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Doctorate thesis defense of Ghayet El Mouna ZHIOUA

Doctorate thesis defense on Friday May 30th, 2014 at 9h00, Amphi Iset'Com at Sup'Com

Entitled : Cooperation VANET – 4G Cellular Infrastructure : Quality of Service and Performances

Presented by : Ghayet El Mouna ZHIOUA 



Noureddine BOUDRIGA

Professor, Sup'Com - Tunisia






Professor, University of California Los Angeles (UCLA) - USA



Professor, ENSI - Tunisia


André-Luc BEYLOT

Professor, INP-ENSEEIHT, Toulouse - France


Thesis Directors


Associate Professor, Sup'Com - Tunisia



Associate Professor, TELECOM ParisTech - France



Professor, Sup'Com - Tunisia



Gérard MEMMI

Head of Networks and Computer Science Department, TELECOM ParisTech, France


LTE-Advanced standard is a well-designed system that meets the requirements of 4G cellular networks. It might be widely adopted by numerous operators as the next generation of their cellular networks. On the other side, vehicular ad hoc networks (VANETs) have been widespread due to their relevant attractive features such as the self-organization and the decentralized administration. In our work, we investigate upon the cooperation between vehicular ad hoc networks and the cellular infrastructure. Thanks to this cooperation, reliable links could be guaranteed ensuring the quality of service of vehicular applications. The main critical issue that has to be addressed to achieve a proper cooperation is gateway selection where the gateway will play the interconnection role between both systems. We propose an original VANET-LTE-Advanced multi-criteria and QoS related approach, named FQGwS algorithm, that selects the appropriate gateway for a given source vehicle under the scope of V2I communications. It is a fuzzy QoS-balancing gateway selection algorithm where the decision over the gateway depends on the traffic QoS class, vehicles velocity, load and infrastructure features. Complexity analysis of FQGwS algorithm shows that it presents a linear complexity. A gateway selection algorithm is also proposed for I2V communications, named GIV, for clustered and non-clustered VANETs. GIV considers the I2V link connectivity duration, link quality, and data flow volume. The cooperation between the vehicular ad hoc network and the cellular infrastructure is also a very promising solution for cellular traffic overload. This presents an interesting solution for the ever increasing traffic demand. Thus, in the second part of our work, we studied the potential of using VANETs for offloading the 4G LTE-Advanced cellular infrastructure. We defined mechanisms based on analytical studies discussing the capacity of VANETs to route a fraction of cellular traffic while considering constraints related to the path availability, data flows volume, and gateways' capacity. We first presented the VOPP offloading problem formulation based on constraints related to the channel occupation duration to transmit the flow and to the channel contention. We defined after the e-VOPP model based on VOPP to compute the maximum traffic volume that could be offloaded through the I2V link. Afterward, we integrate the QoS consideration, respectively V2V interferences and channel aggregation in the offloading problem formulation, in eQ-VOPP, respectively FOSAA. With FOSAA model, we jointly perform data flow selection and contention resolution. More precisely, FOSAA formulation considers I2V/V2V interferences and links' quality, data flows volume, gateways' capacity, channel saturation limit, nodes' active time and aggregation to quantify the VANET capacity to support cellular traffic. The evaluation results show that FOSAA converges and presents high offloading fraction by prioritizing the offloading of one and two hops flows.


VANET, LTE-Advanced, I2V/V2I Communications, Gateway Selection, Fuzzy Logic, Multihop, Quality of Service, Offloading, Max Flow Optimization, Contention, Active time, Interferences.