The Best Variable Step-size LMS Algorithm for Smart Antennas in a SDMA Mobile Communication Environment with Changing Noise and fading

The purpose of this paper is to study the performance of variable step-size LMS algorithms for smart antennas with an application in SDMA wireless communication systems where changing noise and fading are troublesome. We will find the best variable step-size algorithm for dealing with these conditions and change it in a way to slightly improve its performance. Proposed algorithm gives better results for beam forming in desired direction and provides deeper nulls in the direction of interference signals. Simulations are made to illustrate the beam forming for various conditions including different array space factors, changing noise and fading.

Keywords:

smart antennas , adaptive algorithms , variable step-size least mean square , beam forming , fading