Impact of realistic communications for fast-acting demand side management

The rising penetration of intermittent energy resources is increasing the need for more diverse electrical energy resources that are able to support ancillary services. Demand side management (DSM) has a significant potential to fulfil this role but several challenges are still impeding the wide-scale integration of DSM. One of the major challenges is ensuring the performance of the networks that enable communications between control centres and the end DSM resources. This paper presents an analysis of all communications networks that typically participate in the activation of DSM, and provides an estimate for the overall latency that these networks incur. The most significant sources of delay from each of the components of the communications network are identified which allows the most critical aspects to be determined. This analysis therefore offers a detailed evaluation of the performance of DSM resources in the scope of providing real-time ancillary services. It is shown that, using available communications technologies, DSM can be used to provide primary frequency support services. In some cases, Neighbourhood Area Networks (NANs) may add significant delay, requiring careful choice of the technologies deployed

Indoor positioning with 6LoWPAN

Máster en Internet de las Cosas, Facultad de Informática UCM, Departamento de Arquitectura de Computadores y Automática, Curso 2019/2020.El posicionamiento indoor no es un tema nuevo dentro del mundo de las tecnologías de la información. Sin embargo, existen múltiples formas de comunicación que intentan aprovechar sus particulares bondades para potenciar esta funcionalidad dependiendo del ecosistema donde se quiera utilizar. Por ejemplo, no se requiere la misma precisión si queremos guiar a una persona con movilidad reducida, o si nuestro objetivo es descubrir patrones de movimiento de personas en un centro comercial. Además, el consumo de batería en los diferentes dispositivos tampoco se comportaría de igual forma ni requeriría la misma atención en función del escenario de aplicación. Este trabajo se centra en un caso de uso muy habitual dentro del mundo industrial, que es el tracking de activos en una planta de manufactura. La tecnología 6LoWPAN, junto con el protocolo RPL diseñado específicamente para redes de bajo consumo de energía, nos presenta una oportunidad muy interesante para el estudio de este caso de uso. En este trabajo se realiza un estudio del funcionamiento del protocolo RPL que implementa el sistema operativo Contiki, con el fin de modificarlo para calcular las coordenadas de un nodo en función de sus nodos vecinos de los cuales se conocen sus coordenadas y su RSSI (Received Signal Strentgh Indication). Para ello, se utiliza el simulador Cooja como base para realizar las pruebas de la implementación y estudiar el comportamiento de la red en cuanto a los tiempos de convergencia de esta.Indoor positioning is not a new issue in the world of information technology. However, there are many forms of communication that try to take advantage of its particular benefits to enhance this functionality depending on the ecosystem where it will be used. For example, the same accuracy is not required if we want to guide a person with reduced mobility, or if our objective is to discover movement patterns for people in a shopping centre. Besides, the battery consumption in the different devices would not be the same either. This paper focuses on a very common case in the industrial world, which is the tracking assets in a manufacturing plant. The 6LoWPAN technology together with the RPL protocol designed specifically for low energy consumption networks, give us a very interesting opportunity to study this use case. In this project, a study of the functioning of the RPL protocol implemented by the Contiki operating system is carried out in order to modify it to calculate the coordinates of a node based on neighbors’ nodes whose coordinates and RSSI (Received Signal Strentgh Indication) are known. The Cooja simulator is used as a basis to test the implementation and study the behavior of the network in terms of convergence times.Depto. de Arquitectura de Computadores y AutomáticaFac. de InformáticaTRUEunpu

Highly reliable, low-latency communication in low-power wireless networks

Low-power wireless networks consist of spatially distributed, resource-constrained devices – also referred to as nodes – that are typically equipped with integrated or external sensors and actuators. Nodes communicate with each other using wireless transceivers, and thus, relay data – e. g., collected sensor values or commands for actuators – cooperatively through the network. This way, low-power wireless networks can support a plethora of different applications, including, e. g., monitoring the air quality in urban areas or controlling the heating, ventilation and cooling of large buildings. The use of wireless communication in such monitoring and actuating applications allows for a higher flexibility and ease of deployment – and thus, overall lower costs – compared to wired solutions. However, wireless communication is notoriously error-prone. Message losses happen often and unpredictably, making it challenging to support applications requiring both high reliability and low latency. Highly reliable, low-latency communication – along with high energy-efficiency – are, however, key requirements to support several important application scenarios and most notably the open-/closed-loop control functions found in e. g., industry and factory automation applications. Communication protocols that rely on synchronous transmissions have been shown to be able to overcome this limitation. These protocols depart from traditional single-link transmissions and do not attempt to avoid concurrent transmissions from different nodes to prevent collisions. On the contrary, they make nodes send the same message at the same time over several paths. Phenomena like constructive interference and capture then ensure that messages are received correctly with high probability. While many approaches relying on synchronous transmissions have been presented in the literature, two important aspects received only little consideration: (i) reliable operation in harsh environments and (ii) support for event-based data traffic. This thesis addresses these two open challenges and proposes novel communication protocols to overcome them