Investigation of an intelligent personalised service recommendation system in an IMS based cellular mobile network

Success or failure of future information and communication services in general and mobile communications in particular is greatly dependent on the level of personalisations they can offer. While the provision of anytime, anywhere, anyhow services has been the focus of wireless telecommunications in recent years, personalisation however has gained more and more attention as the unique selling point of mobile devices. Smart phones should be intelligent enough to match user’s unique needs and preferences to provide a truly personalised service tailored for the individual user. In the first part of this thesis, the importance and role of personalisation in future mobile networks is studied. This is followed, by an agent based futuristic user scenario that addresses the provision of rich data services independent of location. Scenario analysis identifies the requirements and challenges to be solved for the realisation of a personalised service. An architecture based on IP Multimedia Subsystem is proposed for mobility and to provide service continuity whilst roaming between two different access standards. Another aspect of personalisation, which is user preference modelling, is investigated in the context of service selection in a multi 3rd party service provider environment. A model is proposed for the automatic acquisition of user preferences to assist in service selection decision-making. User preferences are modelled based on a two-level Bayesian Metanetwork. Personal agents incorporating the proposed model provide answers to preference related queries such as cost, QoS and service provider reputation. This allows users to have their preferences considered automatically

Network-Assisted Handover for Heterogeneous Wireless Networks using IEEE 802.21

The IEEE 802.21 is a standard for enabling handover in heterogeneous wireless networks. Published in January 2009, it defines protocols and messages for mobile-to-node and node-to-node communication in a technology-neutral and flexible manner. The need arises because of the widespread diffusion of different technologies for wireless communications (e.g., WiFi, WiMAX, LTE) coexisting in the same geographical area. Even though the number of multi-radio multi-technology mobile devices is increasing significantly, there are no open solutions in the market to enable efficient inter-technology handover. As is often the case with communication standards, the structure of the required components, the procedures, and the algorithms are left unspecified by the IEEE 802.21 standard so as to promote competion by differentiation of equipment capabilities and services. The contribution of this thesis is two-fold: i) a design and an implemenation of the Media Independent Information Service (MIIS) server; and, ii) a solution to enable network-assisted handover using the IEEE 802.21 standard, aimed at reducing the handover latency and the energy consumption of mobile devices due to scanning. The MIIS server has been fully implemented in C++ under Linux. In order to perform testbed evaluations, all the required components have been implemented, as well, within an open source framework for IEEE 802.21 called ODTONE. Modifications to the latter have been performed for optimization and fine tuning, and for extending those functional modules needed but not fully implemented. For a realistic evaluation, Linux-based embedded COTS devices have been used, equipped with multiple IEEE 802.11a and IEEE 802.11g wireless network interface cards. This has required additional development for kernel/user space binding and hardware control. Testbed results are reported to show the effectiveness of the proposed solution, also proving the MIIS server scalability

Towards Seamless Mobility: An IEEE 802.21 Practical Approach

In the recent years, mobile devices such as cell phones, notebook or ultra mobile computers and videogame consoles are experiencing an impressive evolution in terms of hardware and software possibilities. Elements such a wideband Internet connection allows a broad range of possibilities for creative developers. Many of these possibilities can include applications requiring continuity of service when the user moves form a coverage area to another. Nowadays, mobile devices are equipped with one or more radio interfaces such as GSM, UMTS, WiMax or Wi‐ Fi. Many of these technologies are ready to allow transparent roaming within their own coverage areas, but they are not ready to handle a service transfer between different technologies. In order to find a solution to this issue, the IEEE has developed a standard known as Media Independent Handover (MIH) Services with the aim of easing seamless mobility between these technologies. The present work has been centered in developing a system capable to enable a service of mobility under the terms specified in the stated standard. The development of a platform aiming to provide service continuity is mandatory, being a cross‐layer solution based in elements from link and network layers supplying a transparent roaming mechanism from user’s point of view. Two applications have been implemented in C/C++ language under a Linux environment. One application is designed to work within a mobile device, and the other one in the network access point. The mobile device basically consists in a notebook equipped with two Wi‐Fi interfaces, which is not a common feature in commercial devices, allowing seamless communication transfers aided by the application. Network access points are computers equipped with a Wi‐Fi interface and configured to provide Internet wireless access and services of mobility. In order to test the operation, a test‐bed has been implemented. It consists on a pair of access points connected through a network and placed within partially overlapped coverage areas, and a mobile device, all of them properly set. The mobile detects the networks that are compatible and gets attached to the one that provides better conditions for the demanded service. When the service degrades up to certain level, the mobile transfers the communication to the other access point, which offers better service conditions. Finally, in order to check if the changes have been done properly, the duration of the required actions has been measured, as well as the data that can have been lost or buffered meanwhile. The result is a MIH‐alike system working in a proper way. The discovery and selection of a destination network is correct and is done before the old connection gets too degraded, providing seamless mobility. The measured latencies and packet losses are affordable in terms of MIH protocol, but require future work improvements in terms of network protocols that have not been considered under the scope of this work

