中文摘要：

针对不同的水声信道和不同的接收信噪比有着不同的最优传输速率的思想，文章根据水声信道的特殊性，提出了一种基于M元扩频的新型水声通信系统，采用不同的码本以实现不同的通信速率。文章阐述了几种码本的产生方法和性质，通过仿真，获取了在几种通信速率在加性高斯白噪声（Additive White Gaussian Noise，AWGN）和衰落信道下的误码率曲线，并得到了在10-4误码率要求下所需的信噪比，为水声通信系统的灵活性和适用性提供了一种新的解决方案。

英文摘要：

Based on the intention of optimal data rate for different channels and different received signal to noise rate （SNR）, this paper proposes a new scheme of M-ary spread spectrum telemetry to realize variable data rate by adopting different sizes of code sets over underwater acoustic （UWA） channel. This paper illuminates the variable rate scheme, the methods and characteristics of kinds of code sets. It is obtainable that the BER curves over additive white Gaussian noise （AWGN） and UWA channels as well as required SNR of 104 BER. A flexible and applicable solution is introduced for UWA communication system.