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César Briso-Rodríguez - IEEE Xplore Author Profile

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For unmanned aerial vehicle (UAV)-assisted integrated sensing and communication (ISAC) systems, a semantic-based channel state information (CSI) feedback scheme is proposed in this paper. Unlike traditional full CSI feedback, the proposed scheme minimizes feedback burden by utilizing predefined semantic databases at both the transmitter and receiver. Firstly, a deep learning-based clustering metho...Show More
A realistic channel model is vital for designing, optimizing, and evaluating unmanned aerial vehicle (UAV)-to-ground (U2G) communication systems. This paper proposes a shadow fading (SF) model for the U2G channel, which mainly considers the carrier frequency and the distribution of buildings in the scenario. A parametric lognormal model statistically describes the proposed model and the scenario-d...Show More
Long-range wide-area network (LoRaWAN) is a widely used technology in the Internet of Things (IoT), which provides long-range (LoRa) communication with low power consumption. In LoRaWAN, an accurate path loss (PL) model is essential to realize link budget and network coverage planning. In this article, we present an artificial intelligence (AI)-enhanced generalizable scheme for PL prediction in Lo...Show More
With the deep integration between the unmanned aerial vehicle (UAV) and wireless communication, UAV-based air-to-ground (AG) propagation channels need more detailed descriptions and accurate models. In this paper, we aim to conduct cluster-based characterization and modeling for AG channels. To our best knowledge, this is the first study that concentrates on the clustering and tracking of multipat...Show More
High-speed trains are one of the most relevant scenarios for the fifth-generation (5G) mobile communications and the "smart rail mobility" vision, where a high-data-rate wireless connectivity with up to several GHz bandwidths will be required. This is a strong motivation for the exploration of millimeter wave (mmWave) band. In this article, we identify the main challenges and make progress towards...Show More
Metro is important public transportation in reducing traffic congestion, protecting the environment, and moving more people efficiently. Due to ever-increasing demands on high data rate, and seamless connections of the onboard passengers, millimeter-wave (mmWave) wideband communications are considered as potential options. Therefore, realistic mmWave channel characterization, and modeling are impo...Show More
Air-to-ground (AG) communications have attracted much attention for future advanced wireless communications. Unmanned aerial vehicle, as a critical enabler in AG communications, can be operated in various environments, such as over-water, hilly, and built-up environments. A better understanding of radio channels in various scenarios can immensely facilitate the deployment and design of wireless sy...Show More
Unmanned aerial vehicles (UAVs) have aroused great attention for future wireless communications since the drone can be used as an aerial base station and also as a cellular user to perform on-demand tasks. Because the reliable and robust connection between UAV and ground station (GS) plays an essential role in the UAV-based air-to-ground (AG) communications, the accurate radio channel model is nee...Show More
Millimeter-wave (mmWave) wideband communication is considered as a potential candidate to meet the increasing data rate demands of the onboard passengers in the metro. Channel modeling is important for the system design and evaluation in such environment. Ray-tracing (RT) modeling can accurately trace propagation paths, and has been proven successful in many works. However, it is complicated and t...Show More
In order to implement unmanned aerial vehicle (UAV)-based wireless communications, a better understanding of wireless channels and the corresponding channel characterizations are critical. In this paper, air-to-ground (AG) channel measurements are carried out at some candidate frequencies, i.e., 1 GHz, 4 GHz, 12 GHz, and 24 GHz. With measurement data, the crucial channel parameters are comprehensi...Show More
Accurate received power prediction is important to wireless network planning and optimization, and appropriate channel modeling approach is highly demanded. The existing channel modeling approaches mainly include deterministic models and stochastic models. The deterministic models usually require detailed three-dimensional (3D) environment model including geometry and material information. The sto...Show More
Powered by the Internet of Things (IoT), the cellular, vehicular, and other emerging networks, such as space-air-ground integrated networks, are expected to comprehensively evolve into the new era of the Internet of Everything (IoE) in which the propagation links between the IoT devices or sensors become diversified. Thus, a general propagation channel model is required. The line-of-sight (LOS) pr...Show More
