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SMART ANTENNA

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HUMAN HEARING SYSTEM – AN ANALOGY FOR SMART ANTENNA

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DEFINITION

A smart antenna system combines multiple antenna

elements with a signal processing capability to

optimize its radiation and/or reception pattern

automatically in response to the signal environment.

Beam the radio signal directly at a user to follow the

user as they move.

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SDMA

Space Division Multiple Access implies that more than

one user can be allocated to the same physical

communications channel simultaneously in the same

cell, provided they are separated by an angle.

In systems providing full SDMA, there will be much

more intracell handovers and therefore more

monitoring by the network is necessary.

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WHY SMART ANTENNA..?MULTI-PATH

PROPAGATION

Fading Different delays Inter Symbol Interference

To reject or stimulate multipath components by changing the radiation patterns

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CO-CHANNEL INTERFERENCE

Interference from other directions than wanted user

Increased noise level

To suppress unwanted user by placing nulls in directions of unwanted signals

To improve transmission quality and system capacity

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TYPES OF SMART ANTENNA

Switched lobe or switched beam:

Simplest technique Basic switching function between

separate directive antennas or predefined beams of an array

The setting that gives the best performance, usually in terms of received power, is chosen

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Dynamically phased array:

Generalization of the switched lobe concept Includes a direction of arrival (DoA) algorithm for the

signal received from the user Continuous tracking can be achieved

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Adaptive array:

DoA to determine the direction towards interferers is added

Radiation pattern can then be adjusted to null out the interferers

Maximize the signal to interference ratio by special algorithms & space diversity techniques (receive multipath signals & combine)

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How can an antenna be made more intelligent..?

I. Modifying the physical design by adding more elements

II. Antenna system can shift the signals before transmission at each of the successive elements for a composite effect

Controlling signal phasesA DSP weighting scheme

This basic hardware and software concept is known as the ‘phased array antenna’

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MIMO(MULTIPLE INPUT MULTIPLE OUTPUT)It’s the use of multiple antennas at both the

transmitter and receiver to improve communication performance.

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ADVANTAGESIncreased signal gain

Better range/coverage

Fewer base stations are needed which in turn reduces infrastructure cost

Interference rejection & load balancing

Increased capacitySpatial diversity

Multipath resolution

Higher data rates

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Legacy RF System

Power Distribution

Power Amplifier ModulePower Level

128W

Signal Interference from other users

Low Capacity

High Complexity

Conventional

PatentedSmart Antenna

Software

Power Distribution

Power AmplifierPower Level

2 W

High Capacity

Signal Interference from other users

Low Complexity

SmartAntenna

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APPLICATIONS

Applications Description

RADAR Phased array RADAR; air traffic control; synthetic aperture RADAR

SONAR Source location and classification

Communications Smart antenna systems; Directional transmission and reception; sector broadcast in satellite

communicationsImaging Ultrasonic; optical; tomographic

Geophysical Exploration

Earth crust mapping; oil exploration

Astrophysical Exploration

High resolution imaging of universe

Biomedical Neuronal spike discrimination; fetal heart monitoring; tissue hyperthermia; hearing aids

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