水声信道盲均衡的符号判决双模新算法

Blind Equalization of Underwater Acoustic Channel Using a Kind of Sign Decision Double Modulus Algorithm

针对常数模算法(CMA)收敛后均方误差大、双层符号误差常数模算法(DSECMA)收敛速度慢的缺陷,利用CMA的稳健性好和DSECMA计算量小的优点,提出了一种符号判决双模新算法(SDDMA)。该算法将均衡器与判决器输出序列模的平方差同均衡器输出序列模平方与DSECMA的常数模之差进行比较,根据比较结果,使迭代过程在CMA和DSECMA之间自动切换。该算法收敛后计算量比CMA小、均方误差比CMA与DSECMA都小,收敛速度比CMA与DSECMA快,有利于信息的实时恢复。水声信道盲均衡的仿真实验结果,进一步验证了该算法的性能。

Aiming at large Mean Error Square （MSE） of Constant Modulus Algorithm （CMA） and low convergence rate of Double Sign Error CMA （DSECMA）, a Sign Decision Double Modulus Algorithm（SDDMA） based on the stability of the CMA and the low computational complexity of DSECMA, was proposed. The iteration process of the proposed algorithm can alternate automatically between CMA and DSECMA via comparing the sign of square error between the modulus of equalizer output sequence and that of arbiter output sequence. It has lower computational complexity than CMA, smaller MSE than the CMA and the DSECMA, and higher convergent speed than the CMA and the DSECMA. Therefore, it is very suitable for the real recovery of the underwater data transmission. The performance of the SDDMA is proven via computer simulation for the equalization of the underwater acoustic channel.