无线协同中继系统中的自适应调制策略

Adaptive Modulation Strategy in Wireless Cooperative Relaying Systems

协同中继技术由于其较易实现及在提高系统性能方面的有效性,成为未来移动通信系统中一项很有竞争力的技术。目前的自适应调制研究局限在放大转发系统的自适应,或者只针对部分链路进行自适应。本研究针对译码转发系统进行了自适应调制策略的设计,并且综合考虑各条链路的信道状况进行发送端与中继端调制方式的自适应选择。通过互信息的方式对目的端不同调制方式的合并信号进行性能预测,以用于调制方式的选择。仿真结果表明本文提出的自适应调制策略能够有效的提高系统吞吐量。

Cooperative relaying has become one promising technology in mobile communication systems for its easy implement and effective performances. Different from previous studies which either focused on adaptive strategies in Amplify -and -Forward systems or didnt make full use of the variable channels, a research of the adaptive modulation strategy based on Decode - and - Forward systems is made, where modulation schemes in source and relay are selected according to all the communication links. Performance prediction of combining signals from source and relay which may adopt different modulation schemes is solved by mutual information calculation, and the prediction results serves for modulation schemes selection. Simulation results prove the effectiveness of the proposed strategy in improving system throughput.