Current research activities

Satellite communications network of excellence

SatNEx is a network of excellence in the 6^th Framework Programme on Research, Technological Development and Demonstration. Its primary goal is to achieve long-lasting integration of the European research in satellite communications and to develop a common base of knowledge. Through co-operation of excellent universities and research organisations with outstanding expertise in satellite communications, SatNEx builds a European virtual centre of excellence in satellite communications and contributes to the realisation of the European Research Area.

SatNEx started in July, 2003 and finished in 2005, but continued with SatNEx II until October 2009. ESA then financed SatNEx III.

Activities for this research include:

• Measuring and modeling a Wi-Fi channel
• Packet loss in TCP hybrid wireless networks
• Packet loss in TCP hybrid wireless networks
• Simulating Dynamic Bandwidth Allocation on Satellite Links, a paper that describes an implementation of DAMA protocols for ns-2
• Transport layer protocols and architectures for satellite networks
• Resource management in satellite networks, Chap. 8.5.1 Redundant codes in hybrid networks
• Resource management in satellite networks, Chap. 9.3 Cross-layer interaction between TCP and physical layer
• Communications and networking over satellites: SatNEx experimental activities and testbeds

Remote Instrumentation in Next-generation Grids

RINGrid is an SSA project, part of European Community's 6^th Framework Programme, which started in October 2006. Its main reasearch area regards exploiting synergy between remote instrumentation and next-generation high-speed communications networks and grid infrastructures, with the aim of promoting egalitarian access to European e-Infrastructure opportunities for both scientific and business groups of users.

Interactive Media with Personal Networked Devices

InterMedia is a Network of Excellence in the 6^th Framework Programme on Research, Technological Development and Demonstration which started in October 2006. It is centred on Audio Video systems and applications convergence, in particular in home environments with homes as spaces of convergence, and for nomadic users with advanced mobile devices as points of convergence. The aim is evolving from the home-centric or device-centric approaches to a user-centric convergence. The medium is a personalised interface in the form of a flexible wearable platform that supports dynamic composition of wearable devices, and ad hoc connection to devices in the environment, a continuous access to multimedia networks, as well as adaptation of content to devices and user context.

Activities for this research include:

• Measurement-based frame error model for simulating outdoor Wi-Fi networks with downloadable measurements (also available on CRAWDAD) and a reference implementation of the proposed model.

Free software and research

I advocate the use of free software in research environments in Italy, starting from the research institute where I work. I am a member of Associazione software libero, an Italian associate of the Free Software Foundation Europe whose purposes are the diffusion of free software in Italy and a correct information on these topics.

I wrote an essay illustrating why free software is connatural with research, and how to encourage the use of free licenses for software written by research institutions. I also wrote an overview of software licenses and their suggested usage.

Past research activities

Software infrastructures for mobile ad hoc networks in difficult environments

ISMANET is a research project that aims at realising a software infrastructure for MANETs (mobile ad hoc networks), and at interconnecting them using satellite links. A prototype will be built on top of this infrastructure, useful for environmental emergency situations.

The project is financed under the agreement between MIUR and CNR (Legge 449/97 - Fondo speciale per lo sviluppo della ricerca di interesse strategico - D.D. n. 1694/Ric. del 27/11/2002 - Settore tematico: Piattaforme ITC abilitanti complesse ad oggetti distribuiti). It started in 2003 and ended in 2007.

Activities for this research include:

• Building an ad hoc network coupled with a satellite link
• Maximising single connection TCP goodput by trading bandwidth for BER
• Analysing TCP startup behaviour on wideband satellite channels without errors
• Measurements and packet error and packet loss statistics on a Wi-Fi channel
• Packaging simulation results with Costglue
• Bluetooth and Wi­Fi wireless protocols: a survey and a comparison
• Experimental results with forward erasure correction and real video streaming in hybrid wireless networks
• Frame error model in rural Wi-Fi networks with downloadable measurements

The GAliLEO satellite simulator

A simulator for Low Earth Orbit satellite constellations that I contributed to design and implement in Java. This project was closed for lack of funding. A short presentation (10 slides, 500KB) and a paper are available. GaliLEO has its own page.

