TD-LTE-Advanced多天线传输模式下的反馈机制研究
发布时间：2019-05-13 16:44
【摘要】：MIMO技术极大地促进了无线通信的发展，，在TD-LTE-Advanced系统中也得到了广泛的应用，下行最多可以支持8层传输，上行最高支持4层传输，并且定义了多达9种多天线传输模式。除MIMO传输技术外，自适应技术是TD-LTE-Advanced系统采用的另一项关键技术，eNodeB根据UE反馈的CSI信息，为用户选择合适的调制编码方式、合理的传输模式以及预编码矩阵等等，进而更好的适应移动通信的复杂信道变化。然而，这两项关键技术能否完全发挥其作用的关键因素是系统CSI反馈机制的有效性和可靠性。因此，本文对多天线传输模式下TD-LTE-Advanced系统的反馈机制进行了深入的研究。 本文首先研究了TD-LTE-Advanced系统的预编码技术和MIMO检测算法。针对预编码技术，本文依次研究了基于码本的预编码和波束赋形技术，并重点对常用的多用户波束赋形算法进行了仿真分析，经比较，基于SLNR的波束赋形算法能够有效地降低用户间干扰，从而具有更好的性能。之后本文对MIMO检测算法展开研究，并对常用算法进行了仿真分析，通过对检测性能及复杂度的综合比较，选用MMSE算法作为本文接收机的检测算法。在上述研究的基础上，本文又针对不同场景，给出了多小区多天线传输下的SINR的计算公式。 然后，本文对TD-LTE-Advanced标准中规定的9种反馈模式进行了归纳、总结和比较，并在本文搭建的TD-LTE-Advanced的系统级仿真平台上，对与MIMO传输相关的多种反馈模式的性能进行了仿真评估，分析了各种反馈模式的适用性。在此基础上，本文提出了一种提升小区边缘用户性能的反馈模式切换算法，仿真结果显示，采用此切换算法后，在仅增加极小反馈开销的条件下，小区边缘用户的吞吐量得到了有效的提升。 最后，本文利用TD-LTE-Advanced系统上下行信道的互易性，针对慢变信道和快变信道场景，分别提出了CQI频域修正方案和结合信道预测的CQI时频联合修正方案。仿真结果表明，采用本文所提的CQI修正方案可以有效降低系统初始重传率，并提高系统吞吐量。此外，采用CQI修正方案后，使用宽带CQI反馈模式可以获得与子带CQI反馈模式近似甚至更优的性能，从而大大降低了反馈开销。
[Abstract]:MIMO technology has greatly promoted the development of wireless communication and has been widely used in TD-LTE-Advanced systems. Downlink can support up to 8 layers of transmission, uplink can support up to 4 layers of transmission, and up to nine kinds of multi-antenna transmission modes are defined. In addition to MIMO transmission technology, adaptive technology is another key technology used in TD-LTE-Advanced system. ENodeB selects appropriate modulation and coding mode, reasonable transmission mode and precoding matrix for users according to the CSI information fed back by UE. And then better adapt to the complex channel changes of mobile communication. However, the key factor of whether these two key technologies can fully play their role is the effectiveness and reliability of the system CSI feedback mechanism. Therefore, the feedback mechanism of TD-LTE-Advanced system in multi-antenna transmission mode is deeply studied in this paper. In this paper, the precoding technology and MIMO detection algorithm of TD-LTE-Advanced system are studied. Aiming at precoding technology, this paper studies the precoding and beamforming technology based on code book in turn, and focuses on the simulation and analysis of common multi-user beamforming algorithms. The beamforming algorithm based on SLNR can effectively reduce the interference between users, so it has better performance. After that, this paper studies the MIMO detection algorithm, and carries on the simulation analysis to the common algorithm. Through the comprehensive comparison of the detection performance and complexity, the MMSE algorithm is selected as the detection algorithm of the receiver in this paper. On the basis of the above research, the calculation formula of SINR under multi-cell and multi-antenna transmission is given in this paper according to different scenarios. Then, this paper summarizes, summarizes and compares the nine feedback modes specified in TD-LTE-Advanced standard, and on the system-level simulation platform of TD-LTE-Advanced built in this paper, The performance of various feedback modes related to MIMO transmission is simulated and evaluated, and the applicability of various feedback modes is analyzed. On this basis, this paper proposes a feedback mode switching algorithm to improve the performance of cell edge users. The simulation results show that when the switching algorithm is adopted, only the minimum feedback overhead is increased. The throughput of cell edge users has been effectively improved. Finally, based on the reciprocity of uplink and downlink channels in TD-LTE-Advanced system, a CQI frequency domain correction scheme and a CQI time-frequency joint correction scheme combined with channel prediction are proposed for slow and fast variable channel scenarios, respectively. The simulation results show that the CQI correction scheme proposed in this paper can effectively reduce the initial retransmission rate and improve the system throughput. In addition, after the CQI correction scheme is adopted, the performance of the broadband CQI feedback mode can be approximately or even better than that of the subband CQI feedback mode, thus greatly reducing the feedback overhead.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.5
