基于随机共振的微弱OFDM子载波数估计改进算法

An Improved Algorithm for Estimating the Number of Weak OFDM Subcarriers Based on Stochastic Resonance

针对OFDM信号中实际子载波数的估计问题,以提高检测峰值、降低信噪比门限、增大估计精度为目的,在倒谱法及其小波改进法的基础上,引入随机共振实现微弱信号的增强,使子载波个数估计性能得到提升。仿真结果表明,基于随机共振的改进算法稳健性强,可以较大程度地提高系统输出的局部信噪比,最高可达14dB,有效降低了估计误差,在较差的高斯白噪声信道下仍然可以准确估计该参数,信噪比门限可降低约5dB,为OFDM信号的信息恢复等后续工作打下良好的基础。

Aiming at the parameter estimation of the actual subcarriers’number in OFDM signals,an improved algorithm is proposed which can improve the peak of detection,reduce the threshold of signal noise ratio and increase the precision of estimation by introducing stochastic resonance theory into the traditional method of cepstrum and wavelet transform.The simulation results show that the improved algorithm based on stochastic resonance has strong robustness,and can greatly improve the local signal-to-noise ratio of the output through the system with reaching up to maximum of 14 dB.It can also effectively reduce the estimation error under extremely difficult condition of white Gaussian noise channel with threshold lowering about 5 dB.This new method can lay a good foundation for the follow-up work of the received OFDM signals,such as information recovery and so on.