1,720,974 research outputs found
LIBERO: LIght Bias as effective countermeasure against EavesdROpper attacks
No full textVisible Light Communication (VLC) is expected to enable a wide range of applications in the next generation wireless networks. These applications are recognized as sensitive and prone to dangerous threats. So far, VLC research activities have been more focused on developing high data rate solutions and more robust systems for both indoor and outdoor applications, with a reduced focus on the security aspects. This is mostly due to the fact that VLC systems are based on short range and occurs in line of sight and it is then considered inherently secure by design. The specific characteristics of VLC systems make the traditional countermeasures adopted in radio-frequency-based systems not applicable, with a concrete need to conceive ad hoc solutions. Basing on these premises, in this work we consider a physical layer perspective by analyzing the intrinsic properties of visible light signals so as to develop a secure by design VLC system to be used in downlink. By exploiting the light bias, we guarantee an improved security level in respect of eavesdropper attack by granting also a good illumination level. A key aspect of this work is that the proposed solution does not rely on external devices or extra hardware
On the Impact of Mobility on the Underwater Optical IoT Architecture for Positioning and Communication
No full textThe use of Optical Wireless Communications is largely adopted in both indoor and outdoor applications. Recently, it is also extending to underwater scenarios, as an alternative technology to the acoustic one, which is traditionally adopted. Knowing more precisely the position of artifacts, technical/scientific instruments and operators in the marine environment increases the operational potential and consequently, the interest in the progress of knowledge is guaranteed. Furthermore, the possibility of operating in both shallow and deep waters and the opportunity to be a new underwater navigation system increases the possibility of success of underwater activities, in the context of the Internet of Underwater Things (IoUT). This paper introduces an underwater all-optical IoT network architecture for both communication and positioning tasks. We initially discuss the main issues for data transmission via underwater visible light communications, and present an IoUT schematic based on Light Emitting Diode (LED) devices accordingly deployed on the seabed and illuminating a given space of interest. Then, a simple but accurate fingerprinting-based localization approach is presented, able to estimate the position of an object moving within the space of interest (e.g., a diver or an Autonomous Underwater Vehicle). The positioning error is auto-adjusted in case of variable channel coefficients, mainly due to changes in water turbidity space distribution. The achieved results have been assessed in case of two different paths, where variable distances from the positioning/communication LEDs are assumed
INVISIBLE 2.0: An enhanced interference-based handover technique for visible light communications in vehicular networks
No full textSince the last decade, Visible Light Communication (VLC) has represented a huge capacity to complement conventional Radio Frequency (RF) technologies in plenty of applications. The credibility of VLC in terms of power consumption has always been compared to RF. In this work, in addition to addressing this issue through a detailed power model, the co-existence of VLC and the Long-Term Evolution (LTE) cellular network in a vehicular environment has been empirically investigated. The coordination of data transmission among different technologies is managed through a novel vertical handover mechanism, namely INVISIBLE 2.0. This technique is triggered by the error probability to meet the 3GPP requirements on packet reception ratio while endorsing VLC as the preferred technology bearer. We demonstrate that INVISIBLE 2.0 achieves a more stable latency, and energy efficiency based on extensive simulation results
Adaptive modulation control for visible light communication systems
Full text linkVisible light communication (VLC) builds on the dual use of lightening infrastructure for communication. Even though the advantages of VLC are well known, as emerging communication paradigm, some open issues still need to be addressed in order to rely on it as a robust communication system. First of all, external interference as an extremely varying signal impacting on the reliability of the VLC system needs to be analyzed. In this paper, we propose a system where the link conditions (in terms of signal-to-noise-ratio (SNR)) drive the modulation scheme and this procedure is managed through the use of an uplink/channel, to assure a feedback path. The receiver is in charge of choosing the modulation scheme matching the requirement in terms of error rate on the basis of the measured SNR after noise mitigation. The feasibility of the system and its effectiveness are evaluated by designing and implementing a complete bi-directional system. In particular, an uplink channel sending the information regarding the specific selected modulation technique has been implemented and the whole system is based on a fine synchronization approach in order to “track” in real time the most suitable modulation scheme. Experimental results show the effectiveness of a bi-directional system in order to implement an adaptive VLC system able to follow the environmental changes (in terms of interference and noise)
On the noise effect of fingerprinting-based positioning error in underwater visible light networks
