Efficient complex matrix inversion for MIMO OFDM systems

The use of orthogonal frequency-division multiplexing (OFDM) greatly simplifies receiver design in multiple-input multiple-output (MIMO) wireless systems when the channel is frequency selective. Since complex-valued matrix manipulations, such as matrix inversion, are normally required in MIMO-OFDM systems, the receiver complexity is much higher than that of single-input single-output and single-carrier systems. In this paper, the authors propose a low-complexity version of matrix inversion by using the dichotomous coordinate descent (DCD) algorithm for MIMO-OFDM systems. The idea is for the DCD algorithm to separately obtain the individual columns of the inverse of the matrix. Owing to the low-complexity hardware implementation of the individual DCD algorithm, a block of DCD processors can be adopted to obtain the columns of the inverse of the channel correlation matrix in parallel with low hardware occupation.