On the asymptotic spectral efficiency of uplink MIMO-CDMA systems over rayleigh fading channels with arbitrary spatial correlation

In this paper, we study the asymptotic spectral efficiency (ASE) of the uplink multiple-input-multiple-output direct-sequence code-division multiple-access (MIMO-CDMA) systems supporting multiple users, when assuming communications over flat-fading channels with arbitrary correlation in the spatial domain. In the MIMO-CDMA systems considered, the system-channel-related matrix expressed by H is a block random matrix, whose entries may be correlated due to the spatial correlation. In this paper, the theory of operator-valued free probability is employed to derive the approximate asymptotic eigenvalue distribution (AED) of the correlation matrix R_H = H^H H, where the size of the block matrix H tends to infinity. Based on the approximate AED, the spectral efficiency (SE) performance of multiuser MIMO-CDMA systems is studied by both analysis and simulations. Our simulation and numerical results show that the corresponding ASE is, in general, capable of providing very good prediction of the SE achieved by the practical MIMO-CDMA systems.