一种面向水下移动通信的组合差分扩频水声通信方法

针对水下移动平台(AUVs)直接序列扩频(DSSS)水声通信过程中大多普勒时变带来的频偏及载波相位跳变问题，该文提出一种组合差分扩频通信方法。该方法设计一种2维组合差分(TCD)扩频帧结构，接收端通过对重复码时域加窗相关实现时变多普勒粗估计；接收端提出一种频率压缩-能量接收器(FC-ED)，通过采用能量检测接收器提高接收端处理多普勒容限，使用频率压缩法多频点压缩处理进一步提高系统鲁棒性，实现扩频码识别映射解码；最后提出一种组合差分算法，实现2维组合扩频间的极性差分解码，在能量接收映射解码基础上引入极性调制，进一步提高频谱利用率。经理论及仿真试验分析，该方法具备一定的抗时变多普勒能力，在恒加速度相对运动–8 dB信噪比条件下误码率小于10^–2。

Combination Differential Direct Sequence Spread Spectrum Algorithm for Mobile Underwater Acoustic Communication

To deal with the problem of frequency offset and carrier phase fluctuation caused by the conventional Doppler on the DSSS (Direct-Sequence Spread-Spectrum) underwater acoustic communication between AUVs (Autonomous Underwater Vehicles), a combination differential direct sequence spread spectrum algorithm is proposed. The Doppler rough estimation is realized through Two-dimension Combination Difference(TCD) spread spectrum frame structure, and the Doppler tolerance is extended through the Frequency Compression-Energy Detector(FC-ED), then an algorithm of combination differential is proposed for polarity decoding. Using the combination differential direct sequence spread spectrum algorithm, good performance (BEK<10–2) is achieved for a signal-to-noise ratio as low as –8 dB based on at-sea data.