                                       ! " ! " ! " ! "  ## $   ## $   ## $   ## $ Saloua CHETTIBI 1 and Salim CHIKHI 2 1,2 MISC Laboratory, University of Constantine 2 Constantine, 25000 Algeria Abstract Optimized Link State Routing (OLSR) is a standard proactive routing protocol for Mobile Ad-hoc NETworks (MANETs). In this paper, we use a zero-order Sugeno Fuzzy Logic System (FLS) for adjusting the willingness parameter in OLSR protocol. Decisions made at each mobile node by the FLS take into account its remaining energy and its expected residual lifetime. Simulation study revealed that the proposed protocol Fuzzy Energy-Aware OLSR (FEA-OLSR) is more energy efficient than EE-OLSR a heuristic based energy-aware variant of OLSR. Keywords: OLSR, MANETs, Zero Order Sugeno Fuzzy System, Willingness Parameter, Energy-Aware Routing. 1. Introduction Mobile Ad-hoc NETwork (MANET) is a collection of mobile wireless devices that are able to communicate without any pre-established network infrastructure. To ensure routing service, all nodes in MANET cooperate in forwarding neighbors traffic until reaching its intended destination. Traditional routing protocols built for wired networks could not be directly used in MANETs. This is because MANETs are characterized by many challenging features including poor wireless-links quality, nodes mobility, limited bandwidth and energy-resources. This is in addition to the lack of any central control. Due to the above-mentioned features, the design of specific routing solutions for MANETs has made the main focus of almost all researchers’ contributions in the field of mobile ad hoc networking [1]. Routing protocols for MANETs could be classified as either reactive or proactive [2]. A reactive routing protocol does not calculate routes beforehand, but only when data traffic is present for routing. This is done via a route discovery procedure which is initiated by the source node. This latter broadcasts a Route REQuest (RREQ) packet to all its one-hop neighbors. Each neighboring node rebroadcasts again the received RREQ. The same operation is repeated until that destination node is reached. In answer, the destination node generates a Route REPlay (RREP) packet. This approach presents the disadvantage of a long response time in comparison to its proactive counterpart. Proactive routing protocols, also known as table driven, are modifications of traditional link-state and distance- vector based routing protocols for wired networks. They are built on periodic exchange of routing information. This is in the aim of making routing tables up to date all the time. Moreover, routes are maintained toward all possible destinations. Hence, routing could start immediately whenever data traffic is present. However, the main drawback of proactive routing is the great amount of generated routing overhead. This leads to the wastage of network-bandwidth and nodes-energy. One interesting proposals to reduce the generated routing overhead by the proactive approach is the concept of Multi-Point Relays (MPRs) introduced in the OLSR protocol [3]. The key idea is to limit the number of retransmissions required for a node to flood a packet in the entire network. For this purpose, each node elects a subset of its one-hop neighbors to be responsible of forwarding its broadcasted packets. Those nodes are called MPRs. Certainly such a solution also contributes to minimization of the overall network energy consumption. However, as a non-uniform routing protocol, OLSR overuses the energy of the MPRs nodes. In fact, energy is drained more quickly in MPRs nodes than in no-MPRs ones. Therefore, it is a mandatory to rethink energy aware versions for the OLSR protocol. Particularly, maximum lifetime routing approach that avoids nodes with poor energy profiles should be adopted. In this paper, we propose an energy-aware OLSR variant built on a zero order Sugeno fuzzy logic system. To the best of our knowledge, this work is the first one in the literature to use a FLS for adjusting the willingness parameter in OLSR protocol according to nodes energy profiles. The reminder of this paper is organized as follows. Section 2 reviews the related literature to maximum IJCSI International Journal of Computer Science Issues, Vol. 10, Issue 2, No 1, March 2013 ISSN (Print): 1694-0814 | ISSN (Online): 1694-0784 www.IJCSI.org 136 Copyright (c) 2013 International Journal of Computer Science Issues. All Rights Reserved.