Rodrigues, A. B. Alocação de recursos de rádio para sistemas sc-fdma baseado em relaxamento e programação linear. 2016. 73 f. Dissertação (Mestrado em Engenharia Elétrica e da Computação) - Campus de Sobral, Universidade Federal do Ceará, Sobral, 2016. / Submitted by Programa de Pós-Graduação Engenharia Elétrica e de Computação (secretaria_ppgeec@sobral.ufc.br) on 2017-03-06T21:14:14Z No. of bitstreams: 1 2016_dis_abrodrigues.pdf: 1200876 bytes, checksum: 65bf4b1452b81c2dd6e5c26b0ab5bbc4 (MD5) / Approved for entry into archive by Ana Márcia Sousa (marciasousa@ufc.br) on 2017-03-07T11:23:43Z (GMT) No. of bitstreams: 1 2016_dis_abrodrigues.pdf: 1200876 bytes, checksum: 65bf4b1452b81c2dd6e5c26b0ab5bbc4 (MD5) / Made available in DSpace on 2017-03-07T11:23:43Z (GMT). No. of bitstreams: 1 2016_dis_abrodrigues.pdf: 1200876 bytes, checksum: 65bf4b1452b81c2dd6e5c26b0ab5bbc4 (MD5) Previous issue date: 2017-03 / In this work, we study the maximization problem of the sum of the weighted data rates in the wireless system’s uplink that uses SC-FDMA. The SC-FDMA multiple access scheme was adopted in the LTE uplink especially because it eases the power amplifier design in the mobile terminals. However, SC-FDMA presents an important restriction in radio resource allocation that is not present in OFDMA that was adopted in the LTE downlink: the resource adjacency or contiguity. With the resource adjacency constraint, the blocks of frequency resources assigned to each mobile terminal should be adjacent in the frequency domain. From the resource allocation point of view, this new constraint not only makes ineffective all previous resource allocation solutions proposed for OFDMA but also turns the problems even more harder in terms of computational complexity. In this work, we study the total data rate maximization problem in uplink SC-FDMA systems. Firstly, we discuss about the optimal solution of the problem that can be obtained through the use of integer optimization techniques. Motivated by the high computational complexity of this solution, we propose an alternative solution based on integer optimization relaxation and application of linear programming. The simulation results show that our proposed scheme is able to achieve the optimal solution in 55% (at least) of the simulations with a much lower computational complexity. For the cases where the solution obtained by continuous linear programming is not integer, the study proposes an algorithm that obtains an integer solution through rounding techniques. We also present a performance analysis comparing the algorithm developed with algorithms present in the literature. / Neste trabalho, estudamos o problema de maximização do somatório das taxas de dados ponderadas no enlace reverso de um sistema sem fio que emprega Single Carrier - Frequency Division Multiple Access (SC-FDMA). O esquema de múltiplo acesso SC-FDMA apresenta uma importante restrição quanto a alocação de recursos que não está presente em sistemas Orthogonal Frequency Division Multiple Access (OFDMA) (esquema utilizado no enlace direto de sistemas Long Term Evolution (LTE)): a contiguidade ou adjacência de blocos de recursos na frequência. A restrição de adjacência implica que a alocação dos blocos de recursos a cada terminal móvel deve ser feita de forma contígua na frequência. Na ótica de alocação de recursos em redes móveis, essa nova restrição não só inviabiliza o uso das soluções desenvolvidas para OFDMA encontradas na literatura, mas também torna o problema bem mais desafiador do ponto de vista matemático e computacional. Primeiramente, nós discutimos sobre a solução ótima desse problema que pode ser obtida através de programação inteira. Motivado pela alta complexidade computacional desta solução, propomos o uso de técnicas de relaxamento do problema de otimização inteiro e aplicação de programação linear (contínua). Através de simulações computacionais, demonstramos que o esquema proposto é capaz de encontrar a solução ótima em pelo menos 55% das simulações realizadas com uma complexidade computacional muito menor. Para os casos em que a solução obtida pela programação linear contínua não é inteira, o estudo propõe um algoritmo que obtém uma solução inteira através de técnicas de arredondamento. Apresentamos também uma análise de desempenho comparando o algoritmo desenvolvido com algoritmos presentes na literatura.

