中文摘要：

协作分集技术能够在慢衰落无线环境中提供显著的性能增益。在现有的各种协作分集协议中，分布式空时编码是最有代表性的协作协议。但是由于其复杂性较高，实用性的分布式空时编码的研究仍然面临着很大的挑战。提出了一种新颖的基于机会的分布式空时编码协议，不仅复杂度低，而且可以获取和分布式空时编码协议接近的性能。还针对如何根据中继节点的空间分布进行协作协议选择的问题进行了分析。

英文摘要：

Cooperative diversity can provide dramatic gains in slow fading wireless environments. In all the cooperative diversity protocols, Distributed Space-Time Coding （DSTC） is the most representative. Due to its complexity, the practical distributed space-time coding is still a big challenge. In this paper, the authors introduced a novel cooperative diversity protocol： Opportunistic Distributed Space-Time Coding （ ODSTC）, which could achieve the performance similar to distributed space-time coding, with lower complexity. In addition, the principle to select DSTC or ODSTC was analyzed based on the distribution of relay nodes.