Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Enhanced Random Access and Beam Training for mmWave Wireless Local
  Networks with High User Density   As low frequency band becomes more and more crowded, millimeter-wave (mmWave)
has attracted significant attention recently. IEEE has released the 802.11ad
standard to satisfy the demand of ultra-high-speed communication. It adopts
beamforming technology that can generate directional beams to compensate for
high path loss. In the Association Beamforming Training (A-BFT) phase of
beamforming (BF) training, a station (STA) randomly selects an A-BFT slot to
contend for training opportunity. Due to the limited number of A-BFT slots,
A-BFT phase suffers high probability of collisions in dense user scenarios,
resulting in inefficient training performance. Based on the evaluation of the
IEEE 802.11ad standard and 802.11ay draft in dense user scenarios of mmWave
wireless networks, we propose an enhanced A-BFT beam training and random access
mechanism, including the Separated A-BFT (SA-BFT) and Secondary Backoff A-BFT
(SBA-BFT). The SA-BFT can provide more A-BFT slots and divide A-BFT slots into
two regions by defining a new `E-A-BFT Length' field compared to the legacy
802.11ad A-BFT, thereby maintaining compatibility when 802.11ay devices are
mixed with 802.11ad devices. It can also reduce the collision probability in
dense user scenarios greatly. The SBA-BFT performs secondary backoff with very
small overhead of transmission opportunities within one A-BFT slot, which not
only further reduces collision probability, but also improves the A-BFT slots
utilization. Furthermore, we propose a three-dimensional Markov model to
analyze the performance of the SBA-BFT. The analytical and simulation results
show that both the SA-BFT and the SBA-BFT can significantly improve BF training
efficiency, which are beneficial to the optimization design of dense user
wireless networks based on the IEEE 802.11ay standard and mmWave technology.

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The categories of this paper are: solv-int
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The categories of this paper are: chem-ph
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The categories of this paper are: math-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: q-fin
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The categories of this paper are: hep-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: stat
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The categories of this paper are: cond-mat
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The categories of this paper are: supr-con
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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: nucl-ex
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The categories of this paper are: math
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The categories of this paper are: funct-an
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The categories of this paper are: atom-ph