Search

Terahertz (THz) band communications is envisioned as a key technology for future wireless standards. Substantial progress has been made in this field, with advances in hardware design, channel models, and signal processing. High-rate backhaul links operating at sub-THz frequencies have been experimentally demonstrated. However, there are inherent challenges in making the next great leap for adopting the THz band in widespread communication systems, such as cellular access and wireless local area networks. Primarily, such systems have to be both: (i) wideband, to maintain desired data rate and sensing resolution; and, more importantly, (ii) operate in the massive near field of the high-gain devices required to overcome the propagation losses. In this article, it is first explained why the state-of-the-art techniques from lower frequencies, including millimeter-wave, cannot be simply repurposed to realize THz band communication systems. Then, a vision of wavefront engineering is presented to address these shortfalls. Further, it is illustrated how novel implementations of specific wavefronts, such as Bessel beams and Airy beams, offer attractive advantages in creating THz links over state-of-the-art far-field beamforming and near-field beamfocusing techniques. The paper ends by discussing novel problems and challenges in this new and exciting research area. Index Terms - Terahertz Communications; 6G; Wavefront Engineering; Bessel beams; Near field; Orbital Angular Momentum, Accepted to IEEE Wireless Communications Magazine, 2023. \c{opyright}2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material, creating new works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works

One of the important questions when discussing next-generation near-Earth mmWave and terahertz (THz) band satellite communications as an integral part of the 5G-Advanced and 6G landscape is the potential interference-related issues when deploying such systems. While the space-to-ground and ground-to-space interference has been explored in multiple works already, the interference at mmWave and THz cross-links, the links between the satellites themselves, have not been extensively studied yet. However, severe cross-link interference may both challenge the reliability of the data exchange within the constellation, as well as compromise the efficient co-existence of multiple satellite constellations (i.e., by different providers) covering the same or neighboring areas. In this paper, both relevant mathematical models and extensive simulation studies are presented for cross-link mmWave and THz satellite communications. Our results indicate that the cross-link interference in the considered setups is a non-negligible factor that must be further explored and accounted for in the design and deployment of next-general mmWave and THz satellite communication systems., Comment: 7 pages, 7 figures, accepted to IEEE International Conference on Communications, 2023. The copyright may be transferred without further notice after which this version may not be longer available

Communications in the terahertz band (THz) (0.1--10~THz) have been regarded as a promising technology for future 6G and beyond wireless systems, to overcome the challenges of evergrowing wireless data traffic and crowded spectrum. As the frequency increases from the microwave band to the THz band, new spectrum features pose unprecedented challenges to wireless communication system design. The molecular absorption effect is one of the new THz spectrum properties, which enlarges the path loss and noise at specific frequencies. This brings in a double-edged sword for THz wireless communication systems. On one hand, from the data rate viewpoint, molecular absorption is detrimental, since it mitigates the received signal power and degrades the channel capacity. On the other hand, it is worth noticing that for wireless security and covertness, the molecular absorption effect can be utilized to safeguard THz communications among users. In this paper, the features of the molecular absorption effect and their impact on the THz system design are analyzed under various scenarios, with the ultimate goal of providing guidelines to how better exploit this unique THz phenomenon. Specifically, since the molecular absorption greatly depends on the propagation medium, different communication scenarios consisting of various media are discussed, including terrestrial, air and space, sea surface and nano-scale communications. Furthermore, two novel molecular absorption enlightened secure and covert communication schemes are presented, where the molecular absorption effect is utilized as the key and unique feature to boost security and covertness.

[...] This paper explores how spectrum policy and spectrum technologies can evolve to enable sharing among different stakeholders in the above 100 GHz spectrum, without introducing harmful interference or disrupting either security applications or fundamental science exploration. This portion of the spectrum presents new opportunities to design spectrum sharing schemes, based on novel antenna designs, directional ultra-high-rate communications, and active/passive user coordination. The paper provides a tutorial on current regulations above 100 GHz, and highlights how sharing is central to allowing each stakeholder to make the most out of this spectrum. It then defines - through detailed simulations based on standard International Telecommunications Union (ITU) channel and antenna models - scenarios in which active users may introduce harmful interference to passive sensing. Based on this evaluation, it reviews a number of promising techniques that can enable active/passive sharing above 100 GHz. The critical review and tutorial on policy and technologies of this paper have the potential to kickstart future research and regulations that promote safe coexistence between active and passive users above 100 GHz, further benefiting the development of digital technologies and scientific exploration., 26 pages, 17 figures, 5 tables. This paper has been accepted for publication in the Proceedings of the IEEE. Please cite it as M. Polese, X. Cantos-Roman, A. Singh, M. J. Marcus, T. J. Maccarone, T. Melodia, J. M. Jornet, "Coexistence and Spectrum Sharing Above 100 GHz", in Proceedings of the IEEE, 2023, DOI 10.1109/JPROC.2023.3286172

RESUMEN El objetivo de este artículo es exponer el abordaje terapéutico y la importancia del factor humano en la aparición de eventos adversos en lesiones producidas por quemaduras. Para ello presentamos el caso de una mujer de 48 años que sufrió quemaduras dérmicas profundas por exposición a aceite hirviendo en ambas extremidades inferiores con una superficie corporal total quemada del 10%. En atención primaria se estableció un plan de actuación de enfermería con visión holística para evitar la aparición de eventos adversos. Los resultados muestran que, pese a las instrucciones dadas sobre la importancia del reposo, el factor humano de la paciente impidió, a partir de los 15 días, que guardase el reposo necesario. Este hecho produjo la profundización de algunas de las lesiones. Se puede concluir que la aparición de los eventos adversos debidos al factor humano retrasó la curación de las heridas y profundizó las lesiones en ambas extremidades.

