l0-范数约束的稀疏多径信道分数间隔双模式盲均衡算法

摘要

A blind equalization approach called l0-norm constraint fractionally spaced sparse adaptive dual-mode algorithm is proposed for multiple phase shift keying (MPSK) signal in deep fading sparse multipath channels.Based on the traditional fractionally spaced dual-mode blind equalization algorithm,and motivated by the sparse adaptive filter theory,a fractionally spaced dual-mode least mean square error cost function with the l0-norm penalty on the equalizer tap coefficients is constructed.Then,the update formula of the tap coefficients is derived according to the gradient descent method.Moreover,the iteration step is updated adaptively by drawing upon the normalized proportionate factor.Theoretical analysis and simulation results show that compared with the sparse blind equalization algorithm based on the threshold,the blind equalization algorithm based on the fractional order norm and the fractionally spaced dual-mode blind equalization algorithm,the proposed algorithm has advantages in increasing the convergence rate and decreasing the residual inter-symbol interference.The presented blind equalization algorithm provides a fast and effective method for receivers to recover transmitted signals in underwater acoustic communication systems.%针对深衰落稀疏多径信道下多进制相移键控(Multiple Phase Shift Keying,MPSK)信号的盲均衡问题,提出了一种l0-范数约束的分数间隔稀疏自适应双模式盲均衡算法.该算法借鉴传统的分数间隔双模式盲均衡算法思想,结合稀疏自适应滤波理论,首先利用l0-范数对均衡器抽头系数进行稀疏性约束,构造出一种l0-范数约束的分数间隔双模式最小均方误差代价函数,然后依据梯度下降法推导出盲均衡器抽头系数更新公式,并对迭代步长进行归一化和比例系数化.理论分析和仿真实验表明,与基于门限稀疏化的盲均衡算法、基于分数阶范数的盲均衡算法及分数间隔双模式盲均衡算法相比,本文所提算法在保证较快收敛速度的前提下,能有效降低剩余符号间干扰.本文设计的盲均衡算法为水声通信系统中接收方恢复出发送信号,提供了一种快速有效的方法.