Page 9 - ITU Journal Future and evolving technologies Volume 2 (2021), Issue 7 – Terahertz communications

ITU Journal on Future and Evolving Technologies, Volume 2 (2021), Issue 7

LIST OF ABSTRACTS

Terahertz band communications as a new frontier for drone networks

Pages 1–19
Akhtar Saeed, Ozgur Gurbuz, Mustafa Alper Akkaş, Ahmet Ozan Bicen

Terahertz band (0.1‑10 THz) communications is one of the candidates for 6G systems due to intrinsic
massive bandwidth and data rate support. Having demonstrated the significant potential of THz band at
various atmospheric altitudes, in this article, we discuss the prospects of THz communications for drone
networks, more specifically, for Drone Sensor Networks (DSNs). For 6G non‑terrestrial communication
scenarios, drones will not only serve as on‑demand base‑stations, as supporting alternatives or
backhauls for the terrestrial base stations, but they will also provide seamless connectivity for
distributed monitoring and surveillance applications, which require an ultra‑reliable low latency service
for carrying multimedia data. THz band sensing will also provide additional sensing capabilities from
the sky to THz‑enabled DSNs. Presenting this vision, in this paper, we first discuss possible use cases
of THz‑enabled drone networks considering communication, sensing and localization aspects. Then,
for revealing the capacity potential of THz‑enabled drone networks, we provide motivating channel
capacity results for communication of drones at different altitudes, under ideal channel conditions with
no fading and realistic channel with beam misalignment and multipath fading. We further present major
challenges pertaining to employing the THz band for DSNs, addressing physical layer issues, followed
with spectrum and interference management, medium access control and higher layers and security,
while reviewing some prominent solutions. Finally, we highlight future research directions with
Artificial Intelligence (AI)/Machine Learning (ML)‑based approaches and mobile edge computing.
View Article

M-ary quadrature amplitude modulation order optimization for
terahertz wireless communications over dispersive channels

Pages 21–30
Karl Strecker, Sabit Ekin, John O'Hara

Highly accurate atmospheric models, based on molecular resonance information contained within the
HITRAN database, were used to simulate the propagation of high capacity single‑carrier quadrature
amplitude modulated signals through the atmosphere for various modulation orders. For
high‑bandwidth signals such as those considered in this work, group velocity dispersion caused by
atmospheric gases distorts the modulated waveform, which may produce bit errors. This leads to stricter
Signal‑To‑Noise Ratio requirements for error‑free operation, and this effect is more pronounced in
high‑order modulation schemes. At the same time, high‑order modulation schemes are more spectrally
efficient, which reduces the bandwidth required to maintain a given data rate, and thus reduces the total
group velocity dispersion in the link, resulting in less distortion and better performance. Our work with
M‑ary quadrature amplitude modulated signals shows that optimal selection of modulation order can
minimize these conflicting effects, resulting in decreased error rate, and reducing the performance
requirements placed on any equalizers, other dispersion‑compensating technologies, or signal
processing hardware.
View Article

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