Developing route optimization-based PMIPv6 testbed for reliable packet transmission.

Proxy Mobile IPv6 (PMIPv6) allows a mobile node to communicate directly to its peers while changing the currently used IP address. This mode of operation is called route optimization (RO). In the RO process, the peer node learns a binding between the home address and its current temporary care-of-address. Many schemes have been proposed to support RO in PMIPv6. However, these schemes do not consider the out-of-sequence problem, which may happen between the existing path and the newly established RO path. In this paper, we propose a scheme to solve the out-of-sequence problem with low cost. In our scheme, we use the additional packet sequence number and the time information when the problem occurs. We then run experiments on a reliable packet transmission (RPT) laboratory testbed to evaluate the performance of the proposed scheme, and compare it with the well-known RO-supported PMIPv6 and the out-of-sequence time period scheme. The experimental results show that for most of the cases, our proposed scheme guarantees RPT by preventing the out-of-sequence problem.N/

Simultaneous multi-access in heterogeneous mobile networks

The exponential growth of the number of multihomed mobile devices is changing the way how we connect to the Internet. Unfortunately, it is not yet easily possible to a multihomed device to be simultaneously connected to the network through multiple links. This work enhances the network access of multihomed devices. This enhancement is achieved by using simultaneously all of the mobile devices interfaces, and by individually routing each data flow through the most adequate technology. The proposed solution is only deployed at the network core and it does not depend on the mobile devices, i.e., it’s transparent to the mobile devices. This work gives the necessary tools to reuse the already deployed technologies like WiFi or 3G/LTE. Moreover, it is also possible to extend the network by using femtocells which support multi access technologies. This work is also integrated with IEEE 802.21 standard to improve the handover mechanisms in the network. Additionally, we also propose an integration with a broker that can manage all the data flows individually. The proposed solution improves the quality of service of the users while not overloading the operator infrastructure. Evaluation results, obtained from the developed prototype, evidence that the overhead for using the proposed solution is very small when compared to the advantages.O crescimento exponencial do número de equipamentos móveis com múltiplas tecnologias de acesso à rede está a mudar a maneira como nos ligamos à Internet. Infelizmente, ainda não é possível usar simultaneamente todas as interfaces de rede de um equipamento móvel. Este trabalho melhora o acesso à rede a partir de dispositivos móveis com múltiplas interfaces de rede. Para alcançar esta melhoria todas as interfaces de rede dos dispositivos móveis podem ser usadas simultaneamente, e os fluxos de tráfego são encaminhados individualmente através da tecnologia mais conveniente. A solução proposta apenas é instalada na rede core, ou seja, é transparente para os equipamentos móveis. Este trabalho desenvolveu as ferramentas necessárias para reutilizar as tecnologias existentes que já estão disponíveis em larga escala, como o WiFi ou o 3G/LTE. É também possível usar femto-­células com suporte a múltiplas tecnologias de acesso para expandir mais rapidamente a rede. Este trabalho criou também uma integração com a norma IEEE 802.21 para melhorar os processos de handover. Adicionalmente propomos a integração com um broker externo para uma melhor gestão dos fluxos de tráfego. A solução proposta melhora a qualidade de serviço dos utilizadores sem sobrecarregar a infra-­estrutura do operador. Os resultados obtidos a partir dos testes realizados ao protótipo desenvolvido mostram que o impacto na performance ao usar esta solução é extremamente reduzido quando comparado com as suas vantagens

Cognitive radio network in vehicular ad hoc network (VANET): a survey

Cognitive radio network and vehicular ad hoc network (VANET) are recent emerging concepts in wireless networking. Cognitive radio network obtains knowledge of its operational geographical environment to manage sharing of spectrum between primary and secondary users, while VANET shares emergency safety messages among vehicles to ensure safety of users on the road. Cognitive radio network is employed in VANET to ensure the efficient use of spectrum, as well as to support VANET’s deployment. Random increase and decrease of spectrum users, unpredictable nature of VANET, high mobility, varying interference, security, packet scheduling, and priority assignment are the challenges encountered in a typical cognitive VANET environment. This paper provides survey and critical analysis on different challenges of cognitive radio VANET, with discussion on the open issues, challenges, and performance metrics for different cognitive radio VANET applications