Improving and distributing key management on mobile networks

We address the problem of mobile network key management and authentication that negatively affects the handoff performance, adds overhead to the system in terms of key exchange signaling, authentication, and key distribution. We aim to improve the efficiency of the key management subsystem and to reduce investment pressure on core network elements. We address all these problems successfully. Our novel SKC key management mechanism is the best key management mechanism among the ones we found in reducing signaling load from the KD and making the mobility system independent of the AP-KD link delay. It is a significant contribution to the mobile network key management with fast handoffs when separate keys for APs are required and has many useful applications. Our novel receiver and sender ID binding protocol with symmetric keys is new and shows analogy with Identity Based Cryptography. It is a generalization of the identity binding that SKC is using. Furthermore, our distributed AAA architecture with SKC, certificates, and hardware-based security is a disruptive proposal and show how the mobile network KD can be distributed to the edge nodes. Our quantitative analysis and comparison of SKC and LTE key management is new and not seen before. Our research affected the LTE Security standardization and contributes to the research and development of home base stations, community and municipal Wi-Fi access points

Wireless IP network mobility management: advancing from mobile IP to HIP-based network

Wireless networking introduces a whole range of challenges to the traditional TCP/IP network. In particular, IP address the issue of overloading because IP addresses are used as a network locator and an end point identity in the different layers in an OSI model. Even though Mobile IP is widely deployed, it has significant problems relating to performance and security. The Host Identity Protocol (HIP) provides secure mobility management by solving the IP address overloading from another angle. It restructures the TCP/IP model and introduces a new layer and a new namespace. The performance of HIP has proven to be better than Mobile IP and also opens a range of new research opportunities. This dissertation proposes and analyses a new step-stone solution from the Mobile IP-based network into a HIP-based network. The main advantage of this new solution is that much less change is required to the operating system kernel of the end point compared to a full HIP implementation. The new step-stone solution allows Mobile IP to use some HIP features to provide better security and handover performance. This dissertation also proposes several new and novel HIP-based wireless communication network architectures. An HIP-based heterogeneous wireless network architecture and handover scheme has been proposed and analysed. These schemes limit the HIP signalling in the wireless network if no communication to external networks is needed. Beside the network architecture modification, the hybrid Session Initial Protocol (SIP) and HIP-based Voice over IP (VoIP) scheme is proposed and analysed. This novel scheme improves the handover latency and security. This dissertation also proposes and analyses a new and novel extension to HIP, a HIP-based micro-mobility management, micro-HIP (mHIP). mHIP provides a new secure framework for micro-mobility management. It is a more complete HIP-based micro-mobility solution than any other proposed in existing studies. mHIP improves the intra-domain handover performance, the security, and the distribution of load in the intra-domain handover signalling. The new work presented opens up a number of very interesting research opportunities

