Mohamed Aissa

A new delay-constrained algorithm for multicast routing tree construction

New multimedia applications provide guaranteed end-to-end quality of service (QoS) and have stringent constraints on delay, delay-jitter, bandwidth, cost, etc. The main task of QoS routing is to find a route in the network, with sufficient resources to satisfy the constraints. Most multicast routing algorithms are not fast enough for large-scale networks and where the source node uses global cost information to construct a multicast tree. We propose a fast and simple heuristic algorithm (EPDT) for delay-constrained routing problem for multicast tree construction. This algorithm uses a greedy strategy based on shortest-path and minimal spanning trees. It combines the minimum cost and the minimum radius objectives by combining respectively optimal Prims and Dijkstras algorithms. It biases routes through destinations. Besides, it uses cost information only from neighbouring nodes as it proceeds, which makes it more practical, from an implementation point of view. Copyright

New Strategies and Extensions in Weighted Clustering Algorithms for Mobile Ad Hoc Networks

Abstract We study the problem of constructing a novel framework for dynamically organizing mobile nodes in wireless ad-hoc networks into clusters where it is necessary to provide robustness in the face of topological changes caused by node motion, node failure and node insertion/removal. The main contribution of our work is a new strategy for clustering a wireless AD HOC network and improvements in WCA (Weighted Clustering Algorithm) [3] , a well-known algorithm. We first derive mathematically a new cluster size bound to replace δ in WCA and a simple node stability model. Thereafter, we prove their efficiencies. Our contribution also extends previous work to replace the degree- difference used initially in WCA to provide load-balance in wireless AD HOC with a new more efficient and consistent model which helps to decrease the number of clusters. We show that our algorithm outperforms WCA in terms of cluster formation and stability. The non-periodic procedure for clusterhead election is invoked on-demand, and is aimed to reduce the computation and communication costs. We strive to provide a trade-off between the uniformity of the load handled by the clusterheads and the connectivity of the network.

Quality of Clustering in Mobile Ad Hoc Networks

Abstract We consider the problem of appropriate clusterhead selection in wireless ad-hoc networks where it is necessary to provide robustness in the face of topological changes caused by node motion, node failure and node insertion or removal. The main contribution of our work is a new strategy for clustering a wireless AD HOC network and improvements in WCA and other similar algorithms. We first derived some analytical models and thereafter some clustering schemes. Our contribution also extends previous works in providing some properties and analyses of Quality of Clustering (QoC) in AD HOC. We showed that our algorithm outperforms the Weighted Clustering Algorithm (WCA) in terms of cluster formation and stability. One of the main ideas of our approach is to prioritize favourable nodes in clusterhead election and re-election processes. We strived to provide a trade-off between the uniformity of the load handled by the clusterheads and the connectivity of the network.

Cluster Connectivity Assurance Metrics in Vehicular ad hoc Networks

Abstract Many applications introduced by Vehicular Ad-Hoc Networks (VANETs), such as intelligent transportation and roadside advertisement, make VANETs become an important component of metropolitan area networks. In VANETs, mobile nodes are vehicles which are equipped with wireless antennas; and they can communicate with each other by wireless communication on ad-hoc mode or infrastructure mode. Clustering vehicles into different groups can introduce many advantages for VANETs as it can facilitate resource reuse and increase system capacity. The main contribution of our work is a new strategy for clustering a VANET and improvements in many classical clustering metrics. One of the main ideas is the definition of a new optimized selection metric for the clustering of vehicular nodes, in the framework of Next Generation Vehicular ad-hoc Network. These metrics should select clusterheads which provide safe clusters and avoid collisions with adjacent vehicle nodes and intend to create stable clusters by reducing reclustering overhead and prolonging cluster lifetime

A Novel Multicast Algorithm for Collaborative Multimedia Applications in Heterogeneous Networks

Abstract In this paper, we study the problem of QoS group communication in a heterogeneous network, which consists of multiple MANETs attached to the backbone Internet. We propose a heuristic multicast algorithm called MCMA (Multi-Constrained Multicast Algorithm). MCMA is designed for solving the DVBMT (Delay-and delay Variation-Bounded Multicast Tree) problem, which has been proved to be NP-complete. The literature studies are limited to end-to-end delay bound and delay variation minimization. In this paper, we improve and extend previous well known from literature heterogeneous network algorithms to provide scalable and stable multicast services on the Internet by introducing a new Delay–Variation Estimation Scheme for heterogeneous networks. This Scheme helps the MCMA algorithm achieve better performance in terms of the multicast delay variation than some well-known algorithms. The algorithm defines QoS parameters as constraints on both delay and delay variation. Theoretical analysis is given to show the correctness of MCMA and its performance in terms of the multicast delay variation.