The number of wireless connected devices are growing exponentially and the importance of this research area is growing as well to meet the known and looming challenges and expectations. The 5:th Generation telecommunications standard is partly embodied by the Machine-to-Machine (M2M) and Internet of Things (IoT) technologies and standards to handle a big part of these devices and connections. An example within the IoT paradigm is military training systems where each system can consist of thousands of battery operated mobile devices and their shifting requirements shall be fullled in an energy-aware manner to increase battery operating times. Military training radio networks enables realistic combat training. The services and features provided in commercial telecommunications networks are desirable in these often proprietary and task specic networks, increasing capabilities and functionalities. To facilitate the current and future R&D of LTE based networks for adoption in military training networks and services this doctoral thesis intends to provide the starting ground for the energy-aware LTE based wireless communications. The thesis first presents general solutions on how to meet traffic deadlines in wireless networks for large number of nodes, and then continues with solutions for energy-aware LTE-based communications for the User Equipments (UEs). The work builds on the problem formulation how to provide energy-aware resource handling for LTE-based military training networks from where three research questions are derived. From the research questions we derive different hypotheses and then test these within the investigated area to answer the research questions. The contributions of this work are within areas of resource handling and power saving for mobile devices. In the first area an admission control using deterministic analysis is proposed fullling traffic requirements for military training mobile nodes. This admission control is enhanced for multiple-channel base stations, and evaluated using mobile nodes with different heterogeneous traffic requirements. In the second part energy-awareness is in focus for LTE/LTE-A based networks. The main power saving method for LTE/LTE-A UEs, Discontinuous Reception (DRX) mechanism, is evaluated and models for DRX in Idle and Connected state are proposed including metrics for wake-up delay and power saving. Additionally a mean queuing delay analysis is proposed for a variant of the Connected state DRX. Using these models and metrics, practical design guidelines for tuning of DRX parameters are proposed, including optimization of DRX parameters for either minimizing delay or maximizing power saving.

The significant growth in multimedia services and traffic (e.g. VoIP, video streaming and video gaming) in current and emerging mobile networks including the latest 4G Long-Term Evolution (LTE) networks and the rising user expectation for high Quality of Experience (QoE) for these services have posed real challenges to network operators and service providers. One of the key challenges is how to bring multimedia services to the end-user over resource-constrained mobile networks with a satisfactory QoE. Cost-effective solutions are needed for network operators to improve the bandwidth usage of these mobile networks. Therefore, scheduling schemes are of extreme importance in LTE, where scheduling algorithms are responsible for the overall efficiency of resource allocation in an LTE system. The aim of the project is to develop novel QoE-driven scheduling algorithms for improving system capacity in delivering multimedia services over downlink 3GPP LTE. This is to move away from traditional QoS-driven scheduling schemes to a QoE-driven scheme which guarantee end-user satisfaction in resource allocation. The main contributions of the thesis are threefold: 1. Performance of several existing scheduling algorithms for VoIP applications was evaluated thoroughly in terms of QoE metric (i.e. MOS), instead of QoS metrics (e.g. packet loss and delay). Using QoE metrics instead of QoS ones will facilitate the development of QoE-driven scheduling schemes in order to achieve optimised end-user experiences or optimised mobile system capacity. 2. A novel QoE-driven LTE downlink scheduling scheme for VoIP application was developed to maximize the number of users per cell at an acceptable MOS score. The proposed scheme achieved significant improvement in cell capacity at an acceptable quality (75% compared to MLWDF, and 250% compared to PF and EXP-PF in all three lower speed scenarios considered). 3. A QoE-driven LTE downlink scheduling scheme for multiservice multimedia applications was developed to improve the cell capacity with satisfactory QoE for both VoIP and video streaming services. The proposed algorithm performed well in a pedestrian scenario increasing cell capacity to double for video stream with ‘Rapid Movement’ (RM) content. For ‘Medium Movement’ (MM) video content, the capacity was increased about 20% compared to MLWDF and by 40% compared to EXP-PF. In a vehicular scenario, the proposed scheme managed to enhance the cell capacity for MM video stream case. The project has led to three publications (IEEE Globecom’12 – QoEMC Workshop, IEEE CCNC’15 and IEEE MMTC E-letter/May-2015). A journal paper is in preparation.

