一种适用于高阶QAM信号的改进自恢复均衡算法

An amending self-recovering equalization algorithm for high-order QAM system

本文通过对传统的常模算法进行改进和推广,提出了一种新的常模算法。该算法结合了常模算法优势,利用判决符号的指数幂构成的加权项调整代价函数的模值。在均衡器系数迭代的过程中,可以通过选择权系数,调整MSE的估计值,达到提高算法的稳态性能的目的。理论分析和仿真结果表明,对于高阶的QAM信号来说,在相同的条件下,与常规常模算法相比,提出的算法具有更快的收敛速度和更低的稳态残差;当载波频偏较大时,与多模算法相比,提出的算法仅仅均衡信号的能量,不影响其相位,因此,更适合后端的载波同步处理,得到更好的系统性能。

In this paper, a novel blind qualization algorithm is proposed by generating the conventional constant moduls algorithm. The proposed algorithm, which combines the benefits of the Constant modul algorithm, uses exponential weighted symbols of the decision output to adjust the modulus in the cost function. During the equalizer tab update process, the MSE can be adjusted so that superior performance of the proposed algorithm in steady-state can be obtained by selecting a the weight factor. Analysis and simulation results demonstrate that compared with conventional blind qualization algorithms, the proposed algorithm provides superior performace by increasing the convergence rate and decreasing the steady-state mean square error, which is more efficient for blind demodulation for high-order QAM signal. When there exist big frequency-offset, the proposed algorithm is more efficiency for carriery recovery because it equalizates only the energy of signal and do not affect the phase of signal.