Asymptotic spectral efficiency of MIMO multiple-access systems with arbitrary inputs

While the capacity of a single-user, point-to-point, MIMO channel has been well known, the achievable capacity of MEMO channels in the presence of other co-channel users is much less understood. One such important scenario is the multiple-access (MA) system where communication occurs from many uncoordinated mobile users to a common base station receiver (i.e., multipoint-to-point link). This paper derives a general closed-form expression for the asymptotic (in the sense of large-system limit) spectral efficiency of a MIMO-MA system where the transmitters and the receiver may have different spatial correlations, and the users´ inputs are not necessarily Gaussian. Our analytic formulae are important in that they reveal the spectral efficiency one´s system can achieve given the spatial correlation structures at the transmitters and the receiver, and the input signal distributions. For the special cases that users are homogeneous or users have Gaussian inputs, our results degenerate to previously published results.