Prof.Dr. : Hamdy Al Mikati Comm. & Electronics Dep year 4th Smart antennae Prof.Dr. : Hamdy Al Mikati Comm. & Electronics Dep year 4th

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

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 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 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 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

With Without Multiple SDMA Access System GSM/GPRS CDMA Example 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

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

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