The concept of cognitive radio (or secondary spectrum access) is currently under investigation as a promising paradigm to achieve efficient use the frequency resource by allowing coexistence licensed (primary) and unlicensed (secondary) users in same bandwidth. According property-rights model radio, primary terminals own given bandwidth may decide lease it for fraction time nodes exchange appropriate remuneration. In this paper, we propose analyze an implementation framework, whereby link...

A scenario with two single-user links, one licensed to use the spectral resource (primary) and unlicensed (secondary or cognitive), is considered. According cognitive radio principle, activity of secondary link required not interfere performance primary. Therefore, in this paper, it assumed that accesses channel only when sensed idle. Moreover, analysis includes: (1) random packet arrivals; (2) sensing errors due fading at link; (3) power allocation transmitter based on long-term...

This article has explored history, recent advances, and challenges in distributed synchronization for wireless systems. It is focused on schemes based exchange of signals at the physical layer corresponding baseband processing, wherein analysis design can be performed using known tools from signal processing. Emphasis also been given synergy between estimation/detection problems. Finally, we have touched upon nonperiodic (chaotic) signals. Overall, hope to conveyed relevance subject provided...

In orthogonal frequency division multiplexing (OFDM) systems over fast-varying fading channels, channel estimation and tracking is generally carried out by transmitting known pilot symbols in given positions of the frequency-time grid. The traditional approach consists two steps. First, least-squares (LS) estimate obtained subcarriers. Then, this preliminary interpolated/smoothed entire paper, we propose to add an intermediate step, whose purpose increase accuracy presented techniques are...

The design of Medium Access Control (MAC) protocols for wireless sensor networks (WSNs) has been conventionally tackled by assuming battery-powered devices and adopting the network lifetime as main performance criterion. While WSNs operated energy-harvesting (EH) are not limited lifetime, they pose new challenges due to uncertain amount energy that can be harvested from environment. Novel criteria thus required capture trade-offs between potentially infinite availability. This paper...

Wireless propagation is conventionally considered as the enabling tool for transporting information in digital communications. However, recent research has shown that perturbations of same electromagnetic (EM) fields are adopted data transmission can be used a powerful sensing device-free radio vision. Applications range from human body motion detection and localization to passive gesture recognition. In line with current evolution mobile phone [1], terminals not only ubiquitous...

Space-time modulated metasurfaces (STMMs) are a newly investigated technology for the next 6G generation wireless communication networks. An STMM augments spatial phase function with time-varying one across meta-atoms, allowing conveyance of information that possibly modulates impinging signal. Hence, represents an evolution reconfigurable intelligent surfaces (RIS), which only design pattern. STMMs convey signals without relevant increase in energy budget, is convenient applications where...

The large number of network nodes and the energy constraints make Wireless Sensor Networks (WSN) one most important application fields for Cooperative Diversity. Node cooperation increases spatial diversity wireless channels and, thus, reduces transmitted power. In this paper, we propose a multi-hop WSN with grouped in cooperative clusters that exploits transmit receive among cluster nodes. Multi-hop transmission is carried out by concatenating single cluster-to-cluster hops, where every...

The phase of complex signals is wrapped since it can only be measured modulo-2/spl pi/; unwrapping searches for the 2/spl pi/-combinations that minimize discontinuity unwrapped phase, as analyzed and interpreted by further processing. Given an estimate gradient (i.e., instantaneous frequency), 2-D obtained a solution variational problem. analysis done quite separately from frequency estimation so reliability both steps assessed independently. Various methods evaluating are presented compared...

This paper deals with the problem of radio localization moving terminals (MTs) for indoor applications mixed line-of-sight/non-line-of-sight (LOS/NLOS) conditions. To reduce false localizations, a grid-based Bayesian approach is proposed to jointly track sequence positions and sight conditions MT. method based on assumption that both MT position condition are Markov chains whose state hidden in received signals [hidden model (HMM)]. The observations used HMM obtained from power-delay profile...

Cooperation is increasingly regarded as a key technology for tackling the challenges of practical implementation cognitive radio. In this paper, we first give brief overview envisioned applications cooperative to radio, distinguishing among sensing detection primary activity, transmission between secondary nodes and traffic by users (cognitive relaying). Then, focus on latter scenario investigate simple wireless network, where one transmitter has option relay primary. Assuming that oblivious...

In wireless sensor networks, distributed timing synchronization based on pulse-coupled oscillators at the physical layer is currently being investigated as an interesting alternative to packet synchronization. this paper, convergence properties of such a system are studied through algebraic graph theory, by modeling nodes discrete-time clocks. A general scenario where clocks may have different free-oscillation frequencies considered, and both time-invariant time-variant network topologies...