Climate change resulting from the misuse and over-exploitation of natural resources has affected and continues to impact the planet's ecosystem. This pressing issue is leading to the development of novel technologies to sense and measure damaging gas emissions. In parallel, the accelerating evolution of wireless communication networks is resulting in wider deployment of mobile telecommunication infrastructure. With 5G technologies already being commercially deployed, the research community is starting research into new technologies for 6G. One of the visions for 6G is the use of the terahertz (THz) spectrum. In this paper, we propose and explore the use of THz spectrum simultaneously for ultrabroadband communication and atmospheric sensing by leveraging the absorption of THz signals. Through the use of machine learning, we present preliminary results on how we can analyze signal path loss and power spectral density to infer the concentration of different climate-impacting gases. Our vision is to demonstrate how 6G infrastructure can provide sensor data for climate change sensing, in addition to its primary purpose of wireless communication., Comment: 7 pages, 5 figures and 1 table

In many places all over the world rural and remote areas lack proper connectivity that has led to increasing digital divide. These areas might have low population density, low incomes, etc., making them less attractive places to invest and operate connectivity networks. 6G could be the first mobile radio generation truly aiming to close the digital divide. However, in order to do so, special requirements and challenges have to be considered since the beginning of the design process. The aim of this white paper is to discuss requirements and challenges and point out related, identified research topics that have to be solved in 6G. This white paper first provides a generic discussion, shows some facts and discusses targets set in international bodies related to rural and remote connectivity and digital divide. Then the paper digs into technical details, i.e., into a solutions space. Each technical section ends with a discussion and then highlights identified 6G challenges and research ideas as a list., A 6G white paper, 17 pages

With the huge advancement of nanotechnology over the past years, the devices are shrinking into micro-scale, even nano-scale. Additionally, the Internet of nano-things (IoNTs) are generally regarded as the ultimate formation of the current sensor networks and the development of nanonetworks would be of great help to its fulfilment, which would be ubiquitous with numerous applications in all domains of life. However, the communication between the devices in such nanonetworks is still an open problem. Body-centric nanonetworks are believed to play an essential role in the practical application of IoNTs. BCNNs are also considered as domain specific like wireless sensor networks and always deployed on purpose to support a particular application. In these networks, electromagnetic and molecular communications are widely considered as two main promising paradigms and both follow their own development process. In this survey, the recent developments of these two paradigms are first illustrated in the aspects of applications, network structures, modulation techniques, coding techniques and security to then investigate the potential of hybrid communication paradigms. Meanwhile, the enabling technologies have been presented to apprehend the state-of-art with the discussion on the possibility of the hybrid technologies. Additionally, the inter-connectivity of electromagnetic and molecular body-centric nanonetworks is discussed. Afterwards, the related security issues of the proposed networks are discussed. Finally, the challenges and open research directions are presented.

RESUMEN: Las quemaduras son lesiones cutáneas causadas por agentes térmicos, químicos, radioactivos o eléctricos, que, en función del tiempo de exposición al agente causal, transmiten el calor a los distintos tejidos. Las quemaduras de tratamiento ambulatorio son heridas con bajo riesgo de infección. La zona corporal quemada nos indicará el potencial de gravedad de la lesión. La encuesta de morbilidad hospitalaria actualizada en 2016 refleja un registro de 75.356 quemaduras. Presentamos el caso clínico de un hombre de 40 años, sano, que presentó quemadura en cara interna del brazo, con zonas dérmicas y sub-dérmicas, un 3% de superficie corporal quemada y afectación de la articulación del codo. Los cuidados de enfermería se desarrollaron en cuatro fases bien diferenciadas para su adecuada epitelización. Concluimos en que algunas opciones terapéuticas muy utilizadas, pueden enlentecer el proceso de cicatrización. En nuestro caso, la cura en ambiente húmedo ha demostrado ser la mejor opción terapéutica. El tratamiento de las quemaduras debe ser integral y prolongado en el tiempo. ABSTRACT: The burns are skin lesions caused by thermal, chemical, radioactive or electrical agents, which, depending on the time of exposure to the causative agent, transmit heat to different tissues. Outpatient treatment burns are wounds with low risk of infection. The burned body area will indicate the serious potential of the injury. The hospital morbidity survey updated in 2016 reflects a record of 75,356 burns. We present the clinical case of a 40-year-old man, healthy, who presented a burn on the inside of his arm, with dermal and sub-dermal areas, a 3% burned body surface area and involvement of the elbow joint. Nursing care was developed in four distinct phases for adequate epithelization. We conclude that some widely used therapeutic options can slow down the healing process. In our case, the Cure in Humid Environment has proven to be the best therapeutic option. The treatment of burns should be comprehensive and prolonged over time.