矢量多载波多元差分混沌移位键控在水声信道下的性能研究

水声信道具有严重的时频双选择衰落特性，使得设计性能稳健的水声通信系统极为困难。为了克服水声信道时频双选择衰落带来的信道难以跟踪的挑战，提出一种采用非相干检测的多载波混沌通信系统，该系统基于差分混沌移位键控，将参考信号以及经扩频调制的信息承载信号当作矢量组，对这些矢量组进行离散傅里叶逆变换(inverse discrete Flourier transform， IDFT)完成多载波调制，经串-并转换后输出。在时频双选择性衰落信道下的仿真表明该系统具有良好的抗多普勒频移的特性，此外，在仿真水声信道和实测水声信道下的实验结果表明，该系统在水声信道下能够获得稳健的性能，相对于已有的多载波多元差分混沌调制方案，具有更好的抗时频双选择衰落的性能。

Vector multicarrier M-ary differential chaos shift keying forunderwater acoustic communication

Underwater acoustic channel has severe time frequency selective fading characteristic. It makes to design robust underwater acoustic communication system with difficulty. To meet this challenge, a vector multicarrier M-ary differential chaos shift keying (V-MM-DCSK) is proposed, in which the reference signal and M-ary information bearing signals are transformed onto multi-carriers by vector inverse discrete flourier transform (IDFT) and serial parallel converter. Numerical results over time frequency doubly fading channel show that the proposed system has good capacity of resistance to Doppler shift. In addition, numerical results of simulated underwater acoustic channel and sea trial show that the proposed system can achieve robust performance. The proposed system has better BER performance compared to the multicarrier M-ary DCSK (MM-DCSK) system over time-frequency selective fading channel and underwater acoustic channels.