  Decentralized planning for multi-agent systems, such as fleets of robots in a
search-and-rescue operation, is often constrained by limitations on how agents
can communicate with each other. One such limitation is the case when agents
can communicate with each other only when they are in line-of-sight (LOS).
Developing decentralized planning methods that guarantee safety is difficult in
this case, as agents that are occluded from each other might not be able to
communicate until it's too late to avoid a safety violation. In this paper, we
develop a decentralized planning method that explicitly avoids situations where
lack of visibility of other agents would lead to an unsafe situation. Building
on top of an existing Rapidly-exploring Random Tree (RRT)-based approach, our
method guarantees safety at each iteration. Simulation studies show the
effectiveness of our method and compare the degradation in performance with
respect to a clairvoyant decentralized planning algorithm where agents can
communicate despite not being in LOS of each other.
