OFDM协作通信中基于子载波映射的自适应传输策略

Adaptive Transmission Scheme for Cooperative OFDM Networks Based on Subcarrier Mapping

在放大转发的OFDM协作通信网络中,由于第一跳传输(源节点到中继节点)与第二跳传输(中继节点到目的节点)的信道存在独立性,因此合适的子载波映射策略可以有效地提高信道容量,但存在着低信噪比情况下性能恶化的问题。提出了一种基于子载波映射的自适应传输策略,它利用信道状态信息来调整系统的传输策略,从而使得端到端的系统容量最大化。仿真结果表明,经自适应传输模式调整后,系统的中断概率和误符号率下降,同时信道容量的性能也得到提升。

In amplify-and-forward（AF）OFDM cooperative communication system,since the channel between the first hop（source-relay）and the second hop（relay-destination）varies independently,proper subcarrier mapping（SCM）strategy at the relay node has been shown to improve the average end-to-end capacity evidently.However SCM has a poor performance at the condition of low signal-to-noise-ratio（SNR）,which is worse than direct transmission.To solve this issue,assuming that perfect channel knowledge is available at the destination node,an adaptive transmission scheme based on subcarrier mapping was proposed for the OFDM-based cooperative communications in this paper.The adaptive transmission scheme,which is based on instantaneous channel state information,was selected to offer maximum the end-to-end system capacity.The simulation results show that the proposed solution can evidently improve end-to-end system capacity and achieve better performance of outage probability and symbol error rate.