A stady Redacing the Peak-to-Average Power Ratio and Ihter Carrer, In terference for MB-OFDM Based VWB Communication Sqstems

点击翻译按钮获取中文摘要

Since each subcarrier is modulated independently, an MB-OFDM signal has a large instantaneous peak power, compared with single-carrier signal. The peak power is usually measured in terms of peak-to-average power ratio (PAPR), and an MB-OFDM signal with large PAPR will be distorted by the nonlinear amplifier. Meanwhile, due, to the overlapped spectrum, MB-OFDM is very vulnerable to carrier frequency offset (CFO), which mainly arises from the frequency mismatch between the transmitter and receiver local oscillators. The CFO causes inter-carrier interference (ICI), which severely degrades the performance of MB-OFDM systems.We have proposed the PAPR reduction method, in which the PAPR reducing problem is formulated as a combinatorial optimization problem and Hopfield neural nertwork (HNN) is applied to solving the optimization. Also, by extending the MPP-based CFO estimation, we have proposed an efficient compensation scheme for the IEEE 802.11a WLAN. In this scheme, the CFO estimation is enhanced by a CFO sign detection and an autocorrelation-based estimator to avoid the ill-condition of cost function.