Joint channel estimation and power allocation for cognitive WPMCM UWB system

Abstract

Cognitive Radio aims adaptive and aware communication for better utilization of available communication resources. Cognitive ultra wideband (UWB) system obtains attractive features such as robustness to multipath fading, high data rate, low cost, and low power consumption. Wavelet packet based multicarrier modulation (WPMCM) for UWB is a tempting choice due to its inherent potential to fulfill cognitive radio requirements. In this article, we survey the effect of channel fading on cognitive radio sensing mechanism through the literature, and propose an efficient pilot pattern strategy combined with power allocation to compensate the impairment from interfering primary signal and improve the system performance. Wavelet packet based energy detection is applied for spectrum analysis of cognitive WPMCM UWB, then, optimal power allocation is derived by Lagrange multiplier method to minimize the bit error rate (BER) at the receiver. Simulation results compare BER of the system under UWB channel models and verify the performance of the proposed scheme.