协作通信中的解码转发中继策略优化

在单中继协作通信系统模型下，研究了直接传输、固定解码转发（ DF）中继、选择DF中继和增量中继协议。为了提高协作通信系统的频谱效率和中断性能，通过比较源-目的端和中继-目的端的瞬时信道增益来判定是否需要采用协同通信模式，提出一种改进的解码转发方式（ IDF）。通过将选择DF中继和增量中继的优点结合，提出了一种增量选择中继（ ISR）策略，并给出了2种改进协议任意信噪比的中断概率表达式。仿真结果表明，与传统的单中继解码转发协议相比， IDF和ISR均具有更低的中断概率， ISR具有最低的中断概率。

Relay Strategy Optimization of Decode-and-Forward in Cooperative Communication System

The direct transmission（DT）,fixed decode-and-forward（DF）relaying,selective DF relaying（SR）and incremental relaying （IR）protocols are studied over the single relay cooperative communication system model.In order to enhance the spectral efficiency and outage performance in cooperative communication system, an improved decode-and-forward （ IDF ） method is proposed. Whether the IDF method adopting the cooperative communication model or not bases on the comparison about the instantaneous channel gains of source-to-destination with that of relay-to-destination.Moreover,an incremental selection relaying（ISR）is proposed,combining the advantages of SR and IR.The outage probability expressions of the improved protocols at arbitrary SNR are also given in the paper.Simulation results show that,compared with traditional single relay DF,IDF and ISR have lower outage probability.And ISR has the lowest outage probability.