Cognitive radio network in vehicular ad hoc network (VANET): a survey

Cognitive radio network and vehicular ad hoc network (VANET) are recent emerging concepts in wireless networking. Cognitive radio network obtains knowledge of its operational geographical environment to manage sharing of spectrum between primary and secondary users, while VANET shares emergency safety messages among vehicles to ensure safety of users on the road. Cognitive radio network is employed in VANET to ensure the efficient use of spectrum, as well as to support VANET’s deployment. Random increase and decrease of spectrum users, unpredictable nature of VANET, high mobility, varying interference, security, packet scheduling, and priority assignment are the challenges encountered in a typical cognitive VANET environment. This paper provides survey and critical analysis on different challenges of cognitive radio VANET, with discussion on the open issues, challenges, and performance metrics for different cognitive radio VANET applications

Cognitive radio network in vehicular ad hoc network (VANET): a survey

Cognitive radio network and vehicular ad hoc network (VANET) are recent emerging concepts in wireless networking. Cognitive radio network obtains knowledge of its operational geographical environment to manage sharing of spectrum between primary and secondary users, while VANET shares emergency safety messages among vehicles to ensure safety of users on the road. Cognitive radio network is employed in VANET to ensure the efficient use of spectrum, as well as to support VANET’s deployment. Random increase and decrease of spectrum users, unpredictable nature of VANET, high mobility, varying interference, security, packet scheduling, and priority assignment are the challenges encountered in a typical cognitive VANET environment. This paper provides survey and critical analysis on different challenges of cognitive radio VANET, with discussion on the open issues, challenges, and performance metrics for different cognitive radio VANET applications

Analysis, design and experimental evaluation of connectivity management in heterogeneous wireless environments

Mención Internacional en el título de doctorThe future of network communications is mobile as many more users demand for ubiquitous connectivity. Wireless has become the primary access technology or even the only one, leading to an explosion in traffic demand. This challenges network providers to manage and configure new requirements without incrementing costs in the same amount. In addition to the growth in the use of mobile devices, there is a need to operate simultaneously different access technologies. As well, the great diversity of applications and the capabilities of mobile terminals makes possible for us to live in a hyper-connected world and offers new scenarios. This heterogeneity poses great challenges that need to be addressed to offer better performance and seamless experience to the final user. We need to orchestrate solutions to increase flexibility and empower interoperability. Connectivity management is handled from different angles. In the network stack, mobility is more easily handled by IP mobility protocols, since IP is the common layer between the different access technologies and the application diversity. From the end-user perspective, the connection manager is in charge of handling connectivity issues in mobile devices, but it is an unstandardized entity so its performance is heavily implementation-dependent. In this thesis we explore connectivity management from different angles. We study mobility protocols as they are part of our proposed solutions. In most of the cases we include an experimental evaluation of performance with 3G and IEEE 802.11 as the main technologies. We consider heterogeneous scenarios, with several access technologies where mobile devices have also several network interfaces. We evaluate how connectivity is handled as well as its influence in a handover. Based on the analysis of real traces from a cellular network, we confirm the suitability of more efficient mobility management. Moreover, we propose and evaluate three different solutions for providing mobility support in three different heterogeneous scenarios. We perform an experimental evaluation of a vehicular route optimization for network mobility, reporting on the challenges and lessons learned in such a complicated networking environment. We propose an architecture for supporting mobility and enhance handover in a passive optical network deployment. In addition, we design and deploy a mechanism for mobility management based on software-defined networking.Programa Oficial de Doctorado en Ingeniería TelemáticaPresidente: Arturo Azcorra Saloña.- Secretario: Ramón Agüero Calvo.- Vocal: Daniel Nunes Coruj

Project Final Report – FREEDOM ICT-248891

This document is the final publishable summary report of the objective and work carried out within the European Project FREEDOM, ICT-248891.This document is the final publishable summary report of the objective and work carried out within the European Project FREEDOM, ICT-248891.Preprin

