一种改进的有限反馈准正交空时编码方案

针对广义正交空时编码利用反馈信道改善系统性能时，由于反馈量的增加导致复杂度较高而失去空时码自身优势的问题，提出了一种改进的有限反馈准正交空时分组编码（QOSTBC）方案，该方案在对编码矩阵对角化重构的同时引入了等效子信道适度旋转设计。结合水声信道模型理论和仿真分析表明，该方案在峰均功率比、实数乘、实数加计算复杂度等方面有较为明显的改进，同时进一步提高了系统的信道容量，降低了系统误码率。

An Improved Scheme for Limited Feedback QOSTBC

The quasi orthogonal space-time block code（QOSTBC） scheme uses feedback channel to improve system performance. Because the increase in amount of feedback results in higher complexity, the space-time code loses its own advantage. In this paper, an improved limited feedback QOSTBC scheme is proposed based on the diagonaliztion reconstruction of encoding matrix and the adequate rotation of equivalent sub-channels. Combining the theory of underwater acoustic channel model and the simulation analysis, it shows that the proposed scheme is significantly improved in such parameters as peak power ratio, computation complexity of real numbers multiplication and real numbers addition. In addition, the system complexity is reduced, the equivalent channel gain is increased, and the bit error rate of system is lowered. Simulation results demonstrate the effectiveness and reliability of the proposed scheme.