Asymptotic mutual information of multiple-path Rician fading MIMO multiple-access channel

This paper studies the asymptotic mutual information of a multiple-path Rician fading multiple-input multiple-output (MIMO) multiple-access (MA) channel for any given input distributions (not necessarily Gaussian). The sense of asymptotic behavior we consider is the large-system limit in which the numbers of antennas at the transmitter and receiver go to infinity with constant ratio. Using the replica method, an analytical tool developed in statistical physics, we obtain not only the spectral efficiency formula that assumes optimal joint decoding at the receiver but also the asymptotic spectral efficiency of a more practical system which performs separate detection and decoding (spatial detection followed by a temporal error-correction decoder). The results not only encompass several previously published results as special cases, but also gives for the first time the asymptotic performances of optimal joint decoding and separate decoding with arbitrary input distribution in the general MIMO Rician channels. Through computer simulations, we see that the proposed asymptotic solution gives good estimates for the average mutual information of the channels even with only a few antenna elements at transmitter and receiver.