联合HARQ和AMC中继系统跨层优化设计

为了提高协作中继系统频谱效率性能,对Nakagami-m衰落信道中联合物理层自适应调制编码(AMC)和链路层混合自动请求重传(HARQ)协议跨层设计方法进行研究.首先提出一种状态转移图来分析计算协作中继系统的误包率(PER);然后建立了最大化系统频谱效率的跨层优化模型,并给出迭代求解算法;最后对3种HARQ协议下中继系统性能进行对比分析.仿真结果表明,协作中继系统的性能明显优于非中继协作系统,联合Ⅲ型HARQ的跨层设计可实现比联合Ⅰ型和联合Ⅱ型HARQ更高的频谱效率和更低的PER.

Cross-Layer Optimization and Design of Combining Hybrid ARQ with AMC in Cooperative Relay System

To improve spectral efficiency in cooperative relay system,a cross-layer optimization scheme is proposed,that combines adaptive modulation and coding(AMC) at physical layer with hybrid automatic repeat request(HARQ) at data link layer based on Nakagami-m fading channel.A state transition model is used to analyze and calculate the average packet error rate(PER) of cooperative relay system.To maximize the average spectral efficiency under the constraints of PER and transmission delay,the cross-layer optimization model by using iteration algorithm is solved,and the average PER and spectral efficiency of three types of HARQ protocol is compared.It is shown that the system performance of cooperative relay system is much better than that of non-cooperative relay system.In addition,the cross-layer design scheme combining type-III HARQ can achieve higher spectral efficiency and lower PER than type-I,II HARQ.