This research addresses the concept of radio resource allocation for cellular communications systems operating in congested and contested environments with an emphasis on end-to-end quality of service (QoS). The radio resource allocation is cast under a proportional fairness formulation which translates to a convex optimization problem. Moreover, the resource allocation scheme considers subscription-based and traffic differentiation in order to meet the QoS requirements of the applications running on the user equipment in the system. The devised resource allocation scheme is realized through a centralized and a distributed architecture and solution algorithms for the aforementioned architectures is derived and implemented in the mobile devices and the base stations. The sensitivity of the resource allocation scheme to the temporal dynamics of the quantity of the users in the system is investigated. Furthermore, the sensitivity of the resource allocation scheme to the temporal dynamics in the application usage percentages is accounted for. In addition, a transmission overhead of the centralized and distributed architectures for the resource allocation schemes is performed. Furthermore, the resource allocation scheme is modified to account for a possible additive bandwidth done through spectrum sharing in congested and contested environments, in particular spectrally coexistent radar systems. The radar-spectrum additive portion is devised in a way to ensure fairness of the allocation, high bandwidth utilization, and interference avoidance. In order to justify the aforesaid modification, the interference from radar systems into the Long Term Evolution (LTE) as the predominant 4G technology is studies to confirm the possibility of the spectrum sharing. The preceding interference analysis contains a detailed simulation of radar systems, propagation path loss models, and a third generation partnership project compliant LTE system. The propagation models are Free Space Path Loss (FSPL) and Irregular Terrain Model (ITM). The LTE systems under consideration are macro cell, outdoor small cells, and indoor small cells. Furthermore, the resource allocation under channel consideration is formalized such that the resources are allocated under a congested environment and based on the quality of channel the users have in the network as well as the quality of service requirements of the applications running on the mobile devices. / Ph. D.

The Quality of Service (QoS) routing approach is gaining an increasing interest in the Internet community due to the new emerging Internet applications such as real-time multimedia applications. These applications require better levels of quality of services than those supported by best effort networks. Therefore providing such services is crucial to many real time and multimedia applications which have strict quality of service requirements regarding bandwidth and timeliness of delivery. QoS routing is a major component in any QoS architecture and thus has been studied extensively in the literature. Scalability is considered one of the major issues in designing efficient QoS routing algorithms due to the high cost of QoS routing both in terms of computational effort and communication overhead. Localized quality of service routing is a promising approach to overcome the scalability problem of the conventional quality of service routing approach. The localized quality of service approach eliminates the communication overhead because it does not need the global network state information. The main aim of this thesis is to contribute towards the localised routing area by proposing and developing some new models and algorithms. Toward this goal we make the following major contributions. First, a scalable and efficient QoS routing algorithm based on a localised approach to QoS routing has been developed and evaluated. Second, we have developed a path selection technique that can be used with existing localized QoS routing algorithms to enhance their scalability and performance. Third, a scalable and efficient hierarchical QoS routing algorithm based on a localised approach to QoS routing has been developed and evaluated.

Active Queue Management (AQM) schemes are used for ensuring the Quality of Service (QoS) in telecommunication networks. However, they are sensitive to parameter settings and have weaknesses in detecting and controlling congestion under dynamically changing network situations. Another drawback for the AQM algorithms is that they have been applied only on the Markovian models which are considered as Short Range Dependent (SRD) traffic models. However, traffic measurements from communication networks have shown that network traffic can exhibit self-similar as well as Long Range Dependent (LRD) properties. Therefore, it is important to design new algorithms not only to control congestion but also to have the ability to predict the onset of congestion within a network. An aim of this research is to devise some new congestion control methods for communication networks that make use of various traffic characteristics, such as LRD, which has not previously been employed in congestion control methods currently used in the Internet. A queueing model with a number of ON/OFF sources has been used and this incorporates a novel congestion prediction algorithm for AQM. The simulation results have shown that applying the algorithm can provide better performance than an equivalent system without the prediction. Modifying the algorithm by the inclusion of a sliding window mechanism has been shown to further improve the performance in terms of controlling the total number of packets within the system and improving the throughput. Also considered is the important problem of maintaining QoS constraints, such as mean delay, which is crucially important in providing satisfactory transmission of real-time services over multi-service networks like the Internet and which were not originally designed for this purpose. An algorithm has been developed to provide a control strategy that operates on a buffer which incorporates a moveable threshold. The algorithm has been developed to control the mean delay by dynamically adjusting the threshold, which, in turn, controls the effective arrival rate by randomly dropping packets. This work has been carried out using a mixture of computer simulation and analytical modelling. The performance of the new methods that have.

