Analisi di protocolli HARQ per il sistema cellulare LTE. Analysis of HARQ protocols for LTE cellular system

In questa tesi vengono studiati i protocolli di Hybrid-ARQ (HARQ) implementati in LTE. Vengono ricavati modelli analitici dei suddetti protocolli e viene proposta una modifica che, tramite un approccio Bayesiano, ne migliora le prestazioni in termini di throughput e di ritardo. La quantificazione dei miglioramenti viene effettuata valutando i modelli proposti per via numerica. Il lavoro è stato ispirato dai requisiti delle reti cellulari 5G che sono in fase di definizioneopenEmbargo temporaneo per motivi di segretezza e/o di proprietà dei risultati e/o informazioni sensibil

Long-Range Communications in Unlicensed Bands: the Rising Stars in the IoT and Smart City Scenarios

Connectivity is probably the most basic building block of the Internet of Things (IoT) paradigm. Up to know, the two main approaches to provide data access to the \emph{things} have been based either on multi-hop mesh networks using short-range communication technologies in the unlicensed spectrum, or on long-range, legacy cellular technologies, mainly 2G/GSM, operating in the corresponding licensed frequency bands. Recently, these reference models have been challenged by a new type of wireless connectivity, characterized by low-rate, long-range transmission technologies in the unlicensed sub-GHz frequency bands, used to realize access networks with star topology which are referred to a \emph{Low-Power Wide Area Networks} (LPWANs). In this paper, we introduce this new approach to provide connectivity in the IoT scenario, discussing its advantages over the established paradigms in terms of efficiency, effectiveness, and architectural design, in particular for the typical Smart Cities applications

Location-Verification and Network Planning via Machine Learning Approaches

In-region location verification (IRLV) in wireless networks is the problem of deciding if user equipment (UE) is transmitting from inside or outside a specific physical region (e.g., a safe room). The decision process exploits the features of the channel between the UE and a set of network access points (APs). We propose a solution based on machine learning (ML) implemented by a neural network (NN) trained with the channel features (in particular, noisy attenuation values) collected by the APs for various positions both inside and outside the specific region. The output is a decision on the UE position (inside or outside the region). By seeing IRLV as an hypothesis testing problem, we address the optimal positioning of the APs for minimizing either the area under the curve (AUC) of the receiver operating characteristic (ROC) or the cross entropy (CE) between the NN output and ground truth (available during the training). In order to solve the minimization problem we propose a twostage particle swarm optimization (PSO) algorithm. We show that for a long training and a NN with enough neurons the proposed solution achieves the performance of the Neyman-Pearson (N-P) lemma.Comment: Accepted for Workshop on Machine Learning for Communications, June 07 2019, Avignon, Franc

On the Support of Massive Machine-to-Machine Traffic in Heterogeneous Networks and Fifth-Generation Cellular Networks

The widespread availability of many emerging services enabled by the Internet of Things (IoT) paradigm passes through the capability to provide long-range connectivity to a massive number of things, overcoming the well-known issues of ad-hoc, short-range networks. This scenario entails a lot of challenges, ranging from the concerns about the radio access network efficiency to the threats about the security of IoT networks. In this thesis, we will focus on wireless communication standards for long-range IoT as well as on fundamental research outcomes about IoT networks. After investigating how Machine-Type Communication (MTC) is supported nowadays, we will provide innovative solutions that i) satisfy the requirements in terms of scalability and latency, ii) employ a combination of licensed and license-free frequency bands, and iii) assure energy-efficiency and security

Risk factors for motherhood among adolescents living with HIV

O presente estudo buscou identificar os fatores de risco para a vivência da gestação e maternidade em jovens vivendo com HIV. Realizou-se um estudo qualitativo de casos múltiplos com três jovens HIV+ (17 a 19 anos), primíparas, com bebês de 4 a 6 meses, recrutadas em serviços especializados de Porto Alegre, Brasil. Os dados foram coletados por meio de entrevista semi-estruturada e questionários de apoio social e adesão ao tratamento. Identificaram-se como fatores de risco para maiores dificuldades na vivência da gestação/maternidade: descoberta da soropositividade durante a gestação, baixa adesão ao tratamento antirretroviral e não realização desse tratamento pelo parceiro, além de dificuldades enfrentadas nos serviços de saúde. Os achados indicam a necessidade de busca ativa de adolescentes gestantes/mães que vivem com HIV e de inclusão do companheiro no seu acompanhamento de saúde, a fim de minimizar o impacto desses fatores de risco e facilitar a transição para a maternidade

