Modélisation et simulation des réseaux mobiles de 4ème génération

Cette thèse porte sur l'interopérabilité et la qualité de service dans les réseaux de 4ème génération. En particulier, nous proposons des solutions d'intégration entre le réseau WiMAX et le système satellite DVB-RCS en s'appuyant sur le standard IEEE 802.21. Trois solutions peuvent être mises en place pour l'interconnexion de réseaux sans fil. Il s'agit de la technologie GAN soutenue par le 3GPP, du protocole FMIP proposé par l'IETF et du standard IEEE 802.21. Notre choix se porte sur ce denier standard car il propose un cadre générique pour l'interopérabilité des réseaux. En fait, nous proposons une architecture satellitaire à base de WiMAX, DVB-RCS et IEEE 802.21 et nous décrivons aussi la procédure de handover WiMAX/DVB-RCS. Par ailleurs, nous améliorons les performances des réseaux WiMAX en utilisant un handover horizontal avec un mécanisme de réservation de ressources. Ensuite, le réseau WiMAX est intégré dans un système satellite DVB-RCS afin d'étudier les performances de cette convergence avec une réservation de ressources. Les résultats obtenus montrent que les mécanismes de réservation améliorent les performances. Afin de permettre au trafic de passer d'un réseau à l'autre en garantissant une qualité de service, une mise en correspondance de la qualité de service entre les réseaux WiMAX et DVB-RCS est proposée. En outre, nous proposons un mécanisme d'admission de connexion CAC dans le cadre de l'interconnexion WiMAX/DVB-RCS. Plusieurs stratégies sont prises en compte afin de permettre une coopérative efficace entre les deux systèmes. ABSTRACT : This PH.D thesis is based on the interworking and the quality of service in 4th generation mobile wireless networks. In particular, we propose solutions of integration between WiMAX networks and satellite systems (DVB-RCS). Three solutions can be considered for the interconnection of wireless networks: GAN technology supported by the 3GPP, FMIP protocol suggested by the IETF and the IEEE 802.21 standard. Our choice is focused on this last standard because it proposes a generic framework for the interworking of wireless networks. A procedure of handover WiMAX/DVB-RCS is then described. In addition, we improve the performance of WiMAX networks by using a horizontal handover with resource reservation mechanisms. Then, the WiMAX network is integrated in a DVB-RCS satellite system. The performance of this convergence with a resource reservation mechanism is studied. The obtained results show that the reservation mechanisms improve the performance of the system. In order to switch the traffic from one network to the other by guaranteeing an appropriate level of quality of service, a mapping of quality of service between WiMAX networks and DVB-RCS system is proposed. Moreover, we propose a Connection Admission Control (CAC) mechanism within the framework of the WiMAX/DVB-RCS interconnection. Several strategies are taken into account in order to allow an effective co-operative between the two system

Comparison of the Proactive and Reactive Algorithms for Load Balancing in UDN Networks

OA-lehti, jossa ei rinnakkaistallennusmahdollisuutta.Ultra-Dense Networks (UDNs) were introduced to support high data rate services and improve the network capacity. The load across the small cells is unevenly distributed owing to random deployment of small cells, the mobility of user equipments (UEs) and the preference of small cells during the selection/reselection. The unbalanced load causes performance degradation in both the throughput and successful handovers. Moreover, it may be responsible for radio link failures as well. To address this problem, this paper proposes different proactive algorithms to balance the load across UDN small cells and compare them to previous reactive algorithms. Proactive algorithms distribute the UEs, one by one, to the access points (APs), while the reactive ones are only triggered when the load of the chosen small-cell cluster reaches a predefined threshold. The numerical analysis shows that the load distribution achieved by the proactive algorithm with user rejection is better than that in the reactive algorithms by 34.97%.In addition, the impact of the small-cell cluster layout on the load balancing results is also studied in this paper. The results indicate that the load distribution and the balance improvement ratio in the intersecting small-cell model outperform those in the sequential small-cell one by 48.98% and 22.43%, respectively.Peer reviewe

تقييم أداء التسليم الشاقولي بين الشبكاتWiFi و WiMax باستخدام تقنية التسليم المستقل عن الوسط MIH

تتجه الأبحاث الحالية نحو المزيد من التطوير في الشبكات اللاسلكية، وذلك نتيجة النمو في احتياجات المستخدمين كدعم تطبيقات الزمن الحقيقي، وجودة الخدمة وخصوصاً معدل نقل عالي للبيانات، وغيرها. ما دفع بمزودي خدمة الشبكات العمل على مكاملة العديد من موارد الشبكات المختلفة، والسعي لدعم خدمة الاتصال في أي مكان وزمان. من هنا تأتي أهمية هذا البحث الذي يهدف إلى دراسة عملية التسليم الشاقولي(Vertical Handover) كخطوة مهمة وضرورية لتأمين حركة العقد المتحركة MN(Mobile Nodes) بين الشبكات اللاسلكيةWiFi وWiMax باستخدام المعيار IEEE802.21، أو ما يسمى تقنية التسليم المستقل عن الوسط MIH (Media Independent Handover)، والذي طُوّر في كانون الثاني 2009.في هذا البحث، تم تقييم أداء التسليم الشاقولي بين هاتين الشبكتين آخذين بالاعتبار عدة معاملات مثل: ضياع البيانات، والتأخير الناتج عن عملية التسليم، ومعدل التدفق. وذلك باستخدام المحاكي(NS2(Network Simulator version2))والذي يتضمن دعم لتقنية MIH من قبل المعهد الوطني للمعايير والتقانة (NIST)National Institute of Standard and Technology .