Distribuição de vídeo para grupos de utilizadores em redes móveis heterogéneas19

The evolutions veri ed in mobile devices capabilities (storage capacity, screen resolution, processor, etc.) over the last years led to a signi cant change in mobile user behavior, with the consumption and creation of multimedia content becoming more common, in particular video tra c. Consequently, mobile operator networks, despite being the target of architectural evolutions and improvements over several parameters (such as capacity, transmission and reception performance, amongst others), also increasingly become more frequently challenged by performance aspects associated to the nature of video tra c, whether by the demanding requirements associated to that service, or by its volume increase in such networks. This Thesis proposes modi cations to the mobile architecture towards a more e cient video broadcasting, de ning and developing mechanisms applicable to the network, or to the mobile terminal. Particularly, heterogeneous networks multicast IP mobility supported scenarios are focused, emphasizing their application over di erent access technologies. The suggested changes are applicable to mobile or static user scenarios, whether it performs the role of receiver or source of the video tra c. Similarly, the de ned mechanisms propose solutions targeting operators with di erent video broadcasting goals, or whose networks have di erent characteristics. The pursued methodology combined an experimental evaluation executed over physical testbeds, with the mathematical evaluation using network simulation, allowing the veri cation of its impact on the optimization of video reception in mobile terminalsA evolução veri cada nas características dos dispositivos moveis (capacidade de armazenamento, resolução do ecrã, processador, etc.) durante os últimos anos levou a uma alteração signi cativa nos comportamentos dos utilizadores, sendo agora comum o consumo e produção de conteúdos multimédia envolvendo terminais móveis, em particular o tráfego vídeo. Consequentemente, as redes de operador móvel, embora tendo também sido alvo constante de evoluções arquitecturais e melhorias em vários parâmetros (tais como capacidade, ritmo de transmissão/recepção, entre outros), vêemse cada vez mais frequentemente desa adas por aspectos de desempenho associados à natureza do tráfego de vídeo, seja pela exigência de requisitos associados a esse serviço, quer pelo aumento do volume do mesmo nesse tipo de redes. Esta Tese propôe alterações à arquitetura móvel para a disseminação de vídeo mais e ciente, de nindo e desenvolvendo mecanismos aplicáveis à rede, ou ao utilizador móvel. Em particular, são focados cenários suportados por IP multicast em redes móveis heterogéneas, isto é, com ênfase na aplicação destes mecanismos sobre diferentes tecnologias de acesso. As alterações sugeridas aplicam-se a cenários de utilizador estático ou móvel, sendo este a fonte ou receptor do tráfego vídeo. Da mesma forma, são propostas soluções tendo em vista operadores com diferentes objectivos de disseminação de vídeo, ou cujas redes têm diferentes características. A metodologia utilizada combinou a avaliação experimental em testbeds físicas com a avaliação matemática em simulações de redes, e permitiu veri car o impacto sobre a optimização da recepção de vídeo em terminais móveisPrograma Doutoral em Telecomunicaçõe

