Smart Antenna Rashmikanta Dash Regd.no:0601209202 ETC-A-52

OUTLINE Introduction What is Smart Antenna ? Why Smart Antenna ? How Smart Antenna works ? ULA UCA Conclusion

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 。select one of several beams to enhance received signals

Adaptive antenna system 。adaptive beam system can adjust its antenna pattern to enhance the desired signal 。null or reduce interference 。collect correlated multipath power

Why Smart Antenna Higher capacity (traffic/area) Better transmission quality and/or coverage Higher capacity (traffic/area) Spectrum is expensive therefore of great interest to operators Better transmission quality and/or coverage Energy better focussed on user (greater C/I) or greater coverage Co-channel interference suppression Dynamic cell coverage

Why Smart Antenna Reduction of transmitter power Reduction of delay spread Accurate user position estimation Reduction of transmitter power Reduction of delay spread Tuning of the channel for desired delay profile characteristics Accurate user position estimation Requirement for new standards Fixed cell shape Dynamic cell shape

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 Mobile Smart Antenna LoS MP

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 Mobile 2 Smart Antenna LoS MP Mobile 1 Interference

How Smart Antenna works Uniform Linear Array geometry Uniform Circular Array geometry

Uniform Linear Array geometry

Base-band signal

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

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