针对低轨第五代移动通信技术(5G)协议标准、R16协议标准以及基于5G低地球轨道(LEO)宽带卫星通信系统的终端基带芯片研发的迫切需求,在分析了LEO-5G系统的物理广播信道(PBCH)链路结构和下行时频同步总体架构的基础上,文章提出了一种“两块合并分两段互相关”的主同步信号(PSS)检测算法进行粗频偏估计,通过辅同步信号(SSS)相关对频偏进一步估计,并结合小区特定参考信号(CRS)导频信号确定精确同步的LEO-5G下行同步算法与现场可编程逻辑门阵列(FPGA)实现方案。利用Vivado和Matlab软件对算法的可行性与有效性进行了仿真验证,结果表明,该同步算法具有较好的实时性和较高的稳定度,下行时频同步FPGA模块管理信息库(MIB)解析正确率约为83.07%,并且对于进行时序和资源消耗评估的芯片,存储资源消耗仅为11.7%,各项指标均符合要求。

In response to the urgent need for the development of low-orbit 5th Generation Mobile Networks (5G) protocol standards, R16 protocol standards and terminal baseband chips based on 5G low-orbit broadband satellite communication systems, a Primary Synchronization Signal (PSS) detection algorithm of "two blocks combined and divided into two cross-correlation" is proposed for coarse frequency offset estimation based on the analysis of the Low Earth Orbit (LEO)-5G system's PBCH link structure and downlink time-frequency synchronization overall architecture. The frequency offset is further estimated through Secondary Synchronization Signal (SSS) correlation, and combined with Cell-Specific Reference Signal (CRS) pilot signal to determine the precise synchronization LEO-5G downlink synchronization algorithm with Field Programmable Gate Array (FPGA). The feasibility and effectiveness of the algorithm were verified by simulation using Vivado and Matlab. The results show that the synchronization algorithm has good real-time performance and high stability. The accuracy rate of the downstream time-frequency synchronization FPGA module with Management Information Base (MIB) parsing is about 83.07%. The chip storage resource consumption for the evaluation of timing and resource consumption is only 11.7%. All indicators meet the indicator requirements.