Energy optimization for proactive unicast route maintenance in MANETs under end-to-end reliability requirements

Many time-critical applications for Mobile Ad hoc NETworks (MANETs), such as the military applications and disaster response, call for proactive link and route maintenance to ensure low latency for reliable data delivery. The goal of this paper is to minimize the energy overhead due to the high control traffic caused by the periodic route and link maintenance operations in the proactive routing protocols for MANETs. This paper — (i) categorizes the proactive protocols based on the maintenance operations performed; (ii) derives analytical estimates of the optimum route and link update periods for the different protocol classes by considering (a) the data traffic intensity, (b) link dynamics, (c) target reliability, measured in terms of Packet Delivery Ratio (PDR), and (d) the network size; and (iii) proposes a network layer dynamic Optimization of Periodic Timers (OPT) method based on the analytical estimates to locally vary the update periods in the distributed nodes. Simulation results show that DSDV-Opt, a variation of DSDV protocol using OPT, — (i) achieves the target PDR with 98.7% accuracy while minimizing the overhead energy; (ii) improves the protocol scalability; and (iii) reduces the control traffic for low data traffic intensity.