Ultra Wideband FM: A Straightforward Frequency Domain Approach

This paper presents a novel approach based upon wide-band FM techniques to generate a constant-envelope UWB signal whose bandwidth can be independently chosen from the data rate. Data is modulated on a sub-carrier using e.g., FSK techniques. The various users distinguish themselves by their subcarrier frequency. Simultaneous demodulation of multiple FM signals having the same RF center frequency is possible when a linear FM demodulator, not preceded by any limiting devices, is used. Since the RF signal is not pulsed, no carrier synchronization (as in impulse radio) is required. Spectral roll-off of the UWBFM signal is steep allowing this system to co-exist with WLANs operating at e.g., 5.7 GHz.