  This paper studies regulated state synchronization of discrete-time
homogeneous networks of non-introspective agents in presence of unknown
non-uniform input delays. A scale free protocol is designed based on additional
information exchange, which does not need any knowledge of the directed network
topology and the spectrum of the associated Laplacian matrix. The proposed
protocol is scalable and achieves state synchronization for any arbitrary
number of agents. Meanwhile, an upper bound for the input delay tolerance is
obtained, which explicitly depends on the agent dynamics.
