Convergence: the next big step

Recently, web based multimedia services have gained popularity and have proven themselves to be viable means of communication. This has inspired the telecommunication service providers and network operators to reinvent themselves to try and provide value added IP centric services. There was need for a system which would allow new services to be introduced rapidly with reduced capital expense (CAPEX) and operational expense (OPEX) through increased efficiency in network utilization. Various organizations and standardization agencies have been working together to establish such a system. Internet Protocol Multimedia Subsystem (IMS) is a result of these efforts. IMS is an application level system. It is being developed by 3GPP (3rd Generation Partnership Project) and 3GPP2 (3rd Generation Partnership Project 2) in collaboration with IETF (Internet Engineering Task Force), ITU-T (International Telecommunication Union – Telecommunication Standardization Sector), and ETSI (European Telecommunications Standards Institute) etc. Initially, the main aim of IMS was to bring together the internet and the cellular world, but it has extended to include traditional wire line telecommunication systems as well. It utilizes existing internet protocols such as SIP (Session Initiation Protocol), AAA (Authentication, Authorization and Accounting protocol), and COPS (Common Open Policy Service) etc, and modifies them to meet the stringent requirements of reliable, real time communication systems. The advantages of IMS include easy service quality management (QoS), mobility management, service control and integration. At present a lot of attention is being paid to providing bundled up services in the home environment. Service providers have been successful in providing traditional telephony, high speed internet and cable services in a single package. But there is very little integration among these services. IMS can provide a way to integrate them as well as extend the possibility of various other services to be added to allow increased automation in the home environment. This thesis extends the concept of IMS to provide convergence and facilitate internetworking of the various bundled services available in the home environment; this may include but is not limited to communications (wired and wireless), entertainment, security etc. In this thesis, I present a converged home environment which has a number of elements providing a variety of communication and entertainment services. The proposed network would allow effective interworking of these elements, based on IMS architecture. My aim is to depict the possible advantages of using IMS to provide convergence, automation and integration at the residential level

Identification of Technologies for Provision of Future Aeronautical Communications

This report describes the process, findings, and recommendations of the second of three phases of the Future Communications Study (FCS) technology investigation conducted by NASA Glenn Research Center and ITT Advanced Engineering & Sciences Division for the Federal Aviation Administration (FAA). The FCS is a collaborative research effort between the FAA and Eurocontrol to address frequency congestion and spectrum depletion for safety critical airground communications. The goal of the technology investigation is to identify technologies that can support the longterm aeronautical mobile communication operating concept. A derived set of evaluation criteria traceable to the operating concept document is presented. An adaptation of the analytical hierarchy process is described and recommended for selecting candidates for detailed evaluation. Evaluations of a subset of technologies brought forward from the prescreening process are provided. Five of those are identified as candidates with the highest potential for continental airspace solutions in L-band (P-34, W-CDMA, LDL, B-VHF, and E-TDMA). Additional technologies are identified as best performers in the unique environments of remote/oceanic airspace in the satellite bands (Inmarsat SBB and a custom satellite solution) and the airport flight domain in C-band (802.16e). Details of the evaluation criteria, channel models, and the technology evaluations are provided in appendixes

A Denial-of-Service Attack to GSM/UMTS Networks via Attach Procedure

In this thesis I describe an attack to the security of a Public Land Mobile Network allowing an unauthenticated malicious mobile device to inject traffic in the mobile operator's infrastructure. I show that using a few hundreds of malicious devices and without any SIM module it is possible to inject in the mobile infrastructure high levels of signalling traffic targeted at the Home Location Register, thus causing significant service degradation up to a full-fledged Denial-of-Service attack

Self-diagnosing and optimization of low coverage and high interference in 3G/4G: radio access networks

