S.Ranjitha

Smart Antenna

What is Smart Antenna?

A smart antenna consists of an antenna array, that changes the array pattern in response to Signal environment to improve the performance of a communication system

Types of Smart Antenna systemsSmart antenna system

Switched beam systems

Single beam directional antenna

Multi beam directional antennas

Adaptive array systems

Single user beam forming

Multi user beam forming

Switched beam array

Multiple fixed beams with one beam turned on towards the desired signal or a single beam that is steered towards the desired signal.

Coverage pattern

Antenna Array

Active Beam

Block diagram of Switched Beam Antenna

Single beam directional antenna

Only one beam is active

Only transceiver exists

Multiple beam directional antenna:

Example of SDMA system

Many directional antennas are used

No. of beams = No. of transceivers

Switched Beam Antennas

Adaptive Array Antennas • Direction of algorithm(DOA)

• Tracking

• Minimizing interfering signals

• High SIR

Adaptive Array Coverage

Block diagram of adaptive array system

Single user tracking:

• Beam is adjusted to track a user

• Single transceiver is enough since one user is active

Multi user tracking:

Different beam patterns

Simultaneous transmissions

SDMA achieved

Multi transceiver beam pair

Adaptive Array Antennas

Space division multiple access

Comparing switched beam and adaptive array

Switched beam array

Adaptive array

The goals of a smart antenna system

• The features of a smart antenna system are

- signal gain.

- inference rejection.

-power efficiency.

SMART ANTENNA VS OTHER ANTENNAS

They can null out interference from other nodes.

Contains an array of antennas elements and decide

on which elements to receive signals (or transmit on)

from and how much power to use on each element.

. Advantages of smart antenna

Range extensionBuilding penetration and Hole fillingDelay spread Co-channel interference Multiple access interference Multipath managementSystem capacityPower control

• cellular and wireless networks

• radar

• electronic warfare (EWF) as a counter measure to electronic jamming

• satellite systems

APPLICATION

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