Transcript Smart antennae - 123seminarsonly.com

Prof.Dr. : Hamdy Al Mikati
Comm. & Electronics Dep
4th year
Crew
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Ahmed Aaref
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Ahmed Ismael
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Ahmed Mohammed Abdel Moteleb

Ali Sabry Ali Mustafa
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Islam
Outlines
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Antennae systems
What is smart antennae ?
Advantages & drawbacks of smart
antennae.
Different types of smart antennae and
its benefits
Application of smart antennae in
Mobile technology
ANTENNA
SYSTEMS
Sectorized
System
Basic
Sectorized
System
HigherOrder
Sectorized
System
Diversity
System
Switched
Combining
System
Gain
Combining
System
Scanning
System
Beamforming
System
MIMO
System
Fixed
Beamformer
System
Adaptive
Beamformer
System
What is a Smart Antenna ?
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A smart antenna system
combines multiple antenna
elements with a signalprocessing capability to
optimize its radiation and/or
reception pattern automatically
in response to the signal
environment.
In reality antennas are not
smart; it is the digital signal
processing, along with the
antennas, which makes the
system smart .
Advantages Of Smart Antennae
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Better coverage and range
Increased system capacity
Spatial diversity
Multipath management
Reduce co channel interference(CCI)
Improve building penetration
Power efficiency
Reduced expense
Smart Antenna Drawbacks
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Their transceivers are much more complex
than traditional transceivers.
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Needs separate transceiver chains for each
array antenna element & accurate real-time
calibration for each of them.
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System costs in the short term.
Smart Antenna Systems
Switched Beam System
• Finite fixed patterns( nulls & SLL)
• Low Side lobes are directed to
Interferers
Adaptive Array System
• Infinite (scenario-based) patterns
with steered nulls
• SLL Reduction

40 dB
Smart Antenna Systems Comparison
CRITERIA
SWITCHED BEAM
ADAPTIVE ARRAYS
INTEGERATION
• Easy to implement
• Low cost
• Transceiver complexity
• High cost
• Less hardware
redundancy
RANGE/COVERAG
• More coverage
compared
to conventional systems
• Less coverage
compared to adaptive
array
More coverage compared
to switched beam system
INTERFERENCE
REJECTION
•Difficulty in distinguishing
between desired signal
and interferer
• Does not react to the
movement of interferers.
• Focusing is narrower
• Capable of nulling
interfering signals
Switched (Fixed) Beam System
i.
It is the simplest smart antenna technique using fixed BF
systems & it’s an extension of cell sectoring
ii.
It forms multiple fixed beams with heightened sensitivity in
particular directions and switches from one beam to another
as the cellular phone moves throughout the sector
iii. It is an alternative to Higher-Order Sectorized System by
dividing the macro-sector into several micro-sectors without
Antennas increasing in the BS site.
iv. The same beam can be used for UL or DL
Block Diagram
It Consists of :
 phase shifting network : forms multiple beams looking in
certain directions (i.e. Buttler Matrix or Blass Matrix)
 RF Switch : actuates the right beam in the desired direction
 The control logic is governed by an algorithm which scans all
the beams and selects the one receiving the strongest signal
based on a measurement made by the detector
Benefits & Limitations
Benefits:
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Coverage Extension (from 20% to 200 % Compared to
Conventional BS)
Compatible with the Systems
Low Complexity & Cost
Limitations:
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Susceptibility to interfering signals or multipaths arriving
from angles near that of the desired signal
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Scalloping
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Lack of path diversity (No Coherent Combining)
Adaptive Beam System
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It is fully smart antenna System
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It likes a Switched Beam System but with a Signal
Processing Controller
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The Signal processor steers the main beam towards the
desired MS, follows it as it moves & the nulls toward the
interfering signals
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The Processing is governed by Complex Computationally
intensive Algorithms
Block Diagram
 In this Digital Beamformer, the Adaptive System utilizes base
band Adaptive & DOA Algorithms to Continuously distinguish
between desired signals, multipath, and interfering signals (
There are many adaptive algorithms ( Blind or Non Blind) to
update the array Weights, each with its speed of Convergence
and required Processing time (i.e CMA & LMS adaptive
algorithms)
There are many DOA-estimation methods that can calculate the
DOA of all incoming signals (i.e. MUSIC Algorithm)
SDMA (Space Division Multiple access)
SDMA system block diagram
SDMA concept
SDMA is the most sophisticated utilization of smart antenna
technology
 It is based upon the concept that a signal arriving from a
distant source reaches different antennas in an array at different
times due to their spatial distribution
Example
Multiple
Access
Without
SDMA
With
SDMA
GSM/GPRS
Transmission OR
Reception of every user
in a time & frequency
band to the base station,
Limited capacity of the
system
Multiple simultaneous
transmissions in the same
frequency
band, multiplying the
capacity of the system
CDMA
Capacity is limited by its
SIR
boosting the SIR in the
system, Capacity
Improvement
System
Usage Of Smart Antenna Technology
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Cell Phones
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WiFi Applications for access points and clients
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WiMax/4G Mobile Applications for tower, base stations and
clients
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Laptops, Palmtops (Mobile personal digital assistant (PDAs))
and Handset Applications
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3G Cellular (UMTS)
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RFID
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Ultra Wide Band/Bluetooth
QUESTIONS......?
THANKS