Receiver Architectures for Software-defined Radios in Mobile Terminals: the Path to Cognitive Radios

The increasing need for functional flexibility in radio systems to accommodate the proliferation of wireless standards will make implementation of wireless standards on reconfigurable radio platforms the only viable option in the coming years. We address the choice of the reconfigurable analog receiver architecture for mobile, battery-powered terminals and analyze in detail two extreme cases: a state-of-the-art fully integrated zero-IF receiver and an RF bandpass sampling architecture. Finally, we discuss how SDR receivers pave the way towards more sophisticated cognitive radios that sense the wireless environment and adapt their communication parameters.