On the energy efficiency of low-mobility subsystems in hierarchical ad hoc networks

Hierarchical topologies have been suggested to increase network stability in mobile ad hoc networks (MANETs). In a hierarchical ad hoc network nodes are clustered in more stable virtual groups. Ideally, the members of these groups can establish links with longer lifetimes with the leader of the group, clusterhead. However, in highly mobile ad hoc networks, hierarchical topologies face the problem of continuous reorganization. The overhead required to maintain the hierarchical topology is increased and average link lifetime is greatly reduced, producing an increase in the packet loss rate. This two-fold effect lowers the energy efficiency of the system. In this framework, this paper explores the effectiveness of the division of a highly mobile network in smaller and low mobile subsystems where clustering operations can form and maintain more stable hierarchies. We analytically prove that the division of a high mobility ad hoc network in different mobility patterns can produce low mobility subsystems that foster clustering stability. The impact of the increased stability on the energy efficiency is then evaluated by simulations.