The problem of information transmission through water pipelines is addressed and a class of methods based on differentially encoded orthogonal frequency division multiplexing (OFDM) is proposed. Specifically, two methods are investigated; one based on conventional differential encoding with an estimation of the average time of arrival and another based on double encoding. Results show that the first approach improves performance in the low signal to noise ratio (SNR) region, while the second is better suited at high SNR. Adopting these techniques closes the performance gap between differential OFDM systems and coherent OFDM systems while retaining the benefits of computational simplicity.

中文翻译：

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水管道信道中的差分正交频分复用通信。

解决了通过输水管道传输信息的问题，提出了一种基于差分编码正交频分复用（OFDM）的方法。具体来说，研究了两种方法。一个基于常规差分编码，估计平均到达时间，另一个基于双重编码。结果表明，第一种方法可改善低信噪比（SNR）区域的性能，而第二种方法更适合于高SNR。采用这些技术弥合了差分OFDM系统和相干OFDM系统之间的性能差距，同时保留了计算简便性的优点。