A Technical Seminar report submitted in partial fulfillment of the
requirements for the award of the degree of
BACHELOR OF TECHNOLOGY
ELECTRONICS & COMMUNICATION ENGINEERING
KONDAMEEDI ANUSARIKA 18S41A0459
Department of Electronics and Communication Engineering
VAAGESWARI COLLEGE OF ENGINEERING
(Affiliated to JNTUH Hyderabad & Approved by AICTE New Delhi)
Ramakrishna Colony, Karimnagar-505527
Department of Electronics and Communication Engineering
VAAGESWARI COLLEGE OF ENGINEERING
(Affiliated to JNTUH Hyderabad & Approved by AICTE New Delhi)
Ramakrishna Colony, Karimnagar-505527
This is to certify that the mini project report entitled ‘SMART
ANTENNA’ was Submitted by the following member in Partial fulfillment of the
requirements for the award of the Degree of Bachelor of Technology in ECE, and is
bonafide record of the work performed by him/her.
KONDAMEEDI ANUSARIKA 18S41A0459
Mr. A. VENKATA REDDY Dr.Ch.SRINIVAS
Associate Professor principal
Head of the Department
The Satisfaction that accomplishes the successful completion of any task would be
incomplete without mentioning the people who make it possible and whose constant
guidance and encouragement crown all the efforts with success.
We sincerely extend our thanks to Dr.Ch.Srinivas, Principal of Vaageswari College of
Engineering , Karimnagar . We want to thank all the staff members and all our friends
for their good wishes, helping hand, and constructive criticism, which led to the
successful completion of this report.
We express my sincere thanks to Mr.A.Venkata Reddy, Associate Professor and Head
of the ECE department have given me moral support and kind attention, and valuable
guidance throughout this course.
We are immensely indebted to our parents, brother, and sisters for their love and
unshakable belief in us and the understanding and ever-decreasing grudges for not
spending time more often.
Finally, we thank all those who directly and indirectly helped us in this regard; we
apologize for not listing everyone here.
As the numbers of systems, networks and users increased over the years of
development of wireless communication systems; so has preserving a maintainable
capacity to be able to contain these increasing numbers. Since day one, wireless
communication system designers were aware of the fact that capacity and interference
were certainly going to create a problem in the very near future.This technical report
will briefly discuss a technology called Smart-Antenna, which has an adaptive nature
and is capable of solving the problems that face the conventional communication
Smart antennas are antenna arrays or group of antenna with smart processing
algorithms used to identify spatial signal signature. A smart antenna takes advantage
of diversity effect at the source (transmitter), the destination (receiver), or both.
Diversity effect involves the transmission and/or reception of multiple radio
frequency (RF) waves to increase data speed and reduce the error rate. Smart
antenna technology can overcome these capacity limits as well as improve signal
quality and let mobile telephones operate on less power. Smart antenna are also
known as adaptive array antennas, MIMO & multiple antennas.
LIST OF FIGURES
Fig.No Description Page No.
2.1 Smart antenna system-beam forming
2.2 Different type of smart antenna
2.3 SIMO – single input multiple output
2.4 MISO - multiple input single output
2.5 MIMO - multiple input multiple output
2.6 Human analogy for smart antenna
2.7 Electrical equivalent
2.8 Switched-beam system
2.9 Comparison between (a) switched scheme and (b)
2.10 Relative coverage area comparison in low and high
2.11 Block diagram of an adaptive array system
3.1 SDMA multibeam system
A Smart technology is a system or a device that has the ability to adapt to
certain changes over time while offering a broad range of possible applications.
Technologies that contain both logical and physical applications in all formats and
have the ability to automatically adapt and modify their own behaviour independently
in order to fit in with that which is presentintheir environment by sensing objects they
are dealing with and providing data for further analyzation are known to be Smart. A
Smart technology is usually a modified version of a conventional technology,the main
differences are present in the way a Smart technology gathers data and how it deals
with inputs and surroundings to save energy while offering better solutions to the
problems faced by the conventional technology. Smart technologies have great
presence in today’s world, they exist in a variety of different fields and lots of
research is being carried out in the design and implementation of such technologies.
One of the examples of Smart technologies are Smart Refrigerators, this
special type of refrigerators is programmed to better identify precisely what products
are being stored inside them and whether some products are missing or simply ran
out. Another type of a Smart technology is Smart Glasses, which is basically a
wearable computer that adds information to what its user sees, it can offer several
features as good as a Smart Phone plus a vast range of industrial and healthcare
applications. This technical report will focus on Smart Antenna, a technology that has
grown at a formidable rate especially with today’s advancements in wireless
communications that have integrated with powerful low-cost digital signal processors,
general-purpose processors and ASICs (Application-Specific Integrated Circuits).