No full textThis paper assesses the performance of a localization technique for underwater visible light networks. The proposed approach is based on a fingerprinting technique, collecting the channel impulse responses from different wireless optical signals in the visible range. A local database related to the power level distribution within a maritime environment is built and exploited to estimate user position, e.g., a diver moving in a given space for underwater fish monitoring. In this paper, we investigate on the noise effect on the localization accuracy in underwater scenarios and for different water turbidity coefficient and we demonstrate that the estimation error suffers on variable channel impulse responses. Different configuration parameters and environmental scenarios have been considered, showing that the LED transmitter deployment can be effective in the localization estimation. A comparison of the proposed localization approach to the traditional triangulation method has been finally carried out, showing the effectiveness of the fingerprinting-based solution for a lower number of LED transmitters
On the Reshape and Comparison of Medium Access Strategies for Infrared Indoor Uplink
No full textIn the framework of indoor optical wireless communications, a lot of attention has been paid to the downlink, usually implemented via the new paradigm of Visible Light Communication (VLC). On the other side, the uplink communication process is often dropped and the access in uplink is usually performed by other available wireless technologies, such as the Radio Frequency (RF). In this work, we analyze and compare the performance offered by different access approaches in the context of uplink infrared (IR) communication. Specifically, we consider traditional Time Division Multiple Access, ALOHA and Carrier Sensing Multiple Access with Collision Avoidance approaches, potentially reshaped for IR indoor scenario. Indeed, due to the mainly line-of-sight propagation features of the optical wireless channel, CSMA/CA is rephrased so as to work due to the impossibility of users of applying a true (RF-like) sensing mechanism. We report the performance in terms of efficiency and access probability by considering the impact of different parameters as channel capacity, number of users and burstiness of the services/applications
Communication Technologies Enabling Effective UAV Networks: A Standards Perspective
No full textRecent developments in the unmanned aerial vehicles (UAVs) field have made evident the need for a standardization process of the communication technologies supporting direct information exchange, thus enabling UAV-to-UAV networking. We consider this is necessary to achieve all sorts of cooperative tasks requiring real-time (or near-real-time) synchronization, including swarm formation and collision avoidance. In this article, we therefore argue in favor of introducing a new standard that would address this specific area, highlighting why current technologies are not adequate, what the different steps toward rapid standardization are, and which lessons have been learned from related fields, namely the vehicular and robotic environments, in the past few years
A social internet of vehicles sharing SIoT relationships
No full textIn recent years, the concept of social networking combined with the Internet of Vehicles has brought to the definition of the Social IoV (SIoV) paradigm, i.e., a social network where every vehicle is capable of establishing social relationships in an autonomous way with other vehicles or road infrastructure equipment. In SIoV, social networking is applied to vehicular networks according to how social ties are built upon, i.e., either among vehicles or humans. This creates a twofold nature of SIoV i.e., both based on human social relationships, and as an instance of the Social Internet of Things (SIoT). This twofold nature of SIoV is not in contrast with itself, but allows to distinguish different applications and use-cases. This paper analyzes the SIoT-based social relations in a vehicular network scenario for establishing a Social Internet of Vehicles and providing insights on this growing research area
MuSLi: A multi sensor LiDAR detection for C-V2X networks
No full textObstacle detection is a tool adopted in vehicular safety applications, aiming to detect a moving obstacle in an area of interest with the highest accuracy. Different sensors are used for this aim, such as LiDAR devices mounted on board of a vehicle that capture images of the surrounding environment. Extending the number of LiDAR sensors can be useful to improve the obstacle detection accuracy, since multiple images are captured from different distances and directions, and this represents an interesting approach, specially in case of dense networks with cooperative nodes. In this paper we present MuSLi technique, aiming to (i) provide an accurate obstacle detection and (ii) forward alert messages to other cars in the network, in case of correct detection of a pedestrian crossing the street. MuSLi relies on the connected content islands scenario, where each vehicle defined as a content island subscribes to a service in order to receive and share published messages. Specifically, the road safety service allows the detection of an obstacle through multiple LiDAR sensors from neighboring cars. Furthermore, we investigate the fastest transmission mode among those defined in the C-V2X releases to alert the presence of a pedestrian to the other approaching cars. The proposed technique provides the distances by the crossroad in which is better to use V2V, V2I or V2N according to the environment, the scheduling technique and the measured interference
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