Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Energy-Efficient Interactive Beam-Alignment for Millimeter-Wave Networks   Millimeter-wave will be a key technology in next-generation wireless networks
thanks to abundant bandwidth availability. However, the use of large antenna
arrays with beamforming demands precise beam-alignment between transmitter and
receiver, and may entail huge overhead in mobile environments. This paper
investigates the design of an optimal interactive beam-alignment and data
communication protocol, with the goal of minimizing power consumption under a
minimum rate constraint. The base-station selects beam-alignment or data
communication and the beam parameters, based on feedback from the user-end.
Based on the sectored antenna model and uniform prior on the angles of
departure and arrival (AoD/AoA), the optimality of a fixed-length
beam-alignment phase followed by a data-communication phase is demonstrated.
Moreover, a decoupled fractional beam-alignment method is shown to be optimal,
which decouples over time the alignment of AoD and AoA, and iteratively scans a
fraction of their region of uncertainty. A heuristic policy is proposed for
non-uniform prior on AoD/AoA, with provable performance guarantees, and it is
shown that the uniform prior is the worst-case scenario. The performance
degradation due to detection errors is studied analytically and via simulation.
The numerical results with analog beams depict up to 4dB, 7.5dB, and 14 dB
gains over a state-of-the-art bisection method, conventional and interactive
exhaustive search policies, respectively, and demonstrate that the sectored
model provides valuable insights for beam-alignment design.

5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
28
The categories of this paper are: alg-geom
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
0
The categories of this paper are: hep-ph
19
The categories of this paper are: eess
32
The categories of this paper are: atom-ph
27
The categories of this paper are: comp-gas
21
The categories of this paper are: adap-org
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The categories of this paper are: astro-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: q-bio
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The categories of this paper are: hep-lat