近程高速水声毫米波通信仿真与试验验证*

水声信道的严重双扩特性极大地限制了水声高速通信的稳健性。针对近程高速水声通信技术的需求,该文基于水声毫米波频段,提出了一种基于超奈奎斯特发射技术及高阶调制技术的单载波的水声毫米波通信技术。而超奈奎斯特发射技术以及高阶调制给接收机带来了极大的挑战:一是超奈奎斯特发射技术引入了严重的符号间干扰,二是高阶调制系统的符号检测对信道估计的精度要求很高。针对以上问题,该文提出了一种基于迭代信道估计技术的迭代软反馈DFE接收机技术。仿真实验表明:采用128QAM高阶调制时,在较为严重的多途衰落信道条件下,采用所提出的接收机可以在15 dB时实现无误码传输。信道水池试验证明:当通信带宽为300 kHz,通信符号率为300k符号/秒且采用64QAM调制时,在发射平台慢速运动的条件下可以实现900 kbps的净数据率,其相应的频谱利用率高达6 Bits/s/Hz。

Simulation analysis and experimental verification for near range underwater acoustic millimeter communication

The performance of high-speed underwater acoustic (UWA) communications is greatly limited by the severe doubly-spread characteristics of the underwater acoustic channel. For the demand of short-range high-speed underwater acoustic communication technology, in this paper, a UWA millimeter wave (mmWave) communication receiver is proposed for single carrier (SC) UWA communication. The proposed SC UWA mmWave communication is based on the super-Nyquist transmission technology and high-order modulation technology. The super-Nyquist transmission technology and high-order modulation bring great challenges to the receiver as follows: 1) Super-Nyquist transmission technology introduces severe inter-symbol interference (ISI), 2) Symbol detection of high-order modulation systems requires high accuracy of channel estimation. In order to address the above problems, iterative channel estimation is proposed for soft feedback based DFE. Simulation results show that the proposed receiver can achieve an error-free transmission at 15dB under the condition of more serious multi-path fading channel when 128QAM high-order modulation is adopted. The pool test also demonstrates that the net data rate of 900kbps can be achieved under the condition of slow motion of the transmitting platform when the communication bandwidth is 300kHz, the communication symbol rate is 300k symbols/second for 64QAM modulation, and the corresponding spectrum utilization rate is up to 6 Bits/second/Hz.