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).