Abstract

Stationarity is investigated in the context of a general
multiple-input–multiple-output (MIMO) fading channel with memory.
It is shown that stationary processes behave nicely as one does
expect.

Concretely, this reports concentrates on three topics with regard to
stationarity: firstly it is proven that—under weak conditions on
the channel—any stationary channel model will have a
capacity-achieving input distribution that is stationary. This
statement holds in general and is not restricted to MIMO fading
channels.

Secondly, it is shown that entropy rate is well-defined also
in the context of differential entropy and stationary processes.
Moreover, it can be generalized to more complex forms of conditional
entropy rates without problems as long as all involved processes are
stationary. Again, this are general statements not specific to MIMO
fading.

Thirdly, in the context of MIMO fading it is shown that the memory
of a stationary process fades in a way that one expects.

Keywords

Channel capacity, fading number, flat fading, stationarity.

-||-   _|_ _|_     /    __|__   Stefan M. Moser
[-]     --__|__   /__\    /__   Senior Scientist, ETH Zurich, Switzerland
_|_     -- --|-    _     /  /   Adjunct Professor, National Yang Ming Chiao Tung University, Taiwan
/ \     []  \|    |_|   / \/    Web: https://moser-isi.ethz.ch/

Last modified: Fri Jun 20 09:00:37 UTC+8 2008