PROJECT TITLE :

Capacity Bounds and High-SNR Capacity of MIMO Intensity-Modulation Optical Channels - 2018

ABSTRACT:

The capability of the intensity modulation direct detection multiple-input-multiple-output channel is studied. Therein, the nonnegativity constraint of the transmit signal limits the applicability of classical schemes, as well as precoding. So, new ways that are required for deriving capability bounds for this channel. To this end, capability lower bounds are developed in this Project by deriving the achievable rates of two precoding-free schemes: channel inversion and orthogonal-higher triangular matrix product decomposition. The achievable rate of a dc-offset singular-value decomposition-based scheme is additionally derived as a benchmark. Then, capacity higher bounds are derived and compared against the lower bounds. Thence, the capacity at high signal-to-noise ratio (SNR) is characterized for the case where the amount of transmit apertures isn't larger than the quantity of receive apertures, and is shown to be achievable by the QR decomposition scheme. This is shown for a channel with average intensity or peak intensity constraints. Beneath each constraints, the high-SNR capacity is approximated inside a tiny gap. Extensions to a channel with more transmit apertures than receive apertures are mentioned, and capability bounds for this case are derived.