本文编号：2476039
[Abstract]:MIMO technology has greatly promoted the development of wireless communication and has been widely used in TD-LTE-Advanced systems. Downlink can support up to 8 layers of transmission, uplink can support up to 4 layers of transmission, and up to nine kinds of multi-antenna transmission modes are defined. In addition to MIMO transmission technology, adaptive technology is another key technology used in TD-LTE-Advanced system. ENodeB selects appropriate modulation and coding mode, reasonable transmission mode and precoding matrix for users according to the CSI information fed back by UE. And then better adapt to the complex channel changes of mobile communication. However, the key factor of whether these two key technologies can fully play their role is the effectiveness and reliability of the system CSI feedback mechanism. Therefore, the feedback mechanism of TD-LTE-Advanced system in multi-antenna transmission mode is deeply studied in this paper. In this paper, the precoding technology and MIMO detection algorithm of TD-LTE-Advanced system are studied. Aiming at precoding technology, this paper studies the precoding and beamforming technology based on code book in turn, and focuses on the simulation and analysis of common multi-user beamforming algorithms. The beamforming algorithm based on SLNR can effectively reduce the interference between users, so it has better performance. After that, this paper studies the MIMO detection algorithm, and carries on the simulation analysis to the common algorithm. Through the comprehensive comparison of the detection performance and complexity, the MMSE algorithm is selected as the detection algorithm of the receiver in this paper. On the basis of the above research, the calculation formula of SINR under multi-cell and multi-antenna transmission is given in this paper according to different scenarios. Then, this paper summarizes, summarizes and compares the nine feedback modes specified in TD-LTE-Advanced standard, and on the system-level simulation platform of TD-LTE-Advanced built in this paper, The performance of various feedback modes related to MIMO transmission is simulated and evaluated, and the applicability of various feedback modes is analyzed. On this basis, this paper proposes a feedback mode switching algorithm to improve the performance of cell edge users. The simulation results show that when the switching algorithm is adopted, only the minimum feedback overhead is increased. The throughput of cell edge users has been effectively improved. Finally, based on the reciprocity of uplink and downlink channels in TD-LTE-Advanced system, a CQI frequency domain correction scheme and a CQI time-frequency joint correction scheme combined with channel prediction are proposed for slow and fast variable channel scenarios, respectively. The simulation results show that the CQI correction scheme proposed in this paper can effectively reduce the initial retransmission rate and improve the system throughput. In addition, after the CQI correction scheme is adopted, the performance of the broadband CQI feedback mode can be approximately or even better than that of the subband CQI feedback mode, thus greatly reducing the feedback overhead.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.5
【参考文献】
相关期刊论文 前1条
1 孙垂强;葛建华;朱斌;李静;;匹配加权信号泄漏噪声比多用户预编码迭代算法[J];西安电子科技大学学报;2013年04期
本文编号：2476039
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