Analysing the experience of motherhood among adolescents living with HIV

AimAdolescent motherhood is considered a condition of vulnerability that can be further complicated by the presence of HIV infection, but little is known about how adolescent mothers experience this process. The aim of this study was to analyse the experience of motherhood among adolescents living with HIV.MethodSeven mothers (15-21 years) recruited in specialized services in Porto Alegre/Brazil, whose babies’ ages ranged from four to six months, were interviewed. Interviews were tape-recorded and transcribed verbatim.ResultsThe qualitative content analysis of the interviews revealed a positive vision of motherhood, related to satisfaction with the maternal role and personal fulfilment. Pregnancy and motherhood served to these adolescents as an encouragement for self-care. The mothers’ difficulties were related to HIV and to the repercussions of this clinical condition, especially feelings of frustration and incompleteness of motherhood on the impossibility of breastfeeding, as well as fear facing the risk of MTCT.ConclusionFuture research of longitudinal design and with larger samples will be important to extend the knowledge of the specificities of this experience over time for young people of different ages and social backgrounds

Impacto do estilo de vida na adaptação individual e relacional e nos resultados obstétricos de mulheres adultas após o parto

This study aimed to examine and retrospectively compare the lifestyles of adult women before and during pregnancy; to describe individual and relational adaptation in the transition to motherhood and obstetric outcomes; and to examine the associations between lifestyle habits and these outcomes. The sample comprised 98 mothers, most of them married or cohabiting, nulliparous, with completed secondary or higher education. Most of them had planned their pregnancy. A questionnaire on sociodemographic information, the Emotional Assessment Scale, the Brief Symptom Inventory, and adjectival scales to assess marital and parental domains were employed. Results indicated a positive change in lifestyle adopted during pregnancy compared to the preceding period. The adoption of healthy lifestyle habits was significantly associated with lower psychological distress and positive emotional reactivity. These findings highlight the importance of assessing different components of lifestyle and their association with diverse individual and relational indicators to gain a broader understanding of women’s adaptation in the transition to motherhood.O objetivo deste estudo foi analisar e comparar retrospetivamente o estilo de vida (EV) de mulheres antes e durante a gravidez; descrever a adaptação individual e relacional na transição para a maternidade e os resultados obstétricos; e avaliar a associação entre hábitos de EV e estes indicadores. A amostra foi composta por 98 mães, a maioria casadas ou em união de facto, com ensino secundário ou superior, nulíparas e que planearam a gravidez. A bateria de avaliação incluiu um questionário sociodemográfico, a Escala de Avaliação das Emoções, o Inventário de Sintomas Psicopatológicos e escalas de adjetivos para avaliar os domínios conjugal e parental. Os resultados mostraram uma mudança positiva no EV durante a gravidez em comparação ao período precedente. Foi encontrada uma associação significativa entre a adoção de hábitos de vida saudáveis e menor sintomatologia psicopatológica e maior reatividade emocional positiva. Estes resultados salientam a importância da avaliação de diferentes componentes do EV e a sua associação com diversos indicadores individuais e relacionais para uma melhor compreensão da adaptação das mulheres na transição para a maternidade

Location-Privacy Leakage and Integrated Solutions for 5G Cellular Networks and Beyond

The fifth generation (5G) of cellular networks improves the precision of user localization and provides the means to disclose location information to over-the-top (OTT) service providers. The network data analytics function (NWDAF) can further elaborate this information at an aggregated level using artificial intelligence techniques. These powerful features may lead to the improper use of user location information by mobile network operators (MNOs) and OTT service providers. Moreover, vulnerabilities at various layers may also leak user location information to eavesdroppers. Hence, the privacy of users is likely at risk, as location is part of their sensitive data. In this paper, we first go through the evolution of localization in cellular networks and investigate their effects on location privacy. Then, we propose a location-privacy-preserving integrated solution comprising virtual private mobile networks, an independent authentication and billing authority, and functions to protect wireless signals against location information leakage. Moreover, we advocate the continuous and detailed control of localization services by the user

Experiência da gravidez em situação de seropositividade para VIH: Revisão da literatura Brasileira

Gerar um filho no contexto da seropositividade para VIH/Sida pode ser uma experiência emocionalmente difícil para as mulheres. No presente estudo, realizou-se uma revisão da literatura brasileira da última década (2000-2010) sobre a temática da experiência da gravidez em situação de seropositividade para VIH no Brasil, tendo-se identificado 20 estudos. Mais especificamente, objetivou-se identificar aspectos relevantes para futuras investigações e intervenções psicológicas junto a essa clientela. Os resultados apontaram para experiências típicas do período gestacional, como contato afetivo com o bebê e preocupação com a sua saúde, assim como experiências particulares impostas pela seropositividade, como frustração diante da expectativa da não-amamentação e medo da transmissão vertical. O apoio social destacou-se como aspecto facilitador da adesão ao tratamento e do manejo da infecção. Os resultados encontrados permitem identificar aspectos relevantes para investigações futuras no Brasil e fornecem pistas para a intervenção psicológica junto à população seropositiva