Wireless communication has been a fundamental part of railway operation, control, and service systems for decades. In the era of 5G and beyond, the railway communication system is evolving from critical signaling to support various functions to improve the convenience, efficiency, and safety of railway services. Millimeter-wave (mmWave) bands and related technologies are the keys to this vision. T...Show More
In the design of unmanned aerial vehicle (UAV) wireless communications, a better understanding of propagation characteristics and an accurate channel model are required. Measurements and comprehensive analysis for the UAV-based air-ground (AG) propagation channel in the vertical dimension are presented in this letter. Based on the measurement data at 1 and 4 GHz, the large-scale and small-scale ch...Show More
Wireless communication systems are one of the greatest revolutions of our time. In this context, there are still many challenges to be addressed in the field of intelligent transport systems. These are related to the solution of the great difficulties that these complex environments of propagation present such the mobility aspect. In this sense, the objective of this paper is to present a network ...Show More
The maximum altitude of flight for medium and small size UAVs is limited to a maximum height of 120m. Therefore these vehicles frequently fly close to the rooftop of buildings in urban or semi-urban environments, while the control station is 1-2km away. On this conditions, the low flying height moderately affects the propagation by introducing additional losses by diffraction. In this paper we pre...Show More
Train-to-train (T2T) communications can improve the capacity and safety of railways. However, to implement these systems, it is necessary to model the propagation in the complex railway environment, where tunnels and stations are very frequent. This letter presents a detailed modeling of path loss for T2T communications, based on a measurement campaign conducted in a Madrid subway in a tunnel scen...Show More
This paper presents a full characterization of the communications channel inside a train vehicle, in both narrow and wideband configurations. The purpose of this characterization is to be one of the first steps to check the feasibility of a wireless implementation of a train-control management system, a service which has been always carried over a wired network. Many different train topologies and...Show More
High-speed railways (HSRs) improve the quality of rail services, yield greater customer satisfaction, and help to create socioeconomically balanced societies [1]. This highly efficient transport mode creates significant challenges in terms of investment, technology, industry, and environment. To handle increasing traffic, ensure passenger safety, and provide real-time multimedia information, a new...Show More
Due to the extra loss resulting from tunnel curve, most of the theoretical models cannot be directly used for propagation inside curved tunnels. In this paper,extensive simulations are made for propagation at different frequencies in different types of curved tunnels, by using a ray-tracing simulator that is validated by numerous measurements. From the simulated received power, the extra losses of...Show More
Railway and telecommunication companies have showed a great interest in deploying broadband mobile wireless networks in high-speed trains with the aim of supporting both provisioning of passenger services and automatic train control and signaling. This motivates the study of broadband wireless communications between a base-station transmitter and a mobile receiver whose antennas are placed on the ...Show More
Wave propagation experiences extra loss in curved tunnels, which is highly desired for network planning. Extensive narrow-band propagation measurements are made in two types of Madrid subway tunnels (different cross sections and curvatures) with various configurations (different frequencies and polarizations). A ray tracer validated by the straight and curved parts of the measuring tunnels is empl...Show More
The fast development of high speed railway (HSR) promotes the evolution process of wireless communication system. An accurate time delay line (TDL) channel model in HSR environments is thus necessary. In this paper, the correlation property of multi-path components based on empirical measurements at 950 MHz with 33 MHz bandwidth are characterized in real HSR propagation scenario. The results can b...Show More
By summarizing extensive literature, this paper presents a panorama of the path loss exponent and shadow fading distribution in the main rail traffic scenarios. This panorama is very useful to gain a comprehensive understanding of the propagation. Moreover, with the aid of the table provided in this paper, designers can easily realize a fast network planning for a long railway with various scenari...Show More
This paper presents extensive propagation measurements conducted in a modern arched tunnel with 300 m and 500 m radii of curvature with horizontal polarizations at 920 MHz, 2400 MHz, and 5705 MHz, respectively. Based on the measurements, statistical metrics of propagation loss and shadow fading in all the measurement cases are extracted. Furthermore, for each of the large-scale fading parameters, ...Show More