Dans cette thèse, nous enrichissons et appliquons la théorie des processus de Poisson spatiaux pour résoudre certains problèmes issus de la conception et du déploiement des réseaux cellulaire. Cette thèse comporte deux parties principales. La première partie est consacrée à la résolution de quelques problèmes de dimensionnement et de couverture des réseaux cellulaires. Nous calculons la probabilité de surcharge de systèmes OFDMA grâce aux inégalités de concentration et aux développements d'Edgeworth, pour lesquels nous prouvons des bornes d'erreur explicites, et nous l'appliquons à résoudre un problème de dimensionnement. Nous calculons également la probabilité d'outage et le taux de handover pour un utilisateur typique. La seconde partie est consacrée à l'étude de différents modèles pour la consommation d'énergie dans les réseaux cellulaires. Dans le premier modèle, l'emplacement initial des utilisateurs forme un processus de Poisson ponctuel et à chaque utilisateur est associé un processus d'activité de type ON-OFF. Dans le second modèle, l'arrivée des utilisateurs constitue un processus de Poisson en espace et en temps, une dynamique connue sous le nom de dynamique de Glauber. Nous étudions également l'impact de la mobilité des utilisateurs en supposant que les utilisateurs se déplacent de manière aléatoire pendant leur séjour. Nous nous intéressons dans toutes ces situations, à la distribution de l'énergie consommée par une station de base. Cette énergie est divisée en deux parties: la partie additive et la partie diffusive. Nous obtenons des expressions analytiques pour les moments de la partie additive ainsi que la moyenne et la variance de l'énergie totale consommée. Nous trouvons une borne d'erreur pour l'approximation gaussienne de la partie additive. Nous prouvons que la mobilité des utilisateurs a un impact positif sur la consommation d'énergie. Il n'augmente ni ne réduit l'énergie consommée en moyenne, mais réduit sa variance à $0$ en régime de mobilité élevé. Nous caractérisons aussi le taux de convergence en fonction de la vitesse des utilisateurs. / Nowadays, cellular technology is almost everywhere. It has had an explosive success over the last two decades and the volume of traffic will still increase in the near future. For this reason, it is also regarded as one cause of worldwide energy consumption, with high impact on carbon dioxide emission. On the other hand, new mathematical tools have enabled theconception of new models for cellular networks: one of these tools is stochastic geometry, or more particularly spatial Poisson point process. In the last decade, researchers have successfully used stochastic geometry to quantify outage probability, throughput or coverage of cellular networks by treating deployment of mobile stations or (and) base stations as Poisson point processes on a plane. These results also take into account to impact of mobility on the performance of such networks. In this thesis, we apply the theory of Poisson point process to solve some problems of cellular networks, in particular we analyze the energy consumption of cellular networks. This thesis has two main parts. The first part deals with some dimensioning and coverage problems in cellular network. We uses stochastic analysis to provide bounds for theoverload probability of OFDMA systems thanks to concentration inequalities and we apply it to solve a dimensioning problem. We also compute the outage probability and handover probability of a typical user. The second part is dedicated to introduce different models for energy consumption of cellular networks. In the first model, the initial location of users form a \PPP\ and each user is associated with an ON-OFF process of activity. In the second model, arrival of users forms a time-space \PPP. We also study the impact of mobility of users by assuming that users randomly move during its sojourn. We focus on the distribution of consumed energy by a base station. This consumed energy is divided into the additive part and the broadcast part. We obtain analytical expressions for the moments of the additive part as well as the mean and variance of the consumed energy. We are able to find an error bound for Gaussian approximation of the additive part. We prove that the mobility of users has a positive impact on the energy consumption. It does not increase or decrease the consumed energy in average but reduces its variance to zero in high mobility regime. We also characterize the convergent rate in function of user's speed.

No description available.

