| 摘要: |
| 针对低轨卫星环境中的较广波束覆盖范围和较大多普勒频移的特点，研究了能够应用于低轨LTE（Long Term Evolution）卫星移动通信中的随机接入前导及其检测算法。首先，提出多根长序列（MRLS），该序列通过级联多个根序列号不同的短ZC（Zadoff-Chu）根序列构建，可以支持一步定时提前估计；其次，提出一种基于MRLS的随机接入前导检测算法，该算法通过相邻短ZC根序列的共轭相乘产生多个检测序列，再与多个待检序列进行联合差分相关检测，克服了整数倍和小数倍子载波间隔的多普勒频移的影响。仿真结果表明，利用MRLS序列，所提算法对载波频率偏移具有很好的鲁棒性，适用于基于LTE的低轨卫星移动通信系统。 |
| 关键词: 低轨卫星 卫星移动通信 LTE 随机接入 多普勒频移 前导检测 |
| DOI： |
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| 基金项目:国家自然科学基金资助项目（61775237，61675232） |
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| Research on preamble design and detection algorithm for random access in LTE-based LEO satellite |
| DING Rui,LIU Zhao,ZHEN Li,QIN Hao |
| (China Academy of Space Technology,Beijing 100094,China;School of Telecommunication Engineering,Xidian University,Xi′an 710071,China) |
| Abstract: |
| To deal with the wide beam coverage and large Doppler frequency shift in the Low Earth Orbit(LEO) satellite environment,this paper addresses the issue of random access preamble design and detection method for the Long Term Evolution(LTE)-based LEO satellite mobile communication systems.A Multiple Root Long Sequence(MRLS) is first presented by cascading multiple different short Zadoff-Chu(ZC) root sequences,which can support one-step timing advance estimation.Subsequently,a novel preamble detection method is proposed based on MRLS.The approach generates the multiple detection sequences by conjugated multiplication of the adjacent short ZC root sequences,and then uses the detection sequences and the pending sequences to carry out the joint differential correlation detection,so that the impact of Doppler frequency shift corresponding to the fractional and integral sub-carrier interval is effectively eliminated.Simulation results demonstrate that,by utilizing MRLS,the proposed method achieves perfect robustness to carrier frequency offset,and consequently can be adopted in LTE-based LEO satellite mobile communication systems. |
| Key words: LEO satellite satellite mobile communication LTE random access Doppler frequency shift preamble detection |
