Abstract

Upper and lower bounds are derived on the capacity of the free-space
optical intensity channel. This channel has a nonnegative input
(representing the transmitted optical intensity), which is corrupted
by additive white Gaussian noise. To preserve the battery and for
safety reasons, the input is constrained in both its average and its
peak power. For a fixed ratio of the allowed average power to the
allowed peak power, the difference between the upper and the lower
bound tends to zero as the average power tends to infinity and their
ratio tends to one as the average power tends to zero.

When only an average power constraint is imposed on the input, the
difference between the bounds tends to zero as the allowed average
power tends to infinity, and their ratio tends to a constant as the
allowed average power tends to zero.


Keywords

Channel capacity, direct detection, Gaussian noise, infrared
communication, optical communication, pulse amplitude modulation
(PAM).



-||-   _|_ _|_     /    __|__   Stefan M. Moser
[-]     --__|__   /__\    /__   Senior Researcher & Lecturer, ETH Zurich, Switzerland
_|_     -- --|-    _     /  /   Adj. Professor, National Chiao Tung University (NCTU), Taiwan
/ \     []  \|    |_|   / \/    Web: http://moser-isi.ethz.ch/


Last modified: Wed Nov 4 10:49:06 UTC+8 2009