Software Defined Radio: Enabling Technologies

7

Baseband Processing for SDR

David Lund^a and Bahram Honary^b

Many technologies require substantial research and development to facilitate the emergence of mature and generic software defined radio architectures, as will be evident from a perusal of the contents of this volume or the other literature in the field. Our own chapter focuses upon the broad ranging topic of baseband processing, an important and central element of such architectures. Alongside networking of these enhanced capability and flexible systems, the radio frequency processing aspects of the physical layer are required to accommodate a flexible range of different frequencies, formats, and environments. Baseband processing is perhaps one of the most potentially fruitful areas of development anticipated over the next few years – indeed, significant progress is already evident.

7.1 The Role of Baseband Architectures

The baseband of any radio system is responsible for digitally transforming raw data streams into the correct format ready for transmission over a known wireless channel. In a transmitter this simply consists of formatting of the data and introduction of any redundancy required to improve reception. At the receiver, the information from the radio frequency front end has to be carefully analyzed in order to extract correctly the data which was intended for reception. This requires synchronization, demodulation, channel equalization, channel decoding, and multiple access channel extraction. These, and many ...