18-06-2011, 03:22 PM
Presented by: Rashmikanta Dash
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Introduction
Rapid growth of wireless communication
Multi-services requirement
Effective usage of frequency band
Classic antennas are omni-directional
smart antenna
What is Smart Antenna ?
Concept of SDMA system
Arrange in a particular geometric form
Use few methods to change EM wave pattern
Switched beam system
Adaptive antenna system
Switched beam system
Adaptive antenna system
Why Smart Antenna
Higher capacity (traffic/area)
Better transmission quality and/or coverage
Why Smart Antenna
Reduction of transmitter power
Reduction of delay spread
Accurate user position estimation
Limiting effects of the wireless channel
Multi-path propagation gives rise to
fading
inter-symbol interference
time variation of signals
Co-channel interference gives rise to
increased noise level and hence greater errors
Multi-path propagation
Multipath components suffer different delays
This gives rise to ISI
reject or stimulate multipath components by changing their radiation patterns
significantly reduce the requirements of equalization and/or increase CINR
Co-channel interference
Interference from other directions than wanted user
suppress unwanted user by placing nulls in directions of unwanted signals
improved transmission quality and/or system capacity
How Smart Antenna works
Uniform Linear Array geometry
Uniform Circular Array geometry
Uniform Linear Array geometry
Uniform Circular Array geometry
Conclusion
Smart Antenna offer new ways to combat and/or exploit the spatial channel
Smart Antennas reduce co-channel interference, improve BER performance and hence capacity