宽零陷广义高斯滤波器组多载波通信在水声双扩展信道中的应用

Extended Gaussian Function Based Filterbank Multicarrier Communications in Doubly Dispersive Underwater Acoustic Channels

针对正交频分复用通信在水声多普勒信道中存在严重的子载波间干扰问题,设计了基于广义高斯函数的滤波器组多载波复用系统。该滤波器组在保证子载波时频于二维平面上具有准正交性的前提下,通过扩宽目标时-频点的零陷,提高了系统对时延-多普勒双扩展的鲁棒性。同时,将分数间隔FFT频域均衡算法扩展到了该系统中,以纠正机动性平台的多普勒频偏。仿真分别设计了多径不一致多普勒扩展信道及时变信道两种场景,所设计系统的误比特率性能均比传统OFDM有明显提高。

An extended Gaussian function based filterbank multicarrier(FBMC) system is designed since conventional Orthogonal Frequency Division Multiplexing(OFDM) suffers from severe inter-carrier interference(ICI) in presence of Doppler shift or carrier synchronization errors. The proposed system preserves quasi-orthogonality between subcarriers in time-frequency domain with widened nulls to enhance the system robustness to channel dispersion. In the meantime, the fractional FFT based frequency domain equalization is extended to the FBMC system to compensate for the motion-induced Doppler shift. Simula tion results demonstrate that the bit error rate(BER) performance of the proposed system outperforms that of the conventional OFDM system under both pathspecific Doppler spread and time-varying channel.