协作分集OFDM系统的混合排序子载波配对算法

A hybrid sorted algorithm for subcarrier pairing in cooperative diversity OFDM systems

考虑到信源子载波和中继子载波的配对能在频率选择信道环境下提高协作分集系统的性能,对协作分集正交频分复用(OFDM)系统的子载波配对进行了研究,推导了2种特殊情况下的最佳子载波配对方法,即顺序配对和逆序配对,在此基础上,提出了一种基于混合排序的子载波配对算法。该算法根据信源-中继链路、信源-标链路和中继-目标链路上的每个子载波的信噪比状态,自适应地选择顺序配对或逆序配对。仿真结果表明,提出的混合排序子载波配对算法能显著提高系统的平均可取得速率,性能明显优于顺序配对和逆序配对。

In consideration of the fact that the performance of a cooperative diversity system can be improved by pairing source subcarriers with relay subcarriers, this paper investigates the subcarrier pairing problem in OFDM-based cooperative diversity systems. Two optimal subcarrier pairing methods are derived under two extreme conditions, respectively, i.e. the order pairing and the reverse order pairing. Further, a hybrid sorted pairing algorithm is proposed, which adaptively selects the order pairing or the reverse order pairing for each subcarrier according to instantaneous SNR conditions of sourcerelay, source-destination and relay-destination links. The simulation results show that the proposed pairing algorithm can enhance the average achievable rate and outperforms the order pairing and the reverse order pairing methods significantly.