LTE-A系统预编码技术和中继资源分配研究

发布时间：2018-08-16 14:16

【摘要】：为了迎接WiMAX等移动宽带无线接入技术市场的挑战,2004年3GPP启动了UMTS标准的长期演进版本-LTE。2008年3GPP开始了面向LTE的平滑演进LTE-A技术的研究。LTE-A引入了多个关键技术,包括载波聚合、中继技术、多天线技术、多点协作技术等。LTE-A多天线系统中可支持发射天线数增加到8天线,在8天线有限反馈系统中3GPP提出双码本预编码技术,双码本预编码码本设计以及码本选择成为LTE-A系统中需要解决的关键问题。同时,LTE-A系统中引入中继技术来提升小区边缘用户性能、增加小区覆盖面积能力。中继传输引入新的传输节点,使得LTE-A系统的结构更加复杂,为了降低中继节点带来的干扰,需要对现有频谱进行合理分配,从而有效提高系统整体容量和边缘用户频谱效率。本文首先介绍LTE-A系统基础知识及关键技术,给出LTE-A系统链路级仿真平台搭建流程图。LTE-A链路级仿真平台是在LTE仿真平台的基础上,根据3GPP 36系列物理层协议添加多输入多输出(Multiple-Input Multiple-Output, MIMO)模式7-9,构建出符合要求的LTE-A链路级仿真平台。论文完成了LTE-A链路级仿真平台的搭建,包括调制编码、预编码、信道产生、信道估计、MIMO解码、结果统计等模块的详细设计说明。链路级仿真平台支持LTE-A标准中的全部MIMO传输模式,其中模式5为多用户传输模式,其他均为单用户模式。然后,论文第三章主要讨论双码本预编码技术,详细介绍了基于DFT固定码本的单码本设计方法和3GPP R10中双码本设计方法,分析固定码本的优缺点,提出一种基于格拉斯曼差分码本的双码本码本设计方案。该方案利用格拉斯曼码本的性质,随着信道信息的变化实时地更新码本集合,使其更好的追踪到信道信息、减小量化误差,从而提高多天线系统性能。文中还讨论了两种双码本选择算法：联合选择算法和两级选择算法,从复杂度、延时和性能等方面进行分析,结果表明两级选择算法优于联合选择算法。接着,论文第四章搭建了LTE-A中继网络系统级仿真平台。LTE-A中继网络系统级仿真平台是在LTE-A传统蜂窝网络的基础上添加中继网络,主要仿真模块包括：中继网络拓扑、用户生成、用户接入、信道模型、调度与自动混合重传(Hybrid Automatic Repear Reques, HARQ)、链路级到系统级(Link- Level to System-Level, L2S)接口映射、上行反馈等。在仿真平台实现后,根据不同的校准场景对系统级仿真进行一致性校准,仿真结果显示与3GPP技术文档结果一致,验证了中继网络系统级仿真平台的有效性。最后,论文针对中继网络资源分配方案进行了研究。在传统蜂窝网络资源分配方案的基础上,提出一种定向中继部分频率复用(Fractional Frequency Reuse, FFR)资源分配方案。此方案中中继传输链路与基站传输链路占用同一可用频带,通过相邻扇区占用交错频带降低中继与基站间的干扰。相比全向中继网络,定向中继能带来更大的系统性能增益。接着本文介绍了三种用户接入算法并对其性能进行分析对比,得出了基于信干噪比接入算法性能最优的结论。
[Abstract]:In order to meet the challenges of the mobile broadband wireless access technology market such as WiMAX, 3GPP launched the long-term evolution version of UMTS standard - LTE in 2004. In 2008, 3GPP began to study the LTE-oriented smooth evolution LTE-A technology. LTE-A introduced a number of key technologies, including carrier aggregation, relay technology, multi-antenna technology, multi-point cooperation technology and so on. In the antenna system, the number of transmit antennas can be increased to 8 antennas. In the 8-antenna limited feedback system, 3GPP proposes the dual codebook precoding technology. The design and selection of dual codebook precoding codebook become the key problems to be solved in LTE-A system. At the same time, the introduction of relay technology in LTE-A system can improve the performance of cell edge users and increase the performance. Cell coverage capacity. The introduction of new transmission nodes in relay transmission makes LTE-A system more complex in structure. In order to reduce the interference caused by relay nodes, it is necessary to allocate the existing spectrum reasonably, so as to effectively improve the overall system capacity and spectrum efficiency of edge users. LTE-A link-level simulation platform is based on LTE simulation platform. According to 3GPP 36 series physical layer protocols, multiple-input multiple-output (MIMO) mode 7-9 is added to construct LTE-A link-level simulation platform. LTE-A chain is completed in this paper. Link-level simulation platform supports all MIMO transmission modes in LTE-A standard, in which mode 5 is multi-user transmission mode and the others are single-user mode. This paper discusses the double codebook precoding technique, introduces the single codebook design method based on DFT fixed codebook and the double codebook design method in 3GP R10 in detail, analyzes the advantages and disadvantages of the fixed codebook, and proposes a double codebook design scheme based on Glassman differential codebook. This paper also discusses two kinds of double codebook selection algorithms: joint selection algorithm and two-stage selection algorithm, which are analyzed from the aspects of complexity, delay and performance. The results show that the two-stage selection algorithm is superior to joint selection algorithm. Secondly, the LTE-A relay network system-level simulation platform is built in the fourth chapter. The LTE-A relay network system-level simulation platform is based on the LTE-A traditional cellular network. The main simulation modules include: relay network topology, user generation, user access, channel model, scheduling and automatic hybrid retransmission (Hy). Brian Automatic Repear Reques, HARQ, Link-Level to System-Level (L2S) Interface Mapping, Uplink Feedback, etc. After the implementation of the simulation platform, the system-level simulation is calibrated according to different calibration scenarios. The simulation results are consistent with the results of 3GPP technical documents, which verifies the system-level simulation of the relay network. Finally, the paper studies the resource allocation scheme for relay networks. Based on the traditional resource allocation scheme for cellular networks, a resource allocation scheme for directional relay partial frequency reuse (FFR) is proposed. The relay transmission link occupies the same available resource as the base station transmission link in this scheme. In order to reduce the interference between the relay and the base station, the directional relay can bring more performance gain than the omnidirectional relay network. Then, three user access algorithms are introduced and their performance is analyzed and compared, and the conclusion that the performance of the algorithm based on SINR is the best is obtained.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN929.5

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