差分酉空时调制(DUSTM)是一种应用于时变衰落信道下的多天线调制方法。该方法在慢衰落信道下无需知道信道状态信息而能获得全发送分集增益。但是,在快速衰落信道下,其性能明显恶化并且呈现出较高的误码平层。该文通过在差分酉空时调制中引入矩阵分割和子矩阵交织等操作提出了一种基于子矩阵交织的差分酉空时调制(SMI-DUSTM)方案,并对其性能进行了分析。性能分析和相应的计算机仿真证明了SMI—DUSTM不仅能够继承DUSTM在慢衰落信道下的优点,而且在快速衰落信道下能够保持良好的系统性能。
Differential Unitary Space-Time Modulation (DUSTM), which is a multi-antenna modulation technique for time-varying fading channels, can obtain full diversity gains without channel state information at the receiver in slowly fading channels. For fast fading channels, however, its performance degrades considerably and suffers an irreducible error floor. In this paper, a novel Sub-Matrix Interleaved Differential Unitary Space-Time Modulation (SMI-DUSTM) scheme is proposed, in which matrix-segmentation and sub-matrix based interleaving are combined with conventional DUSTM. The constellation design criteria of SMI-DUSTM are also derived in this paper, based on the calculation of Pairwise Error Probability (PEP). The performance analysis and simulation results demonstrate that SMI-DUSTM can not only inherit the merit of DUSTM in slowly fading channels, but also maintain a good performance in fast fading, channels.