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Smart AntennaSmart AntennaRashmikanta DashRashmikanta DashRegd.no:0601209202Regd.no:0601209202ETC-A-52ETC-A-52
OUTLINEOUTLINEIntroductionWhat is Smart Antenna ?Why Smart Antenna ?How Smart Antenna works ?
◦ULA◦UCA
Conclusion
IntroductionIntroductionRapid growth of wireless
communicationMulti-services requirementEffective usage of frequency bandClassic antennas are omni-directional
smart antenna
What is Smart Antenna ?What is Smart Antenna ?
Concept of SDMA systemArrange in a particular geometric formUse few methods to change EM wave pattern
◦ Switched beam system◦ Adaptive antenna system
Switched beam systemSwitched beam system
。 select one of several beams to enhance received signals
Adaptive antenna Adaptive antenna systemsystem
。 adaptive beam system can adjust its antenna pattern to enhance the desired signal
。 null or reduce interference
。 collect correlated multipath power
Why Smart AntennaWhy Smart Antenna
Higher capacity (traffic/area)Better transmission quality and/or
coverage
Standard Coverage
Extended Coverage
Why Smart AntennaWhy Smart Antenna
Reduction of transmitter powerReduction of delay spreadAccurate user position estimation
Fixed cell shape Dynamic cell shape
Limiting effects of the wireless channelMulti-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 propagationMultipath components
suffer different delaysThis 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
MPMobile 1
Interference
How Smart Antenna worksHow Smart Antenna works
Uniform Linear Array geometryUniform Circular Array geometry
UUniformniform L Linearinear A Arrayrray geometrygeometry
cos ( 1) cos( ) ( ) 1 .....Tjkd j L kd
ULAa g e e
( 1) 0T
lr l d
1
( ) ( ) ( )M
m mm
t s t
x aBase-band signal
UUniformniform C Circularircular A Arrayrray geometrygeometry
2 ( 1) 2 ( 1)cos sin
T
l
l lR
L L
r
(0, ) (1, ) ( 1, )( ) ( ) .....Tj j j L
UCAa g e e e
2 ( 1) 2 ( 1)( , ) cos cos sin sin
l ll kR
L L
1( ) ( )....... ( )T
Mt s t s ts
( ) ( ) ( ) ( )t t t X A s n
1( ) ( .... ( ) ( )M L x M A a a
1
( ) ( ) ( )M
m mm
t t
x a s
ConclusionConclusionSmart Antenna offer new ways to
combat and/or exploit the spatial channel
Smart Antennas reduce co-channel interference, improve BER performance and hence capacity
THANK YOU……………..THANK YOU……………..