Back-haul infrastructures of today's wireless operators must support the triple-play services demanded by the market or regulatory bodies. To cope with increasing capacity demand, the EU FP7 project CARMEN has developed a cost-effective heterogeneous multi-radio wireless back-haul architecture, which may also leverage the native multicast capabilities of broadcast technologies such as DVB-T to off-load high-bandwidth broadcast content delivery. However, the integration of such unidirectional technologies into a packet-switched architecture requires careful considerations. The contribution of this thesis is the investigation, design and evaluation of protocols and mechanisms facilitating the integration of such unidirectional technologies into the wireless back-haul architecture so that they can be configured and utilized by the spectrum and capacity optimization modules. This integration mainly concerns the control plane and, in particular, the aspects related to resource and capability descriptions, neighborhood, link and Multi Protocol Label Switching (MPLS) Label-Switched Path (LSP) monitoring, unicast and multicast LSP signalling as well as topology forming and maintenance. During the course of this study we have analyzed the problem space, proposed solutions to the resulting research questions and evaluated our approach. Our results show that the now Unidirectional Technology (UDT)-aware architecture can readily consider Unidirectional Technologies (UDTs) to distribute, for example, broadcast content.

Cette thèse porte sur les aspects de conception d'un synthétiseur de fréquence pour les émetteurs-récepteurs dans les architectures multi-radios cognitives. La largeur de bande couverte par ce synthétiseur multi-radio correspond à la bande de fréquences des normes de communication sans fil les plus diffusées, fonctionnant dans la bande de fréquence de 800 MHz à 6 GHz. Du fait que l'opération multi-standard est indispensable, le synthétiseur doit répondre aux exigences les plus strictes et parfois contradictoires. Compte tenu de ces exigences, une nouvelle approche pour une synthèse de fréquence multi-mode a été conçue. Un synthétiseur de fréquence hybride, basé sur le principe de la boucle à verrouillage de phase a été proposé et un nouveau protocole de commutation a été présenté et validé sur une carte d'évaluation expérimentale. Cette approche combine les modes fractionnel et entier avec une topologie de filtre à bande commuté. Par rapport aux techniques standard, la configuration hybride permet une grande souplesse en matière de reconfiguration et d'ailleurs, elle offre une complexité des circuits relativement faible ainsi qu'une faible consommation électrique. Cette architecture assure la reconfiguration de la bande passante de la boucle ainsi que la résolution, le niveau du bruit de phase et du temps d'accrochage et, par conséquent, elle peut s'adapter à des besoins divers, imposés par les normes concernées. Des analyses correspondantes, des simulations et des mesures ont été réalisées afin de vérifier les performances et les fonctionnalités de la solution proposée. A part la conception du synthétiseur de fréquence multi-radio, une campagne de mesures régionales de l'utilisation du spectre radio a été réalisée dans le cadre de la recherche de cette thèse. Ces mesures sont fondées sur le principe de détection de l'énergie et nous démontrent le degré d'utilisation du spectre radio dans les différentes régions, notamment dans la ville de Brno en République Tchèque et dans la ville de Paris et sa banlieue en France. L'objectif de cette campagne de mesures expérimentales a été d'estimer le degré d'utilisation du spectre radio dans des environnements différents et de souligner le fait qu'une nouvelle approche pour la gestion du spectre radio est inévitable / This doctoral thesis deals with design aspects of a reconfigurable frequency synthesizer for flexible radio transceivers in future cognitive multi-radios. The frequency bandwidth to be covered by this multi-radio synthesizer corresponds to the frequency bands of the most diffused wireless communication standards in the frequency band 800 MHz to 6 GHz. Since multi-standard operation is required, the synthesizer must fulfil the most stringent and sometimes conflicting requirements. Given these requirements, a novel approach for multi-mode frequency synthesis has been conceived. A hybrid phase locked loop based frequency synthesizer has been proposed and a novel switching protocol has been presented and validated on an experimental evaluation board. This approach combines fractional-N and integer-N modes of operation with switched loop filter topology. Compared to standard PLL techniques, the hybrid configuration provides a great flexibility in terms of reconfiguration and moreover, it offers relatively low circuit complexity and low power consumption. This architecture provides reconfiguration of the loop bandwidth, frequency resolution, phase noise and settling time performance and hence, it can adapt itself to diverse requirements given by the concerned wireless communication standards. Corresponding analyses, simulations and measurements have been carried out in order to verify the performance and functionality of the proposed solution. A part from the design of the multiband frequency synthesizer, a set of regional measurements of the radio spectrum utilization has been carried out in the framework of this dissertation research. These measurements are based on the energy detection principle and provide a close look at the degree of radio spectrum utilization in different regions, namely in the city of Brno in the Czech Republic and in the city of Paris and one of its suburbs in France. The goal of the experimental measurement campaign has been to estimate the degree of radio spectrum usage in a particular environment and to point out the fact that a new approach for radio spectrum management is inevitable