Utilização de diferentes tecnologias em redes de veículos

Mestrado em Engenharia Eletrónica e TelecomunicaçõesCom o surgimento de notícias relacionadas com carros autónomos, torna-se óbvio que as Redes Veiculares vão ter um papel chave num futuro muito próximo. Para além disso, estas redes podem ser utilizadas para fornecer serviços de entretenimento para os passageiros dos veículos (Internet sem recurso a tecnologia celular). Os maiores desa os relacionados com este tipo de redes estão associados com a extrema mobilidade que os nós têm, as constantes quebras de ligação e as perdas de tráfego devido à degradação do sinal das redes wireless, que num ambiente repleto de obstáctulos como é uma cidade, são uma constate. Outro desa o/oportunidade é possibilitar que este tipo de redes tirem partido de todos os recursos disponíveis, isto é, como hoje em dia as cidades estão repletas de redes wireless, os nós têm de ter inteligência de selecionar a/as rede/redes que fazem sentido, e encaminhar o tráfego através dessas mesmas redes, tendo em conta a carga de cada rede. O objetivo desta dissertação vai ser resolver/minorar os problemas acima descritos. Em primeira instância, e com o objetivo de aumentar a e ciência de uma VANET já desenvolvida no nosso grupo, foi criado um gestor de conectividade do tráfego de uplink, que é capaz de diferenciar o tráfego, e depois dividido através das redes de acesso, tendo em conta a carga de cada uma. Isto é suportado quer quando o carro tem acesso direto à infraestrutura ou quando tem acesso indireto (quando existe outro carro a agir com midle-man). Para melhorar a performance da VANET em momentos de quebra de ligação, foi criada uma mensagem de perda de ligação que, quando o sinal da ligação se aproxima para níveis considerados maus informa a unidade responsável por dividir o tráfego pelas redes de acesso, que determinada ligação é má, e não é para ser usada. Por m, para resolver o problema das perdas relacionadas com as ligações sem os, optou-se por utilizar o network coding. O maior desa o foi tornar a utilização do network coding transparente para o protocolo de mobilidade. Por outras palavras, criar um programa que, de forma independente, trata de todos os aspetos relacionado com a codi cação/descodi cação e deixar para o protocolo de mobilidade os aspetos relacionados com a gestão da mobilidade. Para validar todo o trabalho feito, foram realizados testes de laboratório (gestor de ligações de uplink e network coding) e testes de reais (mensagem de perda de ligação). Os testes de laboratório mostraram que o tráfego de uplink é dividido com sucesso, e que o gestor de conetividade envia o tráfego para as redes de acesso tendo em conta a carga de cada uma, quer em single, quer em multi-hop. Relativamente aos testes reais, foi demonstrado que a mensagem de perda de ligação permite diminuir perdas associadas ao processe de handovers. Por m, relativamente ao network coding foi possível concluir que este permite recuperar de perda de pacotes. Além disto, foi demostrado que esta implementação suporta mobilidade e multihoming quer em single quer em multi-hop.ehicular networks will have a key role in a near future. Furthermore, these networks can be utilized to provide entertainment services (Internet) to the car passengers. The greater challenges related with this kind of networks are associated with the high mobility that the nodes have, the constant drop of connectivity and to the tra c losses due the signal degradation of the wireless networks, due to the huge amount of obstacles presented in the city. Another challenge/opportunity is the possibility of these networks to take advantage of all the available resources available. Nowadays the cities have networks available almost everywhere, the nodes must have intelligence to select the network/networks that make sense, and manage the routing through those networks, taking into account the load of each access network. The objective of this dissertation will be to solve/reduce the problems described above. At the rst instance, the objective is to improve the vehicular network already developed in our group, that already has a multihoming framework that allows the downlink tra c to be divided through the available networks, in a way that optimizes the network performance. In order to also provide multihoming in uplink, in this dissertation it was developed an uplink connection manager that can di erentiate the tra c and route that tra c through di erent access networks at the same time, taking into account the load of each network. This can be done in single and multi-hop. In order to improve the multihoming framework, it was developed a message that informs the entity responsible for dividing the tra c that the connections with bad signal quality should not be used to route tra c. This will allow that entity to route the tra c through the other available networks with a good signal quality, avoiding packet losses that would occur due bad signal quality and connection losses. Finally, in order to recover from packet losses due to bad network signal quality, it was used network coding. The greatest challenge was to create a network coding approach, that was transparent to the mobility protocol, that, in an independent way manages all the aspects related to the encoding/ decoding and leave to the mobility protocol the management of all the mobility related aspects. It were also developed two algorithms that nd the con gurations to the encoding process. One of the algorithms will try to ensure the maximum packet loss recovery, and the other will try to assure a packet loss lower than a threshold, with the minimum overhead possible. In order to evaluate all the work done in this dissertation, it were performed laboratory tests (uplink manager and network coding) and real world tests (disconnect message). These tests show that the uplink manager is able to di erentiate tra c, and route through di erent access networks at the same time, taking into account the load of each network (in single and multi-hop). The tests related with the disconnect message show that this message removes the packet loss that would normally occur in the handover mechanisms. Finally, the network coding tests show that the network coding can be used to recover from packet loss, even in a vehicular network with multihoming and in single/multi-hop. Moreover, it was possible to conclude that the two developed algorithms accomplish all the proposed objectives

