时间反转镜分类研究及其在水声通信中的应用

Classified Study on Time Reverse Mirror in Underwater Acoustic Communication

时间反转镜可在没有任何先验知识的情况下具有自适应匹配声信道的作用。主动式时间反转镜(ATRM)要求阵元收发合置,且信号需两次经过信道,效率低下,而阵处理则进一步增加了系统的复杂性,难以满足水声通信节点追求结构简单、低功耗的要求。为克服上述弊端,提出应用单阵元被动式时间反转镜(PTRM)和虚拟式时间反转镜(VTRM),并对单阵元时间反转镜的聚焦增益进行了讨论。计算机仿真结果表明,单阵元时间反转镜可聚焦多途信号,实时实现自适应信道均衡,从而抑制码间干扰、提高信噪比。

Time reversal mirror （TRM） could match the acoustic channel automatically without any transcendental knowledge. Active time reversal mirror （ATRM） needs monostatic sensor, and the signal propagates through the acoustic channel twice leading to low efficiency. Further, the array processing enhances the complexity, which could not satisfy the modem＇s requirement of simple structure and low-power cost. In order to overcome these disadvantages, the single sensor passive time reversal mirror （PTRM） and virtual time reversal mirror （VTRM） were proposed and the focusing gain of single sensor TRM was calculated. The results of numerical simulations show that the single sensor TRM is able to focus the multipath signal and adaptively equalize the acoustic channel real time, consequently mitigate intersymbol interference （ISI） and enhance SNR.