Les handovers sont des phénomènes inévitables dans les réseaux sans-fil mobiles. Lors du passage d'une station mobile d'un point d'accès à un autre, le handover affecte la qualité des transmissions, et ainsi, il est néfaste à la performance des réseaux sans-fil. De nombreuses techniques de réduction du délai lié au handover ont été proposées, mais la plupart ne sont pas adaptées aux attentes du nouveau type de réseau sans-fil mobile qu'est le réseau véhiculaire. Ce travail propose donc l'implémentation d'une méthode de réduction du délai encouru lors d'un handover dans les réseaux véhiculaires qui opèrent sous une technologie d'accès sans-fil adaptée pour les besoins des réseaux véhiculaires. Le travail est composé de deux blocs : le premier est l'implémentation d'IEEE 802.11p, qui est une variante de la norme générique d'IEEE 802.11 et qui est développée spécialement pour l'accès dans les réseaux véhiculaires, dans un simulateur de réseaux. L'autre partie concerne le choix d'une méthode de réduction du délai lié à l'étape de la recherche du handover. En tenant compte des réalités technologiques, le choix s'est porté sur une technique préconisant l'utilisation des cache pour contenir et diffuser de l'information sur les points d'accès avoisinants. La méthode proposée a été testée et a donné de très bons résultats réalistes. L'intégration des modules complémentaires pour refléter l'ensemble de la technique proposée au niveau du simulateur s'est aussi faite sans problèmes majeurs.

The most prevailing feature that led to the massive success of current Wireless Mobile Tele-Communication systems, is mobility. Being able to communicate on the go, anywhere and anytime has revolutionized modern day communication. In recent times the focus has not been only on simply being reachable while on the move but at the same time to use a variety of rich media content services over a variety of available network technologies, termed as 4G networks. The telecommunication development from the very beginning took two different tracks. One was the Internet which provided a fixed means of communication delivering rich media content taking full advantage of its packet switched nature. The second track was that of the cellular systems taking advantage of their circuit switched nature providing mainly voice and short messaging services to wireless and mobile users. In time both these technologies made major advances following their own respective tracks and it became evident that the convergence of both these technologies would be of even greater value. The driving force for this convergence was that a great need was felt for the support of mobility in the Internet. But since the Internet was not designed keeping mobility in mind, it did not support mobility by design. On the other hand in cellular systems in addition to circuit switching, packet switching was needed for flexibility, to make better use of network resources, and to deliver rich media content to the user at cheaper prices. For non-mobile user’s, packet switched networks performed really well in providing the required Quality of Service (QoS). However such networks faced considerable problems to achieve similar QoS for mobile users. With no support for mobility in the Internet from scratch, new components and functionalities were needed to be incorporated into the Internet for mobility support. Examples of such functionality include location tracking, network discovery, packet re-routing to the current point of attachment of the Mobile Node (MN), accounting, authorization and authentication. Special mobility management protocols to provide the required new functionalities were needed. For this purpose the Internet Engineering Task Force (IETF) proposed Mobile IP version 4 (MIPv4) and Mobile IP version 6 (MIPv6) to support mobility for a single IP host and Network Mobility (NEMO) protocol to support mobility for a whole network in motion. These protocols have the ability to maintain data connections for mobile IP enabled devices when they roam across different subnets or networks. When a mobile user moves across network boundaries, it has to perform handover to maintain its connections. When performing a handover a MN may not be able to send or receive data packets therefore the handover duration becomes a critical factor in guaranteeing real time applications (e.g. Voice over IP (VoIP)) their QoS. The purpose of this research work is to deal with handover issues in packets switched networks. A stepwise approach was followed during this study. Starting at layer-2 of the TCP/IP protocol stack and after identifying major problems at this layer for 802.11 networks, solutions were devised for seamless handovers by utilizing the Media Independent Information Service (MIIS) of the Media Independent Handover (MIH). After dealing with major handover issues at the MAC layer of 802.11 networks, the work moved one layer up in the TCP/IP protocol stack to layer three or the IP layer. The MIH framework which was originally proposed for vertical handovers is proposed to be utilized for improving the efficiency of horizontal handovers. Keeping the research work focused on horizontal handovers in 802.11 networks only, an Access Point (AP) selection scheme is proposed and an investigation was carried out regarding the implications of proposed solutions at the MAC layer, on MIPv6 handover delays. In the next step, the study is extended to vertical or heterogeneous handovers. This part proposes to break up a heterogeneous handover algorithm in a Wi-Fi/WiMAX integrated environment, into two parts. The handover algorithm parts are proposed to be executed separately from each other distributed among multiple network components, resulting in intelligent resource utilization and good scalability, without sacrificing handover efficiency. For proof of concept and the effectiveness of the proposed schemes simulations were performed in Network Simulator-2 (ns-2) for a scenario in which a MN moves linearly in the topology, performs handovers and makes use of MIH facilities for improved handovers. An important portion of this research also deals with the analysis of a variety of NEMO route optimization schemes proposed in the literature and their implications on handovers in NEMO networks. The goal of this part is to overview the handover signaling complexity of the various proposed NEMO route optimization schemes.

