Transmit Power Allocation among PSWF-based Pulse Wavelets in Cognitive UWB Radio

Abstract

Ultra wideband (UWB) technology has been considered as one of the suitable transmission techniques for implementing a cognitive radio system, where spectrum-agile UWB waveforms achieve adaptation features. One approach for designing such waveforms relies on orthogonally combining PSWF-based pulse wavelets. In a cognitive UWB radio environment with N users, with respect to the case of one sub-band accessed by one user, whose transmitting signal is M-ary pulse shape modulated, we get different eigenvalues by transmitting these pulses in a multipath fading channel, we propose water filling scheme, depending on the different eigenvalues, to optimize the power allocation among them. Simulation results show that the scheme improves the sub-band channel data throughput compared with the scheme that power is equal allocated among these pulse wavelets, when the SNR is low, which is the normal case in UWB communications