5G卫星通信系统频偏估计算法

A Frequency Offset Estimation Algorithm for 5G Satellite Communication System

卫星通信系统中存在的大的多普勒频偏严重影响着系统的性能。为了提高频偏估计的性能,基于5G NR帧结构和同步信号,提出新的利用级联积分梳状(Cascaded Integrator Comb,CIC)滤波器插值的小数倍频偏估计算法。该算法分两步实现小数倍频偏估计:首先,利用结构简单、运算快速的CIC滤波器对接收主同步序列(Primary Synchronization Signal,PSS)信号和本地PSS进行插值处理,以增加采样点;然后,使用基于PSS的互相关算法估计频偏。算法分析和仿真结果表明,所提算法相较于基于PSS的互相关方法可以取得更好的估计准确度,具有很强的实用性。

The large Doppler frequency offset in satellite communication system seriously affects the performance of the system.In order to improve the performance of frequency offset estimation,based on 5G frame structure and synchronous signal,a new fractional frequency offset estimation algorithm using integral cascade comb(CIC)filter interpolation is proposed.The algorithm is divided into two steps to realize fractional frequency offset estimation.Firstly,the CIC filter with simple structure and fast operation is used to interpolate the received main synchronous sequence(PSS)signal and the local PSS to increase the sampling points,and then the cross correlation algorithm based on PSS is used to estimate the frequency offset.Algorithm analysis and simulation results show that the proposed algorithm can achieve better estimation accuracy than cross-correlation method based on PSS,so it has strong practicability.