Reputation-Based Cooperative Detection Model of Selfish Nodes in Cluster-Based QoS-OLSR Protocol

The QOLSR is a multimedia protocol that was designed on top of the optimized link state routing (OLSR) protocol for mobile ad hoc network. It considers the quality of service (QoS) of the nodes during the selection of the multi-point relay (MPRs) nodes. One of the drawbacks of this protocol is the presence of selfish nodes that degrade the network lifetime. The limited energy and resources, and the absence of any motivation mechanism cause mobile nodes to behave selfishly during the MPRs selection. A new MPR selection based on cluster head election was proposed in previous work to increase network lifetime. In this paper, we consider the selfishness during the election and selection process by proposing the use of reputation system that will motivate nodes to participate during the selection of MPRs, where the reputation is calculated based on VCG mechanism design. After solving the selfishness during network formation, we have discovered that nodes can misbehave after being selected/elected. Such a passive malicious behavior could lead to a denial of service attack due to the drop of packets. As a solution, we propose a hierarchal cooperative watchdog detection model for the cluster-based QOLSR, where nodes cooperate in a hierarchical manner to detect selfish nodes. Moreover, to motivate watchdogs to monitor and cooperate with each other, incentives are given and calculated using cooperative game theory, where Shapley value is used to compute the contribution of each watchdog on the final decision. Simulation results show that the novel cluster-based QoS-OLSR model can give incentive to nodes to behave normally without sacrificing the quality of service of the network. In addition, the hierarchical cooperative detection model shows a more reliable and efficient detection of selfish nodes.