基于5G标准的低轨卫星通信初始同步技术

Initial Synchronization Technology of Low Orbit Satellite Communication System Based on 5G Standard

在低轨卫星通信系统中,初始同步技术是其至关重要的一步,而由于低轨卫星信道的大多普勒频偏等原因影响了信号的同步性能,为了减少影响,借鉴地面5G初始同步算法,在PSS检测中进行本地PSS整数频偏处理,扩大了频率估计范围,减少了初始同步时间,其正确检测率比传统算法提高了1.5 dB;在小数倍频偏估计中,采用分段处理的PSS差分互相关算法,其精确度相较于传统算法,提高了1~2 dB;最终通过仿真可知,该算法可以在高动态、低信噪比环境下完成初始接入过程的同步信号检测,可以满足低轨卫星通信系统的下行同步要求。

In the low-orbit satellite communication system,the initial synchronization technology is a crucial step,and the signal synchronization performance is affected by the Doppler frequency offset of the low-orbit satellite channel.In order to reduce the impact,the ground 5G initial synchronization algorithm is used for reference,Perform local PSS integer frequency offset processing in PSS detection,expand the frequency estimation range,reduce the initial synchronization time,and its correct detection rate is 1.5dB higher than the traditional algorithm;in the fractional frequency offset estimation,the segmented processing is used Compared with the traditional algorithm,the accuracy of the PSS differential cross-correlation algorithm is improved by 1 to 2dB.Finally,simulation shows that the algorithm can complete the synchronization signal detection of the initial access process in a high dynamic,low signal-to-noise ratio environment,and can meet the downlink synchronization requirements of the low-orbit satellite communication system.