A novel frequency coded orthogonal cognitive UWB pulse and modulation

In this paper, a novel frequency coded orthogonal IR-UWB (Impulse Radio UWB) pulse design method based on orthogonal carriers and ternary PN (Pseudo Noise) code is presented. The basic idea of the new approach is that the frequency-shifted sub-pulses are used to generate the orthogonal pulses by coding with PN sequence in frequency domain. Because the orthogonal carriers and PN codes are introduced into IR-UWB, the new method not only has the advantages of both the traditional IR-UWB and Multi-banded OFDM UWB, but also improves the efficiency of the instantaneous spectrum and energy of the transmitting UWB signal. Furthermore, the Auto-correlation and Cross-correlation characteristic of the proposed pulses are better than those of other conventional pulses. In addition, by the aid of Cognitive Radio technology, it can be guaranteed the transmitting signal in accordance with FCC spectral mask and coexistence, interference avoidance with other traditional narrow band system. And simulation results show the unique characters of the proposed pulse.