Mobile Networks

The growth in the use of mobile networks has come mainly with the third generation systems and voice traffic. With the current third generation and the arrival of the 4G, the number of mobile users in the world will exceed the number of landlines users. Audio and video streaming have had a significant increase, parallel to the requirements of bandwidth and quality of service demanded by those applications. Mobile networks require that the applications and protocols that have worked successfully in fixed networks can be used with the same level of quality in mobile scenarios. Until the third generation of mobile networks, the need to ensure reliable handovers was still an important issue. On the eve of a new generation of access networks (4G) and increased connectivity between networks of different characteristics commonly called hybrid (satellite, ad-hoc, sensors, wired, WIMAX, LAN, etc.), it is necessary to transfer mechanisms of mobility to future generations of networks. In order to achieve this, it is essential to carry out a comprehensive evaluation of the performance of current protocols and the diverse topologies to suit the new mobility conditions

Resource Allocation for Cellular/WLAN Integrated Networks

The next-generation wireless communications have been envisioned to be supported by heterogeneous networks using various wireless access technologies. The popular cellular networks and wireless local area networks (WLANs) present perfectly complementary characteristics in terms of service capacity, mobility support, and quality-of-service (QoS) provisioning. The cellular/WLAN interworking is thus an effective way to promote the evolution of wireless networks. As an essential aspect of the interworking, resource allocation is vital for efficient utilization of the overall resources. Specially, multi-service provisioning can be enhanced with cellular/WLAN interworking by taking advantage of the complementary network strength and an overlay structure. Call assignment/reassignment strategies and admission control policies are effective resource allocation mechanisms for the cellular/WLAN integrated network. Initially, the incoming calls are distributed to the overlay cell or WLAN according to call assignment strategies, which are enhanced with admission control policies in the target network. Further, call reassignment can be enabled to dynamically transfer the traffic load between the overlay cell and WLAN via vertical handoff. By these means, the multi-service traffic load can be properly shared between the interworked systems. In this thesis, we investigate the load sharing problem for this heterogeneous wireless overlay network. Three load sharing schemes with different call assignment/reassignment strategies and admission control policies are proposed and analyzed. Effective analytical models are developed to evaluate the QoS performance and determine the call admission and assignment parameters. First, an admission control scheme with service-differentiated call assignment is studied to gain insights on the effects of load sharing on interworking effectiveness. Then, the admission scheme is extended by using randomized call assignment to enable distributed implementation. Also, we analyze the impact of user mobility and data traffic variability. Further, an enhanced call assignment strategy is developed to exploit the heavy-tailedness of data call size. Last, the study is extended to a multi-service scenario. The overall resource utilization and QoS satisfaction are improved substantially by taking into account the multi-service traffic characteristics, such as the delay-sensitivity of voice traffic, elasticity and heavy-tailedness of data traffic, and rate-adaptiveness of video streaming traffic

Routing and dimensioning of 3G multi-service networks

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

3G migration in Pakistan

The telecommunication industry in Pakistan has come a long way since the country\u27s independence in 1947. The initial era could be fairly termed as the PTCL (Pakistan Telecommunication Company Limited) monopoly, for it was the sole provider of all telecommunication services across the country. It was not until four decades later that the region embarked into the new world of wireless communication, hence ending the decades old PTCL monopoly. By the end of the late 1990\u27s, government support and international investment in the region opened new doors to innovation and better quality, low cost, healthy competition. Wireless licenses for the private sector in the telecommunication industry triggered a promising chain of events that resulted in a drastic change in the telecommunication infrastructure and service profile. The newly introduced wireless (GSM) technology received enormous support from all stakeholders (consumers, regulatory body, and market) and caused a vital boost in Pakistan\u27s economy. Numerous tangential elements had triggered this vital move in the history of telecommunications in Pakistan. Entrepreneurs intended to test the idea of global joint ventures in the East and hence the idea of international business became a reality. The technology had proven to be a great success in the West, while Pakistan\u27s telecom consumer had lived under the shadow of PTCL dominance for decades and needed more flexibility. At last the world was moving from wired to wireless! Analysts termed this move as the beginning of a new era. The investors, telecommunication businesses, and Pakistani treasury prospered. It was a win-win situation for all involved. The learning curve was steep for both operators and consumers but certainly improved over time. In essence, the principle of deploying the right technology in the right market at the right time led to this remarkable success. The industry today stands on the brink of a similar crossroads via transition from second generation to something beyond. With the partial success of 3G in Europe and the USA, the government has announced the release of three 3G licenses by mid 2009. This decision is not yet fully supported by all but still initiated parallel efforts by the operators and the vendors to integrate this next move into their existing infrastructure

