Abstract: Due to the great increase in the number of users in mobile communication various problems arise such as improper sectorization, frequency reusability, handling complexity etc. So the use of Smart Antennas is indispensible. Smart Antennas includes the concept of adaptive signal processing to efficiently get the desired radiation pattern to accommodate more number of users in the limited frequency spectrum. Least Mean Square (LMS) and Normalised Least Mean Square (NLMS) Algorithms are the adaptive beamforming algorithms used in Smart Antenna systems. This paper compares the performance of these algorithms on the basis of radiation pattern and the number of iterations performed to minimize the mean square error to reach the optimum values of antenna weight vector which are the essential factors for any adaptive beam forming algorithm. The results depict NLMS as a better adaptive beamforming algorithm.
Keywords: Smart Antenna, Adaptive beam forming, LMS algorithm, NLMS algorithm.