Écosystèmes de télécommunications seront composés, dans le futur, de plusieurs réseaux hétérogènes, réseaux sans fil et réseaux cellulaires, et un terminal d’utilisateur qui est capable de se connecter et de se communiquer à travers ces réseaux. Cette thèse contribue pour l’évolution de convergence dans les réseaux hétérogènes sans fil ainsi que de proposer des nouveaux mécanismes afin de permettre de délai bas pendant le « handover » au niveau de l’authentification en utilisant la sélection de réseau, l’administration de sécurité et la mobilité dans les futurs écosystèmes de télécommunications pour permettre un accès ubiquité à Internet et aussi à des services en cas de mobilité. Cet accès doit être disponible tout le temps et partout en assurant le bon niveau de sécurité pour les utilisateurs ainsi que pour les réseaux. Un objectif principal de cette thèse est de définir des mécanismes pour « seamless secured roaming » afin que les abonnés ou les utilisateurs soient capable de se promener entre différents réseaux d’accès qui implémente des technologies et des mécanismes d’accès similaires. La thèse présentée propose une solution de roaming et interopérabilité en utilisant des entités intermédiaires qu’on appelle « Roaming Interworking Intermediary (RII) ». Ces entités permettent un « handover » sûr à travers des différents systèmes d’accès et différents opérateurs sans interruption de service. RII agit comme un agent dans l'architecture RII entre le réseau d’origine et le réseau d'opérateur visité. RII permet l'administration de la mobilité, le transfert entre les fournisseurs de service, l'architecture de sécurité pour l'authentification et les associations d'utilisateurs en parcourant, aussi l’administration de réseau et de présence. Cette thèse définit, aussi, des nouveaux mécanismes qui permettent des délais bas pendant les « handovers » et « roaming » en optimisant et présentant des nouveaux modèles d’authentification et de mobilité (post hanover techniques) dans les réseaux hétérogènes. Nous avons présenté de nouvelles méthodes afin de résoudre le problème de longues périodes d'identité d'utilisateur et de routage des informations d'authentification d'utilisateur dans les réseaux d’accès visités avec ou sans SLA direct avec le réseau d’origine. Nous avons développé un modèle d’authentification dynamique en utilisant l’architecture de RII proposé, où un utilisateur ou un abonné est authentifiés au réseau de visite sans besoin de router des informations authentiques aux réseaux d’origine. Cette thèse propose aussi des nouveaux mécanismes de mobilité basés sur « Proxy IP Mobile » et étend l'infrastructure d'AAA pour obtenir des délais très bas pendant le « handover » dans les réseaux WLAN, WIMAX et 3G. Des études comparatives, entre les modèles proposés et existants, concernant l'authentification et la mobilité sont effectuées à travers des plate-forme réelles. La thèse propose aussi des techniques pré-hanover dans les réseaux hétérogènes pour garantir « seamless handover » pendant la mobilité et le « roaming ». Cette approche est une approche focalisée réseau où les réseaux d’accès contrôlent tous les procédures comme la sélection de réseau, la sécurité, la mobilité etc … avec l'aide des terminaux mobiles et des réseaux de visite. Donc, de nouveaux modèles pour la sélection de réseau basés sur la prédiction, l'administration de sécurité pour les authentifications, et des modèles de mobilité sont proposés dans cette thèse. De nouveaux protocoles et des extensions pour le protocole existant afin d’accomplir le « seamless handover » sont proposés dans ce travail. Une plate-forme réelle et complète était construite avec l'implémentation des protocoles proposés pour évaluer l'efficacité des mécanismes proposés. / The future telecom ecosystem will be composed by a set of heterogeneous wireless and cellular networks and user terminal capable to connect and communicate with any of these networks. This thesis contributes for evolution of convergence of wireless heterogeneous networks and to propose novel mechanisms to support low latency handover at authentication level using network selection, security context management and mobility in future telecom ecosystem to allow ubiquitous access to the Internet and services to any individual on the move. This access should be possible anytime anywhere while ensuring the right level of security to the end users as well to the networks. One main objective of the thesis is to define seamless secured roaming mechanisms to enable subscribers or users to roam along different access networks indifferent of access technologies, operators and accessing mechanisms. The proposed thesis provides a roaming & interworking solution using intermediary entity, called Roaming Interworking Intermediary (RII), which enable the secure handover across different access systems and different operator domains without service interruption. RII acts like a broker in the RII architecture between home and visited operator networks. RII provides mobility management, context transfer between service providers, security architecture for authentication and associations of users while roaming, network and presence management. The thesis also defines new mechanisms to enable low latency during handovers and roaming by optimizing and introducing new authentication and mobility models (post handover techniques) in heterogeneous networks. We have provided new methods to solve ever longing issue of user identity and routing of user authentication information from visiting access networks with or without a direct SLA with the home network. We have introduced dynamic authentication model with the proposed RII architecture where a user or subscriber gets authenticated at the visiting network without re-routing authentication information to home networks. The thesis also propose a new mobility mechanisms based on Proxy Mobile IP and extending AAA infrastructure to obtain very low latency during handover in WLAN, WIMAX and 3G networks. Testbeds and comparative studies between proposed and existing models for authentication and mobility are provided. This thesis also provides novel pre handover techniques in heterogeneous networks to ensure seamless handover during mobility and roaming. This method is a network centric approach where the access networks controls whole procedures of network selection, security, mobility etc… with the help of mobile terminals and visiting networks. Therefore, new models for location prediction based Network selection, security context management for authentications, context based mobility models are proposed in this thesis. New supporting protocols and extensions of existing protocol to achieve seamless handovers are proposed in this work. A full testbed is built with the implementation of the proposed protocols to evaluate the proposed of the efficiency of the proposed mechanisms.

