Scintillation due to atmospheric turbulence is one of the effects challenging the reuse of extremely wideband and high-rate optical satellite-to-satellite communication systems for satellite-to-Earth and Earth-to-satellite transmissions. In this article, we study the possibility of utilizing links in the terahertz (THz) frequency bands for these uplink and downlink transmissions instead. Built upon the physics-based model, originally developed for optical wave propagation, we present a mathematical framework for the THz signal scintillation to analyze atmospheric turbulence's impact on ground-satellite and airplane-satellite connections. Our results indicate that, while the scintillation still significantly impacts the power of the received THz signal (especially at lower elevation angles and under specific weather conditions), the effect is drastically less profound than the extreme losses the optical link will experience in the same weather conditions. We further explore a notable asymmetry of up to 10 dB between uplink and downlink losses. Finally, we illustrate that, even at relatively low airplane altitudes, the airplane-to-satellite link is much less affected than the Earth-to-satellite link, making THz communications a promising candidate technology for future high-rate airplane connectivity systems as a part of 6G and beyond.

The terahertz (THz) spectrum holds immense potential for advanced wireless communication systems due to abundant available bandwidth and high data rates. However, a major challenge in deploying THz systems is susceptibility to blockage, which can greatly impair signal propagation and negatively affect the reliability of the communication link. This paper focuses on applying self-accelerated beams for blockage mitigation at THz frequencies. These beams can follow curved trajectories as they propagate in free space. Trajectories can be engineered to overcome physical obstacles present in the beam path. As we show through extensive simulations, self-accelerated beams perform better than conventional Gaussian beams in terms of received power when obstacles are present. This approach offers new possibilities for reliable THz communications in practical deployment scenarios.

The extremely short wavelength of terahertz (THz) communications leads to an extended radiative near-field region, in which some canonical far-field assumptions fail. Existing near-field boundary formulations (Fraunhofer distance) for uniform linear/planar array (ULA/UPA) configurations assume ideal alignment between transceivers, overlooking practical misalignments caused by mobility or mechanical imperfections. This paper addresses this critical gap by analyzing the impact of spatial misalignment on near-field distance calculations in THz systems. We derive exact analytical expressions and simplified approximations for the near-field boundary in both ULA–ULA and UPA–UPA configurations under arbitrary misalignment off-sets. Through numerical simulations, we validate our theoretical models and quantify how misalignment reshapes the near-field region. These findings provide essential guidelines for optimizing THz system deployment in realistic scenarios.

For decades, the terahertz (THz) frequency band had been primarily explored in the context of radar, imaging, and spectroscopy, where multi-gigahertz (GHz) and even THz-wide channels and the properties of THz photons offered attractive target accuracy, resolution, and classification capabilities. Meanwhile, the exploitation of the THz band for wireless communication had originally been limited due to several reasons:1) no immediate need for such high data rates available via THz bands and 2) challenges in designing sufficiently high-power THz systems at reasonable cost and efficiency, leading to what was often referred to as “the THz gap.” Over the recent decade, advances on many fronts have drastically changed the THz landscape. First, the evolution from 5G-to 6G-grade wireless systems dictates the need to support novel bandwidth-hungry applications and services for both data transfer i.e., eXtended Reality (XR), the Metaverse, and vast modeling needs of artificial intelligence (AI) and machine learning (ML), as well as centimeter-precision sensing and classification (i.e., for standalone position location, vehicle-to-everything (V2X), or unmanned aerial vehicle (UAV) tracking). Second, substantial progress in THz hardware has been achieved, offering promise that the THz technology gap will be closed. Hence, THz-band wireless communication seems inevitably an essential part of the future networking technology landscape in the coming decades. To design efficient THz systems, the peculiarities of THz hardware and THz channels need to be understood and accounted for. This roadmap paper first reviews the evolution of the hardware design approaches for THz systems, including electronic, photonic, and plasmonic approaches, and the understanding of the THz channel itself, in diverse scenarios, ranging from common indoors and outdoors scenarios to intrabody and outer space environments. This article then summarizes the lessons learned during this multidecade process and the cutting-edge state-of-the-art findings, including novel methods to quantify power efficiency, which will become more important in making design choices. Finally, this article presents the authors’ perspective and insights on how the evolution of THz systems design will continue toward enabling efficient THz communications and sensing solutions as an integral part of next-generation wireless systems.

