低轨卫星通信系统OFDM传输技术研究

项目名称： 低轨卫星通信系统OFDM传输技术研究

项目编号： No.61301131

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 无线电电子学、电信技术

项目作者： 那振宇

作者单位： 大连海事大学

项目金额： 23万元

中文摘要： 尽管正交频分复用（OFDM）技术有很多优势，但是将其作为低轨卫星通信传输体制仍然有很多问题亟待解决，究其原因主要是资源受限的低轨卫星通信中存在频繁的波束切换、信道时变特性、多径衰落以及由多普勒频移导致的载波频率偏移，现有针对卫星通信系统OFDM传输技术的研究不能满足用户对服务质量的要求。本项目针对低轨卫星通信特点，首先，建立低轨卫星通信系统OFDM链路模型，论证所提模型的合理性。然后，从物理层出发，以减小时延和提高算法精度为目标，针对信道时变性，提出快速收敛的上行链路单用户信号检测方法；针对载波频偏干扰，提出基于改进并行干扰消除的上行链路多用户检测机制；针对多径衰落和载波频偏干扰，提出联合信道和频偏的下行链路干扰消除算法；针对带宽受限，提出下行链路的信号盲检测机制。最后，从链路层角度，并结合物理层，提出能够满足用户不同QoS需求的功率控制方法。

中文关键词： 低地球轨道；正交频分复用；卫星通信；信号传输；

英文摘要： Although OFDM (Orthogonal Frequency Division Multiplexing) technology has many advantages, as transmission scheme for LEO (Low Earth Orbit) satellite communication, there are still a lot of issues to be discussed mainly because LEO satellite communication not only has limited resources, but also it suffers from frequent beam switches, time-varying channel, multi-path fading and large frequency offset. Current OFDM transmission technology for satellite communication cannot meet users' QoS (Quality of Service) requirements. First, according to characteristics of LEO satellite communication, this project establishes OFDM transmission link models for LEO satellite communication and proves the rationality. Second, from physical layer taking delay and algorithm precision as optimized objectives, single-user signal detecting method according to time-varying channel for uplink is proposed; multi-user detecting scheme based on improved parallel interference cancellation according to frequency offset interference for uplink is proposed; improved interference cancellation algorithm for downlink to cancel the interference introduced by frequency offset and multi-path fading is proposed; signal blind detecting method for downlink to increase bandwidth utilization is proposed. Third, from both link layer and physical layer, p

英文关键词： LEO；OFDM；satellite communication；signal transmission；