This paper presents a double-differential coded M-ary direct sequence spread spectrum (DD-MSS) underwater acoustic communication system to overcome problems of both low signal-to-noise ratio and severe Doppler effect. The system is very efficient in the challenging band-limited underwater acoustic channel and has many applications, particularly in which the transmitter and the receiver are mobile. Given that the bit error rate (BER) performance is unaffected, this scheme results in a significant improvement in the data rate compared to direct sequence spread spectrum (DSSS) communication systems. The MSS system uses M pseudo-random codes to represent k bits of information and offers advantages of a higher spectral efficiency and a lower energy consumption than the DSSS system. Both simulations and experiments are performed, and the results are discussed in the paper for the performance evaluation of the proposed scheme. The results demonstrate a better BER performance using the DD-MSS in a mobile environment.

为了克服信噪比低和多普勒效应严重的问题，本文提出了一种双差分编码M元直接序列扩频(DD-MSS)水声通信系统。该系统在具有挑战性的带限水下声信道中非常有效，并且具有许多应用，特别是在发射器和接收器是可移动的情况下。鉴于误码率 (BER) 性能不受影响，与直接序列扩频 (DSSS) 通信系统相比，该方案可显着提高数据速率。MSS系统使用M个伪随机码来表示k位信息，具有比DSSS系统更高的频谱效率和更低的能耗的优点。进行了模拟和实验，并在论文中讨论了该方案的性能评估结果。结果表明，在移动环境中使用 DD-MSS 可以获得更好的 BER 性能。