiMAX could be used to set up a back-up or even
primary communications system that would be
difficult to destroy with a single, pinpoint attack
Figure7 shows WiMAX operation and gives idea
about how WiMAX works. A cluster of WiMAX
transmitters would be set up in range of a key
command center but as far from each other as
possible. Each transmitter would be in a bunker
hardened against bombs and other attacks. No single
attack could destroy all of the transmitters, so the
officials in the command center would remain in
communication at all times. WiMAX system consists
of two parts:
A.WiMAX Base Station or WiMAX Tower
Typically, a base station can cover up to 10 km
radius. It is similar in concept of a cell-phone tower.
A single MAX tower can provide coverage to very
large areas big as 3,000 square miles (~8,000 square
km).[4] It can also connect to another WiMAX tower
using a line-of-sight, microwave link. This
connection to a second tower (often referred to as a
backhaul), along with the ability of a single tower to
cover up to 3,000 square miles, is what allows
WiMAX to provide coverage to remote rural
areas.[1]
B. WiMAX receiver
The receiver and antenna could be a small box or
PCMCIA card, or they could be built into a laptop the
ay WiFi access is today. WiMAX could also Boost
Government
Security.
In
an
emergency,
communication is crucial, for government officials as
they try to determine the cause of the problem, find
out who may be injured and coordinate rescue efforts
or cleanup operations. A gas-line explosion or
terrorist attack could sever the cables that connect
leaders and officials with their vital information
networks. Several base stations can be connected
with one another by backhaul microwave links.

Wire line backhauling

Microwave Point-to-Point connection
Fig 7 WiMAX Operation
8. MULTIPLE ANTENNA TECHNIQUE IN
SYSTEM DESIGN
WiMAX defines a number of optional advanced
features for improving the performance. Significant
gains in overall system capacity and spectral
efficiency can be achieved by deploying the optional
advanced antenna systems (AAS) defined in
WiMAX.
Among the more important of these advanced
features is support for multiple-antenna techniques,
hybrid –ARQ, and enhanced frequency reuse.
When the path is in a deep fade, any communication
scheme will likely suffer from errors. A natural
solution to improve the performance is to ensure that
the information symbols pass through multiple signal
ISSN: 0975 – 6779| NOV 11 TO OCT 12 | VOLUME – 02, ISSUE - 01
Page 253
JOURNAL OF INFORMATION, KNOWLEDGE AND RESEARCH IN
ELECTRONICS AND COMMUNICATION ENGINEERING
paths each of which fades independently, making
sure that reliable communications is possible as long
as one of the paths is strong. This technique is called
Diversity and it can dramatically improve the
performance over fading channels. This kind of
diversity can be obtained with the use of multiple
antennas at the transmitter as well as the receiver
side. Multiple antenna techniques can broadly be
divided into three categories
A. Diversity Schemes
There may be diversity systems with more than one
antenna at the BS and at the SS. However, in this
paper we will concentrate on simple diversity
systems that are defined as having two antennas per
channel at the BS and one at the SS. The reason for
this is that whilst the BS can carry the additional cost
of a second Transmit/Receive chain per channel, cost
constraints at the SS may preclude the use of a
second Tx/Rx chain there.
B. Smart Antenna Systems
SAS (also called Adaptive Antenna Systems-AAS)
utilize sophisticated signal processing techniques in
order to construct a model of the channel. The
knowledge of the channel is then used in order to
direct the signals towards the desired user and away
from sources of interference. This is achieved by
using techniques such as beam forming towards
desired users and null steering towards the
interferers.
C. Multiple Input Multiple Output (MIMO) Systems
MIMO systems are defined as being systems where
both the BS and the SS have a minimum of two
Tx/Rx chains, per channel, with associated antennas.
The 802.16e- 2005 WiMAX profiles have defined
two MIMO systems known as Matrix A MIMO and
Matrix B MIMO. Matrix A MIMO is a rate 1 SpaceTime Coding scheme whereas Matrix B MIMO is a
rate 2 Spatial Multiplexing Analysis of MIMO based
WiMAX Simulation For Next Generation Wireless
Communication scheme.[2]
9. FEATURES OF ADVACE MULTIPLE
ANTENNA SYSTEM
A. Diversity Gain
Achieved by utilizing multiple paths between the
transmitter and the receiver. Spatial diversity is the
simplest form of Downlink (DL) diversity gain
achieved by utilizing a minimum of two antennas per
channel at the BS.
B. Array Gain
Results from combining two signals coherently. In
the DL direction beam forming gain may result in
array gain. In the uplink direction Maximum Ratio
Combining (MRC) may also provide array gain.
C. Power Combination
In the case where M antennas are deployed in the
downlink, and each antenna is driven by a power
amplifier of equivalent rating to the single antenna
case, a power combination gain of 10log10 (M) is
achieved.
D. Interference Reduction
A feature of the SAS achieved by null steering
towards co-channel interferers.
E. Spatial Multiplexing
Two or more data streams can be resolved by one
user or to two or more users, enhancing system
capacity and spectral efficiency. For example, spatial
multiplexing in the UL direction is implemented
using Collaborative Spatial Multiplexing (CSM). It is
possible to use the SAS and MIMO techniques
together to achieve even bigger Advantage.
10. SIMULATION RESULTS
Simulation Results obtain by the simulink model.
Results of the simulation shows that as SNR
Increases BER decreases which justifies that error
rate performance of the WiMAX system increases
using MIMO hence Data rate also increases with
different modulation schemes Simulation Results are
carried out using Simulink Model . Following
simulation results are obtained by setting following
parameters.