This thesis addresses the problem of `efficient' broadcast in a multi-radio multi-channel multi-rate wireless mesh network (MR$^2$-MC WMN). In such a MR$^2$-MC WMN, nodes are equipped with multiple radio network interface cards, each tuned to an orthogonal channel, that can dynamically adjust transmission rate by choosing a modulation scheme appropriate for the channel conditions. We choose `broadcast latency', defined as the maximum delay between a packet's network-wide broadcast at the source and its eventual reception at all network nodes, as the `efficiency' metric of broadcast performance. The problem of constructing a broadcast forwarding structure having minimal broadcast latency is referred to as the `minimum-latency-broadcasting' (MLB) problem. While previous research for broadcast in single-radio single-rate wireless networks has highlighted the wireless medium's `\emph{wireless broadcast advantage}' (WBA); little is known regarding how the new features of MR$^2$-MC WMN may be exploited. We study in this thesis how the availability of multiple radio interfaces (tuned to orthogonal channels) at WMN nodes, and WMN's multi-rate transmission capability and WBA, might be exploited to improve the `broadcast latency' performance. We show the MLB problem for MR$^2$-MC WMN to be NP-hard, and resort to heuristics for its solution. We divide the overall problem into two sub-problems, which we address in two separate parts of this thesis. \emph{In the first part of this thesis}, the MLB problem is defined for the case of single-radio single-channel multi-rate WMNs where WMN nodes are equipped with a single radio tuned to a common channel. \emph{In the second part of this thesis}, the MLB problem is defined for MR$^2$-MC WMNs where WMN nodes are equipped with multiple radios tuned to multiple orthogonal channels. We demonstrate that broadcasting in multi-rate WMNs is significantly different to broadcasting in single-rate WMNs, and that broadcast performance in multi-rate WMNs can be significantly improved by exploiting the availability of multi-rate feature and multiple interfaces. We also present two alternative MLB broadcast frameworks and specific algorithms, centralized and distributed, for each framework that can exploit multiple interfaces at a WMN node, and the multi-rate feature and WBA of MR$^2$-MC WMN to return improved `broadcast latency' performance.

No description available.

