57 research outputs found

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

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    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

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

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    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

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    to be published on Communication in Applied and Industrial Mathemathics

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

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    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

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    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
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