A Combined Doppler Scale Estimation Scheme for Underwater Acoustic OFDM System
A Combined Doppler Scale Estimation Scheme for Underwater Acoustic OFDM System
复制标题
水声正交频分复用系统的组合多普勒尺度估计方案
DOI：
10.1142/s0218396x15400044
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发表时间：
2015-12-01
影响因子：
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通讯作者：
Liu, Songzuo
中科院分区：
文献类型：
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作者：
Ma, Lu;Qiao, Gang;Liu, Songzuo
针对水声信道中正交频分复用（OFDM）系统的性能受到频变多普勒频移的严重限制，提出了一种组合多普勒尺度估计方法，该方法包括两个步骤：（1）在数据传输前发送两个相同的短OFDM符号，并在符号前加上循环前缀（CP）作为前导码，进行初始多普勒尺度估计;（2）采用基于CP的方法对每个CP-OFDM块进行精细的同步和多普勒尺度估计，并最终采用重采样方法对非均匀多普勒频移进行补偿。所提出的方案已被测试与真实的数据从松花湖实验中的发射机是以约2.5 m/s的速度移动，和黄海试验中的发射机和接收机是自由浮动的波浪和电流。通过逐块处理获得了优异的性能结果，而无需缓冲整个分组，这适合于时变UWA信道上的实时接收处理。
Since the performance of orthogonal frequency division multiplexing (OFDM) system is severely limited by frequency-dependent Doppler shifts over underwater acoustic (UWA) channels, a combined Doppler scale estimation scheme is proposed, containing two steps: (1) the initial Doppler scale estimation via transmitting two identical short OFDM symbols preceded by a cyclic prefix (CP) as a preamble prior to the data transmission; and (2) fine synchronization and Doppler scale estimation for each CP-OFDM block are achieved by the CP-based method, and eventually the resampling methodology is adopted for nonuniform Doppler shifts compensation. The proposed scheme has been tested with real data from the Songhua Lake experiment where the transmitter is moving at a speed of about 2.5 m/s, and the Yellow sea trial in which the transmitter and receiver are floating freely with waves and currents. Excellent performance results are obtained by block by-block processing, without buffering the whole packet, which is suitable for real-time receiver processing over time-varying UWA channels.