Multicast Scheduling and Resource Allocation Algorithms for OFDMA-Based Systems: A Survey

Multicasting is emerging as an enabling technology for multimedia transmissions over wireless networks to support several groups of users with flexible quality of service (QoS)requirements. Although multicast has huge potential to push the limits of next generation communication systems; it is however one of the most challenging issues currently being addressed. In this survey, we explain multicast group formation and various forms of group rate determination approaches. We also provide a systematic review of recent channel-aware multicast scheduling and resource allocation (MSRA) techniques proposed for downlink multicast services in OFDMA based systems. We study these enabling algorithms, evaluate their core characteristics, limitations and classify them using multidimensional matrix. We cohesively review the algorithms in terms of their throughput maximization, fairness considerations, performance complexities, multi-antenna support, optimality and simplifying assumptions. We discuss existing standards employing multicasting and further highlight some potential research opportunities in multicast systems

Redes sem fio de longas distâncias: novas contribuições para a justiça em nível de usuário e para a qualidade de serviços em fluxos de vídeo escalável

Esta tese tem como objetivo a avaliação de desempenho do acesso sem fio à internet para o uso de aplicações web e de vídeo escalável. O texto trata das principais contribuições alcançadas por este trabalho que são: (i) o desenvolvimento de um novo modelo de simulação de uma célula EVDO com o qual avaliamos justiça usando métricas como a vazão e o atraso, sob influência de diferentes cenários de mobilidade. Além disso, propomos uma solução simples para melhorar a justiça entre os usuários deste tipo de rede sem fio; e, (ii) a proposta de modelos matemáticos que nos permitem estudar, sob um novo ponto de vista, o processo aleatório de perda em filas FIFO/Droptail. Com base os resultados obtidos, propomos uma nova técnica fim-a-fim de transmissão de fluxos de vídeo escalável. Mostramos com essa técnica que, mesmo sem o emprego de complexos algoritmos de escalonamento e descarte nos roteadores, é possível priorizar os pacotes mais importantes para a qualidade do vídeo sem o uso de métodos tradicionais de priorização. Através de modelos de simulação desenvolvidos durante esta tese, avaliamos o ganho de qualidade atingido quando nossa técnica é usada, considerando perfis de vídeos bem conhecidos

Context-Aware Voip congestion control service

Published in The African Journal of Information and Communication, Issue no 11 2010/2011IP networks can have difficulty coping with delay-sensitive VoIP traffics during emergency situations caused by fires and related disasters. During emergencies there is a huge increase in voice and video traffic, causing a huge strain on the network. The strain on the network is as a result of both essential and non-essential traffic. In such crisis situations, calls originating from or destined for rescue personnel, such as doctors and police, are considered essential. Any other calls from eyewitnesses and the public are considered non-essential, since they degrade the quality of service for the emergency response teams by consuming the scarce network resources. Providing the rescue team with the quality of service that they require necessitates network access restriction for non-essential traffic. In this paper, the authors present a voice and video service that uses Context-Awareness and Semantic Web technologies to restrict network access to privileged users during crisis situations. The service monitors the network for crisis conditions, enables the network to respond appropriately when a crisis occurs, detects the end of the crisis and reverts to its default state.IP networks can have difficulty coping with delay-sensitive VoIP traffics during emergency situations caused by fires and related disasters. During emergencies there is a huge increase in voice and video traffic, causing a huge strain on the network. The strain on the network is as a result of both essential and non-essential traffic. In such crisis situations, calls originating from or destined for rescue personnel, such as doctors and police, are considered essential. Any other calls from eyewitnesses and the public are considered non-essential, since they degrade the quality of service for the emergency response teams by consuming the scarce network resources. Providing the rescue team with the quality of service that they require necessitates network access restriction for non-essential traffic. In this paper, the authors present a voice and video service that uses Context-Awareness and Semantic Web technologies to restrict network access to privileged users during crisis situations. The service monitors the network for crisis conditions, enables the network to respond appropriately when a crisis occurs, detects the end of the crisis and reverts to its default state

