Supporting voice traffic in existing WLANs results extremely inefficient, given the large overheads of the protocol operation and the need to prioritize this traffic over, e.g., bulky transfers. In this paper we propose a simple scheme to improve the efficiency of WLANs when voice traffic is present.

This is the kick-off meeting of the iJOIN EU FP7 project. It will consist of a series of presentations of work packages 2-4 intended to shape the first steps of the project. WP2-4 will be presented during 90 minute slots by each Work Package leader.

A thorough understanding of the power consumption behavior of real world wireless devices is of paramount importance to ground energy-efficient protocols and optimizations on realistic and accurate energy models. This paper provides an in-depth experimental investigation of the per-frame energy consumption components in 802.11 Wireless LAN devices. To the best of our knowledge, our measurements are the first to unveil that a substantial fraction of energy consumption, hereafter descriptively named cross-factor, may be ascribed to each individual frame while it crosses the protocol/implementation stack (OS, driver, NIC). Our findings, summarized in a convenient new energy consumption model, contrast traditional models which either neglect or amortize such energy cost component in a fixed baseline cost, and raise the alert that, in some cases, conclusions drawn using traditional energy models may be fallacious.

Visible Light Communication (VLC) is an emerging technology in which Light Emitting Diodes (LEDs) transport information wirelessly, using the visible light spectrum. While most of the research on VLC has focused on wideband white LEDs used in ambient illumination, narrowband and colored LEDs have received little attention. Short-range free-space optical communication based on narrowband LEDs as visible light transmitters and receivers enable a variety of applications, a scenario we refer as LED-to-LED communication. In this work, we introduce the communication and networking protocols of LED-to-LED communication. Our work addresses fundamental challenges such as efficient collision detection medium access protocol and elimination of light flicker. We build a prototype and demonstrate bi-directional data exchange in a network of up to four LEDs. We further study the trade-offs in the system design and measure the achievable bit-rate and transmission distances

The international networking research community has begun to focus on ideas for a next generation Internet architecture. Before developing a next generation architecture, however, it seems appropriate to understand what exactly the problems are with the current Internet architecture. There seems to be widespread agreement that mobility and security are the primary problems stressing the current Internet, but exactly what the problems with mobility and security are, and in particular, whether the problems are architectural in nature, is under dispute. In this lecture series, we examined the mobility and security with the intention of understanding the current architecture and what might be done for a next generation architecture.

Telefonica Open Research Day 2008

Research is the process of exploration of new ideas and allows Telefonica to look into the future, working on tomorrow's problems and finding solutions that people can only dream about today.

As a result Telefonica is investing in bringing together incredibly passionate talented people with different view points (nationalities, disciplines, backgrounds) to follow their dreams, create new subjects and as a result new worlds for Telefonica's customers.

More information about Alex Bikfalvi

Ralf Steinmetz is one of the world experts in multimedia and P2P applications, is the author of one of the most referenced books in the area, and he has received the ACM Multimedia Award.

Since early 1996 Ralf Steinmetz has been a professor at the dept. of Electrical Engineering and Information Technology as well as at the dept. of Computer Science of the Darmstadt University of Technology, Germany. There he is in charge of a chair position as managing director of the "Multimedia Communications Lab". From late 1996 until late 2001 he directed the GMD/Fraunhofer Integrated Publications and Information Institute. In 1999 he founded the Hessian Telemedia Technology Competence Center (httc e.V.). On whose board he has since served as chair. He is also one of the directors of the Information Transfer Office at the university. From 2002 to 2004 as dean he managed the department.

Multimedia Communications, involving traditional media such as audio, video, text, 2D graphics, have become parts of everyday e-life. New digitalmedia, such as Virtual Reality and Haptics, have now added new dimensions to multimedia tele-collaboration. This presentation will introduce basic issues on Distributed and Collaborative Virtual Environments, where the feeling of touch (haptics) and its transmission over networks is becoming essential. Various applications will be described ranging from industrial training to e-commerce to medical education. Effects of networking =93quality of experience on collaborative hapto-virtual applications will be discussed and methods for delay and jitter compensation will be described.

More information about Marco Gramaglia   The seminar will be conducted in English