Optimal Orthogonal Carriers and Sum-SINR/Sum-Capacity of the Multiple-Access Vector Channel

For the general correlated multiple-access vector channel, we derive algebraically the sum-SINR (signal-to-interference-plus-noise ratio) optimal orthonormal set of carriers for any given set of carrier amplitudes. If, in addition, the correlated multiple-access channel is assumed Gaussian, the sum-capacity optimal orthonormal carrier set design and the jointly sum-capacity optimal orthonormal carrier and power assignment, for a given power budget, follow readily.