在Grassmann流形上构造非相干酉空时码

摘要

研究基于Grassmann流形的非相干酉空时星座图的设计方法。首先定义了非相干空时码在流形上的酉矩阵框架结构；然后在此框架约束下，将已有的Grassmann流形上最优包络分布的最小Frobenius弦距离作为阈值，通过设置合适的步长来改变酉矩阵中各元素的幅值和相位，在流形上搜索最小 Frobenius 弦距离大于阈值的点，搜索到事先设定的星座图点数，即构成酉空时星座图。数值仿真结果表明本框架结构非相干Grassmannian酉空时码的性能均优于现有的其他形式非相干酉空时码的性能。%A novel search technique was presented for designing noncoherent unitary space-time constellation. First of all, a unitary matrix framework based on Grassmann manifold was defined. Under the constraint of this framework, a dis-tance threshold was set by using the existing minimum chordal Frobenius norm of optimal packing distribution on the Grassmann manifold, and the points were searched for whose minimum chordal Frobenius norm exceeds the threshold by changing the amplitude and phase of every entry in the unitary matrix. At last, the whole unitary space-time constellation with minimum chordal Frobenius norm maximum was gotten. Numerical simulations indicate that this new constellation perfor better than the present codes.