Time filter

Source Type

Tunis, Tunisia

Zangar N.,MEDIATRON Laboratory | Abdennebi M.,Paris-Sorbonne University
2016 13th IEEE Annual Consumer Communications and Networking Conference, CCNC 2016 | Year: 2016

One of the promising technologies which is being regarded in the future 5G standard long Term Evolution (LTE) Release 13 is Machine-to-Machine or M2M communications. It represents a key component of Internet of Things (IoT) and smart spaces. One of the most difficult challenges to support M2M communications is their huge number compared to available radio resources. Hence, to deal with random access channel (RACH) overload and to better control the access in LTE-A Networks, the 3GPP proposed the Access Class Barring (ACB) factor concept. In this paper, we proposed an algorithm to improve this method based on adaptive multiple ACB factors, according to M2M traffic category with respect to their access delay budget and drop rate (QoS parameters). Simulations were done for testing the effectiveness of our MACB scheme and show that using multiples ACB factors and dynamically adjusting them to the congestion level in addition to traffic type category increases the access probability and reduces overload. The obtained results were then compared to the basic ACB method and show that the access probability increases especially for high priority traffic. © 2016 IEEE. Source

Kammoun I.,LETI Laboratory ENIS | Siala M.,MEDIATRON Laboratory
European Transactions on Telecommunications | Year: 2011

In this paper, we investigate fast time-varying channel estimation for two orthogonal space-time block-coded systems with either two or three transmit antennas and with one receive antenna. We propose an iterative expectation-maximisation-based maximum a posteriori (MAP) semi-blind algorithm for the estimation of the discrete propagation channels seen from the transmit antennas. This algorithm requires a convenient representation of the channel using a discrete version of the Karhunen-Loève expansion theorem. It incorporates the coded structure of each block in a turbo-processing fashion and uses the MAP training-based channel estimation algorithm for its optimum initialisation. The transmit antennas are assumed to be spatially correlated for the system with two transmit antennas and spatially uncorrelated for the three-antenna system. The validity of the proposed algorithm is highlighted by simulation results. The performance of the proposed receivers, based on MAP channel estimation, for the two systems approaches that of the perfect channel state information receiver, even for very time selective fading channels. Copyright © 2011 John Wiley & Sons, Ltd. Source

Ben Rejeb S.,MEDIATRON Laboratory | Nasser N.,Alfaisal University | Tabbane S.,MEDIATRON Laboratory
2015 IEEE Wireless Communications and Networking Conference, WCNC 2015 | Year: 2015

Among the major challenges in 3GPP LTE-A (3rd Generation Partnership Project Long Term Evaluation) and beyond networks are the convergence of services towards IP technology, the quality of service (QoS) and the maintenance of multimedia flows transmitted on wireless networking for mobile and heterogeneous users. In this environment, multimedia services must face various disadvantages generated by the unreliability of the wireless channel shared by several users. These new characteristics impose new requirements when designing wireless protocol, such as in LTE-A networks, where protocols must be dynamically adapted with the continuous changes of the radio operator state channel and seek at the same time to meet the QoS requirements with the supported applications. In this context, we will propose a new cross layer and performances optimization of the 3GPP LTE-A system. Our major contribution consists to set up coordinated interactions between high layers applications representing for example video streaming and those of low layers, such as network, MAC (Medium Access Control) and physical layer. The information exchange between these layers will lead to optimize the application operation according to the changes observed on the radio operator channel. Thus, this solution would reduce the probabilities of the application dysfunction or interruption, while respecting the QoS constraints (time, throughput, PLR (Packet Loss Ratio) and maintain a constant flow for the user. © 2015 IEEE. Source

Abderrahim W.,MEDIATRON Laboratory | Choukair Z.,MEDIATRON Laboratory
Proceedings - 2015 IEEE 17th International Conference on High Performance Computing and Communications, 2015 IEEE 7th International Symposium on Cyberspace Safety and Security and 2015 IEEE 12th International Conference on Embedded Software and Systems, HPCC-CSS-ICESS 2015 | Year: 2015

Cloud computing is widely adopted thanks to the high business agility it guarantees to its consumers. Cloud services negotiation in the market place is a crucial task for both cloud consumer and cloud provider mainly if the cloud consumer inquires specific properties for its applications. Therefore, this task is delegated to a third part which is the cloud broker. This latter is responsible for delivering services to the cloud consumer compliantly to its requirements. The cloud consumeris still not confident in cloud computing and prefers to have his own infrastructure. This paper is thus proposed to boost trust in cloud services. We propose an architecture for cloud brokering that implements dependability properties as a mean for trust assurance. © 2015 IEEE. Source

Hamouda S.,MEDIATRON Laboratory | Chaabane I.B.,MEDIATRON Laboratory | Tabbane S.,MEDIATRON Laboratory
IEEE Transactions on Vehicular Technology | Year: 2015

Heterogeneous networks (HetNets) are likely to provide ubiquitous access to mobile broadband services as they involve various small cells, each targeting a different environment in the network. In this paper, we are interested in improving the system performance at the cell edge. Hence, we consider a HetNet composed of an eNodeB (eNB) coexisting with different relay nodes (RNs) situated at the cell border. We propose a cooperative physical resource blocks (PRBs) sharing scheme in a dual-hop LTE-Advanced in which every node can transmit on some of the PRBs assigned to a coexisting node without causing it harmful interference. To do so, we use a powerful mathematical tool, i.e., game theory. First, we consider two nodes in the macrocell and define a new repeated game in which a selfish node is encouraged to cooperate under the threat of punishment. Then, we enlarge the number of RNs in the network and find the optimal pairs of nodes that will cooperate, due to a new coalition formation game. Simulation results show that the proposed cooperative PRB sharing scheme significantly improves the utilization of the spectrum and the achieved total throughput in the system. We also demonstrate that both games rapidly attain Pareto efficiency. © 1967-2012 IEEE. Source

Discover hidden collaborations