966 research outputs found
A Holistic Investigation on Terahertz Propagation and Channel Modeling Toward Vertical Heterogeneous Networks
User-centric and low latency communications can be enabled not only by small
cells but also through ubiquitous connectivity. Recently, the vertical
heterogeneous network (V-HetNet) architecture is proposed to backhaul/fronthaul
a large number of small cells. Like an orchestra, the V-HetNet is a polyphony
of different communication ensembles, including geostationary orbit (GEO), and
low-earth orbit (LEO) satellites (e.g., CubeSats), and networked flying
platforms (NFPs) along with terrestrial communication links. In this study, we
propose the Terahertz (THz) communications to enable the elements of V-HetNets
to function in harmony. As THz links offer a large bandwidth, leading to
ultra-high data rates, it is suitable for backhauling and fronthauling small
cells. Furthermore, THz communications can support numerous applications from
inter-satellite links to in-vivo nanonetworks. However, to savor this harmony,
we need accurate channel models. In this paper, the insights obtained through
our measurement campaigns are highlighted, to reveal the true potential of THz
communications in V-HetNets.Comment: It has been accepted for the publication in IEEE Communications
Magazin
THz Communications – A Candidate for a 6G Radio?
W the first 5G networks are about to be launched, the discussion within the scientific community about the next generation Beyond 5G or 6G has already kicked-off. One of the candidate technologies for a 6G radio access technology is THz communications, which uses spectrum mainly beyond 275 GHz enabling the use of channel bandwidths of several 10s of GHz. This contribution provides an overview on current state-of-the art of THz communications in research, standardization and regulation and discusses the challenges to make THz communications a promising candidate for a 6G radio
Reconfigurable Intelligent Surface Aided TeraHertz Communications Under Misalignment and Hardware Impairments
TeraHertz (THz) communications are envisioned to help satisfy the ever high
data rates demand with massive bandwidth in the future wireless communication
systems. However, severe path attenuation, transceiver antenna misalignment,
and hardware imperfection greatly alleviate the performance of THz
communications. To solve this challenge, we utilize the recently proposed
reconfigurable intelligent surface (RIS) technology and provide a comprehensive
analytical framework of RIS-aided THz communications. More specifically, we
first prove that the small-scale amplitude fading of THz signals can be exactly
modeled by the fluctuating two-ray distribution based on recent measurements.
Exact statistical characterizations of end-to-end signal-to-noise plus
distortion ratio (SNDR) and signal-to-noise ratio (SNR) are derived. Moreover,
we propose a novel method of optimizing the phase-shifts at the RIS elements
under discrete phase constraints. Finally, we derive analytical expressions for
the outage probability and ergodic capacity, respectively. The tight upper
bounds of ergodic capacity for both ideal and non-ideal radio frequency chains
are obtained. We provided Monte-Carlo simulations to validate the accuracy of
our results. It is interesting to find that the impact of path loss is more
pronounced compared to others, and increasing the number of elements at the RIS
can significantly improve the THz communication system performance
Low-Loss THz Waveguide Bragg Grating using a Two-Wire Waveguide and a Paper Grating
We propose a novel kind of the low-loss THz Waveguide Bragg Grating (TWBG)
fabricated using plasmonic two-wire waveguide and a micromachined paper grating
for potential applications in THz communications. Two TWBGs were fabricated
with different periods and lengths. Transmission spectra of these TWBGs show 17
dB loss and 14 dB loss in the middle of their respective stop bands at 0.637
THz and 0.369 THz. Insertion loss of 1-4 dB in the whole 0.1-0.7 THz region was
also measured. Finally, TWBG modal dispersion relation, modal loss and field
distributions were studied numerically, and low-loss, high coupling efficiency
operation of TWBGs was confirmed
Building an end user focused THz based ultra high bandwidth wireless access network: The TERAPOD approach
The TERAPOD project aims to investigate and demonstrate the feasibility of ultra high bandwidth wireless access networks operating in the Terahertz (THz) band. The proposed TERAPOD THz communication system will be developed, driven by end user usage scenario requirements and will be demonstrated within a first adopter operational setting of a Data Centre. In this article, we define the full communications stack approach that will be taken in TERAPOD, highlighting the specific challenges and aimed innovations that are targeted
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