In this paper, the physical layer security of terahertz (THz) band communications in the near field is discussed and evaluated. First, a novel class of design approaches to enhance the security of near-field THz links is proposed. These approaches are referred to as wavefront hopping schemes, as they exploit the properties of different THz wavefronts when propagating beams in the near field (particularly, THz Bessel beams and THz Airy beams). Then, a compound evaluation framework is delivered to assess both the performance and the security level of a given single-beam or multi-beam solution for a near-field THz system. Finally, a performance evaluation is conducted illustrating the performance/secrecy trade-offs associated with the modeled single-beam and multi-beam security schemes for both a single Attacker and a team of cooperating Attackers. Our results indicate that the proposed multi-beam solutions combining THz Airy beam(s) with THz Bessel beam through wavefront hopping lead to a notably decreased probability of message eavesdropping while maintaining nearly identical performance with the single-beam schemes. The contributed security schemes, evaluation methodology, and numerical results facilitate further development in the emerging area of secure near-field THz communications for 6G and beyond wireless networks.

Terahertz-band (100 GHz-10 THz) communication is a promising radio technology envisioned to enable ultra-high data rate, reliable and low-latency wireless connectivity in next-generation wireless systems. However, the low transmission power of THz transmitters, the need for high gain directional antennas, and the complex interaction of THz radiation with common objects along the propagation path make crucial the understanding of the THz channel. In this paper, we conduct an extensive channel measurement campaign in an indoor setting (i.e., a conference room) through a channel sounder with 0.1 ns time resolution and 20 GHz bandwidth at 140 GHz. Particularly, the impact of different antenna directivities (and, thus, beam widths) on the channel characteristics is extensively studied. The experimentally obtained dataset is processed to develop the path loss model and, subsequently, derive key channel metrics such as the path loss exponent, delay spread, and K-factor. The results highlight the multi-faceted impact of the antenna gain on the channel and, by extension, the wireless system and, thus, show that an antenna-agnostic channel model cannot capture the propagation characteristics of the THz channel.

The increasing demand for ultra-high data rates in wireless communications has attracted interest in upper-frequency bands, namely sub-terahertz and terahertz frequencies. However, severe path loss and narrow beamwidth antennas used at these frequencies necessitate precise antenna alignment and realignment algorithms. Existing solutions often rely on constrained simulations or out-of-band techniques that may not capture the unique propagation characteristics of terahertz frequencies. To address this challenge, we introduce THzAlign, an integrated sub-terahertz and terahertz platform that enables rapid prototyping and real-world testing of antenna alignment algorithms. THzAlign combines rotary tables for precise beam steering with a modular software architecture supporting algorithm simulation and over-the-air experiments. To illustrate this platform, we evaluate three reference realignment algorithms in terms of their performance using THzAlign under varying distances, frequencies, and antenna beamwidth conditions. The developed platform with its documented API facilitates real-world hardware validation of forthcoming advanced solutions for beam (re-)alignment as an integral part of intelligent ultra-high-rate communication systems in the (sub-)THz bands toward 6G and beyond.

Emerging from the symbiotic combination of nanotechnology and communications, the field of nanonetworking has come a long way since its inception more than fifteen years ago. Significant progress has been achieved in several key communication technologies as enablers of the paradigm, as well as in the multiple application areas that it opens. In this paper, the focus is placed on the electromagnetic nanonetworking paradigm, providing an overview of the advances made in wireless nanocommunication technology from microwave through terahertz to optical bands. The characteristics and potential of the compared technologies are then confronted with the requirements and challenges of the broad set of nanonetworking applications in the Internet of NanoThings (IoNT) and on-chip networks paradigms, including quantum computing applications for the first time. Finally, a selection of cross-cutting issues and possible directions for future work are given, aiming to guide researchers and practitioners towards the next generation of electromagnetic nanonetworks.

Nanotechnology is enabling the development of devices on a scale ranging from one to a few hundred nanometers. At this scale, a nanomachine is defined as the most basic functional unit, integrated by nano-components which can carry out sensing and actuation. Coordination and information communication among several nanomachines expand the potential applications of individual devices both in terms of complexity and range of operation. The resulting nanonetworks can cover wide areas, to reach unprecedented locations in a non-invasive way. Moreover, the integration of nanonetworks with classical networks and ultimately with the Internet results in a new networking paradigm, which is referred to as the Internet of Nano-Things (IoNT) by Akyildiz and Jornet one and a half decades ago.

