摘要
在水声通信中,发射机与接收机之间的相对运动产生的多普勒效应,由于其时变性常常导致补偿时的采样内插发生错误,造成自适应均衡器的发散,使整个系统的性能严重下降。提出了一种时变多普勒补偿算法,算法采用一种内嵌二阶锁相环的判决反馈均衡器来估计跟踪时变多普勒变化并及时更新内插采样率,而不需要单独的估计环节。并基于上述方法设计了一种时变内插滤波器来完成多普勒的补偿。基于湖试数据的仿真结果表明该系统在通信距离达到15km,相对速度从0到6m/s变化,加速度为1m/s2时能很好的工作,并且数据率能达到4kb it/s,特别适合于水声相位相干通信的实时处理。
In underwater acoustic communication, interpolation rate of compensation is adversely affected by time-varying Doppler, which is caused by the move between the transmitter and the receiver and will result in divergence, presenting serious effect on system performance. A new time - varying Doppler estimation and compensation scheme is presented, which can update interpolation rate timely . The estimation of the Doppler shift is performed using a second order phase - locked loop in conjunction with the decision feedback equalizer （DFE） and a separate estimation step is not required. The compensation of time - varying Doppler can be done by a kind of time - varying interpolater designed in this paper. Simulation results show that the method can efficiently compensate for the Doppler effects on phase coherent modulation systems. The system has a good performance and the data rate is 4kbit/s with the communication distance up to 15km in the case of relative velocities up to 6m/s and acceleration up to lm s2.
出处
《计算机仿真》
CSCD
2008年第11期328-330,338,共4页
Computer Simulation
基金
国家自然科学基金(60572098)
关键词
水声通信
多普勒频移
二阶锁相环
判决反馈均衡
Underwater acoustic communication
Doppler
Second order phase - locked loop
Decision feedback equalizer （DFE）