IP Mobility in Wireless Operator Networks

Wireless network access is gaining increased heterogeneity in terms of the types of IP capable access technologies. The access network heterogeneity is an outcome of incremental and evolutionary approach of building new infrastructure. The recent success of multi-radio terminals drives both building a new infrastructure and implicit deployment of heterogeneous access networks. Typically there is no economical reason to replace the existing infrastructure when building a new one. The gradual migration phase usually takes several years. IP-based mobility across different access networks may involve both horizontal and vertical handovers. Depending on the networking environment, the mobile terminal may be attached to the network through multiple access technologies. Consequently, the terminal may send and receive packets through multiple networks simultaneously. This dissertation addresses the introduction of IP Mobility paradigm into the existing mobile operator network infrastructure that have not originally been designed for multi-access and IP Mobility. We propose a model for the future wireless networking and roaming architecture that does not require revolutionary technology changes and can be deployed without unnecessary complexity. The model proposes a clear separation of operator roles: (i) access operator, (ii) service operator, and (iii) inter-connection and roaming provider. The separation allows each type of an operator to have their own development path and business models without artificial bindings with each other. We also propose minimum requirements for the new model. We present the state of the art of IP Mobility. We also present results of standardization efforts in IP-based wireless architectures. Finally, we present experimentation results of IP-level mobility in various wireless operator deployments.Erilaiset langattomat verkkoyhteydet lisääntyvät Internet-kykyisten teknologioiden muodossa. Lukuisten eri teknologioiden päällekkäinen käyttö johtuu vähitellen ja tarpeen mukaan rakennetusta verkkoinfrastruktuurista. Useita radioteknologioita (kuten WLAN, GSM ja UMTS) sisältävien päätelaitteiden (kuten älypuhelimet ja kannettavat tietokoneet) viimeaikainen kaupallinen menestys edesauttaa uuden verkkoinfrastruktuurin rakentamista, sekä mahdollisesti johtaa verkkoteknologioiden kirjon lisääntymiseen. Olemassa olevaa verkkoinfrastruktuuria ei kaupallisista syistä kannata korvata uudella teknologialla yhdellä kertaa, vaan vaiheittainen siirtymävaihe kestää tyypillisesti useita vuosia. Internet-kykyiset päätelaitteet voivat liikkua joko saman verkkoteknologian sisällä tai eri verkkoteknologioiden välillä. Verkkoympäristöstä riippuen liikkuvat päätelaitteet voivat liittyä verkkoon useiden verkkoyhteyksien kautta. Näin ollen päätelaite voi lähettää ja vastaanottaa tietoliikennepaketteja yhtäaikaisesti lukuisia verkkoja pitkin. Tämä väitöskirja käsittelee Internet-teknologioiden liikkuvuutta ja näiden teknologioiden tuomista olemassa oleviin langattomien verkko-operaattorien verkkoinfrastruktuureihin. Käsiteltäviä verkkoinfrastruktuureita ei alun perin ole suunniteltu Internet-teknologian liikkuvuuden ja monien yhtäaikaisten yhteyksien ehdoilla. Tässä työssä ehdotetaan tulevaisuuden langattomien verkkojen arkkitehtuurimallia ja ratkaisuja verkkovierailujen toteuttamiseksi. Ehdotettu arkkitehtuuri voidaan toteuttaa ilman mittavia teknologisia mullistuksia. Mallin mukaisessa ehdotuksessa verkko-operaattorin roolit jaetaan selkeästi (i) verkko-operaattoriin, (ii) palveluoperaattoriin ja (iii) yhteys- sekä verkkovierailuoperaattoriin. Roolijako mahdollistaa sen, että kukin operaattorityyppi voi kehittyä itsenäisesti, ja että teennäiset verkkoteknologiasidonnaisuudet poistuvat palveluiden tuottamisessa. Työssä esitetään myös alustava vaatimuslista ehdotetulle mallille, esimerkiksi yhteysoperaattorien laatuvaatimukset. Väitöskirja esittelee myös liikkuvien Internet-teknologioiden viimeisimmän kehityksen. Työssä näytetään lisäksi standardointituloksia Internet-kykyisissä langattomissa arkkitehtuureissa