<p>Development of software for embedded real-time systems poses severalchallenges. Hard and soft constraints on timing, and usually considerableresource limitations, put important constraints on the development. Thetraditional way of coping with these issues is to produce a fully static design,i.e. one that is fully fixed already during design time.Current trends in the area of embedded systems, including the emergingopenness in these types of systems, are providing new challenges for theirdesigners – e.g. integration of new software during runtime, software upgradeor run-time adaptation of application behavior to facilitate better performancecombined with more ecient resource usage. One way to reach these goals is tobuild self-configurable systems, i.e. systems that can resolve such issues withouthuman intervention. Such mechanisms may be used to promote increasedsystem openness.This thesis covers some of the challenges involved in that development.An overview of the current situation is given, with a extensive review ofdi erent concepts that are applicable to the problem, including adaptivitymechanisms (incluing QoS and load balancing), middleware and relevantdesign approaches (component-based, model-based and architectural design).A middleware is a software layer that can be used in distributed systems,with the purpose of abstracting away distribution, and possibly other aspects,for the application developers. The DySCAS project had as a major goaldevelopment of middleware for self-configurable systems in the automotivesector. Such development is complicated by the special requirements thatapply to these platforms.Work on the implementation of an adaptive middleware, DyLite, providingself-configurability to small-scale microcontrollers, is described andcovered in detail. DyLite is a partial implementation of the concepts developedin DySCAS.Another area given significant focus is formal modeling of QoS andresource management. Currently, applications in these types of systems arenot given a fully formal definition, at least not one also covering real-timeaspects. Using formal modeling would extend the possibilities for verificationof not only system functionality, but also of resource usage, timing and otherextra-functional requirements. This thesis includes a proposal of a formalismto be used for these purposes.Several challenges in providing methodology and tools that are usablein a production development still remain. Several key issues in this areaare described, e.g. version/configuration management, access control, andintegration between di erent tools, together with proposals for future workin the other areas covered by the thesis.</p> / <p>Utveckling av mjukvara för inbyggda realtidssystem innebär flera utmaningar.Hårda och mjuka tidskrav, och vanligtvis betydande resursbegränsningar,innebär viktiga inskränkningar på utvecklingen. Det traditionellasättet att hantera dessa utmaningar är att skapa en helt statisk design, d.v.s.en som är helt fix efter utvecklingsskedet.Dagens trender i området inbyggda system, inräknat trenden mot systemöppenhet,skapar nya utmaningar för systemens konstruktörer – exempelvisintegration av ny mjukvara under körskedet, uppgradering av mjukvaraeller anpassning av applikationsbeteende under körskedet för att nå bättreprestanda kombinerat med e ektivare resursutnyttjande. Ett sätt att nå dessamål är att bygga självkonfigurerande system, d.v.s. system som kan lösa sådanautmaningar utan mänsklig inblandning. Sådana mekanismer kan användas föratt öka systemens öppenhet.Denna avhandling täcker några av utmaningarna i denna utveckling. Enöversikt av den nuvarande situationen ges, med en omfattande genomgångav olika koncept som är relevanta för problemet, inklusive anpassningsmekanismer(inklusive QoS och lastbalansering), mellanprogramvara och relevantadesignansatser (komponentbaserad, modellbaserad och arkitekturell design).En mellanprogramvara är ett mjukvarulager som kan användas i distribueradesystem, med syfte att abstrahera bort fördelning av en applikation överett nätverk, och möjligtvis även andra aspekter, för applikationsutvecklarna.DySCAS-projektet hade utveckling av mellanprogramvara för självkonfigurerbarasystem i bilbranschen som ett huvudmål. Sådan utveckling försvåras avde särskilda krav som ställs på dessa plattformarArbete på implementeringen av en adaptiv mellanprogramvara, DyLite,som tillhandahåller självkonfigurerbarhet till småskaliga mikrokontroller,beskrivs och täcks i detalj. DyLite är