I den här rapporten redovisas resultatet av de mätningar som gjorts av Telias 4G-nät i form av datahastighet och signalstyrka, inom området av Umeå universitets Campus. Rapporten innefattar även en grundläggande teoretiskt beskrivning av de system och tekniker som berör ett 4G-nät. Mätningen utgick från 304 punkter över Campus området, mätningen skedde via att använda applikationen ”Bredbandskollen” på en mobiltelefon av modellen Huaweii P7-L10. En andra mätning genomfördes under ”Brännbollsyran” på Campus, från 26-28 maj. Syftet med den mätningen var att undersöka hur nätet klara av en högre belastning, och jämföra de mätvärdena mot dom tidigare. De slutsatser som dragits av rapporten är följande: Telias 4G nät lever upp till det kriterium om täckning och hastighet de själva uppgett. Mottagningen är bra på campusområdet, men inomhus kan den vara oberäknelig. Nätet klarade av belastningen under brännbollsyran, och gick fortfarande att använda bra trots hög belastning inom nätet. / This report presents the results of the mesaurements I’ve made on Telias 4G-network in the form of data rate and signal strength, withing the vicinity of Umeå University campus. This report also includes basic theoretical information about the techonolgy behind a 4G-network. The mesaurements emanated from 304 different locations around the campus area, mesaurements were made through the application ”Bredbandskollen” on a mobilephone of the model Huaweii P7-L10. A second measurement was made during the fesitval called ”Brännbollsyran” on Campus between 26-28 of may. It’s purpose was to examine how the 4G-network handled a heavier strain, and compare it’s measurements to the first one. The conclusions that have been made are the following: Telias 4G network lives up to the criteria concering coverage and speed they have stated. The reception on the campus are is good, however inside it can be unreliable. The network managed the strain during Brännbollsyran, and you could still use it sufficently, despite a heave load in the network.

The planar dual band monopole antenna is presented in this project report for Long Term Evolution (LTE). The proposed planar monopole antenna is selected because of its simple structure, cost effective components and excellent performance. The antenna operates in 3.4 GHz to 3.6 GHz and 3.6 GHz to 3.8 GHz in desired LTE frequency band. The frequency bands 3.4- 3.6 GHz and 3.6- 3.8 GHz are already available as a study of current plan according to UMTS and LTE   systems.   The designed antenna works parallel with the LTE radio access; packet core networks are also involved. A very well developed and good designed antenna relaxes the other system components and improves the performances of the whole system. For the portable application and for the multiband scenario, planar monopole is the best candidate for the proposed two bands. LTE (3.4 GHz-3.6 GHz) and LTE-Advanced (3.6 GHz-3.8 GHz) antennas are designed for portable wireless devices. Radiation pattern and operating frequency are varied according to feeding of antenna.  Return loss, radiation pattern, antenna efficiency, bandwidth and gain are important parameters of the designed antenna and are measured after simulation through CST Microwave Studio. The designed antenna is then fabricated in KTH antenna Lab.

