UWB | Narrow band | |
Antennas | • Antenna should be small with gain and wide bandwidth. • Low-impedance antenna and good wide-band matching • Codesign is necessary between antenna and front end. | • Small high-Q antenna can be easily achieved with good gain. • With a 50 Ω impedance and easy to match • Antenna and front end can be designed independently. |
RF front end | • Wide-band LNA are power consuming and hard to match. • Automatic gain control (AGC) is part of the front end. • Relaxed requirements on linearity • Partial filtering can be achieved by the antenna. | • Narrow-band LNA is easy to match. • High linearity requirements for non-constant envelop modulation (such as OFDM) • Tough filtering is needed to satisfy out-of-band emission. |
Intermediate frequency | Not needed | AGC, mixer, RF oscillator, PLL |
Analog baseband | Needs very high bandwidth A/D converter digital sampling oscillator techniques | Small bandwidth A/D converter |
Digital baseband | • Coherent detection • Very fine time resolution • Precise time references | non-coherent detection |
Channel aspects | Not yet completely known but studies are ongoing | Narrow-band channel are well characterized (fading model). |