Carlos Miguel Tavares Calafate

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We present a programming interface, called PICA, which aims to reduce the production cycle duration for communication protocols. It offers a user-friendly API that is very intuitive and that covers the major necessities which these protocols may have. Since most research is done in the Linux operating system, it also aims to reduce very significantly the(More)
— Ubiquitous computing refers to making many computing devices available throughout the physical environment, while making them effectively invisible to the user. To further increase the applicability of ubiquitous computing, minimizing energy consumption and hardware cost are mandatory in real world applications. In this paper we present our platform(More)
This paper addresses the problem of video streams transmission in 802.11b based Mobile Ad-hoc Networks (MANETs). Through the study of the delivery of a live encoded video stream, we expose the characteristics of different routing protocols and the infeasibil-ity to provide QoS. The analysis shows the impact of a MANET on H.264 real-time video flows in terms(More)
— Deploying and testing Vehicular Ad hoc Networks (VANETs) involves high cost and intensive labor. Hence simulation is a useful alternative prior to actual implementation. Most works found in the literature employ very simplistic Radio Propagation Models (RPMs), ignoring the dramatic effects presented by buildings on radio signals. In this paper, we present(More)
In recent years, new applications, architectures, and technologies have been proposed for vehicular ad hoc networks (VANETs). Regarding traffic safety applications for VANETs, warning messages have to be quickly and smartly disseminated in order to reduce the required dissemination time and to increase the number of vehicles receiving the traffic warning(More)
—Knowing the density of vehicles in a vehicular communications environment is important, as better opportunities for wireless communication can show up. This paper studies the importance of predicting the density of vehicles in vehicular environments to take decisions for enhancing the dissemination of warning messages between vehicles. Moreover, we propose(More)
The IEEE 802.11e technology is receiving much interest due to the promising enhancements it will offer to wireless local area networks in terms of QoS support. Until now, research has focused on single hop, access point based environments , which are the most common. In this work we review the enhancements proposed in the last IEEE 802.11e draft (version(More)