  This paper presents outerbounds for the two-user Gaussian fading broadcast
channel. These outerbounds are based on Costa's entropy power inequality
(Costa-EPI) and are formulated mathematically as a feasibility problem. For
classes of the two-user Gaussian fading broadcast channel where the outerbound
is found to have a feasible solution, we find conditions under which a suitable
inner and outer bound meet. For all such cases, this paper provides a partial
characterization of the capacity region of the Gaussian two-user fading
broadcast channel.
