Nabil Tabbane

A Fuzzy Multi-Metric QoS-Balancing Gateway Selection Algorithm in a Clustered VANET to LTE Advanced Hybrid Cellular Network

Intelligent transportation systems are currently attracting the attention of the research community and the automotive industry, which both aim to provide not only more safety in the transportation systems but other high-quality services and applications for their customers as well. In this paper, we propose a cooperative traffic transmission algorithm in a joint vehicular ad hoc network-Long Term Evolution Advanced (LTE Advanced) hybrid network architecture that elects a gateway to connect the source vehicle to the LTE Advanced infrastructure under the scope of vehicle-to-infrastructure (V2I) communications. The originality of the proposed fuzzy quality-of-service (QoS)-balancing gateway selection (FQGwS) algorithm is the consideration of QoS traffic class constraints for electing the gateway. Our algorithm is a multicriteria and QoS-based scheme optimized by performing the fuzzy logic to make the decision on the appropriate gateway. Criteria are related to the received signal strength (RSS) and load of the cluster head (CH) and gateway candidates (GwCs), as well as the vehicle-to-vehicle link connectivity duration (LCD). Simulation results demonstrate that our algorithm gets better results than the deterministic scheme for gateway selection. Moreover, results show the efficiency of the FQGwS algorithm as it adapts its gateway selection decision to the cluster density and the relative velocity of the source node.

Performance Analysis of SCTP Protocol in WiFi Network

The Internet Protocol Stack provides a set of transport layer protocols. There are two dominant types of transport layer protocol used in the Internet: UDP (User Datagram Protocol) and TCP (Transmission Control Protocol). The transport layer provides end-to-end information transfer across a network with the quality of service needed by the application. In this paper, we provide a performance comparison of SCTP, TCP and UDP protocols in WLAN environments for different traffic flow: VoIP, video streaming and data traffic. The performance metrics used for this evaluation include throughput, end to end delay and packet loss rate. The comparison of performance of SCTP, UDP and TCP are done using the Network simulator NS-2.

Fuzzy logic based layers 2 and 3 handovers in IEEE 802.16e network

In outdoor wireless communication networks such as mobile WiMAX (802.16e), mobile stations move all the time, thus they need to be handed off to different base stations based on certain criteria. In this paper, a fuzzy logic based scheme for fast selection of best base station and of handover technique at the handover time is presented in order to minimize the delay during handover for sensitive multimedia traffic. The scheme considers several parameters such as receiver power levels, handover type, traffic type, base station load and mobile station speed for making the handover decision by the mobile station. Through simulations, we compare our proposed handover scheme based on fuzzy logic modeling with classical handover decision. And finally, we present results based on Quality of Service (QoS) criteria to confirm the validity of the proposed approach.

LTE Advanced Relaying Standard: A Survey

Long term evolution (LTE) Advanced is a well designed system that meets the requirements of 4G cellular systems. Its standard specification has been lately released. One of its main features is supporting relaying topology inspired from ad hoc multihop networks. This paper is a survey upon the relaying architecture of LTE Advanced standard based on 3GPP Release 10 specifications. A comparison with other relaying architectures, i.e. IEEE 802.16m and IEEE 802.11s is handled. The originality of this work is in involving comparison with multihop architecture supported by IEEE 802.11s based wireless mesh networks. Several similarities are noted and differences are pointed out.

A framework for automatic web service discovery based on semantics and NLP techniques

As a greater number of Web Services are made available today, automatic discovery is recognized as an important task. To promote the automation of service discovery, different semantic languages have been created that allow describing the functionality of services in a machine interpretable form using Semantic Web technologies. The problem is that users do not have intimate knowledge about semantic Web service languages and related toolkits. In this paper, we propose a discovery framework that enables semantic Web service discovery based on keywords written in natural language. We describe a novel approach for automatic discovery of semantic Web services which employs Natural Language Processing techniques to match a user request, expressed in natural language, with a semantic Web service description. Additionally, we present an efficient semantic matching technique to compute the semantic distance between ontological concepts.