Wireless sensor networks (WSN) employ self-powered sensing devices that are mutually interconnected through wireless ad-hoc technologies. This study illustrates the basics of WSN-based traffic monitoring and summarises possible benefits in Intelligent Transport Systems (ITS) applications for improvement quality safety mobility. Compared with conventional infrastructure-based systems, this technology facilitates a denser deployment sensors along road, resulting higher spatial resolution...

Large-scale adoption of dense cloud-based wireless network technologies in industrial plants is mandatorily paired with the development methods and tools for connectivity prediction deployment validation. Layout design procedures must be able to certify quality (or reliability) information flow scenarios characterized by harsh propagation environments. In addition, these account possibly coexisting heterogeneous radio access as part Internet Things (IoT) paradigm, easily allow post-layout...

The evolution of Advanced Driver Assistance Systems (ADAS) towards the ultimate goal autonomous driving relies on a conspicuous number sensors, to perform wide range operations, from parking assistance emergency braking and environment mapping for target recognition/classification. Low-cost Mass-Market Radars (MMRs) are today widely used object detection at various ranges (up 250 meters) but they might not be suited high-precision mapping. In this context, vehicular Synthetic Aperture Radar...

In this paper, we discuss the possibility of generating high-resolution mapping urban (or extra-urban) environments by application synthetic aperture radar (SAR) processing concepts to data collected mm-wave automotive radars installed on-board commercial vehicles. The study is motivated fact that sensors are becoming an indispensable component equipment modern vehicles, being characterized low cost, good performance, and affordable processing; therefore, in future, nearly every single...

Electromagnetic (EM) inversion is a useful tool for quantitative analysis in short-range applications of pulse radars. To estimate multilayered media properties using monostatic radar, two inverse scattering approaches are discussed: (a) layer-stripping algorithm by exploiting amplitude and time delay radar echoes after their detection, (b) EM problem parameter optimization minimizing the mean square error between measured modeled data. Redundancy estimation given spatial continuous...

A novel distributed scheme that combines cooperative ARQ with the spectrum leasing paradigm is proposed and analyzed. The strategy harnesses opportunistic gains of communications, while inherently providing a spectrum-rewarding incentive for otherwise non-cooperative relays to assist source's transmission. As in ARQ, source might decide hand over possible retransmission slots nearby stations were able decode original In scheme, however, exchange cooperation, relaying station also awarded an...

Seismic exploration and monitoring for oil gas reservoirs is a peculiar application that requires large number (1000-2000 nodes/sqkm) of geophone sensors deployed outdoors over areas (≥ 40 sqkm) to measure backscattered wave fields from artificial sources. A storage/processing unit or sink node collects the measurements all geophones obtain an image sub-surface. The existing cabling system connect known cause inefficiencies, logistic weight costs, as well insufficient flexibility in survey...

Recent advances of hardware design and radio technologies have opened the way for an emerging category network-enabled smart physical devices as a result convergence in computing wireless communication capabilities. Inspired by biological interactions, distributed processing data collected individual is now becoming crucial to let nodes self-learn relevant network-state information self-organize without support central unit. Focus this paper twofold. First, novel network channel model...

Millimeter wave (mmWave) wideband channels in a multiple-input multiple-output (MIMO) transmission are described by sparse set of impulse responses the angle-delay, or space-time (ST), domain. These characteristics will be even more prominent THz band used future systems. We consider two approaches for channel estimation: compressed-sensing (CS), exploiting sparsity angular/delay domain, and low-rank (LR), algebraic structure matrix. Both share several commonalities, this paper provides...

This paper presents a web-based software tool for tutoring support of engineering students without any need data scientist background usage. is focused on the analysis students' performance, in terms observable scores and completion their studies. For that purpose, it uses set only contains features typically gathered by university administrations about students, degrees subjects. The provides access to results from different analyses. Clustering visualization low-dimensional representation...

With the advent of self-driving vehicles, autonomous driving systems will have to rely on a vast number heterogeneous sensors perform dynamic perception surrounding environment. Synthetic Aperture Radar (SAR) increase resolution conventional mass-market radars by exploiting vehicle's ego-motion, requiring very accurate knowledge trajectory, usually not compatible with automotive-grade navigation systems. In this setting, radar data are typically used refine navigation-based trajectory...

In future 6G millimeter-wave/sub-THz vehicle-to-everything communication systems, vehicles are expected to be equipped with massive antenna arrays compensate for the severe path loss. However, vehicle-to-vehicle (V2V) direct links prone blockage by surrounding vehicles. Emerging metasurface technologies enable control of electromagnetic wave reflection towards desired direction boost performance. Reconfigurable intelligent surfaces (RIS), and pre-configured counterpart reflecting (IRS),...