Ermanno Pietrosemoli

Very long distance wi-fi networks

802.11 Wi-Fi technology is commonly used for creating wireless networks with a range of about one hundred meters. With careful planning and proper antennas, this same equipment can be used to make point-to-point links of hundreds of kilometers. This paper presents a successful 279 km link made by wireless experts in Venezuela, and a permanent 133 km test network in northern Italy for ongoing research.

Supporting cloud deployment in the Guifi.net community network

Community networking is an emerging model of a shared communication infrastructure in which communities of citizens build and own open networks. Community networks offer successfully IP-based networking to the user. Cloud computing infrastructures however, while common in todays Internet, hardy exist in community networks. We explain our approach to bring clouds into the Guifi.net community network. For this we have started integrating part of our cloud prototype into the Guifi.net community network management tools. A proof-of-concept cloud infrastructure is currently under deployment in the Guifi.net community network. Our long term vision is that the users of community networks will not need to consume cloud applications from the Internet, but find them within the community network.

A Survey of TV White Space Measurements

Unused spectrum in the television band (so-called TV white space) has the potential to provide new spectrum for access to information and communication services in developing countries. This claim has been subject to a variety of measurement studies. The purpose of this paper is to survey these studies to better characterize the spectrum that is provided by TV white space. We discuss some of the challenges to such studies and characterize the available TV white space spectrum in terms of the total volume that is available.

WhispPi: White space monitoring with Raspberry Pi

Recently a lot of attention has been given to the use of TV White Spaces for rural communications. Several monitoring campaigns have been carried out to measure spectrum occupancy worldwide, concluding that most of the spectrum is underutilized. In this paper we present the design and implementation of a low cost system to measure spectrum occupancy and to geo-tag the measurements to allow mobile measurement campaigns. The system is based on the Raspberry Pi system on chip and on an affordable spectrum analyser. After calibrating the system against a professional spectrum analyser, we measured the spectrum occupancy in urban and rural Venezuela, showing that there is plenty of vacant UHF TV spectrum.

An assessment study on white spaces in Malawi using affordable tools

For rural areas, wireless is the only viable alternative for providing affordable telecommunications services. One limiting factor to the growth of wireless broadband penetration is the lack of available spectrum. White Spaces broadband uses gaps in spectrum bands that have been reserved for TV broadcasts. These frequencies offer significant capacity to help alleviate pressures on existing wireless networks and allow connectivity in remote areas due to their good propagation capabilities. This paper describes an assessment study on TV White Spaces availability in Malawi using affordable tools. The conclusion of the study is that 1) it is possible to assess the spectrum usage using low cost equipment 2) ample spectrum for TV White Spaces deployment is available in Malawi.

Cloud based patient prioritization as service in public health care

This paper proposes and evaluates the performance of a Cyber-healthcare system which is aimed at providing patient prioritization over the cloud as a public health service for the rural and urban communities of the developing world. The underlying cloud-based Internet-of-Things (IoT-Cloud) infrastructure is aimed to be implemented in the city of Lubumbashi in the republic Democratic Republic of the Congo (DRC) with the objective of setting up a community health care network around a mesh of health kiosks. We propose a deployment model for the proposed Cyber-healthcare system, and describe a patient prioritization process as part of its situation awareness component. The results obtained from an experimental prototype reveal the field readiness of the off-the-shelf bio-sensor technology used by the system, the performance achieved when using a solar powered subsystem, the relative communication capabilities provided by its protocols and the network engineering feasibility of the planned community health care network. The relative efficiency of using supervised machine learning compared to unsupervised machine learning when performing patient prioritization, is also revealed through two popular algorithms: Multivariate linear regression (MLR) and K-means clustering (KMC).

On the relevance of using affordable tools for white spaces identification

It is widely recognized that white spaces identification is an important milestone for the wide deployment of next generation cognitive wireless networks. However, spectrum holes detection tools used for white spaces discovery are still either in the infancy stage or too expensive to enable massive white spaces exploitation. Building upon cheap hardware equipment, this paper presents experiments conducted in the town of Trieste in Italy to sense the environment and find out which frequencies are not being used in a particular place and time-of-the-day. As a a step towards white spaces exploitation, we believe that our experimental frequency exploration is an important milestone upon which white spaces patterns recognition will be built with the aim of using these patterns in wireless network planning and management.

Energy-efficient Internet of Things monitoring with low-capacity devices

The Internet of Things (IoT) allows users to gather data from the physical environment. While sensors in public spaces are already widely used, users are reluctant to deploy sensors for shared data at their homes. The deployment of IoT nodes at the users premises presents privacy issues regarding who can access to their data once it is sent to the Cloud which the users cannot control. In this paper we present an energy-efficient and low cost solution for environmental monitoring at the users home. Our system is built completely with open source components and is easy to reproduce. We leverage the infrastructure and trust of a community network to store and control the access to the monitored data. We tested our solution during several months on different low-capacity single board computers (SBC) and it showed to be stable. Our results suggest that this solution could become a permanently running service in SBCs at the users homes.

Architecting a Low Cost Television White Space Network For Developing Regions

There has been a number of Television White Space (TVWS) deployments in developing regions, using equipment designed for the western market. In this paper we assess a solution that addresses three of the limiting factors of existing solutions: high cost, database dependence and high power consumption. We argue that as there is enough TVWS spectrum availability especially in rural areas in developing regions, we do not need to use any geolocation databases nor do we need a tight transmit spectrum mask. We propose a low cost and an energy efficient TVWS network device that uses an embedded linux board equipped with a miniPCI card operating in the TVWS frequencies, for which we test the RF performance and power consumption for comparison to those of a commercial TVWS equipment.

Deploying clouds in the Guifi community network

This paper describes an operational geographically distributed and heterogeneous cloud infrastructure with services and applications deployed in the Guifi community network. The presented cloud is a particular case of a community cloud, developed according to the specific needs and conditions of community networks. We describe the concept of this community cloud, explain our technical choices for building it, and our experience with the deployment of this cloud. We review our solutions and experience on offering the different service models of cloud computing (IaaS, PaaS and SaaS) in community networks. The deployed cloud infrastructure aims to provide stable and attractive cloud services in order to encourage community network user to use, keep and extend it with new services and applications.