In the past two decades, there has been a drastic increase in the mobile traffic, which is caused by the improved user experience with smart phones and its applications. In LTE system, the packet scheduler plays a vital role in the effective utilization of the resources. This field is not standardized and has immense scope of improvement, allowing vendor-specific implementation. The work presented in this thesis focuses on designing new scheduling algorithms for uplink and downlink to effectively distribute resources among the users. LTE scheduling can be categorized into two extremes, namely, Opportunistic scheduling and Fairness scheduling. The Best Channel Quality Indicator (BCQI) algorithm falls under the former category while Proportional Fairness (PF) algorithm under the later. BCQI algorithm provides high system throughput than PF algorithm, however, unlike BCQI algorithm, PF algorithm considers users with poor channel condition for allocation process. In this work, two new scheduling disciplines referred as Opportunistic Dual Metric (ODM) Scheduling Algorithm is proposed for uplink and downlink respectively. The objective of the algorithm is to prioritize the users with good channel condition for resource allocation, at the same time not to starve the users with poor channel conditions. The proposed algorithm has two resource allocation matrices, H1 and H2, where H1 is throughput-centric and H2 is fairness-centric. The uplink algorithm uses the two resource allocation matrices to allocate the resources to the users and to ensure contiguous resource allocation. The downlink algorithm is an extension of the proposed uplink algorithm avoiding uplink constraints. The downlink algorithm employs the two resource distribution matrices to provide an efficient resource allocation by expanding the allocation for the users considering intermittent resources. The performance of ODM is measured in terms of throughput, fairness. Additionally, the uplink algorithm is analysed in terms of transmit power. From the results it is observed that the proposed algorithms has better trade-off in terms of all the performance parameters than PF scheduler and BCQI scheduler.

Energy consumption has recently become a key issue from both environmental and economic considerations. A typical mobile phone network in the UK may consume approximately 40-50 MW, contributing a significant proportion of the total energy consumed by the information technology industry. With the worldwide growth in the number of mobile subscribers, the associated carbon emissions and growing energy costs are becoming a significant operational expense, leading to the need for energy reduction. The Mobile VCE Green Radio Project has been launched, which targets to achieve 100x energy reduction of the current wireless networks by 2020. In this thesis, energy-efficient resource allocation strategies have been investigated taking the LTE system as an example. Firstly, theoretical analysis of energy-efficient design in cellular environments is provided according to the Shannon Theory. Based on a two-link scenario the performance of simultaneous transmission and orthogonal transmission for network power minimization under the specified rate constraints is investigated. It is found that simultaneous transmission consumes less power than orthogonal transmission close to the base station, but much more power in the cell-edge area. Also, simulation results suggest that the energy-efficient switching margins between these two schemes are dominated by the sum total of their required data rates. New definitions of power-utility and fairness metrics are further proposed, following by the design of weighted resource allocation approaches based on efficiency-fairness trade-offs. Apart from energy-efficient multiple access between different links, the energy used by individual base stations can also be reduced. For example, deploying sleep modes is an effective approach to reduce radio base station operational energy consumption. By periodically switching off the base station transmission, or using fewer transmit antennas, the energy consumption of base station hardware may decrease. By delivering less control signalling overhead, the radio frequency energy consumption can also be reduced. Simulation results suggest that up to 90% energy reduction can be obtained in low traffic conditions by employing time-domain optimization in each radio frame. The optimum on/off duty cycle is derived, enabling the energy consumption of the base station to scale with traffic loads. In the spatial-domain, an antenna selection criterion is proposed, indicating the most energy-efficient antenna configuration with the knowledge of users’ locations and quality of service requirements. Without time-domain sleep modes, using fewer transmit antennas could outperform full antenna transmission. However, with time-domain sleep modes, using all available antennas is generally the most energy-efficient choice.

