Joint timing and frequency synchronization algorithm of LEO satellite communication system

doi:10.7523/j.ucas.2024.053

Abstract

Abstract:

The integration of low earth orbit （LEO） satellite with 5G in the mobile communication system presents extensive application prospects. To ensure effective establishment of communication links between users and base stations， as well as reliable data transmission， time-frequency synchronization technology plays a crucial role. However， traditional timing and frequency synchronization algorithms face limitations when dealing with millimeter wave frequency bands， large bandwidths， high Doppler frequency shifts and change rates， and low signal-to-noise ratios in low-orbit satellite channels. These limitations result in decreased estimation accuracy. For the uplink service data channel of a 5G-based low orbit satellite communication system， a joint timing and frequency synchronization algorithm based on weighted embedded synchronization sequences is proposed to improve the accuracy of timing and frequency offset estimation. Simulation results demonstrate that the proposed timing and frequency synchronization algorithm outperforms traditional algorithms with comparable complexity in terms of synchronization performance.

Key words: LEO satellite communication, OFDM, time synchronization, frequency synchronization

CLC Number:

TN927+.23

Yanping LI, Lin SHANG, Guotong LI. Joint timing and frequency synchronization algorithm of LEO satellite communication system[J]. Journal of University of Chinese Academy of Sciences, 2026, 43(2): 218-229.

Figures/Tables 8

Fig.1 Block diagram of uplink data channel

Fig.2 Slot structure of uplink user data transmission

Fig.3 Block diagram of received sequence difference matrix

Fig.4 Satellite beam cell

Table 1 Simulation parameters

仿真参数	参数配置
系统有效带宽/MHz	46.08
载波频率 $f c$ /GHz	30
子载波间隔/kHz	120
调制方式	QPSK
IFFT点数（ $N$ ）	512
CP长度（ $N C P$ ）	36
归一化CFO（ $ε$ ）	0.05
STO（ $θ$ ）	12
PN序列	Gold序列
仿真次数	12 000

Table 1 Simulation parameters

仿真参数	参数配置
系统有效带宽/MHz	46.08
载波频率 $f c$ /GHz	30
子载波间隔/kHz	120
调制方式	QPSK
IFFT点数（ $N$ ）	512
CP长度（ $N C P$ ）	36
归一化CFO（ $ε$ ）	0.05
STO（ $θ$ ）	12
PN序列	Gold序列
仿真次数	12 000

Fig.5 Normalized timing measure function curve of joint double correlation algorithm for multiple difference interval accumulations

Fig.6 Comparison of estimation performance of timing and frequency offset

Fig.7 Comparison of estimation performance of timing and frequency offset （M1=1，M2=4）

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