SMART ANTENNA –AOA ESTIMATION EMPLOYING MUSIC ALGORITHM And DIGITAL BEAMFORMING By VARIABLE STEP-SIZE LMS ALGORITHM With NOVEL MAC PROTOCOL For IEEE 802.11

Smart antenna using multiple antennas exploring the SDMA technology has been used in wireless communication systems which provides higher spectrum efficiency, improved link quality and throughput through frequency reuse, reduction of intersymbol interference (ISI) and co-channel interference rejection (CCI)[1]. Space Division Multiple Access, where multiple user signals are simultaneously transmitted and received over same conventional time and frequency channels by using multiple antennas, dramatically increases spectral efficiency. SDMA is realized with beam forming and null forming techniques which accounts for co-channel interference rejection. Channel equalization is done using adaptive equalizer to mitigate the effects of ISI. This paper discusses SDMA technology with digital beam forming with the novel idea of including the Variable step-size LMS algorithm along with MUSIC algorithm employed in MAC protocol for IEEE 802.11 and the results of simulation are analyzed for their performance. Key-words :smart antenna, adaptive beamforming, intersymbol interference, variable step-size lms algorithm, adaptive equalizer, Angle of Arrival estimation(AOA), MAC protocol, MUSIC algorithm