en delvis implementering av konceptensom utvecklats i DySCAS.Ett annat område som får särskild fokus är formell modellering av QoSoch resurshantering. Idag beskrivs applikationer i dessa områden inte heltformellt, i varje fall inte i den mån att realtidsaspekter täcks in. Att användaformell modellering skulle utöka möjligheterna för verifiering av inte barasystemfunktionalitet, men även resursutnyttjande, tidsaspekter och andraicke-funktionella krav. Denna avhandling innehåller ett förslag på en formalismsom kan användas för dessa syften.Det återstår många utmaningar innan metodik och verktyg som är användbarai en produktionsmiljö kan erbjudas. Många nyckelproblem i områdetbeskrivs, t.ex. versions- och konfigurationshantering, åtkomststyrning ochintegration av olika verktyg, tillsammans med förslag på framtida arbete iövriga områden som täcks av avhandlingen.</p> / DySCAS

While there has always been a tremendous demand for streaming video over Wireless networks, the nature of the application still presents some challenging issues. These applications that transmit coded video sequence data over best-effort networks like the Internet, the application must cope with the changing network behaviour; especially, the source encoder rate should be controlled based on feedback from a channel estimator that explores the network intermittently. The arrival of powerful video compression techniques such as H.264, which advance in networking and telecommunications, opened up a whole new frontier for multimedia communications. The aim of this research is to transmit the H.264 coded video frames in the wireless network with maximum reliability and in a very efficient manner. When the H.264 encoded video sequences are to be transmitted through wireless network, it faces major difficulties in reaching the destination. The characteristics of H.264 video coded sequences are studied fully and their capability of transmitting in wireless networks are examined and a new approach called Optimal Packet Fragmentation (OPF) is framed and the H.264 coded sequences are tested in the wireless simulated environment. This research has three major studies involved in it. First part of the research has the study about Long Range Dependence (LRD) and the ways by which the self-similarity can be estimated. For estimating the LRD a few studies are carried out and Wavelet-based estimator is selected for the research because Wavelets incarcerate both time and frequency features in the data and regularly provides a more affluent picture than the classical Fourier analysis. The Wavelet used to estimate the self-similarity by using the variable called Hurst Parameter. Hurst Parameter tells the researcher about how a data can behave inside the transmitted network. This Hurst Parameter should be calculated for a more reliable transmission in the wireless network. The second part of the research deals with MPEG-4 and H.264 encoder. The study is carried out to prove which encoder is superior to the other. We need to know which encoder can provide excellent Quality of Service (QoS) and reliability. This study proves with the help of Hurst parameter that H.264 is superior to MPEG-4. The third part of the study is the vital part in this research; it deals with the H.264 video coded frames that are segmented into optimal packet size in the MAC Layer for an efficient and more reliable transfer in the wireless network. Finally the H.264 encoded video frames incorporated with the Optimal Packet Fragmentation are tested in the NS-2 wireless simulated network. The research proves the superiority of H.264 video encoder and OPF's master class.

Os atuais sistemas eletrônicos desenvolvidos na forma de SoCs (Sistemas-sobre-Silício) são caracterizados pelo incremento de informação crítica que é capturada, armazenada e processada. Com a introdução dos SoCs nos sistemas distribuídos que promovem o compartilhamento dos recursos, a segurança vem se transformando num requisito de projeto extremamente importante. Os atuais SoCs são alvo de ataques. O desafio consiste em projetar um SoC seguro que satisfaça os requisitos de segurança e desempenho, próprios para cada aplicação. A estrutura de comunicação está se tornando o coração do SoC. Esta possui um impacto significativo no desempenho do sistema. A inclusão de serviços de segurança na estrutura de comunicação é vantajosa devido à sua capacidade de: 1) monitorar a informação transmitida; 2) detectar violações; 3) bloquear ataques; e 4) fornecer