1.1Objective of study
The main objective of my seminar is smart antenna system is to reduction of
ISI, removal of CCI, mitigation of adjacent-channel interference, enhancement of
spectrum efficiency, improvement of BER, reduction of outage probability,
improvement of transmission efficiency and reduction of hand-off rate and crosstalk.
In turn, all of these desired effects result in improved capacity, range and frequency
re-use. These objectives may be accomplished through steering nulls in the direction
of co-channel interferers and multipaths, steering a beam toward the user's direct
path or direct and multipaths, and increasing the signal-to-interference-and-noise
ratio at the array output.
Recently and over the last decade, the wireless and mobile technologies in
addition to the new and improved services have grown rapidly at exponential and
formidable rate. In the evolution of the modern telecommunication networks and
multiple access systems, the employment of the spatial processing approaches and
techniques becomes essential according to the related standards. The spatial
processing is considered as the main idea behind the use of adaptive and smart
antennas, antenna arrays, beamforming algorithms, interference cancelation,
bandwidth-efficient signaling systems, and direction of arrival (DOA) estimation
schemes (in the case of non-blind beamforming).
Smart antenna system basically consists of multiple antennas or antenna arrays
and digital signal processing algorithms that are in charge of very important functions
such as DOA estimation of the signals. In general, the wireless communication
systems development stages can be classified based on the adopted technologies
driven by the challenges of capacity demand and quality of service (QoS)
The aforementioned smart antenna systems are widely implemented in two
forms, namely, the switched beam approach where the system can choose one of
many predefined antenna beam patterns (the antenna radiation or propagation pattern
is defined as graphical representation of the power variation and radiation properties
of the antenna as a function of the direction and space coordinates), and the adaptive
array approach where the antenna adapts the radiation pattern beams in real time in
accordance with the radio environment.
The smart antennas systems achieve higher capacity increase in comparison
with the switched beam systems especially in the case of densely populated coverage
areas and reduce more effectively the negative impacts of the interference.
Additionally, there are more advantages that can be counted in favor of adaptive array
systems such as range increasing, security enhancement (more difficult to tap any
connection) , and location-based services improvements especially for emergency
situations (spatial detection characteristics).
As in the case of any system or technology, some disadvantages or drawbacks
of the smart antenna systems are found like the complexity of transmitters and
receivers design, the high computation intensity with the need of powerful digital
signal processors (DSPs), and the overall system employment cost.
At this point, two fundamental objectives should be performed by the signal
processing algorithms of the smart antenna systems, namely:
• The DOA estimation for all incoming signals;
• Adaptive real-time calculation of the weights or coefficients that are
used to steer and change the directions of the antenna array radiation
beams toward the signal-of-interest (SOI) and at the same time to place
nulls toward the signal-non-of-interest (SNOI) that is considered as
Hence, the smart antennas systems relay on the adaptive signal processing
techniques such as DOA estimation and adaptive beam forming under the use of
multiple antenna configurations (antenna arrays).
2.1 FUNCTIONS OF SMART ANTENNA:
a.Direction of Arrival Estimation (DOA):
The smart antenna system estimates the direction of arrival of the signal, using
techniques such as MUSIC (Multiple Signal Classification), estimation of signal
parameters via rotational invariance techniques (ESPRIT) algorithms, Matrix
Pencil method or one of their derivatives. They involve finding a spatial spectrum of
the antenna/sensor array, and calculating the DOA from the peaks of this spectrum.
These calculations are computationally intensive. Matrix Pencil is very efficient in
case of real time systems, and under the correlated sources.
b.Beam forming: It is the method used to create the radiation pattern of
the antenna array by adding constructively the phases of the signals in the direction of
the targets/mobiles desired, and nullifying the pattern of the targets/mobiles that
undesired/interfering targets. This can be done with a simple FIR tapped delay
line filter. The weights of the FIR filter may also be changed adaptively, and used
to provide optimal
beam forming, in the sense that it reduces the MMSE between the desired and actual
beam pattern formed. Typical algorithms are the steepest descent, and LMS
algorithms. There is an ever-increasing demand on mobile wireless operators to
provide voice and high-speed data services. At the same time, these operators want to
support more users per base station to reduce overall network costs and make the
services affordable to subscribers. As a result, wireless systems that enable higher
data rates and higher capacities are a pressing need.
FIG 2.1: SMART ANTENNA SYSTEM – BEAM FORMING
2.2 TYPES OF SMART ANTENNA
There is two type of smart antenna mainly.
