Low complexity complex matrix inversion method for MIMO communication systems

In multiple-input multiple-output (MIMO) communication systems, complex matrix inversion is a very computationally demanding operation. Especially when the number of antennas increases, i.e., in a massive MIMO system, the complexity of matrix inversion becomes very high. Motivated by this observation, a new low complexity complex matrix inversion method, called SDF-SGR (Square root and Division Free Squared Givens´ Rotations) based algorithm, is designed for MIMO channels. Square root operation is avoided in the whole algorithm, and division operation is replaced by shift operation during the Givens´ rotations phase. Besides, since the scale factor z, involved in the traditional SGR, has little influence on the whole algorithm, it is removed in this SDF-SGR algorithm. Considering a 4×4 complex matrix inversion, the SDF-SGR based algorithm could reduce the multiplication operations by 13.07% compared with the traditional SGR algorithm, and the division operation is reduced by almost 52.94%.