Upper and lower bounds on the capacity of the free-space optical
intensity channel are computed. The lower bounds are found using the
common expression for the capacity and the power entropy inequality,
whereas the upper bounds are mainly found with a recently presented
technique from Lapidoth and Moser using the dual expression for the
capacity. At high power upper and lower bounds are presented which
become asymptotically tight. Also for low power some good upper and
lower bounds for the capacity are found. Most of the results are new
and cannot be compared to previously found expressions for the
capacity. However, where this is possible more general results are
obtained in this report.


Channel capacity, upper and lower bounds, free-space optical intensity
channel, infrared channel.

-||-   _|_ _|_     /    __|__   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 May 10 13:01:03 2006