Switched beam antenna systems form multiple fixed beams with heightened
sensitivity in particular directions. These antenna systems detect signal strength,
choose from one of several predetermined, fixed beams and switch from one beam
to another as the mobile moves throughout the sector. Instead of shaping the
directional antenna pattern with the metallic properties and physical design of a
single element, switched beam systems combine the outputs of multiple antennas in
such a way as to form finely directional beams with more spatial selectivity than can
be achieved with conventional, single-element approaches.
b.Adaptive Array antennas:
Adaptive antenna technology represents the most advanced smart antenna
approach as on date. Using a variety of new signal-processing algorithms, the
adaptive system takes advantage of its ability to effectively locate and track
various types of signals to dynamically minimize interference and maximize
intended signal reception. Both systems attempt to increase gain according to the
location of the user, however, only
the adaptive system provides optimal gain while simultaneously identifying, tracking
and minimizing interfering signals.
FIG 2.2: DIFFERENT TYPE OF SMART ANTENNA
Another way of categorizing smart antennas is in the number of inputs and
outputs that is used for the device. According t this classification the categories are
1.SIMO (Single Input – Multiple Output) In this method one antenna will be used
at the source and multiple antennas will be used at the destination.
FIG 2.3: SIMO – SINGLE INPUT MULTIPLE OUTPUT
2. MISO (Multiple Input – Single Output) In this method, multiple antennas will be
used at the source and only one antenna will be used at the receiver.
FIG 2.4: MISO - MULTIPLE INPUT SINGLE OUTPUT
3. MIMO (Multiple Input – Multiple Output) In this method multiple antennas will be
used at both the source and the destination. This is the most efficient method
amongst all. This method was extended recently in accordance to the IEEE
802.11n standard. This method clearly supports spatial information processing.
FIG 2.5: MIMO - MULTIPLE INPUT MULTIPLE OUTPUT
2.3 ANALOGY(HUMAN ANALOGY):
Engineering systems that have great impact in our lives are mostly derived
from man’s ability to observe nature’s complexity and integrity, especially the human
body. Hence, to give a simple view of how a Smart Antenna works we can think of
two speakers in a dark room with one listener (Check Fig 1.1 below). The listener can
determine precisely the location of the desired speaker as he moves around the room
due tovariation of the time the voice takes to arrive at each vocal sensor, in that case
the ear. Given the data present in the form of time differences,the brain -being the
human signal processor- then calculates the direction of the speaker from the time
delays of the voice received by the ears. After that, the brain simply adds the strength
of the voices from each ear in order to concentrate on the sound of the calculated
direction. Moreover, if more speakers enter the room the brain can still focus on one
conversation at a time by tuning out undesired interferes. In an opposite manner, the
listener can reply to the location of the desired speaker by the orientation of the mouth
-being the transmitter- toward the direction of the speaker.
FIGURE 2.6 HUMAN ANALOGY FOR SMART ANTENNA
2.4 ELECTRICAL EQUIVALENT:
Quite similar to the human hearing system, an electrical Smart-Antenna
system uses two antennas instead of ears, and a digital signal processor (DSP) instead
of a brain. Thus, when the DSP measures the time delays from each individual
antenna, it calculates the direction of arrival (DOA) of the desired signal, it then
modifies the phases and gains of that signal to produce a radiation pattern that focuses
on it while tuning out any undesired signals (Check Figure 1.2 below).
FIGURE 2.7: ELECTRICAL EQUIVALENT
2.5 SMART-ANTENNA SYSTEMS
2.5.1 An Overview:
Smart-Antenna systems are considered an extension for cell sectoring (a
conventional technology of increasing the capacity of a cellular structure) in which
the sector coverage is made up of multiple beams , this happens by the use of
multiple antenna arrays, and the beams’ number in each sector depends on the array
geometry. Since Smart-Antennas have the ability to concentrate their radiation pattern
towards the desired users while rejecting undesired interference, they ensure a great
coverage area for every base station. Furthermore, given that Smart-Antennas have a
high ability to reject unwanted interferences, and so a lower bit error rate (BER), they
can offer the much-needed capacity improvement, which solves the problem that
wireless communication system designers have been facing since early days. The
systems of Smart-Antennas were first introduced as Switched-Beam systems, which
after illustration of how they work a justification to the need for Smarter Antennas
will be evident .
2.5.2 Switched-Beam Systems:
In order to enhance the received signal, the Switched-Beam system can select
from one of several predefined patterns (Check Fig 2.1below) in which a user is
provided with an active beam as his portable unit moves through the cell by focusing
radiation on the DOA of the portable unit of the user. Since each sector is subdivided
into smaller sectors, therefore it is obvious that the system is an extension for cell
sectoring. As the unit moves through the cell, the system detects that movement
through certain DSP algorithms and thus activates the appropriate predefined beam
pattern, and it keeps doing that as long as the unit is moving. The aim of the
Switched-Beam system was to provide the user with the greatest signal-gain possible
according to his location. Unfortunately, given that the beams were static, users have
experienced trouble where their location was not exactly in the centre of an active
beam, which gave credit to an interferer near the centre of the active beam since the
interference had more enhancement than the desired user, a problem that was solved
by the Adaptive Array Systems .
