Optimization Capabilities of LMS and SMI Algorithm for Smart Antenna Systems (RESEARCH NOTE)

Abstract

In the present paper convergence characteristics of Sample matrix Inversion (SMI) and Least Mean Square (LMS) adaptive beam-forming algorithms (ABFA) are compared for a Smart Antenna System (SAS) in a multipath environment. SAS are employed at base stations for radiating narrow beams at the desired mobile users. The ABFA are incorporated in the digital signal processors for adjusting the weights to adjust the beam on the desired user and generate null in the direction of interferer. SMI and LMS algorithms are used with SAS for improving the performance of wireless communication system by optimizing the radiation pattern according to the signal environment. This can enhance the coverage and capacity of the system in multipath environment by reducing the interference and noise. The data rate can be enhanced by mitigating fading due to cancellation of multipath components. In this paper optimization capabilities of SMI and LMS are considered by changing of parameters. The results reveal improvement in gain, speed of convergence and reduction in side-lobe level.