Frequency-band Coded Orthogoanl UWB Pulse Design Based on Chirp Signals for Cognitive NB Suppression

In this paper, a novel frequency-band coded orthogonal UWB pulse design method based on chirp (linear frequency modulated, LFM) signal is presented. The basic idea of the new approach is that the up-chirp pulses and down-chirp pulses located at different frequency-bands are used to synthesize the orthogonal pulses by coding with pseudo noise (PN) sequence in frequency domain. Auto-correlation and cross-correlation property of the proposed chirp pulses are better than those of other conventional pulses. Furthermore, the new method also improves the efficiency of the instantaneous spectrum and energy of the transmitting UWB signal. In addition, by the aid of cognitive radio technology to adjust the chirp envelope and the frequency-sweeping range at NBI bands, it is can be guaranteed the transmitting signal in accordance with FCC spectral mask and coexistence, interference avoidance with other traditional narrow band system. And simulation result showed that the proposed pulse could reduce the effect of narrow band interference on UWB system with litter complexity.