Mounir Frikha

Hierarchical mobile IPv6 based architecture for heterogeneous wireless networks interworking

The demand for accessing services while on the move, at any place and time, has lead to the current efforts towards integration of heterogeneous wireless networks, in particular UMTS, WiMAX and WLAN, as complementary systems. Integration can be performed at different levels: tight coupling and loose coupling. The paper presents the design and evaluation of a HMIPv6 based architecture for different wireless networks interworking. Our proposed architecture aims to solve the problems existing in present interworking solutions, such as congestion in the UMTS core network.

A fair and power saving uplink scheduling scheme for 3GPP LTE systems

In this paper, we propose an uplink resources allocation strategy for Long Term Evolution (LTE) systems. In time domain, the scheduler aims at ensuring more fairness by using a metric updated every new uplink transmission round, giving higher priority to users who are the farthest from their minimum QoS requirements. Then, resources are allocated in a way to achieve the required rate with the minimum number of resources blocks, respecting channel quality and power limit. Obtained results prove that the proposed scheme helps the system to fairly and efficiently redistribute the available radio resources and to reduce uplink power consumption.

Loose coupling approach for UMTS/WiMAX integration

Fourth generation (4G) Network integrates existing wireless technologies (GPRS/UMTS, WiMAX, WLAN, etc.) and offers access to services while on the move, at any place and any time. A multi-interface device can switch connection among available access points implementing different technologies. Integration of heterogeneous wireless networks can be performed at different levels (open coupling and tight coupling.). This paper presents a loose coupling approach to interconnect UMTS and WIMAX systems.

Towards a study of mobility models impact on VANET connectivity metrics

Vehicular Ad Hoc Networks (VANETs) are a subclass of mobile ad hoc networks that have emerged recently as a platform to support intelligent inter-vehicle communication and to improve active safety, traffic management, and performance. The knowledge of the topological characteristics of the underlying network is an important factor we should take care of because it can greatly affect the design and development of efficient VANET protocols. As a matter of fact it influences the connectivity of vehicular networks. In this paper, we present an analysis of the influence of mobility models on the topological characteristics of a VANET network by using different connectivity metrics such as lobby index, betweenness centrality and local clustering coefficient. Such parameters could be used for example in choosing the next hop in dissemination protocols.

Implementation and Performance Evaluation of an Energy Constraint Routing Protocol for Mobile Ad Hoc Networks

The aim of this paper is to evaluate the performance of an energy aware routing protocol, called ECB-AODV (Energy Constraint protocol Based on AODV) which derives from the AODV protocol and which is based on the local decisions of intermediate stations to maintain the connectivity of the network as long as possible. The results obtained using the network Simulator NS-2 demonstrate how small changes in the principle of the AODV protocol can efficiently balance the energy consumption between nodes, which increases the network lifetime.

On the Performance of MANETs under Different Mobility Patterns and Routing Protocols and Its Improvement Based on Fixed Relay Nodes

Mobile Ad Hoc Networks (MANETs) are wireless networks where (user) nodes act themselves as relays to other nodes, resulting in a variable topology that follows the users mobility pattern. The latter can vary from one context to another resulting in different network performance, in terms of throughput for instance. This is the rationale behind the present work where we, first, quantify the performance of the network under different mobility patterns and routing protocols, and where we, second, propose the use of fixed relays so as to enhance the performance in case of ill-behaved mobility schemes.

Proposition and analysis of multi channel cognitive MAC protocols with parallel transmission of traffic and UWB control information

Cognitive radio and UWB technologies are new radio designs philosophies in order to optimize the spectrum utilization by exploiting the unused and the under-used spectrum in dynamically changing environments. Although the contrasting philosophies of cognitive radio and UWB technology gains can be made by merging these two technologies. In this paper we propose a cognitive radio based on two MAC protocols which work in a cooperative manner. The first is a MAC UWB protocol for control information transmission, while the second is a MAC protocol for narrow or large band traffic transmission (which depend on the primary user physical implementation). We prove then by analyzing the No real time and the real time Markov chains the efficiency of the CS-OFDMA with pre-reservation access protocol to decrease the Forced termination probability and to increase the throughput of cognitive nodes.

Hybrid QoS based routing protocol for inter and intra wireless mesh infrastructure communications

Quality of service (QoS) in wireless mesh networks is an active area of research, which is driven by the increasing demand for real-time and multimedia applications, such as Voice over IP and Video on Demand. In this paper, we propose a novel QoS based routing protocol for wireless mesh infrastructure, called Hybrid QoS Mesh Routing (HQMR). It is composed of two QoS based routing sub-protocols: a reactive multi-metric routing protocol for intra-infrastructure communications and a proactive multi-tree based routing protocol for communications with external networks. The proposed routing protocol enables forwarding real-time and streaming applications with QoS guarantee in a mesh wireless environment, by assigning a specific routing path for each defined service class. To this end, three different QoS service classes are defined, depending on the applications requirements. We analyze in this paper the simulation results of different scenarios conducted on the network simulator ns-3 to demonstrate the effectiveness of the HQMR protocol and to compare it to other routing protocols while forwarding real-time applications with QoS guarantee.

Performance of Delay Tolerant Mobile Networks and its improvement using mobile relay nodes under buffer constraint

The performance of Delay Tolerant Mobile Networks (DTMNs) depends on the mobility pattern through the nodes encounter process which constitutes opportunities for exchange of information between nodes. However, the exchange of information itself depends also on the routing/replication protocol and the network resources as the node buffer capacity and which determines the effective network performance. We focus in this work on those two concepts: encounter and exchange, and evaluate them along with resulting network performance for different mobility patterns and routing protocols as well as under the limited buffer space constraint. We also propose the use of additional, mobile, dedicated relays so as to enhance the performance of the DTMN in cases of ill-behaved mobility schemes.

Flow level modelling of Internet traffic in Diffserv queuing

While Internet traffic is currently dominated by elastic data transfers, it is anticipated that streaming applications will rapidly develop and contribute a significant amount of traffic in the near future. Therefore, it is essential to understand and capture the relation between stream and elastic traffic behavior. In this paper we focus on developing simple yet effective approximations to capture this relationship. We study, then, an analytical model to evaluate the performance of elastic traffic under Diffserv architecture. This model is based on the fluid flow approximation. We assume that Diffserv architecture gives the head of priority to real time traffic and shares the remaining capacity between the elastic ongoing flows according to a specific weight.