Modeling research of group delay ripple on the performance analysis oriented to a satellite direct sequence spread spectrum communication system

面向卫星直扩通信体制性能分析的群时延波动建模研究

¹ School of Cybersecurity, Northwestern Polytechnical University, Xi'an 710072, China
² China Academy of Space Technology (Xi'an), Xi'an 710100, China

Received: 18 February 2024

Abstract

This study introduces the group delay and its characteristics in satellite channel, meanwhile, the model of the impact of group delay ripple on performance of direct sequence spread spectrum communication system is established and simulated for analysis. The simulation results indicate the specific impact of group delay ripple on system, as well as the impact of group delay ripple on the transmission and reception signals in the spread spectrum communication system. For transmission signals in the spread spectrum system, the group delay ripple can worsen the EVM and Eye-diagram of spread spectrum signal, cause signal distortion and the deterioration of noise tolerance. For the reception performance of the spread spectrum system, the group delay ripple has little effect on the spread spectrum acquisition using incoherent accumulation and energy judgment, but it can cause a deterioration in the error performance of the reception signal. For example, when relative group delay increases from 0.011 to 0.9, the error performance decreases by about 2 dB. When designing satellite spread spectrum communication systems, power resources are extremely precious, it is necessary to consider the impact of group delay on the communication system, and take certain measures to reduce the impact of group delay ripple to the system.

摘要

介绍了卫星信道群时延及其特性, 建立了群时延波动对直接序列扩频通信(简称“直扩通信”)体制性能影响的模型, 仿真分析了群时延波动对扩频通信体制发射和接收信号质量的影响。对于直扩发射信号, 群时延增大会恶化扩频信号EVM和眼图, 使得发射信号产生畸变, 噪声容限恶化。对于直扩接收性能, 群时延的变化对于采用非相干累加和能量判决的扩频捕获基本无影响, 但是会造成接收信号的误码率性能恶化, 相对群时延从0.011增大到0.9时, 误码率性能损失约2 dB。在设计卫星直扩通信系统时, 功率资源极其珍贵, 必须考虑群时延波动对直扩通信系统的影响, 并采取措施, 降低群时延波动对系统的影响。