IEEE 802.21 in heterogeneous handover environments

Mestrado em Engenharia de Computadores e TelemáticaO desenvolvimento das capacidades tecnológicas dos terminais móveis, e das infra-estruturas que os suportam, potenciam novos cenários onde estes dispositivos munidos com interfaces de diferentes tecnologias vagueiam entre diferentes ambientes de conectividade. É assim necessário providenciar meios que facilitem a gestão de mobilidade, permitindo ao terminal ligar-se da melhor forma (i.e., optando pela melhor tecnologia) em qualquer altura. A norma IEEE 802.21 está a ser desenvolvida pelo Institute of Electrical and Electronics Engineers (IEEE) com o intuito de providenciar mecanismos e serviços que facilitem e optimizem handovers de forma independente da tecnologia. A norma 802.21 especifica assim um conjunto de mecanismos que potenciarão cenários como o descrito acima, tendo em conta a motivação e requerimentos apresentados por arquitecturas de redes futuras, como as redes de quarta geração (4G). Esta dissertação apresenta uma análise extensiva da norma IEEE 802.21, introduzindo um conjunto de simulações desenvolvidas para estudar o impacto da utilização de mecanismos 802.21 em handovers controlados por rede, numa rede de acesso mista composta por tecnologias 802.11 e 3G. Os resultados obtidos permitiram verificar a aplicabilidade destes conceitos a ambientes de próxima geração, motivando também uma descrição do desenho de integração de mecanismos 802.21 a arquitecturas de redes de quarta geração. ABSTRACT: The development of the technological capabilities of mobile terminals, and the infra-structures that support them, enable new scenarios where these devices using different technology interfaces roam in different connectivity environments. This creates a need for providing the means that facilitate mobility management, allowing the terminal to connect in the best way possible (i.e., by choosing the best technology) at any time. The IEEE 802.21 standard is being developed by the Institute of Electrical and Electronics Engineers (IEEE) to provide mechanisms and services supporting Media Independent Handovers. The 802.21 standard specifies a set of mechanisms that enable scenarios like the one described above, considering the motivation and requirements presented by future network architectures, such as the ones from fourth generation networks (4G). This thesis presents an extensive analysis of the IEEE 802.21 standard, introducing a set of simulations developed for studying the impact of using 802.21 mechanisms in network controlled handovers, in a mixed access network composed of 802.11 and 3G technologies. The obtained results allow the verification of the applicability of these concepts into next generation environments, also motivating the description of the design for integration of 802.21 mechanisms to fourth generation networks

Secure Service Provisioning (SSP) Framework for IP Multimedia Subsystem (IMS)