Mestrado em Engenharia Electrónica e Telecomunicações - DissertaçãoSelf-Organizing Networks (SON) solutions have been developed and implemented in the last years as a Mobile Network Operator (MNO) strategy to deal with the complexity of current networks. This research work, focuses on the self-optimization branch of SON solutions. It aims to empower a network with automatic capabilities for detecting and optimizing poor Radio Frequency (RF) performance scenarios. The detection and optimization of those scenarios, is based on Drive Test (DT) data. This leads to the development of a DT classi cation model to assert the quality of data collected through DT for a given cell, as it supports all decision making in terms of detection and optimization of poor RF situations. The DT model was calibrated with subjective testing in the form of inquiries made to fty Radio Access Network (RAN) engineers. Three algorithms were implemented for detection of low coverage and high interference scenarios. Besides identifying and dividing into clusters the DT data that denotes each problem, harshness metrics at cell and cluster level allow to identify the most severe situations. Moreover, an antenna physical parameter optimization algorithm, based on a Particle Swarm Optimization (PSO) algorithm, is able to purpose new Electrical Downtilt (EDT), Mechanical Downtilt (MDT) or the antenna orientation to improve or x the detected RF problems. All algorithms were tested with real MNO DT data and network topology, mainly on urban scenarios, where the detection and optimization is more critical for MNO. Regarding the detection algorithms, in urban scenario, it was established that the situations of high interference were more prevailing than the low coverage. The antenna self-optimization algorithm achieved an average gain of 78% on the tested cases.As redes SON têm sido, cada vez mais, uma das fortes apostas por parte das operadoras móveis para fazer face a crescente complexidade das redes móveis. Este trabalho de pesquisa foca-se no ramo, das redes SON, de optimização automática. O objectivo e dotar uma rede móvel de capacidades de detecção e optimização de situações de má performance rádio. Tendo em conta que toda a detecção e optimização e baseada em dados recolhidos por DT, surgiu a necessidade de desenvolver um modelo de qualidade para DT. Este modelo e usado como referência em termos de qualidade de dados disponíveis, para cada célula analisada. O modelo de qualidade de DT foi calibrado através de questionários subjectivos, realizados a cinquenta engenheiros rádio. Foram implementados três algoritmos para detecção de situações de má cobertura e interferência. Além de identificar e dividir em clusters os dados de DT com cada um dos problemas mencionados, as métricas de gravidade ao nível do cluster e da célula, permitem identificar os cenários mais graves. Em termos de optimizaçãoo, foi desenvolvido e implementado um algoritmo de optimização de tilts eléctrico e mecânico ou a orientação da antena, com base num algoritmo PSO. Todos os algoritmos foram testados com dados reais de DT e de topologia de rede, principalmente em cenários urbanos. No que diz respeito aos algoritmos de detecção, em cenário urbano, foi concluído que as situações de excesso de interferência são mais abundantes do que as situações de má cobertura. O algoritmo de optimização dos parâmetros físicos de antenas, para os casos testados, obteve um ganho médio de 78%.N/

Study of continuous-phase four-state modulation for cordless telecommunications. Assessment by simulation of CP-QFSK as an alternative modulation scheme for TDMA digital cordless telecommunications systems operating in indoor applications

One of the major driving elements behind the explosive boom in wireless revolution is the advances in the field of modulation which plays a fundamental role in any communication system, and especially in cellular radio systems. Hence, the elaborate choice of an efficient modulation scheme is of paramount importance in the design and employment of any communications system. Work presented in this thesis is an investigation (study) of the feasibility of whether multilevel FSK modulation scheme would provide a viable alternative modem that can be employed in TDMA cordless communications systems. In the thesis the design and performance analysis of a non-coherent multi-level modem that offers a great deal of bandwidth efficiency and hardware simplicity is studied in detail. Simulation results demonstrate that 2RC pre-modulation filter pulse shaping with a modulation index of 0.3, and pre-detection filter normalized equivalent noise bandwidth of 1.5 are optimum system parameter values. Results reported in chapter 5 signify that an adjacent channel rejection factor of around 40 dB has been achieved at channel spacing of 1.5 times the symbol rate while the DECT system standards stipulated a much lower rejection limit criterion (25-30dB), implying that CP-QFSK modulation out-performs the conventional GMSK as it causes significantly less ACI, thus it is more spectrally efficient in a multi-channel system. However, measured system performance in terms of BER indicates that this system does not coexist well with other interferers as at delay spreads between 100ns to 200ns, which are commonly encountered in such indoor environment, a severe degradation in system performance apparently caused by multi-path fading has been noticed, and there exists a noise floor of about 40 dB, i.e. high irreducible error rate of less than 5.10-3. Implementing MRC diversity combiner and BCH codec has brought in a good gain.Higher Education Ministr