High-rate satellite communications among hundreds and even thousands of satellites deployed at low-Earth orbits (LEO) will be an important element of the forthcoming sixth-generation (6G) of wireless systems beyond 2030. With millimeter wave communications (mmWave, ≈30 GHz–100 GHz) completely integrated into 5G terrestrial networks, exploration of its potential, along with sub-terahertz (sub-THz, 100 GHz–300 GHz), and even THz (300 GHz–3 THz) frequencies, is underway for space-based networks. However, the interference problem between LEO mmWave/THz satellite cross-links in the same or different constellations is undeservedly forgotten. This article presents a comprehensive mathematical framework for modeling directional interference in all key possible scenario geometries. The framework description is followed by an in-depth numerical study on the impact of cross-link interference on various performance indicators, where the delivered analytical results are cross-verified via computer simulations. The study reveals that, while highly directional mmWave and, especially, THz beams minimize interference in many cases, there are numerous practical configurations where the impact of cross-link interference cannot be neglected and must be accounted for.

Near-field mobile terahertz (THz) communications is one of the candidate enablers for high-rate wireless data exchange in sixth-generation (6G) networks. However, operating in the THz near field brings both attractive opportunities and severe challenges. Hence, it becomes of interest to explore if it is possible to design a realistic mobile THz communication system without working in the THz near field. To answer this question, a mathematical framework is presented modeling a mobile THz link that works exclusively in the far field. The study leads to an interesting theoretical conclusion: while the actual frequency is of (almost) no interest, such a system must operate over a limited bandwidth not exceeding a certain threshold. It is then numerically shown that operating only in the far field imposes stringent limitations on mobile THz communications, thus making them less attractive to prospective high-rate services. In contrast, it is shown that a stationary THz link can still be broadband even when staying exclusively in the THz far field. Hence, broadband mobile THz communications MUST be near-field, while broadband stationary THz links do not have to.

Exploring near-field propagation is increasingly relevant for terahertz(THz)-band communications, as very large antenna arrays (VLAA) are required to overcome the large propagation losses. In the near field, the efficiency of conventional far-field beamforming is reduced, while state-of-the-art near-field beamfocusing requires perfect positioning and channel state information to work efficiently. In this paper, first, experimental measurements of wireless data transmission above 100 GHz in indoor scenarios are presented to highlight the need for VLAAs that will likely operate in the near field. Next, diffraction-free Bessel beams are described as a promising near-field contender, with propagation characteristics in the near field similar to those of beamforming in the far field. Numerical results and their interpretations highlight the impact of prospective wideband THz communications during system implementations. It is particularly observed that THz Bessel beams can be optimized for the given environment, potentially improving the performance characteristics of the system.

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.

Wireless communications in the low terahertz band (0.1 THz-1 THz) is a promising candidate to enable ultra-high-rate vehicular networks beyond 5G. The successful design and adoption of such systems require a deep understanding of the low THz channel specifics in complex vehicular scenarios. In this paper, a comprehensive measurement campaign is reported with the aim of analyzing the wave propagation at 300 GHz in typical vehicular deployments. Following a modular approach, the generic vehicular scenario is decomposed into basic propagation setups that are further analyzed in detail. The obtained measurement data are then applied to derive the mathematical approximations that characterize the low THz band channel properties for each scenario. Finally, the combination of measurement and modeling results is used to identify the critical propagation effects that has to be accounted for in the applied studies. The presented approach, raw and processed data, as well as the contributed analysis, serve as building blocks for future analytical and simulation tools to model prospective vehicular communication systems in the low THz band.

The capability of smarter networked devices to dynamically select appropriate radio connectivity options is especially important in the emerging millimeter-wave (mmWave) systems to mitigate abrupt link blockage in complex environments. To enrich the levels of diversity, mobile mmWave relays can be employed for improved connection reliability. These are considered by 3GPP for on-demand densification on top of the static mmWave infrastructure. However, performance dynamics of mobile mmWave relaying is not nearly well explored, especially in realistic conditions, such as urban vehicular scenarios. In this paper, we develop a mathematical framework for the performance evaluation of mmWave vehicular relaying in a typical street deployment. We analyze and compare alternative connectivity strategies by quantifying the performance gains made available to smart devices in the presence of mmWave relays. We identify situations where the use of mmWave vehicular relaying is particularly beneficial. Our methodology and results can support further standardization and deployment of mmWave relaying in more intelligent 5G+ "all-mmWave" cellular networks.

