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. This paper presents two novel mechanisms for the OLSR routing protocol, aiming to improve its energy performance in Mobile ah-hoc Networks. Routing protocols over MANET are an important issue and many proposals have been addressed to efficiently manage topology information, to offer network scalability and to prolong network lifetime. However, few papers consider a proactive protocol (like OLSR) to better manage the energy consumption. OLSR presents the advantage of finding a route between two nodes in the network in a very short time, thanks to its proactive scheme, but it can expend a lot of resources selecting the MultiPoint Relays (MPRs) and exchanging Topology Control information. We propose a modification in the MPR selection mechanism of OLSR protocol, based on the Willingness concept, in order to prolong the network lifetime without losses of performance (in terms of throughput, end-to-end delay or overhead). Additionally, we prove that the exclusion of the energy consumption due to the overhearing can extend the lifetime of the nodes without compromising the OLSR functioning at all. A comparison of an Energy-Efficient OLSR (EE-OLSR) and the classical OLSR protocol is performed, testing some different well-known energy aware metrics such as MTPR, CMMBCR and MDR. We notice how EE-OLSR outperforms classical OLSR, and MDR confirms to be the most performing metric to save battery energy in a dense mobile network with high traffic loads. Energy efficiency is a key issue in wireless ad hoc and sensor networks. Several directions have been explored to maximize network lifetime, among them energy efficient routing. In this paper, we show how to extend the standardized OLSR routing protocol, in order to make it energy efficient. To take into account residual node energy, three new selection algorithms of multipoint relays, based on the minimum residual energy are evaluated, the best one is chosen. This OLSR extension selects the path minimizing the energy consumed in the end-to-end transmission of a flow packet and avoids nodes with low residual energy. We compare this extension with a two-path source routing strategy (with different links or different nodes). An extensive performance evaluation shows that this energy efficient extension maximizes both network lifetime and user data delivered. The energy-efficiency usage is relative to each layer of wireless sensor networks. In order to improve the ZigBee mesh routing protocol for energy-efficiency usage, we propose a routing algorithm combining AODVjr with the node residual energy. To reduce the energy consumption of bottleneck nodes and extend network lifetime, the improved routing algorithm aims to build a new balancing method between the energy-aware routing metric and the shortest path. Based on the energy model of CC2430 RF transceiver, the implemented routing protocol is simulated using NS2 (Network Simulator version 2). Simulation result shows that this improved protocol can extend the network lifetime very efficiently.