Modern cellular networks including LTE (Long Term Evolution) and the evolving LTE- Advanced provide high-speed and high-capacity data services for mobile users. As we become more reliant on wireless connectivity, the security of voice and data transmissions on the network becomes increasingly important. While the LTE network standards provide strict security guidelines, these requirements may not be completely followed when LTE networks are deployed in practice. This project provides a method for improving the security of LTE networks by 1) characterizing a gap between security requirements defined in the standards and practical implementations, 2) designing a language to express the encoding formats of one of LTE’s network-layer protocols, 3) developing a compiler to translate a protocol description in our language into an implementation, and 4) providing recommendations on lessons learned during development of the language and compiler to support development of future protocols that employ formal representations. In this way, our work demonstrates how a formal language can be utilized to represent a cellular network protocol and serves as an example for further research on how adding formalism to network standards can help ensure that the security goals defined in the standards can be upheld in an implementation.

With a fixed number of terminals and a fixed system spectrum, it can be shown that increasing the number of BSs in a cellular network results in a better network performance. However, a regular organized deployment of a cellular network with small cells is both prohibitively expensive and complicated. A possible solution is to allow the network to grow in an organic fashion. This calls for self-configurable approaches for resource allocation which not only improve the performance but also decrease the network planning as well as maintenance costs. Over the past few years, a particular type of small BSs known as femto-BSs has attracted tremendous attention from the industry and academia alike. Femto BSs operate on the licensed spectrum allocated to the cellular network. They are small, inexpensive and transmit at low power levels. Although the deployment of these small BSs result in significant improvements in the indoor coverage for both voice and data services, they only satisfy the immediate needs of the present cellular networks — namely the improvement of the indoor coverage. They do not provide a fundamental solution for a scalable architecture which can organically grow and adapt to the short and long term changes in the network. In this thesis, we propose a practical unified framework for the system design and resource allocation of cellular networks with various types of base stations (with different power budgets) deployed in an irregular fashion. We refer to these networks as autonomous cellular networks. To this end, we first introduce an adaptive localized approach to resource allocation in traditional cellular networks. We show that localized resource assignment at the cost of partial loss of orthogonality at the cell edges can provide significant gains in the network performance. In the second part of the thesis, we propose an adaptive self-configurable resource allocation framework for cellular networks. A network clustering technique is proposed which enables coordinated resource allocation in a network with irregular deployment of BSs. The performance of the proposed framework is evaluated with the regular as well as the irregular deployment of BSs.

With a fixed number of terminals and a fixed system spectrum, it can be shown that increasing the number of BSs in a cellular network results in a better network performance. However, a regular organized deployment of a cellular network with small cells is both prohibitively expensive and complicated. A possible solution is to allow the network to grow in an organic fashion. This calls for self-configurable approaches for resource allocation which not only improve the performance but also decrease the network planning as well as maintenance costs. Over the past few years, a particular type of small BSs known as femto-BSs has attracted tremendous attention from the industry and academia alike. Femto BSs operate on the licensed spectrum allocated to the cellular network. They are small, inexpensive and transmit at low power levels. Although the deployment of these small BSs result in significant improvements in the indoor coverage for both voice and data services, they only satisfy the immediate needs of the present cellular networks — namely the improvement of the indoor coverage. They do not provide a fundamental solution for a scalable architecture which can organically grow and adapt to the short and long term changes in the network. In this thesis, we propose a practical unified framework for the system design and resource allocation of cellular networks with various types of base stations (with different power budgets) deployed in an irregular fashion. We refer to these networks as autonomous cellular networks. To this end, we first introduce an adaptive localized approach to resource allocation in traditional cellular networks. We show that localized resource assignment at the cost of partial loss of orthogonality at the cell edges can provide significant gains in the network performance. In the second part of the thesis, we propose an adaptive self-configurable resource allocation framework for cellular networks. A network clustering technique is proposed which enables coordinated resource allocation in a network with irregular deployment of BSs. The performance of the proposed framework is evaluated with the regular as well as the irregular deployment of BSs.

No description available.

ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California / This paper presents a method for managing a Mixed Network with multiple ground stations and Test Articles (TA) preferences. The main difference between a Ground Station (cellular) network and the over the horizon (ad-hoc) network is that the ad-hoc method has no fixed infrastructure. This paper presents the computation and performance of a clustering technique for mobile nodes within the simulated mixed network environment with multiple ground stations and users preferences for those ground stations. This includes organization for multiple ground stations and for TA's gravitating toward a ground station of their choice on the basis of service and performance.