The landscape of the contemporary IoT radio access technologies (RATs) is excessively diverse, especially when it comes to such a complex environment as Smart City. On the one hand, this diversity offers operators sufficient flexibility to select the most appropriate RAT for their target application. On the other hand, it becomes a severe limiting factor leading to high level of uncertainty for the IoT device vendors, who need to decide, which technology to support in their hardware. In this paper, we consider the provisioning of the low-power wide area network (LPWAN) devices supporting multiple RATs. First, we briefly discuss the parameters of several potential radio technologies as well as analyze the pros and cons of combining them in a single device. Next, we prototype a real-life device capable of communicating via two perspective LPWAN technologies, namely, LoRaWAN and NB-IoT, and report on the initial results of its performance evaluation. These confirm the feasibility of instrumenting dual-mode devices as well as reveal several important aspects related to the development of multi-radio IoT equipment and its performance. In our view, due to their higher flexibility, reliability, and dependability, the devices such as the one developed can be beneficial for various Smart City applications, with smart energy grids and road traffic control being only two of many examples.

Dense deployments of millimeter-wave (mmWave) base stations (BSs) are being considered as the most feasible solution to meet the steadily growing data rate demands of mobile users. Accordingly, the achievable performance gains of mmWave-based dense networks in real deployments have to be studied carefully, since mmWave radio technology features specific transceiver, antenna, and propagation properties. In this paper, we contribute an accurate performance evaluation of single- versus dual-polarized MIMO systems operating over the mmWave channel in typical urban scenarios as well as address the impact of device- and network-centric parameters on the performance gains enabled by MIMO in dense to ultra-dense BS deployments. This study relies on our in-house ray-based modeler and takes into account the key mmWave system effects, such as multi-path propagation, utilization of dual-polarized antennas, and characteristic interference models. Our results show that the benefit of using mmWave- MIMO grows with increasing BS density, thus encouraging a further study of this technology especially for (ultra-)dense setups. We also demonstrate that non-coherent non-polarized diffuse scattering component may reduce the capacity gain of dual-polarized vs. single- polarized MIMO.

The Internet of Things (IoT) undergoes a fundamental transformation by augmenting its conventional sensor network deployments with more advanced and mobile devices, such as connected and self-driving cars. This fusion of embedded and automotive domains promises to deliver unprecedented mutual benefits, where vehicles will receive timely updates from their proximate sensors while assisting them in delivering their sensory data to the remote network infrastructure. In this paper, we put forward the vision of opportunistic crowdsensing applications, in which the ubiquitous deployments of low-cost and battery-constrained IoT sensors take advantage of more capable and energy-abundant vehicle-mounted mobile relays. In particular, we consider the use of the emerging narrowband IoT radio technology recently ratified by 3GPP and offering efficient means for underlying wireless connectivity. Our rigorous mathematical analysis supported with comprehensive system-level evaluations reveals the effects of vehicle-based relays on the important metrics of interest, such as connection reliability, transmission latency, and communication energy efficiency. These systematic findings advocate for an extensive utilization of vehicular relays as part of the next-generation IoT ecosystem.

To satisfy the stringent capacity and scalability requirements in the fifth generation (5G) mobile networks, both wireless access and backhaul links are envisioned to exploit millimeter wave (mmWave) spectrum. Here, similar to the design of access links, mmWave backhaul connections must also address many challenges such as multipath propagation and dynamic link blockage, which calls for advanced solutions to improve their reliability. To address these challenges, 3GPP New Radio technology is considering a flexible and reconfigurable backhaul architecture, which includes dynamic link rerouting to alternative paths. In this paper, we investigate the use of aerial relay nodes carried by e.g., unmanned aerial vehicles (UAVs) to allow for such dynamic routing, while mitigating the impact of occlusions on the terrestrial links. This novel concept requires an understanding of mmWave backhaul dynamics that accounts for: 1) realistic 3-D multipath mmWave propagation; 2) dynamic blockage of mmWave backhaul links; and 3) heterogeneous mobility of blockers and UAV-based assisting relays. We contribute the required mathematical framework that captures these phenomena to analyze the mmWave backhaul operation in characteristic urban environments. We also utilize this framework for a new assessment of mmWave backhaul performance by studying its spatial and temporal characteristics. We finally quantify the benefits of utilizing UAV assistance for more reliable mmWave backhaul. The numerical results are confirmed with 3GPP-calibrated simulations, while the framework itself can aid in the design of robust UAV-assisted backhaul infrastructures in future 5G mmWave cellular.

