Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: LoRa beyond ALOHA: An Investigation of Alternative Random Access
  Protocols   We present a stochastic geometry-based model to investigate alternative
medium access choices for LoRaWAN---a widely adopted low-power wide-area
networking (LPWAN) technology for the Internet-of-things (IoT). LoRaWAN
adoption is driven by its simplified network architecture, air interface, and
medium access. The physical layer, known as LoRa, provides quasi-orthogonal
virtual channels through spreading factors (SFs) and time-power capture gains.
However, the adopted pure ALOHA access mechanism suffers, in terms of
scalability, under the same-channel same-SF transmissions from a large number
of devices. In this paper, our objective is to explore access mechanisms
beyond-ALOHA for LoRaWAN. Using recent results on time- and power-capture
effects of LoRa, we develop a unified model for the comparative study of other
choices, i.e., slotted ALOHA and carrier-sense multiple access (CSMA). The
model includes the necessary design parameters of these access mechanisms, such
as guard time and synchronization accuracy for slotted ALOHA, carrier sensing
threshold for CSMA. It also accounts for the spatial interaction of devices in
annular-shaped regions, characteristic of LoRa, for CSMA. The performance
derived from the model in terms of coverage probability, channel throughput,
and energy efficiency are validated using Monte-Carlo simulations. Our analysis
shows that slotted ALOHA indeed has higher reliability than pure ALOHA but at
the cost of lower energy efficiency for low device densities. Whereas, CSMA
outperforms slotted ALOHA at smaller SFs in terms of reliability and energy
efficiency, with its performance degrading to pure ALOHA at higher SFs.

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The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
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The categories of this paper are: adap-org
9
The categories of this paper are: nlin
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The categories of this paper are: ao-sci
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The categories of this paper are: gr-qc
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The categories of this paper are: dg-ga
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The categories of this paper are: comp-gas
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The categories of this paper are: astro-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: chem-ph
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The categories of this paper are: funct-an
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-lat
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The categories of this paper are: econ
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The categories of this paper are: math-ph