基于Haar小波变换的直扩信号参数盲估计

为解决低信噪比下直扩信号的参数估计问题,提出了一种基于H aar小波变换实现直扩信号伪码(PC码)速率和符号周期盲估计的新型算法。阐述了小波变换表征和检测直扩信号相位瞬变的原理,给出了直扩信号小波变换的具体形式。通过对直扩信号小波变换频谱特征的具体推导,详细论述了通过小波变换提取这两个参数的算法原理和具体步骤。仿真实验表明,在码元数为400及扩频因子为63的参数条件下,该文所提出的伪码速率和符号周期估计算法可至少工作在-18 dB和-14 dB的低信噪比下,且其性能优于某些典型的算法。

Parameter blind estimates of DS/SS signals based on Haar wavelet transforms

An algorithm based on the Haar wavelet transform(HWT) was developed for blind estimates of pseudo-random code(PC) rates and symbol periods of direct sequence spread spectrum(DS/SS) signals in low signal to noise ratio environments.The ability of the HWT to characterize and detect phase jumps of DS/SS signals was analyzed to formulate the HWT of DS/SS signals.The characteristics of the HWT spectra of the DS/SS signals were analyzed to extract the two HWT parameters.Simulation results with a data set having 400 symbol lengths and a spread factor of 63 show that the PC rate and symbol period algorithm works well with SNR of-18 dB and-14 dB,with better performance than some representative algorithms.