Channel Shortening Equalizers for UWB Rake Receivers: Design and Performance Analysis

UWB systems occupy large bandwidths with very low power spectral densities. This feature makes UWB channels highly rich in multipaths. To exploit the temporal diversity, a UWB receiver usually incorporates Rake reception. Each multipath in the channel carries just a fraction of the signal energy. This phenomenon dictates a Rake receiver with a large number of fingers to achieve a good performance. Eventually, the Rake structure becomes very complex from analysis and design perspectives and expensive too. This book proposes channel shortening or time domain equalization as a technique to reduce the complexity of the UWB Rake receiver. It begins with the definition of channel shortening and provides a summary of the existing channel shortening equalizer (CSE) designs and their limitations. Consequently, this book presents several CSE designs to reduce the UWB Rake receiver complexity. A detalied performance analysis of the proposed designs indicates that the CSEs can play a significant role in designing a simple and cost effective Rake receiver for UWB systems. This book should be useful to the research students exploring new CSE designs and applications.