分布式空时编码系统中的资源分配技术-通信与信息系统专业论文.docxVIP

摘 摘 要 摘 要 协作通信技术的提出是为了解决移动台由于体积、功率等限制无法利用多天 线技术的问题。多个单天线的移动节点相结合所形成的虚拟 MIMO 系统与空时编 码相结合构成的分布式空时编码协作系统（Distributed Space Time Coding，DSTC）， 在获得空间分集增益的同时，进一步提升系统的传输性能，因而得到了很多研究 人员的普遍关注。 本文面向放大转发分布式空时编码协作系统，进行了资源分配技术的研究， 具体包括功率分配、中继选择以及天线选择三个方面。本文的主要贡献包括：1） 针对单/双中继分布式空时编码系统，在保证总功率一定的情况下，提出一种基于 系统最小误码率的功率分配算法，得到系统两个阶段最佳功率分配的闭式解。仿 真结果表明，该算法在中继节点距离源节点或目的节点较近的情况下将明显提升 系统性能；2）为了克服了实时中继选择中传输效率低以及传统固定中继选择计算 复杂度较高等缺点，提出一种基于最佳中继位置的固定中继选择算法，该算法可 有效降低中继选择的复杂度；3）针对单/双中继系统提出相应的发射端天线选择算 法，并且理论分析了所提算法下单中继系统的分集度和双中继系统的误码率。仿 真结果表明，单中继天线选择算法可以使系统的分集度达到满分集，双中继天线 选择算法相对于传统天线选算法可以在系统计算复杂度、传输效率以及性能之间 得到很好的平衡。 关键字：协作通信 分布式空时编码 功率分配 中继选择 天线选择 Abstract Abstract Abstract Cooperative communication technology is proposed to take the advantage of multi-antennas considering the size and power limitation of the mobile units. Distributed space time coding, the combination of space time coding and virtual MIMO systems consisting of multiple single-antenna mobile nodes, has attracted many attentions of researchers due to its transmission performance improvement and the spatial diversity gain. We investigate the resource allocation technology for cooperative communication system with amplify and forward distributed space-time coding (AF-DSTC). Specifically, power allocation, relay selection and antenna selection are investigated. Main contributions of this thesis are: 1) A SER-minimization based power allocation algorithm is proposed under the power constraint. Moreover, the closed-form solution of the optimal two-stage power allocation is derived. Simulation results show that the performance can be improved greatly when the relay is close to resource node or destination node. 2) We propose a relay selection algorithm based on the optimal relay distance, in order to overcome the low transmission efficiency in real-time relay selection schemes and the high computational complexity in traditional fixed relay selection schemes. The proposed algorithm can reduce the complexity of the relay selection. 3) Th