基于三导频帧结构的散射信道载波频偏估计算法  

Carrier Frequency Offset Estimation Algorithm Based on Three Pilot Frame Structure for Troposcatter Channel

作　　者：王栋良[1] 谢峥 赵世铎 WANG Dongliang;XIE Zheng;ZHAO Shiduo(The 54th Research Institute of CETC,Shijiazhuang 050081,China;Poly Technologies,Inc.,Beijing 100010,China)

机构地区：[1]中国电子科技集团公司第54研究所,石家庄050081 [2]保利科技有限公司,北京100010

出　　处：《计算机测量与控制》2025年第3期176-182,共7页Computer Measurement &Control

摘　　要：在对流层散射通信系统中,收发机时钟偏差、散射体随机运动、收发机相对运动等因素都会使接收信号出现载波频率偏移;传统频偏估计算法需要在估计精度和估计范围之间进行取舍,难以获得大范围、高精度的频偏估计,并且由于散射信道固有的快衰落特性,频偏估计算法在散射信道中的统计性能会显著下降;为了解决传统方法存在的问题,对基于分段导频的频偏估计方法进行了研究;将导频分三段插入数据帧中,使用前导频和中间导频获得粗频偏估计,使用前导频和后导频获得细频偏估计,使用粗估计结果对细估计结果进行相位解卷绕,经仿真测试实现了大范围、高精度频偏估计;进一步地,对频偏估计算法与跳频隐分集技术的结合应用进行了研究,经仿真测试验证了该方法在散射信道下的中高信噪比区间内较传统方法可获得2~3 dB信噪比增益,满足散射通信系统实际应用需求。In troposcatter communication systems,it can cause the carrier frequency offset of the received signal for the factors such as clock deviation of transceivers,random movement of scatterers,and relative movement of transceivers.Traditional frequency offset estimation algorithms need to make a trade-off between estimated accuracy and range,making it difficult to obtain the estimation of wide high-precision frequency offset.Additionally,due to the inherent fast fading characteristic of troposcatter channels,it will significantly decrease the statistical performance of frequency offset estimation algorithms in troposcatter channels.In order to solve the problem of traditional methods,a frequency offset estimation method based on segmented pilot is studied.The pilot sequence is divided into three segments and inserted into a data frame,obtains coarse frequency offset estimation by using the head and middle pilots,acquires fine frequency offset estimation by using the head and tail pilots,and adopts the coarse estimation results to perform phase unwrap on the fine estimation results.Simulation results show that this method can obtain wide high-precision frequency offset estimation.Furthermore,the application of combining the proposed algorithm and frequency hopping hidden diversity technology is researched.Simulation results demonstrate that compared with the traditional method,the proposed method can achieve a signal-to-noise ratio(SNR)gain of 2.0~3.0 dB in troposcatter channels with the medium to high SNR range,meeting practical requirements of troposcatter communication systems.

关 键 词：对流层散射通信 频偏估计 导频序列 相位解卷绕 抗衰落 

分 类 号：TP396[自动化与计算机技术—计算机应用技术]