浅海水声通信中的间接自适应均衡算法

Indirect Adaptive Equalization Algorithm for Shallow Water Acoustic Communication

为了消除具有时变和多径特性的浅海水声信道带来的码间干扰,该文提出了一种间接自适应均衡算法。在发送端,设计了一种适合在浅海水声信道中传输的帧结构。在接收端,利用帧头进行快速信道估计和均衡器抽头系数的初始化,通过门限的设定,有选择地激活特定位置的抽头。并采用可变步长的LMS算法进一步减小误差,更好地均衡帧体数据。理论分析和仿真结果表明,该算法具有快速收敛性和较低的硬件复杂度,对经过高阶调制的发送信号具有很好的均衡效果,可以有效地应用于浅海高速数字通信系统。

To eliminate inter-symbol interference brought from the shallow water acoustic channel which has property of time varying and multi path, an indirect adaptive equalization algorithm is proposed in this paper. A frame structure is designed, adapted to shallow water acoustic communication system in the transmitter. At receiver, frame header is used to perform fast channel estimation and initialization of equalization tap coefficients, the thresholds are set to activate taps of special position, and a variable step LMS adaptive algorithm is chosen to reduce further error when receiving frame body symbols. Theoretical analysis and simulation results show that the algorithm has fast convergence and low hardware complexity. Besides, it has good effect on the high-order modulated signal. Therefore, it will be suitable for shallow water high speed digital communication system.