Bit-Per-Joule Performance of Power Saving Ad Hoc Networks under Mobile Backbone Coverage

Energy efficient MAC protocols have been developed for wireless sensor and ad hoc networks so that inactive nodes can transition to sleep state to conserve energy. It has been recognized that forming and keeping a continuously awake Connected Dominating Set (CDS) serves to significantly reduce the route setup latency (since it minimizes the number of wakeup operations that are undertaken). Recently published studies show that, under certain traffic conditions, the CDS approach can lead to the reduction of the average level of energy consumption while ensuring a high network throughput level. Under the Mobile Backbone Network (MBN) architecture introduced by I. Rubin et al., a mobile backbone is dynamically constructed to provide a topological covering of the network. Nodes that join the mobile backbone are identified as Backbone Nodes (BNs). In this paper, we study a MBN Power Saving (MBN-PS) system. The dynamically elected BNs are kept active and are used to effectively manage the awake and sleep states of their client nodes. We study the throughput (per-watt) efficiency performance of the MBN-PS protocol by analytical calculations, as well as by extensive simulation evaluations. We analytically show that when the number of active network flows is above a minimal level, the underlying throughput efficiency attained by the MBN-PS scheme is better than that achieved by a corresponding network that does not form a backbone structure.