Underwater acoustic OFDM channel equalization based on virtual time reversal mirror
Underwater acoustic OFDM channel equalization based on virtual time reversal mirror
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作者：
Yin Yan-lin
针对水声多径信道在正交频分复用（OFDM）通信中造成的严重码间干扰问题，提出了一种虚拟时反转信道均衡方案。VTRM具有时域压缩和频域相位共轭的特性，可以缩短信道脉冲响应，减轻声信道引起的相位畸变。采用匹配追踪（MP）算法估计信道脉冲响应，可以准确估计信道的幅度、时延和相位。它为VTRM通道均衡提供了通道信息。相对于传统匹配相关信道估计方法无法估计信道相位和估计精度较低的缺点，该方法有了很大的改进。仿真、池径和松花湖实验表明，在OFDM水声通信中，VTRM信道均衡的性能优于PTRM和LS信道均衡。
To solve the problem of the severe inter-symbol interference of orthogonal frequency division multiplexing(OFDM) communication caused by underwater acoustic multipath channel, a virtual time reversal channel equalization scheme was proposed. VTRM was able to shorten the channel impulse response and alleviate the phase distortion caused by the acoustic channel for its characteristic of the temporal compression and phase conjugation in frequency domain. The matching pursuit(MP) algorithm was applied to estimate the channel impulse response which could estimate the channel amplitude, time delay and phase accurately. It provided the channel information for the VTRM channel equalization. It also improved a lot compared to the traditional matching correlation channel estimation method which couldn't estimate the channel phase and the estimation precision was low. The simulation, pool trail and Songhua lake experiment show that the performance of VTRM channel equalization is better than that of the PTRM and LS channel equalization in the OFDM underwater acoustic communication.