A new scalable multicast routing algorithm for interactive real-time applications

Quality of service (QoS) provisioning generally assumes more than one QoS measure that implies that QoS routing can be categorized as an instance of routing subject to multiple constraints: delay jitter, bandwidth, cost, etc. We study the problem of constructing multicast trees to meet the QoS requirements of real-time interactive applications where it is necessary to provide bounded delays and bounded delay variation among the source and all destinations while keeping overall cost of the multicast tree low. The main contribution of our work is a new strategy for constructing multiconstrained multicast trees. We first derive mathematically a new delay-variation estimation scheme and prove its efficiency. Thereafter, we propose a simple and competitive (in terms of running time) heuristic algorithm, for delay and delay variation constrained routing problem based on the proposed delay-variation estimation scheme and using the Extended Prim-Dijkstra tradeoffs’ algorithm. Our contribution also extends previous works in providing some properties and analyses of delay bounded paths satisfying delay variation constraints. Extensive simulation results show that our algorithm outperforms DVDMR in terms of multicast delay variation with the same time complexity as DVDMR.

M2M performance metrics: Challenges, solutions and research opportunities

Machine-to-machine (M2M) communications have emerged as a cutting edge technology for next-generation communications, and are undergoing rapid development and inspiring numerous applications. Machine-to-machine (M2M) communications could enable machines to exchange information without the direct human intervention. Machines in M2M systems could not only collect data for their own use, but also share the data with other machines intelligently. Therefore, M2M communications could be employed efficiently in smart grid, vehicular network, as well as real-time monitoring of patients in e-healthcare system, and so on. This contribution highlights the challenges which arise from M2M performance metrics. We extend our work to highlight the most recent solutions for these challenges and research derived from literature.

New Strategies and Approaches for Efficient Overlay Multicast Routing

Abstract In many group-oriented media streaming applications, overlay multicast (also called Application-layer multicast) is utilized as an alternative technology for IP multicast, which suffers from various issues such as group management, congestion and flow control, and security. Recent researches on overlay networks have revealed that user-perceived network performance, such as end-to-end delay performance, could be improved by an overlay routing mechanism. However, these studies only consider end-to-end delay, or only bandwidth, and there are few works focusing on delay variation constraint. We proposed an algorithm, which defines an optimal balance tree to optimize a trade-off between delay and bandwidth consumption with constraints on both delay and delay variation. Furthermore, we introduce a new Delay–Variation Estimation Scheme and core selection strategies for multicast routing in leased overlay networks.

An efficient core selection algorithm for delay and delay-variation constrained multicast tree design

We propose new strategies in core selection methods and core-based tree (CBT) construction based on new methods of computing delay variation. As a result, we propose an algorithm, which guarantees that the delay from the source to any destination does not exceed a real-time constraint. Furthermore, we address the problem of satisfying the delay variation constraint under cost minimization. We present a new core and path selection methods that take both cost and delay simultaneously into consideration. Thus, we achieve a balance of optimizing cost and delay of the multicast tree. The problem is known to be as NP-complete. A solution to this problem is required to provide decent real-time communication services such as on-line gaming, shopping, and teleconferencing.

Overview of machine-type communications traffic patterns

A concise overview of Machine Type communication (MTC) is presented to encompass the various traffic patterns and models from the literature. Since M2M applications may well be generating huge traffic and resulting in bandwidth intensive transactions vying for priority, network operators must obviously be concerned about the handling of the enormous escalation in their signalling traffic and, in particular, finding new ways to satiate the M2M applications, improve the efficiency of resource utilization and effectively control service level agreements. Hence, in order to efficiently design and thereby control the future Internet needs one must take stock of the principal traffic attributes. This contribution brings forward an overview of MTC traffic patterns.