SMART ANTENNA

HUMAN HEARING SYSTEM – AN ANALOGY FOR SMART ANTENNA

DEFINITION 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. Beam the radio signal directly at a user to follow the user as they move.

SDMA Space Division Multiple Access implies that more than one user can be allocated to the same physical communications channel simultaneously in the same cell, provided they are separated by an angle. In systems providing full SDMA, there will be much more intracell handovers and therefore more monitoring by the network is necessary.

WHY SMART ANTENNA..? MULTI-PATH PROPAGATION Fading Different delays Inter Symbol Interference To reject or stimulate multipath components by changing the radiation patterns

CO-CHANNEL INTERFERENCE Interference from other directions than wanted user Increased noise level To suppress unwanted user by placing nulls in directions of unwanted signals To improve transmission quality and system capacity

TYPES OF SMART ANTENNA Switched lobe or switched beam: Simplest technique Basic switching function between separate directive antennas or predefined beams of an array The setting that gives the best performance, usually in terms of received power, is chosen

Generalization of the switched lobe concept Dynamically phased array: Generalization of the switched lobe concept Includes a direction of arrival (DoA) algorithm for the signal received from the user Continuous tracking can be achieved

Adaptive array: DoA to determine the direction towards interferers is added Radiation pattern can then be adjusted to null out the interferers Maximize the signal to interference ratio by special algorithms & space diversity techniques (receive multipath signals & combine)

How can an antenna be made more intelligent..? Modifying the physical design by adding more elements Antenna system can shift the signals before transmission at each of the successive elements for a composite effect Controlling signal phases A DSP weighting scheme This basic hardware and software concept is known as the ‘phased array antenna’

MIMO (MULTIPLE INPUT MULTIPLE OUTPUT) It’s the use of multiple antennas at both the transmitter and receiver to improve communication performance.

ADVANTAGES Increased signal gain Better range/coverage Fewer base stations are needed which in turn reduces infrastructure cost Interference rejection & load balancing Increased capacity Spatial diversity Multipath resolution Higher data rates

Conventional Smart Antenna Legacy RF System Patented Smart Antenna Power Distribution Legacy RF System Power Distribution Patented Smart Antenna Software Low Capacity High Capacity Signal Interference from other users High Complexity 128W Signal Interference from other users Low Complexity 2 W Power Level Power Amplifier Module Power Level Power Amplifier

APPLICATIONS Applications Description RADAR SONAR Communications Phased array RADAR; air traffic control; synthetic aperture RADAR SONAR Source location and classification Communications Smart antenna systems; Directional transmission and reception; sector broadcast in satellite communications Imaging Ultrasonic; optical; tomographic Geophysical Exploration Earth crust mapping; oil exploration Astrophysical Exploration High resolution imaging of universe Biomedical Neuronal spike discrimination; fetal heart monitoring; tissue hyperthermia; hearing aids