中文摘要：

为提高无线通信网络的频谱效率，提出一种自适应空时分组编码波束成形（STBC-beamforming）跨层设计方案．该方案利用自适应编码调制技术与混合自动重传技术交互协作，使发射端可以根据反馈延时信息自适应调节调制模式，选择发射权以及自动重传数据．推导了系统在时延反馈条件下的频谱救率和中断概率的闭合表达式，分析了时延反馈对系统性能的影响．仿真结果表明，对比单发／单收跨层系统和Alamouti’s跨层系统，自适应STBC-beamforming跨层系统的性能有明显提高．

英文摘要：

An adaptive space time block code （STBC） Beamforming cross-layer design scheme is proposed to improve wireless communication network＇ s spectral efficiencies. The scheme is scheduled through combining multi-level adaptive modulation and coding with hybrid automatic repeat request protocol. The transmitter updates the modulation mode, chooses the optimal transmission vector adaptively and retransmits data automatically by outdated feedback information. The close-form expressions of cross-layer system for spectral efficiencies and the probability of outage under outdated feedback are obtained. Effects of outdated feedback on system＇s performance are analyzed. Simulations show that, compared to single-input-single-output （SISO） cross-layer system and Alamouti＇ s cross-layer system, the performance of the adaptive STBC-Beamforming cross-layer system is observably enhanced.