Along with higher data rates and application-enriched user terminals, LTE has even higher requirements to conserve the battery power in mobile devices compared to the WCDMA terminals. In LTE, Discontinuous Reception (DRX) has been introduced as one of the key solutions to conserve battery power in mobile terminal. It is very meaningful to investigate the possible impact of DRX on power consumption and also the VoIP performance. This study evaluates several different parameter settings for DRX, and tries to find a reasonable trade-off between VoIP performance and battery life. This study report proposes DRX parameter setting to achieve maximum possible power saving with minimum VoIP degradation. Based on the assumed power saving model and simulation scenario presented in chapter 4 and chapter 5 of this report respectively, the proposed parameter settings can achieve up to ~60% of the terminal power saving. Furthermore, it is concluded that longer DRX cycles are not suitable for VoIP traffic since they introduces longer delays and degrades the VoIP performance particularly in downlink. / This study has evaluated different DRX parameter settings for VoIP traffic both in uplink and downlink and found out different gains in terms of power saving and network performance. It is shown that key parameters include On-duration Timer, Inactivity Timer and length of DRX cycle. These three parameters have major impact on both VoIP and power saving. Different combinations of these parameters show different results. DRX affects downlink and uplink in a different manner. In the downlink, a user cannot be scheduled and thus receive any DL data during the period of inactivity. Downlink assignments can only be sent when receiving UE is awake. This is one reason that length of DRX cycle and length of On-duration period is more important parameters in downlink. It is found out that increasing the length of DRX cycle, keeping relatively constant average awake time of terminal, introduces larger delays in downlink and thus degrades the performance. On the other hand, uplink is affected by DRX only when there is fragmentation. In uplink, whenever a user has available data it can a scheduling request, which is independent of DRX state and can be sent even if UE is sleeping, and thus can get UL scheduling grant. However, if the grant is fragmented, UE might not always be able to receive remaining fragments due to DRX state. That is why Inactivity Timer plays a more important role in UL. If poor radio conditions are expected, it is important to have larger Inactivity Timer period. From the power saving point of view, the length of On-duration Timer and Inactivity Timer should be chosen as smaller as possible. However, these parameters should not be reduced below a certain threshold. For example reducing On-duration Timer below 2ms shows a major degradation in VoIP performance while not showing a comparable gain in receiver power. This study has proposed a DRX parameter setting to achieve maximum power saving with minimum VoIP degradation. Based on the assumed power saving model and the simulation settings presented in chapter 4 and chapter 5 of this report respectively, the proposed DRX settings show that ~60% of total power can be saved while keeping the VoIP capacity loss <= 12%. / This thesis is about battery saving in LTE

The interest of Machine Type Communication (MTC) is increasing and is expected to play an important role in the future network society. In the process of increasing the number of connected devices, the coverage plays an important role. This thesis work aims to study the possibility of supporting coverage limited MTC-devices within LTE by extending the LTE coverage. It shows that coverage increase by means of repetition is a good candidate, which allows for a significant increase without hardware upgrades at a low cost in terms of radio resources. For inter-site distances up to 2500 m, the proposed repetition scheme with an increase of 20 dB allows for almost complete coverage where today’s LTE have significant lack of coverage. It also shows that even though the increased coverage implies higher resource usage, the limitation is not in the number of users supported, but rather the coverage at longer inter-site distances.

Cell search of Third Generation Partnership Project Long Term Evolution (3GPP LTE) includes time synchronization and frequency synchronization of frames, and the acquisition of Cell Identity (Cell ID). The LTE systems use 504 Cell IDs divided into 168 unique Cell-Identity Groups (Cell-ID Groups), and each Cell-ID Group comprises three Sector Identities (Sector IDs). After reaching synchronization of time and frequency between frames, the Cell ID acquisition scheme provided by specification of 3GPP LTE is consisted of two steps, the first step must utilize three matched filters to detect one out of three Sector IDs, and then implement coherent correlation detection between 168 Pseudo Random Noise Sequences (PN sequences) to obtain the index of Cell-ID Group. So the cell search scheme provided by LTE standard has to detect correlation of all sequences, and computed complexity brings considerable processing time to effect the delay time of services power on, standby time, energy saved, and cost of manufacture. To reduce complexity, we propose a perfect sequence with special structure as preamble, and the sequence is linear combination of two base sequences. We put the sequences within Primary Synchronization Channel (P-SCH) and Secondary Synchronization Channel (S-SCH), and we utilize the phase rotation factors of the sequences as index to generate Cell ID, instead of the current scheme to generate Cell ID with the indexes between sequences and sequences. Based on the sequences in multipath channel model, simulation results verify the detection probability of Cell IDs by proposed scheme is 100% when SNR is -8dB, and it is 98.7% by the scheme in LTE specification after perfect time and frequency compensation. Except that, Cell ID detection performance is similar without channel compensation to reduce implement complexity. Index Terms- cell search, 3GPP LTE, 16n perfect sequence.

