Some simple groups which are determined by the set of their character degrees I

The following conjecture is studied. Let $G$ be a simple nonabelian group. If $H$ is any group which has the same set of character degrees as $G$, then $H \cong G \times A$, where $A$ is abelian. In the present paper this is proved if $G$ is a Suzuki group on some $SL(2,2^{f})$.