Les réseaux actuels et la prochaine génération des réseaux sans fil cellulaires (5G) doivent garantir, non seulement, les communications entre les gens (aussi connu sous le nom d'humain à humain - H2H), mais aussi à un déploiement massif de communication de type machine (MTC). MTC, ou encore Machine à Machine (M2M), peut être considérée comme des appareils qui peuvent établir des communications avec d’autres appareils sans aucune intervention humaine. M2M est aussi vue comme la pierre angulaire de la vision des objets connectés (IoT). Elle attire beaucoup d'attention, car elle peut être considérée comme une nouvelle opportunité pour les opérateurs de réseau et service IoT. Il existe aujourd’hui plusieurs types d’applications se basant sur MTC couvrant plusieurs domaines. On peut citer comme exemples les applications suivantes: la santé, les systèmes de transport intelligents (ITS), les compteurs intelligents et les réseaux intelligents, et la sécurité publique (PS). Le déploiement de ce type d'applications dans les réseaux mobiles cellulaires actuels, particulièrement Long Term Evolution (LTE) et LTE-Advanced (LTE-A) , ne peut être effectif sans surmonter les challenges posés par le déploiement d’un grand nombre d’équipement MTC dans la même cellule. En effet, le déploiement d'une myriade d'appareils MTC causera une congestion et une surcharge du système des réseaux d'accès radio (RAN) et du cœur de réseau (CN). Comme les appareils MTC sont équipés d'une batterie non rechargeable, la consommation d'énergie est aussi un défi. Dans cette thèse, nous allons étudier les problèmes de congestion et de consommation d'énergie dans le contexte des réseaux LTE et LTE-A en présence des appareils M2M. En ce qui concerne la congestion et la surcharge de système, nous nous concentrons sur la partie RAN, puisqu'elle peut être considérée comme la première ligne de défense pour le réseau cellulaire. Les contributions de cette thèse sont organisées sous les axes suivants: 1) Proposition d'un algorithme générique pour prédire le trafic entrant, de sorte que la congestion dans le réseau peut être facilement résolue, 2) Étude et proposition d'un modèle analytique générique de la procédure d'accès aléatoire au canal (RACH). Le modèle a pour but l’évaluation des méthodes de contrôle de congestion ciblant la partie RAN, 3) Approfondissement et proposition des méthodes permettant d'améliorer la méthode Pagination de Groupe (GP) approuvée par le 3GPP pour contrôler la congestion. / The current and next generation wireless cellular networks (5G) have to deal with not only communications between people (known as Human-to-Human - H2H), but also with a massive deployment of Machine-Type-Communication (MTC). MTC, or alternatively Machine-to-Machine (M2M), can be viewed as devices connected among them without any human intervention. M2M can be considered as the cornerstone of Internet-of-Things (IoT) vision. It attracts a lot of attention, since it can be considered as a new opportunity and business market. Nowadays, there is a vast number of MTC applications, covering a large number of fields. Some of these applications are Healthcare, Intelligent Transport System (ITS), smart metering and smart grids, public safety (PS), forming the so-called smart city. Deploying this type of applications in the current cellular mobile networks, especially Long Term Evolution (LTE) and LTE-Advanced (LTE-A), cannot be achieved before overcoming the accompanied challenges. Indeed, caused by the existence of a myriad of MTC devices, Radio Access Network (RAN) and Core Network (CN) congestion and system overload is one of these challenging issues. As the MTC devices are using non-rechargeable batteries, power consumption is also a challenge. In this thesis, we study the congestion and power consumption problems in the context of LTE and LTE-A networks featuring M2M communications. Regarding the congestion and system overload, the focus will be on the RAN part since it can be considered as the first defense line on the network. The contributions of the thesis are organized on the following axes: 1) Propose a general algorithm to predict the incoming traffic, so that the congestion in the network can be easily remedied, 2) Study and propose a general analytical model of the Random Access Channel (RACH) procedure. The model can help to evaluate the congestion control methods targeting the RAN part, 3) Depth study and propose methods improving the performance of Group Paging (GP) method, one of the methods approved by 3GPP to control the congestion.

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The aim is to define the market data services, with an emphasis on newly developed LTE network. Furthermore, to analyze the current state of Telefónica Czech Republic a.s. and its surroundings. Define the main LTE development strategy in the approach to the development of the network in different variants and evaluate which of these strategies is the preferred one. The selected strategy is then confronted with the benefits that the development of LTE networks will bring and in the end the decision to develop the network in the future is evaluated.

Consumer drones have used both standards such as Wi-Fi as well as proprietary communication protocols, such as DJI's OcuSync. While these methods are well suited to certain flying scenarios, they are limited in range to around 4.3 miles. Government and military unmanned aerial vehicles (UAVs) controlled through satellites allow for a global reach in a low-latency environment. To address the range issue of commercial UAVs, this thesis investigates using standardized cellular technologies for command and control of UAV systems. The thesis is divided into five chapters: Chapter 1 is the introduction to the thesis. Chapter 2 describes the equipment used as well as the test setup. This includes the drone used, the cellular module used, the microcontroller used, and a description of the software written to collect the data. Chapter 3 describes the data collection goals, as well as locations in the sky that were flown in order to gather experimental data. Finally, the results are presented in Chapter 4, which draws limited correlation between the collected data and flight readiness Chapter 5 wraps up the thesis with a conclusion and future areas for research are also presented.

