High-SNR Capacity Analysis of mmWave Systems under Finite-Dimensional Channel Model

This paper investigates the high signal-to-noise ratio (SNR) ergodic capacity of point-to-point millimeter wave systems under finite-dimensional channel model. We first derive a closed-form expression for the high-SNR ergodic channel capacity under arbitrary antenna configurations and arbitrary number of paths when the transmitter and receiver spatial correlation matrices are non-singular. Then, novel closed-form tight upper bounds and approximations for the high-SNR ergodic capacity are obtained by means of Jensen’s inequality and order statistics. The results show that the high-SNR ergodic capacity increases logarithmically with the eigenvalues of spatial correlation matrices and the transmit SNR per antenna. Moreover, it is interesting that the upper bounds and approximations derived from the combination of Jensen’s inequality and order statistics exhibit better performance than the other with only Jensen’s inequality. Monte-Carlo simulations are performed to validate our analytical results.