Software defined radio (SDR) is an emerging form of radio architecture, which
encompasses a wide range of design techniques in order to realize a truly flexible,
and potentially future-proof, transceiver system. As a field, it is very broad, encompassing:
systems design, RF, IF, and baseband analogue hardware design, digital
hardware design, and software engineering. Covering all of these topics in sufficient
detail to become a design reference would be a huge task, therefore, this book
focuses on the former aspects of SDR, namely, systems design and RF, IF, and baseband
analogue hardware design. It also includes an introduction to some of the digital
hardware options for the baseband signal-processing element, although it does
not attempt to provide detailed design information in this area.
The emphasis on analogue hardware and digital conversion technologies stems
from the current reality that the antenna plus analogue-to-digital converter (ADC)
architecture often envisaged for future radio receivers (and similarly for the transmitter)
is far away from becoming a reality in the main cellular communications
bands. Indeed, there are some very significant challenges to overcome before this
could ever be considered a realistic architecture for cellular applications, and these
are highlighted in this book.
Many of the techniques described in the book are still at the research stage and
are presented as ideas for further development. Some of these techniques may never
become a reality and may be superseded by alternative technologies; however, their
presence in this book will hopefully stimulate such alternative ideas and further the
development of the exciting field of SDR.