Algorithms and protocols for multi-channel wireless networks

A wireless channel is shared by all devices, in the vicinity, that are tuned to the channel, and at any given time, only one of the devices can transmit information. One way to overcome this limitation, in throughput capacity, is to use multiple orthogonal channels for different devices, that want to transmit information at the same time. In this work, we consider the use of multiple orthogonal channels in wireless data networks. We explore algorithms and protocols for such multi-channel wireless networks under two broad categories of network-wide and link-level challenges. Towards handling the network-wide issues, we consider the channel assignment and routing issues in multi-channel wireless networks. We study both single radio and multi-radio multi-channel networks. For single radio multi-channel networks, we propose a new granularity for channel assignment, that we refer to as component level channel assignment. The strategy is relatively simple, and is characterized by several impressive practical advantages. For multi-radio multi-channel networks, we propose a joint routing and channel assignment protocol, known as Lattice Routing. The protocol manages channels of the radios, for the different nodes in the network, using information about current channel conditions, and adapts itself to varying traffic patterns, in order to efficiently use the multiple channels. Through ns2 based simulations, we show how both the protocols outperform other existing protocols for multi-channel networks under different network environments. Towards handling the link-level challenges, we identify the practical challenges in achieving a high data-rate wireless link across two devices using multiple off-the-shelf wireless radios. Given that the IEEE 802.11 a/g standards define 3 orthogonal wi-fi channels in the 2.4GHz band and 12 orthogonal wi-fi channels in the 5GHz band, we answer the following question: ``can a pair of devices each equipped with 15 wi-fi radios use all the available orthogonal channels to achieve a high data-rate link operating at 600Mbps?' Surprisingly, we find through experimental evaluation that the actual observed performance when using all fifteen orthogonal channels between two devices is a mere 91Mbps. We identify the reasons behind the low performance and present Glia, a software only solution that effectively exercises all available radios. We prototype Glia and show using experimental evaluations that Glia helps achieve close to 600Mbps data-rate when using all possible wi-fi channels.PhDCommittee Chair: Sivakumar, Raghupathy; Committee Member: Blough, Doug; Committee Member: Coyle, Edward; Committee Member: Eidenbenz, Stephan; Committee Member: Fekri, Faramar

Sistema de gestión de dispositivos IoT enfocados en escenarios de smart cities

En este documento se presenta el desarrollo de una aplicación para la gestión y monitorización remota de nodos con capacidad para integrarse en escenarios diseñados para Smart Cities. En concreto, la aplicación permite monitorear variables tales como la carga de la CPU, el uso de la memoria, la temperatura del dispositivo y el consumo de energía. En cuanto al dispositivo a gestionar, este consiste en una plataforma Raspberry Pi 4 con el sistema operativo Raspberry Pi OS 1.4, sobre la cual se instalaron sensores para la adquisición de datos de geolocalización y variables ambientales como contaminación, temperatura y luz, así como el uso de una batería para energizar el nodo. En la tarea de gestión de los nodos se empleó el protocolo SNMPv3 (Simple Network Management Protocol), de esta manera el usuario tiene la posibilidad de optimizar los recursos del sistema (sensores y consumo energético). La aplicación se desarrolló utilizando el framework Node-RED, en un ordenador con el sistema operativo Ubuntu 20.04. Esta aplicación cuenta con una interfaz de usuario y la capacidad de conectarse a la nube de IBM para su monitoreo desde Internet. La conexión entre los nodos se realizó mediante una red Ad Hoc multi-salto. Adicionalmente, en el ordenador se configuró un gateway por defecto que permite la conexión de los nodos Ad Hoc hacia Internet. Con la finalidad de emular una red tipo Ad Hoc multi-salto con cuatro nodos, se utilizó la herramienta NS3, la misma que permite adecuar el escenario a uno real al realizar las simulaciones utilizando hardware sobre contenedores Linux. De esta forma fue posible inyectar tráfico SNMP real en la red simulada. Para la evaluación de la red se empleó un escenario multi-salto conformado por cuatro nodos fijos. Se realizaron experimentos empleando enrutamiento estático y dinámico mediante OLSR (Optimized Link Route State). Y finalmente se planteó un experimento adicional considerando un quinto nodo con capacidad de desplazamiento. En la red emulada se realizó el análisis de métricas de red como: el tráfico, el porcentaje de recepción de paquetes, el retardo de la red y por último se midió la capacidad de ancho de banda.In this document the development of an application for the remote management and monitoring, is presented, with capabilities to integrate into scenarios designed for Smart Cities. Specifically, the application enables monitoring variables as: CPU load, memory usage, device temperature and power consumption. On a Raspberry Pi 4 with Raspberry Pi OS 1.4 as operating system, the installation of environmental and geolocation sensors as: pollution, temperature and light, furthermore, the use of a battery to power the node. In the node management task, the SNMPv3 (Simple Network Management Protocol) is implemented for resource management of the node. Thus, the user has the possibility to optimize system resources (sensors and power consumption). The application is developed in the framework Node-RED in a computer with the operating system Ubuntu 20.04. This application has a user interface and the capacity to connect to the IBM cloud for monitoring from the internet. The connection between the nodes is made through an Ad Hoc network, in the computer a default gateway is configured that allows the network connection to the internet from the Raspberry Pi. In order to emulate a multi-hop Ad Hoc network with four nodes, the NS3 tool is used, which allows to adapt the scenario to a real one by performing simulations using hardware on Linux containers, through real SNMP traffic is injected into the network in static and mobile scenarios, using static routing and the OLSR (Optimized Link Route State) protocol. Finally, an additional experiment was proposed considering a fifth node with displacement capacity. In the emulated network, the analysis of network metrics such as: throughput, percentage of packet reception, delay and the network bandwidth capacity are measured.Ingeniero en Electrónica y TelecomunicacionesCuenc