Exact capacity expressions for dual-branch ricean MIMO channels

In this paper we derive exact expressions for the mutual information (MI) probability density function and the MI cumulative distribution function of dual-branch multipleinput multiple-output (MIMO) systems (either two transmit (Tx) or two receive (Rx) antennas) communicating over a Ricean channel with no constraint on the rank of the line-of-sight (LOS) channel matrix. This is done both for the case where the channel is only known at the Rx, and for the case where the channel is known both at the Tx and the Rx. As an example, to evaluate the expressions, we employ uniform linear arrays and give expressions for the eigenvalues of the LOS channel matrix for the dual-branch case.