一种鲁棒性强的OFDM 水声通信系统*

为了在不同衰落水声信道下实现正交频分复用水声通信，该文提出了一种鲁棒性强的正交频分复用水声通信方案，方案包括编码调制、信道估计和多普勒估计等内容。为了使该系统更稳健，整个信道编码分为两个步骤。首先，循环冗余校验编码器和里德-所罗门编码器用于编码整个数据包，然后循环冗余校验编码器和Turbo 编码器用于编码每个数据帧，其中比特交织编码调制技术用来对抗信道的时变特性。为了得到水声信道估计，使用线性最小均方误差估计器来处理导频数据得到信道估计值。多普勒估计包括帧的多普勒估计和符号的多普勒估计。实验结果表明该系统在不同的衰落信道下都能实现正确的跟踪和译码，系统的鲁棒性能优越。此外，该系统算法计算简单，易于实现，具有良好的工程应用价值。

A robust OFDM underwater acoustic communication system scheme

In order to realize the orthogonal frequency division multiplexing underwater acoustic communication under the different fading underwater acoustic channels, a robust underwater acoustic communication scheme of coding and modulation, channel estimation, Doppler scale estimation using the orthogonal frequency division multiplex signals has been put forward. In order to get more robust system, the whole channel coding is divided into two steps. First of all, the cyclic redundancy check (CRC) encoder and the Reed-Solomon encoder are used to encode the whole packet, then the CRC encoder and the Turbo encoder is used to encode each frame of data. Among them, bit-interleaved coded modulation is used to combat the time-varying characteristics of the channel. To obtain channel estimation, the linear minimum mean-square error estimator is used to process the pilot data to get the channel estimate. Doppler scale estimation includes Doppler scale estimation of frames and Doppler scale estimation of symbols. The experimental results show that the system can achieve correct tracking and decoding under different fading channels, and the robust performance of the system is superior. In addition, the system algorithm is simple to calculate, easy to implement, and has good engineering application value.