Increasing network lifetime by reducing energy consumption across the network is one of the major concerns while designing routing protocols for Mobile Ad-Hoc Networks. In this paper, we investigate the main reasons that lead to energy depletion and we introduce appropriate routing metrics in the routing decision scheme to mitigate their effect and increase the network lifetime. For our routing scheme, we take into consideration multiple layer parameters, such as MAC queue utilization, node degree and residual energy. We integrate our multi-metric routing scheme into OLSR, a standard MANET proactive routing protocol. We evaluate via simulations in NS3 the protocol modifications under a range of different static and mobile scenarios. The main observations are that in static and low mobility scenarios our modified routing protocol leads to a significant increase (5 -20 ) in network lifetime compared to standard OLSR and slightly better performance in terms of Packet Delivery Ratio (PDR).
Multiple metrics routing schemes, which are more related to our work, have also been proposed. An adaptive multiple metrics routing scheme for AODV is introduced in @cite_7 . The authors take into account three routing metrics, which are hop count, traffic load and energy cost, and combine them to evaluate the cost of the paths. In addition, a predictive multiple metrics routing scheme for proactive protocols, like OLSR, is presented in @cite_12 . The chosen routing metrics are mean queueing delay, energy cost and residual link lifetime. The authors designed a multi-objective routing schemes that evaluates the multiple metrics in a composite way and achieves better performance in terms of Packet Delivery Ratio (PDR) and network lifetime.
@cite_12 @cite_7
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In this paper we present a MANET proactive routing enhancement scheme by comprehensive evaluation of multiple dynamic routing metrics, including delay, energy cost, and link stability. We developed efficient routing metric prediction methods: predicting delay and energy using double exponential smoothing, and predicting link stability using a heuristic based on the normal-like distributions of the link lifetimes in typical MANET mobility scenarios. The routing metrics predictions are incorporated with regular routing information exchanges. On each node, routing table is constructed by a modified version of Dijkstra's algorithm, which evaluates the predicted metrics values compositively. We integrated such a multi-metric prediction evaluation mechanism into OLSR and name it OLSR MC. We show by simulation that OLSR MC is more adaptive to the network dynamics and therefore is able to improve performance significantly on multiple routing objectives, including higher packet delivery ratio, shorter average end-to- end delay, and prolonged network energy lifetime. The calculation of path cost is a critical component of route discovery for network routing. The criteria used to represent path cost guides resource consumption in the network. In this paper, we describe our approach, a set of protocols based on our Multiple Metrics Routing Protocol (MMRP) for integrating hop count, energy consumption, and traffic load into the path cost calculation for ad hoc or multihop-cellular networks. Our initial aim is to select among multiple disjoint routes in order to maintain a low path cost, in terms of energy consumption and delay, without depleting resources at popular intermediate nodes. One extension of MMRP removes the constraint that only disjoint paths are considered and enables discovery of more optimal routes. A second extension includes adaptive adjustment of cost metrics to support device classification (e.g., energy capacity, bandwidth) in heterogeneous networks. We illustrate our approach with a simple example, followed by extensive simulation analysis. Results indicate that proper combination of multiple metrics for calculating path costs results in improved performance and lower overall system resource consumption as compared to AODV or energy efficient routing protocols.