结合信号空间分集的双空时发射分集系统

为提高双空时发射分集(DSTTD)系统在独立同分布衰落(IID)信道下的性能，提出一种结合信号空间分集的DSTTD系统，在发射前先对已调信号进行信号空间的旋转映射，提高系统分集阶数。通过矩阵变换获得转换系统传输模型，利用向量高斯近似和标量高斯近似解调算法联合信道译码进行迭代检测，在保证系统性能的同时降低系统解调的复杂度。仿真结果表明，该系统比传统DSTTD系统在IID信道下至少获得2 dB的性能改善。

Double Space-time Transmit Diversity System Combined with Signal Space Diversity

In order to improve the diversity performance of Double Space-time Transmit Diversity(DSTTD) system in Independent and Identically Distributed(IID) fading channels,a DSTTD system combined with Signal Space Diversity(SSD) is proposed.The system can acquire diversity gain by rotation mapping and I-Q branch interleaver.Meanwhile,based on the combined detection method of transmit model system by matrix transformation,the system performance is largely improved by using vector Gaussian approximation and scalar Gaussian approximation for iterative decoding.Simulation results show that the system proposed has 2 dB gain than the ordinary DSTTD system in IID fading channel.