Relays Recovery andMAC-Layer Cooperation Models in VANETs

  • Doaa Al-Terri

Student thesis: Master's Thesis


In this thesis, we address the problem of selfishness in Vehicular ad-hoc Networks (VANETs) at both network and MAC layers. At the network layer, a vehicle is considered selfish when it is over speeding or under speeding the maximum/minimum road speed limits. This leads to a disconnected network due to the non-cooperative behavior in forwarding packets. At the MAC layer, a selfish vehicle can misbehave to acquire more bandwidth by not complying with the standard MAC protocol design. Thus, the presence of selfish nodes would hinder normal nodes' services. In this research, we explore the Qos-OLSR protocol to study the impact of the nodes' misbehavior on a routing protocol. QoS-OLSR is a cluster based proactive routing protocol that takes into account the quality of service while selecting the MultiPoint Relay (MPR) nodes. This protocol does not consider the case of MPR disconnection due to mobility caused by the misbehaving nodes, which leads to network disconnection. Therefore, the performance of QoS-OLSR has been improved by proposing a new routing protocol based on Intelligent Water Drop algorithm identified as IWD-QoS-OLSR protocol. This protocol introduces an MPR recovery algorithm that is capable of selecting alternatives in the case of link failure disconnection, caused by the selfish nodes behavior. The existence of selfish behavior at the MAC layer disrupts the services of the network. The distributed nature of the CSMA/CA MAC protocol allows rational nodes to deliberately manipulate their backoff parameters to gain an unfair share of the network throughput. Therefore, we develop a game theoretical mechanism that encourages the rational nodes to behave normally under the threat of retaliation. Thus, the selfish nodes are motivated to cooperate if they aim to maximize their obtained payoff. Otherwise, all the nodes will end up with less payoffs. Finally, simulations are conducted to evaluate the performance of the proposed models. Indexing Terms: VANETs, QoS-OLSR, IntelligentWater Drop algorithm(IWD), CSMA/CA, Game Theory.
Date of AwardJun 2016
Original languageAmerican English
SupervisorHassan Barada (Supervisor)


  • VANETs
  • QoS-OLSR
  • Intelligent Water Drop algorithm(IWD)
  • Game Theory.

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