CARE: Coverage-Aware Connectivity Restoration Algorithm for Mobile Actor/Robot Networks

Maintaining coverage-aware connectivity is extremely crucial for successful operation of mobile actor/robot networks as mobile nodes have to collaborate on the data received from sensors and perform coordinated action. However, failure of a critical node (i.e., cut vertex) may introduce a coverage hole besides partitioning the network into disjoint segments, and thus disrupts the operation. Most of the published schemes are reactive, require additional placement of nodes and only concentrate on restoring connectivity. Mission-critical time-sensitive applications crave an instantaneous self-healing recovery with minimum overhead. This paper presents a localized and hybrid coverage-aware connectivity restoration (CARE) algorithm which opts to rejuvenate lost connected coverage while minimizing recovery overhead. The design philosophy of CARE is based on "caretaker" theory. CARE proactively segregates critical/non-critical nodes, designates appropriate caretaker to each critical node in order to minimize recovery delay and avoid overreacting against non-critical node failure. CARE prefers to nominate a highly connected non-critical neighbor with highest overlapped coverage to minimize the repercussions and scope of recovery. The pre-designated guardian detects the failure and instigates a recovery that may involve controlled and coordinated multi-node relocation. Simulation results confirm the effectiveness and efficiency of CARE compared to contemporary schemes found in the literature.