informações para diagnóstico e ativação de mecanismos de recuperação e defesa. O presente trabalho propõe a implementação do conceito de QoSS (Qualidade do Serviço de Segurança) no projeto da estrutura de comunicação baseada em redes intrachip (NoCs, Network-on-Chip). QoSS permite a inclusão da segurança como uma dimensão de QoS (Quality-of-Sevice), admitindo a existência de diferentes níveis de proteção. A adoção do QoSS no projeto das NoCs permite a exploração do espaço de projeto das NoCs levando em consideração o compromisso entre a segurança do sistema e o desempenho do sistema. A inclusão do QoSS na NoC é realizada através de uma metodologia que inclui 5 etapas: definição, descrição, implementação, avaliação e otimização. Como resultado é obtido um conjunto de NoCsQoSS que satisfazem os requisitos de segurança e desempenho do sistema. Criamos neste trabalho o ambiente de simulação APOLLO que fornece suporte na rápida exploração do espaço de soluções a partir de modelos SystemC-TLM do SoC. Neste trabalho, apresentamos três estudos de caso que utilizam a nossa metodologia de projeto de NoCs com QoSS na implementação de políticas de segurança estática e dinâmica. Os serviços de segurança de controle de acesso e autenticação foram implementados de duas formas: na interface da rede e no roteador. Realizamos a avaliação da eficácia e eficiência das NoCs resultantes sob diferentes condições de ataques e de tráfego, resultado da variação topológica do tráfego, natureza e tipo de tráfego. Mostramos que a implementação da segurança no roteador é mais eficiente que a implementação na interface da rede em termos de latência e potência sob todas as diferentes condições de tráfego. Porém, a utilização na interface permite a inclusão das características da segurança na NoC de uma maneira mais simples. Desta forma para sistemas complexos a implementação na interface é vantajosa. / As embedded electronic systems are pervading our lives, security is emerging as an extremely important design requirement. Due to the increasing complexity, intrinsic embedded constraints and strict requirements, security and performance are considered challenging tasks. Most of the current electronic systems embedded in a SoC (System-on-Chip) are used to capture, store, manipulate and access sensitive data and perform several critical functions without security guarantee. The challenge is to provide SoC security that allows a trustworthy system that meets the security and performance requirements. As security requirements vary dramatically for different applications, differentiated security services are necessary. The SoC communication structure is becoming the heart of the SoC. It has a significant impact on the overall system performance. The security services integration at the communication structure take advantage of its wide system visibility and critical role in enabling the system operation. It is able to: 1) monitor data transfer; 2) detect attacks; 3) block attacks; and 4) supply information for trigger suitable recovery mechanisms. This work proposes the implementation of the QoSS (Quality-of-Security-Service) concept at the NoC-based communication structure design. QoSS is a novel concept for data protection that introduces security as a dimension of QoS. In contrast with previous works, the different security levels deployment allow a best trade-of the system security and performance requirements. The QoSS integration is carried out trough a 5 step methodology: definition, description, implementation, evaluation and optimization. As a result a set of NoCs-QoSS that satisfies the security and performance requirements are obtained. We use the framework APOLLO that integrates a set of tools, allowing the fast exploration of the huge NoC design space. In this work we present 2 study cases that uses our methodology in order to design a NoC-QoSS that supports static and a dynamic security policies and also satisfies the security and performance requirements. Two security services: Access Control and authentication are implemented at the NoC interface and at the NoC router. The final configurations are evaluated under different traffic and attack conditions. We show that the security implementation at the router is latency and power consumption efficient that the implementation at the network interface under all the traffic conditions. However, the security implementation at the network interface allows the integration of the security characteristics in a simpler way.