Context-aware VoIP congestion control service

IP networks can have difficulty coping with delay-sensitive VoIP traffics during emergency situations caused by fires and related disasters. During emergencies there is a huge increase in voice and video traffic, causing a huge strain on the network. The strain on the network is as a result of both essential and non-essential traffic. In such crisis situations, calls originating from or destined for rescue personnel, such as doctors and police, are considered essential. Any other calls from eyewitnesses and the public are considered non-essential, since they degrade the quality of service for the emergency response teams by consuming the scarce network resources. Providing the rescue team with the quality of service that they require necessitates network access restriction for non-essential traffic. In this paper, the authors present a voice and video service that uses Context-Awareness and Semantic Web technologies to restrict network access to privileged users during crisis situations. The service monitors the network for crisis conditions, enables the network to respond appropriately when a crisis occurs, detects the end of the crisis and reverts to its default state

The use of BGAN to implement a robust tsunami early warning system

A tsunami is a series of waves created when a body of water, such as an ocean, is rapidly displaced probably by an oceanic earthquake. The effects of a tsunami for the population can be devastating due to the immense volumes of water and energy involved.The EU-funded Distant Early Warning System (DEWS) project is currently implementing a reference model for a national and regional warning dissemination system of possible hazards or disasters, especially in the prevention of tsunamis. In DEWS several universities and companies are participating specially coming from Europe and from the three countries of interest Sri Lanka, Indonesia and Thailand.The Department of Communications and Networking of the Helsinki University of Technology (TKK) is a consortium member of the DEWS project working on the development of the communications architecture between the different Emergency Centres, first responders and general public.In this thesis report we present the implementation of a backup satellite communications system between DEWS centres and governmental authorities in order to enable the warning dissemination in case the terrestrial communication structures are disrupted due to the hazard effects.The backup communications structure would employ the BGAN Inmarsat service for the date transmission. BGAN ensures the coverage in almost global earth area and support mobility on its terminals, offering adequate characteristics for an emergency communications system. To that end, we design and describe this communications architecture and discuss its performance in the possible scenarios based on simulations

Review to the implementation of IPTV service over wireless and mobiles networks with Quality of Service (QoS)

In the Internet Protocol Television (IPTV) the quality of content delivered to users is affected by different parameters of network performance that must be secured at their minimum values to guarantee the quality perceived by users. The IPTV service deployment on wireless and mobile networks has been facing serious challenges due to limited bandwidth, low reliability and the quality of wireless communication links and user mobility. However, the latest broadband wireless technologies are emerging as suitable networks for the deployment of this service since they are all-IP architectures capabilities to provide end to-end Quality of Service (QoS) and increase the access speed. So, in this paper, we review the work that has been made for the IPTV implementation over wireless and mobile networks with QoS.En IPTV (Internet Protocol Television) la calidad de los contenidos entregados a los usuarios se ve afectada por diferentes parámetros de desempeño de la red que deben ser asegurados en sus valores mínimos para garantizar la calidad percibida por los usuarios. El despliegue del servicio de IPTV sobre redes inalámbricas y móviles ha enfrentado serios desafíos debido a las limitaciones de ancho de banda, a la baja fabilidad y calidad de los enlaces de comunicaciones inalámbricos y a la movilidad de los terminales. Sin embargo, las últimas tecnologías inalámbricas de banda ancha se perflan como redes idóneas para el despliegue de este servicio toda vez que son arquitecturas completamente IP (all-IP) con capacidades de ofrecer Calidad de Servicio (QoS, Quality of Service) de extremo a extremo e incrementan la velocidad de acceso. Por tanto, en este artículo se realiza la revisión de los trabajos que se han realizado para la implementación de la IPTV sobre redes inalámbricas y móviles con QoS