Mit dem Erscheinen mobiler Multimediadienste, wie z. B. Unified Messaging, Click-to-Dial-Applikationen, netzwerkübergeifende Multimedia-Konferenzen und nahtlose Multimedia-Streming-Dienste, begann die Konvergenz von mobilen Kommunikationsetzen und Festnetzen, begleitet von der Integration von Sprach- und Datenkommunikations-Übertragungstechnik Diese Entwicklungen bilden die Voraussetzung für die Verschmelzung des modernen Internet auf der einen Seite mit der Telekommunikation im klassischen Sinne auf der anderen. Das IP Multimedia-Subsystem (IMS) darf hierbei als die entscheidende Next-Generation-Service-Delivery-Plattform in einer vereinheitlichten Kommunikationswelt angesehen werden. Seine Architektur basiert auf einem modularen Design mit offenen Schnittstellen und bietet dedizierte Voraussetzungen zur Unterstützung von Multimedia-Diensten auf der Grundlage der Internet-Protokolle. Einhergehend mit dieser aufkommenden offenen Technologie stellen sich neue Sicherheits-Herausforderungen in einer vielschichtigen Kommunikationsinfrastruktur, im Wesentlichen bestehend aus dem Internet Protokoll (IP), dem SIP-Protokoll (Session Initiation Protocol) und dem Real-time Transport Protokoll (RTP). Die Zielsetzung des Secure Service Provisioning-Systems (SSP) ist, mögliche Angriffsszenarien und Sicherheitslücken in Verbindung mit dem IP Multimedia Subsystem zu erforschen und Sicherheitslösungen, wie sie von IETF, 3GPP und TISPAN vorgeschlagen werden, zu evaluieren. Im Rahmen dieser Forschungsarbeit werden die Lösungen als Teil des SSP-Systems berücksichtigt, mit dem Ziel, dem IMS und der Next-Generation-SDP einen hinreichenden Schutz zu garantieren. Dieser Teil, der als Sicherheitsschutzstufe 1 bezeichnet wird, beinhaltet unter anderem Maßnahmen zur Nutzer- und Netzwerk-Authentifizierung, die Autorisierung der Nutzung von Multimediadiensten und Vorkehrungen zur Gewährleistung der Geheimhaltung und Integrität von Daten im Zusammenhang mit dem Schutz vor Lauschangriffen, Session-Hijacking- und Man-in-the-Middle-Angriffen. Im nächsten Schritt werden die Beschränkungen untersucht, die für die Sicherheitsschutzstufe 1 charakteristisch sind und Maßnahmen zu Verbesserung des Sicherheitsschutzes entwickelt. Die entsprechenden Erweiterungen der Sicherheitsschutzstufe 1 führen zu einem Intrusion Detection and Prevention-System (IDP), das Schutz vor Denial-of-Service- (DoS) / Distributed-Denial-of-Service (DDoS)-Angriffen, missbräuchlicher Nutzung und Täuschungsversuchen in IMS-basierten Netzwerken bietet. Weder 3GPP noch TISPAN haben bisher Lösungen für diesen Bereich spezifiziert. In diesem Zusammenhang können die beschriebenen Forschungs- und Entwicklungsarbeiten einen Beitrag zur Standardisierung von Lösungen zum Schutz vor DoS- und DDoS-Angriffen in IMS-Netzwerken leisten. Der hier beschriebene Ansatz basiert auf der Entwicklung eines (stateful / stateless) Systems zur Erkennung und Verhinderung von Einbruchsversuchen (Intrusion Detection and Prevention System). Aus Entwicklungssicht wurde das IDP in zwei Module aufgeteilt: Das erste Modul beinhaltet die Basisfunktionen des IDP, die sich auf Flooding-Angriffe auf das IMS und ihre Kompensation richten. Ihr Ziel ist es, das IMS-Core-Netzwerk und die IMS-Ressourcen vor DoS- und DDoS-Angriffen zu schützen. Das entsprechende Modul basiert auf einer Online Stateless-Detection-Methodologie und wird aktiv, sobald die CPU-Auslastung der P-CSCF (Proxy-Call State Control Function) einen vordefinierten Grenzwert erreicht oder überschreitet. Das zweite Modul (IDP-AS) hat die Aufgabe, Angriffe, die sich gegen IMS Application Server (AS) richten abzufangen. Hierbei konzentrieren sich die Maßnahmen auf den Schutz des ISC-Interfaces zwischen IMS Core und Application Servern. Das betreffende Modul realisiert eine Stateful Detection Methodologie zur Erkennung missbräuchlicher Nutzungsaktivitäten. Während der Nutzer mit dem Application Server kommuniziert, werden dabei nutzerspezifische Zustandsdaten aufgezeichnet, die zur Prüfung der Legitimität herangezogen werden. Das IDP-AS prüft alle eingehenden Requests und alle abgehenden Responses, die von IMS Application Servern stammen oder die an IMS Application Server gerichtet sind, auf ihre Zulässigkeit im Hinblick auf die definierten Attack Rules. Mit Hilfe der Kriterien Fehlerfreiheit und Processing Delay bei der Identifikation potenzieller Angriffe wird die Leistungsfähigkeit der IDP-Module bewertet. Für die entsprechenden Referenzwerte werden hierbei die Zustände Nomallast und Überlast verglichen. Falls die Leistungsfähigkeit des IDP nicht unter den Erwartungen zurückbleibt, wird ein IDP-Prototyp zur Evaluation im Open IMS Playground des Fokus Fraunhofer 3Gb-Testbeds eingesetzt, um unter realen Einsatzbedingungen z. B. in VoIP-, Videokonferenz- , IPTV-, Presence- und Push-to-Talk-Szenarien getestet werden zu können.With the emergence of mobile multimedia services, such as unified messaging, click to dial, cross network multiparty conferencing and seamless multimedia streaming services, the fixed–mobile convergence and voice–data integration has started, leading to an overall Internet–Telecommunications merger. The IP Multimedia Subsystem (IMS) is considered as the next generation service delivery platform in the converged communication world. It consists of modular design with open interfaces and enables the flexibility for providing multimedia services over IP technology. In parallel this open based emerging technology has security challenges from multiple communication platforms and protocols like IP, Session Initiation Protocol (SIP) and Real-time Transport Protocol (RTP). The objective of Secure Service Provisioning (SSP) Framework is to cram the potential attacks and security threats to IP Multimedia Subsystem (IMS) and to explore security solutions developed by IETF, 3GPP and TISPAN. This research work incorporates these solutions into SSP Framework to secure IMS and next generation Service Delivery Platform (SDP). We define this part as level 1 security protection which includes user and network authentication, authorization to access multimedia services, providing confidentiality and integrity protection etc. against eavesdropping, session hijacking and man-in-the middle attacks etc. In the next step, we have investigated the limitations and improvements to level 1 security and proposed the enhancement and extension as level 2 security by developing Intrusion Detection and Prevention (IDP) system against Denial-of-Service (DoS)/Distributed DoS (DDoS) flooding attacks, misuses and frauds in IMS-based networks. These security threats recently have been identified by 3GPP and TISPAN but no solution is recommended and developed. Therefore our solution may be considered as recommendation in future. Our approach based on developing both stateless and stateful intrusion detection and prevention system. From development point of view, we have divided the work into two modules: the first module is IDP-Core; addressing and mitigating the flooding attacks in IMS core. Its objective is to protect the IMS resources and IMS-core entities from DoS/DDoS flooding attacks. This module based on online stateless detection methodology and activates when CPU processing load of P-CSCF (Proxy-Call State Control Function) reaches or crosses the defined threshold limit. The second module is IDP-AS; addressing and mitigating the misuse attacks facing to IMS Application Servers (AS). Its focus is to secure the ISC interface between IMS Core and Application Servers. This module is based on stateful misuse detection methodology by creating and comparing user state (partner) when he/she is communicating with application server to check whether user is performing legitimate or illegitimate action with attacks rules. The IDP-AS also compared the incoming request and outgoing response to and from IMS Application Servers with the defined attacks rules. In the performance analysis, the processing delay and attacks detection accuracy of both Intrusion Detection and Prevention (IDP) modules have been measured at Fraunhofer FOKUS IMS Testbed which is developed for research purpose. The performance evaluation based on normal and overload conditions scenarios. The results showed that the processing delay introduced by both IDP modules satisfied the standard requirements and did not cause retransmission of SIP REGISTER and INVITE requests. The developed prototype is under testing phase at Fraunhofer FOKUS 3Gb Testbed for evaluation in real world communication scenarios like VoIP, video conferencing, IPTV, presence, push-to-talk etc