La présence importante de plusieurs réseaux sans-fils de différentes portées a encouragée le développement d’une nouvelle génération d’équipements portables sans-fils avec plusieurs interfaces radio. Ainsi, les utilisateurs peuvent bénéficier d’une large possibilité de connectivité aux réseaux sans-fils (e.g. Wi-Fi [1], WiMAX [2], 3G [3]) disponibles autour. Cependant, la batterie d’un nœud mobile à plusieurs interfaces sera rapidement épuisée et le temps d’utilisation de l’équipement sera réduit aussi. Pour prolonger l’utilisation du mobile les standards, des réseaux sans-fils, on définie (individuellement) plusieurs états (émission, réception, sleep, idle, etc.); quand une interface radio n’est pas en mode émission/réception il est en mode sleep/idle où la consommation est très faible, comparée aux modes émission/réception. Pourtant, en cas d’équipement portable à multi-interfaces radio, l’énergie totale consommée par les interfaces en mode idle est très importante. Autrement, un équipement portable équipé de plusieurs interfaces radio augmente sa capacité de connectivité mais réduit sa longévité d’utilisation. Pour surpasser cet inconvénient on propose une plate-forme, qu'on appelle IMIP (Integrated Management of Interface Power), basée sur l’extension du standard MIH (Media Independent Handover) IEEE 802.21 [4]. IMIP permet une meilleure gestion d’énergie des interfaces radio, d’un équipement mobile à multi-radio, lorsque celles-ci entrent en mode idle. Les expérimentations que nous avons exécutées montrent que l’utilisation de IMIP permet d'économiser jusqu'a 80% de l'énergie consommée en comparaison avec les standards existants. En effet, IMIP permet de prolonger la durée d'utilisation d'équipements à plusieurs interfaces grâce à sa gestion efficace de l'énergie. / The large availability of wireless networks of different ranges, has contributed to the development of new generation of handheld devices with multi-radio interfaces. Thus, the end-users are able to achieve ubiquitous and seamless connectivity across heterogeneous wireless networks (e.g., Wi-Fi [1], WiMAX [2] and 3G_LTE [3]). However, a mobile node with multi-radio interfaces has its battery energy consumed rapidly, which reduces the operation/usage time of the device. To improve battery usage, wireless network standards have defined (individually) different interface states (transmit, receive, idle, sleep, etc.); when an interface is not transmitting or receiving, it goes to sleep/idle state where energy consumption is very low compared to transmit and receive states. However, in the case of multi-radio handheld devices, the total energy consumed by the interfaces in sleep/idle state is significant. Thus, equipping a mobile device with multiple interfaces increases its seamless connectivity but reduces its operation/usage longevity. To overcome this inconvenient, we proposed a framework, called IMIP (Integrated Management of Interface Power) that consists of an extension of MIH (Media Independent Handover) IEEE 802.21 standard [4]. IMIP allows a better power management of radio interfaces of a multi-radio mobile node; indeed, it reduces considerably energy consumption. The basic idea behind IMIP is to shut down any interface in idle mode and use a proxy that emulates the interface; the proxy wakes up the interface when it receives a connection request directed to this interface. IMIP requires at least one interface in active mode. Experiments show that using IMIP enables a saving of up to 80% of power consumption compared with existing power management standards. Thus, IMIP allows longer usage of multiple interface devices thanks to its effective energy management.

This thesis addresses the problem of `efficient' broadcast in a multi-radio multi-channel multi-rate wireless mesh network (MR$^2$-MC WMN). In such a MR$^2$-MC WMN, nodes are equipped with multiple radio network interface cards, each tuned to an orthogonal channel, that can dynamically adjust transmission rate by choosing a modulation scheme appropriate for the channel conditions. We choose `broadcast latency', defined as the maximum delay between a packet's network-wide broadcast at the source and its eventual reception at all network nodes, as the `efficiency' metric of broadcast performance. The problem of constructing a broadcast forwarding structure having minimal broadcast latency is referred to as the `minimum-latency-broadcasting' (MLB) problem. While previous research for broadcast in single-radio single-rate wireless networks has highlighted the wireless medium's `\emph{wireless broadcast advantage}' (WBA); little is known regarding how the new features of MR$^2$-MC WMN may be exploited. We study in this thesis how the availability of multiple radio interfaces (tuned to orthogonal channels) at WMN nodes, and WMN's multi-rate transmission capability and WBA, might be exploited to improve the `broadcast latency' performance. We show the MLB problem for MR$^2$-MC WMN to be NP-hard, and resort to heuristics for its solution. We divide the overall problem into two sub-problems, which we address in two separate parts of this thesis. \emph{In the first part of this thesis}, the MLB problem is defined for the case of single-radio single-channel multi-rate WMNs where WMN nodes are equipped with a single radio tuned to a common channel. \emph{In the second part of this thesis}, the MLB problem is defined for MR$^2$-MC WMNs where WMN nodes are equipped with multiple radios tuned to multiple orthogonal channels. We demonstrate that broadcasting in multi-rate WMNs is significantly different to broadcasting in single-rate WMNs, and that broadcast performance in multi-rate WMNs can be significantly improved by exploiting the availability of multi-rate feature and multiple interfaces. We also present two alternative MLB broadcast frameworks and specific algorithms, centralized and distributed, for each framework that can exploit multiple interfaces at a WMN node, and the multi-rate feature and WBA of MR$^2$-MC WMN to return improved `broadcast latency' performance.

