After sunspace decomposition, the close form solution of channel matrix could be obtained, according to the orthogonality of signal subspace and noise subspace.

• 然后求出重构信道矩阵的噪声子空间，之后利用信号子空间与噪声子空间正交特性，构造出信道矩阵作为变量的线性方程组，因而可以得到信道矩阵的闭式解。