Test and measurement environments for VANETs and MANETs

Mestrado em Engenharia de Computadores e TelemáticaA crescente necessidade por parte dos utilizadores em obterem acesso à Internet “em qualquer lugar e qualquer momento” tem incentivado investiga ção e desenvolvimento de abordagens capazes de resolver esta questão. Um dos maiores obstáculos em fornecer uma solução de acesso ubíquo à Internet tem sido a gestão de mobilidade. Nesta Tese de Mestrado ir-se-á implementar uma das soluções correntemente em desenvolvimento, integrando-a num ambiente MANET. A plataforma resultante pode ser posteriormente avaliada e até retiradas medidas de desempenho, podendo-se ainda tirar conclusões importantes sobre como um ambiente MANET se comporta numa plataforma de mobilidade global e acesso ubíquo. Na àrea de Sistemas de Transporte Inteligentes, tópicos como eficiência de tráfego e segurança dos utilizadores têm-se mostrado muito populares e deram in´ıcio a pesquisa extensiva em Redes Veículares Ad-Hoc (VANETs). Métodos tradicionais para investigação e desenvolvimento como testes com protótipos ou simulação computacional têm sido largamente usados. No entanto, os testes com protótipos são usualmente muito caros e a simulação computacional tem falta de precisão em ambientes sem fios. Esta Tese de Mestrado tem também por objectivo construir uma solução híbrida que combine os métodos de emulação e simulação. A solução proposta será implementada num testbed para VANETs. O testbed resultante irá permitir que multiplas instâncias de programas de routing reais possam ser executadas sobre um ambiente simulado computacionalmente. Assim poderão ser também retiradas elacções sobre o seu desempenho em características como o consumo de recursos e escalabilidade. ABSTRACT: The growing need from users to have internet access “whenever and wherever” has driven research to devise several approaches to cope with this issue. One of the greatest challenges in providing ubiquitous internet access has been the management of mobility. In this Master Thesis a solution currently under development, will be implemented integrating a MANET environment. The resulting testbed can later be evaluated and it’s performance measured, drawing important conclusions about how a MANET environment behaves in a global mobility and ubiquitous access framework. In the area of Intelligent Transportation System traffic efficiency and safety for users have become very popular topics and have triggered extensive research in Vehicular Ad-Hoc Networks (VANETs). Traditional methods for reaserch and development like field testing and simulation have been used. But field testing is usually very expensive expensive and simulation lacks accuracy in wireless environments. This Master Thesis also aims to provide a hybrid solution that combines the simulation and emulation methods. The proposed solution is implemented in a testbed for VANETs. The resulting testbed would allow multiple real routing instances to run simultaneously on a simulated environment. And to provide performance measures such as resource consumption and scalability

