Análisis del modelo de sombreado normal-logarítmico aplicado a un enlace LoRa punto a punto

LoRa is a low-power wireless technology and long range used in wide area network. In addition to LoRa, there are other wireless technologies for data transmission with several qualities. However, LoRa technology can be exploited in different applications such as Wireless Sensor Network (WSN), tracking and location. This is due to its great advantage to support a high number of communication devices. The LoRa technology is based on the Chirp Spread Spectrum (CSS) modulation, this provides robustness to noise and other phenomena of degradation channel. In this work, it is presented the LoRa Technology performance in indoor and quasi-indoor environments with a point-to-point connection to estimate the distance based on the Received Signal Strength Indication (RSSI). The RSSI measurements, the estimating logarithmic function to compute distances and errors are shown in this manuscript. Finally, it can be concluded that the results are satisfactory, with an acceptable margin of error for indoor and quasi-indoor environments.LoRa es una tecnología inalámbrica de bajo consumo de potencia y largo alcance empleada en redes de área amplia. Además de LoRa, en el mercado existen otras tecnologías inalámbricas para transmisión de datos con diversas cualidades. Sin embargo, la tecnología LoRa se puede explotar en diferentes aplicaciones tales como redes de sensores inalámbricas (WSN, por sus siglas en inglés), rastreo y localización. Esto debido a su gran ventaja de soportar un gran número de dispositivos de comunicación. La tecnología LoRa está basada en la técnica de modulación Chirp Spread Spectrum (CSS, por sus siglas en inglés), esto le proporciona robustez ante el ruido y otros fenómenos de degradación de canal. En el presente trabajo se presenta el desempeño de la tecnología LoRa en ambientes interiores y semi-interiores con una conexión punto a punto para estimar la distancia basado en el indicador de la intensidad de la señal recibida (RSSI, por sus siglas en inglés). Las mediciones de RSSI realizadas, la estimación de las funciones logarítmicas para calcular las distancias y los errores, son presentados en este documento. Finalmente, se puede concluir que los resultados obtenidos son satisfactorios, con un margen de error aceptable para ambientes interiores y semi-interiores

Localized Application for Video Capture for a Multimedia Sensor Node with Name-Based Segment Streaming

abstract: The Internet of Things (IoT) has become a more pervasive part of everyday life. IoT networks such as wireless sensor networks, depend greatly on the limiting unnecessary power consumption. As such, providing low-power, adaptable software can greatly improve network design. For streaming live video content, Wireless Video Sensor Network Platform compatible Dynamic Adaptive Streaming over HTTP (WVSNP-DASH) aims to revolutionize wireless segmented video streaming by providing a low-power, adaptable framework to compete with modern DASH players such as Moving Picture Experts Group (MPEG-DASH) and Apple’s Hypertext Transfer Protocol (HTTP) Live Streaming (HLS). Each segment is independently playable, and does not depend on a manifest file, resulting in greatly improved power performance. My work was to show that WVSNP-DASH is capable of further power savings at the level of the wireless sensor node itself if a native capture program is implemented at the camera sensor node. I created a native capture program in the C language that fulfills the name-based segmentation requirements of WVSNP-DASH. I present this program with intent to measure its power consumption on a hardware test-bed in future. To my knowledge, this is the first program to generate WVSNP-DASH playable video segments. The results show that our program could be utilized by WVSNP-DASH, but there are issues with the efficiency, so provided are an additional outline for further improvements.Dissertation/ThesisMasters Thesis Computer Engineering 201

A Novel Approach to Transmission Power, Lifetime and Connectivity Optimization in Asymmetric Networks

This thesis deals with the problem of proper power management over asymmetric networks represented by weighted directed graphs (digraphs) in the presence of various constraints. Three different problems are investigated in this study. First, the problem of total transmission power optimization and connectivity control over the network is examined. The notion of generalized algebraic connectivity (GAC), used as a network connectivity measure, is formulated as an implicit function of the nodes' transmission powers. An optimization problem is then presented to minimize the total transmission power of the network while considering constraints on the values of the GAC and the individual transmission power levels. The problem of network lifetime maximization and connectivity control is investigated afterwards. Each node is assumed to deplete its battery linearly with respect to the transmission powers used for communication, and the network lifetime is defined as the minimum lifetime over all nodes. Finally, it is desired to maximize the connectivity level of the network with constraints on the total transmission power of the network and the individual transmission powers. The interior point and the mixed interior point-exterior point methods are utilized to transform these constrained optimization problems into sequential optimization problems. Given the new formulation, each subproblem is then solved numerically via the subgradient method with backtracking line search. A distributed version of the algorithm, taking into account the estimation of global quantities, is provided. The asymptotic convergence of the proposed centralized and distributed algorithms is demonstrated analytically, and their effectiveness is verified by simulations

The Impact of Transmission Power Control Strategies on Lifetime of Wireless Sensor Networks

Transmission power control has paramount importance in the design of energy-efficient wireless sensor networks (WSNs). In this paper, we systematically explore the effects of various transmission power control strategies on WSN lifetime with an emphasis on discretization of power levels and strategies for transmission power assignment. We investigate the effects of the granularity of power levels on energy dissipation characteristics through a linear programming framework by modifying a well known and heavily utilized continuous transmission power model (HCB model). We also investigate various transmission power assignment strategies by using two sets of experimental data on Mica motes. A novel family of mathematical programming models are developed to analyze the performance of these strategies. Bandwidth requirements of the proposed transmission power assignment strategies are also investigated. Numerical analysis of our models are performed to characterize the effects of various design parameters and to compare the relative performance of transmission power assignment strategies. Our results show that the granularity of discrete energy consumption has a profound impact on WSN lifetime, furthermore, more fine-grained control of transmission power (i.e., link level control) can extend network lifetime up to 20% in comparison to optimally-assigned network-level single transmission power