基于联合梳状搜索的空间通信载波多普勒频偏捕获算法  

A joint⁃comb⁃search based carrier Doppler⁃shift acquisition algorithm in space communications

作　　者：张兆维 刘琳 刘慧 师晓晔[1] 潘甦[1] ZHANG Zhaowei;LIU Lin;LIU Hui;SHI Xiaoye;PAN Su(School of Internet of Things,Nanjing University of Posts and Telecommunications,Nanjing 210003,China;School of Software Engineering,Jinling Institute of Technology,Nanjing 211169,China)

机构地区：[1]南京邮电大学物联网学院,江苏南京210003 [2]金陵科技学院软件工程学院,江苏南京211169

出　　处：《南京邮电大学学报（自然科学版）》2023年第6期1-10,共10页Journal of Nanjing University of Posts and Telecommunications：Natural Science Edition

基　　金：国家自然科学基金(61801236);南京邮电大学校级自然科学基金(NY222161);江苏省研究生科研与实践创新计划(SJCX23_0288)资助项目。

摘　　要：在空间通信中,远距离信号传输和高速载体运动导致很低信噪比和高动态多普勒频偏。为捕获载波多普勒频偏,一方面,低信噪比要求长时间信号累积以聚集能量;另一方面,高动态多普勒频偏在长时间累积过程中导致严重的能量扩散问题。为此,提出一种基于联合梳状搜索(Joint-Comb-Search,JCS)的多普勒频偏捕获算法。借鉴联合检测和梳状滤波器思想,JCS算法首先建立多个累积周期并从中选择若干个较大元素,然后据此联合构造一个更小的梳状搜索范围,最后在此范围内搜索最大元素作为捕获结果。基于卡方分布,比较了噪声元素和信号元素并推导出捕获概率的理论表达式。理论分析和仿真结果表明,JCS算法能够从梳状搜索范围中滤除大部分噪声元素,从而显著地提高多普勒频偏捕获概率。In space communications,the long⁃distance transmission and the vehicles high⁃speed motion cause the low signal⁃noise ratio(SNR)and the dynamic Doppler⁃shift on the carrier frequency.To acquire the Doppler⁃shift,the low SNR requires the long⁃time accumulation to accumulate the energy,but the dynamic Doppler⁃shift leads to the serious energy dispersion problem during the long⁃time accumulation period.A joint⁃comb⁃search(JCS)based Doppler⁃shift acquisition algorithm is proposed to solve this problem.Based on the joint⁃detection and comb⁃filter ideas,the JCS algorithm first builds multiple accumulation periods and selects some large elements,then uses these elements to jointly construct a narrower comb⁃search⁃range.Finally,it searches the largest element as the acquisition result in this range.Based on the chi⁃square distribution,this paper compares the noise elements with the signal elements and derives the theoretical expression for acquisition probability.The theoretical analysis and simulation results show that the JCS algorithm excludes most noise elements out of the comb⁃search⁃range,thus significantly increases the Doppler⁃shift acquisition probability.

关 键 词：空间通信 多普勒频偏捕获 能量扩散 联合检测 梳状搜索 

分 类 号：TN929.5[电子电信—通信与信息系统]