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Prof.Dr. : Hamdy Al Mikati Comm. & Electronics Dep year 4 th. Smart antennae. Crew . Ahmed Aaref Ahmed Ismael Ahmed Mohammed Abdel Moteleb Ali Sabry Ali Mustafa Islam. Outlines. Antennae systems What is smart antennae ? Advantages & drawbacks of smart antennae.
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Prof.Dr. : Hamdy Al Mikati Comm. & Electronics Dep year4th Smart antennae
Crew • Ahmed Aaref • Ahmed Ismael • Ahmed Mohammed Abdel Moteleb • Ali Sabry Ali Mustafa • Islam
Outlines • 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
?What is a Smart Antenna • A smart antenna system combines multiple antenna elements with a signal-processing 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 • 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 • Their transceivers are much more complex than traditional transceivers. • Needs separate transceiver chains for each array antenna element & accurate real-time calibration for each of them. • System costs in the short term.
Infinite (scenario-based) patterns • with steered nulls • SLL Reduction 40 dB • Finite fixed patterns( nulls & SLL) • Low Side lobes are directed to • Interferers
Switched (Fixed) Beam System It is the simplest smart antenna technique using fixed BF systems & it’s an extension of cell sectoring 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 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. 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: • Coverage Extension (from 20% to 200 % Compared to Conventional BS) • Compatible with the Systems • Low Complexity & Cost • Limitations: • Susceptibility to interfering signals or multipaths arriving from angles near that of the desired signal • Scalloping • Lack of path diversity (No Coherent Combining)
Adaptive Beam System • It is fully smart antenna System • It likes a Switched Beam System but with a Signal Processing Controller • The Signal processor steers the main beam towards the • desired MS, follows it as it moves & the nulls toward the interfering signals • 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 SDMAconcept • 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
Usage Of Smart Antenna Technology • Cell Phones • WiFi Applications for access points and clients • WiMax/4G Mobile Applications for tower, base stations and clients • Laptops, Palmtops (Mobile personal digital assistant (PDAs)) and Handset Applications • 3G Cellular (UMTS) • RFID • Ultra Wide Band/Bluetooth