一种变步长梯度寻优的RSC码识别算法

Blind Recognition of RSC Code Generated Polynomial Based on Variable Step Size of Gradient Search

针对RSC码的编码器生成多项式的盲识别问题,在分析信号模型的基础上,基于EM算法的思想,在M步骤中,通过建立步长大小与当前梯度的非线性函数关系,提出了一种变步长梯度寻优算法。该算法相比于定步长算法而言,参数的估计值收敛到真实值的速度更快,且具有较强的抗噪声能力。仿真结果表明:同等条件下,所提算法在第4次迭代就收敛到了真实值,而定步长算法则需要迭代20次以上;在抗噪声性能方面,蒙特卡洛实验结果表明,所提算法在信噪比为0dB时,其参数的识别概率都能够达到80%以上。

According to blind recognition of RSC code generated polynomial,the nonlinear function between step size and gradient was established in M step based on EM algorithm.As a result,a novel algorithm of variable step size of gradient search was proposed based on analysis of the signal model.Compared with the fixed step algorithm,the new algorithm has better cognitional performance on the condition of low SNR and has a strong ability to resist noise.Besides,the convergence of parameter estimation curve is rather faster.The computer simulation results show that the proposed algorithm can converge at real value at 4 th iteration,while for fixed step size algorithm,more than 20 iterations are needed.In terms of performance of noise resistance,the Monte Carlo trial results show that the correct ratio of recognition can reach more than 80% at SNR of 0 dB.