Towards Robust High Speed Underwater Acoustic Communications Using Chirp Multiplexing
Towards Robust High Speed Underwater Acoustic Communications Using Chirp Multiplexing
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DOI：
10.1109/oceans.2018.8604496
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发表时间：
2018-10
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影响因子：
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通讯作者：
Jiacheng Shi;Emrecan Demirors;T. Melodia
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文献类型：
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作者：
Jiacheng Shi;Emrecan Demirors;T. Melodia
宽带线性调频扩频 (CSS) 已在水声 (UWA) 通信中进行了研究，以保证低误码率和低传输速率。另一方面，UWA的高速传输方案，特别是正交频分复用（OFDM）技术，可以达到Mbit/s的数据速率，但以牺牲可靠性为代价。在本文中，我们提出了一种基于将信息比特复用到（准）正交线性调频信号的新传输方案，称为准正交线性调频复用（QOCM）。作为 OFDM 架构的扩展，它可以在可重新编程的硬件上轻松实现。我们通过模拟和坦克实验评估了所提出方案的性能。长距离水上传输仿真结果表明，在严重的多普勒效应下，QOCM 方案能够比 OFDM 方案实现一个数量级的性能提升。此外，我们在水箱实验中观察到，QOCM 方案能够抵抗由高达 5 节的相对速度引起的多普勒效应，这对应于中心频率为 125 kHz 时的 214:16 Hz 多普勒频移。
Wide band chirp spread spectrum (CSS) has been studied in underwater acoustic (UWA) communications to guarantee low bit error rates with low transmission rates. On the other hand, high speed transmission schemes for UWA, especially Orthogonal-Frequency-Division-Multiplexing (OFDM) technology, can reach Mbit/s data rates but at the expense of reliability. In this paper, we propose a new transmission scheme based on multiplexing information bits to (quasi-)orthogonal chirp signals, called Quasi-Orthogonal Chirp Multiplexing (QOCM). It can be easily implemented on reprogrammable hardware as an extension to OFDM architectures. We evaluated the performance of the proposed scheme with simulation and tank experiments. Results show that QOCM scheme is able to achieve one order of magnitude better performance than an OFDM scheme under severe Doppler effect posed by simulation in long distance water transmission. Moreover, we observe in water tank experiment that the QOCM scheme is resilient against to the Doppler effects induced by relative speeds up to 5 knots, which corresponds to a Doppler shift of 214:16 Hz at a center frequency of 125 kHz.