Os atuais sistemas eletrônicos desenvolvidos na forma de SoCs (Sistemas-sobre-Silício) são caracterizados pelo incremento de informação crítica que é capturada, armazenada e processada. Com a introdução dos SoCs nos sistemas distribuídos que promovem o compartilhamento dos recursos, a segurança vem se transformando num requisito de projeto extremamente importante. Os atuais SoCs são alvo de ataques. O desafio consiste em projetar um SoC seguro que satisfaça os requisitos de segurança e desempenho, próprios para cada aplicação. A estrutura de comunicação está se tornando o coração do SoC. Esta possui um impacto significativo no desempenho do sistema. A inclusão de serviços de segurança na estrutura de comunicação é vantajosa devido à sua capacidade de: 1) monitorar a informação transmitida; 2) detectar violações; 3) bloquear ataques; e 4) fornecer informações para diagnóstico e ativação de mecanismos de recuperação e defesa. O presente trabalho propõe a implementação do conceito de QoSS (Qualidade do Serviço de Segurança) no projeto da estrutura de comunicação baseada em redes intrachip (NoCs, Network-on-Chip). QoSS permite a inclusão da segurança como uma dimensão de QoS (Quality-of-Sevice), admitindo a existência de diferentes níveis de proteção. A adoção do QoSS no projeto das NoCs permite a exploração do espaço de projeto das NoCs levando em consideração o compromisso entre a segurança do sistema e o desempenho do sistema. A inclusão do QoSS na NoC é realizada através de uma metodologia que inclui 5 etapas: definição, descrição, implementação, avaliação e otimização. Como resultado é obtido um conjunto de NoCsQoSS que satisfazem os requisitos de segurança e desempenho do sistema. Criamos neste trabalho o ambiente de simulação APOLLO que fornece suporte na rápida exploração do espaço de soluções a partir de modelos SystemC-TLM do SoC. Neste trabalho, apresentamos três estudos de caso que utilizam a nossa metodologia de projeto de NoCs com QoSS na implementação de políticas de segurança estática e dinâmica. Os serviços de segurança de controle de acesso e autenticação foram implementados de duas formas: na interface da rede e no roteador. Realizamos a avaliação da eficácia e eficiência das NoCs resultantes sob diferentes condições de ataques e de tráfego, resultado da variação topológica do tráfego, natureza e tipo de tráfego. Mostramos que a implementação da segurança no roteador é mais eficiente que a implementação na interface da rede em termos de latência e potência sob todas as diferentes condições de tráfego. Porém, a utilização na interface permite a inclusão das características da segurança na NoC de uma maneira mais simples. Desta forma para sistemas complexos a implementação na interface é vantajosa. / As embedded electronic systems are pervading our lives, security is emerging as an extremely important design requirement. Due to the increasing complexity, intrinsic embedded constraints and strict requirements, security and performance are considered challenging tasks. Most of the current electronic systems embedded in a SoC (System-on-Chip) are used to capture, store, manipulate and access sensitive data and perform several critical functions without security guarantee. The challenge is to provide SoC security that allows a trustworthy system that meets the security and performance requirements. As security requirements vary dramatically for different applications, differentiated security services are necessary. The SoC communication structure is becoming the heart of the SoC. It has a significant impact on the overall system performance. The security services integration at the communication structure take advantage of its wide system visibility and critical role in enabling the system operation. It is able to: 1) monitor data transfer; 2) detect attacks; 3) block attacks; and 4) supply information for trigger suitable recovery mechanisms. This work proposes the implementation of the QoSS (Quality-of-Security-Service) concept at the NoC-based communication structure design. QoSS is a novel concept for data protection that introduces security as a dimension of QoS. In contrast with previous works, the different security levels deployment allow a best trade-of the system security and performance requirements. The QoSS integration is carried out trough a 5 step methodology: definition, description, implementation, evaluation and optimization. As a result a set of NoCs-QoSS that satisfies the security and performance requirements are obtained. We use the framework APOLLO that integrates a set of tools, allowing the fast exploration of the huge NoC design space. In this work we present 2 study cases that uses our methodology in order to design a NoC-QoSS that supports static and a dynamic security policies and also satisfies the security and performance requirements. Two security services: Access Control and authentication are implemented at the NoC interface and at the NoC router. The final configurations are evaluated under different traffic and attack conditions. We show that the security implementation at the router is latency and power consumption efficient that the implementation at the network interface under all the traffic conditions. However, the security implementation at the network interface allows the integration of the security characteristics in a simpler way.

