一种双模式变步长恒模算法

Varying step-size dual-mode constant modulus algorithm

针对非常模信号,著名的恒模算法表现出较大的稳态误差和较慢的收敛速度.为克服上述缺点,提出了一种双模式变步长恒模算法.新算法通过对输出信号的判决来判断当前均衡器工作是否存在误操作.当均衡器工作正常时算法使用变步长方法,当均衡器工作存在误操作时算法使用零步长方法,从而充分发挥出步长对恒模算法的有利影响.仿真实验结果证明新算法具有比恒模算法更快的收敛速度和更小的稳态误差.

When applied to non-constant modulus signals, the famous constant modulus algorithm（CMA） shows large steady-state mean square error（MSE） and slow convergence rate. In order to overcome those defects,this paper proposes a new dual-mode constant modulus algorithm based on varying step-size, which,through the decision of the equalizer output signal,can detect the misoperation in the equalizer. If the equalizer works well the algorithm uses a varying step-size method, otherwise a zero step-size method, making full use of the advantages of CMA while avoiding its defects. The computer simulation shows that the new algorithm is faster in convergence rate and lower in steady-state MSE than the CMA.