Nos travaux s’orientent vers les problèmes de réseaux sans fil liés à la coexistence des communications machine-to-machine (M2M) et humain-humain (H2H). On souhaite souligner l'impact mutuel entre les trafics M2M et H2H dans un contexte d’Internet des objets (IoT : Internet Of Things) en particulier lors des catastrophes. Les communications M2M, qui devraient connaître une roissance exponentielle dans un avenir proche, constitueront un facteur important pour affecter tous les réseaux mobiles. On prévoit un grand nombre d'appareils M2M qui entraînera inévitablement des problèmes de saturation et aura des impacts remarquables sur les trafics, les services et les applications M2M et H2H. Pour étudier les influences mutuelles M2M et H2H, nous développons un nouveau modèle markovien à temps continu (CTMC) pour simuler, analyser et mesurer les différentes stratégies d'accès aux réseaux sans fil. Notre modèle nous a permis de contourner certaines limitations des simulateurs professionnels de LTE-A (Long Term Evolution-Advanced) comme SimuLTE en terme d’un nombre massif d'appareils M2M, une flexibilité de certains paramètres ou pour élaborer plus des outils statistiques. Lors d’un sinistre et suite à un énorme nombre de M2M souhaitant accéder aux réseaux sans-fil, nous avons constaté un épuisement rapide de la bande passante allouée dans les réseaux LTE-M (Long Term Evolution for Machines) ou Narrow Band for IoT (NB-IoT). Pour résoudre ce problème, nous proposons une nouvelle approche appelée Adaptive eNodeB (A-eNB) pour les réseaux LTE-M et NB-IoT. Selon nos simulations, l’A-eNB peut résoudre progressivement le problème de surcharge tout en assurant une satisfaisante qualité de service (QoS) pour le trafic H2H. Avec le concept d’A-eNB, un réseau LTE-M pourra adapter ses ressources pour faire face à une augmentation progressive du nombre de connexions M2M accédant au réseau LTE-M / NB-IoT et en même temps réduire l'impact sur le trafic H2H. / This Ph.D. work aims to study the Machine-to-Machine (M2M) congestion overload problem and the mutual impact among M2M and Human-to-Human (H2H) traffics in IoT (Internet of Things) environments specifically during disaster events. M2M devices with their expected exponential booming in the near future, will be one of the significant factors to influence all mobile networks. Inevitably, the expected huge number of M2M devices causes saturation problems, and leads to remarkable impacts on both M2M and H2H traffics, services and applications. To study the M2M and H2H mutual influences, we create a new platform model based on Continuous-Time Markov Chain (CTMC) to simulate, analyze and measure radio access strategies due to the limitations of existing Long Term Evolution-Advanced (LTE-A) simulators (i.e, SimuLTE) in term of massive M2M devices, parameter flexibility and statistical tools. Additionally, during disaster events, a fast bandwidth depletion of the limited bandwidth assigned to M2M devices in Long Term Evolution for Machines (LTE-M) and Narrow Band for IoT (NB-IoT) networks is expected due to the high arrival request of M2M device network access. To address this problem, we propose a new approach named Adaptive eNodeB (A-eNB) for both LTE-M and NB-IoT networks. The A-eNB can solve gradually the overload problem, while keeping the H2H traffic Quality of Service (QoS) not to be affected badly. The network adaptation is provided through a dynamic LTE-M resource reservation aiming to increase the number of M2M connections accessing the LTE-M/NB-IoT network and to decrease the impact on H2H traffic.

With the introduction of 4G LTE, multiple new technologies were introduced. MIMO is one of the important technologies introduced with fourth generation. The main MIMO modes used in LTE are open loop and closed loop spatial multiplexing modes. This thesis develops an algorithm to calculate the threshold values of UE speed and SNR that is required to implement a switching algorithm which can switch between different MIMO modes for a UE based on the speed and channel conditions (CSI). Specifically, this thesis provides the values of UE speed and SNR at which we can get better results by switching between open loop and closed loop MIMO modes and then be scheduled in sub-channels accordingly. Thus, the results can be used effectively to get better channel capacity with less ISI. The main objectives of this thesis are: to determine the type of MIMO mode suitable for a UE with certain speed, to determine the effects of SNR on selection of MIMO modes, and to design and implement a scheduling algorithm to enhance channel capacity.