Signal Processing for Cognitive Radios

PREFACE

Arguably, it is signal processing that makes a cognitive radio cognitive. Its predecessor, software-defined radio (SDR) technology, already provides a software-reconfigurable device platform by implementing most baseband radio operations in software instead of in hardware. Cognitive radios are meant to be SDRs that are cognitive and intelligent. Acquisition of knowledge through learning is a common aspect of both cognition and intelligence, while self-awareness and reasoning (application of acquired knowledge) are perhaps distinctive features of cognition and intelligence, respectively. A cognitive radio, thus, is supposed to possess all these features: self-awareness, learning, and reasoning. Clearly, these are attributes that a radio can possess mostly through signal processing. It is the signal processing algorithms, implemented on an SDR platform, that will endow a radio with self-awareness, learning, and reasoning abilities.

There are many books devoted to cognitive radios. However, none are devoted to signal processing in cognitive radios. This book is an attempt to highlight the fundamental role of signal processing in cognitive radios. One may identify two types of signal processing within a cognitive radio: signal processing for gaining spectrum awareness and signal processing for achieving efficient communications. Many processing algorithms that fall under the latter are already present in all wireless communications systems and devices. However, signal processing ...