Multimedia in mobile networks: Streaming techniques, optimization and User Experience

1.UMTS overview and User Experience 2.Streaming Service & Streaming Platform 3.Quality of Service 4.Mpeg-4 5.Test Methodology & testing architecture 6.Conclusion

Fronthaul C-RAN baseado em ethernet

For the last decade mobile data traffic has been increasing at impressive rates. The proliferation of mobile devices together with high-bandwidth services like video and music streaming, social media and other cloud services have increased the load on top of the mobile network infrastructure. In order to support this massive increase in both users and bandwidth the next generation of mobile telecommunications network - 5G - explores new approaches, like the utilization of new frequency bands and the densification of base stations. This kind of requirements along with the inefficiency of the co-location of base band processing near the radio units encourages a rethink of traditional radio access networks. In this scenario emerges the C-RAN paradigm that intend to centralize all the base band processing (BBU) and replace current base stations for simpler, more efficient and compact solutions that only incorporate the radio front-end and respective radio processing (RRH). In addition to these benefits, centralized processing facilitates virtualization and resource sharing, interference management and cooperative processing technologies. This split of functions brings however, some challenges in respect to the data rates, bandwidth and latency in the link that connects BBUs and RRHs - the fronthaul. Today’s existing standards like CPRI weren’t originally designed for such applications and present some intrinsic bandwidth and flexibility limitations. It’s considered that another approach, based on packet switching, could mitigate some of these problems in addition to bring some advantages such as statistical multiplexing, flexible routing and compatibility with current widespread packet switching networks. They do however, present a number of challenges regarding latency and synchronization. This dissertation work focuses on the study and development of a fronthaul solution based in 10 Gigabit Ethernet over optical fiber. Development is done on top of two development kits based in Field Programmable Gate Array (FPGA) and implemented in an already operational C-RAN test-bed - currently with CPRI based fronthaul - at the Instituto de Telecomunicações - Aveiro.Durante a última década o tráfego de dados móveis tem aumentado a um ritmo impressionante. A proliferação de dispositivos móveis juntamente com serviços consumidores de grande largura de banda como streaming de vídeo e música, redes sociais e serviços na cloud têm colocado grande pressão na infraestrutura da rede móvel. Para suportar este aumento massivo de utilizadores e largura de banda a próxima geração de telecomunicações móveis – o 5G – explora novos conceitos, entre eles a utilização de bandas de frequências mais elevadas e a massificação das estações base. A este tipo de requisitos junta-se o facto da ineficiência da co-localização do processamento junto da unidade de rádio que incentiva a uma restruturação da arquitectura tradicional das redes móveis. Neste cenário surge o paradigma C-RAN, que pretende centralizar todo o processamento em banda base (BBU) e substituir as base stations atuais por soluções mais simples, eficientes e compactas que englobam apenas o processamento da parte de rádio e respetivo front-end de rádio frequência (RRH). Para além destes beneficios, a centralização do processamento facilita a virtualização e partilha de recursos, a gestão da interferência e tecnologias de processamento cooperativo. Esta divisão de funções traz no entanto alguns desafios no que diz respeito a largura de banda, taxas de dados e latências na interligação entre BBUs e RRHs – o fronthaul. Standards atualmente utilizados no link de fronthaul como o CPRI não foram originalmente desenhados para aplicações desta dimensão e apresentam algumas limitações, sendo intrinsecamente pouco flexíveis e eficientes. Acredita-se que outro tipo de abordagem, baseada em comutação de pacotes, poderia mitigar alguns destes problemas para além de trazer vantagens como a multiplexagem estatística, routing flexível e compatibilidade com redes de comutação de pacotes actuais. Apresentam no entanto vários desafios a nível de latência e sincronização associados. Este trabalho de dissertação foca-se então no estudo e desenvolvimento de uma solução para o fronthaul baseada em 10 Gigabit Ethernet sobre fibra ótica. O desenvolvimento será feito em dois kits de desenvolvimento baseados em Field Programmable Gate Array (FPGA) e implementado num demonstrador C-RAN já operacional - com fronthaul atualmente baseado em CPRI - no Instituto de Telecomunicações de Aveiro.Mestrado em Engenharia Eletrónica e Telecomunicaçõe