Topology and Time Synchronization algorithms in wireless sensor networks

English: Wireless sensor networks are an active field of research in computer science. The Wisebed project, formed by many European universities, tries to fill the gap between theory and practice, making a platform-independent library of algorithms named Wiselib, and building a testbed in each university accessible through internet. In this project, different topology and time synchronization algorithms are analyzed and implemented into the Wiselib library. These algorithms are later tested through simulation and in the UPC testbed. Theoretical and real life properties of the algorithms are discussed and compared. --- Les xarxes de sensors inalàmbrics són un camp actiu de recerca en informàtica. El projecte Wisebed, format per diverses universitats europees, intenta omplir el buit entre teoria i pràctica, creant una llibreria d'algorismes anomenada Wiselib i construint xarxes de sensors a cada universitat, accessibles per internet per realitzar proves. En aquest projecte, alguns algorismes de topologia i de sincronització són analitzats i implementats en la llibreria Wiselib. Aquests algorismes es proven mitjançant simulacions i en la xarxa de la UPC. Es discuteixen i comparen propietats teòriques i reals d'aquests algorismes

A Systematic Approach to Constructing Families of Incremental Topology Control Algorithms Using Graph Transformation

In the communication systems domain, constructing and maintaining network topologies via topology control (TC) algorithms is an important cross-cutting research area. Network topologies are usually modeled using attributed graphs whose nodes and edges represent the network nodes and their interconnecting links. A key requirement of TC algorithms is to fulfill certain consistency and optimization properties to ensure a high quality of service. Still, few attempts have been made to constructively integrate these properties into the development process of TC algorithms. Furthermore, even though many TC algorithms share substantial parts (such as structural patterns or tie-breaking strategies), few works constructively leverage these commonalities and differences of TC algorithms systematically. In previous work, we addressed the constructive integration of consistency properties into the development process. We outlined a constructive, model-driven methodology for designing individual TC algorithms. Valid and high-quality topologies are characterized using declarative graph constraints; TC algorithms are specified using programmed graph transformation. We applied a well-known static analysis technique to refine a given TC algorithm in a way that the resulting algorithm preserves the specified graph constraints. In this paper, we extend our constructive methodology by generalizing it to support the specification of families of TC algorithms. To show the feasibility of our approach, we reneging six existing TC algorithms and develop e-kTC, a novel energy-efficient variant of the TC algorithm kTC. Finally, we evaluate a subset of the specified TC algorithms using a new tool integration of the graph transformation tool eMoflon and the Simonstrator network simulation framework.Comment: Corresponds to the accepted manuscrip

Highway construction in Wireless Sensor Networks

English: Wireless sensor networks are a rapidly growing field of study with many open research topics. The aim of this project is to build a hierarchy of clusters in wireless sensor networks and to communicate them through distinguished paths. Those paths are known as highways, and simplify higher level node inter-communication while reducing energy and memory requirements. To achieve this goal several distributed algorithms were designed and tested either in simulators or in real hardware. The message delivery rate, through highways, measured in hardware was close to 70\% and it effectively served as base for a higher level network module to make end to end communication between every node of the connected network. This opens a way for the development of more algorithms to make wireless sensor networks communications on large deployments effective and trouble less