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

Mitigation of Fading

Different delays

Inter Symbol Interference

To reject or stimulate multipath

components by changing the

radiation patterns, So Lower BER

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Enhance Communication System Performance, including - Capacity -Range

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 phases

A 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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ADVANTAGES

Increased signal gain

Better range/coverage

Fewer base stations are needed which in turn reduces infrastructure cost

Interference rejection & load balancing

Increased capacity

Spatial diversity

Multipath resolution

Higher data rates

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Legacy

RF System

Power Distribution

Power Amplifier Module Power Level

128W

Signal Interference from other users

Low Capacity

High Complexity

Conventional

Patented

Smart Antenna

Software

Power

Distribution

Power Amplifier Power Level

2 W

High Capacity

Signal Interference from other users

Low Complexity

Smart

Antenna

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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 communications

Imaging

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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