基于混沌系统的正交小波变换盲均衡算法

针对常数模盲均衡算法(CMA)收敛速度慢、稳态误差大和局部收敛的缺点,将正交小波变换与混沌通信理论相结合,提出了一种基于混沌通信系统的正交小波变换盲均衡算法(CS-WT-CMA)。该算法充分利用了混沌映射的伪随机性、遍历性、相关性以及无限宽带功率谱等特点,将混沌调制系统用于产生宽带混沌信号,使用混沌信号作为载波,在调制的同时直接对发射信号进行扩频,从而降低了信道输入信号的自相关性,更好地抑制了码间干扰和多径衰落;同时对均衡器输入信号进行正交小波变换,并作能量归一化处理,降低了信号的自相关性,从而有效地加快了收敛速度。水声信道仿真结果表明,与正交小波变换盲均衡算法(WT-CMA)相比,该算法收敛速度更快、稳态误差更小。

Orthogonal Wavelet Transform Blind Equalization Algorithm Based on the Optimization of Chaos Systems

Due to the disadvantages of low convergence rate,big steady-state and local convergence error of traditional constant modulus blind equalization algorithm(CMA),by applying the orthogonal wavelet transform and the chaotic communication theory,an orthogonal wavelet transform blind equalization algorithm based on the chaotic communication systems(CS-WT-CMA)is proposed.A chaotic modulation system is used to produce broadband chaotic signal as the carrier signals and spread spectrum of the transmit signals.Accordingly,it reduces the autocorrelation of the input signals of the channel,the ISI(Inter-Symbol Interference)and the multi-path fading.Meanwhile,the proposed algorithm uses the de-correlation ability of the wavelet transform to accelerate the convergence rate.Simulations in underwater acoustic channels indicate that the proposed algorithm outperforms WT-CMA in terms of both the convergence rate and the mean square error.