Cyclic shift keying spread spectrum OFDM method over underwater acoustic channel

2012 ◽  
Author(s):  
Lianyou Jing ◽  
Jianguo Huang
Keyword(s):  
Spread Spectrum ◽  
Cyclic Shift ◽  
Underwater Acoustic Channel ◽  
Underwater Acoustic ◽  
Acoustic Channel ◽  
Shift Keying

scholarly journals M-ary Cyclic Shift Keying Spread Spectrum Underwater Acoustic Communications Based on Virtual Time-Reversal Mirror

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3577
Author(s):  
Zhou ◽  
Liu ◽  
Nie ◽  
Yang ◽  
Zhang ◽  
...  
Keyword(s):  
Time Reversal ◽  
Spread Spectrum ◽  
Underwater Acoustic Communications ◽  
Cyclic Shift ◽  
Acoustic Communications ◽  
Underwater Acoustic ◽  
Underwater Acoustic Channels ◽  
Shift Keying ◽  
Virtual Time ◽  
Time Reversal Mirror

Underwater acoustic communications are challenging because channels are complex, and acoustic waves when propagating in the ocean are subjected to a variety of interferences, such as noise, reflections, scattering and so on. Spread spectrum technique thus has been widely used in underwater acoustic communications for its strong anti-interference ability and good confidentiality. Underwater acoustic channels are typical coherent multipath channels, in which the inter-symbol interference seriously affects the performance of underwater acoustic communications. Time-reversal mirror technique utilizes this physical characteristic of underwater acoustic channels to restrain the inter-symbol interference by reconstructing multipath signals and reduce the influence of channel fading by spatial focusing. This paper presents an M-ary cyclic shift keying spread spectrum underwater acoustic communication scheme based on the virtual time-reversal mirror. Compared to the traditional spread spectrum techniques, this method is more robust, for it uses the M-ary cyclic shift keying spread spectrum to improve the communication rate and uses the virtual time-reversal mirror to ensure a low bit error rate. The performance of this method is verified by simulations and pool experiments.

scholarly journals Deep Learning-Based Cyclic Shift Keying Spread Spectrum Underwater Acoustic Communication

2021 ◽  
Vol 9 (11) ◽  
pp. 1252
Author(s):  
Yufei Liu ◽  
Feng Zhou ◽  
Gang Qiao ◽  
Yunjiang Zhao ◽  
Guang Yang ◽  
...  
Keyword(s):  
Neural Network ◽  
Deep Learning ◽  
Spread Spectrum ◽  
Communication System ◽  
Signal To Noise Ratio ◽  
Cyclic Shift ◽  
Conventional System ◽  
Signal To Noise ◽  
Underwater Acoustic ◽  
Shift Keying

A deep learning-based cyclic shift keying spread spectrum (CSK-SS) underwater acoustic (UWA) communication system is proposed for improving the performance of the conventional system in low signal-to-noise ratio and multipath effects. The proposed deep learning-based system involves the long- and short-term memory (LSTM) architecture-based neural network model as the receiving module of the system. The neural network is fed with the communication signals passing through known channel impulse responses in the offline stage, and then directly used to demodulate the received signal in the online stage to reduce the influence of the above factors. Numerical simulation and actual data results suggest that the deep learning-based CSK-SS UWA communication system is more reliable communication than a conventional system. In particular, the collected experimental data show that after preprocessing, when the communication rate is less than 180 bps, a bit error rate of less than 10−3 can be obtained at a signal-to-noise ratio of −8 dB.

scholarly journals Multiuser Chirp Spread Spectrum Transmission in an Underwater Acoustic Channel Applied to an AUV Fleet

Sensors ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 1527
Author(s):  
Christophe Bernard ◽  
Pierre-Jean Bouvet ◽  
Antony Pottier ◽  
Philippe Forjonel
Keyword(s):  
Spread Spectrum ◽  
Multiple Access ◽  
Autonomous Underwater Vehicle ◽  
Matched Filter ◽  
Underwater Acoustic Communication ◽  
Underwater Acoustic Channel ◽  
Underwater Acoustic ◽  
Acoustic Channel ◽  
Chirp Spread Spectrum ◽  
Code Division Multiple

The objective of this paper is to provide a multiuser transmission technique for underwater acoustic communication in the framework of an Autonomous Underwater Vehicle (AUV) fleet. By using a variant of a Hyperbolically Frequency-Modulated (HFM) signal, we describe a new family of transmission techniques called MultiUser Chirp Spread Spectrum (MU-CSS), which allows a very simple matched-filter-based decoding. These techniques are expected to provide good resilience against multiuser interference while keeping good robustness to Underwater Acoustic (UWA) channel impairments like Doppler shift. Their implementation for the UWA scenario is described, and the performance results over a simulated shallow-water UWA channel are analyzed and compared against conventional Code-Division Multiple Access (CDMA) and Time-Division Multiple Access (TDMA) transmission. Finally, the feasibility and robustness of the proposed methods are verified over the underWater AcousTic channEl Replay benchMARK (Watermark), fed by several channel responses from sounding experiments performed in a lake.

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