There is a trend to move the frequency band for wireless transmission to ever higher frequencies in the radio frequency (RF) spectrum to fulfil the exponentially increasing demand in wireless communication capacity. Research work has gone into improving the spectral efficiency of wireless communication system to use the scarce and expensive resources in the most efficient way. However, to make wireless communication future-proof, it is essential to explore ways to transmit wirelessly outside the traditional RF spectrum. The visible light (VL) spectrum bandwidth is 1000 times wider than the entire 300 GHz RF spectrum and is, therefore, a viable alternative. Visible light communication (VLC) enables existing lighting infrastructures to provide not only illumination but also wireless communication. In conjunction with the concept of cell densification, a networked VLC system, light fidelity attocell (LAC) network, has been proposed to offer wide coverage and high speed wireless data transmission. In this study, many issues related to the downlink system in LAC networks have been investigated. When analysing the downlink performance of LAC networks, a large number of random channel samples are required for the empirical calculation of some system metrics, such as the signal-to-interference-plus-noise ratio (SINR). However, using state-of-the-art approaches to calculate the non-line-of-sight (NLoS) channel component leads to significant computational complexity and prolonged computation time. An analytical method has been presented in this thesis to efficiently calculate the NLoS channel impulse response (CIR) in VLC systems. The results show that the proposed method offers significant reduction in computation time compared to the state-of-the-art approaches. A comprehensive performance evaluation of the downlink system of LAC networks is carried out in this thesis. Based on the research results in the literature in the field of optical wireless communication (OWC), a system level framework for the downlink system in LAC networks is developed. By using this framework, the downlink performance subject to a large number of parameters is evaluated. Additionally, the effect of varying network size, cell deployment and key system parameters are investigated. The calculation of downlink SINR statistics, cell data rate and outage probability are considered and analysed. The results show that the downlink performance of LAC networks is promising in terms of achievable data rate per unit area compared to other state-of-the-art RF small-cell networks. It is found that co-channel interference (CCI) is a major source of signal impairment in the downlink of LAC network. In order to mitigate the influence of CCI on signal distortion in LAC networks, widely used interference mitigation techniques for RF cellular systems are borrowed and extensively investigated. In this study, fractional frequency reuse (FFR) is adapted to the downlink of LAC networks. The SINR statistics and the spectral efficiency in LAC downlink system with FFR schemes are evaluated. Results show that the FFR technique can greatly improve the performance of cell edge users and as well the overall spectral efficiency. Further performance improvements can be achieved by incorporating angular diversity transmitters (ADTs) with FFR and coordinated multi-point joint transmission (JT) techniques.

The rapid evolution of current and upcoming high speed and complex communications networks often necessitates flawless time synchronization among the network nodes in order to guarantee performance. GPS based synchronizers have long been used for synchronizing telecommunications equipment, currently providing an accuracy of up to 10ns. Such high accuracy demands excellent operation from GPS timing receivers. Interference is an important threat to GPS performance. Any degradation in performance, due to the introduction of interference, can cause these receivers to provide a low quality timing solution, or to lose lock with incoming GPS signals altogether. This consideration motivates the study of the performance of GPS timing receivers in the presence of harmful interference. This work is devoted to the theoretical and practical investigations of the effects of RF interference on GPS-based synchronizers and their impacts on communications networks. Contributions made during this work include: a) Identification of the processes and the parameters involved in producing a timing solution which are vulnerable to interference; b) experimentbased confirmation of a hypothesis about the effects of interference on GPS timing receivers; c) identification of the effects of degraded synchronization on the performance of communications networks, especially CDMA and GSM cellular networks, which rely upon GPS based synchronizers; and d) proposal of a method to predict and avoid communications network performance degradation.

With the progress of wireless radio technology and telecommunication, various wireless specifications and protocols form the unhandy heterogeneous network. The routing problems in heterogeneous network become popular researches nowadays. In this thesis, we integrate cellular (3G) network and Mobile Ad-Hoc Network (MANET) into a hybrid network. This hybrid network is called heterogeneous wireless network(HWN) with multi-cells architecture to overcome the weakness of cellular network and Ad-Hoc network. Based on HWN, we propose a routing algorithm with quality of service (QoS) supported for requirements in the original homogeneous cellular network and Ad-Hoc network. Simulation results show that HWN with the proposed algorithm has lower request block rate and shorter transmission time.