In this paper, we propose a new approach to federate sim- ulations for cyber-physical systems. A federation is a combination of simulations being able to interact with each other upon a standard of communication. In addition, mixed simulations are defined as several par- allel simulations that are taken place in a common time progress. These simulations run on the models of physical systems, which are built based on cellular automata. The experimental results are performed on a typ- ical federation of three simulations for forest fire spread, river pollution diffusion and wireless sensor network. The obtained results can be used to predict as well as observe the behavior of physical systems in their interactions.