Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Terahertz Wireless Channels: A Holistic Survey on Measurement, Modeling,
  and Analysis   Terahertz (THz) communications are envisioned as a key technology for sixth
generation (6G) wireless systems. The study of underlying THz wireless
propagation channels provides the foundations for the development of reliable
THz communication systems and their applications. This article provides a
comprehensive overview of the study of THz wireless channels. First, the three
most popular THz channel measurement methodologies, namely, frequency-domain
channel measurement based on a vector network analyzer (VNA), time-domain
channel measurement based on sliding correlation, and time-domain channel
measurement based on THz pulses from time-domain spectroscopy (THz-TDS), are
introduced and compared. Current channel measurement systems and measurement
campaigns are reviewed. Then, existing channel modeling methodologies are
categorized into deterministic, stochastic, and hybrid approaches.
State-of-the-art THz channel models are analyzed, and the channel simulators
that are based on them are introduced. Next, an in-depth review of channel
characteristics in the THz band is presented. Finally, open problems and future
research directions for research studies on THz wireless channels for 6G are
elaborated.

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The categories of this paper are: quant-ph
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The categories of this paper are: q-alg
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The categories of this paper are: cond-mat
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The categories of this paper are: comp-gas
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The categories of this paper are: bayes-an
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The categories of this paper are: alg-geom
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The categories of this paper are: nucl-th
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The categories of this paper are: stat
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The categories of this paper are: math-ph
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The categories of this paper are: adap-org
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The categories of this paper are: ao-sci
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ex
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The categories of this paper are: patt-sol
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The categories of this paper are: physics
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The categories of this paper are: acc-phys