FIGURE 2.8: SWITCHED-BEAM SYSTEM
2.5.3 ADAPTIVE ARRAY SYSTEMS
Adaptive array systems introduce more degrees of freedom because they can
“adapt” a radiation pattern to the radio-frequency (RF) signal environment in real
time. Meaning that they have the potential to direct the main beam towards the
desired unit in order to give it maximum gain while supressing all undesired
interferences. In other words, adaptive array systems can ultimately adjust the
appropriate radiation pattern for each user. This is way more superior than the
performance of a Switched-Beam System (Check Fig 2.2below).
FIG 2.9: COMPARISON BETWEEN (A) SWITCHED SCHEME AND (B) ADAPTIVE
The figure shows that the Switched-Beam system not only fails to give maximum
amplification to the desired signal, but also is unable to effectively suppress the
interferes. Adaptive array Systems also can greatly increase capacity because of their
ability to control the radiation pattern in a larger coverage area for each cell site. In
the region of of low-level interference, both types of Smart Antennas (Switched-
Beam and Adaptive array) can offer high gains over the conventional sectored
systems that use omnidirectional antennas (antennas that propagate the signal in all
directions rather than the desired direction). Nevertheless, in a region of high-level
interference, the interference suppression feature of the adaptive array systems
supplies much more coverage than either the Switched-Beam or the conventional
systems . Since the real world is a high interference environment, adaptive array
systems outperformed all other systemsin terms of capacity, interference
suppression and gain enhancement for the desired users.
FIGURE 2.10: RELATIVE COVERAGE AREA COMPARISON IN LOW AND HIGH
Adaptive array systems can track and locate signals and dynamically modify the
antenna pattern to improve reception as well as removing interference as much as
possible using appropriate digital signal-processing algorithms. The block diagram of
an adaptive array system (Check Fig 2.4below) converts the signals received into
baseband, it then locates the desired signal with the help of a DOA algorithm, after
that it keeps track of the desired signal by controlling the phases and amplitudes
(weights) of the signal. The DSP contains the DOA algorithm which in turn computes
the direction of arrival by calculating the time delays between the antennas. After that
is done, the adaptive algorithm calculates the appropriate weight that results in an
optimum radiation pattern by the help of a cost function. Since adaptive arrays are
DSP intensive, the details of how the weights and time delays are computed will not
be discussed in this report.
• Increased number of users
• Increased range
• Easily integrated
• Increased bandwidth
• Spatial Division Multiple Access (SDMA) :
SDMA is one of the ultimate goals of development of cellular radio systems, it
is among the most-sophisticated applications of smart-antenna technology; it has
very advanced spatial-processing capabilities that allow it to locate a lot of users at
the same time; and thus making different beams for each individual user (Check Fig
FIG 3.1: SDMA MULTIBEAM SYSTEM
This allows more than one user to be allocated to the exact same physical
communicationchannel in the same cell simultaneously, separated by a certain angle.
In a world that has become full of threats and vulnerabilities arising from intruders
and hackers, the need for security has greatly increased, especially with the presence
of a society that is drastically relying on transmitting personal information and
conducting business, security is of crucial importance. Smart Adaptive antennas make
it much more difficult for an intruder to tap a connection, since the intruder must be
positioned in the same direction of the user as seen from the base station to be able to
tap a connection, something which he can hardly achieve .
Many have lost their lives due to location-related issues, lots of women have been
raped and murdered in a suburb or a bar bathroom somewhere simply because they
were undetectable. With the spatial detection nature of Smart-Antenna systems,
they can be used to accurately locate humans in emergencies and save them from
dangers that would have rather been unavoidable if not for Smart Antennas .
In conclusion, Smart-Antenna development was essential for solving the problems
that faced Cell Sectorized and Switched-Beam Systems. This is where Adaptive
Array Smart-Antennas came in, a technology with an adaptive nature that
successfully solves the capacity problem along with increasing the range given their
directional quality, a quality that was missing in omnidirectional and sectorized
antennas, they have also suppressed the interferences for a most powerful, pure and
smooth communication experience.
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2. B. Pattan, Robust Modulation Methods & Smart Antennas in Wireless
Communications, Prentice Hall PTR, Upper Saddle River, NJ, 2000.
3. Special issue, IEEE Trans. Antennas Propagat., Vol.24, No. 5, Sept. 1976.
4. International Engineering Consortium, Smart Antenna Systems, an Online
Tutorial found on www.iec.org/online/tutorials/smart_ant/index.html.
5. J. C. Liberti, Jr. and T. S. Rappaport, Smart Antennas for Wireless
Communications: IS-95 and Third Generation CDMA Applications, Prentice
Hall PTR, Upper Saddle River, NJ, 1999.