Acoustic Science and Technology Laboratory, Harbin Engineering University, Harbin, 150001, China.
Qingdao Innovation and Development Base, Harbin Engineering University, Qingdao, 266000, China.
J Acoust Soc Am. 2023 Feb;153(2):1027. doi: 10.1121/10.0017116.
Conventional double differential phase-shift keying modulation amplifies the phase noise and performs poorly under the time-varying direct-sequence spread-spectrum (DSSS) communication system. Therefore, the authors propose an iterative reception for DSSS communication in time-varying underwater acoustic channels. First, bit-interleaved coded modulation with iterative decoding integrated with multi-symbol differential detection is used. Second, this paper uses cross correlation method to estimate and track the Doppler shift of each symbol. Based on Doppler estimates, a dynamic linear prediction model is proposed to estimate and track the channel phase variation. Third, an algorithm for adaptive selection of reference signals is utilized to recover the magnitude attenuation of correlation peaks. Numerical simulation results demonstrate that the proposed reception achieves around 9 dB gain compared to conventional differential decision reception under constant acceleration of 0.14 m/s. During the acoustic communication experiment in Songhua Lake, the proposed reception was tested by using a moving source at a speed of 1-6 knots at 2-m depth and the farthest distance between the transceivers is 2.8 km. The proposed reception achieves only one frame error from a total of 205 frames collected in the lake experiment, and it also achieves error-free communications over 96 frames during a 10 km depth deep-sea experiment.
传统的双差分相移键控调制会放大相位噪声，在时变直序扩频（DSSS）通信系统中性能不佳。因此，作者提出了一种用于时变水下声信道中 DSSS 通信的迭代接收方案。首先，采用具有迭代解码的比特交织编码调制与多符号差分检测相结合。其次，本文使用互相关方法来估计和跟踪每个符号的多普勒频移。基于多普勒估计，提出了一种动态线性预测模型来估计和跟踪信道相位变化。第三，利用自适应参考信号选择算法来恢复相关峰的幅度衰减。数值仿真结果表明，与传统的差分判决接收相比，在 0.14 m/s 的恒定加速度下，所提出的接收方案可获得约 9 dB 的增益。在松花江的水声通信实验中，利用速度为 1-6 节、深度为 2 m 的移动声源，在收发器之间的最大距离为 2.8 km 的条件下，对所提出的接收方案进行了测试。在湖上实验中，总共采集了 205 个帧，其中只有一个帧出现错误，在 10 km 深海实验中，实现了 96 个以上无差错通信。
