  This paper deals with the H2 suboptimal output synchronization problem for
heterogeneous linear multi-agent systems. Given a multi-agent system with
possibly distinct agents and an associated H2 cost functional, the aim is to
design output feedback based protocols that guarantee the associated cost to be
smaller than a given upper bound while the controlled network achieves output
synchronization. A design method is provided to compute such protocols. For
each agent, the computation of its two local control gains involves two Riccati
inequalities, each of dimension equal to the state space dimension of the
agent. A simulation example is provided to illustrate the performance of the
proposed protocols.