In the next generation of networks we will begin to see the true convergence of voice, multimedia, and data traffic. This merging of various dedicated networks will occur both in the wired and wireless domains. Given the growth in the areas of wireless voice and data, we see that the combination of mobile and Internet communication constitutes the driving force behind the third-generation wireless system and makes the basis for the fourth-generation wireless system. For services like voice over IP over wireless (VoIPoW), the main challenge is to achieve QoS and spectrum efficiency. In order to support better QoS the IETF Mobile IP Working Group is discussing a number of enhancements to the base protocol to reduce the latency, packet loss and signaling overhead experienced during handoff. This support also includes both the call admission and the subsequent scheduling of packet transmissions. In this thesis, we will first survey the work done on issues related to QoS provisioning for wireless network and then will address bandwidth allocation problem in packet radio network with special emphasis on wireline to wireless internetworking zone. The main aim of the thesis is to evolve a strategy to reduce the call dropping probability by negotiating the QoS in those conditions when we do not have the sufficient resources (mainly bandwidth) to allocate. In order to achieve the QoS we have investigated the behaviour of the Real-time Voice traffic on a wireless link and its relation to the associated quality of service. This investigation opens a way for QoS negotiation, in a condition like during handoff, when the network is not able to sustain the negotiated bandwidth. The main results of this work are, that even with reduced bandwidth, quality for speech can be maintained at a reasonable level and this way the call dropping can be reduced. Such a scheme is useful in those conditions when we do not have the sufficient bandwidth to allocate like during a handoff of a mobile host from one cell to another. Moreover the bandwidth is a scarce resource in wireless domain so there should be an efficient call admission control policy. Many call admission control policies are proposed in the literature; here we propose a simple scheme for real-time traffic, specially speech, in a base station which increases the system throughput. In addition to above, we have also experimented with Cellular IP, one of the implementations of proposed micro-mobility architecture to provide faster handoff and seamless mobility in wired and wireless network.

The aim of this work is to understand the requirements behind Quality of Service (QoS) for Multihop Wireless Networks and evaluate the performance of different such strategies. This work starts by establishing the basis for requirement of QoS and evaluates different approaches for providing QoS. Bandwidth is selected as the most important resource amongst the resources identified for ensuring QoS. The problem is modeled as an optimization problem that tries to maximize the amount of bandwidth available in the system while providing bounds over the bandwidth available over a route. Other QoS parameters are bound by hard limits and are not involved in the optimization problem. The existence of spatial reuse rules has been established through simulations for a TCP based network. This establishes that the reuse rules are independent of the MAC and network layer protocols used. This idea is used in designing the simulations for strategies that use controlled spatial reuse and give known bounds for QoS. Simulations take the network and a set of connections to generate the best possible schedule that guarantees bandwidth to individual connections and maximizes the total number of slots used in the entire system. The total number of slots used is a measure of the bandwidth in use. The set of graphs and connections is generated by a random graph and connection generator and the data set is large enough to average the results. There are two different approaches used for scheduling the connections. The first approach uses graph coloring and provides a simpler implementation in terms of network deployments. Second approach uses on-demand slot allocation. The approaches are compared for their pros and cons. The first approach uses graph coloring to allocate fixed number of slots to each link. This makes an equivalent of a wired network with fixed bandwidth over each link. This network is simpler to operate and analyze at the cost of one time expense of graph coloring. The assumption here is that the network is static or has low mobility. The on demand approach is more flexible in terms of slot assignment and is adaptable to the changing traffic patterns. The cons are that connection establishment is more expensive in terms of bandwidth required and is more complicated and difficult to analyze. The advantages include low initial network establishment cost and accommodation of mobility.

在未來異質網路的整合環境中，QoS的問題益形重要，而以現今的網路環境而言，最有可能的異質網路整合是UMTS與WLAN。在本計畫中，我們將以UMTS與WLAN的異質網路整合環境作為基礎，提出Pricing-Improved QoS的觀念，結合Non usage-based pricing、Usage-based pricing、Static pricing和Dynamic pricing的優點以及DiffServ (Differentiated Services)劃分服務等級(service level)的機制，實際設計出使用者效用函數(utility function)與網路成本函數(cost function)，並以分級訂價方式訂定價格。藉著價格機能，讓使用者表達其對服務等級的需求或期望，並使網路資源適當地分配給各種服務，避免資源浪費或錯置的情形，以符合QoS的需求並提高整體社會福利及增加廠商收益。 / The issue of QoS is getting more and more important in the future integration of heterogeneous networks, and the most feasible integration is UMTS and WLAN as for present network environment. In our research, we would propose the concept of pricing-improved QoS combined with the advantage of usage-based, non usage-based, static, and dynamic pricing schemes and the mechanism of differentiated service classess of DiffServ (Differentiated Services) based on the integration of UMTS and WLAN. We would propose the utility function and cost function in detail, and price by differentiated service classes. By the affection of price, a user could express the service class he actually needs and expects. Network resources would be allocated appropriately to each service class avoiding the inappropriate allocation and wastage. This would meet the requirement of QoS and improve the providers’ revenue and overall social welfare.