Fourier-transform based linear equalization for MIMO CDMA downlink

摘要

In the reception of a downlink MIMO CDMA signal, the receiving unit performs a simplified process of linear equalization that eliminates the need for inverting the correlation matrix. The correlation matrix is approximated to a good degree by a circulation matrix that is diagonalized by FFT operations, thus substituting two FFTs and one IFFT having a complexity of $O\left({L_F\left(N\mathrm{Delta}\right)}^3+\frac{{\left(N\mathrm{Delta}\right)}^2+2\left(N\mathrm{Delta}\right)}{2}L_F{\log }_2L_F\right)$ for the direct matrix inversion having a complexity of O(L_F³).