Load balancing algorithm within the small cells of heterogeneous UDN networks

Ultra-Dense Networks (UDNs) can be used to improve coverage. With limited network capacity and the dense development of wireless networks, heterogeneous ultra-dense networks are set to satisfy the increasing demands of mobile users. However, the dense deployment of small cells in the hotspots of UDN networks generates an uneven traffic distribution. To address this problem, this paper proposes novel load balancing approaches implemented within the small cells, which are formed based on the Radio-over-Fiber (RoF) system. To select the best overlapping zone and then the best candidate user to be handed-over between the access points of the small cells, a common zone approach, a worst zone approach and a mixed approach are suggested. The results indicate that the proposed algorithm improves the performance of UDN networks when the load is unbalanced. The balance improvement ratio can reach on average 89.16%.Peer reviewe

Load migration mechanism in ultra-dense networks

As one of the main technologies in 5G networks, Ultra-dense networks (UDNs) can be used to improve the network coverage. The dense deployment of small cells in UDN hotspots generates an uneven traffic distribution. In this paper, we propose a novel mechanism in order to transfer the extra users from the small cells to the macrocells based on several load balancing approaches implemented within the small cells, which are formed based on the Radio-over-Fiber (RoF) system. To select the best overlapping zone and then the best candidate user to be handed-over between the access points of the small cells, a common zone approach, a worst zone approach and a mixed approach are proposed. With the objective of transferring the extra users to the macrocells, we suggest a transfer after approach, a transfer before approach and an active approach. The simulation results indicate that the proposed approaches succeed to balance the load among the access points and to migrate the required load from the overloaded small cells to the macrocells in selective way. In some cases, the balance improvement ratio can reach 97.94%. Moreover, the overall balance efficiency is increased by 51.32% compared to the case without transferring users to the macrocells.Peer reviewe

Modélisation et simulation des réseaux mobiles de 4ème [quatrième] génération

La thèse s'est concentrée sur l'interopérabilité entre le réseau wiMAX et le système satellite DVB-RCS. Les travaux ont porté sur l'architecture et les protocoles liés mais encore sur la définition de mécanismes visant à garantir de la qualité de service.The thesis focuses on the wiMAX network and DVB-RCS satellite system interworking. The work is based on the architecture and related protocols and also on the definition of mechanisms in order to guarantee the quality of service.TOULOUSE-ENSEEIHT (315552331) / SudocSudocFranceF

Performance of WiMAX Networks using Horizontal Handover with Channel Reservation Mechanism

International audienceNext generation networks will be characterized by variable and high data rates, QoS, and seamless mobility, within a network and between heterogeneous networks with different technologies and service providers. In this paper, we consider a model of mobility for WiMAX network users introducing horizontal handover mechanism with channel reservation. We take into account several approaches in order to carry out the reservation. We evaluate the performance of the proposed model. The results show, by means of simulation, that channel reservation mechanism improves horizontal handover without reducing the performance of the system

Performance of WiMAX Networks Integrated in a Segment of Satellite using Channel Reservation Mechanism

International audienceMobility issue and service continuity represent important challenges for next generation networks. The integration of a satellite segment within a terrestrial network (especially WiMAX) has several advantages in a 4G context. In this paper, we focus on channel reservation mechanisms to ensure quality of service. Primary results show, by means of simulation, the gains and limitations of each mechanism. It is shown that the best results are obtained when the mechanisms are performed by the base stations when the density of users is low. Otherwise, cooperative solutions for which reservations are done by neighboring nodes may improve the performance of the system

QoS Mapping and Connection Admission Control in the WiMAX / DVB-RCS Access Network

Workshop @ 12th ACM International Conference on Modeling, Analysis and Simulation of Wireless and Mobile Systems (MSWiM 2009)International audienceThe quality of service (QoS) represents an important challenge for next generation networks such as systems composed of terrestrial infrastructure based on worldwide interoperability for microwave access (WIMAX) and satellite segments using Digital Video Broadcast with Return Channel via Satellite (DVB-RCS). Both systems have to cooperate in a 4G context. Connection admission control (CAC) is required to ensure QoS. In this paper, we focus on the class-of-service mapping and on CAC procedures in the WiMAX/DVB-RCS cooperative system. Several strategies are proposed in order to transfer the connection between these two systems. A greedy strategy is taken into account to share the capacities of both satellite and terrestrial access networks. This strategy allows a large number of satellite users to be transferred to the WiMAX network