卫星LTE移动通信适应性技术研究

发布时间：2018-06-30 17:39

本文选题：卫星移动通信 + 卫星信道　；参考：《解放军信息工程大学》2014年硕士论文

【摘要】：卫星移动通信系统具有覆盖区域广、室外信道质量高、抗毁性强等优点,被广泛应用于偏远地区通信网络建设、抢险救灾应急通信、军事通信等领域。随着地面移动通信标准的不断发展,自2011年以来国内外的众多研究机构开展了以长期演进(Long Term Evolution:LTE)技术体制为基础的新一代卫星移动通信系统及其关键技术的广泛研究。我国在十二五规划中更是确立了建立我国自主卫星LTE移动通信系统试验网络的建设目标。目前,针对LTE体制的卫星环境适应性改进技术研究成为这一领域的研究重点,本文的研究工作归属于这一范畴,重点研究了静止轨道(Geostationary Earth Orbit:GEO)卫星移动通信系统中下行链路联合发送技术、上行定时同步技术和SIP(Session Initiation Protocol)会话控制协议的适应性改进技术,完成工作包括:1.针对卫星移动通信与LTE通信体制相融合的关键技术问题展开分析,详细阐述了本文所要研究的MIMO技术、OFDM技术和协议标准的适应性改进问题,分别就卫星LTE系统组成、载荷配置和协议展开分析,通过三种经典的卫星移动通信信道统计模型研究卫星无线信道的传播特性,结合地面MIMO信道容量研究成果给出卫星LTE信道容量计算解析表达式,建立本文性能分析的理论基础;2.针对采用MIMO技术的GEO多波束卫星LTE系统在同频组网时,用户数据随机分布在子载波资源块而形成随机窄带同频干扰问题,首先构建了GEO卫星移动通信系统同频组网的频率复用小区模型,分析了该模型下多波束卫星下行链路联合发送技术的适应性,然后以Lutz卫星移动通信信道统计模型为基础模型,提出一种基于Block-Diagonalization预编码算法的下行联合发送方法,理论分析及仿真结果表明,本文所提方法可使得用户在波束边缘区域获得0.8~1.8bps/Hz的信道容量增益,且算法复杂度较低;3.针对卫星大时延环境下定时误差会破坏OFDM符号正交性的问题,首先对传统卫星定时同步技术展开分析,然后借鉴现有移动通信系统时延误差估计方法的设计思想,通过设计闭环控制的定时误差补偿机制,提出一种基于LMS估计的上行定时同步优化方法,仿真结果表明,本文所提方法在卫星环境下能保证系统的上行定时同步精度满足LTE标准的定时同步要求,且传输速率损失仅为9%,优于现有方法。4.针对传统SIP会话控制协议应用于卫星通信系统时会话建立时延过大的问题,首先参考SkyTerra卫星系统通信系统结构特点,然后引入P2PSIP技术,构建了基于分布式哈希表(Distributed Hash Table:DHT)结构的卫星P2P(Peer to Peer)覆盖层重叠网络模型,提出一种适用于GEO卫星的P2PSIP会话控制机制,利用OPNET软件进行性能仿真验证,其结果表明,本文所提方法能有效减少会话建立过程中用户与信关站间的信令交互次数,减少用户会话建立时延。
[Abstract]:The satellite mobile communication system has the advantages of wide coverage, high quality of outdoor channel and strong survivability. It has been widely used in remote area communication network construction, emergency communications, military communications and other fields. With the continuous development of terrestrial mobile communication standards, many research institutions at home and abroad have carried out extensive research on the new generation satellite mobile communication system and its key technologies based on long term Evolution: LTE (long term Evolution: LTE) technology system since 2011. In the 12th Five-Year Plan, China has established the goal of establishing the experimental network of autonomous satellite LTE mobile communication system. At present, the research of satellite environment adaptability improvement technology based on LTE system has become the focus of this field, and the research work in this paper belongs to this category. The technologies of joint downlink transmission, uplink timing synchronization and session initiation Protocol (SIP) session control protocol in Geostationary Earth Orbit: GEO satellite mobile communication system are studied in detail. Based on the analysis of the key technologies of the convergence of satellite mobile communication and LTE communication system, the adaptive improvement problems of MIMO technology and protocol standard are discussed in detail in this paper. Respectively, the composition of satellite LTE system is discussed. Based on the load configuration and protocol analysis, the propagation characteristics of satellite wireless channel are studied by three classical statistical models of satellite mobile communication channel, and the analytical expression of satellite LTE channel capacity is given based on the research results of terrestrial MIMO channel capacity. The theoretical basis of performance analysis in this paper is established. For GEO multi-beam satellite LTE system with MIMO technology, the random narrowband interference problem is formed when the user data is randomly distributed in the sub-carrier resource block in the same frequency network, so as to solve the problem of random narrowband co-frequency interference in GEO multi-beam satellite LTE system using MIMO technology. Firstly, the frequency multiplexing cell model of GEO satellite mobile communication system is constructed, and the adaptability of multi-beam satellite downlink joint transmission technology under this model is analyzed. Then, the statistical model of Lutz satellite mobile communication channel is used as the basic model. A joint downlink transmission method based on Block-Diagonalization precoding algorithm is proposed. The theoretical analysis and simulation results show that the proposed method can obtain a channel capacity gain of 0.8 ~ 1.8bps-Hz in the edge region of the beam, and the complexity of the algorithm is low. Aiming at the problem that timing error will destroy the orthogonality of OFDM symbols in the environment of large satellite time delay, the traditional satellite timing synchronization technology is analyzed firstly, and then the design idea of the existing methods of time delay error estimation in mobile communication system is used for reference. By designing the timing error compensation mechanism of closed-loop control, a timing synchronization optimization method based on LMS estimation is proposed. The simulation results show that, The method proposed in this paper can ensure the uplink timing synchronization accuracy of the system meets the LTE standard timing synchronization requirements in satellite environment, and the transmission rate loss is only 9, which is superior to the existing methods. 4. Aiming at the problem of excessive delay of session establishment when traditional SIP session control protocol is applied to satellite communication system, firstly referring to the structural characteristics of SkyTerra satellite communication system, then introducing P2PSIP technology. A P2P (Peer to Peer) overlay network model based on distributed hash table (DHT) architecture is constructed. A P2PSIP session control mechanism suitable for GEO satellite is proposed. The performance is verified by OPNET software. The method proposed in this paper can effectively reduce the number of signalling interactions between the user and the signalling station during the session establishment process and reduce the user session establishment delay.
【学位授予单位】：解放军信息工程大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN927.23

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