@conference {Oualhaj2015987, title = {A coalitional-game-based incentive mechanism for content caching in heterogeneous Delay Tolerant Networks}, booktitle = {IWCMC 2015 - 11th International Wireless Communications and Mobile Computing Conference}, year = {2015}, note = {cited By 1}, pages = {987-992}, abstract = {In recent years, Delay Tolerant Networks (DTNs) have successfully presented as a possible extension of the Internet architecture in order to provide communication support to existing networks. However, these networks have a major issue which is the coordination among relays. In this work, we study the cooperative transmission for DTNs using coalitional game theory. We design a new incentive mechanism for heterogeneous system to induce coordination among DTN relays. In particular, we focus on the source packet dissemination to a destination using tow-hop relaying scheme, considering networks resource constraints: the relay buffer, the packet life time, and the energy consumption according to the mobile technologies. Rational mobiles are organized into separate coalition structures to meet a trade off between the source reward and the energy conservation. We discus the Nash equilibria for our game and the stable strategy state in which no mobile can get a higher payoff through changing unilaterally its coalition. Then, we use the distributed imitative Boltzmann-Gibbs learning algorithm enabling relays to learn the Nash equilibrium strategy; grand coalition. The improvement of the global system performance is examined, and a comparison between different inter-node collaboration states is presented. {\textcopyright} 2015 IEEE.}, doi = {10.1109/IWCMC.2015.7289217}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84949490492\&doi=10.1109\%2fIWCMC.2015.7289217\&partnerID=40\&md5=743073fbd086e6b2dc5623cb07de9531}, author = {Oualhaj, O.A.a and Kobbane, A.a b and Elmachkour, M.a and Sabir, E.c and Ben-Othman, J.b} } @article {Elmachkour20151316, title = {Data traffic-based analysis of delay and energy consumption in cognitive radio networks with and without resource reservation}, journal = {International Journal of Communication Systems}, volume = {28}, number = {7}, year = {2015}, note = {cited By 6}, pages = {1316-1328}, abstract = {A new opportunistic cross-layer MAC protocol involving channel allocation and packet scheduling for cognitive radio networks is proposed. Cognitive radio allows secondary users (SUs) to exploit the available portions of the licensed spectrum bands without interfering with primary users. In particular, we consider a cognitive radio system, where SUs are equipped with two transceivers: a control transceiver and a software-defined radio transceiver. Data traffic characteristics of SUs are considered to ameliorate system performance. So, we propose a mechanism of resource reservation to improve QoS requirements that favors successful SUs to transmit data during x time slots without interfering with primary users. The key novelty of this paper is giving priority for SUs with important data traffic and which frequently solicits data channels to transmit for the remaining time of the ongoing time slot and for the next time slots directly after checking the channel availability. We develop a new analytical model to evaluate delay parameter for two scenarios with and without resource reservation and we then investigate the impact of those scenarios on the energy consumption. We show through simulations that cognitive radio performances increase noticeably with the proposed scheme. Copyright {\textcopyright} 2014 John Wiley \& Sons, Ltd.}, doi = {10.1002/dac.2764}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84925355761\&doi=10.1002\%2fdac.2764\&partnerID=40\&md5=ecf737b718373c4b7731373c0afd1200}, author = {Elmachkour, M.a and Kobbane, A.a c and Sabir, E.b and Ben-Othman, J.c and El Koutbi, M.a} } @conference {Elmachkour20145372, title = {Green opportunistic access for cognitive radio networks: A minority game approach}, booktitle = {2014 IEEE International Conference on Communications, ICC 2014}, year = {2014}, note = {cited By 6}, pages = {5372-5377}, abstract = {We investigate energy conservation and system performance of decentralized resource allocation scheme in cognitive radio networks thoroughly based on secondary users competitive behavior. Indeed, the contention on data channel unoccupied by licensed user leads to a single winner, but also involves a loss of energy of all nodes. In this paper, we apply minority game (MG) to the most important phase from the opportunistic spectrum access (OSA) process: the sensing phase. We attempt to carry out a cooperation in a non-cooperative environment with no information exchange. We study the Nash equilibrium solution for pure and fully mixed strategies, and we use distributed learning algorithms enabling cognitive users to learn the Nash equilibrium. Finally, we provide numerical results to validate the proposed approach. The resource allocation based on minority game approach improves secondary users battery life and the performance of the network. {\textcopyright} 2014 IEEE.