中继增强型多基站协同传输系统的性能分析与方案设计

In this project, the theoretical analysis of the performances will be investigated for the coordinated base stations enhanced by relays, moreover the transmission schemes are optimized for this system. First of all, the performance analysis will be carried out for the above mentioned system from the theoretical point of view for the one-way and two-way relaying protocol, respectively, where the multi-input and multi-output (MIMO) technique will be researched. In particular, the ideas of the green communications are firstly introduced to the above mentioned system, where the energy efficiency and the power saving protocols will be carefully examined by the theoretical performance analysis. Then, considering the above two relaying protocols, the transmission schemes will be optimized to improve the system's performances for the one user and the multi-user scenarios, respectively, where the mathematical theories including convex optimizations and statistics analysis are involved for the optimizations. In particular, the MIMO-OFDM (orthogonal frequency division multiplexing) technique in this system with the two-way relaying protocol will be carefully examined, where the design of the following key schemes will be optimized, including the optimum MIMO precoding, the optimum joint power allocation for MIMO, the limited feedback for MIMO, the multi-user MIMO schedule, the subcarrier matching issue for OFDM, and the allocation of the bit and the power for OFDM. Finally, according to the obtained theoretical performance analysis, the obtained transmission schemes will be re-optimized to reduce the involved computational complexity, the implementation method in the distributed rather than the centralized way, the robustness and the feedback overhead of the channel state information. Therefore, the more practical transmission schemes would be obtained for the system of the coordinated base stations enhanced by relays, which indicates that they could be applied in the next generation of the wireless communications.

研究中继增强型多基站协同传输系统的理论性能分析，并优化设计系统的具体传输方案。首先分别针对单向和双向中继转发协议，结合多输入多输出技术，对中继增强型多基站协同传输的性能参数进行全面深入的理论分析；特别地，将"绿色通信"的理念引入到该系统中，重点研究能量有效性和功率节省协议的理论分析。然后分别针对单用户和多用户通信场景，考虑单向和双向两种不同的中继转发协议，通过凸优化、统计分析等数学方法对中继增强型多基站协同传输方案进行优化设计，从而显著提高通信性能；特别地，重点研究双向转发协议下系统的MIMO-OFDM技术，包括最优预编码、最优功率分配、有限反馈、MIMO多用户调度、子载波匹配、比特功率加载等方案的优化设计。最后根据理论分析结果对已设计出的具体传输方案从低复杂度、分布式实现方式、信道状态信息有限反馈等方面进行再优化，最终得到更为实用的中继增强型多基站协同传输方案，从而应用于下一代移动通信。

在国家自然科学基金“中继增强型多基站协同传输系统的性能分析与方案设计”(项目号61201172)的支持下，我们在过去的三年时间里实现一系列关于中继增强型多基站协同传输的技术突破。成功研究出两个小区旁听干扰的新型协同发射协议，并针对新协议优化设计了中继站最优放大转发预编码技术；成功设计出高能效的中继站辅助的基站发射功率分配方案，该方案实现了系统的能量效率最高的优越性能；设计出单天线的两跳无线信道的联合功率分配方案，并理论证明了该方案具有能量效率的渐进最有性能；设计出双向中继的干扰抑制的预编码方法，该方法适用于任意多根发射天线的系统场景，并适用于信道状态信息带有误差的实际通信场景；设计出单小区中继辅助的上行用户和下行用户共存的新型传输协议，优化得到新协议下的中继放大转发预编码技术；利用大尺度衰落特定设计出三小区两时隙传输的新型协议，并设计出新协议中每个基站在连续两个时隙的时域预编码矢量。总共产生学术论文46篇，其中SCI论文17篇，最佳论文奖2篇，发明专利申请15项，获授权2项，以项目负责人为第一作者发表的高质量国际知名SCI论文12篇。