Adaptive CMOS-based RF transceivers — State-of-the-art and future trends

State-of-the-art cellular transceivers are increasingly based on highly scaled CMOS technology nodes of 130 nm and beyond. In contrast to the ¿first generation¿ CMOS based transceivers, that were mainly a copy of there BiCMOS based counterparts in terms of architectures (e.g. direct-conversion receiver (DCR), direct modulation or PLL-based transmitters) and partitioning (e.g. analog I/Q interface), the ¿second generation¿ incorporated a by far more ¿digital¿ centric approach and took advantage of the technology capabilities. The ever increasing requirements towards multi-mode/multi-system capabilities favored the shift of functionality from the analog into the digital domain, due to the higher potential of digitally implemented features towards configurability. It can be anticipated that this trend towards digital centric architectures is further pushed by developments like cognitive radios (CR), dynamic spectrum access, interference management and advanced spectrum management.