Performance Evaluation of Greedy Perimeter Stateless Routing Protocol in Ad Hoc Networks

Several geographic routing protocols using location information have already been proposed for ad hoc networks in order to improve performance of ad hoc routing protocols. Here we can mention the case of Greedy Perimeter Stateless Routing (GPSR) protocol. GPSR makes greedy forwarding decisions using merely information about a router’s immediate neighbors in the network topology. In case a packet reaches a region where greedy forwarding is impossible, the algorithm recovers by routing around the perimeter of the region. This paper presents the performance evaluation of GPSR protocol for its qualities of scaling and its good performance even at high mobility. We simulated the protocol by using the Hierarchical Location Service (HLS) which is purely geographical in its strategy for selecting and updating the location servers. The performance evaluation is based mainly on three network metrics: Packet Delivery Ratio (PDR), Traffic Overhead (TOH) and End to End Delay (EED). We have focused on the variation effects of a network parameters set such as: the number of mobile nodes, the network load, speed nodes and inter-beacon interval.

A multi-metric QoS-balancing scheme for gateway selection in a clustered hybrid VANET network

In this paper, we propose a cooperative traffic transmission algorithm in a joint cellular and mobile ad hoc hybrid network architecture. The mobile ad hoc network is based on IEEE 802.11p standard. The focus of this paper is on defining an algorithm aiming to select the appropriate gateway for a given source vehicle under the scope of V2I communications. In this work, we consider the LTE Advanced infrastructure. We propose a multi-criteria and attribute scheme used to make a decision over the appropriate gateway to connect a source vehicle to the LTE Advanced infrastructure. It is a QoS-balancing gateway selection algorithm where the decision over the gateway depends on the traffic to be transmitted to the infrastructure. Other criteria are also considered such as loads, Received Signal Strengths (RSS) and Link Connectivity Durations of the cluster head and other gateway candidates. Simulation results demonstrate that our algorithm makes efficient decisions for electing the appropriate gateway that fits best the cluster and infrastructure features. An improvement of the RSS and the Link Connectivity Durations, while comparing to the commonly used gateway selection scheme, is noted.

Discovery of semantic Web Services with an enhanced‐Chord‐based P2P network

Currently Web Service (WS) systems are based on central registries for publication and discovery. With the growing number and the dynamicity of WS, this centralized approach rapidly becomes inefficient and impractical. Furthermore, existing WS standards such as WS Description Language (WSDL) and Universal Description, Discovery and Integration (UDDI) do not support semantic description which is essential for the automation of several WS-related functions such as discovery, execution and composition. We propose a system that enables efficient Semantic WSs publication and discovery in a fully decentralized network using peer-to-peer technologies. We also propose and evaluate the performances of an enhanced version of Chord protocol that we have called ‘enhanced-Chord’. Copyright

VOPP: A VANET offloading potential prediction model

In this work, we investigate upon the potential of considering the Intelligent Transportation Systems (ITS) for cellular traffic offloading as an alternative to Wi-Fi and femtoCells approaches. We propose an analytical study based on an optimization problem formulation called VOPP where the objective is to elect the maximum number of data flows that could be routed to the downloaders through the Vehicular Network (VANET). VOPP considers the link availability between the infrastructure and the downloader, the medium contention, interferences, data volume, gateways capacity and the channel aggregation to evaluate the VANET capacity to support additional traffics. Numerical results of our analytical approach show that the data offloading fraction is closely tied to the data volume of the flows and to the vehicles positions and VANET topology.

VANET Inherent Capacity for Offloading Wireless Cellular Infrastructure: An Analytical Study

Due to the high user traffic demand increase, offloading cellular traffic through other kinds of networks, such as Wi-Fi hotspots and femtoCells has been highly studied. In this paper, we investigate upon the possibility to use Vehicular ad hoc Networks (VANETs) for the offloading the cellular infrastructure. We present an analytical study based on an optimization problem formulation where the aim is to select a maximum target set of flows that could be routed to the destination downloader node through the VANET network. The offloading decision considers the vehicular link availability, channel load by considering medium contention, vehicle to vehicle link quality and the link connectivity duration between the VANET node and the road side unit. Simulation results of our analytical approach show that the data offloading fraction is closely affected by the data volume of the flows, the channel load and by the link quality. Results show also that the offload of best effort data traffics could reach 100 percent for low data volumes.