摘要
针对传统星地信道模型及其硬件模拟方法没有考虑卫星姿态对信道特性影响的问题,本文基于几何地理随机模型(Geometry-based Stochastic Model,GBSM)框架,提出了一种融合卫星姿态的星地信道模型。该模型通过构建四个独立的坐标系并引入姿态修正矩阵,来描述卫星姿态变化对星地信道特性造成的影响。在此基础上,本文基于现场可编程门阵列(Field Programmable Gate Array,FPGA),设计并研制了一种星地信道硬件模拟器。硬件模拟器采用差分迭代的算法来生成信道衰落因子,可以极大提高硬件模拟的实时性,确保生成的衰落数据与实际场景相匹配。同时,还采用了并行处理架构,可以支持最大640 MHz带宽的星地信道模拟。为了将衰落数据与并行架构相匹配,引入了并行内插算法,可以将串行的衰落数据内插成同速率的多路并行衰落数据。此外,为了能够精准控制硬件装置输出信号的功率,设计了基于预训练的功率校正方法。通过内部校正源信号预先训练出整个模拟过程给信号带来的增益再进行功率补偿,从而保证输出信号的功率可以被精准控制。最后,在典型场景下开展仿真模拟,导出硬件模拟器的输出结果并分析其统计特性,结果表明实测输出的概率密度函数(Probability Density Function,PDF)和多普勒功率谱密度(Doppler Power Spectral Density,DPSD)与理论值吻合,证明本文设计的硬件模拟器可以准确地复现实际场景下卫星姿态发生变化的星地信道。本文提出的融合卫星姿态的星地信道模型以及研制的硬件模拟器很好地解决了传统模型以及硬件模拟方法的局限性,在卫星通信系统的优化、评估和验证环节具有极大的潜在价值。
To address the issue of traditional satellite-to-ground channel models and their hardware emulation methods that do not consider the impact of satellite posture on channel characteristics,a novel satellite-to-ground channel model that incorporates satellite posture based on the framework of the geometry-based stochastic model(GBSM)is proposed in this paper.The model constructs four independent coordinate systems and introduces a posture correction matrix to accurately describe the influence of satellite posture changes on the satellite-to-ground channel characteristics.Based on this model,a satellite-to-ground channel hardware emulator using a field programmable gate array(FPGA)is designed and developed.The hardware emulator utilizes a differential iteration algorithm to generate channel fading data,significantly enhancing the real-time capability of hardware emulation and ensuring the generated fading data matches the actual scenarios.In addition,a parallel processing architecture is utilized to support satellite-to-ground channel emulation with a maximum bandwidth of 640 MHz.Moreover,a parallel interpolation algorithm is introduced to match the fading data with the parallel architecture.This algorithm interpolates the serial fading data into parallel fading data at the same rate,ensuring accurate emulation of the channel characteristics.Furthermore,to achieve precise control over the output signal power of the hardware device,a pre-trained power calibration method is designed.This method utilizes pre-training with internal calibration source signals to calculate the gain introduced by the entire emulation process,enabling accurate power compensation and precise control over the output signal power.Finally,simulation and analysis are conducted in typical scenarios to derive the output results of the hardware emulator and examine their statistical characteristics.The results demonstrate that the measured probability density function(PDF)and Doppler power spectral density(DPSD)of the output data align closely with
作者
周强军
吕崇玉
陈小敏
华博宇
台鑫
朱秋明
ZHOU Qiangjun;LYU Chongyu;CHEN Xiaomin;HUA Boyu;TAI Xin;ZHU Qiuming(Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space,Ministry of Industry and Information Technology,Nanjing University of Aeronautics and Astronautics,Nanjing,Jiangsu 211100,China;Ceyear Technologies Co.,Ltd,Qingdao,Shandong 266555,China)
出处
《信号处理》
CSCD
北大核心
2024年第6期1019-1029,共11页
Journal of Signal Processing
基金
国家自然科学基金面上项目(62271250)
江苏省自然科学基金(BK20211182)
江苏省重点研发计划(产业前瞻与关键核心技术)(BE2022067,BE2022067-3)
东南大学移动通信国家重点实验室开放研究基金资助课题(2022D04)
实验技术研究与开发项目(SYJS202304Z)。
关键词
星地信道模型
信道模拟
姿态修正矩阵
多普勒功率谱
satellite-to-ground channel model
channel emulation
posture correction matrix
Doppler power spectrum