Network softwarization is a major paradigm shift, which enables programmable and flexible system operation in challenging use cases. In the fifth-generation (5G) mobile networks, the more advanced scenarios envision transfer of high-rate mission-critical traffic. Achieving end-to-end reliability of these stringent sessions requires support from multiple radio access technologies and calls for dynamic orchestration of resources across both radio access and core network segments. Emerging 5G systems can already offer network slicing, multi-connectivity, and end-to-end quality provisioning mechanisms for critical data transfers within a single software-controlled network. Whereas these individual enablers are already in active development, a holistic perspective on how to construct a unified, service-ready system as well as understand the implications of critical traffic on serving other user sessions is not yet available. Against this background, this paper first introduces a softwarized 5G architecture for end-to-end reliability of the mission-critical traffic. Then, a mathematical framework is contributed to model the process of critical session transfers in a softwarized 5G access network, and the corresponding impact on other user sessions is quantified. Finally, a prototype hardware implementation is completed to investigate the practical effects of supporting mission-critical data in a softwarized 5G core network, as well as substantiate the key system design choices.

Leveraging multiple simultaneous small cell connections is an emerging and promising solution to enhance session continuity in millimeter-wave (mmWave) cellular systems that suffer from frequent link interruptions due to blockage in ultra-dense urban deployments. However, the available performance benefits of feasible multi-connectivity strategies as well as the tentative service quality gains that they promise remain an open research question. Addressing it requires the development of a novel performance evaluation methodology, which should consider: 1) the intricacies of mmWave radio propagation in realistic urban environments; 2) the dynamic mmWave link blockage due to human mobility; and 3) the multi-connectivity network behavior to preserve session continuity. In this paper, we construct this much needed methodology by combining the methods from queuing theory, stochastic geometry, as well as ray-based and system-level simulations. With this integrated framework, both user- and network-centric performance indicators together with their underlying scaling laws can be quantified in representative mmWave scenarios. To ensure modeling accuracy, the components of our methodology are carefully cross verified and calibrated against the current considerations in the standards. Building on this, a thorough comparison of alternative multi-connectivity strategies is conducted, as this paper reveals that even simpler multi-connectivity schemes bring notable improvements to session-level mmWave operation in realistic environments. These findings may become an important reference point for subsequent standardization in this area.

The fifth generation wireless systems are expected to rely on a large number of small cells to massively offload traffic from the cellular and even from the wireless local area networks. To enable this functionality, mm-wave (EHF) and Terahertz (THF) bands are being actively explored. These bands are characterized by unique propagation properties compared with microwave systems. As a result, the interference structure in these systems could be principally different to what we observed so far at lower frequencies. In this paper, using the tools of stochastic geometry, we study the systems operating in the EHF/THF bands by explicitly capturing three phenomena inherent for these frequencies: (1) high directivity of the transmit and receive antennas;( 2) molecular absorption; and (3) blocking of high-frequency radiation. We also define and compare two different antenna radiation pattern models. The metrics of interest are the mean interference and the signal-to-interference-plus-noise (SINR) ratio at the receiver. Our results reveal that: (1) for the same total emitted energy by a Poisson field of interferers, both the interference and SINR significantly increase when simultaneously both transmit and receive antennas are directive and (2) blocking has a profound impact on the interference and SINR creating much more favorable conditions for communications compared with no blocking case.

The fifth generation wireless systems are expected to rely on a large number of wideband small cells to offload traffic from the cellular and wireless local area networks. To create such small cells, EHF and THF bands are actively explored. These frequencies are characterized by fundamentally different propagation characteristics resulting in different interference structure at the receiver compared to, e.g., microwave systems. In this paper, we study the interference structure for systems operating in EHF/THF bands by explicitly capturing three major phenomena: (i) extreme directivity of the transmit and/or receive antennas, (ii) pass loss component caused by molecular absorption and (iii) blocking of high-frequency radiation. The metric of interest is the mean interference at the receiver. Our results reveal that (i) for the same emitted energy in a Poisson field of interferers, the interference increases with the directivity of the transmit or receive antennas, (ii) blocking has a profound impact on the interference creating much more favorable conditions for communications compared to lower frequencies and (iii) the choice of the antenna model is of crucial importance for accurate performance assessment.

