*1.1. Communication Issues*

*Mobile Ad-hoc NETworks (MANETs*) constitute a particular example of scenarios where the topology of the robot network varies dynamically over time. This kind of network is recommended when the fixed infrastructure is no longer available, e.g., in disasters to support the communication among rescue team members. In such cases, connectivity is of utmost importance because the loss of communication could imply human losses.

A first critical issue concerns the collective knowledge of the environment. Under communication restrictions, such knowledge cannot be assumed to be always accessible and depending on the coordination mechanism could be the cause of significant performance degradation [20]. Therefore, depending on the application, the exploration strategy should take this into account in order to prevent the robots from becoming completely unconnected, let say isolation situations. Such an isolation situation, as well as its possible effects, are illustrated in the example scene depicted in Figure 1.

**Figure 1.** Re-exploration caused by restricted communication. [20]. The yellow portion of the map is only known by robot B. Thus, robot A goes to re-explore the region beyond the red frontier.
