As data rates demands are exploding, 5G will soon rely on mmWaves that offer much higher bandwidths. Yet at these frequencies, attenuation and diffraction of waves require point to point ...communications with beamforming base stations that are complex and power greedy. Furthermore, since any obstacle at these frequencies completely blocks the waves, the networks must be extremely dense, resulting in dramatic increase of its cost. One way to avoid this problem is to redirect beams coming from base stations at many locations with Reconfigurable Intelligent Surfaces, in order to increase their coverage even in cluttered environments. Here we describe and experimentally demonstrate a binary tunable metasurface operating at 28 GHz, based on standard PCB and off the shelves PIN diodes. We show that it can be used as a Reconfigurable Intelligent Surface that beamforms an incoming plane wave at a given angle to one or several outgoing plane waves at angles reconfigurable in real time. Most importantly we use this 20 cm × 20 cm reconfigurable Intelligent Surface alongside software defined radio and up/down converters at 28 GHz, and demonstrate a wireless link between an emitter and a receiver 10 m away, in a non-line-of-sight configuration, hence proving the validity of the approach.
Radio interference in the uplink makes communication to satellites in the UHF amateur radio band (430–440 MHz) challenging for any satellite application. Interference measurements and ...characterisation can improve the robustness and reliability of the communication system design. Most published results focus on average power spectrum measurements and heatmaps. We apply a low complexity estimator on an SDR (Software-Defined Radio) to study the interference’s dispersion and temporal variation on-board a small satellite as an alternative. Measuring the Local Mean Envelope (LME) variability with different averaging window lengths enables the estimation of time variability of the interference. The coefficient of variation for the LME indicates how much the signals vary in time and the spread in magnitudes. In this article, theoretical analysis, simulations, and laboratory results were used to validate this measurement method. In-orbit measurements were performed on-board the LUME-1 satellite. Band-limited interference with pulsed temporal behaviour and a high coefficient of variation was detected over North America, Europe, and the Arctic, where space-tracking radars are located. Wide-band pulsed interference with high time variability was also detected over Europe. These measurements show why operators that use a communication system designed for Additive White Gaussian Noise (AWGN) at power levels obtained from heatmaps struggle to command their satellites.
This book gives a thorough knowledge of cognitive radio concepts, principles, standards, spectrum policy issues and product implementation details. In addition to 16 chapters covering all the basics ...of cognitive radio, this new edition has eight brand-new chapters covering cognitive radio in multiple antenna systems, policy language and policy engine, spectrum sensing, rendezvous techniques, spectrum consumption models, protocols for adaptation, cognitive networking, and information on the latest standards, making it an indispensable resource for the RF and wireless engineer.
This book provides a practical approach to quickly learning the software-defined radio (SDR) concepts needed, and explains how to create wireless design prototypes using SDR for real-world testing ...and experimentation. It also discusses advanced wireless communication techniques such as OFDM, LTE, WLA, and hardware targeting.
By prototyping and evaluating actual digital communication systems capable of performing "over-the-air" wireless data transmission and reception, this volume helps readers attain a first-hand ...understanding of critical design trade-offs and issues. It helps professionals gain a sense of the actual "real-world" operational behavior of these systems.
One of the most critical resources required for wireless communication is the radio spectrum. Traditionally, the administration of the spectrum rights tends to grant exclusive rights to some services ...in the major geographic regions. On the other hand, several studies have shown that the spectrum is actually underutilized and that new devices should use the underutilized spectrum in an opportunistic manner. Cognitive radio is a way to do that. The cognitive radio needs to collect cognition about the radio environment to operate efficiently. Such a radio needs to understand if the spectrum it intends to use is free or utilized by some primary user. By primary user we mean the licensed user of the band, and correspondingly the cognitive radios are often termed as secondary users. The goal of this book is to collect recent research about cognitive radio and provide an up-to-date review of the challenging topic.
This article presents the implementation of an open-source 5G Non-standalone (NSA) network for the Communications Laboratory of the Faculty of Informatics and Electronics. The open-source software ...Open Air Interface (OAI) and USRP B210 devices were used as software defined radio hardware. The network implementation was carried out using Linux containers for the Evolved Packet Core (EPC) and Radio Access Network (RAN) components of OAI. Employing appropriate parameters configurations, a USIM card was programming to ensure the connection of the User Equipment (UE) to the 5G NSA network. Additionally, indoor measurements of the 5G NSA network were conducted using a Samsung Galaxy A52s 5G, to determine the coverage within the FIE Communications Laboratory. In other hand, latency tests revealed delays of 12 ms approximately, and the UE was provided with internet access with UL speeds of 7 Mbps and DL speeds of 125 Mbps approximately. By comparing these results with the theoretical values defined by 3GPP, favourable outcomes were obtained.
Unmanned traffic management (UTM) is a critical component in the integration of unmanned aircraft systems (UAS) into the national airspace. As UAS operations continue to grow in scale and complexity, ...the development of a robust UTM ecosystem becomes essential to ensure the safety and security of the airspace. This survey aims to explore the current state of UTM technology, policies, and procedures, as well as the challenges and opportunities facing the UTM ecosystem. It will review the existing UTM architectures and frameworks, such as those developed by the Federal Aviation Administration (FAA) and the European Union's U-space initiative (U-SPACE), and evaluate their effectiveness in managing UAS operations. Furthermore, it will also examine the key UTM service providers and their offerings, including UAS traffic management systems (UTM systems), communication and navigation systems, and airspace management services. Additionally, it will explore the role of government agencies, UAS operators, and technology providers in the development and implementation of UTM solutions. At last, the author of this paper discuss V2X communication threats related to UTM. By providing a comprehensive overview of the current state of UTM, this study will contribute to a better understanding of the challenges and opportunities in the UTM ecosystem and inform the development of future UTM solutions.
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