No description available.

A wireless channel is shared by all devices, in the vicinity, that are tuned to the channel, and at any given time, only one of the devices can transmit information. One way to overcome this limitation, in throughput capacity, is to use multiple orthogonal channels for different devices, that want to transmit information at the same time. In this work, we consider the use of multiple orthogonal channels in wireless data networks. We explore algorithms and protocols for such multi-channel wireless networks under two broad categories of network-wide and link-level challenges. Towards handling the network-wide issues, we consider the channel assignment and routing issues in multi-channel wireless networks. We study both single radio and multi-radio multi-channel networks. For single radio multi-channel networks, we propose a new granularity for channel assignment, that we refer to as component level channel assignment. The strategy is relatively simple, and is characterized by several impressive practical advantages. For multi-radio multi-channel networks, we propose a joint routing and channel assignment protocol, known as Lattice Routing. The protocol manages channels of the radios, for the different nodes in the network, using information about current channel conditions, and adapts itself to varying traffic patterns, in order to efficiently use the multiple channels. Through ns2 based simulations, we show how both the protocols outperform other existing protocols for multi-channel networks under different network environments. Towards handling the link-level challenges, we identify the practical challenges in achieving a high data-rate wireless link across two devices using multiple off-the-shelf wireless radios. Given that the IEEE 802.11 a/g standards define 3 orthogonal wi-fi channels in the 2.4GHz band and 12 orthogonal wi-fi channels in the 5GHz band, we answer the following question: ``can a pair of devices each equipped with 15 wi-fi radios use all the available orthogonal channels to achieve a high data-rate link operating at 600Mbps?' Surprisingly, we find through experimental evaluation that the actual observed performance when using all fifteen orthogonal channels between two devices is a mere 91Mbps. We identify the reasons behind the low performance and present Glia, a software only solution that effectively exercises all available radios. We prototype Glia and show using experimental evaluations that Glia helps achieve close to 600Mbps data-rate when using all possible wi-fi channels.

This doctoral thesis deals with design aspects of a reconfigurable frequency synthesizer for flexible radio transceivers in future cognitive multi-radios. The frequency bandwidth to be covered by this multi-radio synthesizer corresponds to the frequency bands of the most diffused wireless communication standards in the frequency band 800 MHz to 6 GHz. Since multi-standard operation is required, the synthesizer must fulfil the most stringent and sometimes conflicting requirements. Given these requirements, a novel approach for multi-mode frequency synthesis has been conceived. A hybrid phase locked loop based frequency synthesizer has been proposed and a novel switching protocol has been presented and validated on an experimental evaluation board. This approach combines fractional-N and integer-N modes of operation with switched loop filter topology. Compared to standard PLL techniques, the hybrid configuration provides a great flexibility in terms of reconfiguration and moreover, it offers relatively low circuit complexity and low power consumption. This architecture provides reconfiguration of the loop bandwidth, frequency resolution, phase noise and settling time performance and hence, it can adapt itself to diverse requirements given by the concerned wireless communication standards. Corresponding analyses, simulations and measurements have been carried out in order to verify the performance and functionality of the proposed solution. A part from the design of the multiband frequency synthesizer, a set of regional measurements of the radio spectrum utilization has been carried out in the framework of this dissertation research. These measurements are based on the energy detection principle and provide a close look at the degree of radio spectrum utilization in different regions, namely in the city of Brno in the Czech Republic and in the city of Paris and one of its suburbs in France. The goal of the experimental measurement campaign has been to estimate the degree of radio spectrum usage in a particular environment and to point out the fact that a new approach for radio spectrum management is inevitable