Contributions to Vehicular Communications Systems and Schemes

La dernière décennie a marqué une grande hausse des applications véhiculaires comme une nouvelle source de revenus et un facteur de distinction dans l'industrie des véhicules. Ces applications véhiculaires sont classées en deux groupes : les applications de sécurité et les applications d'info divertissement. Le premier groupe inclue le changement intelligent de voie, l'avertissement de dangers de routes et la prévention coopérative de collision qui comprend la vidéo sur demande (VoD), la diffusion en direct, la diffusion de météo et de nouvelles et les jeux interactifs. Cependant, Il est à noter que d'une part, les applications véhiculaires d'info divertissement nécessitent une bande passante élevée et une latence relativement faible ; D'autre part, les applications de sécurité requièrent exigent un délai de bout en bout très bas et un canal de communication fiable pour la livraison des messages d'urgence. Pour satisfaire le besoin en applications efficaces, les fabricants de véhicules ainsi que la communauté académique ont introduit plusieurs applications à l’intérieur de véhicule et entre véhicule et véhicule (V2V). Sauf que, l'infrastructure du réseau sans fil n'a pas été conçue pour gérer les applications de véhicules, en raison de la haute mobilité des véhicules, de l'imprévisibilité du comportement des conducteurs et des modèles de trafic dynamiques. La relève est l'un des principaux défis des réseaux de véhicules, car la haute mobilité exige au réseau sans fil de faire la relève en un très court temps. De plus, l'imprévisibilité du comportement du conducteur cause l'échec des protocoles proactifs traditionnels de relève, car la prédiction du prochain routeur peut changer en fonction de la décision du conducteur. Aussi, le réseau de véhicules peut subir une mauvaise qualité de service dans les régions de relève en raison d'obstacles naturels, de véhicules de grande taille ou de mauvaises conditions météorologiques. Cette thèse se concentre sur la relève dans l'environnement des véhicules et son effet sur les applications véhiculaires. Nous proposons des solutions pratiques pour les réseaux actuellement déployés, principalement les réseaux LTE, l'infrastructure véhicule à véhicule (V2V) ainsi que les outils efficaces d’émulateurs de relèves dans les réseaux véhiculaires.----------ABSTRACT: The last decade marked the rise of vehicular applications as a new source of revenue and a key differentiator in the vehicular industry. Vehicular Applications are classified into safety and infotainment applications. The former include smart lane change, road hazard warning, and cooperative collision avoidance; however, the latter include Video on Demand (VoD), live streaming, weather and news broadcast, and interactive games. On one hand, infotainment vehicular applications require high bandwidth and relatively low latency; on the other hand, safety applications requires a very low end to end delay and a reliable communication channel to deliver emergency messages. To satisfy the thirst for practical applications, vehicle manufacturers along with research institutes introduced several in-vehicle and Vehicle to Vehicle (V2V) applications. However, the wireless network infrastructure was not designed to handle vehicular applications, due to the high mobility of vehicles, unpredictability of drivers’ behavior, and dynamic traffic patterns. Handoff is one of the main challenges of vehicular networks since the high mobility puts pressure on the wireless network to finish the handoff within a short period. Moreover, the unpredictability of driver behavior causes the traditional proactive handoff protocols to fail, since the prediction of the next router may change based on the driver’s decision. Moreover, the vehicular network may suffer from bad Quality of Service (QoS) in the regions of handoff due to natural obstacles, large vehicles, or weather conditions. This thesis focuses on the handoff on the vehicular environment and its effect on the vehicular applications. We consider practical solutions for the currently deployed networks mainly Long Term Evolution (LTE) networks, the Vehicle to Vehicle (V2V) infrastructure, and the tools that can be used effectively to emulate handoff on the vehicular networks