Em NGN (Next Generation Networks), os usuários podem se conectar em diferentes tecnologias de rede e desejam, além de uma comunicação transparente, novos serviços personalizados. Neste sentido, este trabalho explora informações de contexto em NGN. O principal objetivo é capturar as informações de contexto envolvidas no momento da utilização da rede sem fio, na escolha do novo ponto de acesso e no procedimento do handover. Este contexto capturado é aplicado para serviços cientes de contexto. A proposta é validada por meio de dois cenários, o primeiro é um mashup que exibe as redes sem fio disponíveis de um determinado local e o segundo um protótipo gerenciador de conexões para atender as preferências do usuário. Adicionalmente, são realizadas duas avaliações do impacto do uso de contexto em handovers. Para tanto, foi implantado um testbed NGN com o protocolo Mobile IP / In the NGN (Next Generation Networks) users can connect their Internet devices to different network technologies. In addition to a seamless communication, users desire new and personalized services. In this sense, this thesis exploits the context-aware information in NGN environments. The main propose is to capture the context information about the time involved by the use of wireless link for selecting the target access point and on the handover procedure. This context information is applied to the context-aware services. The propose is validated through two scenarios: the first is a mashup that shows the availability of wireless networks in a particular location, and the second is a prototype of a connection manager to attend user´s preferences. In addition, two evaluations are accomplished on the impact by the use of context information over handovers. Thus, an NGN testbed is deployed with Mobile IP protocol

Em NGN (Next Generation Networks), os usuários podem se conectar em diferentes tecnologias de rede e desejam, além de uma comunicação transparente, novos serviços personalizados. Neste sentido, este trabalho explora informações de contexto em NGN. O principal objetivo é capturar as informações de contexto envolvidas no momento da utilização da rede sem fio, na escolha do novo ponto de acesso e no procedimento do handover. Este contexto capturado é aplicado para serviços cientes de contexto. A proposta é validada por meio de dois cenários, o primeiro é um mashup que exibe as redes sem fio disponíveis de um determinado local e o segundo um protótipo gerenciador de conexões para atender as preferências do usuário. Adicionalmente, são realizadas duas avaliações do impacto do uso de contexto em handovers. Para tanto, foi implantado um testbed NGN com o protocolo Mobile IP / In the NGN (Next Generation Networks) users can connect their Internet devices to different network technologies. In addition to a seamless communication, users desire new and personalized services. In this sense, this thesis exploits the context-aware information in NGN environments. The main propose is to capture the context information about the time involved by the use of wireless link for selecting the target access point and on the handover procedure. This context information is applied to the context-aware services. The propose is validated through two scenarios: the first is a mashup that shows the availability of wireless networks in a particular location, and the second is a prototype of a connection manager to attend user´s preferences. In addition, two evaluations are accomplished on the impact by the use of context information over handovers. Thus, an NGN testbed is deployed with Mobile IP protocol