Optimização de recursos para difusão em redes de próxima geração

Doutoramento em ElectrotecniaEsta tese aborda o problema de optimização de recursos de rede, na entrega de Serviços de Comunicação em Grupo, em Redes de Próxima Geração que suportem tecnologias de difusão. De acordo com esta problemática, são feitas propostas que levam em atenção a evolução espectável das redes 3G em Redes Heterogéneas de Próxima Geração que incluam tecnologias de difusão tais como o DVB. A optimização de recursos em Comunicações em Grupo é apresentada como um desafio vertical que deve cruzar diversas camadas. As optimizações aqui propostas cobrem tanto a interface entre Aplicação e a Plataforma de Serviços para a disponibilização de serviços de comunicação em grupo, como as abstracções e mapeamentos feitos na interface entre a Rede Central e a Rede de Acesso Rádio. As optimizações propostas nesta tese, assumem que o caminho evolutivo na direcção de uma Rede de Próxima Geração é feito através do IP. Em primeiro lugar são endereçadas as optimizações entre a Aplicação e a Plataforma de Serviços que já podem ser integradas nas redes 3G existentes. Estas optimizações podem potenciar o desenvolvimento de novas e inovadoras aplicações, que através do uso de mecanismos de distribuição em difusão podem fazer um uso mais eficiente dos recursos de rede. De seguida são apresentadas optimizações ao nível da interface entre a Rede Central e a Rede de Acesso Rádio que abordam a heterogeneidade das redes futuras assim como a necessidade de suportar tecnologias de difusão. É ainda considerada a possibilidade de aumentar a qualidade de serviço de serviços de difusão através do mapeamento do IP multicast em portadoras unidireccionais. Por forma a validar todas estas optimizações, vários protótipos foram desenvolvidos com base num router avançado para redes de acesso de próxima geração. As funcionalidades e arquitectura de software desse router são também aqui apresentadas.This thesis addresses the problem of optimizing network resource usage, for the delivery of Group Services, in Next Generation Networks featuring broadcast technologies. In this scope, proposals are made according to the expected evolution of 3G networks into Next Generation Heterogeneous Networks that include broadcast technologies such as DVB. Group Communication resource optimization is considered a vertical challenge that must cross several layers. The optimizations here proposed cover both Application to Service Platform interfaces for group communication services, and Core Network to Radio Access Network interface abstractions and mappings. The proposed optimizations are also presented taking into consideration network evolution path towards an All-IP based Next Generation Network. First it is addressed the Application to Service Platform optimization, which can already be deployed over 3G networks. This optimization could potentiate the development of new and innovative applications that through the use of broadcast/multicast service delivery mechanisms could be more efficient network wise. Next proposals are made on the Core Network to Radio Access Network interfaces that address the heterogeneity of future networks and consider the need to support broadcast networks. It is also considered the possibility to increase the Quality of Service of broadcast/multicast services based on the dynamic mapping of IP multicast into unicast radio bearers. In order to validate these optimizations, several prototypes were built based on an advanced access router for next generation networks. Such access router functionalities and software architecture are also presented here