高动态卫星DSSS信号Turbo迭代捕获算法  

Turbo iterative acquisition algorithm for satellite high-mobility DSSS signal

作　　者：姜春晓[1,2] 王佳蔚 JIANG Chunxiao;WANG Jiawei(Beijing National Research Center for Information Science and Technology,Tsinghua University,Beijing 100084,China;Tsinghua Space Center,Tsinghua University,Beijing 100084,China;Department of Electronic Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学国家信息与科学技术研究中心,北京100084 [2]清华大学宇航中心,北京100084 [3]清华大学电子工程系,北京100084

出　　处：《通信学报》2021年第8期15-24,共10页Journal on Communications

基　　金：国家重点研发计划基金资助项目(No.2020YFB1804800);国家自然科学基金资助项目(No.61922050)。

摘　　要：针对高动态卫星通信中捕获概率受限且计算复杂度大的问题,提出了高动态信号捕获的因子图模型,在模型中将时变多普勒变化率建模为随机游走模型,并进一步提出了Turbo双环迭代捕获算法。在多普勒消除环路中,通过消息传递的方式进行多普勒频偏和多普勒变化率的补偿以消除时变多普勒频偏的影响,同时在码字判决环路中,利用扩频序列码片间的约束关系从接收序列中恢复出发送序列,从而进行迭代判决。仿真结果表明,所提算法相比于传统算法在高动态环境下至少有1.3 dB的捕获性能提升,同时复杂度相对较低。To solve the problems of the low acquisition probability and high computational complexity in satellite high-mobility communications, a new factor graph was designed for acquisition of the high-mobility direct sequence spread spectrum(DSSS) signal, where time-varying Doppler rates were modeled by the random walk model. Based on the proposed factor graph, the turbo iterative DSSS signal acquisition algorithm was proposed. In the Doppler-estimation loop, the negative influence of Doppler frequency offsets and Doppler rates could be eliminated effectively. Then in the code-detection loop, constraints of each chip was used to recover the received signal, to achieve DSSS signal acquisition. Simulation results show that the proposed algorithm is capable of improving the acquisition performance at less 1.3 dB with low computational complexity.

关 键 词：M序列 高动态通信 因子图 消息传递 

分 类 号：TN914[电子电信—通信与信息系统]