Bandwidth=5MHz

SNR= Between 6.4 to 25dB

Delay Spread= ¼- Longest Delay Spread

NFFT=256

N used : 200

N(oversampling Factor) : 144/125

Channel used : Rayleigh Fading Channel
and AWGN Channel

No. of Transmitting Antenna: 2

No. of Receiving Antenna : 2

Sampling frequency : 5760000

Subcarrier spacing : 22500

Useful symbol time Tb : 4.4444e-005

CP Time : 1.1111e-005

OFDM Symbol time : Ts : 5.5556e-005

Sampling time = 1.7361e-007
Fig 8 Simulation Result of MIMO
As Error Rate performance Increases No. of
bits/Symbol Transmitted is increased hence System
capacity Increases A key performance measure of a
wireless communication system is the BER. The
BER curves were used to compare the performance
of different modulation and coding scheme used. The
effects of the different antenna pattern, CP, different
ISSN: 0975 – 6779| NOV 11 TO OCT 12 | VOLUME – 02, ISSUE - 01
Page 254
JOURNAL OF INFORMATION, KNOWLEDGE AND RESEARCH IN
ELECTRONICS AND COMMUNICATION ENGINEERING
channel condition were also evaluated in the form of
BER. Hence, considering Scatter Plots, BER plots
provided us with a comprehensive evaluation of the
performance of MIMO based WiMAX simulation for
next generation wireless communication for different
states of the wireless channel.
11. CONCLUSION
The implementation advances multiple antennas for
wireless communication systems like WiMAX has
gain huge interest. Wireless communication is based
on radio signals. Most high-rate applications such as
file transfer or video streaming were wire line
applications. In recent years, however, there has been
a shift to wireless multimedia applications, which is
reflected in the convergence of digital wireless
networks and the Internet. For that WiMAX is an
evolving wireless networking standard for point to
multipoint wireless networking which works for the
“last mile” connections. The major goal and the
purpose of this paper is to analyze the performance of
the WiMAX network with advance antenna
technique MIMO. Also the WiMAX system with
MIMO involves the various steps like link budget
calculations, impact of interference as well as
antenna
diversity
techniques.
With
the
implementation of OFDM with multiple antenna
technique, the performance of the WiMAX system
can be improved by minimizing the inter-symbol
interference effect. and also with the MIMO, Error
Rate performance Increases No. of bits/Symbol
Transmitted is Increased hence System capacity
Increases.
12.REFERENCES
[1] WiMAX white paper, ”Multiple antenna system
in WiMAX”, WiMAX forum certified.
[2]
Theodore
S.Rappaport,
”Wireless
Communication Principles and Practice”. Second
Edition, Printice Hall of India Private Limited, 2006.
[3Amitabh kumar.’Mobile Broadcasting with
WiMAX: Pricipals, Technology and Applications’,
Focal Press USA, 2008.
[4] Proakis, J.G Digital Communications 4th Ed. New
York; McGraw Hill, 2000.
[5] White Paper “Understanding WiMAX and 3G for
Portable/Mobile Broadband” Intel, December -2008.
[6]www.wimaxforum.org/home
[7]en.wikipedia.org/wiki/wimax/
[8] William C. Y. Lee, “Wireless & Cellular
Telecommunications”, McGraw-Hill Date: 2005
[9]Rick S. Blum, Jack H. Winters, and Nelson R.
Sollenberger, “The
Capacity of Cellular Systems with MIMO”, IEEE
Communications
Letters Vol. 6, No. 6, June 2002.
[10] Muhammad Nadeem Khan, Sabir Ghauri, “The
WiMAX 802.16e
Physical Layer Model”, IEEE Transaction.
[11] Hongfeng Wang, “Overview of WiMAX
Technology”.
ISSN: 0975 – 6779| NOV 11 TO OCT 12 | VOLUME – 02, ISSUE - 01
Page 255