Performance analysis and comparison of adaptive beam forming algorithms for Smart Antenna Systems

Smart Antenna Systems (SAS) are deployed in wireless communication system to improve the spectrum efficiency, eliminate the multi-access interference, co-channel interference (CCI) and the multi-path fading [1]. This intelligence enables the antenna systems to improve the range, quality and coverage of the system and leads to maximize the system capacity. This is achieved by beam forming algorithms and auto tracking of the desired signals. This uses the transmitted signals from a fixed set of antenna elements in an array which are weighted and combined to form a steering beam that tracks a mobile unit (MU) as it moves. This allows the SAS to dynamically focus radio frequency resources on a particular MU with minimal noise, interference and allied degrading effects. A systematic comparison and performance analysis of algorithms like Recursive Least Squares (RLS), Least Mean Squares (LMS) and Constant Modulus Algorithm (CMA) has been done in this paper. The analysis parameters used for comparison of above algorithms are response towards beam forming, interference rejection, convergence and bit error rate (BER).