Maintaining connectivity in mobile adhoc networks using distributed optimisation

Placement of relay nodes in a wireless sensor network has been considered throughout the literature. The problem becomes more complex when we consider placing additional nodes into a mobile adhoc network. The mobility of the network requires that relay placement be changed constantly in order to maintain network connectivity, and the calculation of relay co-ordinates must take place using partial (non-global) information due to scalability issues. This paper introduces the concept of performing distributed MANET relay placement within nodes´ n-hop neighbourhoods. Networked Autonomous Vehicles (NAVs) act as mobile relays placing themselves at chosen locations. Various algorithms to maintain connectivity are suggested and compared, the most efficient being a bridge and articulation point detection (BAP) algorithm. It is shown that the combined use of up to five additional relay nodes and this algorithm can increase the average ground unit network connectivity by up to 82% and the size of the network´s largest segment by up to 54% in mobile adhoc networks of 10 to 25 nodes.