一种适用于散射通信的联合帧同步和频偏估计算法研究

A study of a joint frame synchronization and frequency bias estimation algorithm for tropospheric scattering channels.

摘要:

针对对流层散射通信中存在的多径衰落以及收发两端频偏,对一种适用于对流层散射通信的联合帧同步和频偏估计算法进行了研究；设计了一种适用于对流层散射通信的新型同步帧结构,其在帧同步信息前增加了周期循环PN序列用于辅助判决,能够提高衰落信道下的信号起点捕获概率；采用基于FFT的部分相关频域捕获算法,搜索最大相关值和频偏索引,同时完成了帧同步和频偏估计；在多径衰落和频偏影响下实现了联合帧同步和频偏估计算法；仿真结果表明:在衰落速率5 Hz,频偏1000 Hz散射信道下,正确捕获到帧同步信息概率在-4 dB信噪比下仍可达到90%以上,且频偏估计偏差在0.4 Hz以内

Abstract:

Addressing multipath fading and frequency offset at both transmitter and receiver ends in tropospheric scattering communication,a joint frame synchronization and frequency offset estimation algorithm suitable for tropospheric scattering was studied.Designed a new synchronous frame structure suitable for tropospheric scattering communication,it adds a cyclic PN sequence before frame synchronization information to assist in decision making,it can improve the probability of signal starting point acquisition in fading channels.Adopting a partial correlation frequency domain capture algorithm based on FFT, searching for the maximum correlation value and frequency offset index, while completing frame synchronization and frequency offset estimation.Implemented joint frame synchronization and frequency offset estimation algorithms under the influence of multipath fading and frequency offset;The simulation results show that in a scattering channel with a fading rate of 5Hz and a frequency offset of 1000Hz, the probability of correctly capturing frame synchronization information can still reach over 90% at a signal-to-noise ratio of -4dB, and the frequency offset estimation deviation is within 0.4Hz.