Cette thèse porte sur les architectures d’émission pour des terminaux mobiles multi-radio fonctionnant dans la bande de fréquences, 800 MHz - 6 GHz. Avec l’évolution constante des systèmes de communication, les terminaux doivent fonctionner dans plusieurs bandes de fréquences et modes, correspondant à une grande diversité de normes. Le concept d’une architecture multi-radio unique est une évolution de celui de l’émetteur-récepteur multistandard, caractérisé par une mise en parallèle des circuits pour chaque standard. Il permet alors d’optimiser coût et consommation. L’objet de l’étude est de concevoir des architectures d’émission flexibles, à la fois en fréquence et en format de modulation, capables de générer les formes d’ondes de tous les standards en respectant pour chacun le niveau de puissance en sortie et assurant un bon rendement. Ce type d’architectures pourrait, dans l’avenir, être utilisé pour des applications de radio cognitive. L’amplificateur de puissance est l’élément critique dans les émetteurs. Le principe de fonctionnement des amplificateurs impose un compromis entre la linéarité et le rendement en puissance. L’utilisation des amplificateurs en classes commutées permet d’améliorer les performances en rendement mais nécessite de revoir complètement les architectures classiques d’émission. Dans ce contexte, plusieurs architectures qui transforment les signaux avant l’amplificateur et qui peuvent être utilisées pour la multi-radio ont été considérées. Trois, en particulier, ont été analysées et comparées ; à savoir : l’architecture polaire avec codeur d’enveloppe sigma-delta, l’architecture polaire avec codeur d’enveloppe par largeur d’impulsion et l’architecture cartésienne sigma-delta. La validation a été faite sur les signaux les plus critiques en matière de dynamique de puissance et de bande passante, que sont les signaux LTE et WiMAX mobile. En sortie de l’amplificateur, le filtrage d’émission joue un rôle décisif et plusieurs technologies de filtrage sont envisageables. Dans ce cadre, on s’est plus particulièrement intéressé à la technologie BAW (Bulk Acoustic Wave) et un banc de filtres multi-radio a été synthétisé. Cette thèse a donc permis de chiffrer les performances clés d’un émetteur multi-radio à haut rendement en analysant du traitement en bande de base jusqu’au filtrage d’antenne / This research deals with wireless multi-radio transmitter architectures operating in the frequency band of 800 MHz – 6GHz. As a consequence of the constant evolution in the communication systems, the mobile transmitters must be able to operate at different frequency bands and modes according to existing standards specifications. The concept of a unique multi-radio architecture is an evolution of the multi-standard transceiver characterized by a parallelization of circuits for each standard. Multi-radio concept optimizes surface and power consumption. This study concentrates on flexible multi-radio architectures. This kind of architectures could be used in the future for cognitive radio applications. The power amplifier (PA) is the key element in transmitter architectures. Its operating principle establishes a trade-off between power efficiency and linearity. The utilization of a switched mode amplifier allows improving efficiency performances but implies a review of the classical transmitter architectures. Within this context, some architectures transforming the input signal of the PA and that are candidates for multi-radio applications are considered. In particular, three architectures have been analyzed and compared: the polar architecture with sigma-delta envelope modulator, the polar architecture with pulse width modulator and the cartesian sigma delta architecture. Validation is accomplished with the most critical signals in terms of power dynamics and frequency bandwidth; these are the LTE and mobile WiMAX. At the amplifier output, the band-pass filter plays a key role and many filtering technologies could be envisaged. In particular, we are interested in the BAW technology (Bulk Acoustic Wave) and a filter bank has been synthesized. This research has quantified the key performances of a high efficiency multi-radio transmitter by analyzing the system from baseband signal treatment to RF filtering before the antenna