Activities for this research include:

• Modeling and simulation environment for satellite and terrestrial communication networks
• Service efficient network interconnection via satellite - EU COST Action 253

The FODA/IBEA satellite access method

FODA/IBEA is a system for synchronous and asynchronous data satellite transmission able to counter the signal attenuation due to bad atmospheric conditions. The FODA/IBEA system was designed at CNUCE (now ISTI), an institute of CNR in Pisa, Italy. This project requires funding for engineering and marketing. I wrote about it in several scientific papers:

• FODA/IBEA-TDMA: a flexible fade countermeasure system for integrated services in user oriented networks
• Practical experiences in interconnecting LANs via satellite
• Comparison between distributed and centralised demand assignment TDMA satellite access schemes
• Experimental results of a demand-assignment thin route TDMA system
• Quality estimation of PSK modulated signals
• Delay analysis for interlan traffic using two suitable TDMA satellite access schemes
• Fade Countermeasure Using Signal Degradation Estimation for Demand-Assignment Satellite Systems

Traffic models and algorithms for next generation IP networks optimization

TANGO is a research project that aims at contributing to the realization of a methodology for the design, dimensioning, configuration and management of next-generation, multiservice IP networks, featuring advanced traffic control capabilities and QoS guarantees to the end users. To this end, TANGO will develop new modeling and optimization tools (both analytical and simulative). The availability of these tools will allow operators of both telecom and computer networking areas (carriers, companies, ISPs) to better design their networks, thanks to more advanced managing and configuration algorithms; also, these tools will provide remarkable advantages both in terms of cost and fee reductions, and in terms of a better user-perceived QoS.

TANGO will address multi-layer Internet networks, where the actual IP layer is supported by an MPLS (Multi Protocol Label Switching) layer, in its turn carried over a WDM optical infrastructure, with flexible wavelength allocation (GMPLS); furthermore, it will be assumed that the network employs DiffServ (Differentiated Services) policies at the IP layer: the Core Network will feature heterogeneous domains, managed by different providers, while the Edge Network will adopt different technologies, with an ever-growing use of wireless technologies.

The project ended in 2004.

Activities for this research include:

• Simulation of a TCP satellite scenario

Modelling and simulation tools for research
in emerging multi-service telecommunications

COST is a framework for scientific and technical cooperation, allowing the coordination of national research on a European level. COST Actions consist of basic and precompetitive research as well as activities of public utility. COST Action 285 objectives were the realization or improvement of simulation tools for telecommunications. The last meeting was held in March, 2007.

The first meeting was held in March, 2003, and its second one in September, when I a illustrated my past simulation activities. Here are some photographs.

Activities for this research include:

• Categorising flows of TCP packets
• Packaging simulation results with Costglue
• A tool for packaging and exchanging simulation results
• A tool for packaging and exchanging simulation results
• Modeling and simulation tools for emerging telecommunications networks
• Recent advances in modeling and simulation tools for communications networks and services
• Storing and exchanging simulation results in telecommunications
• CostGlue: simulation data exchange in telecommunications
• Definition of a metadata XML schema for the CostGlue, an archiver software for storing huge quantities of scientific data (technical report).

Broadcast in error-prone wireless environments

BREW is a CNR curiosity-driven research project financed by ISTI. The problem of finding an efficient broadcast schedule in multihop networks which minimizes the client expected delay, that is, the average amount of time spent by a client before receiving the item he needs, is called the Broadcast Problem. An alternative problem which approximates the first one is Multi-Channel Data Allocation with Flat Broadcast Per Channel Problem.

The purpose of this research is to find efficient ways to solve the problem on error-prone channels, by studying a model of a terrestrial wireless channel. The project ended in 2006.

Activities for this research include:

• Data broadcasting on error-prone wireless channels
• Allocating data for broadcasting over wireless channels subject to transmission errors