Due to the time-varying property of the underwater acoustic (UWA) channel, the significant Doppler spread will severely degrade the performance of direct-sequence spread-spectrum (DSSS) communications. The relative velocity variation between the transmitter and the receiver will cause both the phase rotation and the magnitude loss of correlation peak, during the long transmission of the DSSS packet. To solve this problem, the authors propose a novel transceiver design for the UWA DSSS communications. At the transmitter, the triple differential phase shift keying (D PSK) modulation is adopted to overcome the phase rotation, whereas the phase noise will be amplified resulting in the signal-to-noise ratio (SNR) loss. At the receiver, the improved bit-interleaved coded modulation with iterative decoding algorithm for D PSK is used to recover the SNR loss, in which the D PSK demodulator is treated as the convolutional decoder, and the linear prediction is adopted to track the channel variation. Furthermore, an adaptive selection of local reference signal is also applied to recover the correlation loss. Theoretical simulation shows that the proposed transceiver can effectively mitigate the performance loss caused by the motion acceleration, and the performance gain is significant over the conventional.

中文翻译：

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时变水下声通信中用于三差分PSK调制的迭代接收器

由于水下声学（UWA）通道的时变 特性，明显的多普勒扩展将严重降低直接序列扩频（DSSS）通信的性能。在DSSS数据包的长时间传输过程中，发送器和接收器之间的相对速度变化将导致相位旋转和相关峰值的幅度损失。为了解决这个问题，作者为UWA DSSS通信提出了一种新颖的收发器设计。在发射机处，三重差分相移键控（D 采用PSK）调制来克服相位旋转，而相位噪声将被放大，从而导致信噪比（SNR）损失。在接收器处，采用迭代解码算法对D进行改进的比特交织编码调制 PSK用于恢复SNR损失，其中D PSK解调器被视为卷积解码器，并采用线性预测来跟踪信道变化。此外，还应用本地参考信号的自适应选择以恢复相关损失。理论仿真表明，所提出的收发器可以有效地减轻运动加速度引起的性能损失，并且性能增益比传统的显着。