A new FANET simulator for managing drone networks and providing dynamic connectivity

In the last decade, the attention on unmanned aerial vehicles has rapidly grown, due to their ability to help in many human activities. Among their widespread benefits, one of the most important uses regards the possibility of distributing wireless connectivity to many users in a specific coverage area. In this study, we focus our attention on these new kinds of networks, called flying ad-hoc networks. As stated in the literature, they are suitable for all emergency situations where the traditional networking paradigm may have many issues or difficulties to be implemented. The use of a software simulator can give important help to the scientific community in the choice of the right UAV/drone parameters in many different situations. In particular, in this work, we focus our main attention on the new ways of area covering and human mobility behaviors with the introduction of a UAV/drone behavior model to take into account also drones energetic issues. A deep campaign of simulations was carried out to evaluate the goodness of the proposed simulator illustrating how it works

A Competitive Approach for Designing Multi-Antenna Cognitive Access Networks

Non

Joint control of bandwidth and playout-delay for streaming traffic over faded links (Best Paper Award)

In this paper we develop an optimized control strategy for the connection bandwidth maximization over a time varying wireless channel, by jointly controlling the adaptive source rate and the client/playout buffering policy with constraints on the maximum connection bandwidth allowed at the Application (APP) layer, the queue-capacities available at the Data-Link (DL) layer and the average and peak transmit energies sustained by the Physical (PHY) layer. The main feature of the approach we follow lies in the fact that the maximization of the throughput is performed with respect to the channel state information as well as the occupancies of the transmitter and receiver buffers, taking into account also for the need to optimize the playout buffer service so to reduce the stream-jitter provided to the final user. The resulting optimal controllers operate in a Cross-Layer (CL) fashion that involves the APP, DL and PHY layers of the underlying protocol stack. Via a parameter-depending optimization we are able to handle the jitter of the stream provided to the final user without significant impact on the bandwidth performances. The carried out numerical tests give insight into the tradeoff among average throughput, delay and jitter attained by the optimized controllers. ©2010 IEEE

Optimized joint bandwidth and playout control for streaming-traffic over wireless-channels

to be published on Communication in Applied and Industrial Mathemathics

Multi-Antenna IR-UWB Noncoherent ML Synchronization for Multipath Wideband Channels

In this contribution, the problem of the Synchronization for Ultra Wideband Impulse Radio (UWB-IR) systems, through the adoption of a multi-antenna platform working on multipath faded channels, is afforded. In this regard, we propose a novel UWB-IR synchronizer devoted to jointly estimate (according to the Maximum Likelihood (ML) critérium) the arrival times and their (Poisson distributed) number, composing a typical UWB-IR multipath faded channel. Such estimate is effected without any knowledge on the value of the channel paths (noncoherent ML synchronizer). The architecture of such Synchronizer is based on a Single-Input Multiple-Output (SIMO) platform, instead of a Multiple-Input Multiple-Output MIMO one, according to a previous result in the Literature. Related performance of this joint ML estimation is expressed in closed via the Cramer-Rao bound (CRB) and is tested by simulations, under acquisition and tracking conditions. © 2007 IEEE

Generalized Access for MIMO Cognitive Radios

Main goal of this work is to give insight on the possibile performance improvement arising in the wireless local and/or ad-hoc access from the synergic cooperation of two emerging paradigms, e.g., Multi-Antenna and Cognitive radios. As application scenario, we consider both the faded uplink of a WLAN working in infrastructure-mode, where noncooperative Multi-Antenna cognitive radios attempt to join to a (possibly Multi-Antenna) Access Point (AP) and an ad-hoc scenario where each node can communicate with each free node. The target can be twofold and two different approaches are considered. The first is the competitive maximization of own access throughput in the presence of Multiple-Access Interference (MAI) induced by the other accessing terminals, the second one is the BER minimization. Being the radios cognitive, they are capable to autonomously learn the ambient-context and, then, self-configure their access strategy via suitable power-allocation that is time-frequency-code- space signal-shaping. Furthermore, a generalized approach is developed that allows the node to access with a (possibly hybrid) scheme to the medium by combining different x-DMA strategies under QoS-guaranteed access policy. ©2008 IEEE

On the Information Rate of Multi-Antenna Systems with Isotropic Unitary input signals in the presence of Channel Estimation Errors

This correspondence focuses on the evaluation of the information rate conveyed by block-faded pilot-based multiple-input multipleoutput (MIMO) systems when the input signals are isotropic–unitary (IU)- distributed and imperfect (e.g., error-affected) channel estimates are available at receiver and transmitter. Main contributions may be so summarized. First, we develop closed-form analytical formulas for the computation of the ergodic information rate conveyed by the considered MIMO systems equipped with a large number of transmit antennas. Second, we point out that no rate gain may be accomplished by shaping the transmitted streams on the basis of (possibly partial) channel state information (CSI) so that the feedback link becomes, indeed, useless when the system is block faded and fed by IU-distributed input signals. Third, we compare the obtained information rate with those supported by the corresponding MIMO systems fed by Gaussian-distributed input signals [11] for various values of the mean-squared error (MSE) impairing the available MIMO channel estimates. So doing, we gain some insight about the operating conditions where actual implementation of a feedback link may be justified by the resulting improvement in the rate conveyed by the overall system