Last mile transportation is the most problematic phase of transportation needing additional research and effort. Longer waits or search times, lack of navigational directions and real-time information are some of the common problems associated with last mile transportation. Inefficient last mile transportation has an impact on the environment, fuel consumption, user satisfaction and business opportunities. Last mile problems exist in several transportation domains, such as: the landing of airplanes, docking of ships, parking of vehicles, attended home deliveries, etc. While there are dedicated inter-connected decision support systems available for ships and aircraft, similar systems are not widely utilized in parking or attended handover domains. Therefore, the scope of this thesis covers last mile transportation problems in parking and attended handover domains. One problem area for parking and attended handovers is due to lack of real-time information to the driver or consumer. The second problem area is dynamic scheduling where the handover vehicle must traverse additional distance to multiple handover locations due to lack of optimized routes. Similarly, during parking, lack of navigational directions to an empty parking space can lead to increased fuel consumption and CO2 emissions. Therefore, aim of this thesis is to design and develop decision support systems for last mile transportation problems by holistically addressing real time customer communication and dynamic scheduling problem areas. The problem areas discussed in this thesis consists of persistent issues even though they were widely discussed in the literature. In order to investigate the problem areas, microdata analysis approach was implemented in the thesis. The phases involved in Microdata analysis are: data collection, data processing, data storage, data analysis and decision-making. Other similar research domains, such as: computer science or statistics also involve phases such as data collection, processing, storage and analysis. These research domains also work in the fields of decision support systems or knowledge creation. However, knowledge creation or decision support systems is not a mandatory phase in these research domains, unlike Microdata analysis. Three papers are presented in this thesis, with two papers focusing on parking domains, while the third paper focuses on attended handover domains. The first paper identifies available smart parking tools, applications and discusses their uses and drawbacks in relation to open parking lots. The usage of cameras in identifying parking occupancy was recognized as one of the suitable tools in this paper. The second paper uses a thermal camera to collect the parking lot data, while deep learning methodologies were used to identify parking occupancy detection. Multiple deep learning networks were evaluated for identifying parking spaces and one method was considered suitable for acquiring real time parking occupancy. The acquired parking occupancy information can be communicated to the user to address real-time customer communication problems. However, the decision support system (DSS) to communicate parking occupancy information still needs to be developed. The third paper focuses on the attended handovers domain where a decision support system was reported which addresses real-time customer communication and dynamic scheduling problems holistically. Based on a survey, customers accepted the use of mobile devices for enabling a real-time information flow for improving customer satisfaction. A pilot test on vehicle routing was performed where the decision support system reduced the vehicle routing distance compared to the route taken by the driver. The three papers work in developing decision support systems for addressing major last mile transportation problems in parking and attended handover domains, thus improving customer satisfaction, and business opportunities, and reducing fuel costs, and pollution.

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No / In the telecommunication networks the introduction of Next Generation Wireless Networks (NGWN) has been described as the most significant change in wireless communication. The convergence of different access networks in NGWN allows generalized mobility, consistency and ubiquitous provision of services to mobile users. The general target of NGWN is to transport different types of information like voice, data, and other media like video in packets form like IP. The NGWNs offer significant savings in costs to the operators along with new and interesting services to the consumers. Major challenges in NGWN are efficient resource utilization, maintaining service quality, reliability and the security. This paper proposes a solution for seamless load aware Radio Access Technology (RAT) selection based on interworking of different RATs in NGWN. In this paper novel load balancing algorithms have been proposed which have been simulated on the target network architecture for TCP data services. The IEEE 802.21 Media Independent Handover (MIH) is utilized in load balancing specifically for mobility management, which enable low handover latency by reducing the target network detection time. The proposed method considers the network type, signal strength, data rate and network load as primary decision parameters for RAT selection process and consists of two different algorithms, one located in the mobile terminal and the other at the network side. The network architecture, the proposed load balancing framework and RAT selection algorithms were simulated using NS2. Different attributes like load distribution in the wireless networks and average throughput to evaluate the effects of load balancing in considered scenarios.

No / The ever increasing user QoS demands and emergence of new user applications make job of network operators and manufacturers more challenging for efficiently optimisation and managing radio resources in radio the radio resources pools of different wireless networks. A group of strategies or mechanisms which are collectively responsible for efficient utilisation of radio resources available within the Radio Access Technologies (RAT) are termed as Radio Resource Management (RRM). The traditional RRM strategies are implemented independently in each RAT, as each RRM strategy considers attributes of a particular access technology. Therefore traditional RRM strategies are not suitable for heterogeneous wireless networks. Common Radio Resource Management (CRRM) or joint radio resource management (JRRM) strategies are proposed for coordinating radio resource management between multiple RATs in an improved manner. In this paper a fuzzy algorithm based CRRM strategy is presented to efficiently utilise the available radio resources in heterogeneous wireless networks. The proposed CRRM strategy balances the load in heterogeneous wireless networks and avoids the unwanted congestion situation. The results such as load distribution, packet drop rate and average throughput at mobile nodes are used to demonstrate the benefits of load balancing in heterogeneous wireless networks using proposed strategy.

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