}, doi = {10.1109/ICC.2014.6884175}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84907000432\&doi=10.1109\%2fICC.2014.6884175\&partnerID=40\&md5=13fd149d57c8c1d76ace2aecdcd1d08a}, author = {Elmachkour, M.a and Daha, I.b and Sabir, E.c and Kobbane, A.a d and Ben-Othman, J.d} } @article {Elmachkour2014150, title = {The greening of spectrum sensing: A minority game-based mechanism design}, journal = {IEEE Communications Magazine}, volume = {52}, number = {12}, year = {2014}, note = {cited By 5}, pages = {150-156}, abstract = {Cognitive radio technology allows the reuse of the underutilized frequency spectrum on an opportunistic and non-interfering basis by means of introducing, besides the legitimate primary users of the spectrum, a new kind of users called cognitive or secondary users. Thus, reliable spectrum sensing is critical to dynamically detect available licensed frequency bands and mitigate the primary signals, but it remains realistically difficult to carry out. In fact, although distributed collaborative sensing has turned out to be fruitful for the cognitive radio environment, its accuracy is often affected by the selfish and autonomous behavior of users. In this article, we model distributed spectrum sensing and channel allocation as a non-cooperative game, and apply the minority game to bring forth and study the cooperative behavior of users. The novelty brought by our study consists of alleviating the number of users contending for primary channels by giving them the opportunity to choose between the two, either sensing the channel or being inactive during the time slot. To address the trade-off faced by the SUs, we evaluate the performance of two secondary systems in a green communications context: energy consumption and transmission delay. {\textcopyright} 2014 IEEE.}, doi = {10.1109/MCOM.2014.6979967}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84919712749\&doi=10.1109\%2fMCOM.2014.6979967\&partnerID=40\&md5=72e3daa3f2e577d4633668e3bd67f25a}, author = {Elmachkour, M.a and Sabir, E.b and Kobbane, A.a and Ben-Othman, J.c and El Koutbi, M.a} } @conference {Routaib2014, title = {Modeling and evaluating a cloudlet-based architecture for Mobile Cloud Computing}, booktitle = {2014 9th International Conference on Intelligent Systems: Theories and Applications, SITA 2014}, year = {2014}, note = {cited By 0}, abstract = {With the rising popularity of Internet-enabled mobile devices, users are increasingly demanding better quality of service (QoS). However, the resources of these devices and their connectivity levels remain insufficient, even though they are improving, for offering acceptable levels of QoS to users. Cloud computing infrastructures offer large and scalable resources that allow shifting the physical location of computation and storage to the cloud. Nevertheless, the integration of mobile computing with cloud computing would not guarantee adequate levels of service for mobile users. It rather delivers scalability at the cost of higher delay and higher power consumption on the mobile device. Instead, using local resources based on users geographical locations has the potential to improve the performance and QoS for mobile users. In this paper, we present and study a centralized architecture that relies on the concept of local clouds, cloudlets, to leverage the geographical proximity of resources to mobile users and offer them a better user experience. We use a continuous time Markov-chain (CTMC) to model the different nodes of the architecture: user nodes, cloudlets, and the main cloud. We estimate the delay incurred in the proposed architecture by simulating search engine queries generated by mobile users using the CTMC state models. Initial simulation results show that the usage of a cloudlet-based architecture especially centralized architecture has an efficient gains in terms of latency delay and synchronisation mechanisms. {\textcopyright} 2014 IEEE.}, doi = {10.1109/SITA.2014.6847290}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84904645627\&doi=10.1109\%2fSITA.2014.6847290\&partnerID=40\&md5=54ed4186648b2b2f3a5de1747850ad4d}, author = {Routaib, H.a and Badidi, E.b and Elmachkour, M.a and Sabir, E.c and Elkoutbi, M.a} }