Thesis: Software-Defined Radio Techniques for Resource Optimization in Cognitive Wireless Sensor Networks
Posted on by Ramiro Utrilla

Author: Ramiro Utrilla Gutiérrez

Advisor: Alvaro Araujo Pinto

Synopsis: Due to the spectrum scarcity problem, mostly in license-free ISM bands, and the forecasts regarding the increasing adoption of wireless communications, especially in scenarios like cities, it is essential to optimize the use of the spectrum to ensure the proper functioning of services and devices in the near future.

As the characteristics of the spectrum, by their own physical nature and its use, are very dynamic and vary constantly, devices must be able to intelligently adapt to these changes, as the Cognitive Radio paradigm proposes. Moreover, this adaptation should be done quickly in order to be effective and it should minimize the impact on the use of the spectrum.

Because of that, this work is going to be mainly focused on the development and evaluation of cognitive strategies with zero or minimum communication overhead. In other words, the aim of the research is to evaluate the degree of optimization of resources that can be achieved in a Cognitive Wireless Sensor Network (CWSN) by doing the cognitive cycle (spectrum sensing, learning and adaptation) mostly at node-level. To better exploit the cognitive radio capabilities of these networks, and thanks to the current development of wireless and processing technology, Software-Defined Radio (SDR) techniques are going to be used in sensor nodes for that purpose. This approach supposes a new paradigm in CWSNs which implies new challenges to be faced.

At this point, it appears to be necessary to evaluate some issues about the future of wireless communications. Will someday the need for cognition to use the spectrum outweigh the current energy constraints? In other words, will it be possible to achieve efficient and reliable wireless communication without cognitive capabilities in the near future? Answering this question will reveal whether it still make sense to compare the power consumption of SDR solutions with other platforms based on COTS radio transceivers or, conversely, the addition of cognitive capabilities will cease to pose a challenge to maximize systems’ efficiency and become a key point for their proper operation.

 

ContikiHUB
Posted on by b105

Las Redes de Sensores Inalámbricas (WSN por su nombre en inglés, Wireless Sensor Networks) se encuentran en una fase de rápida expansión por su gran valor en aplicacionescomo la domótica, seguridad o la gestión de recursos en el ámbito industrial. Continuando con la línea de investigación en sistemas operativos (OS) para redes de este tipo recientemente iniciada en el laboratorio, hemos decidido realizar un proyecto que resultará de enorme utilidad a la hora de iniciar el despliegue de una WSN.

ContikiHUB es una plataforma que actúa como pasarela entre los nodos de una WSN que implemente el sistema operativo Contiki e internet. Dado que una WSN emplea distintos protocolos de comunicaciones y medios físicos que los de una red clásica de internet, el objetivo es el de diseñar un hardware capaz de adaptar esos medios físicos para que puedan interconectarse, a la vez que trabajar en el sistema operativo para hacerlo totalmente funcional en dicho hardware y lograr que los protocolos para WSN que utiliza Contiki sean compatibles con los que se emplean en internet.

IMG_20150427_143036

De esta forma, el resultado final será una plataforma capaz de integrarse por un lado en una WSN (actuando como nodo si es preciso gracias a varios puertos de expansión donde podrán conectarse diversos tipos de sensores) y por otro con un router de una red de internet, pudiendo enviar y recibir datos libremente entre ambas redes.

Thesis: Operating Systems dynamic optimization for Wireless Sensor Networks
Posted on by Roberto Rodríguez

Author: Roberto Rodriguez-Zurrunero

Advisor: Alvaro Araujo Pinto

Synopsis:  Wireless Sensor Networks are composed by multiple tiny nodes with limited resources. It is very important to manage the nodes operation as best as possible. This way it could be possible to improve the global performance with these limited resources. Therefore, an Operating System (OS) may be used to control the hardware and provide hardware abstraction to applications. The basic functionalities of an OS include resource abstractions for various hardware devices, interrupt management, task scheduling, concurrency control, and networking support. With these OS services the developers may program high-level applications independent of the underlying hardware and improving the nodes management. A traditional OS could not be embedded on WSN because they are used on systems with plenty of resources and different requirements. In WSN the resources are limited so an OS should manage them the best possible and it should involve the less overload possible in memory and CPU usage.

This thesis deals with the OS for WSN field. The goal is to take advantage of dynamic optimization of OS to improve some specific WSN parameter such as energy efficiency, processing capacity, flexibility, reliability, security and networking.

Sistemas Operativos para Redes de Sensores Inalámbricas
Posted on by Roberto Rodríguez

En los últimos años ha habido un gran crecimiento en el desarrollo y despliegue de Redes de Sensores Inalámbricas (WSN). Para ello se han utilizado multitud de plataformas hardware para cada aplicación específica, lo cual imposibilita la compatibilidad software entre aplicaciones.

Por ello hemos decidido comenzar una línea de investigación en sistemas operativos (OS) para redes de sensores inalámbricas, donde los recursos son muy limitados. Asimismo se pretende mejorar la eficiencia de las aplicaciones en redes de sensores con las herramientas que proporciona un sistema operativo.

Actualmente existen varios sistemas operativos orientados a redes de sensores inalámbricas y el objetivo es utilizarlos como base de cara a mejorar su funcionalidad para desarrollos futuros. Hay sin embargo multitud de retos para investigar en este campo, como pueden ser: gestión orientada a bajo consumo, interfaces de usuario para desarrolladores, compartición de recursos entre nodos, implementación de múltiples protocolos radio, algoritmos de tiempo real, personalización del sistema por el desarrollador, optimización automática en tiempo de ejecución…

Por ello, estamos trabajando con el sistema operativo Contiki OS para investigar estos retos que se plantean y desarrollar nuevas funcionalidades que se puedan aplicar a futuros despliegues de redes de sennsores.

 

WSN hardware platforms
WSN hardware platforms

An ultra-low wake-on radio receiver for Wireless Sensor Networks
Posted on by Roberto Rodríguez

An ultra-low power wake-on receiver has been designed, simulated, implemented and tested. This receiver has been developed for Wireless Sensor Network exploting the sleep mode of the nodes to reduce the average power consumption.

There are some wake-on devices in the literature, but they most lack on flexibility and power consumption. Therefore this receiver has been designed for multiple scenarios to make it easily integrable in any Wireless Sensor Network. A prototype was implemented in PCB using standard components and testing the prototype provides very good operating results, reducing the power consumption of a node up to 1000 times.

Wake-on receiver