Showing papers by "Luigi Alfredo Grieco published in 2009"

Secure Wireless Multimedia Sensor Networks: A Survey

Abstract: Wireless Multimedia Sensor Networks (WMSNs) are used in many application domains, such as surveillance systems, telemedicine and so on. In order to ensure a broad deployment of such innovative services, strict requirements on security, privacy, and distributed processing of multimedia contents should be satisfied, taking also into account the limited technological resources (in term of energy, computation, bandwidth, and storage) of sensor nodes. Thus, with respect to classic Wireless Sensor Networks, the achievement of these goals is more challenging due to the presence of multimedia data, which usually requires complex compression and aggregation algorithms. In order to provide a unifying synthesis on the last achievements, this survey summarizes the main findings on secure WMSNs proposed in the literature and forecasts future perspectives of such a technology.

A simulation-based performance evaluation of Wireless Networked Control Systems

Abstract: A Wireless Networked Control System exploits a shared wireless network to logically link its sub-systems. Due to the peculiarities of the wireless channel, it is important to understand in which measure the Quality of Service provided by the communication infrastructure affects the Quality of Control. The aim of this work is to analyze the performance of a Wireless Networked Control System based on the IEEE 802.11 MAC. For that purpose, a model of such a system has been built using the ns-2 simulator and the impact of MAC parameters on the system dynamics has been evaluated. Simulation results have highlighted strengths and limitations of this kind of Wireless Networked Control System.

An analysis of packet sampling in the frequency domain

Abstract: Packet sampling techniques introduce measurement errors that should be carefully handled in order to correctly characterize the network behavior. In the literature several works have studied the statistical properties of packet sampling and the way it should be inverted to recover the original network measurements. Here we take the new direction of studying the spectral properties of packet sampled traffic. A novel technique to model the impact of packet sampling is proposed based on a theoretical analysis of network traffic in the frequency domain. Moreover, a real-time algorithm is also presented to detect the spectrum portion of the network traffic that can be restored once packet sampling has been applied. Preliminary experimental results are reported to validate the proposed approach.

A multichannel collision free MAC protocol for wireless ad hoc networks

Abstract: Thinking of multiple frequency channels in wireless ad hoc networks can significantly improve the throughput if advanced MAC protocols are employed. The efficiency of multichannel protocols mainly depends on the channel assignment strategy, which has to assure both fairness and low signaling overhead. Taking into account these needs, the present work proposes a new multichannel MAC protocol, based on the Balanced Incomplete Block Design (BIBD) theory. In details, the protocol we propose is time slotted, collision free, and assures a fair distribution of both available frequency channels and time slots, thanks to the BIBD resolvability feature. Exploiting the peculiarities of BIBD, procedures for handling network topology modifications with a low overhead have been also developed. Finally, analytical results have shown very high channel utilization, efficiency, and global energy saving.

Evaluation of a bibd based directional mac protocol for wireless ad hoc networks

Abstract: The use of directional antennas in wireless ad hoc networks can significantly improve global performance due to a high spatial channel reuse. Nevertheless, its introduction poses new location dependent problems related to the MAC protocol. In this paper, the Balanced Incomplete Block Design theory has been exploited to develop a new MAC protocol for wireless ad hoc networks using directional antennas. It is a time slotted protocol, which is highly scalable. Moreover, it can provide a high number of concurrent communications, depending on the number of directional antennas mounted on each node, great fairness in bandwidth sharing and significant energy saving. In particular, energy saving provided by our scheme is consistently higher compared to those of usual directional MAC protocols for the following reasons. Firstly, control packets are sent only over fairly selected beams rather than over all the available ones. Secondly, our protocol provides a filtering, i.e. a fair selection, of the nodes that can try the access to the medium in each time slot. Simulation results validate the advantages of our protocol by proving high spatial reuse, great fairness and significant energy saving and by showing that it improves the overall system performance.