Smart antenna for wi-max radio system

In simple words, smart antenna is such that it can sense its environment and can adjust its gain in different directions accordingly. They provide a smart solution to the problem of communication traffic overload i.e. they increase the traffic capacity. They also improve the QOS. RF spectrum is a limited resource and is becoming crowded day by day due to the advent of new technologies. The sources of interference are increasing as well and hence interference is becoming the limiting factor for wireless communication. Smart Antenna adapts its radiation pattern in such a way that it steers its main beam in the DOA (direction of arrival) of the desired user signal and places null along the interference. It refers to a system of antenna arrays with smart signal processing algorithms. Array processing involves manipulation of signals induced on various antenna elements. Its capabilities of steering nulls to reduce cochannel interferences and pointing independent beams toward various mobiles, as well as its ability to provide estimates of directions of radiating sources, make it attractive to mobile communications system designer. Array processing is expected to play an important role in fulfilling the increased demands of various mobile communications services. This paper provides a comprehensive and detailed treatment beam-forming,adaptive algorithms to adjust the required weighting on antennas, direction-ofarrival estimation methods.