摘要
给出了几个关于非相干多输入输出系统的新的编码.在高信噪比的情况下,非相干空时编码问题等价于在格拉斯曼流型上的存储问题;通过指数映射,它被进一步简化成相干情况下的多输入输出系统的空时编码问题.在相干和非相干编码中,对于每个信号的平均发送功率有不同的考虑.通过改造已有的相干空时编码或者选择新的信号设计,我们构造出一些新的非相干空时编码.模拟计算表明,新码有更好的表现.与此同时,新码也全部运用了系统自由度.这意味着它们具有高光谱效率.
Space-time code designs for non-coherent MIMO(multiple input multiple output) systems are studied. At high signal to noise power ratio region (SNR), the non-coherent space-time code designs are equivalent to the packing in Grassmann manifold. By viewing Grassmann manifold as the image of exponential mapping over the tangent space at the identity point, it is further simplified as conventional coherent space-time code designs. We point out that the average transmission power per symbol (isnt) an issue for non-coherent space-time code designs while it is very important for coherent cases. The existing coherent space-time codes is modified to make them suitable for non-coherent space-time design. Two new codes are proposed and performance comparisons with existing codes are presented. The new codes fully employ the (systems) degrees of freedom, which means they have high spectral efficiency.
