464 research outputs found
Can Terahertz Provide High-Rate Reliable Low Latency Communications for Wireless VR?
Wireless virtual reality (VR) imposes new visual and haptic requirements that
are directly linked to the quality-of-experience (QoE) of VR users. These QoE
requirements can only be met by wireless connectivity that offers high-rate and
high-reliability low latency communications (HRLLC), unlike the low rates
usually considered in vanilla ultra-reliable low latency communication
scenarios. The high rates for VR over short distances can only be supported by
an enormous bandwidth, which is available in terahertz (THz) frequency bands.
Guaranteeing HRLLC requires dealing with the uncertainty that is specific to
the THz channel. To explore the potential of THz for meeting HRLLC
requirements, a quantification of the risk for an unreliable VR performance is
conducted through a novel and rigorous characterization of the tail of the
end-to-end (E2E) delay. Then, a thorough analysis of the tail-value-atrisk
(TVaR) is performed to concretely characterize the behavior of extreme wireless
events crucial to the real-time VR experience. System reliability for scenarios
with guaranteed line-of-sight (LoS) is then derived as a function of THz
network parameters after deriving a novel expression for the probability
distribution function of the THz transmission delay. Numerical results show
that abundant bandwidth and low molecular absorption are necessary to improve
the reliability. However, their effect remains secondary compared to the
availability of LoS, which significantly affects the THz HRLLC performance. In
particular, for scenarios with guaranteed LoS, a reliability of 99.999% (with
an E2E delay threshold of 20 ms) for a bandwidth of 15 GHz along with data
rates of 18.3 Gbps can be achieved by the THz network (operating at a frequency
of 1 THz), compared to a reliability of 96% for twice the bandwidth, when
blockages are considered.Comment: arXiv admin note: text overlap with arXiv:1905.0765
Seven Defining Features of Terahertz (THz) Wireless Systems: A Fellowship of Communication and Sensing
Wireless communication at the terahertz (THz) frequency bands (0.1-10THz) is
viewed as one of the cornerstones of tomorrow's 6G wireless systems. Owing to
the large amount of available bandwidth, THz frequencies can potentially
provide wireless capacity performance gains and enable high-resolution sensing.
However, operating a wireless system at the THz-band is limited by a highly
uncertain channel. Effectively, these channel limitations lead to unreliable
intermittent links as a result of a short communication range, and a high
susceptibility to blockage and molecular absorption. Consequently, such
impediments could disrupt the THz band's promise of high-rate communications
and high-resolution sensing capabilities. In this context, this paper
panoramically examines the steps needed to efficiently deploy and operate
next-generation THz wireless systems that will synergistically support a
fellowship of communication and sensing services. For this purpose, we first
set the stage by describing the fundamentals of the THz frequency band. Based
on these fundamentals, we characterize seven unique defining features of THz
wireless systems: 1) Quasi-opticality of the band, 2) THz-tailored wireless
architectures, 3) Synergy with lower frequency bands, 4) Joint sensing and
communication systems, 5) PHY-layer procedures, 6) Spectrum access techniques,
and 7) Real-time network optimization. These seven defining features allow us
to shed light on how to re-engineer wireless systems as we know them today so
as to make them ready to support THz bands. Furthermore, these features
highlight how THz systems turn every communication challenge into a sensing
opportunity. Ultimately, the goal of this article is to chart a forward-looking
roadmap that exposes the necessary solutions and milestones for enabling THz
frequencies to realize their potential as a game changer for next-generation
wireless systems.Comment: 26 pages, 6 figure
Potential key challenges for terahertz communication systems
The vision of 6G communications is an improved performance of the data rate and latency limitations and permit ubiquitous connectivity. In addition, 6G communications will adopt a novel strategy. Terahertz (THz) waves will characterize 6G networks, due to 6G will integrate terrestrial wireless mobile communication, geostationary and medium and low orbit satellite communication and short distance direct communication technologies, as well as integrate communication, computing, and navigation. This study discusses the key challenges of THz waves, including path losses which is considered the main challenge; transceiver architectures and THz signal generators; environment of THz with network architecture and 3D communications; finally, Safety and health issues
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