In this paper, we present an analytical lower bound on the ergodic capacity of optical multiple-input multiple-output (MIMO) channels. It turns out that the optical MIMO channel matrix which couples the mt inputs (modes/cores) into mr outputs (modes/cores) can be modeled as a sub-matrix of a m x m Haar-distributed unitary matrix where m > mt,mr. Using the fact that the probability density of the eigenvalues of a random matrix from unitary ensemble can be expressed in terms of the Christoffel-Darboux kernel. We provide a new analytical expression of the ergodic capacity as function of signal-to-noise ratio (SNR). Moreover, we derive a closed-form lower-bound expression to the ergodic capacity. In addition, we also derive an approximation to the ergodic capacity in low-SNR regimes. Finally, we present numerical results supporting the expressions derived.
@article{arxiv.1701.08836,
title = {New Lower Bound on the Ergodic Capacity of Optical MIMO Channels},
author = {Rémi Bonnefoi and Amor Nafkha},
journal= {arXiv preprint arXiv:1701.08836},
year = {2017}
}
Comments
4 pages, 4 figures, accepted at IEEE ICC 2017 Optical Networks and Systems Symposium