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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。
Aiming at the shortcomings of constant modulus blind equalization algorithm (CMA), such as slow convergence rate, large steady-state error and local convergence, this paper proposes an orthogonal wavelet transform blind equalization based on chaos communication system by combining orthogonal wavelet transform with chaos communication theory Algorithm (CS-WT-CMA). The algorithm makes full use of the characteristics of chaotic map such as pseudorandomness, ergodicity, relativity and infinite wideband power spectrum. The chaotic modulation system is used to generate wideband chaotic signal. The chaotic signal is used as a carrier. The modulation signal is directly transmitted to the transmitting signal Spread spectrum, so as to reduce the autocorrelation of the channel input signal, and better suppress the intersymbol interference and multipath fading; at the same time the equalizer input signal orthogonal wavelet transform, and energy normalized, reducing Signal self-correlation, thus effectively speeding up the convergence rate. The simulation results of underwater acoustic channel show that compared with the WT-CMA algorithm, the proposed algorithm has faster convergence rate and less steady-state error.