To efficiently utilize ultra-short range wireless technologies providing extreme data rates at the air interface, the concept of “information shower” (IS) has been proposed to complement typical small cell deployments. Although the concept was introduced several years ago, the benefits of ISs is still an open question. We propose an analytical framework for performance evaluation of ISs operating in the terahertz (THz) frequency band. Taking into account different THz bandwidth allocations resulting in different IS coverages and capacities and assuming applications capable of data prefetching, we estimate both user- and network-centric metrics as a function of input parameters including mobility of users. Our study reveals that initiating heavy traffic sessions upon entering THz ISs allows to offload up to 95% of traffic from long-range networks even for low IS sizes and high user densities as the THz IS data rates efficiently compensates for large inter-IS visit times. Such massive offloading also results in considerable improvements in mobile terminal energy efficiency as the fraction of time the radio interfaces have to be active drastically decreases.

Utilizing bacteria as information carriers is a promising technique for molecular communication to establish connections and networking capabilities between micro- and nanoscale devices. A particular process, that is of interest in this paper, and vital to achieve reliable networking performance in bacterial nanonetwork, is conjugation. Conjugation is a process where bacteria come within close range to form physical connections to allow plasmids to be transferred. However, there are a number of processes that could cause loss or damage during the transfer process, such as external vibrations. Message encoding techniques are envisioned as a promising technique to mitigate these effects. In this study we first define the concept of optimal message encoding for bacterial nanonetworks providing the upper bound on the message delivery time and the probability of message delivery within the specified time. We then investigate the effect of encoding on the performance of these metrics by proposing and numerically comparing several feasible encoding techniques. The performance comparison has been done using a specifically developed simulation environment capturing bacteria movement and interactions. Numerical results demonstrate that even the simple encoding strategies allow to significantly improve the performance compared to the baseline system.

Wireless communications in the terahertz (THz) frequency band, 0.1-10THz, promises a rapid increase of channel capacity in next- generation networks. However, the advantages of this technology depend not only on the single link performance, but also on the possibility of several THz links to coexist in the same area. Thus, the efficiency of spatial channel reuse has to be studied. Due to the presence of specific effects in the THz band, such as molecular absorption and molecular noise, existing performance evaluation techniques are not straightforwardly applicable. In this paper, the approach for network-level analysis of THz wireless communications is proposed. This approach is based on the tools of stochastic geometry and takes into account the specific signal propagation features of the THz frequency band. The presented technique is used to derive the distribution of SINR and spectral efficiency as well as to estimate the optimal distance between receiving nodes and maximize the area capacity.

Over the last decade short-range communications in the terahertz band have been extensively studied as a technology-enabler for dense and ultra-dense wireless networks. Recent advances in miniaturized terahertz transceivers design promise wireless connectivity and simultaneous interaction between thousands of devices. However, the feasibility of network-wide communications is still an open issue due to specific features of the terahertz band and inherent properties of dense deployments. We address this issue developing an analytical model for interference and SINR assessment in dense terahertz networks obtaining the first two moments and density functions for both metrics. Our results demonstrate that the presence of molecular noise does not qualitatively affect the behavior of SINR, while its quantitative effect is of secondary importance compared to interference. The presented approach provides the so-far missing building block for performance analysis of prospective dense terahertz networks.

In this paper, we address the emerging concept of Machine-Type Communications (MTC), where unattended wireless devices send their data over the Long Term Evolution (LTE) cellular network. In particular, we emphasize that future MTC deployments are expected to feature a very large number of devices, whereas the data from a particular device may be infrequent and small. Currently, LTE is not optimized for such traffic and its data transmission schemes are not MTC-specific. To improve the efficiency of small data access, we propose a novel contention-based LTE transmission (COBALT) mechanism and evaluate its performance with both analysis and protocol-level simulations. When compared against existing alternatives, our data access scheme is demonstrated to improve network resource consumption, device energy efficiency, and mean data access delay. We conclude that COBALT has the potential for supporting massive MTC deployments based on the future releases of the LTE technology.

In this paper the lightweight many-to-many authentication protocol, that uses Near Field Communications as a carrier technology is proposed. The solution works without any user interaction and can be applied for almost any data storage device: NFC or RFID tag, USB-flash drive, etc. The major novelty of the system is real-time encryption key generation algorithm. This approach doesn't require any computation power on the tag, trusted third parties or secure link between tag and information system. So far, the mentioned features transforms to significant advantages of the proposed solution, while compared to existing analogues: OAuth, Opacity and LMAP. At the same time, the integrity of key sequences is not guarantied, that brings motivation for future research in the field.