Load Balancing in Tree-based IP Micro-Mobility Domains

Nowadays the penetration of wireless access is continuously increasing. Additionally, the mobile users become more and more dependent on data. The IP-based (Internet Protocol) Internet was designed for data transmission and has become the most ubiquitous wired internetwork. According to these trends the next generation networks (and already 3G networks also include IP-based parts) are designed as a combination of these two types of networks (mobile and IP-based). The Mobile IP protocol handles mobility in the IP layer globally, but it is not well-adopted to local coverage areas. Within such access networks the micro-mobility proposals enhance the performance of Mobile IP. In this paper we propose a solution for improving the performance of tree-based micro-mobility protocols by rearranging their capacity using additional links. Based on analytical considerations we obtain a formula to determine the optimal link size in particular cases. The method is also examined with our simulation testbed, the results show improvement in the performance of the domain

Future Trends and Challenges for Mobile and Convergent Networks

Some traffic characteristics like real-time, location-based, and community-inspired, as well as the exponential increase on the data traffic in mobile networks, are challenging the academia and standardization communities to manage these networks in completely novel and intelligent ways, otherwise, current network infrastructures can not offer a connection service with an acceptable quality for both emergent traffic demand and application requisites. In this way, a very relevant research problem that needs to be addressed is how a heterogeneous wireless access infrastructure should be controlled to offer a network access with a proper level of quality for diverse flows ending at multi-mode devices in mobile scenarios. The current chapter reviews recent research and standardization work developed under the most used wireless access technologies and mobile access proposals. It comprehensively outlines the impact on the deployment of those technologies in future networking environments, not only on the network performance but also in how the most important requirements of several relevant players, such as, content providers, network operators, and users/terminals can be addressed. Finally, the chapter concludes referring the most notable aspects in how the environment of future networks are expected to evolve like technology convergence, service convergence, terminal convergence, market convergence, environmental awareness, energy-efficiency, self-organized and intelligent infrastructure, as well as the most important functional requisites to be addressed through that infrastructure such as flow mobility, data offloading, load balancing and vertical multihoming.Comment: In book 4G & Beyond: The Convergence of Networks, Devices and Services, Nova Science Publishers, 201

Inteligência nas decisões de mobilidade

Mestrado em Engenharia Electrónica e TelecomunicaçõesActualmente existe uma vasta gama de tecnologias de acesso sem fios como Wi-Fi, GPRS, UMTS, HSDPA and WiMAX. No futuro estas diferentes tecnologias complementar-se-ão convergindo numa infra-estrutura heterogénea capaz de fornecer um melhor serviço aos utilizadores, 4G. A evolução dos terminais móveis também permitirá que estes se liguem simultaneamente às redes de acesso. Assim, o conceito existente de “always connected” dará lugar a um novo paradigma, “always best connected”, que basicamente consiste em que o terminal esteja ligado às redes de acesso mais apropriadas num determinado instante e para serviços específicos. Devido ao aumento da complexidade nas decisões de handover das redes de próxima geração, o objectivo desta dissertação consiste no desenvolvimento de uma arquitectura de suporte a mobilidade inteligente. Este mecanismo deve, dependendo do cenário e do contexto, decidir a melhor distribuição dos serviços dos utilizadores pelas diferentes redes de acesso disponíveis. Para implementá-lo, foi usada uma abordagem simples baseada num protocolo responsável pela troca da informação necessária entre os pontos de acesso, terminais móveis e o elemento inteligente. Este último deverá então, através de informação actualizada, decidir a melhor rede de acesso para cada um dos terminais. De forma a simular a resposta do mecanismo perante várias situações, diferentes cenários foram criados para avaliar o desempenho da rede. Da avaliação dos resultados é possível concluir que a introdução de uma entidade inteligente na rede melhora o seu desempenho e experiência do utilizador. ABSTRACT: Currently there is a wide range of wireless access technologies such as Wi-Fi, GPRS, UMTS, HSDPA and WiMAX. In the future these different technologies will converge in a complementary manner forming a heterogeneous infrastructure able to offer a better service to its users, 4G. The evolution of mobile terminals will also allow them to connect simultaneously to several access networks. Thus, the existing concept of “always connected” becomes “always best connected”, consisting in a terminal connected to the most suitable access networks at a certain moment in time and for specific services. Due to the increase of the complexity in handover decisions on the next generation networks, this Thesis has as main goal the development of an architecture capable of supporting intelligent mobility. This mechanism, depending on the scenario and the context, must decide the best distribution of user’s services through the different access networks. To implement it, a simple approach was used based on a protocol responsible for exchanging the necessary information between access points, mobile terminals and the intelligent element. The latter, through updated information, decides the better access network for each terminal. In order to simulate the response of the mechanism in several situations, different scenarios were built to evaluate the performance of the network. From the evaluation it was possible to conclude that the introduction of an intelligent entity in the network improves its performance and the experience of the user

Quality-Oriented Mobility Management for Multimedia Content Delivery to Mobile Users

The heterogeneous wireless networking environment determined by the latest developments in wireless access technologies promises a high level of communication resources for mobile computational devices. Although the communication resources provided, especially referring to bandwidth, enable multimedia streaming to mobile users, maintaining a high user perceived quality is still a challenging task. The main factors which affect quality in multimedia streaming over wireless networks are mainly the error-prone nature of the wireless channels and the user mobility. These factors determine a high level of dynamics of wireless communication resources, namely variations in throughput and packet loss as well as network availability and delays in delivering the data packets. Under these conditions maintaining a high level of quality, as perceived by the user, requires a quality oriented mobility management scheme. Consequently we propose the Smooth Adaptive Soft-Handover Algorithm, a novel quality oriented handover management scheme which unlike other similar solutions, smoothly transfer the data traffic from one network to another using multiple simultaneous connections. To estimate the capacity of each connection the novel Quality of Multimedia Streaming (QMS) metric is proposed. The QMS metric aims at offering maximum flexibility and efficiency allowing the applications to fine tune the behavior of the handover algorithm. The current simulation-based performance evaluation clearly shows the better performance of the proposed Smooth Adaptive Soft-Handover Algorithm as compared with other handover solutions. The evaluation was performed in various scenarios including multiple mobile hosts performing handover simultaneously, wireless networks with variable overlapping areas, and various network congestion levels