Projeto de redes Ad Hoc sem fio ciente de topologia

Abstract

The main hypothesis underlying this work can be briefly stated as follows: The information concerning the topology induced by the connectivity of Wireless Ad Hoc Networks is relevant for both planning their deployment and for optimizing their operation. Thus, we are interested in how to apply different concepts and metrics related to the topology of three different network models: (i) wireless sensor networks (WSNs), (ii) mobile ad hoc networks (MANETs), and (iii) vehicular ad hoc networks (VANETs). These three models correspond to a wide variety of network topologies characteristics, from typically static or nearly static topologies (WSNs), to highly dynamic topologies such as the ones present in VANETs. The main goals of this work are: (i) the proposal of topology models, (ii) the proposal of new topology metrics useful in the design or in the operation of the network, (iii) the design of distributed estimators of topology-related features, and (iv) the design of topology-aware algorithms suitable for improving the performance of wireless ad hoc networks. The main contributions accomplished in this work can be summarized as follows: an expressive topology model able to describe a wide variety of deployment strategies for WSNs; a topology-related feature estimator derived from the betweenness metric, which has proven more suitable for representing the energy depletion related to sensor relay task in WSNs. In collaboration with a master student it was developed a distributed algorithm to calculate this metric. This metric was used to design two different routing algorithms: the first, aims to improve the data fusion task in WSNs, and the second, aims to fairly balance the energy among the relay nodes in a WSN. In the field of MANETs, it was developed a new localization system for Internet capable devices, based on A-GPS technology, which offloads the GPS raw signal data to the cloud. It was shown that this technique is able to reduce the energy consumption up to 80% when compared to traditional A-GPS. To tackle with the highly dynamic topologies present in VANETs, it was proposed the use of a cooperative target tracking solution in order to track the quick changes of the topologies due to the high velocity of the vehicles.