  This paper presents a new approach to distributed controller design that
exploits a partial-structure representation of linear time invariant systems to
characterize the structure of a system. This partial-structure representation,
called the dynamical structure function, characterizes the {\em signal
structure}, or open-loop causal dependencies among manifest variables,
capturing a significantly richer notion of structure than the sparsity pattern
of the transfer function. The design technique sequentially constructs each
link in an arbitrary controller signal structure, and the main result proves
that the resulting controller is either stabilizing or no controller with the
desired structure can stabilize the system.