The latest advancements in mobile device technology are putting ever-higher demands for throughput of wireless networks. This is threatening to outpace the ability of service providers to deploy the necessary infrastructure. Fifth-Generation Mobile Network (5G) technology is experiencing rapid adoption as part of the effort to meet demand, and along with it researchers are continuously seeking new metrics and models for use in predicting the limits of current and future network infrastructure. To succeed, it is key that they have access to methods for simple, effective analysis of the wireless propagation channel in any given location. The typical laboratory test environment lacks the unpredictability and uniqueness of real-world conditions. Additionally, it utilizes equipment whose specifications are often far removed from devices that are actually intended to operate on the mobile network, such as smartphones themselves. This work focuses on the nature of contemporary path loss models and their ability to accurately predict signal levels, seeking to validate their use against observed path loss behavior in outdoor line-of-sight (LOS) scenarios, where the number of active devices can vary significantly over short periods of time. These conditions are typical of public spaces such as parks and city streets where a large number of users may all simultaneously be accessing high-throughput services. To test their validity, statistics are provided for sets of data collected on foot in public spaces using a novel software utility developed expressly for this purpose. The models we use for comparing against our measured results include both experiential models that are built on other data sets, along with stastically-based, large-scale path loss models. These are compared as a function of distance from the base station (BS), and any unique characteristics of the local network are considered. Finally, a combination of environmental imagery, coverage maps with signal strength overlays, and the aforementioned model comparison are used to estimate the signal source and predict performance in nearby areas.

Det här arbetet har undersökt hur mycket end-to-end delay, packet reception ratio och throughput påverkas av antal bilar, bilars hastighet samt avståndet mellan bilar i en simulerad miljö när standarden IEEE 802.11p och LTE-V2X används för kommunikation. Båda teknologierna använder det licensierade Intelligent Transport System-bandet på 5,9 GHz. För att simulera IEEE 802.11p användes ramverket Veins som kombinerar nätverkssimulatorn OMNeT++ med trafiksimulatorn SUMO, och för LTE-V2X användes SimuLTE. Alla bilar skickade säkerhetsmeddelanden på 320 byte var 100 millisekund. I stadsområdet, korsningen och den raka vägen som studerades presterade IEEE 802.11p bättre än LTE-V2X. Kommunikation med LTE-V2X visade sig vara mycket känsligare för förändringar än när IEEE 802.11p används. När antalet bilar blev fler ändrades delayen betydligt mer för LTE-V2X än IEEE 802.11p. Delayen var nära 0,12 millisekunder i alla tester när IEEE 802.11p användes, medan LTE-V2X varierade från 14 millisekunder till 10 sekunder. Antalet mottagna paket var också mycket högre för IEEE 802.11p än LTE-V2X. Medan packet reception ratio var nära 100% i alla test då IEEE 802.11p användes var LTE-V2X under 50% i de flesta fall. / This study has evaluated the impact on the end-to-end delay, packet reception ratio and throughput of vehicle density, vehicles speed and the distance between vehicles in a simulated environment, where the vehicles were communicating with the standards IEEE 802.11p and LTEV2X. Both technologies operate in the licensed Intelligent Transport System band of 5.9 GHz. The network simulator OMNeT++ was combined with the traffic simulator SUMO to build the V2X simulator. The framework Veins was used to simulate IEEE 802.11p and SimuLTE was used to simulate LTE-V2X. All vehicles sent out safety messages of 320 byte at a rate of 10 Hz, i.e., every 100 milliseconds. In the urban area, intersection and straight road that were studied, IEEE 802.11p performed better than LTE-V2X. It was shown that LTE-V2X is far more sensitive to changes than IEEE 802.11p. When the density got higher the end-to-end delay was changed significantly more for LTE-V2X than IEEE 802.11p. End-to-end delay was near 0.12 milliseconds in all tests when IEEE 802.11p was used, while LTE-V2X ranged from 14 milliseconds to 10 seconds. Packet reception ratio was much higher for IEEE 802.11p than LTE-V2X. While it was near 100% when IEEE 802.11p was used in all tests, LTE-V2X showed a packet reception ratio less than 50% in most cases.

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