Low-cost Smart Antennas

2Beamforming Algorithms for Smart Antennas

2.1 Introduction

The smart antenna technique, in most cases, is an application of the traditional digital beamforming technique in array signal processing to the area of wireless communications [1–9]. In this chapter we focus on some basic principles of beamforming, particularly digital beamforming, and introduce some representative beamforming methods and algorithms. First, we give a brief introduction to beamforming and then introduce some basic concepts in beamforming, such as steering vectors, spatial aliasing, beam response, and beam pattern. We then present two fixed beamfomer design methods, finite impulse response (FIR) filter based design and least squares based design, followed by two traditional adaptive beamforming algorithms: the reference signal based beamformer and the Capon beamformer. Next, we consider two specific applications with their associated blind adaptive beamforming algorithms: one for satellite navigation systems and one for wireless communications. Finally, we provide a review of the particular area of low‐cost adaptive beamforming with two different approaches: hybrid beamforming, which employs analogue and digital beamformers at different stages, and robust adaptive beamforming, which focuses on two representative robust algorithms.

The aim of beamforming is to effectively estimate the signal of interest in the presence of noise and interferences employing an array of antennas, which are located at different ...